Fundamentals of refining
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Fundamentals of refining Fundamentals of refining Document Transcript

  • Course Code: MB-107 Course Name: Refining © UNIVERSITY OF PETROLEUM & ENERGY STUDIES
  • Contents Unit 1 Growth & Development of Refining Industry in India ................................... 1 Unit 2 Crude Oil and its Characteristics ...................................................................... 7 Unit 3 Specifications of Petroleum Products & Related Tests ................................ 23 Unit 4 Integrated Refinery & Petrochemical Plants ................................................. 53 Unit 5 Future Refining Scenario .................................................................................. 85 Unit 6 Advances in Petroleum Refining ..................................................................... 89 Unit 7 Hydrocarbon Loss Minimization ...................................................................... 93 Unit 8 Energy Conservation ......................................................................................... 95 Unit 9 Gross Refining Margin ...................................................................................... 99 Unit 10 Oil Accounting .................................................................................................. 103 Unit 11 Excise & Custom – Petroleum Products ....................................................... 107
  • Objective The objective of this course is to give an insight into various facets of petroleum refining for producing finished products of the desired specifications. Various refining processes used in the refineries have been dealt in this module. Characteristics of crude and specifications of various petroleum products have been explained in detail. Dealing with growth and development of petroleum refining industry in India, latest advancements in various technologies for improving profitability of the refineries in the face of increasingly stringent product specifications for meeting environmental stipulations have also been described.
  • An Overview Refining of petroleum for producing fuel and related products for automobiles, domestic consumption and meeting the needs of the power sector, petrochemicals, fertilizers etc. and other industries, is very vital for the economic progress of the country. The refining industry in India has made tremendous progress since independence with its march in time with the country's economic growth and overall progress. Starting with the establishment of the first public sector refinery at Guwahati (Assam) in 1962, it has come a long way with the setting up of most modern, state of the art and highly energy efficient refineries of the present day. India has 17 operating refineries processing both indigenous and imported crudes. The crude processing capacity of the country has increased from 6 MMTPA in 1962 to 113 MMTPA as of today. Oil companies in India have met the challenges of the petroleum market product demands with the desired stringent specifications from time to time, by making changes/ improvements in their processes while at the same time sustaining their profitability. The refineries are highly capital-intensive industries with a medium gestation period and produce crucial products for meeting the country's needs including that of defence. For setting up a 6 MMTPA capacity refinery complex with marketing facilities, investments to the tune of Rs 5000 crores are required. These refineries need to be run efficiently so as to make profits, and hence need to be modernised and updated from time to time. The module on refining covers various facets of petroleum refining. Various refining processes used in the refineries have been dealt with in this module. Characteristics of crude oil and specifications of various petroleum products have been explained in detail. Dealing with growth and development of petroleum refining industry in India, latest advancements in various technologies for improving profitability of the refineries in the face of increasingly stringent product specifications for meeting environmental stipulations have also been described.
  • 1 Unit 1 Notes __________________ __________________ Growth and Development of __________________ Refining Industry in India __________________ __________________ __________________ __________________ __________________ Objectives __________________ After studying the unit, the learner will be able to: __________________ y Get an overview of the growth of the Indian Refining Industry after independence. y Know about special features of Indian Refining Industry. y Get a good idea of various challenges facing the industry in the present time/in future and strategies for meeting the same. With the growth of industry and improvement in the living standard of people, demand for petroleum products is increasing rapidly. Consequently, there is a thrust on increasing their supply by enhancing refining capacity. First refinery in India started soon after oil production started in Digboi, Assam. Thereafter addition of refineries and capacity augmentation continued unabated. Now we are having seventeen operating refineries with a total capacity of 113 MMTPA. The Important Milestones 1866 - Oil discovery at Nahorpung, Assam. 1889 - Oil Production started at Digboi, Assam. 1893 - First Refinery started at Margharita, Assam. 1899 - Assam Oil Company was formed. 1901 - Digboi Refinery was commissioned supplanting the earlier refinery at Margarita. 1947- 1957 Setting up of three coastal refineries by Multi National Oil Companies (MNCs)
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 2 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Activity 1 A u 2 at Mumbai (Esso & Burmah Shell) Reader may like to draw a Geneological Chart of the current u 1 at Vizag (Caltex) refineries operative in India. Please classify by company, The MNCs were already marketing petroleum technology and year of products in India by then. establishment and expanded capacity wherever applicable by 1954 - Indian Oil exploration with the help of Russian the end of 10th 5 year plan i.e. 2006 – 07. Geologists. __________________ 1956 - Formation of Oil and Natural Gas Commission __________________ for exploration and production of crude oil and __________________ gas. __________________ 1958 - Discovery of Cambay oil field. __________________ __________________ 1958 - Indian Refineries Ltd (IRL) was formed in the __________________ public sector to install refineries and pipelines in India. __________________ __________________ - Oil India Ltd (OIL) was formed as a joint __________________ venture company between Government of India and Burmah Oil Co. 1959 - Indian Oil Company formed for marketing of petroleum products. 1962 - The first refinery in the public sector commissioned at Guwahati (0.75 MMTPA) under IRL. 1963 - Indian Oil Blending Ltd – A JV between Indian Oil Co. and Mobil Petroleum Co. Inc. was formed for manufacture of lube oils and greases. 1964 - IRL was dissolved and merged with Indian Oil Co. Ltd, to form Indian Oil Corporation Ltd (IOCL). 1974 - IOBL became part of IOCL. 1981 - Assets of erstwhile Assam Oil Co. were taken over and vested in IOC as Assam Oil Division (AOD). 1998 - Panipat Refinery of IOC commissioned.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 1 Growth and Development of Refining Industry in India 3 1999 - Reliance Petroleum Refinery at Jamnagar, Activity 1 B commissioned. What are various options for increasing the Refining Capacity 2000 - Numaligarh refinery commissioned. in the country? __________________ In the five decades since independence, 16 refineries have been added in the public/private/ joint sectors (including __________________ three in the private sector by MNCs, which subsequently __________________ became PSU’s). __________________ __________________ Future Outlook* (as per 2025 vision document) __________________ Total Refining Capacity __________________ MMTPA __________________ 2002 – 03 135 __________________ Barauni Expansion __________________ Haldia Expansion HPCL, Mumbai Expansion CPCL, Nagapatinam RPL Expansion Essar Oil 2003 – 04 170 Koyali Expansion Panipat Expansion BPCL Expansion CPCL Expansion BRPL Expansion Paradip Essar Oil Expansion Nagarjuna Oil 2004 – 05 176 Kochi Refinery Expansion 2005 – 06 214 Essar Oil Expansion RPL Expansion Bhatinda 2006 – 07 221 BRPL Expansion Bina * The anticipated growth in petroleum products may not take place
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 4 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes Refining Capacity in India as in the year 2002 __________________ No. Refineries MMTPA Year of __________________ Commissioning __________________ 1. Indian Oil Corporation Limited, Digboi 0.65 1901 __________________ 2. Indian Oil Corporation Limited, Guwahati 1.00 1962 __________________ 3. Indian Oil Corporation Limited, Barauni 3.30 (6.0) 1964 __________________ 4. Indian Oil Corporation Limited, Koyali 13.5 (18) 1965 __________________ 5. Indian Oil Corporation Limited, Haldia 3.75 (7.5) 1974 __________________ 6. Indian Oil Corporation Limited, Mathura 7.50 1982 __________________ 7. Hindustan Petroleum Corporation Limited, Vizag 7.50 1975 __________________ 8. Hindustan Petroleum Corporation Limited, Mumbai 5.50 1954 9. Bharat Petroleum Corporation Limited, Mumbai 8.90 1955 10. Cochin Refineries Limited, Cochin 7.50 (10.5) 1966 11. Chennai Petroleum Corporation Limited, Chennia 6.50 (9.5) 1969 12. Bongaigaon Refineries Limited, Bongaigaon 2.35 1972 13. Madras Refineries Limited (CBR), Nagapatinam 0.50 1994 14. Mangalore Refineries & Petrochemicals Ltd., Mangalore 6.00 (9.0) 1995 15. Indian Oil Corporation Limited Panipat 6.00 1998 16. Reliance Petroleum Limited, Jamnagar 27.00 1999 17. Numaligarh Refineries Ltd., Numaligarh 3.00 2000 Total Capacity 112.45 Indian Refining Industry – Emerging Scenario u Shifting product demand u Stringent product specifications u Stringent environmental regulations u Feedstock quality deterioration u Globalisation u Deregulation of oil and gas sector Indian Refining Industry – Special Features u Larger requirement of middle distillates (diesel, kerosene) u Prevalence of old as well as modern technologies
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 1 Growth and Development of Refining Industry in India 5 u A few refineries with size far lower than world Activity 1 C standards. i. Describe special features of Downstream Industry. Strategies for Indian Refineries ii. Challenges faced and strategies to meet the same. u Residue upgradation technologies for heavy crudes __________________ u Technologies for producing lighter fuels __________________ u Process technologies to improve quality with respect to: __________________ __________________ – performance parameters __________________ – eco-friendly products __________________ u Value addition to refinery streams __________________ u Increased emphasis on Process Control/ Automation __________________ __________________ u Evolutionary/innovative technological changes expected __________________ rather than revolutionary ones u Refineries to be integrated ,compact and flexible with respect to crude/ product mix. Future Technological Challenges u Meeting higher demand of petroleum products (viz. distillates) u Meeting higher standards of product qualities u More emphasis on environment u Value addition to refineries u Technologies to improve margins u Zero emission refinery Capacity Increase (To Meet Demand of Petroleum Products ) u Low cost revamps/ addition of units u Run length improvement of units u Infrastructure development for crude receipt/storage/ distribution u Installation of matching secondary processing plants.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 6 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes Value Addition __________________ u Production of value added products from refinery __________________ streams __________________ u Propylene, butene – 1, butene – 2, N – Paraffin, Lab, __________________ Benzene, Toluene, Hexane, P – Xylene etc. __________________ __________________ u Generation of power from heavy ends __________________ Distillation Range Improvement __________________ __________________ u New residue conversion technologies like FCC, Hydrocracker, RDS-RFCC __________________ u Advanced controls and optimisation u Advanced catalysts u Continuous simulation of plants/ product mix through computer models u Prudent selection of technologies and proper integration of secondary units/ plants. Review Questions 1. Please identify technological challenges that refineries will face in future.
  • 7 Unit 2 Activity 2 A How is the crude oil formed? __________________ Crude Oil and Its __________________ Characteristics __________________ __________________ __________________ __________________ __________________ Objectives __________________ After studying the unit, the learner will be able to: __________________ y Understand the chemistry of petroleum, different types of crudes __________________ and their characteristics. y Develop an insight into the significance of various characteristics of crudes and method of determination of the same. y Get an idea of various crudes used in Indian Refineries. y Appreciate the difference between Indian crudes and typical middle east crudes. Crude Oil Characteristics and its Significance (General Information) Crude oils are formed by the action of geological processes on the remains of ancient marine life. It is a complex mixture of hydrocarbons and over 16,000 compounds have been identified in one sample. Composition varies widely: – By geographical location – Mix of individual wells – Variance of wells with time Chemistry of Petroleum Crude oil contains almost all known hydrocarbons and non- hydrocarbons. As it is drawn from the earth, it also contains impurities like water, mud and salts which get associated during its production and transportation.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 8 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Activity 2 B Crude oil, the basic raw material of refining industry, is a What are the type of hydrocarbons mixture of eight different hydrocarbon families: present in the crude? __________________ i. Paraffins __________________ ii. Cyclopentanes __________________ iii. Cyclohexanes __________________ __________________ iv. Cycloheptanes __________________ v. Di-cyclo-paraffins __________________ vi. Benzenes __________________ __________________ vii. Aromatic cycloparaffins __________________ viii. Dinuclear and polynuclear Aromatics are present in smaller amounts in compounds containing metallic constituents such as Vanadium, Nickel, Iron, Copper, Magnesium, Calcium, Zinc, Titanium etc. Besides impurities such as Sulphur, Nitrogen and Oxygen compounds mostly present in high boiling point fractions are also present in crude oil. Based on boiling point, the fractions are separated and given secondary treatment to utilise it as finished products. Based on proportion of types of hydrocarbon, it can be divided into Paraffin, Napthenic and Aromatic categories. The purely hydrocarbon content may be as high as 97% and as low as 50% for heavy crude oils. The non-hydrocarbon portion retains hydrocarbon characteristics as the molecules contain one or two atoms of elements other than carbon and hydrogen. The carbon content is between 83 to 87% and hydrogen content between 11 to 14%. The ratio of carbon to hydrogen increases from the low to high molecular weight fraction due to increase in polynuclear aromatic and multi ring cycloparaffins in these higher boiling fractions. Atmospheric distillation is adopted for separating the compounds present into various fractions upto 366ºC:- i. Overhead gases containing mainly methane, ethane, propane and butane. ii. C5–90º C light naptha iii. 90ºC–140ºC heavy naptha iv. 140ºC–204ºC Mineral Turpentine Oil (MTO)
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 2 Crude Oil and its Characteristics 9 v. 140ºC–240ºC Aviatin Turbine Fuel (ATF) Activity 2 C i. How do you classify crudes vi. 140ºC–270º Kerosene based on proportion of type of hydrocarbon present in them? vii. 270ºC–340ºC Gas oil ii. What is Crude Assay? How are these Assays utilized? viii. 340ºC–366ºC Jute Batching Oil (JBO) __________________ 366ºC plus fraction i.e. Reduced Crude Oil (RCO) is subjected __________________ to vacuum distillation for obtaining vacuum gas oils, raw __________________ Lube Distillate and short residue. Various fractions obtained __________________ from atmospheric and vacuum distillation are given further __________________ treatment to meet required specifications for use. __________________ Crude Assay __________________ __________________ Crude Assay is the determination of properties of various __________________ fractions of crude oil. This is done to assess the utility __________________ of the crude for processing for production of various products and their yields. Crude Assay Data are utilised for the following: u Crude oil selection u Crude oil grading u Crude valorization u Crude swapping u Crude imports u Creation of new infrastructure at the existing refineries u Grassroot refineries u Production planning management u Inventory problems u Demand/supply gaps Types of Evaluations Preliminary Assay u Crude characteristics – Consistency of crude supply.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 10 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes Short Evaluation __________________ u Crude characteristics u Absorption of new __________________ crude in fuel refinery __________________ __________________ u TBP assay u To study the change in __________________ quality of crude over a period of time __________________ __________________ u Yield data and key u Detailed characteri- __________________ characteristics of straight sation of crude oil __________________ run cuts in fuel range and including all micro long residue constituents. __________________ Detailed Evaluation u Design data for grass u TBP assay in root refinery atmospheric and vacuum range u Product optimisation u Selection and design of secondary conversion units. u Yield and characterist- ics of sets of distillates in atmospheric and vacuum range with variation in IBP, FBP characterisation of several long and short residues. Information Required u Base and general properties of crude oil u Presence of impurities u Operating and design data – Fractionating or TBP distillation curves – Equilibrium of flash vaporization curves – API or specific gravity curves of each fraction distilled.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 2 Crude Oil and its Characteristics 11 u Property curves of fractions vs% distilled Notes __________________ – Mid% curves __________________ – Yield% curves __________________ __________________ – ISO% curves __________________ u Properties and yield of straight run fractions and __________________ residues __________________ u Detailed composition of light distillates __________________ __________________ u Hydrocarbon Type Distribution of Middle and Heavy __________________ Distillates Characteristics of Crude Oil Basic Properties Impurities Density & API Water Content Reid Vapour Pressure (RVP) Salt Content Light End Analysis BS & W Pour Point Sulphur Content Viscosity Nitrogen Content Wax Content Inorganic and Asphaltenes Total Acid Carbon Residue Trace Metals Ash Content Distillation Characteristic (D86 or D285) Base of Crude Oil Crude Oil Characteristics and their Significance Density Density is used for: u Weight to volume or vice versa calculations u Checking the consistency of crude supply u Control of refinery operations u Used in various correlations
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 12 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes u Also gives a rough indication of type of crude oil __________________ MASS (M) __________________ Density = VOLUME (V) __________________ __________________ M/V Specific GRAVITY= __________________ M’/V (WATER) __________________ __________________ 141.5 API GRAVITY= –131.5 __________________ SP.GR AT 60/60°F __________________ __________________ Examples: Water = 10 API Kerosene = 45 API Motor Gasoline = 58 API Natural Gasoline = 75 API Crude oils are categorised based on gravity Light grades : Above 33 degree API Medium grades : 23-33 degree API Heavy grades : upto 22 degree API CRUDE Density API TYPE TOTAL DISTILLATE UPTO 370ºC Narimanam 0.7920 47.08 I 79.6 Ankleshwar 0.7930 46.85 I 78.2 Jotana 0.8161 41.80 P 52.0 Bombay High 0.8278 39.35 I 65.4 Heera 0.8412 36.62 I 60.6 Kalol 0.8414 36.55 P 47.0 Rumaila 0.8448 35.90 I 55.7 Ratna 0.8484 35.20 I 51.0 Rostam 0.8495 35.00 I 59.7 Jhalora 0.8496 35.16 I 42.1 Basrah 0.8527 34.40 I 52.5 Sobashan 0.8549 33.99 P 43.0 N. Gujarat 0.8553 33.85 I 44.0 Geliki 0.8675 31.50 I 54.5 Nahorkatiya 0.8688 31.30 I 60.9 Kuwait IF IR. 0.8698 31.10 I 47.0 Oman Elmorgan 0.8727 30.55 I 48.1 Jorajan 0.8821 28.84 N 60.7 Kharsang 0.8910 27.22 N 61.7 Lakwa 0.8952 26.50 N 53.7 Jhalora 0.8986 25.87 I 31.8 Kothana 0.9000 25.64 I 28.2 Rudrasagar 0.9210 22.10 N 60.3 Sanand 0.9242 21.45 I 24.4 N- Kadi Mix 0.9340 19.91 I 27.6 Badarpur 0.9430 18.39 N 60.6 Santhol 0.9507 17.29 I 22.9
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 2 Crude Oil and its Characteristics 13 Sulphur Notes __________________ Crude oils are also categorised based on sulphur. __________________ u Sulfur is a measure of “sourness” and “sweetness” of __________________ crude __________________ - Sweet grades<0.5% of Sulphur __________________ __________________ - Sour grades >0.5% of Sulphur __________________ Sulphur is passed on to products as much as regulations or __________________ market accepts. It is removed in hydrotreater by reacting __________________ with H2 and recovered as elemental sulfur in SRU. __________________ Reid Vapour Pressure (RVP) and Light End Analysis RVP indicates relative Percentage of gaseous and lighter hydrocarbons in crude oil. Component RVP, Kg/cm2 Propane 14.1 Kg/cm2 Butane 6.6 Kg/cm2 Crude Oil 0.01-0.05 Light end analysis carried out by GLC actually gives the percentage of hydrocarbons upto C5 and is the basis of assessing the LPG potential of crude. TYPICAL HYDROCARBON ANALYSIS Components % WT on Crude C1 ND C2 TRACES C3 0.1 ISO-C4 0.1 N-C4 0.3 ISO-CS 0.3 N-C5 0.5 TOTAL 1.3
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 14 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes Flow Characteristics of Crude Oils __________________ __________________ Characteristics BH Crude Basrah Crude __________________ WAX, % WT 10.9 3.5 __________________ Pour Point,°C +30 -24 __________________ Viscosity Kinematic cst __________________ AT 37.8 °C, 50°C 4.30, 3.32 6.18, 4.84 Geological Characteristics __________________ Yield Value Dynes/ cm2 AT __________________ 32°C 45.0 2.0 __________________ 24°C 85.0 5.0 __________________ 18°C 222.0 10.0 16°C 330.0 12.5 Plastic Viscosity, C.P. AT 32°C 7.9 9.6 24°C 30.7 14.7 18°C 43.7 16.0 16°C 45.0 17.3 Pour Point u Indicates relative amount of wax present in crude oil u Is the temperature below which pumping and transportation problems may be encountered u Along with viscosity, is used in pumping and design calculations: Wax Content Normal paraffins above C16 are solid at somewhat ambient temperatures. These hydrocarbons u Affect the flow behaviour of crude u Affect the product quality of gas oil, VGO and asphalt u Lube manufacture is also dependent on wax content of the crude. Salt Content It is measure of contamination in crude that will cause overhead corrosion or foul up exchangers by settling and
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 2 Crude Oil and its Characteristics 15 sealing. It is removed in desalter by washing and settling Activity 2 D mainly chlorides and sulphates of Na, K, Ca, Mg. i. How do you separate various fractions present in crudes? Resins Waxy Agglomerates ii. What are various impurities in Particulates crudes, their bad effects and how are these impurities Brine Droplet removed? iii. Method of determination of Asphaltenes Na+ Na+ salt content, BS&W & Viscosity. COO- COO- Alkyl Benzene __________________ __________________ Naphthenates Carboxylates __________________ __________________ FIGURE 2.1 POSTULATED STRUCTURE OF STABLISED EMULSION __________________ Problems Encountered Due to Salts __________________ __________________ u Irregular behaviour in distillation __________________ u Equipment corrosion in the atmospheric distillation __________________ caused by HCL liberated due to hydrolysis of chlorides __________________ Increased Consumption of Amonia u Salt is a major cause of blocking and fouling of heat exchangers u Residual product contamination 100 • Total Chloride evolved as HCL % Ashci % 75 • • 50 • 25 • • 0 0 100 200 300 400 Salt Content of Crude PTO AS NACL PTB as u Salts may vary widely in ratio of metal ions, though common averages are – Na: 70-75%, Mg: 15-20%, Ca: 10%.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 16 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes u Mg is most prolific producer of HCL with Ca and Na in __________________ descending order __________________ u Small quantities of HCL may substantially enhance __________________ corrosion of sulphur compounds __________________ __________________ Methods for Determination of Salt Content __________________ 1. IP 77/72 Extraction with water KCNS/Ag No 3 __________________ titration __________________ 2. ASTM D3230 Conductivity measurement based on __________________ calibration with Na, Ca, Mg chlorides __________________ standard solutions in mixed alcohol. Sediment and Water — Sediment has no relationship with salt but both might increase with connate water – Sediment Fine particles of sand clay, volcanic ash, drilling mud, rust, iron sulphide, metals and scale – Damaging Effects Plugging Abrasion and residual product contamination – Water causes irregular behaviour in distillation. Sediment in crude oil is measured by the following methods: BS & W ASTM D 96 Sediment by extraction ASTM D 4007 Water content DEAN & STARK ASTM D 4006 – Sediment in crude is determined for custody transfer purposes – Lower the sediments and water, higher the reliability of the unit. It is also a major pointer for corrosive materials in crude.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 2 Crude Oil and its Characteristics 17 Asphaltenes, Carbon Residue and Ash Content Activity 2 E Significance of TAN & KUOP. Asphaltenes __________________ u Are polynuclear condensed aromatic hydrocarbons __________________ having high molecular weight __________________ __________________ u These are insoluble in heptane and soluble in Benzene/ __________________ Toluene __________________ u Asphaltenes and carbon residue indicate the extent to __________________ which heavy hydrocarbons are present in crude oil. __________________ Ash Content __________________ __________________ u Metallic constituents concentrate in the ash of the crude oil Carbon Residue It’s a carbonacous residue formed after evaporation and pyrolysis of the sample. The residue is coke and determined by – Conradson residue method ASTM D 189 – Ramsbottom carbon residue ASTM D 624 – Micro-carbon residue method ASTM D 4630 Viscosity It is a measure of resistance to flow and is an important parameter for effective desalting. It is also highly dependant on temperature. High viscosity crudes need high temperatures for effective desalting. There is a limit for temperature in desalters operation. KUOP It is a measure of parafinity vis-à-vis aromaticity of crude. High KUOP is desired for high conversion in FCC, aromatic molecules cannot be cracked in FCC. They will simply take a ride through the plant.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 18 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Activity 2 F TAN What are various crudes processed in Indian Refineries? TAN is actually Total Acid Number. Where are Indigenous crude It is a measure of Naphthenic Acid (NA) contents in crude. found? What is the sulphur content of Indian crudes? This leads to corrosion in various sections of the unit. Over __________________ 1,500 known NA species are present in crude. __________________ All napthenic acids are not corrosive. Latest research __________________ indicates that TAN is not a complete Corrosion Index. __________________ TAN with 2.5 may corrode at higher rate than TAN with __________________ say 6 ! __________________ Detailed metallurgical reviews and monitoring mechanisms __________________ must be put in place. __________________ Selection of Crude Oil __________________ __________________ Technology trends in petroleum refining are driven by the external forces of product demand, product specifications (including environmental consideration), feed stock quality and availability. Crude oil will gradually become heavier and higher in sulphur content. Refineries, of late, have been sincerely attempting to produce fuels to comply with stricter environmental regulations particularly gasoline and diesel and are in the process of reducing the sulphur levels in distillates and fuel oil. Attention is now also being paid to reduce lead and benzene levels in gasoline. Various gasoline and diesel specifications applicable worldwide are given in the later part of this chapter. Crude processed in India are: 1. Indigenous crude oil sources a. Bombay high and satellite fields b. North Gujarat and Ankaleshwar crude c. Assam crudes d. KG Basin-Rava crude e. Cauvery Basin crude All the above crudes are low sulphur =<0.5% wt, low metal content, poor potential to yield LOBS and bitumen, and some are waxy in character.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 2 Crude Oil and its Characteristics 19 2. Imported crudes are sourced mostly from: Activity 2 G What straight run fractions are a. Gulf Region obtained in Atmospheric Distillation? And in Vacuum b. Nigeria Distillation? c. Malaysia __________________ __________________ d. Australia __________________ The above crudes are specially selected for production of __________________ Bitumen/LOBS/ATF, beside fuel products. __________________ These crudes are having varying range of sulphur from low __________________ of high. __________________ Comparison of Crudes __________________ __________________ Comparison of Indian crudes and typical Middle-east crude __________________ mix for yield and key properties of straight run cuts:- 1. Gases upto 20ºC 4. GAS OIL 250–370ºC 2. Naphtha I.B.P.- 140ºc 5. Vacuum GAS OIL 370–530ºC, 3. KEROSENE 140-250ºC 6. Short Residue 530º, C+. 1 1-2 AROW 5.8% VOL. 0.4 3.8 AROM. 16% Vol NAPH 40.6% NAPH. 52% VOL 4.4 AROM: 6.6% 2 V.O.N.O. 24.9 COTANE NO. 15.0 VOL 73.7 SMOKE PT. 23 10-1 OCTANE No. mm AROM. 1:1 % 67.5 VOL F.P.T.-54ºC SMOKE POINT SMOKE POINT 14mm 27mm 3 Arom. 36% 17.6 DIESEL INDEX 57 19.2 AROM. 15% VOL. 22.3 VOL. POUR POINT +3 F.P.T.–48ºC E.P.T.<–60ºC DIESEL INDEX DIESEL INDEX KUOP 12.10 67 POUR +POINT 23.9 33 KIN VISC. AT 31.2 POUR POINT 27.1 100º C +6ºC 4 –9ºC 8.120 SI KUOP 12-70 KIN. VISC. AT 18.8 KUOP II-61 ºAPI 13.58 100ºC KIN. VISC. AT POUR POINT 34.7 405 0St 5 96.9ºC +48 7 0St 27.2 API 16.5 KIN. VISC. AT 100ºC 150(27 0SI CCR 9.92% WI. POUR POINT + 6.3 CCR 14.77% Wt. 6 ºAPI 3.8 68ºC N.9 ASSAM CRUDE NORTH GUJARAT GANDHAR+ANKLE- MIX ºAPI 29.85 CRUDE MIX SWAR (60. 40 VOLT SULPHUR 0.24% ºAPI 26.83 CRUDE MIX Wr. POUR POINT SULPHUR 0.17%Wt. ºAPI 46.9 +30ºC WAX POUR POINT+21 SULPHUR 0.041 % Wt. CONTENT 10.8% WAX CONTENT POUR POINT+27ºC Wt. 6.8% Wt WAX CONTENT 8.9% KUOP 11.30 KUOP 12.0 Wt.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 20 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes 1.9 2.7 2.1 __________________ ARON 21.3% ARON 4% VOL. AROM 7.3% VOL VOL. NAPH. 25% OCTANE 10.7 18.6 30.4 OCTANE No. 53.8 __________________ VOL OCTANE NO.61.9 NO. 69-6 SMOKE POINT __________________ 26mm SMOKE POINT AROM. 18.6% __________________ 17mm VOL. F.P.T.–56ºC AROM. 26.9% 20.9 SMOKE POINT 24.7 16.1 __________________ VOL. F. PT. -49ºC 27mm Arom. 16% DIESEL INDEX Vol,. F. PT–57ºC 58 DIESEL INDEX POUR +POINT __________________ –9ºC 56 DIESEL INDEX 18.1 POUR POINT 24.0 58 21.8 KUOP 11-94 __________________ +3ºC POUR POINT KIN. VISC. AT –12ºC 100ºC __________________ KUOP 12.37 KIN 5.98 0St 22.5 __________________ VISC. AT 98.9ºC KUOP 12.31 KIN 28.4 15.7 API 7.43 5.36 0St VISC. AT 100ºC CCR 19.85% Wt. __________________ 4.83 0St POUR POINT + ºAPI 9.51 54ºC CCR 19.2% Wt. API 16.35, CCR KIN. VISC. AT 30.5 6.2 4.7 100ºC POUR POINT 10.4 % Wt POUR +72ºC POINT+ 60ºC 903.650St BOMBAY HIGH ºAPI NARIMANAM Kuwait+Lt. IRANIAN 39.35 SULPHER CRUDE FOMAN (56: 36: 6 VOL. ) 0.17% Wt. POUR ºAPI 47.08 ºAPI 31.1 POINT+ 30ºC WAX SULPHUR 0.085% SULPHUR 2.28% Wt. CONTENT 10.6% Wt. POUR POINT 0 POUR POIN T(–30ºC Wt. KUOP 11.70 WAX CONTENT WAX CONTENT 1.1% 2.8% Wt. KUOP Wt. KUOP II.98 11.98 Selection of Crude(s) for a Refinery Based on product demand, type of products, processing schemes of refineries, metallurgy of existing plant and equipment, crudes are selected after evaluating detailed crude Assay Data. Mostly, a mixture of crudes is selected for a refinery to optimise the cost and meeting products quality specifications. Review Questions 1. Describe different characteristics of crudes dealt with in this unit, their significance and typical values/ units of measurement. 2. Draw a comparison of indigenous crudes with Typical Middle East Crude(s) vis-à-vis important specifications of Petroleum Products.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 2 Crude Oil and its Characteristics 21 3. From which Indian crudes, can you produce Notes __________________ a. ATF __________________ b. Bitumen __________________ __________________ c. Lubes __________________ d. Micro-crystalline wax __________________ e. Good Quality Calcined Petroleum Coke __________________ __________________ __________________ __________________
  • 23 Unit 3 Notes __________________ __________________ Specifications of Petroleum __________________ Products and Related Tests __________________ __________________ __________________ __________________ __________________ Objectives __________________ After studying the unit, the learner will be able to: __________________ y Understand the specifications of various petroleum products, their significance and their determination/tests. y Appreciate crucial specification of HSD & MS from Environmental Pollution Standpoint & Strategies for meeting stringent norms for future Euro III/IV, Bharat III/IV. Specifications What are Specifications? Any material which is intended for use in a particular application should have certain characteristics so that it is suitable for use in that application. These characteristics are quantified to make them absolute and also to remove any ambiguity in the interpretation. These quantified characteristics are called “specifications”. Some important tests conducted on petroleum products and included in specifications: Flash Point RON Color Pour Point MON BMCI Distillation AKI Bromine Number Copper Corrosion Cetane Number Benzene Content Silver Corrosion Cetane Index Density Sulphur Smoke Point Sediment Viscosity Aniline Point Water Potential Gum Carbon Residue Weathering Test Existent Gum Vapour Pressure
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 24 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes Significance of Tests __________________ __________________ Flash Point __________________ It is the minimum temperature at which the sample gives __________________ sufficient vapour which forms an explosive mixture with air __________________ giving a flash when a flame is applied to it under conditions __________________ of the test method. __________________ Flash point is associated with safety during storage and __________________ application in some respects. When a product like kerosene __________________ is stored either at home or at a commercial location, it forms __________________ vapour above it depending upon the ambient temperature. If the vapour so formed is sufficient to form an explosive mixture with air, there would be explosions when a small naked flame is exposed to it. Each country has it own legislation with respect to flash point depending upon the climatic conditions of the country. Pour Point When heavy petroleum oils containing wax are allowed to settle (like in storage tanks), wax separates out from them making the oil immobile. If the oil does not move, it cannot be pumped. The temperature at which the oil becomes immobile (does not move) is termed as pour point when tested under the conditions of the test methods. Distillation The volatility of an oil is indicated by its distillation characteristics. Unlike pure compounds, petroleum oils are mixtures of several hydrocarbons and so will have a boiling range instead of boiling point. The oil should have suitable boiling range (volatility) so that it can be used in a particular application. For example, Motor Gasoline which is used in spark ignition internal combustion engines, has the following specifications for distillation: Recovery upto 70o C 10 to 45% Min Recovery upto 100o C 40 to 70% Min Recovery upto 180o C 90% v Min
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 3 Specifications of Petroleum Products & Related Tests 25 Since the application is in a spark ignition engine, the Notes fuel should easily vaporise to a sufficient degree so that __________________ when a spark is applied it can ignite. The specification for __________________ recovery at 70 o C is laid to meet this requirement. The __________________ maximum limit of 45% is laid to prevent some other __________________ undesirable effects such as vapour lock. This quality is called __________________ “easy start”. __________________ The specification for recovery at 100oC is set to give power __________________ to engine and take load. __________________ __________________ The specification for recovery at 180oC and final boiling point __________________ are set to prevent crank case oil dilution and unburnt hydrocarbon in tail gases (air pollution). Copper Corrosion The fuel product comes on contact with metal parts such as transfer pipe from storage tank, storage tank itself, the burner in a kerosene stove, stove body itself, storage and transportation equipment like pumps, storage vessels etc. If the product is corrosive, it will corrode these parts and reduces their life. Copper corrosion test indicates whether the product is corrosive to copper containing alloys or not. This test is applicable to all fuels. Silver Corrosion This test is done for Aviation Turbine Fuel (ATF)–Jet A1 Type Some aircrafts of civil aviation and defence use a silver lining in the fuel transfer lines. In order to protect this lining, the fuel should not be corrosive to silver. Hence this test is done for ATF. This is a requirement for Indian region only. Western countries and USA do not use this test any more. Sulphur Sulphur, besides being corrosive to the fuel systems, is a pollutant to the air and affects life. Global efforts are being made to minimise the sulphur content in motor gasoline, high speed diesel and fuel oils.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 26 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes Viscosity __________________ Viscosity is the resistance to flow. The unit of absolute or __________________ dynamic viscosity is Poise and that of kinematic viscosity is __________________ Stoke. Viscosity is an important property for lube oils __________________ because it gives the lubricating property to the oil. This is __________________ required to prevent wear and tear in the moving parts of a __________________ machine on account of metal to metal contact. For fuel oils, __________________ it gives flow properties which are needed for pump selection __________________ for transporting. __________________ Viscosity is measured in several ways. The most common __________________ are Kinematic Viscosity measured in centi-stokes and Saybolt Universal Viscosity measured in seconds. Potential Gum This test is applicable to motor gasoline which may contain unsaturated hydrocarbons (olefins). Olefins are oxidised by atmospheric oxygen to a gummy material which sticks to the carburetor jet of the vehicle or inlet valve leading to valve sticking which in turn results in the malfunction of the engine. This type of gum is characterised by Potential Gum test. It does not show the exact amount of gum that would form on storage but gives a directional indication. The unit of measurement is mg per liter. Existent Gum This test is applicable to motor gasoline. If motor gasoline contains any soluble solid residue, the residue gets deposited in the carburetor and other parts after the gasoline is vaporised. Such deposit may clog the jet and prevent fuel flow due to which the engine stops. That is why this test is done on MS. The specification is 40 mg per litre max. One point should be noted. Some solid material is added to MS deliberately for some purposes. Example: Dye to identify the MS from others. These type of residues are excluded from the specification.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 3 Specifications of Petroleum Products & Related Tests 27 Octane Number Notes __________________ It is defined as the per cent volume of iso octane in a mixture __________________ of iso octane and normal heptane that gives the same __________________ knocking as that of the fuel when tested under defined conditions. __________________ __________________ Iso octane is assigned a value of 100 and normal heptane 0 __________________ octane number. __________________ Normal paraffins have the lowest octane number. Next comes __________________ napthenes followed by iso paraffins, olefins and aromatics __________________ for the same carbon number. However, this is only a general __________________ rule and may differ in the case of iso paraffins. Some of them have lower octane numbers than corresponding napthenes and some other higher octane number depending upon the branching of the iso paraffin. Similarly Octane numbers of olefins may also differ slightly as given below: l n-Hexane 24.8 l Cyclohexane 83 l 2,2 Dimethy 1 Butane 91.8 l 2-Methyl Pentane 73.4 l Hexene-2 90 l Benzene >100 l N-Heptane 0 l Methyl Cyclohexane 75 l 2,3 Dimethyl Pentane 88 l 2 Methyl Hexene-1 92 l Toluene 107 Octane numbers are not truly additive. When used singly, the hydrocarbons behave in some way and when used in a mixture, they behave in another way. For example, Toluene has a RON 107 when it is a single component system. But when it is mixed with other hydrocarbons, it behaves as if its octane number is > 120. Some schools of thought say that in multi-component systems, like naptha, octane number is additive on weight percent basis. Some others believe that it is additive on mol.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 28 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes per cent basis. In effect, there are always some exceptions __________________ and some deviations. __________________ Research Octane Number and Motor Octane Number. __________________ __________________ These are determined under different conditions of the test. __________________ Test Condition RON MON __________________ Engine speed 600 RPM 900 RPM __________________ __________________ Spark advance 13 o Variable __________________ Mixture Temp -- 300 o F __________________ In Take Air Temp 125o F 100 o F AKI (Anti Knock Index) It is defined as the average of RON and MON. AKI = (RON + MON)/2 Anti Knock Index is regarded as more critical for engine performance than RON alone. Cetane Number This test is applicable to diesel fuels which use ignition by compression. Cetane number is defined as the per cent volume of n-cetane in a mixture of n-Cetane and alpha methyl naphthalene that would give the same knocking as that of the fuel under test. n-Cetane is assigned a value of 100 and alpha methyl naphthalene a value of 0. Alpha methyl naphthalene has some storage stability problem. It turns red when exposed to air. So, although it is a primary fuel, a secondary fuel for routine use is also stated in the test method. This is hepta Methyl Nonane (HMN). Another consideration for using HMN is its easier availability. This test has reverse characteristics of octane number. Here, normal paraffins have highest cetane number followed by naphthenes, iso paraffins, olefins and aromatics in general
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 3 Specifications of Petroleum Products & Related Tests 29 but the order may vary depending upon the chain length of Notes iso paraffins. __________________ __________________ Cetane Index __________________ It is an alternative to cetane number. It is nearly equal to __________________ cetane number but not an actually determined value required __________________ cetane engine. Cetane index is not applicable to fuels __________________ containing cetane improves. __________________ Smoke Point __________________ __________________ Smoke point is defined as the maximum length of the flame which does not give smoke when tested under prescribed __________________ conditions using the prescribed apparatus. Smoke point shows the hydrocarbon nature of the fuel. Paraffins have high smoke points followed by naphthenes and then by aromatics. The test is applicable primarily to kerosene. The main purpose of kerosene is for use in lantern. If the kerosene gives smoke when it burns, it gives less light. As the flame size increases the light given out would also be more. But if the kerosene starts giving smoke, the height of the flame has no meaning. So the higher the flame without smoke, the better. Smoke point is related to hydrogen content of the fuel. The higher the hydrogen content, the higher will be the smoke point. Paraffins contain highest hydrogen content for the same carbon number. So the smoke point of paraffins is highest. The specification of smoke point for kerosene in our country is 18 mm minimum. Aniline Point Aniline point is the minimum temperature at which equal volumes of sample and aniline are miscible. Aniline point gives the hydrocarbon nature of the oil. Aromatic hydrocarbons have lower aniline points and paraffinic hydrocarbons have higher aniline points. Naphthenic hydrocarbons have intermediate aniline points.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 30 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes Aniline point in combination with density /specific gravity/ __________________ API gravity gives a quick idea of some important properties __________________ like Diesel Index, Aniline-Gravity Product which are __________________ important properties for diesel and ATF. Aniline gravity __________________ product is an alternative to calorific value. __________________ Carbon Residue __________________ __________________ Every oil, when it burns, forms a carbon deposit which is __________________ very difficult to burn. This carbon deposits on burner tips __________________ chocking the orifices due to which the flow of oil stops and burner tip needs to be cleaned. If this carbon deposit is more, __________________ the burner tips have to be cleaned more frequently. Carbon residue test gives an indication of the amount of carbon that would form when the oil is pyrolysed and burned. There are two methods to determine carbon residue: 1. Ramsbottom Carbon Residue (RCR) 2. Conradson Carbon Residue (CCR) Vapor Pressure This is an indirect method of estimating most extreme low temperatures under which initial vaporisation can be expected to take place. It can be considered as a semi quantitative measure of the amount of most volatile material present in the product. It can also be used as a means of predicting the maximum pressures which may be experienced at fuel tank temperatures. Colour Two types of tests are applicable to petroleum products 1) Saybolt colour and 2) ASTM Color. The former is applicable to white oils like kerosene, naphtha, MTO etc and the other is applicable to diesel, vacuum distillates etc. The colour gives an indication of the degree of refining or contamination with foreign bodies.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 3 Specifications of Petroleum Products & Related Tests 31 BMCI (Bureau of Mines Correlation Index) Notes __________________ BMCI is an indication of predominant nature of __________________ Hydrocarbons in a product. __________________ All normal paraffins have BMCI zero or less than zero. __________________ A high BMCI indicates predominantly Aromatic nature. __________________ __________________ A low BMCI indicates predominantly paraffinic nature. __________________ Intermediate BMCI indicates mixtures of both and also __________________ naphthenic nature. __________________ __________________ BMCI more than 100 indicates presence of condensed rings. BMCI of some hydrocarbons Hydrocarbon BMCI N Paraffins 0 or < 0 Iso Paraffins < 15 Cyclohexane 50 Benzene 99 BMCI is a calculated value form density and 50% boiling point. It is defined as, BMCI – (48640 / K) + (473.7 * G) – 456.8 Where, o K = 50% Boiling Point in K 0 G = Specific Gravity @ 20 / 4o C There are graphical correlations between BMCI and Viscosity and Density also which are nearly equal to the calculated value. Bromine Number Bromine number is defined as the grams of bromine that react with 100 grams of the sample. Bromine number gives the olefinity of the sample.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 32 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes Olefins react with bromine giving additional products. Each __________________ double bond absorbs two atoms of bromine. __________________ Example: __________________ __________________ CH3CH2CH2CH2CH = CH2+Br2 CH3CH2CH2CH2CHBRCH2Br __________________ Benzene Content __________________ __________________ This test is applicable to motor gasoline. __________________ Benzene is carcinogenic (causes cancer). Its limit in MS is __________________ recognised by all countries. The specification for benzene in __________________ India is 5%v for general supplies and 1% v max for supplies to NCR. Density Petroleum products are liquids. They are sold on a volume basis but the custody transfers are effected on weight basis. Density is required for mass balance calculation and is also useful for several correlations which indicate the hydrocarbon nature and other properties. Some of such correlations are, BMCI, Kuop, VGC. Weathering Test This test is applicable to LPG. It indicates the amount of non vaporisable matter in LPG. Specifications of Petroleum Products LPG (IS 4796) Test Unit Specification Density kg / M3 Report o Volatility (95% Ev Temp) C +2 Max o Vapor Pressure @ 38 C kg / cm2 7 Max o Copper Corrosion @ 38 C 1 Max Sulphur %w 0.05 Max Odor -- Identifiable
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 3 Specifications of Petroleum Products & Related Tests 33 Motor Gasoline (IS 2796 - 2000) Activity 3 A Test Unit Method Requirement What are different Petroleum Products? Color -- Visual Orange Density @ 15 C o kg / M3 P:16 710 – 770 __________________ Distillation __________________ o Recover @ 70 C % v P : 18 10 – 45 o __________________ Recovery @ 100 C % v 40 – 70 Recovery @ 180 C % v o 90 min __________________ o Final Boiling Point C 215 max __________________ Research Octane Number P:27 88 min __________________ Anti Knock Index P:26 & P:27 84 min __________________ Existent Gum gm/M3 P:29 40 max (Solvent washed) __________________ Potential Gum gm/M3 p:147 50 max __________________ Sulphur %w P:34 0.1 max __________________ Lead as Pb gm/1 ASTM D 5059 0.013 Reid Vapor Pressure KPa P:39 35-60 VLI Summer Winter --- 750 max 950 max Benzene %v ASTMD 3606 5 max 1max for NCR Cu Corrosion P:15 1 o @ 50 C for 3 Hrs Water Tolerance Summer 10 Winter 0 Oxygenates % v ASTM D 4815-89 15 max NB: 1) MFA containing Phosphorus compounds should not be used 2) Potential Gum before doping MFA PC Naphtha Test Unit Method Requirement Appearance Visual Clear and Bright Color Visual Colourless Density @ 15 C kg/M3 P:16 To Report Distillation IBP C P:18 28 min FBP C 160 Total Paraffins %w ASTM D 5443 74 min Normal Paraffins %w ASTMD 5443 36 min Iso/Nor Paraffin Ratio 1.05 max n C6 %w To Report nC7 %w To Report Contd...
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 34 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Activity 3 B Aromatics %w 10 max What are the key specifications of Olefins %w P:23 1 max Motor Spirit, LPG, HSD, Petrochemical Naphtha, ATF? Total Sulphur ppm w P:34 B 100 – 250 How do these affect performance? Mercaptan Sulphur ppm w P:109 150 max __________________ Reid Vapor Pressure Kpa P:39 To Report __________________ @ 38ºC __________________ Chlorides ppm w ASTMD 4929 5 max __________________ Lead ppb w P:82 100 max Arsenic and Mercury ICP To Report __________________ __________________ Superior Kerosene (IS 1459 - 1974) __________________ Test Unit Method Requirement __________________ Acidity (Inorganic) mgKOH/gm P:2 Nil __________________ Burning Quality __________________ Char value mg/kg Oil P:5 20 max Bloom on chimney not darker than grey Color (Saybolt) Undyed Units P:14 +10 Dyed Blue Copper Corrosion @ 50 o C for 3 Hrs P:15 Not worse than 1 Density @ 15 o C kg/M3 P:16 To Report Distillation o Recovery @ 200 C %v P:18 20 min o Final Boiling Point C 300 max o Flash Point Abel C P:20 35 min Smoke Point mm P:31 18 min Total Sulphur %w P:34 0.25 max Aviation Turbine Fuel (IS 1571 - 1992) Test Unit Method Requirement Appearance -- Visual Bright, Free from solid matter and visually undissolved water. Acidity Total mg KOH/gm P:113 0.015 max Aromatics %v P:23 25 max Olefins %v P:23 5.0 max Total sulphur %w P:34B 0.30 max Mercaptan sulphur %w P:109 0.003 Contd...
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 3 Specifications of Petroleum Products & Related Tests 35 Distillation Notes 10 % v Recovered at degree C P:18 205 max __________________ 50 % v Recorded at degree C P:18 Report __________________ 90 % Recovered at degree C P:18 Report __________________ Final Boiling Point degree C P:18 300 max __________________ Flash Point degree C P:20B 38 min __________________ Density @ 15 C kg/M3 P:16 0.775 to 0.840 __________________ Freezing Point degree C P:11 Minus 47 max __________________ Kinematic Viscosity __________________ @ Minus 20 C cST P:25 8.0 max __________________ Aniline Gravity Product --- P:3 4800 __________________ Smoke point mm ISO 3014 25 min Naphthalenes %v ISO 3014 3.0 max Copper Corrosion % 100 degree C for 2 Hrs --- P:15 1 max Silver Corrosion @ 50 degree C for 4 Hours --- IP 227 1 max Thermal Stability Pressure Differential mm P:97 25 max Tube Rating Visual Visual 3 max No Peacock Or abnormal color deposits Existent Gum mg/100 ml P:29 7 max MSEP --- P:142 85 min Electrical Conductivity ps/M IP 274 50 to 450 Lubricity mm ASTMD 5001 Report High Speed Diesel (IS 1460 – 2000) Test Unit Method Requirement Acidity Inorganic mg KOH/Gm P:2 Nil Acidity Total mg KOH / Gm P:2 0.2 max Aah %w P:4 0.01 RCR %w P:8 0.3 (on 10 % residue) Cetane Number OR --- P:9 48 min Cetane Index --- ASTMD 4737 46 min Pour Point --- P:10 3 Winter Copper Corrosion @ 100 degree C for 3 Hrs - - - P;15 1 max Density @ 15 degree C kg/M3 P:16 820-860 Contd...
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 36 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes Distillation __________________ Recovery at 350 degree C % v P:18 85 min __________________ Recovery at 370 degree C % v P:18 95 min __________________ Flash Point degree C P:20 35 min __________________ Kin Viscosity @ 40 deg C cST P:25 2.0 to 5.0 __________________ Sediments %w P:30 0.05 __________________ Total Sulphur %w P:33 0.25 Water Content %v P:40 0.05 max __________________ CFPP deg C P:110 6 Winter __________________ 18 Summer __________________ Total Sediments mg/100 ml UOP 413 1.5 max __________________ Lubricity HFRR Scardia Micron at 60o C, 400 Proposed Light Diesel Oil (IS 1460 - 2000) Test Unit Method Requirement PSS Acidity Inorganic mg KOH/Gm P:2 Nil --- Ash %w P:4 0.02 max 0.005 max RCR on whole sample %w P:8 1.5 max 0.3 max Pour Point deg C P:10 12 Summer 0 max 21 Winter 0 max Copper Corrosion @ 100 deg C for 3 Hrs --- P:15 2 max 1b Flash Point (PMCC) deg C P:21 66 min 66 min Kin Vis @ 40 deg C cST P:25 2.5 to 15.7 2.5 to 5.0 Sediments %w P:30 0.1 Max 0.05 max Density @ 15 deg C kg / M3 P:16 Report 910 max Total Sulphur %w P:33 1.8 max 0.35 max Water content %v P:40 0.25 max 0.05 max Petroleum Coke (IS 8402 - 1994) Test Unit Method Requirement PSS Moisture as Received %w P: 132 10 max 8 max Moisture after Initial drying %w P: 132 2.0 max --- Ash on Dry basis %w P: 126 0.45 max 1.0 Max Volatile Matter %w P: 134 11 max 8 max Contd...
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 3 Specifications of Petroleum Products & Related Tests 37 Density (Dry) kg/ M3 P: 133 Report 560 min Notes Fixed Carbon __________________ (On Dry Basis) %w Calculation 85 min 88 min __________________ Total Sulphur %w P: 33 2.5 max 7.0 max __________________ Trace metals __________________ Silicon as Si ppm w UOP 389 Report 150 max __________________ Iron as Fe ppm w 150 max __________________ Vanadium as V ppm w 1600 max __________________ Nickel as Ni ppm w 400 max __________________ Hardgrove Grindability __________________ Index ASTMD 4097 50 MIN __________________ GCV Kcal/ Kg --- 8000 min…………. Properties of Petroleum Products and their Significance Gasoline Effect of Chemical Composition on Gasoline Quality Octane number is the most important property of motor gasoline. Composition of motor gasoline profoundly affects its performance in the engine and equally controls its behaviour under storage and handling.These are described below: Paraffins (Cn H2n+2) – Thermally and chemically most stable compounds. – Have poor octane number – Increasing the chain length reduces the octane number – Knock resistance increases with branching – Adding methyl groups (CH3) to the side chain in the central position increases the knock resistance Olefins (Cn H2n) – Oxidation and thermal stability is poor in general – More knock resistance than their corresponding saturated compounds.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 38 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes Cycloparaffins (CnH2n) __________________ – Poorer knock resistance than corresponding aromatics __________________ __________________ – Lengthening of side chain decreases knock resistance __________________ – Branching of side chain is beneficial. __________________ __________________ Aromatics (CnH2n-6CnH2n-12 etc) __________________ – Aromatics have excellent knock resistance qualities. __________________ __________________ Properties of Gasoline and Oxygenated Compounds __________________ Property Methanol Ethanol Isopropyl Tertiary MTBE Gasline Alcohol Butyl Alcohol Chem. CH30H C2H5OH C3H70H C4H90H C4H9OCH3 C8H15 (Av.) Formulae Mol. Wt. 32 46 60 74 88 111 Oxygen 50 35 27 22 18 0 Cont. % mass B.P.ºC 65 78.3 82.2 82.8 55 30-20 Stoichio- 6.4 9.0 10.3 11.1 11.7 14.6 Meteric A/F Lat. Heat of 3300 2600 2100 1700 900 800 Vap. Btu/Gal (11.8) (9.3) (7.5) (6.1) (3.2) (2.9) (J/lit) Net Heat 21 28 32 35 35 43 comb. MJ/Kg Solubi- ∞ ∞ ∞ ∞ 4.8 Trace Solubility in water, g/100g water RON 107 108 112 113 116 87-93 MON - - - - 101 82-87 Gasoline Properties Needed for Acceptable Performance Fuel Performance Required Property Controlled for Automotive Gasoline Handling and Storage Volatility Vapour Pressure Contamination (Water/Sediments/Gum) Copper Corrosion Combustion Octane Number Volatility/Distillation Range Gravity Engine Cleanliness Hydrocarbon Compostion Sulphur Existent Gum Oxidation Stability Combustion and Knock Before combustion, air and fuel is heated up in combustion chamber, there is an induction period before normal hot
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 3 Specifications of Petroleum Products & Related Tests 39 flame occurs. During this induction period, oxidation of fuel Notes takes place with the formation of intermediate products such __________________ as peroxides, aldehydes and peracids. Formation of __________________ peroxides, aldehydes and peracids prevents knock due to __________________ their ability to dissociate and promote such type of __________________ intermediate reactions. __________________ __________________ Knocking Tendency __________________ High Anti-knock Value: Aromatics, Isoparaffins (highly __________________ branched) __________________ Intermediate Anti-knock Value: Mixed parffins e.g. __________________ isoparaffins with little branching, Naphthenes. Low Anti-knock Value: Paraffins Combustion Chamber Deposits Deposits are formed by – Incomplete Combustion – Partial Oxidation – Cracking – Condensation and Polymerisation of fuel and lubricants – May contain nonvolatile reaction products of additives Deposits can lead to: – Pre-ignition Peak pressure and temperature will increase due to apparent increase in compression ratio and poor heat transfer due to heat insulation effect. – Loss of power due to reduction in volumetric efficiency – Exhaust valve corrosion – Spark plug fouling
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 40 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes Volatility __________________ __________________ Volatility of gasoline is its tendency to pass from liquid to vapour phase. Volatility influences: __________________ __________________ – Ease of starting __________________ – Rate of warm up and acceleration __________________ __________________ – Tendency to vapour lock __________________ – Carburettor icing __________________ __________________ – Crankase dilation – Fuel economy Ease of Starting For a cold engine start, enough gasoline in the intake air must be evaporated. Ease of starting depends on: y Fuel volatility y Engine design y Cranking speed y Engine oil viscosity Warm Up and Acceleration It depends on: 1. Fuel volatility and ambient temperature 2. Provision for thermostatical controlled hot spots. Warm up is mainly a cold weather problem. Vapour Lock and Percolation Vapour lock is a function of : 1. Volatility characteristics of fuel 2. Fuel requirement of engine at the moment 3. Ability of fuel pump to handle the vapour
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 3 Specifications of Petroleum Products & Related Tests 41 4. The temperature and pressure in the fuel system Notes __________________ 5. The temperature of ambient air, underbonet __________________ temperature and barometric pressure. __________________ Measurement of Volatility __________________ __________________ 1. ASTM D-86 Distillation __________________ Significant temperatures are __________________ – Initial boiling point __________________ __________________ – Temperature corresponding to 10% Vol. __________________ – Temperature corresponding to 50% Vol. – Temperature corresponding to 90% Vol. – FBP – Non-volatile residue left in the flask. 2. Reid vapour pressure (RVP) Controls the volatility due to lighter ends. TYPICAL VALUES OF VAPOUR PRESSURES (RVP) 2 K g /c m PSI KPa P ro p a n e 1 4 .1 200 1 3 8 2 .8 B u ta n e 5 .6 80 5 4 9 .2 M o to r G a s o lin e 0 .7 10 6 8 .6 3. Vapour lock index (VLI) 10 RVP+ E 70 Gives better indication of vapor locking. Carburetor Icing It occurs due to following: – Stoppage of the fuel flow due to clogging of the jetice – Formation of ice on the walls of carburetor ventenary which causes the engine to stall due to over-rich fuel/ air mixture
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 42 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Activity 3 C – High volatility of fuel How is gum formed in motor spirit, what is its impact and how is it – Cold and humid climate are favorable for icing. overcome? __________________ Remedial Measures __________________ – Control of fuel volatility __________________ – Providing heating of carburetor body or the intake air, __________________ particularly during warm up period __________________ __________________ – Providing greater throttle opening during starting __________________ – By incorporation of anti-icing agents __________________ l Anti-freeze type __________________ __________________ l Surface active agents Oxidation Stability Gum formation takes place in storage due to oxidation/ polymerisation reaction undergone by the unsaturated hydrocarbons and it accelerates at higher temperatures. Gum is a rubber like resinous material and is insoluble in later stage of formation. Sulphur and nitrogen compounds also take part in these reactions Gum formation is influenced by storage conditions, temperature, access of air and light, and catalysts particularly traces of copper. Impact of Gum Formation y May cause intake valve sticking due to deposition of Gum, and may lead to valve burning y May cause malfunctioning of carburetor float or impair the functioning of throttle y Deposits formed in the intake may restrict engine breathing and reduce the efficiency of hot spots resulting in increased warm up period y It can lead to increased sludge and varnish deposits in the engine.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 3 Specifications of Petroleum Products & Related Tests 43 Sulphur Compounds and Corrosiveness: Notes __________________ Most of the sulphur compounds are removed in the __________________ manufacturing processes. If these H2S and COS are mainly __________________ corrosive and RSH is distinctively unpleasant. __________________ Sulphur, on oxidation, forms oxides of sulphur which react __________________ with water to form sulphuric acid. __________________ A direct result of leakage of unburnt fuel can be corrosion of __________________ engine parts. __________________ __________________ Stringent specifications are required to be followed due to __________________ environmental considerations. Automotive industry requirement for meeting Euro III/ IV emission standards for Motor Gasoline. RON MON 89 79 to continue for old cars 91 81 to be widely available 93 83 to continue for high CR cars Benzene content 1% Max Aromatics 40% Max Olefins 25% Max Lead Content 0.005% Max Sulphur Content 0.05% Max Oxygen Content 2.70 Max Diesel Fuels BIS Grades of Diesel Fuels There are three grades of diesel: – High Speed Diesel (HSD) – Light Diesel Oil (LDO) – Marine Diesel (MD)
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 44 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes HSD Blending Components (Typical) __________________ B0ILING RANGE ºC CETANE NUMBER __________________ Heavy SR Naphtha 148-204 28-42 __________________ Kerosine 204-260 45-50 __________________ LT. SR Gas Oil 250-315 45-50 __________________ Heavy Gas Oil 315-350 50-55 LT. Cycle Oil 204-343 15-20 __________________ Hydro Cracker Go 204-343 50-60 __________________ Coker Kerosene 204-340 15-20 __________________ __________________ FUEL Performance Requirements __________________ Performance Property Control characteristics Handling & Storage - Volatility - Flash Points - Flow - Viscosity - Corrosive constituents - Water & sediments - Contaminants - Copper corrosion - Cloud/Pour pt. - CFPP Combustion - Ignition Delay - Cetane Number - Volatility - Distillation Range - Heat content - Gravity - Cloud & Pour Point Cleanliness During - Heavier constituents Carbon Residue on 10%, Bottom Ash Use Content, Sulphur Content, Stability - Metals Exhaust Emission Standards - Corrosive constituents Effect of Diesel Fuel Hydrocarbon Type Composition on its Quality Paraffins – Have the best combustion characteristics and highest cetane numbers – With molecular weight of n-parrafins, cetane number increases – Isoparaffins have lower cetane numbers than the paraffins of same carbon numbers. With branching cetane number is lowered. Olefins – Olefins have lower cetane numbers than paraffins of corresponding structures and follow similar rules of branching
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 3 Specifications of Petroleum Products & Related Tests 45 – Presence of olefins gives rise to poor oxidation Notes stability. __________________ __________________ Naphthenes __________________ – Naphthenes follow olefins in cetane quality but are a __________________ good deal higher than aromatics. __________________ __________________ Aromatics __________________ – Impart lowest cetane number and most important factor __________________ controlling the cetane number of cracked gas oil __________________ – Aromatics ring condensation and the side chain __________________ branching on rings that cause molecular configuration of lowest cetane numbers. Ignition Quality This is the most important property that controls combustion process. It is measured as a cetane number which is a measure of ignition delay and is controlled by – Fuel composition and characteristics – Engine design – Fuel and air inlet temperature – Degree of atomisation. As a result of abnormal ignition delay, large quantities of oil are gathered in the combustion chamber. Spontaneous burning and detonation of this surplus fuel in combustion chamber causes rough ignition which is termed as diesel knock or cetane knocking. Cetane Improver Additives Base Diesel Cetane No. 44 Additive dozes 1.5% Increase in CN Isoproyle Nitrate 17 n – Amyl Nitrate 23
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 46 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes Cyclohexyl Nitrate 22 __________________ Octyl Nitrate 19 __________________ __________________ Flow Properties __________________ __________________ Viscosity __________________ u Viscosity of diesel fuel has an effect on handling of the __________________ fuel by pump and injector system. __________________ u High viscosities can cause __________________ __________________ – Poor atomisation – Large droplets – High spray jet penetration u Low viscosity results in a spray which is too soft and thus does not penetrate sufficiently. As a result combustion is impaired and power economy is decreased. u Lubricating oil properties of such fuels are usually poor u HSD viscosity range is generally 2.0 to 5.0 cst. u Heavy distillates, when used as diesel fuel, are generally preheated. Cloud Point u Congealing wax settles out and blocks fuel system line and filters. u The temperature at which precipitation occurs depends on the composition and boiling range of the fuel. u Cloud point indicates the temperature at which waxes start precipitating. Cold Filter Plugging Point (CFPP) u Cloud point being a static test does not truly represent actual running conditions. u CFPP is defined as highest temperature expressed as a multiple of 1 o C at which the fuel when cooled
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 3 Specifications of Petroleum Products & Related Tests 47 under prescribed conditions will not flow through a Notes filter or requires more than 60 sec for 20 ml to pass __________________ through. __________________ __________________ Pour Point __________________ u Pour point gives a useful guide to the lowest __________________ temperature at which the fuel can be cooled with setting. __________________ __________________ Cleanliness in Use __________________ Carbon Residue __________________ __________________ u Gives some indication of coke forming / deposit forming tendencies in the engine. u Deposits are mainly carbonaceous matter, ash, resins etc. u Type of deposits is also an important factor. Hard abrasive deposits can do more harm than soft fluffy deposits. u The test can also be used to detect contamination by heavy residues. u Maintenance life and period of over-haul mainly depends on deposit control. Ash Content u Indicates the presence of small quantities of metallic soap or volatile porphyrines. u Unburned metallic constituents have abrasive action and cause wear by adversely affecting the nature of deposits. Water and Sediments u These may come into the fuel through contamination during storage and handling. u They can cause clogging of filters. u Sediments cause wear and create deposits both in the injection system and engine itself.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 48 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes Sediment and Gum Forming Reactions (Diesel Fuel __________________ Stability) __________________ 1. Oxidative Gum Reactions __________________ __________________ Alkenee + Oxygen ….. Gum __________________ Reaction time ….. Weeks to months __________________ 2. Acid – Base Reactions __________________ __________________ Organic acid + Basic Nitrogen …… Sediments __________________ Reaction Time …… Hours to weeks __________________ 3. Esterification reactions Aromatic Hydrocarbons + Hetrocylic Nitrogen + Benzothiols Multi-step Process …… Sediments Reaction Time ….. Weeks to months These are more predominant in diesel fuel instability. Corrosive Constituents Sulphur Content u Strict emission regulations require stringent sulphur specifications u Due to high sulphur, combustion products corrode and also contribute to deposit formation. u Low speed diesel engines can tolerate more sulphur, because – They are large in size and are stationary – They are high power output type – They run under relatively constant speed and load conditions – Their operating temperatures, cooling water and combustion zone temperatures tend to remain at
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 3 Specifications of Petroleum Products & Related Tests 49 an equilibrium rather than to fluctuate between Notes high and low. __________________ __________________ Tests carried out __________________ u Estimation of sulphur content __________________ __________________ u Copper strip corrosion test. __________________ Acid value __________________ __________________ u Total and Inorganic __________________ u Potentiometeric Acid/Base titration __________________ Residual Fuels Oils Changes in quality of fuel oils in Indian refineries are due to: u Frequent changes in crude quality and blend ratios u Intake of more of heavy crudes u Introduction of various secondary conversion processes for maximisation of middle distillates. Components of Residual Fuel Oils u Long residue u Short residue u Heavy cycle oil, clarified oil from FCC u Hydrocracker bottoms u Visbroken products u TAR from thermal conversion process u Slop Uses u Steam boilers u Industrial applications requiring heat u Gas turbines u Diesel engines
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 50 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Activity 3 D Summary of Fireside Problems Related to Fuel Quality Effect of metals in furnace oil? __________________ Problems Causes Solutions __________________ Plugging of fuel lines Oxidation of the fuel to Addition of inhibitors and strainer and burner tips produce acid and sludge sludge dispersants __________________ Fuel system corrosion Acidic, sulphur Application of corrosion __________________ compounds, water, sludge inhibitors __________________ High temperature fouling & Na, V in fuel form low - magnesium additives corrosion melting point sulphated __________________ ash - reduce excess air - combination of both __________________ __________________ Effect of Sulphur __________________ __________________ u Raises dew point of fuel gases u Increases formation of sulphur deposits in boiler passages, economiser, air–preheater and chimney u Reduces efficiency by reducing permissible temperature u Accelerates formation of gum and sediments during storage u Corrosion of process and plant equipment u Sulphur pick by product. Effect of Metals u Vanadium is a major metallic impurity in residual fuel oil. Causes corrosion in high temperature zone. u Sodium is recognised as a potential corrosion problem. u In combustion, Na converts to Na2O + Na2SO4 V converts to V2O5 + V2O4 ® Na2 V2O5, Na2 V2O4 5V2O5 (Low melting ash deposits) u Other ash deposits are SiO2, AI2O3, Fe2O3 NaAIO2 has high melting point (3272 oF). It causes metal spalling or breaking off of pieces of refractory due to its high thermal expansion.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 3 Specifications of Petroleum Products & Related Tests 51 Review Questions Notes __________________ 1. What is the significance of following tests and to what __________________ petroleum product these are related: __________________ - Flash point __________________ - Distillation __________________ __________________ - Smoke point __________________ - Octane number __________________ - Cetane number __________________ - Viscosity __________________ - Silver corrosion - BMCI - Weathering test - Copper corrosion - Vapour pressure 2. What specifications for Motor Spirit and HSD are related to environmental pollution? What are the limits for these specifications for Euro III / IV standards? 3. What strategies are being adopted to improve these specifications to desired ones from the present values? What would be the impact on cost of production? (Refer Bibliography) 4. What streams of Process Plants in a Refinery are utilised to produce HSD, MS, LPG and PC Naphtha? (Refer Unit 4 & Bibliography).
  • 53 Unit 4 Notes __________________ Integrated Refinery and __________________ __________________ Petrochemical Plants __________________ __________________ __________________ __________________ Objectives __________________ After studying the unit, the learner will be able to: __________________ __________________ y Understand the functioning of various process plants in a refinery and their integration with one another. y Give insight into the feeds composition of various process plants for production of finished products. y Give an overview of various off-site facilities in a Refinery. Now a days, to minimise processing cost and optimise product distribution, emphasis is laid on the following: 1. Economies of scale – Minimum 9-12 MMTPA refining capacity. 2. Refining and petrochemical plants are integrated. 3. Feedstock flexibility – To utilise low cost crudes. 4. Supply chain optimisation from crude to products, provides faster delivery and at lower cost. A typical integrated refinery and petrochemical plant set up is shown in attached block flow diagram. (Fig. 4.1) Crude is normally received by tankers or pipelines into crude tanks and allowed to settle for separation of water and sludge. Then it is taken to Crude Distillation Unit (CDU) which operates at atmospheric pressure for fractionation into Gas, LPG, Naphtha, ATF, Kerosene, MTO, Diesel, Jute Batching Oil (JBO) and Reduced Crude Oil (RCO). RCO is fractionated in Vacuum Distillation Unit (VDU) to get VGO and raw lube cuts. The raw streams from CDU are treated in Merox, Hydrotreatment, Reforming, Isomerisation and Fluid Catalytic Cracking plants to obtain components of
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 54 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes __________________ Naphtha __________________ Kerosen Kerosene __________________ Petro Gasolene __________________ Diesel __________________ LPG __________________ CRUDE CRUDE CDU/ TANKS VDU FCC Aro Paraxylene __________________ Propylene PP Polypropelene __________________ Coker MPP Power __________________ Sulfur __________________ FIGURE 4.1 INTEGRATED REFINERY AND PETROCHEMICAL BLOCK DIAGRAM finished saleable products. VGO is treated in FCCU to get LPG, Propylene, Petrochemical feedstocks and components for motor spirit and diesel. Raw lube cuts are treated for removal of aromatics and wax and are hydrotreated to get lube oil base stock. The short residue obtained from VDU fractionator bottom is partly treated in coker unit to get lighter value added products alongwith raw petroleum coke. Vacuum residue can also be treated to extract out Deasphalted Oil (DAO) and the residue left is asphalt. DAO is treated in aromatic extraction unit, dewaxing unit and hydrofinishing unit to obtain bright stock which is used for Lube oils and grease manufacture. Asphalt and vacuum residue can also be utilised for production of bitumen or as fuel for furnaces and boilers. From FCCU, olefins, propylene, various aromatics and naphthas are obtained which are used as raw materials for polypropylene and aromatic petrochemical plant. The Raw Petroleum Coke (RPC) is used for generation of power and calcined petroleum coke. Sulphur present in crude and various streams is converted to H 2S during processing. In Sulphur plant, it is converted to elemental sulphur which is sold as by-product. This also helps in environmental protection. Hydrogen plant is installed to produce hydrogen for meeting the requirement of various Hydrotreatment processes.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 4 Integrated Refinery and Petrochemical Plants 55 Crude Distillation Notes __________________ Brief process descriptions have been provided (please refer __________________ block flow diagram of CDU, VDU and SGU). This part has __________________ three main sections. __________________ 1. Desalting __________________ 2. Distillation-Atmospheric & Vacuum __________________ __________________ 3. Saturated Gas Concentration Unit (SGU) __________________ Lean Gas Other streams from other limits LPG to Marox __________________ S G C Naptha to __________________ Hydrotreater Atm LK/ATF F u osp Crude in Desalter heri r Flash n c HK Drum a Col. c e Diesel Preheat 1 Water in Brine Out Preheat 2 Preheat 3 JBO LVGO V Fumace a HVGO c. TO FCC Lube C distillates o l. Vacuum Residue to Belayed Coker/ Bitumen. FIGURE 4.2 BLOCK FLOW DIAGRAM OF CDU/VDU/SGU FIGURE 4.3 CRUDE AND VACCUM DISTILLATION UNIT IN A REFINERY
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 56 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes Desalting __________________ The crude oil is contaminated with various impurities– __________________ mainly salts of Ca, Mg, Na, CI, SO4, etc. These salts, however, __________________ in small proportions in crude, can cause severe corrosion in __________________ crude units, particularly in the overhead section. Several __________________ refineries worldwide have faced emergency shutdowns or __________________ have had to release hydrocarbons due to corrosion and __________________ material failures. Hence, it is important to remove the salts from crude prior to distillation. The desalters are designed __________________ for 99% salt removal and reach less than 1 ptb (part per __________________ thousand barrels) in desalted crude. __________________ Crude oil received from tank farm is heated from 30 to 140- 150ºC in cold preheat trains. This is done by recovering heat from outgoing products streams from the unit. This prepares crude for efficient desalting. Then it is passed through a desalter after being mixed with de-emulsifier and water thru a mixer valve. In the desalter, crude passes through high electric field. The salt dissolved in water settles at the bottom as brine and desalted crude with less than one parts per thousand barrel comes out from the top of the vessel. Separation of water containing salt is enhanced by de- emulsifier. Desalters remove salts, sludge and mud from crude to avoid corrosion and fouling in exchangers columns and downstream equipment. Distillation – Atmospheric & Vacuum The desalted crude is then heated from 140º to 190º C at 25 Kg/a2 pressure by heating with a heavier hot stream. Then it is taken to the flash drum. From the top we get lighter components which directly go to the crude column. The flashed crude is passed through hot preheat exchangers and further heated from 190°C to 250–260°C. The purpose of hot preheat train is to recover heat from pump arounds to reduce furnace duty. Furnace provides required heat for fractionation in atmospheric column and crude is heated upto 385°C. The heated crude is fractionated in atmospheric distillation column of CDU. The fractions below 165°C are withdrawn as column overheads and sent to SGU. Here mainly gases, LPG and FRN are separated. Heavies boiling at more than
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 4 Integrated Refinery and Petrochemical Plants 57 386º C are reheated under vacuum condition (to avoid Notes cracking) and fractionated in vacuum column of VDU. __________________ __________________ Besides the straight run products such as LPG, Naphtha, LK, HK and Diesel, the other distillation products are __________________ intermediates viz. (1) Gas Oil (HAGO+LVGO+HVGO) which __________________ become feedstock for FCC after treatment in VGOHT and __________________ (2) VR which becomes feedstock for delayed coker. The LPG __________________ is sent to LPG Merox unit for treatment before sending to __________________ RTF. The FRN is directly sent to the HNUU in the aromatics __________________ complex. The Light Kero (LK) fraction is routed as SKO to __________________ RTF directly or via Kero Merox unit as ATF. The Heavy Kero (HK) fraction is blended with diesel fraction. The diesel __________________ fractions can be routed to DHT or RTF as required. Saturated Gas Concentration (SGU) The overhead liquid and gases from CDU, reformer and hydrotreaters of petro-chemical complex are passed through this plant to separate into following fractions: 1. Gases (C 1+C 2 ) for burning into furnaces or as petrochemical feedstock after H2S is removed in Amine Treating Unit. 2. LPG (C 3+C 4) for domestic and industrial use after removal of Mercaptanes in Merox Unit. 3. Naptha (C 5 to 165ºC) for sending to fertilizer or petrochemicals plants as feedstock. The typical streams obtained from crude oil by Atmospheric and Vacuum distillation are given in the following table: % of crude input Cut range deg C Fuel Gas 0.01 to 0.03% < C2s LPG 1.0 to 1.5% C3–C4s FRN 11 to 14% C5s to 16s LK / ATF 10 to 11% 165 – 227 HK 6 to 7% 227 – 270 Diesel 16 to 17% 270 – 370 HAGO 2.5 to 3.0% 370 – 392 RCO (Atm. Residue) <392 LVGO 2.5 to 3.5% HVGO 21 to 22% VR 23 to 26%
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 58 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes Product specifications and significance of the same is __________________ given in Unit 3 __________________ Operating issues which need attention are: __________________ 1. Crude mix and product yield pattern __________________ __________________ 2. Corrosion impact on various equipment should be __________________ known. __________________ 3. Health of equipment and run length of unit is vital. __________________ 4. Operating parameters such as pressure, temperature, __________________ flows. __________________ 5. Quality control of crude and products. 6. Health, safety and environment (HSE) aspects. 7. Energy conservation 8. knowledge and skills of operating crews. Diesel Hydro-Treatment The purpose of diesel hydrotreating unit is to: u Remove sulphur and nitrogen u Convert olefins/aromatics to saturated compounds. u Remove contaminants like oxygenates and organomettalic compounds. The catalysts used in this plant are oxides of Ni and Mo/Co & Mo impregnated on alumina base. Salient Features u 98% desulphurisation and 70% denitrification (VGO hydrotreater). u Produce low sulphur, colour stable diesel. u Reduce aromatics and nitrogen in diesel. u Improve Diesel cetane no. The feed to the unit consists of a mixture of SR diesel and heavy kerosene from the Crude Unit, light coker
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 4 Integrated Refinery and Petrochemical Plants 59 gas oil, HCO from the Delayed Coking Unit and LCO from Notes FCCU __________________ Diesel Hydrotreater __________________ __________________ Make up H2 __________________ Offgas to Ovhd. SGCU condensor __________________ Recycle gas __________________ Diesel __________________ __________________ Diesel VGO VGO __________________ Product LN separator __________________ LN Stripper Hydrotreater To waste water system FIGURE 4.4 HYDROTREATER BLOCK-FLOW DIAGRAM Brief Description of the diesel hydro-treater follows. The feed is pumped through cold and hot feed-reactor effluent exchangers and then with recycled gas streams through the combined feed heater. The combined feed heater heats the feed up to the reactor inlet temperature. The reactor consists of one vessel with two beds of catalysts, consisting of one inert and three different types of catalysts. Recycled gas is added as a quench between the beds to quench the top bed heat of reaction. The reactor effluent is cooled through a series of heat exchangers where it, in turn, heats up the fresh feed, the stripper feed, the recycled gas and then provides heat for generation of HP, MP and LP steam. A wash water stream is then injected into the reactor effluent before final cooling in the air-product condenser. From the product condenser, the reactor effluent enters the separator. The separator is a horizontal vessel with a water boot that separates the recycled gas from the stripper feed and the wash water from the stripper feed. The recycle gas goes through a recycled gas water cooler and knockout drum to remove heavier hydrocarbon components before entering the
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 60 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes recycled gas scrubber. This scrubber is used to remove H2S __________________ from the recycled gas by bringing it in contact with a liquid __________________ stream of lean amine. The top of the vessel contains a water __________________ wash section to pick up any entrained amine. The recycled __________________ gas exits from the top of the recycle gas scrubber, and is __________________ then mixed with makeup gas hydrogen before entering the __________________ recycle gas compressor. The stripper feed is heated in a __________________ series of exchangers where it in turn cools the stripper __________________ bottoms, reactor effluent, before entering the stripper __________________ column. __________________ The stripper is used to remove H2S from the diesel product, and also to separate unstabilised naphtha from the diesel product. Both the net off gas and the unstabilised naphtha liquid that are produced are routed to the Saturated Gas Concentration Unit. The stripper bottom is cooled through a series of exchangers, then further cooled by air and water before entering the diesel product coalescer and the salt drier which removes water prior to routing to the diesel product blending system. VGO Hydro-treatment This is similar to diesel hydro-treater and is used for preparing feed for FCC. FIGURE 4.5 HYDRO-TREATER/ HYDRO-CRACKER IN A REFINERY
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 4 Integrated Refinery and Petrochemical Plants 61 Hydrogen Production and Management Notes __________________ Hydrogen Production Plant __________________ Hydrogen is produced commercially using following __________________ technologies: __________________ __________________ (i) Partial oxidisation __________________ (ii) Coal gasification __________________ __________________ (iii) Electrolysis of water __________________ (iv) Steam hydrocarbon reforming __________________ (v) Platforming – as a by-product. Refer hydrogen plant block flow diagram Steam HP BFW HP steam export Recycle H2 Generator Refinery Product fuel gas Feed gas Feed Steam H2 Shift & gas Gas compr. purification reformer cooling purification Natural gas LPG Waste gas Main pumping section Refinery general fuel gas Naphtha (future) FIGURE 4.6 HYDROGEN PLANT BLOCK FLOW DIAGRAM Hydrogen Feed Feed for hydrogen production plant — (i) Refinery fuel gas, (ii) saturated LPG, (iii) Natural gas, (iv) Light Naphtha. Process Description Feed (Refinery Fuel Gas, or Natural Gas or LPG or Hydro- treated Light Naphtha) is first mixed with recycle hydrogen and passed through pre-treatment section. The function of pre-treatment section is to remove sulphur in feed by hydrogenation, in the form of H2S, and removal of chloride by sodium aluminate, the catalyst used is CoMo or NaMo. H2S is absorbed in Zno bed.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 62 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes If sulphur is <200 ppm, then single stage pre-treatment is __________________ adopted. For sulphur >200 ppm, double stage pre-treatment __________________ is used. __________________ The De-sulphurised feed is pre-heated with steam and __________________ passed through Nickle Catalyst packed in Vertical narrow __________________ tubes mounted in the reformer furnance. This process is __________________ endothermic and heat is supplied by fuel firing. Following __________________ reactions take place: __________________ __________________ Steam Reforming __________________ CH4 + H2O l 3H2 + CO CO + H2O l H2 + CO2 Water Gas Shift CO + H2O l H2 + CO2 Steam is added in excess to promote above reactions. Hydrogen gas produced is purified by pressure swing adsorption (PSA) method. PSA Cycle One PSA cycle is built up of 2 basic phases: Adsorption and Regeneration Regeneration of PSA Bed The regeneration phase is a chain of sub-phases consisting of: l High to low pressure transition: Expansion l Provide purge and dump l Purging at low pressure l Low to high pressure transition back to adsorption pressure: Repressurization.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 4 Integrated Refinery and Petrochemical Plants 63 Hydrogen Management Notes __________________ Hydrogen gas in the refinery comes from __________________ (i) Hydrogen production plant – as described above __________________ __________________ (ii) Catalytic reformers __________________ - in the refinery __________________ - in the integrated petro-chemical plant __________________ __________________ The hydrogen from both the sources is supplied to various __________________ consumers like hydro-treatment plants etc. through high __________________ pressure compressors and the excess gas is led to refinery fuel gas system. Need of hydrogen is increasing day after day for treating the products like motor spirit, HSD, fuel oils and feeds for FCC and other plants for bringing down sulphur. Merox (Mercaptan Oxidation) Treatment Process Description Merox is the abbreviation of Mercaptan Oxidation. In this process mercaptan is separated from hydrocarbon by washing with caustic solution. The separated merceptan is oxidised into disulfide form which can be disposed of in slop stream. Organic sulphur from LPG, ATF/Kerosene and Gasoline are removed by this process. Hydrogen Sulfide (H2S) from LPG is removed by extraction with regenerated lean Amine in Amine Treating Unit (A TU). Treated LPG is passed through reactor and mixed with caustic solution containing merox catalyst. Then it passes through extractor to remove mercaptan. Then, it is washed with water to remove caustic. Treated sweet LPG free of H2S and Mercaptan is sent to storage. In case of ATF/Kerosene and Gasoline treatment, first it is mixed with caustic, air and catalyst and then passed to reactor to convert mercaptanes to Disulfides, which is separated from caustic and product in caustic sulphur. Caustic in recycled. Sweetened product is stored in intermediate tanks before blending into finished product.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 64 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes Following reactions take place __________________ Mercaptan gets converted into disulfides __________________ __________________ 4RSH + O2 2RSSR + 2H2O __________________ Caustic Regeneration __________________ RSH + NaOH NaSR+ H2O __________________ (oil phase) Aqueous (Sodium Mercaptide soluble in __________________ phase Aqueous phase) __________________ Catalyst __________________ 4NaSR+02+2H2O 2RSSR+4NaOH __________________ (Aqueous Phase) 45ºC (oil Phase) The purpose of caustic in Merox process is: u To transfer the mercaptane, or the thiol portion of the mercaptane, to the aqueous phase. u To supply the alkaline environment needed for the reaction to proceed in the desired direction. FIGURE 4.7 MEROX TREATMENT PROCESS BLOCK FLOW DIAGRAM This process is used for treating LPG, Gasoline and ATF. Sulphur Recovery Plant The objective of sulphur recovery plant is to convert H2S to elemental sulphur.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 4 Integrated Refinery and Petrochemical Plants 65 Sulphur recovery is required because of: Notes __________________ l Increasing demand for environmental friendly fuels. __________________ l Increased used of high sulphur and heavier crudes in __________________ future. __________________ l Tightening of emission standards by government/ __________________ Regulatory bodies. __________________ Salient features of sulphur plant are: __________________ __________________ l Minimum sulphur recovery level of 98.7% __________________ l Ammonia destruction capability __________________ l Turndown capability 25% Process Description Refer sulphur plant block flow diagram (Figure 4..8) Acid gasses from Amin Recovery Unit (ARU) and sour gasses from sour water stripper are heated in pre-treater and burnt in presence of regulated quantity of air from CLAUS Air Blower in CLAUS Reaction Funance. The product from claus reaction funance is passed thru 1st and 2nd pass condensers. . Acid gases from ARU Thermal reactor Claus reactor CBA reactor Air Condenser 1 Condenser 2 Condenser 3 To tail gas incinerato Sour gases from WWSU Liquid sulfur To sulphur degassing pit granulation unit Air FIGURE 4.8 SULPHUR PLANT BLOCK FLOW DIAGRAM The sulphur condensed is routed to Liquid Sulphur Degassing Pit. The unreacted vapour is passed thru claus reactor. The vapour from the claus reactor outlet is passed
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 66 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes thru 1st and 2nd pass condensers. The condensed sulphur is __________________ taken to Liquid Sulphur Degassing Pit. The uncondensed __________________ vapour is passed through Cold Bed Adsorption (CBA) __________________ Reactors 1st and 2nd passes. The outlet vapour is passed __________________ thru 1st and 2nd pass of CBA condenser. The condensed sulphur is routed to liquid sulphur degassing pit and the __________________ remaining gases are taken to tail gas incinerator for burning __________________ and releasing thru high stack. Sulphur after Degassing is __________________ taken to granulation unit from where it goes for despatch to __________________ market. The off-gases from sulphur degassing pit is recycled __________________ to CBA section for recovery of sulphur. __________________ What is Claus Reaction? “When two molecules of Hydrogen Sulphide (H2S) react with one molecule of Sulphur Dioxide (SO 2) to give elemental sulphur in the presence of Alumina Catalyst, the reaction is called Claus Reaction” 2H2S + SO2 3/nSn + 2H2O n=No. of atoms in Sulphur molecule. u 1/3rd of total H2S in feed gas is burned to SO2, this SO2 reacts with remaining H2S to give elemental Sulphur in Claus Reactor H2S+3/20 2àSO2+H2O 2H2S + SO2à3/n Sn+2H2O Overall Reaction 3H2S + 3/2 O2à3/nSn + 3H2O Process Variables Air to Acid Gas Ratio H2S/SO2 Ratio = 2:1 u Claus Reactor Outlet Temp 344ºC Incinerator Temperature 650+ –50ºC Amine Treating Unit (ATU) The purpose of this process unit is to remove H2S from fuel gases to meet environmental requirements.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 4 Integrated Refinery and Petrochemical Plants 67 Process Description Notes __________________ Refer figure 4.9 simplified block flow diagram __________________ The fuel gas containing H2S is introduced in Middle section __________________ of Amine Absorber Column where Lean Methyl Diethanol is __________________ introduced near top section. By counter current flow H2S is __________________ absorbed in Amine and sweet fuel gas (FG) free of H2S comes __________________ out from column top. The rich Amine from bottom of the __________________ absorber column is taken to Flash Drum where any fuel gas carried over is separated out. The rich Amine is then pumped __________________ through heater where it is heated by the hot lean amine __________________ stream coming from bottom of Amine stripper. In the __________________ stripper, Amine Acid Gas from top of the column is routed to sulphur recovery plant along with sour gases from other process units. The lean Amine from bottom of the stripper exchanges heat with Rich Amine and then pumped to storage tank through cooler for recycling to Amine Absorber. Absorption Sweet FG Section Lean Amine Regeneration Abs Stpr Section FG Lean Amine Header Rich Amine Header Amine Storage Section FIGURE 4.9 SIMPLIFIED BLOCK DIAGRAM – ATU Process Chemistry The circulating amine is 35% MDEA solution, Hydrogen sulfide H2S OR HSH is a weak acid and ionizes in water to form hydrogen ions and sulfide ions. HSH H+ + SH–
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 68 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes Ethanol amines or weak bases ionize in water to form amine __________________ as hydroxyl ions __________________ (CH 2OHCH 2)2NCH 3+H 20 CH2OHCH2)2NHCH3+OH __________________ __________________ When H2S dissolves into the solution containing the amine __________________ ions, it will react to form a weakly bonded salt of the acid and the base. __________________ __________________ (CH2OHCH 2)2 NCH 3+SH (CH2OHCH2)2NSCH3 __________________ The sulfide ion is absorbed by the amine solution. Overall __________________ __________________ (CH 2OHCH 2) 2NCH 3+H 2S (CH2OHCH2)2NSCH3 Delayed Coking Coker Unit The purpose of coking unit is to produce valuable distillates and Petroleum coke (by-product) by upgrading heavy residual stocks from vacuum distillation and other process units generating heavy stock. This unit is also known as delayed coker. Slops from various other process units which do not find proper home can also be processed in coker to get valuable products. The feed to this unit is subjected to severe thermal cracking thereby producing refinery fuel gas, coker gasoline, coker kerosene, coker gas oil, coker furnace oil, residual furnace oil and coke. Process Description Refer block flow diagram of coker Feed is preheated by exchanging heat with hot streams. Thereafter, it is heated to 250ºC in convection section of the furnace before it enters the bottom section of fractionator column. The hot cracked hydrocarbon vapours from coke chambers top via a separator enters the zone of above- mentioned fractionator column. The heavy hydrocarbon fractions in these vapours condense in lower section of the column and are withdrawn from bottom along with primary feed by secondary feed pump.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 4 Integrated Refinery and Petrochemical Plants 69 Heavy cycle gas oil Notes LLP Flare Light cycle gas oil To HNUU __________________ HP flare To LNUU __________________ Vacuum Residue tank Unsat gas Unsat __________________ conc. unit LPG To LPG Coker Merox unit spheres __________________ FG __________________ distribution To flare system __________________ Coker consumption To light slop oil tank __________________ FO Rich tank To heavy slop oil tank __________________ amine Lean amine __________________ Amine treating __________________ Coke handling To ETP system FIGURE 4.10 COKER BLOCK FLOW DIAGRAM The secondary feed is heated in the remaining part of the convection section and full radiation section of the furnace to around 500ºC and enters the coke chambers where final cracking takes place. The vapours from top of the coke chambers is quenched with cold vacuum distillates before it enters the separator. The liquid product accumulated at separator bottom is pumped out as Residual Fuel Oil (RFO). The vapour is routed to bottom of fractionator as mentioned earlier. From the fractionator, products withdrawn are Light Kerosene (LK), Heavy Kerosene (HK), gas oil and coking fuel oil (CFO). Fractionator vapour top is condensed in over head condenser to produce gas and coker gasoline and coker naphtha (light coker naphtha and heavy coker naphtha). The petroleum coke is accumulated in coke-chamber, is cooled by steam and water and thereafter removed by hydraulic de-coking method which cuts the hard coke with high pressure water jets. The coke is removed by grab crane. After crushing and sizing, it is transported to store yard or sent to coke calcination plant. Facilities are also provided in the plant to produce LPG and release fuel gases to fuel gas system.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 70 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes Advantages of Delayed Coker __________________ u Minimum investment for given value addition __________________ u Zero fuel oil generation __________________ __________________ u Coke can be used as fuel for power plant. __________________ u No catalyst cost. __________________ u Capability to process refinery slops and sludge. __________________ __________________ Mechanism of Coking __________________ Cracking is a phenomenon by which large oil molecules are __________________ thermally decomposed into smaller lower-boiling molecules: at the same time some of these molecules, which are reactive, combine with one another to give even larger molecules than those in the original stock. The more stable molecules leave the system as cracked Naphta, Kero, Diesel (LCGO), Gas oil (HCGO) etc. and the reactive once polymerise, forming cracked fuel oil and coke. Fluidised Catalytic Cracking (FCC) Fluid Catalytic Cracking has developed into a major upgrading process in the oil refining industry for conversion of heavy fuel oil into more valuable products ranging from light olefins to LPG, naphtha and middle distillates. The attractiveness of FCC process is to its flexibility to process wide range of feedstocks from a variety of crudes and its favourable economics of operation. The objective is to maximise Olefins, LPG, C7 – C9 aromatics, high throughput and minimise LCO and bottoms. Hot regenerated catalyst is mixed at the bottom of reactor with raw feed and steam. After pre-acceleration, it is brought in to contact with the staged feeds supplied as finely atomised droplets. Feed instantaneously vaporises and travels up the riser with the catalyst where conversion reaction takes place. At the top of reactor, the vapour is disengaged from catalyst. The vapour is sent to main fractionating column. In this column, mainly LPG, Gasoline, middle distillates and decanted oil are obtained. The spent catalyst is steam stripped to remove hydrocarbon vapour and then sent to two stage regenerators for burning coke before it is recycled to reactor alongwith makeup catalyst to reactor.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 4 Integrated Refinery and Petrochemical Plants 71 Air is injected in catalyst regenerator for burning coke. Water Notes generated in the system leaves with flue gas from Power __________________ Recovery Train. Flue gases are sent to CO boiler and __________________ thereafter to a clean up system to remove particulates, SOx __________________ and NOx. ZSM additive is added to catalyst to increase LPG __________________ yield. __________________ Residues are also used as feedstock in RFCC. __________________ FCC __________________ __________________ __________________ __________________ FIGURE 4.11 FCC UNIT BLOCK FLOW DIAGRAM Petrochemical Process Plants Aromatics Plant The aromatics complex is a fully integrated facility for the production of paraxylene and orthoxylene, comprising of platformer primarily to produce feed for main plants. Aromatics complex processes special cut naptha to produce paraxylene and orthoxylene as the major products and some other by-products which include Benzene, Light Reformate, LPG, H2, Fuel Gas and heavies. The Paraxylene plant consists of the following units. (Refer figure 4.12 Aromatics Complex Block Diagram Flow). Heavy Naphtha Unionfining Unit (HNUU) The function of this hydrotreating unit is to treat the feed naphtha and remove impurities like heavy metals, sulfur,
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 72 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes nitrogen and olefins, which are poison for Platformer __________________ catalyst. __________________ Platformer Unit __________________ __________________ The platformer unit processes hydrotreated naphtha from __________________ the Heavy Naptha Unifining unit, stripper column bottoms, __________________ for the production of aromatics for downstream unit __________________ processing and separation. Major reactions taking place in platforming unit are as follows: __________________ __________________ 1. Dehydrogenation of naphthenes __________________ 2. Hydrocracking of paraffins 3. Isomerisation 4. Dehydrocyclisation of paraffins The spent catalyst is regenerated continuously in situ, which takes place in Cyclemax CCR. Xylene Fractionation Unit Xylene fractionation unit includes a xylene column and associated equipments to fractionate “Isomar” Deheptaniser bottoms and “Tatoray” Toluene column bottoms into an overhead product that is suitable as feedstock to the Parex process unit. The column is designed to both recover Orthoxylene into the bottom product or to minimise the loss of Orthoxylene into the bottom products Xylene rich overhead vapor are used as heating medium in Raffinate & Extract . Column Reboilers & also to generate MP Steam. Orthoxylene Fractionation Unit This unit includes an orthoxylene column and associated equipments for the production of a high purity orthoxylene product and a heavy aromatic column and associated equipments for the production of a C9-C1O aromatic overhead stream to be used as feed to the “Tatoray unit”, a sidecut stream with a 215°C endpoint for use as a gasoline blending component and a heavy aromatic bottom stream to be used as fuel oil.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 4 Integrated Refinery and Petrochemical Plants 73 Parex Process Unit Notes __________________ The process is selective adsorption of Paraxylene (PX) __________________ on molecular sieve and subsequent desorption of PX by __________________ a suitable desorbent. The molecular sieve is basically __________________ Y type zeolite (alumina silica) which preferentially adsorbs PX. __________________ __________________ Toulene column bottoms and C8 isomerates from Isomar __________________ section are fed to the xylene fractionation column. The __________________ overhead product of the xylene columns are feed to the parex __________________ unit. __________________ Feed and desorbent goes to the Parex adsorbent chambers via rotary valve. PX gets adsorbed on the molecular sieve and subsequently desorbed. Two streams come out of the chambers known as raffinate stream and extract stream. Raffinate stream is fed to the raffinate column. Its side cut product which is mixed xylenes lean in paraxylene, is fed to isomer unit while the bottom product desorbent is recycled back to Parex adsorbent chambers. The extract stream consist of PX, Toluene and Desorbent. PX and Toluene are separated as overhead products in extract column (feed to finishing column) while the bottom product Desorbent is recycled to Parex absorbent chambers. PX and Toluene are separated in a finishing column. Paraxylene is withdrawn from bottom and overhead product Toluene is recycled back to Tatoray unit. Isomer is a catalytic isomerisation process to efficiently convert a mixture of C8 aromatics to a near equilibrium mix that favours PX and OX production from metaxylene and ethyl benzene. The Tatoray unit includes reformer splitter column, two parallel reactor trans, stripper, benzene are toluene column. Objective of the units is to maximise xylene production by transalkylation of C7 and C9 aromatics.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 74 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes __________________ __________________ __________________ __________________ FIGURE 4.12 AROMATCS COMPLEX BLOCK FLOW DIAGRAM __________________ __________________ __________________ __________________ __________________ __________________ Polypropylene It is designed to produce homo, random and impact copolymer. The main raw materials are propylene and hydrogen. (Refer Figure 4.13 Propylene Block Flow Diagram) The plant consists of: 1. Purification Section: For propylene “to remove impurities like Sulphur, CO, CO 2 , O 2 ' purification section for hydrogen and nitrogen gas before supplying them to reaction area. Impurities like CO, CO2 from H2 and O2 from N2 are removed.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 4 Integrated Refinery and Petrochemical Plants 75 Notes __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ FIGURE 4.13 POLYPROPYLENE BLOCK FLOW DIAGRAM 2. Reaction Section: Here polymerisation reaction of purified propylene takes place in fluidised bed reactor in the presence of slurry catalyst (TiC14, supported on MgCl2 in slurry form in mineral oil); co-catalyst Triethyl Aluminium, purified hydrogen and selectivity control agent Peraethoxy Ethyl Benzoate or N-Proypl Trimethoxy Silane in the reactor. 3. Pelleting Section: Polypropylene (PP) resin is transferred from reactor to product receiver using dense phase conveying system. The conveying gas which is a mix of hydrocarbon and nitrogen is separated from the resin in disengaging section of product receiver. The unreacted monomers are purged with light recycles and sent for recovery to vent recovery system. PP requires the incorporation of a variety of additives to aid its processing and achieve the end use properties. The polymer is fed into the melt pump to develop necessary pressure for extrusion through the die plate. The Polymer strands are palletised in underwater pelletiser and the pellets are carried by pellet water system to agglomerate remover where chunks and clusters are removed. The pellets are then dried, classified and conveyed to the blending silos from where they are bagged.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 76 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes 4. Vent Recovery Section: This system is designed to __________________ recover monomer, polymer and nitrogen. All waste __________________ flammable gases are vented to the HP or LP flare header, __________________ which are passed through knockout pot and burnt at __________________ flare stack burning tip. __________________ Typical Refinery and Petrochemicals complex – Product __________________ Pattern __________________ Propylene 2.0% __________________ LPG 7.0% __________________ Gasoline 8.0% __________________ Naphtha 8.5% Reformate (Petrochemicals feed) 9.5% HSD/SK/ATF 48.0% Coke 8.0% Sulphur 1.5% Fuel and Loss 7.5% Typical Refinery Product Pattern Input % of Crude Crude Oil 100.0 Products LPG 2.1 Net Naphtha 5.0 MS 11.2 Others -- Light Distillates 18.3 ATF 2.6 SKO 9.0 HSD 35.1 LDO 16.0 Others 1.1 Middle Distillates 63.7 LSHS for sale 3.3 Others 7.9 Heavy Ends 11.6 Total Prods 93.6 Gross F&L 6.8 Total 100.0
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 4 Integrated Refinery and Petrochemical Plants 77 Typical Yield Pattern of FCC Notes __________________ Feed: 100% __________________ Low ‘S’ VGO 53.7 __________________ CGO 20.3 __________________ DWO 9.0 __________________ VR 17.0 __________________ Output __________________ Gas 3.9 __________________ H2S 0.5 __________________ LPG 12.7 __________________ Gasoline 12.5 TCO 53.4 CLO 8.6 Coke 7.9 Loss 0.5 Total 100.0 Typical Yield Pattern of Delayed Coking Unit Input = RCO 100% Output: LPG 2.5 Cok. Gasoline 4.5 Cok. Kero-I (LK) 22.5 Cok. Kero-II (HK) -- Cok. Gas Oil (CGO) 24.5 CFO 14.5 RFO 6.5 RPC 16.3 GAS 6.3 Loss 2.4 Total 100.0
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 78 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes Typical Yield Pattern of Hydro-treater __________________ Input: __________________ VGO 100.0 __________________ H2 2.0 __________________ Total 102.0 __________________ Output __________________ H2S 1.2 __________________ GAS 1.3 __________________ LPG 3.0 __________________ LT. Naphtha 11.5 __________________ Hy. Naphtha 4.0 SKO/ATF 27.0 HSD 43.8 Bottoms 10.0 Loss 0.2 Total 102.0 Offsite Facilities and its Management In a Refinery, 80% to 90% area is covered by offsite facilities. Traditionally, more attention used to be given to process units. However, with Refinery margin shrinking, stringent safety, Health and Environmental stipulations, and increased customer expectations, now more and more emphasis is given for improved profitability through: l Improved operations l Advanced process control system l Good inventory management l Optimisation of storage facilities & other offsites. Major offsite functions in a Refinery are: 1. Crude oil receipt Normally crude oil is received in land locked refineries through crude pipelines from the production source. Before bringing the crude from oil fields, gas, water and sludge are removed by settling and processing through desalters. In
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 4 Integrated Refinery and Petrochemical Plants 79 coastal refineries, crude oil is received through tankers. Notes Depending on the capacity of the refinery, crude tankage __________________ available, draft available at receiving oil jetty, size of crude __________________ oil tanker varies from small to very large. Quantity of crude __________________ received in the refinery is monitored by measuring dip of __________________ receiving tank and flow metre readings installed on crude __________________ pipeline. India imports almost 70% of its crude oil __________________ requirement. Due to strategic reasons, crude oil storage is __________________ being increased from 15 days to 45 days of the refinery capacity. __________________ __________________ 2. Crude preparation for feeding to distillation units __________________ Though in the oil field, major quantity of sludge, water and associated salts are removed before bringing crude to refineries, yet some quantities of sludge and water still are received in the refinery tanks. This is removed by allowing the crude to settle in the tanks and draining from bottom to the effluent treatment system. The final removal of water associated with salts and sludge takes place in desalter in the crude distillation unit. Unless crude preparation is done properly, the unit performance will be affected adversely due to fouling of pipes, exchangers, furnace tube corrosion, corrosion of various equipments and upsets in plant operation. This will also lead to increased fuel consumption and loss in the units. 3. Receiving rundown streams from various units From crude distillation unit and other secondary units, we get various products streams, most of which are to be treated in secondary processing units and blended in required proportion to produce finished products which are then dispatched to the market. Except LPG and Naptha, all other products are blends of various streams from different units. Depending on the capacity of refinery, number of products marketed, types of crude oil processed, complexity of the refinery, the tankages provided for receipt of rundown streams varies. Facilities for water draining and reprocessing of offspec. streams are provided. Flexibility is also provided for alternative routing of streams incase there is change in demand in product pattern. Light and heavy
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 80 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes slop tanks are also provided to receive offspec. Streams __________________ during start up, shutdown, emergencies and upsets in the __________________ plants. The same are reprocessed in the units in a regulated __________________ manner during normal run. By on-line blending and utilising __________________ advanced process control, the tankage for receiving rundown streams can be minimised. Pump stations are provided for __________________ transfer of products. __________________ __________________ 4. Blending the rundown streams __________________ Various straight run streams and secondary processing units __________________ streams are mixed in suitable proportion for the production __________________ of finished marketable petroleum products. The mixture is circulated in the tank to make it of uniform quality. After settling in tank for draining any water and testing the sample in the laboratory to ensure that it meets quality specifications, it is dispatched to market. Storage facility at various locations particularly for MS, SKO and HSD is being augmented. It is proposed to provide 35 days storage capacity based on 75% utilisation factor. 5. Co-ordination with laboratory After blending of various streams and circulation in tank, samples of products are sent to the laboratory for testing. Once the product meets the quality specification as per BIS or customers requirement, then the certificate of quality is issued by the laboratory. Thereafter, product is despatched to market. 6. Despatch of finished products: The certified products are stored in finished product tanks before dispatch. Petroleum products are evacuated from the refinery by following modes: 1. Pipelines 2. Rail 3. Road 4. Coastal
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 4 Integrated Refinery and Petrochemical Plants 81 1. Pipelines: Out of the above dispatch modes of Notes petroleum products, maximum dispatch takes place __________________ through pipelines (60 - 70%). Pipeline systems have __________________ following in-built advantages over other means of __________________ transportation available for petroleum products: __________________ 1. It is the second cheapest mode of transport next to __________________ large capacity tankers. __________________ __________________ 2. With advanced control system and proper __________________ operation, it is possible that the products reach their destination in a "refinery-good" condition. __________________ This is so even in respect of sensitive quality control __________________ products such as ATF, Naptha etc. 3. Minimum transit loss 4. Planned product movement 5. Flexibility in operation independent of other transportation systems. During floods and natural calamities, it is not affected. 2. Rail: Tank wagons are the second bulk carrier specially constructed for this purpose and can take products to far off places. The wagons for transporting heavy products such as FO, LSHS etc, are provided with steam coils for heating the product before unloading at the destination. 3. Road: The third mode of transportation is tank lorries or tank trucks, which are used to supply product to nearby locations by road. Steam coils are provided to heat the product before unloading in case of tank trucks for Bitumen, LSHS, FO, etc. 4. Coastal: Tankers of various capacities are used for dispatch of product from coastal refineries. For short distance and small quantity of coastal product movement, barges are used. The large capacity tankers are the cheapest mode of transport. The products movement of the refinery gets adversely affected due to failure/breakdown of transport system.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 82 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes Flexibility to a small extent exists to switch over from __________________ one mode to other mode. However, refinery builds up __________________ stock in its tanks during such emergencies, to an extent __________________ beyond which through-put of process units is cut thus __________________ affecting the production. __________________ 7. Flare management __________________ __________________ To take care of emergency release of gaseous hydrocarbon, __________________ flare headers are provided for collecting off gases from process units and offsite areas. After seperating the __________________ entrained liquid, the gas is burnt at high point to avoid __________________ hazard and pollution. Three categories of flare systems are provided: a. High pressure flare b. Low pressure flare c. H2S flare 8. Refinery water supply The following important water supply systems exist in the refinery. 1. Fresh water supply system: This provides utility water supply, make up to the circulating water system, make-up to fire water supply system and make up to drinking water treatment system. 2. Fire water supply system: Throughout the process units and offsites areas, the fire water supply pipeline network is laid in the form of ring. Firewater tanks are provided in offsites area to have an immediate supply source for fighting any major fire. In critical areas, long distance throw nozzles are provided. 3. Recirculating hot and cold water system: For cooling of hot products, this system is provided. It is having chemical treatment system to avoid scaling and corrosion in related pipelines and equipment. Cooling Towers are also provided in the system where water is cooled by evaporation before recirculation. Blow-down
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 4 Integrated Refinery and Petrochemical Plants 83 in the form of leakage and manual draining is provided Notes to avoid build up of salt concentration. Make up water __________________ is taken from fresh water system. In some of the coastal __________________ refineries, once through cooling water system is used __________________ and sea water is utilised for the cooling of products. __________________ 4. Captive power plant: To provide uninterrupted power __________________ and steam supply for running the pumps, compressors __________________ and other equipment, captive power plant is provided __________________ in the refinery. For meeting any emergency, alternative __________________ source of power supply from outside is also lined up. __________________ Superheated and saturated steam at various pressures __________________ are also supplied for process units and offsites area from this system. Steam is used for heating, stripping in columns, atomisation of fuel oil before burning in furnace, fire-fighting, driving steam turbines and power generation. Fresh water is used in DM plant before utilising in boilers for steam generation. To ensure supply of steam and power to critical plants/equipment in emergencies, load shedding scheme exists. 5. Fuel oil and fuel gas system: For providing fuel supply to process units furnaces, and boilers in captive power plant, this system is provided. In fuel gas, mostly methane, ethane and purged gases from hydrogen units are used. The supply system is maintained at constant pressure. For fuel oil, varying range of fuels from LDO to Asphalts are used. Storage tanks, blending facilities and pumping system are provided for supply of fuel oil to furnaces and boilers. 6. Hydrogen, Nitrogen and air supply systems: Hydrogen is generated in Hydrogen plant or catalytic reformer unit. It is utilised in hydro-treatment units. It is a very hazardous gas to handle as the flame can not be seen. Nitrogen is used for catalyst regeneration, blanketing tanks from atmospheric oxygen in the case of lubes and other products which form explosive mixture when coming in contact with air, and maintaining inert atmosphere in the process unit equipment. Nitrogen is
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 84 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes produced in generators installed in the refinery or is __________________ purchased from outside. Air is used for utility purposes, __________________ catalyst regeneration, decoking of furnace tubes and __________________ instrumentation etc. It is taken from atmosphere and __________________ compressed before using. __________________ Review Questions for Offsites __________________ __________________ 1. What are the important offsite facilities in a refinery? __________________ 2. How do these facilities affect the proper functioning of __________________ the refinery? Explain each facility wise, specially their __________________ impact whenever there is a failure. Review Questions for all Process Plants 1. Explain briefly in your own works. i. The function of each process plant (11 plants) ii. Feed composition iii. Yield pattern. iv. Critical parameters for optimal operation 2. Which components of various process streams in different process plants (% wise) are utilized for the prouction of LPG, MS, HSD, ATF, Furnace Oil, PC Naphtha and Fertilizer Naphtha.
  • 85 Unit 5 Activity 5 A Describe the scenario of availability of sweet & sour crudes Future Refining Scenario in the next two decades. __________________ __________________ __________________ __________________ __________________ Objectives __________________ After studying the unit, the learner will be able to: __________________ __________________ y Understand Future Refining Scenario in terms of availability of crudes, stringent specifications of various petroleum products, __________________ dwindling refinery margins etc. __________________ y Strategies for overcoming various challenges. Keeping in view environmental considerations, cost optimisation, energy conservation and product quality requirement, it is envisaged that future refineries will have to face many challenges – they will be highly complex, integrated, diversified and fully automated. Worldwide availability of sweet and light crude is decreasing, therefore, future refineries will have to be ready to process heavy and sour crudes. This will call for superior metallurgy in the plants and pre and post treatment of oil products leading to higher capital and operating costs. To improve profitability and meet statutory requirements, following actions need to be taken: u Distillates yield improvement u Production of high value products u Energy optimisation u Hydrocarbon loss minimisation u Effective environmental management u Product quality upgradation u Product inventory reduction
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 86 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Activity 5 B Besides conventional process units, future refineries will also What do you understand from have: Integration of Refinery with petro- chemicals/ fertilizers, power u Quality related units: plants? How does it improve the Bottom Lines? – Facilities for benzene management __________________ – DHDS (Diesel Hydro-desulphurisation) __________________ __________________ – Fuel oil HDS (Hydro-desulphurisation) __________________ – Hydrotreatment. __________________ u Environment management related units: __________________ __________________ – Tail gas treatment __________________ – High efficiency SRUs (Sulphur Recovery Units) __________________ __________________ – Bottom of the barrel upgradation related unit – Computerised integrated refinery – Energy efficient processes – Diversified and integrated refinery with power plant, petrochemicals and fertilizers u Synergy in power with fertilizer co-production – Efficient utilisation of low value refinery residue for production of power. Power plant supplies power and steam required in refinery. – Co-production of value added fertilizer. – No additional raw material handling and common fire fighting facilities. – Overall economics considerably enhanced – Already under way in the USA, the Netherlands and Italy. u Refinery of 21st century – Operate with fewer & highly educated people – Few operators grouped in a central blast proof control room like the cockpit of modern aeroplanes.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 5 Future Refining Scenario 87 – Possible employment of robots Notes __________________ – Computerised system supervising operations __________________ automatically __________________ – On-line analysers and blending __________________ – Computerised performance monitoring __________________ __________________ – Automated dispatch and offsites operations __________________ – Flexible work hours __________________ __________________ In the new refineries, following technology gaps and to be __________________ covered: u Reduction of ‘S’ (sulphur) from MS, HSD and FO. u Reduction of FO production and increase in distillate production to 85%+. u Plant/ equipment should require less space. Review Questions 1. What modifications would be needed in refinery process plants for - Changing over from sweet crude to sour crude - Technological improvements/additions for meeting future more stringent specifications of HSD and MS. So as to conform to Emission norms. - To increase/improve profitability. 2. What do you understand from flexibility of Refinery operations in the competitive environment?
  • 89 Unit 6 Note __________________ __________________ Advances in Petroleum __________________ Refining __________________ __________________ __________________ __________________ __________________ Objectives __________________ After studying the unit, the learner will be able to: __________________ y Understand in a generic fashion advances in refining process technologies - For making eco-friendly products - For value addition to improve the bottomline - For best practices in refining operations - For energy optimization Various issues faced by the refining industry have led to many major developments in this area. The challenges are: 1. Crude oil is becoming heavier and higher in sulphur and metal content. 2. Reduced growth in fuel oil demand. 3. Rapid growth in light/middle distillates. 4. Stringent environmental regulation for cleaner products/processes and demand for quality products. 5. Declining refining margins 6. Improved engine design/automobiles need better quality fuel and lubricating oils. Advances in refining technology can be broadly divided into the following categories. 1. Improved and integrated refining u Production of better quality products
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 90 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Activity 6 A u Residuation in residues/heavier ends What are known/proven improvements as on date, in u Management of power and utilities. Refining Process Technologies? __________________ 2. Value addition __________________ u Petrochemicals production __________________ u Better quality and increased lube oil production __________________ __________________ u Power generation from heavier petroleum products __________________ u Speciality chemicals production. __________________ Improvements are taking place in many areas. Some of them __________________ are listed below: __________________ __________________ u Distillation u Fluid Catalytic Cracking (FCC), Resid Fluid Catalytic cracking (RFCC). u Delayed coking – Needle coke manufacturing, Visbreaker–Soaker Technology. u Hydro processing – Hydro treatment of various streams including residues. – Hydro cracking u Super Oil Cracking (SOC) of heavy distillates to get 90% conversion to distillates. u Mobil distillate Dewaxing (MDDW) to upgrade heavy fuel oil to high quality distillate and gas yield of 93- 95%. u Isomerisation u Catalytic Reforming u Alkylation u Etherification u Power generation by petroleum residue and coke by using Gasification Combined Cycle (GCC) technology.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 6 Advances in Petroleum Refining 91 In this process alongwith power, steam and H2 can be Notes produced which are required in the refinery. __________________ __________________ u More and more use of information technology. __________________ u Modelling simulation are being used for: __________________ – Information Gathering, Decision Making and __________________ Business Profitability. __________________ __________________ – Accurate process models for different processes __________________ (e.g., FCC, Hydrocracking, Cat Reforming, etc) are __________________ being developed and increasingly used for optimization, trouble shooting, design and optimal __________________ control and technology development. – Typical application of information technology in a refinery Guide logistic Refinery Primary planning planning logistic management Refinery Primary Secondary scheduling logistic logistic management management u Significance of process modelling Trouble shooting Reactor Pilot plant design scale up Catalyst Modelling health and Catalyst monitoring simulation selection & optimisation Operator training Process optimisation Feedstock selection u Refinery integration and value addition strategies u Small and medium refineries
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 92 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Activity 6 B – Integration with speciality chemicals for value What are various routes for value addition addition in Petroleum Refining? __________________ – Anode grade coke, needle coke production __________________ – Microcrystalline wax production __________________ – Alpha-olefins production __________________ __________________ u Larger refineries __________________ – Petrochemical integration and speciality products __________________ – Integration of refining and power generation – __________________ IGCC Technology __________________ __________________ – Lubes and fuel integration u Other major strategies of integration – Integration with IT – Process simulation and optimisation – Advanced control and hierarchical control systems Review Questions 1. Explain the following processes and relate the same to the relevant products: - Isomerization - Alkylation - Etherification - DHDS - Catalytic reforming - Catalytic cracking - Thermal cracking (Refer Bibliography) 2. Explain the known/proven processes of Hydrogen Generation from heavy residues/petroleum coke/ coal bed methane? 3. How is IT utilised for improved/on-line performance monitoring of refineries?
  • 93 Unit 7 i. Activity 7 A What should be ideal losses in any Process Control? Hydrocarbon Loss __________________ Minimisation __________________ __________________ __________________ __________________ __________________ Objectives __________________ After studying the unit, the learner will be able to: __________________ y Understand the significance of losses in a refinery and their impact __________________ on profitability __________________ y Understand sources/areas of losses and measures adopted by the refineries for their reduction. During the processing of crude petroleum products, handling and dispatches from refinery, hydrocarbon losses take place on various accounts. Efforts are to be made to bring the loss to a level of less than 0.3% of crude processed. Auditing of the systems and operations will lead to continuous improvement. Following areas need to be monitored/looked into: A. Apparent losses i. Measuring devices in storage tanks and custody transfers for proper accounting ii. Automating road/rail dispatch facilities. B. Real losses i. Vapour recovery from flare and product loading facilities ii. Handling of light hydrocarbon slop in process unit and offsite area in closed blow down system iii. Conversion of fixed roof tanks to floating roof tanks for low flash products including diesel and use of proper type of roof seals.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 94 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Activity 7 B iv. Automatic tank gauging i. What are international standards for Refinery v. Use of proper mixers in crude tanks for minimising Losses? What methods have sludge formation and modern method of removal been adopted in Indian refineries to bring down the and recovery of only sludge/oil to reduce loss losses to International standard? vi. Minimising slop generation to reduce evaporation ii. What is BS&W? How is it loss in slop handling system related with losses in Refining operations? vii. Close monitoring of BSW in crude processed to __________________ avoid plant upsets and increased losses. __________________ viii. Routing of all sour gases to sulphur recovery unit __________________ ix. Routing of off gases from vacuum column to __________________ furnaces. __________________ __________________ Review Questions __________________ 1. What will be the order of magnitude of savings in a six __________________ million tones per year capacity refinery, if the losses __________________ are reduced by 0.2%, cost of crude being $ 25/barrel? __________________
  • 95 Unit 8 i. Activity 8 A What strategies have been adopted to optimize energy Energy Conservation consumption. - For old refineries - For grass-root refineries __________________ __________________ __________________ Objectives __________________ __________________ After studying the unit, the learner will be able to: __________________ y Appreciate the role of/ urgency for energy conservation and optimisation of energy consumption in refining industry. __________________ __________________ y Get a generic idea of various strategies adopted for energy optimisation. __________________ __________________ Conservation of oil and gas has assumed greater importance in view of the emphasis on demand side management of energy. Average fuel loss in the refineries in India during 2000–01 was 7-35% which is higher compared to global levels (of similar configuration). Energy optimisation for a refinery begins early in the development and design stage with the establishment of a set of energy saving guidelines applicable to the project. Some of the areas given below need to be looked into: 1. Integration of heat – exchange system of the units to utilize the heat from hot stream of another unit – crude distillation unit and vacuum distillation units are heat integrated. 2. Optimisation of heat exchangers train – use of pinch technology. 3. Direct hot feed from one unit to another unit without passing through intermediate tanks. 4. Energy efficient processes/equipment such as furnaces, pumps, exchangers etc. Provision of air preheter in furnace. 5. Proper insulation of hot products and steam lines.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 96 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Activity 8 B 6. Optimisation of How do DDCS and advanced process controls help conserve i. Reflux ratio in distillation process energy? ii. Solvent feed ratio in extraction process __________________ __________________ 7. Use of soaker technology for visbreaking. __________________ 8. Use of microprocessor based control system alongwith __________________ DDCS (Digital Distributed Control System) and __________________ advanced process control. __________________ 9. Heat recovery from process streams for heating colder __________________ process streams/ boiler feed water. __________________ __________________ 10. Power generation in new refinery will be through __________________ combined cycle operation integrated with gasification. 11. Steam system – High pressure steam will be cascaded down to lower level by back pressure turbines either generating power or coupled with various key process compressors and pumps. Pressure reduction of steam through a control valve will be minimised. 12. Minimise leakage through glands/seals of pumps, compressors and turbines. 13. Low level heat recovery. 14. Soot blowers for convection section of furnaces to improve heat recovery in furnaces. 15. Steam generation from hot streams. 16. Benchmarking, gap analysis and setting targets. 17. Energy audit for continuous improvement of energy performance. Review Questions 1. How does energy consumption at Indian refineries compare with best run refineries over-seas? Express this in energy consumption indices like - EII (Energy Intensity Index) - NRG Factor in MBTU's per NRGF for fuel + loss
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 8 Energy Conservation 97 2. Explain the role of house-keeping measures for bringing Notes down energy consumption resulting in energy __________________ conservation. Enumerate some important measures of __________________ this nature which the refineries/ chemical industries __________________ take. __________________ __________________ __________________ __________________ __________________ __________________ __________________
  • 99 Unit 9 Notes __________________ __________________ Gross Refining Margin __________________ __________________ __________________ __________________ __________________ __________________ Objectives __________________ After studying the unit, the learner will be able to: __________________ y Provide an appreciation for various elements affecting GRM which in essence is the profitability of a refinery. y Acquaint with the netback estimation method used for selection of crude for any refinery. Gross Refining Margin (GRM) is the differential between the product realisation and the cost of crude processed to obtain these products. GRM of a particular refinery will depend upon various internal and external factors. Some of these factors are discussed below: Internal Factors u The crude mix (low sulphur and high sulphur) processed by the refinery u The secondary processing facilities available with the refinery which affect the product yield of the refinery u The fuel used and losses incurred in the production processes. External Factors u The international prices of various crudes and products u The demand and supply balance of various products refined by the refinery u The duty structure prevailing in the country relating to crude and products.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 100 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Activity 9 A Operating Cost of the Refinery What are various factors which affect GRM? The operating cost of the refinery includes various elements, __________________ some of which are as under: __________________ u Power and fuel: Fuel is used either directly in the __________________ refining process or to generate power and utilities to be __________________ used in the refining process. Fuel may be purchased from __________________ outside suppliers (like natural gas), power from __________________ electricity board or internal refined products (like __________________ LSHS, FO or HSD) may be used as fuel. __________________ u Chemicals and catalysts: During the refining process __________________ of petroleum products, various chemicals and catalysts __________________ are used. The purpose of chemicals is mainly to improve the quality of products so as to meet the desired specifications. Catalysts are used in various reformers and other secondary processing facilities. u Establishment cost: This is related to the manpower deployed and includes the salary and wages paid to staff, overtime, bonus etc. u Repair and maintenance cost: It is incurred in various mechanical, electrical and civil jobs carried out for the maintenance of plant and machinery. u General administrative cost: This cost includes expenses such as traveling. Printing, insurance and other related overhead expenditure. u Depreciation: Operating cost includes depreciation on plant and machinery, furniture, equipment and other fixed assets used in the refining process towards general wear and tear. Net Margin The net margin is the difference between gross margin and operating cost. This is virtually the net profit to the refinery. Net Margin = Gross margin – Operating cost.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 9 Gross Refining Margin 101 For higher profitability, gross margin should be increased Activity 9 B and operating cost reduced by increased efficiency in refining Explain how netback estimation method is used for crude selection operations. Attachment 1 shows a sample calculation for for a refinery? gross and net margin for a refinery. __________________ ATTACHMENT 1: GROSS MARGIN __________________ Rs/Crores __________________ __________________ Realisation of transfer of products 4050 __________________ Cost of crude (inclusive of freight, wharfage, customs duty) 3720 __________________ __________________ Gross margin 330 __________________ Th’put-MMT 3.98 __________________ __________________ GROSS margin Rs/MT 829 Margin – Rs/BBL 112 Margin – US $/BBL US $ 2.30 Less: Operating cost Rs/MT 500 Net margin Rs/MT 329 Net back estimation In the net back system, the estimated realisation is calculated on the basis of expected yield from the particular refinery for a specific crude. For the purpose of procurement of crude for a particular refinery, net back estimation is used to evaluate the suitable crude for the refinery. The crude which is having higher net back to the refinery is normally procured for it. Attachment 2 gives a sample netback calculation to select the best crude out any of seven crudes, considered. All these 7 crudes are sweet (low sulphur) crudes. F.Dos gives the highest netback of Rs 1054/MT vs TAPIS with lowest netback of Rs 41/MT.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 102 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes ATTACHMENT 2: SAMPLE WORKING OF NETBACK CALCULATIONS __________________ PROD BRENT F.DOS BON. LT. LABUAN ESCRAVOS TAPIS MIRI PRICE BL __________________ CRUDE RS/MT 11987 11361 11714 11994 11987 12859 11994 PRICE __________________ LPG 14599 7 5 5 4 2 5 4 __________________ NAP 12260 8 0 5 2 5 10 3 MS 14832 12 12 12 12 13 12 12 __________________ SKO 13617 11 11 11 11 11 11 11 __________________ HSD 14361 48 58 54 58 51 53 59 OF 10100 0 0 0 0 0 __________________ L.SHS 10100 1 0 0 0 6 0 0 __________________ RPC 5535 2 1 1 2 6 1 1 SULPHUR 256 1 1 1 1 0 1 __________________ SL. WAX 13851 0 0 0 0 0 0 0 __________________ F&L 0 10 12 11 10 6 8 9 TOTAL 100 100 100 100 100 100 100 DIST% 86.0 86.0 87.0 87.0 82.0 91.0 89.0 CRUDE 11987 11361 11714 11994 11987 12859 11994 VALUE,RS/MT PROD 12408 12415 12454 12570 12593 12900 12780 VALUE, RS/MT LESS IPN 100 100 COST, RS/MT NET BACK, 421 1054 740 476 606 41 686 RS/MT Review Questions 1. What are the most crucial factors and which are indeed controllable, affecting GRM? 2. What are various options for reducing Refining Costs in competitive world?
  • 103 Unit 10 Notes __________________ __________________ Oil Accounting __________________ __________________ __________________ __________________ __________________ __________________ Objectives __________________ After studying the unit, the learner will be able to: __________________ y Provide a general idea of accounting methods for crude and petroleum products and its significance. While the physical handling of crude oil, intermediates and finished petroleum products is done by operations personnel, the Oil Accounting Section of the finance department of a refinery/warehouse is responsible for correct depiction of the quantitative and financial records pertaining to the crude oil and petroleum products. Quantitative accountal and correct payment of duties on finished petroleum products is the focal area of the oil accounting section. The following are its key functions. 1. Accounting of Crude Oil Receipts and Duty Implications Thereon Crude oil received under bond from port locations and re- warehoused in a refinery needs to be accounted on FIFO basis and appropriate customs duty is required to be paid and accounted for the quantity taken in the process of refining. This is known as ex-bonding of crude. 2. Accounting of Manufactured Petroleum products and Those Received for Blending, etc. The duty liability on petroleum products arises when the process of manufacture is completed, although the discharge of duty obligation is allowed to be deferred to the time of removal from the refinery/onward removal to warehouse. Hence, tank accountal of receipts and removals is to be
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 104 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Notes maintained by taking dip measurements and quality testing __________________ reports. __________________ 3. Despatch of Finished Petroleum Products __________________ __________________ Assessment to central excise duties is invoice-based. Whether __________________ the goods removed are duty-paid or under bond, the excise duty liability is determined at the time of removal from the __________________ refinery warehouse. With the invoice being the document in __________________ support of cenvat credit claim that may accrue to a customer, __________________ the invoice/application for duty-free removal is the __________________ cornerstone for correct excise assessment of removals. __________________ 4. Compliance of Excise Procedure and Maintenance of Records The excise department tests compliance of law and procedure primarily through the records maintained by the oil accounts section of the assessee. For duty-paid goods, the liability likely to arise during a working day is to be deposited in advance through treasury challan at the bank and the deposit credit is to be utilised in accordance with the invoices issued for the clearances. This is done through the PLA (Personal Ledger Account). The DSA (Daily Stock Account) is to be maintained for opening balances, production, dispatch and closing balances of all certified finished products of the refinery warehouse. Intimations/declarations are to be submitted to the range office for any act or action that may be regarded as having an impact on revenue. 5. Material Balancing, Production Statistics and Periodical returns and Statements As the crude oil is processed through a combination of distillation and blending, intermediary products arise during the course of manufacture of certified finished petroleum products. The control over inputs and outputs during this refining process is achieved through the daily material balancing done through the quantitative measurement of tank and line-fill quantities of the crude, intermediaries and finished products. The production statistics are correlated to the standard product pattern and the actual distillate yield for any particular period of time.
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 10 Oil Accounting 105 Statutory returns as per excise procedure are filed Notes periodically by the oil accounts section with the range office. __________________ Records, returns, documents, etc prepared by the oil __________________ accounting section are open to inspection by the range office. __________________ Letters, show cause notices, if any, are normally issued __________________ through the oil accounts section. __________________ Review Questions __________________ __________________ 1. Method and system of accounting crude and petroleum __________________ products in a refinery? __________________ 2. How is the excise/customs procedure followed by oil __________________ accounting section?
  • 107 Unit 11 Activity 11 A What is the present level of custom and excise duties on crude and Excise and Custom – Petroleum various petroleum products? What is the rationale for fixing the same? Products __________________ __________________ __________________ __________________ __________________ Objectives __________________ After studying the unit, the learner will be able to: __________________ y Give an overview of excise and customs procedures/formalities __________________ as applicable. __________________ y Provide an appreciation for the manner in which custom and excise duties affect profitability. __________________ The removal of petroleum products manufactured in refineries is either to direct customers or through marketing network (warehouses/ depots/terminals, etc) for sale therefrom. Products belonging to oil marketing companies are also dealt through intercompany transactions. These products are either removed on payment of excise duty, or under bond without payment of excise duty. In the latter case, the duty obligation on the manufactured goods is discharged from the warehouse when it is finally cleared for sale. In certain cases, the goods are removed under bond to special industrial undertakings like SEBs, FCI, etc who are licensed to deal with manufactured excisable goods without payment of duty. The products are removed through pipelines, tank wagon (railways), tank lorries (oil tankers), or barges (through waterways). The primary raw material for finished petroleum products is crude oil, indigenous and imported. Indigenous crude oil attracts Nil rate of excise duty, whereas imported crude oil attracts 10% customs duty. Indigenous crude oil is sourced from Gujarat and Assam oilfields and from offshore oilfields of India. Imported crude of different varieties as per
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES 108 Refining fo n ~; k ; k ‘ k f D r o’ k~ e Activity 11 B processing requirement are brought through different ports When is it desirable to export/ of the country. import any product based on custom/excise duties prevailing? While crude oil only attracts the basic customs duty, other __________________ items of import attract additional duty of customs (equivalent __________________ to the excise duty attracted for such items under the central __________________ excise tariff) and special additional duty of customs on selective basis as notified. The additional duty of customs __________________ levied under the Customs Tariff Act and the excise duty __________________ levied under the Central Excise Tariff Act are allowed to be __________________ set-off as duty credit by the refineries (manufacturer) under __________________ the Cenvat Credit Scheme of central excise. During discharge __________________ of excise duty obligations arising on the removal of finished __________________ petroleum products from the refineries on duty-paid basis, the refineries use the accumulated cenvat credit in lieu of __________________ cash payment. Other than basic excise duty, there is a levy, on selective basis by notification, of special excise duty, additional duty of excise (Re. 1 per litre on Motor Spirit commonly known as petrol and on high speed diesel oil commonly known as diesel), and recently introduced special additional duty of excise on MS. Petroleum products are handled under the Self- Assessment Scheme of Self Removal Procedure (SRP) of central excise. The excise assessee is required to take necessary actions to be within the legal and procedural requirement of excise and customs law, without physical supervision of the department. At the refinery/warehouse, the department is represented by the jurisdictional officer- in-charge (superintendent) of the Excise Range Office who has been given power of unified customs and central excise control over imported crude oil and excisable finished products of the refinery. Review Questions 1. In the event of excess refining capacity (with glut in the market), what level(s) of production should be maintained to meet domestic demand and export the product? 2. What is the significance of bonded warehouse? How are crude and products removed and accountal done?
  • OLEUM & E TR EN FP ER YO GY u UNIV ER SIT ST U DI ES fo n ~; k ; k ‘ kf D r o’ k~ e UNIT 11 Excise and Custom – Petroleum Products 109 Bibliography Notes __________________ 1. Advanced Petroleum Refining, Dr. G.N. Sarkar, Khanna __________________ Publishers, Delhi __________________ 2. Reading Material of Programme on Petroleum Refining __________________ and Petrochemical Technology, Indian Institute of __________________ Petroleum, Dehradun. __________________ 3. Reading materials of programme on Refining & __________________ Petrochemicals of various Petroleum Companies. __________________ __________________ 4. Petroleum Refining Engineering, W.L. Nelson, Mc.Graw __________________ Hill. 5. Handbook of Petroleum Refining Process, Robert A. Meyers 6. A layman's Introduction to Oil Refining - D.G. Crook 7. "Managing Modern Offsite Operation" by Patrick B. Truesdale and J. Dauglas AMOS 8. Course contents on Refinery Loss Control by Dr. Eric Robinson and Dr. John Miles at Singapore, 20-21st May, 1996. References 1. Advanced Petroleum Refining, Dr. G.N. Sarkar, Khanna Publishers, Delhi 2. Petroleum Refining Engineering, W.L. Nelson, McGraw Hill 3. Modern Petroleum Refining Processes, Dr. B.K. Bhaskar Rao, IIT, Kharagpur 4. Advances in Petroleum Chemistry and Refining - Kennetha A. Kobe, John J. Moketta 5. The Chemistry and Technology of Petroleum (Mercel Dekkar), Speight J.G. 6. Petroleum Monthly Publication, Malaysia 7. Hydrocarbon Processing 8. New Challenges, Technologies Options for Refineries - IOC, R&D Report No. 96018, March, 1996 9. KBC Petrofine Users Manual 10. A Layman's Introduction to Oil Refining - D.G. Crook 11. Refinery Loss Controls - Course Manual Presented by Dr. Eric Robinson and Dr. John Miles on 20-21 May 1996 at Singapore.