Project report on Indian Oil Corporation Limited (IOCL) on account of winter Industrial training. Internship report - Dated 17/01/2019

1. WINTER TRAINING REPORT ON INDIAN OIL CORPORATION
LIMITED GUWAHATI REFINERY
TRAINING PERIOD: 02.01.2019-17.01.2019
SUBMITTED BY:
PRIYAM JYOTI BORAH (CHE 16/275)
Students of B.E (Chemical Engineering)
Assam Engineering College

2. NAME OF THE CO-ORDINATOR
(OFFICER (L&D))
--------------------------------------------------------------------------
Sh. Keshav Kumar
NAME OF THE CO-ORDINATOR
(PRODUCTION ENG.)
--------------------------------------------------
Sh. Bardan Lama
2

3. Acknowledgment
We would like to take this opportunity to express gratitude to the training
department of Indian Oil Corporation Limited, Guwahati Refinery for
granting us the opportunity to be a part of this esteemed organization as a
vocational trainee. We want to thank Sh. Keshav Kumar Sir (CPNM) for his
constant assistance provided during the time of this training. We would also
like to thank the fire and safety department, Guwahati refinery, Indian Oil
Corporation Limited for making us aware of the various risks and potential
hazards present in the refinery campus and the measures taken to mitigate
them.
We are grateful to Sh. Bardan Lama Sir (PNM) for his constant guidance during
the course of this training. We would like to thank Dr. Atul Borah sir, Principal
of Assam Engineering College for encouraging us to undergo this vocational
training in IOCL. We will be doing injustice if we forget to thank all the shift
in-charges and engineering assistants who dedicatedly educated us about the
processes undergoing in the plant. Last but not least, we would like to thank our
parents for their constant help, support, and guidance.
3

4. PREFACE
Any amount of theoretical knowledge is incomplete without exposure to
industrial practice. Industrial training plays an essential role in the progress of
future engineers. Not only does it provide insights about the future concerned,
but it also bridges the gap between theory and practical knowledge. Hence, in-
plant training is of great importance for engineering students.
We got the opportunity to undergo our industrial training in Guwahati Refinery
of Indian Oil Corporation for 15 days. The experience gained during this period
was highly educative for us. As a trainee, we learned about the different units
incorporated in refining processes and maintenance work being carried out in
the refinery. We also got to learn about how to mitigate an industrial accident.
During our training, we realized that to be a successful chemical engineer one
needs to put his/her concepts into action. The training serves as a stepping
stone for us in becoming a sound engineer and helps us carve a niche for
ourselves in this field.
4

5. CONTENTS
S. TOPICS PAGE NO.
NO.
1 ABSTRACT 7
2 INTRODUCTION 8
3 FIRE AND SAFETY DEPARTMENT 10
4 PRODUCTION DEPARTMENT 12
5 CDU 13
6 HGU 16
7 HDT 19
8 INDAdeptG
23
9 SRU 26
10 OM & S 28
11 ETP 29
12 DCU 33
13 INDMAX 36
14 MSQU 38
5

6. 15 PROJECT 49
16 CONCLUSION 55
17 BIBLIOGRAPHY 56
6

7. ABSTRACT
This report is prepared at Indian Oil Corporation Ltd,
Noonmati, Guwahati as a part of Industrial Training and
contains a brief description of the refining process employed
in the refinery. It mainly focuses on the process description
of various Units and respective process flow diagram of those
units. The details of each unit are briefed as a part of practical
training along with the methodology and the procedure
adopted are also included in this report.
7

8. INTRODUCTION
An oil refinery or petroleum refinery is an industrial process plant where crude oil is
transformed and refined into more useful products such as petroleum naphtha, gasoline,
diesel fuel, asphalt base, heating oil, kerosene, liquefied petroleum gas, jet fuel, and fuel
Oils. Petrochemicals feed stock like ethylene and propylene can also be produced directly by
cracking crude oil without the need of using refined products of crude oil such as naphtha.
Oil refineries are typically large, sprawling industrial complexes with
Extensive piping running throughout, carrying streams of fluids between large chemical
processing units, such as distillation columns. In many ways, oil refineries use much of
the technology of and can be thought of, as types of chemical plants.
The crude oil feedstock has typically been processed by an oil production plant. There is
usually an oil depot at or near an oil refinery for the storage of incoming crude oil
feedstock as well as bulk liquid products.
Petroleum refineries are very large industrial complexes that involve many different
processing units and auxiliary facilities such as utility units and storage tanks. Each refinery
has its own unique arrangement and combination of refining processes largely determined
by the refinery location, desired products, and economic considerations.
An oil refinery is considered an essential part of the downstream side of the petroleum
industry.
Indian Oil Corporation Limited, established in 1959 is India’s largest commercial enterprise.
It serves mainly India, Sri Lanka, Mauritius, and the Middle East. The main products are
fuels,
lubricants and petrochemicals. Indian Oil Corporation Limited owns ten of India’s total
twenty-two refineries, which are situated
Barauni,Panipat,Mathura,Koyali,Guwahati,Haldia,Digboi,Bongaigaon, Narimanam . As
India’s flagship national oil company, Indian oil accounts for 56% petroleum products market
share,42% refining capacity, and 67% downstream pipeline throughput capacity.
Guwahati refinery is the country’s first public sector Refinery as well as Indian Oil’s first
refinery serving the nation since 1962. Built with Rumanian assistance, the initial crude
processing capacity at the time of commissioning of this refinery was 0.75 MMPTA, and
the refinery was designed to process indigenous Assam crude. The refining capacity was
subsequently enhanced to 1 MMPTA. Due to the dwindling supply of indigenous Assam
crude
8

9. , Guwahati Refinery started processing low sulfur imported along with Assam crude.The
supply of LS imported crude to Guwahati refinery is from Barauni Refinery via Railway
wagons.
The Refinery supplies various petroleum products to North-eastern India as well as beyond,
up to Siliguri end through the Guwahati-Siliguri pipeline, spanning 435KM, which was the
first pipeline of Indian oil and commissioned in 1964. Most of the products of Guwahati
Refinery are evacuated through the pipeline and some quantity also through road
transportation.
LPG, Naphtha, Motor Spirit (MS), Aviation Turbine fuel, Superior Kerosene oil, High-Speed
Diesel (HSD), Raw Petroleum Cake and sulfur are the products of this refinery.Auto Fuels
MS and HSD supplied by the refinery are of eco-friendly BS-IV grade as per statutory
guidelines of the government of India.The production of these valuable petroleum products is
through a series of different primary and secondary processing units along with the associated
auxiliary facilities like captive power plant installed within the refinery.
9

10. FIRE AND SAFETY DEPARTMENT
Fire and safety department of Indian Oil Corporation Limited is concerned about the fire
hazards and safety of the company employees and labors. Fire and safety officials train the
labors in a daily manner. A person can enter the battery area if and only If he/she has a
safety pass. This safety pass is issued by the Fire and Safety Department officials only.
IMPORTANT TERMINOLOGIES:
SAFETY: Safety is a condition which gives us freedom from hazards, risks accidents
which may cause injury, damage, and loss of materials or property and even death.
ACCIDENTS: It is an unexpected or unplanned event which may or may not result in injury
or damage or property loss or death.’
INJURY: It is defined as harmful conditions sustained by the body as a result of the
accident.
HAZARDS: Inherent properties of a substance or an occurrence which has the potential to
cause loss or damage to properties or life.
RISK: It has the probability of the potential for loss or damage or injury.
SAFETY MEASURES:
Different safety measures are taken to reduce the chances of hazards. Mobiles, laptops, pen
drives and cameras are prohibited inside the battery area. Cars which are allowed to enter the
battery area are provided with spark arrestors. Cigarette, alcohol and other inflammable
objects are not allowed inside the battery area. Fire alarms and Fire Extinguishers are present
within a considerable distance inside the refinery. Workers are always advised to use their
PPEs.
Personal protective equipments or PPEs
Personal Protective Equipments are provided for the workers. These equipments are
as follows:
• Safety shoes/Gumboots for protection of feet
• Safety helmet for protection of head
• Face shield for protection of face
• Ear plug and ear muffs for protection of ears
• Hand gloves for protection of hands
• Apron for protection of body
• Dust mask for protection of nose
• Safety goggles for protection of eyes
• Safety belts for work at height
10

11. The major types of siren codes are:
• A continuous test siren is sounded every morning at 7am for 2 minutes.
• Small fire-no siren
• Major fire-a wailing siren for 2 minutes
• Disaster-3 times wailing siren for 2 minutes at intervals of 1 minutes in
between (8 minutes in total)
FIRE EXTINGUISHER:
Three types of fire extinguishers are there:
• Dry chemical powder (DCP)-for control of any type of fire
• CO2 gas extinguisher-for control of electrical fire hazards
• Foam for control of liquid/oil fire hazards
Red and Green tag system is therefore marking of an object. Workers are always advised
not to use the red gas objects as they cause an accident.
There are also 5 assembly points in the refinery. All employees and workers are advised
to assemble there in case of a siren.
The aim of Indian Oil Corporation Limited is Zero Accident and Fire and
safety department plays an important role in that.
11

12. PRODUCTION DEPARTMENT
The production unit is the heart of the refinery. In this department, the crude is processed and
its components are extracted. The products are treated to meet the market quality. The
storage and movement of oil also comes under this department. The production department
consists of the following units:
• Crude Distillation Unit (CDU)
• Motor Spirit Quality Project (MSQ)
• Delayed Coker Unit (DCU)
• Hydrogen Generation Unit (HGU)
• Hydrotreater Unit (HDT)
• INDAdeptG
• INDMAX
• Sulphur recovery unit (SRU)
• Effluent treatment plant (ETP)
• Oil Movement & Storage (OM&S)
12

13. CRUDE DISTILLATION UNIT
The crude distillation units (CDU) is also called primary or mother unit of refinery. The
function of this unit is to receive crude oil and treat them by fractional distillation and
recover their components.
COMPOSITION OF CRUDE OIL
Crude oil is basically an oily liquid which is reddish brown or black in colour. It is composed
of hydrocarbons and its derivatives containing sulphur, nitrogen, oxygen and metals (nickel,
vanadium).
Crude oil contains around 82%-87% carbon, 11%-15% hydrogen and oxygen, nitrogen,
sulphur and other metals (Ni, V, etc) constitute the remaining. It is practically impossible
to determine exactly the composition of a particular grade of petroleum. So, petroleum is
analysed usually to ascertain their gap composition.
Main constituents of petroleum hydrocarbons:
1. Paraffinic hydrocarbons (alkanes)
2. Naphthenic hydrocarbons (cycloalkanes)
3. Benzene hydrocarbons (arenes)
4. Unsaturated hydrocarbons (olefins)
5. Oxygen containing compounds
• Naphthenic acids
• Phenols
• Tar-asphaltene
6. Sulphur compounds
7. Nitrogen compounds
8. Mineral substances
PROCESS DESCRIPTION
Crude from the battery limit, is pumped at 15.8 Kg/cm2
by pump P-1. It passes through a
preheated train where it is heated to 130 o
C and enters the desalter(V-101). In desalter,
demulsifier mixed crude is mixed with hot water through a mixing valve. Thus, the salt in
crude, dissolves in water and separated from the crude. The remaining salted water
droplets are removed in the presence of electric field. The effluent water is used to preheat
the incoming wash water in E101 before being sent to desalter wash water vessel. The
desalter pressure is maintained at about 13 to 15 Kg/cm2
.
From desalter, the crude enters the Pre-topping column (CL-1) from top for pre-fractionation.
From this column (IBP- 110o
C), TBP cut is drawn out from the top as light gasoline to stabilized
feed surge drum (V-005). The rest of the topped crude is pumped by pump P-2 to atmospheric
furnace (C-1A) via a train of exchangers at about 265o
C. The furnace is vertical
13

14. cylindrical type that has two passes with bottom firing having convection and radiation
section. The topped crude enters on flow control to each of the two passes of the furnace.
Crude is heated to 365 o
C, gets partially vaporised and goes to Flash zone of Main
Fractionating column (CL-2). In the main fractionating column, crude is separated into
different products of different cuts. The overhead of the column is collected in main
fractionating column reflux drum (V-2). The hydrocarbons from V-1 are pumped by pump
P-515 as heavy gasoline to NSF feed surge drum (V-001). From column (CL-2), three cuts
are drawn: SR Kero-I, SR Kero-II and SRGO. These are routed to stripper, CL-3A, CL-3B
and CL-3C respectively. After that each product pumped out from stripper bottom through
exchanger and cooler to respective storage tank at around 40C֯. The bottom portion of CL-2
pumped out by pump P-9/9 as reduced crude oil (RCO) through exchanger and cooler to
storage tank at around 90֯C or it can be directly used as feed as DCU at around 110C֯ . The
unstabilized Naphtha or light Gasoline from stabilizer feed surge drum (V-005) is routed to
stabilizer (C-003) through a train of exchanger at around 125C֯. From top, LPG is recovered
and is pumped out by pump P-008 to the storage vessel. The bottom comes out as stabilized
Naphtha which is routed to Splitter-1.
Heavy gasoline from NSF feed surge drum and stabilized naphtha from stabilizer are sent to
splitter-I (C-001) through a train of exchangers. The top product at around 40-120 o
C, is
pumped out as Light Naphtha (LN). From bottom, a part of the product is heated in furnace
and circulated again in column and the remaining part goes to splitter-II (C-002). In C-002,
the top product at around 100-160 o
C, is drawn as Reformed Naphtha (RN) and is sent to
storage tank. From bottom, a part of the product is heated in furnace F-002 and circulated
again in column and the rest is pumped out as Heavy Naphtha (HN). Heavy naphtha is
mixed with Kero-II and SRGO (straight run gas oil) and goes to gas oil tank.
For the recovery of valuable fuel gases (hydrocarbon mix) from flare header line by
implemented a small unit Flare Gas Recovery System (FGRS). The flare gas coming from
nozzle N1 ex. Main flare header of 36” out drum enters the compressors at a temperature of
about 45C֯. inside the compressors it is compressed up to 4.5 kg /cm²g and a temperature of 46C֯.
During the compression gas/liquid mix runs into gas/liquid separator 07-FR4D-01. The
compressed gas leaves the separator from the top nozzle at 6.5kg/cm² to the fuel gas heads,
hydrocarbon condensate goes to slop and condensed de-mineralized water goes to OWS.
14

15. 15

16. HYDROGEN GENERATION UNIT
Hydrogen production has become a priority in current refinery operations and when
planning to prepare low sulphur gasoline and diesel. It also supplies Hydrogen to Hydro
treating Unit (to meet out the cetane specific in diesel fuels) and MSQU Unit (to meet the
octane and aromatic specification of gasoline fuels).
The unit was licensed by Technip, Benelux and has a capacity of 10000 TPA. It uses the
technology Steam Reforming and PSA (Pressure Swing Adsorption). It was commissioned
on 6 October 2002.
PROCESS FEATURES
• Feed preparations: Removal of Sulphur and Chlorides and saturation of
olefins. Absorption of HCl and H2S by Na-Aluminate and ZnO bed.
• Pre-reforming section: Conversion of Naphtha to CO, CO2, H2, and CH4.
• Reforming section: Conversion of CH4 to CO, CO2 and H2.
• HT and LT Shift conversion section: Conversion of CO and H2O to CO2 and H2.
• PSA units: Purification of H2 from CO, CO2, CH4 in exiting reformer HT-LT
downstream gases.
CHEMICAL REACTIONS
HYDROGENATOR
• RSH + H2
• RCl + H2
• R=R + H2
→
RH + H2S
→
RH + HCl
→
RH-RH
DESULPHURISER AND CHLORINE GUARD
• HCl + Na-Aluminate
→
NaCl + H2O
• H2S + ZnO
→
ZnS + H2O
PRE-REFORMER
• CnHm + n H2O
→
n CO + (n+m/2) H2 (Endothermic)
• CH4 +H2O
→ CO +3 H2 (Endothermic)
• CO + H2O
→ CO2 + H2 (Exothermic)
• Desulphurized feed along with excess H2 is mixed with HP saturated steam and
passed over pre-reformer and reformer in series.
• Activity of the pre-reformer catalyst is indicative by % conversion of HC to H2 and
CO.
• Excess hydrogen is required to maintain reduced condition of Pre-Reformer and
Reformer catalyst.
REFORMER
• CnHm + n H2O
→
n CO + (n+m/2) H2 (Endothermic)
• CH4 +H2O
→ CO +3 H2 (Endothermic)
• CO + H2O
→
CO2 + H2 (Exothermic)
16

17. HIGH TEMPERATURE (HT) SHIFT REACTOR
• CO + H2O
→
CO2 + H2 (Exothermic)
LOW TEMPERATURE (LT) SHIFT REACTOR
• CO + H2O
→
CO2 + H2 (Exothermic)
BASIC DESCRIPTION OF THE PROCESS
MAIN SECTION OF HGU:
• Feed treatment section
• Pre-reformer
• Reformer
• Shift reaction
• Pressure Swing Adsorption (PSA) operation
Naphtha feed from surge drum V-02 is pumped to E-02 A/B feed vaporizer. Recycle
hydrogen is mixed with feed stream before the vaporizer. After vaporizer feed goes to heat
exchanger (E-24) for further heating to 230o
C. then, it is sent to hydrogenator (R-01) for
hydrogenation of organic sulphur and chlorine compounds to H2S and HCl respectively. The
inlet temperature of hydrogenator is 356o
C and outlet temperature is 360o
C. HCl is adsorbed
in alumina-based catalyst and H2S is adsorbed in ZnO based catalyst in R-02. Here, the
sulphur content is reduced to less than 0.1 ppm. The de-sulphurised and dechlorinised feed is
mixed with the high pressure (HP) steam and heated to 450o
C in exchanger E-22. This
stream goes to pre-reformer R-03, where controlled reforming reactions change the feed to
methane. The outlet of R-03 is heated in exchanger E-21 to 650o
C and passed through
reformer (F-01) tubes. The temperature inside the tubes is maintained at 800o
C. In reformer,
the reforming reaction takes place and the feed and steam is converted to CO, CO2, H2. The
steam reformed gas outlet from reformer contains CO, O2, H2, unconverted CH4 and
unutilized steam. The process gas at outlet of reformer is at around 830o
C, which is cooled
to 320o
C in waste heat boiler (WHB) and boiler feed water (BFW) preheaters and passed
through HT shift converter R-04 and LT shift converter R-05.
In shift converters, the carbon monoxide on reaction with steam gets converted to H2 and
CO2. The unutilized steam is condensed in step cooling, downstream of R-05 and then the
reformed gas is sent to PSA to remove the CH4, CO, CO2 and produces 99.999% pure
hydrogen.
17

18. 18

19. HYDROTREATER UNIT
Normal capacity of the hydrotreater is 0.6 MMTPA of fresh feed. However, the unit is
designed for the throughput of 0.66 MMTPA of fresh feed (a cushion of 10% on design
capacity is kept). The unit will be operated in two blocked out modes: kerosene and
diesel. Occasionally, the unit will operate in a blocked-out mode to produce ATF.
The HDT unit reduces the sulphur content of diesel by treating it with hydrogen at high
temperature and pressure over catalyst to convert the bound sulphur in the diesel to H2S.The
unit is also able to achieve 48.5 cetane no. during diesel operation (EOR) and 21mm smoke
point during kerosene operation (EOR).The unit also have the flexibility to process straight
run kerosene-1 alone to produce aviation turbine fuel (ATF) if it is required.
PROCESSING STEPS INVOLVED
• Pumping of feed to desired pressure.
• Mixing recycle gas with feed.
• Heating of feed and recycle gas mix to desired temperature.
• Contacting the feed and recycle gas mixture with catalyst.
• Cooling of the reactor effluent.
• Separating liquid and vapour from reactor effluent.
• Recycling the separated gases to reactors inlet.
• Stripping the liquid reactor effluents to remove lower boiling fractions as
wild naphtha.
• Cooling and polishing of product before sending to storage.
Catalyst selected are oxides of Ni or Co and Mo, impregnated on alumina base. Catalyst
selection depends on type of feed stock, desired product properties and process design
conditions. The economical combination of these factors determine the best overall
catalyst system.
CHEMICAL REACTIONS
SULPHUR REMOVAL
The typical feedstock to the unit will contain simple mercaptan, sulphides and disulphides.
These compounds are easily converted to H2S. However feedstock containing heteroatomic
aromatic molecules is more difficult to process. Desulphurisation of the compounds proceeds
by initial ring opening and sulphur removal followed by the saturation of the resulting olefin.
• Mercaptan: C-C-C-C-SH + H2
→
C-C-C-C + H2S
• Sulphide: C-C-S-C-C + 2H2
→
2C-C + H2S
• Disulphide: C-C-S-S-C-C + 3H2
→
2C-C + 2H2S
• Thiophenic:
19

20. NITROGEN REMOVAL
Denitrogenation is generally more difficult than desulphurization. Side reactions may yield
nitrogen compounds more difficult to hydrogenate than the original reactant. Saturation of
hydrogenated nitrogen containing rings is also hindered by large attached groups. The
reaction mechanism is:-
OXYGEN REMOVAL
Organically combined oxygen is removed by hydrogenation of the carbon-hydroxyl
bond forming the water and the corresponding hydrocarbon. Phenols:-
C6H5OH + H2
→
C6H6 + H2O
OLEFIN SATURATION
Olefin saturation reactions proceed very rapidly and have a high heat of reaction.
AROMATIC SATURATION REMOVAL
This process is the most difficult and is highly exothermic.
C6H6 + H2
→
C6H12
BRIEF DESCRIPTION OF THE PROCESS
The feed, consisting of Kero-I and Kero-II, from gas blanketed storage tanks is passed on to
diesel/kerosene transfer pumps. The pump raises feed pressure to 8.4 Kg/cm2
g. the pumped
feed is directed to feed coalescer where water is coalesced from the feed. This is provided
with a water boot where water coming along with feed gets separated. The feed is sent to
backwash type filter and is designed to retain particles of size more than 2 microns.
Filtered feed is directed to the shell side of feed preheat exchanger where it gets heated by
stripper feed bottom exchanger tube side effluent. The preheated feed passes on to feed surge
20

21. drum where its pressure is maintained by nitrogen and split range controller. Feed then
passes on to charge pumps, which pumps it to around 120.9 Kg/cm2
g and direct it to cold
combined feed exchangers. Feed pumps take suction from feed surge drum and its discharge
passes through effluent-feed cold exchangers and hot combined feed exchangers.
Recycle gas from compressors goes to upstream of cold combined feed exchangers. The
feed-gas mixture after being preheated pass on to charge heater, for further heating to proper
reactor inlet temperature. It reaches to inlet temperature at around 354-385o
C (for diesel).
Combined feed passes on to reaction over catalyst beds. The DHDT unit has been designed to
improve HSD cetane number to 48.5 and reduced sulphur to 0.05 wt%. the feed enters from the
top of the reactor. As the reactants flow downwards through the catalyst bed, various exothermic
chemical reactions take place and the temperature of the flowing stream increases. The outlet
temperature is around 400o
C. The effluent passes through tube side of heat exchangers where it
exchanges heat with the reactor feed. Then, it is passed on to tube side of stripper feed/reactor
effluent exchangers, where they exchange heat with stripper feed.
Reactor effluent outlet from exchangers goes to reactor effluent air cooler and finally to high
pressure separator. Wash water is injected into the stream before it enters the condenser in
order to prevent the deposition of salts that can corrode or foul the coolers. Vapour, liquid
and sour water are separated in separator, which is a horizontal vessel with a water boot on its
underside. Hydrocarbon liquid is separated from the vapour and aqueous phases and leaves
from the bottom of the vessel to the stripper feed/bottoms exchanger. The vapour phase from
the vessel is sent to recycle gas knock out drum and finally to recycle gas compressor suction.
Stripping steam (MP) is given at bottom of stripper to control flash point of diesel. Vapours
leaving the top tray are directed to the air cooled stripper overheads trim condenser followed by
water cooled stripper overheads trim condensers. Vapour-liquid mixture from condensers is
directed to the stripper receiver where separation of vapour, liquid and water takes place.
Vapours from the separator pass on to the stripper off gas knock out drum. hydrocarbon
liquids are directed to the stripper overheads pumps and sent to top tray as reflux. A part of
discharge is drawn and sent to CDU/DCU as unstabilized overhead liquid (naphtha)
product. Bottoms are directed to stripper bottoms pumps and sent through exchangers and
product coolers to diesel product coalscer and finally to tanks after separation.
21

22. 22

23. INDAdeptG
UNIT
It is a Naphtha Adsorption Desulphurization Unit technology developed by IOCL R&D. It
is used to treat 3500 MTPA of heavy cut of INDMAX gasoline. Product gasoline will have
sulphur content less than 50 ppmw and can be blended with motor spirit (MS) without
affecting the required quality to meet BS-IV specs. It is designed on the basis of deep
desulphurization of heavy gasoline which is generated from 3 cut splitter of INDMAX unit.
The purpose of this unit was that IOCL Guwahati Refinery was interested to augment the
capacity of existing INDMAX unit to 150% of design. It would lead to more heavy gasoline
generation. A part of it goes to motor spirit (MS) and the other part is sent to diesel pool.
SALIENT FEATURES
• Reduces sulphur content<10ppm
• Uses low cost patented adsorbent
• Saves 20-30% overall hydrogen consumption as compared to other competing
technologies.
• Lower octane loss (2-3 units)
PROCESS DESCRIPTION
INDAdeptG
comprise of four main sections:
• Demetallation section
• Adsorption section
• Regeneration section
• DESOX section
DEMETALLATION SECTION
In this section, feed which is a mixture of naphtha and hydrogen at 300o
C and 20 Kg/cm2
pressure, is passed through a DEMET reactor. This reactor is basically a metal guard that
consist of 3 layers of catalyst guard, that is, DEMET catalyst, arsenic guard and silica
guard. Metals such as Ni, V, Na, Ca, Mg, P, Fe, Si and As are poisonous to INDAdeptG
adsorbent even at ppb level. Hence, it is necessary to remove them.
ADSORPTION UNIT
Heavy cut gasoline (90%) at 160o
C and 8 Kg/cm2
g pressure and from storage tanks at 40o
C and
0.35 Kg/cm2
g pressure are pumped through naphtha cold feed pump to filter to remove solid
particles. The feed then passed on to coalecser and stored in feed surge drum. it is is pressurized
by naphtha feed pump to 23 Kg/cm2
g and mixed with recycle H2 from recycle gas compressor.
The mixture is the passed through reactor feed/effluent exchangers where it is heated to 263o
C
(vapour state) and further heated to 300o
C in an electric heater. The feed is then passed through
metal guard and enters the reactor operating under adsorption from the
23

24. top. During this period, the other reactor will be operating in regeneration mode. The reactor
consists of 2 adsorbent beds and the temperature is controlled at 300o
C using recycle H2
quench. Here, the active sulphur is adsorbed. Reactor effluent vapour is cooled to 173o
C
using reactor fee/effluent heat exchangers where heat is exchanged with feed naphtha and
hydrogen mixture. Effluent along with wash water is cooled in reactor effluent air condenser
and reactor effluent trim cooler to 45o
C and sent separator. Here, it separates to
desulpurized naphtha and gases consisting of H2 and light hydrocarbons and water in water
boot. Gases from cold separator are mixed with make-up hydrogen, compressed and sent to
reactor. The desulphurized naphtha is sent to flash drum to remove light ends. Flashed
naphtha is then pumped to storage tanks.
REGENERATION SECTION
When one of the reactors is in regeneration mode, the reactor undergoes various processes.
First, it is depressurised because it is full of naphtha and hydrogen. It is depressurised to fuel
gas header and flare to 1.6 Kg/cm2
. Then, it is purged with by 99.9% nitrogen gas to bring
the H2 and hydrocarbons concentration to 2000 ppmw. After this combustion of coke and
sulphur is carried out in presence of N2 containing 0.2 to 1 % of oxygen by volume. It flows
in closed loop with the help of combustion recycle gas compressor. SO2, SO3, H2O and CO2
are produced and removed by SOR unit. At last, again the reactor is purged with nitrogen.
DESOX SECTION
During coke and sulphur combustion step of adsorbent regeneration, hot combustion product
at 450-480o
C from reactor will first exchange heat with circulating combustion air in
combustion air exchanger and then cooled in combustion air cooler and combustion air trim
cooler to 40o
C. Product gas is fed to caustic scrubber to remove SOX. Desired value of SOX
is 170 mg/Nm3
.
24

25. 25

26. SULPHUR RECOVERY UNIT
H2S removed in the HDT, DCU and INDMAX [process is sent to the sulphur recovery unit
(SRU) as acid gas. SRU recovers H2S as elemental sulphur through the Claus reaction.
Reactions occur in the two stages: Thermal stage (MCC) and 3 catalytic reaction stage. The
former consists of a high-performance burner, mixing chamber and heat removing boiler,
while the latter has two to three reactor stages. The sulphur recovery rate of the Claus
process is about 95 to 97%.
The tail gas that contains unrecovered sulphur is feed to the tail gas treating unit
(TGT).The recovered sulphur is stored in the sulphur pit and shipped as product after
undergoing a degassing process to remove H2S.The Claus process is an equilibrium
process, and a modified version of it with direct oxidation catalysts stored in the final stage
is called SUPERCLAUS .Since this improved process does not depend on Claus
equilibrium, it can attain a 99% recovery ratio without TGT.
SRU COMPONENTS
• CLAUS train based on combustion of acid gas coming from ARU (mine
regeneration unit) and SWS (sour water stripping unit).
• In tail gas coming from SRU and sweep gas coming from Sulphur pit are fed
to thermal incinerator to oxidise the residual H2S.
• The Flue gas leaving incinerator is discharged to atmosphere via a stack.
BRIEF DESCRIPTION
The feed consisting of sour gas and acid gas is mixed and is sent to main combustion
chamber (MCC). In MCC, burners are design to provide complete mixing of air and feed gas
for oxidation of all hydrocarbons, residual sulphur compounds and ammonia and a nominal
fuel gas. Then, it passes through a series of catalytic convertors where the SO2 and H2S react
to give elemental sulphur in presence of catalyst (activated Al oxide/ Ti oxide). After each
reactor bed, the mixture is passed through a heat exchanger to decrease the temperature as the
reaction is exothermic and gives better yield at lower temperature. Part of sulphur vapours
that converts to liquid is sent to steam jacketed vessel and the remaining gases are sent back
to the reactors for further reactions. This step is done 2 times and after coming out of the 3rd
bed and being sent to exchanger for cooling, the whole mixture is sent to steam jacketed
vessel. From the vessel, the gaseous phase is sent to incinerator for combustion of sulphur
and is sent into stack. The liquid sulphur is sent to underground steam jacketed vessels for
storage. If there some vapours in the underground vessel, then it is sent to incinerator.
26

27. 27

28. OIL MOVEMENT AND STORAGE DIVISION
OM & S division is a branch of production department. It was established on January 1,
1962. It is responsible for co-ordinating various activities with other agencies within and
outside the refinery. Oil India Limited supplies crude oil. The Oil Movement & Storage
(OM&S) and utility section cater to the storage and movement of crude oil and products
along with the provision of generating and distributing steam, power, air and other utilities.
The division has three sections:
• Receipt and blending section
• Dispatch section
• LPG section
The finished products are dispatched through tank trucks, tank wagons and Guwahati-Siliguri
and Guwahati-Betkuchi product pipeline. LPG is stored into bullets and Horton’s spheres.
FUNCTIONS OF OM&S
• Receipt, storage, accounting, preparation and supply of crude oil to CDU.
• Receipt and storage of intermediate and finished products from production unit.
• Blending of products and chemical dozing.
• Dispatch of finished products.
• Gauging and sampling of petroleum products.
• Maintaining central excise formalities.
• Recovery, preparation and supply of slop for reprocessing.
• Filling and dispatch of LPG in bulk dispatches in bullets mounted on trucks.
FINISHED PRODUCTS
• LPG
• Reformer Naphtha
• Motor spirit (MS)
• Kerosene
• Aviation Turbine Fuel (ATF)
• High-Speed Diesel Oil
• High-Speed Diesel Oil (low sulphur)
• High-Speed Diesel Oil (winter grade)
• Light Diesel Oil
• Raw Petroleum Coke
• Needle Coke
• Sulphur
28

29. EFFLUENT TREATMENT PLANT
Industries waste water treatment covers the mechanism and processes used to treat waters
that have been contaminated in some way by anthropogenic industrial or commercial
activities prior to its release into the environment or its reuse. Most industries produce
some wet waste although recent trends in the developed world have been to minimize such
production on recycle such waste within the production process. However, many industries
remain determined on process that processes that produce waste waters.
So, industries produce waste waters, otherwise known as effluent, as a by-product of their
production. The effluent contains several pollutants, which can be removed with the help
of an effluent treatment plant (ETP). The “clean” water can be safely discharged into the
environment.
IOCL-Guwahati Refinery has developed a modernised ETP for treatment of process
wastewater generated from various units of refinery as well as township.
Wastewater is collected in API separators and pumped to ETP and collected in Equalisation
tanks. Major pollutants are oil, grease, suspended solids, Biochemical oxygen demand
(BOD), chemical oxygen demand (COD), sulphides, phenols and cyanides etc.
BRIEF DESCRIPTION
Oil and grease are removed in API separators and Tilted Plate Interceptors (TPI) and
Dissolved Air Floatation (DAF) systems. Degradation of organic matter is carried out in
biological system comprising of activated sludge process designed in extended aeration
mode. The treated effluent is then sent for polishing to remove suspended solids, odour and
residual BOD and COD in pressure sand filters and activated carbon filters. Treated water
in then chlorinated and pumped to Brahmaputra river.
TREATED EFFLUENT CHARACTERISTICS:
PH 6.5-8.5
Oil <5ppm
Sulphide <0.25ppm
Phenol <0.35ppm
TSS <10ppm
BOD <7.5ppm
ETP SECTION:
SECTION 1
Physio-chemical Treatment for removal of hydrocarbons, sulphides and total suspended
solids.
29

30. SECTION 2
Biological treatment system in co-operating activated sludge systems for oxidising the
organic matter.
SECTION 3
Tertiary treatment system comprising of pressure sand filter and activated carbon filters for
treatment removal of TSS, odour, colour and phenol.
SECTION 4
Sludge processing section comprises of oily and chemical sludge processing and disposal as
a solid waste biodegradable material.
SECTION 5
Chemical dosing system comprises of storage facilities of various chemicals and
preparation of chemical solution of standard concentration for injection at various stage
during effluent treatment.
API SEPARATION:
Additional facility for separation of fuel oil from effluent and storage of waste oil effluent.
• Blow Down System
• Dehydrating Tanks
• Oil Settling Basin
• Emergency Reservoir
• Sanitary Water Basin
• Coke Fine Settler
• API Solid Removal System
API SOLID REMOVAL SYSTEM:
• Thickener
• Lagoons
CHEMISTRY OF EFFLUENT:
POLLUTANT TREATMENT METHOD
1) Free Oil 1) Gravity Separation
2) Emulsified Oil 2) Chem Destabilization and flotation
3) Sulphide 3) Chemical Oxidises
4) Organic (BOD/COD) 4) Biological Oxidation and
5) Settable Solids 5) Sedimentation
6) Microbes 6) Disinfection by Chlorination
7) Suspended Solids 7) Filtration
30

31. BIOLOGICAL TREATMENT:
BOD (food) + micro-organism = cellular matter + energy + CO2 +
H2O ACTIVATED SLUDGE PROCESS:
BOD + N + P + O2 + Bacteria = CO2 + H2O + energy + New bacteria
cells Dead bacteria cells + O2 = CO2 + H2O + N + P CHLORINATION:
• HYDROLYSIS REACTION
Cl2 + H2O ------------> HOCl + H+
+ Cl-
• IONIZATION REACTION:
HOCl --------------------> H+
+ OCl-
EQUIPMENTS
• FLASH MIXER: Breaking of oil emulsion and coagulate oil particles .It dose Acid
(HCl) whenever PH of effluent is required to be adjusted.
• FLOCCULATION: Provided to flocculate the coagulation formed in flash
mixing tank. Polyelectrolyte is added.
• AERATION TANK: Provide to remove biodegradable organics contributing to
BOD/COD.
• POLISHING SECTION: Pressure sand filter are provided to remove the suspended
solids and activated carbon filter are provided to remove the odour, colour and
organic compounds to meet the treated water quality (MINAS) for reverse in the
refinery.
• SLUDGE THICKENER: This unit is provided to increase consistency of sludge
for further treatment by centrifuge.
31

32. 32

33. DELAYED COKING UNIT
Delayed coking unit is a secondary processing unit designed and installed to process the low
value heavy stock to upgrade it to more valuable lighter and middle distillate with petroleum
coke as one of the products. The feed to be processed in the unit is Reduced Crude Oil
(RCO) obtained from bottom of the fractionating column of the CDU and the processed used
is Thermal Cracking.
The product separated out by fractionation of the cracked material are coker gases, coker
gasoline (CG), coker kerosene (CK), coker gas oil (CGO), coker fuel oil (CFO), Residual
fuel oil (RFO) and Raw Petroleum coke (RPC). Coker gasoline is disposed as part of feed to
INDMAX unit. While coker kerosene and coker gas oil is fed to Hydro Treating Unit to
remove Sulphur. RPC is disposed as finished product and coker gases as feed for LRU
conveyor belt carry the coke from coking chamber to coke yard and disposed with the help of
EOT crane.
The unit is called Delayed Coking Unit as the process envisages production of coke by
allowing high residence time (24 hours) for liquid phase cracking in the reaction chambers
operated in alternated days with a gap of 24 hours.
THEORY OF COKING
Heavier hydrocarbon (Reduced crude) is subject to high temperature (around 495o
C) to
crack the heavier ends for producing the lighter ends. At this temperature the larger
hydrocarbon molecules of high boiling ranges are thermally decomposed to smaller low
boiling molecules thereby producing lower boiling molecules thereby producing lower
boiling light and middle distillate such as Gas, Gasoline, Kerosene, Gas oil and at the same
rate. Some of the molecules which are reactive, combine with one another giving even larger
molecules than those present in the original stock forming Residual Fuel Oil and petroleum
coke. The phenomenon under which the above changes in the molecular structure of the
hydrocarbons take place, is known as Thermal Cracking.
CHEMICAL REACTIONS
There are three types of chemical reaction processes which occur continuously without any
distinct steps in the coking process:
• Dehydrogenation-The initial reaction is carbonization involves the loss of
hydrogen atom from an aromatic hydrocarbon and formation of aromatic free
radical intermediate.
• Rearrangement Reactions: Thermal rearrangement usually leads to formation of
more stabilized aromatic ring system which forms building block of graphite growth.
• Polymerization of aromatic radicals: Aromatic free radicals polymerized in the
process of coking reaction. The process is initiated in the liquid phase and
continued in different steps.
33

34. BRIEF DESCRIPTION
The feedstock is pumped by coker feed pumps from coker feed tanks located outside the
Battery limit, to the feed surge drum. Provision to receive hot short residue and remaining
streams from the unit, in the feed surge drum is kept.
The feed from the feed surge drum is pumped to Main Fractionator, under its level control,
by feed pumps. The feed is preheated in preheat exchanger using Kerosene product, Light
Diesel Oil (LDO) product and LDO circulating reflux (CR) respectively. The temperature at
the outlet of the preheat train is about 240C֯.
The preheated fresh feed is fed to the Main Fractionator bottom surge section. The mixed
stream offered and recycled in the weight ratio of 100:70 is fed to the two coker furnaces
by their respective fractionators bottom pumps.
The fractionators bottom material (fresh feed + recycle) at temperature of 315C֯-320C֯ is fed
to the two passes of each Coker Furnaces. Turbulising water is added to each pass after the
flow control valves. The water vaporizes and the effective volumetric flow inside the tube
increases so as to move the adherent HC liquid film in the tube walls faster. This minimizes
coke formation and increases heater run length.
The outlet of the convection section of the furnace goes to the top section of radiation
zone and finally comes out from the bottom most tube of radiation section. The fuel firing
in the heater is controlled by its outlet temperature. Either fuel gas or fuel oil can be
selected for control via selector switch. Fuel oil is atomized by Moderate Pressure (MP)
steam under differential pressure control.
Each furnace has two coke chambers (a cylindrical, insulated vessel). The feed inlet to
the coke chambers is from the bottom .The heated charge stock enters the bottom of the
coke chamber which is under the normal coking mode through the 4 way switch valves
.The vapours from the coke chambers are led from the top vapour outlet line to the
quench column.
Steam and water connections have been provided at the inlet of the coke chamber for steam
heating, pressure testing, steam stripping and water cooling in the coke chamber during
routine operations. Antifoam injection facilities are provided at the top of the coke chamber.
It helps in preventing/minimizing the boil over inside the coke chamber.
The flow from the furnace is alternated between the two coke chambers, to allow removal
of coke from one drum while the other is on-steam. Coking reaction continues to occur in
the coke chamber and the sensible heat of the incoming transfer fluid from the furnace
supplies the required reaction heat for coking in the coke chambers. Thus, the unvaporised
portion of the furnace effluent settles out in the coke chamber where the combined effect of
retention time and temperature causes the formation of coke.
The vapours pass on from the top of the chamber to the downstream quench column .LDO
quench has been provided immediately at the vapour outlet line of the coke chamber to
quench the vapours and minimize the coking and fouling in the overhead vapour line .The
bottom outlet line has two streams ,routed to respective circuits .Delayed coker drum
cycle length varies from unit to unit .However ,typically it is kept within 16 to 24 hours.
34

35. PRODUCTS OF DELAYED COKING:
• Delayed coker produces desirable liquid products (naphtha and gas oil) and by-
products and by-products coker gas and solid coke.
• Coker off-gas goes to the gas plate where C3 and C4 are recovered as LPG and the
lighter end can be used as fuel gas in the refinery.
• Naphtha contains high olefins content and this stream is usually sent to hydrotreater
for stabilization.
• Light Coker Gas Oil (LCGO) is sent to diesel hydrotreater for production of diesel
.Typical end point of this stream is around point of this stream is around 370C֯.
• Heavy Coker Gas Oil (HCGO) is sent to FCC/RFCC for production of valuable
distillate products .Typical end point of this stream is around 538C֯.
35

36. INDMAX
INDMAX is a high severity catalytic cracking process exclusively developed by IOC R&D
centre to produce very high yield of LPG from various hydrocarbon fractions namely,
naphtha to residues. The process employs proprietary catalyst formulations having
excellent metal tolerance with coke and dry gas selectively. The operating conditions of the
units are such that the liquid hydrocarbon products are selectively over cracked to LPG
containing fractions of C3-C4 olefins without proportionate increase in dry gas and coke.
Process is similar to that of conventional Fluidized Catalytic Cracking (FCC) with major
difference in catalyst to oil ratio, operating conditions, catalyst formulation and catalyst
make-up rate.
• Operation reaction temperature: 530-600o
C
• Catalyst to oil ratio: 15-25 (wt./wt.)
• Riser steam: 10-15 wt. % of feed
SALIENT FEATURES
It is high severity Fluidized Catalytic Cracking process in which high molecular weight
components are cracked to LPG range products.
• High yield of LPG (40-65 wt. % of feed)
• Very high catalyst to oil ratio coupled with high reactor temperature for severe
cracking
• Wide flexibility in fed stock (naphtha to heavy residue)
• Novel catalyst formulation (IMX-50) for high yield of LPG, low coke, low dry gas
and very high Vanadium tolerance.
INDMAX COMPONENT:
• Component A: Medium pore pentasil zeolite
• Component B: consists of partially or fully ultra-stabilized Y-zeolite with
specified rare earth metals, active silica-alumina based matrix and binder.
• Component C: Mostly contain large pore/mesoporous acidic non-crystalline active
matrix.
36

37. PROCESS OUTLINE:
• Feed storage and pumping section
• Reactor and Regenerator section
• Fractionation section
• Gas concentration section
• LPG/Gasoline treatment section
ADVANTAGES OF INDMAX TECHNOLOGY:
• Up gradation of low value heavy hydrocarbon into high value LPG and high octane
distillates.
• Can process feedstock with CCR level of 5.0 wt%.
• Catalyst can withstand the high metal level in the feed specially vanadium.
• Process is economical and gives better return on investment.
37

38. MOTOR SPIRIT QUALITY UPGRADATION UNIT
MSQU unit consists of three cut splitter, SR light naphtha splitter, naphtha hydrotreater
unit and isomerisation unit.
OBJECTIVE OF UNITS
• 3 CUT SPLITTER: to split INDMAX gasoline and wild naphtha and separate a heart
cut stream.
• NSU: to produce light naphtha with reduced C7+ contents from feed of SR naphtha
from existing splitter.
• NHDT: to treat mixture of light naphtha heart cut from the 3 cut splitter and SR light
naphtha in order to produce a sulphur free stabilised naphtha to feed ISOM (less than
0.5 wt. ppm sulphur and less than 0.1 wt. ppm N2).
• ISOM: to increase RON of hydrotreated light naphtha cut.
NAPHTHA SPLITTER UNIT
The purpose of the new SR light naphtha splitter column is to reduce the C7+ hydrocarbon
compound contents to maximize in light naphtha to NHDT unit. Light naphtha from the top
of new SR LN splitter column along with heart cut from 3 cut splitter column will be routed
to NHDT as feed.
• Process Licensor: M/s Lurgi, India
• Design Capacity: 67 TMTPA
• Turndown: 50%
OPERATION
SR light naphtha (LN) (C5-90o
C cut) from existing splitter column (C-001) is routed to
naphtha splitter feed surge drum (V-51) by flow control at 40o
C. From feed surge drum,
the SRLN is pumped under level/flow control by naphtha splitter feed pumps (P-51)
through naphtha splitter feed/bottom heat exchanger. The feed is preheated by exchanging
heat with naphtha splitter bottoms. The heated feed at 63.1o
C enter naphtha splitter on tray
31. The pressure on top and bottom of the column is 1.5 and 1.9 Kg/cm2
g respectively. The
splitter has 45 trays in the column. The reboiler works as a thermosyphon reboiler and used
MP steam as a reboiling media.
The column overheads at 98.8o
C are fully condensed in air cooler (AC-51). The condensed
vapours are collected in naphtha splitter reflux drum. a part of liquid is sent as reflux to
splitter column by flow control via naphtha splitter reflux pump. Other part is sent under flow
control/level control to ISOM block and feed tank as NHDT feed naphtha after cooling upto
40o
C in light naphtha trim cooler. Excess naphtha is routed to new NHDT feed tank and
existing HGU feed tank by level controllers operated by selector switch. The bottom of
naphtha splitter called heavy LN is pumped by naphtha splitter bottom pump after
exchanging heat in naphtha splitter feed/bottom heat exchanger. Further heavy LN is cooled
in the heavy LN trim cooler 53o
C up to 40o
C and sent to existing HGU feed tanks along with
excess NHDT naphtha from naphtha splitter bottoms pumps.
38

39. NAPHTHA HYDROTREATER UNIT
The purpose of light naphtha hydrotreater unit is to produce a clean desulphurized naphtha cut
to be processed in ISOM unit after removal of all impurities which are currently poisons for
catalyst (sulphur, nitrogen, water, halogens, diolefins, olefins, As, Hg and other metals).
Treating process occurs by passing naphtha over a fixed bimetallic catalyst bed in an
adiabatic reactor in the presence of hydrogen. There are 2 fundamental reactions that
occur. They are hydrorefining and hydrogenation.
HYDROREFINING
• Desulphurization: sulphides, disulphides, mercaptans readily react with saturated
or aromatic compounds to give H2S.
RSR’ + 2 H2
→
RH + R’H + H2S
RSSR’ + 3 H2
→ RH + R’H + 2 H2S
RSH + H2
→ RH + H2S
• Denitrification: it has lower reaction rate than desulphurization. Nitrogen I
released in the form of ammonia.
R-NH2 + H2
→
RH + NH3
HYDROGENATION
This refers to saturation of olefins and diolefins if present in feed. Reaction occurs readily in
the top portion of catalytic bed releasing exothermic heat and consume H2.
39

40. C7H14 + H2
→
C7H16
C8H14 + 2 H2
→
C8H18
Minimal hydrogenation of aromatics occurs less than 1%. This is the consequence of high
selectivity of AXENS bimetallic catalyst.
Elimination of As and other metals: As and metals are present in organometallic form. After
hydrogenation in reactor, hydrogenated form reacts with hydrotreater catalyst forming a
bimetallic compound. As a result, As and other metals are physically adsorbed by catalyst
creating a gradient on catalyst bed.
During operation cycle, the equilibrium level contaminants will progressively move down the
bed. It is good operating practice to analyse and replace this top portion of catalyst bed as
necessary to prevent contaminant breakthrough into the isomerization feed.
CATALYST CHARACTERISTICS OF NHDT
Two catalyst are used in hydrotreatment unit:
• HR-945 (1st
bed of reactor) for the olefins hydrogenation. They are used in front
of hydrotreatment catalysts to protect them against deactivation by unsaturated
compounds contained in cracked stock from INDMAX. It limits the
polymerisation of olefins and diolefins and thus, coke formation even at low
hydrogen partial pressure.
• HR-538 (2nd
bed of the reactor) for desulphurization and denitrification. It
presents very high denitrification activity and superior desulphurisation activity.
It’s features are particularly interested in treatment of feedstock originated from
thermal, catalytic conversion processes as well as FCC feed pretreatment.
Catalysts used are bimetallic catalysts consisting of nickel and molybdenum dispersed
on high surface area alumina support. The Ni-Mo catalyst can require temperature up
to 5o
C higher than that of Co-Mo for the same desulphurization efficiency. However,
Ni-Mo is a better denitrification catalyst than Co-Mo and is typically the catalyst of
choice when treating cracked feedstock with relatively higher nitrogen contents.
Main features of hydrotreating catalysts:
• High purity alumina support having a strong resistance to attrition.
• High stability and selectivity towards the desirable hydrotreating reactions, ease of
regenerability.
PROCESS FLOW DESCRIPTION
Feed consisting of SRLN from naphtha splitter and heart cut from tank, enters at battery limit
(4 Kg/cm2
g and 40o
C for both) and are directed to HDT feed surge drum. Feed is mixed
with liquid recycle of olefin dilution before entering the reaction circuit. It is then mixed with
the mixture of hydrogen rich recycle gas, coming from the HDT recycle gas compressors and
make-up hydrogen, coming from the ISOM unit. This mixture is then preheated in the
reactor feed/effluent exchangers (E-01A/B/C shell side) and further heated to the required
temperature in the reactor feed heater(F-01) before entering the HDT reactor (R-01).
40

41. Hydrotreating is performed in two steps: the first step consists of olefins and diolefins
hydrogenation, performed in the first bed of the HDT reactor, and the second one
corresponds to desulphurization and denitrification, which takes place in the second bed of
the HDT reactor. The reactor inlet temperature is controlled by regulating fuel gas flowrate
to the burners. This temperature varies from 250o
C (SOR) to 270 o
C (EOR) depending upon
the position in the catalyst cycle. The temperature increase in the HDT reactor is mainly due
to olefin hydrogenation. A liquid quench is required at the outlet of the first bed to cool down
the temperature from 295o
C or 315o
C depending on the position of the cycle.
The reactor effluent is then cooled down and partially condensed in the NDT feed/effluent
heat exchangers (tube side) and in the HDT reactor effluent air cooler (AC-01) and in the
HDT reactor effluent trim cooler (E-02). The 2-phase mixture is then separated in the HDT
separator drum (V-02). The vapour phase coming from separator is used to recycle and
mixed with hydrogen make-up coming from the ISOM. The mixture is then routed through
the HDT compressor knock out drum to the suction of the HDT recycle gas compressors (K-
01). A small part of the recycle gas can be purged to the flare. This purge is used to increase
the recycle gas purity during operation and to control the reaction section pressure during
start-up.
Water is recovered in the boot of the separator drum. the main part is recycled by HDT water
recycle pumps (P-04) and under flow control, mixed with boiler feed water (BFW) make-up, the
other part is routed to underwater level control to the sour water stripping section.
The separated liquid hydrocarbon phase is split into 3 parts. A part is routed under flow
control with level reset to the stripper section. Another part is recycled by pump P-03 and,
under flow control, mixed with the feed to dilute the olefins. The last part is pumped by P-03
and injected under temperature/flow control at the inlet of the second bed of the reactor as
liquid quench.
In the stripper section, the raw hydro treated naphtha is heated in the first and second HDT
stripper feed/bottom heat exchangers (E-06 shell side) to enter the HDT stripper (C-01) on
10th
tray at around 126o
C. this column is reboiled by the HDT stripper reboiler (E-04)
with intermediate pressure steam (IS).
Column overheads are partially condensed in HDT stripper air cooler (AC-02) and HDT
stripper overhead trim cooler (E-05) and then collected in the HDT stripper reflux drum (V-
05). The overhead vapour from the reflux drum is routed under pressure control to the ISOM
off-gases make-up compressors via off-gases make-up knock out drum.
The liquid phase from the reflux drum is pumped by the HDT stripper reflux pumps (P-05)
under flow control with level reset to the stripper column as reflux. The stripper bottom
product is cooled down in the first and second stripper feed/bottom exchangers (E-06 tube
side) and the in the hydro treated product cooler (E-07).
A sulphur guard bed (V-04) is provided between the 2 shells of E-06 in order to protect the
isomerization catalysts from stripper misoperations and potential sulphur breakthrough. The
desulphurised naphtha is routed to the ISOM under flow control reset by level of the stripper.
41

42. 42

43. ISOMERIZATION UNIT
Isomerization of light hydrotreated naphtha is carried out in a series of 2 fixed bed reactors.
The 3rd
bed is provided for benzene hydrogenation.
Isomerization is the conversion of hydrocarbons to their isomers which have the same
molecular formula but different arrangement of molecules. The C5/C6 isomerization section
specifically converts the normal C5/C6 paraffins to their isomers that is to a higher octane
number over a proprietary Pt catalyst in the presence of H2. The conversion of normal
paraffins to the isomers is determined by the reaction equilibrium at the reactor operating
conditions. The low octane methyl-pentanes and the unconverted n-hexane are recycled back
to isomerisation reactors to achieve the objective of RON clear 87 minimum.
DUTY OF UNIT
Isomerization is the conversion of low octane straight chain compounds to their higher
octane branched isomers. The light hydrodesulphurised naphtha feed is dried and passes over
an activated chloride catalyst in presence of over through H2 (also dried). The reactor
temperature is kept low in the range of 120-160o
C taking advantage of higher equilibrium
concentration of isomerization at lower temperature and minimizing hydrocracking. Reaction
required to be done at a very low partial pressure of H2.
A deisohexanizer tower is included to recycle the low octane C6 n-paraffins and methyl
pentanes back to the reactor circuit to obtain a high octane product.
CHEMICALS REACTIONS
There are principally two fundamental reactions occurring:
• Benzene hydrogenation: benzene and hydrogen react to form cyclohexane. This
reaction occurs in the first reactor R-11. Benzene hydrogenation is an exothermic
reaction (16800 kcal/kmol of consumed hydrogen).
C6H6 + 3 H2
→
C6H12
• Isomerization: it is the conversion or rearrangement of the structure of a compound to
its more branched, higher octane structure. These rearrangements are depicted by the
following formula:
n-pentane (RON=62)
→
isopentane (RON=93)
These reactions are reversible and the final distribution of the isomers is based on
the isomers is based on the equilibrium composition which is dictated by the reactor
process conditions and kinetics.
• Naphthenes ring opening: the 3 naphthenes which are typically present in an
isomerization feed are cyclopentane (CP), methyl cyclopentane (MCP) and
cyclohexane (CH). These naphthenic rings break and hydrogenate to form paraffins.
Ring opening reactions increase with increasing temperature and again are
governed by equilibrium compositions as the reactor process conditions. At typical
isomerization reactor conditions the conversion of naphthene rings to paraffins will
be approximately 20-30 %.
Naphthenic or cyclic components tends to inhibit the isomerization reactions and are
therefore undesirable in large quantities. The cyclic components are absorbed on the
catalyst and reduce the active sited available for paraffin isomerization. They also
43

44. consume hydrogen, produce exothermic heat which is undesirable from the
isomerization equilibrium standpoint. However undesirable as they are, they are the
natural fraction of C5/C6 cut naphtha and are difficult to eliminate without also
eliminating other desirable components.
• Hydrocracking: operating at the low severity reactor conditions, very C5/C6
hydrocracking occurs in the isomerization reactors. C7 paraffins however hydrocrack
readily to produce C3 and C4 components. Much of the hydrocracking occurs in the
first reactor which typically operates at a higher temperature. Hydrocracking
reactions consume hydrogen, and hence it is recommended to restrict C7+ contents of
the feedstock.
C7H16 + H2
→
C3H8 + C4H10L
CATALYSTS
The benzene hydrogenation catalyst (R-11) is LD412R. It is a platinum on alumina
hydrogenation catalyst used to hydrogenate benzene contained in the isomerization feedstock.
The isomerization catalyst (R-12 and R-13) reference is ATIS-2L. it is a platinum
on chlorinated alumina-based catalyst.
Catalyst contaminants
The isomerization catalyst is highly sensitive to the following contaminants:
Sulphur, water/oxygenates, nitrogen, fluoride.
PROCESS DESCRIPTION
Isomerization of the light hydrotreated naphtha is carried out in series of 2 fixed bed reactors.
The unit consists of following sections:
• Feed Dryers and Hydrogen Dryers
• Reactors
• Stabilizer
• Deisohexanizer
• Caustic Scrubber
• Dryer Regeneration
• Chloride Injection Facility
DRYERS SECTION
Light hydrotreated naphtha from HDT unit and deisohexanizer recycle product are mixed in
feed surge drum (V-13). Naphtha is then pumped by P-11 pumps to enter down flow the 2
feed dryers (V-14) in series in order to protect the isomerization catalyst from irreversible
damage with water, which is extremely poisonous to the reactor catalyst. Light hydrotreated
naphtha to the reaction section is flow controlled. The make-up hydrogen gas from the PSA
unit also needs to pass through chloride guard bed (V-11) to remove water and potential HCl
before being dried to remove water and CO/CO2 which are extremely poisonous to the
reactor catalyst. Hydrogen from battery limit goes to chloride guard bed then to H2 make-up
knock out drum (V-12). It is compressed to the desired pressure level by compressors and
cooled in exchanger E-11. Then, under pressure control, part is sent to HDT unit and
44

45. remaining part is sent to dryers in series. It is mixed with dried naphtha and sent to
isomerization reaction section.
ISOMERIZATION REACTION SECTION
The combined 2 phase feed from the dryer section is preheated in deisohexanizer
recycle/reactors feed exchanger (E-12) at EOR only, in first stage reactor/effluent exchanger
(E-13) and in hydrogenation reactor feed/effluent exchanger (E-14). Finally, reactor feed is
heated with medium pressure steam to required reactor inlet temperature by hydrogenation
reactor feed heater (E-15).
Feed enters the benzene hydrogenation reactor (R-11) where the benzene is hydrogenated.
The reaction of hydrogenation is highly exothermic. The inlet temperature of the first
isomerization reactor (R-12) is controlled by hydrogenation reactor feed/effluent exchanger
(E-14) by-pass.
A small amount of chloriding agent is continuously injected into the first stage isomerization
reactor feed by pump P-19 in order to maintain the chloride balance on the isomerization
catalyst. This is a make-up for catalyst chloride, which is lost in reactor effluent.
Hydrogenated feed is routed to first stage isomerization reactor R-12, where isomerization
reactions occur. These reactions are slightly exothermic. The reactor effluent, that leaves the
first isomerization reactor, has to be cooled in E-13 tube side before entering the second
stage isomerization reactor R-13. In R-13, remaining isomerization occurs.
Both 1st
and 2nd
stage isomerization reactors are mixed phase, down-flow reactors, with a
single catalyst bed. The isomerization reactors are designed to operate in the lead/tail
position or in a single reactor configuration. The reactor circuit pressure is controlled using a
back pressure controlled located on the reactor effluent stream, routed to stabilizer (C-11).
STABILIZER SECTION
Isomerization reactor effluent feeds the stabilizer column on tray 15 of the 32 trays. The
stabilizer purpose is to reduce C4 rate in the isomerization reactor effluent. LPG, H2 and HCl
are stripped and sent to caustic scrubber column (C-13). The stabilizer operating pressure is
optimized to strip out the C4 components from the effluent, while minimizing the C5
hydrocarbon vent losses and reducing C4 content of the isomerate product.
The stabilizer overhead is partially condensed in stabilizer air cooler (AC-11) and the
stabilizer trim cooler (E-17). It is collected in the stabilizer reflux drum (V-17) where the
vapour phase is routed under pressure control to the scrubber section and liquid is pumped by
pump P-12 to the stabilizer as reflux.
Stabilizer is reboiled with IS in stabilizer reboiler (E-16). Stabilizer’s bottom is routed to
deisohexanizer (C-12) via stabilizer bottom chloride guard bed (V-16) in order to avoid
chloride presence in the rest of the unit and potential adsorbent damage or product pollution.
DEISOHEXANIZER
Deisohexanizer (DIH) is fed with stabilizer bottom. DIH recovers isomerate product and
recycles low octane methyl-pentanes and n-hexanes to the reactors. The isomerization
recycle is withdrawn to DIH recycle drum (V-19). Liquid is pumped by isomerization
45

46. recycle pumps (P-15), part is recycled to the reactor section after being cooled successively
against the deisohexanizer recycle/reactors exchanger (E-12) and the recycle tri, cooler (E-
22), the other part of the DIH side is draw is heated and vaporized against DIH feed/pump
around exchanger in E-21.
Overhead vapour of the column is totally condensed through DIH air cooler (AC-12) and is
routed to deisohexanizer reflux drum (V-18). From here, light isomerate is pumped out (P-
13). Part of light isomerate is sent under flow control to C-12 as reflux. The remaining part is
sent under level/flow control to light isomerate cooler (E-19). A small amount is used as
regenerant for dryers (batch operation). DIH is reboiled with MP steam in DIH reboiler E-18.
The bottom stream is pumped by deisohexanizer bottom pumps (P-14). This stream,
concentrated in C7+ and C6 naphthenes is cooled in heavy isomerate cooler (E-20) and is
mixed with light isomerate before being sent to isomerate storage.
SCRUBBER SECTION
As the off-gas from the stabilizer reflux drum overhead contain HCl, it must be caustic
treated and water washed before being released. This off-gas enters in the bottom of the
column C-13 and goes up through caustic hold-up in a first packed bed. The gas leaving the
caustic wash section, saturated by caustic, is again washed with BFW in the top packed
section, to remove any entrained caustic. Then the off-gas is routed under pressure control to
the LPG recovery unit or flare.
DRYERS REGENERATION
Light naphtha feed, H2 make-up flow through their respective dryers that are operated in
series. Molecular sieves become saturated after a certain period of time. Then, they need
regeneration. A multicell on line moisture analyzer are used to monitor the moisture content
of the streams leaving each dryer.
Both the feed and hydrogen dryers are regenerated using vaporized deisohexanizer distillate
product as the regenerant medium in order to remove the water trapped by the molecular
sieves. The concerned dryer is isolated from the other one which is still in service.
The regenerant is supplied from light isomerate pumps (P-13) and is completely vaporized
by medium pressure steam in dryer regenerant vaporizer (E-24). The vaporizer consists of a
vertical shell with bayonet-type tubes. Liquid level in the vaporizer is monitored closely to
avoid liquid carryover to dryer regeneration superheater (F-11 electric heater).
The vapor is then superheated up to 310o
C in dryer regeneration superheater (F-11).
Superheated vaporized isomerate flows through the dryer being regenerated.
The hot vapour leaving the dryer is condensed in dryer regenerant air cooler (AC-13).
After passing through the dryer regenerant degasser (V-20), the regenerant steam is mixed
under pressure control with the isomerate to be sent to light isomerate cooler and to
isomerate storage.
46

47. The regenerant degasser is a liquid flooded drum, releasing the effluent regenerant liquid on
pressure control for mixing with the isomerate product. Any light components which
accumulate in the regenerant degasser are purged to flare under a liquid level controller. Free
water collected at the bottom of the regenerant degasser is periodically drained to oily water
sewer.
47

48. 48

49. PROJECT
FURNACE
A furnace is essentially a thermal enclosure and is employed to process raw materials at high
temperatures both in solid state and liquid state. Several industries like iron and steel making,
non-ferrous metals production, glass making, manufacturing, ceramic processing, calcination
in cement production etc. employ furnace. The principle objectives are a) To utilize heat
efficiently so that losses are minimum, and b) To handle the different phases (solid, liquid or
gaseous) moving at different velocities for different times and temperatures such that erosion
and corrosion of the refractory are minimum.
Characteristics of an Efficient Furnace
Furnace should be designed so that in a given time, as much of material as possible can be
heated to uniform temperature as possible with the least possible fuel and labour. To achieve
this end, the following parameters can be considered.
• Determination of the quantity of heat to be imparted to the material or charge.
• Liberation of sufficient heat within the furnace to heat the stock and overcome all heat
losses.
• Transfer of available part of that heat from the furnace gases to the surface of the
heating stock.
• Equalisation of the temperature within the stock.
• Reduction of heat losses from the furnace to the minimum possible extent.
Heat Transfer in Furnaces
The main ways in which heat is transferred to the steel in a reheating furnace are shown in
The figure below. In simple terms, heat is transferred to the stock by:
• Radiation from the flame, hot combustion products and the furnace walls and roof.
• Convection due to the movement of hot gases over the stock surface
At the high temperatures employed in reheating furnaces, the dominant mode of heat transfer
is wall radiation. Heat transfer by gas radiation is dependent on the gas composition (mainly
the carbon dioxide and water vapour concentrations), the temperature and the geometry of
the furnace.
49

50. PERFORMANCE EVALUATION OF A TYPICAL FURNACE
Thermal efficiency of process heating equipment, such as furnaces, ovens, heaters, and kilns
is the ratio of heat delivered to a material and heat supplied to the heating equipment. The
purpose of a heating process is to introduce a certain amount of thermal energy into a
product, raising it to a certain temperature to prepare it for additional processing or change
its properties. To carry this out, the product is heated in a furnace. This results in energy
losses in different areas and forms. For most heating equipment, a large amount of the heat
supplied is wasted in the form of exhaust gases.
These furnace losses include:
• Heat storage in the furnace structure
• Losses from the furnace outside walls or structure
• Heat transported out of the furnace by the load conveyors, fixtures, trays, etc.
• Radiation losses from openings, hot exposed parts, etc.
• Heat carried by the cold air infiltration into the furnace
• Heat carried by the excess air used in the burners.
Stored Heat Loss:
First, the metal structure and insulation of the furnace must be heated so their interior
surfaces are about the same temperature as the product they contain. This stored heat is held
in the structure until the furnace shuts down, then it leaks out into the surrounding area. The
more frequently the furnace is cycled from cold to hot and back to cold again, the more
frequently this stored heat must be replaced. Fuel is consumed with no useful output.
Wall losses:
Additional heat losses take place while the furnace is in production. Wall or transmission losses
are caused by the conduction of heat through the walls, roof, and floor of the heating device.
Once that heat reaches the outer skin of the furnace and radiates to the surrounding area or is
carried away by air currents, it must be replaced by an equal amount taken from the combustion
gases. This process continues as long as the furnace is at an elevated temperature.
Material Handling Losses:
Many furnaces use equipment to convey the work into and out of the heating chamber, and
this can also lead to heat losses. Conveyor belts or product hangers that enter the heating
chamber cold and leave it at higher temperatures drain energy from the combustion gases. In
car bottom furnaces, the hot car structure gives off heat to the room each time it rolls out of
50

51. the furnace to load or remove work. This lost energy must be replaced when the car
is returned to the furnace.
Cooling Media Losses:
Water or air cooling protects rolls, bearings, and doors in hot furnace environments, but at the
cost of lost energy. These components and their cooling media (water, air, etc.) become the
conduit for additional heat losses from the furnace. Maintaining an adequate flow of cooling
media is essential, but it might be possible to insulate the furnace and load from some of
these losses.
Radiation (Opening) Losses
Furnaces and ovens operating at temperatures above 540°C might have significant radiation
Losses. Hot surfaces radiate energy to nearby colder surfaces, and the rate of heat transfer
increases with the fourth power of the surface's absolute temperature. Anywhere or anytime
there is an opening in the furnace enclosure, heat is lost by radiation, often at a rapid rate.
Waste-gas Losses
Waste-gas loss, also known as flue gas or stack loss, is made up of the heat that cannot
be removed from the combustion gases inside the furnace. The reason is heat flows from
the higher temperature source to the lower temperature heat receiver.
Air Infiltration
Excess air does not necessarily enter the furnace as part of the combustion air supply. It
can also infiltrate from the surrounding room if there is a negative pressure in the furnace.
Because of the draft effect of hot furnace stacks, negative pressures are fairly common, and
cold air slips past leaky door seals, cracks and other openings in the furnace. Every time
the door is opened, considerable amount of heat is lost. Economy in fuel can be achieved if
the total heat that can be passed on to the stock is as large as possible.
CALCULATION OF FURNACE EFFICIENCY
Example: Furnace Efficiency Calculation for a Typical Reheating Furnace An oil-fired
reheating furnace has an operating temperature of around 350°C. Average fuel consumption
is 1tonne/hour. The flue gas exit temperature is 155 °C after air preheater. Air is preheated
from ambient temperature of 20 °C to 180 °C through an air pre-heater. The furnace has 460
mm thick wall (x) on the billet extraction outlet side, which is 1 m high (D) and 1 m wide.
The other data are as given below. Find out the efficiency of the furnace by both indirect and
direct method.
Exit flue gas temperature=155°C
Ambient temperature = 20°C
Preheated air temperature=180°C
Specific gravity of oil= 0.92
Average fuel oil consumption= 1tonne/hr
Calorific value of oil=10000kcal/kg
Average O2 percentage in flue gas =5%
51

52. Weight of stock=150 m^3/hr
Specific gravity of stock= 0.87
Specific heat of stock=0.69 kCal/kg/°C
Average surface temperature of heating + soaking zone=122°C
Average surface temperature of area other than heating and soaking
zone=80°C Area of heating + soaking zone= 70.18 m2
Area other than heating and soaking zone = 12.6 m2
Solution
INDIRECT METHOD
1. Sensible Heat Loss in Flue Gas:
Excess air = (O2%)/(21%-O2%)*100
= 31.25%
Theoretical air required to burn 1 kg of oil = 14 kg
Total air supplied = 14 x 1.31 kg / kg of oil =18.34 kg / kg of oil
Total mass (m)= Weight of flue gas (Air +fuel) = (18.34+1)=19.34 kg / kg of
oil Sensible heat loss = m x Cp × ∆T
Cp = Specific heat; ∆T= Temperature
Sensible Heat loss = 19.34*0.24*133=616.05 kCal / kg of oil
% Heat Loss in Flue Gas = (616.05)*100/10000 = 6.16%
2. Loss Due to Evaporation of Moisture Present in Fuel:
% Heat Loss = (M*(584+ Cp(Tfg- Tamb)) *100 )/ GCV of fuel
Where,
M = kg of Moisture in 1 kg of fuel oil (0.15 kg/kg of fuel oil)
Tfg = Flue Gas Temperature, °C
Tamb = Ambient Temperature,°C
GCV = Gross Calorific Value of Fuel, kCal/kg
% Heat Loss = 0.15*(584+0.45(130))*100/10000 =0.9637%
52

53. 3. Loss Due to Evaporation of Water Formed due to Hydrogen in Fuel:
% Heat Loss = (9+H2*(584+ Cp(Tfg - Tamb)) *100 )/ GCV of fuel
Where,
H2 = kg of H2 in 1 kg of fuel oil (0.1123 kg/kg of fuel oil)
% Heat Loss = (9+0.1123*(584+0.45*130))*100)/10000 = 6.49%
S
4. Heat Loss due to Openings:
If a furnace body has an opening on it, the heat in the furnace escapes to the outside as
radiant heat. Heat loss due to openings can be calculated by computing black body radiation
at furnace temperature, and multiplying these values with emissivity (usually 0.8 for furnace
brick work), and the factor of radiation through openings.
The shape of the opening is square and D/X = 1/0.46 = 2.17
The factor of radiation = 0.71
Black body radiation corresponding to 350°C = 36.00
kCal/cm2/hr Area of opening = 100 cm * 100 cm = 10000 cm2
Emissivity = 0.80
Total heat loss = 36 * 10000 * 0.71 * 0.8 = 204480 kCal/hr
Equivalent fuel oil loss = 20.45 kg/hr
% of heat loss through openings = 20.45*100/1000
=2.045% 5. Heat Loss through Furnace Skin:
a. Heat loss through roof and sidewalls:
Total average surface temperature = 122°C
Heat loss at 122 °C = 1252 kCal / m2 / hr
Total area of heating + soaking zone = 70.18 m2
Total heat loss = 1252 kCal / m2 / hr x 70.18 m2 = 87865 kCal/hr
Equivalent oil loss (a) = 8.78 kg / hr
b. Total average surface temperature of = 80°C
Area other than heating and soaking zone = 740 kCal / m2 / hr
Heat loss at 80°C = 740 kCal / m2 / hr x 12.6 m2 = 9324 kCal/hr
Equivalent oil loss (b) = 0.93 kg / hr
Total loss of fuel oil = a + b = 9.71 kg/hr
53

54. Total percentage loss = 9.71 * 100 / 1000 = 0.971%
Combined percentage loss = (6.16+0.9637+6.49+2.045+0.971)%=16.62%
Efficiency of Furnace =100%-16.62%=83.37%
DIRECT METHOD
Heat input = 1000kg/hr
Heat output =m * Cp * ∆T =150*0.87*1000*0.69*(350-260) = 8104050kCal
Efficiency = Heat in the stock/Heat in the fuel consumed for heating the stock
=8104050*100/(1000*10000) = 81.04%
54

55. CONCLUSION
After the completion of industrial training, we enhanced compentencies & competitiveness
in our respective area of specialization. We tried to relate the experience in the workplace
with knowledge learned in the institute & applied on the job under supervision.
Here, we gained the experience and knowledge that can be used for suitable job without
delay after studies.
We learned to hone soft skills appropriate to the work environment. Also get improvised in
communication skills. We assessed career ability, knowledge & confidence as well as
enhanced our marketability to be more competitive.
With experience, knowledge & skills acquired during industrial training, we will be better
prepared to face working world.
55

56. BIBLIOGRAPHY
• IOCL OPERATION MANUALS
• WWW.WIKIPEDIA.COM
• IOCL WEBSITE
56