REPORT ON VIZAG STEEL

1. PROJECT REPORT ON BENZOL RECOVERY
PLANT
Submitted in partial fulfilment of the requirements for the award of degree of
BACHELOR OF TECHNOLOGY
IN
CHEMICAL ENGINEERING
Submitted By:
KUMARCHAND BEHERA
112CH0070
N I T ROURKELA
(2ND
JUNE 2014 – 28TH
JUNE 2014)
COKE OVENS AND COAL CHEMICAL PLANT
SUBMITTED BY:
KUMARCHANDBEHERA
112CH0070

2. CERTIFICATE
I hereby certify that Kumar chand behera, (112CH0070) of National
Institute of Technology, Rourkela (Odisha), has undergone Project from
02-06-2014 to 28-06-2014 at our organisation to fulfil the requirements
for the award of degree of B.Tech. Of branch Chemical Engineering. He
worked on Optimization of Benzol Plant project during this period
under the supervision of Mr. G.Venkata Rao, AGM (Operation). During
his tenure with us we found him sincere and hard working. We wish
him a great success in the future.
Dated: Project In-charge:

3. ACKNOWLEDGEMENTS
A summer project is a golden opportunity for learning and self
development. I consider myself very lucky and honoured to have so many
wonderful people leadme throughin completionof this project.
My grateful thanks to Mr. G.VENKATA RAO, AGM (Operation) who in
spite of being extraordinarily busy with his duties, took time out to hear, guide
and keep me on the correct path. I do not know where I would have been
without him. A humble ‘Thank you’ Sir.
Mr. M. GANESH BABU, HR Department monitored my progress and
arranged all facilities to make life easier. I choose this moment to acknowledge
his contributiongratefully.
Prof. R.K.SINGH, HOD (Chemical department, NIT Rourkela) whose
patience I have probably tested to the limit. He was always so involved in the
entire process, shared his knowledge, and encouraged me to think. Thank you,
Dear Sir.
I would like to thanks for his efforts and help provided to me to get such an
excellentopportunity.
Last but not the least there were so many who shared valuable information
that helpedin the successful completionof this project.
KUMAR CHAND BEHERA

4. ABSTRACT
Iron and steel making technology, including the preparation of raw
materials and utilisation of wastes, has undergone marked changes over the
last years. The hand mining of ores/minerals has almost completely been
replaced by mechanised mining. The role of mineral beneficiation and sizing
has therefore increased. The current emphasis is on maximising the use of
mined materials through multiple beneficiation stages and agglomeration of
fines.
Whilst emerging technologies for producing liquid iron are making their
advent, blast furnaces continue to be the unchallenged source of hot metal
production. However, the efficiency of iron making, both in terms of
productivity and quality of hot metal has improved markedly.
Gone are the days of open hearth furnaces and Bessemer converters. LD
steelmaking has incorporated in it a number of improvements, namely
combined blowing, dynamic control along with the use of the sub lance,
improved refractory’s for lining and ladle treatment of liquid steel.
Trends emerging in the area of steel-casting include, horizontal casting,
thin strip casting and hot charging of con-cast products without soaking/re-
heating.
The paper deals with some of these areas including the advances in
Benzol plant in the recoverysection.

5. CONTENTS
I. INTRODUCTION
 VISAKHAPATNAMSTEEL PLANT
 VSP’S FRUITFUL ACHIEVEMENTS
II. MODERN TECHNOLOGY AND MAJOR PLANT FACILITIES
 THE MODERN TECHNOLOGY
 THE MAJOR PLANTFACILITIES
III. PROFILE ON “VSP”
 VARIOUS DEPARTMENTS IN BRIEF
IV. COKE OVENS AND COAL CHEMICAL PLANT
 COAL AND ITS ORIGIN, TYPES, PROPERTIES
 NEED FOR MANUFACTUREOF COAL FROM COKE
 COAL CHEMICAL PLANT
V. IMPROVEMENTS IN CO & CCD SINCE INCEPTION
VI. BENZOL PLANT
 BENZOL DISTILLATION PLANT
 HYDRO-REFINING UNIT
 EXTRACTIVE DISTILLATION UNIT
 CRUDE AND FINISHED PRODUCTSTORAGEUNIT
VII. QUALITY PRODUCTS COMPOSITION
VIII. USES OF BY-PRODUCTS
IX. UTILITIES
X. CENTRAL LAB
 DETERMINATION OF FOLLOWING COMPONENTS:
 FREE AMMONIA
 TOTAL AMMONIA(KJELDAL’S METHOD)
 VOLATILEPHENOLS
 CHEMICAL OXYGEN DEMAND
 BOILOGICAL OXYGEN DEMAND
 MIXED LIQUOR SUSPENDED PARTICLES

6. INTRODUCTION
The role of ferrous metals in general and of steel in particular in national
economy is enormous. One cannot name an economic branch where ferrous
metals find no applications. The economic power of country is determined by its
output of steel, since it determines the progress in the principle economic
branches, be it mining, transport, manufacture engineering or agriculture
implementsisunthinkablewithoutsteel.
An additional impetus for increasing the scope of steel manufacturers had
been the vigorous progress in chemical engineering. It has turned out that steel
can be very profitable combined with certain novel materials for instance plastic
combined with stainless steel are excellent materials fore making furniture,
decorating automobiles internal lining of houses and building purposes. As a
result the manufacture of stainless steel has been appreciably increased in order
to cover these new demands in recent years. The world for the steel rises
continuously and is expected to reach the level of thousand million tons per year
by the end of this century. The steel will obviously remains the principle structural
materialin for seeable.
To meet the above requirements the following iron and steel companies
were established:
 Tata iron and steel company is the first ever-integrated steel plant in
India in 1908 atJamshedpur.
 TISCO in Bihar
 IISCO in Burnapur
 Bhadravathi steel in Karnataka
 Hindustansteel plantatBhilai,Rourkela andDurgapur
 Visakhapatnamsteel plantatVisakhapatnam

7. VISAKHAPATNAM STEEL PLANT
In order to increase the steel production reasonably high in the nation and
remove the regional imbalances in industrial developments, the government of
India took a great step in setting up the coastal-based steel plant of India is
Visakhapatnam steel plant in Andhra Pradesh. This plant is located 16km south
west of the city limits. A great emphasis has been made on total automation,
seamless integration and efficient up gradiation at Visakhapatnam steel plant.
This has resulted in a great demand for Visakhapatnam steel plant product in
India and abroad which are having international standards. Visakhapatnam steel
plant is considered to be the first integrated steel plant in India to become fully
ISO-9002 certified company. This certificate covers quality systems of training
and marketing functions over four regional marketing functions and 22 stock
yards located all over the country. The decision of the government of India to set
up an integrated steel plant at Visakhapatnam was announced by the Prime
Minister Smt.Indira Gandhi. The plant was inaugurated formally on 20th January
1971 bythe primeminister.
The project was estimated to the cost of rupees 3,897.28 crores based on
process on 4th quarter of 1981 but during the implementation of VSP is has been
on served that the project cost as increased substantially over the sanctioned coast
mainly due to this and the approved concept were studied in 1986 the
rationalization has basically been from the point of view of obtaining maximum
output from the equipment already installed panelled for procurement, achieving
the higher level of operation efficiency and procurement over what was envisaged
earlier under the rationalized concept. 3.0 million tons of liquid steel is to be
produced in a year and the project is estimated to cost 5,822 crores based on 4th
quarter of 1987.

8. VSP’S FRUITFUL ACHIVEMENTS
 It has crossed many milestones in the fields of production, productivity and
exports.
 Coke rate at an order of 543kg/ton hot metal
 Averageconverter life of 649 heats.
 An averageof 11.5 heats per sequence in continuousbloom caster.
 Specificenergy consumption of 7.51 Kcal/ton of liquidsteel.
 Specificrefractory consumption of 15.2kg.
 A labourproductivityof 192-ton/manyr.

9. MODERN TECHNOLOGY & MAJOR
PLANT FACILITIES
THE MODERN TECHNOLOGY
Visakhapatnam steel plant is the most sophisticated and modern integrated
steel plant in the country. Modern technology has been adopted in many areas of
production, someof them for the first timein the country.
Among these are:
 Selectivecrushing of coal
 Dry quenching of coke
 On ground blending of sinter base mix
 Conveyor charging and bell less top blastfurnace
 Cast house slag granulationfor blastfurnace
 100% continuouscasting of liquid steel
 Gas expansion turbine for power generation utilization blast furnace top
gas pressure
 Computerization for process control
THE MAJOR PLANT FACILITIES
 Coke oven batteries of 67 ovens each having 41.6cu.m volumes.
 Sintermachinesof 312 m2 area.
 Blastfurnace of 3200m3 useful volume.
 Steel melt shop with three L.D converters of 150 ton capacity each and 6
nos. of 4 strand continuousbloom casters
 Lightand medium merchantmillof 710,000tonnesper year capacity
 Wire rod millof 850,000tons per year capacity
 Medium merchantand structural mill of 850,000tons per year capacity

10. Extensive facilities have been provided for repair and maintenance as well as
manufacture of spare parts. A power plant, oxygen plant, compressed air plant
also form part of the plant facilities. The steel plant is getting its supply of iron
ore-lumpsand finesfrom the Bailadilla depositsin Madhya Pradesh.
Blast furnace grade limestone comes from jaggayyapeta in Andhra
Pradesh, SMS grade limestone from Jaisalmer and Goton in Rajasthan. Blast
furnace and SMS grade dolomite from Birmitrapur (Orrisa) the Khammam
deposits in Andhra Pradesh. 70% of the coking coal requirements are met by
imports through the harbor while the balance come from the Bengal Bihar area.
Coal for Power generation comes from Anantha deposits of Talcher region in
Orissa.
The plant has in-plant power generation from a power plant having 3 nos.
of 60MW sets installed. Additional requirements of operational power, around
150MVA is being met from the APSEB grid. Operational power supply is initially
at 220 KV, which is subsequentlystepped down to 400 KV.

11. PROFILE ON “VSP”
MAJOR DEPARTMENTS IN VSP
1. Raw materialshandling plant
2. Coke ovens and coal chemical division
3. Sinterplant
4. Blastfurnaces
5. Steel meltshop
6. Rollingmills
a. LMMM (Lightand medium merchantmill)
b. WRM (Wire rod mill)
c. MMSM (Medium merchantand structure mill)
VARIOUS DEPARTMENTS IN BRIEF
1. Raw material handling plant:
VSP annually requires quality raw materials like iron ore, fluxes
(dolomite, limestone) coking coal and non-coking coal. It requires 12-13 million
tonnes of raw materials, which produce three million tonnes of liquid steel. It is
provided with unloading, stacking and reclaiming facilities, which include wagon
, tippler, ground and track hoppers. The variousfeatures are:
 Peripheral unloading system for railwaywagons
 Blenderreclaimed for blendingof ores and fluxes
 Storage yards to facilitate comfortable storage and supply of raw
materials
 Ring granulatorsfor crushing of boilercoals
 PLC control of all systems
 Mixerfor mixing limeispurchased and generated fines
 Cone crushers for the crushing of lumpore.

12. 2. Coke ovens and coal chemical division:
Coke is manufactured by heating of crushed coking coal in absence of air at
a temperature of 1000c and for about 16-18 hrs. a coke oven comprises of two
hallow chambers namely coal chamber and heating chamber. In heating chamber
a gaseous fuel such as gas, coke oven gas is burnt. The heat so generated is
conducted through the common wall to heat & carbonize the coking coal placed
in the adjacentcoal chamber. Variousfeatures of coke oven are:
 7 mts tall coke oven batteries.
 Coke dry cooling or quenching usingNitrogen.
 Recovery of BY-Productfrom coke oven gas by Distillationprocess.
 Twin fuel gas regenerative system for power generation from coke
oven gas.
 Back pressure turbine station for power generation from coke oven
gas.
 Selectivecoal crushing.
 Highproductivity.
 Highcapacityof coke ovens.
1. SINTER PLANT:
Sinter is hard, porous ferrous material obtained by agglomeration of iron
fines, coke breeze, lime stone fines, metallurgical waste like dust, mill scale, LD
slag. Usage of sinter in B.F increase productivity by decrease in the coke rate and
imposing the qualityof hot metal produced. Parametersof the machinesare:
 Effective area 312 m2
 Sintering area 276 m2
 Capacity 450 m2
 Sinterbed height 300mm

13. 2. BLAST FURNACE:
Hot metal is produced in blast furnace, which are tall and vertical. Raw
materials are Iron Ore, Coke, Dolomite, and Limestone. It is charged from the top
and hot blast at 1100c-1300c. there are two B.F’s each with a volume of
3200m3, each with 4 tap holes and with a daily production of 9720 tons of liquid
steel. The technical parametersare:
 Effective volume 3200m3
 Capacity 4860TPD
 Height 33.1m
 Numberof tap holes 4
Each furnace is facilitated with two Cast Houses, Slag Granulation Plants.
There are 4 Pig Casting Machinesto handlethe pig iron to cast into PIGS.
3. STEEL MELT SHOP:
Steel is an alloy of iron with carbon up to 18%. Hot metal produced in
B.Fcontains impurities such as carbon (3.5-4.25%), silicon (0.4-0.5%,
manganese (0.3-0.4%), sulphur(0.04%max) and phosphorous(0.14%max). to
improve the quality of steel, the impurities have to be removed by oxidation
process which is done in converter shop having 3 LD converters. Operational
parametersare:
 Useful volume 133m3
 Capacity 150 tons
 TemporaryLining Tarred Dolomite
 Permanentlining Chrome magnesite
 Oxygen workingpressure 16kg/cm2
4. ROLLING MILLS:
Blooms produced in SMS-CCD do not have much application as they are.
So they are shaped into Billets, Rounds, Squares, Angles, Channels, Wire
Rods, Rein Forced Bars etc. by rolling them in 3 sophisticated high capacity,
high speed, fullyautomated rollingmillsnamelyLMMM, WRM, MMSM.

14. A) LIGHT AND MEDIUM MERCHANT MILL:
It is unique rolling mill; it consists of Billet Mill and Bar Mill. It is
facilitated with 2 walking beam furnaces of 200 TPH heating capacity and 2 stand
roller hearth furnaces. The roller hearth furnace connects the billetwithbarmill.
B) WIRE ROD MILL:
It is a 4-stand mill and is fully automated. The mill has 4 zone combination
type pre heating furnace of 2100 TPH capacity. The mill products include rounds
and ribbed wire in size of 5.5mm-12.7mm dia. Wire rods are made in coil from
having maximum weight of 1200kg. The mill is equipped with retarded still more
linesfor improvingthe qualityof wirerods.
C) MEDIUM MERCHANT & STRUCTURE MILL:
This mill is installed at ground level and has the capacity of roll 8,50,000
ton of medium merchant products per annum. The feed materials to mill are
250mm x 250mm blooms. MMSM is a high capacity continuous rolling mill
consists of 20 stands arranged in 3 train i.e. roughing, intermediate and finishing
trains.

15. COKE OVENS & COAL CHEMICAL
PLANT
ORIGIN OF COAL
Coal originated from the arrested decay of the remains of trees, bushes,
mosses, vines and other forms of plant life, which flourished in huge swamps and
bogs millions of years ago, during prolonged periods of humid, tropical climate
and abundant rainfall. Streams into the swamps and lake basins to form the coal
beds carried an enormous amount of vegetations. Owing to pressure, the streams
have generally been crushed to an elliptical section and formed coal.
USE OF COAL IN VSP
Coal is used in the form of coke to serve the purpose of iron ore reduction in
blast furnace. It also serves as a heat source.
TYPES OF COAL
There are 2 types of coal:
(1) Coking Coal. (2) Non-Coking Coal.
The different coking coals used in VSP are:
1) M.C.C - Mediumcoking coal - BENGAL, BIHAR
2) I.C.C - Imported coking coal - AUSTRALIA
3) I.S.S.A.C - Imported coking coal - AUSTRALIA

16. 4) SOFT - Imported coking coal - AUSTRALIA
In VSP coking coal is used for producing metallurgical coke where as non-coking
coal is used for producing thermal power (in boilers).
TYPES OF COAL AND PROPERTIES
S.NO. TYPE OF COAL % MOISTURE % ASH MEAN
MAXIMUM
REFLUTANCE
1. M.C.C 25-28 17-22 0.9
2. I.C.C 24-26 8-10 1.10-1.3
3. I.S.S.A.C 23-25 8-10 1.16-1.3
4. SOFT 30-34 8-10 0.9-1.0
COKE
It is a strong porous hard mass that is obtained by heating of the coal
in the absence of air at high temperature. It is a reactive fuel and satisfies the
need for blast furnace.
FUNCTIONS OF COKE
1. It actsas heat producer in blast furnace
2. It acts as reducing agent by carbon reduction in blast furnace with oxygen
reaction.

17. 3. It gives a permeablebed and also as a slag carrier.
CARBONIZATION OF COAL
Heating of coal in the absence of air at high temperatures to produce
residue coke, coke oven gas is called “CARBONISATION OF COAL” or
“DESTRUCTIVE DISTILLATION”. Its main purpose is to produce coke and the by-
product known as coke oven gas from which various products are obtained and
thisis used as fuel of high calorific value.
NEED FOR MANUFACTUREOF COKE FROM COAL
1. Natural coal is too dense and fragileto be used as a fuel in the furnace.
2. Coal is not strong enough to withstand nearly 25 mts of burden lying on it
inside thefurnace.
3. Coal is nearly “VOLATILE MATTER FREE” so it does not create problems of
hot shortness and coal shortness.
4. As compared to coal coke is of high quality and is highly reactive.
5. Coke is highly porous mass and it equalizes the blast coming from the
bottomof thecharge.
6. As coke is a rigid hard mass it does not create the problems of dust
nuscence.
7. The ASH CONTENT in coke is very low i.e.) around 10%. So it does not arise
problemsof striking on the grates.
The coke oven and coal chemical plant is mainly divided into the following
department:
1. Coal Preparation Plant (C.P.P)
2. Coke Oven Batteries
3. Coke Dry Cooling Plant (C.D.C.P)
4. Coke Sorting Plant (C.S.P)
5. Coal Chemical Plant (C.C.P)

18. IMPROVEMENTS IN CO&CCD SINCE
INCEPTION
COAL PREPARATION PLANT:
1. Polymer lining done for 14 silos and chutes to prevent jamming/sticking of
coal.
2. Coal receiving conveyors to mixing bins speed increased to avoid stoppage of
conveyoron overload etc.
3. Additional small conveyors installed to blend pitch and sludge to feeding coal
track to coaltowers.
4. Y5 & Y5a conveyors drive drums changed with higher diameter to avoid off-
centering and stoppage on load (jamming).
5. Y5, Y51, Y16 and Y16 return idlers modified to avoid jamming and off-
centering.
6. ConveyorY12 gearbox internal were changedto stop belt reversal.
7. All inclined conveyors were provided with back skirt to avoid spillage.
8. All chutes were narrowed to avoid spillage & off- centering.
BATTERY:
1. Lid catcher flange bolts provided and mounting structures modified in
Charging Cars to avoid off- centering.
2. Pusher Cars and Charging Cars provided with BCH brakes to avoid sliding
of Cars.

19. 3. In all DEs’ door extractor and guide coupling replaced with tie rod and
spring assemblyto avoid detachment.
4. Pusher Car 4,5 leveler bar plat form extended to facilitate door/window
regulation.
5. EB1, 4, 5 & 7 brick and dust collecting bunkers provided.
6. Catenarysystem installed for Charging Cars in all Batteries.
7. DETLsupport brackets provided for all anchor columns.
8. Cable reeling drums installed in DEs’ to continue DETL, GCM work
without stopping production.
COKE DRY COOLING PLANT:
1. Operators cabin shifted out of lifter for safetyand better visibility.
2. Falls post erected in all charging devices to eliminate lowering of hot bucket
if lid is not opened properly.
3. Bucket liner plates design changed to eliminate plates falling from bucket to
to chamber and also to increase the life of liners.
4. Rotary discharging device installedinChamber-12.
5. CDCP 1&2 discharging devices controls changedto PLC.
6. Introduction of Lifter ground control operation while closing and opening of
hooks to avoid single side gripping.
7. Monitoring of all HT drives running horns.
8. Pre-chambermodification to reduce charging device damage.
9. 5 Chambers complete refractorylining changed.
COKE SORTING PLANT:

20. 1. Delayed stopping of K1, K2, K3, K4, K25 & K26 conveyors for emptying the
coke from belt in case of track stoppage.
2. Usage ofBF bunker for storing of nut coke by modifying K21receiving chute.
3. Transportation of Nut coke to BF by modifying P3-1 receiving chute from
K22.
4. Introduction of level sensors in all sludge pump houses for monitoring
overflows.
5. Vibrating screen modification for increasing mesh life and reducing slipping
of belts.
6. Installation of high capacity pumps for 100% recycling of service water in
CSP.
BENZOL PLANT:
1. Up gradationof HRED instrument controlto PLC.
2. Reactorcatalystregeneration.
3. CB1 & CB2 columns taken into line to improve quality of Crude
Benzol.
4. New products HC Benzol, Still bottoms, Polymers were introduced
and sales ofHCB started from Jan’04.
5. 100%recycling of distillation effluents in Benzol unit to MBC.
6. Catchpit introduced in Benzol DistillationUnit for removal of Traces
of oil.
7. In CFPS unit two CB tanks roof replaced.
8. Wall constructed along the boundary of Benzol plant HRED, CFPS
unit and entire area inside boundary wall PCC flooring done.
9. Expansion of Fire Fighting Pump House of BRP.
10. Benzol distillation unit muck is being recycled.

21. COAL CHEMICAL PLANT
Many by products are extracted from the coke oven gas at this
department. It consists of the followingsections:
1. Exhauster house.
2. Ammonium sulphate plant.
3. M.B.C plant.
4. Tar distillation plant.
5. P.C.L.A
6. Naphthalenefraction crystallization.
7. Benzol plant.
 Benzol distillation plant.
 Hydro refining.
 Extractive distillation.

22. BENZOL RECOVERY
PLANT
(PROCESS DESCRIPTION)

23. BENZOL PLANT
Benzol plant is provided in order to produce pure benzene,
toluene, and solvent naphtha. Benzolplant consists of three sections:
 Benzoldistillation plant.
 Hydro refining unit.
 Extractive distillation unit.
 Crude & Finished Products Storage.
Crude benzol recovered from the coke gas is fed to the benzol distillation plant.
Various chemicals in the benzol are recovered by distillation.
OBJECTIVE (BENZOLPLANT):
• To recoverCrude Benzolfrom BenzolisedOil.
• To produce Pure Products from Crude Benzol
In the benzol distillation plant, the Benzolised oil from final
absorption is pumped to the storage tanks of the benzol distillation. The BO is
then stripped of with steam to get the crude benzol and debenzolised oil. This
DBO is again pumped to the benzol recovery section. Makeup solar oil is added
continuously to compensate for the losses in the equipment. The Benzolised oil
is initially pre-heated in three pre-heaters, which are shell and tube heat
exchangers. Pre heating is first done in oil dephelegmators, then oil-oil heat
exchanger and finally in steam pre heaters. The temperature is slowly in order
to prevent chemical decomposition of benzolised oil. The temperature of the
BO fed to the stripping column is about 130-135˚c.

24. The Recovery& Distillation unit has two streams eachconsisting of one final
gas coolertwo scrubbers connectedin series. In scrubber the SolarOil and
CO-Gas is subjected to counter current flow and thus SolarOil absorbs and
Benzol from CO-Gas and becomes Benzolised oil. This Benzolisedoil is taken
to a stripping column, where with the help of direct steam, the benzol is
stripped, removed and cooled. The de-Benzolisedoil is the bottom product,
which is reusedfor scrubbing the CO Gas.
Tube side Shell side
Oil dephlegmator vapours of stripping column BO
Oil-oil exchangers DBO from stripping column BO
Steampre-heaters medium pressure steam BO
SALEABLE CHEMICALS:
• Ammonium Sulphate (PUSHKALA)
• Crude CoalTar
• Hard Pitch
• HP Naphthalene
• Drained Naphthalene Oil (DNO)
• Phenol Fraction
• CG Benzene
• NG Toluene
• Light Solvent Naphtha
• SOL 110
• CoalTar WashOil
• Anthracite Oil

25. • CoalTar Fuel / PCM
EQUIPMENT:
• Two streams.
• EachStream consisting of
- Stripping column -1No.
- Steampre-heater -2Nos.
-DBO Coolers -6Nos.
-Oil Heat Exchangers -3Nos.
- Oil Dephelegmators -2Nos.
- WaterDephelegmators-1No.
- Decanter -1No.
• Common for both streams-
-CB-1 Condensers -2Nos
-CB-1 Column -1No.
-CB-2 Column -1No.
OBJECTIVE (BENZOL DISTILLATION SECTION:
• To separate Crude Benzol from BenzolisedOil.
• To separate HCB from Crude Benzol.

26. OVER ALL PROCESS OF BENZOL DISTILLATION:
Benzol distillation plant receives Benzolised oil from benzol recovery
plant and the Benzolisedoil is treatedto produce crude Benzol.
Benzol distillation plant comprises of Benzolised oil stripping and
fractionationof crude benzol as CB-I, and heavy crudebenzol as CB-II.
The Benzolised oil received from Benzol recovery plant is heated to 118-125
degrees and CB is stripped from Benzolised oil by steam in Stripping Column
and crude Benzol vapour is produced. The vapours are passed through Oil &
Water Dephlegmators for separating phlegma condensate. Then Crude Benzol
vapours are fed into a fractionating column to produce Crude Benzol-I and
Heavy Crude Benzol CB-II.
The stripped oil is called De-benzodised oil. De-benzodised oil is cooled
and sent to Decanter where the oil is separated from emulsion. Then De-
benzodised oil is pumped to Benzolrecoveryplant.
Emulsion from decanter is periodically transferred to emulsion breaker for the
separation of oil and muck by heating. Muck is semi solid mass, generating
during the circulating of oil in process of Benzol recovery due to absorption of
tar fog. Muck is transferred to muck beds for disposal.
The regeneration of oil is done by feeding a small portion of hot
Benzodised oil to regenerator. The bottom from the regenerator containing
polymers called high boiling fraction is collectedin high boiling fraction tank.

27. Steam condensate generated of direct stream stripping is separated in
Phlegm separator, CB-II control separator and collected in a settling tank and
then directed to separated water tank. Water from separated water tank is
pumped to final gas cooling condensed water circuits. Water used in the
decanters for the separation of sludge and other contaminated water is pumped
to final gas cooling condensedwatercircuit.
Crude Benzol is present in range of 25-40g per Nm3i n coke oven gas & it
yields on recovery varied from 6-11L petrol of coal carbonized. The unrefined
product is chiefly a complex mixture of hydrocarbons. But sulphur, Oxygen &
nitrogen compounds are also presentin trace amounts.
At VSP solar oil, a petroleum fraction boiling from 270-370 degree is
used for scrubbing coke oven gas. In Benzol scrubber to recover crude Benzol,
coke oven gas consists of 27-34 g of Benzol hydrocarbons per Nm3/gas. In a
continuous process the benzolised oil thus generated is stripped in Benzol from
the solar oil. & The DBO (debenzolised oil) is sent back to Benzol scrubber for
subsequent absorption.
STRIPPING COLUMN:
Pre-heated BO from the exchangers is fed to the 17th
tray of the
stripping column. The column consists of bubble cap trays. Low pressure of
steam at a temperature of 180°c and 3.8kg/cm2
is injected through DBO at the
bottom of the column.
Crude Benzol in the BO is recovered by steam distillation. Steam
distillation is done so that the partial pressure of the Benzol decreases and
easily get vaporized. LP steam injected at the bottom not only maintains
temperature of the column but also decrease the partial pressure of the crude
Benzol. The crude Benzol vapours along with steam from the top of the column

28. are fed to the oil dephlegrmators. The DBO from the bottom in which crude
Benzol is recoveredis pumped to the decanterthrough oil-oil heat exchangers.
The crude Benzol vapours are partially condensed in the oil
dephlegrmators. The partial condensation removes any higher fractions
present in the vapours which further increases the purity of the vapours. Three
sets of dephlegrmators are provided, two sets for oil and one for water. The
vapours are cooled to 92-95°c in oil dephlegmator by pre-heating the feed to
the stripping column and further cooled to 84 °c in water dephlegmator. The
condensate collected in the heat exchanger is called PHLEGMA. The phlegm
from the exchangers, which contains water, is collected in a separator. Water is
separated and phlegma over flows to the phlegma collecting tank from this
tank phlegma is sent to stripping column as reflux.
REGENERATOR:
The continuous circulation of DBO forms some polymer due to
heating and cooling. This polymer must be removed from the DBO by
regeneration. Regeneration is a hollow tank in which steam coils are arranged
MP steam is circulated through these coils. Part of the stripping column is fed
to the regenerator. Due to the pressure CB vapors are collected at the top,
which are in turn to the stripping column. The bottom liquid from the
regeneratoris pumped out and storedin Crude and Finished Product Storage.
Top temperature 110-115°c
Bottom temperature 120-130°c
No. of trays 23
Feedtray 17 th
tray
Pressure in the column 0.3-0.35

29. CRUDE BENZOL COLUMN I:
The vapors containing crude benzol from the top of the stripping
column is fed to the crude benzol column I through water dephlegmator where
the crude benzol is separated to heavy crude benzol and light crude benzol.
Crude benzol mainly consists of LCB, HCB and polymer. Lighter fractions like
benzene, toluene, and xylene are present in LCB and HCB is similar to that of
heavy polymer, which is used as furnace oil.
The column consists of 16 bubble cap trays. Simple distillation is
carried out in this column. A reboiler provided at the bottom of the column
supplies the necessaryheat. MP steam is used as heating media.
A CB vapour at a temperature of 80-85°c is fed to the 6 th
tray of the
column. The lighter components are vaporized and these are collected at top of
the column, which are then condensed in a condenser by water. The condensed
vapours are then fed to the separator where the moisture present in the
vapours is separated and the LCB obtained is stored in CB1 tanks. Part of the
LCB is fed as reflux to the CB1 column. The bottom product obtained from
CB1 column is fed to the CB II.
Top temperature 70-80°c
Bottom temperature 115-120°c

30. CRUDE BENZOL COLUMN II:
CB II consists of 6 bubble cap trays. The bottom product of the CB I
which mainly contains HCB with small amount of LCB is fed to the CB II
column. To recover the LCB the liquid is to be distilled. The LCB vapours
obtained from the top of CB II is fed to the CB I column as reflux. The bottom
product obtained from the CB II is calledas Heavy Crude Benzol (HCB).
Top temperature 120°C
Bottom temperature 140°C
DEBENZOLISED OIL:
The DBO from the bottom of the stripping column is pumped
through oil-oil heat exchanger to DBO cooler. In DBO cooler it is cooled to 45-
50°C. Due to high temperature exposure, part of the solar oil may get
decomposed. This decreases the absorption efficiency of the solar oil. To
remove this decomposedmatterDBO is fed to the decanter.
DECANTER:
It is a horizontal cylindrical tank unlike mechanical decanters DBO is
fed to the decanter at a temperature of 45-50°C. Small amount of water is fed
to the decanter which provides better removal of sludge or muck form of oil.
Water settles at the bottom carrying sludge with it. Muck or sludge layer is
formed the water layer. Oil layer is formed above the muck layer. The
residence time in the decanter is three to four hours. Water is continuously
drained from the decanter. Oil after 3-4 hours is fed to the DBO tank. Muck
from the decanter is drained and sent to the emulsion beaker. Due to contact of
oil, water and muck oil-water emulsions and muck-water emulsions are
formed. These emulsions float on the surface of the water, which is fed to the
emulsion beakeralong with muck.

31. EMULSION BEAKER:
This is a horizontal cylindrical vessel provided with insulation.
Medium pressure steam is fed through a coil into the beaker. Residence time
for setting the oil, muck and water in the beaker is 2 hours. Due to heating of
emulsion, oil and water get separated which is called as De-emulsification.
Emulsion thus formed is broken and muck will float on water. This muck is fed
to the muck tank and the water is drained. The temperature inside the beaker
is 80-90°C.

32. HYDRO REFINING
In this unit using hydrogen gas purifies the light crude Benzol.
Hydrogen is recovered from coke oven gas and LCB from Benzol distillation
plant.
OBJECTIVE:
• To remove Sulphur, oxygen and nitrogen from Crude Benzol.
• To produce BTXS Raffinate for processing in Extractive Distillation
Unit.
LCB consists of benzene, toluene, xylene, solvent naphtha, non-aromatics and
residue. Initially, the LCB is purified from sulphur, non-aromatics and other
compounds. This consists the following sections. Theyare,
 De-fronting section
 Reactionsection
 Purification section
DE FRONTING SECTION:
In this section, carbon disulphide is removed from the crude Benzol
and this is called as de-fronted crude Benzol. LCB from the storage tank is
pumped to a surge tank, which is meant for intermediate storage. The LCB
from surge tank is pumped to the distillation column through feed pre-heater.
The feed enters the column at a rate of 3 T/hr and at 70°c. Pressure in the
column will be 0.5 kg/cm2
. Sulphur content in the feed is 2000-1800 ppm. This
is decreasedto about 1200 ppm in the column.

33. Distillation column consists of 30 bubble cap trays of which 17th
tray
is the feed tray. Steam is fed into the reboiler, which heats the bottom product
recycled to the column. The remaining bottom called de-fronted crude Benzol
is fed to the reaction section through feed pre-heater. The sulphur is removed
in the form of CS2. Simple distillation is carried out and due to heating CS2
vapours rise in the top and these are condensed in a water condenser.
Condensed CS2 is collected in CS2 vaporizer. Part of it is fed to the column as
reflux and the other part is stored. The DCB obtained is at 70°c and this is fed
to the intermediate storage.
Feedrate to the column 3T/hr
Pressure in the column 0.5 kg/cm2
Sulphur content in the feed 2000-1800ppm
Sulphur content in DCB 1200 ppm
No. of bubble cap trays 30
Boiling point of CS2 45
Temperature at the top of the column 55-65°c
Column bottom temperature 105°c.
REACTION SECTION:
This section consists of reactors and evaporators. Here the hydro
refining takes place in the reactors provided which removes the oxygen,
nitrogen and sulphur content in DCB.

34. PROCESS:
The de-fronted crude Benzol is pumped to the de-fronted storage
tank (V-401) through a filter. The filter is provided to remove the solid
particles and polymers, which may be present in the crude Benzol. The Benzol
filter is an edge type filter and consists of a slotted tube inside a shell with a
specified filter fineness, which is determined by the slots and scrappers. This is
agitatedby a hard crank.

35. The particles are retained at the edges of the slots and must be scrapped off. If
the pressure difference between the inlet and the outlet streams is too high the
concerned filter must be opened and cleaned. The filtered DCB is stored in the
surge drum (V-401). The drum is set to approximately two bars split range
controlled by feeding N2and venting gases. From surge drum, the DCB is fed to
pre-vaporizer at a pressure of 30 bars using 32 stage centrifugalpumps.
PRE-VAPORIZER:
It is nothing but a vertically mounted shell and tube heat exchanger.
The feed is mixed with a part of cycle gas (containing H2 approximately 15% of
the total gas) before it is fed to the vaporizer. This feed is pre-vaporized to
about 160-165°C by means of the main reactor effluent passing through shell
side. The feed at a temperature of 160-165°C is fed to the third mixing nozzle
of stage evaporator.
This vertical heat exchanger is provided with turbulence promoters
in the tube side to achieve high turbulence so that more heat exchange will
occur and no scale formation is attained. This arrangement is provided as the
feedstock is in partial vapour stage (gas-liquid stage) and so fouling of the tubes
will occur rapidly. This arrangement also provides easy cleaning of tubes by
simply pulling the turbulence promoters.
STAGE EVAPORATOR:
The stage evaporator is a long cylindrical vessel provided with three
stages, which are separated by two plates. Demister pads are provided at the
top of the evaporator. Each stage is provided with a mixing nozzle. Two
reboiler E-402 and E-403 are provided for second and first stage respectively.
A gas pre-heater E-404 is also provided in which the rectangle gas (85% of the

36. total gas) is pre-heated to 210°C by the main reactor effluent. E-402 and E-403
are heated by hot oil through tubes at a temperature of 250°C. Rectangle gas
mixed with feed is passedthrough the shell side.
Down comers are placed so that the liquid in the third stage will enter
the secondand from secondto first. Pressure inside is about 20kg/cmm.
The DCB mixed with 15% of rectangle gas is fed at the third mixing
nozzle of the evaporator. The vapours coming from the second stage and the
feed are mixed thoroughly and fed to the third stage. Lighter vapours are
passed through the demister pads and to the pre-reactor. The liquid containing
lighter and heavier substance is passed
through down comers to the second stage. Here the fed is mixed with the
vapours from first stage in the mixing nozzle II and heated in reboiler E-402.
This is fed to the top of the secondstage.
Similarly liquid from second stage flows to first stage. This liquid is
pre-heated in E-403 and mixed with 85% of the rectangle gas in first mixing
nozzle and again fed to the first stage. The temperature at the bottom of the
evaporator is 210°C. Due to heating of the feed the vapours are sent to the top
and any residue or polymers in the feed are collected at the bottom. Part of the
liquid from the first stage is fed to the residue flash drum (V-406) from where
they are recycled to Benzol distillation plant. The lighter vapours from the
flash drum are fed to the surge drum (V-401) nearly this residue would be 3-
4% if total feed.
The vaporization of feed (DCB) in the evaporator is done by
reduction of partial pressure of DCB, which is manipulated by addition of the
rectangle gas. This results in lower operating temperature even at higher
pressures. Vaporization of feed in heat exchanger should be avoided to reduce
fouling of surfaces.

37. PRE-REACTOR:
The vapours from the top of the evaporator at 180°C are heated in a
heat exchanger E-406 to 190-225°C by passing main reactor effluent through
shell side. The reactor is provided with a bed of catalyst i.e. NICKEL
MOLYBDEBUM. In this pre-reactor such as diolefins, styrene and CS2 are
removed by hydrogenation. Feed enters from the bottom of the reactors
through catalyst bed. Hydrogenation of diolefins, styrene takes place in the
presence ofcatalyst.
The temperature at the inlet of the reactor is 190-225°C and this
depends on the life cycle of the catalyst. Due to the exothermic reaction the
outlet temperatures increases to 200-235°C. Due to continuous operation of the
catalyst bed coke like polymerization products deposit on the catalyst bed
resulting in the lower efficiency. This can be overcome by increasing the inlet
temperature of the reactor. Catalyst activity can be determined by the
temperature difference between inlet and outlet, which should be more than
10°C. Catalyst can be regenerated by heating the bed with steam and air. The
reactions in the pre-reactorare
Diolefins + H2 monoolefins
CnH2n-2 CnH2n
Cyclopentadiene + H2 cyclopentane
C5H6 C5H8
Styrene + H2 ethyl benzene
C8H8 C9H10
Carbon disulphide+ H2 methane+ H2S
CS2 CH4

38. MAIN REACTOR:
In main reactor treated pre-reactor effluent is hydrogenated on
special sulphide molybdenum catalyst. The main reactor consists of two beds of
catalyst makeup gas i.e. pure H2 gas from the compressor at pressure of 18
bars provided more hydrogenation and hence complete saturation of olefin
hydrocarbons. The inlet temperature is about 270°C and the outlet
temperature is 330°C due to exothermic reaction. Mainly desulphurization,
densification and olefin saturation feed stock occurs in main reactor. The
hydrogen is fed through a distributor below first bed of catalyst oxygen content
in H2 gas should be very low so that no polymerization occurs in the reactor.
Hydrogenation of aromatics should be prevented. Catalyst deactivation can be
determined by the amount of thyophene content at the outlet of the reactor. If
this increases hydrogenation of aromatics, coke formation increases. So the
temperature of the reactor should be increased or other regenerations should
be done.
Main reactions are:
Mono olefins + H2 Paraffin
Ethyl mercaptans + H2 Ethane + H2S
Thyopene + H2 Butane + H2S
Coumarone + H2 Ethyl benzene + H2
Pyridine + H2 Pentene + H2
Pyridine + H2 Butane + H2
Benzene + H2 Cyclohexane
Toluene + H2 Methyl cyclo hexane

39. Hence required to maintain a heater to which part of the effluent is
passed, Heated and fed to the main reactor supplies the temperature. Coke
oven gas is used as fuel in the heater.
The effluent from the main reactor collected at the bottom, which is
at 330о
c. This effluent is passed through E-407, E-406, E-404, E-401 and finally
cooledin watercoolerE-408.
This condenser effluent is fed to the separator. Before water cooler hot water is
dosed into the effluent. This dissolves the deposits of salts such as NH4HS2 and
NH4Cl. The cooled effluent at 50 о
c is fed to the separator. A water leg provided
separates the dosed water. The water free effluent is fed to the stripping
column. The gases i.e. un reacted hydrogen gas and other gasses are sucked by
recycle gas compressor and are recycled part of the gas is purged out through
vent provided.
HOT OIL SYSTEM:
The heat demand of the process is supplied by a separate hot oil
system. The hot oil is used as a heating medium for several heat exchangers in
hydro refining unit and extractive distillation unit. A horizontal furnace is used
to heat the oil; the furnace is fired using coke oven gas. Hot oil is pumped in to
the coils into the furnace. The temperature of the oil increases to about 340-350
о
c. The hot oil is pumped by P-404 pump. The oil at temperature of 340 о
c is fed
to the HR unit by using another pump. This is again recycled to the suction side
of P-404.

40. PRESSURE SWING ADSORPTION UNIT:
The required hydrogen gas to HR units is supplied from this section.
The clean coke oven gas after Benzol recovery is fed to a filter at a pressure of
800mm WC. Moisture and carbon particles present in the gas are filtered and
the filtered coke oven gas is fed to a reciprocating compressor, which
compresses the gas to about 2.5 kg/cm2
. The compressed gas is again fed to the
other compressor where the pressure of the gas increases to 6.5 kg/cm2
. The gas
is then fed to another filter, which removes the moisture in the gas. From the
filter the gas is fed to the pressure swing adsorption unit. It consists of 4
cylindrical vessels in a bed of molecular sieves is placed. The coke oven gas is
passed from the bottom of the bed and the molecular sieves absorb the
hydrogen present in the gas. The hydrogen thus collected is fed to the makeup
gas compressor. The gas is passed through one catalyst bed only. At this time,
the remaining beds are in regeneration. This is because catalyst for 180 seconds
only. Then it has to be regenerated. This is done by using pure H2 gas. The
regenerationof then bed is done automatically.
The H2 gas is collected from the top of the bed and is fed to the
makeup gas compressor. This is a vertical reciprocating compressor of double
stage. The H2 gas is compressed to about 30 bar. The recycle gas from the gas
separator is fed to the recycle gas compressor, which is a horizontal single stage
compressor.
PURIFICATION:
This section consists of a stripping column in which the sulphur
content as H2S and any dissolvedgases in the DCB are removed.

41. PROCESS:
The liquid part from the separator is fed to the stripping column
through a pre-heater, which is heated by BTX solvent from the stripping
column. The fed at a temperature of 135 о
c is fed to the column. The column
consists of sieve trays. Top temperature is 125-135 о
c and bottom temperature
is 150 о
c. Pressure is about 4.3 kg/cm2
. Re boiler is provided which supplies the
required heat to the column. MP steam is fed to the shell side of the re boiler.
The gas from the column contains H2S. These are condensed in the condenser
where water issued. This condensate (70 о
c) is fed to the reflux drum. Part of
the condensate is refluxed to the column. Moisture present in the gas is
removed from the waterleg and the off gassesare fed to the off gas mains.
The bottom product called BTX solvent raffinate is passed through
the pre heater where it is cooled and finally raffinate is cooled in the raffinate
coolerwhich is cooledby water. This is storedin intermediate storage.

43. EXTRACTIVE DISTILLATION UNIT
In this unit, the BTX raffinate is processed to separate benzene, toluene
and xylene solvent. Further benzene and toluene are also separated. Using
‘Extractive Distillation’ in which N-formylmoropholine (NFM) is used as
solvent does separation of BTX into BT and X. Non aromatic compounds
present in BTX are removed by pressure distillation solvent is recovered in
solvent recovery column. Benzene and toluene are separated in BT separation
column.
The total heat required for the unit is supplied from various means
pressure distillation receives heat from hot oil. Aromatic separation column
and solvent recovery column receives heat from the vapours of the pressure
distillation column. The BT column receives heatfrom the LP steam.
OBJECTIVE:
• To separate non aromatics from benzene & toluene.
• To produce pure benzene, pure toluene, Light solvent oil &still bottom
oil from BTXS Raffinate.
The unit consists of the following sections:
 Pressure distillation section
 Extractive distillation section
 Solvent recoverysection
 Aromatic stripper
 BT separationsection
 BatchDistillation section

44. PRESSURE DISTILLATION SECTION:
This sectionconsists ofa distillation column in which the BT & X solvent
are separatedby simple distillation from raffinate.
PROCESS:
The BTX solvents raffinate from the IPS is pumped to the feed surge
drum (V-513). The drum is a horizontal tank provided with a vane and line
from reflux drum (V-501) that carries vapours to this drum. The BTX solvents
raffinate from the surge drum is pumped to pressure distillation column
through four heat exchangers I series E-502, E-503, E-504 & E-505respectively.
E-502 and E-505 are heated by bottom product i.e. Xs fraction. E-503 and E-
504 are heated by BT fraction. The column consists of 50 bubble cap trays of
which 25th
trays is the feedtray. Column pressure is about 15 kg/cm2
.
A re boiler is provided to the column through which hot oil passes
through shell side. These supplies the heat required for the column. The BT
vapours from the top of the column a collected in reflux drum before which
they are condensed in E-504 and E-509. This condensed BT fraction is collected
in reflux drum. Some of it is reflux to the column and the remaining is passed
to E-503 and cooledin BT condensedin E-501 by using water.

45. EXTRACTIVE DISTILLATION COLUMN (C502):
The BT surplus is conveyed by steam pressure from V-501 via heat
exchangerE-503 and cooler E-501 as feed to extractive distillation column C-
502. The feed is introduced on the 31st tray at the middle of the column. The N-
formylropholine (NFM) solvent is introduced on the top tray of the ED Column
at the physically required conditions at the flow ratio of 56 kg NFM per kg of
feed at 92о
c. The NFM temperature is regulated for the achievement of the low
level of aromatics in the non-aromatics.
ED column serves for the separation of non-aromatics contained in the
feed, which is not possible under normal distillation conditions. This means
that non-aromatics originally with boiling points higher than aromatics,
becomes low boiling non-aromatics which can be withdrawn at the top of the
ED column while the aromatic substances dissolve in the NFM is yielded at the
bottom of the ED column.
ED column is supplied by the reboiler E-507 (LP Steam), E-508 (Hot
NFM) and partially via vapour heated reboiler E-509. The NFM at the top of
the column promotes the scrubbing of aromatics out of ascending vapours;
where as non –aromatic vapours are dissolvedonly to a slight extent.
ED column trays 60-bubble cap
Feedplate 31 tray
Top temperature 110о
c
Bottom temperature 150о
c
Top pressure 0.8kg/cm2
Bottom pressure 0.4kg/cm2

46. SOLVENT RECOVERY COLUMN:
The column is used for separation of non- aromatics yielded at the top of
ED column from the residual carried over solvent contents. For this purpose
the top vapour of the ED column are fed at the point below at the pall rings
packing in the column. Bottom heating to the column is affected using
reboilerE-510, also by means of hot NFM from the solvent circulation. The top
phase in the column, consisting principally of non-aromatics is condensed in
condenser E-511 and the liquid phase yielded is routed to the reflux vessel V-
502. A portion of the non-aromatics is routed as reflux to the column. While
bottom product is dischargedthrough a level controllerto CFPS.
NFM recovered at the bottom of the column is returned to the ED
column. The solvent recovery column minimizes the NFM losses by means of
extensive recalculation of NFM flow inevitably leaving the top of the extraction
column. The basic difference as compared to the normal hydrocarbon
distillation and ED column is that its bottom section must be operated in the
phase occurs in V-509. The bottom contains large quantities of non-aromatics
due to the reflux required for scrubbing. In contrast to an ED column, the
recovery column is operated under normal circumstances with a two-phase
bottom product.
Packing Pall rings
Bottom pressure 0.25 kg/cm2
Top pressure 0.2 kg/cm2
Top temperature 100о
c
Bottom temperature 125о
c

47. STRIPPING COLUMN:
The product yielded at the bottom of the ED column consists of NFM in
which the extracted aromatic substances are dissolved. The non-aromatic
content will be in low PPM due to the existing pressure drop. This flow is
conveyed into the aromatics column, which is operated under vacuum. In this
column the pure aromatics are separated from the NFM, which is yielded as
the bottom product and cooled in the heat exchanger system of the equipment
prior to be being returned to the ED column.
Before feeding NFM to the ED column, it is passed through the following
equipment:
1. Centre re boiler E-508 on ED column C-502.
2. Re boiler E-512 on solvent recoverycolumn.
3. NFM re boiler E-514 on the stripper column
and then fed to the ED column.
Solvent cooler E-522 serves as a trim cooler for NFM. The bottom of the
stripper column is heated by means of the two continuous re boilers E-512 and
E-513, whichare heated by BT vapours and E-514 heatedby means of NFM.
The reflux to the stripping column serves to remove the solvent in the
lower section of the column. The vapour liquid mixture discharges from the re
boiler E-514 is fed below the chimney tray in the stripping column. Traces of
the solvent flash are washed back by the aromatics reflux and directed into the
lowerpart of the column.
Totaltrays 30
Feedtray 5 th
Top temperature 56о
c
Bottom temperature 119о
c
Pressure 0.36-kg/cm3
vacuums

48. BENZENE TOLUENE SEPERATION COLUMN:
BT separator is a normal two-phase distillation for pure aromatics. The
BT fraction is routed using a reflux pump from reflux drum via exchanger E-
517 to separation column C-505. The heat required for distillation is supplied
to the system via re boilers E-518 by means of LP steam. Overheads are pure
benzene, bottom are pure toluene as specified.
Totaltrays 65 Bubble cap
Feedtray 30 th
Pressure 1.2 bars
Benzene purity 99.97%
Toluene purity 99.95%

49. CRUDE &FINISHED PRODUCT
STORAGE UNIT
OBJECTIVES:
• To store crude Benzol, HCB and pure products.
• To DespatchHCB and pure products to customers by road tankers.
EQUIPMENT:
Total Storage capacity
• CB Tanks 4Nos 2800kl.
• PB Tanks 4Nos 2000kl.
• PT Tanks 2Nos 400kl.
• LSO Tanks 5 Nos 250kl.
• NA Tanks 2Nos 100kl.
• HCB Tanks 2Nos 200kl.

50. QUALITY PRODUCTS (Composition)
TOLUENE (Industrial Grade)
 Distillation Range
Up to 1050
C 5 ml
Up to 1200
C 90 ml
• Specific Gravity at 15/150
C 0.860 - 0.875
• Residue on Evaporation 10 mg/100 ml (max)
• H2S & Mercaptanes Negative
• Purity (by GLC method) 92.0 % (min)
TOLUENE (Nitration Grade)
• Distillation Range 0.6 (Including 110.60
C)(1 -96%)
• Specific Gravity at 15/150
C 0.870 -0.874
• Residue on Evaporation 5 mg/100 ml (max)
• H2S & Mercaptanes Negative
• Purity (by GLC method) 99.2 % (min)
CG BENZENE
• Distillation Range 0.6 (Including 80.10
C)(1 - 96%)
• Specific Gravity at 0.879 - 0.886
• Residue on Evaporation 5 mg/100 ml (max)
• H2S & Mercaptanes Negative
• TotalSulphur (ppm max.) 2.0
• Non Aromatics (ppm max) 500

51. USES OF BY-PRODUCTS
TOLUENE
• Solvents, TNT, Paint ,Rubber Industries, & Varnishes
• Printing Ink, Benzoic Acid, Sodium Benzoates
• Synthetic Fibers, Adhesives, Benzyl Chloride, Thinners
HP NAPHTHALENE
• Dye intermediates, Insecticides
• Dispersing & Tanning Agents
• Beta Naphthol, Refined Naphthalene
• Naphthalene balls
BENZENE
• Raw material for various Drugs, Dye-stuff, Synthetic Rubber, Styrene.
• Pesticides,Monochlorobenzene
• Caprolactum, Phenol, DDT
• LAB Nitro Benzene, Aniline, Maletic Anhydride
• Cumene, Cyclo-Hexane
• Nylon-6, Styrene
• Resin, Nylon Intermediates

52. HARD PITCH
 Used by Aluminium Industries requiring Pitch Carbon for Electrodes.
 Used for manufacturing graphite and in BF ladle repair.
AMMONIUM SULPHATE
 As Fertilizer due to its Nitrogencontent.
 As a Nitrogen bearing material in mixed Fertilizer in Fertilizer
plant.
ANTHRACENE OIL
 Feedstock for Carbon Black.
DRAINED NAPHTHALENE OIL
 Naphthalene balls
 Naphthalene bearing feed stocks
COAL TAR WASH OIL
 Preservationof WoodenSleepers
 Carbon Black FeedStocks, Disinfectant
LIGHT SOLVENT NAPHTHA
 Solvents, Starting material for Dyes, Printing Ink, Thinner

53. UTILITIES
Utilities department supplies other utilities required for various
department such as oxygen, nitrogen, chilled water, compressed air &
instrument air.
DIFFERENT SECTIONS IN UTILITIES:
 Air separationplant.
 Compressorhouse.
 Acetylene plant.
 Chilled waterplant.

54. QUALITY ASSURANCE &
TECHNOLOGY DEVELOPMENT
(CENTRAL LAB)
DETERMINATION OF FREE AMMONIA: (DISTILLATION METHOD)
1) 50 ml of sample is takenintoa kjeldal flask.
2) The sample is arranged into a conical flask containing into a 2% Boric acid
solutioni.e. 50 ml of 2% Boric acid + 50 ml of DM water + mixedindicator.
3) After 30 min
4) Distillation, the set up is removed and the condensate is titrated against
N/10 H2SO4.
CALCULATION: ml of N/10 H2SO4 consumed × 34
DETERMINATION OF TOTAL AMMONIA (OR) AMMONICAL N2 (KJELDAL
METHOD):
1) Take 10 ml of filtrate sample intoa kjeldal flask.
2) Add 10 ml of 6N NaOH and 10 ml of Borate Buffer and 100-150 ml of Dm
water.
3) Take 100 ml of 2% Boric Acid in a beaker, add 2-3 drops of mixed indicator,
and keepthe beaker, belowthe water condenser toabsorbthe ammonia.
4) Arrange the distillation unit and switch on. Boil the contents till the volume
reducedto1/3rd
.

55. 5) Now remove the beaker in which ammonia is absorbed. Titrate it with 1N
OR N/10 H2SO4 colour changes from greentored.
CALCULATION:
Total NH3=(T.V ×Normality ×17×1000 ) /vol.of sample taken
DETERMINATION OF VOLATILE PHENOLS:
PRINCIPLE:
Steam distiable phenolic compounds react with 4-Amino anti pyrine
at Ph 7.9 in the presence of potassium ferric cyanide to form a coloured
Antipyrine dye. This is measuredat 510 nm wave lengthinSpectrophotometer.
PROCEDURE:
1) Take 50(or) 100 ml of sample, add 10 ml of 10% Cuso4 solution to this add
10 ml OF 1:3 H2SO4 and fewdrops of methyl orange indicator.
2) Take themall intoa kjeldal distillationflask.
3) The distillation as to be conducted by using steam. And collect 500 ml of
distillate.
4) From this take 50 ml of distillate and add 1 ml of ammonia buffer, 2 ml of
8% potassium ferric cyanide and 2 ml 2% 4 amino anti pyrine in a 100 ml
volumetric flask.
5) Nowmake up the volume to 100 ml withthe distillatewhat we collected.
6) Keep it for 15 min and measure absorbance at 510 nm wave length. Run
the blank simultaneously.

56. CALCULATION:
Vol. of Distillate collected/vol. of.sample×k×absorbance
K=Calibrationfactor=7.4
DETERMINATION OF CHEMICAL OXYGEN DEMAND:
1) 50 ml of sample is taken into a round mouthed 500 ml conical flask and 50
ml of water is added in it.
2) Then 25 ml of 0.25 N K2Cr2O7 and 75ml of conc.H2SO4 is added and kept for
cooling in the water bath.
3) After cooling, 1 gm of silver sulphate and 1 gm of Mercuric sulphate and
few glass pieces are added tocontrol the bubbling.
4) After all additions the conical flask is placed on a heater for refluxing for 4
hours using condenser. After reflux the flask is cooled and washing of
condenser is Collectedinthe flask.
5) The refluxed sample is titrated against 0.25 N Mohr’s solution (FAS) using
Ferroinindicator.
6) The COD in ppm is calculatedas
Normality of Mohr’s (0.25) × Y× 8000
Amount of sample takenin ml.
Y= ml of 0.25 N K2Cr2O7 added – ml of Mohr’s solution consumed for titration.

57. DETERMINATION OF OILS&GREASES:
1) Take 100 ml of sample is taken ina separating funnel and add 200ml of
Petroleumether is addedas successive separations.
2) Then the funnel containing sample is shaken vigorously for 5 min with
intimately releasing the vapour pressureandallowedfor settling for 15
min.
3) The aqueous layer is drained from bottomof the separating funnel and
petroleumether is transferred tothe tared porcelaindish.
4) The porcelaindishis kept in over the water bath. It is kept always in water
bath. It is kept always in water bath because if you dry it directly onflame
it catches fire.
5) After the evaporationof ether the dishis cooledin a desiccators and
weighed.
The oils & greases is calculatedas:
Final – Initial wt of dish×106
Sample taken
DETERMINATION OF BIOLOGICAL OXYGEN DEMAND (BOD) :
1) Two sets of BOD bottles, eachset containing twobottles labelled as blank
and sample are taken.
2) Twenty ml of sample is pipettedintoBOD bottleslabelledas sample.
3) 10ml of seedpreparedas per work procedure.
4) The BOD bottles are filleduptothe mark withdilutionwithDM water.
5) 10ml sample is taken ina blank BOD bottle.
6) Dissolvedoxygencontent is measuredimmediately for one set of BOD
bottles by Membrane Electrode Method. (Blank &sample)
7) The other set of BOD bottles are incubatedat 200
c for 5 days in BOD
incubator. And the temperature of incubator is monitored frequently.

58. 8) The BOD bottles are takenout from incubationafter 5 days and dissolved
oxygencontent is measuredimmediately by Membrane ElectrodeMethod
for Blank (B2)&sample(S2)
CALCULATION:
BOD= (S1-S2) – (B1-B2) × 15
S1= Initial dissolvedoxygeninthe sample.
S2= Dissolvedoxygenleft out inthe sample after 5 days incubation.
B1= Initial dissolvedoxygeninthe blank.
B2= Dissolvedoxygenleft out inthe sample after 5 days incubation.
DETERMINATION OF MIXED LIQUOR SUSPENDED SOLIDS:
1) 10 to 25 ml of sample is takenin a beaker.
2) The sample is filtered in a free weighed GFC filter paper under suction by
the set up providedfor this purpose
3) The filter paper is removed and dried in a drying oven. Then filter paper
withthe residue is weighed.
4) The MLSS is calculatedinppm as
(X-Y) ×106
Z
X= Final weight of filter paper inmg
Y= Initial weight of filter paper inmg
Z= Volume of sample takenin ml

59. CONCLUSION
The above describes the main features of the majority of coke oven by-
products plants around the world. Coal properties and plant design and
operationinfluence the actual quantities.
Blast Furnaces, the mother units of any Steel plant require huge quantities
of strong, hard and porous solid fuel in the form of hard metallurgical coke for
supplying necessary heat for carrying out the reduction and refining reactions
besides acting as a reducing agent. At VSP there are Four Coke Oven Batteries, 7
Metre tall and having 67 Ovens each. Each oven is having a volume of 41.6 cu.
metre & can hold upto 31.6 Tonnes of dry coal charge. There are 4 Coke Dry
Cooling Plants (CDCP) each having 4 cooling chambers. Nitrogen gas is used as the
Cooling medium. The heat recovery from nitrogen is done by generating steam
and expanding in two back pressure turbinestoproduce 7.5 MWeach.
The Coal chemicals such as Benzole (& its products), Tar (& its products),
Ammonium Sulphate etc. are extracted in Coal Chemical Plant from C.O. Gas.
After recovering the Coal chemicals the gas is used as a by product fuel by mixing
it with gases suchas BF Gas, LD Gas etc. A mechanical,
Biological &chemical treatment plant takes care of the effluents.

60. REFERENCES
1) en.wikipedia.org/
2) Data from the in charge officers
3) VSP website: https://www.vizagsteel.com/index.asp
4) www.google.com