Indian Oil Corporation Limited Winter Vocational Training Report

Submitted by: RAHUL KUMAR

Roll No. 151200034 IIT GUWAHATI

ABSTRACT

This report is prepared at Indian Oil Corporation Ltd. ,Noonmati , Assam as a part of

. the Industrial Training and contains brief description of the refining process employed

. in the IOCL. It mainly focuses on the process description of various Units and respective

. diagram of that units. The details of the each units is briefed as a part of practical training

. along with the methodology and the procedure adopted are also included in this report.

Project Guide ,

Edmund Ekka

Production Unit

PREFACE

Any amount of the theoritical knowledge is incomplete without exposure to industrial practice.

Practical knowledge means visualization and application of knowledge which we read in books.

Theoretical studies can't be perfect without practical training. Hence , in plant training is of great

great importance for an engineering students. Teaching gives theoretical aspect of technology ,

but practical training gives knowledge of industies activities.

My aim for this industrial training was to look over different units incorporated in refining process.

This training reports present a detailed summary of my enriching Industrial experience at Assam refinery.

Marketing R & D Refinery Pipelines

Major Division of IOCL

Indian Oil corporation Limited ( Indian Oil ) owns and operates a network of crude oil and petroleum

product pipeline in india. It has 2 div : Refineries Division and Marketing Division . The refineries Division is

focused on managing the public sector refineries and the Marketing Divison is focused on distribution not

only the entire production of public sector refineries but also the deficit products imported . It is Organised

into 2 segments : sales of petroleum products , and the other busniesses ,which comprises sales of

imported crude oil, sale of gas , petrochemicals , explosive and cryogenics, wind mill power generation and

oil and gas exploration activities jointly undertaken in the form of unincorporated joint ventures .

ACKNOWLEDGEMENT

With completion of this internship report ,I would like to express my .

. gratitude to all the peopl who helped and guided me .

Special Thanks to Edmund Ekka sir for their valuable time and co-operation

. throughout this internship.

I would also like to extend my gratitude to Sarmap mam for giving such

. a nice opportunity to expeirnce Industrial world.

i

INDIAN OIL CORPORATION LIMITED

GUWAHATI REFINERY

Guwahati Refinery of Indian Oil Corporation Limited , the first of its kind in the Country's Public Sector was

set up in collaboration with Romanian Government. It was Originally designed to process 0.75 MMTPA of

indigenous Assam Crude as was commissioned on the 1st jan 1962, the refinery was revamped in 1986 to a

capacity of 1.0 MMTPA , and further in the year 2000 the capacity was further increased to 1.3 MMTPA .

Oil India Limited ( OIL) supplies crude oil to the refinery . There are Guwahati-Siliguri and Guwahati

– Betkuchi product pipelines for dispatch of products from Guwahati to Siliguri and Betkuchi.

Process Unit in Plant

1> Crude Distillation Unit [CDU]

2> Delayed Coking Unit [DCU]

3> Kerosene Treating Unit [KTU]

4> Naphtha Splitter Facilities 1984 [NSF]

5> LPG Recovery Unit 1994

6> ISOSIV Unit 2002

7> INDMAX Unit 2003

8> Hydrogen Unit 2002

9> Diesel Hydrotreating Unit 2002

10> Sulpher Recovery Unit 2003 [SRU]

11> Nitrogen Unit 2002 [NU]

Utilities of Guwahati Refinery

Thermal Power Station [TPS] De-mineralized Water Plant [DM Plant]

Cooling Tower for Water

Nitrogen Plant

Hydrogen Generation Unit

Compressed Air System

Effluent Treatment Plant

FIRE AND SAFETY DEPARTMENT Fire is a chemical reaction in which heat is generated and it is called "Combustion". Fire results from

the combination of fuel combustible materials , heat and oxygen . The Temperature at which fuel catches

fire is called "Ignition temperature " and it depends upon the properties of materials.

COMMON CAUSE OF FIRE IN THE REFINERIES

FIRE PROTECTION IN THE REFINERY

1> Fire Station

2> Foam chamber connection to storage tanks

3> Fire water mains

4> fire monitors

5> Fire water sprinkler system

6> Fire water storage tank

7> Fire Water booster pumps

8> Fire fighting steam points

9> Automatic CO2 installation

SOURCE OF EXAMPLES PREVENTION MEASURES

Electric Equipment

Defect in wiring , switches Use proper capacity equipments

Friction Moving parts n poor adjustment Regular monitoring

Open Flames

Blow lamps , welding torches Precautionary measures must be taken

Auto ignition

Hot vapours / liquid coming in contact with air

Prevent leakage provide steam lancers and insulation

10> Dry riser

11> Fire siren

12> Fire Alarm system

METHODS OF EXTINGIUSHMENT

1>Breaking of the chain Reaction 2> Cooling 3 > Smothering 4> Starvation

DIFFERENT FIRE EXTINGUISHING AGENT

1> Water 7> Blanketing

2> Mechanical Foam

3> Dry chemical powder

4> Carbon Dioxide

5> Steam

6> vaporising Liquid

CRUDE DISTILLATION UNIT [CDU]

The Crude distillation unit is the first major processing units in the refinery. They are used to separate

the crude oils by distillation into fractions according to the boiling point so that each of the processing

units following will have feedstock that meets their particular specifications.

COMPOSITION OF CRUDE OIL

Petroleum or crude oil is a combustible oily liquid of reddish brown or sometimes almost black

produced from oil wells. It is a complex mixture of various hydrocarbons and their derivatives

containing Sulphur , Nitrogen , Oxygen and metals .

MAIN CONSTITUENTS OF PETROLEUM HYDROCARBONS

1> Paraffinic Hydrocarbons (Alkenes)

2> Naphthenic Hydrocarbons (Cyclo-alkenes)

3> Benzene Hydrocarbons (Arenes)

4> Unsaturated Hydrocarbons (olefins)

5> Oxygen containing compounds

6> Sulphur compounds

7> Nitrogen compounds

8> Minerals substances

PROCESS DESCRIPTION

The crude is pumped at about 15.8 Kg/cm2 through a preheat train where it is heated by

prefactionator overhead vapors to a temperature of 130 o C before entering the desalter .

In the desalter , demulsifier mixed crude is mixed with hot water through a mixing valve.

Thus , the salt in crude dissolve in water and separated from the oil. The remaining salted water

droplets in oil are removed in the presence of electric field. The effluent water preheat the

incoming wash water in E101 before being sent to desalter wash water vessel. The desalter

pressure is maintained at about 13.0 to 15.0 Kg/cm2 below the tripping value.

Crude after desalter ( about 130oC) is pumped to Pre-topping Column (CL-1) for pre-fractionated

through the two pre-heat TRAIN "A" and TRAIN"B" . From pre-topping column (IBP 110 OC) , TBP

cut drawn from column top as light gasoline to stabilizer feed surge drum through caustic wash

vessel. And rest topped crude from pre-topping column (CL-1) bottoms is pumped to atmospheric

furnace via a train of exchangers at about 246 OC .The furnace is a vertical cylindrical type has

two passes with bottom firing and has convection and radiant section. The topped crude enters on

flow control to each of the two passes of the furnace. After heating up to 365 OC this partially

vaporized crude from the furnace outlet is routed to the flash zone of the main fractionating

column (CL-2) . In main fractionating column crude is separated into different products of different

cuts. The over heat of the column collected in main fractionating column reflux drum (V-1). The

Hydrocarbons from V-2 are pumped as heavy gasoline to NSF feed surge drum. From column ,

three sides drawn SR Kero-1, SR Kero-2 , SRGO routed to strippers CL-3A, CL-3B and CL-3C

respectively.

After that each product is pumped out from bottom through exchanger and cooler to respective

storage tank at around 40 OC . The bottom portion of CL-2 is pumped out as Reduce Crude oil(RCO)

through exchanger and cooler to storage tank at around 75 OC or it can be directly used as feed of

delayed Coking Unit (DCU) at around 95 OC.

The unstabilized naphtha or light gasoline from stabilizer feed surge drum is routed to stabilizer

through a train of exchanger at around 125 OC for LPG recovery. FRO Stabilizer top finished LPG

is pumped out to the storage vessel. Stabilizer bottom as stabilized naptha mixed with heavy

gasoline coming coming from NSF feed surge drum and routed to spiltter -1 column through a

train of exchangers. From splitter -1 a top cut of 45-130 OC is pumped out to storage tank as

Light Naptha (LN). From bottom of splitter a part routed to furnace that circulated again in

column and rest are pumped out to splitter -2 for further splitting through a chain of exchanger.

In splitter-2 , naphtha is splitted into 2 cuts and from splitter-2 top (100-155 OC ) cut drown as

Reformed Naphtha (RN). From bottom of splitter -2 a part routed to furnace that circulated

again in column and rest are pumped out as Heavy Naphtha (HN) Through exchanger and cooler to

storage tank at around 40 OC .

Feed:-Crude oil

Top Product:-gasoline, kero-I, kero-II, Strainght Run Gas oil

Bottom Product:- Reduced Crude Oil(RCO)

DELAYED COKING UNIT [DCU]

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

finally 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 andcoker 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 495 o C) to

crack the heavier ends for producing the lighter ends. At this temperature the larger hydrocarbon

molecule 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 , Gasolene ,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 .

CHEMICALS IN DCU

1> Ashuralan ESK50 : Used CL-2 overhead condenser . work as corrosion inhibitor.

2> Silicon Fluid : Used in chamber. Work as an antifoaming agent.

3> Caustic Soda : Used in LPG and Gasoline wash to remove sulfur bearing component .

TYPE OF REACTIONS

1> Primary Reaction :

CH3CH2 CH2CH3 = CH4 + CH3CH=CH2

CH3CH2 CH2CH3 = CH3CH3 + CH2=CH2

2>Secondary Reaction :

2CH2CH2 = C4H8

3C 3H 6 = C 9H18

C4H8 + C9H18 = C 13H26

CH 3CH 2CH=C=CH2 = CH3CH 2CH2CH3CH2CH=CH

PROCESS DESCRIPTION

1> Pumping and preheating of RCO feed

2> Introduction of RCO feed to the main Fractionation's (003-CL-02) and control of bottom temp.

3> Introduction of Fractionation's (003-CL-02) bottoms into Heater and cracking.

4> Cracking to coke and distillates.

5> Removal of RFO.

6> Fractionation

7> Withdrawal of side cuts

8> Cooling of CR

9> Coke chamber operations

The fractionator coloumn has 43 trays, the bottom trays are segmental baffles type, trays

numbered 2-17 are of seive type and rest are of valve type.

In the fractionator column, CK 1, CGO and CFO are obtained as products.The coker fractionator

overhead vapours are partially condensed in the Air cooled condenser and are further condensed in

trim condenser.

INDMAX

INDMAX is a high severity catalytic cracking process exclusively developed by Indian Oil

Corporation R &D Center to produce very high yield of LPG from various hydrocarbon

fractions viz , Naphtha to residues. The process employs proprietary catalyst formulations

having excellent metal tolerance with coke and dry gas selectivity. The operating conditions

of the unit are such that the liquid hydrocarbon products are selectively over cracked to LPG

containing fractions of C3 and C4 olefins without proportionate increase in dry gas and coke.

The 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. The process operates at reaction temperature of 530-600 oC , catalyst to oil

ratio in the range of 15-25 (wt/wt) with higher riser steam in the range of 10-15 wt % of feed.

Salient features of INDMAX process is the high selectivity Fluidized Catalytic Cracking (FCC)

process in which high molecular weight components are cracked to LPG range products .

The special features that distinguish INDMAX from FCC are as follows :

High yield of LPG (40-65 Wt% of feed )

High propylene (17-45 Wt % of feed ) and butylenes yields (10 – 15 % wt of feed)

Novel catalyst formulation (IMX -50) for high yield of LPG , low coke , low dry gas and very high

vanadium tolerance .

very high catalyst / oil ratio coupled with high reactor temperature for severe cracking.

Wide flexibility in feed stock ( naphtha to heavy residue )

INDMAX COMPONENT

1> Component A : Medium pore Pentasil zeolite

2> Component B : consists of partially or fully ultra –stabilized Y-zeolite with specified rare earth

metals , active silica – alumina based matrix and binder.

3> Component C : Mostly contain large pore/mesoporous acidic non-crystalline active Matrix.

PROCESS OUTLINE

1> Feed storage and pumping section

2> Reactor and Regenerator section

3> Fractionation section

4> Gas concentration section

5> LPG/Gasoline Treatment section

Advantages of INDMAX technology

Up gradation of low value heavy hydrocarbons into high value LPG and high octane distillates.

Can process feedstocks 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.

Sulphur Recovery Unit [ SRU ]

H2S removed in the HDT , DCU and INDMAX process is sent to the sulfur recovery unit (SRU) as acid

gas. SRU recovers H2S as elemental sulfur through the Claus reaction .

Reactions occur in 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 sulfur recovery rate of the Claus process is about 95 to 97%.

The tail gas that contains unrecovered sulfur is fed to the tail gas treating unit (TGT). The recovered

sulfur is stored in the sulfur 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 COMPONENT

CLAUS train based on combustion of acid gas coming from ARU (amine 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 oxidize the residual H2S.

The flue gas leaving incinerator is discharge to atmosphere via a stack.

CLAUS REACTION

H2S + 3/2 O2 = SO2 + H2O + HEAT (MCC)

H2S + SO2 = 3/n Sn + 2H2O

NITROGEN PLANT

Nitrogen Generation Unit has been designed to meet inert gas required for all Catalytic

process unit and blanketing (off site) requirement for HSD , gasoline and CFO in ghy refine.

The New Nitrogen Plant at Ghy refinery is capable of generating Nitrogen of 99.99 %

purity in both gases and liquid form.

The process of generation of N2 is carried out in 3 steps in 3 different section of plant.

1> REFRIGRATION SECTION

For cooling of air from ambient to 10 oC

2> AIR PURIFICATION SECTION

for separation of moisture and CO2 content of the air.

3> AIR SEPRATION SECTION [ Cold Box ]

for further cooling and liquification of air and then separation of N2 from liquid air by

distillation in medium process distillation column.

SOURCE OF N2 PRODUCTION

Extraction of nitrogen from atmospheric air by distillation at low temperature is only

industrial process that is in vogue till date.

AIR OXYGEN NITOGEN

Critic Temp , oC -140.7 -118.9 -147.1

Critic Pressure , Kg/m2 38.45 51.76 34.6

LOW TEMPERATURE SOURCE

1> Heat exchanger

2> Heat Insulator

3> Free Expansion

4> Expansion with work output

SEPRATION OF COMPONENT OF AIR

The separation of air into its component is performed by means of distillation column.

This column operating at medium pressure separate pure liquid air into liquid N2 at top

position and liquid rich in oxygen ( about 40 % )at bottom. As this column and incoming

air heat exchange are to be operates at low temp , they are located in cold box . The air

before it enter the cold box for further cooling and distillation is cooled by refrigeration .

Purified from impurities like water , CO2 and certain hydrocarbon . These substance must

be eliminated otherwise water end oil form deposit in piping and passage . These causes

obstruction for flow .

HYDROGEN GENERATION UNIT

Hydrogen production has become a priority in current refinery operations and when

planning to produce lower Sulphur gasoline and diesel fuels.

It also supply Hydrogen to Hydro treating Unit (to meet out the centane specific in diesel

fuels ) and MSQU Unit (to meet the octane and aromatic specification of gasoline fuels )

HYDROGEN PLANT SECTION

1> Feed Treatment

2> Pre – reforming

3> Refining

4> Heat recovery

5> Shift

6> Product recovery

Before giving feed to Reforming tank , It is process through Feed Preparation train

where feed is heated to temp 320-370 oC . It remove moisture and undesirable

product in the feed. Reforming tank consists of 2 sections : Pre-reforming and

Reforming. Previous section yield 6-10 % H2 while later yield 70-80 % H2 thus amount

of CH4 , CO and CO2 decreases. Since CO is not ecofriendly, it is removed by Shiff

reaction. After processing through Shiff reactor , It is fed into PSA which result into

99.99 % yield of H2 . H2 thus produced , is directed to HDT ( major portion) and

isomer unit . Some amount is also self used into HGU.

SHIFF REACTION

CO + H2O = CO2 + H2

STEAM TO CARBON (S/C) RATIO

1> Pre- reformer S/C ratio

2> Over all S/C ratio

Design value for steam/carbon ratio is decided based on various factors, including:

Reformer tubes skin temperature;

Sudden fluctuations of feed gas composition;

Presence of higher hydrocarbons in reformer feed gas;

Distribution of duty between primary and secondary reformer;

Material of construction of reformer tubes, and;

Requirement of steam in CO2 removal section

MOTOR – SPIRIT QUALITY UNIT [MSQU]

Objective :

To split INDMAX gasoline and Wild Naphtha in the 3 cuts splitter and separate a heart cut stream .

To increase RON of Hydrotreated light naphtha cut in the Isomerization Unit.

To treat in NHDT , a mix of light naphtha heart cut from 3 cut splitter and straight Run Light naphtha

in order to produce a sulphur free stable naphtha to feed the isomerization unit.

NHDT SECTION

Purpose of this Naphtha Hydro desulphurization Unit is to protect Isomerization catalyst by

eliminating or reducing to an acceptable level the impurity of naphtha .

There are basically 2 fundamental reaction involve in this :

1> Hydro refining

2> Hydro generation

HYROREFINING

DESULPHURIZATION

Sulphides , Disulphides and mercaptas react readily with to produce corresponding saturation

and aromatic compound releasing H2S .

RSR' + 2H2 = RH + R

'H + H2S

RSSR' + 3H2 = RH + R

'H + 2H2S

RSH' + H2 = RH + H2S

DENITRIFICATION

R-NH2 + H2 = R-H + NH3

HYRDOGENERATION

C7H14 + H2 = C7H16

C8H14 + H2 = C8H16

CATALYST USED

1> HR -945 To protect against deactivation by unsaturation compound contained in cracked stock from

INDMAX unit.

To limit polymerization of Olefin and diolefins

2> HR -538

Desulphurization and Denitrification

PRODUCT YIELD :

1> Motor Spirit 90 wt %

2> LPG 10 wt %

MSQU process technology is used for production of blending stream of gasoline to meet

stringent quality of MS wrt benzene and aromatics content.

REFORMATE SPLITTER :

Split C6 and lighter species from the heavier reformate in the reformate splitter

Overhead vapor from reformate splitter is then condensed and collected in reformate splitter receiver.

PROCESS

Feed : Medium splitter cut from INDMAX and top product from Straight Run Light Naphtha (SRLN)

Before actual processing , feed is prepared by passing through various units :

Heater : It raise temperature of the feed and bring the feed's temperature to an equilibrium .

NHDT : it produce a sulphur free stable naphtha to feed the isomerization unit. It also saturate

olefins.

Stripper : It separate lighter gas like H2S into Stabiliser unit and heavy one into Drier section where

remaining water is vaporised .

BENSAT Reactor : benzene ring is converted into straight chain hydrocarbon.

ISOMER Reactor : It increases Octane number by converting straight chain into isomer unit.

Stabilizer : It separate off gas like HCL from motor spirit .

EFFLUENT TREATMENT PLANT

Industries wastewater 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 re-use. Most Industries produce some wet waste although recent trends in

the developed world have been to minimize such production or recycle such waste within the

production process. However , many industries remain dependent on process that processes that

produce wastewaters.

So Industries produce wastewater , otherwise known as effluent , as a bi-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.

TREATED EFFLUENT CHARACTERISTICS

PH 6.5 - 8.5

Oil < 5 ppm

Sulfide < 0.25 ppm

Phenol < 0.35 ppm

TSS <10 ppm

BOD <7.5 ppm

Design Flow

Wet Weather Flow ( WWF ) = 550 m3/hr

Dry Weather flow (DWF ) = 365 m3/hr

ETP SECTION

SEC 1

Physico – chemical Treatment for removal of Hydrocarbons , Sulphides and Total suspended solids.

SEC 2

Biological treatment system incorporating activated sludge system for oxidising the organic matter.

SEC 3

Tertiary treatment system comprising of pressure sand filter and activated carbon filters for treatment

removal of TSS , odour , color and phenol.

SEC 4

Sludge processing section comprises of oily and chemical sludge processing and disposal as a solid

waste biogradable material.

SEC 5

Chemical dosing system comprises of storage facilities of various chemicals and preparations of

chemicals solution of standard concentration for injection at various stage during effluent treatment.

API SEPRATION

Additional facility for separation of fuel oil from effluent and storage of waste oil effluent.

1> Blow down system

2> Dehydrating tanks

3> Oil settling basin

4> Emergency reservoir

5> Saintary water basin

6> Coke fine settler

7> API solid removal system

API SOLID REMOVAL SYSTEM

1> Thickener

2> Lagoons

CHEMISTRY OF EFFLUENT

POLLUTANT TREATMENT METHOD

1> Free Oil Gravity separation

2> Emulsified Oil Chem destabilisation and floatation

3> Sulphide chemical oxides

4> Organic (BOD/COD ) Biological oxidation and sedimentation

5> Settable solids sedimentation

6> Microbes Disinfection by chlorination

7> Suspended Solids sedimentation and filteration

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

1> Flash Mixer : Breaking oil emulsion and coagulate oil particles . It dose Acid ( HCL) whenever

PH of effluent is required to be adjusted.

2> Flocculation : Provided to flocculate the coagulation formed in flash mixing tank. polyelectrolyte

is added.

3> Airation Tank : Provide to remove biodegradable organics contributing to BOD/COD.

4> Polishing Section : Pressure sand filter are provided to remove the suspended solids and activated

carbon filter are provided to remove the odour , color and organic compounds to meet the treated

water quality (MINAS) for reverse in the refinery .

5> Sludge Thickner : This unit is provided to increase consistency of sludge for further treatment by

centrifuge.

HYDROTREATER UNIT Petroleum fractions contain various amounts of naturally occurring contaminants including organic sulfur,

nitrogen and metal compounds. These contaminants may contribute to increased level of air pollution,

equipment corrosion and cause difficulties in the further processing of the material.

The Union fining process is a properietery, fixed bed and catalytic process developed by

UOP for treating a wide range of feed stock. The process uses catalytic hydrogenation method to upgrade the

quality of petroleum distillate fractions by decomposing the contaminants with a negligible effect on the

boiling range of feed.

The desired degree of hydrotreating is obtained by processing the feed stock over a fixed

bed of catalyst in the presence of large amount of hydrogen at temperatures and pressures which depend

upon the nature of the feed and the amount of contaminant removal required. Naptha used as the feed stock to

catalytic reforming (PLATFORMING) unit must be hydrotreated to such an extent that they are essentially

free from all contaminants.

Unionfining units are designed for dependable,stable operation. UOP’s selective, high-

activity catalysts, operate for long periods of time between regenerations. Specific process objectives

determine which UOP catalyst is best suited for a particular installation.

BASIS OF DESIGN:

PLANT CAPACITY: The design throughput of the HDT is .6MMTPA with 8000 hours on-steam per year. The

turndown of the unit is 40% of design throughput.

FEED SPECIFICATIONS: HDT is normally be operated in two blocked out modes of operation: DIESEL and

KEROSENE. The unit on Diesel mode will process a blended feed containing straight run kerosene-2, straight

run gas oil, coker kerosene and coker gas oil with the below mentioned properties. Feed for the kerosene

operation will be the blend of straight run kerosene-| and ||, stream from crude oil. The unit can also process

neat cracked streams during diesel operation at 40% of its rated capacity. The unit will also have the

flexibility to produce AVIATION TURBINE FUEL (ATF) ifit is required.

HYDROTREATING CHEMISTRY:

The following chemical steps or reactions occur during the hydrotreating process.

SULFUR REMOVAL:- The typical feedstock to the Unionfining unit will contain simple mercaptan, sulphides

and disulfides. These compounds are easily converted to H2S. However feedstock containg heteroatomic

aromatic molecules is more difficult to process. Desulfurisation of the compounds proceeds by initial ring

opening and sulfur removal followed by the saturation of the rsulting olefin.

a) Mercaptan: C-C-C-C-SH + H2 -> C-C-C-C + H2S

b) Sulfide: C-C-S-C-C + 2H2 -> 2C-C + H2S

c) Disulfide: C-C-S-S-C-C + 3H2 -> 2C-C + 2H2S

d) Thiophenic:-

NITROGEN REMOVAL:- Denitrogenation is generally more difficult than desulfurization. Side reaction may

yield nitrogen compounds more difficult to hydrogenate than the original reactant. Saturation of

hydrogenation nitrogen containing rings is also hindered by large attached groups.

The reaction mechanism is:-

a) Pyridine:-

OXYGEN REMOVAL:- Organically combined oxygen is removed by hydrogenation of the carbon-hydroxyl

bond forming water and the corresponding hydrocarbon.

Phenols:-

OLEFIN SATURATION:-Olefin saturation reactions proceeds very rapidly and have a high heat of reaction.

a) Linear olefin:-

OIL MOVEMENT AND STORAGE DIVISION

Oil movement and storage division is the branch of production department. It is responsible for co ordinating

varios activities with the other agencies within and outside refinery. For instance OIL for supply of crude oil to

refinery. The Oil Movement & Storage (OM&S) and Utility sections cater to the storage and movement of crude oil

and products along with provision of generating and distributing steam, power, air and other utilities.

Functions of OM&S :-

1. Receipt, storage, accounting, preparation and supply of crude oil to DCU.

2. Receipt and storage of intermediate and finished products from production units.

3. Blending of products and chemical dozing.

4. Dispatch of finished products.

5. Measurement of petroleum products – gauging and sampling.

6. Filling and dispatch of LPG in bulk dispatches in bullets mounted on trucks.

OM&S Division is broadly classified into three sections as follows :-

1. Receipt and Blending Section

2. Dispatch Section

3. LPG Section

TANK NO.

SERVICE CAPACITY REFERENCE HEIGHT

SAFE HANDLING HEIGHT

FACTOR (kL/cm)

TYPE

7. Crude 5000 1184 1050 4.1 Fixed

80. Crude 5000 1620 1100 8.26 Floating

81. Crude 5000 1591 1196 8.28 Floating

82. Crude 5000 1612 1195 8.28 Floating