Training Report of Iocl

8/11/2019 Training Report of Iocl

1/71

1

A

TRAINING REPORT ON

INDIAN OIL CORPORATION LTD.

HALDIA REFINERY

DURATION - June 03, 2014 June 30, 2014.

PREPARED AND SUBMITTED BY:-

ANUPAM SRIVASTAV

DEPARTMENT OF CHEMICAL ENGINEERING

BUNDELKHAND INSTITUTE OF ENGINEERING ANDTECHNOLOGY, JHANSI -284128


2/71

2

Contents

Acknowledgement_________________________________03 Person to Whom Reported___________________________04 Preface__________________________________________05 Plant Overview ___________________________________05 Haldia Refinery Product____________________________07 Fuel Oil Block____________________________________09 DHDS Block_____________________________________18 Once Through Hydrocracker Unit Block ______________ 39 Lube Oil Block ___________________________________49 Oil Movement and Storage Block_____________________69 Conclusion ______________________________________71


3/71

3

ACKNOWLEDGEMENTS

We would like to express our heartfelt gratitude to the Training and Placementcell of Bundelkhand Institute of Engineering and Technology, Jhansi and Indian

oil corporation Ltd, Haldia management for providing us with the opportunity toundertake our in plant Industrial Training in one of the most technicallyadvanced and reputed refinery in India.

We would like to personally thank:

Mrs Mohua Basu,

Mr Amal Bikas Das,

Mr Sandeep Lahiri,

Mr Shantanu Kumar Sarkar,

Mr K.C.Mukherjee,

Mr P.K. Mandal,

Mr A. Mukherjee,

Mr Lallan Kumar Paul,Mr D.P. Chakraborty

And all the members of I.O.C.L. of Haldia refinery for making our trainingsuccessfully.

We would also like to thank all our respected and dear friends without whomguidance and help it would not have been possible for us to be successful in ourtraining.

Date: June 30, 2014.

Place: I.O.C.L. Haldia.


4/71

4

PERSONS TO WHOM REPORTED

Referred to :Shri. Shantanu Kumar Sarkar (CPNM):-Shri S. Lahiri (CPNM):-

Signature

A. B. Das

SO (MS, T&D)

NAME OF AREA I/C SIGNATURE OF AREA I/C

Fuel Oil Block:

Shri A. Mukherjee(SPNM)/Shri S.Choudhury(PNM )

Diesel Hydro De Sulphurisation Unit:Shri P. Adhikary (PNM)/Shri P.KMandal(DPNM)

Once through Hydro Cracker Unit:Shri K.C Mukherjee (SPNM)

Lube Oil Block:Shri L.K Paul (PNM)

Oil Movement & Storage Block:Shri D.P. Chakraborty(PNM)


5/71

5

PREFACE

This report is based on the project dissertation in I.O.C.L. Haldia I.O.C.L is oneof the most advanced plant in India for oil refining. I.O.C.L has been using

American, Japanese & Russian technology. The raw material that is used in plant is also imported from Arabian countries, transported by ship. Haldiarefinery was initially lube oil based refinery. Total production capacity of plantis 7.6 MMTPA.

This report is organised with various types of pressure, temperature, flow &Level measuring instruments & also D.C.S & P.L.C.

This report is in a sequence of unit overview process instruments, D.C.S &

P.L.C.

IOCL is the only Indian company, which is prestigious list of Fortune 500.IOCL stared its journey way back in 1959 Indian oil company Ltd. It becameIndian Oil Corporation limited in 1964. There are 7 refining running underIOCL and another one is under commissioning at Paradip.

The seven refineries are as follows:

1.

AOD, Digboi2. Guwahati3. Haldia4. Mathura5. Barauni6. Vadodara7. Panipat

Uniqueness of Haldia Refinery:

1. One of the Indias three lube oil refineries producing high grade lube basefeed stocks.

2. Incorporating 70% indigenous equipments for the first time in India.3. Indias only refinery producing Bright stock -a lube oil base stock for

making lube oil which is used in heavy duty equipment.4. First Indian refinery to receive ISO-9002 certificate.

PLANT OVERVIEW

The refinery manufactures fuel products & HVI grade lube oil base stocks.


6/71

6

The refinery has the following units:

FOB(Fuel oil block) LOB(Lube oil block)

DHDS(Diesel hydro desulphurization unit) OHCU(Once through hydrocracker unit) OM & S(Oil movement and storage) TPS(Thermal power station) Workshop Quality control and Laboratory ETP(Effluent treatment plant) MIS(Management information system) Training centre IMA(Indian oil management academy at Township)

FOB compromises of following units:-

1. Crude Distillation unit(CDU-1,CDU-2)2. NAHDT3. Catalytic reforming unit(CRU)4. Kerosene Hydro Desulphurization unit(KHDS)

LOB comprises of the following units:-

1. Vacuum Distillation Unit(VDU)2. Propane De Asphalting Unit(PDU)3. Furfural Extraction Unit(FEU)4. Solvent De Waxing Unit (SDU)5. Lube Hydro Finishing Unit(LHFU)6. Bitumen Treating Unit(BTU)7. Vis Breaker Unit((VBU)8. Micro Crystal Wax(MCW)9. Nitro Methyl Pyrolidyne(NPM)

DHDS comprises of following main units:-

1. Hydro generation unit2. DHDS

3.

Sulphur Recovery unit(SRU)4. Amine Regeneration Unit(ARU)


7/71

7

5. RFCCU(Regeneration fluidised Catalytic Cracking Unit)6. MSQL(Motor Spirit Quality Up gradation)

OHCU comprises of following Unit:-

1. Hydro Cracker2. Hydrogen Generation Unit3. Nitrogen generation Unit

OM &S is subdivided into following sections for operating convenience:-

1. Crude tanker unloading2. Crude tank farm3. LPG storage4. LPG bottling plant5. Tank wagon loading6. Tank truck loading7. Bitumen filling station drum and pack8. Solvent tank firm

HALDIA REFINERY PRODUCTS

1. Liquefied petroleum Gas(LPG)2. Straight run naphtha(SRN)3. Motor spirit(MS)4. Bitumen5. Superior Kerosene oil

6. Aviation Turbine Fuel(ATF)7. Russian Turbine Fuel(RTF)8. Mineral Turpentine oil(MTO)9. High speed diesel(HSD)10. Jute Batching Oil (JBO)11. Light Neutral Lube oil base stock (LN-LOBS)12. Bright Neutral Lube oil base stock (BN-LOBS)13. Fuel gas

14. Slack wax inters neutral (IN-SW)15. Slack wax Bright neutral (BN-SW)


8/71

8

16. Carbon block feed stock (CBFS)17. IOC process oil


9/71

9

FUEL OIL BLOCK

CRUDE DISTILLATION UNIT

INTRODUCTION:-

The crude distillation unit at Haldia Refinery was designed for processing of 2.5MMTPA of Agajhari crude with a processing rate of 7500 MT per dayconsidering 8000 on stream hrs. per Annum. The unit was debottlenecked inDec84 to 2.75 MMTPA by minor modifications. After that trays and columninternals replacement was undertaken in May88 with the help of M/S EIL to

suit the column to process 3.16 MMTPA.

Subsequently a prefractionator column was installed in May96. With theaddition of the prefractionator the capacity of CDU has increased to 10500MT/Day of upper Zakum or Arab mix crude which is equivalent to 3.5 MMTPAconsidering 8000 stream hours per year.

Crude distillation (Unit No 11) includes

Pre fractionator section Topping section

Naphtha Stabilizer Naphtha Redistillation

Gas plant (Unit No 12) includes

De-ethaniser Amine washing of LPG

Depropaniser

Amine Absorption & Regeneration unit (unit no.15)

Fuel Gas Amine Absorption system Amine(DEA) Regeneration


10/71

10

PRINCIPLE OF OPERATION

Crude oil is heated to 120 1300C in the first set of pre heat exchanger before feeding to the Desalter.Crude is desalted to the extent of 95% in

the Desalter. Crude is there after heated to approximately 180-200 C inthe second set of heat exchangers and pretopped in the Prefractionatorcolumn to get overhead gasoline from the top(IBP-140) and pretoppedcrude from the bottom of the column. Again crude is heated to 260-265 Cin the third set of exchangers and 350-360 in the furnace. The crude oil isthen fractionated in the atmospheric distillation column (11C01) to obtainthe following streams.

Refining of overhead (IBP-140C cut)

a) IBP-140 C cut is fractionated in stabilization column into two products. Very low boiling hydrocarbon portion upto BUTANE/BUTENE is

obtained from overhead and routed to gas plant. C5-140 cut is obtained from bottom and routed to Naphtha

Redistillation column. b) Gas plant stabilizer overhead product is first distilled in De-ethaniser for

separation of ethane. 12C01 overhead stream, rich in ethane, is sent to

fuel gas system of refining. De-ethaniser bottom is Amine washed incolumn 12C02 for removal of H 2S and then routed to Merox(unit-13) formercaptan removal. Crudes presently being processed contain low H 2S inLPG range and Amine washing is not required. Hence the column 12C02is by-passed.

c) Merox Treatment: LPG from Gas plant is caustic washed and then sent toLPG extractor (13C01) where it comes in counter current contact withMerox catalyst dispersed in caustic solution. Mercaptan free raffinate

LPG, after caustic separation is sent to LPG storage.d) Propane production: A part of Merox treated LPG is fractionated in De-

propaniser column of gas plant to produce PROPANE of around 8-10MT/Day depending on its requirement at Propane deasphalting unit inLube oil block.

e) Spiliting of C5-140 C cut:In Naphtha Redistillation column C5-140 C portion is fractionated intoC5-90 and 90 to 140 C cut, i.e light naphtha and heavy naphtha.

f) Kerosene/ ATF/ MTO/ RTFg) Gas oil


11/71

11

CATALYTIC REFORMING UNIT

INTRODUCTION

The operating manual describes all necessary procedures for the start-up,stable& safe operation and shut down of the CRU (Catalytic ReformingUnit). The unit was built by M/S Technip using a process licensed jointly

by Indian Institute of Petroleum, India and Institute Francias du petrole,France for processing 196 TMT of Naphtha with a stream factor of 8200hours.

In August-Sept 2005 a major revamp was carried out, with process

licensed by M/S Axens of France, to increase capacity, enhance productquality.In June-May 12 M & I was carried out with the complete replacement ofcatalyst with UOP platforming catalyst to meet Euro-IV requirements.This manual has been made in pretext of CRU12 catalyst replacement.The purpose of the catalytic reforming unit is to improve octane numberof hydro treated gasoline, producing a total reformate cut(min.RONC 97)with minimum guaranteed yield of 84.4 wt% (SOR) and 83.3 wt% at

EOR with reformate of 0.60 kg/cm2

RVP and hydrogen rich gas. Theunit capacity after 2005 revamp was 216 MT/Yr, with an on stream factorof 800 hours. In the revamp, the first old axial reactor has been removedand a new radial reactor has been put on service as third reactor. Also, thesecond old interheater has been removed and a new heater put on serviceas a first interheater.

BATTERY LIMIT AREA:

PROCESS DESCRIPTION:


12/71

12

Preheat section:

Naphtha distillate from storage tank is fed by pump to magnetic filter,where the metallic particles are removed. The foreign material present in

the feed are separated out and fouling in the preheat exchanger isreduced. Then it is mixed with H 2 , make up gas from reforming unit andrecycle gas discharge by compressor and is heated to about 360 0c in a

preheat exchanger(packinox Exchanger)In the shell side where it is heated by hot reactor effluent.

Furnance and Reaction Sections

Completely vaporised naphtha and gases, after passing through the firstfurnance is heated to the reaction temperature , enter at the top of the firstdown flow peactor.Operating pressure = 27.3 kg/cm 2gOperating temperature =512 0 CThe reactor is filled with a bimettalic platinum rhenium catalyst supporton very high purity alumina. When the feed come in contact with catalystreforming reaction take place .due to endothermicity of reaction, thetemperature of reactant decreases. The effluent from the first reactor istherefore, reheated in a second furnance to make up the loss of heat in thefirst reactor.Operating condition for the second reactor:Operating pressure =26.3kg/cm 2 Operating temperature = 512 0CReheated effluent is then passed through the second reactor containing

platinum rhenium catalyst where further reforming reactions take place.Effluent from the second reactor is again reheated in furnace and passed through reactor containing the catalyst to complete the reformingreactions for obtaining the product with desired octane number.

Reactor effluent cooling system

The effluent from reactor is cooled and partially condensed in aseries of exchangers as follows.

In the tube side of exchanger to preheat feed and to reboil stripper bottoms


13/71

13

In the packinnox exchanger to preheat feed In shell side of the water coolerThe effluent thereafter is sent to the separator drum.

Separator Drum and recycled Gas section

The reactor effluent is split into gaseous and liquid phases in separatordrum.

The liquid phase is sent to stripper column Apart of gaseous phase is recycled as recycle gas within CRU Another part is sent to make up to Naptha Pretreatment section Remaining to KHDS section

The hydrogen rich gas from the separator drum is recycled by means ofthe centrifugal compressor. Part of the compressed gas is mixed with the

preheated naptha as described earlier.

Stabilizer section

The liquid from the separator drum is fed to the stabilizer . The liquid

is reheated in the shell side of the exchangers with the stabilizer bottom product on the tube side and the enters the stablizer .

A part of the stabilizer bottom product is reboiled in thermosyphon typeexchanger.

The stabilizer overhead vapours are cooled and partially condensed bycondenser and are collected in the overhead horizontal reflux drum.

The stabilizer bottom part is passed through exchangers and cooler beforeit is sent to storage and feed to reformer splitter.

The top product from the stabilizer is sent to reflux drum where the gasstream is separated from the top of the drum and sent to fuel gas orM.S.Q.U unit . Apart of the liquid is pumped back into the stripper whilethe other consist of LPG to rundown.


14/71

14

KERO HYDRO DE SULPHURISATION UNIT (KHDS)

INTRODUCTION:

This describes all the necessary procedures for the start-up, operation andshut down of 577,500 TPA Kerosene Hydro Desulphurisation Unit.Installation of mounted APH with FD fans and replacement of existingnatural draft burners with forced draft low NOx and low excess air

burners in KHDS furnace has not only increased the overall efficiency ofthe furnace but also net savings in terms of capital cost by removing FOconsumption in the furnace. This unit was built by TECHNIP and it usesa process licence jointly developed by Indian Institute of Petroleum andInstitute Francis Du Petrole, France.

UNIT CAPACITY:

The Kero Hydro De Sulphurisation unit is designed for 577,500 tons peryear capacity with 8200 on stream hours.


FEED AND GAS PRE HEATING SECTION

Raw Kerosene/MTO/ATF feed from the storage is taken to the unitthrough 23 FCV 01 by a pump 23 P OI A/B. The feed is subsequentlymixed with recycle gas available from discharge of the compressor 23 K01 A/B/K-101A which is taken as make up hydrogen to its suction exCRU/DHDS. Both, liquid feed and gas streams are heated in heatexchangers 23 E 02 D C B A in the shell side while the hot reactoreffluent passes through the tube side.

Hot mixture of liquid and gas from 23 E 02 D C B A is taken to thefurnace 23 F 01.

FURNACE AND REACTOR SECTION

Pre heated Kerosene/MTO/ATF/RTF and recycle gas mixture is broughtto the reaction temperature in the furnace 23 F 01. The furnace is installedwith a top mounted APH with FD fans 23FD01 A/B were replaced withnatural draft burners forced draft low NOx and low excess air burners.

The modification in furnace was done in the view of savings in FO


15/71


16/71

16

The separator drum is connected to an ejector to create vacuum in the unitduring start-up& shut down. The recycle gas along with the makeup gasis compressed by parallel reciprocating compressors.

The make-up hydrogen gas from CRU/DHDS comes to the suction ofrecycle gas compressors through a knock out pot.

STRIPPING SECTION

The liquid from the separator drum is pre heated in the exchangers 23 E04 A/B and fed into the stripper column 23 C 01. This stream passesthrough the lube side and recovers heat from the treated product throughthe shell side.

The column consists of:

- 17 ballast trays, type two pass below the feed point and - 8 ballast trays, type single pass above the fee d point.

A part of the stripper bottom is reboiled in the heat exchangers 23 E 01on the shell side recovering heat from the reactor.

RECOMPRESSING SECTION

The gas from the reflux drum, 23 B 02 goes via 23 B 02A to first stage ofthe three parallel reciprocating compressors. A high level alarm is

provided in 23 B 02A.

In case 23 K 02 A/B in line:

The first stage discharge gas upon cooling in the water cooler is mixedwith the gaseous stream ex LOB/U-11 PF column/U-16 PF column

before sending to the knock out drum 23 B 04.Off gas stream of U-37(LOB) can be diverted directly to 15CO2

bypassing U-23 using the jump over at battery limit.

The condensed hydrocarbons from the drum are sent to stripper columnregulated by the high level controller 23 LC 14. This drum is providedwith the high level alarm 23 LAH 13. The vapour from the knock outdrum are compressed in the second stage of the compressors cooled in a

water cooler 23 E 08 sent to the knock out drum 23 B 05. The vapours


17/71

17

separated from the liquid hydrocarbon are sent to the fuel gas or amineunit.

CHEMICAL INJECTION

CORROSION INHIBITOR DOSING OF ADDITIVES IN ATF RUN.


18/71

18

DHDS BLOCK

DHDS block comprises of following main units:-

1. DHDS2. RFCCU3. ARU4. SRU5. MSQU

DIESEL HYDRO DESULPHURISATION UNIT

Purpose:

To reduce the sulfur content of the sour diesel and to produce sweet diesel with sulfur content of less than 0.25/0.05 % by wt.

Sulfur removal:

Feed stocks to the union fining .Unit contain simplemercaptanes, sulfides anddisulfides are easily converted to H2S. Feedstocks containing hetero atomic,aromatic molecules are preceded byinitial ring opening and then sulfur removalfollowed by saturation of theresulting olefins.

Nitrogen removal:

De-nitrogenation is generally more difficult thandesulphurization. The de-nitrogenation of pyridine proceeds by aromaticring saturation hydrogynolysis andfinally de-nitrogenation.

Oxygen removal:

Organically combined oxygen is removed by hydrogenationof the carbon hydroxyl bond forming water and the correspondinghydrocarbon .Olefin saturation: Olefin saturation reaction proceeds varyrapidly and have high heat of reaction.

Aromatic saturation:

Aromatic saturation reaction is the most difficult and exothermic.


19/71

19

Metal Removal:

Metals are retained on the catalyst surface by a combinationof adsorption and chemical reaction. Removal of metal normally occurs

from the top of the catalyst bed and the catalyst has a certain maximumtolerance for retaining metals.

Metal contained in the crude oil are usually nickel andvanadium. Iron is found concentrated at the top of the catalyst bed as ironsulfide, which is corrosive. Na, Ca and Mg are present due to the contactof the bed with salted water or additives.

Improper use of additives, to protect the fractionator

overhead systems from corrosion or to control foaming, accounts for the presence of P and Si. Lead may also deposit on the hydro treating catalyst bed from reprocessing leaded Gasoline through the crude unit. The totalmetal retention capacity of the catalyst system can be increased by usinga guard reactor or guard bed of catalyst specially designed for de-metallisation.

Halide removal:

Organic halides such as chlorides and bromides aredecomposed in the reactor.The inorganic ammonium halides sides, whichare produced when the reactoreffluent is cooled, are dissolved binjectingwater into the reactor effluent or removed with a stripper off gas.

Process Description:

The DHDS unit is based on the diesel union fining process of UOP andiscomprised of four main section

The feed section Reactor circuit section Separator or compressor section Fraction section

Feed Section

The feed stocks consisting of mainly straight run gas oils and lightcycle

oil from FCCU from Storage first passes through feed filters andfeedexchangers heated by stripper bottoms material before entering a


20/71

20

combinedfeed coalescer and surge drum. The feed surge drum providessurge volume to even out the fluctuationsin the feed entering the unit.This surge volume allows the feed to the unit tobe kept as constant as

possible which maximize the catalyst life length. Feedfrom the feed surgedrum enters the feed pumps where its pressure is raised to allow the feedto enter the reactor circuit. Feed from the feed pump is combined with therecycle gas flow .Combined feed passes through cold and hot combinedheat exchangers where it is heated by reactor effluent material .Then thefeed is sent to the charge heater where it enters the reactor circuit sectorsection.

Reactor circuit section

Combined feed from the feed section is heated to reactiontemperature in the charge heater. Then the feed and recycle gas are

proceeded in reactor 1and 2 which contain catalyst chosen for its abilityto absorb metal in the field and to provide the proper level ofdesulphurization required to meet a specified diesel product property.

The reactor 1 has two beds with one intermediate quench point.Quench isrequired due to the heat of the reaction and the need to limit the

temperature rise to maintain the proper catalyst cycle length for thechosen space velocity

The reactor 2 is a single bed reactor. To monitor the operation of thereactors bed, thermocouples are providing at regular intervals. Reactoreffluent material is cooled in the hot combined feed exchanger .Water isinjected into this stream before it enter the separator condenser. Aftercooling to the appropriate temperature, this is separated in the separatorinto vapor and liquid hydrocarbons phases to decant the sour water phase.The vapor from the separator is cooled in recycle gas cooler beforeentering the scrubber KO drum.

The purpose of the recycle gas exchanger is to decrease the due point ofthe recycle gas so as to greatly lessen the possibility of condensinghydrocarbons material in the recycle gas scrubber, such HCscondensation contributes to the foaming of the amine.


21/71

21

Process Flow Diagram:

REGENERATION FLUIDISED CATALYTIC CRACKING

UNIT

Introduction:

Indian Oil corporation limited (IOCL), Haldia Refinery has set up a

700,000 metric tons per annum capacity Fluid catalytic crackingunit(FCCU) at Haldia,West Bengal.The new plant mainly consist of reactors, regenerators, mainfractionators, product recovery section including amine treatingfacilities Cracking reaction cracks down the long chain highermolecular weight hydrocarbon into the lighter molecular weighthydrocarbon .In course of cracking reaction, coke is also producedwhich remains on the catalyst particles and rapidly reduces its

surface activity. In order to maintain the catalyst activity at a usefullevel, it is necessary to regenerate the catalyst by burning off the


22/71

22

deposited coke.To achieve this , the catalyst continuously flowsfrom reactor to regenerator, where coke is burnt off in the presenceof oxygen.

Cracking Processes:

Cracking is a phenomenon by which large oil molecules aredecomposed into lower boiling molecules. At the same time certainof these molecules, which are reactive, combine with one anotherto give even larger molecules than those present in the originalstock.In modern refining industries there are three basic processesfor the conversion of heavy oil into useful products namely thermalcracking, fluidised catalytic cracking and hydrocracking.

Process Description

Process Chemistry Theory:

Cracking process uses high temperature to convert heavy

hydrocarbons into more valuable lighter products. This can be doneeither by thermal cracking or catalytic cracking. Catalytic cracking process has almost superimposed thermal cracking because ofinherent advantage of low temperature and pressure. Catalyticcracking produces higher octane gasoline, a more valuable crackedgas and less of undesirable heavy residual products. Theory ofcatalytic cracking is based on carbonium ion formation andsubsequent hydrogen transfer reaction.

Brief Process Description:

Fluidised cracking unit consists of the following sections:

1. Feed preheat section2. Reactor/Regenerator section3. Flue gas section4. Catalyst Handling section5. Main fractionators section


23/71

23

6. Product recovery section7. Amine treating section

Feed Preheat Section-Cold feed from FCCU feed tank and hot feed from process unitsare combined and received feed surge drum, cold feed enters feedsurge drum on level control and hot feed enters surge drum on flowcontrol.A water boot on the drum allows for manual draining of any water,which may accumulate during start up upset conditions.The feeddrum pressure floats on the main fractionator by means of a

balanceline which ties into the fractionators below the LCO drawchimney tray.

AMINE REGENERATION UNIT

Introduction:

Indian Oil Corporation Ltd. (IOCL) Haldia Refinery has DieselHydro De Sulphurisation Unit (DHDS) for meeting the H 2Sremoval application for 2000 AD. To meet the requirement a new

Amine Regeneration Unit (ARU 26) is installed. The function ofthe unit is to supply lean amine to and regenerate rich amine fromvarious users located in the DHDS unit. The ARU consists of 4sections the rich amine section, the amine regeneration section, thelean amine section and the amine storage section. The acid gasfrom the ARU overhead is routed to the SRU and the lean amine tothe DHDS unit Rich amine from Catalytic DE waxing unit shall berouted to ARU to meet this enhanced load minor revamp is done.

Design Basis:

Unit Capacity:-

Design Capacity - The design capacity of the ARU is 118526kg/hr. Increased load due to CDWU is 20176 kg/hr.

Turn down Capacity- The turndown capacity of the ARU is50%.

On Stream Factor- The on stream factor per year is 8000hours.


24/71

24


Battery Limit Conditions-

Feed Characteristics: -

Product Lean Amine toDHDS

Acid Gas

Temperature OC 43.3 40Pressure kg/cm 2g 12.5 1.0

Feedstock Rich Amine

Ex DHDS

Temperature OC 50.4

Pressure Kg/cm 2g 2.04

Rich Amine ex DHDS unit and CDW unit

(Kmol/hr)

DHDS Unit CDW Unit

H2O 4837.20 806.20DEA 276.37 46.03H2S 90.210 14.79

H2 0.175 ----CH 4 0.029 0.005C7H6 0.044 0.064C3H8 0.009 0.011C4H10 0015 0.025C4 0019 0.004

Total */ 5203.96 876.05


25/71


26/71

26

amine from the bottom of amine stripper 26-C-01 is cooled. The heatedrich amine flows through the control valve LV-6202(used to control thelevel in 26-V-01) and into 26-C-01. Stripper 26-C-01 strips nearly all ofthe H 2S from the rich amine, thus regenerated it to lean amine. Thestripper contains 23 valve trays with which 20 trays in the strippingsection and 3 trays in the wash section. Stripping steam is generated inthe Amine Stripper Reboilers 26-E-03 A/B by vaporising a portion of thewater in the column bottoms (lean amine). A small amount of livestripping stream is also injected into one the re-boiler return lines (14-P-26-6511) in order to water balance the entire amine system. The strippingstream flows up through the column, helping to evolve H 2S from the richamine and heating the solvent to boiling point. Reboilers 26-E-03 A/Buse de superheated MP stream as the heating medium. The re boilerheating rate is controlled by low selector FY-6502B of steam flowcontroller FIC-6502 and pressure controller PIC-6507. The absolutemaximum temperature of the de superheated steam is 160OC in order to

prevent amine degradation Condensate from the re-boilers condensatereturn system is used as the water source to de-superheat the reboilersheating steam. Condensate from 26-E-03 A/B flows to condensate Drum26-V-04.Whatever is not used for de superheating water or as makeupwater to the Diesel Union fining Unit is pumped to the condensate headerwith condensate pump 26-P-04 A/B under level control(LIC-6601).Acid gas from the top of 26-C-01, containsH 2S, some light hydrocarbonsand water vapours is cooled to drop the temperature (Condensing most ofthe water) to minimise the water loss in the overhead in this overheadsteam. The gas is first cooled in Amine Stripper Condenser 26-AC-06 andthen further cooled in Amine Stripper Trim Cooler 26-E-04. The two

phase stream flows to Amine stripper Receiver 26-V-02 where the wateris separated from the remaining acid gas steam. The water from 26-V-02is pumped via Amine stripper Reflux pump 26-P-03 A/B as reflux back tothe top tray of 26-C-01. The acid gas from the top of 26-V-02 is normallyto the SRU. At shut down of the SRU or if the SRU is not in operationacid gas is sent to the acid gas relief header through pressure controlvalve PV-6505B. Theacid gas pressure is controlled with pressure controlvalve PV-6505 via a split ring configuration at a pressure of 1.77kg/cm 2g. The bottom of 26-C-01 is used as a surge volume for lean amineto a temperature (43.3 OC), which can be used by the amine scrubber and


27/71

27

absorbs in the Diesel Union fining Unit. The outlet temperature of 26-E-01 is kept from getting too low by temperature controller TIC-6402. Thisacts on the lean amine by pass around the trim cooler. The lean aminethen flows to the filtration system, which filters approx. 10% slipstreamof lean amine through a sense of three filters.

Lean Amine Section- Some lean Amine is used inside the amine unit battery limits as a wash for the Rich Amine flash Drum stack them is alsoa start-up line, which allows lean amine to be re-circulated through theregeneration section only, flowing back to 26-V-01. The remainder of thelean amine then leaves the Amine unit and serves the absorbers in theDHDS Unit. These absorbers include: the Recycle Gas Scrubber locatedin the Reactor section and the Stripper Gas Amine Absorber located inthe Reactor Section and the Stripper Gas Amine Absorber located in theFractionating Section. The Reactor section scrubber operates at asignificantly higher pressure than the other absorber, so a booster pump isrequired to supply the lean amine at a sufficient pressure for the RecycleGas Scrubber. This pump is located in the Diesel union fining Unit.

Amine Storage Section- High purity amine (99 wt.% DEA) is tosupplied to ARU 26 in bulk quantity (for s/u) and in drums. The AmineMelt Tank 26-V-07 is used to empty drums and to melt the amine. Themelted DEA or the DEA in bulk quantity is transferred to Amine StorageTank 26-T-01 via Amine Transfer Pump 26-P-07 A/B and is diluted to a25 wt.% solution in water with cold condensate from the refinery as watersource. This pump can also be used to mix the contents of 26-T-01through a recirculation line with a jet mixer located inside the tank. The25 wt% DEA Solution in water is periodically pumped (via 26-P-07 A/B)to the regeneration section to replenish the amine supply. The amine can

be pumped to the suction of Lean Amine Pump 26-P-02 A/B and thesuction of Rich Amine Pump 26-P-01 A/B. Addition of amine will resultin an increase in the level of Amine Stripper 26-C-01. Amine storageTank 26-T-01 is also used to old the entire inventory of the RegenerationSection, when it needs to be shutdown. The pump out line is on the leanamine stream just downstream of the Lean Amine Coolers. The cooledlean amine is transferred over to 26-T-01 via 26-P-02 A/B and can bereplaced using 26-P-07 A/B when the train is ready to be re-inventoried.


28/71

28

SULPHUR REGENERATION UNIT

Introduction :

The sulphur recovery unit-28/83 of haldia refinery consists of asingle train to recover sulphur from acid gases from amineregeneration unit(UNIT-26) and sour water stripper off gases exrefinery sour water stripper(UNIT-29).This unit based on clausrecovery concept.It is consisting of one thermal reactor and fourcatalytic converters for recovery of sulphur from abovestreams.The equipments in the unit shall be divided into three mainsections, namely the thermal reactor section ,claus section and tail

gas incineration section.The sulphur recovery section shall includeknock out drums for various inlet streams,a main burner,a maincombustion chamber,a waste heat boiler, sulphurcondenser,catalytic converter-1,catalytic converter-2,catalyticconverter-3,and super claus catalytic converter,a sulphur pit tostorage liquid sulphur,sulphur pumps,pit ejector etc.The tail gasincineration section includes thermal incinerator burner and ventstack for disposing of the flue gas from incinerator containingsulphur dioxide.Flue gases produced by incinerating the tail gasesshall be vented through stack to disperse the sulphur dioxide.Stackis designed for two trains each of 60TPD sulphur capacity.Aminimum stack height of 50m is provided.Sulphur recovered in the

process is stored in the pit and is pumped to a yard where sulphurlumps are produced by quenching the ,molten sulphur using servicewater.

Sulphur Recovery Rate:

The unit is capable of a sulphur recovery rate of 99 wt% based on operation of the unit at a capacity and acid gascomposition corresponding to one of the cases as defined.

Unit Capacity:

Design Capacity-

The unit consists of one SRU with a sulphur production capacity of 60metric tons/day.


29/71

29

Turndown Capacity-

The turndown of the unit is 30% on the normal feed gas rate.

On-stream Factor per year is 8000 years.

Design Feed Chsrscterstics

The feed stock of the SRU is a mixture of the acid gas ex ARUand the Acid gas ex SWS,the unit should be capable ofconverting 99% wt of the hydrogen sulphide contained in the feedstreams to sulphur in all the following cases.

Case-1, design case

Design Product Characteristics

The product sulphur will meet the following specification after degassing

State : liquid sulphur Colour: bright yellow(as solid state) Purity: min 99.9wt% on dry basis

acid gas ex-ARU(kg/h)

acid gas ex-SWS(kg/h)

total feed(kg/h)

waterhydrogen

sulphideammonia

hydrogen

methaneethane

prpopane butane pentanecarbondioxide

Total

64.102658.80-0.303.38

1.360.321.271.71-

2731.24

34.1058.8216.49--

-----

109.41

98.202717.6216.490.303.38

1.360.321.271.71-

2840.65


30/71

30

Hydrogen sulphide content: 10ppm weight max.

Process Summary:

The sulphur recovery process applied in design,which is known as theSUPERCLAUS process, is based upon the partial combustion ofhydrogen sulphide (H 2S) with a ratio controlled flow of air, which ismaintained automatically in a correct quantity to accomplish the completeoxidation of all hydrocarbons of 0.5-0.7vol% at the selective oxidationreactor(SUPERCLAUS reactor).

In the conventional claus process the air to acid gas ratio is mainted to produce an H 2 S/SO 2 ratio of exactly 2/1 in the burner effluent gases.This is

known to be the optimum ratio of H 2 S/SO 2 for the claus reaction.In this process the air to acid gas ratio is adjusted to achieve an H 2 S/SO 2 ratioof greater than 2/1 in the burner effluent.

In the other words , the front end combustion is operated on H 2 S/SO 2ratio control H 2S-SO 2 analyzer AT-0801 is provided on effluent gasstream from the 4 th sulphur condenser to measure the H 2S concentrationand to control the trim air to the main burner to achieve the desired H 2Sconcentration at this point in the process.From an overview standpoint,the control philosophy may be summarized as :

If the H 2S concentration entering the SUPERCLAUS stage is toohigh , more air is added to the main burner to create more SO 2 .

If the H 2S concentration entering the superclaus stage is too low,less air is added to the main burner.

Process Description :

H2S + 3/2 O 2 -> SO 2 +H 2O +heat

The major part of residual H 2S combines with SO 2 to form sulphur,according to the equilibrium reaction

2H 2S +SO 2 < -> 3/2 S 2 +2H 2O - heat

By this reaction , known as the claus reaction,sulphur is formed invapourphase in main burner and combustion chamber .The primary


31/71


32/71

32

SUPERCLAUS SECTION

The process gas from the 4 th sulphur condenser is routed to the 4 th steamreheater, then passed to the reactor.Before it enters the reactor a

controlled amount of air is added.Proper mixing isobtained in in a staticmixer .In the reactor H 2S reacts with oxygen to sulphur according to thereaction.The sulphur is condensed in 5 th sulphur condenser.The sulphurcoalesce is installed downstream of the last sulphur condenserto separateentrained sulphur mist.The sulphur condensed and separated in thecondensers and coalesce is drained via the sulphur locks and sulphurcoller in the sulphur pit.

SULPHUR STRIPPING PROCESSThe produced sulphur contains H 2S,partly dissolved and partly present inform of polysulphides.The function of this process is to enchance thedecomposition of polysulphides and to strip the H 2S from sulphursimultaneously the greater part of H 2S is oxidized to sulphur.This is done

by bubbling air through the sulphur. The air decreases the partial pressureof the H 2S and causes agitation and circulation of sulphur.In this way theH2S content is reduced from approximately 350 to less than 10 ppm wt.

PROCESS FLOW DIAGRAM:


33/71

33

MOTOR SPIRIT QUALITY UPGRADATION UNIT(MSQU)

INTRODUCTION:

Process Chemistry Overview: Thermodynamics and kinetics- For any chemical reaction, the

thermodynamics dictates the possibility of its occurrence and the amountof products and unconverted reactants. In fact, some reactions are 100%completed i.e. all the reactants are converted into products. Other are inequilibrium i.e. part of the reactants are only converted. The amount of

products and reactants at equilibrium depends upon the operatingconditions and is dictated by the thermodynamics. Note that thethermodynamics does not mention the time required to reach theequilibrium or the full completion of a reaction. Kinetics dictates the rate of a chemical reaction (i.e. the amount of feedthat disappear in say, one second). Kinetics (rate of reaction) is dependentupon operating conditions but can also be widely modified through theuse of properly selected catalyst.In other words thermodynamics dictates the ultimate equilibriumcomposition assuming the time is infinite. Kinetics enables the predictionof the composition after a finite time. Since time is always limited, whenreactions are concurrent, kinetics is generally predominant.A catalyst generally consist of a support (earth oxide, alumina, silica,magnesia) on which finely divided metal(s) is/are deposited. The metal isalways responsible for the catalytic action. Very often the support hasalso a catalyst action related to its chemical nature.

Catalyst activity, selectivity, stability-The main characteristics of a catalyst other than its physical andmechanical properties are:

The activity which is the catalyst ability to increase the rate of thereactions involved. It is measured by the temperature at which thecatalyst ability I increased the rate of the reactions involved. It ismeasured by the temperature at which the catalyst must be


34/71

34

operated to produce a product on specification, for a given feed, allother operating conditions being equal.

The selectivity expresses the catalyst ability to favour desirablereaction rather than others.

The stability characteristics the change with time of the catalyst performance (i.e. activity, selectivity) when operating conditionsand feed are stable. It is chiefly the polymers or coke deposit whereaffects stability, because it decreases the metal contact area. Tracesof metal in the feed also adversely affect stability.

Chemical Reaction- The purpose of the Naphtha Hydro treatment unit isto protect the isomerisation catalyst by eliminating or reducing to anacceptable level the impurities present in the naphtha stream. Impuritiessuch as sulphur, nitrogen, water, halogens, di-olefins, olefins, mercury,arsenic and other metals are detrimental to catalytic activity. Thetreatment process is achieved by passing the naphtha over a bimetalliccatalytic bed in an adiabatic reactor in the presence of hydrogen.There are principally two fundamental reactions occurring:-Hydro refining-Hydrogenation

Hydro refining:This refers to the replacement of the contaminant molecule withhydrogen. Major hydro refining reactions include desulphurisation,denitrification and de- oxygenation. These are explained in sectionsthat follow.

a) Desulphurisation:Sulphides, disulphides and mercaptans react readily to

produce the corresponding saturated or aromatic compoundreleasing H 2S.RSR + 2H 2 RH+RH+H 2SRSSR+3H 2 RH+ RH+2H 2SRSH+ H 2 RH+ H 2SSulphur combined in an aromatic structure like thiophene ismore difficult to react.

b) Denitrification:This reaction occurs at a slower rate than desulphurisation.Here nitrogen is released to form ammonia.


35/71

35

R-NH 2 + H 2 R-H + NH 3 c) De- Oxygenation

Similar to denitrification, de- oxygenation reactions aremuch more difficult than desulphurisation. Oxygenatedcontaminants are not significant problem in virgin naphtha

but more prevalent in cracked and synthetic naphthas. In thede- oxygenation reactions, the CO bond is broken and thecorresponding saturated aliphatic or aromatic is formedtogether with water.

+ H 2 + H 2O

Phenol OH Benzene

Hydrogenation - Hydrogenation or olefin saturation is the addition ofhydrogen to an unsaturated hydrocarbon to produce a saturated product.Olefinic hydrocarbons are not normally present in straight run naphthas

but can be found in high concentrations in cracked naphthas. The olefinsaturation reaction is highly exothermic and proceeds relatively easilyand quickly (in top section of the catalyst bed).

CH 3-CH 2-CH=CH-CH CH 3-CH 2-CH 2-CH 2-CH 3

CH 3-CH 2-CH 2-CH 2-CH=CH 2 CH 3-CH 2-CH 2-CH 2-CH 2-CH 2-CH 3

Olefins at temperature involved in reforming process (about 500 oC) resultin coke deposits on the reforming catalyst and hence must behydrogenated to avoid coke deposition on catalyst. Olefins hydrogenationreactions are exothermic. Heat of reaction is around 30 Kcal/mol.Minimal hydrogenation of aromatics occurs, estimated at less than one

per cent. This is a consequence of high selectivity of the AXENS bimetallic catalyst.


36/71

36

Catalyst characteristics- There are two catalysts used in the Hydro treatment unit: HR-945(1 st bedof the reactor) for Olefins hydrogenation and the HR-448 (2nd bed of thereactor) for the desulphurisation and the denitrification.The main features of all the hydro treating catalysts are:

High purity alumina support having a strong resistance to attrition. High stability and selectivity towards the desirable hydro treating

reactions. Ease of regenerability.

The association of the above qualities gives the following advantages:

Efficient hydro treating. Minimal yield loss. Long catalyst life.

Catalyst mechanism: Reaction mechanisms in catalyst naphtha hydrotreating are known only for a few reactants and results are not easilygeneralised. As desulphurisation is the predominant reaction taking place,using thiophene as a model reactant, studies have shown that the firstreaction of thiophene is the C-S bond cleavage to form 1,3 butadiene,

rather than hydrogenation of the C=C bond.

e.g.

+ 2H 2 CH=CH-CH=CH 2 + H 2S

s

Thiophene Butadiene

The subsequent reaction is then:

CH=CH-CH=CH 2+2H 2 CH 3-CH 2-CH 2-CH 3

Process flow description: The following process description includes following sections:-Naphtha splitter

-NHDT (Naphtha Hydro treatment)-Reformer splitter


37/71


38/71


39/71

39

ONCE THROUGH HYDROCRACKER UNIT

OHCU comprises of three units

1. Hydro cracker2. Hydrogen Generation unit3. Nitrogen generation unit

Hydrocracker

Feed : Straight run gas oil, Vacuum gas oils, Cycle oils, Coker Gas oils,thermally cracked stocks, Solvent de asphalted residual oils, straight runnaphtha, cracked naphtha.

Product : Liquefied petroleum gas (LPG), Motor gasoline, Reformerfeeds, Aviation turbine fuel, Diesel fuels, heating oils, Solvent andthinners, Lube oil, FCC feed

Hydro cracking processes involved two types of catalyst :

1 Hydro pre treatment catalyst

2 Hydro cracking catalysts1. Hydro treating (Pre treat) Catalyst

The main objective of pretreat catalyst is to remove organic nitrogen fromthe hydro cracker feed allowing

(i) Better performance of second stage hydro cracking catalyst, and

(ii) The initiation of the sequence of hydro cracking reactions by

saturation of aromatic compoundsPre treat catalyst must have adequate activity to achieve above objectiveswithin the operating limits of the hydrogen partial pressure, temperatureand LHSV.

2. Hydro cracking Catalyst: Hydro cracking catalyst is a bi-functionalcatalyst and has a cracking function and hydrogenation dehydrogenationfunction. The former is provided by an acidic support whereas the latter is

imparted by metals. Acid sites (Crystalline zeolite, amorphous silicaalumina, mixture of crystalline zeolite and amorphous oxides) provide


40/71

40

cracking activity. Metals [Noble metal (Pd, Pt) or non- noble metalsulphides (Mo, Wo or Co, Ni)] provide hydrogenation dehydrogenationactivity. These metals catalyze the hydrogenation of feed stocks makingthem more reactive for cracking and hetero-atom removal as wellreducing the coke rate

Zeolite based hydro cracking catalysts have following advantages ofgreater acidity resulting in greater cracking activity; betterthermal/hydrothermal stability; better naphtha selectivity; betterresistance to nitrogen and sulphur compounds; low coke formingtendency, and easy regenerability.

The unit consists of the following sections:

1. Furnace2. First stage Reactor section3. Second stage Reactor section4. High pressure separator5. Fractionation Section6. Light Ends Recovery section

Effect of Operating Parameters

Various operating parameters affecting hydro cracking are

Reaction temperature, Hydrogen partial pressure, Hourly feedvelocity of the feed, Hydrogen recycle ratio

Temperature increase in temperature accelerates cracking reaction onacid sites and displaces the equilibrium of hydrogenation reactionstowards dehydrogenation. Too high temperature limits the hydro

cracking of aromatic structure .The pressure influences significantlythe equilibrium of dehydrogenation-hydrogenation reactions that takes

place on the metallic sites. The increase in pressure for a given molarratio H 2/feed corresponds to increase in the partial pressure ofhydrogen, will produce an increase the conversion of the aromaticstructures to saturated products which will improve the quality of jetfuel, diesel fuel and oil with very high viscosity index.


41/71

41

Effect of Feedstock :

A higher content of aromatic hydrocarbons requires higher pressure and higher hydrogen/feed ratio, the lowest possible

temperature and a higher hydrogen consumption of hydrogen and theseverity of the process

Effects of Feed Impurities :

Hydrogen sulphide, nitrogen compounds and aromatic molecules present in the feed affect the hydro cracking reactions. Increase innitrogen result in lower conversion. Ammonia inhibits the hydro crackingcatalyst activity, requiring higher operating temperatures. Polymeric

compounds have substantial inhibiting and poisoning effects. Polynuclear aromatics present in small amount in the residue deactivate thecatalyst.


42/71

42



43/71

43

Hydrogen generation Unit

Purpose -

To cater the refinery hydrogen demand in order to produce lowsulphur& high quality products from hydro treater and hydro cracking

Introduction: - Hydrogen generation unit was commissioned with acapacity 10,000 metric tonnes per annum of 99.99% pure hydrogen thatsubsequently increased to 150000 MTPY with a revamp in may 2003.

Feed is mixture of naphtha & FCC gasoline in ratio of 80:20 by wt .feed

impurities are unsaturated hydrocarbon sulphur& chlorine.

Chemical reaction

Basic reaction

RSH + H 2 RH + H 2S

RCl + H 2 RH+ HCl

R=R + H 2 R-R

Process description:- it consist of following main process step

1. Pre-desulphurization :- Unsaturated component as well as highamount of organic sulphur is removed from feed by catalyticconversion which is separated from naphtha by distillationR

1SS

2+ 3H

2R

1H + R

2H + 2H

2S

COS + H 2 CO + H 2S

2. Final desulphurization: - In this further catalytic hydrogenation ofthe residual organic sulphur followed by adsorption of thehydrogen sulphide on selective adsorbent bed. ZnO bed andCoMox catalyst are used for the removal of the sulphur andchlorine compound

RCl + H 2 RH + HCl


44/71

44

3. Pre- reforming:- In this the feed is reacted in presence of steam togive a mixture of methane, carbon dioxide and hydrogen over anickel bed catalyst

CnHm + n H 2O CO + (m+n) H 2

CO 2 + 4H 2 CH 4 + 2H 2OCO + H 2O CO 2 + H 2

4. Reformer :- In order to achieve high yield of hydrogen from the feedstock after pre reforming methane is converted in reformer whichoperate at high temperature

5. Shift conversion: - the process gas leaving the reforming sectioncontains carbon monoxide which is converted into CO 2 and hydrogen.

The reactor is operated at lowest possible temperature in order torecover the heat and the hydrogen generation from the feed stock.there are two temperature at which reactor are operating hightemperature shift and low temperature shiftCO + H 2O CO 2 + H 2

6. Pressure swing adsorption :- PSA technology is used to removeimpurities form reformer gas this is achieved by molecular sievewhich adsorb the contaminant and allow the hydrogen to pass

Simplified flow sheet

PREDESULPHURIZATIONVAPORIZATION

DESULPHURIZATIONPREREFORMER &

REFORMER

CONVECTION SECTION

HIGH TEMP. &

LOW TEMP.

SHIFT CONVERSION

DUAL STEAM

SYSTEM

HEAT RECOVERY

AND COOLING

PRESSURESWING

ADSORPTION


45/71

45

PROCESS FLOW DIAGRAM:

Nitrogen Generation Unit

Properties of Nitrogen :

Nitrogen is a diatomic gas which constitutes 78%of the earth atmosphere. Its atomic weight is 14

Physical Properties: Colourless, Odourless, and Tasteless

Chemical Properties: 1.Density (at 0 C and 1 atm): 1.251 g/l

2. Dew Point :: -172 C


46/71

46

3. Melting Point: -210 0C

4. Boiling Point : -195.8 0C

Properties of Oxygen:

Oxygen is a diatomic gas which constitutes about 21% ofthe earths atmosphere. It is most commonly found in its diatomic formwhich is molecular oxygen (O 2) and the triplet state known as Ozone (O 3)which is a highly active compound. Its atomic wt is 16.

Physical Properties: Colourless , Odourless, Tasteless

Chemical Properties:

1. Density (at 0 C and 1 atm) :: 1.432 g/l

2. Dew Point :: -165 C

3. Melting Point :: -218.4 0C

4. Boiling Point :: -183.0 0C

Raw materials

1- Air

Process description:

It consists of following section-Air Compression Section, RefrigerationSection, Pre-Purification Section, Cold Box, and Storage Tanks.

Air compression section:-The Air compressors receive air through AirSuction Filter and then pressurized dust and oil free air is discharged tothe Refrigeration Section. This Section consists of a 3-stage Compressors

Refrigeration Section:-Air enters the Refrigeration section DX Chillerwhere it is cooled down to a temperature of about 8 to 12 degC.Refrigerant Used-1,1,1,2 tetra fluoro ethane(R134A).Vaporized R134Areturns to the REFRIGERATION COMPRESSOR and is discharged tothe CONDENSORS where it is cooled down by cooling water . The


47/71

47

liquid R134A is then routed to vapouriser 96-E-14 after exchanging heatwith gaseous R134A and partial vaporisation through where it again coolsthe air by gaining latent heat of vaporisation from the air.

Pre-Purification Section:-AIR has been cooled to 8-12o

C at 8.7 kg/cm2,thus a part of Saturated Water is condensed. To separate this moisture airis sent to the Moisture Separator. Then the air is sent to one of the twoADSORBERS . Here moisture traces and CO2 are removed throughActivated alumina and Molecular sieve beds respectively. TheseAdsorbers adsorb impurities at a temperature of about 10 oC and areregenerated at a temperature of around 130 to 180 oC. Thus they areTemperature Swing Adsorbers .The heating for the regeneration is done

using an electric REGENERATION HEATER .After having passedthrough the adsorbers the AIR is the directed to the COLD BOX through

FILTERS

Cold box section:- The Cold Box process can be divided into 3 parts:

Cooling down and liquefaction of air-: Air enters exchanger and is cooledin counter current flow to outgoing pure N 2, waste air coming fromcolumn. The air flows out at partly liquid state and enters the lower part

of column.

Fractionating the air by distillation-: The air coming from exchangerenters the bottom of column below the bed of trays at -165.8 deg C. Thevaporizer ensures the cooling down by its Rich Liquid bath and performscondensation of the rising vapour. N2 which is in gaseous state isreceived from the column top and O2 rich liquid is received from thecolumn bottom. This liquid is further used for the exchange of Coldenergy with incoming dry air.

Productions of the Column and Vaporizer:-From the top of the Columnthe pure gaseous Nitrogen is available at about 10 oC after havingexchanged heat in counter flow to treated air in exchanger. At the top ofthe vaporizer 96-E-03 the Waste Air flows out at about 5.58 kg/sq. cm, -171.23 deg C. This Waste Air is utilized expansion turbine, which

provides the necessary refrigeration for the plant by expanding the wasteair. At the outlet of the exchanger, a part of this Waste Air at about 13 oC

and 1.2 kg/sq cm is utilized to regenerate the adsorbent beds ofAbsorbers. From the liquid receiver at the upper part of the Column a part


48/71

48

of the pure Liquid Nitrogen can be drawn off as product. If purity ofNitrogen is more than 3 ppm (vol.) oxygen, the gaseous Nitrogen

product is vented off.

Nitrogen Storage: A small portion of the reflux to Column C-01 is sent toTank T-01 A/B as liquid N 2 storage. In case of Plant Shutdown, andheader pressure down, LN (Liquid N 2) is passed to vaporizers (96-E-04A/B) which vaporizes LN to Gaseous state and supply to header. Thesetanks are vacuum insulated so as to prevent the LN from vaporizinginside the tanks.



49/71

49

LUBE OIL BLOCKLube Oil Block comprises of the following units:

Vacuum Distillation Unit-I (U-31)

Propane De-Asphalting Unit (U-32)

Furfural Extraction Unit (U-33)

Solvent Dewaxing Unit (U-34)

Lube Hydrofinishing Unit (U-35)

Bitumen Blowing Unit (U-36) [now scrapped, as it is made a partof PDA, U-36 R/D manifold]

Vis-breaking Unit (U-37)

NMP Extraction Unit (U-38)

Wax Hydrofinishing Unit (U-39)

Catalytic IsoDewaxing Unit (U-84)

The typical lube oil base stock processing circuit is shown belowfor Haldia Refinery.

Lube Processing circuit in Haldia Refinery

A t m

o s p

h e r i c

d i s

t i l l a

t i o n

V a c u u m

d i s

t i l l a

t i o n

S o

l v e n

t E

x t r a c t

i o n

S o

l v e n

t D

e - w

a x i n g o r

C a

t a l y

t i c D

e - w

a x i n g

H y d r o

f i n i s h i n

g

Propane De-Asphalting

Gas

NaphthaKeroDiesel

RCOVR DAO

VacuumDistillates

WaxyRaffinates

De-waxedoils

LubeBase Oils

150N

500N

HN

VGO

KV,Flash Point VI, CCR Pour Point Colour &Stability

150BS

Crude

Oil


50/71

50

I mpor tant Proper ties of L ube Oil

The major properties for any LOBS are as follows:1. Ki nematic Viscosi ty (kV)

It dictates the reducing power of the frictional resistance betweentwo moving parts due to the presence of the lube oil.

2. Viscosity I ndex (VI )

It defines the rate of change of kinematic viscosity with

temperature, thus governing high temperature applications viz.inside engines or compressor crankcases etc.

3. F lash Poin t

It indicates the highest application temperature at which the oilwould work without getting deteriorated. [also this is an indicatorof vaporization loss]

4. Pour Poin t

It indicates the lowest temperature at which the oil would remain inliquid state, thereby maintaining its fluidity intact, as because verylow temperatures may be encountered in land of caprice climate(e.g. at Leh etc.).

5. Colour

Lube Oil Base Stock should be water-like in appearance, the colour

that is seen in most of the marketed lube oils are due to theadditives that are added in LOBS. This colour is imparted mainlydue to unsaturated/aromatics leftover in the finished LOBS.

6. Oxidation Stabi li ty

Oxidation stability is required so as to reduce any chance of polymerization (due to contact with oxygen at some elevatedtemperature. This happens due to the presence of unsaturated.


51/71


52/71

52

(furnaces) to achieve temperature of ~400 C. This heated stream isflashed in a vacuum distillation column operating with top pressure of 70mmHg (Abs). Gas oil reflux is given at the top. Also an internal pumparound below the Light Oil draw tray helps to remove heat from thecolumn. Products like SO, LO, IO and HO are drawn from different drawnozzles from the column. Each product is stripped with stripping steam intheir respective stripper columns to remove the lighter components andthereby increases the flash pints of the products. All these products arecooled in the feed preheat exchangers followed by water or temperedwater coolers. VR is drawn from the bottom of the column and is routedto tanks after exchanging heat with the feed stream followed by steam

boilers and tempered water coolers.

Advantages:- As the boiling points reduce with decrease in pressure,

RCO need not be raised to very high temperature for further distillation.At high cracking phenomena shall get promoted leading to cokeformation in pipe lines, columns, vessels etc. Coke deposition is strictlyundesired as it leads to blockage/ clogging of pipes and restricts flowleading to unwanted unit interruptions. Vacuum distillation helps to avoidsuch occurrence.

RCO feed temp : 90 -115 deg C Preheat Temp : 285 deg C Coil Outlet Temp : 400 deg C Vac Tower Flash Zone Pr . 120 -130 mm Hg at 400 deg C Vac Tower top Pressure 70 mm Hg (Abs) Vac Tower Top Temp : 80 deg C Stripping Steam : 6.5 -10 Mt/hr Product Draw off temp : 232 , 245, 333 & 370 for

SO,LO, IO & HO Bottom Quench : 5 m3/hr


53/71


54/71

54

Advantages:-Recovery of high value DAO which can be upgraded to

high viscosity LOBS- BN (Bright Neutral) and BP (Bright Pale) grades.BN processing also gives wax in SDU which is further upgraded to high

valve Micro Crystalline Wax product in WHFU (U 39).

Operating variables:-Temperature: Rise in extraction temperature rejects

more asphalt and thus DAO quality improves but yield decreases.Propane to Feed Ratio: Increase in ratio increase DAO yield but degradesthe quality.


55/71

55

M / U P u m p s

Heater

E121A/B

H

3

2

DA

D A O M x

32

Propan

eBullets

32

ToUnit

M/UPum

ps

Steam

Steam

Airfin

Cooler

E114

A/B/C/D

E 119


56/71


57/71

57

Licensor/Technology IPIP (Romania)

Process description:-De-aerated Feed and solvent are fed to an extractor

column in a counter current direction where mass transfer takes place.Solvent is in continuous phase while the feed is in the distributed phase.The raffinate mix and extract mix are heated in their respective furnacesand flashed in their respective recovery circuit columns. The flashedvapours are condensed and collected in a solvent dryer column to removewater. The dry solvent is re-circulated back and Raffinate/ Extract

products are routed to their respective storage tanks .

Operating variables:-Temperature: Rise in extraction temperature

rejects more asphalt and thus DAO quality improves but yield decreases.Propane to Feed Ratio: Increase in ratio increase DAO yield but degradesthe quality.


58/71

58

Solvent De Waxing unit

Purpose:-

To separate the wax from the Raffinates obtained fromAromatic Extraction Units (FEU & NMPEU) to lower the pour point of

the products.

Feed Raffinates of (SO, LO, IO, HO) and DAOProducts De-waxed oils of SO, LO, IO, HO and DAO

Slack wax of SO, LO, IO, HO and DAO

Unit Capacity 290000 MT/ Annum

Methodology

Extraction and crystallization to achieve de-waxing with theaddition of SDA (for BN feed only) followed by filtration &Solvent Recovery

Solvent: MEK & Toluene in equal proportions. Toluene is oilsolvent & MEK is anti wax solvent.

Crystallization is done by chilling using Ammonia as arefrigerant. Vapor ammonia is again compressed andcondensed for recirculation

Licensor/Technology IPIP (Romania)


59/71

59

Process description:-

The feed after dilution with the solvent is chilled ina series of Double pipe exchangers (exchanges heat with filtrate)followed by Ammonia chillers. The chilled blend is then filtered inseveral Rotary Drum Filters where in the wax crystals get separated fromthe oil phase. The two phase (Lube Mix and Wax Mix phase created byfiltration is routed to their respective solvent recovery (by distillation)circuits. Recovered solvent is re-circulated into the system. De-waxed Oiland slack wax are routed to their respective storage tanks.

Advantages:-

The process helps to separate the wax components fromthe raffinates obtained from extraction units. The slack wax obtained as

by product during BN feed (DAO) is a suitable feedstock for producing avery high value product called Micro Crystalline Wax (MCW).

Operating variables:- Dilution Rate Chiller outlet temperatures Vacuum in

Rotary Filters


60/71

60

Hydro finishing unit

Purpose :-

To improve the colour and the colour stability of lube base stocks

Feed De-Waxed Oils from SDU

Products Finished LOBS

Unit Capacity 200000 MT / Annum

Process:-The process is a mild hydro treating one, using a catalyst in

presence of Hydrogen at high temperature and pressure. Removes contaminants

Sulfur Nitrogen Unsaturates

At high hydrogen partial pressure and in presence of the catalyst, Sulfur& Nitrogen in the feed get converted to Hydrogen sulfide and Ammoniarespectively. Also unsaturates get saturated resulting in stable products

Parameters name Operating range

Reactors outlet temperature 220-340 deg C

Furnace COT 210-330 deg C

Reactor dP 0.5-1.5 kg/cm2g (max. 3.5 kg/cm2g)

System pressure 55-60 kg/cm2g

Make up H 2 flow/purity 400-450 kg/h

Licensor/ Technology IFP (France)

Process description :-

Feed mixed with hydrogen is passed through preheat

exchangers followed by a furnace to reach the desired temperature level.This stream is fed to a reactor. Reactor outlet after cooling is separated


61/71

61

from the vapors. The liquid part is tripped off of lighter components in avacuum column. Product from the column bottom is sent to storage. Thevapor part after purification is re-circulated back using the recyclecompressors .

Advantages :-

Production of API Group I LOBS of various grades

Operating variables: -Reactor temperatureSystem pressureHydrogen circulation Rate

Vis-breaker unit

Purpose: -To convert the high viscosity feed stock like VR/Asphalt to low

viscosity products like VB Tar/ Furnace Oil.


62/71

62

Feed Vacuum Residue/ Asphlat/ Heavy Extracts

Products VB Tar/ FO

VB Gas oil, VB Gasolene and Fuel Gas

Unit Capacity 491000 MT/ Annum

Process :-A mild thermal cracking process, A common process wherein long

chain hydrocarbon molecules in heavy feed stocks are broken into smallmolecules having low viscosity, thereby leading to a viscosity reductionof feed stock.Feed stock is heated to relatively lower temperature (435-445 Deg C) in a furnace and partly cracked VB charge is hold in a SoakerDrum for longer residence times (25-30 min) to achieve the requiredconversion.

Process description :-The feed after passing through a series of preheat exchanges is fed

to a furnace to raise the temperature to around 440 C. This stream is passed through a soaker vessel where a residence time of around 30minutes is given. The soaker is operated at a pressure of around 10 Kg/

Cm2g. The soaker outlet is fractionated in a column where different products are separated to produce on spec Furnace Oil/ VB Tar.

Advantages:-Up gradation f low value feed stocks to valuable distillates

and VB Tar

Operating variables:-Furnace coil outlet temperature

Soaker pressureResidence timeOperating parameters:-

Furnace outlet temperature: 440 443 oCBack pressure: 10 12 kg/ cm 2 g.Residence Time: 1200-1800 Second


63/71


64/71

64


De-aerated Feed and solvent are fed to an extractor column in acounter current direction where mass transfer takes place. Solvent is in

continuous phase while the feed is in the distributed phase. The raffinatemix and extract mix are heated in their respective furnaces and flashed intheir respective recovery circuit columns. The flashed vapors arecondensed and collected in a solvent dryer column to remove water. Thedry solvent is re-circulated back and Raffinate/ Extract products arerouted to their respective storage tanks .

Operating variables:-Temperature: Rise in extraction temperature rejects more

asphalt and thus DAO quality improves but yield decreases.Propane to Feed Ratio: Increase in ratio increase DAO yield but degradesthe quality.

Wax hydro finishing unit

Purpose: -


65/71

65

To improve the colour and the colour stability of De-oiled waxobtained from SDU.

Feed De-oil wax from SDU

Products Micro Crystalline wax

Unit Capacity 15000 MT / Annum

Process

The process is a mild hydro treating one, using a catalyst in presence of Hydrogen at high temperature and pressure.

Removes contaminants Sulfur

Nitrogen Unsaturates At high hydrogen partial pressure and in presence of the catalyst,Sulfur & Nitrogen in the feed get converted to Hydrogen sulfideand Ammonia respectively. Also unsaturates get saturatedresulting in stable products

Sl. No. Parameter Operating Range1 Make up H 2 flow 400-500 kg/h2 System pressure 80-130 kg/cm g

3 F-01 COT ~300-330 deg CLicensor/Technology IFP (France)


Feed mixed with hydrogen is passed through preheatexchangers followed by a furnace to reach the desired temperature level.This stream is fed to a reactor. Reactor outlet after cooling is separatedfrom the vapours. The liquid part is tripped off of lighter components in avacuum column. Product from the column bottom is sent to storage. Thevapour part is purged to Sour fuel gas header.

Advantages:-

Production of high value Micro Crystalline Wax

Operating variables:-


66/71

66

Reactor temperature ,System pressure, Hydrogen circulation rate.

Catalytic Iso De Waxing unit

Purpose: -

Catalytic De-Waxing unit has the objective of producing superior

grade Group II LOBS.Feed Raffinates of (SO, LO, IO, HO) and DAO

Products De-waxed oils of SO, LO, IO, HO and DAO

Heavy Distillates, Light distillate and Unstabilized Naphtha

Unit Capacity 200000 MT/ Annum of De-waxed Oil


67/71

67

Methodology

Conversion of Wax component in Raffinate feed to Non- waxy componentsProcess is isomerisation of the N-Paraffins to Iso-Paraffins

N Paraffins - Waxy NatureIso- Paraffins - Non Waxy NatureFeed is purified in a Hydrotreament Reactor and then de-waxed in the De-waxing

reactor followed by a Hydro-finishing reactor.Vacuum fractionation of the De-waxed, Hydro-finished product for on grade de-waxed oil products.

Licensor/ Technology Exxon Mobile (USA)

Operating Variables

System pressureReactors TemperatureSpace velocity in the ReactorsHydrogen Circulation Rate

Parameter Operating RangeMake up H 2 flow 3500-5500 Nm /hSystem pressure 112.5 kg/cm g

R-01 WART 320-365 deg CR-02 WART 320-365 deg CR-03 WART 225-260 deg C

H2 to HC flow ratio 500-650 Nm /m liquid feed

Process Description : -

Feed after preheating is elevated to high temperature ina furnace and fed to the HDT reactor. The sweetened feed is stripped offH2S + NH3 in a stripper with pure hydrogen gas and fed to the de-waxing reactor after elevating to a designated temperature in a furnaceafter pre-heating. The de-waxing reactor outlet is then fed to a hydro-finishing reactor. Vapours after separation in a high pressure separator isrecycled back to the system. The liquid part from the stripper isfractionated in stages to remove the lighter components for achieving

desired specifications. Vapours from Hydrogen stripper are sweetened inan amine wash followed by a water wash column and the sweet gas isrecycled in to the system.

Advantages :- Production of Group II LOBS with increased yield.


68/71

68


69/71

69

OIL MOVEMENT & STORAGE BLOCK

Imported crude, brought by tankers, stored in Refinery's storage tanks

is processed successively in different units and finished petroleum

products are obtained, which are despatched for marketing by tankers,

barges, wagons, trucks, pipeline, drums, cylinders etc.

The process is a continuous one and the Oil Movement and Storage

Division (OM&S) of the production department plays an important role in

maintaining smooth, continuous operation of the Refinery.

The broad functions of OM&S are listed as follows :-

o Receipt and storage (a) Crude oil from tankers (b) Intermediate and

Finished products from process units.

o Preparation and supply of feed to various units.

o

Blending of products. & certification of products.o Despatch of certified products.o Supply of Internal fuel oil to all Furnaces.o Unloading, storing and supplying various solvents and chemicals to

units.

o Recovery of steam condensate.o Accounting of petroleum products and observing necessary

customs and excise formalities.

o Effluent Treatment.

OM&S IS SUBDIVIDED INTO FOLLOWING AREAS FOR

OPERATIONAL CONVENIENCE

Crude tanker unloading.


70/71

70

Crude tank farm including MCO Tank Farm. LPG storage area. LPG Bottling plant & Bulk Truck Loading.

El, E2, E3 tank farms . E4,E6 Tank farms. Fl, F2, F7 Tank Farms. F3 tank farm. Tank wagon loading. Tank Truck loading. 700 tank farm 750 tank farm and condensate recovery station. 800 tank farm. 850 tank f arm. 900 tank farm. 950 tank farm. Bitumen cooling unit. Bitumen drums filling station and Bulk despatch . Bitumen Emulsion Micro-crystalline Wax Palletizing unit . Solvent tank farm. Effluent treatment plant. Accounting.


71/71

Documents

Training Report of Iocl