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Chennai Petroleum Corporation Limited A group company of Indian O il)

“HYDROCRACKER OPERATION”

Presented by

V.Vasant KumarChief Manager- Process Engineering

RESOT Centre

17 th March 2 11



TopicsTopics for discussionfor discussion

What is a Hydro-cracker?

What Does a Hydro-cracker Do?Hydro-cracker Merits &Demerits.History of Hydro-cracking.

Chemistry of Hydro-cracking.Process Configurations.



Topics for discussion (Topics for discussion ( Contd.)Contd.)

Process descriptions- General

Process VariablesEmergency handling

Modifications& operational Improvementdone in CPCL – OHCU.

Case study –CPCL –OHCU.Hydro-cracking Licensors



Process UnitsProcess Units

Unit Licensor Capacity

CDU / VDU EIL 3.0 MMTPA

Visbreaker Lummus 1.15 MMTPANetherlands

Hydrocracker Chevron Lummus 1.65 MMTPAGlobal,USA

CRU Axens, France 225,000 TPA

Hydrogen Technip Benelux 45,000 TPA(56,000)

Netherlands



Process UnitsProcess Units

Unit Licensor Capacity

LPG & UOP, USA 42,000 TPA

Kero Merox 600,000 TPA

Sulphur Recovery EIL / 180 TPDDelta Hudson, Canada

Amine Regeneration EIL 330 MT/hr

Amine Treating :a) Fuel gas treating EIL 35,000 TPAb) LPG treating EIL 60,000 TPA

Sour Water Stripper EIL 60 TPH



What is a Hydrocracker?What is a Hydrocracker?What is a Hydrocracker?

It is a catalytic process for treating and cracking ofH-C feed to lighter products under the condition of

high hydrogen partial pressure and high temperaturein the presence of a catalyst.



What does a Hydrocracker do?What does a Hydrocracker do?

Removes Metals (HDM) 100%Removes Olefins 100%

Removes Sulfur (HDS) 100%Removes Nitrogen (HDN) 100%

Saturates Aromatics (HAD) 50-95%Convert Feed to Products 40-100%H2 Consumption 170-422 Nm3/m3Operating Pressure 70-210 kg/cm2GOperating Temperature 315-430°C

Removes Metals (HDM)Removes Metals (HDM) 100%100%

Removes OlefinsRemoves Olefins 100%100%

Removes Sulfur (HDS)Removes Sulfur (HDS) 100%100%Removes Nitrogen (HDN)Removes Nitrogen (HDN) 100%100%

Saturates Aromatics (HAD)Saturates Aromatics (HAD) 5050 --95%95%Convert Feed to ProductsConvert Feed to Products 4040 --100%100%

H2 ConsumptionH2 Consumption 170170 --422 Nm3/m3422 Nm3/m3

Operating PressureOperating Pressure 7070 --210 kg/cm2G210 kg/cm2G

Operating TemperatureOperating Temperature 315315 --430430 °°CC



HYDROCRACKER MERITS &HYDROCRACKER MERITS &DEMERITSDEMERITS

Merits :i) upgrades heavier fraction of feed to superior quality products.

1. LN has RON, 78-85 - blending stock for the MS pool.2. HN is excellent feed to reformer. Yields high RON, MS.3. Jet fuel / SK – low in aromatics & has high smoke point.4. Diesel - high cetane No, low aromatics, sulfur content

5. Bottom products UCO – Good feed to FCCU and LUBEplant.ii) Environmental regulations have imposed limits on the

aromatic and sulfur content of the diesel in order to reduceemissions of carcinogens and sulfur oxides into theatmosphere.

iii) More favorable for production of middle distillates whencompared to a FCC unit.



HYDROHYDRO --CRACKER MERITS &CRACKER MERITS &

DEMERITSDEMERITSDemerits:

• High investment cost.• Frequent mechanical problems withequipments.

• High energy consumption.(H2 requirement)

NOTE: With the catalyst development, utilization ofsuitable metallurgy & experience gained,Hydro-cracking has become a very reliable

process world-wide.



History of HydroHistory of Hydro --crackingcracking

Early Hydro-cracking (liquid fuel from Coal):

Used Iron-Based CatalystsVery High Pressures (352 kg/cm 2G), 426°C

Temperature.Used by Germany in WW-II.

High Gas Make, Low Octane Naphtha, PoorQuality Diesel (High in Aromatics)



History of HydroHistory of Hydro --cracking (contd.)cracking (contd.)

First Modern Hydro-cracking1959: Chevron Demonstrates Modern High PressureProcess in Richmond Refinery-iso-cracking.

Union Oil Co – Unicracking.UOP – lomax hydro-cracking process.Employed Amorphous Silica-Alumina Catalysts.Rapid growth of hydro-cracking after development ofnew, Zeolite based hydro-cracking.

1962: Chevron Starts-Up the First Hydro-cracker inthe Then Sohio Refinery in Toledo, Ohio1966: Chevron’s Richmond Hydro-processing

Complex Starts-Up.

First Modern Hydro-cracking1959: Chevron Demonstrates Modern High PressureProcess in Richmond Refinery-iso-cracking.

Union Oil Co – Unicracking.UOP – lomax hydro-cracking process.Employed Amorphous Silica-Alumina Catalysts.Rapid growth of hydro-cracking after development ofnew, Zeolite based hydro-cracking.

1962: Chevron Starts-Up the First Hydro-cracker inthe Then Sohio Refinery in Toledo, Ohio1966: Chevron’s Richmond Hydro-processing

Complex Starts-Up.



History of HydroHistory of Hydro --cracking (contd)cracking (contd)

State-of-the-Art Hydrocracking

1. Zeolitic Catalysts.2. Lower Pressures, 70 – 200 kg/cm2G.

3. Moderate Temperatures 340 - 410°C.

State-of-the-Art Hydrocracking

1. Zeolitic Catalysts.2. Lower Pressures, 70 – 200 kg/cm2G.

3. Moderate Temperatures 340 - 410°C.



Hydrocracking LicensorsHydrocracking Licensors

Until Early 1990s, the Market (~120 HCRs) WasDivided Roughly 1/3 Each Between UOP, Unocaland Chevron.

In 1995, UOP Bought Unocal Technology, and Now Have 2/3 of the World’s HCRs.

Other Licensors (Minor Players).

– IFP (Subsidized by French Government) – MAKFina (Mainly Compete in Mild HCR) – Shell Global (Several Captive Shell Units,

Criterion Cats)

Until Early 1990s, the Market (~120 HCRs) WasDivided Roughly 1/3 Each Between UOP, Unocaland Chevron.

In 1995, UOP Bought Unocal Technology, and Now Have 2/3 of the World’s HCRs.

Other Licensors (Minor Players).

– IFP (Subsidized by French Government) – MAKFina (Mainly Compete in Mild HCR) – Shell Global (Several Captive Shell Units,

Criterion Cats)



Chemistry ofChemistry of

HydroHydro --crackingcracking



Chemistry of HydrocrackingChemistry of Hydrocracking

Typical Hydro-processing & Hydro-crackingReactions:

1. De-metallization.2. De-sulphurization.3. Denitrification.

4. Olefin Saturation.5. Aromatics Saturation

6. Hydro-Cracking7. Sulphiding8. De-methalization - Thermalcracking9. Heat Release



Desulfurization reactions convert thiols or thiophenes tostraight-chain or branched paraffins and H2S. The heat of

reaction for desulfurization is about 560 kcal/Nm3 (60 Btu/SCF)of hydrogen consumed.

R C CH

CHHC

S

+ 4H2 Catalyst CH 3 CHCH 2CH 3

Branched ParaffinThiophene

R

R CH SH

R

+ H2 Catalyst

Thiol

R CH2 RStraight-Chain

Paraffin

+ H 2S

+ H 2S

Desulphurisation ReactionDesulphurisation Reaction



RCH2 CH2 CH2 NH2 + H2 RCH2 CH2 CH3 + NH3CATALYST

AMINE PARAFFIN AMMONIA

Typical hydrotreating reactions with nitrogencompounds include hydrogenation of pyridines to formparaffins and ammonia, quinolines to form aromatics

and ammonia, and pyrroles to form paraffins andammonia. The heat of reaction of the denitrificationreactions is about 660 kcal/Nm3 (70 Btu/SCF) of

hydrogen consumed.



R-CH2CH =CH2 + H2 RCH2CH2CH3CATALYST

OLEFIN PARAFFIN

Hydrogenation of olefins is one of the most rapid of thereactions taking place. All olefins are saturated veryearly. The heat of reaction for these reactions is about

1320 kcal/Nm3 (140 Btu/SCF) of hydrogen consumed.Because the olefin content of the Hydrocracker feed issignificant and because the saturation reactions arerapid and release a large quantity of heat.

Olefins saturation



H

H

H

H H \ / R C==== C-H \\ //

C---------C / \ H H

+ 3H2 C--------C / \ C ----------C \ / C --------- C

/ \ / \ H H H H

R

H H H

H

AROMATIC

NAPHTHENE

Hydrogenated to naphthenes heat of reactions vary from about 380-750 kcal/Nm3 (40-80 Btu/SCF) of hydrogen consumed dependingon the type of aromatic being saturated. In general, higher

pressures and lower temperatures result in a greaterdegree of aromatic saturation



LARGE HC MOLECULES -------> SMALLER MOLECULES

Paraffin of paraffin of

high carbon no. Catalyst (Ni3S2) less carbon no.

CnH 2n+2 + (x-1) H 2 x C n/x H 2n/x +2 + Heat

Where x = no. of fragments ( low carbon no. Paraffin molecules),Cracked from the high carbon no. Paraffin molecule.

The heat release from the hydro-cracking reactionscontribute appreciably to the total heat requirement.

H2 +RCH 2 CH 2 CH 2 CH 3 ---------> CH 3 CH 2 CH 3 +RCH 3Catalyst



Chemistry of HydrocrackingChemistry of HydrocrackingHydro-Cracking Reactions:

Large Side Chains Easily Removed FromRingsSaturated Rings Crack Easily.

Paraffins Hard to crack.Paraffin Products Are Highly Isomerized.

Hydro-Cracking Reactions:Large Side Chains Easily Removed FromRingsSaturated Rings Crack Easily.

Paraffins Hard to crack.Paraffin Products Are Highly Isomerized.



Chemistry of HydroChemistry of Hydro --crackingcrackingHydro-Cracking Reactions (CON):

In the reactors, sulphur and nitrogen are removed from thefeedstock. In general, the carbon skeleton of the feed

molecule is not altered by heteroatom removal; however,the boiling point of the molecule decreases by 27-54 C forsulphur compounds and up to 104 C for nitrogencompounds. Alkyl aromatics also react in the reaction stageto give three types of products:

Aromatic- saturation to give a naphthene.Aromatic- dealkylation to give a paraffin and

aromatic- piece.Aromatic- condensation to give a polycyclic aromatic.

NOTE:The amounts of each type of product depend on

processing conditions (temperature, catalyst, and hydrogenpartial pressure) and feed composition .



Chemistry of HydrocrackingChemistry of HydrocrackingOther Important Reactions

Thermal Hydrocracking or “De-methylation”

– Undesirable Side Reaction Occurring at >465°C – Can Occur at Lower Temperatures With Reduced,

Unsulfided Metals – Produces Light Gases, Mainly Methane

– High H2 Consumption, Uncontrollable Heat

Release

Other Important ReactionsThermal Hydrocracking or “De-methylation”

– Undesirable Side Reaction Occurring at >465°C – Can Occur at Lower Temperatures With Reduced,

Unsulfided Metals – Produces Light Gases, Mainly Methane

– High H2 Consumption, Uncontrollable Heat

Release



Catalyst SulfidingCatalyst SulfidingFresh catalyst as well as regenerated catalyst need to besulfided so that the optimum catalyst stability and activitycan be obtained before oil feed is introduced.

The sulfiding process consists of catalyst pretreatment with asulfiding agent in the presence of hydrogen. When heatedand passed over the catalyst, the sulfiding agent breaks downinto H2S which reacts with the metal oxides on the catalyst,

thereby generating active metal sites (metal sulfides).The reactions taking place during sulfiding are as follows:

(1) Cracking of DMDS (The Sulfiding Agent)

CH 3-S-S-CH 3 + 3H 2 2CH 4 + 2H 2SThis occurs at temperatures between 218–232ºC forDMDS.

(2) Conversion of metal oxide to metal sulfide2H 2S + 3NiO + H 2

Ni 3S2 + 3H 2O



Heat Release/HHeat Release/H 22 ConsumptionConsumptionFrom HydroFrom Hydro --crackerscrackers

Reaction H2ConsumptionHeat Release,(Kcal/Nm 3 H2)

HDS 3 mols H2/mol S(17-25 Nm 3 /m 3Per 1% S Removed)

565

HDN ~5 mols H2/mol N

(5-7 Nm 3 /m 3 Per 1000 ppm N Removed) 610-705

Olefin

Saturation

~1 mol H2/C=C Bond 1200-1500

HDA ~ 3 mols H2/Ring Saturated(2-5 Nm 3 /m 3 Per 1% Rings Reduced) 660-800

Cracking 2-5Nm 3 /m 3 Per 1 LV% Conv. 470-565



Process ConfigurationsProcess Configurations



Process ConfigurationsProcess ConfigurationsProcess Configurations

Single Stage - for 100% conversion of feedinto products.Single stage - Once-Through operation – CPCL’s design configurationSingle Stage Recycle

- CPCL’s initial operation configurationTwo Stage Recycle

Single StageSingle Stage -- for 100% conversion of feedfor 100% conversion of feedinto products.into products.Single stageSingle stage -- OnceOnce --Through operationThrough operation – – CPCLCPCL ’’s design configurations design configurationSingle Stage RecycleSingle Stage Recycle

-- CPCLCPCL ’’s initial operation configurations initial operation configurationTwo Stage RecycleTwo Stage Recycle

Si l S O Th hSi lSi gl St OSt g O Th hTh gh



Features

– Low Investment – Low Hydrogen Consumption

– Very Flexible Plant, Handles a Variety ofFeeds – Can Handle High End Point, High N

Feeds – Pretreats VGO for FCC Feed

– Produces High VI Lube Base Stocks

Features

– Low Investment – Low Hydrogen Consumption – Very Flexible Plant, Handles a Variety of

Feeds – Can Handle High End Point, High N

Feeds – Pretreats VGO for FCC Feed

– Produces High VI Lube Base Stocks

Single-Stage Once-Through

(SSOT) Hydrocracking

SingleSingle --Stage OnceStage Once --ThroughThrough

(SSOT) Hydrocracking(SSOT) Hydrocracking



Single Stage (SSOT)Single Stage (SSOT)Single Stage (SSOT)

CPCL SSOT YIELDSCPCL SSOT YIELDS



CPCL SSOT YIELDSCPCL SSOT YIELDS

Yields, Wt % SOR EOR

C1& C2C3’sC4’s

Light Naphtha

0.640.671.46

3.40

1.111.002.31

3.60Heavy Naphtha 5.10 5.10Kerosene

DieselBottomsC5+,

23.69

21.7542.4396.37

23.60

20.0242.4294.75

CPCL SSOT YIELDS

Integration of Hydrocracker Unit withIntegration of Hydrocracker Unit with



g yg ythe existing FCCUthe existing FCCU

The superior quality of unconverted oil from HCU bottom (sulphur content < 50 ppmw,N2 content < 1 ppm and metals < 0.1 ppm) is routed to FCCU as feed to derive thefollowing benefits :Improved yield pattern :

Previous Feed (wt.%) Present Feed (wt.%)(Ref-II VGO) (UCO from HCU)

Gas 2.6 2.5LPG 13.0 32.0Gasoline 27.4 49.0

TCO 45.9 10.0CLO 5.2 2.0Coke 5.9 4.5

Advantages :1. Substantial increase in LPG and Gasoline yields.2. Reduction in CLO and Coke yields.3. Better quality products with very low sulphur content (MS ‘S’ <10 ppm,

RON 91 and TCO ‘S’ content <100 ppm).

4. Reduction in SO2 emission due to lower sulphur content in feed.

Single Stage Recycle (SSREC)SingleSingle Stage Recycle (SSREC)Stage Recycle (SSREC)



Features: Relative to SSOT – Can Achieve Almost Full Conversion (97%) – Moderate Investment – High Quality Products – High Hydrogen Consumption

Features: Relative to SSOT – Can Achieve Almost Full Conversion (97%) – Moderate Investment – High Quality Products – High Hydrogen Consumption

Single-Stage Recycle (SSREC)

Hydrocracking

SingleSingle --Stage Recycle (SSREC)Stage Recycle (SSREC)

HydrocrackingHydrocracking

Two Stage Recycle (TSR)Two Stage Recycle (TSR)Two Stage Recycle (TSR)



MakeMake --UpUpHydrogenHydrogen

FreshFreshFeedFeed

FirstFirst --StageStageProductProduct

RecycleRecycleGasGas

MakeMake --Up HydrogenUp HydrogenRecycleRecycle

GasGas

SecondSecond --Stage ProductStage Product

LightLightNaphthaNaphthaHeavyHeavyNaphthaNaphtha

KeroseneKerosene

DieselDiesel

ProductProductGasGas

Maximum Liquid Yield and Highest Quality Maximum Liquid Yield and Highest Quality

Two Stage Recycle (TSR)Two Stage Recycle (TSR)Two Stage Recycle (TSR)

Hydrocracking ConfigurationsHydrocracking ConfigurationsHydrocracking Configurations



Single-Stage, Once-Through-Liquid (SSOT) – Low Conversion (35-70%)

– Minimal Quality Products (UCO to FCC U as Feed) – Relatively Low InvestmentSingle-Stage Recycle (SSREC)

– High Conversion (90+%) – High Quality Products – Moderate Investment With Easy FeedsTwo-Stage Recycle (TSR) – Full Conversion – Very High Quality Products – Moderate Investment With Difficult Feeds

Single-Stage, Once-Through-Liquid (SSOT) – Low Conversion (35-70%)

– Minimal Quality Products (UCO to FCC U as Feed) – Relatively Low InvestmentSingle-Stage Recycle (SSREC)

– High Conversion (90+%) – High Quality Products – Moderate Investment With Easy Feeds

Two-Stage Recycle (TSR) – Full Conversion – Very High Quality Products

– Moderate Investment With Difficult Feeds

Hydrocracking Configurations

Summary

Hydrocracking ConfigurationsHydrocracking Configurations

SummarySummary

P d Q li iP d Q li i



Product QualitiesProduct Qualities

Single vs Two stage hydroSingle vs Two stage hydro --cracker cracker

Product Properties VGO HDT SSOT SSREC TSR

Jet Smoke Point, mm 10-15 15-20 20-25 25-30

Heavy Diesel CetaneNumber 50 50-55 60-65 65-70



Feed & productsFeed & products

Typical Feed stocksTypical Feed stocksTypical Feed stocks



Straight run gas oil.

Vacuum Gas Oil (LVGO & HVGO ).De-asphalted Oil (DAO).

FCCU cycle oil.Cocker gas oil.

Distillates.Extracts.

Straight run gas oil.

Vacuum Gas Oil (LVGO & HVGO ).De-asphalted Oil (DAO).

FCCU cycle oil.Cocker gas oil.

Distillates.Extracts.

Typical Feed stocksTypical Feed stocksTypical Feed stocks

HYDROCRACKER FEED STREAMSHYDROCRACKER FEED STREAMS --



CPCLCPCL

HVGO Stream from Ref-II and Ref-IIIDAO

– dist 95%@585°C, vis 33 – 36cst @100°C, asp < 100 ppmw

Foots Oil – CCR 0.4%wt, Asp – 40-50 ppmw, Metals*– 3 ppmw

Slack wax – CCR - <0.1% wt, Asp – 90 ppmw, Metals – 1 ppmw

Lube distillate & Lube slop-CCR – 0.6% wt, Asp – 70 ppmw, Metals – 3.5 ppmw

VB-VGO

(* Metals = Ni+V+Fe+Na)

Products from hydroProducts from hydro -crackercracker



Products from hydroProducts from hydro --cracker cracker HYDROCRACKER UNIT PRIMARY PRODUCTS:

1. Aviation Turbine Fuel/Superior Kerosene .2. Diesel3. LPG4. Light Naphtha to H2 Unit or gasoline/ LN pool.5. Heavy Naphtha to Reformer Feed Or diesel pool.6. Unconverted Oil to FCC Feed or Storage7. CLPS Off gas to Hydrogen PSA Unit/Fuel Gas8. Sponge Oil Absorber Sweet Off gas to Fuel Gas

HYDROCRACKER UNIT BY- PRODUCTS:

1. Filter Back flush to Fuel Oil/ FCC Feed2. Sour Water to Sour Water Stripper3. Spent Caustic Solution to Spent Caustic System4. Blow down from Steam Generators to Storm Water Sewer



CRACKING REACTIONS ARE PERMITTED BY ACID SITES

HYDROGENATION BY METAL SITES

ACID FUNCTION IS SUPPLIED BY CATALYSTS BASES ANDTHESE ARE AMORPHOUS SILICA,ALUMINA OR ZEOLITECATALYST BASE DEPENDS ON THE TYPE OF PRODUCTREQUIRED.

METALS SUCH AS MOLYBDENUM, TUNGSTEN, COBALT,NICKEL, PLATINUM, PALIDIUM ARE DISPERSED ON THE

CATALYST BASE.

NITROGEN IN FEED GETS IS CONVERTED TO AMMONIA

THROUGH REACTIONS AND NH3 SO FORMED PARTIALLY NEUTRALISES THE ACIDIC SITES THUS REDUCINGCAT.ACTIVITY.

CatalystCatalyst -- CPCL HydrocrackerCPCL Hydrocracker



CatalystCatalyst CPCL Hydrocracker CPCL Hydrocracker

Total Requirements for

Catalyst Type Shape

LoadedDensities,

kg/m3

Diameter,mm Reactors 207-R1, 207-R2

Demetallization

and Grading

Sphere 913 ~4.23 16,130 37.3 203

Hydrotreating 977

ICR 134SAQ Asym Quad 2.82 x 2.31 75,022 82.2 551

Hydrocracking

ICR 126 Cylinder 951 2.54 113,348 116 667

ICR 126L Cylinder 977 1.59 12,525 12.8 494

ICR 126N Cylinder 896 2.12 69,547 73.1 438

Support 432

ICR 114ZF Trilobe 2,160 ~4.23 7,075 8 50



6/12/2006 mrb G2000829 Krishna 21

CONFIDENTIALProperty of ChevronTo be Reproduced and Used only in

accordance with written permission of Chevron.

VOL

M3

VOL

%

CAT

TYPE

207 – R1, Bed 1

207 – R1, Bed 2

207 – R1, Bed 3

207 – R2, Bed 1

207 – R2, Bed 2

37.3

52.5

29.6

30.1

86.0

12.8

11.6

16.3

9.2

9.4

26.8

4.0

ICR-122 ZSB, Demet

ICR-134 SAQ, HDT

ICR-134 SAQ, HDT

ICR-126 , HCR

ICR-126, HCR

ICR-126 N, HCR73.1 22.7 ICR-126 L, HCR

Total 321.4 100.0

CPCL ACTIVE CATALYST LOADINGCPCL ACTIVE CATALYST LOADING

207-R1 Catalyst System207207 --R1 Catalyst SystemR1 Catalyst System



FunctionCatalyst

ICR122ZSB De-metallization

SupportICR 114ZF

ICR 134SAQ

Support

Hydro-treating

ICR 114ZF

ICR 134SAQ

Hydrocracking

Hydro-treating

ICR 126SupportICR 114ZF

13.1m3

82.2m3

1.6m3

46.7m3Support Balls

1.6m3

37.3m3

0 Cata yst Systey yy y

207-R2 Catalyst System207207 --R2 Catalyst SystemR2 Catalyst System



207-R2 Catalyst System207207 -R2 Catalyst SystemR2 Catalyst System

1.6m3

69.4m 3

FunctionCatalyst

ICR 126

Support

Hydrocracking

Support

Hydrocracking

ICR 114ZF

ICR 126N/126L

ICR 114ZF

1.6m3

Support Balls

Catalyst Deactivation CausedCatalyst Deactivation CausedCatalyst Deactivation Caused



Regenerable – Carbon Deposits or “Coke” Caused by Adsorbed

Condensed Polycyclic Compounds – Adsorbed Organic Nitrogen Compounds Which Tie Up

Acid Sites, Thus Lowering Cracking Activity

Nonregenerable

– Deposited Feed Metals - Ni, V, Si, Fe, As, Pb, P – Metals Tend to Deposit Near the Outer Edge of the

Catalyst and Plug the Catalyst Pores

Regenerable – Carbon Deposits or “Coke” Caused by Adsorbed

Condensed Polycyclic Compounds – Adsorbed Organic Nitrogen Compounds Which Tie Up

Acid Sites, Thus Lowering Cracking Activity

Nonregenerable

– Deposited Feed Metals - Ni, V, Si, Fe, As, Pb, P – Metals Tend to Deposit Near the Outer Edge of the

Catalyst and Plug the Catalyst Pores

By Deposits andContaminants

By Deposits andBy Deposits andContaminantsContaminants

Sulfur leaching.Sulfur leaching.



Normally when H2 is circulated at highertemperature over the sulphided catalysts the sulphurwill be converted to H2S and the metal sulphides willbe converted to metals, which will reduce the

activities. Fresh or regenerated catalyst will be inmetal oxide, during sulphiding this metal oxides willbecome metal suphides. If leaching occur the metalcan not be sulphided again and will result inreduction of active catalyst volume. In CPCL case,licenser has noted operating at higher temperaturewill effect no leaching. but in the case of hydro-

treaters there is a temperature limit above which wecan not circulate H2 with out oil.



Process descriptionProcess description



185 kg / cm2

3



VGO

feed249.2m 3 /hr.

Feed preheating

andfiltration Furnace

Product

stripper

Light endrecoverysection

Fractionator

Fuel gas (to header) 2147 nm 3 /hr.

Light Naphtha (to MS pool / HGU) 12.3 m 3 /hr.

Heavy Naphtha (to Diesel pool / CRU) 15.5 m 3 /hr.

Off-gas to PSA(for

H2 recovery)

LPG (to storage) 7.8 m 3 /hr.

Kerosene / ATF 67.2 m 3/hr. .

Diesel 59.8 m 3/hr. .

HP

gas separator LP

gas separator

Recycle gascompressor

(RGC)

Amine

treating

Recycle gas

2,10,489 nm3

/ hr.

Furnace

UCO (to FCCU) 115.6 m3/hr. .

Gas

Liquid hydrocarbon

Heavier hydrocarbons

Lighter hydrocarbons

Lighter hydrocarbons

Make-up H 2

from HGU

360 0C

Reactors172.5 Kg/cm 2

378 0C

Make-up H 2compressor

QuenchH2

Make-up H 2

68,370 Nm3

/ hr.

68,370 Nm3

/ hr.



Feed Filter SystemFeed Filter System



Feed Filter SystemFeed Filter SystemThe oil feed must be filtered to remove solids andparticulates which would otherwise lay down on the FirstReactor top bed catalyst, prematurely plugging the topbed.

- Feed Filters, which remove solids and particulatesfrom the oil feed. (more than 20micron size

particles are trapped).

The preheated, combined oil feeds stream enter the feedfilters at 168°C where most of the solids and particulatesare trapped and removed from the reactor oil feedstream.



First and Second ReactorsFirst and Second Reactors



207R207R --1 and 207R1 and 207R --22The purpose of the First and Second Reactors is to provide acontrolled environment for the hydro-cracking and hydro-treating reactions to take place.

R1 and R2, reactors and their internals is to promote thehydro-treating and hydro-cracking reactions at a controlledrate. Temperature and good flow distribution in the reactorsare the key to controlling reaction rate and achieving goodcatalyst utilization.

Hydro-treating and hydro-cracking reactions are exothermicand higher temperatures lead to higher reaction rates. Inorder to control this temperature rise and, likewise, the rateof reaction, the catalyst is separated into three beds in thefirst reactor and two beds in the second reactor.

Essential guidelines



•



Cold High Pressure SeparatorCold High Pressure Separator(CHPS)(CHPS)



(CHPS)(CHPS)Cold High Pressure Separator (CHPS), - Separates the reactor effluentinto hydrogen-rich vapor, water, and hydrocarbon liquid reactionproducts.

The CHPS hydrogen-rich vapor steam (recycle gas) is sent to the highpressure centrifugal separator to ensure no liquid entrainment.Hydrocarbons make amine foam.

The relief valve for the high pressure loop is located on the CHPS. Theset pressure of this pilot-operated relief valve is 5% greater than thenormal operating pressure of the CHPS .

The CHPS temperature is controlled by adjusting the speed of the fansoperating in the reactor effluent air cooler. Lowering separatortemperature will:

1. Increase the recycle gas purity.

2. Lower the recycle compressor horsepower requirement.3. Make separation of oil from water in the separator moredifficult.

HP HHP H 22 S Absorber S Absorber



HP H2S Absorber, 207-C4 - Scrubs H 2S from the recycle gas stream bycontact with lean amine to help maintain high H2PP.

The normal operating temperature is 55-68°C.

The high pressure absorber is designed and operated to keep hydrocarbonfrom condensing into the amine. Vapor lines are heat traced and theamine is kept 5°C hotter than the vapor.

The temperature of the lean amine must be maintained 5°C hotter than thefeed vapor temperature to prevent and condensation of the vapor oncontacting the lean amine. (This is critical in preventing foaming in theabsorber.)

A chopper valve will close on low-low flow (20%) to prevent backflow ofhigh pressure gas on loss of the lean amine charge pumps.

Recycle Gas CompressorRecycle Gas Compressor



Recycle Gas Compressor Recycle Gas Compressor Recycle Gas Compressor - Supplies thepressure to move the recycle gas through the

reactor system.To maintain H2 partial pressure.To remove the heat of reaction.To improve oil/gas distribution.To remove products from the reactors assoon as they are formed to preventsecondary cracking.



CLPS Vapor HCLPS Vapor H 22 S Absorber S Absorber



pp 22

It Scrubs H2S from the CLPS Vapor bycontact with lean amine prior to sending

the vapor to the PSA Unit for hydrogenrecovery.It is a SS clad carbon steel vessel with a

single packed bed.The normal operating temperature is

61°C and pressure is 38kg/cm2g.



Fractionation SectionFractionation Section



The purpose of the Fractionation Section is toseparate reaction section products into sourgas, unstabilized naphtha, kerosene, diesel,and fractionator bottoms.The sour gas and unstabilized naphtha are

sent to the Light Ends Recovery Section.The kerosene and jet are finished productsand are sent to storage or blending.The fractionator bottoms are sent to the FCCUnit or storage.



HSDSTRIPPER

SKSTRIPPER



Operating conditionOperating conditionF h F d R t BPOD (112% f 37 400



Fresh Feed Rate, BPOD (112% ofDesign)Fresh Feed Rate, MM MTPALHSV, 1/Hr (Note 1)Gross Conversion, Vol %Total Catalyst Life, Yr

207-R1 207-R2

Reactor Pressure, kg/cm 2 (g) SOR/EOR Inlet 172.5/176.0 167.4/167.4 Outlet 169.0/169.0 163.9/163.9

Average Hydrogen Partial Pressure,kg/cm 2(a)

145 135

Reactor Temperature, ºC SOR/EOR Inlet 378/396 378/396 Outlet 411/429 411/429 Maximum 440 440

Gas to Oil Ratio at Reactor Inlet, Nm 3/m3

Number of Reactors 1 1

5 (With Regeneration)

845

37,400

1.850.854

MAKE-UP H2 PURITY 99.5%

CHEMICAL H2 CONSUMPTION 262nm3/m3 of feedHYDROGEN BLEED nil



Process variablesProcess variables




1. FEED EFFECTS.2. HYDROGEN EFFECTS.

3. CATALYST EFFECTS.1. Reactor temperature profile.2. Catalyst Average Temperature.

4. REACTION SECTION OPERATINGEFFECTS.

5. FRACTIONATION AND LER OPERATIONEFFECTS.




-- Feed effectsFeed effectsFEED EFFECTS:1. LIQUID HOURLY SPACE VELOCITY

(FEED RATE)2. NITROGEN.3. ASPHALTENES.4. METALS

5. POLYCYCLIC AROMATICS6. SULFUR

7. CHLORIDES



Process variablesProcess variables -- LHSVLHSVLiquid Hourly Space Velocity (LHSV)

Definition: The ratio of reactor feed rate

(m3/hr) to catalyst volume(m3).

Unit is inverse hours (1/hr)

),(),(*)234.0(

3FtVolumeCatalyst ActiveBPODRateFeedOilLHSV =

Determinants

DeterminantsProcess variables- LHSVProcess variablesProcess variables -- LHSVLHSV



– Active Catalyst Volume (Design Feature) – Feed Rate

Effects of Higher LHSV – Degrades Product Properties at Same Catalyst

Average Temperature (CAT). – Increase CAT to Maintain Product

Specifications .

– Increased CAT Increases Coking . – Higher CAT Reduces Cycle Length .

LHSV Should be Optimized to Meet ProductPro erties and Catal st Life .

– Active Catalyst Volume (Design Feature) – Feed Rate

Effects of Higher LHSV – Degrades Product Properties at Same Catalyst

Average Temperature (CAT). – Increase CAT to Maintain Product

Specifications .

– Increased CAT Increases Coking . – Higher CAT Reduces Cycle Length .

LHSV Should be Optimized to Meet ProductPro erties and Catal st Life .

Effect of Feed Nitrogen ContentEffect of Feed Nitrogen ContentEffect of Feed Nitrogen Content



Typical Nitrogen Levels Are <1100 ppm Nitrogen is a Strong Poison for Acid Sites in HCR

Catalysts.It is a temporary catalyst poison.It neutralise the active site.Desorption rate is very slow. It will take several days to

desorb.Higher N2 in feed requires higher CATs to achieve adesired conversion this will result in Shorten the Cycle

Life.Higher NH3 Levels Will need higher Water Wash Rates.

Typical Nitrogen Levels Are <1100 ppm Nitrogen is a Strong Poison for Acid Sites in HCR

Catalysts.It is a temporary catalyst poison.It neutralise the active site.Desorption rate is very slow. It will take several days to

desorb.Higher N2 in feed requires higher CATs to achieve adesired conversion this will result in Shorten the Cycle

Life.Higher NH3 Levels Will need higher Water Wash Rates.

Effect of Asphaltene in FeedEffect of Asphaltene in Feed



Asphaltene content should be less than100ppm.

Defficult to crack and saturate.Polymerise on the catalyst surface as

carbonaceous deposits. Note : Asphaltene content can be reduced by

proper operation of upsteam unit.

Effect of Metals in FeedEffect of Metals in Feed



Ni, Va, Na, Ca & Mg -present in the feed. Limit is1ppm (max).Metels are too large to fit inside the catalyst pores.Deposited on the catalyst and irreversibly destroy itsactivity.

Fe – not only deactivate the catalyst through poremouth plugging and cause pressure drop across the 1 st

bed of the 1 st reactor.

Note : Metal content can be reduced by proper operationof upsteam unit.

Effect of polycyclic aromaticsEffect of polycyclic aromatics



in Feedin FeedPolycyclic aromatics (PCA) –Coke

precursors.It is a large multi-ring aromatic compounds

tend to dehydrogenate on the catalyst,ultimately forming coke.

Has a significant effect on catalyst activityand fouling rate of down stream equipment.

Effect of Sulfur & chlorides inEffect of Sulfur & chlorides inFeedFeed



Higher sulfur content would shorten the life of thereactor and other critical equipment.

- It increases the H2S content of the recycle gas,decrease H2 partial pressure and reduce the catalyst performance.

Chloride –limit is 1ppm(max). – The salt, Mgcl2 &Nacl, bulids up at the top of the 1 st

reactors.

– Reactor pressure drop will increase. Limit thefeed rate and require a shut down.

– It may cause fouling and stress corrosion cracking inthe feed/effluent exchanger.

Effect of Feed Boiling RangeFeed mixture is dependent on the crude oil used and the



poperating conditions of the upstream units. The primaryfunction of the hydrocracker is to crack the large molecules(VGO-sized) to smaller molecules (naphtha-, kerosene-,

diesel-sized).As the feed boiling range increases, the levels of nitrogen,polycyclic aromatics (PCA), asphaltenes, and metalsincrease. A higher feed nitrogen level and higher PCA levelrequire a higher CAT. High PCA, asphaltene, and metallevels increase the fouling rate of the catalyst. Therefore,increasing the feed boiling range shortens the run span by

increasing both the required CAT and the fouling rate.Catalyst poisons such as asphaltenes, metals, and nitrogenincrease exponentially with boiling point

Sources of Contaminants andTheir Effects

Sources of Contaminants andSources of Contaminants andTheir EffectsTheir Effects



Con tam inant Sou rce Effect on Iso crackingCatalyst

Ni + V High End Point Feed 1% Metals = 15 F Act iv i ty Lo

Si S il ico ne A nt i foam Pore Mou th Plug ging

Na Sodium Hydrox ideDesal t ing / Flood ing

(po or d e-sal ter op erat ion )

1% = 15 F Act iv ity Lo ss

FeS x Cor ros ion Produ c t s Pore Mouth P lugg ing

A s A rsen ic in Cru d e 1% as = 50 F Act iv ity Lo ss

P Phos ph or ic A cid in Feed 1% P = 90 F Ac t iv ity Los s

A sp h alten es Res id u u m Hig h er Fo u lin g Rate



FEED PROPERTIESFEED PROPERTIES -- CPCLCPCL --OHCUOHCU

Feed Specifications SR VGO VB VGO



CDU/VDU – Bombay

High/Persian GulfQuali ty SpecificationsDistil lation, ASTM D 1160, ºCStart 320 300

10% 380 32430% 415 37850% 440-460 40270% 490 43590% 540 473

End Point, Max. 585 500

API Gravity 20.8-34.8 20.7Specific Gravity 0.825-0.929 0.93

Asphaltenes, Wt %, Max. 0.01 0.02Iron, ppm 0 5Nitrogen, ppmw 1000 2000Sulfur, Wt % 2.8 5Kinematic Viscosity at 50ºC, cS t 46.3Kinematic Viscosity at 100ºC, cS t 9.6Kinematic Viscosity at 200ºC, cS t 0.6-1.65Kinematic Viscosity at 250ºC, cS t 0.4-1.1CCR, Wt % 0.6 1Nickel + Vanadium, ppm 1 9

Feedstock Sources VisbreakerUnit



Process VariablesProcess Variables – – HH22 EffectsEffects



– Hydrogen Partial Pressure. – Recycle gas purity – Mack-up H2 purity – Recycle gas rate (Gas/Oil Ratio)

– Catalyst Temperature. – Catalyst life.



Process variablesProcess variables -- Make up HMake up H 22 PurityPurity

M k h d i f i f h d



Make-up hydrogen consists of a mixture of hydrogenand methane. Methane is also produced in thehydrocracking reaction. The hydrogen is consumed in

the hydrocracking reactions and lost.To maintain the desired hydrogen partial pressure andmaintain the purity of the make-up hydrogen (99.5mole%H2).If the make-up hydrogen purity falls below the design

value, a bleed may be required to maintain anacceptable hydrogen partial pressure.

l b d b

H i l b i d b

Process variables:Hydrogen Partial Pressure (pH 2)

Process variables:Process variables:Hydrogen Partial Pressure (pHHydrogen Partial Pressure (pH 22 ))



H2 partial press – can be increased by – Increasing total system pressure (operate as close as the relief

valve set press located on the CHPS).

– Increasing Make-Up Hydrogen Purity. – Increasing Recycle Gas Purity (Bleed, Treating) – Recycle Gas Rate.

– Decreasing CHPS temperature.Higher PH 2 Effects – Improves Product Properties (Jet Smoke Point, Diesel

Cetane Number). – Increases Cycle Length.

H2 partial press – can be increased by – Increasing total system pressure (operate as close as the relief

valve set press located on the CHPS).

– Increasing Make-Up Hydrogen Purity. – Increasing Recycle Gas Purity (Bleed, Treating) – Recycle Gas Rate.

– Decreasing CHPS temperature.Higher PH 2 Effects – Improves Product Properties (Jet Smoke Point, Diesel

Cetane Number). – Increases Cycle Length.

MAKEMAKE--UP HYDROGEN QUALITYUP HYDROGEN QUALITY



Parameter Hydrogen SpecificationsHydrogen Purity, Mole % 99.5(Min.)

CO + CO 2, Mole 20 ppm (Max.)

Nitrogen, Mole 50 ppm (Max.)

Water, Mole 50 ppm (Max.)

Chlorine + Chlorides, Mole 1ppm (Max.)

Note: Co- more than 30ppm and reactor temp less than 200°c, thechances of nickel corbonyl formation is more. Which is highly toxic

Example: Effect of Increased Make-UpHydrogen Purity on Product Properties

d C l L th

Example: Effect of Increased MakeExample: Effect of Increased Make --UpUpHydrogen Purity on Product PropertiesHydrogen Purity on Product Properties

d C l L thd C l L th



and Cycle Lengthand Cycle Lengthand Cycle LengthSSOT Operation, System Pressure= 169 kg/cm2

2 2 2Make -Up Purity, % 85 96 99.9

Recycle Gas Purity, % 75 86.5 90

Hydrogen Partial Pressure,kg/cm 2G

125 136 140

Jet Smoke, mm 18 20 21

Diesel Cetane Number 50 53 55

Cycle Length, Months 14 24 29

Effects of High Recycle Gas rate (Gas/Oil Ratio)

Effects of High Recycle Gas rate (Gas/Oil Ratio)

Process variables : Recycle Gas Rate (Gas/OilRatio)

Process variablesProcess variables :: Recycle Gas Rate (Gas/OilRecycle Gas Rate (Gas/OilRatio)Ratio)



Effects of High Recycle Gas rate (Gas/Oil Ratio)Decreases Catalyst FoulingMaintains High Hydrogen Partial Pressure in Reactors.Providing a heat sink for high heat of reaction in thebed.Helps Distribution of Reactants Over the CatalystBed.Limits Bed Temperature Rise.Increases Catalyst ActivityMinimizes "Overcracking" of Products by carryingthem out of the reactors before they can re-crack.(Higher Liquid Yields)

Effects of High Recycle Gas rate (Gas/Oil Ratio)Decreases Catalyst FoulingMaintains High Hydrogen Partial Pressure in Reactors.Providing a heat sink for high heat of reaction in thebed.Helps Distribution of Reactants Over the CatalystBed.Limits Bed Temperature Rise.Increases Catalyst ActivityMinimizes "Overcracking" of Products by carryingthem out of the reactors before they can re-crack.(Higher Liquid Yields)

Typical Design Guideline

Typical Design Guideline

Process variables : Recycle Gas Rate(Gas/Oil Ratio)

Process variablesProcess variables :: Recycle Gas RateRecycle Gas Rate(Gas/Oil Ratio)(Gas/Oil Ratio)



Typical Design Guideline – Four to Five Times Chemical Hydrogen

Consumption Recycle Gas Rate Should Be Maximized Within Plant Mechanical Constraints.

minimum of 845 Nm3 reactor inlet gas per m3 of fresh feed.

Typical Design Guideline – Four to Five Times Chemical Hydrogen

Consumption Recycle Gas Rate Should Be Maximized Within Plant Mechanical Constraints.

minimum of 845 Nm3 reactor inlet gas per m3 of fresh feed.



1. Level Average Temperature (LAT)2. Bed Average Temperature (BAT)3 Catalyst Average Temperature (CAT)

1. Level Average Temperature (LAT)2. Bed Average Temperature (BAT)3 Catalyst Average Temperature (CAT)

Process variables ; Reactor TemperatureProfile

Process variablesProcess variables ;; Reactor TemperatureReactor TemperatureProfileProfile



3. Catalyst Average Temperature (CAT)Temperature Profile:1. The LAT is the simple arithmetic average for a set of thermocouples at one

level in a catalyst bed.2. The BAT is the simple arithmetic average of the bed inlet and outlet LATs.3. The CAT is the weighted average of the BATs.There are three types of profiles:

1. A flat temperature profile means the BATs are equal.2. An ascending profile means that each successive BAT is higher than the bed

above.3. A descending profile means that each successive BAT is lower than the bed

above. This profile is rarely used (or achievable). Note: BAT, CAT, and temperature profiles are all used to monitor reactor

performance. The CAT determines how hard the catalyst is working and the temperature profile describes how the work is distributed over the reactor.

3. Catalyst Average Temperature (CAT)Temperature Profile:1. The LAT is the simple arithmetic average for a set of thermocouples at one

level in a catalyst bed.2. The BAT is the simple arithmetic average of the bed inlet and outlet LATs.3. The CAT is the weighted average of the BATs.

There are three types of profiles:

1. A flat temperature profile means the BATs are equal.2. An ascending profile means that each successive BAT is higher than the bed

above.3. A descending profile means that each successive BAT is lower than the bed

above. This profile is rarely used (or achievable). Note: BAT, CAT, and temperature profiles are all used to monitor reactor

performance. The CAT determines how hard the catalyst is working and the temperature profile describes how the work is distributed over the reactor.



Process variables- catalysteffects

Process variablesProcess variables -- catalystcatalysteffectseffects



Catalyst Average Temperature (CAT ) – Indicates How Hard Catalyst is Working.

Reactor Temperature Profile

– Indicates How Work is Distributed Through theReactor.

Catalyst Average Temperature (CAT ) – Indicates How Hard Catalyst is Working.

Reactor Temperature Profile

– Indicates How Work is Distributed Through theReactor.



Catalyst Average TemperatureCatalyst Average Temperature



Higher Catalyst Average Temperature Allows – Higher Feed Rates at Constant Product Qualities. – Better Product Qualities at Constant Feed Rate. – More Difficult Feeds (Higher S, N) at Constant Product

Qualities and Feed Rate.

But “There is No Free Lunch” – Higher CATs Increase Coking Rate.

– Higher CATs Reduces catalyst Life due to increasedFouling Rate.

Process variablesProcess variables --catalyst lifecatalyst lifeThe table below summarizes the effects of changing each

of the process variables on catalyst life.



p y

Variable Change Effect on

CatalystLifeFeed Rate Increase Decrease

Conversion Increase DecreaseHydrogen PartialPressure

Increase Increase

Make-Up Gas Purity Increase IncreaseReactor Pressure Increase IncreaseRecycle Gas Rate Increase IncreaseRecycle Gas Purity Increase Increase

WASH WATER INJECTIONWASH WATER INJECTIONWash water is continuously injected into fin coolers to remove

ammonium salts.Alth gh i ll t b l t d f th t i



Although incolloy tubes were selected for the reactor aircooler, they may be subject to corrosion by deposition ofammonium bisulfide (NH4HS) salts formed from thecombination of NH3 and H2S in the reactor and/or ammoniumchloride (NH4Cl) salts formed by the combination of NH3 andHCl (from the chlorides in the feed).The sublimation range for ammonium bisulfide is generallyabout 66-93°C. The sublimation range for ammonium chloridebegins at higher temperatures generally about 191-204°C.Therefore, NH4Cl will begin to sublime upstream of thereactor air cooler.Reactor air cooler corrosion is minimized by limiting the

chlorides in the feed in the make-up hydrogen, by use of highalloy material, by balanced flow, and by continuous injectionof water at the air cooler inlet.

Process Variables have a significant impact on

Process Variables have a significant impact on

Summary of Process VariablesSummary of Process VariablesSummary of Process Variables



Process Variables have a significant impact onCatalyst Life, Yields, and Product Properties

Understanding Process Variable Effects andhow these are related coupled with therecognizing the constraints is critical tomaximizing Hydrocracker and RefineryProfitability

Process Variables have a significant impact onCatalyst Life, Yields, and Product Properties

Understanding Process Variable Effects andhow these are related coupled with therecognizing the constraints is critical tomaximizing Hydrocracker and RefineryProfitability



THANK YOU

5 vasnat kumar

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