Fcc

Fluid Catalytic Cracking Unit

FCC OPERATIONSFCC OPERATIONS& SALIENT DESIGN ASPECTS

17TH MARCH 2011

V.SRIKANTHSENIOR MANAGER(NHT/ISOM)

CONTENTS

• GENERAL• FCCU SCENARIO • CRACKING REACTIONS• FLUIDISATION• CATALYST• PROCESS DESCRIPTION• PROCESS VARIABLES• CRACKER EQUIPMENT

GENERAL

GENERAL

PRODUCTS OF PETROLEUM CRUDE OIL

• Gas (Methane & Ethane) Industrial fuel• LPG (Propane & Butane) Household fuel• Naphtha Industrial feed / Motor Spirit (MS)• Kerosene / ATF Household fuel / Aviation Fuel• Diesel Automobile fuel

• Vacuum Gas Oil No direct end use• Lube oil Lubricating oil• Paraffin Wax Candle, Matches, Water proof coating• Vacuum residue (Bottom) Industrial fuel, Asphalt

GENERALYield vs Price

0

100

200

300

400

500

600

700

800

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%Cum yield %wt

Price $/ton

Average Crude Price = 377 $/t

Stocks

PP

LUB

ATFMS KEROLoc HSD

LO Byp

Loc Naph

LPG

Exp HSD

Exp FO

BIT

Loc FO

SULP

BS

WWH

MWC3

Exp Naph

F&L

Base Case GRM = 4.75 $/bbl

CRU Feed

FCC Feed

HCU Feed

VBU Feed

PDU Feed

GENERAL • PRIMARY PROCESSING UNIT• SECONDARY PROCESSING UNIT• Secondary units are installed to:

• Upgrade lower grade products • Increase value added products• Maximise production of products in demand• Production of specialty products• Minimise production of undesired products• To meet Product / Environmental specifications

GENERAL

MEANS OF VALUE ADDITION

• Thermal Cracking High value light products• Catalytic Cracking - do -• Hydro Cracking - do -

• Extraction / Filtration Lube base oil / Wax• Iso-Dewaxing Lube base oil

CATALYTIC CRACKING

• Cracking VGO into low molecular weight products of high value, by application of heat and in the presence of catalyst

• Good selectivity – for producing desired products• Good quality products (Mainly mono-olefins)• Specialty products (Propylene, Butylenes)• High initial investment• Low fuel and loss

GENERAL

WHY FCCU? • Benefits of FCCU:

• Converts heavy ends into desired lighter products • Reaction involves regrouping of molecules to

provide the quality product• Flexibility in product pattern• Production of lower molecular weight special

products like Propylene, Butylenes• Reduces the Sulphur content in liquid streams by

converting into H2S • Minimise production of undesired products

FLEXIBILITY IN FCCFLEXIBILITY IN FCC

Easy Catalyst / Additive Loading & WithdrawalNo Hot SpotAutomatic Balancing of Heat / PressureFeed Quality VariationsLow pressure , Moderate temp.

FCC is Flexible and Thus Growing

Flexibility of Operating FCC Unit

Optional (Heavy

Naphtha)

Optional (HDT LCO)

1.4 (HCO)Recycle, CFR

> BaseBase< BaseCatalyst/ Oil Ratio

> BaseBase < BaseResidence Time

538 – 560527 – 538449 – 510Reactor Temp. °C

Light Olefin Mode

Gasoline Mode

Middle Dist. Mode

Operating Conditions

Flexibility of Operating FCC Unit

7.07.29.2HCO, LV%

10.113.937.5LCO, LV%

55.260.043.4C5+ gasoline, LV %

20.515.49.8C4, LV%

16.110.76.9C3, LV%

4.73.22.6C2, wt.%

1.01.00.7H2S, wt.%

Light Olefin Mode

Gasoline Mode

Middle Dist. Mode

Product Yield

FCC BALANCES

Mass BalanceHeat BalanceCoke BalancePressure Balance

FCC is floating on balances

FCCU SCENARIO

• 400 FCC Units in World

• Major Secondary Process since 1942

• Major source of high value lighter hydrocarbon

• Complex, Interlinked but Flexible

• Flexible operation modes: LPG, MS & Diesel

• Continuous developments in Design

• Development of Catalyst & Additives

FCC is Workhorse of Refinery

FLUIDISED CATALYTIC CRAKING

FCC/RFCC UNITS IN INDIAS.

NOREFINERY CAPACITY

MMTPALICENSOR YEAR OF

COMMISSIONING

1 HPCL(BOMBAY) 0.40 ESSO 1954

2 BPCL( BOMBAY) 1.20(0.60) SHELL(MODEL IV) 1995(1955)

3 HPCL(VISAKH) 0.95(0.40) EXXON(ESSO) 2000(1957)

4 IOCL(GUJARAT) 1.4 UOP 1982

5 IOCL(MATHURA) 1.00 UOP 1983

6 CPCL (MADRAS) 0.78(0.60) UOP 2004(1985)

7 BPCL(BOMBAY) 0.85 SWEC(UOP) 2002(1985)

8 KRL(COCHIN) 1.75(1.00) UOP 2005(1985)

9 HPCL(VISAKH) 0.60 UOP 1985

10 IOCL(PANIPAT) 0.70 S&W 1997

11 Reliance (Jamnagar) 8.0 UOP 1998

13 IOCL(BR) – RFCC 1.4 S&W 2002

12 IOCL(HR) – RFCC 1.0 S&W 2001

BLOCK FLOW DIAGRAM OF MODERN REFINERY

CRACKING REACTIONS

Process Variables 19

Principal Reaction Paths

• Thermal Cracking

• Catalytic Cracking– Primary Reactions– Secondary Reactions


Primary Reactions

• Paraffin Smaller paraffin + olefin

• Alkyl naphthene Naphthene + olefin

• Alkyl aromatic Aromatic + olefin

• Multi-ring naphthene Alkylated naphthenewith fewer rings


Secondary Reactions

• Olefin + paraffin Paraffin + olefin

• Olefin + naphthene Paraffin + aromatic

• Olefin + olefin Paraffin + diolefin(or coke)

• Olefin + olefin Paraffin + aromatic

FLUIDISATION

FLUIDIZATION REGIMESIN FCC

Name FCC Section Gas VelocityM/Sec

Bed Density,KG/M3

Packed Bed -- < 0.05 700 - 850

Min Fluidization Standpipe .01 - .05 700 - 800

Bubbling bed Stripper .05 - .30 600 - 750

Dense Bed Regenerator .30 - .70 400 - 600

Turbulent Bed -- .70 - 1.1 300 - 500

Fast Fluid Bed Combustor 1.1 - 3.0 100 - 300Pneumatic Flow Riser 2.0 - 20.0 30 - 100

FLUIDIZATION REGIME IN FCCU

Air

Riser

Stripper

LC

TC

V=0.3-0.7V=2-20

V=0.01-0.05

V=0.05-0.30

ρ= 400-600ρ= 700-800

ρ= 30-100

ρ=700-800

CATALYST

FCC CATALYST

MATRIX

ZEOLITERe-EARTHS

CLAY

PERFORMANCE FEATURES OF FCC CATALSYTS

Zeolite type and level of rare earth

Particle size Distribution, density

Density, Attrition resistance

Zeolite type, matrix type, traps

Zeolite type matrix type and amount

Activity and stability

Fluidization

Unitretention

Metal tolerance

Selectivity

FCC CATALYST ADDITIVES

• Olefin maximisation additives

• Octane enhancement additives

• Bottom Cracking Additives (BCA)

• DeSOx additives

• Metal traps

• Gasolene Sulphur Reduction (GSR) additives

PROCESS DESCRIPTION

UOP Side by Side Fluid Catalytic Cracking Unit Flue

GasFlue Gas

Slide Valve

Regenerator

Spent CatalystSlide Valve

Regenerated Catalyst

Slide Valve

Air

Raw Oil

Stripping Steam

Reactor

Products to Main Column

Process Flow and Control 32

Regenerated Catalyst Slide

Valve Control

ReactorTIC

High Temperature Closes Slide Valve

Low Differential Pressure Signal Closes Slide Valve

PDI

Low Signal Selector

PDIC

PDTPI

PI

(readable from slide valve)

Regenerated Catalystfrom Upper Regenerator

RegeneratedSlide Valve

Handwheel Actuator

Selector Switch

FCDA

ZIDG

<


Spent CatalystSlide Valve

ControlLow Level

Signal ClosesSlide Valve

PDIC

PI

Reactor

Low DifferentialPressure Signal

Closes Slide Valve

LIC

Low Signal Selector

PI

PDT

ZIPDILI

Readable from Slide Valve

Actuator Selector Switch

DG(LAHL)

LT

Spent Catalyst to Regenerator

>

Actuator

DA

DG

FC

DG

LICLT

DTDI

DG

DG

DG

DG


Conventional FCC Flue Gas System(without Power Recovery)

Flue GasSlide Valves

OrificeChamber

CO Boiler ElectrostaticPrecipitator

Flue Gas

Air

Steam

Water

PIC PDIC

>HSS

Air

Signal fromReactor

Pressure Tap

FCC-PC002


Main Column Bottoms

Circulation

Raw Oil

MCBProduct

BFW

SteamReactorProductVapor

∑

LIC

FI

FIC

CW

MCBQuench

Disc and DonutMinimum Flow

Raw Oil

LIC

DebutanizerReboiler

HCN StripperReboiler

FIC FIC

FIC

FIC

FIC

Torch OilPump Flushing Oil

FCC-PC401

FIC

PROCESS VARIABLES


Process Variable Effects

Increased CombinedFeed TemperatureIncreased RecycleRateIncreased ReactorTemperatureIncreased ReactorPressureIncreasedRegenerator PressureIncreased CatalystCirculation Rate atConstant ReactorTemperature(Increased CatCooler Duty)

Con

vers

ion

Gas

Yie

ld

LPG

Yie

ld

Oct

ane

Ole

fin C

onte

nt

Aro

mat

ic C

onte

nt

LC

O A

rom

atic

C

onte

nt

Cok

e Y

ield

Reg

ener

ator

Tem

p

Cat

alys

t/Oil

Cat

alys

t Ent

rain

men

t

Cyc

lone

Eff

icie

ncy

Req

’dSt

ripp

ing

Stea

m R

ate

Affected Variable

Adjusted Variable

Gasoline

Change in Affected Variable: –increases; – decreases

CRACKER EQUIPMENT

HARDWARE SUBSYSTEMS FOR FCCHARDWARE SUBSYSTEMS FOR FCC

Feed distributorRiser termination deviceStripper with efficient internalsCatalyst & air distributors in

regeneratorCatalyst coolerCyclonesFlue gas scrubber

HARDWARES PLAY MAJOR ROLE IN FCC

Equipment 40

Feed Distributor Historical Development

• Bayonet• Showerhead• Premix• Lift Gas• Optimix

Equipment 41

Reactor Riser Feed DistributorJet Nozzle Type

FCC/DS-R00-98

AbrasionResistant

Lining AbrasionResistant

Lining

Drain andVacuum

Connection

Equipment 42

Elevated Optimix Feed Distributor

Equipment 43

Optimix Feed DistributorWork Point

High DensityRefractory Lining

Welding NeckFlange

SteamConnection

FeedConnection

Ceramic FiberBlanket Insulation

Reactor RiserFeed Distributor

AbrasionResistant

Lining

Equipment 44

Reactor Riser Disengager Designs

• Down-Turned Arms• Vented Riser• Direct-Connected Cyclones• Suspended Catalyst Separation• Vortex Disengager System and

Vortex Separation System

Equipment 45

Reactor Riser Disengaging Devices

T-TypeDisengager

Down TurnedArm

VentedRiser

Direct-ConnectedCyclones

Equipment 46

Modern Reactor Riser Disengaging Devices

Vortex Disengager Stripper Vortex Separation System

Equipment 47

Reactor WYE Section• Hot Wall vs. Cold Wall• Cold Wall Advantages

– Less Thermal Expansion– No High Temperature Metallurgy– Metal Temperature Out of Creep

Range– No Stress Relief– Increased Operating Life

Equipment 48

Hot Wall “WYE”

RegeneratedCatalyst

ChargeBlast Steam

External Insulation

3/4” AbrasionResistant Lining

304H SS

Riser

Equipment 49

Cold Wall“WYE”

RegeneratedCatalyst

Blast SteamCharge

5” RefractoryCement Lining

Riser

Carbon Steel

Equipment 50

Catalyst Stripper

StrippingSteam

StrippingSteam

Fluffing Steam

AbrasionResistant Lining

Riser

Stripper Shell

Insulation

FCC-E005

Bubbling Bed Regenerator

T

REGENERATOR PLENUMCYCLONE SUPPORTS

REFRACTORYLINING

REFRACTORYLINING

EXTERNALLINING

SPENT CATALYSTDEFLECTOR

AIR DISTRIBUTOR

SECOND STAGECYCLONES

FIRST STAGECYCLONES

THERMOCOUPLES(1each cyclone)

TRICKLEVALVES

SPENT CATALYSTSTANDPIPE

TI’s

LEVEL ANDPRESSURE TAPS

MANWAYS

CATALYSTWITHDRAWAL

OPEN PRIMARYCYCLONE DIPLEG

TERMINATIONSLEVEL AND DENSITYPRESSURE TAPS

MANWAY

TORCH OIL

REGENERATEDCATALYSTSTANDPIPE

FCC-E003

Equipment 52

Pipe Air Grid

Equipment 53

Plan of Air Grid

PLAN(Total Number of Arm Jets Required: 1024)

= Open Jets: 850= Plugged Jets: 174

Equipment 54

Jet Detail

FCC/DS-R00-65

Equipment 55

Cyclone-Catalyst Fines Collector

Catalyst-LadenGas Inlet

Catalyst-FreeGas OutletGas Out

Catalyst-LadenGas Inlet

DisengagingHopperCatalystOutlet

Dip Pipe

Stream Pattern--Lower Portion

Stream Pattern--Upper Portion(Principally Finer Particles)

Equipment 56

Regenerator Cyclones

• First Stage– Inlet Velocity Shall Not Exceed 65 ft/sec (19.8 m/sec)– Outlet Velocity Shall Not Exceed 80 ft/sec (24.4 m/sec)– Ratio of Barrel Area to Inlet Area Shall be 3.7 Minimum

Equipment 57

Regenerator Cyclones (continued)

• Second Stage– Inlet Velocity Shall Not Exceed 75 ft/sec (22.9 m/sec)– Outlet Velocity Shall Not Exceed 120 ft/sec (39.6 m/sec)– Ratio of Barrel Area to Inlet Area Shall be 4.3 Minimum– Minimum Barrel Diameter is Equal to First Stage Barrel

Diameter

Equipment 58

Regenerator Cyclones (continued)

• Both Stages– Ratio of Cyclone Length to Barrel Diameter

Shall be 5.0 Minimum– Projected Apex of Main Cone Shall be a

Minimum Distance of 0.3 Times Barrel Diameter Above the Outlet of the Dust Hopper

Equipment 59

Cyclone Dipleg Termination

• Trickle Valve• Counterweighted Flapper

Valve• Submerged

Equipment 60

Trickle Valve

Hinge

Flapper Plate

Stop

3-5º From Vertical

Equipment 61

Weighted Flapper Valve

Equipment 62

UOP Plenum Chamber Designs

FCC/DS-R00-104

ExternalPlenum

InternalPlenum

ExternalManifold

Equipment 63

Orifice ChamberFlow

Internal Manways

Carbon Steel Shell

304H Internals

RefractoryHexmesh

Equipment 64

Orifice Chamber

• Used When Regenerator Pressure is Controlled by Flue Gas Slide Valve

• Reduces Pressure Drop Across the Slide Valve

• Grid Hole Erosion

Equipment 65

Grid Section of Orifice ChamberGrid Holes

Rings

Plan of GridCL Grid

3/4” AbrasionResistant LiningR

ing

#1R

ing

#2R

ing

#3R

ing

#4

1”

Grid Section

CL Grid

Equipment 66

Orifice Chamber GridsFirst Grid: Last Grid:

Equipment 67

Electrostatic Precipitator

Equipment 68

ESP Fines Collection Equipment

Fcc

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