FCC PROCESS FUNDAMENTALS & TECHNOLOGY EVOLUTION

FCC PROCESS FUNDAMENTALS &

TECHNOLOGY EVOLUTION

June 3, 2013

Debasis Bhattacharyya([email protected])

8th Summer School on Petroleum Refining & Petrochemicals 3 – 7 June, 2013

Outline

Process fundamentals

Catalytic cracking

Fluidization regimes

Position in refinery

Process flow diagram

Mode of catalyst regeneration

Heat balance

Process variables

Technology evolution

Reactor-Regenerator configuration

Hardware internals

Catalysts & Additives

Resid processing

Requirement specific developments

Summary2

Refining Processes

Refinery

Crude oil separation

Molecular rearrangement &

combination

Molecular cracking: large

to small

Contaminant removal /

product quality improvement

Cracking of Heavy Hydrocarbons

Cracking : Breaking large molecules by application of heat with or

without catalyst with or without hydrogen

Thermal Catalytic Hydro

Low cokeHigh coke

Fluid Catalytic Cracking (FCC)

Vacuum gas oil (VGO)

Hydro-treated VGO

Hydro-cracker bottom

Coker gas oil (CGO)

De-asphalted oil (DAO)

Reduced crude oil (RCO)

Vacuum residue (VR)

Dry gas

(H2, C1, C2)

LPG

(C3, C4)

Light cracked naphtha (LCN)

(C5-150oC)

Heavy cracked naphtha (HCN)

(150 - 220oC)

Light cycle oil (LCO)

(220 - 370oC)

Clarified oil (CLO) or Decant oil (DO)

……. being continued till todayConversion wt% = (Feed- LCO- CLO)*100/Feed

5

C

R

U

D

E

D

I

S

T

Gasoline

Blending

VACDIST

Gasoline

Crude

Kerosene

Jet fuel

Visbreaker /

Coker

Diesel

S

T

A

BLPG

Gas

Hydro-cracker/

Treater

HDS CCR

Reformate

HDS

HDS

BBU Bitumen

Fuel Oil

Coke

Position of FCC in Refinery

FCC

6

Flue Gas

to WHRU

Air

Products to

Fractionator

SteamRegenerator

Stripper

Reactor

Feed

Riser

Steam

Schematic of FCC

RCSV with Riser outlet temp. SCSV with reactor level

Minimum fluidization

(0.001-0.05 m/s)

Turbulent (0.7-1.1 m/s)

Bubbling

(0.05-0.30 m/s)

Fast fluidization/

Pneumatic transport

(5-20 m/s)

7

RCSV

SCSV

Fluidization Regimes

Increasing Gas Velocity

....

.

...

..

.

...

.

.

.

.

.

..

..

Fixed

bedParticulate

regime

Bubbling

regime

Slug flow

regimeTurbulent

regime

Fast

fluidizationPneumatic

conveying

P

LP

LUmf

UmbUch

.

.

.

..

.

.

.

8

Fluid Catalytic Cracking

Wet gas compressor

Feed surge drum

Pump

Feed pre-heat furnace

DDSV

Orifice chamber

CO boiler

Waste heat recovery section

Flue gas stack

FCC Internals

10

Feed injection nozzles

Riser termination device

Cyclone separator

Cyclone separator

Reactor dome quench nozzle

Stripper internals

Stripping steam

distributor

Spent catalyst

distributorRegenerator air distributor

Regenerator dome

quench nozzle

Cracking Paraffins + Olefins

Cracking LPG Olefins

Cyclization Naphthenes

Isomerization Branched Olefins H Transfer Branched Paraffins

H Transfer Paraffins

Cyclization Coke

Condensation Coke

Dehydrogenation Coke

Cracking Olefins

Dehydrogenation Cyclo-olefins Dehydrogenation Aromatics

Isomerization Naphthenes with different rings

Side chain cracking Unsubstituted aromatics + olefins

Trans alkylation Different alkyl aromatics

Dehydrogenation Polyaromatics Alkylation Coke

Condensation Dehydrogenation

Condensation

Paraffins

Olefins

Naphthenes

Aromatics

Hydrogen transfer Naphthene + Olefin Aromatic + Paraffin

Main Catalytic Cracking Reactions

11

Different Modes of FCC: Comparison

Mode LPG Gasoline Distillate

Typical product yields, wt%

Dry gas 6.5 4 2

LPG 40 18 10

Gasoline (C5-150oC) 25 45 30

TCO (150-370oC) 10 22 44

CLO ( 370oC+ ) 4 6 10

Coke 6.5 5 4

216oC - Conversion 90 81 50

12

Coke deposited on catalyst – blocks the active site – causes temporary

deactivation needs burning to regenerate before circulating to riser

Types of Coke

Coke yield = Feed coke + Catalytic coke + Strippable coke + Contaminant coke

Feed coke = 1 (feed CCR); where, 1 = f1(feed vaporization/distribution)

Catalytic coke = f2 (ROT, Cat/oil ratio, Catalyst/feed quality, Conversion level..)

Strippable coke = f3 (Stripper efficiency, Riser operation- temp.)

Contaminant coke= Coke contributed by the contaminant metals in feed

= f3 (metal level on catalyst, catalyst characteristics, operation severity, use

of metal passivator)

13

Coke deposited on catalyst – blocks the active site – cause temporary

deactivation of the catalysts

Coke on catalyst needs to be burnt to regenerate before circulating to

riser bottom

Balancing coke is the most crucial in design of FCC unit

Mode of Catalyst Regeneration

Coke burning reactions

C + 1/2O2 CO (∆H = - 2200 kcal /kg)

CO + 1/2O2 CO2 (∆H = - 5600 kcal /kg)

H2 + 1/2O2 H2O (∆H = - 28900 kcal /kg)

Mode Total

Combustion

Partial

Combustion

Coke on regenerated catalyst, wt% < 0.05 > 0.05

Effective catalyst activity Higher Lower

Regenerator temperature, oC Higher Lower

CO in flue gas, ppm < 1000 > 1000

Requirement of CO Boiler No Yes

Chances of Afterburning Lower Higher

14

FCC Heat Balance

Regenerator ReactorSpent CatalystFlue gas

Heat losses

Regeneration

Air Feed Pre-heater

Recycle

Fresh Feed

Products

Heat LossesHeat of

Coke

Combustion

Heat of

Reaction

Regenerated

Catalyst

15

Coke yield = Wcoke/Wfeed

= Wcat*(CSC-CRC) / Wfeed

= (Cat/Oil)*(Delta Coke)

Delta Coke = (Cpcat / DHcoke )*(Trg-Trc) (Trg-Trc)

Reactor heat demand per unit total feed

Heat of Combustion per unit Coke

= (Cat/Oil)*(Delta Coke)

FCC Heat Balance

Coke yield =

Delta Coke (Trg-Trc)

For a given ROT, more is the Delata coke, more will be the regenerator dense bed temperature

16

17

Variables in FCC

Independent

Feed rate

Recycle ratio

Feed preheat

Riser top temperature

Reactor pressure

Fresh catalyst activity / Selectivity

Major dependent

Regenerator temperature

Catalyst circulation rate

Regenerator air flow

Coke on regenerated catalyst

Product yields

17

Evolution of FCC Technology

1940s Fluid Catalytic Cracking Process for Gasoline

Period FCC process development

1936-1941 Fixed bed

1941-1960 Moving bed

1942-today

1942

End of 1945

1955-1970s

Post 1970s

Fluid bed

1ST commercial FCCU was

on stream at Baton Rouge

Refinery of Standard Oil of

New Jercy

33 FCCU were in operation

Dense bed reactor

Short contact riser with

pneumatic conveying -

become popular

18

Evolution of FCC Hardware Design

19

Exxon’s Model-IV FCC Unit

Flexi-cracking by ExxonMobil20

Kellogg Orthoflow FCC Converter

Evolution of FCC Hardware Design

Orthoflow Resid FCC Converter 21

UOP RFCC Unit

UOP high efficiency regenerator RFCCU

Resid FCC Units

Fast fluidized

regenerator

Two-stage regenerator

22

Two Stage Regeneration

RFCC unit by SWEC

R2R unit by Axens

23

Evolution of FCC Hardware Design

24Source: www.kbr.com

Feed Injection System

Rapid feed vaporization and

uniform mixing with catalyst Reduce non-selective cracking &

thermal reaction

Better feed nozzle design

using dispersion steam

Enhance vaporization

Avoid backmixing of hydrocarbons

Avoid thermal cracking

Reduce hydrocarbon partial pressure

Reduce coke make & improve yieldsFeed coke = 1 (feed CCR)

where, 1 = f1(feed vaporization/distribution)

25

Effect of Feed Atomization

Parameter Case-1 Case-2 Case-3

Oil droplet size, 500 100 30

Relative no. of droplets 1 125 4630

Oil droplets/catalyst particle 0.001 0.11 4

Vaporization time, milisec

at 50% vorization 220 11 4

at 90% vaporization 400 20 8

26

Reactor Riser Disengaging Devices

T-TypeDisengage

r

Down Turned

Arm

VentedRiser

Direct-ConnectedCyclones

27

Vortex Separation System

Reactor Riser Disengaging Devices

Ramshorn type or Linear

Disengaging Device (LD2)

28

Closed Cyclone Riser

Termination

Source: www.kbr.com

Regenerator Cyclone System & Orifice Chamber

Regenerator CyclonesOrifice chamber

Source: www.hason-steel.com

Regenerator Air Distributor

Flat pipe grid preferred due to uniform coverage & lower discharge velocity

Air distributors• Minimizing gas bypassing or channeling

• Mass transfer diffusion resistance

• Erosion

• Thermal expansion – mechanical reliability

• Mechanical integrity of supports

Commonly used• Pipe grid

• Air ring

Efficient air grid

• Total combustion regenerators least excess oxygen in flue gas

• Partial combustion regenerators minimum afterburning30

31

FCC Catalyst Improvement

Zeolite pores

6.5-13. 5A

Matrix pores

10-200A

Interparticle void

1 micron

Colloidal binder

clay

Zeolite: Silica-alumina

Amorphous matrix: Silica, silica-alumina, alumina

Filler clay: Silica-alumina

Other elements: Rare earth, Sodium

Catalysts Heart of FCC process undergone evolutionary changes

1942 Natural clay, Synthetic low alumina catalyst

1948 Micro-spheroidal catalyst (low alumina)

1955 High alumina synthetic catalyst

1961 D5 zeolite TCC bead catalyst

1964 Spray dried fluid Y zeolites

1980 Coke selective Re-HY catalysts

1986 Improvement in Y-zeolites (USY) – low coke selectivity,

Higher octane (low non-framework alumina)

32

FCC Catalyst Improvement

Today’s FCC catalysts

Porous spray dried micro-spherical powder

Particle size distribution of 20 -120 micron & particle density ~ 1400 kg/m3

Comprising Y zeolite in many derivatives of varying properties

Supplied under various grades of particle sizes & attrition resistance

Continuing improvement metal tolerance, coke selectivity

Year 1950 1970 1990

Zeolite content, wt% 0 10 40

Particle density, g/cc 0.9 1.0 1.4

Relative Attrition Index 20 5 1

Improvements in FCC catalysts

Zeolite based catalyst – improved yields of desired products with

given feed & hardware

ZSM-5 Additive

• Increases yields of LPG / Light olefins

• Improves Gasoline RON

Bottom Cracking Additive

• Upgrades bottom fraction of feed without proportional increase in coke make

GSR Additive

• Reduces Gasoline Sulfur content by ~ 30%

33

CO Promoter

• Enhances CO burning in regenerator dense bed

SOX Control Additive

• Reduces SOx in regenerator flue gas

Ni passivator & V- Trap

• Reduces detrimental effects of metals on product yields & catalyst health

Use of Additives

Ni More H2, Dry Gas & Coke

V &NaZeolite Destruction

S SOx Emmission, ‘S’ in Product

Basic N2 Zeolite Acidity Neutralization

Aromatics More Coke & Low conversion

High Regen temp, Low Cat/OilCon. Coke

Problems with Resid Processing in FCC

High catalyst consumption to maintain activity34

FCC Catalyst Cooler

Removal of heat

• Reduces regenerator temperature

• Retains catalyst’s activity

• Increases catalyst to oil ratios

• Better yields & enhanced profitability

External vertical shell & tube heat

exchanger

• Catalyst flows over entire cross

sectional area of tube bundle in

dense phase

• Provides variable heat sink &

produces steam upto 850 psig

35

Shifting in objective of FCC operation

•Gasoline

Alkylation& Isomerization feed

•Productquality

•Resid

Petrochemical feed stock

1942 1970 1990 1995 2010

Op

era

tin

g O

bje

cti

ve

36

Technologies Developed by IndianOil

Technology Feed Major products Challenges overcome

INDMAX Heavy feed-

VGO, RCO,

VR (part)

Light olefins, LPG,

high octane

gasoline

• Deep cracking of heavier feed

with lesser Coke & Gas

formation

• Unit heat balance

• Metal deactivation of catalyst

INDALIN Naphtha Light olefins, LPG,

gasoline

• Cracking of low molecular

weight hydrocarbon

• Unit heat balance

INDALIN

Plus

Naphtha Auto-grade LPG

(saturated) & high

octane gasoline

• Cracking of low molecular

weight hydrocarbon

• Unit heat balance

• Saturation of LPG without using

external hydrogen

Dist-Extra Heavy feed-

VGO

Diesel component

with higher cetane

• Optimization of intermediate

fraction with lower yield of

bottom fraction

Indmax Technology – Resid to Olefins

Operational features

High cat/oil ratio (15-25)

Higher riser temperature (>550oC)

High riser steam rate

Relatively lower regen temp.

Benefits

LPG 35-55 wt%

Propylene 17-25 wt% feed

High octane gasoline (95+)

Multifunctional proprietary catalyst

Higher propylene selectivity

Superior metal tolerance

Lower coke make

Indmax can handle high CCR, non-hydrotreated feed

with attractive LPG / light olefins yield

Successfully commissioned at Guwahati refinery in June’03 - Smoothest

commissioning in IOC’s FCC start-up

38

Indmax-FCC Reactor-Regenerator

Micro-Jet Feed

Injection Nozzles

Direct-Coupled

Cyclones

Reaction Riser

(Short Contact Time)

External Regenerated

Catalyst Hopper

Turbulent

Regenerator

Bed

Cyclone

Containment

Vessel (CCV)

MG

Stripper

Direct-Coupled

Cyclones

Turbulent

Regenerator Bed

Cyclone

Containment

Vessel (CCV)

MG

Stripper

39

Being worldwide licensed by Lummus Technology,

USA based on Basic Process Design data/information

& catalyst from IndianOil

INDMAX - Continual Development

Process development &

pilot plant demonstration

Improvement of

light olefins yield

Setting up 85000

BPSD unit

Yields of light olefins

with paraffinic VGO

feed (wt%): Propylene: 27

Butylenes : 15

Ethylene : 14

Scale up &

Commercialization

Collaboration with

Lummus for global

marketing & licensing

INDMAX

40IndianOil’s proven INDMAX technology can meet Refiner’s objectives of propylene maximization &

residue upgradation in cost effective manner

FCC has been the most profitable & flexible refining process for more

than seven decades because of its ability to meet changing demands

FCC technology is still undergoing significant evolution

Beyond certain feed CCR, RFCC becomes too expensive due to

high consumption of catalyst & inferior product yields

Increasing gap in propylene demand & supply drives orientation of

FCC operation towards propylene maximization

Scenario specific tailor made technology can be developed through

proper understanding of fundamentals

IndianOil’s proven INDMAX technology can meet the Refiner’s

objectives of propylene maximization & residue upgradation in an

cost effective manner

Summary

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