fcc catalyst design: morphology, physiology, reaction chemistry and manufacturing

91
FCC Catalyst Design Morphology, Physiology, Reaction Chemistry and Manufacturing By: Gerard B. Hawkins Managing Director, CEO

Upload: gerard-b-hawkins

Post on 12-Jul-2015

755 views

Category:

Technology


1 download

TRANSCRIPT

Page 1: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

FCC Catalyst Design Morphology, Physiology, Reaction

Chemistry and Manufacturing

By:

Gerard B. Hawkins Managing Director, CEO

Page 2: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Introduction

FCC Catalyst Components - the Zeolite - the Matrix - Additives ( ZSM-5, other )

Catalyst Manufacturing

Reaction Chemistry - b scission (cracking) - hydrogen transfer - heat balance considerations

Selecting the Right Combination

Page 3: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

FCC: POSITION IN REFINERY

In the FCC unit high mol. wt. feeds

(VGO / Residue) are converted to lighter, more valuable, products

C3=, C4='s for cat. polym. C3= for dimersol / petrochem. C3's, C4's for LPG

C3=, C4='s, i-C4 for alkylation i-C4= for MTBE

Fuel Gas H2, C1, C2, C2=

Gasoline C5 - 221°C

Kerosene 150 - 250°C

Cat. Heating Oil

Diesel 200 - 350°C

FCC UNIT

Crude Atmospheric Column

Straight Run Products

Atmospheric Residue Vac. Gas Oil

Vacuum Residue

Vacuum Column

Residue Hydrotreater

HT Resid

www.gbhenterprises.com

Page 4: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

FCC Unit Operating Conditions : Typical Example

DISENGAGER

RISER REGENERATOR

190°C

735°C

720°C

Feed

Stripping steam

Produc ts

Regenerator flue gas

Regenerator Air

530°C

510°C

250°C

www.gbhenterprises.com

Page 5: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Catalyst Physical Properties

RETENTION / LOSSES - Attrition Resistance

FLUIDIZATION - Particle Size Distribution - Average Bulk Density

HEAT TRANSPORT - Specific Heat Capacity

www.gbhenterprises.com

Page 6: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

FCC Catalyst Components

Page 7: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

FCC Catalyst Components

70 µm (avg.)

7 µm

Pseudo crystalline Matrix Aluminas

Pores

Clay

Binder Zeolite Y

www.gbhenterprises.com

Page 8: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

FCC Catalyst Components

Primary catalytic component for selective cracking Can be substantially modified to alter its activity,

selectivity and effect on product quality Generally rare-earth exchanged or ultrastable Y

zeolites More than 10,000 times more active than amorphous

catalysts used before the introduction of zeolite Y

Zeolite

www.gbhenterprises.com

Page 9: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Role of the FCC Catalyst Matrix

Forms the continuum that holds together the zeolite crystals

Acid sites on active matrix component catalyze cracking of feed molecules too large to enter zeolite pores

Matrix porosity facilitates diffusion of feed molecules to zeolite

Metals traps (e.g. for Vanadium or Nickel) may be incorporated in the matrix

Matrix

www.gbhenterprises.com

Page 10: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

The Zeolite

Page 11: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Structure of Zeolite Y

Sodalite cage (β-cage)

Supercage (α-cage)

www.gbhenterprises.com

Page 12: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

(Mn+)z/n {(SiO2)y (AlO2)-z} framework

Zeolites are crystalline microporous, alumino silicates

Framework alumina (AlO2)- units are associated with Acidic Active Sites

Cations within microporous cages and channels (Mn+ = H+, La3+, Ce3+, Ce4+)

Hydrocarbon conversion catalyzed at acid sites within microporous channels

Acid Site Activity and Acid Site Density determine the Activity and Selectivity of the zeolite

Zeolite Structure and Properties

www.gbhenterprises.com

Page 13: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Zeolite Acidity Brönsted acid

site

Al

Lewis acid site

O O

O

Al Si Si

O O

H

Proton (H) donor

Trivalent Al - hydride ion abstractor

www.gbhenterprises.com

Page 14: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Brönsted Acid Site

O-

O O

O

H+ O

O O

Si Al

www.gbhenterprises.com

Page 15: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Routes for Zeolite Y Stabilization

HREY

RE ion-exchange calcine NH4

+ ion-exchange

NaY REY CREY NH4CRE

USY

NH4

+ ion-exchange ultrastabilize RE3+ ion-exchange

NaY NH4Y USY REUSY

www.gbhenterprises.com

Page 16: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Ion Exchange to Generate Acid Sites (H+)

Na+-Z- + NH4+ Na+ + NH4

+-Z- NH4

+-Z- H+-Z- + NH3 ↑

calcine

3Na+-Z- + RE(H2O)63+ 3Na+ + RE(H2O)6

3+-[Z]3-

RE(H2O)63+-[Z]3- RE(H2O)5(OH)2+ -H+-[Z]3-

hydrolysis

Ammonium Exchange

Rare Earth Exchange

www.gbhenterprises.com

Page 17: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Reaction Mechanism for Hydrothermal Dealumination and Stabilization of Y Zeolites

Framework Dealumination

Framework Stabilization

Al O Si O Si

O

Si

O

Si

O Si O Si

O

Si

O

Si

H H H H

+H2O

(Steam) +Al(OH)3

O Si O Si

O

Si

O

Si

H H H H

Hydroxyl Nest

(defect site)

Si O Si O Si

O

Si

O

Si

+SiO2

(Steam)

Hydroxyl Nest

(defect site)

www.gbhenterprises.com

Page 18: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Unit-Cell Size and Si/Al ratio

Numerous relationships given in the literature

Breck and Flanigen relationship widely used

NAl / ucs = 115.2 [ ao - 24.191 ]

and: NSi / ucs = 192 - NAl / ucs

thus: Si / Alframework = NSi / NAl

www.gbhenterprises.com

Page 19: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Control of the equilibrium UCS

UCS (Å)

As-synthesized NaY 24.64 (54 Al / uc) Ultra stabilized Y 24.54 (40 Al / uc) Steam deactivated USY 24.21-24.30*(2-13 Al /uc)

*Depends on rare-earth level - (the higher the RE, the higher the UCS)

www.gbhenterprises.com

Page 20: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

RE level vs UCS (Å)

0 10 20 30 40 50 60 70 80 90

100

24.21 24.26 24.31 24.36 24.41

UCS (Å)

RE

leve

l, %

www.gbhenterprises.com

Page 21: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Zeolite Active Site Distribution

Equilibrium US-Y Zeolite unit cell size 24.25 Å Framework Si/Al = 27 7 Al atoms / unit cell

Equilibrium CREY Zeolite unit cell size 24.38 Å Framework Si/Al = 7.8 22 Al atoms / unit cell

www.gbhenterprises.com

Page 22: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Dealumination Effect of Si / Al ratio on Zeolite

Properties

High Al Low Al

zeolite unit cell size thermal stability

hydrothermal stability

intrinsic cracking activity hydrogen transfer activity

low high high

low low

high low low

high high

www.gbhenterprises.com

Page 23: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Major Effects of Equilibrium Unit Cell Size

Increasing Unit Cell Size : Increases Active Site Density Decreases Active Site Strength

Hence, Increased Hydrogen Transfer vs. Cracking :

Increased Gasoline Selectivity Lower Gasoline Octane Numbers (RONc and MONc)

Decreased LPG (C3 and C4) Selectivity Lower LPG Olefinicity

www.gbhenterprises.com

Page 24: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Octane Response vs. Zeolite Unit-Cell Size

Gasoline

MON

RON

0

1

2

3

0

1

2

24.24 24.28 24.32 24.36 24.40

Zeolite Unit Cell Size, Å

Del

ta R

ON

, Del

ta M

ON

D

elta Gasoline Yield, W

t%FF

Increasing rare earth

www.gbhenterprises.com

Page 25: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Relative Coke Selectivity of Zeolite Types

Equilibrium Unit Cell Size

Rel

ativ

e C

oke

Sele

ctiv

ity

REUSY

CREY unit cell size range for minimum coke 24.28 - 24.34 Å

USY

CSSN CSX

www.gbhenterprises.com

Page 26: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

The Matrix

Page 27: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Selective Active Matrices Catalytically active surface

Less selective in cracking than zeolite

Variable acid site strength and pore structure

Helps crack the bottoms to provide ‘feed’ for the zeolite component

Important for metals tolerance

www.gbhenterprises.com

Page 28: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Matrix Design Considerations

Crack bottoms with minimum coke and gas penalty Provide resistance to Nickel, Vanadium and Nitrogen Controlled porosity eliminates heavy feed diffusion limitations

The appropriate Matrix type depends upon feed characteristics (e.g. aromaticity, Concarbon, metals, nitrogen, etc.)

Optimize Zeolite / Matrix ratio for low coke and gas as well as low SA/K number

Matrix Requirements

www.gbhenterprises.com

Page 29: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Example Morphologies

Tuneable Matrix Alumina (TMA)

www.gbhenterprises.com

Page 30: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Matrix Technology

Matrix System Type 1 Type 2 Type 3

Bottoms Cracking

+++

+

++

Coke/Gas Selectivity

+

+++

++

Vanadium Tolerance

+++

+

++

Nickel Tolerance

+

+++

++

Optimal matrix system is selected depending on the main operating objectives / constraints as below

www.gbhenterprises.com

Page 31: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

d (P

ore

Volu

me)

/ d

log

(Por

e D

iam

eter

)

0

0.1

0.2

0.3

0.4

0.5

0.6

10 100 1,000 10,000

Catalyst A (steamed) REUSY High Matrix Activity

Catalyst B (steamed) REUSY Moderate Matrix Activity

Pore Diameter, (Å) www.gbhenterprises.com

Page 32: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Ni Ni

Ni

Ni

Ni

Ni

Ni Ni

Ni

Ni

Ni Ni Ni

Ni Ni

Highly Dispersed - Poor Ni Tolerance Good Ni Support High Ni dehydrogenation activity

Nickel Tolerance - Matrix Consideration

Ni Ni Ni Ni Ni

Ni

Ni Ni Ni Ni

Nickel Agglomeration Chemical Reaction Poor Ni Support Low Ni dehydrogenation activity Å 100

Ni Al

Al

Al

Al

Al

NiAl2O4

Solid State Diffusion Chemical Reaction Strong Metal-Support Interaction Low Ni dehydrogenation activity

Ni trapping matrix

solid state

diffusion

www.gbhenterprises.com

Page 33: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

SA/K Number

Lower SA/K number:

improves catalyst strip ability (decreasing occluded coke)

provides a poorer support for contaminant metals (decreasing contaminant coke)

Both the above contribute to improved coke and gas selectivity

AVOID EXCESS CATALYST SURFACE AREA - ONLY NEED SURFACE AREA THAT CONTRIBUTES TO PRODUCING DESIRED

CONVERSION PRODUCTS

SA/K number = Total ECat Surface Area Kinetic Conversion

= Total ECat Surface Area MAT Conv. / (100 - MAT Conv.)

www.gbhenterprises.com

Page 34: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Major Effects of Increased Z/M Ratio

Increasing Z/M : Increases Selective Zeolite Cracking Lower Coke and Fuel Gas (C2-) Yields Increased Gasoline Selectivity

But, Lower LCO Selectivity Increased Bottoms Selectivity

www.gbhenterprises.com

Page 35: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Effect of Zeolite/Matrix Ratio on Product Selectivity's

MAT Reaction Conditions: 60 wt% conversion Feed: 0.919 g/ml, 11.5 Watson K

Zeolite / Matrix Surface Area Ratio of Steamed Catalyst

Amorphous Cracking

Zeolite Cracking

LCO

, wt%

C

oke,

wt%

0 2 4

2.0

4.0

24.0

25.0

26.0

38.0

40.0

42.0

44.0 G

asol

ine,

wt%

Dry

Gas

, wt%

H

CO

, wt%

C

3 +

C4,

wt%

1.0

1.4

1.8

16.0

15.0

14.0

13.0

15.0

14.0

13.0

12.0

www.gbhenterprises.com

Page 36: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

FCC Additives

Page 37: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

ZSM-5 Additives

Page 38: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

ZSM-5 Additive Particle

MICROSTRUCTURE MESOSTRUCTURE

MACROSTRUCTURE

75 µm

Zeolite ZSM-5

7 µm

Binder

Filler

www.gbhenterprises.com

Page 39: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

ZSM-5 framework structure ZSM-5 pore structure

Zeolite ZSM-5 Crystal Structure

www.gbhenterprises.com

Page 40: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

ZSM-5 Shape Selectivity

slow

Products

Products

Reactants

fast

Non-reactants

www.gbhenterprises.com

Page 41: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Selective Conversion of Low Octane Species

The relative cracking for various hydrocarbons are:

Rel. rate Rel. octane Hydrocarbon Type

Straight chain paraffins & olefins

Moderately branched paraffins & olefins

Highly branched paraffins & olefins

Naphthenes

Aromatic side-chains

Fast

Moderate

Slow

Slow

Slow

Low

Moderate

High

Low

High

www.gbhenterprises.com

Page 42: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

ZSM-5 Additive Technology Cracking Mechanism

Hydrogen Transfer

Low active site density of ZSM-5 (relative to H-Y) results in low hydrogen transfer activity thus products have a high degree of olefinicity

Isomerization

Isomerization of lower to higher branching is favored due to the relative stabilities of carbo-cation intermediates (tertiary > secondary > primary)

www.gbhenterprises.com

Page 43: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Commercial Data: Unit Response to 3 wt% Additive Addition

89

90

91

92

93

94

95

-40 -30 -20 -10 0 10 20 30

Days into ZSM-5 Usage

Gas

olin

e R

esea

rch

Oct

ane

ZSM-5 Additive Provided an Immediate

1.8 RON Gain

www.gbhenterprises.com

Page 44: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

2

4

6

8

10

12

64 68 72 76 80 84

Conversion (wt%)

C3=

(wt%

)

ECAT 521°C ECAT 543°C ECAT 566°C 4% Additive 521°C 4% Additive 543°C 4% Additive 566°C

DCR Testing of ZSM-5 Additive: Propylene Yield

www.gbhenterprises.com

Page 45: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

7

9

11

13

15

17

64 68 72 76 80 84

Conversion (wt%)

Tot

al C

4= +

iC4

(wt%

) DCR Testing of ZSM-5 Additive: Alky

Feed Yield

ECAT 521°C ECAT 543°C ECAT 566°C 4% Additive 521°C 4% Additive 543°C 4% Additive 566°C

www.gbhenterprises.com

Page 46: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Yield and Octane Shifts With ZSM-5 Additives

Low octane gasoline components are converted to LPG olefins Gasoline composition changes:

decreased paraffins and olefins in "octane-dip" range increased light iso-paraffins increased light olefins increased aromatics (via concentration)

No change in coke, dry gas, or bottoms yield

Gasoline RONc and MONc increased

www.gbhenterprises.com

Page 47: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Environmental Additives

Page 48: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Sulfur Balance in an FCC Unit

F

C

C

Feed Sulfur Sulfides Thiophenes Benzothiophenes Multi-ring Thiophenes

Light Gases, H2S 20 - 60%

Gasoline 2 - 10%

Light Cycle Oil 10 - 25 %

Heavy Cycle Oil 5 - 35 %

Coke, SOx 2 - 30 %

• FCC gasoline typically contributes >90% of the total gasoline pool sulfur • Up to 50% of FCC gasoline sulfur is usually concentrated in the back end of the gasoline

www.gbhenterprises.com

Page 49: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Catalytic SOx Reduction

PRODUCTS ( with H2S )

MeSO4 (s) + 4 H2 (g) = MeS (s) + 4 H2O (g)

RISER: Reduction of Metal Sulfate

MeSO4 (s) + 4 H2 (g) = MeO (s) + H2S (g) + 3 H2O (g)

Stripping Steam

STRIPPER: Hydrolysis of Metal Sulfide MeS (s) + H2O (g) = MeO (s) + H2S (g)

FEED ( with Sulfur )

FLUE GAS ( with SOx )

Regenerator Air

REGENERATOR: Formation of SOx S (coke) + O2 (g) = SO2 (g)

SO2 (g) + ½ O2 (g) = SO3 (g)

Formation of Metal Sulfate SO3 (g) + MeO (s) = MeSO4 (s)

www.gbhenterprises.com

Page 50: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

FEED SULFUR IN GASOLINE vs GASOLINE CUT POINT

1

2

3

4

5

6

7

8

9

180 185 190 195 200 205 210 215 220 225 230 Gasoline C.P. (ºC)

Feed

Sul

phur

in G

asol

ine

(%)

W/O Additive Comp X

Comp X Allowed Refinery C to Reduce Sulfur by ca. 20-25%

www.gbhenterprises.com

Page 51: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

NOx Emissions: XNOx vs. Pt. Promoter

0

100

200

300

400

500

-1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0

NO

(ppm

)

Hours

Addition of 0.5% XNOx

Addition of Pt based Promoter

60% Reduction

www.gbhenterprises.com

Page 52: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Catalyst Manufacturing

Page 53: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Synthesis of Zeolite Y

NaSiO3 NaAlO2

Al2(SO4)3 Seeds

ca. 100°C, 1-2 days www.gbhenterprises.com

Page 54: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Sulfate Aluminate

Silicate Aluminium

Sodium

Sodium

Seeds ML-Gel

Sulfate

Beltfilter

Effluent

Aluminium

Water

Beltfilter Na-Y Zeolite

ZEOLITE PLANT (Part 1)

RE-Y Zeolite

(NH4)2SO4

RECl3 /

Water

Beltfilter

Effluent

NH4-Y /

www.gbhenterprises.com

Page 55: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Bag Filter System

Calciner

US-Y Zeolite CREY /

ZEOLITE PLANT (Part 2)

RE-Y Zeolite

NH4-Y /

Hot Air

Dryer

www.gbhenterprises.com

Page 56: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Binder Water Clay

Mixing

Water

Calciner

CATALYST FCC

FCC PLANT

Water

Beltfilter LS-USY

(NH4)2SO4

Effluent

RECl3 /

WET END

Spray Drier

Hot Air

Scrubbing System

DRY END

Zeolite (e.g.. CREY/USY)

Mixing

www.gbhenterprises.com

Page 57: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Reaction Chemistry

Page 58: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Boiling Range Distribution of FCC Feed and Products

Wt%

FF

Boiling Point, °C

Gas LPG Naphtha LCO Slurry /

FEED

Feedstock 40

0°C

221°

C

C4

C2

PRODUCTS

www.gbhenterprises.com

Page 59: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Hydrocarbon Types CHAIN STRUCTURES

Paraffin

H H H H

H H H H

R R

H H H H H H

RING STRUCTURES

Olefin

H H H

H H H H

R R

H H H H H

Naphthene

H

H H

H R

H H H

H H

H H

R

H H

H H H

H

H

Alkylaromatic H

H H

H H

H H H H

R R

H H

H

Crackability (Conversion): Paraffinic > Naphthenic > Aromatic

Coke-forming tendency (Heat Balance): Paraffinic < Naphthenic < Aromatic

www.gbhenterprises.com

Page 60: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Principles of Catalysis

Catalysts Lower Activation Energies of Forward & Backwards Reactions, Increasing the Rates of Both The Heat of Reaction is Unchanged by the Catalyst The Position of Thermodynamic Equilibrium is Unchanged by the Catalyst Non-Equilibrium Distributions Occur Under Kinetic Controlled Conditions

Free

Ene

rgy

Reaction Co-ordinate

ECatalytic

∆ Hreaction

EThermal

EB

EA

www.gbhenterprises.com

Page 61: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

0

50

100

150

Thermal vs Catalytic Cracking n-Hexadecane @ 500°C

Mol

es P

rodu

ct /

100

Mol

es C

rack

ed

Carbon Number

C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11 C12 C13 C14

Catalytic Cracking

Thermal Cracking

www.gbhenterprises.com

Page 62: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Principle Reactions in FCC

Olefins Cracking Light Olefins

Isomerisation other Naphthenes

Naphthenes Cracking Olefins

Transalkylation other Aromatics

Aromatics Side-chain Cracking

unsubstituted Aromatics + Olefins

Dehydrogenation poly-Aromatics

Dehydrogenation Coke

Condensation Condensation

Dehydrogenation cyclo-Olefins

Dehydrogenation Aromatics

Cracking Paraffins + Olefins Paraffins

H Transfer Paraffins

Condensation Cyclisation

Naphthenes Dehydrogenation

Coke

Olefins Paraffins Isomerisation H Transfer Branched Branched

www.gbhenterprises.com

Page 63: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

β - Scission (cracking) Reactions

Page 64: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Cracking Reaction Mechanism

H+

Si O

Al O

Si O -

Catalyst (Acid Site)

H H H H

H H H H

R R

H H H H

Carbenium Ion H

H H H

H H H

R R

H H H H

+

H H

Protonation

H H H H

H H H

R R

H H H H

+ H H

ß-scission

Olefin Product

H H

H H

R

H H H H

+

H H

H

R H

H

H H

H H

R

H H H H

+

H H

H

H H

R H

H

+ H

Intermolecular Rearrangement

H H

H

H H

R H

H

+ H

H H

H H

R H

H

H

Deprotonation

-

H+ www.gbhenterprises.com

Page 65: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Thermal Reaction Mechanism

Thermal cracking gives high yields of methane, alpha-olefins and ethylene, no increased branching

H H

H H H

H H H H H

H R

H H H H

Free radical formation

- H . Secondary Free radical

H H H H

H H

R

H H H

H H H

H

H .

ß-scission (Cracking)

Primary Free radical

. H H

H H

H H

R

H H

alpha- Olefin Product

H

H H

H

H H

ß-scission (cracking) Ethylene

H

H

H H

New free radical

H H

H

R

H

.

homolytic fission

C H homolytic fission

C C homolytic fission

C C

www.gbhenterprises.com

Page 66: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Summary of Cracking Reactions

Relative Cracking Rates: Olefin > Naphthene = Alkylaromatic > Paraffin

Olefins most readily form carbocations

Aromatic side-chains readily undergo cracking reactions, however, aromatic rings do not crack

Alkylaromatic Alkylaromatic + Olefin

Naphthene Olefin

Paraffin Paraffin + Olefin

Olefin Olefin + Olefin

www.gbhenterprises.com

Page 67: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Hydrogen Transfer Reactions

Page 68: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

olefin + naphthene paraffin + cyclo-olefin

Hydrogen Transfer Reactions

olefin + cyclo-olefin paraffin + cyclo-diolefin olefin + cyclo-diolefin paraffin + aromatic

H

CH - CH2

CH2 - CH2 CH - R” H2 C

R - CH - CH2 - R’ +

H+ R - CH = CH - R’

olefin protonation

R - CH - CH - R’ H

+

hydrogen transfer

H

R - CH - CH2 - R’

CH - CH2

CH2 - CH2 CH - R” H2 C

+

H

CH - CH

CH2 - CH2 CH - R” H2 C

+ CH = CH

CH2 - CH2 CH - R” H2 C - H+

proton loss

www.gbhenterprises.com

Page 69: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Heat Balance Considerations

Page 70: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

FCC Heat Balance Considerations

Most FCC process variables have an effect on the heat balance - which, in turn, affects: Conversion, Yields and Product Qualities

The FCC unit will always adjust itself to remain in heat balance by burning enough coke for the energy requirements

www.gbhenterprises.com

Page 71: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Heat Demands are Satisfied by Burning Coke

∆H air

ENERGY IS REQUIRED TO

HEAT AIR

∆H cracking

ENERGY IS REQUIRED TO CRACK FEED

∆H vaporization

ENERGY IS REQUIRED TO

VAPORISE FEED

∆H losses

ENERGY IS REQUIRED FOR

HEAT LOSSES TO ATMOSPHERE

www.gbhenterprises.com

Page 72: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

FCC Delta Coke Types

Occluded Feed Metals Catalytic

unstripped hydrocarbons (product to regenerator) high hydrogen content uncracked heavy feed components e.g. asphaltenes, Conradson carbon residue Formed via dehydrogenation activity of contaminant metals e.g. nickel, vanadium formed as a bi-product of desired catalytic cracking

15%

15%

5%

65%

VGO 14%

28%

28%

30%

Resid

www.gbhenterprises.com

Page 73: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Feed Dependence of Delta Coke

Contaminant Coke (Metals Coke) Increases

Feed Residue Coke (Conradson Carbon) Increases

Occluded Coke (Cat/Oil Coke) Same / Slight Increase

Catalytic Coke (Conversion Coke) Decreases

Contaminant Coke

Feed Residue Coke

Occluded Coke 0.10

0.30

0.50

0.80

1.60

Del

ta C

oke

Catalytic Coke

Decreasing Feed Quality Increasing: Density, ConCarbon, Metals, S, N.

Increasing Resid Content Increasing Ca/Cp ratio, Endpoint

www.gbhenterprises.com

Page 74: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Conversion Dependence on Delta Coke

Lower conversion by :

higher regen. temperature

lower cat/oil (lower severity)

Lower effective activity due to :

coke blockage of pores

metals contamination

increased nitrogen poisoning

FCC

Uni

t Con

vers

ion Regen T

Cat/Oil Ratio

Unit Conversion

Delta Coke, wt.%

Increasing Resid content

Constant Riser Outlet Temp. Constant Coke Operation (Unit at Max. Blower Capacity)

www.gbhenterprises.com

Page 75: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Selecting the Right Combination

Page 76: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Gasoline Mode Operation

Page 77: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

FCC Optimization for Gasoline Production

high Zeolite / Matrix ratio (Z/M) high Hydrogen Transfer (high ucs) high Catalyst Activity (Conversion)

C3=, C4='s for cat. polym. C3= for dimersol / petrochem. C3's, C4's for LPG

C3=, C4='s, i-C4 for alkylation i-C4= for MTBE

Fuel Gas H2, C1, C2, C2=

Gasoline C5 - 221°C Kerosene 150 - 250°C

Cat. Heating Oil

Diesel 200 - 350°C

FCC UNIT

Crude Atmospheric Column

Straight Run Products

Atmospheric Residue Vac. Gas Oil

Vacuum Residue

Vacuum Column

Residue Hydrotreater

HT Resid

Gasoline Selectivity is favored by:

www.gbhenterprises.com

Page 78: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

FCC Optimization for Gasoline Production

high Catalyst / Oil ratio moderate Riser Outlet Temperature high ECat Activity (MAT)

C3=, C4='s for cat. polym. C3= for dimersol / petrochem. C3's, C4's for LPG

C3=, C4='s, i-C4 for alkylation i-C4= for MTBE

Fuel Gas H2, C1, C2, C2=

Gasoline C5 - 221°C Kerosene 150 - 250°C

Cat. Heating Oil

Diesel 200 - 350°C

FCC UNIT

Crude Atmospheric Column

Straight Run Products

Atmospheric Residue Vac. Gas Oil

Vacuum Residue

Vacuum Column

Residue Hydrotreater

HT Resid

Gasoline Selectivity is favored by:

www.gbhenterprises.com

Page 79: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Distillate Mode Operation

Page 80: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

FCC Optimization for Middle Distillates

Production

high Matrix Activity (lower Z/M) high Hydrogen Transfer (high ucs) low Catalyst Activity (low Conversion)

C3=, C4='s for cat. polym. C3= for dimersol / petrochem. C3's, C4's for LPG

C3=, C4='s, i-C4 for alkylation i-C4= for MTBE

Fuel Gas H2, C1, C2, C2=

Gasoline C5 - 221°C

Kerosene 150 - 250°C

Cat. Heating Oil

Diesel 200 - 350°C

FCC UNIT

Crude Atmospheric Column

Straight Run Products

Atmospheric Residue Vac. Gas Oil

Vacuum Residue

Vacuum Column

Residue Hydrotreater

HT Resid

Middle Distillate Selectivity is favored by:

www.gbhenterprises.com

Page 81: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

FCC Optimization for Middle Distillates

Production

low Catalyst / Oil ratio low Riser Outlet Temperature low ECat Activity (MAT) use of Recycle (HCO/Slurry)

C3=, C4='s for cat. polym. C3= for dimersol / petrochem. C3's, C4's for LPG

C3=, C4='s, i-C4 for alkylation i-C4= for MTBE

Fuel Gas H2, C1, C2, C2=

Gasoline C5 - 221°C

Kerosene 150 - 250°C

Cat. Heating Oil

Diesel 200 - 350°C

FCC UNIT

Crude Atmospheric Column

Straight Run Products

Atmospheric Residue Vac. Gas Oil

Vacuum Residue

Vacuum Column

Residue Hydrotreater

HT Resid

Middle Distillate Selectivity is favored by:

www.gbhenterprises.com

Page 82: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Light Olefins Mode Operation

Page 83: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

FCC Optimization for Light Olefins Production

low Hydrogen Transfer (low ucs) use of ZSM-5 Zeolite containing additives high Catalyst Activity (very high Conversion)

C3=, C4='s for cat. polym. C3= for dimersol / petrochem. C3's, C4's for LPG

C3=, C4='s, i-C4 for alkylation i-C4= for MTBE

Fuel Gas H2, C1, C2, C2=

Gasoline C5 - 221°C

Kerosene 150 - 250°C

Cat. Heating Oil

Diesel 200 - 350°C

FCC UNIT

Crude Atmospheric Column

Straight Run Products

Atmospheric Residue Vac. Gas Oil

Vacuum Residue

Vacuum Column

Residue Hydrotreater

HT Resid

Light Olefin Selectivity is favored by:

www.gbhenterprises.com

Page 84: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

FCC Optimization for Light Olefins Production

high Riser Outlet Temperature high Catalyst / Oil ratio high ECat Activity (MAT)

C3=, C4='s for cat. polym. C3= for dimersol / petrochem. C3's, C4's for LPG

C3=, C4='s, i-C4 for alkylation i-C4= for MTBE

Fuel Gas H2, C1, C2, C2=

Gasoline C5 - 221°C

Kerosene 150 - 250°C

Cat. Heating Oil

Diesel 200 - 350°C

FCC UNIT

Crude Atmospheric Column

Straight Run Products

Atmospheric Residue Vac. Gas Oil

Vacuum Residue

Vacuum Column

Residue Hydrotreater

HT Resid

Light Olefin Selectivity is favored by:

www.gbhenterprises.com

Page 85: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Short Contact Time Operation

Page 86: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

FCC Optimization for Short Contact Time

Operations

high Catalyst Activity balanced Zeolite/Matrix ratio (Z/M) high Hydrogen Transfer (high ucs)

C3=, C4='s for cat. polym. C3= for dimersol / petrochem. C3's, C4's for LPG

C3=, C4='s, i-C4 for alkylation i-C4= for MTBE

Fuel Gas H2, C1, C2, C2=

Gasoline C5 - 221°C Kerosene 150 - 250°C

Cat. Heating Oil

Diesel 200 - 350°C

FCC UNIT

Crude Atmospheric Column

Straight Run Products

Atmospheric Residue Vac. Gas Oil

Vacuum Residue

Vacuum Column

Residue Hydrotreater

HT Resid

Short Contact Time Operation is favored by:

www.gbhenterprises.com

Page 87: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

FCC Optimization for Short Contact Time

Operations

high Riser Outlet Temperature high Catalyst / Oil ratio high ECat Activity (MAT)

C3=, C4='s for cat. polym. C3= for dimersol / petrochem. C3's, C4's for LPG

C3=, C4='s, i-C4 for alkylation i-C4= for MTBE

Fuel Gas H2, C1, C2, C2=

Gasoline C5 - 221°C Kerosene 150 - 250°C

Cat. Heating Oil

Diesel 200 - 350°C

FCC UNIT

Crude Atmospheric Column

Straight Run Products

Atmospheric Residue Vac. Gas Oil

Vacuum Residue

Vacuum Column

Residue Hydrotreater

HT Resid

Short Contact Time Operation is favored by:

www.gbhenterprises.com

Page 88: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Gasoline Olefins Reduction

Page 89: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

FCC Optimization for Gasoline Olefins

Reduction

high Zeolite / Matrix ratio (Z/M) high Hydrogen Transfer (high ucs) moderate Matrix Activity (SAM-700) high Metals Tolerance (e.g. Ni and V)

C3=, C4='s for cat. polym. C3= for dimersol / petrochem. C3's, C4's for LPG

C3=, C4='s, i-C4 for alkylation i-C4= for MTBE

Fuel Gas H2, C1, C2, C2=

Gasoline C5 - 221°C Kerosene 150 - 250°C

Cat. Heating Oil

Diesel 200 - 350°C

FCC UNIT

Crude Atmospheric Column

Straight Run Products

Atmospheric Residue Vac. Gas Oil

Vacuum Residue

Vacuum Column

Residue Hydrotreater

HT Resid

Gasoline Olefins Reduction is favored by:

www.gbhenterprises.com

Page 90: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

FCC Optimization for Gasoline Olefins

Reduction

high Catalyst / Oil ratio low Riser Outlet Temperature high ECat Activity high Conversion

C3=, C4='s for cat. polym. C3= for dimersol / petrochem. C3's, C4's for LPG

C3=, C4='s, i-C4 for alkylation i-C4= for MTBE

Fuel Gas H2, C1, C2, C2=

Gasoline C5 - 221°C Kerosene 150 - 250°C

Cat. Heating Oil

Diesel 200 - 350°C

FCC UNIT

Crude Atmospheric Column

Straight Run Products

Atmospheric Residue Vac. Gas Oil

Vacuum Residue

Vacuum Column

Residue Hydrotreater

HT Resid

Gasoline Olefins Reduction is favoured by:

www.gbhenterprises.com

Page 91: FCC Catalyst Design: Morphology, Physiology, Reaction Chemistry and Manufacturing

Questions ?