1

Twenty Questions: Identify Probable Cause

of

High FCC Catalyst Loss

Steve Tragesser

Chief Technology Engineer – FCC and Alkylation

Presented by Ignacio Bincaz

ignacio.bincaz@kbr.com

KBR

Houston, Texas, USA

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KBR Technology Portfolio

z

Proprietary Equipment • Refining

• Olefins

• Chemicals

• Ammonia and

Fertilizers

• Evaporation and

Crystallization

• Acid Treatment

Refining • ROSE®

• VCC™

• FCC, MAXOFIN, MAXDIESEL

• Hydroprocessing

• Advanced Distillation

• K-SAAT™

• MAX-ISOM

Olefins

• SCORE™

• K-COT™

Ammonia and Fertilizers • Ammonia

• Weatherly Nitric Acid

• Weatherly Ammonium

Nitrate • Weatherly UAN

• Syngas, Coal Gasification

• Hydrogen

• Methanol

Automation and Process Technologies • InSite™ Performance

Monitoring

• OTS

• OMS

• Technical Services

Chemicals

• Phenol/Acetone

• BPA

• PVC

• Acetic Acid

• Vynil Acetate Monomer

• NExOCTANE™, NExETHERS™

• KBR Ecoplanning

Evaporation and Crystallization

• Plinke

Acid Treatment

KBR FCC HISTORY From the Very Beginning

• KBR was Co-Developer of FCC Process

• KBR Designed and Built the World’s First

FCC

• 1942 in Baton Rouge, Louisiana

• KBR Has Designed Over 120 New Units

• Revamped Over 150 units since 1985

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General Orientation FCC Catalyst Loss Troubleshooting

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Dozens of Possible Problems

Twenty Questions Provide Framework

Expect Corrupt and Conflicting Data – So do not jump to conclusions

Think Independently – But listen to what others are

saying

– Avoid searching for agreement among preconceptions

– Check and re-verify field observations first hand

Twenty Questions: First Things First

1. What is the relative rate of catalyst loss in the fractionator bottoms compared to normal?

2. What is the relative stack opacity or rate of fines catch compared to normal?

3. What is the relative amount of equilibrium catalyst in the 0-40 micron range?

4. What is the average equilibrium catalyst APS compared to normal?

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What is Normal ?

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Twenty Questions: First Things First

5. How does the volumetric flow rate of reactor product vapors through the cyclones compare to normal?

6. How does the volumetric flow rate of air or flue gas through the regenerator compare to normal?

7. How does the catalyst circulation rate compare to normal?

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Twenty Questions: Questions that require some legwork

8. What is the relative rate of catalyst loss from the regenerator compared to normal?

9. How does the fresh catalyst make-up rate compare to normal?

10.Are the losses steady or intermittent?

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5

Twenty Questions: Questions that require some legwork

11.When did you last change the type of fresh FCC Catalyst?

12.When did the loss increase first occur? - What else was going on at that time?

13.How long did it take for the losses to increase from a normal rate?

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Twenty Questions: Questions that are Harder to Answer

14.What is the relative angularity of the equilibrium catalyst?

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E-Cat from a unit suffering from

a mechanical attrition problem

100 μm

100 μm

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Twenty Questions: Questions that are Harder to Answer

15.What is the relative angularity of lost catalyst?

16.What is the relative APS of the catalyst in the reactor carryover?

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Fines from a unit suffering from

a mechanical attrition problem

50 μm

What is Normal ?

Attrition Source Identified

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A sudden rapid increase in stack opacity was observed.

The problem was traced to failure of steam distributor.

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Twenty Questions: Questions that are Harder to Answer

17.What is the shape of the differential particle size curve of the catalyst in the reactor carryover?

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Clues From Fines Analysis Reduced System Efficiency

PARTICLE SIZE DISTRIBUTION

0

1

2

3

4

5

6

7

8

9

10

0 10 20 30 40 50 60 70 80 90 100

PARTICLE SIZE

PE

RC

EN

T

Typical PSDPoor Second Stage Cyclone

Performance

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8

Clues From Fines Analysis Bi-Modal Distribution Indicating an Attrition Problem

PARTICLE SIZE DISTRIBUTION

BIMODAL PEAK

0

1

2

3

4

5

6

7

8

9

10

0 10 20 30 40 50 60 70 80 90 100

PARTICLE SIZE

PE

RC

EN

T

Attrition

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Clues From Fines Analysis Bi-Modal Distribution Indicating Cyclone Bypass

PARTICLE SIZE DISTRIBUTION

BIMODAL PEAK

0

1

2

3

4

5

6

7

8

9

10

0 10 20 30 40 50 60 70 80 90 100

PARTICLE SIZE

PE

RC

EN

T

Hole or Crack in Outlet Tube or Plenum

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Twenty Questions: Questions that are Harder to Answer

18.What is the relative APS of the catalysts in the regenerator carryover?

19.What is the shape of the differential particle size curve of the catalysts in the regenerator carryover?

20.How does the cyclone system pressure drop compare to normal?

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Clues From Fines Photomicrograph Any microscope can provide a quick check

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10 – 80 µm

catalyst

particles

recovered

from flue

gas when

dipleg is

blocked.

10 – 20 µm

catalyst

recovered

from flue

gas

normally

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Examples Possible Causes of High FCC Catalyst Losses

• Excessive Attrition • In Fluid Bed

• In Dilute Phase

• Plugged Cyclone Dipleg • Reactor Primary

• Regenerator Primary

• Reactor Secondary

• Regenerator Secondary

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Dipleg Plugging Source Identified

• When the unit was re-streamed after a blower outage, one of the three air distributors was plugged.

• Massive catalyst entrainment problem due to a second stage dipleg sealed in unfluidized bed.

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What can be done ON-LINE to correct a plugged regenerator cyclone dipleg?

• Normal operation following a transient cyclone overload may be restored by reducing the air rate to a very low level for several minutes

• Overfilled cyclone hoppers drain defluidized catalyst

• Pressure bump the unit

• Partially unload catalyst and refill

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What can be done to correct a plugged reactor cyclone dipleg ON-LINE?

• Lower the stripper bed level to unseal the diplegs

• Pressure bump the unit by changing the vessel operating pressure rapidly

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Possible Causes of High FCC Catalyst Losses

• Holes in Plenum

• Holes in Cyclone • Reactor Plenum

• Reactor First Stage

• Reactor Second Stage

• Regenerator First Stage

• Regenerator Second Stage

• Stuck Open Dipleg Flapper • Reactor Second Stage

• Reactor First Stage

• Regenerator Second Stage

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2nd

Stage

What can be done to correct a stuck-open or detached check valve ON-LINE?

• It may be possible to reduce catalyst losses by raising the bed level to seal the dipleg.

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Possible Causes of High FCC Catalyst Losses Excessive Dipleg Back-up

Catalyst Bed Level

Dipleg Catalyst Level

First Stage Cyclone

Second Stage

Cyclone

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• Reactor Cyclone Overload • High vapor rate

• High catalyst (circulation) rate

• Regenerator Cyclone Overload • High vapor rate

• High catalyst (entrainment) rate

• Excessive Catalyst Bed Level

Fluid Bed Catalyst Entrainment Rate A function of velocity and particle/vapor density

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Ve = Effective superficial vapor velocity, fps

ρp = Particle density, lb/cu. ft

ρg = Gas density, lb/cu. ft

e = Entrainment, lb cat / cu. ft vapor

Giuricich, N.L. and Kalen, B., “Dominant Criteria in FCC Cyclone Design”, Katalistiks’ 3rd Annual Fluid Cat Cracking Symposium

Based on 55 Micron APS and 0.038 cp Flue Gas Viscosity

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What can be done ON-LINE to correct a dipleg hydraulic problem?

• Reduce dipleg submergence by lowering the catalyst bed level

• Reduce vapor and/or catalyst circulation rates.

• Increase operating pressure.

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Possible Causes of High FCC Catalyst Losses Items that can cause low efficiency

• Design • Reactor Cyclones

• Regenerator Cyclones

• Regenerator Vessel

• Slurry Filter Recycle • Returning fines to the

reactor forces fines out regenerator

• Cyclone Refractory Damage or Roughness

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Possible Causes of High FCC Catalyst Losses Catalyst and Feedstock Issues

• Fresh Catalyst Issues • High Addition Rate

• High 0-40 micron content

• Too soft

• Low density

• Contaminates in Feed (Such as Na, V, Fe) • Sticky catalyst reduces regenerator loss

• So fines go out reactor

• Contaminants in Feed • Catalyst fuses and plugs regenerator cyclone dipleg

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What can be done ON-LINE to correct a catalyst induced loss problem?

• Order fresh catalyst with lower 0-40 micron content

• Change to a catalyst with higher particle density or increased attrition resistance

• Reduce fresh catalyst make up rate

• Note: Refiners may purposely add fresh catalyst with

high fines content, or low density, soft catalyst to improve the fluidity.

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Extraordinary Measures When conventional methods fail

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Cold Flow

Modeling

Radioactive

Tracers and

X-Ray Scans

Cyclone

Pressure

Testing

Computational

Fluid Dynamics

Modeling

Cat Loss Troubleshooting Conclusions • Establish a Normal Baseline

before You have Trouble

• Answer Questions Before Drawing Conclusions

• Then Rank the Possibilities • based on the Preponderance

of the evidence

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Twenty Questions

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“Once you eliminate

the impossible,

whatever remains, no

matter how

improbable, must be

the truth.”

– Arthur Conan Doyle, Sr.

(Scottish writer, creator

of the detective

Sherlock Holmes, 1859-

1930)

How Can FCC Design Affect NOx?

• Effective air and spent cat distribution • Minimize excess oxygen • Minimize CO promoter

• Counter-Current Regeneration • Low oxygen concentration at initial

combustion • NOx reacts with carbon at top of bed

to form N2

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Commercial NOx Emissions

0

5

10

15

20

25

30

0.0 1.0 2.0 3.0 4.0

Excess Oxygen in Flue Gas

% N

in

Co

ke t

o N

Ox

Side-by-Side

Combustor-type

KBR Counter-Current

REGENMAX™ BENEFITS

• Burns catalyst clean in partial CO combustion • Without requiring an increase in catalyst inventory or unit size

• Achieves this in a single, simple regenerator vessel • Less costly than building

two-stage regenerators

• Reduces entrainment • Cuts particulate emissions

from regenerator

• Reduces wear on regenerator cyclones

• Feedstock operating flexibility • Can switch to complete

combustion when desired

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BAFFLE REDUCES ENTRAINMENT

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

1 2 3 4

Superficial Gas Velocity (ft/s)

En

tra

inm

en

t (l

b/f

t³) Without RegenMax

With RegenMax

Questions?

Ignacio Bincaz

Director, Business Development – Latin America

Mobile: (+1) 713-254-7923

ignacio.bincaz@kbr.com