mcilvaine “hot topic hourhot topic hour” june 30, 2011 · mcilvaine “hot topic hourhot topic...

McIlvaine “Hot Topic Hour”McIlvaine Hot Topic Hour June 30, 2011

Fuel Impacts on Design andPerformance of SCR Catalysts

Presenter:John Cochran

Performance of SCR Catalysts

CERAM Environmental, Inc.+1 913 239 9896

[email protected]

Catalyst Deactivates With Time of Exposure to Flue Gasp

Ko (Original Catalyst Activity) ct

ivity

)

Coal/Heavy Pet Coke Blend

Coal Low Dust

Coal High Dust

(Rel

ativ

e A

c Coal High Dust

Biomass

Waste High Dust

K/K

o

K/Ko @ 16 khr

0 2000 4000 6000 8000 10000 12000 14000 16000

Operation [hrs]

Catalyst Design (at hour=0) Must Anticipate Deactivation to End of Guarantee Period (e.g., 16,000 hours) to Size Catalyst Properly

Catalyst Deactivation is Very Site SpecificVery Site Specific

K/Ko vs Time

0 9

1.0

0.7

0.8

0.9

vity

0.4

0.5

0.6

Rel

ativ

e A

ctiv

0.1

0.2

0.3R

0.00 2000 4000 6000 8000 10000 12000 14000 16000 18000 20000

Hours of SCR Operation

Varying Based on Fuel Quality and OperationsVarying Based on Fuel Quality and Operations

Catalyst Deactivation Mechanisms Gaseous Poisons: Gaseous Poisons:

Arsenic Phosphorus

P t i Act

ivity

)

Coal/Heavy Pet Coke Blend

Coal Low Dust

Coal High Dust Potassium Sodium Cadmium

L d

K/K

o (R

elat

ive

A

Biomass

Waste High Dust

Lead Copper Other Elements

0 2000 4000 6000 8000 10000 12000 14000 16000

Operation [hrs]

Fouling by Solid Compounds Gypsum (Calcium Sulfate) and Other Solid Compound Deposition Ammonium Bisulfate (Avoided by Keeping Above Permissive

T t )Temperatures) Occurs During...

Normal SCR OperationS d Sh d i G h h A id i Startups and Shutdowns as Unit Goes Through Acid Dew Point

Catalyst Deactivation Vanadium Titania Based Catalyst Deactivates Based on Site Specifics Vanadium-Titania Based Catalyst Deactivates Based on Site Specifics

Fuel Quality – Arsenic, Phosphorus, Potassium, Sodium, Sulfur, Calcium, etc.

Comb stion Q alit Increased S bstoichiometric Staging Increases Combustion Quality – Increased Substoichiometric Staging Increases Quantity of Gaseous Poisons

# of Startups and ShutdownsV di Tit i B d C t l t D ti t I d d t f Vanadium-Titania Based Catalyst Deactivates Independent of... Catalyst Type – Plate, Honeycomb, Corrugated Fiber Formulation – Different Activities and SO2:3 Conversion Rates Reference Also “Comparison of Deactivation Rates of Different

Catalyst Types” by Ed Healy, Southern Company and Hans Hartenstein, Evonik (now Steag) Presented February 9, 2009

h // i h ld i l / bli /47b 6d6 7 8f479388 20d66579738f8/H %20H i %20 ihttp://www.reinholdenvironmental.com/public/47bc6d6a7e8f479388a20d66579738f8/Hans%20Hartenstein%20presentation%20Deactivation%202009.pdf

Deactivation Resistance Comes From Providing Adequate Reactor Potential (RP=K/Av) – There Are No Magic Potions( ) g

Case Example 1: Two x 500 MW Unit PRB Deactivation Rate History

Being Considered

0.9

1.02 x 500 MW Units - Plate and Honeycomb Catalyst Deactivation Trends

0.7

0.8

ctiv

ity K

/Ko

0 4

0.5

0.6

Rel

ativ

e A

c

0.3

0.4

0 5,000 10,000 15,000 20,000 25,000 30,000 35,000 40,000 45,000 50,000Time of Exposure to Flue Gas, hours

Original Supplier’s (Plate by Others) Estimate of Deactivation RateU d B i f C t l t D i

K/Ko Design Basis of Original Plate Supplier Expected Deactivation Trend

Used as Basis for Catalyst Design


Being Considered

0.9


0.7

0.8

ctiv

ity K

/Ko

0 4

0.5

0.6

Rela

tive

Ac

0.3

0.4


Deactivation Rate Assumed by Original Plate Catalyst Supplier Proven to be Overly Optimistic


Plate Catalyst Test Results (Original Supplier)

Proven to be Overly Optimistic


Being Considered

0.9


0.7

0.8

ctiv

ity K

/Ko

0 4

0.5

0.6

Rel

ativ

e A

c

0.3

0.4


Deactivation Rate Assumed by Original Plate Catalyst Supplier Proven to be Overly Optimistic


Plate Catalyst Test Results (Original Supplier) Honeycomb Catalyst Test Results (2 Suppliers)

Proven to be Overly Optimistic Subsequent Replacements With Honeycomb Catalyst From 2

Different Suppliers Confirms Both Types Deactivate Based on The Same Trend

Case Example 2: 600 MW Unit Burning Eastern Bituminous High Arsenic/Low Calcium Coal

0.9

1

Relative Activity Vs Time600 MW Unit With High Arsenic and Low CaO

Fuels Burned Different Than

0 6

0.7

0.8

0.9

K/K

o)

Originally Specified Resulting in Extreme Deactivation

0 3

0.4

0.5

0.6

elat

ive

Act

ivity

(K

0

0.1

0.2

0.3

Re

Honeycomb Catalyst Test ResultsCorrugated Fiber Catalyst Test ResultsProjected DeactivationExpected Activity for Specified Fuel (16khr)Current Deactivation Trend (16khr)

00 5,000 10,000 15,000 20,000

Exposure to Flue Gas (hrs)

Original Deactivation Rate Underestimated Based on Change in Fuel S ifi iSpecification

Catalyst Test Results For Honeycomb and Corrugated Fiber Catalyst Confirms Both Types Deactivate Based on The Same Trend

Why is Estimating CatalystDeactivation So Important

If Deactivation is Underestimated Catalyst is Undersized I bl f M ti NO R l d A i Sli P f Incapable of Meeting NOx Removal and Ammonia Slip Performance

at Some Point During the Guarantee Period Deficient Performance is Either Tolerated or an Early Outage

(Unscheduled) is Required for Catalyst Addition(Unscheduled) is Required for Catalyst Addition Catalyst Management Costs are Underestimated

Understanding and Managing Reactor Potential Critical to Minimize RiskPotential Critical to Minimize Risk

Examples Help to Illustrate Risk

Reactor Potential

Can be represented by

P = K/AV

K = catalyst activity, Nm3/m2h or Nm/hAV = catalyst area velocity, Nm/h (normalized operating gas flow, Nm3/h divided by total installed catalyst surface area, m2)

DeNOx Demand Reactor Potential DeNOx Demand = The reactor potential required

to meet NOx removal and ammonia slip requirements at the specified operating conditionsrequirements at the specified operating conditions

Calculated based on NOX removal requirements, NH3 slip, SCR distributions, and boiler operating conditions (flow temperature pressure etc )conditions (flow, temperature, pressure, etc.)

Independent of catalyst design life (i.e. same value for 16,000 or 24,000 hour catalyst life)I d d t f C t l t T F l ti Independent of Catalyst Type, Formulation, or Manufacturer

DeNOx Demand, Reactor Potential, & Catalyst Design

1. Determine DeNOx Demand (Preq)

1. DeNOx demand (Preq) is the amount of reactor potential necessary to achieve NOx removal and ammonia slip performance based on fixed operating conditions (flows temp etc )and ammonia slip performance based on fixed operating conditions (flows, temp, etc.)


2 E ti t C t l t D ti ti (K /K )


2. Estimate Catalyst Deactivation (Ke/Ko) Varies as Function of Design Life


2. Catalyst deactivation is estimated based on fuel quality, combustion parameters, and design life


3. Determine Initial Reactor Potential


3. Determine Initial Reactor Potential Required (Po)




2. Catalyst deactivation is estimated based on fuel quality, combustion parameters, and design life3. Based on DeNOx demand and deactivation the initial reactor potential (Po) is determined


3. Determine Initial Reactor Potential


3. Determine Initial Reactor Potential Required (Po) 4. Determine Catalyst Volume

fn(Ko, geometry, SO2:3, gas, etc)




2. Catalyst deactivation is estimated based on fuel quality, combustion parameters, and design life3. Based on DeNOx demand and deactivation the initial reactor potential (Po) is determined4. Catalyst volume is determined based on Po, catalyst activity, geometry, SO2 to SO3 conversion y , y y, g y, 2 3

rate, and various gas conditions and constituents

Comparison of Catalyst Design Cases

1.6

)Proposal 1: 'Conservative' Design Case (0.65 K/Ko @16 khr)

1.4

or Poten

tial (K/AV Required Reactor Potential

Guaranteed Life

1.2

Relativ

e Re

acto

1.0

Proposal 1 Has the Most Conservative K/Ko Basis (0.65 @ 16,000 hr)

0.8

0 4000 8000 12000 16000 20000

Hours of Operation

p ( @ )

Comparison of Catalyst Design Cases

1.6


Proposal 2: 'Aggressive' Design Case (0.72 K/Ko @16 khr)Variance in Reactor Potential Consists of Volume, Surface Area and/or K Differences

1.4

or Poten

tial (K/AV

Required Reactor Potential

Guaranteed Life

Area and/or K Differences

1.2

Relativ

e Re

acto

1.0

Proposal 2 is Based on a More Aggressive Deactivation Rate (0.72 K/Ko)

0.8

0 4000 8000 12000 16000 20000

Hours of Operation

p gg ( ) Approximately 10% Difference in Catalyst Volume Who is Right?

Case A: Proposal 1 Deactivation Rate Correct

1.6


Proposal 2: 'Aggressive' Design Case (0.72 K/Ko @16 khr)

1.4

or Poten

tial (K/AV 0.72 K/Ko Based Proposal 2 Operating at 0.65 K/Ko @16 khr


Guaranteed Life

1.2

Relativ

e Re

acto

1.0

Reduced Catalyst Life Since Proposal 2 Was Undersized

Should a K/Ko of 0.65 Actually Occur Proposal 2 Would be Undersized

0.8

0 4000 8000 12000 16000 20000

Hours of Operation

y pand Meet Performance for Less Than 11,000 Hours

Early Outage Required or Reduced Performance Must be Accepted

Case B: Proposal 2 Deactivation Rate Correct

1.6


Proposal 2: 'Aggressive' Design Case (0.72 K/Ko @16 khr)

1.4

or Poten

tial (K/AV 0.65 K/Ko Based Proposal 1 Operating at 0.72 K/Ko @16 khr


Guaranteed Life

1.2

Relativ

e Re

acto

Increased Catalyst Life

1.0

Should a K/Ko of 0.72 Actually Occur Proposal 1 Would be Oversized

0.8

0 4000 8000 12000 16000 20000 24000 28000

Hours of Operation

y pand Meet Performance for More Than 24,000 Hours (>3 Years)

Catalyst Management Costs Greatly Reduced

Unstaged PRB Fired Units Catalyst Deactivation

Group 1: PRB Unit Catalyst Activity Test Results

1.0

1.2

0.6

0.8

tive

Act

ivity

K/K

o

0.2

0.4Rel

at

0.00 5,000 10,000 15,000 20,000 25,000 30,000 35,000 40,000 45,000 50,000

Exposure to Flue Gas, hours

Plant 7 PC Plant 8 PC

Plant 9 Cyclone Plant 10 PC

“Unstaged” PRB Units Indicate a K/Ko @ 16,000 hours of 0.6 to 0.8

Plant 9 Cyclone Plant 10 PC

Plant 11 PC Plant 12 Cyclone

Plant 13 Cyclone Plant 14 Cyclone

General Deactivation Trend - Unstaged PRB Units

g @ Wide Variation of Results Dependent on Many Operations and Fuel

Variables

Catalyst Deactivation for "Deeply Staged" PRB Units

Group 2: PRB Unit Catalyst Activity Test Results

1.0

1.2

o

Catalyst Deactivation for "Deeply Staged" PRB Units

0.6

0.8

ativ

e A

ctiv

ity K

/K

0.2

0.4Rel

a

Plant 1 PC Plant 2 PCPlant 3 Cyclone Plant 4 CyclonePlant 5 Cyclone Plant 6 PCOther Deeply Staged General Trend Plant 6 PC General Trend

0.00 5,000 10,000 15,000 20,000 25,000

Exposure to Flue Gas, hours

p y g

Combustion Conditions Greatly Affect PRB Application Deactivation Rates Combustion Conditions Greatly Affect PRB Application Deactivation Rates Broad Consensus of Results for “Deeply Staged” Units Confirm Severe Deactivation Highly Risky if Plant 6 Alone Was Selected as a Reference Unit to Support Proposal Sizing A Plant 6 Based Catalyst Design Will Last Less Than One Year on a 24,000 Hour Guarantee With y g ,

Deep Deactivation Seen for Broader Experience

Summary

Deactivation Rates Vary Widely Dependent on Site Specifics Fuel Quality, Combustion Parameters, and Boiler Duty Cycle Greatly

Affect Catalyst Deactivation Ratesy Vanadium-Titania Based Catalysts All Deactivate at the Same Rate Based on

Site Specifics Underestimating or Aggressive Sizing Compromises SCR Performance and Underestimating or Aggressive Sizing Compromises SCR Performance and

Effective Catalyst Management Risk of Early Outage for Catalyst Additions Risk of Deficient Performance

Initial SCR Project Design Should Carefully Consider Reactor Potential to Determine the Risk Profile of Various Proposalsp Aggressive Catalyst Designs Can Result in Operations Difficulties and

Increased Cost

mcilvaine “hot topic hourhot topic hour” june 30, 2011 · mcilvaine “hot topic hourhot topic...

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