Gas Turbine SCR Performance Optimization and … MP290 Gas Turbine SCR Performance Optimization and Management T. D. Martz, L. J. Muzio Fossil Energy Research Corp. Laguna Hills, CA

MP2901

Gas Turbine SCRPerformance Optimization and

Management

T. D. Martz, L. J. MuzioFossil Energy Research Corp.

Laguna Hills, CA

McIlvaine Hot Topic HourFebruary 14, 2013

MP290

Gas Turbine SCR Systems

2

Simple Cycle GT SCR

750-850°F

MP290

Gas Turbine SCR Systems

3

Combined Cycle GT SCR

MP2904

Today’s Gas Turbine SCR Topics

• Troubleshooting- FERCo is a trusted 3rd party engineering services company- Extensive background with SCR (design, modeling, full scale testing)- Developed a process model for SCR design and troubleshooting

• Catalyst Inlet NH3/NOx Distribution and AIG Tuning- Why NH3/NOx distribution is important- How AIG tuning can extend catalyst life- FERCo’s approach to AIG tuning

• SCR Catalyst Management- What is it?- How is it done?- Why is it done?

MP290

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NOx, ppm

NH

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Compliance Test

ComplianceWindow

Troubleshooting

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NH3 slip is too high…Why?

MP290

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NOx, ppm

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ComplianceWindow

Why?

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Catalyst Activity (K)?

Reactor Potential?

Flue GasBypass?

Poor NH3/NOx Distribution?

• F(material, geometry)• Condition of active sites

• Ability of the catalyst bed to reduce NOx• RP= K * Asp* Vcat/ Qfg

• Uniform NH3/NOx profile is critical• Local NH3/NOx >1 creates NH3 slip

• Any leakage around the catalyst increases stackNOx & NH3

MP290

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NOx, ppm

NH

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Compliance TestExpected (RMS=10%)RMS=30%Bypass

Activity, NH3 Distribution, or Bypass?

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• FERCo utilizes a process model to compare expected SCR performanceto actual performance (see curves below)

• A single data point is not sufficient for identifying the problem

MP290

Perform Additional Tests

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NH

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MP290

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NOx, ppm

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Compliance TestExpected (RMS=10%)RMS=30%Bypass

Flue Gas Bypass?

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NH3 slip at high NOxsuggests flue gas bypass

Poor NH3/NOx distribution does not explain NH3 slip at high NOx levels

MP29010

Catalyst Inlet NH3/NOx Distributionand AIG Tuning

MP290

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70 80 90 100NOx Reduction, %

NH3 Slip, ppm

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NH3/NOx Distribution and AIG Tuning

New Catalyst

Near CatalystEnd-of-Life

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NH3 Slip, ppm

RMS=5% RMS=10% RMS=15% RMS=25%

Catalyst Aging

MP29012

Sample Probe Grid Expedites Tuning

• AIG tuning is difficult withouta probe grid at the catalyst exit

• The costs for installing a probegrid will be recovered in the longrun:- No scaffolding or manlift required for

testing ($, safety issues)- Reduced test times (no manual probe)- Reduced testing contractor costs- More data

50MW simple cycle SCRWith a grid of 50 sample probes(5 x 10)

MP29013

Sample Probe Grid Expedites Tuning

MP29014

Sample Probe Grid Expedites Tuning

A sample grid is especiallyimportant for larger units(e.g., more than 30’ wide)

325MW combined cycle SCRwith a 36-point sample grid(6 x 6)

MP29015

FERCo’s Multipoint Instrumentation

- Samples 48 points in 15 minutes- NOx and O2

MP29016

• Some systems have no AIG adjustment valves – bad idea! No flexibility to account for 1) duct velocity gradients, 2) duct NOx gradients, or 3) lance-to-lance ammonia flow gradients

• Most systems have one-dimensional adjustability

• Ideal design: multiple zone adjustability

AIG Design Influences Tuning

Multiple zones allow treatment oflocalized gradients

NH3Vertical adjustability can handle only vertical velocity or inlet NOx gradients

MP29017

AIG Tuning, 10 MW Gas Turbine SCR

As-Found Adjusted

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Duct Bottom (ft)

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0.70.750.80.850.90.9511.051.11.151.21.251.31.351.41.451.51.55

Riverside Springs Unit 4 SCRBaseline NH3/NOx Distribution,

Catalyst Inlet

RMS = 22%

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Duct Bottom (ft)

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0.70.750.80.850.90.9511.051.11.151.21.251.31.351.41.451.51.55

Riverside Springs Unit 4 SCRNH3/NOx Distribution, Adjustment #1

Catalyst Inlet

RMS = 13%

NH3/NOx Distribution NH3/NOx Distribution

One-Dimensional,Vertical AIG

NH3

Adjustments across the widthnot possible

MP29018

AIG Tuning, 350MW Combined Cycle SCRAs-Found Outlet

NOx (ppm)Optimized Outlet

NOx (ppm)

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NH3 consumption reduced by 5%

One-Dimensional,Vertical AIG

NH3

Adjustments across the widthnot possible

MP29019

Duct Burners Impact AIG TuningDuct Burners Off(Inlet NOx ppm)

Duct Burners On(Inlet NOx ppm)

AIG Tough to Tune

NH3

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MP29020

AIG Tuning, 10 MW Gas Turbine SCR, 90° Turn

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As-Found AdjustedNormalized NH3/NOx Distribution

Multiple zones,skewed basedon flow modeling

RMS = 32% RMS = 13%

Normalized NH3/NOx Distribution

Corners adjusted

MP29021

SCR Catalyst Management

MP29022

SCR Catalyst Management

• What is catalyst management?- Keeping track of catalyst activity to ensure continued compliance

• How is catalyst management done?- Periodically determining the activity of the catalyst in the reactor- Laboratory analysis (if a sample can be obtained)- In situ analysis (later discussion topic)- Utilize catalyst management software for planning

• Why is it done?- Forecast when catalyst additions or replacements are necessary- Provide sufficient lead time to procure catalyst (6-9 months)

MP29023

Catalyst Activity Degrades With Time

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K/Ko

NH3 Slip, p

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Operating Hours

NH3 Slip‐Model K/K0

Monitoring ammonia slip is also critical

MP29024

In Situ Catalyst Activity Measurement*

Traditional Lab Measurement• Typically one per year• Currently no test protocol

KLab = -AVdesign ln(1-ΔNOx)Lab

@NH3/NOx=1-1.5

FERCo’s CatalysTrak®*

• in situ measurement• No outage required

KIn-situ = -AVactual ln(1-ΔNOx)full scale@NH3/NOx>1 locally

* Patented Process

MP29025

Questions?

www.ferco.com