ACHIEVING UNIFORM COMBUSTION USING REAL …ferco.com/Files/MP220-Power-Gen2005.pdf · achieving...

MP220

ACHIEVING UNIFORM COMBUSTION USING REAL TIME COAL FLOW AND

GASEOUS EMISSIONS MEASUREMENT EQUIPMENT

Frederick P. Haumesser, P.E.Richard E. Thompson, P.E.Fossil Energy Research Corp

Douglas L. EakleAllegheny Energy Supply

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EVIDENCE OF NON-UNIFORM COMBUSTION

Symptoms Of Non-Uniform Combustion Often Include:

• Uneven Excess Oxygen Readings (Side-To-Side)• Inconsistent Flyash Loss On Ignition (LOI) Values

And Localized High Carbon Monoxide (CO)• Uneven Waterwall Deposition Patterns• Side-To-Side O2, CO And NOx Data Change With

Firing Pattern • Uneven Flue Gas And Steam Temperatures

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WHY BALANCE THE STEAM GENERATOR’S COMBUSTION?

Non-Uniform Combustion Can Lead To:• Poor Equipment Performance• Increased Flyash Loss On Ignition (LOI) And

Increased Carbon Monoxide (CO) Resulting In Lower Boiler Efficiency

• Waterwall Corrosion And Fouling In The Convective Section

• Elevated NOx Emissions Caused By Air Rich Burners

• Elevated CO Emissions Caused by Fuel Rich Burners

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STEP ONE:

Address Pipe-to-Pipe Fuel Flow Distributions

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MEASURING AND OPTIMIZING COMBUSTION –COAL FLOW DISTRIBUTION TESTING

• Extractive Sampling (RotorProbeTM ) Versus Real Time Coal Flow Measurements

• RotorProbeTM :– ISO Approved– Performed Well Under Most Test Conditions In FERCo’s

Evaluations And At The EPRI Coal Flow Test Loop– Sequential, “Snapshot” Testing

• MIC:– Real-Time Coal Flow Distributions – Data Logged Constantly For All Burner Lines Of A Pulverizer– Field Testing Confirmed Accuracy With RotorProbeTM Results– Data From The EPRI Test Loop Indicated Very Good

Agreement

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MIC REAL TIME COAL FLOW DISTRIBUTION TESTING

• Two (Vertical Piping) or Three (Horizontal Piping) Sensors Required Per Burner Line

• Attach To Burner Line Using Existing Sample Ports (Valves)

• Data Logged And Displayed Simultaneously For All Burner Lines

• Distribution Changes Due To Operating Conditions, Such As Feedrate, Or To Equipment Settings, Such As Adjustable Orifices, Can Be Seen Immediately

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TYPICAL MIC SENSOR SET-UP

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STEP TWO:

Address Flue Gas Distributions for O2, CO and NOx (Side-to-Side)

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MEASURING AND OPTIMIZING COMBUSTION –GASEOUS EMISSIONS DISTRIBUTION TESTING

• Traditional (Point-To-Point) or Real Time Using the FERCo Multipoint Combustion Diagnostic Analyzer (MCDA)

• Traditional Sampling:– Perform Flue Gas Analysis Sequentially, Requiring

Approximately 3-5 Minutes Per Point (24 Points = 72-90 Minutes)

– Boiler May Change, Thus Initial Data May Not Be Representative

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• MCDA:– Perform Flue Gas Sampling Of Points In Parallel; 12

Points Can Be Sampled Simultaneously; 24 Points = 10-13 Minutes

– Data Logged Automatically Every 10-20 Seconds And Can Be Replayed For Additional Analyses

– Data Can Be Monitored In Real Time To See The Cause And Effect Relationships Of Operating Parameter And Equipment Changes, Such As Mill Loadings Or Air Register Settings

– MCDA Data Compared With Traditional CEM Instruments For Increased Confidence

MEASURING AND OPTIMIZING COMBUSTION –GASEOUS EMISSIONS DISTRIBUTION TESTING (Cont’d)

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TYPICAL MULTIPOINT NO, O2, CO ANALYZER (MCDA) INSTALLATION

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CASE HISTORY:

Combustion Diagnostics Using Real Time Instrumentation

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UNIT DESCRIPTION

• Allegheny Energy Supply’s Harrison Unit 2• 640 MWg• Foster-Wheeler Supercritical Boiler• Opposed Wall Fired• Six D9 Ball Tube Mills With Four Burner

Lines Per Mill• Firing Pattern: Three Elevations With Four

Burners Across For Both Walls

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NON-UNIFORM COMBUSTION SYMPTOMS ON HARRISON UNIT 2

• High CO And LOI On One Side Only• Increased LOI Forced Operators To

Increase Excess Air• Higher Excess Air And High LOI Caused

Decreased Electrostatic Precipitator (ESP) Performance

• The Increased Ash In The Flue Gas Leaving The ESP Was Eroding An Induced Draft Fan

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DIAGNOSTIC METHODOLOGY

• Perform Fuel Distribution Testing• Evaluate PC Samples For Fineness• Measure Concentrations of O2, CO and

NOx At Economizer Exit• Establish Cause And Effect Relationships

By Varying O2 Level, Firing Pattern, Mill Loading And Burner Register Settings

• Program Completed Within Seven Test Days

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HARRISON 2E MILL COAL FLOW DISTRIBUTION DATA

• F-W BALL TUBE MILLS WITH 4 – 15¼” BURNER LINES

ROTORPROBE™ RECOVERED MASSES: Pipe 1 Pipe 2 Pipe 3 Pipe 4 (Four Minute Collection Period) Run 1 235gm 230gm 93gm 117gm Run 2 186gm 217gm 125gm 221gm Run 3 277gm 208gm 71gm 176gm CALCULATED % DEVIATION PIPE TO PIPE 20.0% 24.2% -39.4% -4.8%

• MIC % DEVIATIONS PIPE TO PIPE 20.8% 42.5% -42.0 -21.3% (MIC Data Recorded Over 4 ½ Hours)

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MIC PLOT OF COAL FLOW DISTRIBUTIONS OVER TIME FOR 2E PULVERIZER

Mill 2E Burner Line Coal Flow Distributions

0

5

10

15

20

25

30

35

40

45

50

9:00

:44

AM

9:06

:30

AM

9:12

:15

AM

9:18

:01

AM

9:23

:47

AM

9:29

:32

AM

9:35

:18

AM

9:41

:03

AM

9:46

:49

AM

9:52

:35

AM

9:58

:20

AM

10:0

4:06

AM

10:0

9:51

AM

10:1

5:37

AM

10:2

1:23

AM

10:2

7:08

AM

10:3

2:54

AM

10:3

8:39

AM

10:4

4:25

AM

10:5

0:11

AM

10:5

5:56

AM

11:0

1:42

AM

11:0

7:28

AM

11:1

3:13

AM

11:1

8:59

AM

11:2

4:44

AM

11:3

0:30

AM

11:3

6:16

AM

11:4

2:01

AM

11:4

7:47

AM

11:5

3:33

AM

11:5

9:18

AM

12:0

5:04

PM

12:1

0:50

PM

12:1

6:35

PM

12:2

2:21

PM

12:2

8:06

PM

12:3

3:52

PM

12:3

9:38

PM

12:4

5:23

PM

12:5

1:09

PM

12:5

6:55

PM

1:02

:40

PM

1:08

:26

PM

1:14

:12

PM

1:19

:57

PM

1:25

:43

PM

Time

Perc

ent C

oal F

low

Dis

trib

utio

n

Pipe 1 Pipe 2 Pipe 3 Pipe 4

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THE EFFECT OF 2E MILL ON COMBUSTION UNIFORMITY WITH ALL MILLS IN-SERVICE

0 5 10 15 20 25 30 35 40 45 50 55 60A side Duct Width, ft (Gas Flow Out of Page) B side

NO corrected 297 ppmc ( 0.405 lb/MBtu )

0

2

4

6

8

10

12

Top

D

epth

, ft

B

otto

m

299

296

299

303

316

315

321

288

287

281

285

287

283

282

293

290

291

286

275

296

285

251

262


CO corrected 194 ppmc

0

2

4

6

8

10

12

Bot

tom

D

epth

, ft

To

p

58

71

52

31

7

5

3

26

16

22

20

32

23

57

82

17

161

412

958

232

475

1333

1400


O2 4.14%

0

2

4

6

8

10

12

Bot

tom

D

epth

, ft

To

p

3.7

3.3

3.6

3.8

4.2

4.3

4.0

4.2

4.2

4.3

4.1

4.4

4.1

4.1

4.0

4.2

4.2

4.0

3.5

4.5

4.2

3.1

3.1

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NO corrected 316 ppmc ( 0.431 lb/MBtu )

0

2

4

6

8

10

12

Top

D

epth

, ft

B

otto

m

297

299

300

308

315

321

317

308

303

305

311

306

301

301

317

308

317

311

306

318

308

286

301


CO corrected 4 ppmc

0

2

4

6

8

10

12

Bot

tom

D

epth

, ft

To

p

16

21

20

18

3

2

0

4

3

-1

-1

1

3

0

1

2

3

3

6

2

5

6

8


O2 5.25% E MOOS

0

2

4

6

8

10

12

Botto

m

Dep

th, f

t

Top

3.7

3.4

3.9

4.1

4.6

5.2

4.3

5.6

5.7

5.9

5.6

5.5

5.0

5.1

5.2

5.0

5.3

5.3

5.2

5.3

5.3

4.5

5.0

THE EFFECT OF 2E MILL ON COMBUSTION UNIFORMITY WITH 2E MILL OUT OF SERVICE

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COMBUSTION IMPROVEMENTS

• CO Was Reduced From 194 ppmc To 4 ppmc

• O2 Increased From 4.14% To 5.25% (Dry Basis)

• NOx Increased From 0.405 To 0.413 lb/MBtu• Flyash LOI Reduced From 6.0% to 3.2%• Improvements Realized With No Changes In

Fuel Flow, Total Airflow, Steam Flow Or Any Burner Settings

The Results Of Removing 2E Mill Were:

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COMBUSTION IMPROVEMENTS

• Additional Tuning Reduced NOxEmissions From 0.413 lb/MBtu To 0.372 lb/MBtu With Minimal Impact On CO (4ppmc to 90ppmc) At A Reduced Excess Oxygen Level (5.3% to 3.7%)

• ESP Performance Restored To Expected levels

• 2E Mill Fineness Was Found To Be 98.15% Passing 50 Mesh And 74.47% Passing 200 Mesh

The Results Of Removing 2E Mill Were:

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CONCLUSIONS

THE KEY POINTS OF THIS CASE HISTORY ARE:1. The Unsteadiness Of The Combustion Could Easily Be

Misinterpreted By Conventional, “Snapshot-Style” Extractive Coal Flow Sampling.

2. Real Time Coal Flow And Emissions Sampling Allows A Much Quicker And More Accurate Analysis Of Combustion Variability.

3. Real Time Pulverizer Fuel Distribution Data Can Be Monitored Over Time And Compared To The Unit’s DCS Data For Impact-Based Analysis Of Combustion, Emissions And Efficiency.

4. Real Time Gaseous Emissions Monitoring Allows The Effects Of System Changes To Be Readily Evaluated In Terms Of The Unit’s Combustion, Emissions And Efficiency.

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CONCLUSIONS (Continued)

5. The Performance Of Only One Pulverizer Can Have A Very Pronounced Impact On Combustion Uniformity And Equipment Performance.

6. The Combustion Impacts Were Reducing Unit Availability And Key Equipment Life.

7. These Combustion Impacts Were Quickly And Accurately Identified Using The FERCo Proprietary Real Time Combustion Diagnostic Technologies.

8. These Same Diagnostic Technologies Were Used To Make Corrections To Key Operating Parameters, Which Were Proven To Improve The Unit’s Combustion And Reduce The Associated Impacts On Key Equipment Performance.

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ACKNOWLEDGEMENTS

• Doug Eakle And The Entire Staff At The Harrison Generating Station

ACHIEVING UNIFORM COMBUSTION USING REAL …ferco.com/Files/MP220-Power-Gen2005.pdf · achieving...

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