Combustion Optimization for Coal-Fired Boilers

2nd U.S.-China NOx WorkshopDalian, ChinaAugust 2005

James TobinNeil Widmer

GE Energy

The problem …

3GE Energy

August 2005

Poor combustion result in many performance issues.

Reduced Througput (Load)

High Metal Temperatures

Increased FEGT(Furnace Exit Gas Temperature)

Reduced Efficiency

~CoalSupply

CoalCrusher

Mill

CoalSilos Boiler

AirHeater

Stack

IDFan

FDFan Turbine Generator

Local Fouling

Increased Steam Spray

Local Slagging

Local Hot Spots

Increased Excess O2

High COHigh CO

Combustion profile as monitored by Spatial Sensors

Economizer O2 Imbalance

Local Corrosion

High Carbon in Ash, eg. LOI(Loss on Ignition)

High NOx

4GE Energy

August 2005

The major lost opportunities result from poor combustion.Fleet-wide lost opportunity cost can be over $80 MM per year.

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Boiler Fleet

Ann

ual L

oss

Opp

ortu

nity

Con

trib

utio

ns Condensate System

Opacity

Controls Chemistry

Seasonal Derate

Feedwater System

Slag & Ash Removal

PRB Derate

Air Supply

Fuel Quality

Mill/Feeders

Turbine

Tube Leaks

Contributing Factors:

5GE Energy

August 2005

Improved burner operation drives performance gains.

Fuel SavingsCo

mfo

rtZo

ne

Initial A/F Initial A/F σσ

FEGT

Improved Improved A/F A/F σσ

High CO Burners Limit Performance

Emissions CreditsAvailability & Peak Power

Output (Throughput)

Solutions …

7GE Energy

August 2005

Zonal™ combustion control system

Combustion (O2/CO) Monitors

Output

NOx

Availability

Burner Airflow

Controls

Combustion Tuning Controls

Efficiency

Combustion Diagnostic

Zonal Fuel and Air Optimization

Burner Adjustments 1

2

3

object

Burner Coal Flow Controls

8GE Energy

August 2005

Combustion Sensors

Combustion Tuning Model

Burner Airflow Controls

Coal Flow Sensors

Coal Flow Dampers

Components …

Zonal™ Combustion Controls

9GE Energy

August 2005

Zonal™ combustion control system … how fuel & air controls work together.

Zonal CO Trim - fine controls for combustion balancing :> Trim furnace zonal air/fuel

ratios based on sensor grid– Balance CO– Reduce hot spots– Reduce delayed

combustion– Maintain burner flame– Reduce LOI– Reduce excess O2

Zonal Fuel Trim - coarse controls for combustion shaping :> Optimize wall-burner firing

– Reduce impingement> Reshape tangential fireball

– Centered and round > Tune furnace fuel

distribution – Balance economizer O2

– Divert heat loading from peak FEGT & slag regions

10GE Energy

August 2005

Fuel control can reduce temperature and CO zones … the precursors to slag.

AfterBefore

CO Profile

Max = 2088 Max = 2023

Gas Temp. Profile

11GE Energy

August 2005

Automatic Fuel Trim controls are successful at tightening distribution.

-25%-20%-15%-10%

-5%0%5%

10%15%

Burner Coal Flow Bias

As-Found Manual Automatic

Coal Distribution

Burner C1Burner C2Burner C3Burner C4Burner C5

First Demonstration August 2003

12GE Energy

August 2005

Balanced and optimized coal flow distribution reduced peak FEGT 60°F.

2375

2400

2425

2450

2475

2500

2525

Furn

ace

Exit

Gas

Te

mpe

ratu

re (d

eg. F

)

Baseline Balanced OptimizedCoal Distribution

Ash Fusion Point

Peak FEGT Reduction

10 MW Capacity Increase

13GE Energy

August 2005

20°F Peak FEGT limited boiler capacity approximately 10MW.

2,150

2,200

2,250

2,300

2,350

2,400

2,450

2,500

2,550

2,600

2,650

2,700

220 240 260 280 300 320 340 360 380 400

Load, MWg

Furn

ace

Exit

Gas

Tem

pera

ture

, deg

F

FEGT West

FEGT East

FEGT Average

Turbine CapacityBoiler Limit

14GE Energy

August 2005

Zonal™ combustion monitoring system

Interface Display

Modeling (upgrade)

Flow and Control Panel

Sensor Array

15GE Energy

August 2005

Zonal™ combustion model-based control system.

Combustion Trim ModelMonitoring & Control Interface

16GE Energy

August 2005

Zonal™ combustion tuning system demonstration.

Burner Tuning

Combustion Sensors

Boiler Model

Initial CO

Tuned CO

Tuninem

o

g D

17GE Energy

August 2005

0100200300400500600700800900

1000

CO

Lev

el, p

pm

CO

#11

CO

#6

CO

#12

CO

#7

CO

#14

CO

#13

CO

#1

CO

#9

CO

#8

CO

#10

CO

#4

CO

#15

CO

#5

CO

#2

CO

#3

Combustion Sensors

Initial Tuned

0

0.5

1

1.5

2

2.5

3

3.5

Fly-

Ash

LO

I, %

West Middle East

Flue Gas Duct

Initial Tuned

Systematic tuning balanced CO and fly-ash LOI … synergistic with Hg control.

18GE Energy

August 2005

Zonal™ combustion control system features:> Faster tuning experience> One system for managing Zonal™ combustion> Improves quality through systematic methods> Advises burner adjustments> Stores preferred burner setting by operating

mode> Diagnoses combustion performance

Benefits …

20GE Energy

August 2005

Combustion Optimization – Case StudySunflower Electric 380 MW BoilerScope:> GE coal flow monitors & control> GE combustion sensors> GE boiler tuning services> GE control software

System Benefits:> Reduced peak FEGT 60°F

– Eliminated barrier to increasing output 10 MW worth $1M/yr

> Reduced high CO and temperature zones

– Avoid future slag outage 1 weeks worth ~ $2.5M/yr

> Reduced NOx and Heat Rate

Furnace Combustion Balancing

Burner Fuel/Air FlowSensors & Auto-Control

Coal Flow

Sensor

Coal Damper

Furnace Combustion

Sensor Arrays

CO Sensor

Burner Air Control

21GE Energy

August 2005

Zonal™ combustion controls benefits:

Reduce average and peak FEGTReduce fuel rich (CO) zonesReduce corrosionReduce slaggingReduce LOIReduced NOx

22GE Energy

August 2005

Good combustion provides significant benefits.

0500

1,0001,5002,0002,500

100 300 500 700 900

Boiler Load, MWe

Ann

ual B

enef

its, k

$/yr

Emissions Heat RatePeak Power Availability

Improvements :> Excess O2: 0.5% reduction> Emissions (NOx): 15% reduction> Heat Rate: 0.4% improvement> Peak Power: 2.3% increase> Availability: 1 week avoided

outage

Economic assumptions provided in notes

Economic benefits are site-specific. Your plants benefits may vary.