2_application of nox emissions control technologies to achieve nox emission less than 200 mgnm3 on...

8/13/2019 2_Application of NOx Emissions Control Technologies to Achieve NOx Emission Less Than 200 MgNm3 on Coal

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Application of NOx Emissions Control

Technologies to Achieve NOxEmissions Less than 200 mg/Nm3 onCoal Fired Boilers

Mogens ChristensenDavid MoyedaRoy Payne

GE Energy

International DeNOx Symposium

Athens, Greece23 June 2005


2/15

2GE Energy

23 June 2005

Available NOx emissions control

technologies vary in performanceand cost

LNB OFA Reburning SNCR SCRNOx Control Technologies

Components Involved

Replace or Modify burners X

Staged Air Injection X X

Staged Fuel Injection X

Nitrogen Agent Injection X X

Catalyst Reactor X

Nominal NOx Reduction 30-50% 20-30% 50-60% 15-35% 80-90%


3/15

3GE Energy

23 June 2005

Technology layering is one solution

for EU LCPD compliance

Main Fuel

Air

Low-NOx BurnersOverfire Air

Reburn Fuel

SNCRCO

SensorsCombustionSensors

Fuel & AirControls


4/15

4GE Energy

23 June 2005

Layering of technologies can provide

significant reduction of NOx

0

200

400

600

800

1,000

1,200

Baseline LNB LNB &

OFA

LNB &

Reburn

LNB &

Reburn &

SNCR

NO

xEmissio

ns,mg/N

m3

~50%

~20%

~60% ~30%

Typical coal-fired boiler with wall-fired burner design


5/15

5GE Energy

23 June 2005

Reburning process consists of both

fuel and air stagingNOx generated in the

main combustion zonereacts with fuel fragmentsinjected into the reburn

zone, reducing it tomolecular nitrogen.

Overfire

Air

ReburnFuel

CH4 CH

CH + NO HCN

HCN + OH NH2

NH2 + NO N2

MainFuel

Air


6/15

6GE Energy

23 June 2005

Reburn zone stoichiometric ratio is

optimum around 0.9

0

100

200

300

400

500

600

700

0.6 0.7 0.8 0.9 1.0 1.1 1.2

Reburn Zone SR

ExhaustNOx,

ppm(

0%

O2)

Utah Coal

Colstrip Coal

Beulah Coal

Yallourn Coal

Propane

Primary NOx = 630 ppm

Primary SR = 1.1

Reburn Fuel


7/15

7GE Energy

23 June 2005

Selective non-catalytic reduction

consists of nitrogen agent injectionAt the proper temperature,

the SNCR agent (forexample, ammonia orurea) selectively reduces

NO to molecular nitrogen.

NH3 + OH NH2 + H2O

NH2 + NO H + OH + N2

H + OH H2O

SNCR

MainFuel

Air


8/15

8GE Energy

23 June 2005

Optimum gas temperature for SNCR

is around 1,800F (~1,000C)

0

20

40

60

80

100

800 900 1,000 1,100 1,200

Temperature, deg. C

(

NOx)Out/(NOx)In,%

Ammonia

Urea Solid

Urea Spray

(NO)In = 700 ppm

NSR = 2

Reagent


9/15

9GE Energy

23 June 2005

Opposed wall-fired boiler retrofit with

low-NOx burners and coal reburn

Overfire AirInjectors

Reburn Fuel

Injectors

Low-NOx

Burners

CombustionOptimization

Sensors

Plant: Green Station

Capacity: 120 MW x 2 Fuel: Bituminous coal

Integrated NOx Control

Solution:

Low-NOx Burners

Coal Reburn System

Combustion Sensors


10/15

10GE Energy

23 June 2005

Advanced models are applied to

ensure optimal performanceBoiler Model

LNB

Duct Model

Reburn & OFA

Jet Pathlines


11/15

11GE Energy

23 June 2005

Coal Reburn provides effective NOx

control with minimal boiler impacts

0

100

200

300

400

500

600

0 10 20 30

Reburn Fuel or OFA, %

NOxEmissions,mg/N

m3

LNB

OFA

Coal Reburn

Optimized

Coal Reburn

0

50

100

150

200

0 10 20 30

Reburn Fuel, %

CO

Emis

sions,ppm

0

5

10

15

20

FlyAs

hLOI,%

LOI

CO


12/15

12GE Energy

23 June 2005

Tangentially fired boiler retrofit with

low-NOx burners, reburn, & SNCR Plant: Somerset Station

Capacity: 120 MW Fuel: Bituminous coal

Integrated NOx Control

Solution:

Low-NOx Burners

Gas Reburn System

Urea Injection System

Overfire AirInjectors

Reburn Fuel

Injectors

Low-NOxBurners

SNCR System

(not shown)


13/15

13GE Energy

23 June 2005

Performance results with low-NOx

burners, Gas Reburn, & SNCR

0

100

200

300

400

500

600

700

0 10 20 30

Reburn Fuel or OFA, %

NOxEmissions,mg/N

m3

Baseline

OFA

Gas Reburn

GR + SNCR


14/15

14GE Energy

23 June 2005

Impacts of SOFA, Reburn, & SNCR

on NOx emissions

0

100

200

300

400

500

0.80 0.85 0.90 0.95 1.00

SR Below SOFA

NO

xEmissions,mg/N

m3

SOFA

Reburn, SR1 > 1.05

Reburn, SR1 < 1.050

100

200

300

400

0.80 0.85 0.90 0.95 1.00

Reburn Zone SR

NO

xEmissions,mg/N

m3

Reburn

Reburn + SNCR


15/15

15GE Energy

23 June 2005

Summary

Layering of combustion modificationtechnologies (low-NOx burners, overfire air,

Reburn), with SNCR trim, provides a cost-effective approach to NOx emissions control.

Reburning with either natural gas or coal is

effective for coal-fired boilers.

Layering of NOx emissions control

technologies can permit both short term andlong term EU LCPD compliance

2_application of nox emissions control technologies to achieve nox emission less than 200 mgnm3 on...

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