CFD Modeling of Utility Boiler Components at ALSTOM Power ...acerc.byu.edu/News/Conference/2004/Presentations/Galen...SCR - Ammonia Injection Grid Normalized mole fraction ratio: NH

Feb. 13, 2004Feb. 13, 2004

CFD Modeling of Utility Boiler Components at

ALSTOM Power Inc.Galen Richards

2-2-2004 Power Plant Laboratories

CFD at ALSTOM Power Inc.

Power Plant Laboratories (Windsor, CT)– 6 Engineers - full time CFD– 4 Engineers - part time CFD– Mainly use FLUENT– Also use CFX, Aiolos– Product development / problem solving for the Utility

Boiler business– Chemical process industry

2-2-2004 Power Plant Laboratories

PPL CFD Examples - Burners

Wall-Fired Coal Burner

LNCFS - P2™ Coal Nozzle

2-2-2004 Power Plant Laboratories

PPL CFD Examples - Boilers

HRSGStokerPC Boiler

2-2-2004 Power Plant Laboratories

PPL CFD Examples -Gas Turbine Combustors

2-2-2004 Power Plant Laboratories

Steam Drum Internals

2-2-2004 Power Plant Laboratories

PPL CFD Examples -Steam Drum Internals

Velocity Water m/s

4 Vanes 12 Vanes

2-2-2004 Power Plant Laboratories

Pulverizers

2-2-2004 Power Plant Laboratories

Pulverizer - Classifier Design

Static Classifiers Dynamic Classifiers

2-2-2004 Power Plant Laboratories

Pulverizer - Exhauster Design

Geometry Particle Concentration

2-2-2004 Power Plant Laboratories

Pulverizer - Exhauster Design

Predicted Errosion Patterns

2-2-2004 Power Plant Laboratories

Oil-Fired Utility Boiler

2-2-2004 Power Plant Laboratories

Oil Burner - Impact of Tilt

Windbox

Aux Air Nozzles20o Up Tilt

Fuel Air Nozzle 20o Up Tilt

2-2-2004 Power Plant Laboratories

Oil-Fired Boiler

Particle Trajectories Gas Temperature

2-2-2004 Power Plant Laboratories

Natural Gas-Fired Utility Boiler

2-2-2004 Power Plant Laboratories

Gas-Fired Boiler: Description

MCR 700 MWNatural gas fuelTangential firing system5 burner elevations30% flue gas recirculation (FGR)FGR with combustion air 12% separated overfire air (SOFA)50 ppm NOx

2-2-2004 Power Plant Laboratories

Gas Fired Boiler

Objective: Low cost solution for NOx of 15 ppm

NOx reduction strategies– Increased FGR– Steam or water injection– SOFA quantity and location– Burners out of service– Decreased load

2-2-2004 Power Plant Laboratories

Gas-Fired Boiler: Geometry

Windbox

SOFA

DivisionPanels

Economizer

Reheater

SH PendantSH Platen

Outlet

2-2-2004 Power Plant Laboratories

Gas-Fired Boiler: Geometry

Gas Inlet

Oil Air Inlet

Gas InletCombustionAir Inlet

Gas Inlet

Oil Air Inlet

Gas Inlet

2-2-2004 Power Plant Laboratories

Gas-Fired Boiler: Baseline

Temperature Oxygen NOx

2-2-2004 Power Plant Laboratories

Gas-Fired Boiler: NOx vs FGR

0

10

20

30

40

50

60

25 30 35 40 45 50% FGR

NO

x [p

pm-d

ry, c

or.]

NOx-Predicted

NOx-Measured

2-2-2004 Power Plant Laboratories

Gas-Fired Boiler: Conclusions

NOx emissions of 15 ppmachievable – Increase FGR to 45%– Inject 60,000 lb/hr of steam or

water through oil guns– or reduction to 950 ºF SH – Add independent yaw control

on SOFA tips to tune for CO

100 micron water droplets

2-2-2004 Power Plant Laboratories

SCR Design Issues– Flow Distribution– Temperature Distribution– System Pressure Drop– Particle Collection

2-2-2004 Power Plant Laboratories

SCR Design

TurningVanes

Mixer

AIG EconomizerOutlet

Catalyst

2-2-2004 Power Plant Laboratories

SCR - Velocity Distribution

Velocity ft/s

2-2-2004 Power Plant Laboratories

SCR - Measured NOx Profile

NOx, ppm

A - Side

B - Side

2-2-2004 Power Plant Laboratories

SCR - Ammonia Injection Grid

2-2-2004 Power Plant Laboratories

SCR - Ammonia Injection GridNormalizedmole fractionratio: NH3/NO

2-2-2004 Power Plant Laboratories

SCR - Vane Design

Suggested Vane Installation

Max velocityat corner ~ 130 fps

Velocity at cornerreduced to ~ 80 fps

No Vanes in SCR Outlet

2-2-2004 Power Plant Laboratories

SCR - Particle Collection

50 microns 250 microns

2-2-2004 Power Plant Laboratories

SCR - Particle Collection

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 50 100 150 200 250 300 350 400 450 500

Low Load - Flyash

High Load- Flyash

Col

lect

ed in

Hop

pers

(%)

Flyash Diameter - microns

2-2-2004 Power Plant Laboratories

SCR - Duct Metal Temperature

Diverging Section(includes spreader vanes)

Skin

Tem

pera

ture

(oR

)

SCR Inlet Duct

AIG Lances

Economizer Bypasses

2-2-2004 Power Plant Laboratories

Conclusions

CFD is a valuable design tool for a wide range of power generation applications

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