METHANE de-NOX® (MdN) Reburn Process for Wood Waste-Fired Stoker Boilers

Continuation Projects: -Utilization of NCGs as Reburn Fuel in Wood Waste – Fired Stoker Boilers

-Advanced METHANE de-NOX for Wood Waste-Fired Stoker Boilers

PI: Stan Wohadlo, Joseph Rabovitser R&D Partners: Fluent Corp, Reaction Engineering International Industry Partners: Boise Paper Solutions, EnergySystems Associates, Detroit Stoker Corporation Sponsors: DOE – Industrial Technologies Program, Boise, GRI, Sustaining Membership Program (SMP)

This presentation was prepared with the support of the U.S. Department of Energy, under Award No. DE-FC26-00NT40752. However, any opinions, finding, conclusions, or recommendations expressed herein are those of the authors and do not necessarily reflect the views of DOE.

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MdN Performance Goals for the FPI

� Reduce both operating costs and airemissions through advanced combustion-based technology in Hog Fuel Boilers � Increase utilization of wood wastes as boiler fuel � Improve boiler operability, reliability, & efficiency � Improve boiler environmental performance

� Provide cost effective & efficient route for destruction/utilization waste gases

� Increase self-generated power capacity

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Outline

� Hog Fuel Boiler Challenges � Research Focus � Technology Description � Agenda 2020 projects � I. Falls Project Results Base Project � DeRidder Project Status Continuation Project � Port Hudson Optimization Studies Continuation Project � Commercial Design Packages

� MdN Development & Deployment Summary � Commercialization

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Hog Fuel Boiler Challenges

� Hog fuel issues � Stoker grate � Combustion air distribution � Fan capacities � Auxiliary burners � Waste gas combustion � Existing NOx, CO and particulate controls � Firing practices

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Research Focus� Strategic use of Natural Gas in combustion

process - more than just heating value

� Small natural gas inputs provide:� Combustion stabilization � Improved startup and load following � Stabilize burning of low/variable quality fuels

� Emissions reduction� NOx, CO, particulate

� Efficiency improvement� Improved carbon burnout� Reduced excess air

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Technology Description 3-stage Combustion for Stoker Boilers

� Injection of reburn fuel (preference is natural gas)/FGR near the grate for intense gas mixing

� Oxygen-deficient atmosphere above the grate to retard NOx formation

� More uniform furnace temperatures Overfire CombustibleAir Burnout Zone with higher average and lower peak

NO and temperatures) : x

Reburn Fuel NO Precursor � increased fuel drying above thex & FGR Reduction Zone grateBark & NO Formation x

Zone � improved bark/sludgeSludge combustion capacity

� Reduced fuel and ash piling on Undergrate air

Ash the grate � Injection of OFA at a higher furnace

elevation to improve burnout

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Implementation of the Technology 3-Fundamental Elements –Selection Flexible based on Client Objectives

MdN OFA

Bark &

Ash

MdN FGR

NG/FGR

Sludge

UGA

MdN Reburn Fuel Injection

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Technology Applications

Minnesota (MSW)z 60% NOx

reduction z 50% CO

reduction z +2% eff.

Japan (MSW) z 2 WTE plants z 50% NOx

reduction z 80% Dioxin

reduction

Virginia (Coal)z 240 MW - 8

boilersz 70% NOx

reduction z + 2% eff.

MN and LA (Bark and Sludge) z 225 - 250 Klb/h

bark/sludgeboilers

z 30 - 40% NOx reduction

z Up to +2% eff.

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Technology Development and Deployment Summary

Base Project � International Falls, MN demo completed, in continuous

service-HFB � Wallula, WA baseline testing completed-HFB � Port Hudson, LA in continuous full scale service-HFB Continuation Project � DeRidder, LA baseline testing completed-HFB

Commercialization � Discussion between ESA and a Mill owner underway with

potential of 4 commercial deployments of elements of MdN Technology, CFD modeling is in progress-HFB

� ESA retrofitted 18 additional coal-fired stoker boilers with elements of MdN technology, satisfying client objectives

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Agenda 2020 Projects - I Falls

� Increase firing of clarifier solids with high fuel-bound nitrogen content

� Increase boiler thermal efficiency through improved burnout and lower excess air

� Maintain NOx and CO emissions at or below permit limit

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I. Falls Boiler #2 Long-Term Results 1999 / 2000 Comparison

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

2.00

2.25

2.50

#2 Boiler 109 (tons)

NOx (tons)

1999 2000

343

176

3,100

7,000

339 287

BTU gas use Sludge burned Boiler Eff. %

Rat

io 1

999

vs. 2

000

82 83

� 52 tons less NOx emitted

� $770,000 savings reported after 1st year operation � 3900 tons less

sludge landfilled � 167 billion BTUs

less gas energy used

� 2001 - 248 billion BTUs less gas energy used

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Continuation Project – DeRidder

� Safe and effective disposal of LVHC and SOG

� Reduced auxiliary fuel (natural gas) use � Boiler efficiency improvement � NOx reduction up to 40%

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3-Stage Combustion with NCG/SOG as Reburn Fuel

Extension of basic technology Benefits:

� Provides an alternative to NCG/SOG injection in gasburners

� Removes need for gasburners during NCG/SOG

Ash

SOG

NOxZone

NOxNOx

LVHC

Overfire Air

NG/FGR

Woodwaste

Combustible Burnout Zone injection

and � Reduces rate of NOX formedPrecursor

Reduction Zone by ammonia in SOGcompared to current schemeFormation

� Reduces consumption ofnatural gas by up to 25%more than basic reburnUndergrate air process

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NCG/SOG Baseline Test Conclusions� Reburn plus improved bark and air

distribution can meet project objectives � NCG & SOG must be injected separately

� NCG & SOG flow & composition highlyvariable - natural gas/FGR injection system can compensate flow and fuel valuevariations

� Decoupling SOG from gas burners canreduce gas usage and ammonia conversionto NOx

� Reducing excess air will compensate foradded FGR flow in furnace

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DeRidder Project� In November of 2004, mill was acquired by a

new owner. The NCG/SOG technology demonstration work was placed on hold.

� Due to continued uncertainty at the mill, the field demonstration was canceled.

� Work was replaced with development of a MdN Commercial design report to serve as a resource for commercialization of the technology

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Port Hudson Optimization Study

Reburn System Design

� CFD model-based approach � Evaluate OFA and FGR use � Existing and/or new nozzles � Size, placement, flow conditions

� Compare effects on furnace conditions that influence NOx, CO and particulate

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Optimization StudyOxygen Contours - Baseline

Wi pt spouts

Mi

Upp

Fi j i l

ing

ndswe

Gas/FGR nozzles

d-level OFA

er-level OFA

nes Rein ect on nozz es

Gas Cofir burners

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Optimization StudyCO Contours – with MdN

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Optimization Study

� Based on findings from the study, changes were made to Port Hudson’s OFA and FGR arrangement

� Results for the optimized system were: � Additional NOx reduction of 30% � Improved CO burnout at lower excess air � Reduced co-firing gas consumption by 50%

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MdN Commercial-scale Design Report

� Created a commercial-scale design report to promote acceptance of technology in FPI

� Design package includes results from CFD modeling and engineering recommendations for construction of MdN systems for four types of woodwaste stoker boilers

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MdN Commercial-scale Design Report � Stoker boiler with a square furnace, traveling grate and

LVHC NCG injection through furnace rear wall � Stoker boiler with a rectangular furnace, stationary

pinhole grate, and no NCG � Stoker boiler with a rectangular furnace, traveling

rotograte, and HVLC NCG injection under the grate � Stoker boiler with a square furnace, vibrating hydrograte

(water-cooled), and LVHC NCG injected through furnace rear wall

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Project Summary� Work is essentially complete, draft final

report submitted

� GTI continues collaboration with ESA in promotion of technology on an as need basis. � Participated with ESA in a field evaluation of I Falls

stoker boiler in November 2005

� Technology license agreements in place with ESA and Takuma � ESA has installed 18 MdN coal-fired stoker systems

over the last two years 22

Energy Savings� In U.S pulp and paper mills, approximately

150 woodwaste-fired stoker boilers are estimated in operation. A typical boilerconfiguration has a thermal input of 300mmBtu/h (200 kpph steam) � With Mdn,overall thermal efficiency increases between

1 to 2%. � Potential energy savings per boiler is 4.5 mmBtu/h � Annual energy savings based on a 80% capacity factor

is 31,500 mmBtu/yr-unit � Based on a 25% reduction in natural gas consumption

(15% of heat input); a savings of $400,000 is estimatedper year (80% capacity factor)

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Other Benefits

� Emission reduction to 0.20 lb NOx/mmBtu is achievable. � Based on boiler uncontrolled emission of 0.275 lb

NOx/mmBtu, total emissions reduction equals about 80 tons of NOx/yr-unit (80% capacity factor) � Equivalent to removing about 1,300 cars from the road

yearly

� Increased steam production by 2 to 5%

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Commercialization

� Drivers � NOx environmental regulations � Cost of NOx emission credits � Capital Investment

� Main competition to MdN technology include improved combustion/OFA Systems and SNCR technology � SNCR is expensive to install and more expensive to

operate and maintain

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Commercialization� Considerations � Evaluate other reburn fuels candidates such as highly

reactive sawdust, syngas, other combustible waste streams

� Co-fired hog fuel boilers continue to offer a good opportunity for MdN technology

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Commercialization Plan

� Target Market � Natural gas co-fired Hog Fuel Boilers populating the

pulp and paper industry firing wood, woodwaste, biosolids and waste gases

� Heat input rates above 250 mmBtu/h � Location in Ozone Transport Region, California and

non-attainment regions in Texas (Houston/Dallas) � Based on estimates of bark-fired stokers in the

paper industry; there is an opportunity for 2 to 3 MdN retrofits per year during the next decade

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Commercialization Plan

� Technology Licensees

� Environmental Systems Associates (ESA), a limited liability corporation located in Pittsburgh PA. Licensed for coal and wood applications in the U.S.

� Takuma, licensed for MSW applications in Japan

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