Nitrogen oxide reduction by staged combustion of biomass gas in gas turbines: A modeling study of the effect of mixing

Edgardo G. Coda Zabetta, Pia Kilpinen, Mikko Hupa, Jukka Leppälahti, Krister Ståhl, Mike Cannon, Jorma Nieminen

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

1 Citation (Scopus)

Abstract

Detailed chemical kinetic modeling has been used to study the reduction of nitrogen oxides at gas turbine (GT) combustor conditions. A gas from gasification of wood with air has been used as the fuel. An air-staged combustion technique has been adapted.

In our previous study a simple plug flow model was used to study the effects of pressure and temperature among others process variables. The air-fuel mixing was assumed perfect and instantaneous. Results showed the NOx reduction mainly affected by both pressure and temperature.

The aim of the present work is to establish the effect of air-fuel mixing delay on NOx predictions and to extrapolate indications options for GT. To model the mixing delay, a varying number of air sub-streams are mixed with the fuel gas during different time periods. Alternatively, a combination of a perfectly mixed zone followed by a plug flow zone is illustrated.

Results by any air-fuel mixing model show similar affect of process variables on NOx reduction. When a mixing delay is assumed instead of the instantaneous mixing the NOx reduction is enhanced, and only with delayed mixing NOx are affected by CH4.

Lower temperature and higher pressure in the GT-combustor can enhance the NOx reduction. Also air staging is an effective option: a 3 stages combustor designed for low mixing speed appear competitive compared to more complicate combustors. The fewer hydrocarbons in the gasification gas the high NOx reduction.
Original languageEnglish
Title of host publicationASME 1999 International Gas Turbine and Aeroengine Congress and Exhibition
Subtitle of host publicationCoal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations
PublisherAmerican Society of Mechanical Engineers (ASME)
Number of pages6
Volume2
ISBN (Print)978-0-7918-7859-0
DOIs
Publication statusPublished - 1999
MoE publication typeA4 Article in a conference publication
Event44th ASME Gas Turbine and Aeroengine Technical Congress, Exposition and Users Symposium - Indianapolis, United States
Duration: 7 Jun 199910 Jun 1999

Conference

Conference44th ASME Gas Turbine and Aeroengine Technical Congress, Exposition and Users Symposium
Country/TerritoryUnited States
CityIndianapolis
Period7/06/9910/06/99

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