Combustion characteristics of lignite-fired oxy-fuel flames
Artikel i vetenskaplig tidskrift, 2009

This experimental work describes the combustion characteristics of lignite-fired oxy-fuel flames, in terms of temperature distribution, gas composition (O2, CO2, CO, total hydrocarbon concentration and NO) and ignition behaviour. The aim is to evaluate the flame structure of three oxy-fuel cases (obtained by changing the flue gas recycle rate) including a comparison with an air-fired reference case. Measurements were performed in Chalmers 100 kW test unit, which facilitates oxy-fuel combustion under flue gas recycling conditions. Temperature, O2 and CO concentration profiles and images of the flames indicate that earlier ignition and more intense combustion with higher peak temperatures follow from reduction of the recycle rate during oxy-fuel operation. This is mostly due to higher O2 concentration in the feed gas, reduced cooling from the recycled flue gas, and change in flow patterns between the cases. The air case and the oxy-fuel case with the highest recycle rate were most sensitive to changes in overall stoichiometry. Despite significant differences in local CO concentration between the cases, the stack concentrations of CO are comparable. Hence, limiting CO emissions from oxy-fuel combustion is not more challenging than during air-firing. The NO emission, as shown previously, was significantly reduced by flue gas recycling.

O2/CO2

Combustion

Oxy-fuel

Författare

Stefan Hjärtstam

Chalmers, Energi och miljö, Energiteknik

Klas Andersson

Chalmers, Energi och miljö, Energiteknik

Filip Johnsson

Chalmers, Energi och miljö, Energiteknik

Bo G Leckner

Chalmers, Energi och miljö, Energiteknik

Fuel

0016-2361 (ISSN)

Vol. 88 2216-2224

Ämneskategorier

Annan kemi

Kemi

DOI

10.1016/j.fuel.2009.05.011