Radiation intensity of lignite-fired oxy-fuel flames

Journal Article · Wed Oct 15 04:00:00 EDT 2008 · Experimental Thermal and Fluid Science

DOI:https://doi.org/10.1016/J.EXPTHERMFLUSCI.2008.07.010· OSTI ID:21116087

Andersson, Klas; Johansson, Robert; Hjaertstam, Stefan; Johnsson, Filip; Leckner, Bo ^[1]

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1. Department of Energy and Environment, Division of Energy Technology, Chalmers University of Technology, SE - 412 96 Goeteborg (Sweden)

The radiative heat transfer in oxy-fuel flames is compared to corresponding conditions in air-fuel flames during combustion of lignite in the Chalmers 100 kW oxy-fuel test facility. In the oxy-fuel cases the flue-gas recycle rate was varied, so that, in principle, the same stoichiometry was kept in all cases, whereas the oxygen fraction in the recycled flue-gas mixture ranged from 25 to 29 vol.%. Radial profiles of gas concentration, temperature and total radiation intensity were measured in the furnace. The temperature, and thereby the total radiation intensity of the oxy-fuel flames, increases with decreasing flue-gas recycle rate. The ratio of gas and total radiation intensities increases under oxy-fuel conditions compared to air-firing. However, when radiation overlap between gas and particles is considered the ratios for air-firing and oxy-fuel conditions become more similar, since the gas-particle overlap is increased in the CO{sub 2}-rich atmosphere. A large fraction of the radiation in these lignite flames is emitted by particles whose radiation was not significantly influenced by oxy-fuel operation. Therefore, an increment of gas radiation due to higher CO{sub 2} concentration is not evident because of the background of particle radiation, and, the total radiation intensities are similar during oxy-fuel and air-fuel operation as long as the temperature distributions are similar. (author)

• OSTI ID: 21116087
• Journal Information: Experimental Thermal and Fluid Science, Journal Name: Experimental Thermal and Fluid Science Journal Issue: 1 Vol. 33; ISSN 0894-1777; ISSN ETFSEO
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
AIR
CARBON DIOXIDE
COMBUSTION
COMBUSTION HEAT
CO{sub 2} reduction
FLAMES
FLUE GAS
Gas radiation
LIGNITE
MIXTURES
OXYFUEL COMBUSTION PROCESS
OXYGEN
PARTICLES
Particle radiation
RADIANT HEAT TRANSFER
STOICHIOMETRY
TEMPERATURE DISTRIBUTION