Authors: Sanghyun Park Jungeun A Kim Changkook Ryu Won Yang Young Ju Kim Sangil Seo
Publish Date: 2012/05/20
Volume: 26, Issue: 5, Pages: 1633-1641
Abstract
Oxyfuel combustion exhibits combustion and heat transfer characteristics different from airfuel combustion due to high concentrations of CO2 and H2O This study evaluated the effect of gas and particle emissions on radiative heat transfer in oxyfuel combustion of coal For a hexahedral furnace prescribed gas compositions based on combustion calculation were used to simplify the combustion reactions The values of radiative heat fluxes qrad were compared for different combustion modes flue gas recirculation FGR methods particle concentrations furnace sizes and O2 concentrations in the oxidizer The radiation was calculated by the discrete ordinate method with gaseous emission predicted by the weighted sum of gray gases models WSGGMs The results showed that employing an optimized WSGGM is essential for the accurate prediction of qrad in oxyfuel combustion for gaseous fuels The conventional WSGGM showed large errors for larger furnace volumes or under dry FGR conditions With higher particle concentrations such as in pulverized coal combustion however qrad was dominated by emission of particles The effect of gas emissivity was not critical in the furnace with a mean beam length of 83m Oxyfuel combustion with wet FGR had higher qrad than dry FGR The O2 concentration in the oxidizer was a key parameter for oxyfuel combustion since increasing its value linearly increased qradChangkook Ryu is an associate professor in School of Mechanical Engineering at Sungkyunkwan University Korea He received his PhD degree on Mechanical Engineering at Korea Advanced Institute of Science and Technology KAIST in 2001 He was a research associate in Department of Chemical and Process Engineering at University of Sheffield UK from 2002 to 2007 His research interests include energy conversion of biomass coal and other fuels by combustion gasification and pyrolysis
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