Comparison of effects on heat transfer and burnout under wet and dry recycle oxyfuel combustion conditions

Abstract

In this study, the effect of using both wet and dry recycled flue gases on oxyfuel combustion has been investigated using an International Flame Research Foundation (IFRF) burner installed on a 0·5 MWt combustion test facility firing Russian coal and Russian coal/biomass blend under wet and dry recycle conditions. Radiative and convective heat transfer characteristics and burnout measurements were the primary focus of the work. Recycle ratios were varied between 65 and 75%. The peak radiative heat flux decreases with increasing recycle ratio under both wet and dry recycle conditions for both the parent coal and the coal/biomass blend. The opposite trend is observed with the convective heat flux. The peak radiative heat fluxes are higher and the convective heat fluxes are lower for the dry recycle compared to the wet recycle. Low residual carbon in ash levels is measured with oxyfuel under both wet and dry recycle ratios.