New weighted-sum-of-gray-gases model for typical pressurized oxy-fuel conditions

Abstract

Pressurized oxy-fuel combustion technology has received considerable attention due to its ability to improve the overall system efficiency and to control CO2 emissions. The characteristics of radiation heat transfer are significant for pressurized oxy-fuel gas mixture and different from those under atmospheric conditions. Therefore, to calculate the radiation characteristics of pressurized oxy-fuel gas mixture quickly and accurately, new weighted-sum-of-gray-gases (WSGG) model for pressurized oxy-fuel conditions was first presented in this paper, which was applied in 3 typical high pressure conditions: 5, 10, and 15 bar. The new WSGG model correlations were suitable for pressurized conditions with a molar ratio range of 0.125-2, temperature range of 400-2500 K, and path length range of 0.1-20 m. Calculations for a variety of typical pressurized oxy-fuel combustion cases showed that the new WSGG model can accurately predict the radiation characteristics and heat transfer characteristics of the gas mixtures compared with the SNB model benchmark. In addition, the application of the previous atmospheric WSGG models yielded non-ideal results under pressurized conditions. Consequently, the new model can provide efficient and accurate radiation heat transfer results for pressurized oxy-fuel conditions and can be used to design pressurized oxy-fuel combustion furnaces or boilers.