A new WSGGM considering CO in oxy-fuel combustion: A theoretical calculation and numerical simulation application

Abstract

The HITEMP 2010 databases was employed in line by line (LBL) method to calculate an accurate total emissivity benchmark for oxy-fuel combustion atmosphere. This paper focuses on the effect of CO in the oxy-fuel gas mixture on the total emissivity. CO is significant in the primary combustion zone of boiler, generating from incomplete combustion and gasification reactions in oxy-fuel combustion mode. Based on the total emissivity benchmark from LBL, the new correlation coefficients for weighted sum of gray gases model (WSGGM) are fitted for mole fraction of CO from 0% to 45%, molar ratio of H2O to CO2 between 0.01 and 4, temperature range of 400 K–3000 K and path length varying from 0.01 m to 60 m. Radiative heat flux and radiative source term results from solving the radiation transfer equation (RTE) in one-dimensional slab system are used to evaluate the accuracy and effectiveness of new correlation coefficients for WSGGM. By comparing with the results from LBL and models in other literature, new correlation coefficients for WSGGM are validated no matter in non-isothermal and non-homogenous conditions considering CO in gas mixture. At last, the new correlation coefficients are implemented in the numerical simulation of oxy-natural gas furnace to show the effect of gas radiation model on the wall surface radiative heat flux.