New WSGG model for gas mixtures of H2O, CO2, and CO in typical coal gasifier conditions

Abstract

This study develops a new weighted-sum-of-gray-gases (WSGG) model for the radiative characteristics of CO, H2O, and CO2 mixtures in pulverized coal gasification plants under a typical high pressure (45 atm). This is significant for prediction of radiative heat transfer in computational fluid dynamic (CFD) calculation. The new high-pressure WSGG model and its parameters are based on the statistical narrow band (SNB) model of EM2C Laboratory. The new model applies to the temperature range of 500–3000 K and the path length range of 0.1–20 m. Moreover, the model can calculate the radiation characteristics of gas mixtures under different partial pressures of three gases. Therefore, the new model can be applied to the radiation transfer in pulverized coal gasification under specific high pressure. The results of one-dimensional cases show that the new model can well predict the radiative heat transfer process of gas mixtures. The error of radiation heat flux is less than 5.38%, and the radiation source term error is less than 0.67%, while the accuracy of the traditional WSGG model is very low under gasification conditions, and the error is more than 25% compared with the benchmark. When the new model is embedded into the CFD simulation of a high-pressure gasifier, the maximum temperature difference between the new and traditional models is up to 300 K, while the calculated absorption coefficient and radiation source term of gas mixtures are noticeably different. In conclusion, compared with the traditional model, the new WSGG model has higher accuracy for calculating gas radiation heat transfer under the condition of coal gasification. This paper also provides the parameters of the new model, which can be used in the CFD engineering simulation of coal gasification plants.