CFD Simulation of an Oxy-fuel Demonstration Power Plant with Application of a WSGG radiation model

Abstract

The oxy-fuel process is a promising technology for capturing carbon dioxide emitted by coal-fired power plants. Due to the combustion of coal with pure oxygen and recycled flue gas, the concentrations of carbon dioxide and water vapor in the flue gas of the power plant boiler are higher than in the air-fired process. Both species show strong absorption and emission characteristics in the infrared wavenumber region providing enhanced radiative heat transfer to the evaporator tubes along the furnace walls. To accurately predict thermal radiation, the non-gray behavior of gas radiation has to be accounted for. Efficient non-gray radiation models have been developed to be applied to numerical simulations of oxy-fuel furnaces. One approach is the application of new weighted sum of grey gases model (WSGGM) to 3D-CFD simulations. In this study, the simulation of a demonstration scale oxy-fuel power plant furnace is presented. Gas radiation is modelled with the WSGGM with a state of the art parameter set. The WSGGM formulation includes the molar ratio of H2O-CO2 mixtures. Therefore, it is suitable for the modeling of radiation under oxy-fuel conditions. The simulation results deliver information on the combustion process and the heat transfer inside the boiler, especially in the evaporator section.