Thermodynamic analysis of a coal-based combined cycle power plant

A thermodynamic analysis of a combined cycle power plant using pressurized circulating fluidized beds for partial gasification and combustion of coal has been made on the basis of both first law and second law. The Redlich-Kwong equation of state is used for evaluation of properties of air at high pressures in the topping gas turbine plant. A dual pressure steam cycle is considered in the bottoming plant for reducing irreversibility in heat transfer from gas to water and steam. The effects of pressure ratio and peak cycle temperature ratio of the gas cycle and the lower saturation pressure of the steam cycle on the overal performance of the combined plant have been evaluated.