Thermodynamic assessment of an integrated MILD oxyfuel combustion power plant

The paper presents the advantages of a new boiler solution for the supercritical power plant with CO₂ capture. The MILD oxyfuel combustion (MOFC) combines the advantages of MILD (moderate and intensive low-oxygen dilution) combustion and oxyfuel combustion for the purpose of an effective CO₂ capture from fossil fuel based power generation. MOFC application could increase the efficiency of the boiler, increase the purity of the CO₂ in flue gases and reduce energy consumption for the recirculation of CO₂. It affects the overall net energy efficiency penalty associated with the CO₂ capture in comparison to the oxyfuel combustion technology. Thermodynamic analysis of an integrated MOFC power plant with CO₂ capture are presented. The data concerning the new design of the boiler are obtained from CFD modelling. Two case studies are performed, and in each of them three configurations of supercritical power plant are modelled. First two are the reference power plants, including the conventional power plant without CO₂ capture and oxyfuel combustion power plant with CO₂ capture. The third case is the MOFC boiler application within the same power plant. The thermodynamic parameters are compared, and detailed study of energy efficiency penalty is presented. Based on the presented results it can be noticed that the application of the MOFC technology allows to increase the overall net energy efficiency by about 2% points. Additionally the usefulness of the proposed system approach (based on input-output analysis) for the energy analysis of complex energy systems have been proven.