Thermodynamic and Economic Analysis of Oxy-Fuel-Integrated Coal Partial Gasification Combined Cycle

A novel partial gasification combined cycle (PGCC) system integrating coal partial gasification, oxy-fuel combustion, combined cycle, and CO₂ separation is proposed. The coal-CO₂ partial gasification technology is introduced in the coal gasification unit, and the oxy-fuel combustion technology is employed in the char combustion unit and gas turbine (GT) unit. The thermodynamic and economic analysis of the proposed system is carried out, showing that both energy and exergy efficiency have an increasing/decreasing tendency when the recycled flue gas (RFG) ratio of char combustion and GT increase. When the RFG ratios of char combustion and GT are 0.43 and 0.34, energy and exergy efficiencies reach maximum values of 48.18 and 45.11%, respectively. The energy efficiency of the PGCC-Oxy system is higher than that of the integrated gasification combined cycle (IGCC)-Oxy system by approximately 3%. It can be concluded from the economic analysis that the total investment on the PGCC-Oxy system is 3272.71 million RMB, and the internal rate of return (IRR) and payback time is 8.07% and 12.38 years, respectively.