Keywords: coal gasification, exergy efficiency, energy efficiency, integrated gasification combined cycle power plants, thermodynamic analysis, nitrogen supply, system performance, gas turbine cycle, pressure ratio, steam turbine inlet temperature
Thermodynamic analysis of an integrated gasification combined cycle power plant: effect of nitrogen supply on system performance
A comprehensive thermodynamic analysis of a conceptual integrated coal gasification combined cycle power plant is presented. Energy and exergy efficiencies and exergy destructions of each sub–unit are calculated. The effect of nitrogen, which is supplied from the Air Separation Unit (ASU) of the gasification unit to the combustion chamber of the gas turbine (GT) cycle, on system performance is parametrically studied. The energy efficiency of the system is found to be 41%, while the exergy efficiency for the integrated gasification combined cycle power plant is 37%. The results also demonstrate that the nitrogen supply enhances the system performance. Additional parametric studies are presented for various operating conditions: nitrogen supply ratio, pressure ratio, and steam turbine inlet temperatures.