Integrated Characteristics of Air Separation Unit Scheme in Integrated Gasification Combined Cycle System

The integrated characteristics of air separation unit(ASU) in integrated gasification combined cycle(IGCC) were analyzed.The results show that increase of air compressor pressure ratio made the air separation process difficult,and caused increase of air pressure potential energy consumption in air distillation separation process.While increased pressure ratio was beneficial to reduce the power consumption for oxygen production and increase the power generation efficiency of IGCC.Comprehensively considering the NOx emission and power consumption for oxygen production,0.85 oxygen purity of ASU was recommended for IGCC system.The integrated characteristics of ASU and gas turbine showed that power generation efficiency of IGCC system increased first and then reduced with ASU integration degree increasing,and the highest power generation efficiency of IGCC could be achieved at the integration degree 0.80.Furthermore,compared with independent ASU scheme,IGCC system with the integrated ASU scheme hold potential to improve power generation efficiency,considering sensible heat of air drawn from gas turbine compressor could be exploited in the future.