Optimization of a Combined Cycle for Power Generation Integrated with Biomass Gasification

A new combined system based on a biomass gasifier, gas turbine, S-CO2 cycle and an organic Rankin cycle for power generation is proposed and assessed thermodynamically. Exergy analysis is conducted to determine the irreversibilities in system components. In addition, an environmental impact assessment is performed for each of the three types of plants in the combined system. To understand the system performance more comprehensively, a parametric study is performed to investigate the effect of several important design parameters on the net power output and exergy efficiency of the system. The system performance is optimized and the optimum design parameters were determined. The results demonstrate that an increase of 300oC in the turbine inlet temperature results in 7.52% and 23.45% increases for the exergy efficiency and net power output, respectively. This temperature increase also brings about an increase of 12.98% and a nearly constant pressure ratio of the air compressor and the S-CO2 compressor in optimum working condition. In addition, compared to the gas turbine, the exergy efficiency of the combined system is 10.07% higher and the CO2 emission of the combined system is 25.82% lower.