Techno-economic and environmental optimization of a combined regenerated gas turbine and supercritical CO2 cycle based on methane and hydrogen mixture as fuel for environmental remediation

Abstract

Achieving power generation systems with high efficiency and low emission of environmental pollutants is one of the requirements of a sustainable environment. In this study, a hybrid power generation system based on gas turbine (GT) with regenerator configuration is introduced. A supercritical carbon dioxide (sCO2) cycle is used to recover the waste heat from GT exhaust gases. In order to reduce the emission of environmental pollutants, the combination of hydrogen and methane is used as GT fuel. In order to investigate the effect of using hydrogen in the fuel composition, the fraction of hydrogen is changed between 0 and 50% and its effect on performance, environmental, and economic factors is investigated. Also, the effect of design parameters such as compressor pressure ratio (CPR) and turbine inlet temperature (TIT) of GT and sCO2 cycles on exergy efficiency, total cost rate (TCR), and normalized pollutants emission index are investigated. Then, by performing a bi-objective optimization process with the aim of achieving maximum exergy efficiency and minimum TCR, the optimal operating point is extracted. At the optimal operating point, exergy efficiency is 44% and TCR is 6 dollars/second.