An efficient methanol pre-reforming gas turbine combined cycle with integration of mid-temperature energy upgradation and CO2 recovery: Thermodynamic and economic analysis

Abstract

An innovative design has been developed to optimize the performance of the gas turbine combined cycle (GTCC) by integration with a decarbonized methanol steam reforming (MSR-deCO2) system based on the principle of the cascade utilization of chemical and thermal exergy. In the integrated system, the primary fuel is reformed with the steam extracted from GTCC and decarbonized before combustion. The reforming process leads to a significant reduction of exergy loss in the combustor. Introducing methanol as a viable turbine fuel presents an opportunity for recuperating mid-temperature heat as chemical energy through endothermic MSR and redeeming it as high-grade thermal energy in the combustor. By such incorporation, the power generation of the mid-temperature heat in the bottoming cycle is significantly enhanced, and most of the CO2 is removed as the liquid phase. Based on a 530 MW GTCC plant, thermodynamic analysis reveals a 4.6% energy efficiency increase, a 4.3% exergy efficiency boost, and an 82.2% CO2 recovery with a 0.354 MJ/kgCO2 energy penalty. The proposed design yields 454.4 M$ more profit than the reference power plant throughout its lifespan. Additionally, sensitivity analysis indicates optimal conditions for MSR at approximately 250 °C, a 1:1 water-to-methanol ratio, and a higher reaction pressure preference.