A novel dual-stage intercooled and recuperative gas turbine system integrated with transcritical organic Rankine cycle: System modeling, energy and exergy analyses

Abstract

Gas-fired power generation, characterized by high efficiency, low carbon emissions, and flexibility, contributes significantly to the global energy transition. In the present work, a novel dual-stage intercooled and recuperative gas turbine system integrated with transcritical organic Rankine cycle (dICR-GT-tORC) was proposed. System modeling was carried out based on Thermoflex software for different configurations to evaluate the energetic and exergetic performances. It was found that the dICR-GT-tORC exhibited improved thermodynamic performance compared to the gas turbine simple cycle and dICR-GT system, with the system net energy efficiency/exergy efficiency/specific work increasing from 43.88%/41.80%/567 kJ·kgair−1 and 57.21%/54.49%/684 kJ·kgair−1 to 62.48%/59.52%/745 kJ·kgair−1, respectively. An energy utilization diagram analysis revealed that the energy cascade utilization was achieved by coupling a bottoming tORC to fully utilize the waste heat from intercoolers and the exhaust gas. Furthermore, the dICR-GT-tORC demonstrated enhanced environmental performance, reducing the CO2 emission rate by a maximum value of 29.8%. Additionally, the impacts of key parameters, including the organic working fluid selection, the minimum temperature difference at the pinch point of recuperators and the terminal exhaust gas temperature on the system performance were investigated. It was indicated that the proposed system could be applicable in various practical scenarios from thermodynamic and environmental perspectives.