System integration and performance analysis of solid oxide fuel cell-inverted gas turbine hybrid system

Abstract

Solid oxide fuel cell systems often face significant challenges in recovering high-quality exhaust heat and require carbon capture when utilizing carbon-based fuels. In this study, we integrate solid oxide fuel cell with an inverted gas turbine to effectively recover exhaust heat and achieve efficient carbon capture through oxy-fuel combustion in the afterburner. To address the issue of excessively high turbine inlet temperatures caused by oxy-fuel combustion, this paper proposes an innovative approach involving steam or carbon dioxide injection to regulate combustion temperatures. Using rigorous theoretical analysis and process modeling, multiple hybrid system configurations are developed and assessed for thermal integration through pinch point analysis. Energy and exergy analyses are employed to compare system performance and investigate the impact of the fuel utilization factor. The results indicate that steam/CO₂ injection effectively controls combustion temperatures, enhances energy recovery, and significantly increases waste heat recovery capacity. Notably, the oxy-fuel combustion system achieves exceptional performance, with a peak gross efficiency of 75.54 %, an output power of 185.18 kW, and an exergy efficiency of 63.52 % at a fuel utilization factor of 0.85.