Novel CO2 capture pathway for SOFC-based distributed energy systems: Collaborative water-gas-shift membrane reactor and oxy-fuel combustion technologies

Conventional carbon capture technologies utilized in SOFC-based distributed energy systems significantly elevate energy consumption and costs. To address the challenges, this study presents a concept of collaborative water-gas-shift membrane reactor (WGSMR) and oxy-fuel combustion technologies, and pioneers an engineering case to demonstrate its feasibility. By integrating the Rankine cycle, double-effect LiBr absorption chiller, multi-effect distillation unit and CO2 capture plant, waste heat and materials from the prime mover unit are effectively recovered. A comparative analysis of cases with and without WGSMR is conducted to explore its performance improvement potential and mechanisms, while a techno-economic-environmental analysis is performed to comprehensively evaluate the performance of the WGSMR-integrated case. Under the design conditions, the system attains energy and exergy efficiencies of 79.08 % and 30.71 %, with corresponding levelized costs of products and global warming potential of 45.08 $/GJ and −0.21 kg/kWh. At an operating temperature of 700 °C and a current density of 3464 A/m2 of SOFC, the system achieves the minimum levelized cost. Compared with the case without WGSMR, the results demonstrate that the exergy and electrical efficiencies are improved by 2.39 % and 0.95 %, while the levelized cost of products is decreased by 5.29 $/GJ for the case with WGSMR.