Integration of solid oxide fuel cell (SOFC) and chemical looping combustion (CLC) for ultra-high efficiency power generation and CO2 production

摘要

This work presents a thermodynamic analysis of the integration of solid oxide fuel cells (SOFCs) with chemical looping combustion (CLC) in natural gas power plants. The fundamental idea of the proposed process integration is to use a dual fluidized-bed CLC process to complete the oxidation of the H-2-CO-rich anode exhausts from the SOFC in the CLC fuel reactor while preheating the air stream to the cathode inlet temperature in the CLC air reactor. Thus, fuel oxidation can be completed in N-2-free environment without the high energy and economic costs associated to O-2 production, avoiding at the same time the high temperature and high cost heat exchanger needed in conventional SOFC plants for air preheating. In the proposed configurations, the CLC plant is operated at mild conditions (atmospheric pressure and temperature in the range of 700-800 degrees C), already demonstrated in several pilot plants. Two different scenarios have been investigated: in the first one, the SOFC is designed for large-scale power generation (100 MWLHV of heat input), featuring a heat recovery steam cycle and CO2 capture for subsequent storage. In the second scenario, the system is designed for a small-scale plant, producing 145 kg/h of pure CO2 for industrial utilization, as a possible early market application.