Process integration of coal fueled chemical looping hydrogen generation with SOFC for power production and CO2 capture

Abstract

Chemical looping hydrogen generation (CLHG) is integrated with solid oxide fuel cell (SOFC) and combined cycle for high-efficiency power production with CO2 sequestration. To avoid energy penalty imposed by cryogenic air separation unit for oxygen production, the CLHG is directly fed by coal. The coal gasification and iron oxide reaction occur in the same reactor and no gaseous oxygen is used in gasification. The CLHG operates at an auto-thermal condition by solid circulation. The proposed system could achieve a net power efficiency of 41.59% at a baseline case. Sensitivity analysis is conducted as well on the basis of heat balance. Varying the temperatures of CLHG reactors and iron oxide circulation rate influences the system's efficiency. The increase of the fuel cell's temperature and fuel utilization factor favors the system's net power efficiency. In addition to high net power efficiency, the CO2 capture rate of the proposed system is up to ∼100%, resulting in a virtual carbon-free power plant.