Simulation of a moving bed chemical looping system for electricity production from coal via chemical looping water splitting

Abstract

AbstractCoal is a crucial energy source for modern industry and society. Because coal is one of the most CO2‐intensive carbonaceous fuels, the combustion of coal with CO2 capture is of great environmental relevance. However, the conventional coal‐based power generation processes, including the pulverized coal (PC) boiler process and the integrated gasification combined cycle (IGCC) process, suffer a significant efficiency loss when integrated with conventional CO2 capture methods. Chemical looping technology is a promising alternative pathway for coal‐based power generation with intrinsic CO2 separation and capture. Process simulation of chemical looping processes can provide an overview on the viability of the processes, thereby quantifying their advantages over conventional processes. This study presents the process simulation of a chemical looping water splitting combined cycle (CLWS‐CC) system for electricity generation. The CLWS‐CC process directly uses coal as the feedstock to produce H2, which is subsequently combusted in a combined cycle to generate electricity. The oxygen carriers used in the chemical looping process are optimized in their composition. Autothermal operation is established within the chemical looping system. Four CLWS‐CC cases that operate at different pressures are considered. In two of the four cases, an unequal pressure operating strategy is adopted to minimize the compression power consumption in order to enhance the overall process energy efficiency. The process simulation shows that the CLWS‐CC process is able to achieve an 18% increase in net plant efficiency over the conventional IGCC process.