A solar assisted polygeneration system integrating methane reforming and chemical looping combustion with zero carbon emission

Abstract

The capture and utilization of CO₂ is aimed at conserving fossil fuels and reducing greenhouse gas emissions by providing an alternative carbon feedstock and closing the carbon cycle. This paper combines chemical-looping combustion (CLC) and methane reforming with CO₂ to accomplish CO₂ capture and utilization and proposes a novel polygeneration system to produce syngas, electricity, chilled water for cooling, and hot water. In this cycle, CLC, assisted by solar thermal energy, is employed to drive turbines to produce electricity and to separate CO₂ after the recovery of waste heat from high temperature gas. The reaction in the reformer of separated CO₂ and methane is driven by solar thermal energy to produce syngas. A part of the produced syngas fuel is sent to CLC such that CLC and methane reforming are coupled in this polygeneration system. The thermodynamic performance of the polygeneration system, including the energy and exergy efficiencies, are analyzed and compared on the basis of design conditions. In addition, the energy utilization diagram (EUD) analysis reveals the mechanism for the improvement and enhancement of the system performance in the novel system. The results indicate that the energy and exergy efficiencies approach 71% and 56%, respectively. Meanwhile, the instantaneous solar share is approximately 46%, and the net solar-to-exergy efficiency approaches 25%. The maximum exergy destruction of the system occurred in the chemical reaction sub-system.