Thermodynamic analysis of a novel compressed carbon dioxide energy storage coupled dry methane reforming system with integrated carbon capture

Chemical absorption CO₂ capture, compressed carbon dioxide energy storage (CCES) and dry reforming of methane (DRM) can be used for continuous carbon capture, storage and utilization. However, CO₂ capture is often accompanied by significant energy consumption. Considering the waste high-grade thermal energy at the exit of solar methane reforming, the article proposes a coupled system in which the thermal energy at the exit of the DRM system is used in CCES to improve the system's work capacity, and the remaining heat and the compression heat of the CCES are used for CO₂ capture. The study established mathematical models of the three subsystems, performed thermodynamic analyses, and completed experiments on dry reforming of methane. The results show that the coupled system can increase the electro-electric conversion efficiency by 150.49 % reaching 220.33 % and the energy efficiency by 7.25 % reaching 77.09 %. The coupled system can save up to 43.33 % of CO₂ capture heat. The DRM subsystem can utilize the higher temperature CO₂ in the tail end of the CCES system, and its methane conversion efficiency and solar-fuel efficiency can be increased by 3.54 % and 3.20 % respectively to reach 58.22 % and 61.02 %. And the economic analysis found that the coupled system has better economics.