Study on process coupling between dry reforming of methane and methanation of carbon dioxide

Both dry reforming of methane (DRM) and methanation of carbon dioxide (MCD) processes offer impressive capabilities for carbon dioxide utilization. However, operating these processes independently involves substantial consumption of natural gas and hydrogen, along with high energy demands, which restrict their broader application. Addressing these challenges is crucial for advancing low-carbon development. This work analyzes the characteristics of two independent processes, namely DRM and MCD. It explores the potential for mass and heat coupling between them, considering the complementary nature of their feedstocks, products, and thermal effects. This investigation leads to the innovative proposal of process coupling schemes for DRM and MCD, marking a pioneering step in this research area. The feasibility of such coupling is assessed through process simulations, examining the characteristics under different situations. The results show that advancements in catalyst technology could enable efficient dual coupling of the DRM and MCD processes in terms of both quality and energy. This coupling process significantly reduces the consumption of natural gas and hydrogen, offering substantial energy savings. In addition, it demonstrates excellent carbon dioxide elimination and utilization capabilities, with the added benefit of flexible adjustability. A key highlight of the DRM‒MCD coupling process is its high mass integration efficiency. Methane produced in the MCD process can serve as a feedstock for DRM, addressing natural gas shortages. Similarly, hydrogen generated by DRM can feed into the MCD, potentially reducing hydrogen usage by at least 26% and mitigating hydrogen resource constraints. Moreover, the coupled process has excellent energy integration. The heat from the exothermic MCD system can be transferred to the endothermic DRM system, leading to significant reductions in energy consumption. When compared to operating the DRM and MCD processes separately, the coupled process could lower total energy consumption by at least 44% and 28%, respectively. This work provides valuable insights for the design and optimization of DRM and MCD process coupling. It underscores the potential engineering applications and feasibility of this approach, contributing to the goal of achieving carbon neutrality by transforming conventional energy and chemical processes.