Perspective Chapter: Numerical Investigations on the Regulation of Temperature Distribution in Packed Bed for Exothermic Reactors

The integration of hydrogen production with CO2 methanation facilitates the use of existing natural gas infrastructure while lowering CO2 emissions, thereby removing the necessity for new facilities dedicated to hydrogen transport, storage, and application. However, the CO2 methanation process is inherently highly exothermic. Elevated reactor temperatures can induce catalyst thermal degradation, sintering, and carbon deposition, which ultimately result in catalyst deactivation and reduced CH4 production. In this study, numerical simulations were conducted to investigate hot-spot formation and temperature regulation in fixed-bed reactors. The results demonstrated that enhancing catalyst pellet heat transfer significantly suppresses hot spots while maintaining carbon conversion. Furthermore, an optimal packed-bed dilution strategy employing inert particles was identified. This approach can control the hotspot temperature within the operating range of the catalyst, preventing deactivation caused by high temperatures. Additionally, a “CHESS” monolith design was proposed for packed-bed reactors. This design not only sustains high carbon conversion but also enhances heat transfer. The performance of radial flow reactors was explored as well. It was found that the centripetal Z-type radial flow reactor exhibited the best performance. These findings provide valuable insights into temperature management in fixed-bed reactors for CO2 methanation.