(683e) Methane Reforming and Sequential Fischer-Tropsch: A Modeling Study of a Single-Reactor Process

Among the most critical areas of research and development is that of efficient energy conversion. Despite this, the transportation industry remains poised to continue reliance on fossil fuels in the coming years. This necessitates continued efforts in the study of clean, economical, hydrocarbon fuel synthesis.

Of the proposed solutions, Fischer-Tropsch synthesis (FTS) is particularly attractive. Despite being a well-known approach to synthetic fuel, it has been hindered by economies of scale leaving the process with no current means of environmentally and economically friendly, large-scale application. The limiting factor arises in production of syngas which traditionally utilizes energy intensive steam reforming.

One approach to resolving this issue is in combining the FTS and reforming steps into a single, intensified reactor system utilizing two catalysts and operating under moderate pressure and temperature conditions. To better understand this system and guide experimental efforts, a multiscale model incorporating kinetics, and mass/heat transfer has been developed. The model utilizes kinetics adapted from literature including the Xu and Froment kinetics of steam reforming and an ASF approach to modeling FTS for an iron catalyst. The kinetics were fit using experimental data from our group and the mass and heat transfer verified using literature data. Using this model, we screened feed compositions, operating conditions and catalyst bed configurations to observe their impact on the hydrocarbon product.

Due to thermodynamic limitations, the reforming and FTS sections must be maintained at separate temperatures. Leveraging the endothermic and exothermic reactions and an analysis of proposed heat exchanger designs, the model provided insights on areas on which experimental efforts would be best focused. Properly applied, multiscale models such as this provide essential qualitative information on experimentally complex systems. This accelerates understanding and advancement toward essential goals such as economical, cleaner energy.