Disk-shaped packed bed micro-reactor for butane-to-syngas processing

A novel disk-shaped packed bed micro-reactor containing Rh/ceria/zirconia nanoparticles is investigated with respect to catalytic butane-to-syngas processing at moderate temperatures of 550 °C. The main goal of this study is the development of an efficient butane processor which can be integrated into a micro solid oxide fuel cell system due to its small size, easily packaged geometry in layered microdevices, high compactness, low pressure drop, and low reaction temperature. It is shown that Rh/ceria/zirconia has an excellent long-term stability and achieves very high C4H10 conversion and syngas selectivity, considering the relatively low operating temperature. The yields of H2 and CO can be increased up to 71% and 57%, respectively, by optimizing operational parameters such as the C/O ratio and the total inlet flow rate. The introduced disk-shaped packed bed reactor shows significant advantages in catalytic behavior, at a 6.5 times lower pressure drop compared to an equivalent tubular packed bed reactor. This increased catalytic performance is pursued extensively by investigating possible reaction pathways in three regions of the radial-flow reactor, leading to the significant discovery of a threefold pathway of syngas production on a single catalyst. To this end, it is shown that the excellent selectivities to H2 and CO for high flow rates are due to the combination of partial oxidation, steam reforming, and dry reforming of C4H10, indicating one direct and two indirect reaction paths.