Experimental and numerical investigations on structured catalysts for methane steam reforming intensification

Abstract

Hydrogen production for green energy purposes arouses attention of industrial and scientific research. Despite a growing interest towards distributed hydrogen production, difficulties due to the heat and mass transfer limitations in the steam reforming processes reduces the possibility of small scale plants, and dramatically increases fixed and operative costs. Highly thermal conductive honeycomb structures were proposed as catalyst supports for hydrogen-rich stream production by methane steam reforming to enhance the heat and material transfer properties of catalysts, in order to increase the process sustainability. This work focuses on the experimental testing and preliminary numerical modeling of the methane steam reforming reaction performed on a Nickel-loaded silicon carbide monolith packaged into an externally heated tube. In particular, the two flow configurations of Flow Through and Wall Flow were investigated and compared, the impact of a washcoat deposition was evaluated. The wall-flow catalytic configuration is an innovative solution in the reforming processes, no examples were reported in the literature. A preliminary steady-state heterogeneous 3D model was developed including momentum, mass and energy balances. The experimental tests as well as the numerical simulations indicate that the Wall Flow configuration may overcome the fixed-bed reactor problems, yielding a more uniform temperature distribution and more effective mass transport. The highly conductive supports in wall-flow configuration appeared so able to minimize typical reforming processes limitations, improving the overall catalytic system kinetics and so resulting in an appreciable process intensification.