Investigation of packed conductive foams as a novel reactor configuration for methane steam reforming

Abstract

• Packed foams successfully applied to SMR process. • Systematic increase of productivity noted at fixed oven temperature. • Foam conductivity enhances heat transfer properties. • Development of a heat transfer model for packed foams. In this work, a novel fixed bed reactor configuration is proposed and tested for the steam reforming of methane; the proposed solution consists of filling the voids of highly conductive metallic open-cell foams with small catalytic pellets. This reactor layout aims at enhancing the radial heat transfer of the tubular reactor by exploiting the thermal conductivity of the solid interconnected matrix, while keeping a target catalyst inventory and avoiding issues related to washcoating of metallic structures. Tests were performed using a Rh/Al 2 O 3 catalyst in the form of alumina egg-shell particles, with diameter of 600 μm. FeCrAlY open cell foams of 12 PPI and copper open cell foams of 10 and 40 PPI were compared to a conventional packed bed system; experiments were performed at GHSV of 5000 and 10000 h −1 at oven temperatures in the 600–800 °C range. Experiments demonstrated a benefit in terms of the thermal management of the reactor and an increase of productivity at the same furnace temperature in kinetically-limited conditions. A heat transfer model of the packed foams was developed based on the approach of electric equivalent circuit; the model incorporates independently estimated lumped or effective parameters and provides an engineering rationale of the observed reduction of temperature gradients across the catalytic bed.