Investigation of a hydrogen generator with the heat management module utilizing liquid-gas organic phase change material

Abstract

Hydrogen carriers have been actively explored as a viable option for safe and economical hydrogen storage and transportation. However, the highly endothermic nature of dehydrogenation reactions results in a considerable temperature nonuniformity due to severe heat transfer limitations. To address this issue, a bench-scale catalytic reactor for hydrogen production is developed from methanol steam reforming (MSR) using a liquid-gas organic phase change material (PCM) working at a medium temperature range (200 degrees C-300 degrees C) and near-ambient pressure conditions. First, a comparative study was conducted to quantify the temperature homogeneities with or without adopting PCM; the former showed a higher temperature uniformity, leading to an improved hydrogen production rate and system efficiency. Additionally, a rapid start-up and uniform temperature profile of the catalytic bed at a steady state by the thermal management of the PCM were manifested. The liquid-gas organic PCM was stable during MSR at 250 degrees C, despite minor oxidation. For the feasibility study on a bench scale, 0.6 kW(e)-level hydrogen generation (equivalent to 5.83 kW(e)/L-reactor) using the PCM-based reactor was demonstrated. This work can provide insights into the scale-up and thermal management of various catalytic dehydrogenation reactors encompassing considerable heat absorption or release.