Efficient methane reforming at proper reaction environment for the highly active and stable fibrous perovskite catalyst

Abstract

The purpose of this work is to investigate proper hydrogen production methods from methane through the parametric study for the highly active and stable nanofibrous perovskite catalyst. A ruthenium doped lanthanide chromate (LaCr0.8Ru0.2O3) micro-fibrous perovskite catalyst is prepared and fixed to focus on the effect of reaction environments such as steam, partial oxidation and autothermal conditions. Temperatures, H2O/C and O2/C ratios were occasionally changed for the investigation of the effects and the optimization conditions. At the same perovskite catalyst system, the reaction at the autothermal atmosphere is the most effective conditions in terms of both CH4 conversion and H2 production, which was comparable to the theoretical calculations. It is found that conversion increases with oxygen at even low temperature while the H2 productivity increases with much stable behavior at steam condition. These are more obvious at the elevated temperature with each optimized H2O and O2 amounts for high activity by low activation energy. Time-on-stream runs conducted on these three reactions with each optimized conditions of 50h at 800°C, H2O/C=3 and O2/C=0.5. The perovskite micro-fiber catalyst at autothermal condition shows excellent CH4 conversion of over 95%, H2 production of around 70%, and even H2/CO of over 4. On the other hand, the reactivity at the steam condition is lower and even slow. The durability at the partial oxidation condition starts to decrease after 10h due to the instability of the perovskite at the extremely oxidative concentration which causes a relatively high coke formation. Therefore, it is worthwhile in suggesting proper autothermal reaction conditions for the highly active and stable perovskite catalyst like LaCr0.8Ru0.2O3 micro-fibers.