Development of a powerful CO₂ methanation process using a structured Ni/CeO₂ catalyst

The purpose of this study is to develop a powerful CO₂ methanation process using a variety of structured Ni/CeO₂ catalysts. Various configurations of metallic honeycomb-type catalysts, which are plain, stacked, segment, and multi-stacked were constructed and tested under various reaction conditions; i.e. inlet temperature, feed flow rate and CO₂ partial pressure. Effects of the developed configurations including stack and gap distance were examined. The random-flow channels of stacked type and the gap distance of segment type could improve the catalytic activity, resulting in high CO₂ conversion. Under industrial-like high feed rate condition and pure feed gas component, a moderate hot spot over the multi-stacked catalyst was observed and reported for the first time. The moderate hot spot reboosted the conversion to a high level even at high feed flow rate condition of 3000 mL/min (contact time of 235 ms). As a result, high CO₂ conversion > 90%, high CH₄ selectivity > 99.5%, and high stability with dropped conversion < 0.6%, could be maintained over 76 h test at setting temperature of 300 °C, flow rate of 3000 mL/min and feed ratio of p_CO2/ p_H2=0.12/0.88. The stability of the Ni/CeO₂ catalyst under the moderate hot spot condition was revealed by BET, SEM and XRD analyses.