Study Of Catalysts For Methanation From Syngas To Synthetic Natural Gas

As a kind of energy, natural gas is efficient and superior. The production of synthetic natural gas?SNG? has attracted lots of attention, it can solve the problem of energy shortage and it's environmentally friendly. China owns abundant coal resources, the technical developing of coal-based natural gas production is critical for the effective usage of coal. Methanation is the key process of SNG production, this paper focused on the study of Co-based catalysts for methanation.Nanosized Co₃O₄ particles were prepared using a facile precipitation method. The physicochemical properties of catalysts were characterized by a series of technologies. It was found that Co₃O₄ nano-particles were highly active for CO methanation. By diluting with Al₂O₃, the stability of catalyst was improved. The optimal operation condition of Co₃O₄ nano-particles was obtained in this study.The different chemical valence states of Co species were obtained by adopting various reduction processes before methanation. The catalytic activities for CO methanation were investigated over catalysts with different reduction treatments. Combining the results of characterization with evaluation, it can be concluded that CoO is the active phase for CO methanation. The reduction treatment can improve the stability of catalyst.Supported Co-based catalysts were prepared to further improve the stability of Co₃O₄ nano-particles. The effect of Co loading, supports and the preparation methods on Co/Al₂O₃ catalysts were studied in this work.Catalytic performance of Co₃O₄ for sulfur-resistant methanation was also investigated in the study. The activities of 25%MoO₃/Al₂O₃ and 5%CoO-25%MoO₃/Al₂O₃ catalysts in sulfur-resistant methanation were examined as H₂S concentration varied from 0.00 to 1.20 vol.%. It was found that Co has a promotion effect to 25%MoO₃/Al₂O₃ catalyst only when H₂S concentration is higher than 0.40 vol.%. When H₂S concentration is lower than 0.40 vol.%, addition of Co exhibits inhibition effect on 25%MoO₃/Al₂O₃ catalyst. The research gave the appropriate range of H₂S concentration to add Co promoter on MoO₃/Al₂O₃ catalyst, thus could help the selection of catalysts in industry.