Enhanced Investigation of CO Methanation over Ni/Al2O3 Catalysts for Synthetic Natural Gas Production

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• 作者：Dacheng Hu ; Jiajian Gao ; Yuan Ping ; Lihua Jia ; Poernomo Gunawan ; Ziyi Zhong ; Guangwen Xu ; Fangna Gu ; Fabing Su
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2012
• 出版时间：April 4, 2012
• 年：2012
• 卷：51
• 期：13
• 页码：4875-4886
• 全文大小：744K
• 年卷期：v.51,no.13(April 4, 2012)
• ISSN：1520-5045

文摘

CO methanation reaction over the Ni/Al₂O₃ catalysts for synthetic natural gas production was systematically investigated by tuning a number of parameters, including using different commercial Al₂O₃ supports and varying NiO and MgO loading, calcination temperature, space velocity, H₂/CO ratio, reaction pressure, and time, respectively. The catalytic performance was greatly influenced by the above-mentioned parameters. Briefly, a large surface area of the Al₂O₃ support, a moderate interaction between Ni and the support Al₂O₃, a proper Ni content (20 wt %), and a relatively low calcination temperature (400 掳C) promoted the formation of small NiO particles and reducible 尾-type NiO species, which led to high catalytic activities and strong resistance to the carbon deposition, while addition of a small amount of MgO (2 wt %) could improve the catalyst stability by reducing the carbon deposition; other optimized conditions that enhanced the catalytic performance included high reaction pressure (3.0 MPa), high H₂/CO ratio (鈮?:1), low space velocity, and addition of quartz sand as the diluting agent in catalyst bed. The best catalyst combination was 20鈥?0 wt % of NiO supported on a commercial Al₂O₃ (S₄) with addition of 2鈥? wt % of MgO, calcined at 400鈥?00 掳C and run at a reaction pressure of 3.0 MPa. On this catalyst, 100% of CO conversion could be achieved within a wide range of reaction temperature (300鈥?50 掳C), and the CH₄ selectivity increased with increasing temperature and reached 96.5% at a relatively low temperature of 350 掳C. These results will be very helpful to develop highly efficient Ni-based catalysts for the methanation reaction, to optimize the reaction process, and to better understand the above reaction.