Effect of Titania Addition on the Performance of CoMo/Al2O3 Sour Water Gas Shift Catalysts under Lean Steam to Gas Ratio Conditions

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• 作者：Bonan Liu ; Qiuyun Zong ; Peter P. Edwards ; Fei Zou ; Xian Du ; Zheng Jiang ; Tiancun Xiao ; Hamid AlMegren
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2012
• 出版时间：September 12, 2012
• 年：2012
• 卷：51
• 期：36
• 页码：11674-11680
• 全文大小：480K
• 年卷期：v.51,no.36(September 12, 2012)
• ISSN：1520-5045

文摘

CoMo/Al₂O₃ sour water gas shift catalysts with and without TiO₂ modification have been tested in parallel industrial reactors under lean steam/gas conditions for two years, and part of catalyst samples was taken out each year during the maintenance period. The catalyst samples have been characterized using temperature programmed sulfurization (TPS), X-ray diffraction (XRD), and laser Raman and BET surface area measurements. The results have shown that adding TiO₂ to the catalyst makes the active components, e.g., Mo and Co, easier to be sulfurized with higher sulfur capacity in the catalyst itself. This may be the main reason why the TiO₂ modified CoMo catalyst to be active even at low H₂S gas stream. The results from industrial operation showed that adding TiO₂ to the shift catalyst increases the catalyst activity and stability, presents the higher shift activity in a broader range of H₂S content, depresses the aggregating of the molybdenum oxide, and reduces carbon deposition. In addition, the TiO₂ additive in the catalyst also helps to maintain the physical properties of the shift catalysts. In the freshly prepared catalyst, the active components e.g., MoO₃ is mainly present in the internal surface or sublayer of the catalyst, but it gradually migrates to the catalyst surface with the time on stream. In summary, the CoMo/Al₂O₃ based sour water gas shift catalyst showed stable shift performance under the lean steam/gas conditions, adding TiO₂ to the catalyst significant improves the catalyst activity and resulting into stable operation in the industrial reactor operation in a wide range of H₂S concentrations.