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

2012    American Chemical Society


Abstract

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.

Publication Authors

Name

Affiliation

Bonan Liu

Inorganic Chemistry Laboratory, Oxford University

 Qiuyun Zong

Qindao Lianxin Chemical, Qingdao, Shandong Province, P R China

Edwards, Peter P

Inorganic Chemistry Laboratory, Oxford University

 Fei Zou

Inorganic Chemistry Laboratory, Oxford University

 Xian Du

Inorganic Chemistry Laboratory, Oxford University

 Zheng Jiang

Inorganic Chemistry Laboratory, Oxford University

 Tiancun Xiao

Inorganic Chemistry Laboratory, Oxford University

AlMegren, Hamid

Petrochemical Research Institute, King Abdulaziz City for Science and Technology

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