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Preparation of High Temperature Shift Catalyst

Haghighi, Farzad | 2016

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 48710 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Baghalhs, Morteza; Kazemeyni, Mohammad
  7. Abstract:
  8. Water-gas shift reaction (CO(g) + H2O(g) ↔ CO2(g) + H2(g)) is performed as the key step in the hydrogen and ammonia industrial plant. In this work, Fe/Cr/Cu high temperature water gas shift catalysts were synthesized by coprecipitation method, using sulfate precursors, in order to improve the catalytic performance and particular emphasis is placed on the catalytic activity affected by aging time, precipitating agent and ways of increasing the mechanical strength. Finally the prepared and industrial catalysts were compared when they were situated in the operating conditions (at 360oC and 2 bar) and were characterized by BET, XRD, TPR, TEM and crushing strength analysis. Catalysts being made from NaOH precipitator were prepared in 8 different aging times. After 120 hours locating in the operating conditions, the prepared catalysts with 90 and 180 minutes aging time were shown 48.22 and 50.44% conversion respectively, so 90 and 180 minute were selected as the best times of aging. Then the effect of the Na2CO3 and NaOH-Na2CO3 (50-50% mixture) as the precipitating agents on the catalytic activity were investigated at 90 and 180 minutes aging times. The HTS-Na2CO3-90, HTS-Na2CO3-180, HTS-NaOH-Na2CO3-90 and HTS-NaOH-Na2CO3-180 catalysts were shown 54.44, 50, 56.78 and 57.22% conversion respectively that were more active in comparison with HTS-C12 and HTS-CTK industrial catalysts with 53 and 41.22% conversion respectively. The catalysts being prepared from Na2CO3 precipitator were shown higher decrease of activity due to thermal sintering under reaction condition. The effect of adding Mg(OH)2, MgCO3 and cement promoters were investigated on the mechanical strength and the results showed that these promoters can increase the mechanical strength 147, 76 and 87% respectively. However, it decreased the conversion 60, 49 and 63% respectively
  9. Keywords:
  10. Water Gas Shift (WGA)Reaction ; Aging ; Mechanical Strength ; Iron Oxid - Zinc Oxid Catalysis ; Precipitutor Agent

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