Abstract The development of catalysts for dehydrogenation of light paraffin hydrocarbons in a fixed bed reactor is of great importance for the world petrochemical industry. The preparation of granules (∼3 mm in diameter) of CrOx/Al2O3 catalysts is hindered by such problems as homogeneous distribution of active component and modifiers, high strength of granules, etc. In this paper, the alumina support dissolution in the impregnating solution containing chromic acid and the opportunity to apply vacuum impregnation to minimize this effect in the preparation of CrOx/Al2O3 catalysts are discussed. A series of catalysts is synthesized at different impregnation pressures (1, 0.85, and 0.7 atm), characterized by a complex of physical-chemical methods (low-temperature N2 adsorption, SEM, XRD, TPR-H2), and tested in isobutane dehydrogenation. The use of vacuum impregnation is shown to lead to the reduction of the specific surface area of the catalysts from to 91 to 56 m2/g and the growth of content of CrOx phases that decreases the catalytic activity in dehydrogenation. The isobutylene yield at 610 oC decreases from 68 % to 54 % for the catalyst prepared at P=0.7 atm as compared with the one prepared at atmospheric pressure. The high activity and stability are connected with the hierarchical structure of the alumina support and homogeneous chromia distribution on its surface.

中文翻译：

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浸渍条件对固定床反应器异丁烷脱氢CROX/AL2O3催化剂活性的影响

摘要 开发固定床反应器轻质链烷烃脱氢催化剂对世界石油​​化工行业具有重要意义。CrOx/Al2O3 催化剂颗粒（直径约 3 mm）的制备受到活性组分和改性剂分布均匀、颗粒强度高等问题的阻碍。讨论了铬酸以及在制备 CrOx/Al2O3 催化剂时应用真空浸渍以将这种影响降至最低的机会。在不同的浸渍压力（1、0.85和0.7个大气压）下合成了一系列催化剂，通过复杂的物理化学方法（低温N2吸附、SEM、XRD、TPR-H2）进行表征，并在异丁烷脱氢中进行测试. 显示使用真空浸渍导致催化剂的比表面积从 91 到 56 m2/g 减少，并且 CrOx 相含量的增加会降低脱氢催化活性。与在大气压下制备的催化剂相比，在 P=0.7 atm 下制备的催化剂在 610 oC 下的异丁烯产率从 68% 降至 54%。高活性和稳定性与氧化铝​​载体的分级结构及其表面均匀的氧化铬分布有关。7 个大气压与在大气压下制备的相比。高活性和稳定性与氧化铝​​载体的分级结构及其表面均匀的氧化铬分布有关。7 个大气压与在大气压下制备的相比。高活性和稳定性与氧化铝​​载体的分级结构及其表面均匀的氧化铬分布有关。