Preparation The Ctalyst Of Chromium And Isobutane Dehydrogeation Process Research

At present, the main source of isobutylene are: oil refineries FCC process by-product, joint production of heat and steam cracking of olefins isobutane dehydrogenation. By preparing isobutylene isobutane dehydrogenation is the petrochemical field and one of the topics of economic and social benefits, can not only improve the C4 hydrocarbon additional use value, and can meet the increasing demand of C4 olefin. There are two kinds of isobutane dehydrogenation catalyst: Pt catalyst and Cr catalyst. Among them, the Pt catalyst is expensive, and it requires high content of impurities in raw material, prone to active component in the process of reaction sintering; Relatively, Cr series catalyst for impurity content of material requirement is not high, the price is relatively cheap, its disadvantage is that the catalyst stability, easy carbon deposit catalyst deactivation, need frequent regeneration. Therefore, urgent need to develop a high activity, selectivity and good stability, low price of new Cr system isobutane dehydrogenation catalysts.Based on gamma Al2O3 as the carrier, respectively made Cr/Al2O3, CrA/Al2O3, CrB/Al2O3, CrC/Al2O3 catalyst used for isobutane dehydrogenation isobutylene reaction, and the catalysts were characterized by various means. To determine the best Cr load in the Cr/Al2O3 catalyst. Although Cr/Al2O3 catalyst has higher initial reactivity, but poor stability and isobutene selective reaction. A moderate amount of additives are added can obviously improve the Cr/Al2O3 catalyst of isobutane dehydrogenation reaction performance, XRD and the measurement of specific surface area and FT- IR, H2- TPR technology such as the physical structure, surface properties of the catalysts, the interaction between metal and carrier were characterized. A moderate amount of alkali addition not only reduces the Bronsted acid and Lewis acid catalyst, and improves the dispersion of catalyst on the surface of Cr, compared with Cr/Al2O3 catalyst, CrM/Al2O3(M = A, B, C) catalyst of carbon ability, reaction good stability, and to determine the optimum content of C is 2 wt %.Studied the carbon deposition of Cr/Al2O3 catalyst deactivation, deduce the Cr/Al2O3 catalyst amount of carbon deposition at the beginning of the reaction with the reaction time in the form of power function relation between the type and carbon deposition rate. Examines the different reaction temperature, the quality of isobutane airspeed, feed gas composition and other conditions affect the performance of catalyst isobutane dehydrogenation reaction, determine the optimum reaction conditions of Cr/Al2O3 catalyst.The step of the OS-Cr/Al2O3 series catalyst used for isobutane dehydrogenation reaction, and through a variety of characterization methods to investigate the structures and properties of the catalyst. Cr load, Cr(OH)3 rest time, the type of carrier, the C addition amount of OS-CrC/Al2O3 catalyst isobutane dehydrogenation performance impact. And examines the different reaction conditions on the OS-1CrC/Al2O3 catalyst performance impact of isobutane dehydrogenation reaction. Crca results show that the OS-1CrC/Al2O3 series isobutane dehydrogenation catalyst reaction performance is stable, comprehensive adjusting reaction conditions can obviously increase the reactivity and stability of the catalyst, the catalyst has good dehydrogenation- regeneration performance, after simple regeneration can restore a certain activity. Using this method to develop OS-1CrC/Al2O3 catalyst has good application prospect.