论文部分内容阅读
采用溶剂蒸发自组装法调控载体形貌及孔道结构,成功制备了有序介孔氧化铝载体。以铬氧物种为活性组分,碱金属钾为助剂,采用浸渍法制备负载型催化剂,用于异丁烷催化脱氢反应,研究了反应温度、原料流速、催化剂粒径等因素对催化性能的影响。采用X射线粉末衍射、透射电子显微镜、N_2物理吸附、氢气程序升温还原及热重等表征方法探讨了载体形貌、孔道结构与催化性能的构效关系,结果表明,低温下有利于控制异丙醇铝的水解和缩合及介孔γ-Al_2O_3的研制。与常规的γ-Al_2O_3相比,所制备的介孔γ-Al_2O_3的有更大的比表面积和良好的有序性,在600℃、101.325kPa、GHSV=1 000 h~(-1)的条件下,10%(w/w)Cr_2O_3/γ-Al_2O_3催化剂性能最佳,异丁烷的转化率达63.1%,异丁烯的选择性达到85.5%。与传统的催化剂相比,介孔Cr_2O_3/γ-Al_2O_3催化剂具有大的比表面积,高度分散的活性组分,优良的催化性能和良好的抗积碳能力。
Solvent evaporation self-assembly method to control the morphology and pore structure of the carrier, successfully prepared ordered mesoporous alumina carrier. Using chromium oxygen species as active component and alkali metal potassium as auxiliary, the supported catalyst was prepared by impregnation method for the catalytic dehydrogenation of isobutane. The effects of reaction temperature, flow rate of feedstock and catalyst particle size on the catalytic performance Impact. X-ray powder diffraction, transmission electron microscopy, physical adsorption of N 2, temperature-programmed reduction of hydrogen and thermogravimetry were used to investigate the structure-activity relationship of the morphology, pore structure and catalytic performance of the support. The results show that the low- Hydrolysis and condensation of aluminum alcoholate and preparation of mesoporous γ-Al_2O_3. Compared with the conventional γ-Al 2 O 3, the prepared mesoporous γ-Al 2 O 3 has larger specific surface area and good orderliness. Under the condition of 600 ℃, 101.325kPa and GHSV = 1000 h -1 Under the optimal conditions, 10% (w / w) Cr 2 O 3 / γ-Al 2 O 3 catalyst has the best performance. The conversion of isobutane is 63.1% and the selectivity of isobutene is 85.5%. Compared with the traditional catalyst, the mesoporous Cr 2 O 3 / γ-Al 2 O 3 catalyst has large specific surface area, highly dispersed active components, excellent catalytic performance and good anti-carbon ability.