碳二加氢精制催化剂研究进展

催化选择加氢工艺技术是提纯裂解烯烃最普遍的方法,而碳二加氢精制催化剂是乙烯分离工艺流程的关键技术之一。介绍了国内外碳二选择性加氢精制催化剂的发展现状,包括催化剂的制备工艺、催化剂的载体、活性组分及助催化剂的进展情况。对碳二馏分选择性加氢反应机理进行了探讨,深入分析了空速、反应温度、一氧化碳浓度及氢炔比等因素对催化剂使用性能的影响。提出了碳二加氢精制催化剂的发展方向,一是加强对蛋壳型催化剂的研究,将活性组分钯分布在载体表面壳层,使钯层更薄,提高钯的利用率,使之表现出更好的碳二加氢反应活性和乙烯选择性;二是通过添加其他组分对钯基催化剂进行改性,发展多组分钯基催化剂,以提高乙烯选择性、减少绿油生成量和延长催化剂运行周期。因此,开发出高活性、高乙烯选择性、高空速、低绿油生成量、再生性能更好的非贵金属催化剂具有现实意义。

辊道窑焙烧碳选择加氢催化剂载体应用研究

将辊道窑作为高温热源,通过设定合适的焙烧曲线和各级棍棒传动频率,连续焙烧碳二/碳三选择加氢催化剂载体;分析数据表明,辊道窑焙烧结果良好,并提出了温度与比表面的线性关系;总结了利用辊道窑焙烧载体的不足,并提出了一定的参考意见;利用辊道窑焙烧载体,其优点突出,适宜于推广应用于催化剂载体焙烧。

Shape Selective Hydrogenation of Alkenes with Supported Pd@MOF-5 Catalyst in Supercritical Carbon Dioxide

The metal-organic framework MO-5 has been synthesized by solvothermal method. Obtained material consists of nano-sized particle of ca. 100 nm size. The material has been physico-chemical characterized regarding structural and textural properties by XRD, FTIR, nitrogen adsorption/desorption, thermal analysis and ESA experiments. Palladium supported MOF-5 catalyst has been prepared by adsorption inclusion method. The catalyst was activated by treatment with supercritical carbon dioxide （scCO2） followed by mild reduction with hydrogen solved in scCO2. The obtained catalyst is shown to be stable and active and shape selective in hydrogenation reactions of alkenes using supercritical carbon dioxide as reaction medium. The catalytic active Pd species are located inside the pores. Positive surface charging seems to prevent deposition of active species at the crystal surface of the MOF. The catalyst is long time stable and re-useably. These findings show the potential of porous MOFs for applications under supercritical conditons and resisted repeated pressuring to 120 bar at elevated temperature.