【摘要】 利用纯烃重整反应,TPT(程序升温滴定)及氢溢出等实验方法,研究铂锡、铂铼及铂铱双金属重整催化剂中第二金属组元作用.在500℃、0.980MPa条件下,正庚烷、甲基环戊烷以及环戊二烯-正庚烷混合原料的连续反应表明,锡组元必须与铂共载,在邻近铂的情况下才能发挥其作用,即能调节其金属功能,在改善催化剂选择性的同时提高稳定性,而分载铂锡催化剂则与单铂催化剂性能一样.铼组元无论是共载或分载均能起到类似作用,既有使积炭前身物开环裂解作用,又能使其选择性加氢而被消除掉的作用。在高温下,铱组元与铼组元同样地能产生氢溢出,分载铱与共载铱性能类似,都具有较强的开环裂解作用,它能提高催化剂的稳定性;主要是通过破坏积炭前身物减少积炭生成.更多还原

【Abstract】 The role of Re, Sn and Ir in supported platinum catalysts was studied in the reforming of normal heptane, methylcyclohexane, methylcyclopentane and cyclopentadiene （CPD） in a continuous flow type microreactor under pressure.TPT and hydrogen spillover tests were also carried out for this purpose. In Pt-Sn catalysts, Sn was found to stabilize the catalyst and suppress hydrocracking, hydrogenolysis and ring opening reactions only in the cosupported state. Physical mixtures of Pt/Al₂O₃ and Sn/Al₂O₃ was found to be similar in catalytic behaviour to mono-metallic Pt catalysts, Sn in the vicinity of Pt can modify the hydrogenation-dehydrogenatlon function of the bifunctional catalyst so that the formation of CPD type coke precursors is suppressed. It has been known that Re increases the stability of Pt catalysts no matter whether it exists in cosupported or separately supported form. Work in our laboratories including model compound studies and TPT and hydrogen spillover tests suggests the possibility at Re is capable of converting coke precursors into harmless products by two mechanisms, i. e. cracking and ring opening as well as selective hydrogenation of CPDs. Ir has higher activity than either Re or Sn for hydrogenolysis. In this work, it was found that separately supported Ir can also intercept and destroy the coke precursors, thus increasing the catalyst stability.更多还原