【摘要】 <正> (一) 催化剂上焦碳生成的机理 炼油工业中,在催化剂上形成的焦碳一般有两种类型。一种是在很高的温度下(>500℃)在金属表面、气相空间或金属催化剂上形成的,它具有连接在一起的树枝形状。如和在金属上分解环已烷和异丙醇,形成的焦碳即成树枝状。更多还原

【Abstract】 The mechanism and kinetics of coke deposition on cracking catalyst have been reviewed. According to Yang Guanghua’s early research work, a kinetic model of three steps coking has been suggested.Regeneration of various zeolite catalysts and silica-alumina catalysts have been investigated.It is found that the regeneration of coked catalysts can be divided into two steps.In the first step the carbon burning reaction is of the first order with respect to the carbon content, but in the second step, when the carbon content is reduced to about 0.1%, the order shifts from first order to a higher order (e.g.3/2 order). It is also found that there is no significant difference between the rate constants of regeneration of various zeolite catalysts. Based on these investigations, kinetic equations have been suggested.The elementary compositions of coke in different extents of regeneration have been investigated. No significant change of C/H ratio in residual coke in the course of burning leads to the suggestion that the hydrogen burning rate is not faster than carbon burning rate.更多还原