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通常催化剂的积炭失活由两种情况引起 :活性位被覆盖和孔被堵塞。在热重分析仪上以异丙苯裂化反应为模型反应 ,采用CCAP(恒碳Arrhenius关系图 )技术探讨了裂化催化剂ASTRA MB1的积炭失活机理 ,得到了反应速率常数和有效扩散系数随积炭量的变化规律。结果表明 ,当反应温度低于 5 73K时 ,孔的堵塞对催化剂的活性影响较大 ,当反应温度高于 6 2 3K时 ,积炭主要发生在催化剂的外表面 ,其上的活性位被覆盖是造成催化剂失活的主要原因。理论上 ,通过降低催化剂粒径以增加其外表面的活性位数目 ,是提高催化剂利用率的有效途径。
In general, deactivation of the coke of the catalyst is caused by two situations: the active site is covered and the pores are blocked. Cumene cracking reaction was taken as a model reaction on a thermogravimetric analyzer. The coke deactivation mechanism of the cracking catalyst ASTRA MB1 was investigated by the CCAP (Constant Carbon Arrhenius Diagram) technique, and the reaction rate constant and effective diffusion coefficient were obtained. Variation of carbon content. The results show that when the reaction temperature is lower than 5 73K, the clogging of pores has a great influence on the activity of the catalyst. When the reaction temperature is higher than 623K, the carbon deposition mainly occurs on the outer surface of the catalyst, and the active sites on the catalyst are covered Is the main reason for catalyst deactivation. In theory, reducing the catalyst particle size to increase the number of active sites on its outer surface is an effective way to increase the catalyst utilization.