【摘要】 以热重分析法研究了低碳醇在几种阳离子改性HZSM-5沸石上的积炭和脱炭性质。结果表明,甲醇在氢型和交换度较小的Mn改性沸石上的积炭和烧炭性质相近。在交换度较高且具有脱氢芳构化活性的改性沸石上,甲醇生炭量多少不能与B酸量相关联,但可与芳构化活性相对应,积炭反应除通过氢转移外,还可通过直接脱氢而完成。低碳醇在Zn(2)改性沸石上积炭时,积炭量随醇分子碳数增加而减少。Cu改性沸石的积炭容易除去,宜在低温烧炭。脱氢芳构化活性高的催化剂,烧炭活化能较高,可能是因为焦的石墨化程度较高。更多还原

【Abstract】 The coking and decoking behaviours on some cation-modified HZSM-5 zeolites in the conversion of lower alcohols have been studied by means of thermogravimetric analysis. The results indicate that the properties of methanol coking over a Mn-modified zeolite are similar to that over HZSM-5. The amount of coke formation can not be correlated with the amount of B-acid,but can correspond to the activity of aromatization. This suggests that the coking reaction proceeds through a dehydrogenation pathway besides H-transfer. The coke formation from lower alcohols over a zinc-modified zeolite decreases with the increase of C-number of alcohols and the decoking rate on a Cu-modified zeolite is enhanced significantly. The parameters of decoking kinetics of various modified zeolites show that the higher the dehydro-aromatization activity of the zeolite,the higher the activation energy of decoking is. This is because of the higher C/H ratio of coke formed on it.更多还原