正丁烯骨架异构化ZSM-35分子筛催化剂的失活与再生研究

发布时间：2018-05-31 17:35

  本文选题：ZSM-35分子筛 + 晶粒　； 参考：《东北石油大学》2017年硕士论文

【摘要】：本文成功的合成了大小晶粒ZSM-35分子筛催化剂并对其进行正丁烯骨架异构化反应。结合XRD、SEM、BET、TG等表征手段,对不同晶粒ZSM-35分子筛催化剂失活现象进行分析研究。以L-ZSM-35为原粉,通过使用草酸与柠檬酸分别对L-ZSM-35分子筛进行脱铝,探究了其失活现象。考察了铝粘结剂以及硅粘结剂对L-ZSM-35分子筛失活的影响。探究了L-ZSM-35分子筛在工业条件下的失活与再生现象得到结果如下:(1)小晶粒ZSM-35分子筛显示了较好的催化性能,在WHSV=7、常压的条件下,小晶粒ZSM-35分子筛的评价时间达到146 h,异丁烯的收率超过40%、异丁烯选择性超过90%。同时,小晶粒分子筛具有较慢的积碳速度以及较大的积碳容量,积碳量可达12%以上。(2)根据分子筛失活的特点将积碳系统的分为两部分:反应第一阶段积碳和反应第二阶段积碳。尽管第一阶段积碳的积碳量比较大,占总积碳量的80%以上,但主要作用是覆盖一些非选择性的酸位点。而第二阶段积碳的积碳量比较少,约占总积碳量的20%,却是导致失活的关键。(3)当草酸处理分子筛的浓度为3 mol/L、柠檬酸处理分子筛浓度为1 mol/L时L-ZSM-35分子筛催化效果最好,异丁烯收率均超过40%、异丁烯选择性超过90%,评价时间超过65 h。脱酸处理有效的降低了分子筛的积碳量,增加了到第二阶段的积碳容量。(4)经二氧化硅粘结改性后的L-ZSM-35分子筛催,评价化效果良好,异丁烯收率均超过40%、异丁烯选择性超过90%,评价时间超过60 h。外接孔道越大,越有利于延缓分子筛失活。(5)工业丁烯中含有的致毒物质是一种永久致毒物质,会导致分子筛不可再生,且再生时间越长,再生效果越好。
[Abstract]:In this paper, large and small grain ZSM-35 molecular sieve catalysts were successfully synthesized and isomerization of n-butene was carried out. The deactivation of ZSM-35 molecular sieve catalysts with different grains was studied by means of XRDX SEM-BETTG and other characterization methods. The dealination of L-ZSM-35 molecular sieve was investigated by using oxalic acid and citric acid as raw powder. The effects of aluminum binder and silicon binder on the deactivation of L-ZSM-35 molecular sieve were investigated. The results of deactivation and regeneration of L-ZSM-35 molecular sieve under industrial conditions were as follows: (1) small grain ZSM-35 molecular sieve showed good catalytic performance. The evaluation time of small grain ZSM-35 molecular sieve is 146h, the yield of isobutene is more than 40 and the selectivity of isobutene is more than 90. At the same time, the small grain molecular sieve has a slow carbon deposition rate and a large carbon accumulation capacity, which can reach more than 12%.) according to the characteristics of molecular sieve deactivation, the carbon deposition system is divided into two parts: the first stage of the reaction and the second stage of the reaction. Although the carbon accumulation in the first stage is relatively large, accounting for more than 80% of the total carbon deposition, the main function is to cover some non-selective acid sites. However, in the second stage, the carbon deposition was relatively small, accounting for about 20% of the total carbon deposition, but it was the key factor leading to inactivation.) when the concentration of oxalic acid was 3 mol / L, the citric acid concentration was 1 mol/L, the catalytic effect of L-ZSM-35 zeolite was the best, and the catalytic effect of L-ZSM-35 zeolite was the best when the concentration of oxalic acid was 3 mol / L and citric acid was 1 mol/L. The yield of isobutene was over 40, the selectivity of isobutene was over 90, and the evaluation time was over 65 h. The deacidification treatment can effectively reduce the carbon accumulation of molecular sieve and increase the carbon accumulation capacity of the second stage. The L-ZSM-35 molecular sieve modified by silica binds is used to catalyze the molecular sieve, and the evaluation effect is good. The yield of isobutene was over 40, the selectivity of isobutene was over 90 and the evaluation time was more than 60 hours. The larger the external pore channel, the more favorable to delay the deactivation of molecular sieve. 5) the toxic substance contained in the industrial butene is a permanent toxic substance, which will lead to the non-regeneration of molecular sieve, and the longer the regeneration time, the better the regeneration effect.
【学位授予单位】：东北石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36;O623.121
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本文编号：1960708