甲乙苯脱氢制甲基苯乙烯反应工艺及动力学研究

摘要

With the industrial dehydrogenation catalyst,the ethyl toluene dehydrogenation was conducted at 580-635 ℃,30-101 kPa,water/ethyl toluene mass ratio of 2.0-4.0,and space velocity ranging from 0.5-1.5 h-1.The results indicated that the conversion of ethyl toluene increases as the temperature rises while the selectivity for methylstyrene is the opposite;increasing water/methyl toluene ratio leads to higher conversion and selectivity;the effect of reducing LHSV is the same as increasing temperature,while higher reaction pressure is in favor of both conversion and selectivity.The most optimal reaction conditions are:50 kPa,620 ℃,the water-to-reactant ratio of 2.0 and the LHSV of 0.5 h-1.The kinetics of dehydrogenation reaction of ethyl toluene was studied by using experimental data.Three possible ethyl toluene dehydrogenation reaction kinetics models were proposed in the premise of assumptive and simplified reaction network and based on the different reaction mechanisms.After the statistical test for 3 models,the two-site adsorption model was chosen as the best model,and then the parameters of the model were determined.The results can be used for the reactor design and the selection of optimal operating conditions.%使用工业脱氢催化剂,在温度580～635℃、水与甲乙苯质量比2.0～4.0、体积空速0.5～1.5 h-1、压力(a)30～l01 kPa的实验条件范围内,研究了工艺参数对甲乙苯脱氢制甲基苯乙烯反应的影响规律.结果表明:随着温度的升高,甲乙苯转化率提高,甲基苯乙烯选择性下降;随着水与甲乙苯配比的增加,转化率和选择性均上升;体积空速降低时,虽能提高转化率,但会使选择性降低;压力降低时,既可提高转化率,又有利于选择性的升高;适宜的工艺条件为压力(a)50 kPa、温度620℃、水与甲乙苯质量比2.0、体积空速0.5h-1.利用实验数据,对甲乙苯脱氢反应进行了动力学研究.假设并简化反应网络,根据不同反应机理提出3种可能的甲乙苯脱氢反应动力学模型,对模型进行统计学检验筛选后,确定双位吸附模型为最佳反应动力学模型,并估算了该模型的参数,可为反应器的设计和最佳操作条件的选择提供依据.