HZSM-5择形催化剂上乙苯烷基化反应生产对二乙苯的研究

针对乙苯与乙烯烷基化法生产对二乙苯的工艺过程,利用1 500 t/a对二乙苯的工业装置,对装有镁改性HZSM-5分子筛的固定床反应器中的乙苯烷基化反应工艺条件进行了研究。考察了反应温度、空速和原料质量比对反应的影响,并进行了分析和讨论。结果表明,在不同的工艺条件下,产物中邻、间二乙苯的质量分数均随对二乙苯的质量分数升高而升高,但间、邻二乙苯质量分数过高,增加了产品分离的难度,很难得到高纯度的对二乙苯产品。乙苯的转化率及反应产物中邻、间、对二乙苯的质量分数均随着反应温度的升高,在保证产品质量的前提下,375℃为适宜的反应温度。在乙苯循环反应过程中,乙苯质量空速应在3 h-1左右,同时乙苯与乙烯的原料质量比不宜过大,在17左右适宜。

Study on alkylation of ethylbenzene to P-diethylbenzene on HZSM-5 shape-selecting catalyst

Aiming at the technological process of the alkylation reaction of ethylbenzene and ethylene to p-diethylbenzene,the operating conditions of the alkylation reaction in a fixed-bed reactor charged with Mg modified HZSM-5 molecular sieve were studied in an industrial installation of product capacity 1 500 t/a p-diethylbenzene.The influence of temperature,void speed and reactant mass ratio on reaction were experimentally investigated,respectively.The results at different operation conditions were analyzed and discussed.The mass fraction of o-diethylbenzene and m-diethylbenzene at various operating conditions increase simultaneously with that of p-diethylbenzene.This is not a desirable result because higher mass fraction of o-diethylbenzene and m-diethylbenzene makes more difficulty of production separation,consequently,leading to the difficulty to attain highly pure p-diethylbenzene.The fractional conversion of ethylbenzene and the mass fractions of o-diethylbenzene,m-diethylbenzene and o-diethylbenzene in reaction production increase with temperature rise.375 ℃ is a suitable reaction temperature to ensure production quality.In the process of cycle reaction of ethylbenzene,the fitting void speed of ethylbenzene is about 3 h1,and the mass ratio of ethylbenzene to ethylene can not be too high,17 is a fit value.