ZSM-5分子筛催化下乙醇转化为液相烃

以ZSM-5,H-ZSM-5,Zn-ZSM-5为催化剂,在280～450℃范围内,乙醇在固定床反应器上转化为气相烃、液相烃和水。液相烃经GC-MS检测,主要成分是C5～9烯烃、C4～7烷烃和C6～11芳烃。实验结果表明,ZSM-5催化剂上,温度为425℃时,苯和甲苯选择性最大,分别为5.94%和24.81%;温度为450℃时,二甲苯选择性最大,为33.21%。Zn-ZSM-5催化剂上,温度为380℃时,苯和二甲苯选择性最大,分别为5.99%和37.89%;温度为450℃时,甲苯选择性最大,为24.45%。H-ZSM-5催化剂上,温度为380℃时,苯和甲苯选择性最大,分别为7.08%和27.60%;温度为450℃时,二甲苯选择性最大,为30.23%。硅铝比和反应温度对液相烃收率有显著影响,反应温度一定时,随硅铝比的增大,液相烃收率减小;硅铝比一定时,随反应温度的升高,液相烃收率先增大后减小。硅铝比为25时,ZSM-5和Zn-ZSM-5催化剂上,320℃下液相烃收率最大,分别为17.7%和13.8%;H-ZSM-5催化剂上,380℃下液相烃收率最大,为16.3%。

Conversion of Ethanol to Liquid Hydrocarbons over ZSM-5 Catalyst

The conversion of ethanol to hydrocarbons over ZSM-5,H-ZSM-5 or Zn-ZSM-5 zeolite catalysts was studied in a fixed-bed reactor in the temperature range of 280-450 ℃.The liquid hydrocarbons in the products were analyzed by means of GC-MS and the major products were C5-9 olefins,C4-7 alkane and C6-11 aromatics.On ZSM-5,the maximum selectivities to benzene,toluene and xylene were 5.94%,24.81% and 33.21% at 425,425 and 450 ℃,respectively.On Zn-ZSM-5,the maximum selectivities to benzene,toluene and xylene were 5.99%,24.45% and 37.89% at 380,450 and 380 ℃,respectively.On H-ZSM-5,the maximum selectivities to benzene,toluene and xylene were 7.08%,27.60% and 30.23% at 380,380 and 450 ℃,respectively.The yield of the liquid hydrocarbons decreased with increasing the silica-alumina ratio at a constant temperature,and first increased and then decreased with temperature rise at a constant silica-alumina ratio.When the silica-alumina ratio was 25,the maximum yield of liquid hydrocarbons was 17.7%,13.8% and 16.3% on ZSM-5,Zn-ZSM-5 and H-ZSM-5 at 320,320 and 380 ℃,respectively.