Multistage process for converting oxygenates to liquid hydrocarbons with aliphatic recycle

摘要

A process for converting oxygenated feedstock, such as methanol, dimethyl ether or the like, to liquid hydrocarbons. In the primary catalyst stage the feedstock is contacted with zeolite catalyst to produce C2-C4 olefins and C5+ hydrocarbons. In a secondary catalytic stage with oligomerization catalyst comprising medium-pore shape selective acidic zeolite at increased pressure converts C3+ olefins to gasoline and/or distillate liquids. The improvement is a technique for recovering lower alkene for recycle to the primary catalytic stage.