Method for converting alcohols to hydrocarbons

A method for converting reactant materials selected from the group consisting of lower alcohols, either derivatives thereof, oxygenates of synthesis gas and any one or a combination thereof, which process comprises:

• passing the reactant material in vaporous, liquid or mixed liquid-vapor condition upwardly through a fluid bed of zeolite catalyst particles, said zeolite characterized by a silica/alumina ratio of at least 12, a pore opening of at least 5 Angstroms and a Constraint Index within the range of about 1 to 12, at a temperature constrained within the range of about 530.degree. F. to about 800.degree. F. under pressure and space velocity conditions selected to achieve from about 40% to about 95% conversion of the reactant materials passed to the bed to olefin-enriched hydrocarbon products, said temperature constrained limits achieved at least in part by a plurality of heat exchange tubes immersed in a fluid bed of said catalyst and providing high pressure steam therein as a result of said heat exchange, said reactant material restricted in gasified bubble growth to less than 24 inch equivalent hydraulic diameter during contact with said bed of fluid catalyst particles by said heat exchange tubes or by a plurality of vertical open ended baffle tubes slotted in the wall thereof for flow of catalyst and gasiform reactant material therethrough adjacently positioned in combination with said heat exchange tubes, said reactant conversion exotherm further constrained by maintaining from 5% to 30% by weight of coke-like material on the zeolite catalyst in the reaction zone;
• maintaining a high rate of catalyst circulation from a dispersed catalyst phase above said fluid catalyst bed to a bottom portion of said bed following separation of reaction product from said catalyst passing into said dispersed phase;
• and
• recovering olefin-enriched hydrocarbon products of said conversion operation.