Process and plant for producing c2-c4 olefins from methanol and/or dimethyl ether with increased yield

Abstract

A process and a plant for producing C-Colefins, in particular propylene, from an educt mixture containing steam as well as methanol vapor and/or dimethyl ether vapor. The educt mixture is reacted in at least one first reactor on a granular, form-selective zeolite catalyst to obtain a reaction mixture including low-molecular olefins and gasoline hydrocarbons, which in a first separating device is separated into a mixture rich in C-Colefins, a mixture rich in Cgasoline hydrocarbons, and an aqueous phase, wherein the mixture rich in gasoline hydrocarbons is mixed with an inert medium, the mixture thus obtained is reacted in at least one second reactor on a granular zeolite catalyst to obtain a product mixture including C-Colefins, and this product mixture is recirculated to the first separating device, and wherein the mixture rich in Cgasoline hydrocarbons is separated in a second separating device into a product stream containing C-Chydrocarbons and a product stream containing Chydrocarbons, before being supplied to the second reactor, and only the product stream containing Chydrocarbons is supplied to the second reactor, whereas the product stream containing C-Chydrocarbons together with the educt mixture is supplied to the at least one first reactor.