Separation processing method for a product stream of a dimethyl ether reactor

Abstract

A method for the processing, by separation technology, of a product stream (g), containing at least dimethyl ether, methanol, water, carbon dioxide, carbon monoxide and hydrogen, from a reactor () used for the synthesis of dimethyl ether (z) from synthesis gas (e), is proposed. The product stream (g) is fed, in at least partially gaseous form, into an absorption column () operated with a liquid reflux, a gaseous top stream (m) being removed from the absorption column () at the top and a liquid sump stream (p) being removed at the bottom. The sump stream (p) is at least partially fed into a first distillation column (), a gaseous transfer stream (q) containing dimethyl ether and a stream (r) predominantly containing methanol and/or water being removed from the first distillation column (). The top stream (m) is at least partially cooled initially to a first temperature level and subsequently further cooled to one or more further temperature levels, a first condensate stream (n) being formed after the cooling to the first temperature level and one or more further condensate streams (s, t) being formed after the further cooling to the further temperature level or levels. The first condensate stream (n) is partially used to form the liquid reflux and the further condensate stream or streams (s, t) is or are at least partially fed into a further distillation column (), from which a liquid stream (z) predominantly containing dimethyl ether and poor in or free from carbon dioxide is removed at the bottom. The invention also relates to a corresponding separation apparatus and an apparatus () for producing dimethyl ether.