Process and plant for the recovery and utilization of higher olefins in the olefin synthesis from oxygenates

摘要

A process and a plant for producing olefins from oxygenates such as methanol and/or dimethyl ether are proposed, in which initially the oxygenates are converted to a primary product containing propylene, other olefins, paraffins and aromatics in an olefin synthesis reactor. The primary product is separated into hydrocarbon fractions of different C chain length, wherein short-chain olefins such as propylene are obtained and beside further fractions there is also obtained a C₇₋ fraction which contains C₅/C₆ olefins, as well as a C₇₊ fraction which contains aromatics. From the latter, the aromatics are separated and alkylated with the C₅/C₆ olefins to obtain alkyl aromatics. The same are hydrogenated completely and recirculated to the olefin synthesis reactor, where they likewise are converted to short-chain olefins.