PROCESS FOR PREPARING ETHYLENE AND/OR PROPYLENE AND AN ISO-OLEFIN-DEPLETED C4 OLEFINIC PRODUCT

摘要

The present invention provides a process for preparing ethylene and/or propylene and an iso-olefin-depleted C4 olefinic product, comprising the steps of: a) providing a C4 hydrocarbon stream, comprising normal olefins and iso-olefins; b) subjecting the C4 hydrocarbon stream to an etherification process with methanol and/or ethanol wherein at least part of the iso-olefins are converted with methanol and/or ethanol to an tert-alkyl ether, and retrieving an etherification product stream; c) separating at least part of the etherification product stream into at least an ether-enriched stream and a first iso-olefin-depleted C4 olefinic product; d) converting at least part of the tert-alkyl ether in the ether-enriched stream to ethylene and/or propylene by contacting least part of the ether-enriched stream with a molecular sieve-comprising catalyst at a temperature in the range of from 350 to 1000 °C and retrieving a second olefinic product comprising ethylene and/or propylene.