Process for the preparation of lower olefins

摘要

A process for the preparation of lower olefins which comprises the step (A) of separating in a high-pressure state a mixed fluid (I) containing dimethyl ether (DME) and methanol at a specified ratio into a gas component (II) and a liquid component (III), separating the gas component (II) into an off-gas and DME, and then making this DME join the liquid component (III) to obtain a liquid component (IV) containing DME and methanol at a specified ratio and the step (B) of subjecting the liquid component (IV) to depressurization and then introducing it into a reactor for the preparation of olefins to form a lower olefin fraction (V). Lower olefins are prepared from a mixed fluid (I) containing DME and methanol at a specified ratio.