An improved methanol-to-olefin (MTO) product recovery scheme is provided
which enables substantial reduction in the amount of light olefins that
are undesirably captured in a dimethylether (DME) recycle stream when a
portion of the methanolic feed to the MTO reaction zone is used as the
scrubbing solvent in a primary DME absorption zone in order to recycle
this DME oxygenate by-product to the MTO reaction zone. In accordance
with the present invention, a liquid solvent stream recovered from the
primary DME absorption zone is subjected in a stripping zone to light
olefin stripping conditions sufficient to lift a substantial portion of
the light olefins that are absorbed in the DME solvent without stripping
a significant portion of this methanol solvent, thereby increasing the
recovery of desired light olefins while simultaneously diminishing the
amount of light olefins carried by the DME recycle stream back to MTO
conversion step.