The invention discloses a
separation method for a
reaction product of
propane dehydrogenated propylene preparation and belongs to the field of
petrochemical industry. The method comprises the following steps: (1) the
reaction product of
propane dehydrogenated propylene preparation is pretreated, then, the pretreated
reaction product enters a propylene and
ethylene cascaded
refrigeration system with an expander, and then, a
liquid phase is fed to a deethanizer; (2) top oil gas of the deethanizer is condensed and then enters a
reflux tank of the deethanizer, tank bottom liquid of the
reflux tank of the deethanizer totally returns to the deethanizer, tank top gas of the
reflux tank of the deethanizer enters a top condensation section of the deethanizer and is fractionated by the condensation section, and top gas of the condensation section is condensed by a refrigerator of the top condensation section of the deethanizer under the action of a propylene refrigerating
system and then enters a
deep freezing tank of the deethanizer; (3) tank top gas of the
deep freezing tank of the deethanizer is delivered out of a device as
fuel gas, and bottom liquid of the deethanizer enters a propylene refiner; and (4) a refined propylene product is fractionated from the top of the propylene refiner, a bottom
liquid phase of the propylene refiner enters a depropanizer, and a bottom product C4+
cut of the depropanizer is delivered out of the device. By adopting the
separation method, the problems, i.e., large absorbent circulating rate and
high energy consumption in the prior art can be solved.