Olefin separation device and methyl alcohol system alkene system that includes it

The utility model provides an olefin separation device and methyl alcohol system alkene system that includes it. This olefin separation device includes demethanizer, deethanizer and propylene rectification plant, and wherein, demethanizer includes propane feed inlet and material export, deethanizer's matter entrance is connected through first pipeline with the export of demethanizer's material, propylene rectification plant's matter entrance is connected through the material export of second pipeline with deethanizer, and propylene rectification plant's material export is connected with the propane feed inlet through the third pipeline, and the olefin separation device still includes the fourth pipeline, fourth pipeline one end and deethanizer's material exit linkage, and the other end is connected with the propane feed inlet. This olefin separation device is before propylene rectification unit establishs the circulation, and three components in the carbon are passed through the fourth pipeline and are got in