TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: The first separation tank has operation pressure of 0.01-4.0 MPa, preferably 0.1-2.0 MPa and operation temperature of - 100-30 degrees C, preferably - 80-10 degrees C. The second separation tank has operation pressure of 0.01-4.0 MPa, preferably 0.1-2.0 MPa and operation temperature of - 130-0 degrees C, preferably - 110 to - 20 degrees C. The third separation tank has operation pressure of 0.01-4.0 MPa, preferably 2.0-4.0 MPa and operation temperature of - 170 to - 30 degrees C, preferably - 160 to - 60 degrees C. The fourth separation tank has operation pressure of 0.01-4.0 MPa, preferably 2.0-4.0 MPa and operation temperature of - 180 to - 40 degrees C, preferably - 170 to - 70 degrees C. The fifth separation tank has operation pressure of 0.01-4.0 MPa, preferably 2.0-4.0 MPa and operation temperature of - 190 to - 50 degrees C, preferably - 180 to - 80 degrees C. The sixth separation tank has operation pressure of 0.01-4.0 MPa, preferably 2.0-4.0 MPa and operation temperature of - 200 to - 60 degrees C, preferably - 190 to - 90 degrees C. The low carbon olefin material flow is removed with carbon monoxide via carbon monoxide copper series catalyst or C18 catalyst. The low carbon olefin material flow is removed with oxygen via nickel series deoxidation catalyst or preferably manganese series deoxidation catalyst. The dewatering or drying operation for low carbon olefin material flow uses 3 Angstrom molecule sieve. The alkali washing and water washing operation for the low carbon olefin material flow is realized in alkali washing tower, where the lower part of the alkali washing tower is the alkali washing section for alkali washing while the upper part of the alkali washing tower is the water washing section for water washing, and the water is guided from the upper part of the water washing section. The alkali liquid is guided from the upper part of the alkali washing tower. It is sodium hydroxide water solution having a concentration of 0.001-50 wt.% or potassium hydroxide water solution having a concentration of 0.001-50 wt.%. The operation pressure at the top of the deethanization tower is 2.0-4.0 MPa; and the temperature at the bottom of the deethanization tower is - 50-60 degrees C. The operation temperature of the refluxing tank of deethanization tower is - 160 to - 60 degrees C, preferably - 150 to - 70 degrees C; and the mol refluxing ratio is 0.01-40. The deethanization tower has 30-60 pieces of theoretical plates. The operation pressure of ethylene rectifying tower is 0.01-2.0 MPa, preferably 1.1-1.8 MPa; and the temperature at the top of ethylene rectifying tower is - 50-50 degrees C, preferably - 30-30 degrees C. The operation temperature of the refluxing tank of ethylene rectifying tower is - 60 to - 10 degrees C, preferably - 50 to - 20 degrees C. The operation pressure at the tower top of propylene rectifying tower is 0.01-2.0 MPa, preferably 1.0-1.7 MPa; and the temperature at the bottom of propylene rectifying tower is 10-100 degrees C, preferably 30-70 degrees C. The operation temperature of the refluxing tank of propylene rectifying tower is 10-80 degrees C, preferably 20-70 degrees C; and the mol refluxing ratio is 0.1-40.