Abstract: The reasons of low temperature at deethanizer bottom and overpressure of depropanizer were analyzed by the Aspen Plus simulation. The effect of reflux ratio, C2 effluent quantity at the top of the deethanizer and the feeding position on separation efficiency of the deethanizer were investigated. An optimized model was established based on the condenser thermal load as the constraint conditions. It showed that the operation stability of the plant is improved by using the 0.35 MPa low pressure steam as the thermal resource of the reboiler to replace the chilled water.

Key words: deethanizer, Aspen Plus, simulation, analysis, optimization