Energy Saving Technology On Rectification Process Of1,2-Dichloroethane And Chloroethylene

In the rectification process of1,2-Dichloroethane and chloroethylene, simulation of Aspen Plus was applied in the process research. There were two plants in the1,2-dichloroethane refining unit, one of which was in the process of transformer thermal coupling of the double effect. Through the comparison and analysis of thermodynamic information, NRTL and SRK models were adopted in simulation. Compared the simulation result with actual operation parameters, the little difference shows the credibility of the thermodynamic model. The simulation process is reliable.The actual working condition of1,2-dichloroethane refining unit(1300unit) was studied in-deep, and some programs were proposed to enhance the product purity effectively. The results showed that the large amounts of impurities contained in the crude EDC from VCM refining unit had a critical influence on the product purity. Among them, chloroform, benzene and trichloroethylene, as the key component, should be strictly controlled to improve the purity. The sampling analysis result using GC-MS in July and October last year testified the conclusion. Besides, the product purity also can be raised through controlling the feed rate of the light-off tower, or adding nitrogen in the top of light-off tower. Now the device is running in good condition by equipment regulation and improvement, and the EDC purity is as high as99.6%.The simulation results also showed that both of the EDC and VCM units had a certain energy-saving space. The lower limits of steam capacity were proposed for keeping purity of1,2-dichloroethane and chloroethylene, based on actual production needs. Meanwhile, the best operation reflux ratio were certained to facilitate the actual equipment regulation. Compared with the actual steam cost,300unit can save steam consumption of11million RMB per year,1300unit can save1.4million RMB per year, and1500unit can7.5million RMB per year.