Development And Simulation Of Recycle 1,2-dichloro Etane Chlorination Low-boiling Removing Process In Vcm Plant

In oxychlorination producing vinyl chloride monomer (VCM) plant, a small quantity benzene, chloroprene and other unsaturated hydrocarbons turn out as byproduct in ethylene dichloride (EDC) cracking unit. Benzene is inhibitor of EDC cracking. Because its boiling point is the same to EDC, it is difficult to remove benzene in normal EDC refining unit. Chloroprene with a very reactive chemical property could self-polymerize in VCM plant to block equipments and pipes. It is of great significance and realistic meaning to develop a process which can reduce the contains of benzene and chloroprene for a 200 thousand tons per year VCM plant.First of all,a macro reaction kinetic of benzene chlorination in VCM plant which is based on power function kinetic model was proposed. Benzene chloride experimental data that summarized from references were supplemented by regressing functions of trend of benzene and chloroprene concentration changing with time. Using these data, parameters of macro reaction kinetic were regressed. The form of kinetic is 11945-r_B =59.4665 exp(-24295.4/RT)C_B^0.4796C_Cl¹¹⁹⁴⁵ Using obtained macro kinetic to calculate a benzene chlorination reactor constructive parameters which in another VCM plant and compare with its actual values. The results illustrated that calculated values and actual values fit well. This macro kinetic can be used to calculate benzene chlorination reactor in VCM plant.A recycle EDC chlorination low-boiling removing process was determined for 200 thousand tons per year VCM plant. Recycle EDC flow from VCM refining unit was divided into two parts. One part was sent to benzene chlorination reactor in which occur benzene chlorination reaction with chlorine. Flows from benzene chlorination reactor and the other part of recycle EDC flow were sent to chloroprene chlorination reactor occur chloroprene chlorination reaction with chlorine. Flows from chloroprene chlorination reactor were sent to EDC refining unit for removing chlorided benzene and chloroprene. The constructive parameters and operation conditions of main equipments in this process were determined.On the basis of simulating 200 thousand tons per year VCM plant, the contains of benzene and chloroprene in VCM plant after adding recycle EDC chlorinaion low-boiling removing process were studied. The results proved that the amount of benzene and chloroprene in VCM plant reduced obviously and quality of VCM was not affected. The applicability of adding recycle EDC chlorination low-boiling removing process in the 200 thousand tons per year VCM plant was studied. The results proved that equipments like towers and heat exchangers were still could satisfy the need of operation.