Simulation Study Of Ethylene Cryogenic Separation Unit

Cryogenic separation unit plays an important role in an ethylene plant.Supplied cooling by several refrigeration compressors and low temperature recovered streams,charge gas is cooled down and condensates in this unit.As there are many related equipments and streams,cryogenic separation unit has the most complicated technological process in an ethylene plant.As the result of several expansion projects,the cryogenic separation process of Yanshan Ethylene Plant has become even more complicated and more difficult to be operated.The cryogenic separation unit model was set up with ASPEN PLUS,and the refrigeration compressors and the cold boxes are deeply studied.In the end,the following results have been obtained.For single component refrigeration compressors,several energy-saving technologies are usually used during process design,such as appropriate temperature gradient,super-cooling,heat pump and step-by-step depressurization;For binary components refrigeration compressors,the properties of binary cryogen has been studied.The results show that every component has it particularly function and optimum content.The simulation results of the cold boxes showed that both the minimum approach temperature and the thermal equilibrium affect the operation of the cold boxes.