Separation Process For The Product Of Ethylene Glycol Synthesis From Syngas

With the rising of oil price, using coal as raw material instead of petroleum to produce organic chemicals has become the main research directions, such as dimethyl oxalate and ethylene glycol systhesis from syngas. The route for EG manufacturing based on syngas with the reaction system of carbonization coupling of CO to DMO and DMO hydrogenation to EG.The outcome which includes unreactant, dimethyl oxalate and dimethyl carbonate, is cooled to condensate dimethyl oxalate, and then is scrubbed by methanol. The off-gas from the scrubber is returned to the reactor. Methanol and dimethyl carbonate however can form azeotrope, which enhances the separation difficulity. The methanol and dimethyl carbonate vapor-liquid equilibrium data was found in literature, and tested by thermodynamic consistency. Then using the PRO/II simulation software to return the binary interaction parameters as to simulate process. Analysis simulation result and experiment result to prove that the selected vapor liquid equilibrium data can be used for simulation and process design. On this basis, the methanol and dimethyl carbonate were separated by process simulation.Ethylene glycol is main product of dimethyl oxalate hydrogenation, while 1,2-butanediol is also generated by over-hydrogenation whose boiling point is very close to ethylene glycol's. Conventonal distillation therefore is difficult to separate the binary mixture of ethylene glycol and 1,2-butanediol because it takes a lot of energy. Compared conventonal distillation with extract distillation to separate ethylene glycol and 1,2-butanediol by simulation. It is inferred extract distillation is superior to conventional distillation on the operating cost and investment.