Simulation Of Separation Process Of Ethylene Glycol From Coal Based Syngas

With the shortage of oil resources,the current development of a carbon chemical industry to replace the oil route to produce chemical products.The synthesis of ethylene glycol from syngas is one of the most important technologies in the chemical industry.Therefore,the use of synthetic gas to ethylene glycol not only meets the demand for ethylene glycol in china,but also conforms to the characteristics of china's resources.In the process of producing ethylene glycol,a plurality of separation processes are involved,including dehydration process,separation process of methanol-dimethyl carbonate and ethylene glycol refining process.In this paper,Aspen Plus software was used to simulate the separation process.The results are as follows:(1)The design parameters of dehydration tower are obtained by the method of simple and strict calculation.The number of theoretical plates is about 18,and the position of the feed plate is the 10th plates.The reflux ratio is about 0.56.After simulation,the mole fraction of the bottom water reaches 0.9994;(2)In this paper,the separation of methanol-dimethyl carbonate was separated by extractive distillation with dimethyl oxalate as extractant.By using the vapor-liquid equilibrium data for the system,the parameters of the model are regressed by Aspen Plus software,and then applied to the simulation.The dividing wall column was used to separate the binary system of methanol-dimethyl carbonate,and compared with the conventional model of the two Towers,recovery of dimethyl carbonate recovery rate was 83.59%when used the conventional two Towers model,for the dividing wall model,the recovery rate reached 98.52%,increased by 15.2%compared,and in terms of energy consumption reduction about 60%;(3)Simulation design of separation the binary system of ethylene glycol-1,2-butanediol and ethylene glycol-1,2-propylene glycol.Diisobutyl ketone and ethyl benzene were used to separate 1,2-butanediol and 1,2-propanediol,respectively.The model of interaction parameters of ethylene glycol-1,2-butylene glycol and diisobutyl ketone-1,2-butanediol were founded in the software database.So,in this paper,the improved double circulating vapor-liquid device was used to measure the vapor-liquid equilibrium(VLE)data for the binary system,and correlated the interaction parameters.By simulation,for the diisobutyl ketone-1,2-butanediol system,the maximum relative deviation of temperature was 0.21,the maximum relative deviation of vapor mole fraction was 0.0046,for the ethylene glycol-1,2-butanediol,the maximum relative deviation of temperature was 0.01397,the maximum relative deviation of vapor mole fraction was 0.008245,the theoretical value was consistent with the experimental data.The results show that Wilson,NRTL and UNIQUAC activity coefficient model is suitable for DIBK +1,2-BD and EG +1,2-BD.The purification process of ethylene glycol was simulated,and the recovered methanol was added into the regeneration reaction tank of methyl nitrite.The final production of ethylene glycol flow rate was 607.81Kmol/h,and the recovery rate reached 99.99%.(4)The energy of the process was analyzed by energy analyzer,and the pinch point temperature was obtained.Based on the minimum heat transfer area to optimize the heat exchanger network,the final result as followed:the number of heat exchanger number is 51;the shell number is 328;the heat exchange area is 1.393*105m2.