Research On The Simulation Of Separation And Recovery Of Mixed Alcohols Fro Production Of Ethylene Glycol Produced By Coal

Ethylene glycol(EG)is the main raw material for the production of polyester fibers and antifreeze solution.It has a large demand in China.A lot of organic wastes will be produced from the production of ethylene glycol produced by coal.Research on the simulation of separation and recovery of mixed alcohols is presented in this paper.Simulation calculation of steady-state and optimization of process parameters of distillation column were carried out by Aspen Plus process simulation software.At the same time,dual-effect distillation technology was used to optimize the energy of methanol recovery column,which reduced the energy consumption in the process.In this paper,the vapor-liquid equilibrium models of methanol-water,methanol-ethylene glycol and ethylene glycol-water systems are studied.The NRTL,WILSON and UNIQUAC activity coefficient models were selected.The binary interaction parameters of the above systems were fitted and correlated by Aspen’s data regression.By comparing the deviation between the experimental data values and the calculated values of the model,the results show that the NRTL equation can well describe the methanol-water and methanol-glycol systems,while the ethylene glycol-water system is suitable for the UNIQUAC equation.The simulation of steady-state of dehydrogenation column,methanol recovery column,ethanol recovery column and ethylene glycol recovery column was carried out by process simulation software.The optimal process parameters of each column were determined by single factor method and multi-factor orthogonal test method.The theoretical stage number(NT),feed stage position(NF),the mass reflux ratio(RR),and production(D/B)are as follows.C-101:30、6、1.8、280 kg/h,C-102:65、18、6.5、1260 kg/h,C-103:35、18、2.6、309 kg/h,C-104:12、8、0.02、1640.3 kg/h.The amount of recovered methanol with 99.5%purity is 1260 kg/h,and the amount of recovered ethylene glycol with 99%purity is 1640.3 kg/h.The purity of the product can meet the industry requirements.The energy-saving optimization of methanol recovery column was carried out by means of cocurrent and countercurrent dual-effect distillation.The calculation results show that the energy consumption of cocurrent dual-effect distillation is smaller than that of countercurrent distillation.Compared with single-column distillation,the annual saving of circulating water is about 1.83 million tons,the steam is about 0.0202 million tons,the utilities can be saved by 3.3962 million yuan/a,the total energy consumption can be saved by 3135.14 kW.The total annual cost was reduced by 3.2216 million yuan,and the effect of energy saving was remarkable.