Process Simulation And Thermodynamic Study Of Synthesis Of Ethylene Glycol With Coal Based Syngas

Ethylene glycol(Ethylene glycol referred to as EG)is an important organic chemical raw material.It has been widely used in the synthesis of polyester resin,antifreeze,plasticizer,nonionic surfactant and coating ink and other chemical products.China’s ethylene glycol self-sufficiency rate has been at a low level for a long time,while with the increasing demand for EG in recent years,scientific researchers focus on the research and development of new synthetic EG technology.According to the present situation of fossil energy in China,The development of coal based syngas for ethylene glycol process is not only in line with China’s reality,but also in line with the clean production process of C1 chemical industry.In order to optimize the process and preparation of polyester grade ethylene glycol,this paper is based on the process of coal based synthesis of ethylene glycol,using Aspen simulation software to simulate and optimize the process for preparing ethylene glycol from coal based syngas.The vapor liquid equilibrium data of the azeotrope system(ethylene glycol(EG)+ 1,2-butanediol(1,2-BD))and(1,2-BD+DIBK(azeotropic agent))were determined by using vapor-liquid equilibrium apparatus.The results showed as that:(1)The vapor liquid equilibrium data of DIBK+1,2-BD,and EG +1,2-BD binary system were measured by using an improved vapor-liquid equilibrium apparatus.The composition of equilibrium data was determined by chromatography.The results showed that there was the boiling point between ethylbenzene + EG and DIBK +1,2-BD binary system.The content of DIBK at the boiling point increases with the decrease of pressure.The experimental data are in good agreement with the thermodynamic consistency test.Using Aspen simulation software,the interaction parameters of Wilson,NRTL and UNIQUAC activity coefficient models were associated with two parameters,respectively.Through simulation,the theoretical value is consistent with the experimental data.By simulation,the theoretical value is consistent with the experimental data.It is shown that the activity coefficient models of Wilson,NRTL and UNIQUAC are suitable for DIBK +1,2-BD and EG +1,2-BD two system.(2)In order to further study and understand the process of producing ethylene glycol from coal based syngas,the coupling regeneration section,DMO refining section,hydrogenation section and EG refining section were simulated and analyzed in detail.In order to determine the optimal operating parameters of each module,the sensitivity analysis of the basic operating parameters of the flash tank and the distillation column were carried out.The high purity water was produced in the coupling regeneration section,and the DMO content of the refined DMO was 1,and the quality and yield of the byproduct(DMC)was 97.8%.In the EG refining section,the yield of EG,Ethanol and 1,2-BD are 280kt/a,10kt/a and 15kt/a,respectively.Their quality are 99.9%,97.9%and 100.0%,respectively.(3)The MN regeneration reaction was replaced by reactive distillation.The results show that the gas phase and liquid phase can be separated directly,and the unreacted methanol can be used as circulating material,and the separation of methanol and The separation of azeotropic system of methanol +dimethyl carbonate(DMC)was omitted.It is not difficult to see that the reactive distillation process not only reduces the energy consumption of methanol,but also eliminates the DMC azeotropic refining system.