Simulation And Optimization Of Separation Process For One-step Synthesis Of Dimethyl Ether From Syngas

Dimethyl ether can be used as a new multipurpose clean green energy, and itsproduction and development has been received a great deal of attention in chemicalengineering field. Process of one-step synthesis of dimethyl ether from syngas hasadvantages such as material economic and easy, flexible operation, high CO singlepath conversion,short process, low investment and low energy consumption comparedwith traditional two-step dimethyl ether synthesis,and it has became the focus ofresearch at home and abroad at present. Simulating and analyzing the productionprocess of one-step synthesis of Dimethyl Ether from syngas，thinking about theanalysis of the absorbent choice, using modern technology optimization process twoaspects at the same time, a novel dimethyl ether production technology is presentedwhich is high purity, high selectivity, low energy consumption step.The main content of the thesis, method of the research and the main resultsinclude the following:（1）Considering the characteristics of material flow from the reactor of one-stepsynthesis of dimethyl ether from syngas systematically, With the method of processsystem engineering process is contained in the absorption and distillation separationsequence of unit operations such as research, developed the first absorption afterdistillation separation process, for the whole process of integrated process providestheoretical guidance system method.To research the distillation separation sequenceof The process flow which contains the absorption and distillation, developed thedistillation after absorption separation process,to provide theoretical guidance systemfor the whole process of integrated process.（2）The energy consumptions of the absorber with different absorbents-methanol and water, are simulated and compared using Aspen Plus. The results showthat using the water as the absorbent is more energy efficient, reducing the total heatload by23.54%and the total cooling load by35.97%compared with using themethanol as the absorbent. The separation process are simulation calculated and system optimized，Determines the optimal operating conditions of different refluxratio, plate number of the tower and feed position, accordingly, get a optimalprocess operating conditions.And determine the load of condenser and reboiler andthe total energy consumption of the separation process.（3）From the perspective of energy saving, two-column and Multi-effectdistillation separation processes are proposed according to different separationobjectives. The results show that compared with the original production process thetwo-column separation process of methanol and water can increase the dimethyl etherproduction by11.50%, without significant change in the energy consumption.Furthermore, the three-column distillation process can reduce the cooling load by45.07%and heat load by19.27%. In the meantime the Dimethyl Ether production isincreased by11.15%. The energy-saving effect is remarkable.Compared withtwo-column distillation process,the three-column distillation process can reduce thecooling load by45.32%and heat load by20.13%. In the meantime the DimethylEther production is increased nonobvious. Compared with two-column and theoriginal production process the Multi-effect distillation separation processes is notonly obtain higher DME yield greatly,but also reduce energy consumption.In short, ithas high industrial application value.（4）Simulating and calculating the production annual output of300,000tonsprocess of one-step synthesis of Dimethyl Ether from syngas.Designing thepre-column C103detailedly,and get the size of tower equipment.Taking condenser ofthe C106separation column as an example, using industrial heat ExchangerExchanger Design and Rating V7.3which is developed newly by Aspen softwareAspen Tech company carries on the simulation design, to get the device parameterssuch as size of the heat exchanger.