Process Simulation And Optimization Of Producing 10kt/a DME By Gasified Methanol

Dimethylether (DME) ,which has many excellent physical and chemical properties for manufacturing pharmacy, dye, pesticide, spraying solvent and refrigerant, is widely used as raw materials. As a novel clean fuel, DME has a very promising future for developments. So, it is magnificent to study on the process of producing DME.The process of producing DME by gasified methanol was investigated. The separation process available was simulated and optimized with Aspen plus (Aspen Tech.). The results of simulation had a good agreement with the actual producing. Even so, the result could not satisfy the demands of design.Three separation processes of DME were designed according to the basic principle and the target of chemical separation, which contains mainly separate-absorb and rectify-separate cell. The results of the separation process simulated by Aspen plus showed that the reclaim ratio of DME from raw production was over 98%, the purity of DME 99.99%, under the optimal conditions.The best process of the three was explored. In the new process, the thermal efficiency was obviously higher than the previous. The optimal conditions of adsorption were obtained when theoretical plate number was equal to 7, the tower top temperature 47.8℃, the bottom temperature 51.8℃ and the scrubbing liquid was raw methanol (8mol/h). In the first distillation column the theoretical plate number was 17, the top and bottom temperature were 128.7℃ and 139.5℃, respectively. In the second distillation column the pressure was 8bar, and the top and bottom temperature were 40.3℃ and 143.8℃, respectively. The thermal loads were 757KW in the first distillation column and 446KW in the second distillation column.Based on stimulating and optimizing the heat exchanger networks, a new heat exchanger and heat exchanger networks which were fit into the synthesis of DME was proposed, and more energy about 362KW could be saved in the new process.