Simulation And Control Study On The Process Of Synthesizing Diethyl Carbonate Using Reactive Distillation Dividing Wall Column

It is the important tendency for chemical industry and engineering process technology to intensify distillation process and units of chemical engineering process. The exploration and application of process intensification and integration contributes to high efficiency, low energy exhausted, reducing the volume of equipment and its costs, and finally results to great economic and social benefits such as decrease of production cost, increased economic efficiency, enhancement of process security and escape from environment pollution. Reactive distillation dividing wall column (RDWC) is the application of process intensification and integration technology. The combination of Reactive distillation (RD) and dividing wall column (DWC) constitutes reactive distillation dividing wall column (RDWC), which integrate the merits of RD and DWC and can be used to improve the reactive conversion and selectivity, simplify the process flow, reduce the energy cost and equipment investment.Diethyl carbonate (DEC) which is one of the organic solvent, synthetic intermediate, and auxiliaries for textile, is widely used in industry. DEC can be decomposed into carbon dioxide and ethanol when it is discharged into the air. The conventional processes to produce DEC have demerits which cannot be overcome. The process of synthesizing DEC using DWC is secure, environment-friendly, and energy-efficient.In this thesis, taking the process of synthesizing DEC as an example, conventional process and RDWC process are simulated, analyzed and contrasted respectively. The reactive distillation column and methanol separation column in the conventional process are replaced by RDWC in DWC process. The distribution of liquid composition and temperature are contrasted between the two processes, and the effect of liquid and gas distribution ratio are investigated. The energy cost comparison between the processes confirms that DWC process is superior to conversional process on the aspect of energy cost. What's more, thermodynamic efficiency and reduced quantity discharged of carbon dioxide of the two processes are calculated and compared. The result shows that the thermodynamic efficiency of DWC process is much higher than that of conventional process and quantity discharged of carbon dioxide is also reduced.On the basis of conventional process, three-column and four-column model of DWC process are established in the simulation. The control study which is focus on three-column model is investigated to DWC process.