Research On Optimal Modeling And On-line Optimization Control Of Distillation

Distillation technology has been widely used over200years, while it is the most widely used and the largest energy-consuming chemical separation process in China. Molecular distillation is a new high-tech liquid-liquid separation technology which is studied for its industrial development by domestic and foreign researchers.Molecular distillation is internationally an efficient, mild physical separation technology which is adapted to thermal sensitivity material, and it has a special separation mechanism compared with conventional separation technique. Molecular distillation has been divided to different types by its structure such as falling film equipment, centrifugal equipment, etc., while the wiped-film molecular distillation has the most extensive application prospects. It’s efficiency is greatly improved because of its unique structure that there is a rotor which can revolve with high-speed in the wiped film equipment. But precisely because of this, make the internal flow process becoming extremely complex and restricting the technology of in-depth research and industrial applications.Based on the source and meaning of Molecular Distillation and research of basic theory and process mechanism the modeling which about the film thickness has been established in this paper. The experimental device used in this subject is Guangzhou Masson’s Three-Stage Molecular Distillation evaporator DCH-300. The mathematical model has been established with the first stage-wiped film distillation evaporator. Then carry out the experiments using the purified water and prove the accuracy of the model.The self-optimizing control algorithm has been used to the system in order to achieve the on-line optimal control and find the best real-time changes parameters during the process. This control algorithm has the adaptive capability for time-varying system, and the Molecular Distillation system just has the characteristic. Molecular Distillation can find the optimal operating point automatically during working time with using the self-optimizing control algorithms and also fit for continuous changing condition. And it can avoid the abuse which can only depend upon the experience value to set the process parameters before. With this control not only reduce the heating time which save the energy but also can get more pure material. Finally, set the DCS control system base on PLC with using the principle of DCS.