DEVELOPMENT OF A SYSTEM OF AUTOMATIC MOBILE CONTROL OF THE DISTILLATION PROCESS

Abstract

Subject. System of automatic mobile control of distillation process. Objective. Improving the productivity and energy efficiency of the distillation process by developing an automatic control system that provides mobile control effects on the process, as well as the study of transients in the developed system during major disturbances. Tasks. Development of a system of automatic mobile control of the distillation process, calculation of transients in the developed system, definition and evaluation of quality control indicators. Methods. Methods of simulation digital modeling of automatic control system operation. Results. A system of automatic control of the distillation process has been developed, which provides for discrete and continuous mobile control actions. Discrete effects are changes in the point of introduction of feed into the column; continuous – in changing the ratio of the flow rates of feed flows supplied to the upper and lower parts of the installation. Traditional control effects are also used by changing the heat carrier flow rate in the cube evaporator and irrigation. Optimal traditional and mobile control effects are calculated by the computing control device according to the normalized criterion using a nonlinear predictive model and are realized by influencing the actuators on the supply lines of feed flows, irrigation in the column and the heat carrier in the evaporator. The system involves the use of an adequate mathematical model, for which its periodic identification is performed and the process is monitored by additional measurement of the temperature profile of the column, temperature and pressure on the control plate. In order to maintain the material balance in the liquid and steam phases, it is planned to stabilize the pressure at the top of the column, the levels in the distillate and the cubic product receivers by changing the flow rates, of refrigerant to the condenser, distillate and cubic product. Using the example of a distillation column for separating a methanol-water mixture, the operability of the proposed automatic mobile control system is studied by digital simulation methods. The disturbances consisted of changes in the flow rate, composition, and temperature of the feed. Conclusions. It is proved that the use of the developed system allows to increase the technical and economic indicators of the distillation process and to improve the quality of management. The results can be used in the chemical, petrochemical, oil refining, food industries to control and optimize the processes of binary, multicomponent distillation.