Research On Washing Tower Temperature Control System Of Shale Oil Refining Factory

As the shortage of traditional resources is becoming more and more serious, the industry of shale oil refining will have an unprecedented development and prospect. In the industry of shale oil refining, the hydrocarbon vapors separated from the raw ore can be deeply fractionated only after having been washed and filtered. The control effect of the washing tower directly affects the quality of the shale oil, what’s more, the temperature control is the key point of the washing tower control system. Therefore, it’s necessary to have a further research on the temperature control of hydrocarbon vapors in washing tower.Based on the production line of the shale oil refinery, this thesis expatiates on the inner structure and the industrial art of the hydrocarbon vapors washing tower. By researching and analyzing the process of the system, the thesis selects the outlet temperature of recirculation region as the controlled variable. Because the production process of the washing tower is very complicated and the controlled object has the characteristics of nonlinear and time-varying, it is difficult to build an accurate mathematical model. Thus, according to the object properties and the empirical data, the thesis builds an approximate mathematical model. The thesis analyzes in detail the control processes and effects of the single loop PID control system and the cascade PID control system. According to the uncertainty of the object model, the Fuzzy PID controller is proposed to replace the PID controller of the main loop in cascade control system in this thesis. This not only can keep the advantages of the simple structure and highly adaptable in PID controller, but also can adjust PID controller parameters online for adapting to the changes in the controlled object parameters. So that the highly control effects will come true. This thesis details the design process of the Fuzzy PID controller.Finally, compared with the simulation results of the cascade control system under the two different methods, it turns out that the Fuzzy PID cascade control system designed in the thesis has small overshoot, short adjustment time, better adaptability to temperature variation, strong anti-interference capacity and better control results.