Study On The Control Of Temperature And Pressure For DME Synthesis Based On Fuzzy-PID

With CO and H2 supplied by coal gasification plant,the non-polluting and good combustion performance liquid fuel—DME can be synthesized. But the reaction going in the condition of high temperature and high pressure.And the reaction will releasing heat, then it is the course of heating first and cooling later. The traditional PID control is difficult to achieve the reaction temperature and pressure.So a control system which not only has good dynamic performance but also has good static performance is needed.For the complicated DME synthesis system which has multi-input, multiple output and lags, the fuzzy-PID the control strategy is chosed.For the nonlinear systems,fuzzy control has good adaptability,and can also be effective to overcome the lag, adjust quickly.So,for complex systems, the dynamic performance of fuzzy control is better. In the framework of small deviations, PID control of the steady-state performance is better.Making use of both fuzzy control and PID control, can obtain the advantages of the two control strategies.In this paper, the basic theory is fuzzy control and PID control.And then based on the system feature and some laws obtainen from experiments,the fuzzy control rules and fuzzy controller is designed.And then,with the IPC610BP,the control system for DME synthesis is completed.This system can collect the processing parameters.CoMParing with the settings, the error and the change rate of error is got.Taking them as the two input for fuzzy controller,an reasonable output will be obtained through the controller compute.The output is sent to the respective executive body to implement closed-loop control.When the error is small enough,the PID control will implement to achieve good static perfoamance.Through the fuzzy-PID control,the response time is short, going to the vicinity of the stable value quickly. The temoerature steady-state error is±1℃,namely±0.4%.The pressure steady-state error is±0.1MPa,namely±4%. The steady-state error is in the framework of the technical requirements.