| SCR flue gas denitration control is an important means to reduce NOx emissions and ensure the efficiency of denitrification.In recent years,with China’s industrial modernization level and continuous development of economic,the capacity of thermal power generating unit is continuously increasing,the load changes more and more quickly,environmental protection requirements is continuously improving and the control requirements of SCR flue gas denitration become more stringent.The basic principle of SCR flue gas denitrification system is introduced.The several control strategies of SCR flue gas denitrification system are analyzed.Then,the model of each link of the ammonia flow control system is deduced,the mathematical model of the ammonia flow control system is established and a perturbation analysis of the model is implemented.Based on the established model,two kinds of control schemes of traditional PID control are simulated and the adjustment range of the controller parameters is given.By combining the characteristics of fuzzy control and the advantages of PID control and the actual production experience,the fuzzy control rules are formulated.Above all,a kind of control scheme which combines fuzzy control with integral adjustment is designed and the control performance of the fuzzy control method is improved by comparing the simulation results with the traditional PID control.Finally,a new variable universe expansion function is proposed by combining with the variable universe fuzzy control based on the idea of not changing the fuzzy control rules of the number of cases,through the method of domain adjustment along with the change of error,to improve the control quality of the fuzzy controller.A simulation is implemented by recommending it to the fuzzy controller.The results show that the control scheme has good control quality. |
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