By analyzing the cause of large delay in ammonia spraying control in SCR reactor

the fuzzy self-adaptive Smith cascade control system was applied.In this method

the Smith cascade controller is used to predictively control the spraying ammonia flow and the fuzzy rules are used to adjust the PID parameters online.So the controller can adapt to changes of the control object effectively.Comparison between the fuzzy self-adaptive Smith cascade control system and the conventional PID cascade controller was carried out by simulation testing.The results show that

the control effectiveness of this Smith cascade controller was superior to that of the conventional PID cascade controller

and good control performance can be maintained when the model of control object changed

indicating the Smith cascade controller has strong adaptability.