Selective catalytic reduction(SCR)flue gas denitration system has characteristics of large inertia and large delay

the conventional PID controller is not well suited for the system.To solve this problem

combing with the actual operation data of a thermal power unit

a model for SCR flue gas denitrification system based on subspace method was established.Comparison between the calculated results and the measured data verified this model has strong robustness.Moreover

the state space model of the denitration system identified by the subspace identification was transformed

and the augmented model was obtained.Then

the predictive controller based on the augmented model was designed

and the results simulated by the predictive controller were compared with that by the conventional PID controller were compared.The results show this predictive controller can track the denitration system expectations well

and has better control effect.