The invention discloses an SCR
denitrification control method based on variable-constraint multi-
model prediction control. The method is implemented by combining a multi-
model prediction control algorithm, an intelligent model weighing
algorithm and variable constraint conditions. The method comprises the following steps that 1, a precise
NOx prediction model is obtained through the intelligent model weighing
algorithm; 2, the optimal real-time
ammonia demand is calculated by beans of
continuous rolling optimization of the multi-
model prediction control algorithm and the constraint conditions changing by following the working conditions. According to the method, the conflict generated between the model precision and the
control algorithm when an existing prediction control strategy is applied in an SCR
denitrification system is solved; compared with a traditional simple multi-linear-model linear weighing method, the model precision of the
algorithm is improved; traditional immobile constraint conditions are changed into the variable constraint conditions changing by following the working conditions, constraint adjustment is more accurate, therefore, the computing burden of a resolution control instruction is reduced, a project is easy to implement, the large
lag characteristic of the SCR
system is overcome, and the
NOx concentration regulation quality is significantly improved.