The 6-effect countercurrent alumina evaporation process is actually a multivariable nonlinear system where the coupling between circuits is strong.A dynamic model is presented in the vicinity of the operating point in steady state,based on material balance and thermal equilibrium.Then,the NMPC strategy is applied to the simulation of the evaporation system to solve the NMPC optimization problem better.A genetic algorithm is introduced to calculate the control sequence,and the constraint on the output variab...