Optimal operation mode switching of dividing wall distillation based on model-predictive control

Dividing wall distillation(DWC) column is becoming a new standard of separating and purifying multivariate mixed liquid, because of DWC represents that forced operation will play a role in separation technology, which have high energy efficiency and compact structure. DWC is composed of a lot of equipments of diversified configurations, so it is complicated to operate process and requirements for specific or advanced control system technology. When operation objectives of DWC need to be online conversion, operation will be not smooth, etc. In order to solve these problems, we used two-layer control structure. The bottom layer was basic control layer(PID) and model-predictive control(MPC), and the top layer was predictive functional control(PFC) or fast model-predictive control(FMPC) which can realize operation optimizing function. The main objective is to achieve a smooth transition between the optimal mode switching and to ensure optimum goal can be realized. By implementation of proposed operating strategy in a four-component mixture Kaible column, the simulation results showed that this new method was feasible and concise.