动态实时优化策略下的分层式预测控制及其在化工过程中的应用

Hierarchical model predictive control based on dynamical real-time optimization and its application in chemical process

针对化工过程中那些因存在批处理、含有物料回流环节而很难达到稳态的过程以及一些因扰动的存在而很难精确地操作在一个设定点处的非线性过程,采用常规的稳态优化会产生低效或失效优化解的问题,提出一种动态实时优化策略。即在多层控制结构中的RTO层采用动态优化而非常规的稳态优化,依照过程的优化操作信息在满足过程动态规律和物料、产品市场价格变化的条件下实现生产的经济利润最优,事例仿真结果表明该方法的可行性和有效性。

For some chemical processes that are difficult to reach a steady state due to the existence of batch process or material recycle,as well as some nonlinear processes that difficultly operate nearby their desired set-points or reference trajectory because of the presence of disturbance,the sub-optimal or invalid optimal solutions will be derived if the normal steady state optimization scheme is used.In this paper,a dynamic real-time optimization strategy used for solving the optimum of the significant variables in chemical processes dynamically is proposed.Such a scheme is implemented in a hierarchical control structure,namely,the real-time optimization,which locates the top level in such hierarchy,is in charge of solving the optimum of some critical variables based on the dynamic model of a process,such optimization scheme is a kind of dynamic optimization other than steady state one,meanwhile,such scheme considers both dynamics of a process and material,prices of product in recent market,so the optimal economic profit will be arrived.The feasibility and efficiency of the proposed method is illustrated by a case study.