先进控制条件下化工过程操作裕量与控制性能分析

Manipulation margin and control performance analysis of chemical process under advanced process control

引言化工过程的设计裕量可以定义为考虑过程不确定参数（包括工艺条件、设备条件、外来扰动）发生变化时为满足生产和操作要求需要在正常操作的标称设计值上增加的量。

During chemical process design, the margin of manipulated variables must be determined not only for the possible change of process and equipment condition but also for the dynamic control of process control system, but its size cannot be too large in consideration of equipment cost. Now advanced process control, represented by predictive control provides a new method to improve process control performance. It is necessary to analyze the relationship between manipulation margin and control performance under advanced process control and find out the process design scheme to improve process control performance significantly at a lower cost of manipulation margin. So the mathematical description of solving the manipulation margin of chemical process under advanced process control is established. In advanced process control the linear model predictive control is used based on linear state space model, which is obtained through linearization on the steady nominal operating point, and the possible disturbances are also involved, then the problem is solved through dynamic optimization. The air flow rate margin of FCC regenerator was calculated as an example. When prediction horizon of predictive control was changed, different control performances were obtained and those corresponding manipulation margins were calculated. So the relationship between control performance and manipulation margin was found out.