基于流程模拟的中药生产过程溶媒回收工艺动态控制方法研究

Study on dynamic control method of solvent recovery process in traditional Chinese medicine production based on process simulation

目的 研究通过流程模拟和过程控制技术优化中药溶媒回收工艺控制结构,建立中药生产过程溶媒回收工艺动态控制方法。方法 针对中药溶媒回收过程中乙醇和水2组分的精馏工艺,在流程模拟平台分别建立添加再沸器热负荷与进料流量比值(Q_(Reb)/F)控制结构的控制系统以及回流物流量与进料流量成固定比值(固定R/F)控制结构的控制系统。通过考察系统在受扰动条件下运行状态的变化过程,分析了这2种控制结构对于中药溶媒回收工艺运行稳定性的影响。结果 在进料流量以及进料组分的干扰下,Q/F控制结构优于固定R/F控制结构,其减少了系统回复正常工艺状态的过渡时间,更好地保证了塔顶乙醇的回收率。结论 通过对不同设备尺寸模拟系统控制效果的对比,发现所建立的Q_(Reb)/F控制结构具有较强的普适性。进一步说明了Q_(Reb)/F控制结构在中药蒸汽机械再压缩(mechanical vapor recompression,MVR)浓缩工艺控制过程中可以通过增强测控参数关联性,降低控制响应迟滞,减少成本损失和能量浪费,为中药生产自动化控制升级提供了借鉴。

Objective The control structure of the recovery process of traditional Chinese medicine(TCM) solvent was optimized by process simulation and process control technology, and the dynamic control method of TCM solvent recovery process was established. Methods Based on the distillation process of ethanol and water in the recovery process of TCM solvent, the control system with the ratio of heat load of reboiler to feed flow(Q_(Reb)/F) and the control system with the fixed ratio of reflux flow to feed flow(fixed R/F) were respectively established on the simulation platform to complete the process control. The effect of these two control structures on the operation stability of the recovery process of TCM solvent was analyzed by investigating the operating state change process of the system under disturbed conditions. Results The Q_(Reb)/F control structure was better than the fixed R/F control structure under the interference of feed flow and feed components, which reduced the transition time for the system to return to normal process state. The Q_(Reb)/F control structure can better maintain the stability of the ethanol recovery rate. Conclusion After comparing the control effects of simulation systems with different equipment sizes, it was found that the Q_(Reb)/F control structure had strong universality. In the paper, the Q_(Reb)/F control structure was further discussed in mechanical vapor recompression(MVR)concentration control process. The control structure had many advantages in the process, such as the stronger control parameter correlation, the shorter control response delay, the less cost and energy consumption. Therefore, it will provide a reference for the upgrading automation control of TCM production.