乳酸提纯新工艺动态建模仿真和控制系统设计

基于非平衡级和拟均相假设,建立了乳酸提纯反应精馏新工艺实验装置的动态机理模型.通过改进的数值计算方法提高了模型的求解效率,设计并实现了包含物性估算系统的模型仿真平台,以促进新工艺的工业化应用.利用仿真平台对新工艺装置进行了动态特性分析,在此基础上设计了两种单端质量控制方案:直接物料平衡和间接物料平衡方案.在不同类型和幅度的过程扰动下,分析比较了两种控制方案的调节性能.结果表明直接物料平衡方案控制品质优于间接物料平衡方案,可在不同扰动情况下满足过程的产品质量和转化率的联合控制要求.非平衡级动态机理模型能够反映反应精馏过程的动态特性,分析发现反应精馏过程有着独特的过程特性,基于机理模型的仿真平台是分析反应精馏特性的有效工具.

Dynamic Characteristics Analysis and Control System Design of the Reactive Distillation Process for Refining Lactic Acid

Reactive distillation is a developing new chemical engineering operation technic. In order to accelerate its industrial application, the study on a reactive distillation pilot equipment for lactic acid refinement was conducted. A non-equilibrium dynamic model was developed, and a simulation platform including property estimation system was constructed. By using effective numerical algorithm, the applicability of the model was improved. Two single-end purity control strategies, direct and indirect mass balance control, were designed, and their regulation performances were compared by evaluating the product quality variation on the sensitivity stage under different magnitude of feed composition disturbances. The sensitivity stage mentioned above was located by the dynamic characteristics analysis. The results show that the direct mass balance control scheme outstrips the indirect one and can well satisfy the control requirement for both product quality and conversion rate. The results also show that the dynamic model developed can successfully reveal the dynamic characteristics of the reactive distillation which are quite different from that of the non-reactive distillation, and the simulation platform constructed is effective for the reactive distillation process study and control strategy design.