The paper presents a new multivariable control concept for falling film evaporators (FFEs). Our concept solves the major challenges encountered in modern FFE control: large transport delays, additional control of the output mass flow, coupling of controlled variables, and disturbances due to time-varying input dry matter content. The challenges are addressed together, for the first time, by the following control design. Based on a dynamic nonlinear input–output model, we consider a linearizing output transformation to enable application of classical linear control methods composed of feedforward design, disturbance rejection, and a decoupling network. Due to these features, we are able to design robust PID and PI controllers that substantially compensate plant-model mismatches. Connecting our concept to a digital twin of the plant yields good performance, which encourages future application of the design in the real-world process.

本文提出了一种新的降膜蒸发器 (FFE) 多变量控制概念。我们的概念解决了现代 FFE 控制中遇到的主要挑战：大的传输延迟、对输出质量流量的额外控制、受控变量的耦合以及因输入干物质含量随时间变化而引起的干扰。以下控制设计首次同时解决了这些挑战。基于动态非线性输入-输出模型，我们考虑线性化输出变换，以实现由前馈设计、干扰抑制和解耦网络组成的经典线性控制方法的应用。由于这些特性，我们能够设计出稳健的 PID 和 PI 控制器，这些控制器可以显着补偿工厂模型的不匹配。