The dynamic control of the heat exchanger network is important for developing energy-efficient and safe industrial processes. In such a system, the control is achieved through the bypass stream around the heat exchanger. This work aims to track the setpoint temperature of the mixed stream by manipulating the bypass fraction of the cold stream around the heat exchanger. The implemented control is in a non-linear model predictive control (NMPC) framework. The first-principles model of a shell and a tube heat exchanger is used. The orthogonal collocation technique is used to discretize the first-principles model into the system of algebraic equations. In this work, uncertainty is also considered in the inlet temperature of the hot stream. The uncertain optimal control problem is dealt with by using a scenario tree-based approximation along with the affine policy-based method. The results show that, under different scenarios of uncertainty, the controlled variable efficiently tracks the setpoint. In comparison, considering the same scenarios of uncertainty used, the deterministic optimization approach shows significant deviation in the controlled variable from the setpoint as time passes.

中文翻译：

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不确定条件下换热网络的旁路控制

热交换器网络的动态控制对于开发节能和安全的工业过程非常重要。在这样的系统中，控制是通过热交换器周围的旁路流来实现的。这项工作旨在通过操纵热交换器周围冷流的旁路分数来跟踪混合流的设定点温度。实施的控制是在非线性模型预测控制 (NMPC) 框架中进行的。使用壳管式换热器的第一性原理模型。正交配置技术用于将第一性原理模型离散化为代数方程组。在这项工作中，热流的入口温度也考虑了不确定性。通过使用基于场景树的近似和基于仿射策略的方法来处理不确定的最优控制问题。结果表明，在不同的不确定性情景下，控制变量有效地跟踪设定点。相比之下，考虑到所使用的相同不确定性场景，确定性优化方法显示随着时间的推移，受控变量与设定值存在显着偏差。