Abstract

The relevance of this work is conditioned by the need for maintaining a given temperature at the outlet of a heat exchanger under the conditions of variable flow rate and composition of the feedstock. This work reviews the methods for improving the heat exchanger control. The parameters of the control object are selected and its features are determined. A dynamic model of a heater with a steam space (shell-and-tube evaporator) applied for heating the gasoline fraction at the outlet of the topping column of the oil stabilization unit is obtained. The part of the distillate and fractional composition of the gasoline fraction, which is a disturbing factor, are determined. The mathematical model of the shell-and-tube evaporator is presented as an object with lumped parameters in the form of heat balance in a differential form taking into account transport delay. The heat transfer coefficient is determined from the side of gasoline fraction for the bubble boiling mode and from the side of stripped oil for the turbulent mode. A single-loop automated control system (ACS) and an ACS with the participation of the obtained model are implemented within Simulink. In the first case, the object model is represented in the canonical form in the state space. The intermediate signals (from matrix feedback amplifiers) are used as the control actions. In the second case, a combined temperature control system is developed at the outlet of the heat exchanger. The output signal of the model is supplied as a current parameter to controller 2, which generates a control signal that compensates for the disturbance. The task of controller 2 is the output signal of controller 1, which adjusts the operation according to the output temperature of the object. A comparison of the control methods with the use of standard controllers and with the participation of the developed object model is given. It is shown that the indicators of the transition process are higher when applying the models in the control.

中文翻译：

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换热器控制方法的比较

摘要

这项工作的相关性取决于在可变的流量和原料组成的条件下，必须在热交换器的出口处保持给定温度。这项工作回顾了改进热交换器控制的方法。选择控制对象的参数并确定其特征。获得了具有蒸汽空间的加热器（壳管式蒸发器）的动态模型，该加热器用于加热油稳定单元顶塔出口处的汽油馏分。确定馏分的一部分和汽油馏分的馏分组成，这是一个干扰因素。壳管式蒸发器的数学模型以具有集总参数的对象的形式呈现，以热平衡的形式（考虑了运输延迟）以微分形式出现。对于气泡沸腾模式，传热系数是从汽油馏分的一侧确定的；对于湍流模式，传热系数是从汽提油的一侧确定的。Simulink内实现了单回路自动控制系统（ACS）和参与获得的模型的ACS。在第一种情况下，对象模型在状态空间中以规范形式表示。中间信号（来自矩阵反馈放大器）用作控制动作。在第二种情况下，在热交换器的出口处开发了组合温度控制系统。在图2中，其产生补偿干扰的控制信号。控制器的任务2是控制器的输出信号1，它根据该物体的输出温度调节操作。比较了使用标准控制器和开发对象模型的控制方法。结果表明，在控件中应用模型时，过渡过程的指标较高。