基于吸收塔动态模型的PID控制模拟研究

Simulation Research of PID Control Based on Dynamic Model of Absorption Tower

吸收塔是化工行业中重要的单元操作设备,对其模拟涉及了物料衡算、传递过程、填料层高度等计算。由于在流动中存在较大的停留时间,静态模型不能满足动态及控制模拟的需求,在之前的研究中结合单元传质模型及平推流动模型,建立了吸收塔的动态模型,可以模拟出塔内浓度分布随时间的变化。本文基于此动态模型,对吸收塔的PID控制过程进行了数值模拟。以出口浓度为目标,以稳定时间为评价指标,研究了不同的PID参数对于控制过程的影响,并选取了较优的控制参数。此方法对于研究系统的动态特性及调整自动控制参数有一定的意义。

Absorption tower is important unit operation equipment in chemical industry, and its simulation involves the calculation of material balance, height of packing layer and transfer process. The static model cannot meet the requirements of dynamic simulation. In previous studies, the unit mass transfer model and plug flow model were combined to obtain the dynamic model for absorption tower, which can simulate the change of concentration distribution in the tower. Based on this dynamic model and PID automatic control algorithm, the control process of absorption tower was numerically simulated. Taking the outlet concentration as the target and the stable time as the evaluation index, the influence of different PID parameters on the control process was studied, and the better control parameters were selected. This method can be used for studying the dynamic characteristics of the system and adjusting the parameters of automatic control.