基于锌电解过程机理模型的酸锌浓度控制策略

Zinc-ion concentration control based on mechanical model of zinc electrowinning process

锌电解过程是一个典型的大惯性系统,电解槽的酸锌浓度往往难以控制。提出了基于锌电解机理模型的酸锌浓度前馈-反馈控制方法,以克服电流密度、进液浓度工艺参数的扰动。首先在Scott等提出的锌电解机理模型基础上,估计了传质系数等关键参数,得到了锌电解能耗模型,再加入电解槽酸锌浓度的物料动态平衡模型,从而建立了较完整的锌电解过程仿真模型。针对电流密度变化、进料中锌浓度波动等扰动引起电解液酸锌浓度变化的情况,提出了电解液锌浓度的前馈-反馈控制策略,其中反馈通道采用PID控制,而前馈通道的增益直接由机理模型计算得到。最后以仿真模型为对象验证了该控制策略,仿真结果表明该方法简单有效。

Zinc electrowinning process is a typical large time-delay system, so zinc ion and acid concentration are difficult to control. To overcome the fluctuations of current density and zinc ion concentration in the feed, feedforwar＆feedback control strategy based on the mechanism model of zinc electrolytic is used. First, based on the model given by Scott, the key parameters such as the mass transfer coefficient are estimated and the energy consumption model is built. Then, a more complete zinc electrowinning process simulation model is established by adding the dynamic balance model of zinc ion concentration in the cell. For the situation such as the changes of current density and fluctuations of feed zinc ion concentration that affect the zinc ion concentration in the cell, feedforward-feedback control strategy is put forward, where the feedback loop uses PID, while the feedforward gain is calculated directly from the mechanistic models. Finally, the control strategy is verified using the simulation model, and the results show that this method is simple and effective.