自来水厂药剂投加的前馈-反馈复合控制

Feedforward-feedback Hybrid Control of Chemical Dosing in Waterworks

自来水厂药剂(矾、臭氧、氣)投加量直接关系到对应工艺(絮凝、臭氧氧化、氯化)单元的处理效果,以及水厂出水水质是否达标和优质。当进水水质和进水流量变化时,如何实时调整药剂投加量以保证对应工艺的处理效果是自来水厂制水工艺运行优化的难点。在进水流量比例控制的基础上,提出一种基于原水水质在线综合评价和内模控制(IMC)的前馈-反馈复合控制方法。原水水质在线综合评价用于实时评估原水水质状况,并将评价结果用于药剂投加的前馈控制中,使药剂投加量能根据原水水质变化进行实时调整。IMC则用于药剂投加的反馈控制。实际水厂应用表明,与单纯IMC反馈控制相比,所提出的基于原水水质在线综合评价和IMC的前馈-反馈复合控制能更好地适应原水水质变化,有效提高了制水工艺的运行效率和出水水质的稳定性。

The chemical(alum,ozone and chlorine)dosage is directly related to the treatment effect of corresponding process units(flocculation,ozonation and chlorination)and the treated water quality at the waterworks.When the influent quality and flow changes,timely adjustment of the chemical dosage to ensure treatment efficiency is a challenge in operational optimization of the water treatment.A feedforward-feedback hybrid control method consisting of on-line comprehensive evaluation of raw water quality and internal model control(IMC)was proposed,based on the proportional control of water flow.On-line comprehensive evaluation of raw water quality provided the evaluation of the real-time condition of raw water quality,and were applied in the feedforward control of chemical dosing.The chemical dosage was adjusted in real-time in accordance with the raw water quality variation.IMC was adopted for the feedback control of chemical dosing.Experimental results showed that,in comparison with IMC feedback control,the proposed feedforward-feedback hybrid control of chemical dosing was better adapted to the variation of raw water quality,which effectively improved the operation efficiency of water treatment and the stability of treated water quality.