Zeta电位实时在线监测系统的研究及其在废水处理中的应用

发布时间：2018-02-03 01:37

本文关键词： 废水处理 Zeta电位 PLC 神经网络 WinCC　出处：《广西大学》2016年硕士论文　论文类型：学位论文

【摘要】：废水已成为破坏环境和危害人类健康的因素之一,而造纸废水尤为严重。目前,造纸中段废水一般采用絮凝法进行处理,絮凝剂大多选用PAC和PAM,而PAC和PAM的投加主要依靠人工经验,精度低,易导致不足或者过量,不足的话,废水处理不完全,增加了后续处理废水的负担；过量意味着废水再次被絮凝剂污染,而且增加了处理成本。论文分析絮凝剂的作用机理,选用造纸中段废水的Zeta电位作为指导絮凝剂投加的依据,研究其实时在线测定方法以及絮凝剂的最优投加控制,以期实现絮凝剂的自动优化投加。目前,Zeta电位的测量仪器,比较成熟的有SZP04和Nano-ZS90型粒度分析仪,但都为离线测定,无法用于絮凝剂的自动在线投加。论文依据经典的Helmholtz-Smoluchowski公式,采用流动电位法,研制出一套Zeta电位实时在线测定装置,该装置由粘度计、电导率仪、差压变送器、复合陶瓷膜管、PLC等组成。此外为提高测定精确度还研究了压力差对测量结果的影响,从而找出最佳操作条件,使Zeta电位的测定尽量精确。通过与马尔文粒度分析仪的对比试验,证明该在线装置反映了Zeta电位的变化趋势,可用于絮凝剂的自动投加。此外,论文用STEP7和WinCC开发了Zeta电位的在线测定系统,具有良好的人机界面,运行效果良好。基于该在线测定装置,实时测定不同剂量絮凝剂下的Zeta电位值,采用最小二乘法进行曲线拟合,得到絮凝效果最佳时的Zeta电位值,作为后续设计的神经网络PID控制器的目标。该控制器由BP网络和PID控制器组成,通过BP网络调整出PID的三个参数,从而控制絮凝剂的投加。
[Abstract]:Wastewater has become one of the factors that damage the environment and human health, and papermaking wastewater is especially serious. At present, the wastewater in the middle section of papermaking is generally treated by flocculation, and the flocculants are mostly PAC and PAM. The addition of PAC and PAM mainly depends on artificial experience, low precision, easy to lead to insufficient or excessive, if insufficient, wastewater treatment is not complete, increasing the burden of subsequent treatment wastewater; Excessive amount means that the wastewater is polluted by flocculant again, and the treatment cost is increased. The mechanism of flocculant is analyzed in this paper, and the Zeta potential of waste water in middle section of papermaking is chosen as the basis of guiding flocculant dosage. The real-time on-line determination method and the optimal dosing control of flocculant were studied in order to realize the automatic optimal dosing of flocculant. The more mature SZP04 and Nano-ZS90 particle size analyzer, but both are off-line measurement. It can not be used for the automatic on-line adding of flocculant. According to the classical Helmholtz-Smoluchowski formula, the flow potential method is adopted in this paper. A real time on-line measuring device for Zeta potential is developed. The device consists of a viscometer, a conductivity meter, a differential pressure transmitter and a composite ceramic film tube. In addition, in order to improve the accuracy of the measurement, the influence of pressure difference on the measurement results was studied, and the optimum operating conditions were found out. By comparing with Ma Erwen particle size analyzer, it is proved that the on-line device reflects the change trend of Zeta potential and can be used for automatic dosing of flocculant. In this paper, STEP7 and WinCC are used to develop an on-line measuring system for Zeta potential, which has a good man-machine interface and good running effect. The Zeta potential of different dosages of flocculant was measured in real time, and the curve fitting was carried out by the least square method. The Zeta potential value of the best flocculation effect was obtained. The controller is composed of BP neural network and PID controller. The three parameters of PID are adjusted by BP neural network to control the adding of flocculant.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X84

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