水质COD在线监测装置研究

发布时间：2017-12-27 14:18

本文关键词：水质COD在线监测装置研究　出处：《江南大学》2016年硕士论文　论文类型：学位论文

【摘要】：随着工业进程的不断深入,水资源受到严重的污染,其中有机物污染是增长最快、影响最普遍的污染之一。化学需氧量(COD,Chemical Oxygen Demand)是反映有机还原物质对产生或存在的水体污染的综合水质指标,需要对水质化学需氧量进行实时在线监测。当前,国内外COD分析仪采用的主要方法是重铬酸钾氧化回流消解法、高锰酸钾法、紫外分光光度法、微波消解法以及电磁感应加热法等,它们存在步骤繁琐、仪器成本高、需加入化学试剂易造成二次污染等缺点。需要研究出一种结构简单、方便快捷、测量精度高、没有二次污染的水质COD在线监测装置。本文的主要研究成果如下:1、基于臭氧协同紫外的水质COD在线监测装置,利用求耗氧量的方法测定COD值,对结果进行验证发现与理论值存在较大偏差。深入研究反应条件发现,实验过程中进臭氧量及反应温度对臭氧的溶解及分解有较大影响,利用这两个变量建立初步的COD非线性补偿模型。经验证改进后的测量值与实际值更接近。2、针对臭氧协同紫外原理联合氧化消解有机物的消解条件对水样氧化消解的效率具有较大影响的问题,利用正交试验设计了实验方案,寻找在线监测装置测定水质COD的最优消解条件,得到了包括消解过程中最优的消解时间、消解温度、进臭氧量以及消解溶液的pH值。使水样快速、彻底地氧化消解,大大提高了检测精度。3、针对初步改进后测定值不稳定的问题,分析出是实验过程中温度、pH值及COD浓度对溶解氧量有影响,利用支持向量机结合温度、pH值及与COD成正相关的二氧化碳生成量建立溶解氧量的估计模型,将COD测定结果用国标法验证发现,该模型补偿效果较好。4、对水质COD在线自动监测装置进行了改进优化设计,通过优化装置的检测流程、PLC控制模块以及装置的上位机界面,完善了COD远程在线监控装置,提高了装置的测量精度,延长了装置的使用寿命。
[Abstract]:With the continuous deepening of the industrial process, water resources are seriously polluted, and organic pollution is one of the fastest growing and most common pollution. Chemical oxygen demand (COD, Chemical Oxygen Demand) is a comprehensive water quality index reflecting the pollution of organic reducing substances to produce or existing water. It needs real-time online monitoring of water chemical oxygen demand. At present, the main methods used at home and abroad COD analyzer is potassium dichromate oxidation reflux digestion method, the Potassium Permanganate method, UV spectrophotometry, microwave digestion method and electromagnetic induction heating method, which is tedious, high instrument cost, need to add chemical reagents to cause two pollution etc.. It is necessary to study a COD on-line monitoring device for water quality, which is simple in structure, convenient and fast, with high measurement accuracy and no two pollution. The main research results in this paper are as follows: 1. Ozone based synergistic ultraviolet water quality COD on-line monitoring device, using the method of oxygen consumption to determine the COD value, and verify the results, and found that there is a great deviation from the theoretical value. Through in-depth study of reaction conditions, it is found that the amount of oxygen and reaction temperature has great influence on the dissolution and decomposition of ozone. We use these two variables to establish a preliminary COD nonlinear compensation model. The improved measurement value is closer to the actual value. 2, the efficiency of ozone oxidation combined with UV synergistic principle of organic matter digestion conditions of water oxidation has a greater impact on the problem, the experimental design using orthogonal test to find the optimal digestion conditions on-line monitoring device of water quality determination of COD, the optimal process including digestion, digestion temperature, digestion time ozone and digestion solution pH. The water sample is oxidized quickly and thoroughly, and the detection precision is greatly improved. 3, according to preliminary improved determination of instability problems, analysis of the temperature and pH value during the experiment and the concentration of COD has influence on the concentration of dissolved oxygen, the estimation model of support vector machine with temperature, pH value and COD and production of carbon dioxide is positively related to the establishment of the dissolved oxygen, the COD determination results by GB method proved that this model has better compensation effect. 4, the quality of COD on-line automatic monitoring device was improved through optimization design, optimization of device detection process, PLC control module and PC interface device, improve the COD remote on-line monitoring device, to improve the accuracy of measurement device, prolong the service life of the device.
【学位授予单位】：江南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X853

【相似文献】