工业循环水中阻垢缓蚀剂测定方法研究

发布时间：2018-05-16 08:49

本文选题：循环水 + 阻垢缓蚀剂　；参考：《山东大学》2017年硕士论文

【摘要】：循环冷却水系统是工业耗水中节省用量水的重要途径。伴随冷却水的连续运行,水系统中具有结垢趋势的矿物质浓度不停增长。过量的成垢离子富集会在管道表面产成沉积水垢,影响传热效率、产生垢腐蚀。投加聚合物阻垢缓蚀剂可有效解决此种难题。水处理剂必须达到一定浓度才能起到最佳的阻垢缓蚀效果,因此要实时监测循环水中阻垢剂的含量确保最佳浓度范围,从而达到阻垢、经济、环保的目的。本课题采用浊度法和胶体滴定法两种不同原理的测定方法分析循环水中聚合物的浓度含量。研究了这两种方法的适用条件和优弊性,从而对于不同循环水体系采用相应的分析测定方法。本实验得出的主要结论如下:(1)在一定质量浓度范围内,采用浊度法和胶体滴定法对各种聚合物阻垢剂测定时,阻垢剂浓度与吸光度值、聚二甲基二烯丙基氯化铵(PD)消耗的体积值均具有较强的线性相关性。(2)浊度法最佳测定条件、影响因素及消除PAA最佳试验条件:PD浓度16 mg/L,pH为3.50～5.50,稳定时间30 min,在410 nm处测吸光度,PAA浓度与吸光度呈现杰出的线性相关性R2=0.9950。共存的盐类及铜缓蚀剂于正常使用浓度内对PAA的检测均无影响。PO43-和含膦阻垢剂会对PAA的测定产生影响,研究发现,用Ca(OH)2调溶液pH值大于12,通过滴加0.75 ml 200 g/L Al2(SO4)3试剂可基本消除影响,检测限为1.04 mg/L。TH-2000最佳测试条件:PD浓度28.8mg/L,PH为4.50-7.00,稳定时间45min于425 nm处测吸光度,TH-2000浓度与吸光度线性相关性R2=0.9990。如同对PAA测定,P043-和含膦阻垢剂对溶液的测定有干扰,其他共存物质均无影响,加入Al2(SO4)3可基本消除PO43-和含膦阻垢剂的影响,检测限为0.448 mg/L。PASP最佳试验条件:PD浓度35.2 mg/L,pH为8.50～10.50,稳定时间25 min后于420 nm处测吸光度,PASP浓度与吸光度的线性相关性R2=0.9955。与PAA和TH-2000测定一样,PO43-和含膦阻垢剂会产生影响,通过加入Al2(SO4)3可基本消除影响,其他共存物质影响可忽略,检测限为0.738 mg/L。(3)胶体滴定法最佳测定条件、影响因素及消除PAA最佳试验条件:PD浓度40mg/L,pH为8.00～11.00,滴定速度小于0.100 mL/s,PAA浓度与消耗的PD体积具有较强的线性相关性R2=0.9692。Ca2+、Mg2+除外,体系剩余的盐类离子及水处理剂对PAA的测定影响可以忽略。伴随EDTA二钠的加入(物质的量比EDTA二钠:Ca2+或Mg2+略大于1:1)即可削弱Ca2+、Mg2+对PAA测定的影响,检测限为10mg/L。TH-2000最佳试验条件:PD浓度40 mg/L,pH为9.00～11.00,滴定速度不大于0.050 mL/s,TH-2000浓度与消耗PD体积的线性相关性R2=0.9869。与PAA测定类似,Ca2+、Mg2+对测定有影响,按物质的量比(EDTA二钠:Ca2+或Mg2+)至少为1:1添加EDTA二钠,即可减弱Ca2+、Mg2+对测定的干扰,该方法的检测限为16 mg/L。PASP最佳试验条件:PD浓度40mg/L,pH为8.50～11.00,滴加速度控制0.025mL/s内,PASP浓度与消耗PD体积的线性相关性R2=0.9787。共存盐类离子和水质稳定剂在正常质量浓度范围内对测定影响可以忽略。同样Ca2+、Mg2+对PASP的测定产生一定影响,通过添加EDTA二钠,即可削弱Ca2+、Mg2+对实验测定产生的影响,该方法的检测限为10 mg/L。(4)分析比较两种方法发现,浊度法准确性好、精密度较高,检出限低,对于低浓度的阻垢剂仍能检测;胶体滴定法操作简单费用低,实用性强,但检出限略高,适用于较高浓度阻垢剂的测定。这两种方法的确立,有利于循环水中聚合物含量及时准确测定,促进在线监测系统的完善,为循环水系统阻垢剂的监测提供理论和实践经验。
[Abstract]:The circulating cooling water system is an important way to save water in the industrial water consumption. With the continuous operation of cooling water, the concentration of minerals in the water system keeps increasing. Excessive accumulation of scale ions will produce sedimentary scale on the surface of the pipe, affect the heat transfer efficiency and produce scale corrosion. The water treatment agent must reach a certain concentration in order to achieve the best effect of scale inhibition and corrosion. Therefore, it is necessary to monitor the scale of the scale inhibitor in the circulating water to ensure the optimum concentration range, so as to achieve the purpose of scale inhibition, economic and environmental protection. This subject uses two different principles of turbidity and colloidal titration. The concentration of polymer in circulating water. The applicable conditions and advantages and disadvantages of these two methods are studied, and the corresponding analytical methods are used for different circulating water systems. The main conclusions of this experiment are as follows: (1) the determination of various polymer scale inhibitors by turbidimetric and colloidal titration in a certain mass concentration range. The concentration and absorbance value of the scale inhibitor, the volume value of the consumption of poly two methyl diallyl ammonium chloride (PD) have strong linear correlation. (2) the optimal determination conditions of the turbidity method, the influencing factors and the best experimental conditions for the elimination of PAA: the concentration of PD is 16 mg/L, pH is 3.50 ~ 5.50, the stable time is 30 min, the absorbance is measured at 410 nm, PAA concentration and absorbance are presented. The salt and copper corrosion inhibitor coexisting with outstanding linear correlation R2=0.9950. have no effect on the detection of PAA in normal concentration,.PO43- and phosphine containing scale inhibitor will affect the determination of PAA. The study found that the pH value of Ca (OH) 2 solution is greater than 12, and the effect can be basically eliminated by adding 0.75 ml 200 g/L Al2 (SO4) 3 reagents, and the detection limit is 1.04 m. G/L.TH-2000 best test conditions: PD concentration 28.8mg/L, PH 4.50-7.00, stability time 45min at 425 nm measurement absorbance, TH-2000 concentration and absorbance linear correlation R2=0.9990. as PAA determination, P043- and phosphine scale inhibitor have interference to the determination of solution, other coexisting substances have no effect, adding Al2 (3) can basically eliminate and contain phosphine The influence of scale inhibitor is the optimum test condition of 0.448 mg/L.PASP: the concentration of PD is 35.2 mg/L, pH is 8.50 ~ 10.50, the stability time is 25 min at 420 nm, and the linear correlation between PASP concentration and absorbance R2=0.9955. is the same as PAA and TH-2000, and PO43- and phosphine containing scale agent will have an effect. In addition to the influence, the influence of other coexisting substances is negligible, the detection limit of 0.738 mg/L. (3) colloid titration is the best condition, the influencing factors and the best experimental conditions for eliminating PAA are: PD concentration 40mg/L, pH is 8 ~ 11, titration speed is less than 0.100 mL/s, PAA concentration and PD volume consumed are strong linear correlation R2=0.9692.Ca2+, Mg2+ except for the body. The influence of the remaining salt ions and water treatment agents on the determination of PAA can be ignored. With the addition of EDTA two sodium (the amount of substance than EDTA two sodium: Ca2+ or Mg2+ is slightly greater than 1:1), the effect of Ca2+ and Mg2+ on PAA determination is the best test condition for 10mg/L.TH-2000: PD consistency 40 mg/L, 9 ~ 11, titration speed less than 0.050 The linear correlation between the concentration of L/s, TH-2000 and the consumption of PD volume is similar to that of PAA. Ca2+ and Mg2+ have an effect on the determination. The determination of interference by the mass ratio (EDTA two sodium: Ca2+ or Mg2+) at least 1:1 EDTA two can be reduced. The detection limit of this method is 16. ~ 11, drop acceleration control 0.025mL/s, PASP concentration and linear correlation of PD volume consumption R2=0.9787. coexisting salt ions and water quality stabilizers in normal mass concentration range can be ignored. Similarly Ca2+, Mg2+ has a certain effect on the determination of PASP, by adding EDTA two sodium, can weaken Ca2+, Mg2+ to experimental determination The detection limit of the method is 10 mg/L. (4) analysis and comparison of two methods. It is found that the turbidimetric method has good accuracy, high precision, low detection limit, and can still be detected for low concentration scale inhibitor; the colloid titration is low cost and practical, but the detection limit is high, which is suitable for the determination of high concentration scale inhibitor. These two methods It is beneficial to the timely and accurate determination of polymer content in circulating water, promote the improvement of on-line monitoring system, and provide theoretical and practical experience for monitoring the scale inhibitor of circulating water system.

【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ085.4

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