再生水中水质因子对不锈钢管材的腐蚀影响及控制研究
发布时间：2018-11-11 15:52
【摘要】：本课题以热电厂循环冷却水系统为研究背景,以316L不锈钢(Stainless steel 316L,SS316L)为研究材质,以取自北京高碑店再生水厂的二级出水的再生水作为研究介质,以硫酸盐还原菌(Sulfate Reducing Bacteria,SRB)为研究菌种,采用水分析化学、生物化学、电化学和表面分析等方法,对北方4个代表性电厂(A、B、C、D)的再生水进行水质分析和评估;研究了浓缩3倍循环水中Cl-、氨氮、SO42-对SS316L电化学腐蚀影响;研究了 4种阻垢缓蚀剂之间的协同效应以及对SS316L的缓蚀效果;分别研究了杀菌剂和阻垢缓蚀剂对SS316L表面SRB生物膜化学组分及腐蚀行为的影响,从生物膜特性及膜下腐蚀的角度判断了药剂缓蚀性能的优劣。通过以上研究,本课题可以为热电厂防腐防垢的药剂选择提供一定的理论和数据支持。研究取得了如下成果:(1)水质分析评估表明,北方4个电厂的再生水中存在结垢问题,主要是CaCO3、BaSO4和Ca3(PO4)2等盐类的结垢;SO42-存在超标的问题,Cl-引起较大的腐蚀倾向;有机物含量较为丰富、含氮量超标,有利于微生物的滋生。(2)电化学研究表明,当浓缩3倍循环水中Cl-浓度超过380mg/L,Cl-对SS316L钝化膜的侵蚀作用明显加剧,表现为阳极溶解电流密度显著增加,最大达到2.11μA/cm2;当氨氮浓度超过15mg/L,氨氮对SS316L钝化膜的侵蚀作用明显加剧,最大阳极溶解电流密度达到1.01 μA/cm2;S042-与水中Cl-在SS316L表面存在竞争吸附,当SO42-浓度达到520mg/L时,此时[Cl-]/[SO42-]的值为0.54,浓缩3倍循环水对SS316L钝化膜的侵蚀被有效缓解,阳极溶解电流密度最大降幅达到59.0%,但随着浸泡时间的延长,腐蚀依旧有所加剧。(3)阻垢缓蚀剂复配研究发现,4种阻垢缓蚀剂的阻钙垢性能排序为:PESAPBTCAPASPHEDP,4种阻垢缓蚀剂对SS316L的缓蚀性能排序为:PBTCAPASPHEDPPESA;由于PESA与PBTCA能够增加羧酸基、磷酸基、羟基的数量,并且改变CaCO3晶体的结垢类型,二者同时具有最佳的阻垢和缓蚀协同效应,浓度比为1:3时,阻垢率达到最大,为97.8%;浓度比为1:1时,缓蚀率达到最大,为81.2%。(4)阻垢缓蚀剂和杀菌剂对SRB生物膜组分影响研究表明,PBTCA和PESA分别使得SS316L表面EPS含量增加了 1.4%和5.8%;由于不同的杀菌机理,异噻唑啉酮、NaClO和1227对EPS含量的削减率分别达到了 62.5%、70.3%和80.6%,其中,NaClO对蛋白质的削减能力最大,削减率为70.4%,1227对多糖的削减能力最大,削减率为84.0%,三种杀菌剂均能有效地抑制SRB及其生物膜在不锈钢表面的粘附。(5)阻垢缓蚀剂和杀菌剂均能改变SS316L表面生物膜形貌;X射线光电子能谱结果显示,添加NaClO后,SS316L表面-NH2的含量最低,从基团角度印证了 NaClO对蛋白质较强的削减能力,同时,检测到的FeCl2,表明NaClO对SS316L钝化膜产生了一定的侵蚀;1227能够大幅度改变SS316L表面膜中C:O比值,影响了以多糖为主的碳氧化合物的结构。(6)阻垢缓蚀剂和杀菌剂对SRB生物膜下SS316L腐蚀行为影响研究表明,PBTCA能够降低阳极溶解电流密度,而PESA可以微弱地促进微生物腐蚀;异噻唑啉酮、NaClO和1227均能有效抑制微生物腐蚀,但是,由于还原生成Cl-,NaClO急剧增大阳极溶解电流密度,降低击穿电位,侵蚀SS316L钝化膜;1227具有成膜性,使得击穿电位达到最大值1.19V,有助于钝化保护。交流阻抗图谱(EIS)表明,PBTCA和PESA能增加生物膜厚度;3种杀菌剂均能削减生物膜厚度,降低表面膜阻抗,NaClO使得SS316L表面膜阻抗降至最低,增大腐蚀风险,而1227条件下,膜阻抗值较高。本研究最终确定了最优复配阻垢缓蚀剂方案为PBTCA:PESA=1:1;最佳杀菌剂为1227,具有最优的杀菌和缓蚀性能。
[Abstract]:Taking the circulating cooling water system of the thermal power plant as the research background, taking 316L stainless steel (Sainless steel 316L, SS316L) as the research medium, as the research medium, the sulfate-reducing bacteria (SRB) was used as the research medium. The water quality of four representative power plants (A, B, C, D) in the north was analyzed and evaluated by water analytical chemistry, biochemistry, electrochemical and surface analysis. The effects of Cl-, ammonia nitrogen and SO42-on the electrochemical corrosion of SS316L were studied. The effect of corrosion inhibitor on the chemical composition and corrosion behavior of SRB biofilm on SS316L surface was studied. The effect of the corrosion inhibitor and the corrosion inhibitor on the chemical composition and corrosion behavior of SS316L surface was studied. Through the above research, this project can provide some theoretical and data support for the selection of anti-fouling agent for thermal power plant. The results are as follows: (1) The water quality analysis and evaluation show that the problem of scaling in the regeneration water of the four power plants in the north is mainly the scaling of the salts such as CaCO3, BaSO4 and Ca3 (PO4) 2; the problem that the SO42-is in excess of the standard, Cl-causes a large corrosion tendency; the organic content is rich, The nitrogen content exceeds the standard, which is beneficial to the breeding of microorganisms. (2) The electrochemical study shows that when the concentration of Cl-in the 3-fold circulating water exceeds 380mg/ L, the etching effect of the Cl-to the SS316L passivation film is obviously increased, and the dissolution current density of the anode is obviously increased, and the maximum reaches 2.11. mu. A/ cm2; when the concentration of the ammonia nitrogen exceeds 15mg/ L, The effect of ammonia nitrogen on the passivation film of SS316L is obviously increased, the maximum anodic dissolution current density is 1. 01.mu. A/ cm2, S042-and Cl-in the water are competitive adsorption on the surface of SS316L, when the SO42-concentration reaches 520mg/ L, the value of[Cl-]/[SO42-] is 0.54, The effect of 3-fold concentration of circulating water on the passivation film of SS316L is effectively relieved, the maximum reduction of the current density of the anode is 59. 0%, but with the extension of the soaking time, the corrosion is still increasing. (3) The anti-scale corrosion inhibitor compound study found that the corrosion resistance of four corrosion-resistant corrosion inhibitors was ordered to be: PESAPBTCAPASPHEDP, and the corrosion resistance of four kinds of scale inhibitor to SS316L was ordered as: PBTCAPASPHEEDPPESA; because of the addition of PESA and PBTCA to increase the number of acid-based, phosphoric and hydroxyl groups, and to change the scale type of CaCO3 crystals, When the concentration ratio is 1: 3, the corrosion resistance rate reaches the maximum, which is 97.8%, the concentration ratio is 1: 1, and the corrosion rate reaches the maximum of 81.2%. (4) The effect of the corrosion inhibitor and the bactericide on the composition of the SRB biofilm shows that the EPS content of the SS316L surface is increased by 1. 4% and 5. 8%, respectively, and the reduction rate of the EPS content is 62.5%, 70.3% and 80.6%, respectively, due to different sterilization mechanisms. Among them, the reduction ability of NaClO to the protein is the most, the reduction rate is 70.4%, the reduction capacity of 1227 to the polysaccharide is the most, the reduction rate is 84.0%, and the three fungicides can effectively inhibit the adhesion of the SRB and the biofilm to the surface of the stainless steel. The results of X-ray photoelectron spectroscopy show that after addition of NaClO, the content of SS316L surface-NH2 is the lowest, and the ability of NaClO to reduce the protein is confirmed from the group angle, meanwhile, FeCl2 is detected, The results show that NaClO has a certain erosion on the SS316L passivation film, and 1227 can greatly change the C: O ratio in the surface film of SS316L. The structure of the carbon-oxygen compound with the main polysaccharide is affected. (6) The study of the effect of the corrosion inhibitor and the bactericide on the corrosion behavior of SS316L in the SRB biofilm shows that the PBTCA can reduce the current density of the anode, and the PESA can effectively promote the corrosion of the microorganism. The reduction of Cl-, NaClO dramatically increases the anodic dissolution current density, decreases the breakdown potential and erodes the SS316L passivation film; 1227 has a film-forming property so that the breakdown potential reaches a maximum value of 1.19V, which contributes to the passivation protection. The exchange impedance map (EIS) shows that PBTCA and PESA can increase the thickness of the biofilm; 3 fungicides can reduce the film thickness, reduce the surface membrane impedance, and NaClO makes the surface film impedance of the SS316L surface drop to the lowest, increasing the corrosion risk, and under the 1227 condition, the membrane impedance value is high. The optimum anti-scaling inhibitor scheme is PBTCA: PESA = 1: 1, and the optimal bactericide is 1227, which has the best bactericidal and corrosion-resistant properties.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM621
本文编号：2325347
[Abstract]:Taking the circulating cooling water system of the thermal power plant as the research background, taking 316L stainless steel (Sainless steel 316L, SS316L) as the research medium, as the research medium, the sulfate-reducing bacteria (SRB) was used as the research medium. The water quality of four representative power plants (A, B, C, D) in the north was analyzed and evaluated by water analytical chemistry, biochemistry, electrochemical and surface analysis. The effects of Cl-, ammonia nitrogen and SO42-on the electrochemical corrosion of SS316L were studied. The effect of corrosion inhibitor on the chemical composition and corrosion behavior of SRB biofilm on SS316L surface was studied. The effect of the corrosion inhibitor and the corrosion inhibitor on the chemical composition and corrosion behavior of SS316L surface was studied. Through the above research, this project can provide some theoretical and data support for the selection of anti-fouling agent for thermal power plant. The results are as follows: (1) The water quality analysis and evaluation show that the problem of scaling in the regeneration water of the four power plants in the north is mainly the scaling of the salts such as CaCO3, BaSO4 and Ca3 (PO4) 2; the problem that the SO42-is in excess of the standard, Cl-causes a large corrosion tendency; the organic content is rich, The nitrogen content exceeds the standard, which is beneficial to the breeding of microorganisms. (2) The electrochemical study shows that when the concentration of Cl-in the 3-fold circulating water exceeds 380mg/ L, the etching effect of the Cl-to the SS316L passivation film is obviously increased, and the dissolution current density of the anode is obviously increased, and the maximum reaches 2.11. mu. A/ cm2; when the concentration of the ammonia nitrogen exceeds 15mg/ L, The effect of ammonia nitrogen on the passivation film of SS316L is obviously increased, the maximum anodic dissolution current density is 1. 01.mu. A/ cm2, S042-and Cl-in the water are competitive adsorption on the surface of SS316L, when the SO42-concentration reaches 520mg/ L, the value of[Cl-]/[SO42-] is 0.54, The effect of 3-fold concentration of circulating water on the passivation film of SS316L is effectively relieved, the maximum reduction of the current density of the anode is 59. 0%, but with the extension of the soaking time, the corrosion is still increasing. (3) The anti-scale corrosion inhibitor compound study found that the corrosion resistance of four corrosion-resistant corrosion inhibitors was ordered to be: PESAPBTCAPASPHEDP, and the corrosion resistance of four kinds of scale inhibitor to SS316L was ordered as: PBTCAPASPHEEDPPESA; because of the addition of PESA and PBTCA to increase the number of acid-based, phosphoric and hydroxyl groups, and to change the scale type of CaCO3 crystals, When the concentration ratio is 1: 3, the corrosion resistance rate reaches the maximum, which is 97.8%, the concentration ratio is 1: 1, and the corrosion rate reaches the maximum of 81.2%. (4) The effect of the corrosion inhibitor and the bactericide on the composition of the SRB biofilm shows that the EPS content of the SS316L surface is increased by 1. 4% and 5. 8%, respectively, and the reduction rate of the EPS content is 62.5%, 70.3% and 80.6%, respectively, due to different sterilization mechanisms. Among them, the reduction ability of NaClO to the protein is the most, the reduction rate is 70.4%, the reduction capacity of 1227 to the polysaccharide is the most, the reduction rate is 84.0%, and the three fungicides can effectively inhibit the adhesion of the SRB and the biofilm to the surface of the stainless steel. The results of X-ray photoelectron spectroscopy show that after addition of NaClO, the content of SS316L surface-NH2 is the lowest, and the ability of NaClO to reduce the protein is confirmed from the group angle, meanwhile, FeCl2 is detected, The results show that NaClO has a certain erosion on the SS316L passivation film, and 1227 can greatly change the C: O ratio in the surface film of SS316L. The structure of the carbon-oxygen compound with the main polysaccharide is affected. (6) The study of the effect of the corrosion inhibitor and the bactericide on the corrosion behavior of SS316L in the SRB biofilm shows that the PBTCA can reduce the current density of the anode, and the PESA can effectively promote the corrosion of the microorganism. The reduction of Cl-, NaClO dramatically increases the anodic dissolution current density, decreases the breakdown potential and erodes the SS316L passivation film; 1227 has a film-forming property so that the breakdown potential reaches a maximum value of 1.19V, which contributes to the passivation protection. The exchange impedance map (EIS) shows that PBTCA and PESA can increase the thickness of the biofilm; 3 fungicides can reduce the film thickness, reduce the surface membrane impedance, and NaClO makes the surface film impedance of the SS316L surface drop to the lowest, increasing the corrosion risk, and under the 1227 condition, the membrane impedance value is high. The optimum anti-scaling inhibitor scheme is PBTCA: PESA = 1: 1, and the optimal bactericide is 1227, which has the best bactericidal and corrosion-resistant properties.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM621
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