2205双相不锈钢在常压塔典型环境中的腐蚀蚀行为研究
发布时间：2018-08-26 15:42
【摘要】：2205双相不锈钢(2205DSS)作为优异的耐蚀材料,在炼油系统中的应用越来越广泛,同时也暴露出了不少腐蚀问题,因此研究其在该环境中的腐蚀机理具有重要的意义。本论文主要采用腐蚀失重法、动电位极化曲线、循环极化曲线、电化学交流阻抗谱(EIS)、微区电化学扫描开尔文探针(SKP)、扫描电子显微镜形貌分析(SEM)、X射线能谱仪(EDS)和X射线光电子能谱法(XPS)等研究手段研究了 2205DSS在常压塔典型环境中的耐蚀性能与腐蚀机理。首先,依据惠州炼化实际生产介质情况,研究了 2205DSS在油相中的腐蚀规律和腐蚀机理,结果表明油相空白馏分中2205DSS的耐蚀性稳定性高,受馏分和温度影响不大,其中在常二段馏分中的腐蚀速率最大,脱后原油中腐蚀速率最低。同时,研究了油相中的无机S和C1对腐蚀的影响作用,结果表明S、C1对于腐蚀的有一定的加速作用。其次,以常减压塔塔顶水相腐蚀为背景,进一步研究了 2205DSS在HCl + Na2S水溶液中的腐蚀机理。结果表明在含Na2S的HC1溶液中,HS_,H2S和OH-的竞争吸附对2205DSS的钝化膜再生有阻碍作用,因此Na2S对2205DSS在HC1中的点蚀有促进作用(Na2S含量低于30mg/L时除外)。另外,HS_、H2S和Cl_的竞争吸附在不同浓度HC1溶液对腐蚀产生不同的影响:HC1浓度为3.60 g/L时,30 mg/L的Na2S对2205DSS的均匀腐蚀有抑制作用;而Na2S浓度大于100 mg/L时,钝化膜溶解加快,局部有明显的腐蚀坑出现。而HCl浓度为5.00g/L时,30mg/L的Na2S将极大地促进2205DSS的均匀腐蚀,腐蚀以析氢腐蚀为主。最后,研究了 2205DSS在高浓度NaCl溶液中的点蚀行为。研究结果表明其在35.00 g/L的NaCl溶液中的临界点蚀温度在40～60℃之间。降低NaCl的浓度,其保护电位升高,滞后环面积变小,说明其耐点蚀性能随着NaCl的浓度减小而升高。单纯改变pH值对2205DSS耐点蚀能影响不大。碱性的NaCl环境中,Na2S增加了均匀腐蚀速率,钝化膜的局部自催化腐蚀效应作用减小,发生点蚀的可能性降低。而在中性NaCl溶液中加入Na2S会导致钝化膜溶解速率加快,点蚀电位降低,维钝电流增加,耐点蚀性能降低。
[Abstract]:As an excellent corrosion resistant material, 2205 duplex stainless steel (2205DSS) is more and more widely used in oil refining system and has exposed many corrosion problems. Therefore, it is of great significance to study the corrosion mechanism of 2205 duplex stainless steel (2205DSS) in this environment. In this paper, corrosion weightlessness method, potentiodynamic polarization curve, cyclic polarization curve are used. Electrochemical Impedance Spectroscopy (EIS), Microarea Electrochemical scanning probe (SKP), scanning Electron Microprobe Morphology Analysis (SEM) X-ray Energy Spectrometer (EDS) and X-ray photoelectron Spectroscopy (XPS) have been used to study 2205DSS in typical environment of atmospheric tower. Its corrosion resistance and corrosion mechanism. Firstly, according to the actual production medium of Huizhou refinery, the corrosion law and corrosion mechanism of 2205DSS in oil phase are studied. The results show that the corrosion resistance of 2205DSS in the blank fraction of oil phase is high, but not affected by the fraction and temperature. The corrosion rate is the highest in the ordinary fraction and the lowest in the crude oil after desorption. At the same time, the effect of inorganic S and C1 in oil phase on corrosion was studied. Secondly, the corrosion mechanism of 2205DSS in HCl Na2S aqueous solution was further studied under the background of water phase corrosion at the top of the tower. The results show that the competitive adsorption of H2S and OH- in HC1 solution containing Na2S can hinder the regeneration of 2205DSS passivation film, so Na2S can promote the pitting corrosion of 2205DSS in HC1 (except when Na2S content is lower than 30mg/L). In addition, the competitive adsorption of HSH _ 2S and Cl_ in different concentrations of HC1 solution had different effects on corrosion. Na2S of 30 mg/L at the concentration of 3.60 g / L of HC1 could inhibit the uniform corrosion of 2205DSS, while when the concentration of Na2S was more than 100 mg/L, the dissolution of passivation film was accelerated. There are obvious corrosion pits in the area. When the concentration of HCl is 5.00g/L, 30 mg / L Na2S will greatly promote the homogeneous corrosion of 2205DSS, and the corrosion is mainly hydrogen evolution corrosion. Finally, the pitting behavior of 2205DSS in high concentration NaCl solution was studied. The results show that the critical pitting temperature in 35.00 g / L NaCl solution is between 40 鈩，
本文编号：2205368
[Abstract]:As an excellent corrosion resistant material, 2205 duplex stainless steel (2205DSS) is more and more widely used in oil refining system and has exposed many corrosion problems. Therefore, it is of great significance to study the corrosion mechanism of 2205 duplex stainless steel (2205DSS) in this environment. In this paper, corrosion weightlessness method, potentiodynamic polarization curve, cyclic polarization curve are used. Electrochemical Impedance Spectroscopy (EIS), Microarea Electrochemical scanning probe (SKP), scanning Electron Microprobe Morphology Analysis (SEM) X-ray Energy Spectrometer (EDS) and X-ray photoelectron Spectroscopy (XPS) have been used to study 2205DSS in typical environment of atmospheric tower. Its corrosion resistance and corrosion mechanism. Firstly, according to the actual production medium of Huizhou refinery, the corrosion law and corrosion mechanism of 2205DSS in oil phase are studied. The results show that the corrosion resistance of 2205DSS in the blank fraction of oil phase is high, but not affected by the fraction and temperature. The corrosion rate is the highest in the ordinary fraction and the lowest in the crude oil after desorption. At the same time, the effect of inorganic S and C1 in oil phase on corrosion was studied. Secondly, the corrosion mechanism of 2205DSS in HCl Na2S aqueous solution was further studied under the background of water phase corrosion at the top of the tower. The results show that the competitive adsorption of H2S and OH- in HC1 solution containing Na2S can hinder the regeneration of 2205DSS passivation film, so Na2S can promote the pitting corrosion of 2205DSS in HC1 (except when Na2S content is lower than 30mg/L). In addition, the competitive adsorption of HSH _ 2S and Cl_ in different concentrations of HC1 solution had different effects on corrosion. Na2S of 30 mg/L at the concentration of 3.60 g / L of HC1 could inhibit the uniform corrosion of 2205DSS, while when the concentration of Na2S was more than 100 mg/L, the dissolution of passivation film was accelerated. There are obvious corrosion pits in the area. When the concentration of HCl is 5.00g/L, 30 mg / L Na2S will greatly promote the homogeneous corrosion of 2205DSS, and the corrosion is mainly hydrogen evolution corrosion. Finally, the pitting behavior of 2205DSS in high concentration NaCl solution was studied. The results show that the critical pitting temperature in 35.00 g / L NaCl solution is between 40 鈩，
本文编号：2205368
本文链接：https://www.wllwen.com/kejilunwen/shiyounenyuanlunwen/2205368.html
