沿海钢制储罐多种环境因子影响下的腐蚀规律研究

发布时间：2018-01-12 14:27

本文关键词：沿海钢制储罐多种环境因子影响下的腐蚀规律研究　出处：《浙江海洋大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着世界石油工业的迅速发展和能源需求的不断发展,原油和成品油的储备受到广泛关注,对各类油库储备能力的要求也越来越高,因而储罐数量大幅度增加。我国自2003年建起的国家石油储备基地中的大部分处于沿海地区,腐蚀环境较内陆而言更加恶劣,储罐寿命减短,并且造成严重的经济损耗,甚至在安全运行方面留下巨大的隐患。储罐是油品储运系统中重要环节,是生产过程不可缺少的主要设备,探究沿海钢制储罐多种环境因子影响下的腐蚀规律,不仅可以为我国钢制储罐的设计、建造、选材提供理论保障,同时对提高我国储罐设计能力和建造水平来说也具有非常重要的现实意义。本论文主要采用电化学实验方法,在实验室条件下对钢质储罐中常用钢材16Mn钢和Q235钢两种材料,分别在油品、氯离子、硫离子、微生物等不同环境因子影响下的腐蚀行为进行了研究。实验结果表明,16Mn钢在汽油、柴油、重油等油品的腐蚀行为受阴极控制,其中在汽油中的腐蚀速度最大,柴油次之,重油最小,这主要是因为氧在不同油品中溶解度不同导致的;在Cl-溶液中,Q235钢随着Cl-浓度的升高,自腐蚀电流密度减小,腐蚀速率减慢,当Cl-浓度大于10g/L时,腐蚀速度随着Cl-含量的升高而加快。16Mn钢在Cl-溶液中的腐蚀速率随着浓度增大而呈现先增加后减小的趋势;在S2-溶液中,S2-浓度增加使Q235钢的腐蚀速率呈现先加快后减慢而后趋于平缓的趋势,且随着硫离子浓度增加,阳极曲线愈发趋于钝化,当硫离子浓度大于2.5%时,阳极出现明显钝化区。16Mn钢随着硫离子浓度增加,腐蚀速率不断加快,但当S2-含量超过2.5%时,自腐蚀电流虽然还是增大,但是变化并不明显,原因是16Mn钢表面形成了具有保护性质的腐蚀产物膜;Cl-浓度对Q235钢在SRB中腐蚀行为影响显著。当溶液中Cl-含量低于50g/L时,随着Cl-含量增加,Cl-与SRB协同作用,Q235钢腐蚀速度加快;而当Cl-含量高于50g/L时,盐浓度升高抑制了硫酸盐还原菌的生长,Q235腐蚀速率随Cl-浓度增加而降低;不同的石油烃降解细菌对16Mn钢的腐蚀行为影响不同。16Mn钢在ASW-3中的腐蚀速率最快,ASS-2次之,ASW-1最慢。在ASW-1培养基中,随着生物膜的生长和脱落,16Mn钢的腐蚀速率先减小后增加;16Mn钢在ASW-3培养基中腐蚀速率基本变化不大;16Mn在ASS-2培养基中,随着ASS-2在代谢过程中产生的碱堆积,到第7天时腐蚀速率明显增加,腐蚀速度加快。
[Abstract]:With the rapid development of the world petroleum industry and the continuous development of energy demand, the reserve of crude oil and refined oil has received extensive attention, and the requirements for the reserve capacity of various oil depots are becoming higher and higher. As a result, the number of storage tanks has increased significantly. Most of the national oil reserve bases established in China since 2003 are located in coastal areas, the corrosion environment is worse than inland, and the life of storage tanks is shortened. The storage tank is an important part of the oil storage and transportation system, and is an indispensable main equipment in the production process. Exploring the corrosion law of the coastal steel storage tank under the influence of many environmental factors can not only provide theoretical guarantee for the design, construction and material selection of the steel storage tank in our country. At the same time, it is also of great practical significance to improve the design ability and construction level of storage tanks in China. This paper mainly adopts electrochemical experimental methods. Two kinds of steel materials, 16mn steel and Q235 steel, used in steel storage tank under laboratory conditions, were used in oil products, chloride ions and sulfur ions, respectively. The experimental results show that the corrosion behavior of 16mn steel in gasoline, diesel, heavy oil and other oil products is controlled by cathodes. The corrosion rate in gasoline is the largest, diesel oil is the second, and heavy oil is the least, which is mainly due to the different solubility of oxygen in different oils. With the increase of Cl-concentration in Cl-solution, the self-corrosion current density decreases and the corrosion rate slows down, when the Cl-concentration is more than 10g / L, the corrosion rate of steel Q235 decreases with the increase of Cl-concentration. With the increase of Cl- content, the corrosion rate of 16mn steel in Cl-solution increases firstly and then decreases. The corrosion rate of Q235 steel increased with the increase of S2- concentration in the solution. The corrosion rate of Q235 steel increased first and then slowed down, and the anodic curve tended to passivation with the increase of sulfur ion concentration. When the concentration of sulfur ion is greater than 2.5, the corrosion rate of the steel increases with the increase of the concentration of sulfur ion, but when the content of S ~ (2-) exceeds 2.5, the corrosion rate of steel is accelerated. Although the self-corrosion current is still increasing, the change is not obvious because of the corrosion product film formed on the surface of 16mn steel. The effect of Cl-concentration on the corrosion behavior of Q235 steel in SRB is significant. When the Cl-content in solution is less than 50g / L, the synergistic effect of Cl- and SRB increases with the increase of Cl-content. The corrosion rate of Q235 steel was accelerated; When the Cl- content was higher than 50 g / L, the corrosion rate of K2Q235 decreased with the increase of Cl- concentration, and the increase of salt concentration inhibited the growth of sulfate-reducing bacteria. The corrosion behavior of 16mn steel was affected by different petroleum hydrocarbon degrading bacteria. The corrosion rate of 16mn steel in ASW-3 was the fastest and the second was ASS-2. ASW-1 was the slowest. In ASW-1 medium, with the growth of biofilm and the corrosion rate of exfoliated 16mn steel, it decreased firstly and then increased. The corrosion rate of 16mn steel changed little in ASW-3 medium. The corrosion rate of 16mn in ASS-2 medium increased obviously at the 7th day with the accumulation of alkali in the metabolic process of ASS-2.
【学位授予单位】：浙江海洋大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE988

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