基于电化学阻抗谱阴极保护控制系统的设计与研究

发布时间：2018-06-26 23:50

本文选题：电化学阻抗谱 + 阴极保护　；参考：《北京交通大学》2015年硕士论文

【摘要】：随着近年来海洋资源的不断开发,以钢筋混凝土材料为主的海洋平台大幅度投入使用。但是,由于其所处海洋环境的复杂性,时时处处受到腐蚀的危害,从而造成钢筋锈蚀、平台破坏、经济损失甚至人员伤亡。因此如何有效的对海洋环境下遭到电化学腐蚀的钢筋材料进行腐蚀防护,成为了近年来的热点问题。目前腐蚀防护普遍采用的方法包括覆盖腐蚀防护层、选用耐腐蚀材料、阴极保护。根据国内外的研究现状,电化学领域的阴极保护技术是一项有效的防护技术。阴极保护技术中最佳电位值的确定往往采用经验值法或阴极极化曲线法,但是这两种方法的准确性不高。通过调研发现,电化学阻抗谱对于确定电化学系统的各项参数非常直观准确,并且在腐蚀防护层的研究中已经取得了良好的效果。为了解决阴极保护中存在的准确度不高的问题,本文对阴极保护技术进行改进,提出了一种将电化学阻抗谱测量技术应用于确定强制电流阴极保护中最佳保护电位的方法,并进行实验验证。本文主要工作内容如下： 1、对海洋环境下阴极保护技术的发展应用以及电化学阻抗谱的发展应用进行分析。详细描述电化学阻抗谱的理论基础,为等效电路的确定、电化学阻抗谱技术在阴极保护中的应用提供理论依据。并分析了海洋环境下钢筋腐蚀机理、强制电流阴极保护原理,为基于电化学阻抗谱的阴极保护方案设计提供依据。 2、对阴极保护技术进行改进,将电化学阻抗谱技术应用到阴极保护中,应用直流信号和交流信号同时对电极系统进行扰动并在频率域对电极体系的电化学阻抗谱进行分析,以达到确定强制电流阴极保护中最佳保护电位值的目标。在该最佳保护电位值的控制下,使得电极系统的腐蚀电阻值最大,腐蚀程度最小,保护效果最佳。 3、通过仿真验证改进方案下阴极保护技术的可行性与准确性。首先搭建三电极体系,并通过Zview软件拟合体系的阻抗谱,分析出电极系统的等效电路。其次结合开路状态电极系统电化学阻抗谱分析,确定等效电路中元件参数,最后,通过以上确定的等效电路与元件参数,在Matlab软件中对于腐蚀系统的电化学等效电路进行建模,并应用直流信号和交流信号同时对电极系统进行扰动,仿真出极化过程的电化学阻抗谱、奈奎斯特图、波特图,确定出强制电流阴极保护的最佳保护电位值。此外对比阴极极化曲线的分析结果以及经验值,验证了本文对阴极保护技术的改进方法的可行性与准确性。
[Abstract]:With the continuous development of marine resources in recent years, the offshore platform with reinforced concrete material as the main material has been put into use. However, due to the complexity of its marine environment, corrosion is always and everywhere, resulting in steel corrosion, platform damage, economic losses and even casualties. Therefore, how to effectively prevent the corrosion of steel bars which are corroded by electrochemistry in marine environment has become a hot issue in recent years. At present, the common methods of corrosion protection include covering corrosion protection layer, selecting corrosion resistant material and cathodic protection. The cathodic protection technology in electrochemical field is an effective protection technology according to the current research situation at home and abroad. The best potential value in cathodic protection technology is usually determined by experience value method or cathodic polarization curve method, but the accuracy of these two methods is not high. It is found that electrochemical impedance spectroscopy is very intuitive and accurate in determining the parameters of electrochemical system and has achieved good results in the study of corrosion protection layer. In order to solve the problem that the accuracy of cathodic protection is not high, the cathodic protection technology is improved in this paper, and a method of determining the best protection potential in forced current cathodic protection by electrochemical impedance spectroscopy is proposed. Experimental verification was carried out. The main work of this paper is as follows: 1. The development and application of cathodic protection technology and electrochemical impedance spectroscopy in marine environment are analyzed. The theoretical basis of electrochemical impedance spectroscopy is described in detail, which provides a theoretical basis for the determination of equivalent circuit and the application of electrochemical impedance spectroscopy in cathodic protection. The corrosion mechanism of reinforcement in marine environment and the principle of forced current cathodic protection are analyzed in order to provide the basis for the design of cathodic protection scheme based on electrochemical impedance spectroscopy. 2. The cathodic protection technology is improved. Electrochemical impedance spectroscopy (EIS) was applied to cathodic protection. DC and AC signals were used to disturb the electrode system and the electrochemical impedance spectrum of the electrode system was analyzed in the frequency domain. In order to achieve the goal of determining the best protection potential in forced current cathodic protection. Under the control of the optimum protection potential, the corrosion resistance of the electrode system is the largest, the corrosion degree is the least, and the protection effect is the best. 3. The feasibility and accuracy of the cathodic protection technology under the improved scheme are verified by simulation. First, the three-electrode system is built, and the equivalent circuit of the electrode system is analyzed by fitting the impedance spectrum of the system with ZVIEW software. Secondly, combining with the electrochemical impedance spectrum analysis of the open circuit state electrode system, the element parameters in the equivalent circuit are determined. Finally, the electrochemical equivalent circuit of the corrosion system is modeled in Matlab software through the above determined equivalent circuit and component parameters. At the same time, the DC signal and AC signal are used to disturb the electrode system, and the electrochemical impedance spectrum, Nyquist diagram and Porter diagram of polarization process are simulated, and the best protection potential of forced current cathodic protection is determined. In addition, the feasibility and accuracy of the improved method for cathodic protection are verified by comparing the analytical results and experience values of cathodic polarization curves.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE985;TP273

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