油气管道阴极保护中IR降的测量及修正

发布时间：2018-03-19 13:09

本文选题：阴极保护　切入点：试片断电法　出处：《西安石油大学》2015年硕士论文　论文类型：学位论文

【摘要】：目前外加电流阴极保护己经广泛应用于油气管道的防腐保护中,阴极保护电位作为管道阴极保护状态的重要评价指标,在实际测量过程中由于IR降的存在,不能得到真实电位。试片断电法操作简单方便,可以有效的减少IR降对保护电位的影响,因此,本文研宄油气管道阴极保护中IR降的测量及修正具有较高的理论价值和应用前景。本文在实验室模拟阴极保护系统,选用20号钢作为试片。用扫描电子显微镜对不同保护电位下的试片进行了腐蚀形貌的观察和分析。在不同试片裸露面积、不同参比电极距离、不同土壤电阻率条件下,采用试片断电法对试片的断电电位和去极化电位进行了测量,并进行了对比分析。采用试片失重法对试片在不同保护电位下的保护效果进行了分析判断。对一定条件下试片的断电电位的计算总结出了经验公式。结果表明:合适的阴极保护电位可以有效的抑制金属的离子化,对试片进行充分的保护;随着试片的裸露面积和参比电极距离的增加,IR降越大,试片断电电位正移;随着土壤电阻率变大,IR降减小,试片断电电位负移;试片断电法的IR降在几十到几百毫伏之间,随着通电电位的上升,IR降增大;IR降修正方程是行之有效的。综上所述,懫用试片断电法可以有效的减少油气管道阴极保护过程中因IR降造成的保护电位测量误差,但要保证测量的准确性,试片的的裸露面积必须与管道保护层的破损情况相E配。
[Abstract]:At present, the applied current cathodic protection has been widely used in the anticorrosion protection of oil and gas pipeline. The cathodic protection potential, as an important evaluation index of the cathodic protection state of the pipeline, is due to the existence of IR drop in the actual measurement process. No real potential can be obtained. The test strip power cut method is simple and convenient, and can effectively reduce the effect of IR drop on the protective potential. In this paper, the measurement and correction of IR drop in cathodic protection of oil and gas pipeline has high theoretical value and application prospect. In this paper, the cathodic protection system is simulated in laboratory. The corrosion morphology of steel 20 was observed and analyzed by scanning electron microscope (SEM). Under different exposed area, different reference electrode distance and different soil resistivity, the corrosion morphology of steel 20 was observed and analyzed by scanning electron microscope (SEM). The breakage potential and depolarization potential of the test piece were measured by the method of test strip power failure. The method of weightlessness is used to analyze and judge the protective effect of the test piece under different protective potentials. The empirical formula for the calculation of the electric potential of the test piece under certain conditions is summarized. The results show that:. The proper cathodic protection potential can effectively inhibit the ionization of metals. With the increase of the exposed area and the reference electrode distance, the positive shift of the breakage potential was observed, and the negative shift of the breakage potential decreased with the increase of the soil resistivity, and decreased with the increase of the surface area of the specimen and the distance of the reference electrode. The IR drop of the test piece power cut method is between tens and hundreds of millivolts. The correction equation of IR drop increases with the increase of the electric potential. In order to ensure the accuracy of the measurement, the exposed area of the test piece must be matched with the damage of the protective layer of the pipeline, in order to ensure the accuracy of the measurement, it can effectively reduce the error of the protection potential measurement caused by IR drop in the process of cathodic protection of oil and gas pipeline by using the method of test strip power failure.
【学位授予单位】：西安石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE988.2

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