ABSTRACT

Corrosion protection in soil and marine environments involves protective coatings and cathodic protection devices (anodes and referfence electrodes). In order to select proper technical solutions for cathodic protection of steel structure facilities, long-term field testing of reference electrodes and anodes are carried out. The experimental set-up was constructed and commissioned on port facilities in Kozmino (marine conditions) and in Ural region (in soils). The testing includes multiple models of anodes and reference electrodes. The types of anodes under investigation are silicon-iron, magnetite, conductive polymer, and titanium-based anodes (with platinum (Pt) and mixed-metal oxide (MMO) coatings). The tested reference electrodes are copper-sulphate (Cu/CuSO4), silver-silver chloride (Ag/AGCl), zinc (Zn), and bi-metallic reference electrodes. The basic parameters of reference electrodes and anodes will be evaluated. The remote monitoring system is applied for control of currents and potentials. The duration of testing is more than 1.5 year. The paper presents experimental procedures and some observations made in course of the testing.

INTRODUCTION

Transneft1 is oil and oil-products transport company, operates more than 70 thousand km of crude oil and oil-product trunk pipelines, and more than 500 pump stations with above 1500 storage tanks. The major part of the facilities were constructed in 1970-1980s and earlier. Corrosion protection of metallic facilities in soils is provided by protective coatings and cathodic protection. Also, the 4 sea ports with harbour and jetty installations are being operated. More than 7000 cathodic protection rectifiers with impressed current anodic groundings provide necessary protective current, and more than 60000 reference electrodes are installed to control protection potential. Therefore, impressed current anodes and reference electrodes are crucial elements of cathodic protection system, and the proper quality control and selection of efficient production is of high priority. Besides, improper selection of this equipment leads to untimely and costly repairs.

Multiple manufacturers of various quality impressed current anodes and reference electrodes are available on the market. The laboratory testing allows studying of the article properties more thoroughly and precisely, but it never gives information on real-conditions behaviour. Thus, the comparative field testing was chosen as the way to solve the task.

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