Technical Evaluation of Cathodic Protection of Subsea Structures

International Journal of Research and Scientific Innovation (IJRSI) | Volume IX, Issue IV, April 2022 | ISSN 2321–2705

Technical Evaluation of Cathodic Protection of Subsea Structures

Precious Chisom Jumbo-Egwurugwu¹, Franklin Okoro², Ibe Emmanuel³, Obo-Obaa Elera Njiran⁴

^1,3,4University of Port Harcourt, Nigeria

²CleanScript Group

Abstract: This paper carried out the performance evaluation of cathodic protection in comparison with other corrosion prevention techniques based on factors like conductivity, maintenance requirement, cost, electrical continuity, and surface area of structure treated. In the course of the work, the comparative analysis of these techniques was carried out using a multi criteria analysis tool ‘TOPSIS’. After going through all the stages in the TOPSIS assessment, the best corrosion prevention technology with respect to all the considered criteria, which comprised of: treatment time, effectiveness, energy consumption, durability, economics and maturity is reinforcing materials with a TOPSIS score of 0.7745. The second-best technology is cathodic protection with a TOPSIS score of 0.6729, followed by surface treatment and coating with a TOPSIS score of 0.5903. Inhibitors came fourth with a TOPSIS score of 0.5897 while the worst technology per the analysis in this study is electrochemical chloride removal with a TOPSIS score of 0.2355.

Keywords: Cathodic protection; Corrosion; Subsea structures; TOPSIS.

I. INTRODUCTION

The impact of corrosion is three directional, the three aspects being economic, safety, and environment (Dong et al., 2012). The impact of corrosion, and the prevention thereof, is felt economically, and affects the safety and environmental conservation of resources. Economically, it implies the loss of infrastructure by way of loss of materials used in tanks, process equipment, pipelines, platforms, bridges, and many other important structures (Bernhammer et al., 2016). The economic losses could be direct or indirect. The direct losses would include, for example, the cost of replacing the corroded structures, equipment, and the cost of painting, upkeep, and monitoring of cathodic protection as well as the associated labour cost. Another cost would be the use of expensive corrosion resistance materials (Chew et al., 2016). The indirect cost of corrosion is difficult to assess accurately as more complex aspects come into play. However, activities that can be counted as contributing to the indirect cost of corrosion might include the closing of plants and facilities for repair and maintenance needed because of corrosion damages and failures. These costs add up because shut down involves reduction in production, loss of product, costs for cleaning and repair of environmental damages, and wages paid for the duration of the nonproductive time (Jang et al., 2015). In a nutshell, it can be said that indirect losses are a chain of activities that will take place and have to be paid for even when production is not there to support those costs. The loss of structure materials to corrosion is not only an

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