Reinforced concrete seawater intake structures are a critical component to enable continuous operation of power stations, desalination plants, petrochemical plants and other heavy industries located near to the coast. The primary objective of these structures is to supply a reliable quantity of clean seawater, which can be used as per plant or refinery requirements. For continuous operation, seawater intake structures require protective screens to prevent debris and marine life entering and damaging the pumps. These screens are often manufactured from 316L Stainless Steel (SS), (UNS S31603), however within the Middle East this grade of stainless steel alone is considered insufficient to provide long term corrosion resistance. To overcome this problem, Cathodic Protection (CP) systems are utilized to protect the submerged sections of these screens with the aim of extending the life of the stainless steel equipment.

This paper will focus on the various design parameters required for CP of SS screens with particular attention on design and operational current density values and suitable protection criteria. The detrimental effects of overprotection will also be discussed.

A suitable case study is used to highlight the available anode systems, methods of monitoring and how maintenance worries can be overcome by state of the art remote monitoring and control systems, capable of controlling large scale CP systems from a single location using a standard internet web browser.

Subject
Electric current, Steel structures, Anode systems, Reference electrodes, Seawater, Current densities, Anodic current, Equipment, Remote monitoring, Zinc, Stainless steel, Protection potential, Anodes
Keywords:
Cathodic Protection, Remote Monitoring, Anode System, Reference Electrodes, Protection Criteria. Stainless Steel, Current Density, Protection Potential, Overprotection
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2017
Association for Materials Protection and Performance (AMPP)
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