Experts Discussed the Most Efficient Ways of Corrosion Protection

Corrosion of the offshore facilities not only creates hazardous working conditions but also makes adverse effect on the country economy. Efficient anticorrosion measures were discussed by participants of the session II «Electrochemical Protection and Operating Issues» that took place as part of the International Scientific and Practical Conference «Topical Issues of Rustproofing».

«The issue of a vessel hull corrosion and biofouling have always been going along with each other for several millennia, says Andrey Burkov, Adviser of the General Director of PSS Corporation. Even before Common Era the ancient Romans and Greeks, when sheathing the wooden ship hulls with lead plates as a method of worms and shells control, noted that if the plates were affixed with copper nails, some time later such plates rusted and fell off at the junctions. If a nail head is covered with lead or gold plating, the corrosive processes are radically reduced. Therefore, the fact of corrosion of metal objects in sea water was established and a method of passive electrochemical protection was applied. Further on, due to the development of electrical engineering, other rustproofing methods were found, and this area was developed as electrochemical protection».

According to the data of the Research Institute of Structural Materials «Prometheus», for 25 years corrosion of the icebreaker plate in the north polar regions may reach 4.5 mm, while it is reduced to 0.15 mm in case the electrochemical protection system is used. However, 15% of rust processes occur due to exposure to microorganisms.

«Bacteria just eat metal. And what they excrete, when they are stuffed, makes still more impact on the hull», Andrey Burkov noted. 

The expert singled out five effective rustproofing methods in shipbuilding, which should be applied as a whole. This includes applying varnish and paint coatings, sacrificial protection using sacrificial anodes, active cathodic protection by applied current with potential regulation, protection of the propeller-rudder group, and protection from biofouling of the outboard water fittings.

Vyacheslav Pershukov, Deputy General Director for Development of Khimservice CJSC devoted his report to the development of inter-state standard «Anodes of Cathodic Protection Units in Sea Water and Salt Media». The document regulates rustproofing of pipelines for oil and gas supply, berthing and hydrotechnical port facilities, he clarified. It covers the requirements to technical characteristics of cathodes, raw stuff and materials for making thereof and a number of other parameters.

According to the expert, each material of the anodes with maximum stability has its own advantages and disadvantages. For example, magnetite is notable for low cost and rather high admissible current density, has no voltage limitations and can function under negative temperatures. Metal oxide covered materials have relatively low rate of dissolution, high admissible current density, average cost, but have temperature limitations.

«In this regard, it is necessary to be very careful about the application thereof, because 90% of the Russian seas have winter temperatures up to 3 degrees below zero. Protection must be provided all year round, and this factor will adversely affect their functioning and reduce the service life dozens of times», commented Vyacheslav Pershukov.

Materials coated with catalytical metals have not only all advantages of the previous type, but also immunity to low temperatures. However, high cost is their disadvantage, the expert summarized.

According to Nikolay Glazov, Chief Scientific Officer of the Technical Inspection Department of Transneft R&D LLC, climatic and seasonal factors impede an opportunity to maintain «as needed» control of the technical state of protective coatings and equipment of the vessel’s electrochemical protection system. Due to this, priority should be given to remote monitoring and computer-aided diagnostic technologies. 

The session participants have also familiarized themselves with the anticorrosion equipment for pipelines, offshore and berthing facilities manufactured by JSC Pipeline Systems and Technologies. Such equipment comprises insulating monolithic sleeves, corrosion monitoring subsystems, small-sized cathodic protection station, anode ground beds, specialized software, etc. The information on their basic characteristics was provided by Aleksandr Shnyrev, Manager of the Marketing and Sales Department of JSC Pipeline Systems and Technologies. 

 

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Experts Discussed the Most Efficient Ways of Corrosion Protection

Corrosion of the offshore facilities not only creates hazardous working conditions but also makes adverse effect on the country economy. Efficient anticorrosion measures were discussed by participants of the session II «Electrochemical Protection and Operating Issues» that took place as part of the International Scientific and Practical Conference «Topical Issues of Rustproofing».

«The issue of a vessel hull corrosion and biofouling have always been going along with each other for several millennia, says Andrey Burkov, Adviser of the General Director of PSS Corporation. Even before Common Era the ancient Romans and Greeks, when sheathing the wooden ship hulls with lead plates as a method of worms and shells control, noted that if the plates were affixed with copper nails, some time later such plates rusted and fell off at the junctions. If a nail head is covered with lead or gold plating, the corrosive processes are radically reduced. Therefore, the fact of corrosion of metal objects in sea water was established and a method of passive electrochemical protection was applied. Further on, due to the development of electrical engineering, other rustproofing methods were found, and this area was developed as electrochemical protection».

According to the data of the Research Institute of Structural Materials «Prometheus», for 25 years corrosion of the icebreaker plate in the north polar regions may reach 4.5 mm, while it is reduced to 0.15 mm in case the electrochemical protection system is used. However, 15% of rust processes occur due to exposure to microorganisms.

«Bacteria just eat metal. And what they excrete, when they are stuffed, makes still more impact on the hull», Andrey Burkov noted. 

The expert singled out five effective rustproofing methods in shipbuilding, which should be applied as a whole. This includes applying varnish and paint coatings, sacrificial protection using sacrificial anodes, active cathodic protection by applied current with potential regulation, protection of the propeller-rudder group, and protection from biofouling of the outboard water fittings.

Vyacheslav Pershukov, Deputy General Director for Development of Khimservice CJSC devoted his report to the development of inter-state standard «Anodes of Cathodic Protection Units in Sea Water and Salt Media». The document regulates rustproofing of pipelines for oil and gas supply, berthing and hydrotechnical port facilities, he clarified. It covers the requirements to technical characteristics of cathodes, raw stuff and materials for making thereof and a number of other parameters.

According to the expert, each material of the anodes with maximum stability has its own advantages and disadvantages. For example, magnetite is notable for low cost and rather high admissible current density, has no voltage limitations and can function under negative temperatures. Metal oxide covered materials have relatively low rate of dissolution, high admissible current density, average cost, but have temperature limitations.

«In this regard, it is necessary to be very careful about the application thereof, because 90% of the Russian seas have winter temperatures up to 3 degrees below zero. Protection must be provided all year round, and this factor will adversely affect their functioning and reduce the service life dozens of times», commented Vyacheslav Pershukov.

Materials coated with catalytical metals have not only all advantages of the previous type, but also immunity to low temperatures. However, high cost is their disadvantage, the expert summarized.

According to Nikolay Glazov, Chief Scientific Officer of the Technical Inspection Department of Transneft R&D LLC, climatic and seasonal factors impede an opportunity to maintain «as needed» control of the technical state of protective coatings and equipment of the vessel’s electrochemical protection system. Due to this, priority should be given to remote monitoring and computer-aided diagnostic technologies. 

The session participants have also familiarized themselves with the anticorrosion equipment for pipelines, offshore and berthing facilities manufactured by JSC Pipeline Systems and Technologies. Such equipment comprises insulating monolithic sleeves, corrosion monitoring subsystems, small-sized cathodic protection station, anode ground beds, specialized software, etc. The information on their basic characteristics was provided by Aleksandr Shnyrev, Manager of the Marketing and Sales Department of JSC Pipeline Systems and Technologies. 

 

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