Carbon steel and stainless-steel cathodic protection design data in Deepsea Water - Influence of the environment on the biofilm cathodic activity
2019 (English)In: NACE - International Corrosion Conference SeriesVolume 2019-March, 2019, Article number 13124Corrosion Conference and Expo 2019; Nashville; United States; 24 March 2019 through 28 March 2019, National Assoc. of Corrosion Engineers International , 2019Conference paper, Published paper (Refereed)
Abstract [en]
In natural seawater, many parameters might influence the cathodic protection current demand such as potential, temperature, dissolved oxygen content, biofilm and fouling activity, and calcareous deposit formation. The actual deepsea environment cannot be easily reproduced at laboratory scale. In this study, the influence of the depth on the cathodic protection criteria of carbon steel and stainless steel was investigated in intermediary (1020 m depth) and deep water (2020 m) at the same location. For this purpose, at set of corrosion and environmental sensors, as well as metallic coupons, were exposed during 11 months in Azores in the Atlantic Ocean. On stainless steel, a strong characteristic cathodic depolarization due to biofilm activity was observed in deep water and not in intermediary water. The biological-induced cathodic activity appears thus to be dependent on the environment, even in open seawater. In presence of an electroactive biofilm high and relatively stable current densities were measured. Under such conditions, an important structure depolarization appears, affecting thus the CP design and efficiency. For carbon steel, the cathodic protection data collected in-situ show that the initial and mean (after 11 months) current densities are higher than those recommended by the DNVGL RP B401 standard. Even if mean current densities are expected to continue to decrease slowly with further exposure time, so probably tending to the standard recommendations, the DNVGL RP B401 standard might not be conservative in terms of current densities criteria for these environments.
Place, publisher, year, edition, pages
National Assoc. of Corrosion Engineers International , 2019.
Keywords [en]
Biofilm, Carbon steel, Cathodic depolarization, Cathodic protection, Deep, Galvanic anode, Seawater, Stainless steel, Biochemical oxygen demand, Biofilms, Current density, Depolarization, Dissolved oxygen, Seawater corrosion, Calcareous deposit, Cathodic activity, Cathodic protection designs, Dissolved oxygen contents, Environmental sensor, Galvanic anodes
National Category
Natural Sciences
Identifiers
URN: urn:nbn:se:ri:diva-40466Scopus ID: 2-s2.0-85070103832OAI: oai:DiVA.org:ri-40466DiVA, id: diva2:1361267
Conference
NACE - International Corrosion Conference Series Volume 2019-March, 2019, Article number 13124 Corrosion Conference and Expo 2019; Nashville; United States; 24 March 2019 through 28 March 2019
Note
Funding text 1: The authors acknowledge the project participants for their material support and funding: Ulf Kivisäkk (AB Sandvik Materials Technology), Sandra Le Manchet (INDUSTEEL-ARCELOR-MITTAL), Elisabeth Johansson (OUTOKUMPU STAINLESS AB), Gwenaëlle Benoit and Morgan Gouriou (SAIPEM), Anne-Marie Grolleau (DCNS Research), Flavia Maciel (PETROBRAS). The authors acknowledge the European Union and the FIXO3 (Fixed point Open Ocean Observatory network) program which allows the access to a very pertinent exposure site according to the objective of this project, Jerome Blandin, Olivier Peden, Jean-Pierre Brulport, Pierre-Marie Sarradin from Ifremer for their logistical and technical crucial support for the array deployment and recovery campaign. Finally, thanks to Pascal Moullec and François Galéron, from the French Corrosion Institute, for their contributions to the instrumented array’s preparation. Many thanks to Olivier ROD from SWEREA Kimab for its kind and crucial collaboration in the FIXO3 call.
2019-10-152019-10-152023-05-26Bibliographically approved