Mixed metal oxide on a titanium substrate (MMO/Ti) is widely used as anode material for the cathodic protection of storage tank bottoms due to its advantages such as low consumption rate, long service life and ideal current distribution. However, with the elapse of service time, the MMO/Ti CP systems have been found with such issues as low polarization level and uneven potential distribution, threatening the operation safety of storage tanks. In this study, numerical modeling and subscale experiment were chosen to clarify the main factors responsible for the aforementioned issues. The results indicated that the inadequacy of polarization and the lack of uniform potential distribution were related to a combination of multiple factors, including the anode-to-tank bottom distance, the impressed current level, and the number of current impressing points. On the basis of these systematic analyses, this paper, conclusively, proposes certain design principles and maintenance suggestions for the cathodic protection system of tank bottoms.

Subject
Depolarization, Materials, Anode potential, Modeling, Welding, Conductors, Impressed current anodes, Anodic current, Titanium, Impressed current, Tank bottoms, Polarization, Anodes
Keywords:
storage tank bottom, mixed metal oxide, cathodic protection, numerical modeling, subscale experiment, potential distribution, depolarization
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2019
Association for Materials Protection and Performance (AMPP)
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