Internal Protection of Fuel Tanks

A proposal for a draft standard on the requirements for the internal cathodic protection of fuel tanks has been put forward by a working party entitled Internal cathodic protection of fuel tanks [18]. This contains the following information an electrolyte is produced by dissolving sodium bicarbonate in drinking water with a resistivity not greater than 2000 Q cm. The solution should completely cover the anodes in the tank. 

The suction pipe of the tank must be arranged so that the electrolyte cannot be sucked out. Also, the filling pipe must be designed so that in filling, the electrolyte 

Anodes are connected to the object to be proteeted or to the transformer-rectifier by insulated conductors that are resistant to mineral oil (e.g., Teflon-coated cable) with a cross-section of 2.5 mm of Cu. The transformer-rectifier must meet the demands according to Ref. 6 and have the capability for monitoring and controlling its operation. The life of the anodes is in every case designed to be at least 15 years. 

Cathodic protection installations must be tested when commissioned and at least annually. The potentials should be measured at several points on the bottom of the tank with special probes under the oil, and the height of the electrolyte solution should be checked. The off potential and the protection potential as in Section 2.4 are the means for checking the protection criterion according to Eq. (2-39). 

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