The below data has been used to calculate CP with galvanic anodes:
4.1 Casings and gasline dimensional details;
Galvanic anodes (protectors) dimensional and electrochemical parameters;
4.2 Soil resistivity measurements data provided earlier by Inzhtechservice company for the existing DB gaslines with the assumption that projected soil resistivity measurements will be within the presented one. For crossings 3 and 2 measurements are taken at the point 1.
For the pipeline and crossing 1 measurement data taken from one end at point 8.1, from the other end at point 1.2 and valued at average soil resistivity.
Calculation of CP with galvanic anodes will identify the following parameters:
• Current intensity in the protector – pipe circuit;
• Quantity of protectors required per each casing
• Protector’s design life
ASSUMPTIONS
The assumptions used for calculation of CP with galvanic anodes are as follows:
• Current density required
for soil with 10 Ohm resistivity maximum 10 mA/m²
• Coating breakdown 20 %
• Available magnesium in pre-packed anode 14.5(31,8)kg
• Electrochemical equivalent of protector material 3,95 kg/А*year
(for magnesium anode)
• Zinc Anodes 12,7mm х 14,3mm standard Standard Size 0.893kg/m
1,05V; 353A-h/lb or 237,31 A-h/ kg
CP CALCULATION BASIS – DEFINES INPUT PARAMETERS
