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The cathodic protection project of oil tank group in Dongjikou Port of Qingdao is the core supporting project of crude oil commercial reserve project . Covering phases I, II and III, there are 52 floating roof storage tanks of 100,000 cubic meters with a total storage capacity of 5.2 million cubic meters. The combined protection technology of flexible anode + potentiostatic meter + sacrificial anode is adopted. Ensure that the tank bottom and other key parts in the Marine high salt and high humidity environment 30 years or more anti-corrosion life .
cathodic protection system configuration
flexible anode technology : Laying conductive plastic flexible anode on the bottom plate of the storage tank, and combining with potentiostat to dynamically adjust the protection current, the anode coverage rate of a single tank can reach 100%, and the protection potential is stable in the range of -0.85V to -1.20V (CSE), which can effectively inhibit electrochemical corrosion .
sacrificial anode auxiliary protection : The zinc-aluminum alloy sacrificial anodes are embedded at the perimeter of the tank area. The ground resistance is reduced by filling with coke powder, and the protection redundancy in local high-risk areas is improved.
Equipment and material selection
explosion-proof reference electrode and intelligent control cabinet were used to monitor changes in tank bottom potential in real time, and dynamic adjustment of protection current density 13 was realized through remote central control platform.
The outer anti-corrosion layer of the tank is coated with fused epoxy powder (FBE) enhanced grade , and the inner wall is coated with oil-resistant polymer composite coating to prevent the penetration of corrosive media .
large-scale construction and acceptance
The project is divided into three phases. The first and second phases will be put into operation in 2021 and 2022 respectively. The third phase will be completed in August 2023. With an additional storage capacity of 1.2 million cubic meters, the largest single oil product reservoir area along the coast will be formed with a total storage capacity of 11.06 million cubic meters .
The technology of in-situ potential detection + coating integrity scanning is adopted for completion acceptance to ensure that the coverage rate and effectiveness of the cathodic protection system are over 98% .
Ecology and security in coordination
During the construction period, vegetation damage is reduced by green engineering method , and the risk of working at altitude is reduced by flip loading technology, so as to achieve the goal of "zero safety accidents" 45.
The project is interconnected with the crude oil terminal and long-haul pipeline in Dongjiakou Port area, improving the efficiency of oil storage and transportation, with an annual turnover of more than 8.5 million tons, and ensuring the raw material supply of the hinterland's petrochemical industry .
This project is the first full-life cathodic protection demonstration project of very large scale oil tank group in China, overcoming the difficult problem of tank floor corrosion control in Marine environment. Its model of " dynamic monitoring + multistage protection " provides a technical benchmark for similar port energy reserve projects .
