BP Perenco - Surface Preparation Corrosion and Coating Removal on Floating Steel Tank Roof
- Customer: BP Perenco
- Service: Surface Preparation - Steel
- Industry: Petrochemical, Oil & Gas
As the Oil and Gas industry continues to thrive within the UK, there are numerous essential maintenance works that must be carried out in order to meet industry standards, and enable safe efficient work to be carried out by the fuel terminal storage and distribution facilities. The storage facility at Hamble-Le-Rice contains a large number of tanks storing various fuels and 5 floating roof tanks for storing the crude oil supplied from Perenco’s onshore oil facility at Wytch Farm, Dorset.
Floating roof tanks
The floating roof tanks are painted to provide protection to the steel. Over time this surface becomes weathered and the roof must be stripped of all existing paint remnants, and cleaned to provide a suitable surface for the reapplication of a new protective paint coating. On tank 1102 considerable corrosion had taken place. The client had therefore specified a full blast clean to remove old paint and rust, to water jetting blast clean standard Wa2½. Specialist painting contractor Hertel approached RGL to investigate the possibility of offering ultra high pressure water blasting as an alternative to abrasive blasting.
The work was undertaken using 2 separate methods, the first was using a hand held low recoil safety lance with a rotary nozzle to provide easy access to the surrounding pontoon deck of the roof. This method was also employed to work around the roof leg supports protruding from the roof. It provided a cleaned circle of approximately 80cm diameter around each leg.
The second method involved using an automated machine, “Limpet Crawler System”, which has been designed and manufactured inhouse at RGL. This machine provides improved productivity levels compared to hand lancing.
The Limpet is powered by a hydraulic power pack and connects to a vacuum system. Waste Water is collected and filtered before being safely discharged back into the environment. The system employed for this project was a new modified version of the existing Limpet providing better control, improved productivity and reliability.
RGL provided one trained jetting crew (3 qualified men) to undertake the work. Due to the height of the tank roof location, the work (approximately 40 metres above ground level) it was necessary to have one operator at the work face, one monitoring the performance of the jetting unit and a safety stand by to communicate between the other two team members.
Once set-up on site the weather was the biggest obstacle to the works. After the corrosion and coating had been removed the Hertel team were on hand to apply the new paint coating straight away. However this was not possible during rain due to the likelihood of flash rusting occurring to the bare surface, meaning progress was slow for the first few days of the project. Once the weather improved RGL were able to get to work. With all the hand lancing work completed the focus was on utilising the Limpet to make up for lost time, and thanks to several dry days in a row the work was able to be completed on time despite the slow start.
The limpet enabled large areas to be prepared for the new paint application each day, allowing Hertel’s painters to start on these areas as the Limpet continued to work on the remainder of the tank. The Limpet was able to cover an area of between 80 and 200 square metres per day. All water was pumped to a holding tank before filtration to remove the majority of suspended solids. Filtered waste water met the site criteria for discharge into the reed bed effluent plant.
The use of vacuum recovery and waste water filtration enabled work to progress uninterrupted and meant that no waste water or debris was left to be cleared up by hand. Jeremy Twigg of RGL said “after the delayed start we were happy to get underway, and lend our expertise of this type of work to Hertel. The Limpet system is one of our best developments and comes into its own on projects such as this”.
Hertel Industrial Services contact for the project Ross McNally was happy with the results & this innovative method. Work had to be completed while the storage tank was full, and the floating roof was up. In spite of the bad weather and tight time frame, a top quality finish was achieved.
“RGL’s use of innovative methods ensured the desired result was achieved quickly, safely and effectively” Ross McNally of Hertel Industrial Services
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