COMMON PROBLEMS STORAGE TANKS FACE:
Above ground industrial storage tanks and their contents are extremely valuable assets that need to be protected. There are a wide range of problems that can cause damage and deterioration to both the storage tanks and surrounding environments if left untreated. Prolonged exposure to adverse weather conditions and working environments will eventually begin to take its toll on such assets.
In our previous blog, Cold Applied Corrosion Solutions for Storage Tanks, we highlighted these typical problems in more detail. Ultimately, these types of issues can lead to structural damage such as wall/roof defects and leakages.
Damage and deterioration not only happens to the tanks themselves, but also the surrounding areas. Secondary containment or bunding is designed to hold the contents of a tank in the event of catastrophic failure. A major failure of this nature, however, is both costly and potentially dangerous. Loss of the contents of the tank, disposal costs, clean-up costs and potential ultimate scrapping of the tank itself can amount to very significant losses and safety issues.
CASE STUDY - A DETERIORATING PROBLEM:
A storage tank farm based in Italy was used as a collection site for exhausted oil from machinery. After an intervention from the environmental monitoring public authority, pollution problems were detected within the site. Due to the gradual deterioration of the storage tanks from environmental damage and internal corrosion, the tanks and surrounding containment areas didn’t meet environmental standards. Therefore, the site required a complete refurbishment.
Belzona’s Italian Distributor, BS SRL, were able to offer a complete turnkey solution to restore the deteriorating tank farm. Through a constant local presence, BS SRL were able to provide a reliable, long-term and high-quality technical proposal.
RESTORING THE TANKS WITH BELZONA:
The internals of the tank needed a suitable coating that could provide protection against the oils. Due to a mixture of water and hydrocarbons, the bottom of the tank started to corrode where the water sits. This is because the density of the water is greater than the hydrocarbons and as the steel is unprotected, the tank corroded at the bottom.
Belzona 5811 (Immersion Grade) was chosen due to its ability to provide protection for surfaces operating under immersion, whilst also providing chemical resistance to the oil.
The storage tank was drained, and power washed to get rid of any loose contaminates and debris. Once dry, the tank was grit blasted to SA 2.5 before 2 coats of Belzona 5811 were applied to the floor and roughly 1 meter up the internal walls.
For the external surfaces of the storage tank, the surface was once again grit blasted to SA 2.5 before firstly applying 2 coats of Belzona 6111 (Liquid Anode). This zinc-rich epoxy system acts as a long-term steel protection system for surfaces subject to environmental corrosion. Belzona 6111 was then followed by 2 coats of Belzona 5111 (Ceramic Cladding) for its good UV resistance. The system also provides an aesthetically pleasing finish whilst also providing long-term protection to the storage tank.
The base of the storage tanks needed to be repaired and protected due to wear. Over time, moisture accumulated at the chime angle of the tank, leading to corrosion. Tank base corrosion can also be caused by the expansion and contraction of the tank or failure of mastic type sealants.
Conventional sealing methods, such as mastic tapes, are subject to shrinkage and UV attack. These methods also do not allow moisture to escape. A solution needs to be put in place to allow trapped moisture to permeate out, allow flexibility for expansion loading, and offer a long-term, durable solution.
The tank base firstly had to be rebuilt to the original surface due to a loss of material over time. If left without treatment, the structural integrity of the tank base would have been at risk. Belzona 4111 (Magma-Quartz) was chosen to resurface the tank base. Unlike conventional methods, this repair composite is easy to mix and apply without the need for specialist tools. Downtime is also reduced due to the fast-curing properties of the system.
For the sealing of the tank base, Belzona 3111 (Flexible Membrane) was the ideal solution due to its microporous properties, flexibility and proven track record in providing long-term protection for tank bases.
As well as the storage tanks, the surrounding containment areas did not meet environmental standards due to the damage suffered. These areas are subjected to environmental damage, as well as mechanical or structural damage.
The concrete floor surrounding the tanks had also gradually deteriorated over time. Some areas suffered a large amount of material loss, creating an uneven surface.
A solution was needed that would reduce downtime as well as offering exceptional compressive strength, good impact resistance and excellent adhesion to the existing concrete. Belzona 4111 (Magma-Quartz) was chosen to resurface the concrete floor.
The total area that needed to be refurbished was 1100m². Expansion joints were installed to allow the floor to expand and contract without any cracking. Belzona 4521 (Magma-Flex Fluid) offered a cost-effective and high performance alternative over conventional mastics and sealants. The material demonstrates long-term flexibility, accommodating for horizontal and shear movement up to 25%.
THE COMPLETED RESULT:
The storage tank farm was provided with a long-term, full turnkey solution that met environmental standards. The systems put in place ensure that the service life of the tanks are extensively prolonged, with no need for short-term maintenance.
Since the rejuvenation, the storage tanks have been in service and performing with no problems.