THE PROBLEM
The two stainless steel tanks required a suitable chemical resistant tank lining in order to protect their internals from the high concentration chlorine that was to be stored within them.
Stainless Steel Chlorine Tanks Lining, Norfolk
THE SOLUTION
Following the advice from one of our trusted suppliers Chemco International we proposed the application of their glass flake reinforced vinyl ester tank lining – Chem-Tect RB300.
Initially the tank internals were high pressure washed to ensure that they were both clean and free from chloride contaminants. Oils and greases if presents would prevent proper adhesion of the new tank lining and chlorides if left in place can lead to a phenomenon called Osmotic blistering in the new tank lining.
Following washing and pumping out the tank internals were checked for oils and grease contamination using a Blacklight
Elcometer 134S test kits were used to check that chloride levels present were below those recommended by the tank lining manufacturer.
Removing contaminants
It is very important that these contaminants if present are removed prior to preparation for the tank lining application by abrasive blasting, as the high pressure air can force them further into the steel surface.
The tank internals were then prepared by method of abrasive blasting to raise a surface profile of 75 microns or greater as recommended by the tank lining manufacturer. Stainless steel tanks can be a difficult surface to ensure tank linings adhere to, with abrasive blasting being the best way to ensure a consistent surface profile for optimum adhesion of any tank lining applied.
Vacuuming the tank internals
Following abrasive blasting and the removal of the spent blast abrasive, the tank internals were vacuumed clean to remove dust that would prevent proper adhesion of the new tank lining
To confirm the effectiveness of the cleaning operation the cleanliness of the surface was tested and recorded using an Elcometer 142 Dust Tape Test Kit to make an assessment in line with ISO 8502-3.
Coating and priming the surfaces
Heating and dehumidification was introduced to ensure that correct climatic conditions for tank lining application as per the Chemco Internationals recommendations.
All surfaces to be coated were then primed using Chemco Chem-Tect RC300P. This low viscosity vinyl ester tank lining primer ensures excellent adhesion by penetrating the surface profile and is specifically designed for bonding to difficult substrates such as stainless steel.
The primer was applied by brush and roller to work the material into the surface profile.
Following priming details such as welds and angles received a stripe coat of Chemco Chem-Tect RB364 applied by brush to ensure full film build in these areas where coatings pull thin through gravity and surface tension as per best tank lining practice.
Chemco Chem-Tect RB364 was then applied by method of airless spray to a minimum thickness of 1200 microns as per the manufacturers recommendations
Wet film thickness readings were taken during application and then verified by the taking of dry film thickness readings after initial cure
Then verified by the taking of dry film thickness readings after initial cure.
To check the lining for porosity the new tank lining was checked for pin holing using a DC Holiday tester – commonly called spark testing. A single pin hole in a chemically aggressive environment is a point of tank lining failure.
Any holidays identified were made good using the same material applied by brush.
Finally Chemco Chem-Tect TB300 TC was applied throughout the tanks. This is a highly chemical resistant vinyl ester top coat incorporating a wax for enhanced chemical resistance in tank lining applications.
