Refurbishment of Nitrogen Tank

Updated: Mar 7, 2019

Our client, one of the worlds largest oilfield services companies, trusted Waterworth as it's corrosion partner in order to refurbish this Nitrogen tank. They understand that the condition of their equipment reflects on their company to their clients. The first step is preparing the work site in our operational base in Piasau, Miri and organizing logistics so that the tank can be safely offloaded from the truck.

Once the tank is in place we started with surface preparation, which mainly involves a grinder. The idea is to remove all sharp edges from which is a common location that corrosion begins. We would normally also grind welds with defects such as weld splatter, however in this case the welds were not ground because the DNV-approved frame was not to be modified in any way by clients request. Once the tank had been grinded and inspected for defects, blasting could commence.

We used our vapor blasting technology (aka. dustless blasting) in conjunction with GMA garnet. The abrasive ripped through the old paint in to time while leaving the surface of the steel rough like sandpaper. This roughness gives the coating an anchor so that it will bond with strength to the steel. Moreover the inclusion of Holdtight 102 into the blast-water means that all surface impurities such as salt and grease are completely clean. To confirm the suitability of the substrate for we conduct a chloride test and surface profiling which confirms that A) no salt is present on the surface, and B) the surface roughness is in accordance with the coating specifications.

Now that the tank is completely clean it is ready for painting. The first step in painting is known as 'stripe coating'. This step involves using a brush to brush all welds and areas where a very good bonding with the surface is required such as corners. The bristles from the brush physically push the coating into the crevices of the steel ensuring good adhesion. Once this step is complete, we used a high pressure spray painting system known as an airless spray pump to efficiently coat the entirety of the tank in 300 microns of Jotamastic 90 primer followed by 100 microns of Hardtop XP finishing coat.

Final steps before delivery to the client include polishing of all the stainless steel, application of brand new stickers, re-greasing of bolts and fittings, and cutting gaskets to put between areas where stainless steel and mild steel are touching (to prevent galvanic corrosion).