Novel Internal Coating System for High Concentration H2S Environments

Traditional internal coating systems relied on phenolic, novolac, epoxy or blended resin systems. These tended to provide good barrier properties in the environments they were developed for, but as with all materials, there were limitations. One of those limitations that had to be overcome during the development and application process was that during the curing process, they can tend to shrink, so greater surface preparation processes must be followed to ensure that the system adhesion far outweighs the residual stress in the coating system. In sweet applications, this residual stress offers little to no effect on a properly applied coating system provided its design parameters are not exceeded. In the presence of higher concentrations of hydrogen sulfide, there can be a negative effect on the adhesion of most of these resin type coating systems allowing the residual stress to play a role in blistering and disbondment. A new and novel resin system has been developed that does not shrink during the curing process and can be applied as a primer-less system. Coatings developed with this new resin, benzoxazine, allows the coating system to maintain good adhesion and barrier properties in H2S concentrations two to three times greater than the current leading H2S resistant coating systems on the market today. This paper is the second in a series on the development of this product into a coating solution. Further laboratory refinement will be discussed leading to the next phase of the roll-out which will be field trials.