Sustainable, Long-Term Solution For MIC/SRB Corrosion In Hydrocarbon, Other Pipeline Systems

U-TECH
By Kent Weisenberg | July 2010 Vol. 65 No. 7
The MIC/SRB corrosion was a severe problem.

MICs are an aerobic species (requiring oxygen for survival) such as slime-forming bacteria, also referred to as a biofilm, which colonize the layer. Once the biofilm has reached a certain thickness, SRBs colonize beneath the biofilm and locate themselves at the interface between the biofilm and the metal substrate. SRBs are anaerobic (thriving in oxygen-deficient environments) and therefore locate themselves at the interface, where they are protected from the aerated water of the biofilm. The MICs use the available oxygen within the biofilm; the base of the biofilm is anaerobic.

insparart3.jpg
The Inspar process.

It is essential to note that the survival of both types of bacteria requires the presence of water. They therefore cannot be active in non-aqueous media or environments.

Due to the difficulty of removing SRBs once they have become established, simply injecting biocides into the slurry is ineffective because the bacteria is located beneath the tubercles. To expose the bacteria, the scale and tubercles must be removed, which Inspar achieved by using helically-wound wire pigs, followed by rotational water jetting.

As a pre-treat to the prepared carbon steel, Inspar used a proprietary chemical compound developed by Planet Resource Recovery Inc. This compound can render the cavernous pits of metal impervious to oxygen and biological penetration within surface bonding. It forms ionic bonds with metal at the nano scale level and fills the micro crevices on metal surfaces, rendering a smoother coefficient that is impervious to bacterial and oxygen threats. Inspar utilizes this method because it is not simply an ‘additive’ to attempt to kill the microbial agents, but is actually a catalyst for changing the molecular structure of the metal.

insparart4.jpg

The basic issue with most of today’s simple ‘additive’ treatments has been the lack of permanency. One of the primary attributes of the Inspar polyurea-based lining systems is the extreme durability and performance expectations of their lining products. It is difficult to justify applying a product or system that will last over half a lifetime and then improving the system with anti-microbial characteristics that might last only a year at best. Most ‘anti’ additives contain heavy metals that impair microbe viability. These additives tend to migrate to the surface of the coatings and are then washed or abraded away after a relatively short period of use, therefore requiring a continuous replenishment program.