Peracids are multifunctional chemistries that are an equilibrium mix between an organic acid and peroxide. Peracids are widely used as biocides in oil and gas, food and beverage, health care and other industries. In addition to its use as a biocide, peracids are often used for iron sulfide scale dissolution and hydrogen sulfide control.
The performance of peracids as a biocide is dependent on many factors. These factors include the presence of other oxidizable species, temperatures, salinity as well as the metallurgy of the treatment setup. Compatibilities of SS430 and SS304 alloys were evaluated with high peroxide and low peroxide formulations of peracetic acid solutions in the presence of chlorides (0.9% weight). Effect of biofilm on the alloys was evaluated prior and post peracetic acid treatments. Anodic cyclic polarization, electrochemical impedance spectroscopy and surface analysis were used to evaluate the factors that affect the corrosion on metallurgies under treatment conditions. The results suggest that irrespective of the metallurgy, peroxide concentrations in peracid formulations is a key parameter that must be accounted for to determine corrosion potential and provide a strategy for application of these products on different metallurgies.
Biocides also known as antimicrobials are often used to control problematic microorganisms in the oil and gas industry. Uncontrolled microbial populations can cause severe asset integrity and safety issues including fouling and release of H2S. 1,2
Efficacy testing of antimicrobial products involves two types of microbial kill studies; planktonic and sessile tests. Planktonic tests are performed either using a native set of microorganisms or a test microorganism (like Pseudomonas aeruginosa) suspended in a test fluid. For sessile testing, microorganisms are grown as a biofilm on a coupon, typically in a bioreactor. In either of these cases, the performance of a biocide is tested using a variety of techniques including ATP quantitation, confocal microscopy as well as using outdated techniques like bug bottles.3