EVALUACIÓN DE LA EFICIENCIA DE BIOCIDA COMO INHIBIDOR DE LA CORROSIÓN INDUCIDA POR MICROORGANISMOS

Abstract

The general aim of the present work was to evaluate the efficiency of the commercial biocide named THPS or bis [ (tetrakis (hydroxymethyl) fosfonio] sulfate, on the corrosion induced by microorganisms, specifically the type induced by sulfate reducing bacteria (SRB). Electrochemical tests in media prepared with and without THPS were carried out to determine the corrosion rate and the inhibiting efficiency of the product. In addition, a morphologic study (SEM and EDS) of the exposed surfaces was conducted in order to determine the surface morphology of the corrosive attack, as well as the composition and distribution of the corrosion products. The above mentioned, was carried out since in spite of the intensive use of inhibitors in the production of oil, in most cases the mechanism of action towards the steel microconstituent is not known. The evaluation results showed that THPS turned out to be effective in the control of BSR's growth. A preferential action towards the protection of pearlític regions in the J55 steel was observed and this was possibly due to the structural heterogeneity of the pearlitic formations, which facilitate the nucleation and fixation of THPS crystals thus inhibiting the bacterial action. Nevertheless, in the waters without THPS, the same pearlitic zones were preferential sites for niches formations of bacterial habitats, may be due to the rough topography and morphology of these regions which constitute a perfect surface for the anchorage of the bacterial microorganism and their metabolic products.