Mitigation Strategies for Microbiologically Influenced Corrosion in Gas Industry Facilities

Abstract

Abstract A study of microbiologically influenced corrosion (MIC) and its mitigation in gas industry facilities, sponsored by the Gas Research Institute, was conducted during 1986-88. The results show that MIC commonly occurs on both external and internal surfaces of pipes, in down hole tubulars and in process equipment such as separators. Mitigation strategies were tested in side-stream devices at several sites. The results demonstrate that many biocides and corrosion inhibitors are relatively ineffective in controlling the surface microbial populations, at least under the conditions of the tests. Detailed studies with glutaraldehyde demonstrated that reestablishment of surface MIC communites after removal of this biocide was very rapid. Continuous treatment with glutaraldehyde led to the development of surface microbial communities "resistant" to the effects of the biocide. Intermittent treatment with glutaraldehyde, when applied frequently enough, effectively controlled the surface MIC populations. Heat treatment was very effective and might be used in some facilities (e.g., separators) to prevent inputs of large amounts of MIC bacteria into pipelines. The results of field investigations of external MIC of buried gas pipelines are summarized and possible mitigation measures discussed.