Identification of microbiologically influenced corrosion (MIC) in industrial equipment failures

The present study demonstrates different approaches towards MIC identification in three real cases of technological equipment failures. In the first case the failure of carbon steel heat exchanger as a result of tubes, lids, tube sheets, and connection pipes clogging was investigated. Chemical analysis of cooling water and precipitates, as well laboratory screening of deposits for bacteria, revealed that activity of iron-oxidizing bacteria present in cooling water led to heat exchanger blockage. The second case is related to MIC detection on floating roofs made of magnesium-aluminum alloy following a 3-weeks hydro-test. Corrosion tests carried out on the original and sterilized water used in hydro-test confirmed MIC process. In the third case the potential of MIC occurrence in engine cooling system made of cast aluminum alloy and filled with 20% ethylene glycol coolant solution was evaluated. The simulation tests allowed determining the real causes of the severe corrosion attack of examined system, including MIC high probability. (c) 2007 Elsevier Ltd. All rights reserved.