HIGH-TEMPERATURE MICROBIAL CORROSION IN THE CONDENSER OF A GEOTHERMALELECTRIC-POWER UNIT

Field and experimental growth of microbiologically influenced corrosio n at high temperatures in a geothermal electric power unit condenser i s discussed. Four chambers containing polished and disinfected 304L st ainless steel tubes were exposed for two, four, six, and eight months to the condenser environment at temperatures ranging from 150 degrees C at the inlet to 40 degrees C at the outlet. The tubes developed pitt ing where Desulfotomaculum Nigrificans and Desulfotomaculum Acetoxidan s colonies were clearly identified by biochemical tests. There were al so some indications of the presence of genus Desulfovibrio and genus T hermodesulfobacterium.(17) The characteristics of pitting were studied employing SEM-EDS techniques and optical microscopy.