Investigation of Corrosion Behavior of Drain Pipes of Process Compressors in Direct Reduction Unit.

Corrosion is a natural process in the destruction of industrial components. Corrosion can be intensified and finally led to destruction where there are temperature increase and microbial agents in addition to the main causes of corrosion. Process compressors were employed in order to meet the gas pressure and flow of the process in the direct reduction unit, and carbon steel pipes were used to separate water from the gas. However, these pipes are punctured and leak water and gas in less time in comparison with the other units. In order to examine the destruction reasons, several samples of the destructed pipe were provided, and they were studied by scanning electron microscopy (SEM) and EDS. The results showed that, besides regular agents like high temperature and acidic medium, microbial corrosion by sulfate-reducing bacteria and H2S gas effect lead to intensifying local and sub-sediment corrosion so that the component will be destructed in less time. The presence of FeS layer will result in severe local corrosion.