Influences of Thermophilic Sulfate-Reducing Bacteria on the Corrosion of Carbon Steel at Different Temperature

Abstract

The growth and the corrosion behaviors of thermophilic sulfate reducing bacteria (SRB), desulfotomaulum thermocisternum strain ST90, were studied in this work. It was found that the growth curves and the main reduction products were influenced greatly by the growth temperatures. The time of the exponential phase and the stable phase decreased with the increase of growth temperatures. The reduction product of this kind of SRB was mainly H2S when it grew at 60°C. With the decrease of growth temperatures, thiosulfate came up as an internal reduction product. The thiosulfate was re-reduced by SRB at the growth temperatures of 40 and 50°C. When the growth temperature came to 30°C, no H2S was generated. The regulation of corrosion rate changed was coincident with the changes of the main reduction products of the SRB. This kind of SRB could accelerate the corrosion rate of carbon steel when grew at higher temperature. But the corrosion rate of carbon steel could be inhibited when it grew at 30°C.