Specific Features of Biocorrosion of the Circulation Cooling System in the Petrochemical Industry

Abstract

The circulating water of the cooling systems of petrochemical enterprises has a number of special features: the temperature of cooling water is in the range of 14-28 °С all year round, the evaporation of water in cooling towers increases the concentration of dissolved salts. Inevitable ingress of hydrocarbons, dosing of corrosion inhibitors, scaling, reagents for dispersing and softening of the water creates favorable conditions for micro- and macroorganisms development. Existing standards stipulate that the number of viable bacterial cells in planktonic form should not exceed 10 cells/ml, the number of bacteria in the adhered form is not regulated, nevertheless these organisms in particular lead to biocorrosion. During the assessing of the biological degradation of water cycle equipment materials, it was studied the micro- and macroorganisms that populate the surface of steel samples 20. Studies of the effect of this bacteria on the corrosion of steel 20 showed that this whole complex of micro- and macroorganisms, releasing metabolites into the water, also indirectly affects the processes of corrosion, and when choosing protection methods, it is necessary to take into account not only the presence and types of bacteria, but also the entire local biocenosis.