Inhibitor Protection of Steel Against Corrosion and Scaling Under the Influence of Ultrasound
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INHIBITOR PROTECTION OF STEEL AGAINST CORROSION AND SCALING UNDER THE INFLUENCE OF ULTRASOUND N. А. Bilousova,1, 2 Yu. S. Herasymenko,1 R. М. Red’ko,1 H. S. Vasyl’ev,1 and V. І. Vorobiova1
UDC 620.197.3
We study the combined action of reagents and ultrasound on corrosion and scaling under the conditions of operation of water-heating equipment at a temperature of 95 ± 2°С and under atmospheric pressure. The efficiency of a known agent (oxyethylidene diphosphonic acid) and a “green” inhibitor based on the extract of rapeseed oil meal is found in high-hardness water both under the conditions of their individual action and in combination with ultrasonic irradiation of the medium in the subcavitation mode. The scaling (according to the mass increments) and corrosion (by the method of polarization resistance) rate are determined on the same samples. The functional time dependences of the specific scaling and corrosion rates are obtained under the conditions of reagent, ultrasonic, and combined treatment of water. It is shown that ultrasound exerts a negative influence on the antiscale properties of the investigated reagents by decreasing the efficiency of action of the antiscalant. A protective anticorrosion film is formed on the steel surface with time, as follows from the behavior of the corrosion rate, which sharply decreases in the initial period of the tests and then stabilizes on a level of 0.02 mm/yr. It is demonstrated that the complex influence of antiscalants and ultrasound in certain modes of treatment of the medium makes it possible to optimize the formation and preservation of a phase microlayer with antirust properties, which exerts almost no influence on the heat exchange between the metal surface and the heat carrier. Keywords: corrosion rate, scale, ultrasound, inhibitor, antiscalant, “green” inhibitor, extract of rapeseed-oil meal.
Introduction The corrosion processes running in the heat-exchange equipment lead to its premature failures and deterioration of the quality of heat carriers. Thus, they can be regarded as the main cause of unscheduled costs spent for the maintenance and replacement of heat-exchange installations. At the same time, scaling causes an increase both in the heat and hydraulic losses and, hence, in the prime cost of the thermal energy. Moreover, it is also responsible for the damage to heat-exchange surfaces caused by overheating. Thus, as the optimal solution, we can offer the simultaneous application of the methods of chemical (reagent) [1–3] and physical (ultrasonic) treatment [4–8], which would make it possible to control the formation of a phase microlayer with antirust properties, which exerts almost no influence on the heat exchange between the metal surface and the heat carrier. 1 2
“Sikorsky Kyiv Polytechnic Institute” National Technical University of Ukraine, Kyiv, Ukraine. Corresponding author; e-mail: [email protected].
Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 55, No. 6, pp. 49–56, November–December, 2019. Original article submitted March 14, 2019
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