Features of the operation of cold and hot water supply systems regarding the corrosion activity of zinc-plated pipes in water supply
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Дата
2024
Науковий керівник
Назва журналу
Номер ISSN
Назва тому
Видавець
КПІ ім. Ігоря Сікорського ; ТОВ «Українська водна спілка»
Анотація
The exploitation of zinc-plated household water supply systems is associated with the problem of the development of local corrosion processes on the inner surface of steel pipes. Research on this topic is quite relevant, as evidenced by the analysis of articles on short-term use of zinc-plated pipes in water supply systems. The work presents aspects of consideration of the influence of water treatment, operational parameters and the presence of zinc coating on the performance of the system from the point of view of the development of local corrosion processes. The need for control by comparing water quality indicators "before and/or after water treatment" and "water in the system", was highlighted. This makes it possible to detect an aggressive corrosive environment already at the beginning based on the indicators of dissolved oxygen, free carbon dioxide and the index of equilibrium saturation of water with calcium carbonate and to establish the state of the inner wall ("active / passive") based on the presence of an increased concentration of iron, oxygen, and zinc ions. It was established that the presence of molecular oxygen dissolved in tap water in the hot water supply system in the temperature range of 60...70 ºC leads to the loss of protective properties by zinc due to the formation of a surface passive film of the ZnO, which leads to a shift in the corrosion potential of zinc to a more positive region, compared to the protective potential of iron, values. Cold water supply systems are characterized by the electrochemical nature of corrosion processes with oxygen cathodic depolarization. On top of that, the inadmissibility of direct contact of zinc-plated pipes with fittings elements and shut-off valves that made of brass, bronze and copper due to the destruction of the metal wall of the pipes due to the contact corrosion, has been proven - the potential difference of these galvanic elements is from 0.570 to 0.854 V.
Опис
Ключові слова
water supply system, tap water, water quality, corrosion, zinc-plated pipes, electrochemical research, система водопостачання, водогінна вода, якість води, корозія, оцинковані труби, електрохімічні дослідження
Бібліографічний опис
Klymenko, A. Features of the operation of cold and hot water supply systems regarding the corrosion activity of zinc-plated pipes in water supply / A. Klymenko, S. Kovalenko, Yu. Kovalenko // Вода і водоочисні технології. Науково-технічні вісті. – 2024. – № 1(38). – С. 47-60. – Бібліогр.: 32 назви.