Кочмарський, В. З. та Костюк, О. П. та Тимейчук, О. Ю. та Kochmarskii, V. Z. та Kostiuk, O. P. та Tymeіchuk, O. Y. (2021) ВІДКЛАДЕННЯ У ВОДОГРІЙНИХ КОТЛАХ ТА ЇХ НАСЛІДКИ. Вісник Національного університету водного господарства та природокористування (3(95)). с. 57-66.

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Анотація

Аналізуються проблеми експлуатації котельних установок, зокрема водогрійних котлів, що пов’язані з утворенням карбонатних та комбінованих відкладень з водної сторони їх трубних систем (ТС). Досліджуються умови, за яких утворюються відкладення на ТС в котлах навіть при штатній роботі систем водопідготовки. Оцінюється коефіцієнт теплопровідності відкладень з врахуванням їх реальної структури. Досліджується вплив відкладень на коефіцієнт теплопередачі ТС.

Title in English

DEPOSITS IN HEATING BOILERS AND THEIR CONSEQUENCES

English abstract

The problems of operation of boiler installations, in particular hot water boilers, which are connected with the formation of carbonate and combined deposits on the water side of their pipe systems (PS) are analyzed. The conditions, under which deposits are formed on the vehicle in boilers, even during the regular operation of water treatment systems, are studied. The coefficient of thermal conductivity of deposits is estimated taking into account their real structure. The influence of deposits on the heat transfer coefficient (HTC) of the pipe system of boilers is investigated. It is shown that during the regular operation of water treatment, deposits on the vehicle can be formed due to their erosion in the network and re-allocation on the pipe system of the boiler in the area of elevated temperature. Preferably the deposits have a layered structure. Closer to the walls of the tubes, they are in the form of dense deposits of CaCO3, and externally in the form of a porous structure. The thermal conductivity of such a layered system is calculated. For porous deposits, it is proposed to calculate according to Maxwell's formula and it is calculated the equivalent thermal conductivity of successive layers. An expression for the HTC of a contaminated pipe system is obtained. It is shown that a layer of carbonate deposits with a thickness of 1 mm reduces HTC by 36%.The expression for the pollution coefficient (PC) is calculated. It is shown that the value of the PC is proportional to the product of the thermal resistance of the contaminants on the HTC of a clean boiler. Therefore, boilers with high HTC are more sensitive to contamination. As the PC grows, the logarithmic temperature difference on the vehicle increases sharply. Deposits are especially dangerous for boilers operating in the mode of constant heat supply to consumers with the set temperature of water heating. In this case, pollution is accompanied by fuel overheating with all the negative consequences. The expressions obtained in the work can be useful in determining the timing of the withdrawal of boilers for cleaning. To minimize deposits, it is proposed to do periodic purification of mains water from Ca2+ and СО32- ions and stabilization treatment of mains water.

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