Basics of the water chemical mode of low-pressure steam boilers |

In the article, as simply as possible (as it seems to the author), the basics of the water-chemical mode of low-pressure fire-tube steam boilers are presented.

The water-chemical mode (WCM) of a steam boiler is an operating complex of technological solutions aimed at ensuring trouble-free and efficient operation of a steam boiler.

In fact, it is quite easy to achieve an efficient functioning of a steam boiler. To begin with, the main thing is not to drown in incorrect and ineffective (and sometimes harmful) information, which currently fills the entire information space.

First, a few words about water. Water has the property of entering a state of equilibrium with the surrounding system or with the conditions surrounding it. That is, the water in a river comes into contact with air, land, groundwater, and surface runoff. As a result, a certain balance is achieved between water and the conditions surrounding it. In the process of achieving this equilibrium, water can dissolve various substances in itself. For example, water is saturated with carbon dioxide from the air or from organic oxidation processes (decay). As a result, the water becomes acidic and begins to dissolve limestone. By dissolving limestone, the water is getting saturated with calcium bicarbonate while increasing the pH value is increasing. Therefore, water contains various types of ions and at the same time it has a complex gas composition. And all of these are in balance for the given environment. If, for example, you calculate the Langelier index for a full-flowing river, it turns out that it will always be around zero.

Now let us imagine that this water enters the boiler. The environment is changing. The water heats up, begins to boil, and all gases, including carbon dioxide, are  actively being removed from it. As a result, reaching a new equilibrium for the given environmental conditions, the water begins to release ions and organic matter in the form of scale and sludge. At the same time, heating increases the mobility of oxygen and therefore increases the corrosive activity.

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