Do you need a deaerator in communal and domestic heating systems?

In our publications on industrial and municipal heating systems, the deaeration process was mentioned and related equipment. The deaerator is present mainly in Russian-language engineering schemes and is not typical for Western projects. It is also excluded when designing compact boiler rooms that operate, inter alia, on the basis of solid fuel boilers FOCUS and pellet burners our brand.

The deaerator is used in two qualities:

• to ensure a supply of water in the system and supply it to the make-up unit;
• for the purpose of cleaning liquid from gaseous impurities.

The presence of such a unit is focused on the uninterrupted operation of a communal boiler house in critical conditions. When, for example, there is no water for the make-up system coming from the outside. Considering when such a situation may arise, the installation of deaerators is advisable for municipal and industrial boiler houses. Deaeration also helps to increase equipment life and reduce the effects of corrosion in the system.

Deaerator designs

Deaeration tanks can be different in design. There are vertical and horizontal models offered by manufacturers. The most common deaerators of the disc and spray type.

Disc deaerator

The first type structurally combines a horizontal and vertical tank. The design assumes the separation of the two technological processes. Untreated water is fed into the vertical tank, where it passes through filters and, under the influence of gravity, flows into the tank of finished drinking water. Recall that in open systems not technical, but drinking water is used as a heat carrier.

The deaeration process itself takes place in the presence of steam, which is introduced through perforated gaskets. Under its influence, the gas dissolved in water passes into the gas-vapor phase, the so-called vapor, which is discharged through the vent hole.

After the deaeration process, water is drained into a horizontal tank, from where it is fed to the heating and hot water system. Many deaerator designs also involve bubbling in a horizontal tank. In addition, this process allows you to maintain the design temperature in the tank. Due to the need to maintain the water temperature, deaerators are usually thermally insulated.

Spray deaerators

A deaerator of this type has only a horizontal tank, separated by a partition. The chamber has a storage and deaeration area. The feed water for the heating medium is heated by mixing with steam from a steam manifold located at the bottom of the tank. The evolved gases are removed through the ventilation system. Waste gases are also used for water recovery. This involves installing a special valve in the ventilation system.

The principle of operation of a spray type deaerator is associated with the accumulation of gas in water. It can be present in the following forms:

• dissolved;
• as microbubbles that form around hydrophobic inclusions;
• as part of the gas released during deaeration.

According to physical processes taking place in thermodynamic media, gases can be replaced in water by steam. In practice, the question of the required degassing depth is open and debatable. In other words, after deaeration, residual dissolved gases in all of the listed types remain in the water, but their volume decreases.

In addition to the proposed processes, partial deaeration of water can be achieved when treating water with ultrasound. Also, deaerators may differ in the design of vapor removal, that is, gases released from water.

The useful capacity of the deaerator tank is usually 85%.

Water storage tank as an analogue of deaerators in autonomous household systems

The presence of a container for storing drinking water is advisable in autonomous water supply systems of rural houses and farms. Especially in cases where purified rainwater is used for domestic purposes. In this case, a pre-filtered liquid is supplied to the storage tank, which is subsequently used for hot and cold water supply. It is also used to feed the heating system.

The presence of a water storage tank is also useful if an Abyssinian well or well is used for water supply at home, where various contaminants are not excluded. At the same time, the preparation of potable water takes time to filter. For this reason, depending on the peak moments of consumption, the water coming from the well may not be enough, it comes from the make-up tank with ready water.

Ultrasonic cleaning can be used to filter and remove harmful gases from water in homes located in regions with high environmental stress. At the same time, the presence of a potable water tank, an analogue of a deaerator, in household systems is advisable if well water is also used as a source. This solution is less costly than the device of your own well, the water quality in which may not be so satisfactory and requires additional treatment with filters.

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