In order to achieve durability and quality of work hydraulic system a deaerator must be used. It is used in all boiler houses, as it establishes stable and correct work systems. In our article we will look in more detail at what a deaerator is in a boiler room.

What is a deaerator and why is it used in a boiler room?

Deaeration is the process of purifying a liquid from various impurities. For example, from carbon dioxide and oxygen. To organize a water treatment system in a boiler room, a deaerator must be used. It helps improve the quality of work.

The first method is chemical deaeration. In this case, reagents are added to the water, as a result of which excess gases are removed from the water. The second method is called thermal deaeration. Water is heated to a boil until it is cleared of gaseous substances that have dissolved in it.

Deaerators are divided into atmospheric and vacuum. The first ones are used with water or steam. And vacuum ones only use steam.

Deaerators have a common two-stage device. Thus, water enters the tank, where it flows through membranes and is then purified of impurities. The chemical water that is in the tank prevents the formation of various natural impurities in the coolant.

Deaerators come in low and high blood pressure. Since oxygen and carbon dioxide belong to aggressive gases, they contribute to the formation of corrosion in pipelines and also wear them out. To prevent this from happening, it is necessary to prepare it before supplying water through pipelines. This is exactly what deaerating filters are used for.

Due to gas contamination of water, various malfunctions occur in the system. Some of them can lead to water or gas leaks or completely damage the system. The presence of gas bubbles in water leads to poor performance of pumps and nozzles and impairs the functions of the hydraulic system. Installing a deaerator in a boiler room will be cheaper than frequently repairing the system.

Deaeration of water in a steam boiler room

Deaeration of water in a steam boiler room is necessary to protect the entire steam generator system and pipelines. If harmful impurities are present, the system will wear out and begin to corrode.

Gaseous and natural impurities can cause pump cavitation. And this, in turn, can lead to water hammer and disrupt the operation of the pumping mode. In the worst case, the hydraulic system may rupture or the pumps will stop working altogether.

The deaerator, which is used for a steam boiler, has the form of a tank with special membranes and plates. They are arranged vertically on a water tank. Under low pressure, water flows from the supply line into the tank, then flows through membranes and plates and thus removes impurities.

Sometimes spray deaerators are used in steam boiler houses. In them, water is sprayed in such a way that impurities immediately evaporate.

Pressure system

The high pressure system is used for boilers with high power. They supply a lot of steam and also provide the necessary temperature regime for centralized heating system under high pressure. For the system to function, pressures above 0.6 MPa are required.

This installation is thermal in the same way as a reduced pressure deaerator. This means that when the temperature of the water and steam supply increases, the system is freed from gaseous impurities.

Water seals are installed in the system. They lower blood pressure if it rises.

Reduced pressure system

For a reduced pressure system, atmospheric and vertical type, which are equipped with a bubbler additional tank. Evaporation occurs through it.

In the main tank of the system, the chemically prepared mixture is mixed with water, then it flows through membranes and plates and then all impurities are separated.

Boiler houses that provide hot water require a vacuum thermal system. Since vacuum degassing is best suited for such a boiler room. This system is used to purify water in water heating boilers.

Depending on the required steam supply mode for steam boilers, high or low pressure deaerators are used. For less powerful boiler houses that provide low temperature conditions, which are suitable for central heating, use a reduced pressure installation. It can be 0.025-0.2 MPa.

Correct operation

For high-quality operation of the boiler and to prevent emergency situations, it is necessary to use the deaerator and the entire system correctly. To do this, it is necessary to maintain the water in the tank at a certain level when the pressure decreases, check the conditions of the required mode, follow all rules of use and check the operation of the devices more than once per shift.

In chemical water, it is necessary to correctly add substances, as well as monitor their levels. Check the quality of chemical water.

Water seals must move easily. If the pressure increases, they must be used without any interference. All devices must be metrologically certified and tested. They must adhere to pre-established schedules. The water level can be monitored using a special water indicator glass. Do not forget about monitoring the pressure gauge readings.

All automation devices must work properly for the deaerator to function properly. It is necessary to check the operation of machines and devices. To achieve this, regular inspections and checks are carried out.

The deaerator acts as protection for the entire boiler system. Therefore, every boiler room is equipped with such an installation.

Since cavitation leads to failure of the pump and hydraulic system, a deaerator is simply necessary in the boiler room. This device completely purifies the water from all impurities. This way the system works without any damage.

N.N. Gromov, chief engineer of AP "Teploset" Krasnogorsk region

Last time a large number of steam boilers (DKVr, DE, E, etc.) are switched to hot water mode, while the boiler room deaerators remain without steam. Effective method, developed and tested for 10 years in AP “Teploset” of the Krasnogorsk region, allows you to degas water without altering the deaerator without steam supply and without disadvantages vacuum deaeration.

Thermal deaeration

Water always contains dissolved aggressive gases, primarily oxygen and carbon dioxide, which cause corrosion of equipment and pipelines. Corrosive gases enter the source water as a result of contact with the atmosphere and other processes, such as ion exchange. The main corrosive effect on metal is oxygen. Carbon dioxide accelerates the action of oxygen and also has independent corrosive properties.

To protect against gas corrosion, deaeration (degassing) of water is used. The most widespread is thermal deaeration. When water is heated at constant pressure, the gases dissolved in it are gradually released. When the temperature rises to the saturation (boiling) temperature, the concentration of gases decreases to zero. Water is freed from gases.

Underheating of water to the saturation temperature corresponding to a given pressure increases the residual content of gases in it. The influence of this parameter is very significant. Underheating of water even by 1 °C will not allow achieving the requirements of the “Rules...” for feed water of steam and hot water boilers.

The concentration of gases dissolved in water is very low (on the order of mg/kg), so it is not enough to separate them from the water, but it is also important to remove them from the deaerator. To do this, it is necessary to supply excess steam or vapor to the deaerator, in excess of the amount required to heat the water to a boil. At total consumption steam is 15-20 kg/t of treated water, evaporation is 2-3 kg/t. Reduced evaporation can significantly degrade the quality of deaerated water. In addition, the deaerator tank must have a significant volume, ensuring that water remains in it for at least 20 ... 30 minutes. Long time necessary not only for the removal of gases, but also for the decomposition of carbonates.

Atmospheric deaerators with steam supply

For deaeration of water in boiler rooms with steam boilers Mostly thermal two-stage atmospheric deaerators (DSA) are used, operating at a pressure of 0.12 MPa and a temperature of 104 °C. Such a deaerator consists of a deaeration head having two or more perforated plates, or other special devices, thanks to which the source water, breaking into drops and jets, falls into the accumulator tank, encountering steam moving countercurrently on its way. In the column, water is heated and the first stage of its deaeration occurs. Such deaerators require the installation of steam boilers, which complicate thermal diagram hot water boiler house and chemical water treatment scheme.

Vacuum deaeration

In boiler rooms with hot water boilers As a rule, vacuum deaerators are used, which operate at water temperatures from 40 to 90 °C.

Vacuum deaerators have many significant shortcomings: high metal consumption, a large amount of additional auxiliary equipment(vacuum pumps or ejectors, tanks, pumps), the need to be located at a significant height to ensure the operation of make-up pumps. The main disadvantage is the presence of a significant amount of equipment and pipelines that are under vacuum. As a result, through the shaft seals of pumps and fittings, leaks in flange connections and welded joints, air enters the water. In this case, the deaeration effect completely disappears and it is even possible to increase the oxygen concentration in the make-up water compared to the initial one.

Atmospheric deaeration without steam supply

Recently, a large number of steam boilers have been switched to hot water mode. Effective method deaeration in boiler houses with such boilers was developed and passed a long test at the AP "Teploset" of the Krasnogorsk region.

The water after the sodium cation exchanger is heated to 106-110 °C and injected into the head of the atmospheric deaerator, where water droplets boil due to a decrease in pressure. When boiling, corrosive gases are removed from water along with steam, more actively than in deaerators with steam supply. The scheme was implemented on equipment that was operated in a steam boiler house with three DKVR 10/13 boilers, when switched to water heating mode with coolant parameters of 115/70 °C. In this case, the DSA type deaerator does not require modifications. To heat the make-up water, steam network heaters were used, modified to operate on heating water with a temperature of 110-113 °C, and not on steam. On technical solutions, used in boiler houses of the Krasnogorsk region, a patent of the Russian Federation was received.

This scheme eliminates the disadvantages of vacuum deaeration and deaeration with steam supply. The advantage of the new deaeration scheme is its simplicity and reliability, allowing it to operate stably in any hot water boiler house.

Besides

When switching DKVR 10/13 boilers with coolant parameters of 115/70 °C to water heating mode according to the TsKTI scheme, we encountered a decrease in the heating output of the boiler unit (it does not decrease with the 150/70 schedule). Such a reduction was unacceptable in terms of the load on the heating network, so we developed and implemented changes to the TsKTI scheme. Structurally, the changes are not significant, but they made it possible to improve circulation in the rear screens and increase the heating output of the boiler to the required level. The pattern of water movement in the boiler circuit is patented. The boilers have been in operation for 10 years without any complaints.

Atmospheric pressure deaerators are designed to remove corrosive gases (oxygen and free carbon dioxide) from the feed water of steam boilers and the make-up water of heating supply systems and in the boiler room.

Example symbol deaerator

DA-5/2
Where: YES - atmospheric deaerator;
5 - column productivity m³/h;
2 - tank capacity m³;

Technical characteristics, completeness and types of Deaerators

Options
Productivity, t/h	5	5	15	15	25	25	50	50	100	100	100
Productivity range, t/h	1,5-6	1,5-6	4,5-18	4,5-18	7,5-30	7,5-30	15-60	15-60	30-120	30-120	30-120
Working pressure, MPa	0,02
Temperature of deaerated water, °C	104,25
Average water heating in the deaerator, °C	10..50
Column		KDA-5		KDA-15		KDA-25		KDA-50		KDA-100	KDA-100
Weight, kg	210	210	210	210	427	427	647	647	860	860	860
Tank			BDA-4		BDA-8		BDA-15		BDA-25
Tank capacity, m³	2	4	4	8	8	15	15	25	25	35	50
Weight, kg	1100	1395	1395	2565	2565	3720	3720	5072	5072	7046	9727
Vapor cooler		OVA-2	OVA-2	OVA-2	OVA-2	OVA-2	OVA-2	OVA-2		OVA-8	OVA-8
Heat exchange surface area of ​​the vapor cooler, m2	2	2	2	2	2	2	2	2	8	8	8
Weight, kg	232	232	232	232	232	232	232	232	472	472	472
Safety device		DA-25	DA-25	DA-25	DA-25	DA-25		DA-50		DA-100	DA-100
Weight, kg	277	277	277	277	277	277	401	401	813	813	813

Design and principle of operation of the deaerator
The deaerator includes:
- deaeration column;
- deaerator tank;
- vapor cooler;
- combined safety device for protection against emergency increases in pressure and level.

The deaerator uses two-stage scheme degassing: two stages are located in the deaeration column: the 1st stage is jet, the 2nd is bubbling.

Fig 1. Diagram of an atmospheric pressure deaeration plant type DA

1 - Deaerator tank; 2 - Deaeration column; 3 - Vapor cooler; 4 - Safety device; 5 - Level regulator; 6 - Pressure regulator; 7 - Sampling refrigerator; 8 - Bubbler device; 9 - Bubbler plate; 10 - Bypass plate; 11 - Upper plate; 12 - Steam transfer device; 13 - Level indicator; 14 - Manhole.

The deaerator tank contains a third, additional stage in the form of a submerged bubbling device.

Water to be deaerated is supplied to the column(2) through fittings (A, 3, I, D). Here it successively passes through the jet and bubbling stages, where it is heated and treated with steam. From the column, water flows in streams into the tank, after holding in which it is discharged from the deaerator through the fitting (G).

The main steam is supplied to the deaerator tank through a fitting(E), ventilates the vapor volume of the tank and enters the column. Passing through the holes of the bubble plate (9), the steam subjects the water on it to intensive processing (the water is heated to saturation temperature and micro quantities of gases are removed). When the heat load increases, the water seal of the steam bypass device (12) is activated, through which steam is transferred into the bypass of the bubbler plate. When the heat load decreases, the water seal is filled with water, stopping the steam bypass.

From the bubbling compartment, steam is directed to the jet compartment. In the jets, water is heated to a temperature close to the saturation temperature, the bulk of gases are removed and most of the steam condenses. The remaining vapor-gas mixture (vapor) is discharged from the upper zone of the column through fitting (B) into the vapor cooler (3) or directly into the atmosphere. The degassing process is completed in the deaerator tank (1), where tiny gas bubbles are released from the water due to sediment. Part of the steam can be supplied through a fitting into a bubbling device (8) located in the water volume of the tank, designed to ensure reliable deaeration (especially in the case of using water with low bicarbonate alkalinity (0.2...0.4 mEq/kg) and high content of free carbon dioxide (more than 5 mg/kg) and with sharply variable deaerator loads.

Design internal devices deaeration column provides convenience of internal inspection. Perforated sheets of internal devices are made of corrosion-resistant steel.

A surface-type vapor cooler consists of a horizontal body and a pipe system located in it (the pipe material is brass or corrosion-resistant steel).

Chemically purified water passes inside the tubes and is directed to the deaeration column through fitting (A). The steam-gas mixture (vapor) enters the annulus, where the steam from it is almost completely condensed. The remaining gases are vented to the atmosphere, and the vapor condensate is drained into a deaerator or drain tank.

To provide safe operation deaerators are protected from dangerous increases in pressure and water level in the tank using a combined safety device.

The device is connected to the deaerator tank through the overflow fitting.

The device consists of two water seals, one of which protects the deaerator from exceeding permissible pressure, and the other from a dangerous increase in level, combined into a common hydraulic system and an expansion tank. The expansion tank serves to accumulate the volume of water (when the device is activated) necessary for automatic filling of the device (after eliminating the malfunction of the installation), i.e. makes the device self-priming.

The diameter of the steam hydraulic seal is determined based on the highest permissible pressure in the deaerator when the device is operating, 0.07 MPa, and the maximum possible steam flow into the deaerator in an emergency with the control valve fully open and the maximum pressure in the steam source.

Installation and procedure for installing the deaerator
Before installing the deaerator it is necessary to: carry out inspection and re-preservation; Cut off the welded plugs with gas, and cut the edges of the pipes for welding.

1. It is preferable to place the deaerator indoors. Installing it outdoors is permitted in justified cases (by decision of the design organization).

2. The deaerator tank is installed strictly horizontally on a pre-prepared concrete foundation (with installed anchor bolts), or on a metal shelf. One support is rigidly secured with bolts, the second is freely supported on the support sheet.

3. The deaeration column is installed on the tank by welding to the adapter fitting. The column can be oriented arbitrarily relative to the vertical axis, depending on the specific installation layout.

4. Installation diagram of the deaerator, component equipment and their piping, as well as diagram and control devices and automatic regulation determined by the design organization depending on the conditions, purpose and capabilities of the facility on which they are installed.

5. Scheme deaeration plant it must be possible to carry out its hydraulic testing (before putting it into operation and periodically as necessary) with an excess pressure of 0.2 MPa. The vapor cooler is tested at an overpressure of 0.6 MPa.

Buy a deaerator
To purchase a deaerator, please contact the contacts listed at the top of the page.

Heating boilers are most often made of steel. The water passing through them contains oxygen and carbon dioxide. Both of these elements have an impact on metal constructions boiler has an extremely negative impact. Constant contact of steel with these gases inevitably leads to rusting. In order to correct the situation and extend the service life of the equipment, a special installation is turned on in boiler rooms - a deaerator. What it is? We'll talk about this later in the article.

Definition

A deaerator is a special equipment designed to remove oxygen from the coolant. heating systems by heating the latter with steam. Thus, in addition to the cleaning function, devices of this type also perform a thermal function. The same deaeration installation can be used to heat and purify both feed and makeup water.

Design Features

The relative simplicity of the design is what distinguishes the deaerator. We found out what it is. Now let's see how this equipment works. It is a boiler tank deaerator (BDA) with a vertical column (VCA) mounted on it, mounted on supports. Additional element Equipment of this type is equipped with a hydraulic system that protects it from excess pressure. The column is welded to the tank without a flange - directly.

On horizontal tank The deaerator has inlet and outlet pipes installed to connect the media supply and outlet lines. There are drains installed at the bottom. Another design element is a collection tank designed to collect degassed water. It is located under the bottom of the BDA.

Equipment such as a deaerator, the diagram of which is presented below, usually consists of two water seals. One of them protects the device from any excess of permissible pressure, and the second - from dangerous ones. The design of the deaerator hydraulic system also includes an expansion tank. The vapors from the deaerator enter a special cooler, which has the form of a horizontal cylinder.

Column design

The column is a cylindrical shell with an elliptical bottom. Like the tank, it has pipes for supplying and discharging the medium. Inside the column there are special plates with holes through which water passes. This design allows you to significantly increase the contact area between the medium and steam, and therefore produce heating at maximum speed.

Types of equipment

In modern boiler rooms a water deaerator can be installed:

vacuum;

atmospheric.

In the first type of deaerators, gases are removed from water in a vacuum. The design of such installations additionally includes a steam or water jet ejector. The last type of units is most often used in systems with medium or low power boilers. Instead of ejectors, special pumps can be used to create a vacuum. Some disadvantages of such equipment as vacuum deaerator, is that steam must be removed from it forcibly, while it comes out naturally from the atmosphere - under pressure.

In addition to the two types of deaerators discussed, high-pressure devices can be installed in boiler rooms. They operate at 0.6-0.8 MPa. Sometimes the thermal circuit of boiler houses also includes low-pressure equipment.

Scope of use

Where can a deaerator be used? What it is, you now know. Since such a device is intended for degassing working environment, it is mainly used where there is heating equipment made of steel.

Most often, deaerators are used in heating and hot water systems. Boiler houses with hot water boilers are usually equipped with vacuum-type installations. Atmospheric deaerators can also be used in such schemes. Low and high pressure units are used mostly in systems that operate thanks to the operation of a steam boiler. The first type (at 0.025-0.2 MPa) is installed in not very powerful systems designed for a small number of consumers. used in thermal circuits with boilers supplying large amounts of steam.

Disc deaerator: operating principle

The gas purification scheme in deaerators is implemented in two stages: jet (in a column) and bubbling (in a tank). In addition, a flooded bubbler device is included in the system. Water is fed into a column where it is treated with steam. Then it flows into the tank, is kept in it and is discharged back into the system. Steam is initially supplied to the BDA. After ventilation of the internal volume, it enters the column. Passing through the holes of the bubble plate, the steam heats the water to saturation temperature.

All gases are removed from the water using the jet method. At the same time, steam condensation occurs. Its residues are mixed with the gas released from the medium and discharged into the cooler. The condensate from the steam is drained into a drainage container. As the water settles in the tank, residual small gas bubbles come out of it. Water is discharged into a holding tank. Sometimes a horizontal container is used only for settling. In such installations, both stages of degassing are placed in a column.

Deaeration of make-up water

The coolant in the heating system circulates continuously. But its volume gradually decreases over time as a result of leaks. Therefore, make-up water is supplied to the heating system. Like the main one, it must undergo a deaeration process. Initially, the water enters the heater and then passes through filters chemical cleaning. Further, like the nutrient, it enters the deaerator column. The freed fluid flows to the latter and directs it to the suction manifold or storage tank.

Chemical deaeration

Thus, the answer to the question of what a boiler room deaerator is is simple. This is equipment designed to boil water with hot steam to remove oxygen. However, sometimes gases from the coolant in such installations are not completely removed. In this case, for additional purification, various kinds of reagents designed to bind oxygen can be added to the boiler water. This could be, for example, B in this case For high-quality deaeration of water, it needs to be heated. Otherwise, chemical reactions will occur too slowly. Also, various types of catalysts can be used to speed up the oxygen binding process. Sometimes water is deaerated by passing ordinary metal shavings through a layer. The latter in this case quickly oxidize.

Installation features

The deaerator device is not too complicated. However, its installation must be carried out in strict compliance with all required technologies. When installing such equipment, they are guided primarily by the drawings and boiler room design supplied by the manufacturer. Before installation begins, the installation is inspected and re-opened. Detected defects are eliminated. The installation procedure itself includes the following steps:

the tank is mounted on the foundation;

a drainage neck is welded to it;

the lower part of the column is cut to the outer diameter;

the column is installed on the tank (in this case, the plates fixed inside it must be positioned strictly horizontally);

the column is welded to the tank;

a vapor cooler and a water seal are installed;

the mains are connected in accordance with the drawings;

shut-off and control valves are installed;

are carried out hydraulic tests equipment.

Spray installations

The designs discussed above are called disc-shaped. There are also spray deaerators. Devices of this type are used less frequently and are also horizontal storage tank large capacity. The absence of a column is what distinguishes this deaerator. Its operating principle is also slightly different. Steam in such installations comes from below - from a comb located horizontally in the tank. The container itself is divided into a heating and deaeration zone. The boiler feed water enters the first compartment from the sprayer located on top. Here it is heated to the boiling point and enters the deaeration zone, where oxygen is removed from it by steam.

So, that's all that can be said about such a device as a deaerator. We hope you understand what this is, since we have given a fairly detailed answer to this question. This is the name of an installation that ensures long-term operation of hot water and steam boilers. The choice of type and installation methods of this equipment is carried out in accordance with technical characteristics heating equipment and boiler room design.

Deaerator- technical device, which implements the process of deaeration of some liquid (usually water), that is, its purification from unwanted gas impurities present in it (oxygen and carbon dioxide). When dissolved in water, these gases cause corrosion of feed pipes and boiler heating surfaces, resulting in equipment failure. At steam turbine stations, thermal deaeration of water is used.

The operating principle of thermal deaerators is based on the fact that the absolute pressure above a liquid is the sum of the partial pressures of gases and steam.

If we increase the partial pressure of steam so that while simultaneously removing vapor (this is a mixture of gases released from water and a small amount of steam that must be evacuated from the deaerator), then as a result we obtain the total partial pressure of gases. Then, according to Henry’s law (the equilibrium mass concentration of gases in a solution is proportional to the partial pressure in the gaseous medium above the solution), i.e. there are no dissolved gases. An increase in the partial pressure of steam, in turn, can be achieved by increasing the water temperature to the saturation temperature at a given pressure at .

Classification of thermal deaerators.

Intended use: steam boiler feedwater deaerators; additional water and return condensate from external consumers; make-up water of the heating network.

By heating steam pressure: high pressure (0.6-0.8 MPa)( D); atmospheric (0.12 MPa)( YES); vacuum (7.5-50 kPa)( Far East).

According to the method of heating deaerated water: mixing type (with mixing heating steam with heated water); deaerators of superheated water with external preheating of water with selected steam.

By design (according to the principle of formation of the interphase surface): with a contact surface formed in a turbulent mode (slim-bubble, film type with a disordered nozzle, jet disc type); with a fixed phase contact surface (film type with an ordered packing).

Schematic diagram deaeration installation.

Rice. Atmospheric deaerator mixing type: 1 - tank (battery), 2 - release of feed water from the tank, 3 - water indicator glass, 4 - pressure gauge, 5, 6 and 12 - plates, 7 - draining water into the drainage tank, 8 - automatic regulator supply of Chemically purified water, 9 - steam cooler, 10 - steam release to the atmosphere, 11 and 15 - pipes, 13 - deaerator column, 14 - steam distributor, 16 - water inlet into the hydraulic seal, 17 - hydraulic seal, 18 - release of excess water from a hydraulic valve

The deaerator consists of a tank 1 and a column 13, inside of which a number of distribution plates 5, 6 and 12 are installed. Feed water (condensate) from the pumps enters the upper part of the deaerator onto the distribution plate 12; through another pipeline through regulator 8, chemically purified water is supplied to plate 12 as an additive; From the plate, feed water is distributed in separate and uniform streams over the entire circumference of the deaerator column and flows down sequentially through a series of intermediate plates 5 and 6 located one below the other with small holes. Steam for heating water is introduced into the deaerator through pipe 15 and steam distributor 14 from below under the water curtain formed when water flows from plate to plate, and, diverging in all directions, rises up towards feed water, heating it up. At this temperature, air is released from the water and, together with the remainder of the uncondensed steam, goes through the lead pipe 11, located in the upper part of the deaeration head, directly into the atmosphere or steam cooler 9. The oxygen-free and heated water is poured into the collection tank 1, located under the deaerator column , from where it is used to power boilers. To avoid a significant increase in pressure in the deaerator, two hydraulic valves are installed on it, as well as a hydraulic valve 17 in case of vacuum formation in it. If the pressure is exceeded, the deaerator may explode, and if there is a vacuum Atmosphere pressure may crush it. The deaerator is equipped with a water indicator glass 3 with three taps - steam, water and purge, a water level regulator in the tank, a pressure regulator and the necessary measuring equipment. For reliable operation feed pumps the deaerator is installed at a height of at least 7 m above the pump.