The principle of thermal deoxygenation, what is the basic principle of thermal deoxygenation

The principle of thermal deoxygenation is based on Henry's Law and Dalton's Law. Henry's law states that when the liquid and gas are in equilibrium, corresponding to a certain temperature, the amount of gas dissolved per unit volume of water Dalton's law states that the full pressure of the gas mixture is equal to the sum of the partial pressures of the constituent gases and is proportional to the partial pressure of the gas on the water surface.

According to Henry's law, the thermal deaerator (high-efficiency rotary membrane deaerator) adopts the components composed of three different functions of the rotary membrane in the structure, establishes the mass transfer method of the vapor section, and improves the rotary membrane technology.

The heat transfer and mass transfer methods of the rotary membrane deaerator are different from the existing liquid column type, atomization type and bubble boiling type, which is a heat transfer and mass transfer mode that condenses the three heat transfer and mass transfer modes of jet, rotating membrane and hanging bubble boiling, and has high efficiency.

The natural falling film is changed to a strong falling film, which increases the renewal degree of the liquid film, so that the liquid film rotates strongly along the pipe wall to absorb a large amount of steam, and enhances the heat and mass transfer functions; The opposite bubble boiling is changed to a suspended bubble boiling, which increases the flood point (splash) when the steam flow rate in the layer is high, and will maintain the vapor (gas) gas channel; The three independent heat and mass transfer methods are reduced into one and completed in one unit.

According to Henry's law: the concentration of a certain gas dissolved in water is proportional to the partial pressure of the gas on the surface of the gas and liquid, if the water is heated to boiling, the surface of the gas and liquid is almost 100% water vapor, and at the same time, the original dissolved in the water and other gases such as oxygen will escape from the water, as long as the water is divided into small enough water droplets and the gas on the liquid surface is pumped out in time, the oxygen and other dissolved gases in the water can be removed, and the escaped gas will not be re-dissolved in the water.

The deaerator is to heat the water (with steam) to the boiling point at this temperature, and continuously extract the escaping gases to achieve the purpose of oxygen removal (in fact, to remove all dissolved gases).

To achieve adequate oxygen removal, three conditions need to be met:

1。heat the water to the boiling point at that pressure;

2。Divide the water into small enough droplets;

3。Expel the escaping gases in a timely manner.

The steam heats the boiler feed water to the saturation temperature under the pressure of the atmospheric thermal deaerator (, at this time, the steam pressure on the surface of the water is close to the full pressure of the water surface, and the partial pressure of various gases dissolved in the water is close to zero.

The atmosphere is mainly composed of nitrogen, oxygen, carbon dioxide, water vapor and a small amount of other gases, and atmospheric pressure is the sum of the partial pressures of the various gases that make up the atmosphere.

According to the law of gas dissolution (Henry's Law): the solubility of any gas in water is directly proportional to the partial pressure of that gas at the gas-water interface, regardless of atmospheric pressure. In other words, the dissolved oxygen content in the water is only related to the partial pressure of oxygen in the atmosphere, and the smaller the partial pressure of oxygen, the dissolved oxygen content in the water also tends to be close to zero.

When water is heated to boiling in the atmosphere, the saturated vapor pressure of the water is equal to the atmospheric pressure at the air-water interface, and the partial pressure of oxygen is equal to zero. At this time, the solubility of oxygen Zheng Weiwei in the water is removed from the water due to a sharp decrease, which is the principle of thermal deoxygenation.

<> thermal deoxygenation to achieve a good deoxygenation effect, the following basic conditions must be met:

1. The water must be heated to the saturation temperature at the corresponding pressure;

2. Make the analysis process of the gas source sufficient;

3. Ensure that water and steam have sufficient contact time and contact area.

The principle of thermal deoxygenation, the use of steam to heat the boiler feed water to the saturation temperature of the atmospheric thermal deaerator pressure, then the water surface steam pressure is close to the full pressure of the water surface, the partial fracturing force of various gases dissolved in the water is close to zero, the feed water does not have the ability to dissolve the gas, and the gas dissolved in the water will precipitate, so as to achieve the purpose of removing oxygen and protecting the thermal equipment and pipelines.

<> thermal deoxygenation to achieve a good deoxygenation effect, the following basic conditions must be met:

1. The water must be heated to the saturation temperature at the corresponding pressure;

2. Make the gas analysis process sufficient;

3. Ensure that water and steam have sufficient contact time and contact area.

The principle of thermal deoxygenation, the use of steam to heat the boiler feed water to the saturation temperature under the pressure of the atmospheric thermal deaerator, then the steam pressure on the surface of the water is close to the full pressure of the water surface, the partial pressure of various gases dissolved in the water is close to zero, the feed water does not have the ability to dissolve the gas, and the gas dissolved in the water will precipitate, so as to achieve the purpose of removing oxygen and protecting the thermal equipment and pipelines.

In order to achieve a good deoxygenation effect, the following basic conditions must be met:

1. The water must be heated to the saturation temperature at the corresponding pressure;

2. Make the gas analysis process sufficient;

3. Ensure that water and steam have sufficient contact time and contact area.

The principle of thermal deoxygenation, the use of steam to heat the boiler feed water to the saturation temperature under the pressure of the atmospheric thermal deaerator, at this time the water surface steam pressure is close to the full pressure of the water surface, the partial pressure of various gases dissolved in the water is close to zero, the feed water does not have the ability to dissolve the gas, and the gas dissolved in the water will be precipitated, so as to achieve the purpose of removing oxygen and protecting the thermal equipment and pipelines.

Thermal deoxygenation is carried out according to the law of gas dissolution (Henry's law), which is proportional to the solubility of a gas in water and its partial pressure.

In the process of heating water, as the temperature increases, the partial pressure of steam becomes higher and higher at the steam-water interface, and the partial pressure of oxygen and other gases becomes lower and lower. When water is heated to its boiling point, the pressure of water vapor rises to the same level as the outside pressure, and the partial pressure of oxygen and other gases drops to zero, so that the dissolved oxygen in the water escapes completely.

From Henry's law, it can be seen that in equilibrium, the amount of gas dissolved per unit volume of water is proportional to the partial pressure of the gas on the water surface, and thermal deoxygenation is the application of Henry's law. In the heating process, the partial pressure of water vapor on the water surface gradually increases, and the partial pressure of other gases gradually decreases, and the vapor in the water is continuously separated and precipitated.

The principle of thermal deoxygenation, the use of steam to heat the boiler feed water to the saturation temperature under the pressure of the atmospheric thermal deaerator, then the steam pressure on the surface of the water is close to the full pressure of the water surface, the partial pressure of various gases dissolved in the water is close to zero, the feed water does not have the ability to dissolve the gas, and the gas dissolved in the water will precipitate, so as to achieve the purpose of removing oxygen and protecting the thermal equipment and pipelines. Basic principles of thermal deoxygenation:

In a container, the amount of gas dissolved in the water is proportional to the partial pressure of the gas on the water surface. According to the dissolution characteristics of the gas in the water, if you want to remove any kind of gas in the water, you only need to remove the gas present on the water surface, so if you want to remove all kinds of gases in the water, it is best to have only water vapor and no other gases on the water surface. Thermal deoxygenation is to heat the water to the boiling point, the solubility of oxygen decreases and escapes, and then the oxygen generated on the water surface is eliminated to fill it with steam, so that the oxygen in the water continues to escape, and the oxygen content of the feed water meets the requirements of the feed water quality standard.

In order to achieve a good deoxygenation effect, the following basic conditions must be met:

1. The water must be heated to the saturation temperature at the corresponding pressure;

2. Make the gas analysis process sufficient;

3) Ensure that the water and steam socks are dismantled with sufficient contact time and contact area.