What Is a Deaerator?

Rotary film deaerator is a replacement product of spray-filled deaerator. It is a new type of thermal deaerator produced. The principle of rotary film deaerator is that the water is sprayed through the film tube in a spiral shape at a certain angle. Heat exchange with heating steam to remove oxygen, feed water to the saturation temperature under the corresponding deaerator working pressure, remove oxygen and other gases dissolved in the feed water, prevent and reduce the corrosion of boiler feed water pipes, economizers and other auxiliary equipment.

Deaerator

Rotary film deaerator is a replacement product of spray-filled deaerator. It is a new type of thermal deaerator produced. The principle of rotary film deaerator is that the water is sprayed through the film tube in a spiral shape at a certain angle. Heat exchange with heating steam to remove oxygen, feed water to the saturation temperature under the corresponding deaerator working pressure, remove oxygen and other gases dissolved in the feed water, prevent and reduce the corrosion of boiler feed water pipes, economizers and other auxiliary equipment.

Chinese name

Deaerator

Deoxidation law

Deaerator is one of the key equipment of boilers and heating systems. If the deaerator has a poor deaeration capacity, it will cause serious losses to the corrosion of boiler water supply pipes, economizers and other auxiliary equipment, and the economic loss caused will be Dozens or hundreds of times the cost of oxygen generators

The deaeration equipment is mainly composed of two parts: the deaeration tower head and the deaeration water tank, as well as the takeover and external parts. The main parts of the deaerator (deaerator tower head) are the shell, the steam-water separator, and the new type of membrane spinner. Pipe), water rafter, heat storage packing liquid vapor network and other components. The following will focus on the structure principle of the deaerator tower.

1. Housing: It is made by welding the cylinder body and stamped oval head. The middle and small low pressure deaerators are equipped with a pair

Condensate and make-up water first enter the water chamber of the inner spinner unit of the deaerator head, and it is sprayed obliquely from the small holes of the membrane tube to the inner holes under a certain water level differential pressure to form a jet. Because the inner holes are filled with rising heating steam A large amount of heated steam is drawn in by the water during the movement of the jet (experiment proves that the movement of the jet has a suction effect); a violent mixed heating effect is generated on a very short stroke, the water temperature is greatly increased, and the rotating Water along

Make sure that the deaerator starts the exhaust electric valve and the continuous exhaust bypass valve in the open position.

When the condensate system is flushed properly, open the deaerator flushing drain valve and flush the deaerator with water.

(3) After the water quality of the deaerator is qualified, reduce the water level to -900mm and close the deaerator flushing and draining door.

(2) Turn on the auxiliary steam of the deaerator, open the auxiliary steam to the front and rear isolation doors of the deaerator, and slowly open the auxiliary steam to the deaerator pressure regulating valve to control the deaerator feed water temperature rise rate not greater than 4.26 ° C / min during the heating process. Pay attention to the vibration of the deaerator. If the vibration is large, the heating speed should be slowed down.

During the heating process of the deaerator, continue to use the condensate pump to water the deaerator to the normal water level.

The principle of thermal deaeration is based on Henry's Law and Dalton's Law.

Henry's Law states that at a certain temperature, when a gas dissolved in water and a gas isolated from water are in a dynamic equilibrium state, the amount of dissolved gas per unit volume of water is proportional to the partial pressure of the gas on the water surface.

According to Henry's law, if the actual partial pressure of a gas on the water surface is less than the equilibrium pressure corresponding to the dissolved gas in the water, the gas will be separated from the water under the effect of the unbalanced pressure difference until it reaches a new equilibrium. If the gas can be completely removed from the water surface so that the actual partial pressure of the gas is zero, the gas can be completely removed from the water. This is the basic principle of thermal deaeration.

Dalton's law provides a way to reduce the partial pressure of the gas on the surface to zero. It states that the total pressure of the mixed gas is equal to the sum of the partial pressures of the constituent gases.

When the feed water is heated at a constant pressure, as the water evaporation process progresses, the amount of steam on the water surface continues to increase, the partial pressure of steam gradually increases, and the gas is eliminated in time. Accordingly, the partial pressures of various gases on the water surface continue to decrease. When the water is heated to the saturation temperature under the pressure of the deaerator, a large amount of water evaporates, and the partial pressure of water vapor will approach the full pressure on the water surface. As the gas is continuously discharged, the partial pressures of various gases on the water surface will tend to Near zero, the gas dissolved in the water will escape from the water and be removed. ^[1]

It can not only remove dissolved oxygen in boiler feed water, but also remove corrosive gases such as free CO ₂ , NH ₃ , H ₂ S in the water.

After deaeration, the salt content and other impurities will not increase.

The use of high-efficiency fillers has high oxygen removal efficiency, and the feed water can also be used at room temperature.

Under normal room temperature conditions, the oxygen content of the effluent can still meet the requirements.

classification

The deaeration equipment is mainly composed of two parts: the deaerator tower head and the deaerator water tank, and the takeover and external parts. The main components of the deaerator (deaerator tower head) are the shell, the steam-water separator, and the new membrane spinner Pipe), water rafter, heat storage filler liquid vapor network and other components

When the load is less than 20% of the rated load, the deaerator is switched from four-pump to auxiliary steam heating, maintaining a constant pressure operation of 0.147MPa.

When the unit stops running, decide whether to stop the deaerator water supply according to the specific situation.

(3) If the deaerator is out of service for more than two months, it should be protected by nitrogen filling, cut off all steam and water sources, drain the remaining water in the water tank, close the drain valve, and open the nitrogen filling main door and isolation door after full isolation to deaerator. The device was filled with nitrogen and maintained a certain pressure.