Regarding deaerators

Deoxygenation includes thermal deoxygenation and chemical deoxygenation. Boilers that generate steam generally use thermal deoxygenation, employing the steam produced by the same boiler for deoxygenation. Thermal deoxygenation is based on the principle of Henry’s law

Most factories use deaerators for this purpose; it is a cost-effective approach. It is also simple and easy to operate, as steam is available in every factory. Moreover, the condensate water from the equipment can also be fed into the deaerator! ! This saves some steam and also recovers the condensed water! !

Deaerators come in thermal deaeration and chemical deaeration types. Thermal deaeration may not be the most cost-effective in terms of operation and maintenance costs, but it is indeed the easiest to operate.

The deaerator is one of the key components in boilers and heating systems. If its deoxygenation capacity is insufficient, it can cause severe corrosion to the boiler feedwater pipes, economizers, and other associated equipment, resulting in economic losses that can be dozens or even hundreds of times higher than the cost of the deaerator itself. For this reason, the Ministry of Electric Power has established standard requirements regarding the oxygen content in deaered water: the oxygen content in the feedwater for atmospheric deaerators should be less than 15 mg/L, while for pressure deaerators it should be less than 7 mg/L. 　　Law of dégassing, Gay-Lussac’s law: At constant pressure, for a given mass of gas, an increase in temperature of 1°C results in a volume increase equal to 1/273 of its volume at 0°C ； Or, at constant pressure, the volume of a given mass of gas is proportional to its thermodynamic temperature. It was named after an experiment conducted by the French scientist Gay-Lussac. It applies to ideal gases, and is also approximately applicable to real gases at high temperatures and low pressures. 　　Henry’s law states that, at a constant temperature and when the total pressure of the gas phase is not high, for dilute solutions, the concentration of the solute in the solution is proportional to its partial pressure in the gas phase. Dalton’s law of partial pressures states that, at constant temperature and volume, the total pressure of a mixed gas equals the sum of the partial pressures of its constituent gases; each component gas’s partial pressure corresponds to the pressure it would exert if it occupied the entire volume by itself. 　　Structure and Principle of the Deaerator The deaeration equipment mainly consists of two main components: the deaeration tower head and the deaeration water tank, along with connecting pipes and other accessories. The key component, namely the deaerator (deaeration tower head), is made up of an outer shell, a new type of spiral film generator (film-forming tube), a water spraying grid, and a heat storage filler along with a liquid-vapor network. Below, we will focus on explaining the structure and principle of the deaeration tower head. 1. Outer Shell: This is formed by welding a cylindrical body with an elliptical head that has been stamped. Medium and low-pressure deaerators are equipped with a pair of flanges to connect the upper and lower parts, facilitating assembly and maintenance; high-pressure deaerators have manholes for maintenance purposes. 2. Spiral Film Generator Set: This set consists of a water chamber, a vapor chamber, spiral film tubes, condensate water connections, make-up water connections, and primary steam inlet connections. Condensate water and chemical make-up water are sprayed in a spiral pattern at a certain angle through these tubes, forming a water film skirt. This film skirt exchanges heat with the heating steam introduced through the primary steam inlet connections, thereby achieving initial deaeration. The feed water then comes into contact with the rising secondary heating steam via the water spraying grid, being heated to a temperature close to the saturation temperature under the deaerator’s operating pressure – typically 2-3°C below saturation temperature – allowing for rough deaeration. Generally, this spiral film section can remove around 90-95% of the oxygen content in the feed water. 3. Water Spraying Grid: This is composed of several layers of angular steel bars arranged in an interlaced pattern. Here, the feed water that has undergone rough deaeration through the spiral film section is distributed evenly, falling like rain onto the liquid-vapor network located beneath it. 4. Heat Storage Filler Liquid-Vapor Network: This consists of spaced flat steel strips and a cylindrical structure filled with a specially designed stainless steel mesh of a certain height. In this area, the feed water comes into full contact with the secondary steam, being heated to the saturation temperature and thus undergoing further deaeration. For low-pressure atmospheric deaerators, the oxygen level is reduced to below 10 ug/L, while for high-pressure deaerators, it is reduced to below 5 ug/L (the standard values set by regulations are 15 ug/L and 7 ug/L respectively). 5. Water Tank: The deoxygenated feed water is collected in the container located at the bottom of the deaerator, namely the water tank. This tank is equipped with a scientifically designed high-efficiency heat exchange and reboiling device. This device enables efficient heat exchange, rapid increase in water temperature, further deaeration, reduction in tank vibration, and lowering of noise levels. All these advantages enhance the equipment’s lifespan and ensure its safe and reliable operation.

I still don’t quite understand it; it seems a bit abstract!

There are two methods for deoxidizing boilers: thermal deoxidization and chemical deoxidization. Thermal deoxidization involves using steam to pass through the deoxidizer, while chemical deoxidization, also known as chemical treatment, entails using a dosing pump to add deoxidizers to the boiler’s water supply system. Our approach is to use chemical deoxidization when there is a shortage of steam in the system, and thermal deoxidization when there is an abundance of steam

Excuse me, the guest upstairs: since I haven’t used it before, what chemicals are generally used for chemical deoxygenation? Thank you

What is the typical operating pressure for pressure deaeration?

Deoxygenation includes thermal deoxygenation and chemical deoxygenation; boilers generally use thermal deoxygenation, employing steam generated on-site for this purpose, as it is a convenient and economical method.

Currently, thermal deoxidation is more commonly used, while chemical deoxidation is less so. Thermal deaeration is simple to operate and has relatively low operating costs.

Thermal deoxidation, chemical deoxidation, scrap metal deoxidation, desorption deoxidation. Heat power plants now use thermal deaerators. Oxygen removal using steel scrap is generally not used in small industrial devices, and is virtually absent in thermal power plants. Chemical deoxidation is generally used as a supplement to thermal deoxidation, and it is not a device or container. The theoretical principle is Henry’s law of Dalton, which was explained by the colleague on the 5th floor. However, the deaerator discussed here is only the rotary film type deaerator (which is also the type most commonly used in power plants today). In addition, there are also drip tray types, spray types, packed bed types, and so on. However, these structures are now also being converted into rotary diaphragm types.

Common methods include thermal deoxidation and chemical deoxidation; thermal deoxidation is generally used as it can make use of the steam generated by the boiler, is easy to operate, and requires less investment

We have thermal deoxidation and chemical deoxidation; generally, using them together seems to yield better results

Deoxygenation methods generally include thermal deoxygenation, adsorption deoxygenation, and chemical deoxygenation; the appropriate method must be chosen depending on the specific circumstances and the capacity of the boiler. Each has its advantages and disadvantages. **It is stipulated that deaeration equipment must be installed in boilers with a capacity of 6 T/H or more; for smaller boilers, it is sufficient to control the water quality properly. In larger boilers, thermal deaeration is generally used, with a deaeration head pressure of 0.2–0.3 MPA being sufficient

Deaerators are subject to strict standards, and the type most commonly used nowadays is the spiral-wall deaerator.

Oxygen in demineralized water can be removed at a pressure of around 0.01 Mpa and a temperature of 104 degrees

Thermal deaerators are generally divided into two types: those with an operating pressure of less than 0.1 Mpa are known as atmospheric deaerators, or low-pressure deaerators; they usually operate at a pressure of 0.02 Mpa and a temperature of 104°C. Another type is the one where the operating pressure is 0.1 Mpa or higher; it is known as a pressure-type deaerator, also referred to as a high-pressure deaerator. It generally operates at a pressure of 0.488 Mpa and at a temperature of 158°C.