Rotating membrane deaerator

The rotary film deaerator is a new type of thermal deaerator that can meet the requirements of different types of boiler feedwater, as well as achieve the goals of energy conservation and environmental protection, thereby reducing the large amount of metal loss caused by oxygen corrosion and the waste of manpower and material resources caused by equipment replacement, making it have good prospects for promotion.

The rotary film deaerator uses a new type of spray device, and its special design also makes the manufacturing process difficult. Through multiple process experiments, we have developed a processing method for the membrane nozzle. We have adopted a new manufacturing process and adopted a reasonable assembly plan for the nozzle. We have also explored the assembly plan for the inlet device and strictly adhered to welding specifications, ensuring the spiral arrangement of the nozzle holes. After the product is operated, the thickness of the effluent film is uniform and consistent, achieving deoxygenation and ensuring the design requirements and performance of the deaerator.

Advantages of rotary membrane deaerator:

1. High deoxygenation efficiency and qualified water supply rate. (High pressure 5 цɡ/L, low pressure 10 цɡ/L.). Fully meet the standards issued by the Ministry of Electric Power)

2. Stable operation without vibration. When the load suddenly changes by 25%, the makeup water suddenly changes by 10%, and the water temperature drops, the deaerator still does not vibrate or vaporize. Easy to control and manage

3. In addition to its good adaptability and low requirements for water quality and temperature, it can also operate at an output exceeding 50%, especially for heating units and deaerators operating under sliding pressure, demonstrating its superior performance.

4. Optimized the equipment and reduced heat consumption. The exhaust steam volume is less than 0.1% of the inlet water volume, which consumes one-third less energy than other types of thermal deaerators with the same output.

With the popularization and development of softened water treatment technology, the issue of deoxygenation in boilers and heating systems has become increasingly important. The serious losses caused to boilers and heat exchange equipment by oxygen corrosion every year have attracted increasing attention. For this reason, relevant departments have made multiple revisions to the boiler feedwater standards. GB1576-2001 "Water Quality Standards for Industrial Boilers" stipulates that for steam boilers, deoxygenation should be carried out when the rated evaporation capacity is greater than or equal to 6t/h. If local corrosion is found when it is less than 6t/h, deoxygenation measures should be taken. For hot water boilers, deoxygenation should be carried out when the rated thermal power of the boiler is greater than or equal to 4.2MW, and deoxygenation should be carried out as much as possible for boilers with a rated thermal power less than 4.2MW. There are many traditional deoxygenation methods, such as atmospheric thermal deoxygenation, vacuum deoxygenation, desorption deoxygenation, steel chip deoxygenation, oxidation-reduction resin deoxygenation, and sodium sulfite chemical deoxygenation, but they all have many problems, especially limited in their application in hot water boilers. Therefore, although strict water quality standards have been established by relevant departments, the lack of convenient and effective deoxygenation equipment has hindered the effective implementation of these regulations

Rotary membrane deaerator

Deaerator is one of the key equipment in boilers and heating systems. If the deoxygenation capacity of the deaerator is poor, it will cause serious losses to the boiler feedwater pipeline, economizer, and other ancillary equipment due to corrosion, and the economic losses caused will be tens or hundreds of times the cost of the deaerator. Therefore, the Ministry of Electric Power has proposed a departmental standard for the oxygen content of the deaerator. The oxygen content of the deaerator, namely the atmospheric deaerator feedwater, should be less than 15 цɡ/L, and the oxygen content of the pressure deaerator feedwater should be less than 7 цɡ/L.

Deoxygenation law, Gallusak's law

When the pressure remains constant, for every 1 ℃ increase in temperature of a certain mass of gas, the increase in volume is equal to 1/273 of its volume at 0 ℃; Or when the pressure remains constant, the volume of a certain mass of gas is directly proportional to its thermodynamic temperature. Discovered by French scientist Guy Lussac in experiments. Suitable for ideal gases, it is also approximately applicable to real gases under high temperature and low pressure.

Henry's law states that at a certain temperature, when the total pressure of the gas phase is not high, for dilute solutions, the concentration of solutes in the solution is proportional to their partial pressure in the gas phase. Dalton's partial pressure law states that when the temperature and volume are constant, the total pressure of a mixed gas is equal to the sum of the partial pressures of the component gases, and the partial pressures of each component gas are equal to the pressure exhibited by the gas when it occupies the total volume alone.

Structural principle of deaerator

The deoxygenation equipment mainly consists of two major parts: the deoxygenation tower head and the deoxygenation water tank, as well as connecting pipes and external components. The main component of the deoxygenation device (deoxygenation tower head) is composed of an outer shell, a new type of membrane separator (membrane tube), a water spray grate, and a thermal storage packing liquid vapor network Below, we will focus on introducing the structural principle of the deoxygenation tower head

1. Shell: It is made by welding a cylindrical body and a stamped elliptical head The medium and low pressure deaerators are equipped with a pair of flanges connecting the upper and lower parts for assembly and maintenance, while the high pressure deaerator is equipped with a manhole for maintenance

2. Membrane deaerator group: composed of water chamber, steam chamber, membrane tube, condensate connection, make-up water connection, and primary steam inlet connection Condensed water, chemical makeup water, and water are sprayed out in a spiral shape at a certain angle through a membrane separator, forming a water film skirt, and exchanging heat with the heating steam introduced through the primary heating steam connection to form a primary deoxygenation. The feedwater is heated to a saturation temperature close to the working pressure of the deoxygenator, that is, 2-3 ℃ lower than the saturation temperature, and undergoes crude deoxygenation Generally, about 90-95% of the oxygen content in the feedwater can be removed through this membrane spinning section

3. Dripping grate: It is made up of several layers of staggered angular steel, and the water that has been roughly deoxygenated by the rotating membrane section is redistributed here, falling uniformly in a rain like manner onto the liquid vapor screen installed below it

4. Thermal storage filling liquid vapor network: It is composed of flat steel strips and a cylindrical body that are spaced apart from each other, and is equipped with a specially designed stainless steel wire mesh at a certain height. The feedwater is fully in contact with the secondary steam here, heated to saturation temperature and deeply deoxygenated. The low-pressure atmospheric deaerator is below 10ug/L, and the high-pressure deaerator is below 5ug/L (the departmental standards are 15ug/L and 7ug/L, respectively)

5. The feed water for removing peroxide from the water tank is collected in the lower container of the deaerator, which is the water tank. The deaerator tank is equipped with a newly scientifically designed heat exchange and reboiling device. This device has the advantages of heat exchange, rapid increase in water temperature, deeper deaeration, reduced tank vibration, and reduced noise, which improves the service life of the equipment. The deaerator ensures the reliability of equipment operation