The Rotating Membrane Deaerator is a substitute product for the Spray Filled Deaerator, producing a new type of thermal deaerator. The principle of the Rotating Membrane Deaerator involves replenishing water through a film-forming tube, which is sprayed out in a spiral pattern at a specific angle to exchange heat with the steam, thus removing oxygen. It heats the water to the saturation temperature at the corresponding deaerator working pressure, eliminating dissolved oxygen and other gases in the feedwater, and preventing or reducing corrosion in the boiler feed water pipes, economizers, and other auxiliary equipment.
The deaerator equipment is mainly composed of two major components: the deaerator tower head and the deaerator water tank, as well as connecting pipes and external accessories. The main component, the deaerator (deaerator tower head), consists of the outer shell, steam-water separator, new-type rotating film separator (film tube), sprinkling grating, heat storage filling liquid-gas mesh, and other parts. Below, we will focus on the structural principle of the deaerator tower head.
The shell is welded from a cylinder body and a stamped elliptical end cap. Medium and small low-pressure deaerators are equipped with a pair of flanges for connecting the upper and lower parts, for assembly and maintenance purposes. High-pressure deaerators are fitted with access manholes for maintenance.
The Soda Separator: This device replaces the original old-style deaerator with a grass hat cone structural design, eliminating the phenomenon of steam exhaust carrying water.
3. Membrane Rotator Unit: Comprising a water chamber, steam chamber, membrane tube, condensate outlet, make-up water inlet, and primary steam inlet. The condensate, chemical make-up water, and water exiting the membrane rotator spiral out at a certain angle, forming a water film skirt. This skirt then undergoes heat exchange with the heating steam introduced through the primary steam inlet, resulting in deaeration. The feedwater is heated through contact with the ascending secondary heating steam, reaching a temperature close to the deaerator's operating pressure's saturation point, which is 2-3°C below the saturation temperature, and undergoes rough deaeration. Generally, this membrane rotator section can remove approximately 90-95% of the oxygen content in the feedwater.
4. Watering Grating: Composed of several layers of angular steel arranged in an interlaced pattern, the water supply that has undergone rough degassing in the spiral membrane section is here distributed for a second time, falling uniformly in a shower-like manner onto the liquid-gas mesh below.
5. Heat Storage Filler Material Liquid-Vapor Network: Composed of alternating flat steel strips and a cylindrical body, filled with a certain height of specially designed stainless steel wire mesh. Here, water is in full contact with the secondary steam, heated to saturation temperature, and deeply deoxygenated. The low-pressure atmospheric deoxygenator is below 10ug/L, and the high-pressure deoxygenator is below 5ug/L (the national standards are 15ug/L and 7ug/L, respectively).
6. Deoxygenated water from the tank is collected in the lower container of the deaerator, which is the tank itself. The deaeration tank is equipped with a new scientifically designed powerful heat exchange and reboiling unit. This unit features powerful heat exchange, rapid temperature increase, deeper deoxygenation, reduced tank vibration, and lower accent, thereby enhancing the equipment's lifespan and ensuring the safety and reliability of its operation.
Deaerators are one of the key equipment in boiler and heating systems. If the deaeration capacity of the deaerator is poor, it will cause severe corrosion to the boiler feed water pipes, economizers, and other auxiliary equipment, leading to economic losses that could be several or even hundreds of times the cost of the deaerator itself. Consequently, the National Electric Power Department has established certain standards for the oxygen content of deaerators, specifying that the oxygen content in the feed water of atmospheric deaerators should be less than 15 μg/L, and for pressure deaerators, less than 7 μg/L.
