Rotary Film Type Deaerator
This deaerator has strong adaptability, can operate stably under the conditions of low temperature water or overload, with small exhaust volume, high deaeration efficiency, stable dissolved oxygen, reliable operation and convenient maintenance.
In order to prevent corrosion of thermal equipment and pipes, dissolved oxygen and other gases dissolved in boiler feed water must be removed, to ensure the safe operation and long service life of thermal equipment.
Rotary film type deaerator is a kind of hybrid heater. The main function is to remove the non condensable gases such as oxygen and carbon dioxide in the softened water, and then the softened water is heated to the saturation temperature under the operating pressure of the deaerator. The heating steam source is generally the extraction steam at the pressure side of the steam turbine and residual steam, high temperature drainage of other sides in the power station, which improves the thermal economy of the system. The saturated water meeting standard oxygen content is stored in the deaerator water tank, which meet the demands of the boiler anytime to ensure the safe operation of the boiler. The rotary film type deaerator has two sections, the rotary film deaeration section and the deep deaeration section. The boiler feed water from the LP feedwater heater firstly enters the water chamber of the deaerator. Due to a certain pressure difference, the water is injected into the film nozzle from the inlet hole. When the water is injected into the inner wall of the nozzle, it immediately swirls down along the inner wall of the nozzle, forming a hollow rotating water film skirt at the outlet end of the nozzle. The inner and outer sides of the water film skirt are in full contact with the heating steam. At this moment, the water is heated to the saturation temperature, and most of the non condensing gas is rapidly separated out. The initial deaeration rate of the rotating film deaeration section is about 90%. The water after initial deaeration is evenly distributed to the packing layer through the water spray tray. The water in the packing layer is separated into water film again, which greatly reduces the surface tension of the water, and has enough residence time to contact with the superheated steam. The residual oxygen in the water is further separated out in the packing layer, so that the oxygen content of the deaerated water reaches the standard requirements , oxygen content <15μg/L, high pressure oxygen content <7μg/L.So this section is called the deep deaeration section. All the non condensable gas removed in the rotary film deaeration section and deep deaeration section will rise to the exhaust pipe at the top of deaerator and discharge to the atmosphere. The main types of rotary film deaerator are atmospheric (low pressure) deaerator and pressure (high pressure and medium pressure) deaerator. The operation modes have constant pressure and sliding pressure. Connection types between deaerator and water storage tank are vertical and horizontal.