What do deaerators do?
Deaerators are mechanical devices that remove dissolved gases from boiler feedwater. Deaeration protects the steam system from the effects of corrosive gases. It accomplishes this by reducing the concentration of dissolved oxygen and carbon dioxide to a level where corrosion is minimized.
What is the meaning of deaerator?
verb (used with object), de·aer·at·ed, de·aer·at·ing. to remove air or gas from. to remove bubbles from (a liquid, as boiler feedwater), as by mechanical agitation in a vacuum or by heating at atmospheric pressure.
How is water Deaerated?
The simplest is boiling the water, as oxygen has very low solubility in hot water. “Scrubbing” of the water with oxygen-free CO2 or nitrogen is another method, and finally applying a vacuum to water trickling over a large surface (often in a hollow tube filled with small “fillers”) can also be applied.
Why deaerator is kept at height?
Why are deaerators placed at height? Deaerators are placed at height to provide sufficient NPSHa (Net Positive Suction Head available) to the boiler feedwater pumps – the boiler feed pumps are typically situated low in the ship for the same reason.
What is vacuum deaerator?
Vacuum Deaerator or degasifier are designed to effectively remove select non-condensable gases from the liquid stream. A vacuum is pulled on a stream of water, and the vacuum draws the dissolved gas out of solution, removing it from water.
What is a spray type deaerator?
The Spray-Type Deaerator consists of a horizontal or vertical cylindrical vessel which serves as both the deaeration section and the boiler feedwater storage tank. The typical spray-type deaerator is a horizontal vessel which has a preheating section and a deaeration section.
What causes deaerator cracking?
Cracking in deaerator heaters and/or deaerator storage tanks is typically the result of mechanical fatigue or mechanical shock conditions. The mechanical fatigue is the result of cyclic stresses created by such operating conditions as full load rejection, temperature/pressure fluctuations, and water hammer.
How do you design a deaerator?
In a typical deaerator, this is accomplished by spraying the incoming water into a pressurized steam atmosphere, where it is heated to within a few degrees of the saturation temperature of the steam.
How much oxygen is present in steam?
This heats the water to within a few degrees of the temperature of the saturated steam. Because the solubility of oxygen in water is very low under these conditions, 97 to 98% of the oxygen in the incoming water is released to the steam and is purged from the system by venting.
Why deaerator is used at thermal power plant after condenser?
In thermal power plants, the deaerator is used mainly to. Remove air from condenser. Increase feed water temperature. Reduce steam pressure.
What is the use of condenser in thermal power plant?
The function of a condenser in thermal cycle is to maintain the exit pressure of the turbine lower than the atmosphere pressure. It appreciably increases the work done per kg of steam. i.e. some extra work is obtain from steam. This improves in efficiency of the plant.
What is ID fan in thermal power plant?
The Induced Draft (ID) fans and Forced Draft (FD) fans provide control for draft and forced air zoning of fuel burned furnaces of steam generation plant of a thermal power plant. Forced Draft (FD) fans are used for supplying the combustion air into the furnace of a boiler.