Working Principle and Types of Deaerator
In this post, we’ll learn about Working Principle and Types of Deaerator
What is Deaerators?
The removal of dissolved gasses from boiler feed water is an important method during a steam system. The presence of dissolved oxygen in feedwater causes speedy localized corrosion in boiler tubes.
The dissolved CO2 in water, leading to low pH levels and therefore the production of corrosive carbonic acid. Low pH levels in feed water cause severe acid attacks throughout the boiler system.
Read: Working Principle Of High-Velocity Oxy-Fuel Coating Process (HVOF)
By removing the dissolved gasses within the boiler feedwater, will increase the lifetime of a steam system dramatically.
Principle of Deaerators
Deaeration in deaerators is based on 2 principles. the primary principle may be delineated by Henry’s Law. As per Henry’s Law, the gas solubility during a resolution decreases because the gas partial pressure higher than the answer decreases.
The second principle that governs deaeration is that the relationship between ‘gas solubility’ Vs ‘temperature’.
Now for higher understanding, the working principle of deaerator is that the gas solubility during a resolution decreases because the temperature of the answer rises and approaches the saturation temperature.
A deaerator utilizes each of those natural processes to get rid of dissolved oxygen, CO2, and alternative non-condensable gasses from boiler feedwater. The feedwater is sprayed in skinny films into a steam atmosphere permitting it to become quickly heated to saturation.
Spraying feedwater in skinny films will increase the extent of the liquid to bear with the steam, which, in turn, provides a lot of speedy oxygen removal and lower gas concentrations.
Types of deaerators
Deaerators ar classified as 3 sorts, they are
- Spray type deaerator
- Tray type deaerator
- Vacuum type deaerator
Spray sort Deaerator
The spray type deaerator is shown within the figure. within which the Pre-deaeration of boiler feedwater is sprayed within the steam house thereby the boiler feed water deaerator operating principles contacted with the steam deaeration is taken place.
The pre-deaeration is achieved by the wading bird spraying device. below all kind operating conditions, the sprayer assures heating from the condensation to saturation temperature and an awfully giant space for mass transfer.
Because the solubility of oxygen in water at saturation conditions is much zero, oxygen transfers from the water droplets to the encircling steam.
Because the steam condensates on the water, the concentration of oxygen within the direct section of the sprayer is enlarged creating it potential to vent a little quantity of steam with a comparatively high oxygen concentration.
Final deaeration within the water tank is achieved by injection of steam within the cistern. reckoning on the conditions of the warmth source(s) used (steam, controlled hot water, steam/water mixture) one (or more) varieties of steam rake(s) ar chosen.
A properly designed steam rake, taking into consideration the hydraulics within the cistern, can lead to smart contact between water and steam, permitting the oxygen to maneuver from the water to the steam in accordance with Henry’s law.
Tray type Deaerator
The typical horizontal tray-type deaerator in Figure contains a vertical vaulted deaeration section mounted higher than a horizontal boiler feedwater storage vessel. Boiler feedwater enters the vertical separation section higher than the perforated trays and flows downward through the perforations.
The unaggressive duration steam enters below the perforated trays and flows upward through the perforations and had an honest contact with the feed water.
The steam strips the dissolved gas from the boiler feedwater and exits via the vent at the highest of the vaulted section.
The deaerated steam enters below the perforated trays and flows upward through the perforations and had an honest contact with the feed water. The steam strips the dissolved gas from the boiler feedwater and exits via the vent at the highest of the vaulted section.
The deaerated water flows down into the horizontal storage vessel from wherever it’s tense to the steam-generating boiler system. unaggressive heating steam, that enters the horizontal vessel through a sparger pipe within the bottom of the vessel, is provided to stay the keep boiler feedwater heat. Deaerator regulation and kind
Vacuum type Deaerator
The vacuum type deaerator consists of 3 main elements, they’re vacuum deaerator, an air pump unit, and a boiler feed pump unit. Deaerator construction is generally the deaeration tank that is formed from galvanized steel or chrome steel.
Within the tank is supplied with AN intermediate bottom, below that, a reservoir for deaerated water is mounted. Filter’s ar put in on high of the intermediate bottom.
A vacuum pump(liquid ring pump) is connected with the deaerator for suction the liberated dissolved gasses. Thereby maintained a negative pressure within the deaerator system to reinforce the liberation of dissolved gasses from the boiler feedwater.
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