The elimination of dissolved gasses from a particular boiler feed water is a crucial process in the steam system. The existence of dissolved oxygen in feed water can lead to swift localized corrosion in every boiler tube. The dissolved carbon dioxide in a liquid which can cause low pH levels and the production of the corrosive carbonic acid.
Though dissolved gasses and low pH levels are present in the feed water, it can still be controlled or eliminated by adding a few chemicals. This is more practical and more efficient to remove these gasses appropriately. This kind of mechanical process is called deaeration. It is called deaerator if the process is taking place in a vessel.
By eliminating the dissolved gasses in the boiler feedwater, it expands the life of the steam process accordingly.
Understand the Principle Deaerators
Deaeration and deaerators are derived from two principles. The first one is described according to Henry’s Law. The gas solubility in a particular solution reduces as the temperature of the solution lifts and advanced towards the saturation temperature.
A deaerator uses the two natural approach to eliminate dissolved carbon dioxide, oxygen, and other gasses from the boiler. The feed water is sprinkled in a thin layer into the steam firmament, enabling it to become heated to saturation.
Spraying Feedwater into thin layers intensify the surface area of the liquid in connection with the steam, which gives more rapid oxygen elimination in proximity and lower gas centralization. This method lessens the solubility of every dissolved gas and eliminates it from the boiler feedwater. For the extricate gasses, it vented out from the deaerator.
Different Types of Deaerators
Deaerators can be categorized into three types:
- The spray type deaerator
- The vacuum type deaerator
- The Tray type deaerator
Spray Type Deaerator
The spray type deaerator is when the pre-deaeration process of the boiler feedwater is sprinkled in the steam atmosphere. The spraying equipment acquires the pre-deaeration process. Under different kinds of industrial conditions, the sprayer ensure that the process is achieved accordingly. When the solubility of the oxygen became zero, the oxygen will be transferred from the water droplets into the steam atmosphere.
Vacuum Type Deaerator
This type of deaerator consists of three primary components: vacuum pump unit, vacuum deaerator, and boiler feedwater pump unit.
Generally, the deaeration tank is built from a stainless or galvanized steel. Inside the tank vessel, you’ll found an intermediate bottom which is a supply for deaerated liquid.
Tray Type Deaerator
In this type of deaerator, the boiler feedwater will enter the vertical section of deaeration at the top of the perforated trays and will flow on the downward position. In addition to that, the stream from the dissolved gasses that came from the boiler Feedwater will exit through the vent above the domed section.