1. INTRODUCTION
Deaerator tanks are an enclosed feed water heater that is used to eliminate dissolved gases, mainly carbon dioxide and oxygen out of the water feed. It boosts the efficiency of boilers as well as prevents pitting and corrosion and extends the life of boilers.
2. WORKING PRINCIPLE
It is the method of eliminating gas dissolved from water by heating it until it is near saturation and also by coming into direct contact with steam.
The water that is fed into the deaerator, and it is then sprayed as small droplets via the spray nozzle.
* Steam from the extraction pipeline is released back into tank and is in contact with droplets of water.
* Steam is used to heat the water until it reaches a near-saturation temperature.
* Gases that dissolve are released because of high temperatures, and escape through the vent steam.
• Deaerated (oxygen unrestricted) warm water gathered at the bottom before being is then sent to the boiler.
3. DEAERATOR TANK - 3D DIAGRAM
The main components are ventilation outlet, steam intake levels indicator, spraynozzle feeding water intake, perforated plates, internal baffle, manhole, and an outlet for deaerated water.
4. INTERNAL ARRANGEMENT (SECTIONAL VIEW)
Internal arrangement includes the steam intake, water feed intake and baffle plate vent, and the deaerated water outlet.
5. FUNCTIONS OF DEAERATOR TANK
1. Get rid of carbon dioxide from feed water.
2. Protects against internal pitting and corrosion of the steam boilers and steam systems.
3. Provide hot water to the boiler to increase the efficiency of the boiler.
4. Reduces the use of chemicals.
5. Storage capacity for feed water.
6. OPTIMUM OPERATING CONDITIONS
Pressure: 0.2 to 0.7 kg/cm2 (Gauge)
Temperature: 98degC to 102degC (Near Saturation)
Feed Water Temperature: 30degC to 45degC
pH (Hot Well): 8.5 to 9.2
Residual Oxygen: 0.007 mg/L (7 ppb)
DO (Dissolved Oxygen) as low as feasible
7. CHEMICAL DOSING IN DEAERATOR / BOILER WATER
* Oxygen Scavenger (Sodium Sulphite): 20-40 ppm
* pH Conditioner (Morpholine): 10-30 ppm
* Phosphate (Trisodium Phosphate): 10-30 ppm
* Internal Treatment (Tannin/Lignin): 20-50 ppm
* Anti-Foaming Agent (Silicone Based): 1-5 ppm
8. ADVANTAGES
* Enhances the efficiency of boilers.
* Prevents pitting and corrosion.
* Boosts the boiler's life.
* Lowers the use of chemicals.
* Ensuring safe and reliable operation.
9. PRECAUTIONS
* Maintain proper level in tank.
* Ensure proper steam pressure.
* Keep the vent line open and free of obstructions.
* Check regularly the your spray nozzle and perforated plates.
* Check the pH and DO frequently.
10. SUMMARY FLOW
Feed Water (From BFP) - Deaerator Tank (Heating + Deaeration) - Deaerated Hot Water - Boiler Feed Pump - Boiler Drum
