How to remove the oxygen in a boiler with sodium sulphite?

1.Why is it necessary to remove the oxygen in a boiler?

When the metal of the heating surface  of the boiler is accumulated  with dirt, because the heat cannot be transferred to the water in time,

the temperature of the metal surface is high, where the protective film is destroyed and is corroded by the oxygen dissolved in the water, forming the iron oxide dirt Fe (OH)₃ ï¼ˆferric hydroxide）and Fe₃O₄（ferriferrous oxide）.

2.What is the principle of deoxidization  with sodium sulphite?

Using sodium sulphite to deoxidize is a simple, low-investment, easy-operating and non-toxic and harmless method. The principle of boiler on is that sodium sulphite is a reducing agent, which can react with dissolved oxygen  in water to produce sodium sulphite.

2Na₂SO₃+O₂—→Na₂SO₄

The free oxygen in the water is fixed by the reducing agent sodium sulphite and cannot oxidize the metal iron, protecting the boiler from corrosion.

3.How is it done?

As can be seen from the molecular formular above, one portion of oxygen needs eight portions of sodium sulphite to deoxidize.In practical operation, normally a 2% ~ 10% solution is prepared and added using a pump  or dosing dish.

Since Na₂SO₃ can react with the oxygen in the air, the dosing system used should be insulated from the air.