Tank blanketing or padding, refers to applying a cover of gas over the surface of a stores commodity; usually a liquid.
Purpose
- Prevent volatile vapours from escaping
If the liquid is volatile it is used to protect or contain the stored product and prevent it from harming personnel, equipment, or the environment. It can maintain the atmosphere above a flammable or combustible liquid to reduce ignition potential. - Prevent oxidization (oxygen entering)
If the liquid can be oxidized it protects it from oxidation or contamination through exposure to air or moisture. - Prevent corrosion
It prevents outside air, moisture, and other contaminents from entering and causing corrosion.
It can also reduce the moisture content - Maintaining constant pressure
If for some reason the tank suddenly cools, the vapours inside the tank will suddenly condense causing the the tank pressure to decrease.
The blanketing is typically set for as low as possible ( minimize the consumption of 2 in of H20) to minimize the wastage of blanketing gas.