Why nitrogen blanketing on oil tanks?

Blenketing is widely used in industries for protection and process safety. Oil is blanketed in the tank to avoid oxidation of the oil, which leads to earlier degradation (very important if the oil is used as a heating utility) of the utility. Nitrogen blanketing is usually triggered by the temperature, for most thermal oil starts to degrade at around 60 deg C.

In the food industry, oil product is used also as a blanket to prevent spoilage and also as a blanket to prevent air infiltrating the tank. Also, positive pressure is kept to avoid any iinfiltration from the outside of the tank.