Tank blanketing of process and storage vessels is widely used to protect equipment, plant personnel, and the products themselves. Blanketing helps to prevent air, moisture, and other contaminants from entering the tank. It protects the tank from structural damage, and the product from spoilage and evaporation. A blanketing gas, nitrogen being the most popular, serves to reduce the oxygen content in the vapor space, making it inert and eliminating the possibility of combustion.
Vapor recovery systems are mainly used to prevent tank vapors from escaping into the atmosphere. When adding liquid to the tank or when the outside temperature rises causing the vapor inside the tank to expand, the vapor recovery system senses the increase in tank pressure and vents the excessive tank pressure to a safe place.