Often, when liquid petroleum products like crude oil and gasoline are being transported, they need to be temporarily stored before they safely reach their destination. That’s where above ground storage tanks come in. These cylindrical structures are located along the route of an underground pipeline are designed to meet strict regulatory requirements to safely hold liquid petroleum products.
Storing petroleum liquids may not seem like an emission-creating action, but it can be an issue. Some of the petroleum components very easily evaporate into the air, even when stored at normal pressure and temperature. These components can cause ozone to form at the ground level, which can contribute to smog.
Storage tanks are often painted white to reflect the sun’s rays and reduce evaporation. The floating roof on the tanks also helps prevent evaporation, with primary and secondary seal systems that create vapour-tight barriers.
Regular inspections are done to check the condition of tank vents, drains and valves. These inspections include monitoring the condition of the seals, measuring gaps and repairing and replacing seals as required. Some products are more volatile and evaporate quickly. For certain types of liquids, vapour control and recovery systems can be used to collect over 95 per cent of vapour emissions that do occur. (show the tank diagram)