Vapor-tight tank

A vapor-tight tank is a piece of portable onshore oil production equipment designed to store crude oil and convey oil vapors to a flare stack.
Vapor-tight tanks are horizontal vessels that can usually hold up to 14.7 pounds per square inch . They use that pressure to force oil vapors to the flare. Connection to a flare allows these systems to be operated in situations with a high hydrogen sulfide content. In fact, their original intended use was sour crude oil production. The first vapor-tight tanks were constructed from used crude oil tank cars by Tornado Technologies.
Vapor-tight tanks are frequently packaged with an integral separator, flare stack, and other equipment to form a complete single-well battery. Because of their small size and portability, they are mostly used in temporary production of oil wells.
Canadian regulations consider that vapor-tight tanks are process vessels, rather than storage tanks, so tankage spacing and secondary containment provisions are not applicable.