Abstract: A method and apparatus to remove vapor from a storage tank comprising introducing a stream of gas into the storage tank to cause mixing of the vapor within the tank. The stream of gas is preferably introduced into the storage tank through a gas nozzle that increases the velocity of the gas. Furthermore, the gas nozzle may have a fixed or variable orientation that introduces the stream of gas to flow into a region of the storage tank to prevent retention of the vapor in that region. A mixture of the vapor and the gas is withdrawn from the storage tank through an outlet port and provided to an abatement unit, such as a condenser or burner. Where the abatement device is a condenser, the gas and any uncondensed vapor may be returned to the storage tank through the gas nozzle, or through a second gas nozzle.

Abstract: Volatile vapors are removed from a storage vessel by establishing a flow of a stream of volatile vapors from the storage vessel and directing the stream through a first low temperature condenser for condensing a portion of the stream flowing through the first low temperature condenser. Since a portion of the condensed condensate freezes and causes a pressure drop in the first low temperature condenser, further steps may include directing the stream from the first low temperature condenser through a second low temperature condenser after the pressure drop exceeds a setpoint, stopping the flow of the refrigerant through the first low temperature condenser and using the heat of the volatile vapor stream to melt the frozen condensate in the first low temperature condenser. The stream is switched between the condensers as necessary to prevent excessive plugging due to frozen condensate formation. The system includes the means for implementing the method.