Abstract: A method of recovering hydrocarbons from a storage vessel by utilizing two or more heat exchangers is disclosed. A stream of vapors from the vessel is directed first through a first heat exchanger and then through a second heat exchanger where a portion of the vapors is condensed. The pressure drop between either the inlet of the first heat exchanger or the inlet of the second heat exchanger and the outlet of the second heat exchanger is monitored to detect frozen condensate in the second heat exchanger. When the pressure drop increases to a level requiring remediation, the pressure drop is remediated by redirecting a relatively warm portion of the stream to a portion of the second heat exchanger containing the frozen condensate to melt the frozen condensate.

Abstract: A fugitive emissions abatement system for use a storage tank 4 with a floating roof assembly 10 comprises a roof structure 12, a first peripheral seal 70 slidably engaging an interior surface 4A of the tank 4 to form an annular gas chamber 60 intermediate the first peripheral seal 70 and the liquid level 50 within the tank 4, and an aperture 78 in the first peripheral seal 70 coupled to the first end 82 of a fluid conduit 80. The second end 81 of the fluid conduit 80 may be coupled to the inlet of a gas mover 88 so that operation of the gas mover 88 draws gas from the annular gas chamber 60 through the fluid conduit 80 so that it can be delivered to a processing apparatus that may include, but is not limited to, a compressor, a vessel, a heat exchanger and/or an incinerator.

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 A mixture of the vapor and the gas is withdrawn from the storage tank through an outlet port and provided to an abatement unit, such as a condenser or burner.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.

Abstract: A mobile method and apparatus for venting volatile organic compound vapors from a liquid storage vessel which includes the steps of introducing a purge medium to a liquid storage vessel containing volatile organic compound vapors and establishing an uniform and continuous stratified interface between the purge medium and the volatile organic compound vapors. The introduction of the purge medium is continued causing the continuous stratified interface to move within the vessel purging the virtually undiluted volatile organic compound vapors from the vessel and into a vapor recovery line which delivers the volatile organic compound vapors to a vapor control device. Preferably, the purge medium comprises carbon dioxide or nitrogen.

Abstract: A method and apparatus for venting volatile organic compound vapors from a liquid storage vessel which includes the steps of introducing a purge medium to a liquid storage vessel containing volatile organic compound vapors and establishing an uniform and continuous stratified interface between the purge medium and the volatile organic compound vapors. The introduction of the purge medium is continued causing the continuous stratified interface to move within the vessel purging the undiluted volatile organic compound vapors from the vessel and into a vapor recovery line which delivers the volatile organic compound vapors to a vapor handling device. Preferably, the purge medium comprises carbon dioxide or nitrogen.

Abstract: A method and apparatus for venting volatile organic compound vapors from a liquid storage vessel which includes the steps of introducing a purge medium to a liquid storage vessel containing volatile organic compound vapors and establishing an uniform and continuous stratified interface between the purge medium and the volatile organic compound vapors. The introduction of the purge medium is continued causing the continuous stratified interface to move within the vessel purging the undiluted volatile organic compound vapors from the vessel and into a vapor recovery line which delivers the volatile organic compound vapors to a vapor handling device. Preferably, the purge medium comprises carbon dioxide or nitrogen.