A high volume cryogen vaporizer includes a radiator where a working fluid draws heat from ambient air for vaporizing a cryogen in a heat exchanger. An electrical heater is provided for periodically heating the working fluid to defrost the radiator, thereby allowing sustained operation of the vaporizer. When not required for defrosting the radiator, the heater may be operated to heat a working fluid in a circuit separate from that of the radiator, and in which the heated working fluid is used for further elevating the temperature of the vaporized cryogen in a second heat exchanger, thereby making possible a gas output temperature higher than ambient air temperature.
A liquid cryogen vaporizer is devised in which the cryogenic liquid is first partially vaporized in a cryogenic heat exchanger which is provided with heat from nonfired sources. The partially vaporized liquid cryogen is then completely vaporized in a second downstream cryogenic heat exchanger also provided with heat from the nonfired sources. The nonfired sources comprise an internal combustion engine and an ambient air heat exchanger. The internal combustion engine drives a hydraulic circuit which provides a constant load on the engine. A cryogenic pump used to flow the cryogenic liquid through the cryogenic heat exchanger is in turn hydraulically driven from this circuit. Heat is also transferred from the hydraulic circuit into a heat exchanging circuit. The heat exchanging fluid is driven around the heat exchanging circuit by means of a pump driven by the engine through the ambient air heat exchanger, a hydraulic heat exchanger and the first cryogenic heat exchanger. Engine coolant is provided to the second cryogenic heat exchanger. A defrost heat exchanger is also provided with engine coolant and it periodically flushed with heat exchanging fluid to provide a predetermined quantity of heated fluid to defrost said ambient air heat exchanger.
A method for withdrawing from a vessel pressurized cryogenic helium fluid with an objectionable impurity concentration of less than 5 ppmv. The method comprises pressurizing at or near the top of the vessel with helium fluid from an external source having a concentration of up to 1000 ppmv of the objectionable impurity, and withdrawing from a port near the bottom of a vessel helium fluid at a cryogenic temperature below the temperature at which the withdrawn fluid has an objectionable impurity of 5 ppmv.
A process for vaporizing liquefied natural gas including passing water into a water tower so as to elevate a temperature of the water, pumping the elevated temperature water through a first heat exchanger, passing a circulating fluid through the first heat exchanger so as to transfer heat from the elevated temperature water into the circulating fluid, passing the liquefied natural gas into a second heat exchanger, pumping the heated circulating fluid from the first heat exchanger into the second heat exchanger so as to transfer heat from the circulating fluid to the liquefied natural gas, and discharging vaporized natural gas from the second heat exchanger.
Method and apparatus for vaporizing cryogenic fluids in which an intermediate heat transfer fluid is first heated across a heat transfer surface with ambient air, and then the heat transfer surface provides heat to vaporize the cryogenic fluid.
A gas supply system comprising an atmospheric vaporizer and a powered heat exchanger in series each having a rated capacity at least equal to the design gas usage rate.
