The present invention relates to a process and a system for supplying a backup gas at a higher pressure from a source gas at a lower pressure. The backup gas at the lower pressure is at least partially condensed against a backup liquid at a higher pressure in a reprocessing heat exchanger and as a result, the backup liquid is at least partially vaporized. The backup liquid at the higher pressure is formed from boosting liquefied backup gas at the lower pressure. A backup vaporizer is disposed downstream of the reprocessing heat exchanger to completely vaporize the backup liquid at a higher pressure before it was delivered to the customer. The present invention eliminates the use of costly gas compressor and mitigates associated safety risks, in particular when the backup gas is oxygen.

In a method for reheating an atmospheric vaporizer, a cryogenic liquid is vaporized by heat exchange with ambient air in the atmospheric vaporizer and to reheat the vaporizer, a gas is sent thereto at a temperature of at least 0° C., this gas originating from a cryogenic distillation air separation unit.

A method for temperature-controlled delivery of the gaseous product at temperatures at or below ambient in the event of an air separation unit failure. In one embodiment, a first portion of a stored cryogenic liquid product is sent to the back-up vaporizer and heated to ambient conditions, and a second portion of stored cryogenic liquid product, which is at the cryogenic storage temperature, bypasses the back-up vaporizer using a bypass line controlled by a bypass valve and is mixed with the vaporized gas. This mixed stream will then preferably go through a static mixer in order to get to an homogenous temperature that is below the ambient temperature. A temperature control loop can be used to adjust the opening of the by-pass valve in order to reach the desired product temperature.

A system and method for removing nitrogen from natural gas using two fractionating columns, that may be stacked, and a plurality of separators and heat exchangers, with horsepower requirements that are 50-80% of requirements for prior art systems. The fractionating columns operate at different pressures. A feed stream is separated with a vapor portion feeding the first column to produce a first column bottoms stream that is split into multiple portions at different pressures and first column overhead stream that is cooled and separated into vapor and liquid portions to control subcooling of the vapor portion prior to feeding the second column. Heat exchange between first column and second column streams provides first column reflux and reboil heat for a second column ascending vapor stream. Three sales gas streams are produced, each at a different pressure.

A liquefier device which may be a retrofit to an air separation plant or utilized as part of a new design. The flow needed for the liquefier comes from an air separation plant running in a maxim oxygen state, in a stable mode. The three gas flows are low pressure oxygen, low pressure nitrogen, and higher pressure nitrogen. All of the flows are found on the side of the main heat exchanger with a temperature of about 37 degrees Fahrenheit. All of the gasses put into the liquefier come out as a subcooled liquid, for storage or return to the air separation plant. This new liquefier does not include a front end electrical compressor, and will take a self produced liquid nitrogen, pump it up to a runnable 420 psig pressure, and with the use of turbines, condensers, flash pots, and multi pass heat exchangers. The liquefier will make liquid from a planned amount of any pure gas oxygen or nitrogen an air separation plant can produce.

A liquefier device which may be a retrofit to an air separation plant or utilized as part of a new design. The flow needed for the liquefier comes from an air separation plant running in a maxim oxygen state, in a stable mode. The three gas flows are low pressure oxygen, low pressure nitrogen, and higher pressure nitrogen. All of the flows are found on the side of the main heat exchanger with a temperature of about 37 degrees Fahrenheit. All of the gasses put into the liquefier come out as a subcooled liquid, for storage or return to the air separation plant. This new liquefier does not include a front end electrical compressor, and will take a self produced liquid nitrogen, pump it up to a runnable 420 psig pressure, and with the use of turbines, condensers, flash pots, and multi pass heat exchangers. The liquefier will make liquid from a planned amount of any pure gas oxygen or nitrogen an air separation plant can produce.

A natural gas power generation process with zero carbon emission is described. The process includes pressurizing air and introducing the pressurized air into an air separation facility to obtain liquid oxygen and liquid nitrogen. The liquid oxygen is used for gasification and power generation The liquid nitrogen is applied as a coolant of flue gas, and then for gasification and power generation.

In a method for reheating an atmospheric vaporizer, a cryogenic liquid is vaporized by heat exchange with ambient air in the atmospheric vaporizer and to reheat the vaporizer, a gas is sent thereto at a temperature of at least 0 C., this gas originating from a cryogenic distillation air separation unit.

The present disclosure relates to the technical field of natural gas power generation, and particularly discloses a natural gas combined power generation process with zero carbon emission, the process comprising: introducing the pressurized air into an air separation facility to obtain liquid oxygen and liquid nitrogen, wherein the liquid oxygen is used for gasification and power generation, the liquid nitrogen is applied as the coolant of flue gas, and then used for the gasification and power generation; the liquid nitrogen and a part of liquid oxygen stored during the valley period with low electricity load are provided for use during the peak period with high electricity load; the natural gas, oxygen and the recyclable CO.sub.2 jointly enter a combustion gas turbine for burning to drive an air compressor and a generator to rotate at a high speed, the air compressor compresses the air to a pressure of 0.40.8 MPa, the generator generates electricity; the high-temperature combustion flue gas performs the supercritical CO.sub.2 power generation, its coolant is liquid oxygen; the moderate temperature flue gas then exchanges heat with liquid nitrogen, the liquid nitrogen vaporizes for power generation, the cooled flue gas is dehydrated and subjects to distillation and separation to obtain the recovered CO.sub.2, a part of the CO.sub.2 can be returned for circulation and temperature control, another part of the CO.sub.2 may be used for replenishment of work medium for supercritical CO.sub.2 power generation, and the remaining part of CO.sub.2 may be sold outward as liquid CO.sub.2 product. During the peak period with high electricity load, the liquid nitrogen stored during the valley period with low electricity load and separated during the peak period is pumped and pressurized and then subjects to heat exchange and vaporization for power generation. The power generation process provided by the present disclosure not only solves the difficult problems in the existing natural gas combined power generation technology such as high water consumption, low power generation efficiency and small range of peak load adjustment capacity; but also can compress air with high unit volume for energy storage with a high conversion efficiency, and greatly reduce load of the air compressor, thereby perform CO.sub.2 capture and utilization with low cost, zero NO.sub.x emission and discharging fuel gas at a normal temperature, and significantly improve the power generation efficiency.

A method for separating air by cryogenic distillation in a system of columns comprising a first column and a second column operating at a lower pressure than the first column, comprising the steps of compressing all of the feed air in a first compressor to a first output pressure of at least 1 bar greater than the pressure of the first column, sending a first portion of the air under the first output pressure to the second compressor, and compressing the air to a second output pressure, cooling and condensing at least a portion of the air under the second output pressure in a heat exchanger, withdrawal of a liquid from a column of the system of columns, pressurising the liquid and evaporating the liquid by heat exchange in the heat exchanger, and pressure reduction of a portion of the compressed air to a second output pressure, at least partially evaporating said air in the heat exchanger, optionally additional heating of said air in the heat exchanger, and sending at least a portion of this air to the second compressor.