Integrated plants and associated processes for producing ammonia and sulfuric acid have been developed comprising air separation and water electrolysis subsystems and which make surprisingly efficient use of the products from these subsystems (i.e. oxygen and nitrogen from the former and hydrogen and oxygen from the latter). The invention is particularly suitable for use as part of an integrated fertilizer production plant.

A method for the production of air gases by the cryogenic separation of air can include the steps of sending a purified and compressed air stream to a cold box under conditions effective for cryogenically separating the air stream into oxygen and nitrogen using a system of columns, wherein the purified and compressed air stream is at a feed pressure when entering the system of columns; withdrawing the oxygen at a product pressure; delivering the oxygen at a delivery pressure to an oxygen pipeline, wherein the oxygen pipeline has a pipeline pressure; and monitoring the pipeline pressure. The method can also include a controller configured to determine whether to operate in a power savings mode or a variable liquid production mode. By operating the method in a dynamic fashion, a power savings and/or additional high value cryogenic liquids can be realized in instances in which the pipeline pressure deviates from its highest value.

An apparatus for the production of air gases with variable liquid production by the cryogenic separation of air can include a cold box having a heat exchanger, and a system of columns; a pressure monitoring device; and a controller. The cold box can be configured to receive a purified and compressed air stream under conditions effective for cryogenically separating the air stream to form an air gas product. The apparatus may also include means for transferring the air gas product from the cold box to an air gas pipeline. The pressure monitoring device is configured to monitor the pipeline pressure, and the controller is configured to adjust the product pressure of the air gas product coming out of the cold box based upon the pipeline pressure and to further adjust liquid production from the cold box based on the adjusted product pressure.

A method for the production of air gases by the cryogenic separation of air can include the steps of sending a purified and compressed air stream to a cold box under conditions effective for cryogenically separating the air stream into an oxygen product and nitrogen using a system of columns, wherein the purified and compressed air stream is at a feed pressure when entering the system of columns; withdrawing the oxygen product at a product pressure; delivering the oxygen product at a delivery pressure to an oxygen pipeline, wherein the oxygen pipeline has a pipeline pressure; wherein during the second mode of operation, the method can include monitoring the pipeline pressure; and reducing the difference between the pipeline pressure and the delivery pressure. By operating the method in a dynamic fashion, a power savings can be realized in instances in which the pipeline pressure deviates from its highest value.

The present disclosure provides a carbon-based oxygen-enriched combustion method for recirculation of flue gas from a cement kiln. The combustion method includes recirculating the flue gas generated by the cement kiln to a certain degree to concentrate and enrich carbon dioxide in the flue gas of the cement kiln, mixing the carbon dioxide-rich recirculating flue gas of the cement kiln with the pressurized oxygen to obtain the carbon-based oxygen-enriched products, and mixing the carbon-based oxygen-enriched products with the atmospheric-pressure oxygen to obtain carbon-based air which serves as combustion-supporting gas of the cement kiln.

A system for generating an inert fluid, the system being carried on board an aircraft, the generation system including a plurality of devices configured each, in succession, to execute a separation of components of a primary fluid initially collected in the form of compressed hot air, the system including at least one heat exchanger configured to execute a separation of components, by change of phase of a component of the primary fluid, executing a cooling of the primary fluid using liquid hydrogen, supplied with liquid hydrogen collected from a tank of the aircraft. It is thus possible to generate an inert gas without requiring membrane separation of the nitrogen and the oxygen, and while at the same time making it easier to warm the liquid hydrogen stored and used in the aircraft as a source of energy.

According to an embodiment of the invention, nitrogen gas of an air separation unit is used to cool the gas formed in a reservoir of liquid from an MEOH unit that is supplied with oxygen by said air separation unit.

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.

A fuel cell system using natural gas, which includes a fuel cell including a cathode and an anode and a cryogenic heat-exchanging apparatus configured to heat-exchange natural gas supplied from a natural gas station with introduced air or exhaust gas of the fuel cell. With the configuration, oxygen which is introduced into the fuel cell can be produced using cold energy of the natural gas, and energy consumed for the oxygen production can be reduced. Also, a discharge of seawater of low temperature can be minimized, thereby reducing negative effects caused by the discharge.

A novel concept for a high energy and material efficient nitric acid production process and system is provided, wherein the nitric acid production process and system, particularly integrated with an ammonia production process and system, is configured to recover a high amount of energy out of the ammonia that it is consuming, particularly in the form of electricity, while maintaining a high nitric acid recovery in the conversion of ammonia to nitric acid. The energy recovery and electricity generation process comprises pressurizing a liquid gas, such as air, oxygen and/or N.sub.2, subsequently evaporating and heating the pressurized liquid gas, particularly using low grade waste heat generated in the production of nitric acid and/or ammonia, and subsequently expanding the evaporated pressurized liquid gas over a turbine. In particular, the generated electricity is at least partially used to power an electrolyzer to generate the hydrogen needed for the production of ammonia. The novel concepts set out in the present application are particularly useful in the production of nitric acid based on renewable energy sources.