A system and method for producing two or more nitrogen product streams and a crude argon stream from a nitrogen and argon producing air separation unit is provided. The disclosed embodiments of the cryogenic-based nitrogen and argon producing air separation units and associated air separation cycles include the means for directing a first portion of a boil-off stream from an argon condenser of the air separation unit to a waste expansion refrigeration circuit and concurrently recycling a second portion of the boil-off stream from the argon condenser to the main air compression system of the air separation unit to be mixed or blended with the incoming feed air. Optionally, a third portion of the boil-off stream from the argon condenser may be further compressed in a cold compressor and returned to the lower pressure column.

A system and method for improving the performance of an oxygen, nitrogen, and argon producing air separation unit configured to produce a gaseous nitrogen product stream is provided. By recycling the argon condenser boil-off vapor stream to the main air compression train, the argon recovery and oxygen recovery while maintaining the production level of a medium or high pressure gaseous nitrogen product stream. In addition, some operational cost savings in terms of lower power costs can also be realized compared to some prior art oxygen, nitrogen, and argon producing air separation units.

A method and a device for producing an air product based on cryogenic rectification; after being cooled by a main heat exchanger, raw material air and nitrogen compressed by means of a compressor are sent to a rectification system for low temperature separation. In the rectification system, products such as oxygen and nitrogen are obtained by means of low temperature separation, and oxygen-enriched liquid air is obtained at or near the bottom of a rectification tower. The oxygen-enriched liquid air or liquid-state air in the rectification system is sent out after being raised to a target pressure by means of a low temperature liquid air pump; air products of various pressures can be produced by means of selecting low temperature liquid air pumps with different lifts or by connecting in series different amounts of low temperature liquid air pumps. The present method can avoid the need to arrange additional air compressors, entirely changing the method for producing medium and high pressure air products in a nitrogen circulation process, and importantly can reduce production costs significantly whilst having greater flexibility. In addition, the present method can increase the oxygen extraction rate of an apparatus, thereby improving the energy efficiency level.

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 process for providing an oxygen product using an air separation plant having a distillation column system, in which a cryogenic liquid is withdrawn from the distillation column system, wherein a first portion of the cryogenic liquid is subjected to a pressure-increasing evaporation by evaporating a second portion of the cryogenic liquid, and the oxygen product is provided using at least part of the first portion of the cryogenic liquid. At least part of the evaporated second portion of the cryogenic liquid, after the increase in pressure, is made available for further utilization, for the provision of the oxygen product. The present invention also relates to a corresponding air separation plant.

The invention relates to a process for low-temperature separation of air, in which an air separation plant having a first rectification column and a second rectification column is used, the first rectification column being supplied with cooled compressed air and the second rectification column being supplied with liquid from the first rectification column or liquid formed herefrom. By means of a first condenser-evaporator, head gas of the first rectification column is condensed and liquid from the second rectification column or liquid formed herefrom is evaporated, thereby producing a first evaporation product. The invention also relates to a corresponding air separation plant.

A method of cleaning a condensate thermosyphon reboiler including modifying a flow rate of a hot oil stream introduced into the tube-side of a first condensate thermosyphon reboiler, modifying a flow rate of a condensate hydrocarbon stream introduced into the shell-side of the first condensate thermosyphon reboiler, and maintaining an operation of the condensate stabilizer system until the value of an overhead temperature of the first condensate thermosyphon reboiler is detected to have been modified from the first overhead temperature to a second overhead temperature. The method further includes modifying the flow rate of the condensate hydrocarbon stream from the second condensate flow rate to the first condensate flow rate, and modifying the flow rate of the hot oil stream from the second hot oil flow rate to the first hot oil flow rate.

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.