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.

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.

Various illustrative embodiments of a system and process for recovering high-quality biomethane and carbon dioxide product streams from biogas sources and utilizing or sequestering the product streams are provided. The system and process synergistically yield a biomethane product which meets gas pipeline quality specifications and a carbon dioxide product of a quality and form that allows for its transport and sequestration or utilization and reduction in greenhouse gas emissions. The system and process result in improved access to gas pipelines for products, an improvement in the carbon intensity rating of the methane fuel, and improvements in generation of credits related to reductions in emissions of greenhouse gases.

A full liquid-product air separation equipment is disclosed. The equipment comprises an air filtration system, a compression system, a precooling system, a purification system, a high-temperature expander having a first pressurizing part and a first expanding part, a low-temperature expander having a second pressurizing part and a second expanding part, a main heat exchanger having a first heat exchange pipeline, a second heat exchange pipeline, a third heat exchange pipeline, a fourth heat exchange pipeline and a fifth heat exchange pipeline, and a rectification system for rectifying air. The equipment has a simple configuration, is easy to implement, and has high gas separation efficiency and low energy consumption.

A nitrogen producing cryogenic air separation unit with an excess air circuit is provided. The nitrogen producing cryogenic air separation unit is capable of producing high pressure gaseous nitrogen without the use of a nitrogen product compressors and is also capable of producing high rates of liquid nitrogen without adding additional compression stages in the main air compressor and/or without a nitrogen recycle compressor.

The present disclosure provides an energy-efficient process for preparing nitrogen and oxygen for a glass melting furnace. A device required by the process includes a filter, a turbine air compressor, an air pre-cooling unit, alternately used molecular sieve adsorbers, an electric heater, a main heat exchanger, a rectifying tower I, a main condenser-evaporator I, a rectifying tower II, a main condenser-evaporator II, a rectifying tower III, a main condenser-evaporator III, a supercooler, an expander I and an expander II. The three rectifying towers are used to prepare a low-pressure nitrogen product and an oxygen product with a certain pressure at the same time. The oxygen product with a certain pressure is used for oxygen-enriched combustion for the glass melting furnace, and the low-pressure nitrogen product is used as shielding gas of a tin bath.

The present disclosure provides a method for cryogenic air separation. In the method, part (b2) of the air (b) is compressed in warm booster (7), cooled in heat exchanger (2) and then divided in two, one part (c1) being compressed in a cold booster(9) driven by one turboexpander (11) in which the other part (c2) of air (c) is expanded, and another part of the feed air is not boosted but is expanded in another turboexpander (6) which drives the warm booster (7). The present disclosure also provides an apparatus for cryogenic air separation.

A process for producing liquid oxygen, including, a first operating mode, and a second operating mode. During the first operating mode, the distillation column produces a first flowrate of product liquid oxygen, and a first flow rate of liquid nitrogen product. During the second operating mode, the distillation column produces a second flowrate of product liquid oxygen, and a second flow rate of liquid nitrogen product. Wherein, the second flowrate of product liquid oxygen is greater than the first flowrate of product liquid oxygen.

Carbon dioxide is recovered from an exhaust gas in the form of liquid carbon dioxide or supercritical carbon dioxide utilizing a rotary separator. Nitrogen gas recovered from the rotary separator can be expanded to provide cooling for carbon dioxide in a closed-loop CO2 power cycle that is used to cool the exhaust gas upstream of the rotary separator. The recovery can power itself and can produce excess electricity from waste heat.

An apparatus for producing product nitrogen gas and product argon, comprising: a first rectification column into which raw air is introduced; a second rectification column from which product nitrogen gas is drawn; a third rectification column from which product argon gas is drawn; and a first condenser configured to perform heat exchange between a gas accumulated in a column top portion of the first rectification column, and a liquid accumulated in a column bottom portion of the second rectification column, wherein an intermediate portion gas containing nitrogen is drawn from an intermediate portion of the second rectification column and merged with a condenser gas drawn from the first condenser. The merged gases are expanded and cooled by means of an expansion turbine whereby the cold thereof is utilized.