The present invention relates to a cryogenic air separation process that provides high pressure oxygen for an oxy-fired combustion of a fuel (e.g., a carbonaceous fuel). The air separation process can be directly integrated into a closed cycle power production process utilizing a working fluid, such as CO.sub.2. Beneficially, the air separation process can eliminate the need for inter-cooling between air compression stages and rather provide for recycling the adiabatic heat of compression into a process step in further methods wherein an additional heat supply is beneficial.

The invention relates to a unit and method for melting in a furnace comprising a combustion-heated melting chamber, in which the air is heated by means of heat exchange with the fumes generated by combustion. The heated air is used in a gas turbine in order to generate electrical and/or mechanical energy. In addition, the effluent from the gas turbine is used to pre-heat the combustion oxygen and/or gaseous fuel upstream of the melting chamber.

A method includes compressing an air flow to a first pressure, transferring heat from the air flow to a liquefaction fluid via an intercooler heat exchanger, compressing the air flow to a second pressure greater than the first pressure, combusting the air flow and a fuel to generate a combustion product flow, and driving a turbine with the combustion product flow. The turbine is configured to drive machinery of a liquefaction system. The liquefaction fluid includes at least one of a pre-cooling fluid, a refrigerant, and a liquefied product of the liquefaction system.

An apparatus for compressing air and producing a carbon dioxide-rich fluid includes an air compressor, an element for bringing the air bound for the air compressor into contact with water to produce humidified air and cooled water, a pipe for sending the humidified compressed air from the air compressor to an installation producing a carbon dioxide-rich gas, a carbon dioxide-rich gas compressor for compressing the carbon dioxide-rich gas, at least one heat exchanger upstream and/or downstream the carbon dioxide-rich gas compressor and pipes for conveying into the heat exchanger water cooled in the contact element and the carbon dioxide-rich gas.

A method for separating a gas mixture at subambient temperature, in which a gas mixture is sent to a heat-insulated chamber, cooled and separated in a column, and placed inside the chamber so as to produce at least two fluids, each of which is enriched with a component from the gas mixture. At least one fluid from the method can be heated inside the chamber or vaporized via heat exchange with at least one heating member including at least one element having magnetocaloric properties and built into a circuit configured to conduct a magnetic flux. The element is alternatingly in thermal contact with a cold source, made up of the fluid to be heated, and a hot source, made up of a source hotter than the fluid to be heated, and variation in the magnetic flux via the magnetocaloric effect generates electrical and/or mechanical energy.

A method and an apparatus for a cooling of an electroyzer unit is described. The apparatus receives a temperature value associated with ambient air in proximal to the electrolyzer unit. The apparatus compares the temperature value with a predefined temperature threshold. The apparatus controls a supply of a liquid air stream from an air separation unit to a first heat exchanger unit based on the comparison. The apparatus control the first heat exchanger unit to mix the liquid air stream with the ambient air. The mixing of the liquid air stream and the ambient air causes transfer of heat therebetween. The apparatus controls a cooling of the electrolyzer unit based on the mixing.

A method for providing a nitrogen product, an oxygen product and a hydrogen product, wherein an air separation installation is used which is designed for the low-temperature separation of feed air and which has a rectification column system, the rectification column system comprising an air-fed rectification column and a main heat exchanger. The provision of the nitrogen product comprises, in particular, subjecting feed air to low-temperature rectification using the air-fed rectification column such that a tops gas is obtained, and using part of the tops gas as the nitrogen product. The provision of the oxygen product and the hydrogen product comprises subjecting water to water electrolysis in an electrolyzer, such that a water-containing oxygen stream and a hydrogen stream are obtained, the water-containing oxygen stream or part thereof being subjected, at least in one operating phase, to drying and, in an unmixed state, to liquefaction in the air separation installation.

A system that integrates a power production system and an energy storage system represented by gas liquefaction systems is provided.