Processes and apparatuses for recovering a high purity carbon dioxide stream. A first separation zone that may include a cryogenic fractionation column provides the high-purity CO.sub.2 stream. A vapor stream from the cryogenic fractionation column is passed to a second separation zone to separate the CO.sub.2 from the other components. The second separation zone may include a pressure swing adsorption unit or a solvent separation unit. The second separation zone provides a hydrogen enriched gas stream that may be used in a gas turbine. The second stream from the second separation zone includes carbon dioxide and, after a pressure increase in a compressor, may be recycled to the first separation zone.

The invention relates to a method and also a device for producing a gas product, wherein a first gas stream is combined with a second gas stream and the first gas stream that is present at a lower output pressure than the second gas stream is fed to a mechanical compressor in order to be compressed to the preset pressure of the gas product. It is characteristic in this case that the pressure of the first gas stream is elevated using a gas jet compressor arranged upstream of the mechanical compressor, to which gas jet compressor at least a part of the second gas stream is fed as pumping medium.

A heat integration method, including providing a hot gas stream, wherein the hot gas stream includes carbon dioxide and at least one gas from the following: carbon monoxide, nitrogen, and oxygen. Recovering waste heat from the hot gas stream by producing a steam stream by indirect heat exchange, and utilizing the steam stream in a carbon capture system, wherein the carbon capture system includes a cryogenic partial condensation step. Wherein the carbon capture system produces a product carbon dioxide stream.

A process for removing CO.sub.2 from a methane-containing gas, having the steps of providing a methane-containing gas containing at least CO.sub.2 as an impurity, cooling the gas to remove CO.sub.2 from the methane-containing gas by freezing out same, and additionally reducing the CO.sub.2 concentration of the gas using a pressure temperature swing adsorption apparatus (PTSA), whereby a methane-enriched product gas is obtained. At least a part of the product gas is then used as treatment gas and is passed through the PTSA for treatment of the PTSA, whereby CO.sub.2 is absorbed by the treatment gas and is removed from the PTSA as a CO.sub.2-enriched treatment gas. The treatment gas is then recycled and admixed with the methane containing gas.

In a process in which ammonia is cracked to form a hydrogen gas product and an offgas comprising nitrogen gas, residual hydrogen gas and residual ammonia gas, residual ammonia is recovered from the offgas from the hydrogen recovery process by partial condensation and phase separation, and hydrogen is recovered from the resultant ammonia-lean offgas by partial condensation and phase separation. The recovered ammonia may be recycled the cracking process and the recovered hydrogen may be recycled to the hydrogen recovery process to improve hydrogen recovery from the cracked gas. Overall hydrogen recovery from the ammonia may thereby be increased to over 99%.

The present application belongs to the field of environmental protection, and in particular to a system and method for simultaneously producing high-purity liquid nitrogen and high-purity liquid carbon dioxide at low cost by using flue gas. The system provided by the present application comprises a flue gas boosting and cooling system, a CO.sub.2/N.sub.2 front-end separation system, a liquid CO.sub.2 preparation system and a high-purity liquid nitrogen preparation system The present application can maximize the use of flue gas to produce high-purity liquid nitrogen and liquid CO.sub.2 at low cost, and realize the synchronous resource utilization of carbon/nitrogen components.

Processes and systems are provided for treating the tail gas stream of a sulfur recovery plant. The process comprising the steps of treating the compressed tail gas stream in a pre-treatment unit to remove the impurities; separating the dry stream in a first stage membrane unit, the first stage membrane unit comprises a membrane selective to carbon dioxide and hydrogen; reducing a temperature of the cryogenic feed in a cryogenic cooler to produce a cryogenic stream; separating the cryogenic feed in a knock-drum to produce a liquid carbon dioxide and membrane feed; separating the membrane feed in a second stage membrane unit to produce a rubbery membrane permeate and a rubbery membrane retentate, where the second stage membrane unit comprises a membrane selective to carbon dioxide over hydrogen; and treating the rubbery membrane retentate in a hydrogen recovery process to produce a hydrogen product stream and a carbon dioxide lean stream.

A method for separating hydrogen and nitrogen from a gas mixture, including a) thereby partially condensing a hydrogen and nitrogen gas mixture and producing a two-phase stream, b) phase separating the two-phase stream, producing a nitrogen-enriched liquid fraction and a hydrogen-enriched gaseous fraction, c) expanding the nitrogen-enriched liquid fraction, producing a lower-pressure nitrogen-enriched liquid or two-phase stream, d) adding heat to the lower-pressure nitrogen-enriched liquid stream, producing a warm nitrogen enriched gaseous stream, and e) adding heat to the hydrogen-enriched gaseous fraction, producing a hydrogen-rich product stream. Wherein, at least a portion of the heat added in step d) is removed in step a), at least a portion of the heat added in step e) is removed in step a), or at least a portion of the heat added in step d) and at least a portion of the heat added in step e) is removed in step a).

A process for separating carbon dioxide from a waste gas of a fluid catalytic cracking installation including converting at least a portion of the carbon monoxide of the waste gas into carbon dioxide to form a flow enriched in carbon dioxide, separating at least a portion of the flow enriched in carbon dioxide to form a gas enriched in carbon dioxide and depleted in nitrogen and a gas rich in nitrogen and depleted in carbon dioxide, and at least a portion of the gas enriched in carbon dioxide and depleted in nitrogen is separated by way of separation at a temperature of less than 0 C. to form a fluid rich in carbon dioxide and a fluid depleted in carbon dioxide and sending a gas containing at least 90% oxygen to combustion.

A method of producing hydrogen from a hydrocarbon feedstock is provided. Wherein, at least a portion of a fuel stream comprises a superheated ammonia stream. And, at least: a first portion of a hydrogen-rich stream is combined with a shifted syngas stream prior to introduction into a pressure swing adsorber, a second portion of the hydrogen-rich stream is combined with the fuel stream prior to introduction into a steam methane reformer, and/or a third portion of the hydrogen-rich stream is combined with a hydrocarbon containing feedstock stream and a steam stream prior to introduction into a feed pre-heater. Heat integration between the ammonia vaporization and superheating steps is employed to cool process streams to minimize and even eliminate a dedicated cryogenic refrigeration system.