Process for the separation of a gas mixture by cryogenic distillation
AssigneeL'Air Liquide, Societe Anonyme pour l'Etude et l'Exploitation des Procedes Georges Claude
InventorsPhilippe Fraysse, Mike De L'Isle, Daniel Rousseau
Life of this patent
Estimating the term…
Abstract
In order to precool a flow of gas to be distilled, before a purification stage, it is sent into an exchanger (5) where it is cooled by heating a flow of refrigerant (13B). At least a part of this refrigerant has its pressure reduced before cooling the unpurified gas and may be a fraction of the gas to be distilled or a product of the distillation. It is preferably a cycle gas of the system. This arrangement makes it possible to obviate a refrigerating unit.
Claims21
Process for the separation of a gas mixture containing nitrogen and oxygen by distillation in a cryogenic apparatus, comprising:
- compressing the gas mixture in a compression stage;
- purifying the compressed gas mixture with respect to water and carbon dioxide in a purification stage so as to obtain a purified gas mixture;
- cooling the purified gas mixture to close to its dew temperature;
- distilling the cooled gas mixture in at least one distillation column;
- and
- supplying the cooling power of the apparatus by a refrigeration system in which at least a part of the gas mixture is cooled between the compression and purification stages by indirect heat exchange with a flow of refrigerant which is a product of the distillation column or which constitutes a part of the gas mixture to be distilled, wherein liquid is produced as a final product and the pressure of at least a part of the refrigerant is reduced in a pressure-reduction machine before said refrigerant exchanges heat with unpurified gas mixture.
Installation for the separation of a gas mixture containing nitrogen and oxygen by cryogenic distillation, comprising:
- a compressor having an inlet for feeding the gas mixture and an outlet for compressed gas mixture;
- an auxiliary exchanger fluidly connected to said outlet;
- a purification system fluidly connected to said auxiliary exchanger;
- a main exchanger fluidly connected to said purification system;
- at least one distillation column fluidly connected to said main exchanger;
- a refrigeration system operatively associated to said auxiliary exchanger, to said main exchanger, and to said distillation column;
- said auxiliary exchanger including means for placing the compressed gas mixture in thermal exchange with a refrigerant originating from the distillation column or from a feed downstream of the purification system;
- and
- said installation further including means for withdrawing a liquid product, and a pressure-reduction machine for reducing the pressure of at least a part of the refrigerant upstream of the auxiliary exchanger.
Dependencies are inferred from the claim text.