METHOD OF PRODUCTION OF COLD Russian patent published in 1997 - IPC

FIELD: low-pressure air separation plants with circulating cycles for production of oxygen, nitrogen and argon. SUBSTANCE: water fed to scrubber is cooled in heat exchanger by nitrogen flows of main and circulating cycles; after they have been preheated to positive temperatures, circulating flow is formed which is directed for compression. Specific feature of proposed method consists in possibility of mounting the fractionating towers of medium and low pressures at one level when liquid nitrogen is fed from circulating cycle as reflux to medium-pressure tower for fractionation; pure gaseous nitrogen is taken from upper portion of tower and is directed to condenser for evaporation of liquid oxygen; part of liquefied pure nitrogen is fed to low-pressure tower for fractionation. Proposed method of separation of air may be widely used for production of liquid oxygen, nitrogen and argon at change of their quantitative ratio. EFFECT: reduction of power consumption and capital outlays. 3 cl, 1 dwg