Patent ID: 7546748

Claim:
A process for separating air by cryogenic distillation using at least two subcoolers that are discrete from one another, comprising the steps of: a) compressing an air stream; b) cooling said air stream in a main heat exchanger, wherein said main heat exchanger comprises a low-pressure main heat exchanger and a high-pressure main heat exchanger; c) feeding said air stream to a system of separation columns; d) separating at least one nitrogen stream from said air stream in said system of separation columns; e) removing a first subcooler nitrogen stream and a second subcooler nitrogen stream from the system of separation columns; f) passing said first subcooler nitrogen stream through a first subcooler, wherein said first subcooler is a low-pressure subcooler, and wherein said first subcooler nitrogen stream feeds said low-pressure main heat exchanger after said first subcooler nitrogen stream passes through said low-pressure subcooler; g) passing said second subcooler nitrogen stream through a second subcooler; h) sending said first subcooler nitrogen stream to said main heat exchanger after said first subcooler nitrogen stream passes through said first subcooler; i) sending said second subcooler nitrogen stream to said main heat exchanger after said second nitrogen subcooler stream passes through said second subcooler; j) cooling at least a first process stream in said first subcooler; and k) cooling at least a second process stream in said second subcooler.