Patent ID: 7464568

Claim:
A method which may be used for the separation of air by cryogenic distillation in a system of columns, said method comprising: a) providing a system of columns comprising a double column or a triple column, wherein said column operating at the highest pressure is operating at a pressure called medium pressure; b) providing an exchange line; c) taking all the air to be distilled to a high pressure, wherein said high pressure is at least about 5 bar greater than said medium pressure; d) purifying said air at said high pressure; e) cooling at least a portion of said purified air in said exchange line, and dividing said purified air into a first and a second fraction; f) expanding said first and said second fractions in at least one turbine, wherein: 1) said turbine has an intake pressure which is at least 5 bar greater than said medium pressure; and 2) at least one said turbine has a delivery pressure substantially equal to said medium pressure; g) sending at least a portion of air from said turbine to a medium pressure column in said system of columns; h) drawing cooled air from said exchange line with a cold booster, wherein said cold booster is mechanically coupled to at least one said turbine; i) reintroducing compressed air from said cold booster to said exchange line, wherein: 1) said reintroduced air has temperature greater than an intake temperature of said cold booster; and 2) at least a portion of said reintroduced air condenses, or pseudo-condenses, in said exchange line; i) vaporizing, or pseudo-vaporizing, at least one pressurized liquid from said columns, wherein said vaporizing, or pseudo-vaporizing, occurs in said exchange line at a vaporization temperature; and k) providing an energy dissipation device, wherein: 1) said energy dissipation device is provided to at least one turbine not coupled to said cold booster; and 2) said energy dissipation device comprises at least one member selected from the group consisting of: i) a mechanically coupled booster, followed by a cooler, wherein said mechanically coupled booster is not said cold booster; ii) an oil break system; and iii) an electrical generator, wherein two said turbines have substantially the same pressure and temperature conditions in terms of intake and delivery conditions.