The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 03, 1996
Filed:
Nov. 28, 1995
Thomas Rathbone, Farnham, GB;
The BOC Group plc, Windlesham, GB;
Abstract
A stream of air is compressed in compressor and has water vapor and carbon dioxide removed therefrom in purification unit. A part of the resulting purified air is cooled by passage through heat exchanger and is employed to heat an intermediate reboiler in a lower pressure rectification column. The air flow from the reboiler passes into a higher pressure rectification column which supplies a stream of oxygen-enriched liquid air for separation in the lower pressure rectification column. Liquid nitrogen reflux for the higher pressure column is provided by taking nitrogen vapor from this column through an outlet and condensing it in another intermediate reboiler located above the reboiler in the lower pressure rectification column. The condensed nitrogen is returned to the top of the column. Another air stream is employed to reboil a further reboiler at the bottom of the lower pressure rectification column with the resulting condensed air stream being introduced into the higher pressure rectification column through an inlet. An impure oxygen product is withdrawn from the bottom of the lower pressure rectification column through outlet in liquid state and is vaporized in the heat exchanger. The arrangement of reboilers facilitates operation of the apparatus with a relatively low pressure ratio between the operating pressure of the higher pressure rectification column and that of the lower pressure rectification column.