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:
Nov. 04, 1997
Filed:
Jul. 19, 1996
Teisan Kabushiki Kaisha, Tokyo, JP;
Abstract
Ultra-high purity nitrogen is generated by removing, from feed air, carbon dioxide, moisture and catalyst poisons of an oxidation catalyst contained therein by a decarbonating drier (4). The feed air is then introduced into a low-pressure rectification column (6), where it is roughly rectified to further remove the carbon dioxide, moisture and catalyst poison. Then raw nitrogen gas obtained in the low-pressure rectification column (6) is introduced into an oxidation column (8) so that carbon monoxide in the raw nitrogen gas is converted to carbon dioxide and hydrogen also contained therein to water. Thereafter the raw nitrogen gas is introduced into an adsorption column (10) so that carbon dioxide and water are removed by adsorption to provide feed raw nitrogen gas, which is fed into an intermediate-pressure rectification column (11), where it is rectified. Nitrogen gas from the top portion of the intermediate-pressure rectification column is condensed by a reboiler-condenser (6RC) to provide high purity liquid nitrogen; and the liquid nitrogen is returned to the intermediate-pressure rectification column (11), whereby a part of this high purity liquid nitrogen is used as a reflux liquid and the remaining part thereof is taken out of a rectifying stage that is several stages below the rectifying stage in the top portion of the intermediate-pressure rectification column as an ultra-high purity nitrogen gas product or ultra-high purity liquid nitrogen product.