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:
Aug. 18, 1992
Filed:
Apr. 26, 1991
Rakesh Agrawal, Allentown, PA (US);
Calvin L Ayres, New Tripoli, PA (US);
Air Products and Chemicals, Inc., Allentown, PA (US);
Abstract
The present invention relates to a process for liquefaction of a nitrogen stream produced by a cryogenic air separation unit. Cold liquid natural gas (LNG) is employed as refrigerant. A critical feature step of the invention is that the temperature of the vaporizing LNG should be maintained at a temperature lower than the critical temperature of the nitrogen stream being liquefied. The process involves compressing the nitrogen stream to at least 350 psi in a multistage compressor wherein interstage cooling is provided by heat exchange against vaporizing LNG. Further cooling and flashing of a portion of the liquid nitrogen stream serves to produce a quantity of liquid nitrogen that is free of hydrocarbon contamination and suitable for recycle to the air separation unit.