Process for purifying a gas stream of its N2O impurities

US6273939A · kind A · utility

Assignee

• L'Air Liquide, Societe Anonyme Pour l'Etude et l'Exploitation des Procedes Georges Claude · FR

Inventors

• Cyrille Millet · Paris, FR
• Serge Moreau · Vélizy-Villacoublay, FR
• Georges Kraus · Paris, FR
• Jean-Pierre Gabillard · Auffargis, FR

Key dates

• Filing date: Oct 20, 1999
• Grant date: Aug 14, 2001
• Expiry date: Oct 20, 2019

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S95/902
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

A process, particularly of the TSA type, for separating impurities of the nitrogen protoxide (N.sub.2 O) and possibly carbon dioxide (CO.sub.2) or ethylene (C.sub.2 H.sub.4) type which are contained in a gas stream, such as air. The impurities of nitrogen protoxide type are removed on a faujasite zeolite having a Si/Al ratio of 1 to 1.5 and containing from 0 to 35% of K.sup.+ cations, between 1 and 99% of Na.sup.+ cations and between 1 and 99% of Ca.sup.2+ cations, preferably at least 50% of Ca.sup.2+ cations. The separation is preferably carried out at a temperature of approximately -40.degree. C. to +80.degree. C., preferably at room temperature. Advantageously, the process is employed for prepurifying atmospheric air before cryogenic distillation of the air thus prepurified.