Process and apparatus for generating high-purity nitrogen by low-temperature fractionation of air

US6499313B2 · kind B2 · utility

Assignee

• Linde GmbH · DE

Inventors

• Ralph Spoeri · Geretsried, DE
• Stefan Lochner · Grafing, DE

Key dates

• Filing date: Sep 13, 2001
• Grant date: Dec 31, 2002
• Expiry date: Sep 13, 2021

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F25J2250/04
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

High-purity nitrogen is generated by low-temperature fractionation of air in a rectification system for nitrogen/oxygen separation having at least a first rectifier column (4). Cycle nitrogen (24) in gas form is removed from the upper region of the first rectifier column (4) and is compressed in a cycle compressor (30). A first part (35) of the compressed cycle nitrogen is liquefied. A nitrogen fraction (52) from the rectification system for nitrogen/oxygen separation is introduced (52) into a high-purity nitrogen column (39) having a top condenser (54). High-purity nitrogen (56) is removed from the upper region of the high-purity nitrogen column (39). The refrigeration demand of the top condenser (54) is at least partially covered by liquefied cycle nitrogen (38).