Process for removing nitrogen from LNG

US5505049A · kind A · utility

Assignee

• The M.W. Kellogg Company · US

Inventors

• David A. Coyle · Houston, US
• Felix J. Fernandez de la Vega · Houston, US
• Charles A. Durr · Houston, US
• Ashutosh Rastogi · New Delhi, IN

Key dates

• Filing date: May 9, 1995
• Grant date: Apr 9, 1996
• Expiry date: May 9, 2015

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F25J2240/40
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

A process for removing nitrogen from liquefied natural gas (LNG) using an enhanced surface, reflux heat exchanger is disclosed. A relatively warm high pressure LNG stream is directed countercurrently in heat exchange with a cool low pressure LNG stream to chill the high pressure stream and partially vaporize the low pressure LNG stream in the reflux heat exchanger. Vapor produced thereby strips the low pressure LNG stream of nitrogen. The cool low pressure LNG stream is produced by expansion of the chilled high pressure LNG stream. Vapor produced by the expansion is combined with the vapor produced in the exchanger and withdrawn overhead. Product LNG which is lean in nitrogen is withdrawn from the bottom of the exchanger.