Air separation
US4747859A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 10, 1987 |
| Grant date | May 31, 1988 |
| Priority date | — |
| Expiry date | Sep 10, 2007 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S62/924
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
Air is fractionated in a double distillation column comprising lower pressure and higher pressure columns. A condenser/reboiler provides reboiled oxygen to the bottom of the column. Liquid nitrogen reflux is introduced into the top of the column. Oxygen, nitrogen and argon-enriched streams are withdrawn from the column. The argon-enriched stream is separated in a further distillation column and a product argon stream is withdrawn therefrom. A liquid stream comprising oxygen and nitrogen is withdrawn from an intermediate level of the column, is at least partially reboiled in a heat exchanger, and is returned to the column at a level where the composition of the vapor corresponds approximately to that of the reboiled liquid. Heating for the heat exchanger is provided by a fluid stream withdrawn from the second distillation column. The fluid stream is returned to the second column. The reboiling of the stream from the intermediate level of the first distillation column enhances the efficiency of the air separation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.