Air separation
US5438835A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 21, 1994 |
| Grant date | Aug 8, 1995 |
| Priority date | — |
| Expiry date | Apr 21, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S62/94
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A first stream of cooled and purified air is introduced into a higher pressure rectification column 12 through an inlet 14 and is separated into oxygen-enriched liquid and nitrogen vapour. A stream of the oxygen-enriched liquid is flashed through a pressure reducing valve 40 into an intermediate rectification column 22 in which it is separated into further-enriched liquid and an intermediate nitrogen vapour. A stream of the further-enriched liquid is reboiled in condenser-reboiler 46 and is introduced into a lower pressure rectifier 34 comprising an upper stage 58 and a lower stage 60. The lower pressure rectifier 34 has a bottom condenser-reboiler 16 which is heated by a second stream of cooled and purified air. The second stream is itself condensed in the reboiler 16 and is introduced into the higher pressure column 12. The lower pressure rectifier also has an intermediate condenser-reboiler 22 which is employed to form liquid nitrogen reflux for the rectification by condensing nitrogen vapour separated in the higher pressure rectification column. In alternative examples of the process, the liquid that is flashed through the valve 40 is subjected to phase separation rather than r…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.