Gas separation
US4772420A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 13, 1987 |
| Grant date | Sep 20, 1988 |
| Priority date | — |
| Expiry date | Jul 13, 2007 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02P20/151
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A raw ammonia synthesis gas, preferably containing an excess of nitrogen, is converted to synthesis ready ammonia synthesis gas by two pressure swing adsorption (PSA) stages operated in succession. If the raw gas contains carbon monoxide this is chemically removed, e.g. by methanation, between the PSA stages. In the first PSA stage, CO.sub.2 is removed and waste gas from the second PSA stage is preferably fed back to the first PSA stage for sweeping, purging or repressurizing. In a preferred system the first PSA cycle includes a sweep with CO.sub.2 -rich gas prior to depressurization and purge with second PSA waste gas. In the second PSA stage inert medium boiling gases, and any unwanted nitrogen are removed as the waste gas.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.