Method for separating substances from a gaseous medium by dry adsorption
US5885539A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 9, 1997 |
| Grant date | Mar 23, 1999 |
| Priority date | — |
| Expiry date | Jun 9, 2017 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB01D53/83
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
The treatment, through a dry adsorption process, of a gas from a hot electrolytic process for aluminum production comprises at least two stages. Particulate aluminum oxide (the adsorbent) passes through the stages of the adsorption process countercurrently to the gas. Thus, the gas is treated with a partly spent adsorbent in a first dry adsorption stage, whereupon the particulate adsorbent is separated from the gas downstream from the first adsorption stage. Part of the separated particulate adsorbent is removed from the adsorption process for recycling adsorbed fluorine-containing substances to the electrolytic process. The remainder of the separated adsorbent is recirculated in the first adsorption stage in order to optimize the adsorption of fluorine-containing substances and the desorption of sulfur dioxide from the aluminum oxide in this stage. Simultaneously, the gas is transferred to a second dry adsorption stage. In this second stage, the gas is treated with essentially unspent, reactive particulate aluminum oxide, so that any gaseous fluoride remaining in the gas is very efficiently adsorbed, while at the same time a substantial part of the sulfur dioxide in the gas is als…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.