Fractional deionization process
US7338600B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 7, 2005 |
| Grant date | Mar 4, 2008 |
| Priority date | — |
| Expiry date | Dec 7, 2025 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC02F2201/46125
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A liquid treatment process is described for sequential removal of ionic species of progressively decreasing ionic strength without precipitation or “scaling.” An aspect of the invention includes two or more electrodeionization operations within one or more electrodeionization stacks. The first electrodeionization operation is performed at a voltage calculated to remove strongly ionized species such as calcium and magnesium from the feed water without scaling. The product of the first electrodeionization operation is then subjected to a second electrodeionization operation. The second electrodeionization operation is performed at a voltage the same as the first electrodeionization operation, and is designed to remove more weakly ionized species such as silica and carbon dioxide, preventing scaling. More than two successive electrodeionization operations may be performed if desired. Multiple electrodeionization operations may occur in a single electrodeionization stack or in multiple electrodeionization stacks.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.