Process for removing alkalinity and hardness from waters
US4235715A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 16, 1979 |
| Grant date | Nov 25, 1980 |
| Priority date | — |
| Expiry date | Feb 16, 1999 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC02F1/42
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
Raw water is fed to a first column containing a weak acid cation exchange resin in hydrogen form where alkalinity causing ions and hardness causing ions to the extent of alkalinity are converted to carbonic acid. The carbonic acid, which hydrolyzes to dissolved carbon dioxide, is stripped from the water in a decarbonation unit by passing air countercurrent to the flow of water through the unit. The water is then fed to a second column containing a weak acid cation exchange resin in sodium form which removes residual hardness causing ions along with neutralization of any mineral acids or residual dissolved carbon dioxide. Both resins are substantially completely regenerated upon exhaustion to provide a process in which the maximum capacities of the resins are utilized, and the process is carried out with a minimum of monitoring and control.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.