Method for regenerating scale solvent
US5087371A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 14, 1990 |
| Grant date | Feb 11, 1992 |
| Priority date | — |
| Expiry date | Nov 14, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG21F9/002
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
Barium sulfate scale is dissolved by contacting the scale with an aqueous solvent having a pH of about 8 to about 14, containing a chelating agent comprising a polyaminopolycarboxylic acid or salt of such an acid, and a synergist anion. The aqueous solvent containing the dissolved scale is regenerated by first acidifying the aqueous solvent sufficiently to generate free alkaline earth metal ions. The aqueous solvent is then mixed with a liquid membrane emulsion enveloped around droplets of an internal aqueous phase containing an anion that forms an insoluble precipitate with the free alkaline earth metal ions. The scale-free aqueous solvent is separated from the emulsion by gravity and recovered for reuse. In another embodiment, the internal aqueous phase may contain a chelating agent to remove the free alkaline earth metal ions by forming a stable complex with the ions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.