Process for cleaning wastewaters from melamine plants
US8673158B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 13, 2006 |
| Grant date | Mar 18, 2014 |
| Priority date | — |
| Expiry date | Jan 15, 2029 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC02F2103/38
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
The invention relates to a method for purifying wastewaters of melamine systems. The method is characterized in that triazine-containing wastewater is subjected to a thermal pretreatment stage, whereupon the vapors are condensed from the gas phase of the thermal pretreatment stage, and the liquid phase of the thermal pretreatment stage is subjected to a thermal hydrolysis stage while NH3 is isolated from the obtained liquid phase containing H2O, CO2, and NH3. The inventive method makes it possible to compensate varying wastewater qualities, thus allowing the melamine system and wastewater station to be operated in a constant and safe fashion. Furthermore, the strain on the subsequent thermal hydrolysis stage is relieved with the aid of the thermal pretreatment stage of the inventive method.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.