Method for treating waste saline water produced in production process of diphenylmethane diisocyanate (MDI)
US9802848B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 17, 2009 |
| Grant date | Oct 31, 2017 |
| Priority date | — |
| Expiry date | Sep 24, 2032 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC02F2103/36
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
The invention relates to a method of circular use of waste brine produced in the manufacture process of MDI, comprising the following steps: (1) the waste brine produced in the manufacture process of MDI is subjected to a high-gravity extraction and then to a column extraction, wherein said waste brine contains aniline, diaminodiphenylmethane and polyamine; (2) the waste brine from step (1) is transmitted to a stripping tower for steam stripping; (3) the waste brine from the stripping tower of step (2) and a chemical oxidant are transmitted to an oxidation reactor to which air is blown for aeration; (4) the waste brine after the treatment of step (3) is transmitted to an absorption tower for absorption. The invention makes the salt water have TOC of less than 8 ppm and TN of less than 2.5 ppm and achieves regeneration of resources in the waste brine such as sodium chloride and water and the like for circular use.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.