Apparatus for minimizing effluent discharges and recovering chemicals in a pulp mill
US5547543A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 12, 1994 |
| Grant date | Aug 20, 1996 |
| Priority date | — |
| Expiry date | Jul 12, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S162/08
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
Apparatus for a pulp and paper mill, and methods of acting on liquid effluents produced in the mill, which minimizes the discharge of polluting gaseous and liquid effluents to the environment. Liquid effluents from the bleach plant are concentrated (e.g. evaporated), incinerated (e.g. gasified), leached, crystallized (e.g. freeze crystallized) then washed, and then fed to the plant chemical recovery loop. White liquor produced from the recovery boiler melt is fully oxidized and used in place of caustic in the bleach plant. Essentially all sulfuric acid, sulfur dioxide, caustic, and chlorine dioxide necessary for the pulp mill is produced from mill liquid effluents and gas waste streams, on site at the pulp mill. Typical bleaching sequences that can be used are DE.sub.op D.sub.n D, or AZE.sub.o PZP.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.