Treatment of black liquor with a screw extruder evaporator
US5143579A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 31, 1991 |
| Grant date | Sep 1, 1992 |
| Priority date | — |
| Expiry date | Jul 31, 2011 |
Classification
- Technology area (CPC D)Textiles; Paper
- CPC primaryD21C11/10
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
The specification discloses a method for the treatment of black liquor from a kraft or soda pulping process which comprises forcibly conveying the black liquor through an elongate conduit containing at least one vent at a position along its length while subjecting the black liquor to a working action and maintaining the temperature of the black liquor at least about 80.degree. C. so that the black liquor is compressed and mixed as it is conveyed through the conduit to promote the separation of liquid components from the black liquor into the vent by expression and vaporization. As a result, the solids concentration of the material may be increased to provide an improved quality fuel for soda recovery boilers. The process is advantageously carried out using a vented screw extruder which is equipped to supply heat to the black liquor from the screw interiors and barrel housing to promote vaporization of volatiles and to maintain the flowability of the material as it is conveyed through the extruder.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.