Pulp washing process
US4595456A · kind A · utility
Inventor
Key dates
| Filing date | Nov 20, 1984 |
| Grant date | Jun 17, 1986 |
| Priority date | — |
| Expiry date | Nov 20, 2004 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02P70/10
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
The invention relates to a process for the washing of pulp with a maximum recovery of energy, the pulp after digestion being washed in a plurality of successive washing steps at a pressure above atmospheric in at least one of the steps and washing filtrate from a following step or fresh water being used as diluting and washing liquid in a given step. The outgoing washing filtrate from a washing step should be heat exchanged against incoming diluting and washing liquid to the subsequent step and a part of the filtrate (21) from the second step should be heat exchanged against washing filtrate (10) from the first step and then be combined with cooking liquor (23) for the digestion of the pulp. As diluting and washing liquids in the last two steps (4, 5), fresh water is used, which has also been heat exchanged against outgoing washing filtrate (54, 10) from the last and the first washing step. The gases leaving the washing steps are heat exchanged (25, 36, 47) against fresh water, which is then used as the diluting and washing liquid in the last step, the gases (11) from the first step however being heat exchanged against cooking liquor (8) for the digestion process. The condensates (…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.