Top circulation line cooling for a modified cook digester
US5302247A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 2, 1992 |
| Grant date | Apr 12, 1994 |
| Priority date | — |
| Expiry date | Nov 2, 2012 |
Classification
- Technology area (CPC D)Textiles; Paper
- CPC primaryD21C7/14
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
In the production of cellulose pulp (e.g. kraft pulp) utilizing a continuous digester having a number of different feed points for cooking (e.g. white) liquor and utilizing a high pressure feeder, the volume of cool white liquor that is applied to the feed system is reduced compared to conventional processing. This can cause excessive hammering, and damage the high pressure feeder and adjacent piping and equipment. In order to avoid this, liquid being recirculated from the top of the digester back to the high pressure feeder is cooled by passing it into a heat exchanger into heat exchange relationship with a cooler liquid, with the flow of coolant automatically controlled by sensing the temperature of the recirculated liquid. The temperature in the feed system can further be lowered by cooling the cooking liquor before it is added to the pulp slurry, as by passing it to a flash tank so that its temperature is reduced at least 10.degree. C., and the flashed steam can be used in an evaporator.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.