Claims
- 1. A digester for continuously cooking and digesting cellulosic material and producing cellulosic pulp comprising:
a plurality of jump-stage recirculations located along the length of a continuous digester vessel, wherein each of the jump-stage recirculations moves extracted liquor from a first elevation of the digester vessel and re-introduces the extracted liquor into the vessel at a second higher elevation to maintain an internal liquor downflow substantially throughout the entire digester vessel.
- 2. The digester of claim 1, wherein the internal liquor downflow does not exceed 400 gallons per ton of b.d. wood feed substantially throughout the entire digester vessel.
- 3. The digester of claim 1 further comprising a plurality of liquor extraction and addition points along the length of the digester.
- 4. The digester of claim 3 further comprising a flow-indicator-control system associated with each jump-stage recirculation and liquor extraction and addition points.
- 5. The digester of claim 1, wherein the digester vessel comprises a plurality of extraction screens along the length of the vessel, each extraction screen having a jump-stage recirculation.
- 6. A digester for continuously cooking and digesting cellulosic material and producing cellulosic pulp comprising:
a jump-stage recirculation located along the length of a continuous digester vessel, wherein the jump-stage recirculation moves extracted liquor from a first elevation of the digester vessel and re-introduces the liquor into the vessel at a second higher elevation to maintain an internal liquor downflow substantially throughout the entire vessel that does not exceed 400 gallons per ton of b.d. wood feed.
- 7. The digester of claim 6 further comprising a plurality of liquor extraction and addition points along the length of the digester.
- 8. The digester of claim 7 further comprising a flow-indicator-control system associated with the jump-stage recirculation and liquor extraction and addition points.
- 9. A process for continuously cooking and digesting cellulosic material and producing cellulosic pulp in a continuous digester comprising:
(a) maintaining an internal, con-current liquor downflow substantially throughout a continuous digester vessel, wherein the internal liquor downflow does not exceed 400 gallons per ton of b.d. wood feed.
- 10. The process of claim 9, wherein the continuous digester vessel comprises a plurality of jump-stage recirculations located along the length of the vessel, and each of the jump-stage recirculations moves extracted liquor from a first elevation of the digester vessel and re-introduces the extracted liquor into the vessel at a second higher elevation to maintain the internal liquor downflow substantially throughout the entire digester vessel.
- 11. The process of claim 9, wherein the continuous digester vessel comprises a plurality of liquor extraction and addition points along the length of the digester.
- 12. The process of claim 11, wherein the continuous digester vessel further comprises a flow-indicator-control system associated with each jump-stage recirculation and liquor extraction and addition points.
- 13. The digester of claim 9, wherein the digester vessel comprises a plurality of extraction screens along the length of the vessel, each extraction screen having a jump-stage recirculation.
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to and the benefit of U.S. patent application Ser. No. 60/240,659, filed Oct. 16, 2000, which is hereby incorporated by reference in its entirety.
Provisional Applications (1)
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Number |
Date |
Country |
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60240659 |
Oct 2000 |
US |