Continuous digester and feeding system

Patent metadata

Field	Value
Publication number	US-9644317-B2
Application number	US-201414554105-A
Country	US
Kind code	B2
Filing date	Nov 26, 2014
Priority date	Nov 26, 2014
Publication date	May 9, 2017
Grant date	May 9, 2017

Abstract

One embodiment provides an apparatus for cooking lignocellulosic material, comprising a pressurizable, inclined top separator including a sluicing liquor inlet for receiving a sluicing mixture comprising impregnated lignocellulosic material and sluicing liquor, a hot black liquor inlet, an excess liquor outlet, and an impregnated lignocellulosic material outlet; a continuous digester vessel including an impregnated lignocellulosic material inlet in communication with the impregnated lignocellulosic material outlet, and a warm black liquor outlet; and a black liquor circulation and heating loop including a warm black liquor inlet in communication with said warm black liquor outlet, a heater for heating warm black liquor to produce hot black liquor, and a hot black liquor outlet in communication with said hot black liquor inlet. Methods of making and using the apparatus are also provided.

First claim

The invention claimed is:

1. An apparatus for cooking lignocellulosic material, comprising:
a pressurizable, inclined top separator including a sluicing liquor inlet for receiving a sluicing mixture comprising impregnated lignocellulosic material and sluicing liquor, a hot black liquor inlet, an excess liquor outlet, and an impregnated lignocellulosic material outlet;
a continuous digester vessel including an impregnated lignocellulosic material inlet in communication with the impregnated lignocellulosic material outlet, and a warm black liquor outlet; and
a black liquor circulation and heating loop including a warm black liquor inlet in communication with said warm black liquor outlet, a heater for heating warm black liquor to produce hot black liquor, and a hot black liquor outlet in communication with said hot black liquor inlet.

2. The apparatus of claim 1 , wherein the inclined top separator further comprises one or more of a screen or screw and is adapted to separate impregnated lignocellulosic material from at least a portion of sluicing liquor.

3. The apparatus of claim 1 , wherein the inclined top separator includes an upper end and a lower end; the impregnated lignocellulosic material outlet being disposed at the upper end; and the sluicing liquor inlet being disposed at the lower end.

4. The apparatus of claim 1 , wherein the inclined top separator is adapted to operate at a pressure of 4-15 bar.

5. The apparatus of claim 1 , wherein the inclined top separator, sluicing liquor inlet, or both are adapted to receive sluicing mixture at a temperature of 50-130° C.

6. The apparatus of claim 1 , wherein the sluicing mixture further comprises one or more of white liquor, spent cooking liquor, water, or a combination thereof.

7. The apparatus of claim 1 , wherein the inclined top separator is adapted to heat impregnated lignocellulose material to a temperature of 60-185° C.

8. The apparatus of claim 1 , wherein the inclined top separator is adapted to cool or maintain white liquor, excess liquor, or both to or at a temperature of 60-130° C.

9. The apparatus of claim 1 , wherein the inclined top separator, hot black liquor inlet, or both are adapted to receive hot black liquor at a temperature of 140-185° C.

10. The apparatus of claim 1 , wherein the inclined top separator is adapted to operate at a pressure and temperature condition below the boiling point of sluicing liquor, white liquor, excess liquor, hot black liquor, or combination of two or more thereof.

11. The apparatus of claim 1 , wherein the inclined top separator is adapted to convey impregnated lignocellulosic material to the impregnated lignocellulosic material outlet at a temperature above the boiling point at ambient pressure of sluicing liquor, white liquor, excess liquor, hot black liquor, or combination of two or more thereof but at a pressure sufficient to prevent boiling of sluicing liquor, white liquor, excess liquor, hot black liquor, or combination of two or more thereof.

12. The apparatus of claim 1 , wherein the inclined top separator is adapted to convey impregnated lignocellulosic material to the impregnated lignocellulosic material outlet.

13. The apparatus of claim 1 , wherein the inclined top separator is adapted to convey the impregnated lignocellulosic material to said impregnated lignocellulosic material outlet at a temperature of 60-185° C.

14. The apparatus of claim 1 , wherein the inclined top separator is adapted to convey impregnated lignocellulosic material and at least a portion of white liquor to the impregnated lignocellulo sic material outlet.

15. The apparatus of claim 1 , wherein the inclined top separator is adapted to convey impregnated lignocellulosic material, hot black liquor, and at least a portion of white liquor to the impregnated lignocellulosic material outlet.

16. The apparatus of claim 1 , wherein the inclined top separator is adapted to convey impregnated lignocellulosic material, hot black liquor, and one or more of sluicing liquor, white liquor, or a combination thereof to the impregnated lignocellulosic material outlet.

17. The apparatus of claim 1 , wherein the inclined top separator is adapted to combine impregnated lignocellulosic material with hot black liquor.

18. The apparatus of claim 1 , wherein the digester vessel is a vapor-phase digester or hydraulic digester.

19. The apparatus of claim 1 , wherein the digester vessel is a single vessel digester or a two-vessel digester.

20. The apparatus of claim 1 , wherein the digester vessel is adapted to produce cooked pulp from impregnated lignocellulose material.

21. The apparatus of claim 1 , wherein the digester vessel is adapted to operate at a temperature of 140-185° C.

22. The apparatus of claim 1 , wherein the digester vessel is adapted to operate at a pressure of 4-15 bar.

23. The apparatus of claim 1 , wherein the digester vessel further comprises a steam inlet, cooked pulp outlet, or both.

24. The apparatus of claim 1 , wherein the digester vessel includes an upper end and a lower end; the impregnated lignocellulosic material inlet being disposed at the upper end; a cooked pulp outlet being disposed at the lower end; and the warm black liquor outlet being disposed between the upper end and lower end.

25. The apparatus of claim 1 , wherein the black liquor circulation and heating loop further comprises a white liquor inlet, an excess liquor inlet in communication with the excess liquor outlet, a circulation pump, or a combination of two or more thereof.

26. The apparatus of claim 1 , wherein the black liquor circulation and heating loop is adapted to operate at a pressure of 4-15 bar.

27. The apparatus of claim 1 , wherein the heater is adapted to receive and heat warm black liquor having a temperature of 130-180° C. to produce hot black liquor having a temperature of 140-185° C.

28. The apparatus of claim 1 , further comprising an ambient pressure impregnation vessel in communication with the sluicing liquor inlet and adapted to produce impregnated lignocellulose material.

29. The apparatus of claim 28 , wherein the impregnation vessel is adapted to impregnate lignocellulose material at ambient pressure and at a temperature below the boiling point of white liquor, excess liquor, weak black liquor, or a combination of two or more thereof.

30. The apparatus of claim 1 , claim 28 , wherein the ambient pressure impregnation vessel comprises a sluicing mixture outlet in communication with the sluicing liquor inlet of the inclined top separator.

31. A process, comprising producing a cooked pulp in the apparatus of claim 1 .

32. A process for cooking pulp in the apparatus of claim 1 , comprising
introducing, under pressure, a sluicing mixture comprising impregnated lignocellulosic material and sluicing liquor into the pressurizable, inclined top separator;
heating and separating, under pressure, the impregnated lignocellulosic material in the inclined top separator from at least a portion of the sluicing liquor, to produce heated impregnated lignocellulosic material; and
conveying, under pressure, the heated impregnated lignocellulosic material to the continuous digester vessel, and cooking, to produce a cooked pulp;
wherein said pressures in the introducing, heating, separating, and conveying are sufficient to pr

Assignees

• Int Paper Co

Inventors

• Mccanty Kevin M

Classifications

• D21C7/00

  Digesters · CPC title

• D21C7/06 Primary

  Feeding devices · CPC title

• D21C3/00 Primary

  Pulping cellulose-containing materials (digesters D21C7/00) · CPC title

• D21C11/0021

  Introduction of various effluents, e.g. waste waters, into the pulping, recovery and regeneration cycle (closed-cycle) · CPC title

• D21C7/14

  Means for circulating the lye · CPC title