Method for transforming diverse pulp and paper products into a homogenous cellulosic feedstock

• US 6,306,248 B1
• Filed: 11/20/1997
• Issued: 10/23/2001
• Est. Priority Date: 11/20/1997
• Status: Expired due to Term

• Current Assignee: Clean Conversion Technologies, Inc.
• Original Assignee: University of Alabama in Huntsville (University of Alabama System)
• Inventors: Eley, Michael H.
• Primary Examiner(s): Chin, Peter
• Application Number:
  US08/974,698
• Time in Patent Office: 1,433 Days
• Field of Search: 162/4, 162/21, 162/17, 162/55, 162/51, 162/15, 162/68, 209/903, 71/14, 71/11, 127/37, 952/30, 952/35
• US Class Current: 162/4
• CPC Class Codes: D21B 1/12 by wet methods, by the use of steam beaters D21D1/00
• CPC Class Codes: D21B 1/32 of waste paper
• CPC Class Codes: Y02W 30/64 Paper recycling

Abstract

A method for treating diverse pulp and paper products to produce a homogenous cellulosic feedstock comprises the steps of feeding diverse pulp and paper products into a vessel, introducing steam into the vessel while agitating the products, purging the gases from the vessel while agitating the products, sealing the vessel so that the vessel is pressure tight, saturating the products with steam at sufficient temperature and pressure to expand molecular structure of the products, while agitating the products, depressurizing the vessel to further enhance the molecular expansion of the products, and discharging the processed products. Alternatively, the method can be performed without purging the gases, if the temperature in the range of about 287° F. to about 312° F., and the pressure is in the range of about 40 to 65 psig. During the optional purging step, during the depressurization step, and during the optional evacuation step, volatile organic compounds and other air pollutants can be captured and treated.

Claims

1. A method for treating diverse pulp and paper products derived from waste paper or MSW to produce a homogenous cellulosic feedstock, comprising the steps of:

feeding diverse pulp and paper products into a vessel;

introducing steam into the vessel while agitating the products;

purging gases from the vessel through a vent valve while agitating the products;

capturing said gases and treating the gases to render any volatile organic compounds and any other air pollutants present in the gases harmless;

sealing the vessel so that the vessel is pressure tight;

saturating the products with steam at sufficient temperature and pressure to expand molecular structure of the products, while agitating the products;

depressurizing the vessel to further enhance the molecular expansion of the products; and

discharging the processed products therefrom.

2. The method of claim 1 wherein the pulp and paper products are derived from municipal solid waste.

3. The method of claim 1 wherein the method further includes the step of classifying cellulosic components of the processed products from other components.

4. The method of claim 3 wherein the step of classifying includes the step of separating the cellulosic components based on particle size.

5. The method of claim 4 wherein the step of classifying includes the step of separating the cellulosic components based on density.

6. The method of claim 5 wherein the step of classifying includes the step of separating the cellulosic components based on both particle size and density.

7. The method of claim 1 wherein the method further includes the steps of separating larger size components of the processed products and recycling the larger size components through the vessel for more processing.

8. The method of claim 1 wherein the method further includes the step of introducing the steam from the depressurized vessel into a second vessel containing diverse pulp and paper products for purging gases from the second vessel prior to full treatment of the products within the second vessel.

9. The method of claim 8 wherein the method further includes the steps of discharging processed products from each of a plurality of the vessels into a common conveyed stream, separating larger components from smaller components in the stream, and recycling the larger components through at least one of the vessels.

10. The method of claim 1 wherein the saturating step occurs at a temperature in the range of about 287°

F. to about 312°

F.

11. The method of claim 1 wherein the saturating step occurs at a pressure in the range of about 40 psig to about 65 psig.

12. The method of claim 1 wherein the pulp and paper products have a moisture content of about 20% to about 60% by weight prior to the step of introducing steam.

13. The method of claim 1 wherein the temperature and pressure are maintained for a time sufficient for the products to be uniformly mixed and transformed into the homogenous cellulosic feedstock.

14. The method of claim 13 wherein the time is in the range of about 30 to about 60 minutes.

15. The method of claim 1 wherein the vessel includes a common opening serving as an inlet and outlet and the steps of feeding the diverse pulp and paper products into the vessel and discharging the diverse pulp and paper products from the vessel are both accomplished through the common opening.

16. The method of claim 15 wherein the vessel includes two or more internally mounted helical flights, the rotation of which agitates the pulp and paper products.

17. The method of claim 16 wherein the rotation of the helical flights in one direction causes the products to move away from the common opening.

18. The method of claim 17 wherein the rotation of the helical flights in a second direction causes the products to move toward the common opening.

19. The method of claim 15 wherein the vessel is capable of being tilted such that the common opening is positioned to not permit the products to fall out of the vessel.

20. The method of claim 15 wherein the vessel is capable of being tilted such that the common opening is positioned to permit the processed products to fall out of the vessel.

21. The method of claim 1 wherein the step of depressurizing the vessel includes the step of recovering any steam remaining in the vessel.

22. The method of claim 1 wherein the step of recovering steam further includes the steps of condensing the steam and treating any condensable pollutants to render them harmless.

23. The method of claim 1 wherein the step of recovering the steam includes the step of recycling the steam.

24. The method of claim 1 wherein the step of depressurizing the vessel includes the steps of cooling and drying the processed products, and capturing any volatile organic compounds or any other air pollutants remaining in the vessel.

25. The method of claim 24 wherein the step of capturing volatile organic compounds and other air pollutants further includes the step of treating the volatile organic compounds and other air pollutants to render the volatile organic compounds and other air pollutants harmless.

26. The method of claim 24 wherein the step of cooling and drying further includes an evacuation step.

27. The method of claim 1 wherein said processed products are transported for use as a fuel or fertilizer.

28. A method for treating diverse pulp and paper products derived from waste paper or MSW to produce a homogenous cellulosic feedstock comprising the steps of:

feeding diverse pulp and paper products into a vessel;

sealing the vessel so that the vessel is pressure tight;

injecting steam into the vessel while agitating the products;

saturating the products with steam at a temperature in the range of about 287°

F. to about 312°

F. and at a pressure in the range of about 40 psig to about 65 psig to expand the molecular structure of the products;

depressurizing the vessel to further enhance the molecular expansion of the products;

capturing any gases released during said depressurizing and treating said gases to render any volatile organic compounds and any air pollutants presents in the gases harmless; and

discharging the processed products therefrom.

29. The method of claim 28 wherein the pulp and paper products are derived from municipal solid waste.

30. The method of claim 28 wherein the method further includes the step of classifying cellulosic components of the processed products from other components.

31. The method of claim 30 wherein the step of classifying includes the step of separating the cellulosic components based on particle size.

32. The method of claim 31 wherein the step of classifying includes the step of separating the cellulosic components based on density.

33. The method of claim 30 wherein the step of classifying includes the step of separating the cellulosic components based on both particle size and density.

34. The method of claim 28 wherein the method further includes the steps of separating larger size components of the processed products and recycling the larger size components through the vessel for more processing.

35. The method of claim 28 wherein the method further includes the step of introducing the steam from the depressurized vessel into a second vessel containing diverse pulp and paper products for purging gases from the second vessel prior to full treatment of the products within the second vessel.

36. The method of claim 35 wherein the method further includes the steps of discharging processed products from each of a plurality of the vessels into a common conveyed stream, separating larger components from smaller components in the strewn, and recycling the larger components through at least one of the vessels.

37. The method of claim 28 wherein the pulp and paper products have a moisture content of about 20% to about 60% by weight prior to the step of introducing steam.

38. The method of claim 28 wherein the temperature and pressure are maintained for a time sufficient for the products to be uniformly mixed and transformed into the homogenous cellulosic feedstock.

39. The method of claim 38 wherein the time is in the range of about 30 to about 60 minutes.

40. The method of claim 28 wherein the vessel includes a common opening serving as an inlet and outlet and the steps of feeding the diverse pulp and paper products into the vessel and discharging the diverse pulp and paper products from the vessel are both accomplished through the common opening.

41. The method of claim 40 wherein the vessel includes two or more internally mounted helical flights, the rotation of which agitates the pulp and paper products.

42. The method of claim 41 wherein the rotation of the helical flights in one direction causes the products to move away from the common opening.

43. The method of claim 41 wherein the rotation of the helical flights in a second direction causes the products to move toward the common opening.

44. The method of claim 41 wherein the vessel is capable of being tilted such that the common opening is positioned to not permit the products to fall out of the vessel.

45. The method of claim 41 wherein the vessel is capable of being tilted such that the common opening is positioned to permit the processed products to fall out of the vessel.

46. The method of claim 28 wherein the step of depressurizing the vessel includes the steps of cooling and drying the processed products, and capturing any volatile organic compounds or any other air pollutants remaining in the vessel.

47. The method of claim 46 wherein the step of capturing volatile organic compounds and other air pollutants further includes the step of treating the volatile organic compounds and other air pollutants to render the volatile organic compounds and other air pollutants harmless.

48. The method of claim 46 wherein the step of cooling and drying further includes an evacuation step.

49. The method of claim 46 wherein said processed products are transported for use as a fuel or fertilizer.

50. A method for treating diverse pulp and paper products derived from waste paper or MSW to produce a homogenous cellulosic feedstock comprising the steps of:

feeding diverse pulp and paper products into a vessel;

introducing steam into the vessel while agitating the products;

purging gases from the vessel while agitating the products;

capturing said gases and treating the gases to render any volatile organic compounds and any other air pollutants present in the gases harmless;

sealing the vessel so that the vessel is pressure tight;

saturating the products with steam at a temperature in the range of about 287°

F. to about 312°

F. and at a pressure in the range of about 40 psig to about 65 psig to expand the molecular structure of the products;

depressurizing the vessel to further enhance the molecular expansion of the products; and

discharging the processed products thereform.

51. The method of claim 50 wherein the pulp and paper products are derived from municipal solid waste.

52. The method of claim 50 wherein the method further includes the step of classifying cellulosic components of the processed products from other components.

53. The method of claim 52 wherein the step of classifying includes the step of separating the cellulosic components based on particle size.

54. The method of claim 52 wherein the step of classifying includes the step of separating the cellulosic components based on density.

55. The method of claim 52 wherein the step of classifying includes the step of separating the cellulosic components based on both particle size and density.

56. The method of claim 50 wherein the method further includes the steps of separating larger size components of the processed products and recycling the larger size components through the vessel for more processing.

57. The method of claim 50 wherein the method further includes the step of introducing the steam from the depressurized vessel into a second vessel containing diverse pulp and paper products for purging gases from the second vessel prior to full treatment of the products within the second vessel.

58. The method of claim 57 wherein the method further includes the steps of discharging processed products from each of a plurality of the vessels into a common conveyed stream, separating larger components from smaller components in the stream, and recycling the larger components through at least one of the vessels.

59. The method of claim 50 wherein the pulp and paper products have a moisture content of about 20% to about 60% by weight prior to the step of introducing steam.

60. The method of claim 50 wherein the temperature and pressure are maintained for a time sufficient for the products to be uniformly mixed and transformed into the homogenous cellulosic feedstock.

61. The method of claim 60 wherein the time is in the range of about 30 to about 60 minutes.

62. The method of claim 50 wherein the vessel includes a common opening serving as an inlet and outlet and the steps of feeding the diverse pulp and paper products into the vessel and discharging the diverse pulp and paper products from the vessel are both accomplished through the common opening.

63. The method of claim 62 wherein the vessel includes two or more internally mounted helical flights, the rotation of which agitates the pulp and paper products.

64. The method of claim 63 wherein the rotation of the helical flights in one direction causes the products to move away from the common opening.

65. The method of claim 63 wherein the rotation of the helical flights in a second direction causes the products to move toward the common opening.

66. The method of claim 63 wherein the vessel is capable of being tilted such that the common opening is positioned to not permit the products to fall out of the vessel.

67. The method of claim 63 wherein the vessel is capable of being tilted such that the common opening is positioned to permit the processed products to fall out of the vessel.

68. The method of claim 50 wherein the vessel includes a vent valve through which the gases are purged during the purging step.

69. The method of claim 50 wherein the step of depressurizing the vessel includes the step of recovering any steam remaining in the vessel.

70. The method of claim 69 wherein the step of recovering steam further includes the steps of condensing the steam and treating any condensable pollutants to render them harmless.

71. The method of claim 69 wherein the step of recovering the steam includes the step of recycling the steam.

72. The method of claim 50 wherein the step of depressurizing the vessel includes the step of cooling and drying the processed products, and recovering any volatile organic compounds or any other air pollutants remaining in the vessel.

73. The method of claim 72 wherein the step of cooling and drying further includes an evacuation step.