U.S. patent application number 17/677200 was filed with the patent office on 2022-08-25 for method for manufacturing bleached pulp, feedstock, and packaging system.
The applicant listed for this patent is WestRock MWV, LLC. Invention is credited to John D. DeJarnette, Yao P. Ntifafa, Fritz G. Paulsen, Maria H. Szajda-Lam.
Application Number | 20220267957 17/677200 |
Document ID | / |
Family ID | 1000006224110 |
Filed Date | 2022-08-25 |
United States Patent
Application |
20220267957 |
Kind Code |
A1 |
Paulsen; Fritz G. ; et
al. |
August 25, 2022 |
METHOD FOR MANUFACTURING BLEACHED PULP, FEEDSTOCK, AND PACKAGING
SYSTEM
Abstract
A feedstock includes feedstock paper and non-paper material. The
feedstock paper includes lignin and cellulose. A method includes
cooking the feedstock in cooking liquor to dissolve at least a
portion of the lignin from the feedstock paper and to at least
partially dissolve the non-paper material in the cooking liquor,
thereby yielding a cooked pulp. The method further includes washing
the cooked pulp to yield washed pulp and spent cooking liquor,
regenerating the spent cooking liquor to yield regenerated cooking
liquor, and bleaching the washed pulp.
Inventors: |
Paulsen; Fritz G.;
(Summerville, SC) ; Ntifafa; Yao P.; (Henrico,
VA) ; DeJarnette; John D.; (Henrico, VA) ;
Szajda-Lam; Maria H.; (Moseley, VA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
WestRock MWV, LLC |
Atlanta |
GA |
US |
|
|
Family ID: |
1000006224110 |
Appl. No.: |
17/677200 |
Filed: |
February 22, 2022 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
63151981 |
Feb 22, 2021 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
D21C 9/1084 20130101;
D21C 9/163 20130101; D21C 9/144 20130101; D21C 9/1042 20130101;
D21C 9/1036 20130101 |
International
Class: |
D21C 9/14 20060101
D21C009/14; D21C 9/10 20060101 D21C009/10 |
Claims
1. A method for manufacturing bleached pulp from a feedstock
comprising feedstock paper and non-paper material, the feedstock
paper comprising lignin and cellulose, the method comprising:
cooking the feedstock in a cooking liquor to dissolve at least a
portion of the lignin from the feedstock paper and to at least
partially dissolve the non-paper material in the cooking liquor,
thereby yielding a cooked pulp; washing the cooked pulp to yield
washed pulp and spent cooking liquor; regenerating the spent
cooking liquor to yield regenerated cooking liquor; and bleaching
the washed pulp.
2. (canceled)
3. The method of claim 1, wherein the feedstock paper has, on
average, a kappa number of at least 70.
4. (canceled)
5. The method of claim 1, wherein the feedstock paper has, on
average, a kappa number of at least 90.
6. (canceled)
7. The method of claim 1, wherein the feedstock paper has, on
average, a kappa number of at least 110.
8. The method of claim 1, wherein the feedstock paper has, on
average, a kappa number of at least 120.
9. The method of claim 1, wherein the feedstock paper includes OCC
materials.
10. The method of claim 1, wherein the non-paper material has a
positive gross heating value in a dissolved state within the
cooking liquor.
11. (canceled)
12. The method of claim 1, wherein the non-paper material has a
positive gross heating value in a dissolved state within the
cooking liquor of at least 0.1 kJ per gram of a solid content of
the non-paper material.
13. (canceled)
14. The method of claim 1, wherein the non-paper material has a
positive gross heating value in a dissolved state within the
cooking liquor of at least 10 kJ per gram of a solid content of the
non-paper material.
15. The method of claim 1, wherein the non-paper material comprises
organic non-paper material.
16. The method of claim 1, wherein the non-paper material comprises
inorganic non-paper material.
17. The method of claim 1, wherein the non-paper material comprises
non-paper packaging material.
18. The method of claim 1, wherein the non-paper material comprises
non-paper packaging material bonded between two opposing faces of
feedstock papers.
19. The method of claim 1, wherein the non-paper material comprises
non-paper packaging material sealing between two opposing ends of
feedstock papers.
20. The method of claim 1, wherein the non-paper material comprises
non-paper packaging material adhered to a surface of a feedstock
paper.
21. The method of claim 1, wherein the non-paper material comprises
non-paper packaging material unattached to any feedstock paper.
22. The method of claim 1, wherein the non-paper material comprises
adhesive.
23. The method of claim 1, wherein the non-paper material comprises
adhesive tape.
24-31. (canceled)
32. The method of claim 1, wherein the step of cooking the
feedstock in cooking liquor is cooking the feedstock in kraft
cooking liquor.
33. The method of claim 1, wherein the step of regenerating the
spent cooking liquor to yield regenerated cooking liquor utilizes a
positive gross heating value of the dissolved lignin and the
dissolved non-paper material.
34. The method of claim 1, whereby separation of the non-paper
material from the feedstock paper is avoided prior to the cooking
of the feedstock in cooking liquor, thereby avoiding a traditional
OCC plant to prep the fiber for cooking.
35. The method of claim 1, wherein the cooking comprises cooking
the feedstock in the cooking liquor to substantially fully dissolve
the non-paper material in the cooking liquor.
36. (canceled)
37. The method of claim 1, wherein the non-paper material is at
least 90 percent (by weight) soluble in the cooking liquor.
38-39. (canceled)
40. A feedstock for manufacturing bleached pulp, the feedstock
comprising: feedstock paper; and non-paper material intermixed with
the feedstock paper, wherein the non-paper material is capable of
at least partially dissolving in a cooking liquor.
41-72. (canceled)
73. A packaging system comprising: a corrugated package; and a
non-paper packaging material capable of at least partially
dissolving in a cooking liquor.
74-103. (canceled)
Description
PRIORITY
[0001] This application claims priority from U.S. Ser. No.
63/151,981 filed on Feb. 22, 2021, the entire contents of which are
incorporated herein by reference.
FIELD
[0002] The present application relates to the manufacture of pulp
from feedstock paper, and, in particular, manufacturing pulp from
OCC materials.
BACKGROUND
[0003] A substantial portion of bleached pulp is manufactured by
bleaching of virgin pulp obtained by chemical pulping of wood
chips. Bleached chemical pulp is used to manufacture various paper
products, which are used in a wide variety of applications. For
example, paperboard manufactured from bleached chemical pulp is
commonly used for various packaging applications, such as packaging
for food (e.g., cartons) and packaging for beverages (e.g., cups).
There is a growing interest in bleached paper products manufactured
from recycled pulp. Recycled pulp suitable for manufacturing of
bleached paper products may be obtained from repulping of bleached
paper products.
[0004] Recycled pulp is recovered from unbleached paper products or
mixtures of bleached or unbleached paper products, such as old
corrugated containers (OCC) materials. Traditionally, OCC materials
are delivered to paper processors where they are processed using
traditional OCC recycling processes to yield free fibers, which are
processed into different paper products such as recycled
paperboard, the center fluting of corrugated boxes, and as
unbleached kraft paperboard. The continued growth of e-commerce has
resulted in more home deliveries in corrugated containers, and,
thus, increased generation of OCC materials.
[0005] Traditional recycling of OCC materials is straightforward if
non-paper material is removed from the OCC materials prior to
collection. If not, then traditional recycling of OCC materials
requires screening and removal of non-paper material prior to the
traditional OCC recycling processes. The screening and removal of
non-paper material increases the difficulty of traditional OCC
recycling. Meanwhile, the removed non-paper material is often
burned or landfilled.
[0006] With industry sustainability goals moving towards the
circular economy, there is a desire to deliver more complete
recyclability of OCC materials and an upcycled purpose for the pulp
recovered from OCC materials.
[0007] Accordingly, those skilled in the art continue with research
and development in the field of manufacturing pulp from paper
products, and, in particular, manufacturing pulp from OCC
materials.
SUMMARY
[0008] In one embodiment, a method for manufacturing bleached pulp
from a feedstock including feedstock paper and non-paper material,
in which the feedstock paper includes lignin and cellulose,
includes: cooking the feedstock in cooking liquor to dissolve at
least a portion of the lignin from the feedstock paper and to at
least partially dissolve the non-paper material in the cooking
liquor, thereby yielding a cooked pulp; washing the cooked pulp to
yield washed pulp and spent cooking liquor; regenerating the spent
cooking liquor to yield regenerated cooking liquor; and bleaching
the washed pulp.
[0009] In another embodiment, a method for manufacturing bleached
pulp from a feedstock including feedstock paper and non-paper
material, in which the feedstock paper includes lignin and
cellulose, includes: cooking the feedstock in cooking liquor to
dissolve at least a portion of the lignin from the feedstock paper
and to substantially fully dissolve the non-paper material in the
cooking liquor, thereby yielding a cooked pulp; washing the cooked
pulp to yield washed pulp and spent cooking liquor; regenerating
the spent cooking liquor to yield regenerated cooking liquor; and
bleaching the washed pulp.
[0010] In another embodiment, a feedstock for manufacturing
bleached pulp includes feedstock paper and non-paper material
intermixed with the feedstock paper. The non-paper material is
capable of dissolving, at least partially, in a cooking liquor.
[0011] In another embodiment, a feedstock for manufacturing
bleached pulp includes feedstock paper and non-paper material
intermixed with the feedstock paper. The non-paper material is
capable of substantially fully dissolving in a cooking liquor.
[0012] In another embodiment, a packaging system includes a
corrugated package and a non-paper packaging material capable of
dissolving, at least partially, in a cooking liquor.
[0013] In yet another embodiment, a packaging system includes a
corrugated package and a non-paper packaging material capable of
substantially fully dissolving in a cooking liquor.
[0014] Other embodiments of the disclosed methods, feedstock, and
packaging systems will become apparent from the following detailed
description, the accompanying drawings and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is an exemplary method of manufacturing of
manufacturing bleached pulp according to an aspect of the present
description.
[0016] FIG. 2 is a schematic illustration of a packaging system
according to an aspect of the present description, in an unsealed
state.
[0017] FIG. 3 is a schematic illustration of the packaging system
of FIG. 2 in a sealed state.
DETAILED DESCRIPTION
[0018] A recent solution has been found to provide an economical
process for converting feedstock paper, and, in particular, OCC
materials, to bleached recycled pulp. However, the reality of
current OCC materials is that the OCC materials typically contain
non-paper material. The presence of non-paper material creates
challenges with regards to separation of the non-paper material
prior to the conversion process. The feedstock of the present
description can bypass the traditional OCC plant and go straight to
the pulping process to recover bleachable fiber. Thus, by selecting
the right materials for the feedstock, and a packaging system to be
eventually used as feedstock, the present description can avoid
large investments in OCC separation technology.
[0019] FIG. 1 is an exemplary method of manufacturing of
manufacturing bleached pulp according to an aspect of the present
description.
[0020] The present disclosure relates to a novel feedstock 10
comprising feedstock paper 11 and non-paper material 12 intermixed
with the feedstock paper 11, wherein the non-paper material 12 is
capable of dissolving, at least partially, if not substantially
fully, in a cooking liquor. As used herein, the term "paper" refers
to any material formed from pressed/laid fibers of cellulosic pulp
and includes paperboard.
[0021] The feedstock paper 11 includes lignin 13 and cellulose 14.
The feedstock paper 11 may have a relatively high quantity of
lignin 13. In one expression, a feedstock paper 11 useful in the
disclosed methods may have, on average, a kappa number of at least
60. In another expression, a feedstock paper 11 useful in the
disclosed methods may have, on average, a kappa number of at least
70. In another expression, a feedstock paper 11 useful in the
disclosed methods may have, on average, a kappa number of at least
80. In another expression, a feedstock paper 11 useful in the
disclosed methods may have, on average, a kappa number of at least
90. In yet another expression, a feedstock paper 11 useful in the
disclosed methods may have, on average, a kappa number of at least
100. In yet another expression, a feedstock paper 11 useful in the
disclosed methods may have, on average, a kappa number of at least
110. In yet another expression, a feedstock paper 11 useful in the
disclosed methods may have, on average, a kappa number of at least
120.
[0022] The non-paper material 12 includes any non-paper material 12
capable of dissolving, at least partially, in a cooking liquor,
which is a chemical solution employed to reduce wood chips (or, in
the case of the present disclosure, feedstock paper) into cellulose
fiber by dissolving lignin. In one particular implementation, the
cooking liquor may be a kraft cooking liquor, and may include
sodium hydroxide (NaOH) and sodium sulfide (Na.sub.2S) among other
possible components. In other particular implementations, the
cooking liquor may use other types of cooking chemistries (soda,
sulfite, green liquor, and carbonate).
[0023] In one expression, the non-paper material 12 is capable of
substantially fully dissolving in the cooking liquor. For example,
the non-paper material 12 may be about 100 percent soluble in the
cooking liquor.
[0024] In another expression, the non-paper material 12 at least
partially dissolves in the cooking liquor. In one example, the
non-paper material 12 may be at least 50 percent (by weight)
soluble in the cooking liquor. In another example, the non-paper
material 12 may be at least 60 percent (by weight) soluble in the
cooking liquor. In another example, the non-paper material 12 may
be at least 70 percent (by weight) soluble in the cooking liquor.
In another example, the non-paper material 12 may be at least 80
percent (by weight) soluble in the cooking liquor. In another
example, the non-paper material 12 may be at least 85 percent (by
weight) soluble in the cooking liquor. In another example, the
non-paper material 12 may be at least 90 percent (by weight)
soluble in the cooking liquor. In another example, the non-paper
material 12 may be at least 95 percent (by weight) soluble in the
cooking liquor. In yet another example, the non-paper material 12
may be at least 98 percent (by weight) soluble in the cooking
liquor.
[0025] In an aspect, the non-paper material 12 has a positive gross
heating value in the dissolved state when dissolved within the
cooking liquor. By having a positive heating value in the dissolved
state when dissolved within the cooking liquor, the non-paper
material 12 contributes to a regeneration process for regenerating
a spent cooking liquor 30 to yield regenerated cooking liquor 20
using the positive heating value of the non-paper material 12. The
heating value in the dissolved state may be determined by comparing
a heating value of a spent cooking liquor 20 with the dissolved
non-paper material 12 with a heating value of a spent cooking
liquor 20 without the dissolved non-paper material 12. If the
heating value of the spent cooking liquor 20 with the dissolved
non-paper material 12 is greater than the heating value of a spent
cooking liquor 20 without the dissolved non-paper material 12, then
the non-paper material 12 has a positive gross heating value in the
dissolved state when dissolved within the cooking liquor. In one
particular implementation, the non-paper material 12 has a high
positive gross heating value in the dissolved state when dissolved
within the cooking liquor. As one example, the non-paper material
12 may increase the heating value of the spent cooking liquor by at
least 0.01 kJ per gram of the solid content of the non-paper
material 12. In another example, the non-paper material 12 may
increase the heating value of the spent cooking liquor by at least
0.1 kJ/g.
[0026] In yet another implementation, the non-paper material 12 may
increase the heating value of the spent cooking liquor by at least
1 kJ/g. In yet another implementation, the non-paper material 12
may increase the heating value of the spent cooking liquor by at
least 10 kJ/g.
[0027] Exemplary suitable non-paper material 12 capable of
dissolving, at least partially, in the cooking liquor includes
organic or inorganic non-paper material 12 capable of dissolving in
the cooking liquor. Suitable non-paper material 12 may include, for
example, acrylic, ethylene vinyl acetate, epoxy resins, fiberglass,
isocyanate, isoprene, polyethylene glycol, polyethylene oxide,
polyvinyl acetate, polyvinyl chloride, propionates, silicone,
starch, stearic acid monoglycerides, and styrene acrylic.
[0028] In one particular implementation, the non-paper material 12
capable of dissolving, at least partially, in the cooking liquor
may be a bio-based non-paper material. Bio-based materials are
materials composed in whole or in significant part of biological
products. Suitable bio-based non-paper material 12 may include, for
example, starch.
[0029] The non-paper material 12 may take the form of various
contaminants within the feedstock paper 11. In an aspect, the
non-paper material 12 capable of dissolving, at least partially, in
the cooking liquor may take the form of packaging material, such as
adhesive, adhesive tapes, air pillows, bubble wrap, cold packs,
packaging foam, packaging peanuts, plastic wrap, printing labels,
RFID tags, or any other material employed in the packaging of a
product for shipping. The non-paper material 12 may serve a variety
of functions. The non-paper material 12 capable of dissolving, at
least partially, in the cooking liquor may include paper material
that does not dissolve in the cooking liquor.
[0030] First exemplary non-paper material 12 in the form of
packaging material may serve the function of bonding a package
together. The non-paper material 12 in the form of packaging
material may be bonded between two opposing faces of feedstock
papers. In an example, first exemplary non-paper material in the
form of packaging material may include adhesive capable of
dissolving, at least partially, in the cooking liquor. In another
example, first exemplary non-paper material in the form of
packaging material may include adhesive tapes (e.g., standard or
fiber-reinforced) capable of dissolving, at least partially, in the
cooking liquor.
[0031] Second exemplary non-paper material 12 may serve the
function of sealing a package. The non-paper material 12 in the
form of packaging material may be sealing between two opposing ends
of feedstock papers. In an example, second exemplary non-paper
material 12 in the form of packaging material may include adhesive
tapes (e.g., standard or fiber-reinforced) capable of dissolving,
at least partially, in the cooking liquor.
[0032] Third exemplary non-paper material 12 in the form of
packaging material may serve the function of adhering to the
outside or inside the package, such as for identification purposes.
The non-paper material 12 in the form of packaging material may be
adhered to a surface of a feedstock paper. In an example, third
exemplary non-paper material 12 in the form of packaging material
may include printing labels capable of dissolving, at least
partially, in the cooking liquor. In another example, third
exemplary non-paper material 12 in the form of packaging material
may include RFID tags capable of dissolving, at least partially, in
the cooking liquor.
[0033] Fourth exemplary non-paper material 12 in the form of
packaging material may serve the function of protecting a product
contained within the package. The non-paper material 12 in the form
of packaging material may be unattached to any feedstock paper. In
an example, fourth exemplary non-paper material 12 in the form of
packaging material may include air pillows capable of dissolving,
at least partially, in the cooking liquor. In another example,
fourth exemplary non-paper material 12 in the form of packaging
material may include cold packs capable of dissolving, at least
partially, in the cooking liquor. In yet another example, fourth
exemplary non-paper material 12 in the form of packaging material
may include packaging foam capable of dissolving, at least
partially, in the cooking liquor. In yet another example, fourth
exemplary non-paper material 12 in the form of packaging material
may include packaging peanuts capable of dissolving, at least
partially, in the cooking liquor. In yet another example, fourth
exemplary non-paper material 12 in the form of packaging material
may include plastic wrap capable of dissolving, at least partially,
in the cooking liquor.
[0034] For example, in the case of a feedstock paper 11 that is (or
includes) OCC materials, the feedstock paper 11 may contain various
contaminates, such as adhesive, adhesive tapes (e.g., standard or
fiber-reinforced), air pillows, bubble wrap, cold packs, packaging
foam, packaging peanuts, plastic wrap, printing labels, RFID tags,
and other non-paper packaging materials. In the feedstock 10 of the
present disclosure, non-paper material 12 (e.g., contaminants) is
formed from non-paper material 12 capable of dissolving, at least
partially, in the cooking liquor. Thus, because the non-paper
material 12 included with the feedstock paper 11 is capable of
dissolving, at least partially, in the cooking liquor, the
feedstock 10 of the present disclosure may be utilized in the
methods of the present disclosure without necessitating separation
of non-paper material 12 prior to conversion of the feedstock paper
11 into bleached recycled pulp.
[0035] The non-paper material 12 capable of dissolving, at least
partially, in the cooking liquor may include paper material that
does not dissolve in the cooking liquor, but the paper material
within the non-paper material 12 may be repulped with the feedstock
papers. In an example, a fiber-reinforced adhesive tapes may
include cellulosic fibers that reinforce the adhesive tape. The
cellulosic fibers may not dissolve in the cooking liquor. However,
the cellulosic fibers may be pulped to manufacture the recycled
bleached pulp. In another example, a printing label may include
paper material and non-paper material 12 capable of dissolving, at
least partially, in the cooking liquor. The paper material may not
dissolve in the cooking liquor. However, the paper material may be
pulped to manufacture the recycled bleached pulp.
[0036] The feedstock 10 of the present disclosure excludes
substantial amounts of other solid materials that do not dissolve
in the cooking liquor. In one implementation, at least 90 weight
percent of the solids content of the feedstock 10 is the feedstock
paper 11 and the non-paper material 12. In another implementation,
at least 95 weight percent of the solids content of the feedstock
10 is the feedstock paper 11 and the non-paper material 12. In yet
another implementation, at least 98 weight percent of the solids
content of the feedstock 10 is the feedstock paper 11 and the
non-paper material 12. In yet another implementation, at least 99
weight percent of the solids content of the feedstock 10 is the
feedstock paper 11 and the non-paper material 12. In yet another
implementation, at least 99.5 weight percent of the solids content
of the feedstock 10 is the feedstock paper 11 and the non-paper
material 12. In yet another implementation, at least 99.8 weight
percent of the solids content of the feedstock 10 is the feedstock
paper 11 and the non-paper material 12. In yet another
implementation, at least 99.9 weight percent of the solids content
of the feedstock 10 is the feedstock paper 11 and the non-paper
material 12. By limiting the amounts of solid materials that do not
dissolve in the cooking liquor, separation of the non-dissolved
solid materials can be minimized or avoided.
[0037] The feedstock 10 may contain water. The quantity of water in
the feedstock may be due to the equilibrium moisture content or may
be greater than the equilibrium moisture content. In one
expression, the feedstock may have a solids content of at least 70
percent by weight. In another expression, the feedstock may have a
solids content of at least 75 percent by weight. In another
expression, the feedstock may have a solids content of at least 80
percent by weight. In another expression, the feedstock may have a
solids content of at least 85 percent by weight. In another
expression, the feedstock may have a solids content of at least 90
percent by weight. In yet another expression, the feedstock may
have a solids content of at least 95 percent by weight.
[0038] The feedstock 10 may be in the form of a bundle of feedstock
paper 11 and non-paper material 12 pressed together into a
densified mass. Various types of feedstock paper 11 may be used
without departing from the scope of the present disclosure. In one
specific example, a suitable feedstock paper 11 may be (or may
include) old corrugated containers (OCC), which may be received in
bulk (e.g., bales). An OCC bale is a bundle of old corrugated
containers that have been pressed together at a high pressure into
densified mass. A typical bale size may be, for example, in a range
of from 5 to 100 cubic feet, such as in a range of from 10 to 50
cubic feet. Those skilled in the art will appreciate that a
feedstock comprised of a mixture of different types of feedstock
paper 11 may be used. Other non-limiting examples of suitable
feedstock for the disclosed methods include corrugated box plant
clippings, kraft bagging, newsprint, and recovered kraft fibers,
double liner kraft (DLK), and paper mill broke (trim rolls or
rejected quality rolls).
[0039] Illustrated in FIG. 1 is an example of the methods of the
present disclosure, generally designated 100, for manufacturing
bleached pulp 50 from a feedstock 10 comprising at least feedstock
paper 11 and non-paper material 12.
[0040] At Block 110, the method 100 may include a step of reducing
a size of the feedstock 10. The size reduction step (Block 110) may
be performed before an impregnation step (Block 120), though
variations are contemplated and will not result in a departure from
the scope of the present disclosure.
[0041] Various techniques may be used for reducing the size of
(e.g., shredding) the feedstock 10. As one non-limiting example, a
hogger may be used to perform the size reduction step (Block 110).
As another non-limiting example, a cutter may be used to perform
the size reduction step (Block 110). As yet another non-limiting
example, a slicer may be used to perform the size reduction step
(Block 110).
[0042] At Block 120, the method 100 may include a step of
impregnating the feedstock 10 with cooking liquor 20 prior to a
cooking step (Block 130). In one particular implementation, the
cooking liquor 20 may be a kraft cooking liquor, and may include
sodium hydroxide (NaOH) and sodium sulfide (Na.sub.2S) among other
possible components. In other particular implementations, the
cooking liquor 20 may use other types of cooking chemistries (soda,
sulfite, green liquor, and carbonate).
[0043] The impregnation step (Block 120) may yield an impregnated
material 22 having a liquor-to-fiber mass ratio. In one expression,
the liquor-to-fiber mass ratio may be at most about 4:1. In another
expression, the liquor-to-fiber mass ratio may be at most about
3:1. In another expression, the liquor-to-fiber mass ratio may be
less than 3:1. In another expression, the liquor-to-fiber mass
ratio may be at most about 2.5:1. In another expression, the
liquor-to-fiber mass ratio may be at most about 2:1. In yet another
expression, the liquor-to-fiber mass ratio may range from about 1:1
to about 3:1. Because of the relatively low liquor-to-fiber mass
ratio of the impregnated material 22, those skilled in the art will
appreciate that the subsequent cooking step (Block 130) may be
referred to as vapor-phase digestion. However, the present
disclosure is not limited to a low liquor-to-fiber mass ratio or to
vapor-phase digestion.
[0044] The cooking liquor 20 used in the impregnation step (Block
120) may contain a percentage of active alkali ions. In one
expression, the percentage of active alkali ions may be about 5
percent by weight of the feedstock 10 to about 10 percent by weight
of the feedstock 10. In another expression, the percentage of
active alkali ions may be about 5 percent by weight of the
feedstock to about 15 percent by weight of the feedstock. In
another expression, the percentage of active alkali ions may be
about 5 percent by weight of the feedstock to about 20 percent by
weight of the feedstock. In yet another expression, the percentage
of active alkali ions may be about 5 percent by weight of the
feedstock to about 25 percent by weight of the feedstock.
[0045] As shown in Block 122, the impregnation step (Block 120) may
include the step of compressing the feedstock 10. Without being
limited to any particular theory, it is believed that compressing
the feedstock 10 aids in the impregnation step (Block 120) and
facilitates a more uniform distribution of the cooking liquor 20
throughout the impregnated material 22.
[0046] Various techniques may be used to perform the compressing
step (Block 122). As one specific, non-limiting example, the
compressing step (Block 122) may be performed by a plug/compression
screw feeder, such as an MSD Impressafiner.RTM., which is
commercially available from Andritz AG of Graz, Austria. As another
non-limiting example, the compressing step (Block 122) may be
performed by a screw press. As yet another non-limiting example,
the compressing step (Block 122) may be performed by a kneader. The
use of multiple different apparatus (e.g., in series and/or in
parallel) for performing the compressing step (Block 122) is also
contemplated.
[0047] The compressing step (Block 122) may be performed on the
feedstock 10 to achieve a desired compression ratio. In one
expression, the compressing step (Block 122) may be performed to
achieve a compression ratio greater than 1:1, on a volume basis. In
another expression, the compressing step (Block 122) may be
performed to achieve a compression ratio of at least about 1.5:1,
on a volume basis. In another expression, the compressing step
(Block 122) may be performed to achieve a compression ratio of at
least about 2:1, on a volume basis. In another expression, the
compressing step (Block 122) may be performed to achieve a
compression ratio of at least about 2.5:1, on a volume basis. In
another expression, the compressing step (Block 122) may be
performed to achieve a compression ratio of at least about 3:1, on
a volume basis. In another expression, the compressing step (Block
122) may be performed to achieve a compression ratio of at least
about 3.5:1, on a volume basis. In another expression, the
compressing step (Block 122) may be performed to achieve a
compression ratio of at least about 4:1, on a volume basis. In yet
another expression, the compressing step (Block 122) may be
performed to achieve a compression ratio between about 2:1 and
about 4:1, on a volume basis.
[0048] As shown in Block 124, the impregnation step (Block 120) may
further include the step of adding a surfactant to the feedstock
10. Without being limited to any particular theory, the addition of
surfactant may aid in the penetration of cooking liquor 20 into
materials.
[0049] At Block 130, the method 100 includes the step of cooking
the impregnated material 22 to dissolve lignin 13 from the
feedstock paper 11 and to dissolve, at least partially, the
non-paper material 12 into the cooking liquor 20, thereby yielding
a cooked pulp 24. The cooking step (Block 130) may be performed in
a continuous digester, such as a Pandia-type digester, a Messig
& Durkee (M&D-type) digester, a Kamyr-type digester, or the
like. However, the use of a batch digester (or both a batch
digester and a continuous digester) is also contemplated.
[0050] The cooking step (Block 130) dissolves lignin 13 from the
feedstock paper 11 into the cooking liquor 20. In one expression,
the cooking step (Block 130) may be performed to a kappa number of
at most about 40. In another expression, the cooking step (Block
130) may be performed to a kappa number of at most about 35. In
another expression, the cooking step (Block 130) may be performed
to a kappa number of at most about 33. In another expression, the
cooking step (Block 130) may be performed to a kappa number of at
most about 30. In yet another expression, the cooking step (Block
130) may be performed to a kappa number ranging from about 15 to
about 40. In yet another expression, the cooking step (Block 130)
may be performed to a kappa number ranging from about 24 to about
32.
[0051] The cooking step (Block 130) may be performed at a cooking
temperature and the impregnated material 22 may have a residence
time at the cooking temperature. Those skilled in the art will
appreciate that the cooking temperature and the residence time may
depend on various factors, such as the chemistry of the cooking
liquor 20 and the liquor-to-fiber mass ratio of the impregnated
material 22. For example, when the cooking liquor 20 is a kraft
cooking liquor, the cooking temperature may range from about
140.degree. C. and about 170.degree. C., and the residence time may
range from about 30 minutes to about 90 minutes at the cooking
temperature.
[0052] During the step of cooking the impregnated material 22, the
non-paper material 12 dissolve, at least partially, into the
cooking liquor 20 at the same conditions during which the cooking
step dissolves lignin 13 from the feedstock paper 11 into the
cooking liquor 20. In one implementation, the non-paper material 12
dissolves into the cooking liquor 20 more easily than the lignin 13
from the feedstock paper 11 so that the non-paper material 12 is
fully dissolved when the desired amount of lignin is removed from
the feedstock paper 11.
[0053] At Block 135, the method 100 may include the step of
screening the cooked pulp 24 to remove rejects 136. For example,
the rejects 136 may include undissolved material 137, such as
undissolved non-paper material 12. At this point, those skilled in
the art will appreciate that the screening step 135 may only be
required when the non-paper material 12 is not fully (about 100
percent) soluble in the cooking liquor 20.
[0054] At Block 140, the method 100 includes the step of washing
the cooked pulp 24 to yield washed pulp 26 and spent cooking liquor
30. The washing step (Block 140) may be performed, for example,
with water or an aqueous solution, as is well known in the art.
[0055] At Block 150, the spent cooking liquor 30 is regenerated to
yield regenerated cooking liquor 20 using a positive heating value
of the dissolved lignin and the dissolved non-cellulosic organic
components in the spent cooking liquor 30. The regeneration step,
block 150, is not limited and may include any method for
regenerating a spent cooking liquor 30. For example, the step of
regenerating the spent cooking liquor 30 may include, for example,
an evaporation step at block 152 and a recovery step at block
154.
[0056] At Block 160, the method 100 may optionally include the step
of blending the cooked pulp 24 (or washed pulp 26, if washed first)
with virgin pulp 40 (i.e., pulp not obtained by recycling) to yield
a pulp blend 42. The blending step (Block 160) may be performed
prior to the bleaching step (Block 170), though variations (e.g.,
blending after bleaching) are also contemplated.
[0057] The pulp blend 42 may contain various quantities of virgin
pulp 40 without departing from the scope of the present disclosure.
In one non-limiting example, the pulp blend 42 includes about 5
percent by weight to about 95 percent by weight cooked pulp 24 (or
washed pulp 26, if washed first), with balance virgin pulp 40. In
another non-limiting example, the pulp blend 42 includes about 5
percent by weight to about 85 percent by weight cooked pulp 24 (or
washed pulp 26, if washed first), with balance virgin pulp 40. In
another non-limiting example, the pulp blend 42 includes about 5
percent by weight to about 75 percent by weight cooked pulp 24 (or
washed pulp 26, if washed first), with balance virgin pulp 40. In
another non-limiting example, the pulp blend 42 includes about 5
percent by weight to about 65 percent by weight cooked pulp 24 (or
washed pulp 26, if washed first), with balance virgin pulp 40. In
another non-limiting example, the pulp blend 42 includes about 5
percent by weight to about 50 percent by weight cooked pulp 24 (or
washed pulp 26, if washed first), with balance virgin pulp 40. In
yet another non-limiting example, the pulp blend 42 includes about
10 percent by weight to about 30 percent by weight cooked pulp 24
(or washed pulp 26, if washed first), with balance virgin pulp
40.
[0058] At Block 170, the method 100 includes the step of bleaching
the cooked pulp 24 (or the washed pulp 26, if washed, or the pulp
blend 42, if blended) to yield bleached pulp 50. The bleaching step
(Block 170) increases the brightness of the pulp. In one
expression, the bleaching step (Block 170) is performed to achieve
a GE brightness of at least about 70 percent. In another
expression, the bleaching step (Block 170) is performed to achieve
a GE brightness of at least about 75 percent. In another
expression, the bleaching step (Block 170) is performed to achieve
a GE brightness of at least about 80 percent. In another
expression, the bleaching step (Block 170) is performed to achieve
a GE brightness of at least about 85 percent. In yet another
expression, the bleaching step (Block 170) is performed to achieve
a GE brightness of at least about 90 percent.
[0059] Various bleaching techniques may be used for the bleaching
step (Block 170). As one non-limiting example, the bleaching step
(Block 170) includes traditional chlorine bleaching. As another
non-limiting example, the bleaching step (Block 170) includes
chlorine dioxide bleaching. As another non-limiting example, the
bleaching step (Block 170) includes peroxide bleaching. As another
non-limiting example, the bleaching step (Block 170) includes
oxygen bleaching.
[0060] At Block 180, the method 100 may include the step of storing
the bleached pulp 50 in a storage vessel. For example, the storing
step (Block 180) may include storing the bleached pulp in a
high-density storage tank. After storing (or as an alternative to
storing), the bleached pulp 50 may be used to manufacture various
articles (e.g., paperboard; cups containing paperboard; etc.).
Accordingly, the method 100 produces recycled bleached pulp 50,
which may be used in a variety of applications, such as for
manufacturing paper, including paperboard.
[0061] FIG. 2 is a schematic illustration of a packaging system
according to an aspect of the present description, in an unsealed
state. FIG. 3 is a schematic illustration of the packaging system
of FIG. 2 in a sealed state.
[0062] The present disclosure relates to a novel packaging system
60 having improved sustainability. The packaging system 60
comprises a corrugated package 70 and a non-paper packaging
material 80 capable of dissolving, at least partially, in a cooking
liquor, which is a chemical solution employed to reduce wood chips
(or, in the case of the present disclosure, feedstock paper) into
cellulose fiber by dissolving lignin. In one particular
implementation, the cooking liquor may be a kraft cooking liquor,
and may include sodium hydroxide (NaOH) and sodium sulfide
(Na.sub.2S) among other possible components. In other particular
implementations, the cooking liquor may use other types of cooking
chemistries (soda, sulfite, green liquor, and carbonate).
[0063] The corrugated package 70 includes a plurality of corrugated
walls 71 defining an opening 72 for placing or removing a product
90 therein. The opening 72 is in the unsealed state before placing
the product 90 in the corrugated package 70. The opening 72 is in
the sealed state after to placing the product 90 in the corrugated
package 70 and during transportation of the corrugated package 70
to a destination. The opening 72 is in the unsealed state after
removing the product 90 from the corrugated package 70. The form of
the corrugated package 70 is not limited and may include, for
example, a corrugated box formed from a single blank of corrugated
paperboard, in which corrugated walls 71 are formed by folding the
corrugated paperboard, and in which at least one of the walls
includes overlapping portions of paperboard, between which are
positioned an adhesive or adhesive tape.
[0064] The non-paper packaging material 80 capable of dissolving,
at least partially, in a cooking liquor may serve a variety of
functions with regards to the corrugated package 70.
[0065] A first exemplary non-paper packaging material 80 may serve
the function of bonding the corrugated package 70 together. The
first exemplary non-paper packaging material may be bonded between
two opposing faces of the corrugated package. For example, the
first exemplary non-paper packaging material may include adhesive
or adhesive tapes (e.g., standard or fiber-reinforced) capable of
dissolving, at least partially, in a cooking liquor.
[0066] A second exemplary non-paper packaging material may serve
the function of sealing the corrugated package 70. The non-paper
packaging material may be sealing between two opposing ends of the
corrugated package 70. For example, the second exemplary non-paper
packaging material may include adhesive or adhesive tapes (e.g.,
standard or fiber-reinforced) capable of dissolving, at least
partially, in a cooking liquor.
[0067] A third exemplary non-paper packaging material 80 may serve
the function of adhering to the outside or inside the corrugated
package 70, such as for identification purposes. The non-paper
packaging material may be adhered to a surface of a corrugated
package 70. In an example, the third exemplary non-paper packaging
material 80 may include a printing label capable of dissolving, at
least partially, in a cooking liquor adhered to the outside or
inside the corrugated package 70. In another example, the third
exemplary non-paper packaging material include RFID tag capable of
dissolving, at least partially, in a cooking liquor. The RFID tag
may be adhered to the outside or inside the corrugated package
70.
[0068] A fourth exemplary non-paper packaging material 80 may serve
the function of protecting a product 90 contained within the
corrugated package 70. The non-paper packaging material 80 may be
unattached to any feedstock paper. For example, the fourth
exemplary non-paper packaging material include non-paper packaging
material capable of dissolving, at least partially, in a cooking
liquor contained within the corrugated package 70, such as air
pillows capable of dissolving, at least partially, in a cooking
liquor, bubble wrap capable of dissolving, at least partially, in a
cooking liquor, cold packs capable of dissolving, at least
partially, in a cooking liquor, packaging foam capable of
dissolving, at least partially, in a cooking liquor, packaging
peanuts capable of dissolving, at least partially, in a cooking
liquor, and plastic wrap capable of dissolving, at least partially,
in a cooking liquor. In another example, the fourth exemplary
non-paper packaging material may include a paper packing material
contained within the corrugated package 70, to which an adhesive or
adhesive tapes (e.g., standard or fiber-reinforced) is adhered
thereto, in which the adhesive or adhesive tape is capable of
dissolving, at least partially, in a cooking liquor.
[0069] The corrugated package 70 includes lignin and cellulose. The
corrugated package 70 may have a relatively high quantity of
lignin. In one expression, the corrugated package 70 may have a
kappa number of at least 60. In another expression, the corrugated
package 70 useful in the disclosed methods may have a kappa number
of at least 70. In another expression, the corrugated package 70
useful in the disclosed methods may have a kappa number of at least
80. In another expression, the corrugated package 70 useful in the
disclosed methods may have a kappa number of at least 90. In yet
another expression, the corrugated package 70 useful in the
disclosed methods may have a kappa number of at least 100. In yet
another expression, the corrugated package 70 useful in the
disclosed methods may have a kappa number of at least 110. In yet
another expression, the corrugated package 70 useful in the
disclosed methods may have a kappa number of at least 120.
[0070] The non-paper packaging material 80 include any non-paper
material capable of dissolving, at least partially, in a cooking
liquor, which is a chemical solution employed to reduce wood chips
(or, in the case of the present disclosure, feedstock paper) into
cellulose fiber by dissolving lignin. In one particular
implementation, the cooking liquor may be a kraft cooking liquor,
and may include sodium hydroxide (NaOH) and sodium sulfide
(Na.sub.2S) among other possible components. In other particular
implementations, the cooking liquor may use other types of cooking
chemistries (soda, sulfite, green liquor, and carbonate).
[0071] In one particular aspect, the non-paper packaging material
80 have a positive gross heating value in the dissolved state when
dissolved within the cooking liquor. By having a positive heating
value in the dissolved state when dissolved within the cooking
liquor, the non-paper packaging material 80 contribute to a
regeneration process for regenerating a spent cooking liquor to
yield regenerated cooking liquor using the positive heating value
of the non-paper packaging material 80. The heating value in the
dissolved state may be determined by comparing a heating value of a
spent cooking liquor with the dissolved non-paper packaging
material 80 with a heating value of a spent cooking liquor without
the dissolved non-paper packaging material 80. If the heating value
of the spent cooking liquor with the dissolved non-paper packaging
material 80 is greater than the heating value of a spent cooking
liquor without the dissolved non-paper packaging material 80, then
the non-paper packaging material 80 has a positive gross heating
value in the dissolved state when dissolved within the cooking
liquor. In one implementation, the non-paper packaging material 80
has a high positive gross heating value in the dissolved state when
dissolved within the cooking liquor. In one example, the non-paper
packaging material 80 may increase the heating value of the spent
cooking liquor by at least 0.01 kJ per gram of the solid content of
the non-paper packaging material 80. In another example, the
non-paper packaging material 80 may increase the heating value of
the spent cooking liquor by at least 0.1 kJ/g. In another example,
the non-paper packaging material 80 may increase the heating value
of the spent cooking liquor by at least 1 kJ/g. In yet another
example, the non-paper packaging material 80 may increase the
heating value of the spent cooking liquor by at least 10 kJ/g.
[0072] Exemplary suitable non-paper packaging material 80 include
organic or inorganic non-paper material 12 capable of dissolving,
at least partially, in the cooking liquor. Suitable non-paper
material may include, for example, acrylic, ethylene vinyl acetate,
epoxy resins, fiberglass, isocyanate, isoprene, polyethylene
glycol, polyethylene oxide, polyvinyl acetate, polyvinyl chloride,
propionates, silicone, starch, stearic acid monoglycerides, and
styrene acrylic.
[0073] In one particular implementation, the non-paper packaging
material 80 capable of dissolving, at least partially, in the
cooking liquor may be a bio-based non-paper material. Bio-based
materials are materials comprises in whole or significant part of
biological products. Suitable bio-based non-paper material may
include, for example, starch.
[0074] The non-paper packaging material 80 may include paper
material that does not dissolve in the cooking liquor, but the
paper material within the non-paper packaging material 80 may be
repulped. In an example, a fiber-reinforced adhesive tapes may
include cellulosic fibers that reinforce the adhesive tape. The
cellulosic fibers may not dissolve in the cooking liquor. However,
the cellulosic fibers may be pulped to manufacture the recycled
bleached pulp. In another example, a printing label may include
paper material and non-paper material capable of dissolving in the
cooking liquor. The paper material may not dissolve in the cooking
liquor. However, the paper material may be repulped to manufacture
the recycled bleached pulp.
[0075] After utilization of the corrugated package 70 and the
non-paper packaging material 80, they may be utilized as feedstock
10 for the method 100 of the present description.
EXAMPLE 1
[0076] In this example two components from a novel packaging system
60 shown in FIG. 3 were separated into their individual component
forms (i.e., corrugated package 70 and a non-paper packaging
material 80) to enable measurement of the residual cooking liquor
heating values as a result of alkali digestion. Combined box board
packaging as the corrugated package 70 was collected from recycled
materials made from traditional linerboard, corrugating medium and
starch-based adhesives. The non-paper packaging material 80 was a
tape available from 3M as Product R3187. Both components were dry
shredded independently for the purpose of the experiment.
[0077] After shredding, each component listed above was digested
independently in small laboratory digester reactors at typical
kraft pulping conditions using a kraft white liquor mixture of
sodium hydroxide and sodium sulfide as the cooking liquor portrayed
as 20 in FIG. 1. An 18% alkali charge as active alkali on dry
combined board or dry tape was used at 25% sulfidity and cooked to
a temperature of 165 degrees centigrade and held at this
temperature for about 30 to 35 minutes for each cook. After the
cook time was completed, for both cooks, the digester was cooled,
and contents removed and washed in the laboratory on a Buchner
funnel with clean wash water. From FIG. 1, the remaining separated
fiber suspended solids (washed pulp 26) and spent cooking liquor 30
(with dissolved lignin 13) were separated from the Buchner funnel.
The washed pulp 26 can be further processed into unbleached paper
or subjected to further processing to produce a bleached pulp 50.
The cooking liquor 30 was further evaporated and tested for higher
heating values on a moisture free dry basis.
[0078] Table 1 demonstrates the contribution of the packaging
material before digestion, the resulting digested pulp, and
residual cooking black liquors to the higher heating value on a KJ
per oven dried gram solids basis or on a moisture free basis. The
as-is columns represent the components total higher heating value
on a bone-dry basis before digestion, while the pulp and black
liquor columns represent the two component streams after the alkali
digestion and the washing separation phase completed. Higher
heating values on a fuel solids dry basis were determined on an IKA
calorimeter C 6000 Isoperibol and the TAPPI method T684 was used to
determine the heating values of the black liquors.
[0079] Under similar cooking conditions and white liquor charges
the tape component process black liquors contributed about 7% more
KJ/g on the dry solids recovered over the recovered combined board,
7.7 KJ/g versus 7.2KJ/g. These results represent higher heating
values and include extracted lignin from the fibrous components of
each and the dry inorganic cooking liquor solids of the cooking
chemicals, and adhesives from the tape. The adhesives and
non-fibrous materials of the packing tape broke down into the
alkali cooking liquors and were successfully washed from the
residual fiber of the tape backing. For recovered pulps of Table 1
a measure of residual lignin content made by the TAPPI standard
T236 was made on the recovered fibers from both components. Kappa
number of the combined board prior to digestion was about 82.3. The
cooking process will both remove product lignin from the medium and
linerboard grades, isolate the fiber from the tape backing, and
dissolve the non-fibrous adhesive components into the process black
liquors for improved heating value.
TABLE-US-00001 TABLE 1 Recycled Corrugated Board Recovered from the
Package Tape from the Package Item 70 Item 80 Control Control Tape
Sample Control Black Tape Tape Black As-is Pulp Liquor As-is Pulp
Liquor Higher Heating 16.2 15.9 7.2 20.5 17.4 7.7 Value (KJ/g)
Kappa Number 19.30 16.70
[0080] Normal commercial operation and practice of this invention,
the components would be received post-consumer with tape and labels
still attached to the combined board package, dry shredded together
and digested together eliminating several steps of the traditional
package recycling effort. Typical non repulpable tapes would be
replaced with the alkali soluble tapes while reclaiming the
adhesives to utilize as fuel value in a traditional kraft recovery
system. After digestion, these recovered residual black residual
cooking liquors are concentrated and energy captured through
combustion, while any cellulosic components of 70 and 80 are
recovered can be used as is or further bleached and used for future
packaging. This example provides evidence that a positive gain in
process cooking liquor heating values is possible if the packaging
materials of the present description are co digested with the
combined board.
[0081] Although various embodiments of the disclosed methods,
feedstock, and packaging systems have been shown and described,
modifications may occur to those skilled in the art upon reading
the specification. The present application includes such
modifications and is limited only by the scope of the claims.
* * * * *