U.S. patent application number 11/677832 was filed with the patent office on 2007-07-05 for method and device for loading a fibrous stock suspension.
Invention is credited to KLAUS DOELLE.
Application Number | 20070151681 11/677832 |
Document ID | / |
Family ID | 34979775 |
Filed Date | 2007-07-05 |
United States Patent
Application |
20070151681 |
Kind Code |
A1 |
DOELLE; KLAUS |
July 5, 2007 |
METHOD AND DEVICE FOR LOADING A FIBROUS STOCK SUSPENSION
Abstract
The present invention relates to a method and a device for
loading a fibrous stock suspension including a plurality of
cellulose fibers with calcium carbonate. The method includes adding
calcium hydroxide in liquid or dry form and/or calcium oxide into
the fibrous stock suspension, adding carbon dioxide into the
fibrous stock suspension, and precipitating calcium carbonate from
calcium hydroxide through carbon dioxide in a pressurized
vessel.
Inventors: |
DOELLE; KLAUS; (Kisslegg,
DE) |
Correspondence
Address: |
TAYLOR & AUST, P.C.
142 SOUTH MAIN STREET
P. O. BOX 560
AVILLA
IN
46710
US
|
Family ID: |
34979775 |
Appl. No.: |
11/677832 |
Filed: |
February 22, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/EP05/08851 |
Aug 16, 2005 |
|
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11677832 |
Feb 22, 2007 |
|
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Current U.S.
Class: |
162/9 ;
162/181.2; 422/129 |
Current CPC
Class: |
D21H 21/52 20130101;
D21H 23/04 20130101; D21H 17/675 20130101; D21H 17/70 20130101 |
Class at
Publication: |
162/009 ;
162/181.2; 422/129 |
International
Class: |
D21H 23/16 20060101
D21H023/16; D21H 17/70 20060101 D21H017/70 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 17, 2004 |
DE |
10 2004 045 089.7 |
Claims
1. A method for loading a fibrous stock suspension including a
plurality of cellulose fibers with calcium carbonate, said method
comprising the steps of: adding at least one of calcium hydroxide
in one of liquid and dry form and calcium oxide into the fibrous
stock suspension; adding carbon dioxide into the fibrous stock
suspension; and precipitating calcium carbonate from said calcium
hydroxide through said carbon dioxide in a pressurized vessel.
2. The method in accordance with claim 1, further comprising the
step of supplying an aqueous fiber raw material with a consistency
of between 1 and 20% fiber stock component into said pressure
vessel.
3. The method in accordance with claim 2, wherein said aqueous
fiber raw material is an aqueous paper raw material.
4. The method in accordance with claim 2, wherein said fiber stock
component includes a low consistency fiber stock material at a
content of between 1 and 6%.
5. The method in accordance with claim 2, wherein said fiber stock
component includes a medium consistency fiber stock material at a
content of between 6 and 10%.
6. The method in accordance with claim 2, wherein said fiber stock
component includes a high consistency fiber stock material at a
content of between 10 and 20%.
7. The method in accordance with claim 2, wherein said aqueous
fiber raw material is diluted to the fibrous stock suspension
having a consistency of between 0.1 and 20%.
8. The method in accordance with claim 2, wherein said aqueous
fiber raw material is diluted to the fibrous stock suspension
having a consistency of between 2 and 18%.
9. The method in accordance with claim 1, wherein said pressure
vessel is closed by a sluice after introducing at least one of an
aqueous fiber stock material and a dilution water.
10. The method in accordance with claim 9, wherein at least one of
said calcium hydroxide and said calcium oxide is mixed into said
aqueous fiber stock material within a range of between 0.1 and 60%
of an existing solids content of a volume of a dry fiber stock.
11. The method in accordance with claim 10, wherein the method is
carried out at a pH value of between 6 and 11.
12. The method in accordance with claim 10, wherein the method is
carried out at a pH value of between 6.5 and 10.5.
13. The method in accordance with claim 10, wherein said calcium
hydroxide includes a reactivity in a range of between 0.0005 and 30
minutes.
14. The method in accordance with claim 10, wherein said calcium
hydroxide includes a reactivity in a range of between 0.05 and 10
minutes.
15. The method in accordance with claim 1, wherein said calcium
carbonate is precipitated by adding said carbon dioxide within a
pressure range of between 0 and 15 bar.
16. The method in accordance with claim 1, wherein said calcium
carbonate is precipitated by adding said carbon dioxide within a
pressure range of between 0 and 6 bar.
17. The method in accordance with claim 1, wherein at least one of
the fibrous stock suspension and said carbon dioxide is heated by
one of process water, dilution water, and steam during dissolution
in the fibrous stock suspension.
18. The method in accordance with claim 1, wherein at least one of
the fibrous stock suspension and said carbon dioxide is heated by
one of a fiber loading process and introducing heat energy from
outside.
19. The method in accordance with claim 1, wherein at least one of
the fibrous stock suspension and said carbon dioxide is heated by
one of a steam energy and an electrical energy.
20. The method in accordance with claim 1, wherein said carbon
dioxide is added one of prior to, during, and after adding one of
said carbon dioxide, said calcium hydroxide, and said calcium
oxide.
21. The method in accordance with claim 1, wherein said pressure
vessel is opened by one of a valve and a sluice one of prior to and
after a fiber loading reaction.
22. The method in accordance with claim 1, further comprising
precipitating a plurality of loaded fibers, wherein an energy
expenditure for said precipitating said plurality of loaded fibers
is between 0.3 and 8 kWh/t.
23. The method in accordance with claim 22 wherein no refiner is
used for a refining of a fiber stock.
24. The method in accordance with claim 22, further comprising the
step of refining a fiber stock inside said pressure vessel during a
precipitation process.
25. The method in accordance with claim 1, further comprising
precipitating a plurality of loaded fibers, wherein an energy
expenditure for said precipitating said plurality of loaded fibers
is between 0.5 and 4 kWh/t.
26. The method in accordance with claim 25, wherein no refiner is
used for a refining of a fiber stock.
27. The method in accordance with claim 1, wherein a process
temperature is between--15 and 120.degree. C.
28. The method in accordance with claim 1, wherein a process
temperature is between 20 and 90.degree. C.
29. The method in accordance with claim 27, wherein a plurality of
rhombohedral, scalenohedron, and spherical crystals are formed.
30. The method in accordance with claim 29, wherein said plurality
of crystals include dimensions of between 0.05 and 5 .mu.m.
31. The method in accordance with claim 29, wherein said plurality
of crystals include dimensions of between 0.3 and 2.5 .mu.m.
32. The method in accordance with claim 1, further comprising
mixing the fibrous stock suspension with at least one mixing
element including at least one of a static and a moving mixing
element.
33. The method in accordance with claim 32, wherein said at least
one mixing element includes a rotating mixing element.
34. A device for loading a fibrous stock suspension including a
plurality of cellulose fibers with calcium carbonate, said device
comprising: an infeed device for supplying a fiber raw material;
and a pressure vessel, the device configured for adding at least
one of calcium hydroxide in one of liquid and dry form and calcium
oxide into the fibrous stock suspension, adding carbon dioxide into
the fibrous stock suspension, and precipitating calcium carbonate
from said calcium hydroxide through said carbon dioxide in a
pressurized vessel.
35. The device in accordance with claim 34, wherein said pressure
vessel includes one of a sluice and a valve configured for feeding
through said fiber raw material for producing the fibrous stock
suspension with a plurality of loaded fibers.
36. The device in accordance with claim 34, wherein said pressure
vessel includes a plurality of inlets for at least one of dilution
water, press water, calcium oxide, calcium hydroxide, and carbon
dioxide.
37. The device in accordance with claim 34, wherein said pressure
vessel includes a rotor for mixing the fibrous stock suspension.
Description
BACKGROUND OF THE INVENTION
[0001] This is a continuation of PCT application No.
PCT/EP2005/008851, entitled "METHOD AND DEVICE FOR CHARGING A FIBRE
MATERIAL SUSPENSION", filed Aug. 16, 2005.
[0002] 1. Field of the Invention
[0003] The invention relates to a method for loading of a fibrous
stock suspension with calcium carbonate.
[0004] 2. Description of the Related Art
[0005] Several methods for loading chemical pulp fibers with
calcium carbonate are already known. A method is described in U.S.
Pat. No. 6,413,365 B1 where the fibrous material is transported via
a supply line together with calcium oxide and/or calcium hydroxide
which are contained in said suspension. From there, the fibrous
stock suspension is transported into a rotating distribution
device. A reaction gas is fed in a ring shaped pattern into the
fibrous stock suspension; this causes formation of calcium
carbonate crystals in the fibrous suspension. The calcium carbonate
crystals are distributed in the fibrous stock suspension through
the rotating distributor device. This process is known as Fiber
Loading Process.
[0006] A method for loading a fibrous stock suspension is known
from DE 101 07 448 A1 wherein the fibrous stock suspension is fed
into a crystallizer and is treated in said crystallizer by shear
forces in order to break down larger fiber agglomerates into
smaller ones, or even into individual fibers, and wherein the
crystallizer is utilized at the same time as reactor for the
chemical precipitation reaction.
[0007] What is needed in the art is to further simplify a method
for loading of a fibrous stock suspension with calcium
carbonate.
SUMMARY OF THE INVENTION
[0008] The present invention provides a method including the
following process steps: adding of calcium hydroxide in liquid or
dry form, or of calcium oxide into the fibrous stock suspension;
adding of carbon dioxide into the fibrous stock suspension; and
precipitation of calcium carbonate from the calcium hydroxide
through the carbon dioxide in a pressurized pressure vessel.
[0009] The current invention describes a method for the production
of fiber loaded precipitated calcium carbonate (FLPCC), wherein the
fiber raw material that is to be loaded may include recycling
paper, DIP (deinked paper), secondary fibers, bleached or
unbleached pulp, mechanical pulp, bleached or unbleached sulfate
pulp, broke, linen, cotton, and/or hemp fibers (predominantly
cigarette paper) and/or any paper raw material which can be
utilized on a paper machine.
[0010] With the method according to the current invention the
currently used filler material is replaced, supplemented or
activated by the filler material which is produced by the fiber
loading process technology. Activation means that the already
existing filler particles are superimposed by the fiber loading
process or serve as a crystallization nucleus, thereby providing
improved optical characteristics.
[0011] The method is also especially suitable if paper which is
printed with flexo-ink (water based printing ink)--especially news
print--is used for the production of the fiber raw material. The
print particles including flexo-ink cannot be removed through a
floatation process, or can be removed only with great difficulty.
With the current invention it is now possible to integrate fillers
and foreign substances such as printing ink, contaminants,
stickies, etc., which are inherently present in DIP papers into the
fiber loading-crystallization process wherein the already present
filler particles are being superimposed by the fiber loading
process, or serve as crystallization nucleus.
[0012] The method is independent of whether or not the fiber raw
material contains a filler that was produced by a precipitation
process in a batch reactor or by a refining process, or whether
talcum, titanium dioxide (TiO.sub.2), silicon, etc., are used. The
refining process is also referred to as GCC-process (GCC=ground
calcium carbonate).
[0013] When a fibrous stock suspension is processed with the fiber
loading technology, a completely new product for application in
paper production will result, with new and improved characteristics
compared to a product according to the current state of the art.
The fiber loading technology permits precipitation of a
filler--especially calcium carbonate--that is uniformly distributed
and adhered to, in and between the fibers directly in the stock
preparation of a paper mill.
[0014] The range of application of the filler produced with the
fiber loading combination process technology extends to
applications within the paper production of all paper grades,
including cigarette papers, filter papers, kraft sack paper grades
and cardboard and packaging papers including those with which
recycling paper types and DIP papers are used. Packaging papers of
this type can have a filler content of between 1 and 60% and/or can
possess a white liner having a filler content of between 1 and 60%.
The loaded and manufactured paper grades can be produced on a paper
machine from a recycling paper, deinked paper (DIP), secondary
fibers, bleached or unbleached pulp, mechanical pulp, bleached or
unbleached sulfate pulp, broke, linen, cotton, hemp fibers
(predominantly for cigarette paper), and/or any paper raw material,
irrespective of whether or not the end product contains a
filler.
[0015] Fibrous stock produced according to the fiber loading
combination process technology generally possesses a superior
dewatering characteristic compared to a fibrous stock produced
according to another method; the dewatering capacity is between 5
to 100 ml CSF or 0.2 to 15.degree. SR, depending upon the required
freeness. The stock or pulp produced according to the fiber loading
process further possesses a lower water retention value of 2 to 25%
depending upon the raw material used in the production process.
This permits a more effective production of various paper grades,
for example FL (FL=fiber loaded) copy and printing paper of all
types, FL coating paper of all types, FL news print of all types
and FL cigarette paper of all types, FL B&P paper of all types,
FL kraft sack paper of all types and FL filter paper, since the
water in the stock suspension can be removed faster. The stock
therefore dries accordingly faster.
[0016] When a fibrous stock suspension is processed with the fiber
loading technology, a completely new product results which
possesses new and improved characteristics compared to the papers
available on the market. The fiber loading process which is
described below permits precipitation of a filler--especially
calcium carbonate--which is uniformly distributed and adhered to,
in and between the fibers directly in the stock preparation of a
paper mill.
[0017] By way of a combination or by way of an individual
application of the measures in accordance with the current
invention described below, only precipitated calcium carbonate for
the fiber loading process is produced and already present filler
material is activated.
[0018] By utilizing the fiber loading technology in the pulper or
in the batch-container, the optical characteristics of the paper
suspension and the raw material can be improved by 0.5 to 30
lightness points, preferably by 1 to 25 lightness
points--predominantly through masking of the contaminants such as
ink particles and dirt. In addition, a conversion of non-activated
fiber stock components, for example non-converted calcium
hydroxide, PCC (precipitated calcium carbonate), GCC (ground
calcium carbonate), lime components, etc. which are embedded in the
recycled paper raw material or in the DIP-pulp occurs.
[0019] In accordance with one design form aqueous fiber raw
material, especially aqueous paper raw material, having a
consistency of between 1 and 20% of fibrous stock content is fed
into the pressure vessel, wherein LC-fiber stock material (low
consistency) is used at a content of between 1 and 6%, MC-fiber
stock material (medium consistency) is used at a content of between
6 and 10%, and HC-fiber stock material (high consistency) is used
at a content of between 10 and 20%.
[0020] It is advantageous if the aqueous fiber raw material is
diluted to a fibrous stock suspension having a consistency of
between 0.1 and 20%, especially diluted to a consistency of between
2 and 18%.
[0021] In a suitable embodiment of the method the pressure vessel
is closed by a sluice after supplying the aqueous fiber stock
material and/or the dilution water.
[0022] It is advantageous if the calcium hydroxide or the calcium
oxide is mixed into the aqueous fiber stock in a range of between
0.1 and 60% of the existing solids content of the volume of the dry
fiber stock.
[0023] The pH value is preferably between 6 and 11, especially
between 6.5 and 10.5.
[0024] The reaction time is between 0.0005 and 30 minutes,
especially in a range of between 0.05 and 10 minutes.
[0025] The calcium carbonate can be precipitated advantageously
through adding the carbon dioxide in a pressure range of between 0
and 15 bar, especially between 0 and 6 bar.
[0026] One design form of the method provides that the fibrous
stock suspension and/or the carbon dioxide is heated by way of
process water or dilution water or steam during its dissolution in
the fibrous stock suspension, or by way of the fiber loading
process or through introducing heat energy from the outside,
especially by way of steam energy or electrical energy.
[0027] The carbon dioxide can be added prior to, during or after
the addition of the carbon dioxide or the calcium hydroxide or the
calcium oxide.
[0028] In this connection it is advantageous if the pressure vessel
is opened by a valve or a sluice before the fiber loading reaction,
or after the reaction.
[0029] The energy expenditure for the precipitation of the loaded
fibers is between 0.3 and 8 kWh/t, especially between 0.5 and 4
kWh/t, if no refiner for the fiber stock is used. A refiner may
also be installed before the vessel if the fiber pulp is already
sufficiently dissolved. In an alternative embodiment of the current
invention the refiner may also be installed downstream from the
pressure vessel.
[0030] The process temperature is preferably between -15.degree.
and 120.degree., especially between 20 and 90.degree. C.
[0031] Due to the fiber loading process rhombohedral, scalenohedron
and spherical crystals are formed.
[0032] Due to this process crystals having dimensions preferably of
between 0.05 and 5 .mu.m, especially between 0.3 and 2.5 .mu.m can
be produced.
[0033] Static and/or moving, especially rotating, mixing elements
can be utilized for the purpose of mixing the fibrous stock
suspension.
[0034] The process is preferably conducted in a pressure range of
between 0 and 15 bar, especially between 0 and 6 bar.
[0035] In an embodiment according to the present invention, it is
also possible to conduct a refining process in the pressure vessel,
at the same time as the precipitation process.
[0036] The present invention also relates to a device for the
implementation of the method.
[0037] In accordance with the present invention, the device is
characterized in that it includes an infeed device for the supply
of the fiber raw material, as well as a pressure vessel.
[0038] An advantageous embodiment of the device provides that the
pressure vessel includes a sluice or a valve through which the
fiber raw material is fed for the production of the fibrous stock
suspension with loaded fibers. The pressure vessel can be equipped
with inlets for dilution or press water, for calcium oxide or
calcium hydroxide and for carbon dioxide.
[0039] In addition the pressure vessel includes a rotor for mixing
the fibrous stock suspension.
BRIEF DESCRIPTION OF THE DRAWINGS
[0040] The above-mentioned and other features and advantages of
this invention, and the manner of attaining them, will become more
apparent and the invention will be better understood by reference
to the following description of embodiments of the invention taken
in conjunction with the accompanying drawing, wherein:
[0041] FIG. 1 illustrates a device for loading a fibrous stock
suspension including cellulose fibers with calcium carbonate
according to the present invention.
[0042] Corresponding reference characters indicate corresponding
parts throughout the several views. The exemplification set out
herein illustrates one embodiment of the invention, and such
exemplification is not to be construed as limiting the scope of the
invention in any manner.
DETAILED DESCRIPTION OF THE INVENTION
[0043] Referring now to the drawing, there is shown a fiber raw
material which is supplied to a pressure vessel 2 through a supply
pipe 1. In order to be able to establish and limit the supply
volume a sluice 3 which is opened and closed via a motor driven
closing mechanism is located between the supply pipe 1 and the
pressure vessel 2.
[0044] Dilution water, calcium hydroxide in liquid or solid form or
calcium oxide or chemicals are added through additional supply line
connections 4, 5, 6 so that, if the raw fiber stock was initially
supplied to a fill level 7, a filling of the pressure container 2
above this fill level 7 is formed, including the calcium hydroxide
which serves the fiber loading process, together with the water
and/or the dilution water in which it is dissolved.
[0045] In order to mix the fiber raw stock with the calcium
hydroxide so that this penetrates into the fibers, a rotor 8 is
supplied which includes a propeller wheel or similar device at the
bottom and/or at a higher level of the pressure container 2. The
rotor 8 is driven via a motor 9.
[0046] At least one inlet 10 can be provided in the lower area of
the pressure container 2 for carbon dioxide through which the
calcium hydroxide reacts to calcium carbonate. After the fiber raw
material has been dissolved and loaded with calcium carbonate it is
routed to a machine for the production of a fibrous web, through a
discharge pipe 12 which is equipped with a valve 11.
[0047] In addition a measuring location 13 can be provided on
pressure container 2 in order to measure the chemical composition
of the content in said pressure container 2, especially to measure
the pH value.
[0048] While this invention has been described with respect to at
least one embodiment, the present invention can be further modified
within the spirit and scope of this disclosure. This application is
therefore intended to cover any variations, uses, or adaptations of
the invention using its general principles. Further, this
application is intended to cover such departures from the present
disclosure as come within known or customary practice in the art to
which this invention pertains and which fall within the limits of
the appended claims.
Component Identification
[0049] 1 Supply pipe [0050] 2 Pressure container [0051] 3 Sluice
[0052] 4 Supply line connection [0053] 5 Supply line connection
[0054] 6 Supply line connection [0055] 7 Filling level [0056] 8
Rotor [0057] 9 Motor [0058] 10 Inlet for carbon dioxide [0059] 11
Valve [0060] 12 Discharge pipe [0061] 13 Measuring location
* * * * *