U.S. patent application number 10/575541 was filed with the patent office on 2007-03-08 for method and apparatus for loading a fibrous stock suspension.
Invention is credited to Klaus Doelle.
Application Number | 20070051480 10/575541 |
Document ID | / |
Family ID | 34441956 |
Filed Date | 2007-03-08 |
United States Patent
Application |
20070051480 |
Kind Code |
A1 |
Doelle; Klaus |
March 8, 2007 |
Method and apparatus for loading a fibrous stock suspension
Abstract
An apparatus for loading a cellulose fiber containing fibrous
stock suspension with calcium carbonate which includes an
arrangement of machines for loading the fibrous stock suspension
with calcium carbonate, whereby the machines are supplied with flue
gas which contains carbon dioxide. The machines are followed by a
deaeration unit for the removal of superfluous gas.
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: |
34441956 |
Appl. No.: |
10/575541 |
Filed: |
October 11, 2004 |
PCT Filed: |
October 11, 2004 |
PCT NO: |
PCT/EP04/52490 |
371 Date: |
June 13, 2006 |
Current U.S.
Class: |
162/9 ; 162/10;
162/17; 162/181.2; 162/183; 162/24; 162/241; 162/242; 162/243;
162/57; 422/600 |
Current CPC
Class: |
D21C 9/004 20130101;
D21C 11/06 20130101 |
Class at
Publication: |
162/009 ;
162/181.2; 162/183; 162/024; 162/057; 162/010; 162/017; 162/241;
162/242; 162/243; 422/188; 422/194 |
International
Class: |
D21C 9/00 20060101
D21C009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 15, 2003 |
DE |
10347920.1 |
Claims
1-19. (canceled)
20. A method for loading a fibrous stock suspension including
chemical pulp fibers with calcium carbonate, comprising the steps
of: adding one of calcium hydroxide, and calcium oxide into the
fibrous stock suspension, said calcium hydroxide being in one of a
liquid and dry form; feeding a flue gas containing carbon dioxide
into the fibrous stock suspension; precipitating of the calcium
carbonate through said carbon dioxide contained in said flue gas;
and removing superfluous said flue gas after said precipitating
step.
21. The method of claim 20, wherein said flue gas has a carbon
dioxide content of approximately between 2% and 30% when added into
the fibrous stock suspension.
22. The method of claim 20, further including the step of applying
a refining force in a refining step, said refining force in a range
of approximately between 0.1 kWh per ton of dry fiber stock and 300
kWh per ton of dry fiber stock, whereby the loading method and said
refining step are accomplished in an apparatus.
23. The method of claim 20, further including the step of using an
aqueous fibrous stock material as a primary raw material.
24. The method of claim 23, wherein said aqueous fibrous has a
consistency of approximately between 0.1% to 20%.
25. The method of claim 24, wherein said aqueous fibrous has a
consistency of approximately between preferably between 2% and
6%.
26. The method of claim 23, wherein said calcium hydroxide is added
through one of a static mixer and an intermediate tank.
27. The method of claim 20, further including the step of utilizing
at least one of a static mixer, a refiner, a disperger, and a
fluffer FLPCC reactor as a reactor.
28. The method of claim 27, wherein a fibrous stock content is one
of approximately between 0.01% and 15% in the instance of said
static mixer; is approximately between 2% and 40% in the instance
of said refiner, is approximately between 2% and 40% in the
instance of said disperger, and is approximately between 15% and
60% in the instance of 5 said fluffer FLPCC reactor.
29. The method of claim 20, further including the step of adding a
dilution water one of prior to, during and after the addition of at
least one of said carbon dioxide, said calcium hydroxide and said
calcium oxide.
30. The method of claim 20, wherein an expenditure of energy of
approximately between 0.3 kWh/t and 8 kWh/t is used for said
precipitating step.
31. The method of claim 30, wherein said expenditure of energy is
approximately between 0.5 kWh/t and 4 kWh/t.
32. The method of claim 20, further including the step of
maintaining a process temperature approximately between -15.degree.
C. and 120.degree. C.
33. The method of claim 32, wherein said process temperature is
maintained approximately between 20.degree. C. and 90.degree.
C.
34. The method of claim 20, further including the step of producing
at least one of rhombohedral crystals of calcium carbonate,
scalenohedron crystals of calcium carbonate and spherical crystals
of calcium carbonate.
35. The method of claim 34, wherein said crystals measure
approximately between 0.05 .mu.m and 5 .mu.m.
36. The method of claim 35, wherein said crystals measure
approximately between 0.3 .mu.m and 2.5 .mu.m.
37. The method of claim 20, further including the step of utilizing
at least one of static mixing elements, moving mixing elements and
rotating mixing elements.
38. The method of claim 20, further including the step of carrying
out said method in a pressure range of approximately between 0 bar
and 15 bar.
39. The method of claim 38, wherein said pressure range is
approximately between 0 bar and 6 bar.
40. The method of claim 20, further including the step of carrying
out said method at a ph value of approximately between 6 and
10.
41. The method of claim 40, wherein said ph value is approximately
between 6.5 and 8.5.
42. The method of claim 20, wherein said precipitating step
includes a reaction time approximately between 0.05 seconds and 1
minute.
43. The method of claim 42, wherein said reaction time is
approximately between 0.05 seconds and 10 seconds.
44. An apparatus for loading a fibrous stock suspension including
chemical pulp fibers with calcium carbonate, said apparatus
comprising: an arrangement of machines for loading the fibrous
stock suspension with calcium carbonate being supplied with a flue
gas containing carbon dioxide; and a deaeration unit following said
machine, said deaeration unit for the removal of superfluous said
flue gas.
45. The apparatus of claim 44, wherein said flue gas from an
incineration plant is supplied to one of a gas motor and a gas
turbine.
46. The apparatus of claim 44, wherein said deaeration unit
comprises at least one of a chest with an agitator, a pressure
screen, a deaeration pump, a cyclone, a cleaner and a
deculator.
47. The apparatus of claim 44, further including an intermediate
tank installed after said deaeration unit as viewed in a fiber
stock flow direction.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a method for loading of a
fibrous stock suspension with calcium carbonate.
[0003] 2. Description of the Related Art
[0004] Several methods for loading chemical pulp fibers with
calcium carbonate are known. A method is described in U.S. Pat. No.
6,413,365 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.
[0005] A method for loading a fibrous stock suspension is described
in German Patent No. DE 100 33 978 A1 whereby a medium which
contains calcium oxide and/or calcium hydroxide, and pure carbon
dioxide or a carbon dioxide containing medium are added to the
fibrous stock suspension. According to U.S. Patent Application
Publication 2002/0088566 A1 a combustion process is utilized in
order to produce carbon dioxide, whereby said combustion process is
process linked with the device for the production of the fibrous
stock suspension. A method for loading a fibrous stock suspension
is known from German Patent No. DE 101 20 637 A1 whereby the carbon
dioxide is produced from the waste-gas of a fuel or by lime
burning. The carbon dioxide has a percentage purity of between 65
and 99% and is contained, for example in the waste gas of a power
station, a combustion motor, a boiler or a device for direct
burning of fossil fuel.
[0006] What is needed in the art is to further improve a method and
apparatus for loading a fibrous stock suspension with calcium
carbonate.
SUMMARY OF THE INVENTION
[0007] The present invention further improves a method and
apparatus for loading a fibrous stock suspension with calcium
carbonate.
[0008] In accordance with the present invention a method is
disclosed including the following process steps: [0009] feeding of
calcium hydroxide in liquid or dry form, or of calcium oxide into
the fibrous stock suspension; [0010] feeding of a flue gas which
contains carbon dioxide into the fibrous stock suspension; [0011]
precipitation of calcium carbonate through the carbon dioxide which
is contained in the flue gas; and [0012] removal of the superfluous
flue gas.
[0013] The present invention describes a method for the production
of fiber loaded precipitated calcium carbonate (FLPCC) and to
simultaneously undergo a refining process, whereby 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 fibrous raw material that can be utilized on a paper machine,
irrespective of whether or not the end product contains a filler
that was produced by a precipitation process in batch reactors 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).
[0014] When a fibrous stock suspension is processed with the fiber
loading technology of the present invention a completely new
product for application in paper production results, 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. It also allows
the treated fibrous stock to undergo a refining treatment in a
refiner simultaneously with the precipitation process.
[0015] The process for the production of precipitated calcium
carbonate with simultaneous refining with the assistance of the
fiber loading combination process occurs according to a process
known in the art, whereby reference is made also to German Patent
Nos. DE 101 07 448 A1, DE 101 13 998 A1 and U.S. Pat. No. 6,413,365
B1, these patents incorporated here by reference in addition to the
publications referred to at the beginning.
[0016] In accordance with the FLPCC combination process described
under the present invention the filler material utilized according
to the current state of the art is replaced with the filler
material produced according to the fiber loading combination
process technology. 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 that have a filler content of
between 1 and 60% and/or a white liner having a filler content of
between 1 and 60%. The loaded and produced 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,
and/or hemp fibers (predominantly for cigarette paper) and/or any
paper raw material, irrespective of whether or not the end product
contains a filler.
[0017] 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 improvement in 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
that is used in production. 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.
[0018] In the instance of FL cigarette paper, FL B&P paper, FL
kraft sack paper and FL filter paper which do not require fillers,
the loose filler can be removed by way of an additionally provided
washing process prior to the refining process, following the
refining process or after running through the headbox chest or
prior to feeding into the paper machine. This applies to the filler
that is not deposited in or on the fibers and can be washed out
accordingly. The fibers themselves still contain filler, inside and
out so that the positive effects of the fiber loading technology
can be taken advantage of.
[0019] The fiber loading technology may be utilized prior to or
after the refining process, depending on what requirements are put
upon the end product.
[0020] Compared to the current state of the art, a higher freeness
value can be achieved with the fiber loading combination technology
of the present invention, since up to 50% of refining energy can be
saved; this has an especially positive influence with all the paper
grades which pass through a refining process during their
production, or which possess a very high freeness value, for
example FL-cigarette papers, FL B&P papers, FL kraft sack
papers and FL filter papers. In particular, these are FL cigarette
papers having 100 to 25 CSF or 68 to 90.degree. SR, FL B&P
papers having 600 to 50 CSF or 20 to 80.degree. SR, FL sack papers
having 600 to 425 CSF or 20 to 30.degree. SR and FL filter papers
having 600 to 350 CSF or 20 to 35.degree. SR.
[0021] The high mechanical strengths in the end product which are
achieved through the high freeness value positively affect the
production of FL cigarette papers, FL B&P papers, FL sack
papers and FL filter papers since, due to process based mechanical
loads in the various section of the paper machine, such as the
press section, the dryer section and in the area where the web is
wound, the produced intermediate product and the end product which
is to be produced bears a high mechanical load due to utilization
of winders, rewinders and converting machinery. Great mechanical
stresses occur on the paper, especially in the production of
cigarette paper, which are also partially caused by the low basis
weight and the utilization of winders.
[0022] More effective drying to a residual moisture content of 1 to
20% permits an increase in efficiency for all paper grades. A
higher water retention capacity, i.e. 1 to 25% results in a
positive influence upon remoistening which is lower in the
manufacturing process, as well as upon the printability of the
produced web. An additional advantage for all paper grades is the
greater brightness or the higher optical values with around 15 or
more lightness points, which is to be emphasized in the production
of all grades of paper and cardboard, with or without white liner.
By using the fiber loading technology of the present invention the
optical values, for example in cigarette papers, are also improved
by up to 15 lightness points when using for example deinking
water.
[0023] An additional advantage of fiber loading with the above
referenced paper grades is found in that for special applications
calendering is provided and in doing so the so-called blackening
due to deposits of FL particles in, around and on the fibers is
suppressed or eliminated through utilization of the fiber loading
process.
[0024] By utilizing flue gas the carbon dioxide emissions produced
by a paper factory can be reduced by utilizing the carbon dioxide
that is contained in the flue gas for the fiber loading process. An
additional advantage is that by utilizing the carbon dioxide that
is contained in the flue gas transportation and storage of liquid
carbon dioxide can be saved.
[0025] Advantageous design forms of the present invention can be
seen in the dependent claims, the description and the drawing.
[0026] The flue gas which is being used in accordance with an
inventive method has, for example, a carbon dioxide content of
between 2 and 30%. The flue gas can be cleaned for example in a
scrubber prior to introducing it into the fiber loading process, as
described in German Patent No. DE 101 20 637 A1, incorporated
herein by reference [sections 0010-0011], wash tower 14 in the only
drawing and associated description].
[0027] It is advantageous if a refining energy in the range of
between 0.1 and 300 kWh per ton of dry fiber stock is applied
during loading of the fibrous stock suspension with calcium
carbonate. Loading and refining would preferably be conducted in
separate and independent process steps in one device.
[0028] In accordance with one design form of the present invention
aqueous fibrous stock material, especially aqueous fiber stock
having a consistency of 0.1 to 20%, preferably between 2 and 8%, is
used as primary raw material.
[0029] In accordance with the present invention calcium hydroxide
is mixed as the preferred filler into the aqueous fiber stock
material, especially into the fiber stock, whereby this has a
solids content of between 0.01 and 60%. In accordance with the
present invention utilization of a source material other than
calcium hydroxide or calcium oxide for formation of the filler is
also feasible.
[0030] The calcium hydroxide is added through a static mixer or an
intermediate tank. The carbon dioxide is preferably added into a
moist fibrous stock suspension having a preferred consistency of
0.1 to 60%, according to the reaction parameters. Calcium carbonate
is precipitated in a carbon dioxide gaseous atmosphere.
[0031] In accordance with the present invention the refining
process is carried out simultaneously with the fiber loading
process in an apparatus, the crystallizer; a refining energy in the
range between 0.1 and 300 kWh/ton dry fiber stock is applied; a
short reaction time of the calcium hydroxide with the carbon
dioxide is important in this context. The energy supply or heat
volume, or heating of the fibrous suspension for the production of
crystals in various forms is important for the present
invention.
[0032] Depending upon application of the respective reaction
machine, aqueous fibrous stock with a fiber content of between 0.01
and 60% is used as primary raw material.
[0033] An advantageous embodiment of the method according to the
present invention provides that a static mixer, a refiner, a
disperger and/or a fluffer FLPCC reactor are utilized as a reactor,
whereby the fibrous stock content, especially the fiber content is
between 0.01 and 15% in the instance of a static mixer; at between
2 and 8% in the instance of a refiner (low consistency refining)
and between 20 and 35% (high consistency refining), and in the
instance of a disperger between 2 and 40%, and 15 and 60% in the
instance of a fluffer-FLPCC-reactor.
[0034] The present invention provides that the dilution water is
supplied prior to, during or after the addition of carbon dioxide
or calcium hydroxide or calcium oxide. Calcium carbonate
precipitates when adding carbon dioxide into a calcium hydroxide
solution or suspension. Conversely, the precipitative reaction also
occurs, when calcium hydroxide is added to water under a carbon
dioxide atmosphere. Dilution water may be added prior to, during or
after the addition of carbon dioxide or calcium hydroxide.
[0035] An expenditure of energy of between 0.3 and 8 kWh/t,
especially between 0.5 and 4 kWh/t is preferably used for the
precipitation reaction when no refiner is used. Likewise it can be
provided that the process temperature is between -15.degree. C. and
120.degree. C., especially between 20 and 90.degree. C. According
to the present invention rhombohedral, scalenohedron and spherical
crystals can be formed.
[0036] Advantageously, the crystals measure between 0.05 and 5
.mu.m, especially between 0.3 and 2.5 .mu.m. Static and/or moving,
especially rotating mixing elements may be utilized. The process is
preferably carried out in a pressure range of between 0 and 15 bar,
especially between 0 and 6 bar. The pH value is preferably between
6 and 10, especially between 6.5 and 8.5. The reaction time is
advantageously between 0.05 seconds and 1 minute, especially
between 0.05 seconds and 10 seconds.
[0037] The present invention relates to a device which includes
machines for loading the fibrous stock suspension with calcium
carbonate. These are supplied with flue gas containing carbon
dioxide. The machines are followed by a deaeration unit for the
removal of superfluous gas. The configuration of the machinery is
basically known from the documentation cited above. A further
advancement of the device provides that the flue gas from an
incineration plant can be supplied especially to a gas motor or gas
turbine. The deaeration unit preferably includes a chest with an
agitator, a pressure screen, a deaeration pump, a cyclone, a
cleaner and/or a deculator.
[0038] A further development of the present invention is
advantageous whereby an intermediate tank is installed after the
deaeration unit, viewed in fiber stock flow direction.
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] 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 an embodiment of the invention
taken in conjunction with the sole drawing which is a schematic
view of an embodiment of an apparatus for loading of a fibrous
stock suspension according to the present invention. The
exemplification set out herein illustrates one preferred embodiment
of the invention, in one form, and such exemplification is not to
be construed as limiting the scope of the invention in any
manner.
DETAILED DESCRIPTION OF THE INVENTION
[0040] Referring now to the sole FIGURE, there is shown a fibrous
stock suspension 1 which is supplied to an arrangement 2 of
machinery for the fiber loading process. In addition, flue gas 3 is
also supplied to arrangement 2 from a storage container 4 via a gas
pump 5. The flue gas may, for example originate from a power
station, an incineration device, a combustion motor, a boiler, or
similar device.
[0041] Fibrous stock suspension 1 which has absorbed carbon dioxide
from flue gas 3 is now transported from arrangement 2 to a
deaeration device 6 where the carbon dioxide which was not absorbed
by said fibrous stock suspension and the non-usable residual gas
are again removed. The fibrous stock suspension is subsequently
transported to an intermediate tank 7. The purpose of intermediate
tank 7 is for example to store fibrous stock suspension 1 before it
is transported on to a head box in a paper machine, or to another
machine for the production of a fiber web.
[0042] While this invention has been described as having a
preferred design, 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.
* * * * *