U.S. patent application number 17/349071 was filed with the patent office on 2021-10-07 for method and apparatus for separating lignocellulose particle fraction and lignin particle fraction, lignin particle composition, lignocellulose particle composition and their use.
The applicant listed for this patent is UPM-KYMMENE CORPORATION. Invention is credited to Mauno MIETTINEN.
Application Number | 20210309809 17/349071 |
Document ID | / |
Family ID | 1000005655043 |
Filed Date | 2021-10-07 |
United States Patent
Application |
20210309809 |
Kind Code |
A1 |
MIETTINEN; Mauno |
October 7, 2021 |
METHOD AND APPARATUS FOR SEPARATING LIGNOCELLULOSE PARTICLE
FRACTION AND LIGNIN PARTICLE FRACTION, LIGNIN PARTICLE COMPOSITION,
LIGNOCELLULOSE PARTICLE COMPOSITION AND THEIR USE
Abstract
The invention relates to a method and an apparatus for
separating lignocellulose particle fraction (3) and lignin particle
fraction (4), in which crude lignin (1) formed from starting
material (6) comprises lignocellulose particles and lignin
particles. According to the invention, the method comprises adding
stabilizing chemical (11) and/or hydrophobic chemical (12) into the
crude lignin (1) in at least one step, and treating the crude
lignin by separating the lignin particle fraction (4) and
lignocellulose particle fraction (3) from each other in at least
one separation step (2,8,9,10). Further, the invention relates to a
lignocellulose particle fraction and a lignin particle fraction and
their uses.
Inventors: |
MIETTINEN; Mauno;
(Lappeenranta, FI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
UPM-KYMMENE CORPORATION |
Helsinki |
|
FI |
|
|
Family ID: |
1000005655043 |
Appl. No.: |
17/349071 |
Filed: |
June 16, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15110784 |
Jul 11, 2016 |
11066525 |
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PCT/FI2015/050010 |
Jan 9, 2015 |
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17349071 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B01J 20/3085 20130101;
B03D 3/06 20130101; C08H 8/00 20130101; C08L 2205/02 20130101; C08H
6/00 20130101; B01J 20/24 20130101; D21H 17/23 20130101; B01J
20/28016 20130101; B01D 21/00 20130101; B03D 1/02 20130101; C08L
97/02 20130101; C08L 97/005 20130101; B03D 2203/001 20130101 |
International
Class: |
C08H 8/00 20060101
C08H008/00; C08H 7/00 20060101 C08H007/00; C08L 97/00 20060101
C08L097/00; C08L 97/02 20060101 C08L097/02; B03D 1/02 20060101
B03D001/02; B01J 20/24 20060101 B01J020/24; B01J 20/28 20060101
B01J020/28; B01J 20/30 20060101 B01J020/30; B03D 3/06 20060101
B03D003/06 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 13, 2014 |
FI |
20145020 |
Claims
1. A method for separating a lignocellulose particle fraction and a
lignin particle fraction from crude lignin, the method comprising:
adding a stabilizing chemical and, optionally, a hydrophobic
chemical into the crude lignin in at least one step, wherein the
crude lignin is formed from a wood or plant-based raw material, and
separating the lignin particle fraction and the lignocellulose
particle fraction from the crude lignin in more than one
solid-solid separation step.
2. (canceled)
3. The method according to claim 1 wherein the at least one
solid-solid separation step includes application of centrifugal
forces, sedimentation, elutriation, aggregation, flotation,
flocculation, screening, or any combination thereof.
4. The method according to claim 1, wherein the crude lignin is
formed by hydrolysis.
5. The method according to claim 1, wherein the stabilizing
chemical is polysaccharide.
6. The method according to claim 1, wherein the hydrophobic
chemical includes diesel oil, biodiesel oil, fuel oil, bio fuel
oil, kerosene, biokerosene, other middle distillate fraction, or
any combination thereof.
7. The method according to claim 2, wherein the lignin particle
fraction and lignocellulose particle fraction are separated from
each other in the first separation step.
8. The method according to claim 1, further comprising purifying
the lignocellulose particle fraction in at least one purification
step.
9. The method according to claim 1, further comprising purifying
the lignin particle fraction in at least one purification step.
10. The method according to claim 1 further comprising: forming the
crude lignin from a starting material; and circulating the
lignocellulose particle fraction such that the lignocellulose
particle fraction is combined with the starting material to form
additional crude lignin.
11. An apparatus for separating a lignocellulose particle fraction
and a lignin particle fraction from crude lignin, the apparatus
comprising: at least two solid-solid separating devices for
separating the lignin particle fraction and the lignocellulose
particle fraction from the crude lignin in more than one
solid-solid separation step, wherein the crude lignin is formed
from a wood or plant-based raw material; at least one first feeding
device for feeding the crude lignin into the at least one
solid-solid separating device; and at least one second feeding
device for adding a stabilizing chemical and, optionally, a
hydro-phobic chemical into the crude lignin in at least one
step.
12. (canceled)
13. The apparatus according to claim 11, wherein the at least one
solid-solid separating device is configured to apply centrifugal
forces, sedimentation, elutriation, aggregation, flotation,
flocculation, screening, or any combination thereof.
14. The apparatus according to claim 11, further comprising: a
circulations means for circulating the lignocellulose particle
fraction to combine it with starting material used to form the
crude lignin.
15. The apparatus according to claim 11, wherein the apparatus
comprises at least one dewatering device for dewatering the lignin
particle fraction or the lignocellulose particle fraction.
16. A lignin particle composition, comprising: a lignin particle
fraction of crude lignin and the crude lignin comprising
lignocellulose particles and lignin particles, wherein the lignin
particle fraction has been formed from the crude lignin by adding
stabilizing chemical and, optionally, hydrophobic chemical into the
crude lignin in at least one step, wherein the crude lignin is
formed from a wood or plant-based raw material, and by separating
the lignocellulose particle fraction from the lignin particle
fraction in more than one solid-solid separation step.
17. A lignocellulose particle composition comprising: a
lignocellulose particle fraction of crude lignin, the crude lignin
comprising lignocellulose particles and lignin particles, wherein
the lignocellulose particle fraction has been formed from the crude
lignin by adding stabilizing chemical and, optionally, hydrophobic
chemical into the crude lignin in at least one step, wherein the
crude lignin is formed from a wood or plant-based raw material, and
by separating the lignin particle fraction from the lignocellulose
particle fraction in more than one solid-solid separation step.
18-20. (canceled)
Description
FIELD OF THE INVENTION
[0001] The invention relates to a method and an apparatus for
separating lignocellulose particle fraction and lignin particle
fraction. Further, the invention relates to a lignin particle
composition and a lignocellulose particle composition and their
uses.
BACKGROUND OF THE INVENTION
[0002] Known from prior art is different methods for forming lignin
from different raw materials, such as biomass. Many bio-refinery
processes, e.g. hydrolysis, generate crude lignin, such as lignin
residue, after hydrolysis of biomass. This water-insoluble lignin
residue usually contains significant percentage of non-hydrolyzed
lignocellulose particles together with free lignin particles.
[0003] Further, known from prior art is to treat lignin chemically
by dissolving lignin in dissolvent, such as in NaOH, alcohol-water
mixture or organic acid, and to precipitate lignin, e.g. by
sulphuric acid or water. Then pure lignin can be provided, but
known processes suffer from high operating and capital costs.
Removing and/or recovering of dissolvent or formed salt lead to
additional costs. Final dewatering of lignin is usually carried out
by filtration. Size of precipitated lignin particle is generally
rather small, which has negative effect on filtration rate and dry
solids content of filter cake.
Objective of the Invention
[0004] The objective of the invention is to disclose a new method
for separating lignocellulose particle fraction and lignin particle
fraction. Another objective of the invention is to disclose a new
method for purifying lignin. Another objective of the invention is
to produce a purified lignin particle composition and
lignocellulose particle composition with improved properties.
SUMMARY OF THE INVENTION
[0005] The method for separating lignocellulose particle fraction
and lignin particle fraction according to the present invention is
characterized by what is presented in claim 1.
[0006] The apparatus for separating lignocellulose particle
fraction and lignin particle fraction according to the present
invention is characterized by what is presented in claim 11.
[0007] The lignin particle composition according to the present
invention is characterized by what is presented in claim 16.
[0008] The lignocellulose particle composition according to the
present invention is characterized by what is presented in claim
17.
[0009] The use of the lignin particle composition according to the
present invention is characterized by what is presented in claims
18 and 19.
[0010] The use of the lignocellulose particle composition according
to the present invention is characterized by what is presented in
claim 20.
BRIEF DESCRIPTION OF THE FIGURES
[0011] The accompanying drawings, which are included to provide a
further understanding of the invention and constitutes a part of
this specification, illus-trate some embodiments of the invention
and together with the description help to explain the principles of
the invention. In the drawings:
[0012] FIG. 1 is a flow chart illustration of a method according to
one embodiment of the present invention,
[0013] FIG. 2 is a flow chart illustration of a method according to
another embodiment of the present invention,
[0014] FIG. 3 is a flow chart illustration of a method according to
another embodiment of the present invention, and
[0015] FIG. 4 is a flow chart illustration of a method according to
another embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0016] The invention relates to a method for separating
lignocellulose particle fraction (3) and lignin particle fraction
(4). In the method of the present invention crude lignin (1) formed
from starting material (6) comprises lignocellulose particles and
lignin particles, wherein the method comprises: adding stabi-lining
chemical (11) and/or hydrophobic chemical (12) into the crude
lignin (1), such as into the crude lignin or fraction of the crude
lignin, in at least one step; and treating the crude lignin by
separating the lignin particle fraction (4) and lignocellulose
particle fraction (3) from each other in at least one separation
step (2,8,9,10). In a preferred embodiment, the lignin particle
fraction is a purified crude lignin.
[0017] One embodiment of the method of the present invention is
shown in FIG. 1. Another embodiment of the method of the present
invention is shown in FIG. 2. Another embodiment of the method of
the present invention is shown in FIG. 3. Another embodiment of the
method of the present invention is shown in FIG. 4.
[0018] The apparatus of the present invention comprises at least
one separating device for separating the lignin particle fraction
(4) and lignocellulose particle fraction (3) from each other in at
least one separation step (2,8,9,10), at least one first feeding
device for feeding the crude lignin (1) into the separating device,
and at least one second feeding device for adding stabilizing
chemical (11) and/or hydrophobic chemical (12) into the crude
lignin (1), such as into the crude lignin or fraction of the crude
lignin, in at least one step.
[0019] The invention is based on a solid-solid separation. Further,
the invention is based on a combination of chemical and mechanical
methods. According to the invention, separation of lignocellulose
particles from free lignin particles is important to increase value
of lignin composition in various applications. Simultaneously the
crude lignin, i.e. lignin composition, is purified. According to
the invention, lignocellulose composition can be produced. In the
present invention the lignocellulose particles may be circulated
back to hydrolysis process.
[0020] In this context, starting material (6) means any wood or
plant based raw material. The starting material includes lignin,
lignocellulose and hemicellulose. In one embodiment, the starting
material is selected from the group consisting of wood based raw
material, lignin containing biomass such as agricultural resi-dues,
bagasse and corn stover, woody perennials, vas-cular plants and
their combinations.
[0021] In this context, crude lignin (1) refers any material or
composition containing lignin particles, such as free lignin
particles. Further, the crude lignin contains also lignocellulose
particles. Mainly, the crude lignin comprises cellulose and lignin,
but may contain also hemicelluloses. The crude lignin may contain
one or more lignin material components. The crude lignin may
contain different amounts of lignin particles and lignocellulose
particles. Typically, the crude lignin is in the form of suspension
which contains water, acid, e.g. formic acid, acetic acid or
sulfuric acid, alcohol or other liquid, or in the form cake, lump
or the like. In one embodiment, the crude lignin has been diluted
with liquid, e.g. with water, and DS is between 1-20%, preferably
between 1-10%. Low consistency of suspension aids mechanical
separation of free lignin particles and lignocellulose particles.
In one embodiment, weight average particle size of the crude lignin
is below 1000 .mu.m, preferably below 500 .mu.m.
[0022] Preferably, the crude lignin (1) is formed by means of
hydrolysis (5). In one embodiment, the hydrolysis is selected from
the group consisting of acid hydrolysis, enzymatic hydrolysis,
supercritical hydrolysis, subcritical hydrolysis and their
combinations. The method of the invention can be used in connection
with any hydrolysis process. In one embodiment, the crude lignin is
a lignin residue from the hydrolysis or cellulignin.
[0023] In one embodiment, the cellulose content, i.e. glucan
content, of the crude lignin (1) is 3-70% by weight, preferably
5-60 by weight and more preferable 10-45% by weight, analyzed as
glucose.
[0024] In one embodiment, lignocellulose particles (3) are in the
form of fiber sticks in the crude lignin. In one embodiment, weight
average particle size of the lignocellulose particle is below 1 mm,
in one embodiment below 0.5 mm and in one embodiment below 300
.mu.m.
[0025] The stabilizing chemical (11) and/or hydro-phobic chemical
(12) are added into the crude lignin (1), such as into the crude
lignin or fraction of the crude lignin or purified crude lignin, in
at least one step. In one embodiment, the stabilizing chemical (11)
and/or hydrophobic chemical (12) are added into the crude lignin
(1) in one step. In one embodiment, the stabilizing chemical (11)
and/or hydrophobic chemical (12) are added into the crude lignin or
fraction of the crude lignin or purified crude lignin in more than
one step. In one embodiment, the stabilizing chemical (11) and/or
hydrophobic chemical (12) are added into the crude lignin or
fraction of the crude lignin or purified crude lignin in connection
with each separation step. In one embodiment, the stabilizing
chemical (11) and/or hydrophobic chemical (12) are added into the
crude lignin or fraction of the crude lignin or purified crude
lignin in the first separation step and/or in at least one later
separation step.
[0026] In one embodiment, stabilizing chemical (11) is added into
the crude lignin (1), such as into the crude lignin or fraction of
the crude lignin or purified crude lignin. In one embodiment,
hydrophobic chemical (12) is added into the crude lignin (1), such
as into the crude lignin or fraction of the crude lignin or
purified crude lignin. In one embodiment, stabilizing chemical (11)
and hydrophobic chemical (12) are added into the crude lignin (1),
such as into the crude lignin or fraction of the crude lignin or
purified crude lignin. In one embodiment, different combinations of
stabilizing chemical (11) and hydrophobic chemical (12) may be
added in different separation steps. In one embodiment, the
stabilizing and hydro-phobic chemicals are dosed simultaneously. In
one embodiment, the stabilizing and hydrophobic chemicals are dosed
sequentially. In one embodiment, the stabilizing and hydrophobic
chemicals are added into the crude lignin and the crude lignin is
mixed, preferably by high-shear mixing. The chemicals can be added
into slurry of low or high dry solids content. The high-shear
mixing is beneficial to facilitate adsorption of chemicals,
especially hydrophobic chemical, on surfaces. The stabilizing
chemical predominantly adsorbs on lignocellulose particles, while
the hydrophobic chemical predominantly adsorbs on free lignin
particles.
[0027] In one embodiment, the stabilizing chemical (11) is
polysaccharide as such or modified polysaccharide. In this context,
the stabilizing chemical is typically hydrophilic chemical. In one
embodiment, the stabilizing chemical is selected from the group
consisting of carboxymethyl cellulose (CMC), polyanionic cellulose
(PAC), other cellulose derivatives, e.g. ethylhydroxyethyl
cellulose and methyl cellulose, native guar gum, modified guar gum,
native starch, modified starch, pectin, glycogen, callose,
chrysolaminar in, native hemicellulose, modified hemicellulose,
xylan, mannan, galactomannan, galactoglucomannan (GGM),
arabinoxylan, glucuronoxylan and xyloglucan, fucoidan, dextran,
alginate, other polysaccharide and their combinations. Said
stabilizing chemical may be in native form or in modified form. In
one embodiment, the stabilizing chemical is carboxymethyl cellulose
(CMC). Preferably, function of the stabilizing chemical is to keep
suspended lignocellulose particles stable through chemical
interaction. Therefore, treated lignocellulose particles remain in
suspension while free lignin particles are separated from
suspension.
[0028] In one embodiment, the hydrophobic chemical (12) is selected
from the group consisting of fuel oil, bio fuel oil, diesel oil,
biodiesel oil, naphta, bionaphta, kerosene, biokerosene, other
middle distillate fraction, gasoline, biogasoline, naphthalene,
bionaphthalene, mineral spirit, other hydrocarbon solvent and their
combinations. In one embodiment, the hydrophobic chemical is oil
based chemical or bio-oil based chemical. In one embodiment, the
hydrophobic chemical is selected from the group consisting of
diesel oil, biodiesel oil, fuel oil, bio fuel oil, kerosene,
biokerosene, other middle distillate fraction, and their
combinations. Preferably, function of the hydrophobic chemical is
to cause aggregation of lignin particles together with stabilizing
chemical. Increase in particle size of the lignin will help
separation by mechanical means. It will also increase
hydrophobicity of the lignin particles thus facilitating
dewatering. Need for the hydrophobic chemical is determined by
surface properties of free lignin particles, which are largely
dependent on physico-chemical conditions in previous process
stages. The hydrophobic chemical has non-polar nature.
[0029] In one embodiment, pH is adjusted in the crude lignin before
the separating. In one embodiment, pH is adjusted to value between
5-7.
[0030] In one embodiment, the separation of the lignocellulose
particle fraction and lignin particle fraction is carried out in pH
range between 1-10, preferably between 5-9. Often near neutral pH,
such as pH between 5-9, stabilizes the lignocellulose particles
thus facilitating separation. On the other hand, acidic conditions
destabilize the lignin particles improving separation at low pH
values.
[0031] The separation can be carried out in wide temperature range,
e.g. temperatures between 0-100.degree. C. Higher temperature
usually aids the separation due to lower viscosity. Generally near
natural process temperature is utilized to avoid heating or
cooling. In one embodiment, the lignin particle fraction (4) and
lignocellulose particle fraction (3) are separated from each other
by means of a separation method selected from the group consisting
of centrifugal forces, sedimentation, elutriation, aggregation,
flotation, flocculation, screening and their combinations. In one
embodiment, the separating is made by means of centrifugal forces.
In one embodiment, the separating is made by means of
sedimentation. In one embodiment, the separating is made by means
of elutriation. In one embodiment, the separating is made by means
of agglomeration. In one embodiment, the separating is made by
means of flocculation. In one embodiment, the separating is made by
means of flotation. In one embodiment, the separating is made by
means of screening. In a preferred embodiment, the lignin particle
fraction (4) and lignocellulose particle fraction (3) are separated
from each other so that the lignocellulose particle fraction (3) is
separated from the crude lignin (1) and remaining crude lignin is
the lignin particle fraction (4), i.e. the purified crude
lignin.
[0032] In one embodiment, the apparatus comprises at least two
separating device for separating the lignin particle fraction (4)
and lignocellulose particle fraction (3) and/or purifying the
lignin particle fraction (4) and/or purifying lignocellulose
particle fraction (3). In one embodiment, the separating device is
based on centrifugal forces, sedimentation, elutriation,
aggregation, flotation, flocculation, screening or their
combinations. The separating device may be reactor, vessel, tank,
bowl, cyclone, column, cell, basin, thickener or the like.
[0033] In one embodiment, the lignin particle fraction (4) and
lignocellulose particle fraction (3) are separated in one
separation step (2,8,9,10). In one embodiment, the lignin particle
fraction (4) and lignocellulose particle fraction (3) are separated
in more than one separation step (2,8,9,10).
[0034] In one embodiment, the lignin particle fraction (4) and
lignocellulose particle fraction (3) are separated from each other
in the first separation step (2). In one embodiment, the first
separation step is an initial separation, such as rougher
separation step. The first separation step for separating the
lignocellulose particle fraction and lignin particle fraction is
made by means of centrifugal forces, e.g. by basket centrifuge or
decanter centrifuge such as solid bowl centrifuge, or flotation,
e.g. by froth flotation or column flotation. In flotation,
stabilized lignocellulose particles remain in suspension while free
lignin particles are raised by air bubbles to surface and then
either scraped or collected as overflow.
[0035] In one embodiment, the lignocellulose particle fraction (3)
is separated from the lignin particle fraction (4) as a clarifying
fraction, e.g. as an overflow of the thickener, in the separation
step (2, 8,9,10).
[0036] The lignocellulose particle fraction (3) may contain also
other components or agents than lignocellulose particles. In one
embodiment, the lignocellulose particle fraction (3) is treated,
preferably after the first separation step (2), by purifying in at
least one separation step (8) which may be selected from the
separation methods described above. In one embodiment, the
lignocellulose particle fraction (3) is treated, preferably
purified, in at least one scavenger separation step. In one
embodiment, the lignocellulose particle fraction (3) is treated in
two scavenger separation steps. If needed, these purifying steps
can be incorporated to recover remaining lignin particles from
lignocellulose particle fraction.
[0037] In one embodiment, the lignocellulose particle fraction (3)
is in the form of suspension. This suspension contains liquid, such
as water. In one embodiment, the lignocellulose particle fraction
is thickened. If needed, the lignocellulose particle fraction can
be thickened by dosing cationic flocculant, e.g. cationic
polyacrylamide, followed by centrifuge, thickener or cyclone.
Utilization in other applications generally involves further
dewatering, e.g. by filter or screw press, followed by drying.
[0038] In one embodiment, the lignocellulose particle fraction (3)
is dewatered, e.g. by a screw press. In one embodiment, the
lignocellulose particle fraction (3) is ground.
[0039] In one embodiment, the lignocellulose particle fraction (3)
is circulated (7) back to manufacturing process of the crude
lignin, e.g. to hydrolysis process (5). Alternatively, the
lignocellulose particle fraction (3) is circulated to a separate
hydrolysis process. Liquid in the lignocellulose particle fraction
replaces partly or totally fresh water needed in dilution of
biomass particles prior to hydrolysis. In one embodiment, the
apparatus comprises a circulations means for circulating (7) the
lignocellulose particle fraction (3) back to manufacturing process
of the crude lignin.
[0040] In one embodiment, the lignin particle fraction (4) is
sediment, sludge, residuum or deposit of the separation step. In
one embodiment, the lignin particle fraction (4) is removed as an
underflow of separating device, e.g. thickener, in the separation
step (2,8,9,10).
[0041] The lignin particle fraction (4) may contain also other
components or agents than lignin particles. In one embodiment, the
lignin particle fraction (4) is treated, preferably after the first
separation step (2), by purifying in at least one separation step
(9,10) which may be selected from the separation methods described
above. In one embodiment, the lignin particle fraction (4) is
treated, preferably purified, in at least one cleaning separation
step. In one embodiment, the lignin particle fraction (4) is
treated in two cleaning separation steps. In one embodiment, the
lignin particle fraction is treated in the cleaning separation step
by means of centrifugal cleaning e.g. by hydrocyclone,
sedimentation, e.g. by thickener, elutriation, aggregation,
flotation, flocculation and/or screening. In one embodiment, the
lignin particle fraction is removed from the cleaning separation
step as an underflow or as a sediment, sludge, residuum or
deposit.
[0042] In one embodiment, the lignin particle fraction (4) is
washed. The purified lignin can be easily neutralized in washing
stage without negatively affecting dewatering performance.
[0043] One benefit of this kind of separation process is that it
tolerates presence of soluble oligomeric sugars in the lignin
residue. Typically, if the lignin residue is not carefully washed
there are oligomeric sugars present, which make filtration
extremely complicated due to clogging tendency. In the present
invention, the filtration is only performed for the final lignin
particle fraction, which is washed and, therefore, contains no
oligomeric sugars. Oligomeric sugars may be carried over with the
lignocellulose particle fraction back to hydrolysis process. This
procedure enables savings in dewatering and washing of the lignin
residue, and also leads to higher sugar concentration in the
hydrolysate. If there is a process without washing the lignin
residue, then present invention demonstrates improved sugar
yield.
[0044] In one embodiment, the lignin particle fraction (4) is
filtrated, e.g. by a pressure filter. In one embodiment, the lignin
particle fraction (4) is dewatered. In one embodiment, the lignin
particle fraction (4) is treated by grinding.
[0045] In one embodiment, the apparatus comprises at least one
dewatering device for dewatering the lignin particle fraction (4)
or the lignocellulose particle fraction (3).
[0046] Improvement in dewatering of the lignin is important for the
present invention. Removal of the lignocellulose particles clearly
improves dewatering of the lignin. This means that less energy is
needed in drying, and often investment in dryer can be neglected
totally, if the purified lignin is burnt or used in applications
not requiring low moisture content. Size of free lignin particles
after hydrolysis is generally big, e.g. d50 over 10 .mu.m, as
compared to precipitated lignin particle meaning higher filtration
rate and dry solids content of filter cake.
[0047] The process of the present invention minimizes waste water
and often totally closed loop can be achieved. Clean water is added
only in a final stage of the lignin purification. With suitable
consistency of the lignocellulose particle fraction incoming and
outgoing flows are in balance without additional flow to waste
water treatment plant. The lignin is not dis-solved in any stage
preventing formation of low molecular weight phenolic compounds,
which would otherwise complicates circulation or disposal of
filtrates and overflows.
[0048] According to present invention a lignin particle composition
can be formed. The lignin particle composition includes lignin
particle fraction of the crude lignin in which the crude lignin has
been formed from starting material and the crude lignin comprises
lignocellulose particles and lignin particles, and the lignin
particle fraction has been formed from the crude lignin by adding
stabilizing chemical and/or hydrophobic chemical into the crude
lignin, and by separating the lignocellulose particle fraction from
the lignin particle fraction in at least one separation step. The
lignin particle composition may be used as component in
manufacturing a final product selected from the group consisting of
activated carbon, carbon fiber, lignin composite, binder material,
resins, phenolic component and/or dispersion agent. In one
embodiment, the lignin particle composition is used as an
ad-sorbent for oil or heavy metals. In one embodiment, the lignin
particle composition is used as combustible matter in energy
production.
[0049] According to present invention a lignocellulose particle
composition can be formed. The lignocellulose particle composition
includes lignocellulose particle fraction of the crude lignin in
which the crude lignin has been formed from starting material and
the crude lignin comprises lignocellulose particles and lignin
particles, and the lignocellulose particle fraction has been formed
from the crude lignin by adding stabilizing chemical and/or
hydrophobic chemical into the crude lignin, and by separating the
lignocellulose particle fraction from the lignin particle fraction
in at least one separation step. The lignocellulose particle
composition may be used as component in manufacturing a product
selected from the group consisting of composites, wood composites,
wood-plastic composites comprising composites formed from plastic,
synthetic polymers, biopolymers, rubber or their combinations
together with wood, resins, preferably as filler in resins, wood
based materials, wood based fillers, construction materials,
building boards, glue boards and/or other wood based boards, such
as a particle board, an oriented strand board, a chip board, an
intrallam, a gluelam, a hardboard, a waferboard, a fiber board or a
plywood. In one embodiment, the lignocellulose particle composition
is used as combustible matter in energy production.
[0050] The method according to the present invention provides the
lignin particle composition and the lignocellulose particle
composition with good quality. When improving the purify and
increasing dry solids content of the lignin and lignocellulose
compositions so then it may be provided better properties of the
final product. Thanks to the invention, preferably improved
filterability is achieved. Further, by means of the invention
dewatering can be improved. Preferably, treating costs of the
lignin can be decreased. Further, thanks to the invention heat
value of the lignin and lignocellulose compositions can be
increased so that the heat value without drying may even at least
be duplicated.
[0051] The present invention provides an industrially applicable,
simple and affordable way of making the purified lignin based
composition and lignocellulose composition from the starting
material. The method according to the present invention is easy and
simple to realize as a production process. The method according to
the present invention is suitable for use in the manufacture of the
different lignin and lignocellulose based products and final
products from different starting materials. In one embodiment, the
crude lignin is purified from the lignocellulose particles.
Further, the lignin and lignocellulose compositions can be used as
sources of energy.
EXAMPLES
[0052] The invention is described in more detail by the following
examples with reference to accompanying drawings.
Example 1
[0053] In this example a lignocellulose particle fraction (3) and
lignin particle fraction (4) are separated according to a process
of FIG. 1.
[0054] The crude lignin (1) is formed from starting material (6)
comprises lignocellulose particles and lignin particles by means of
hydrolysis (5). The crude lignin (1) is fed into the separation
step (2) wherein stabilizing chemical (11) and/or hydrophobic
chemical (12) are fed into the crude lignin (1). The lignocellulose
particle fraction (3) is separated from the crude lignin so that
remaining crude lignin is the lignin particle fraction (4), i.e.
the purified crude lignin. Alternatively, the lignocellulose
particle fraction (3) may be circulated back to the manufacture of
the crude lignin.
Example 2
[0055] In this example a lignocellulose particle fraction (3) and
lignin particle fraction (4) are separated according to a process
of FIG. 2.
[0056] The crude lignin (1) is formed from starting material (6)
comprises lignocellulose particles and lignin particles by means of
hydrolysis (5). The crude lignin (1) is fed into the first
separation step (2) wherein stabilizing chemical (11) and/or
hydrophobic chemical (12) are fed into the crude lignin (1). The
lignocellulose particle fraction (3) is separated from the crude
lignin, and the separated lignocellulose particle fraction (3) is
purified in the additional separation step (8). Stabilizing
chemical (11) and/or hydrophobic chemical (12) may be added in the
additional separation step (8). The remaining crude lignin residuum
is purified in the additional separation step (9) in order to form
the lignin particle fraction (4), i.e. the purified crude lignin.
Stabilizing chemical (11) and/or hydrophobic chemical (12) may be
added in the additional separation step (9). In an alternative
embodiment, the stabilizing chemical (11) and/or hydrophobic
chemical (12) are added only into the fraction of the crude lignin,
such as the lignocellulose particle fraction and/or remaining crude
lignin residuum, in the additional separation step (8) and/or
additional separation step (9) after the first separation step
(2).
[0057] Alternatively, the lignocellulose particle fraction (3) may
be circulated back to the manufacture of the crude lignin.
Example 3
[0058] In this example a lignocellulose particle fraction (3) and
lignin particle fraction (4) are separated according to a process
of FIG. 3.
[0059] The crude lignin (1) is formed from starting material (6)
comprises lignocellulose particles and lignin particles by means of
hydrolysis (5). The crude lignin (1) is fed into the first
separation step (2) wherein stabilizing chemical (11) and/or
hydrophobic chemical (12) are fed into the crude lignin (1). The
lignocellulose particle fraction (3) is separated from the crude
lignin. The remaining crude lignin residuum is purified in the
second (9) and third (10) separation steps in order to form the
lignin particle fraction (4), i.e. the purified crude lignin.
Stabilizing chemical (11) and/or hydrophobic chemical (12) may be
added in the second (9) and/or third (10) separation steps.
Alternatively, the lignocellulose particle fraction (3) may be
circulated back to the manufacture of the crude lignin.
Example 4
[0060] In this example, lignin (4) was purified and lignocellulose
(3) was separated from the crude lignin (1) according to FIG.
4.
[0061] The crude lignin (1) analyzed to contain 63.3%
acid-insoluble lignin, 3.4% acid-soluble lignin, 35.8% glucose and
36.3% total carbohydrates was re-slurried with water (14). Slurry
was diluted (13) to 4% dry solids content and pH was 3.7.
Carboxymethyl cellulose (CMC) (11) was added 3.5 kg/t ds and
kerosene (12) was added simultaneously 4.5 kg/t ds followed by
high-shear mixing for 3 min. Rougher purification was performed
using Alfa Laval LAPX 404 separator (basket centrifuge) by feed
rate of 15 l/min at 50.degree. C. temperature in the first
separation step (2). After rougher stage sediment contained 88.2%
acid-insoluble lignin, 2.6% acid-soluble lignin and 8.3% glucose.
Lighter solid phase, i.e. lignocellulose fraction (3), contained
only 25.1% acid-insoluble lignin and 2.0% acid-soluble lignin
referring to efficient solid-solid separation. Great majority of
lignin present in lighter solid phase is bound into lignocellulose
particles.
[0062] The collected pre-cleaned lignin (15) was further cleaned in
two stages (9,10) utilizing sedimentation. Slurry was diluted to 5%
dry solids content with clean water (18). CMC (11) was added 1.0
kg/t ds and kerosene (12) was added simultaneously 1.4 kg/t ds
followed by high-shear mixing for 3 min. 800 ml of slurry was
sedimented for 10 min at 40'C temperature. Surprisingly, black
lignin particles rapidly settled, while brown lignocellulose
particles remained in suspension. Overflow (16) was decanted away
and black high-consistency (ds 50%) underflow (17) was further
cleaned in the third stage (10) in similar manner than in the
second stage (9) except that CMC (11) was now dosed 0.5 kg/t ds and
kerosene (12) was dosed 0.7 kg/t ds. Surprisingly, it was observed
that the separation of the lignin particles and lignocellulose
particles can be made successfully though there is only small
difference in density and size of said particles.
[0063] After purification lignin product (4) con-taming 94.3%
acid-insoluble lignin, 3.2% acid-soluble lignin and 2.7% glucose
was recovered.
Example 5
[0064] In this example, lignin (4) was purified and lignocellulose
(3) was separated from the crude lignin (1) according to a process
of FIG. 4.
[0065] The crude lignin (1) contained 97% particles smaller than
100 .mu.m as measured by screening. Median particle size was 20
.mu.m measured by Coulter LS laser diffraction analyzer.
[0066] The crude lignin (1) analyzed to contain 68.0%
acid-insoluble lignin, 1.9% acid-soluble lignin, 31.3% glucose and
31.8% total carbohydrates was re-slurried with water (14). Slurry
was diluted (13) to 3.5% dry solids content and pH was adjusted to
6.5 with NaOH. Carboxymethyl cellulose (CMC) (11) was added 4.5
kg/t ds followed by high-shear mixing for 3 min. Rougher
purification was performed using Alfa Laval LAPX 404 separator
(basket centrifuge) by feed rate of 15 l/min at 52.degree. C.
temperature in the first separation step (2). After rougher stage
sediment contained 85.1% acid-insoluble lignin, 1.8% acid-soluble
lignin and 12.7% glucose.
[0067] The collected pre-cleaned lignin (15) was further cleaned in
two stages (9,10) utilizing sedimentation. Slurry was diluted to 5%
dry solids content with clean water (18). CMC (11) was added 1.0
kg/t ds followed by high-shear mixing for 3 min. 800 ml of slurry
was sedimented for 10 min at 50.degree. C. temperature. Black
lignin particles rapidly settled, while brown lignocellulose
particles remained in suspension. Overflow (16) was decanted away
and black high-consistency underflow (17) was further cleaned in
the third stage (10) in similar manner than in the second stage (9)
except that CMC (11) was now dosed 0.5 kg/t ds.
[0068] After purification lignin product (4) containing 89.7%
acid-insoluble lignin, 1.4% acid-soluble lignin and 6.1% glucose
was recovered. In the cleaning stages recovery of underflow solids
was 50% of total solids.
[0069] As reference, test was repeated for crude lignin (1) without
addition of CMC (11) and without pH adjustment. After rougher stage
(2) sediment contained 82.0% acid-insoluble lignin, 1.8%
acid-soluble lignin and 17.8% glucose. During cleaning stages (9,
10) no aggregation or fast settling of free lignin particles was
noticed. Additionally, lignocellulose particles started to
destabilize, i.e. to settle. Similar mass of wet underflow was
collected as in test applying CMC. After purification lignin
product (4) containing 85.6% acid-insoluble lignin, 1.6%
acid-soluble lignin and 10.7% glucose was recovered. In the
cleaning stages recovery of underflow solids was only 8% of total
solids.
[0070] The results show that applying CMC as stabilizing agent
clearly improves selectivity of mechanical solid-solid separation
as compared to situation without any chemicals.
Example 6
[0071] In this example, the purified lignin product (4) formed
according to Example 3 was filtrated.
[0072] The purified crude lignin slurry (4) at pH 7.0 was filtrated
using horizontal 0.1 m.sup.2 plate pressure filter. As reference
crude lignin without purification was also filtrated. The crude
lignin in 40% dry solids content was re-slurried with clean water
to 14.4% ds before filtration, pH of filtrated slurry was 3.4. In
both cases compression stage was ended when filtrate flow lowered
to 15 ml/kg ds cake/min. Filtration temperature was 60-70.degree.
C. Results are shown in Table 1.
TABLE-US-00001 TABLE 1 Dry solids content Filtration rate Sample of
filter cake (%) (kg ds/m.sup.2/h) Crude lignin 48.4 1.3 Purified
lignin 81.3 564 Purified lignin 83.2 455
[0073] Filtration rate was calculated based on combination of feed,
compression and air blow (30 s) stages. Technical time was not
taken into account. Huge difference in filtration rates between the
purified and crude lignins is mostly caused by variation in
compression time. For the purified lignin 2-3 min at 15 bar was
enough, whereas 150 min at 15 bar was needed for the crude lignin.
Also amount of lignin filtrated per cycle is significantly higher
for the purified lignin. Exceptionally high dry solids content for
the purified lignin cake was demonstrated together with high
filtration rate in neutral conditions.
[0074] The method according to the present invention is suitable in
different embodiments to be used for separating the most different
kinds of lignocellulose particles from lignin particles.
[0075] The invention is not limited merely to the example referred
to above; instead many variations are possible within the scope of
the inventive idea de-fined by the claims.
* * * * *