U.S. patent application number 16/661490 was filed with the patent office on 2020-03-05 for processing biomass.
The applicant listed for this patent is XYLECO, INC.. Invention is credited to Thomas Craig MASTERMAN, Marshall MEDOFF, Robert PARADIS.
Application Number | 20200070120 16/661490 |
Document ID | / |
Family ID | 50477883 |
Filed Date | 2020-03-05 |
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United States Patent
Application |
20200070120 |
Kind Code |
A1 |
MEDOFF; Marshall ; et
al. |
March 5, 2020 |
PROCESSING BIOMASS
Abstract
Methods and systems are described for processing cellulosic and
lignocellulosic materials into useful intermediates and products,
such as energy and fuels. For example, conveying systems and
methods, such as highly efficient vibratory conveyors, are
described for the processing of the cellulosic and lignocellulosic
materials.
Inventors: |
MEDOFF; Marshall;
(Wakefield, MA) ; MASTERMAN; Thomas Craig;
(Rockport, MA) ; PARADIS; Robert; (Burlington,
MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
XYLECO, INC. |
Wakefield |
MA |
US |
|
|
Family ID: |
50477883 |
Appl. No.: |
16/661490 |
Filed: |
October 23, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16177669 |
Nov 1, 2018 |
10500561 |
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16661490 |
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15384126 |
Dec 19, 2016 |
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16177669 |
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14242221 |
Apr 1, 2014 |
9556496 |
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15384126 |
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PCT/US2013/006428 |
Oct 10, 2013 |
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14242221 |
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61793336 |
Mar 15, 2013 |
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61774731 |
Mar 8, 2013 |
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61774735 |
Mar 8, 2013 |
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61774740 |
Mar 8, 2013 |
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61774744 |
Mar 8, 2013 |
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61774723 |
Mar 8, 2013 |
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61774684 |
Mar 8, 2013 |
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61774746 |
Mar 8, 2013 |
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61774780 |
Mar 8, 2013 |
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61774750 |
Mar 8, 2013 |
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61774752 |
Mar 8, 2013 |
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61774754 |
Mar 8, 2013 |
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61774761 |
Mar 8, 2013 |
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61774773 |
Mar 8, 2013 |
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61774775 |
Mar 8, 2013 |
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61711801 |
Oct 10, 2012 |
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61711807 |
Oct 10, 2012 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
Y02E 50/16 20130101;
C10L 5/442 20130101; Y02E 50/32 20130101; H01J 37/317 20130101;
D21B 1/02 20130101; B01J 2219/0869 20130101; H01J 2237/202
20130101; C10L 2290/28 20130101; B01J 2219/1203 20130101; C10B
19/00 20130101; C10L 5/46 20130101; Y02E 50/30 20130101; A61L 2/087
20130101; B01J 19/085 20130101; B01J 19/123 20130101; C10B 53/02
20130101; C08H 8/00 20130101; C10L 2200/0469 20130101; H01J 5/18
20130101; C10G 32/04 20130101; C10L 2290/36 20130101; G21F 3/00
20130101; B65G 27/04 20130101; Y02E 50/17 20130101; B01J 19/12
20130101; C12P 7/10 20130101; B01J 2219/0871 20130101; B01J
2219/0879 20130101; C10G 1/02 20130101; Y02E 50/14 20130101; B01J
19/125 20130101; C10L 2290/52 20130101; G21K 5/04 20130101; H01J
2237/2002 20130101; H01J 37/20 20130101; B01J 2219/12 20130101;
C10L 5/445 20130101; C12P 2201/00 20130101; C10L 2290/24 20130101;
C13K 13/002 20130101; Y02P 60/877 20151101; H01J 33/04 20130101;
Y02P 60/87 20151101; G21K 5/10 20130101; C10L 5/403 20130101; C13K
1/02 20130101; B01J 19/082 20130101; Y02P 20/145 20151101; B01J
19/22 20130101; Y02E 50/10 20130101 |
International
Class: |
B01J 19/08 20060101
B01J019/08; C12P 7/10 20060101 C12P007/10; C10L 5/46 20060101
C10L005/46; C10L 5/40 20060101 C10L005/40; H01J 33/04 20060101
H01J033/04; C13K 13/00 20060101 C13K013/00; C13K 1/02 20060101
C13K001/02; B65G 27/04 20060101 B65G027/04; H01J 37/20 20060101
H01J037/20; D21B 1/02 20060101 D21B001/02; H01J 37/317 20060101
H01J037/317; G21F 3/00 20060101 G21F003/00; H01J 5/18 20060101
H01J005/18; G21K 5/10 20060101 G21K005/10; G21K 5/04 20060101
G21K005/04; B01J 19/22 20060101 B01J019/22; B01J 19/12 20060101
B01J019/12; A61L 2/08 20060101 A61L002/08; C10L 5/44 20060101
C10L005/44; C08H 8/00 20060101 C08H008/00; C10B 19/00 20060101
C10B019/00; C10G 1/02 20060101 C10G001/02; C10B 53/02 20060101
C10B053/02; C10G 32/04 20060101 C10G032/04 |
Claims
1. A method comprising: depositing a biomass material, in
particulate form, on a trough of a vibratory conveyor; vibrating
the vibratory conveyor and cooling the biomass material, while
conveying the biomass material; and exposing the biomass material
on the vibratory conveyor to ionizing radiation in the form of at
least one electron beam through at least one corresponding opening
in the conveyor cover.
2. The method of claim 1, wherein cooling the biomass material
comprises cooling the trough.
3. The method of claim 1, further comprising comminuting the
biomass prior to exposing the biomass to the ionizing
radiation.
4. The method of claim 3, wherein comminuting is selected from the
group consisting of shearing, chopping, grinding, hammermilling and
combinations thereof.
5. The method of claim 3, wherein comminuting produces a biomass
material with particles, and more than 80% of the particles have at
least one dimension that is less than about 0.25 inches.
6. The method of claim 3, wherein comminuting produces a biomass
material with particles, and no more than 5% of the particles are
less than 0.03 inches in their greatest dimension.
7. The method of claim 1, wherein the biomass is irradiated with 10
to 200 Mrad of radiation.
8. The method of claim 1, wherein the biomass is exposed to more
than one dose of radiation utilizing multiple accelerating heads to
expose the biomass to a plurality of scanning electron beams while
the biomass is being conveyed on the vibratory conveyor, each
scanning electron beam being delivered through a corresponding
opening in the cover.
9. The method of claim 1, wherein the biomass material comprises
cellulosic or lignocellulosic material.
10. The method of claim 9, wherein the cellulosic or
lignocellulosic material comprises a lignocellulosic material
selected from the group consisting of wood, paper, paper products,
cotton, grasses, grain residues, bagasse, jute, hemp, flax, bamboo,
sisal, abaca, corn cobs, corn stover, coconut hair, algae, seaweed,
straw, wheat straw and mixtures thereof.
11. The method of claim 1, wherein the vibratory conveyor has a
covering that includes an opening through which the electron beam
is directed.
12. The method of claim 1, wherein the opening in the cover
includes a window foil that allows passage of the ionizing
radiation through the window foil and onto the biomass
material.
13. The method of claim 1, wherein the biomass material is conveyed
at a rate of at least about 1000 lb/hr.
14. The method of claim 1, wherein the spreader comprises a drop
spreader.
15. The method of claim 1, wherein the energy of the electron beam
is from about 0.3 to 2 MeV.
16. The method of claim 1, wherein the vibratory conveyor conveys
the biomass material at an average speed of from about 3 to 100
ft/min.
17. The method of claim 1, wherein the material is deposited using
a spreader.
18. The method of claim 17, wherein when it is deposited the
biomass material covers only a portion of a width of the trough,
and during conveying the biomass material spreads out to cover
substantially the entire width of the trough.
19. The method of claim 1, wherein the electron beam is a scanning
electron beam
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 16/177,669, filed Nov. 1, 2018, which is a
continuation of U.S. application Ser. No. 15/384,126, filed Dec.
19, 2016, now abandoned, which is a continuation of U.S.
application Ser. No. 14/242,221, filed Apr. 1, 2014, now U.S. Pat.
No. 9,556,496, issued on Jan. 31, 2017, which is a continuation of
PCT/US13/64289 filed Oct. 10, 2013, which claims priority to the
following provisional applications: U.S. Ser. No. 61/711,807, filed
Oct. 10, 2012; U.S. Ser. No. 61/711,801, filed Oct. 10, 2012; U.S.
Ser. No. 61/774,684, filed Mar. 8, 2013; U.S. Ser. No. 61/774,773,
filed Mar. 8, 2013; U.S. Ser. No. 61/774,731, filed Mar. 8, 2013;
U.S. Ser. No. 61/774,735, filed Mar. 8, 2013; U.S. Ser. No.
61/774,740, filed Mar. 8, 2013; U.S. Ser. No. 61/774,744, filed
Mar. 8, 2013; U.S. Ser. No. 61/774,746, filed Mar. 8, 2013; U.S.
Ser. No. 61/774,750, filed Mar. 8, 2013; U.S. Ser. No. 61/774,752,
filed Mar. 8, 2013; U.S. Ser. No. 61/774,754, filed Mar. 8, 2013;
U.S. Ser. No. 61/774,775, filed Mar. 8, 2013; U.S. Ser. No.
61/774,780, filed Mar. 8, 2013; U.S. Ser. No. 61/774,761, filed
Mar. 8, 2013; U.S. Ser. No. 61/774,723, filed Mar. 8, 2013; and
U.S. Ser. No. 61/793,336, filed Mar. 15, 2013. The entire
disclosure of each of these applications are incorporated by
reference herein.
BACKGROUND
[0002] As demand for petroleum increases, so too does interest in
renewable feedstocks for manufacturing biofuels and biochemicals.
The use of lignocellulosic biomass as a feedstock for such
manufacturing processes has been studied since the 1970s.
Lignocellulosic biomass is attractive because it is abundant,
renewable, domestically produced, and does not compete with food
industry uses.
[0003] Many potential lignocellulosic feedstocks are available
today, including agricultural residues, woody biomass, municipal
waste, oilseeds/cakes and sea weeds, to name a few. At present
these materials are either used as animal feed, biocompost
materials or are burned in a cogeneration facility or are
landfilled.
[0004] Lignocellulosic biomass comprises crystalline cellulose
fibrils embedded in a hemicellulose matrix, surrounded by lignin.
This produces a compact matrix that is difficult to access by
enzymes and other chemical, biochemical and biological processes.
Cellulosic biomass materials (e.g., biomass material from which the
lignin has been removed) is more accessible to enzymes and other
conversion processes, but even so, naturally-occurring cellulosic
materials often have low yields (relative to theoretical yields)
when contacted with hydrolyzing enzymes. Lignocellulosic biomass is
even more recalcitrant to enzyme attack. Furthermore, each type of
lignocellulosic biomass has its own specific composition of
cellulose, hemicellulose and lignin.
[0005] While a number of methods have been tried to extract
structural carbohydrates from lignocellulosic biomass, they are
either are too expensive, produce too low a yield, leave
undesirable chemicals in the resulting product, or simply degrade
the sugars.
[0006] Monosaccharides from renewable biomass sources could become
the basis of chemical and fuels industries by replacing,
supplementing or substituting petroleum and other fossil
feedstocks. However, techniques need to be developed that will make
these monosaccharides available in large quantities and at
acceptable purities and prices.
SUMMARY OF THE INVENTION
[0007] Disclosed are methods and systems for conveying carbohydrate
containing materials prior to, during and/or after processing. In
particular, methods for conveying the material using one or more
vibratory conveyors are disclosed.
[0008] Provided herein are methods of producing a treated biomass
material, where the methods include: providing a starting biomass
material; conveying the starting biomass material upon a vibratory
conveyor; and exposing the starting biomass material to ionizing
radiation while the biomass is being conveyed upon the vibratory
conveyer; thereby producing a treated biomass material. Optionally,
the biomass defines a substantially uniform thickness bed on the
conveyor as it is being exposed to the ionizing radiation. The
method can further include distributing the biomass material prior
to conveying the biomass material upon the vibratory conveyor and
exposing the biomass to ionizing radiation.
[0009] Also provided herein is an apparatus for producing a treated
biomass material, which includes: an ionizing radiation source; and
a vibratory conveying system, wherein the vibratory conveying
system is capable of conveying biomass past the ionizing radiation
source.
[0010] The apparatus can also include an enclosure surrounding the
biomass when it is proximate to the radiation source. The enclosure
can include a window foil integrated into a wall of the enclosure,
and wherein the window foil is disposed beneath the radiation
source and allows passage of the electrons through the window foil
and onto the biomass. The apparatus and methods can further include
a feeder conveying system upstream from the vibratory conveying
system, wherein the feeder conveying system feeds the biomass to
the vibratory conveying system upstream of the radiation field. The
feeder conveying system can also be a vibratory conveying system.
One or both of the conveying systems can convey the biomass at an
average speed of 3 to 100 ft/min, at an average speed of 9 to 50
ft/min, or at an average speed of 10 to 25 ft/min.
[0011] The feeder conveying system can be used to distribute the
biomass material onto a bed of substantially uniform thickness. For
example, seventy-five percent (75%) or more of the biomass material
can be at the average bed thickness, or 80%, 85%, 90%, 95% or more
of the biomass material can be at the average bed thickness.
[0012] The biomass in the methods and apparatus can be comminuted
prior to being exposed to the ionizing radiation. The type of
comminution can be selected from the group consisting of: shearing,
chopping, grinding, hammermilling or more than one of these. The
comminution can produce a starting biomass material with particles,
where greater than 80% or 85% of the particles have at least one
dimension that is less than about 0.25 inches, where greater than
90% of the particles have at least one dimension that is less than
about 0.25 inches, or where greater than 91%, 92%, 93%, 94%, 95%,
96%, 97%, 98% or 99% of the particles have at least one dimension
that is less than about 0.25 inches. The comminution can produce a
starting biomass where no more than 5% of the particles are less
than 0.03 inches in their greatest dimension, where no more than 5%
of the particles are less than 0.02 inches in their greatest
dimension or where no more than 5% of the particles are less than
0.01 inches in their greatest dimension.
[0013] In the methods and apparatus, the source of the ionizing
radiation can be an electron beam, an ion beam, ultraviolet light
with a wavelength of between 100 nm and 280 nm, gamma radiation,
X-ray radiation or combinations thereof. An electron beam is
preferred.
[0014] The biomass can be irradiated with 10 to 200 Mrad of
radiation, with 10 to 75 Mrad of radiation, with 10 to 15 Mrad of
radiation, with 15 to 50 Mrad of radiation or with 20 to 35 Mrad of
radiation. The biomass can be subjected to multiple rounds of
irradiation. For example, the biomass can optionally be conveyed
multiple times under a beam of ionizing radiation (e.g., 1, 2, 3, 4
or even more times). For, example, each irradiation increasing
total dosage of irradiation to the material with optional cooling
between irradiations.
[0015] The energy of the electron beam can be between 0.3 and 2
MeV, or between 0.5 and 10 MeV, between 0.8 and 5 MeV, between 0.8
and 3 MeV, between 1 and 3 MeV, and about 1 MeV.
[0016] In some implementations of the methods or apparatus the
biomass material is irradiated with an irradiating device with a
power output of at least 50 kW (e.g., at least 75 kW, at least 100,
at least 125, at least 500 kW).
[0017] In some implementation of the methods or systems, the
biomass material is conveyed at a rate of about 1000 to about 8000
lb/hr (e.g., between about 2000 and 5000 lb/hr) using the vibratory
conveyors. Optionally the conveyors can be made using structural
materials that include steel such as stainless steel (e.g., 304 or
316 L steel). Optionally the conveyors include anti-stick coatings.
For example, the conveyor can include a trough made of stainless
steel.
[0018] In the methods and apparatus provided herein, the electron
beam can be supplied by an electron accelerator equipped with a
scanning horn disposed above the conveyor and configured to direct
the electron beam onto the biomass upon the vibratory conveyor.
[0019] The biomass material can receive a substantially uniform
level of irradiation. The treated biomass material can exhibit a
lower level of recalcitrance relative to the starting biomass
material.
[0020] The starting biomass material can include a cellulosic or
lignocellulosic material, such as wood, paper, paper products,
cotton, grasses, grain residues, bagasse, jute, hemp, flax, bamboo,
sisal, abaca, corn cobs, corn stover, coconut hair, algae, seaweed,
straw, wheat straw or mixtures thereof.
[0021] In the methods and apparatus provided herein, at least a
portion of the conveyor can include an enclosure.
[0022] A vibratory conveyor can provide an efficient mode of
conveying biomass material under an irradiation source. The
oscillating motions in all the possible combinations of x, y and z
directions (where x is the direction of conveying, y is transverse
to the direction of conveying, and z is in the direction
perpendicular to conveying and orthogonal to x and y) for example,
in the x direction, in x+z, and/or in x+y+z, provide many
advantages while allowing conveying at a constant speed. The method
and systems described can also provide an efficient mode of
spreading out biomass material (for example, without additional
spreading equipment or with fewer burdens on the optional spreading
equipment) to an even thickness so that the irradiation can be
substantially uniform. A further advantage over some other
conveying systems and methods is that the biomass is turned and
rotated, improving the irradiation uniformity, dosage averaging and
cooling of the biomass. The uniform irradiation and improved dosage
averaging can provide a material that has reduced recalcitrance
throughout its bulk. Also, vibratory conveyors, for example, in
comparison to other conveying systems and methods, can be lower in
cost to operate. The methods and systems described herein can also
reduce the intensity of irradiation needed to irradiate through the
bulk of a biomass and reduce costs and increase safety of used,
e.g., by reducing the shielding that is required.
[0023] Implementations of the invention can optionally include one
or more of the following summarized features. In some
implementations, the selected features can be applied or utilized
in any order while in others implementations a specific selected
sequence is applied or utilized. Individual features can be applied
or utilized more than once in any sequence. In addition, an entire
sequence, or a portion of a sequence, of applied or utilized
features can be applied or utilized once or repeatedly in any
order. In some optional implementations, the features can be
applied or utilized with different, or where applicable the same,
set or varied, quantitative or qualitative parameters as determined
by a person skilled in the art. For example, parameters of the
features such as size, individual dimensions (e.g., length, width,
height), location of, degree (e.g., to what extent such as the
degree of recalcitrance), duration, frequency of use, density,
concentration, intensity and speed can be varied or set, where
applicable as determined by a person of skill in the art.
[0024] Features, for example, include: a method for exposing a
biomass material to ionizing radiation while the biomass material
is being conveyed upon a vibratory conveyor; the biomass material
defines a substantially uniform thickness bed on the conveyor as it
is being exposed to the ionizing radiation; distributing the
biomass material prior to conveying the biomass material upon the
vibratory conveyer and exposing the biomass to the ionizing
radiation; distributing the biomass material utilizes a feeder
conveying system; the feeder conveying system comprises a second
vibratory conveying system; seventy five percent or more of the
biomass material is distributed to be at the level of the average
bed thickness; eighty five percent or more of the biomass material
is distributed to be at the level of the average bed thickness;
ninety percent or more of the biomass material is distributed to be
at the level of the average bed thickness; ninety five percent or
more of the biomass material is distributed to be at the level of
the average bed thickness; comminuting the biomass prior to
exposing the biomass to the ionizing radiation; comminuting
consists of shearing; comminuting consists chopping; comminuting
consists of grinding; comminuting consists of hammermilling;
comminuting produces a biomass material with particles; comminuting
produces a biomass material wherein greater than 80% of the
particles have at least one dimension that is less than about 0.25
inches; comminuting produces a biomass material wherein greater
than 90% of the particles have at least one dimension that is less
than about 0.25 inches; comminuting produces a biomass material
wherein greater than 95% of the particles have at least one
dimension that is less than about 0.25 inches; comminuting produces
a biomass material wherein no more than 5% of the particles are
less than 0.03 inches in their greatest dimension; the source of
the ionizing is an electron beam; the source of the ionizing is an
ion beam; the source of the ionizing is ultraviolet light with a
wavelength of between 100 nm and 280 nm; the source of the ionizing
is gamma radiation; The source of the ionizing is X-ray radiation;
the biomass is irradiated with 10 to 200 Mrad of radiation; the
biomass is irradiated with 10 to 25 Mrad of radiation; the biomass
is irradiated with 10 to 75 Mrad of radiation; the biomass is
irradiated with 15 to 50 Mrad of radiation; the biomass is
irradiated with 20 to 35 Mrad of radiation; the energy of the
electron beam is between 0.3 and 2 MeV; the electron beam is
supplied by an electron accelerator equipped with a scanning horn
disposed above the conveyor and configured to direct the electron
beam onto the biomass upon the vibratory conveyor; the biomass
material receives a substantially uniform level of ionizing
radiation; the biomass material comprises a cellulosic or
lignocellulosic material; The biomass material includes wood; The
biomass material includes paper; the biomass material includes wood
paper products; the biomass material includes cotton; the biomass
material includes grasses; the biomass material includes grain
residues; the biomass material includes bagasse; the biomass
material includes jute; the biomass material includes hemp; the
biomass material includes flax; the biomass material includes
bamboo; the biomass material includes sisal; the biomass material
includes abaca; the biomass material includes corn cobs; the
biomass material includes corn stover; the biomass material
includes coconut hair; the biomass material includes algae; the
biomass material includes seaweed; the biomass material includes
straw; the biomass material includes wheat straw; at least a
portion of the conveyor comprises an enclosure; exposing the
biomass material to ionizing radiation reduces the recalcitrance of
the biomass material; the vibratory conveyer conveys the biomass
material at an average speed of 3 to 100 ft/min; the vibratory
conveyer conveys the biomass material at an average speed of 9 to
50 ft/min; the vibratory conveyer conveys the biomass material at
an average speed of 12 to 25 ft/min; the biomass material is
irradiated with an irradiator with a power output of at least 50
kW; the biomass material is conveyed at a rate of about 1000 to
about 8000 lb/hr: the biomass is exposed to ionizing radiation more
than one time.
[0025] Some other features, for example, include: an apparatus for
producing a treated biomass material including an ionizing
radiation source and a vibratory conveyor system, wherein the
vibratory conveyor system is capable of conveying biomass material
past the ionizing radiation source; an enclosure surrounding the
biomass material when the biomass material is proximate to a
radiation source; the enclosure comprises a window foil integrated
into a wall of the enclosure, and wherein the window foil is
disposed beneath the radiation source and allows passage of the
electrons through the window foil and onto the biomass material; a
feeder conveying system upstream from the vibratory conveying
system, wherein the feeder conveying system is configured to spread
the biomass material to form a bed of biomass material of
substantially uniform depth, and where the feeder conveying system
feeds the biomass material to the vibratory conveying system
upstream of the radiation field; the feeder conveying system is a
vibratory conveying system; the conveyor system comprises
structural materials including steel.
[0026] Other features and advantages will be apparent from the
following detailed description, and from the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1A is a side view of a system for treating a biomass.
FIG. 1B is a top view of a system for treating a biomass. FIG. 1C
is a detailed view of an irradiation zone. FIG. 1D is a right side
view of a system for treating a biomass. FIG. 1E is a front side
detail view of a window system of a system for treating
biomass.
[0028] FIG. 2 is a flow diagram illustrating conversion of a
biomass feedstock to one or more products.
[0029] FIG. 3A is a diagram illustrating, by exaggeration, the
movement of a particulate biomass on a first type of vibratory
conveyor. FIG. 3B is a diagram illustrating, by exaggeration, the
movement of a particulate biomass on a second type of vibratory
conveyor. FIG. 3C is a diagram illustrating, by exaggeration, the
movement of a particulate biomass on a third type of vibratory
conveyor.
[0030] FIG. 4 is a perspective view of a vibratory conveyor.
[0031] FIG. 5 is a perspective view of a vibratory conveyor with a
cover.
[0032] FIG. 6A is a perspective view of a vibratory conveyor. FIG.
6B is a side view of a vibratory conveyor.
[0033] FIG. 7 is a flow diagram showing a process for treating
biomass.
DETAILED DESCRIPTION
[0034] Provided herein are methods and apparatus for producing a
treated biomass material with a vibratory conveyer. The methods and
apparatus provide an advantage because the vibratory conveyor
provides an efficient mode of conveying biomass material while it
is under an irradiation source.
[0035] An exemplary embodiment is shown in FIGS. 1A-1E. FIG. 1A
shows a front side view of a system for irradiation of particulate
biomass. A spreader, for example, a distributer such as a CHRISTY
SPREADER.TM. 110 containing a biomass drops a controlled stream of
biomass 112 onto the trough of a covered vibratory conveyor 113
through an opening 114 in the cover of the conveyor. This aids in
providing a substantially uniform thickness of the material spread
across the conveyer. The covered vibratory conveyor is supported by
a support 184 and includes a transverse vibration system including
leaf springs. The transverse drive assembly 186 provides horizontal
oscillating movement to the trough. The drive motor includes an
eccentric crank 198. The biomass is conveyed in the direction of
the shown arrows (downstream to upstream) through a scanning
electron beam 116 generated by an electron beam irradiation device
with an accelerating tube 118 and a scanning horn 120. The electron
beam is extracted from the high vacuum side of the scan horn
through a window foil, passes through an air gap, through a window
mounted in the cover 115, and irradiates the material 178 being
conveyed beneath. The irradiated material is then conveyed away
from the irradiation area and drops into a collecting hopper 122.
In preferred embodiments at least the irradiation zone (e.g., the
region where the irradiation takes place) is in a vault, and
optionally the entire vibratory conveyor and hoppers, for example,
as outlined by the dotted line in FIG. 1A 192, can be in a vault.
The biomass can enter via ingress 188 and egress 190
respectively.
[0036] In the embodiment above, as shown schematically as a top
view of the conveyor surface by FIG. 1B, the area covered by the
biomass below the opening of the hopper 124 is a small
approximately rectangular area compared to the width of the trough,
its size being primarily determined by the size and shape of the
spreader opening and the vertical drop from the opening of the
hopper to the trough surface. In some embodiments the opening width
of the spreader is about the same as the width of the conveyor or
it can be smaller than the width of the conveyor (e.g., smaller
than the conveyor by at least about 1%, smaller than the conveyor
by at least about 5%, smaller than the conveyor by at least about
10%, smaller than the conveyor by at least about 15%, smaller than
the conveyor by at least about 20%, smaller than the conveyor by at
least about 25%). As the biomass is conveyed in the direction
indicated by the arrows, the biomass is spread out over the entire
width of the trough so that at about the dashed line defined by AB
and areas downstream of this line, the biomass covers the entire
width of the trough. Additionally to this spreading, the biomass
forms a layer of substantially uniform thickness on the conveyor as
the material moves down the conveyor. At some distance from line
AB, the electron beam impinges on and through the biomass layer.
The electron beam is raster scanned over an area 126, the radiation
area (zone, field, electron shower). A detailed view of the raster
scan area is shown as FIG. 1C. The path of the raster (e.g., a
locus of scanned electron beams) is shown projected on the surface
of irradiated material wherein the arrows show the path of the
raster scan. In other embodiments, the hopper opening is
approximately commensurate in size with the trough so that the area
124 spans the entire width of the trough.
[0037] FIG. 1D shows a right side cut out view of a system for
irradiating biomass. As shown, the biomass particles 178 form a
uniform layer 150 as they are conveyed through the electron beam
116 with minimal up and down motion of the particles. The electron
beam is extracted out of the high vacuum side of the scan horn 120
through the scan horn window 174 and then through a window 115
mounted to the cover of the conveyor 113. The tumbling and changing
orientation of biomass particles, the even spreading of the biomass
along the whole width of the trough as previously discussed, and
the raster scan of the e-beam ensures a substantially uniform
irradiation of the biomass as it moves down the conveyor through
the electron beam shower. The movement of the biomass can also help
in cooling (e.g., air cooling) of the biomass.
[0038] FIG. 1E shows a cross sectional detailed view of the scan
horn and window mounted in the cover. The scan horn includes horn
window cooler 170 and the conveyor includes enclosure window cooler
172 to blow air at high velocity across the windows as indicted by
the small arrows. The electrons in the electron beam 116 pass
through the high vacuum of the scan horn 120 through the scan horn
window 174, through the cooling air gap between the scan horn
window and enclosure window, through the enclosure window 115 and
impinge on and penetrate through the biomass material 178 on the
conveyor surface. The scan horn window is curved towards the vacuum
side of the scan horn, for example, due to the vacuum. The
enclosure window is shown curved towards the conveyed material. The
curvature of the windows can help the cooling air path flow past
the window for efficient cooling. The enclosure window is mounted
on the cover 179 of the enclosed conveyor.
[0039] Biomass can be manufactured into various products by the
methods described herein, for example, by reference to FIG. 2,
showing a process for manufacturing an alcohol can include, for
example, optionally mechanically treating a feedstock 210. Such
treatment can make the feedstock easier to convey, for example, on
with vibratory conveyor and/or pneumatic conveyor. Before and/or
after this treatment, the feedstock can be treated with another
physical treatment, for example, irradiation while conveying on a
vibratory conveyor as described herein, to reduce or further reduce
its recalcitrance 212, and saccharifying the feedstock, to form a
sugar solution 214. Optionally, the method may also include
transporting, e.g., by pipeline, railcar, truck or barge, the
solution (or the feedstock, enzyme and water, if saccharification
is performed en route) to a manufacturing plant 216. In some cases
the saccharified feedstock is further bioprocessed (e.g.,
fermented) to produce a desired product 218 and byproduct 211. The
resulting product may in some implementations be processed further,
e.g., by distillation 220. If desired, the steps of measuring
lignin content 222 and setting or adjusting process parameters
based on this measurement 224 can be performed at various stages of
the process, as described in U.S. patent application Ser. No.
12/704,519, filed on Feb. 11, 2010, the entire disclosure of which
is incorporated herein by reference.
[0040] Vibratory conveyors work by the principle of applying an
oscillating force or vibration to a material to be conveyed, and
particularly to the trough of a conveyor onto which the material to
be conveyed is placed. The oscillating force can be supplied by a
driver assembly that is mechanically coupled to the trough, as well
as elastic elements also mechanically coupled to the trough e.g.,
springs, leaf spring and/or coil spring. The vibrations can be, for
example, supplied by the driver assembly that can include one or
more of the drive motors coupled to one or more eccentric cranks or
eccentric fly wheels. In some embodiments the vibratory conveyors
are natural frequency vibrating conveyors based on obtaining a
common frequency between the elastic elements and the drive
assembly, for example, as disclosed in U.S. Pat. No. 4,813,532
filed Jan. 15, 1988 and published Mar. 21, 1989, the entire
disclosure of which is incorporated herein by reference.
[0041] The driver assembly, elastic elements and coupling to the
trough can provide motion to the surface of the trough, on which
the feedstock to be conveyed is placed. The motions include all
combined directions and magnitudes of x, y and z vectors, where x
is the direction of conveying biomass, y is the direction
transverse to conveying and z is the direction perpendicular to and
orthogonal to the x and y vectors. The displacement distance of the
trough can be varied for optimal performance. For example,
displacement in the x direction is between about 1/16 inch and 12
inch (e.g., between about 1/16 inch and 8 inch, between about 1/16
inch and 4 inch, between about 1/16 inch and 1 inch, between about
1/8 inch and 12 inch, between about 1/8 inch and 6 inch, between
about 1/8 inch and 2 inch, between about 1/8 inch and 1 inch,
between about 1/4 inch and 6 inch, between about 1/4 inch and 4
inch, between about 1/4 inch and 2 inch, between about 1/4 inch and
1 inch, between about 1/2 inch and 6 inch, between about 1/2 inch
and 4 inch, between about 1/2 inch and 2 inch, between about 1/2
inch and 1 inch, between about 1 inch and 6 inch, between about 1
inch and 4 inch). Displacement in the z direction can be, for
example, be between about 0 and 3 inch (e.g., between about 0.004
inch and 3 inch, between about 0.008 inch and 3 inch, between about
0.016 inch and 3 inch, between about 0.025 inch and 3 inch, between
about 0.05 inch and 3 inch, between about 0.1 inch and 3 inch,
between about 1/4 inch and 3 inch, between about 1/2 inch and 3
inch, between about 1 inch and 3 inch, between about 0.008 Inch and
1 inch, between about 0.016 inch and 1 inch, between about 0.025
inch and 1 inch, between about 0.05 inch and 1 inch, between about
0.1 inch and 1 inch, between about 1/4 inch and 1 inch, between
about 1/2 inch and 1 inch, between about 1/16 inch and 3/4 inch,
between about 1/8 inch and 3/4 inch, between about 1/4 inch and 3/4
inch, between about 1/2 inch and 3/4 inch). For example, the
displacement in the x direction can be greater than the
displacement in the z direction by a ratio less than about 3000:1
(e.g., less than about 1000 to 1, less than about 500 to 1, less
than about 100 to 1, less than about 50 to 1, less than about 10 to
1, less than about 5:1, less than about 2:1). The displacement in
they direction can be less than 1 inch (e.g., less than about 0.5
inch, less than about 0.1 inch, less than about 0.05 inch, less
than about 0.005 inch, or even about 0). The frequency of the
oscillations can be between 1 and 60 kHz. For example, the
frequency can be between about 1 and 100 Hz (e.g., between about 10
and 100 Hz, between about 20 and 100 Hz, between about 40 and 100
Hz, between about 60 and 100 Hz, between about 10 and 80 Hz,
between about 20 and 80 Hz, between about 40 and 80 Hz, between
about 60 and 80 Hz, between about 20 and 60 Hz). The frequency of
oscillation can be higher. For example, the frequency of
oscillation can be between about 100 Hz and 20 kHz (e.g., between
about 100 Hz and 15 kHz, between about 100 Hz and 10 kHz, between
about 100 Hz and 5 kHz, between about 500 Hz and 20 kHz, between
about 500 Hz and 15 kHz, between about 500 Hz and 10 kHz, between
about 500 Hz and 5 kHz, between about 1 and 20 kHz, between about 1
and 15 kHz, between about 1 and 10 kHz, between about 1 and 5 kHz).
The frequency can be even much higher, for example, in the
ultrasonic range (e.g., between about 20 and 60 kHz, between about
30 and 60 kHz, between about 40 and 60 kHz, between about 50 and 60
kHz, between about 20 and 50 kHz, between about 30 and 50 kHz,
between about 40 and 50 kHz, between about 20 and 40 kHz, between
about 30 and 40 kHz, between about 20 and 30 kHz).
[0042] There are at least three types of vibratory conveyors e.g.,
that can be utilized in the methods herein described. Combinations
of these and alternatives can be designed. The three types of
conveyors are discussed below.
[0043] In one type of vibratory conveyor, as depicted in FIG. 3A, a
vertical force is applied to the trough 310 and the trough is
inclined at an angle .alpha. (alpha) to the horizontal, for
example, at least 1.degree. (arc degree) e.g., at least 5.degree.,
at least 10.degree., at least 20.degree.). In another configuration
the trough is formed into a downwards series of steps (not shown)
with a downward incline of at least 1.degree. (e.g., at least
5.degree., at least 10.degree., at least 20.degree., at least
30.degree., at least 40.degree., at least 50.degree., at least
60.degree.). A material, for example, shown as a particle 312 moves
sequentially to positions, shown as open circles, the direction of
movement shown by arrows. This movement occurs because an
oscillatory force or vibrational force is applied perpendicular to
the trough surface as shown by the two headed arrows. The
oscillatory force repeatedly lofts the material to be conveyed
perpendicular to the trough while gravity acts on the material to
move it down the incline, or alternatively the steps, of the
trough.
[0044] In a second type of vibratory conveyor, depicted in FIG. 3B,
the materials to be conveyed are placed on a trough 320 and a
purely horizontal force, indicated by the two headed arrow, causes
a horizontal movement of the materials. The force is an oscillating
force such that the maximum horizontal vibratory forces applied to
the trough in the direction of conveyance is less than the static
friction force acting between the trough and the material, while
the forces applied to the material in the direction opposite to
conveyance is higher than the static friction. In this way
adherence is maintained between the material and the trough in the
direction of conveyance but not in the direction opposite
conveyance and the material is conveyed forward in a shuffling
manner. A material, for example, shown as particle 322 moves
sequentially to positions, shown as open circles, the shuffling
movement indicated by the single headed arrows. As well as
horizontal and downwards conveying, these types of conveyors can
convey materials in upwards direction of up to about 25
degrees.
[0045] In a third type of vibratory conveyor, depicted by FIG. 3C,
the material carrying trough 330 is vibrated, as shown by the two
headed arrows, at an angle .beta. (beta) to the horizontal, for
example, 45 degrees. The material is lofted upwards and in the
horizontal direction of incline. Therefore, the material is
conveyed forward in a bouncing manner as depicted by the particle
332 the movement indicated by the single headed arrows. As well as
horizontal and downwards, these vibratory conveyors can convey
materials upwards as well as downwards, for example, at an upwards
direction of up to about 25 degrees.
[0046] FIG. 4 is a perspective view of a vibratory conveyor of the
third type described above. The trough 410 has side walls 412 and
414 and is supported by support arms, legs or structures 416 that
are pivotally connected to the trough on one end and pivotally
connected to a base support 418 on the other end. Coil springs are
420 shown at a 45.degree. to the trough and support oscillations at
this angle of the trough. A drive assembly 422 coupled to the
trough provides the force for the oscillatory motion. Many other
configurations of vibratory conveyors are known. For example,
instead of coil springs, leaf springs can be used.
[0047] FIG. 5 shows a perspective view of another example of a
vibratory conveyor of the third type. This example of a vibratory
conveyor includes a drive assembly 510, leaf springs 520, a trough
530, cover 540 and access ports 550. Covers for the conveyors can
be added to mitigate, for example, dust generation.
[0048] FIG. 6A shows a perspective view of a vibratory conveyor of
the second type 610. The trough 612 carries biomass that has been
delivered to the conveyor 630. At the upstream end of the conveyor
where the biomass is delivered, e.g., near 630, the biomass may
form a pile with a peak. Downstream, e.g., near 640 the biomass is
more uniformly spread. The trough is supported by support
structures 616 which have pairs of longitudinally spaced vertical
legs 617, each pair of legs are connected by horizontal cross
members 618 and longitudinal base members 619. The trough 612 is
suspended from the overhead structures 616 by vertical straps 621.
The straps 621 are attached at one end to the horizontal cross
members 618 and at the other end to trough support members 622. The
straps 621 are constructed of a dimension in the direction
transverse to the path of conveyance much larger than that of the
direction parallel to the path of conveyance, and therefore the
vertical straps 621 can act as resilient leaf-springs permitting
displacement of the trough only in the direction of conveyance. The
horizontal deflection of the bottoms of the straps 621 combine with
the forces imparted by a vibration generating apparatus 623
creating motion of the trough 612 in substantially horizontal
direction with very little vertical deflection. The vibration
generating apparatus 623 can, for example, include an eccentric fly
wheels 683, 684, 685 and 686 as shown in front side view FIG. 6B.
U.S. Pat. No. 5,131,525 (pub. Jul. 21, 1992) describes vibratory
conveyors, the entire disclosure thereof incorporated herein by
reference.
[0049] The vibratory conveyors described can include screens used
for sieving and sorting materials. Port openings on the side or
bottom of the troughs can be used for sorting, selecting or
removing specific materials, for example, by size or shape. Some
conveyors have counterbalances to reduce the dynamic forces on the
support structure. Some vibratory conveyors are configured as
spiral elevators, are designed to curve around surfaces and/or are
designed to drop material from one conveyor to another (e.g., in a
step, cascade or as a series of steps or a stair). Along with
conveying materials conveyors can be used, by themselves or coupled
with other equipment or systems, for screening, separating,
sorting, classifying, distributing, sizing, inspection, picking,
metal removing, freezing, blending, mixing, orienting, heating,
cooking, drying, dewatering, cleaning, washing, leaching,
quenching, coating, de-dusting and/or feeding. The conveyors can
also include covers (e.g., dust-tight covers), side discharge
gates, bottom discharge gates, special liners (e.g., anti-stick,
stainless steel, rubber, custom steal, and or grooved), divided
troughs, quench pools, screens, perforated plates, detectors (e.g.,
metal detectors), high temperature designs, food grade designs,
heaters, dryers and or coolers. In addition, the trough can be of
various shapes, for example, flat bottomed, vee shaped bottom,
flanged at the top, curved bottom, flat with ridges in any
direction, tubular, half pipe, covered or any combinations of
these. In particular, the conveyors can be coupled with an
irradiation systems and/or equipment.
[0050] The conveyors (e.g., vibratory conveyor) can be made of
corrosion resistant materials. The conveyors can utilize structural
materials that include stainless steel (e.g., 304, 316 stainless
steel, HASTELLOY.RTM. ALLOYS and INCONEL.RTM. Alloys). For example,
HASTELLOY.RTM. Corrosion-Resistant alloys from Hynes (Kokomo, Ind.,
USA) such as HASTELLOY.RTM. B-3.RTM. ALLOY, HASTELLOY.RTM.
HYBRID-BC1.RTM. ALLOY, HASTELLOY.RTM. C-4 ALLOY, HASTELLOY.RTM.
C-22.RTM. ALLOY, HASTELLOY.RTM. C-22HS.RTM. ALLOY, HASTELLOY.RTM.
C-276 ALLOY, HASTELLOY.RTM. C-2000.RTM. ALLOY, HASTELLOY.RTM.
G-30.RTM. ALLOY, HASTELLOY.RTM. G-35.RTM. ALLOY, HASTELLOY.RTM. N
ALLOY and HASTELLOY.RTM. ULTIMET.RTM. alloy.
[0051] The vibratory conveyors can include non-stick release
coatings, for example, TUFFLON.TM. (DuPont, Delaware, USA). The
vibratory conveyors can also include corrosion resistant coatings.
For example, coatings that can be supplied from Metal Coatings Corp
(Houston, Tex., USA) and others such as Fluoropolymer, XYLAN.RTM.,
Molybdenum Disulfide, Epoxy Phenolic, Phosphate-ferrous metal
coating, Polyurethane-high gloss topcoat for epoxy, inorganic zinc,
Poly Tetrafluoro ethylene, PPS/RYTON.RTM., fluorinated ethylene
propylene, PVDF/DYKOR.RTM., ECTFE/HALAR.RTM. and Ceramic Epoxy
Coating. The coatings can improve resistance to process gases
(e.g., ozone), chemical corrosion, pitting corrosion, galling
corrosion and oxidation.
[0052] In one embodiment, the conveyors include a cover. These
enclosed conveyors are useful, for example, for the mitigation of
dust generation. In some embodiments of these enclosed conveyors, a
window that is transparent to the electron beam is mounted onto the
cover, for example, forming an integral part of the cover. The
window can be aligned with the electron beam so that the electrons
can pass through the window and irradiate material being conveyed
through the radiation field underneath the widow (e.g. underneath
the electron beam). The windows are typically foils at least 10 um
(micro meters) thick (e.g., at least 15 um, at least 20 um, at
least 25 um, at least 30 um, at least 40 um). The electron beam
generator also includes at least one window for extraction of
electrons from the vacuum side of the generator to the atmospheric
side. The distance between the facing surfaces of the window foil
mounted to the electron beam generator (e.g., mounted to the
scanning horn) and window foil mounted to the enclosure of the
vibratory conveyor, when the system is being used to irradiate a
feedstock, is at least about 0.1 cm (e.g. at least about 1 cm, at
least about 2 cm, at least about 4 cm, at least about 5 cm, at
least about 6 cm, at least about 7 cm, at least about 8 cm, at
least about 9 cm, or at least about 10 cm, at least about 12 cm, at
least about 15 cm). Preferably the window foils are cooled with a
cooling fluid, for example, by using an air blower to blow air over
the surface of the window foils.
[0053] It is generally preferred that the material be in a bed or
layer of substantially uniform thickness or depth while being
irradiated. For example, a desired thickness can be, between about
0.0312 and 5 inches (e.g., between about 0.0625 and 2.000 inches,
between about 0.125 and 1 inches, between about 0.125 and 0.5
inches, between about 0.3 and 0.9 inches, between about 0.2 and 0.5
inches between about 0.25 and 1.0 inches, between about 0.25 and
0.5 inches, 0.100+/-0.025 inches, 0.150+/-0.025 inches,
0.200+/-0.025 inches, 0.250+/-0.025 inches, 0.300+/-0.025 inches,
0.350+/-0.025 inches, 0.400+/-0.025 inches, 0.450+/-0.025 inches,
0.500+/-0.025 inches, 0.550+/-0.025 inches, 0.600+/-0.025 inches,
0.700+/-0.025 inches, 0.750+/-0.025 inches, 0.800+/-0.025 inches,
0.850+/-0.025 inches, 0.900+/-0.025 inches or 0.900+/-0.025
inches.
[0054] Vibratory conveyors are particularly useful for spreading
the material and producing a uniform layer on the conveyor trough
surface. For example, the initial feedstock can form a pile of
material that can be at least four feet high (e.g., at least about
3 feet, at least about 2 feet, at least about 1 foot, at least
about 6 inches, at least about 5 inches, at least about, 4 inches,
at least about 3 inches, at least about 2 inches, at least about 1
inch, at least about 1/2 inch) and spans less than the width of the
conveyor (e.g., less than about 10%, less than about 20%, less than
about 30%, less than about 40%, less than about 50%, less than
about 60%, less than about 70%, less than about 80%, less than
about 90%, less than about 95%, less than about 99%). The vibratory
conveyor can spread the material to span the entire width of the
conveyor trough and have a uniform thickness, preferably as
discussed above. In some cases, an additional spreading method can
be useful. For example, a spreader such as a broadcast spreader, a
drop spreader (e.g., a CHRISTY SPREADER.TM.) or combinations
thereof can be used to drop (e.g., place, pour, spill and/or
sprinkle) the feedstock over a wide area. Optionally, the spreader
can deliver the biomass as a wide shower or curtain onto the
vibratory conveyor. Additionally, a second conveyor, upstream from
the first conveyor (e.g., the first conveyor is used in the
irradiation of the feedstock), can drop biomass onto the first
conveyor, where the second conveyor can have a width transverse to
the direction of conveying smaller than the first conveyor. In
particular, when the second conveyor is a vibratory conveyor, the
feedstock is spread by the action of the second and first conveyor.
In some optional embodiments, the second conveyor ends in a bias
cross cut discharge (e.g., a bias cut with a ratio of 4:1) so that
the material can be dropped as a wide curtain (e.g., wider than the
width of the second conveyor) onto the first conveyor. The initial
drop area of the biomass by the spreader (e.g., broadcast spreader,
drop spreader, conveyor, or cross cut vibratory conveyor) can span
the entire width of the first vibratory conveyor, or it can span
part of this width. Once dropped onto the conveyor, the material is
spread even more uniformly by the vibrations of the conveyor so
that, preferably, the entire width of the conveyor is covered with
a uniform layer of biomass. In some embodiments combinations of
spreaders can be used. Some methods of spreading a feed stock are
described in U.S. Pat. No. 7,153,533, filed Jul. 23, 2002 and
published Dec. 26, 2006, the entire disclosure of which is
incorporated herein by reference.
[0055] Generally, it is preferred to convey the material as quickly
as possible through the electron beam to maximize throughput. For
example, the material can be conveyed at rates of at least 1
ft/min, e.g., at least 2 ft/min, at least 3 ft/min, at least 4
ft/min, at least 5 ft/min, at least 10 ft/min, at least 15 ft/min,
at least 20 ft/min, at least 25 ft/min, at least 30 ft/min, at
least 40 ft/min, at least 50 ft/min, at least 60 ft/min, at least
70 ft/min, at least 80 ft/min, at least 90 ft/min. The rate of
conveying is related to the beam current and targeted irradiation
dose, for example, for a 1/4 inch thick biomass spread over a 5.5
foot wide conveyor and 100 mA, the conveyor can move at about 20
ft/min to provide a useful irradiation dosage (e.g. about 10 Mrad
for a single pass), at 50 mA the conveyor can move at about 10
ft/min to provide approximately the same irradiation dosage.
[0056] The rate at which material can be conveyed depends on the
shape and mass of the material being conveyed. Flowing materials
e.g., particulate materials, are particularly amenable to conveying
with vibratory conveyors. Conveying speeds can, for example, be, at
least 100 lb/hr (e.g., at least 500 lb/hr, at least 1000 lb/hr, at
least 2000 lb/hr, at least 3000 lb/hr, at least 4000 lb/hr, at
least 5000 lb/hr, at least 10,000 lb/hr, at least 15,000 lb/hr, or
even at least 25,000 lb/hr). Some typical conveying speeds can be
between about 1000 and 10,000 lb/hr, (e.g., between about 1000
lb/hr and 8000 lb/hr, between about 2000 and 7000 lb/hr, between
about 2000 and 6000 lb/hr, between about 2000 and 50001b/hr,
between about 2000 and 4500 lb/hr, between about 1500 and 5000
lb/hr, between about 3000 and 7000 lb/hr, between about 3000 and
6000 lb/hr, between about 4000 and 6000 lb/hr and between about
4000 and 5000 lb/hr). Typical conveying speeds depend on the
density of the material. For example, for a biomass with a density
of about 35 lb/ft.sup.3, and a conveying speed of about 5000 lb/hr,
the material is conveyed at a rate of about 143 ft.sup.3/hr, if the
material is 1/4'' thick and is in a trough 5.5 ft wide, the
material is conveyed at a rate of about 1250 ft/hr (about 21
ft/min). Rates of conveying the material can therefore vary
greatly. Preferably, for example, a 1/4'' thick layer of biomass,
is conveyed at speeds of between about 5 and 100 ft/min (e.g.
between about 5 and 100 ft/min, between about 6 and 100 ft/min,
between about 7 and 100 ft/min, between about 8 and 100 ft/min,
between about 9 and 100 ft/min, between about 10 and 100 ft/min,
between about 11 and 100 ft/min, between about 12 and 100 ft/min,
between about 13 and 100 ft/min, between about 14 and 100 ft/min,
between about 15 and 100 ft/min, between about 20 and 100 ft/min,
between about 30 and 100 ft/min, between about 40 and 100 ft/min,
between about 2 and 60 ft/min, between about 3 and 60 ft/min,
between about 5 and 60 ft/min, between about 6 and 60 ft/min,
between about 7 and 60 ft/min, between about 8 and 60 ft/min,
between about 9 and 60 ft/min, between about 10 and 60 ft/min,
between about 15 and 60 ft/min, between about 20 and 60 ft/min,
between about 30 and 60 ft/min, between about 40 and 60 ft/min,
between about 2 and 50 ft/min, between about 3 and 50 ft/min,
between about 5 and 50 ft/min, between about 6 and 50 ft/min,
between about 7 and 50 ft/min, between about 8 and 50 ft/min,
between about 9 and 50 ft/min, between about 10 and 50 ft/min,
between about 15 and 50 ft/min, between about 20 and 50 ft/min,
between about 30 and 50 ft/min, between about 40 and 50 ft/min). It
is preferable that the material be conveyed at a constant rate, for
example, to help maintain a constant irradiation of the material as
it passes under the electron beam (e.g., shower, field).
[0057] FIG. 7 shows an irradiation process. This process can be
part of the process described in FIG. 2 although it can
alternatively be part of a different process. Initially, biomass
can be delivered to a vibratory conveyor 750. The biomass can be
treated by a pre-irradiation process 752 prior to it being conveyed
through an irradiation zone 754. After irradiation, the biomass can
be post processed 756. The process can be repeated (e.g., dashed
arrow A).
[0058] Biomass can be delivered to the vibratory conveyor 750 by
using another vibratory conveyor, a belt conveyor, a pneumatic
conveyor, a screw conveyor, a hopper, a dispersing machine (e.g., a
spreader), a pipe, manually or by combination of these. The biomass
can, for example, be dropped, poured, sprinkled and/or placed onto
the vibratory conveyor by any of these methods. The biomass can be
in a dry form, for example, with less than about 35% moisture
content (e.g., less than about 20%, less than about 15%, less than
about 10% or less about than 5%, less than about 4%, less than
about 3%, less than about 2%, and even less than about 1%). The
biomass can also be delivered in a wet state, for example, as a wet
solid, a slurry or a suspension with at least 10 wt % solids (e.g.
at least 20 wt. %, at least 30 wt. %, at least 40 wt. %, at least
50 wt. %, at least 60 wt. %, at least 70 wt. %).
[0059] In some cases, the pre-irradiation processing 752 includes
screening of the biomass material. Screening can be by a vibratory
screener coupled to the vibratory conveyor. For example, a
vibratory screener that has a mesh or perforated plate onto which
the biomass falls with a desired opening size, for example, less
than 6.35 mm (1/4 inch, 0.25 inch), {e.g., less 3.18 mm (1/8 inch,
0.125 inch), less than 1.59 mm ( 1/16 inch, 0.0625 inch), is less
than 0.79 mm ( 1/32 inch, 0.03125 inch), e.g., less than 0.51 mm (
1/50 inch, 0.02000 inch), less than 0.40 mm ( 1/64 inch, 0.015625
inch), less than 0.23 mm (0.009 inch), less than 0.20 mm ( 1/128
inch, 0.0078125 inch), less than 0.18 mm (0.007 inch), less than
0.13 mm (0.005 inch), or even less than less than 0.10 mm ( 1/256
inch, 0.00390625 inch)}. In one configuration the desired biomass
falls through the perforations or screen and thus biomass larger
than the perforations or screen are not irradiated. These larger
materials can be re-processed, for example, by comminuting, or they
can simply be removed from processing. In another configuration
material that is larger than the perforations is irradiated and the
smaller material is removed by the screening process or recycled by
some other means. In this kind of a configuration, the conveyor
itself (for example, a part of the conveyor) can be perforated or
made with a mesh. For example, in a one particular embodiment the
biomass material may be wet and the perforations or mesh allow
water to drain away from the biomass before irradiation.
[0060] Screening of material can also be by a manual method, for
example, by an operator or mechanoid (e.g., a robot equipped with a
color, reflectivity or other sensor) that removes unwanted
material. Screening can also be by magnetic screening wherein a
magnet is disposed near the conveyed material and the magnetic
material is removed magnetically.
[0061] Optional pre-irradiation processing 752 can include heating
the material. For example, a portion of the conveyor can be sent
through a heated zone. The heated zone can be created, for example,
by IR radiation, Microwaves, combustion (e.g., gas, coal, oil,
biomass), resistive heating and/or inductive coils. The heat can be
applied from one side or more than one side, can be continuous or
periodic and/or can be for only a portion of the material or all
the material. For example, a portion of the trough can be heated by
use of a heating jacket. Heating can be, for example, for the
purpose of drying the material. In the case of drying the material,
this can also be facilitated, with or without heating, by the
movement of a gas (e.g., air, nitrogen, oxygen, CO.sub.2, Argon,
He) over and/or through the biomass as it is being conveyed. Drying
can also be in vacuo.
[0062] Pre-irradiation processing 752 can also be with reactive
gases, for example, ozone, ammonia, steam or a plasma. The gas can
be supplied above atmospheric pressure.
[0063] Optionally, pre-irradiation processing 752 can include
cooling the material. Cooling material is described in U.S. Pat.
No. 7,900,857 filed Jul. 14, 2009 and published Mar. 8, 2011, the
entire disclosure of which in incorporated herein by reference.
[0064] Another optional pre-irradiation processing 750 can include
adding a material to the biomass. Vibratory conveying is very well
suited to be coupled with the addition of a material, for example,
by showering, sprinkling and or pouring a material onto the biomass
as it is conveyed, because the vibratory conveyor provides
agitation, tumbling and/or turning of the biomass that allows for
efficient mixing and/or homogenization of the biomass with any
added material. Materials that can be added include, for example,
metals, ceramics and/or ions as described in U.S. application Ser.
No. 12/605,534 and U.S. application Ser. No. 12/639,289 the
complete disclosures of which are incorporated herein by reference.
Other materials that can be added include acids, bases, oxidants
(e.g., peroxides, chlorates), polymers, polymerizable monomers
(e.g., containing unsaturated bonds), water, catalysts, enzymes
and/or organisms. Materials can be added, for example, in pure
form, as a solution in a solvent (e.g., water or an organic
solvent) and/or as a solution. In some cases the solvent is
volatile and can be made to evaporate e.g., by heating and/or
blowing gas as previously described. The added material may form a
uniform coating on the biomass or be a homogeneous mixture of
different components (e.g., biomass and additional material). The
added material can modulate the subsequent irradiation step by
increasing the efficiency of the irradiation, damping the
irradiation or changing the effect of the irradiation (e.g., from
electron beams to X-rays or heat). The method may have no impact on
the irradiation but may be useful for further downstream
processing. The added material may help in conveying the material,
for example, by lowering dust levels.
[0065] After optional pre-radiation treatment the material is
conveyed by the vibratory conveyor through an irradiation zone
(e.g., the radiation field) 754. Radiation can be by, for example,
electron beam, ion beam, 100 nm to 28 nm ultraviolet (UV) light,
gamma or X-ray radiation. For example, radiation treatments and
equipment are discussed below. Radiation treatments and systems for
treatments are also discussed in U.S. Pat. No. 8,142,620, and U.S.
patent application Ser. No. 12/417,731, the entire disclosures of
which are incorporated herein by reference.
[0066] Referring again to FIG. 7, after the biomass material has
been conveyed through the radiation zone optional post processing
756 can be done. The optional post processing can, for example, be
a process described with respect to the pre-irradiation processing.
For example, the biomass can be screened, heated, cooled, and/or
combined with additives. Uniquely to post-irradiation, quenching of
the radicals can occur, for example, quenching of radicals by the
addition of fluids (e.g., oxygen, reactive liquids), using
pressure, using heating and or addition of radical scavengers.
Quenching of biomass that has been irradiated is described in U.S.
Pat. No. 8,083,906 and issued Dec. 27, 2011 the disclosure of which
is incorporate herein by reference.
[0067] It may be advantageous to repeat irradiation to more
thoroughly reduce the recalcitrance of the biomass. For example, as
shown by path A in FIG. 7. In particular the process parameters
might be adjusted after a first (e.g., second, third, fourth or
more) pass depending on the recalcitrance of the material. In some
embodiments, the conveyor is a closed circular system where the
biomass is conveyed multiple times through the various processes
described above. In some other embodiments multiple irradiation
devices (e.g., electron beam generators) are used to irradiate the
biomass multiple (e.g., 2, 3, 4 or more) times. In yet other
embodiments, a single electron beam generator may be the source of
multiple beams (e.g., 2, 3, 4 or more beams) that can be used for
irradiation of the biomass.
[0068] Some more details and reiterations of processes for treating
a feedstock that can be utilized, for example, with the embodiments
already discussed above, or in other embodiments, are described in
the following disclosures.
Systems for Treating a Feedstock
[0069] Processes for conversion of a feedstock to sugars and other
products, in which the conveying methods discuss above may be used,
include, for example, optionally physically pre-treating the
feedstock, e.g., to reduce its size, before and/or after this
treatment, optionally treating the feedstock to reduce its
recalcitrance (e.g., by irradiation), and saccharifying the
feedstock to form a sugar solution. Saccharification can be
performed by mixing a dispersion of the feedstock in a liquid
medium, e.g., water with an enzyme, as will be discussed in detail
herein. Prior to treatment with an enzyme, pretreated biomass can
be subjected to hot water and pressure, e.g., 100-150 deg C.,
100-140, or 110-130 deg C. and associated pressure. Prior to
treatment with the enzyme the material is cooled to about 50 deg C.
(e.g. between about 40 and 60 deg C.). In addition or alternatively
prior to the treatment with an enzyme the pretreated biomass can be
treated with an acid, such as hydrochloric, sulfuric or phosphoric
acid, e.g., less than 10% concentration (e.g., less than 5%, e.g.
between about 0.01 and about 5%, between about 0.05 and about 1%,
between about 0.05 and about 0.5%). During or after
saccharification, the mixture (if saccharification is to be
partially or completely performed en route) or solution can be
transported, e.g., by pipeline, railcar, truck or barge, to a
manufacturing plant. At the plant, the solution can be
bioprocessed, e.g., fermented, to produce a desired product or
intermediate, which can then be processed further, e.g., by
distillation. The individual processing steps, materials used and
examples of products and intermediates that may be formed will be
described in detail below.
Radiation Treatment
[0070] The feedstock can be treated with radiation to modify its
structure to reduce its recalcitrance. Such treatment can, for
example, reduce the average molecular weight of the feedstock,
change the crystalline structure of the feedstock, and/or increase
the surface area and/or porosity of the feedstock. Radiation can be
by, for example, electron beam, ion beam, 100 nm to 28 nm
ultraviolet (UV) light, gamma or X-ray radiation. Radiation
treatments and systems for treatments are discussed in U.S. Pat.
No. 8,142,620, and U.S. patent application Ser. No. 12/417,731, the
entire disclosures of which are incorporated herein by
reference.
[0071] Each form of radiation ionizes the biomass via particular
interactions, as determined by the energy of the radiation. Heavy
charged particles primarily ionize matter via Coulomb scattering;
furthermore, these interactions produce energetic electrons that
may further ionize matter. Alpha particles are identical to the
nucleus of a helium atom and are produced by the alpha decay of
various radioactive nuclei, such as isotopes of bismuth, polonium,
astatine, radon, francium, radium, several actinides, such as
actinium, thorium, uranium, neptunium, curium, californium,
americium, and plutonium. Electrons interact via Coulomb scattering
and bremsstrahlung radiation produced by changes in the velocity of
electrons.
[0072] When particles are utilized, they can be neutral
(uncharged), positively charged or negatively charged. When
charged, the charged particles can bear a single positive or
negative charge, or multiple charges, e.g., one, two, three or even
four or more charges. In instances in which chain scission is
desired to change the molecular structure of the carbohydrate
containing material, positively charged particles may be desirable,
in part, due to their acidic nature. When particles are utilized,
the particles can have the mass of a resting electron, or greater,
e.g., 500, 1000, 1500, or 2000 or more times the mass of a resting
electron. For example, the particles can have a mass of from about
1 atomic unit to about 150 atomic units, e.g., from about 1 atomic
unit to about 50 atomic units, or from about 1 to about 25, e.g.,
1, 2, 3, 4, 5, 10, 12 or 15 atomic units. Gamma radiation has the
advantage of a significant penetration depth into a variety of
material in the sample.
[0073] In embodiments in which the irradiating is performed with
electromagnetic radiation, the electromagnetic radiation can have,
e.g., energy per photon (in electron volts) of greater than
10.sup.2 eV, e.g., greater than 10.sup.3, 10.sup.4, 10.sup.5,
10.sup.6, or even greater than 10.sup.7 eV. In some embodiments,
the electromagnetic radiation has energy per photon of between
10.sup.4 and 10.sup.7, e.g., between 10.sup.5 and 10.sup.6 eV. The
electromagnetic radiation can have a frequency of, e.g., greater
than 10.sup.16 Hz, greater than 10.sup.17 Hz, 10.sup.18, 10.sup.19,
10.sup.20, or even greater than 10.sup.21 Hz. In some embodiments,
the electromagnetic radiation has a frequency of between 10.sup.18
and 10.sup.22 Hz, e.g., between 10.sup.19 to 10.sup.21 Hz.
[0074] Electron bombardment may be performed using an electron beam
device that has a nominal energy of less than 10 MeV, e.g., less
than 7 MeV, less than 5 MeV, or less than 2 MeV, e.g., from about
0.5 to about 4 MeV, from about 0.6 to about 3 MeV, from about 0.5
to 1.5 MeV, from about 0.8 to 1.8 MeV, from about 0.7 to about 2.5
MeV, or from about 0.7 to 1 MeV. In some implementations the
nominal energy is about 500 to 800 keV.
[0075] The electron beam may have a relatively high total beam
power (the combined beam power of all accelerating heads, or, if
multiple accelerators are used, of all accelerators and all heads),
e.g., at least 25 kW, e.g., at least 30, 40, 50, 60, 65, 70, 80,
100, 125, or 150 kW. In some cases, the power is even as high as
500 kW, 750 kW, or even 1000 kW or more. In some cases the electron
beam has a beam power of 1200 kW or more, e.g., 1400, 1600, 1800,
or even 300 kW.
[0076] This high total beam power is usually achieved by utilizing
multiple accelerating heads. For example, the electron beam device
may include two, four, or more accelerating heads. The use of
multiple heads, each of which has a relatively low beam power,
prevents excessive temperature rise in the material, thereby
preventing burning of the material, and also increases the
uniformity of the dose through the thickness of the layer of
material.
It is generally preferred that the bed of biomass material has a
relatively uniform thickness. In some embodiments the thickness is
less than about 1 inch (e.g., less than about 0.75 inches, less
than about 0.5 inches, less than about 0.25 inches, less than about
0.1 inches, between about 0.1 and 1 inch, between about 0.2 and 0.3
inches).
[0077] It is desirable to treat the material as quickly as
possible. In general, it is preferred that treatment be performed
at a dose rate of greater than about 0.25 Mrad per second, e.g.,
greater than about 0.5, 0.75, 1, 1.5, 2, 5, 7, 10, 12, 15, or even
greater than about 20 Mrad per second, e.g., about 0.25 to 2 Mrad
per second. Higher dose rates allow a higher throughput for a
target (e.g., the desired) dose. Higher dose rates generally
require higher line speeds, to avoid thermal decomposition of the
material. In one implementation, the accelerator is set for 3 MeV,
50 mA beam current, and the line speed is 24 feet/minute, for a
sample thickness of about 20 mm (e.g., comminuted corn cob material
with a bulk density of 0.5 g/cm.sup.3).
[0078] In some embodiments, electron bombardment is performed until
the material receives a total dose of at least 0.1 Mrad, 0.25 Mrad,
1 Mrad, 5 Mrad, e.g., at least 10, 20, 30 or at least 40 Mrad. In
some embodiments, the treatment is performed until the material
receives a dose of from about 10 Mrad to about 50 Mrad, e.g., from
about 10 to about 40 Mrad, from about 20 Mrad to about 40 Mrad, or
from about 25 Mrad to about 30 Mrad. In some implementations, a
total dose of 25 to 35 Mrad is preferred, applied ideally over a
couple of passes, e.g., at 5 Mrad/pass with each pass being applied
for about one second. Cooling methods such as cooling screw
conveyors and cooled conveying troughs can also be utilized, for
example, after each irradiation, after the total irradiation,
during irradiation and/or before irradiation.
[0079] Using multiple heads as discussed above, the material can be
treated in multiple passes, for example, two passes at 10 to 20
Mrad/pass, e.g., 12 to 18 Mrad/pass, separated by a few seconds of
cool-down, or three passes of 7 to 12 Mrad/pass, e.g., 5 to 20
Mrad/pass, 10 to 40 Mrad/pass, 9 to 11 Mrad/pass. As discussed
herein, treating the material with several relatively low doses,
rather than one high dose, tends to prevent overheating of the
material and also increases dose uniformity through the thickness
of the material. In some implementations, the material is stirred
or otherwise mixed during or after each pass and then smoothed into
a uniform layer again before the next pass, to further enhance
treatment uniformity.
[0080] In some embodiments, electrons are accelerated to, for
example, a speed of greater than 75 percent of the speed of light,
e.g., greater than 85, 90, 95, or 99 percent of the speed of
light.
[0081] In some embodiments, any processing described herein occurs
on lignocellulosic material that remains dry as acquired or that
has been dried, e.g., using heat and/or reduced pressure. For
example, in some embodiments, the cellulosic and/or lignocellulosic
material has less than about 25 wt. % retained water, measured at
25.degree. C. and at fifty percent relative humidity (e.g., less
than about 20 wt. %, less than about 15 wt. %, less than about 14
wt. %, less than about 13 wt. %, less than about 12 wt. %, less
than about 10 wt. %, less than about 9 wt. %, less than about 8 wt.
%, less than about 7 wt. %, less than about 6 wt. %, less than
about 5 wt. %, less than about 4 wt. %, less than about 3 wt. %,
less than about 2 wt. %, less than about 1 wt. %, or less than
about 0.5 wt. %.
[0082] In some embodiments, two or more ionizing sources can be
used, such as two or more electron sources. For example, samples
can be treated, in any order, with a beam of electrons, followed by
gamma radiation and UV light having wavelengths from about 100 nm
to about 280 nm. In some embodiments, samples are treated with
three ionizing radiation sources, such as a beam of electrons,
gamma radiation, and energetic UV light. The biomass is conveyed
through the treatment zone where it can be bombarded with
electrons.
[0083] It may be advantageous to repeat the treatment to more
thoroughly reduce the recalcitrance of the biomass and/or further
modify the biomass. In particular the process parameters can be
adjusted after a first (e.g., second, third, fourth or more) pass
depending on the recalcitrance of the material. In some
embodiments, a conveyor can be used which includes a circular
system where the biomass is conveyed multiple times through the
various processes described above. In some other embodiments
multiple treatment devices (e.g., electron beam generators) are
used to treat the biomass multiple (e.g., 2, 3, 4 or more) times.
In yet other embodiments, a single electron beam generator may be
the source of multiple beams (e.g., 2, 3, 4 or more beams) that can
be used for treatment of the biomass.
[0084] The effectiveness in changing the molecular/supermolecular
structure and/or reducing the recalcitrance of the
carbohydrate-containing biomass depends on the electron energy used
and the dose applied, while exposure time depends on the power and
dose. In some embodiments, the dose rate and total dose are
adjusted so as not to destroy (e.g., char or burn) the biomass
material. For example, the carbohydrates should not be damaged in
the processing so that they can be released from the biomass
intact, e.g. as monomeric sugars.
In some embodiments, the treatment (with any electron source or a
combination of sources) is performed until the material receives a
dose of at least about 0.05 Mrad, e.g., at least about 0.1, 0.25,
0.5, 0.75, 1.0, 2.5, 5.0, 7.5, 10.0, 15, 20, 25, 30, 40, 50, 60,
70, 80, 90, 100, 125, 150, 175, or 200 Mrad. In some embodiments,
the treatment is performed until the material receives a dose of
between 0.1-100 Mrad, 1-200, 5-200, 10-200, 5-150, 50-150 Mrad,
5-100, 5-50, 5-40, 10-50, 10-75, 15-50, 20-35 Mrad.
[0085] In some embodiments, relatively low doses of radiation are
utilized, e.g., to increase the molecular weight of a cellulosic or
lignocellulosic material (with any radiation source or a
combination of sources described herein). For example, a dose of at
least about 0.05 Mrad, e.g., at least about 0.1 Mrad or at least
about 0.25, 0.5, 0.75. 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, or at
least about 5.0 Mrad. In some embodiments, the irradiation is
performed until the material receives a dose of between 0.1 Mrad
and 2.0 Mrad, e.g., between 0.5 rad and 4.0 Mrad or between 1.0
Mrad and 3.0 Mrad.
[0086] It also can be desirable to irradiate from multiple
directions, simultaneously or sequentially, in order to achieve a
desired degree of penetration of radiation into the material. For
example, depending on the density and moisture content of the
material, such as wood, and the type of radiation source used
(e.g., gamma or electron beam), the maximum penetration of
radiation into the material may be only about 0.75 inch. In such a
case, a thicker section (up to 1.5 inch) can be irradiated by first
irradiating the material from one side, and then turning the
material over and irradiating from the other side. Irradiation from
multiple directions can be particularly useful with electron beam
radiation, which irradiates faster than gamma radiation but
typically does not achieve as great a penetration depth.
Radiation Opaque Materials
[0087] As previously discussed, the invention can include
processing the material in a vault and/or bunker that is
constructed using radiation opaque materials. In some
implementations, the radiation opaque materials are selected to be
capable of shielding the components from X-rays with high energy
(short wavelength), which can penetrate many materials. One
important factor in designing a radiation shielding enclosure is
the attenuation length of the materials used, which will determine
the required thickness for a particular material, blend of
materials, or layered structure. The attenuation length is the
penetration distance at which the radiation is reduced to
approximately 1/e (e=Eulers number) times that of the incident
radiation. Although virtually all materials are radiation opaque if
thick enough, materials containing a high compositional percentage
(e.g., density) of elements that have a high Z value (atomic
number) have a shorter radiation attenuation length and thus if
such materials are used a thinner, lighter shielding can be
provided. Examples of high Z value materials that are used in
radiation shielding are tantalum and lead. Another important
parameter in radiation shielding is the halving distance, which is
the thickness of a particular material that will reduce gamma ray
intensity by 50%. As an example for X-ray radiation with an energy
of 0.1 MeV the halving thickness is about 15.1 mm for concrete and
about 2.7 mm for lead, while with an X-ray energy of 1 MeV the
halving thickness for concrete is about 44.45 mm and for lead is
about 7.9 mm. Radiation opaque materials can be materials that are
thick or thin so long as they can reduce the radiation that passes
through to the other side. Thus, if it is desired that a particular
enclosure have a low wall thickness, e.g., for light weight or due
to size constraints, the material chosen should have a sufficient Z
value and/or attenuation length so that its halving length is less
than or equal to the desired wall thickness of the enclosure.
[0088] In some cases, the radiation opaque material may be a
layered material, for example, having a layer of a higher Z value
material, to provide good shielding, and a layer of a lower Z value
material to provide other properties (e.g., structural integrity,
impact resistance, etc.). In some cases, the layered material may
be a "graded-Z" laminate, e.g., including a laminate in which the
layers provide a gradient from high-Z through successively lower-Z
elements. In some cases the radiation opaque materials can be
interlocking blocks, for example, lead and/or concrete blocks can
be supplied by NELCO Worldwide (Burlington, Mass.), and
reconfigurable vaults can be utilized.
[0089] A radiation opaque material can reduce the radiation passing
through a structure (e.g., a wall, door, ceiling, enclosure, a
series of these or combinations of these) formed of the material by
about at least about 10%, (e.g., at least about 20%, at least about
30%, at least about 40%, at least about 50%, at least about 60%, at
least about 70%, at least about 80%, at least about 90%, at least
about 95%, at least about 96%, at least about 97%, at least about
98%, at least about 99%, at least about 99.9%, at least about
99.99%, at least about 99.999%) as compared to the incident
radiation. Therefore, an enclosure made of a radiation opaque
material can reduce the exposure of equipment/system/components by
the same amount. Radiation opaque materials can include stainless
steel, metals with Z values above 25 (e.g., lead, iron), concrete,
dirt, sand and combinations thereof. Radiation opaque materials can
include a barrier in the direction of the incident radiation of at
least about 1 mm (e.g., 5 mm, 10 mm, 5 cm, 10 cm, 100 cm, 1 m, 10
m).
Radiation Sources
[0090] The type of radiation determines the kinds of radiation
sources used as well as the radiation devices and associated
equipment. The methods, systems and equipment described herein, for
example, for treating materials with radiation, can utilized
sources as described herein as well as any other useful source.
[0091] Sources of gamma rays include radioactive nuclei, such as
isotopes of cobalt, calcium, technetium, chromium, gallium, indium,
iodine, iron, krypton, samarium, selenium, sodium, thallium, and
xenon.
[0092] Sources of X-rays include electron beam collision with metal
targets, such as tungsten or molybdenum or alloys, or compact light
sources, such as those produced commercially by Lyncean.
[0093] Alpha particles are identical to the nucleus of a helium
atom and are produced by the alpha decay of various radioactive
nuclei, such as isotopes of bismuth, polonium, astatine, radon,
francium, radium, several actinides, such as actinium, thorium,
uranium, neptunium, curium, californium, americium, and
plutonium.
[0094] Sources for ultraviolet radiation include deuterium or
cadmium lamps.
[0095] Sources for infrared radiation include sapphire, zinc, or
selenide window ceramic lamps.
[0096] Sources for microwaves include klystrons, Slevin type RF
sources, or atom beam sources that employ hydrogen, oxygen, or
nitrogen gases.
[0097] Accelerators used to accelerate the particles (e.g.,
electrons or ions) can be DE (e.g., electrostatic DC,
electrodynamic DC), RF linear, magnetic induction linear or
continuous wave. For example, various irradiating devices may be
used in the methods disclosed herein, including field ionization
sources, electrostatic ion separators, field ionization generators,
thermionic emission sources, microwave discharge ion sources,
recirculating or static accelerators, dynamic linear accelerators,
van de Graaff accelerators, Cockroft Walton accelerators (e.g.,
PELLETRON.RTM. accelerators), LINACS, Dynamitrons (e.g,
DYNAMITRON.RTM. accelerators), cyclotrons, synchrotrons, betatrons,
transformer-type accelerators, microtrons, plasma generators,
cascade accelerators, and folded tandem accelerators. For example,
cyclotron type accelerators are available from IBA, Belgium, such
as the RHODOTRON.TM. system, while DC type accelerators are
available from RDI, now IBA Industrial, such as the
DYNAMITRON.RTM.. Other suitable accelerator systems include, for
example: DC insulated core transformer (ICT) type systems,
available from Nissin High Voltage, Japan; S-band LINACs, available
from L3-PSD (USA), Linac Systems (France), Mevex (Canada), and
Mitsubishi Heavy Industries (Japan); L-band LINACs, available from
Iotron Industries (Canada); and ILU-based accelerators, available
from Budker Laboratories (Russia). Ions and ion accelerators are
discussed in Introductory Nuclear Physics, Kenneth S. Krane, John
Wiley & Sons, Inc. (1988), Krsto Prelec, FIZIKA B 6 (1997) 4,
177-206, Chu, William T., "Overview of Light-Ion Beam Therapy",
Columbus-Ohio, ICRU-IAEA Meeting, 18-20 Mar. 2006, Iwata, Y. et
al., "Alternating-Phase-Focused IH-DTL for Heavy-Ion Medical
Accelerators", Proceedings of EPAC 2006, Edinburgh, Scotland, and
Leitner, C. M. et al., "Status of the Superconducting ECR Ion
Source Venus", Proceedings of EPAC 2000, Vienna, Austria. Some
particle accelerators and their uses are disclosed, for example, in
U.S. Pat. No. 7,931,784 to Medoff, the complete disclosure of which
is incorporated herein by reference.
[0098] Electrons may be produced by radioactive nuclei that undergo
beta decay, such as isotopes of iodine, cesium, technetium, and
iridium. Alternatively, an electron gun can be used as an electron
source via thermionic emission and accelerated through an
accelerating potential. An electron gun generates electrons, which
are then accelerated through a large potential (e.g., greater than
about 500 thousand, greater than about 1 million, greater than
about 2 million, greater than about 5 million, greater than about 6
million, greater than about 7 million, greater than about 8
million, greater than about 9 million, or even greater than 10
million volts) and then scanned magnetically in the x-y plane,
where the electrons are initially accelerated in the z direction
down the accelerator tube and extracted through a foil window.
Scanning the electron beams is useful for increasing the
irradiation surface when irradiating materials, e.g., a biomass,
that is conveyed through the scanned beam. Scanning the electron
beam also distributes the thermal load homogenously on the window
and helps reduce the foil window rupture due to local heating by
the electron beam. Window foil rupture is a cause of significant
down-time due to subsequent necessary repairs and re-starting the
electron gun.
[0099] A beam of electrons can be used as the radiation source. A
beam of electrons has the advantages of high dose rates (e.g., 1,
5, or even 10 Mrad per second), high throughput, less containment,
and less confinement equipment. Electron beams can also have high
electrical efficiency (e.g., 80%), allowing for lower energy usage
relative to other radiation methods, which can translate into a
lower cost of operation and lower greenhouse gas emissions
corresponding to the smaller amount of energy used. Electron beams
can be generated, e.g., by electrostatic generators, cascade
generators, transformer generators, low energy accelerators with a
scanning system, low energy accelerators with a linear cathode,
linear accelerators, and pulsed accelerators.
[0100] Electrons can also be more efficient at causing changes in
the molecular structure of carbohydrate-containing materials, for
example, by the mechanism of chain scission. In addition, electrons
having energies of 0.5-10 MeV can penetrate low density materials,
such as the biomass materials described herein, e.g., materials
having a bulk density of less than 0.5 g/cm.sup.3, and a depth of
0.3-10 cm. Electrons as an ionizing radiation source can be useful,
e.g., for relatively thin piles, layers or beds of materials, e.g.,
less than about 0.5 inch, e.g., less than about 0.4 inch, 0.3 inch,
0.25 inch, or less than about 0.1 inch. In some embodiments, the
energy of each electron of the electron beam is from about 0.3 MeV
to about 2.0 MeV (million electron volts), e.g., from about 0.5 MeV
to about 1.5 MeV, or from about 0.7 MeV to about 1.25 MeV. Methods
of irradiating materials are discussed in U.S. Pat. App. Pub.
2012/0100577 A1, filed Oct. 18, 2011, the entire disclosure of
which is herein incorporated by reference.
[0101] Electron beam irradiation devices may be procured
commercially or built. For example, elements or components such
inductors, capacitors, casings, power sources, cables, wiring,
voltage control systems, current control elements, insulating
material, microcontrollers and cooling equipment can be purchased
and assembled into a device. Optionally, a commercial device can be
modified and/or adapted. For example, devices and components can be
purchased from any of the commercial sources described herein
including Ion Beam Applications (Louvain-la-Neuve, Belgium), NHV
Corporation (Japan), the Titan Corporation (San Diego, Calif.),
Vivirad High Voltage Corp (Billerica, Mass.) and/or Budker
Laboratories (Russia). Typical electron energies can be 0.5 MeV, 1
MeV, 2 MeV, 4.5 MeV, 7.5 MeV, or 10 MeV. Typical electron beam
irradiation device power can be 1 kW, 5 kW, 10 kW, 20 kW, 50 kW, 60
kW, 70 kW, 80 kW, 90 kW, 100 kW, 125 kW, 150 kW, 175 kW, 200 kW,
250 kW, 300 kW, 350 kW, 400 kW, 450 kW, 500 kW, 600 kW, 700 kW, 800
kW, 900 kW or even 1000 kW. Accelerators that can be used include
NHV irradiators medium energy series EPS-500 (e.g., 500 kV
accelerator voltage and 65, 100 or 150 mA beam current), EPS-800
(e.g., 800 kV accelerator voltage and 65 or 100 mA beam current),
or EPS-1000 (e.g., 1000 kV accelerator voltage and 65 or 100 mA
beam current). Also, accelerators from NHV's high energy series can
be used such as EPS-1500 (e.g., 1500 kV accelerator voltage and 65
mA beam current), EPS-2000 (e.g., 2000 kV accelerator voltage and
50 mA beam current), EPS-3000 (e.g., 3000 kV accelerator voltage
and 50 mA beam current) and EPS-5000 (e.g., 5000 and 30 mA beam
current).
[0102] Tradeoffs in considering electron beam irradiation device
power specifications include cost to operate, capital costs,
depreciation, and device footprint. Tradeoffs in considering
exposure dose levels of electron beam irradiation would be energy
costs and environment, safety, and health (ESH) concerns.
Typically, generators are housed in a vault, e.g., of lead or
concrete, especially for production from X-rays that are generated
in the process. Tradeoffs in considering electron energies include
energy costs.
[0103] The electron beam irradiation device can produce either a
fixed beam or a scanning beam. A scanning beam may be advantageous
with large scan sweep length and high scan speeds, as this would
effectively replace a large, fixed beam width. Further, available
sweep widths of 0.5 m, 1 m, 2 m or more are available. The scanning
beam is preferred in most embodiments describe herein because of
the larger scan width and reduced possibility of local heating and
failure of the windows.
Electron Guns--Windows
[0104] The extraction system for an electron accelerator can
include two window foils. The cooling gas in the two foil window
extraction system can be a purge gas or a mixture, for example,
air, or a pure gas. In one embodiment the gas is an inert gas such
as nitrogen, argon, helium and or carbon dioxide. It is preferred
to use a gas rather than a liquid since energy losses to the
electron beam are minimized. Mixtures of pure gas can also be used,
either pre-mixed or mixed in line prior to impinging on the windows
or in the space between the windows. The cooling gas can be cooled,
for example, by using a heat exchange system (e.g., a chiller)
and/or by using boil off from a condensed gas (e.g., liquid
nitrogen, liquid helium).
Heating and Throughput During Radiation Treatment
[0105] Several processes can occur in biomass when electrons from
an electron beam interact with matter in inelastic collisions. For
example, ionization of the material, chain scission of polymers in
the material, cross linking of polymers in the material, oxidation
of the material, generation of X-rays ("Bremsstrahlung") and
vibrational excitation of molecules (e.g. phonon generation).
Without being bound to a particular mechanism, the reduction in
recalcitrance can be due to several of these inelastic collision
effects, for example, ionization, chain scission of polymers,
oxidation and phonon generation. Some of the effects (e.g.,
especially X-ray generation), necessitate shielding and engineering
barriers, for example, enclosing the irradiation processes in a
concrete (or other radiation opaque material) vault. Another effect
of irradiation, vibrational excitation, is equivalent to heating up
the sample. Heating the sample by irradiation can help in
recalcitrance reduction, but excessive heating can destroy the
material, as will be explained below.
[0106] The adiabatic temperature rise (.DELTA.T) from adsorption of
ionizing radiation is given by the equation: .DELTA.T=D/Cp: where D
is the average dose in kGy, C.sub.p is the heat capacity in J/g
.degree. C., and .DELTA.T is the change in temperature in .degree.
C. A typical dry biomass material will have a heat capacity close
to 2. Wet biomass will have a higher heat capacity dependent on the
amount of water since the heat capacity of water is very high (4.19
J/g .degree. C.). Metals have much lower heat capacities, for
example, 304 stainless steel has a heat capacity of 0.5 J/g
.degree. C. The temperature change due to the instant adsorption of
radiation in a biomass and stainless steel for various doses of
radiation is shown in Table 1.
TABLE-US-00001 TABLE 1 Calculated Temperature increase for biomass
and stainless steel. Dose (Mrad) Estimated Biomass .DELTA.T
(.degree. C.) Steel .DELTA.T (.degree. C.) 10 50 200 50 250 1000
100 500 2000 150 750 3000 200 1000 4000
[0107] High temperatures can destroy and or modify the biopolymers
in biomass so that the polymers (e.g., cellulose) are unsuitable
for further processing. A biomass subjected to high temperatures
can become dark, sticky and give off odors indicating
decomposition. The stickiness can even make the material hard to
convey. The odors can be unpleasant and be a safety issue. In fact,
keeping the biomass below about 200.degree. C. has been found to be
beneficial in the processes described herein (e.g., below about
190.degree. C., below about 180.degree. C., below about 170.degree.
C., below about 160.degree. C., below about 150.degree. C., below
about 140.degree. C., below about 130.degree. C., below about
120.degree. C., below about 110.degree. C., between about
60.degree. C. and 180.degree. C., between about 60.degree. C. and
160.degree. C., between about 60.degree. C. and 150.degree. C.,
between about 60.degree. C. and 140.degree. C., between about
60.degree. C. and 130.degree. C., between about 60.degree. C. and
120.degree. C., between about 80.degree. C. and 180.degree. C.,
between about 100.degree. C. and 180.degree. C., between about
120.degree. C. and 180.degree. C., between about 140.degree. C. and
180.degree. C., between about 160.degree. C. and 180.degree. C.,
between about 100.degree. C. and 140.degree. C., between about
80.degree. C. and 120.degree. C.).
[0108] It has been found that irradiation above about 10 Mrad is
desirable for the processes described herein (e.g., reduction of
recalcitrance). A high throughput is also desirable so that the
irradiation does not become a bottle neck in processing the
biomass. The treatment is governed by a Dose rate equation:
M=FP/Dtime, where M is the mass of irradiated material (Kg), F is
the fraction of power that is adsorbed (unit less), P is the
emitted power (kW=Voltage in MeV.times.Current in mA), time is the
treatment time (sec) and D is the adsorbed dose (kGy). In an
exemplary process where the fraction of adsorbed power is fixed,
the Power emitted is constant and a set dosage is desired, the
throughput (e.g., M, the biomass processed) can be increased by
increasing the irradiation time. However, increasing the
irradiation time without allowing the material to cool, can
excessively heat the material as exemplified by the calculations
shown above. Since biomass has a low thermal conductivity (less
than about 0.1 Wm.sup.-1K.sup.-1), heat dissipation is slow,
unlike, for example, metals (greater than about 10
Wm.sup.-1K.sup.-1) which can dissipate energy quickly as long as
there is a heat sink to transfer the energy to.
Electron Guns--Beam Stops
[0109] In some embodiments the systems and methods include a beam
stop (e.g., a shutter). For example, the beam stop can be used to
quickly stop or reduce the irradiation of material without powering
down the electron beam device. Alternatively the beam stop can be
used while powering up the electron beam, e.g., the beam stop can
stop the electron beam until a beam current of a desired level is
achieved. The beam stop can be placed between the primary foil
window and a secondary foil window. For example, the beam stop can
be mounted so that it is movable, that is, so that it can be moved
into and out of the beam path. Even partial coverage of the beam
can be used, for example, to control the dose of irradiation. The
beam stop can be mounted to the floor, to a conveyor for the
biomass, to a wall, to the radiation device (e.g., at the scan
horn), or to any structural support. Preferably the beam stop is
fixed in relation to the scan horn so that the beam can be
effectively controlled by the beam stop. The beam stop can
incorporate a hinge, a rail, wheels, slots, or other means allowing
for its operation in moving into and out of the beam. The beam stop
can be made of any material that will stop at least 5% of the
electrons, e.g., at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, at
least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or
even about 100% of the electrons.
[0110] The beam stop can be made of a metal including, but not
limited to, stainless steel, lead, iron, molybdenum, silver, gold,
titanium, aluminum, tin, or alloys of these, or laminates (layered
materials) made with such metals (e.g., metal-coated ceramic,
metal-coated polymer, metal-coated composite, multilayered metal
materials).
[0111] The beam stop can be cooled, for example, with a cooling
fluid such as an aqueous solution or a gas. The beam stop can be
partially or completely hollow, for example, with cavities.
Interior spaces of the beam stop can be used for cooling fluids and
gases. The beam stop can be of any shape, including flat, curved,
round, oval, square, rectangular, beveled and wedged shapes.
[0112] The beam stop can have perforations so as to allow some
electrons through, thus controlling (e.g., reducing) the levels of
radiation across the whole area of the window, or in specific
regions of the window. The beam stop can be a mesh formed, for
example, from fibers or wires. Multiple beam stops can be used,
together or independently, to control the irradiation. The beam
stop can be remotely controlled, e.g., by radio signal or hard
wired to a motor for moving the beam into or out of position.
Beam Dumps
[0113] The embodiments disclosed herein can also include a beam
dump. A beam dump's purpose is to safely absorb a beam of charged
particles. Like a beam stop, a beam dump can be used to block the
beam of charged particles. However, a beam dump is much more robust
than a beam stop, and is intended to block the full power of the
electron beam for an extended period of time. They are often used
to block the beam as the accelerator is powering up.
[0114] Beam dumps are also designed to accommodate the heat
generated by such beams, and are usually made from materials such
as copper, aluminum, carbon, beryllium, tungsten, or mercury. Beam
dumps can be cooled, for example, by using a cooling fluid that is
in thermal contact with the beam dump.
Biomass Materials
[0115] Lignocellulosic materials include, but are not limited to,
wood, particle board, forestry wastes (e.g., sawdust, aspen wood,
wood chips), grasses, (e.g., switchgrass, miscanthus, cord grass,
reed canary grass), grain residues, (e.g., rice hulls, oat hulls,
wheat chaff, barley hulls), agricultural waste (e.g., silage,
canola straw, wheat straw, barley straw, oat straw, rice straw,
jute, hemp, flax, bamboo, sisal, abaca, corn cobs, corn stover,
soybean stover, corn fiber, alfalfa, hay, coconut hair), sugar
processing residues (e.g., bagasse, beet pulp, agave bagasse),
algae, seaweed, manure, sewage, and mixtures of any of these.
[0116] In some cases, the lignocellulosic material includes
corncobs. Ground or hammermilled corncobs can be spread in a layer
of relatively uniform thickness for irradiation, and after
irradiation are easy to disperse in the medium for further
processing. To facilitate harvest and collection, in some cases the
entire corn plant is used, including the corn stalk, corn kernels,
and in some cases even the root system of the plant.
[0117] Advantageously, no additional nutrients (other than a
nitrogen source, e.g., urea or ammonia) are required during
fermentation of corncobs or cellulosic or lignocellulosic materials
containing significant amounts of corncobs.
[0118] Corncobs, before and after comminution, are also easier to
convey and disperse, and have a lesser tendency to form explosive
mixtures in air than other cellulosic or lignocellulosic materials
such as hay and grasses.
[0119] Cellulosic materials include, for example, paper, paper
products, paper waste, paper pulp, pigmented papers, loaded papers,
coated papers, filled papers, magazines, printed matter (e.g.,
books, catalogs, manuals, labels, calendars, greeting cards,
brochures, prospectuses, newsprint), printer paper, polycoated
paper, card stock, cardboard, paperboard, materials having a high
.alpha.-cellulose content such as cotton, and mixtures of any of
these. For example, paper products as described in U.S. application
Ser. No. 13/396,365 ("Magazine Feedstocks" by Medoff et al., filed
Feb. 14, 2012), the full disclosure of which is incorporated herein
by reference.
[0120] Cellulosic materials can also include lignocellulosic
materials which have been partially or fully de-lignified.
[0121] In some instances other biomass materials can be utilized,
for example, starchy materials. Starchy materials include starch
itself, e.g., corn starch, wheat starch, potato starch or rice
starch, a derivative of starch, or a material that includes starch,
such as an edible food product or a crop. For example, the starchy
material can be arracacha, buckwheat, banana, barley, cassava,
kudzu, ocra, sago, sorghum, regular household potatoes, sweet
potato, taro, yams, or one or more beans, such as favas, lentils or
peas. Blends of any two or more starchy materials are also starchy
materials. Mixtures of starchy, cellulosic and or lignocellulosic
materials can also be used. For example, a biomass can be an entire
plant, a part of a plant or different parts of a plant, e.g., a
wheat plant, cotton plant, a corn plant, rice plant or a tree. The
starchy materials can be treated by any of the methods described
herein.
[0122] Microbial materials that can be used as feedstock can
include, but are not limited to, any naturally occurring or
genetically modified microorganism or organism that contains or is
capable of providing a source of carbohydrates (e.g., cellulose),
for example, protists, e.g., animal protists (e.g., protozoa such
as flagellates, amoeboids, ciliates, and sporozoa) and plant
protists (e.g., algae such alveolates, chlorarachniophytes,
cryptomonads, euglenids, glaucophytes, haptophytes, red algae,
stramenopiles, and viridaeplantae). Other examples include seaweed,
plankton (e.g., macroplankton, mesoplankton, microplankton,
nanoplankton, picoplankton, and femtoplankton), phytoplankton,
bacteria (e.g., gram positive bacteria, gram negative bacteria, and
extremophiles), yeast and/or mixtures of these. In some instances,
microbial biomass can be obtained from natural sources, e.g., the
ocean, lakes, bodies of water, e.g., salt water or fresh water, or
on land. Alternatively or in addition, microbial biomass can be
obtained from culture systems, e.g., large scale dry and wet
culture and fermentation systems.
[0123] In other embodiments, the biomass materials, such as
cellulosic, starchy and lignocellulosic feedstock materials, can be
obtained from transgenic microorganisms and plants that have been
modified with respect to a wild type variety. Such modifications
may be, for example, through the iterative steps of selection and
breeding to obtain desired traits in a plant. Furthermore, the
plants can have had genetic material removed, modified, silenced
and/or added with respect to the wild type variety. For example,
genetically modified plants can be produced by recombinant DNA
methods, where genetic modifications include introducing or
modifying specific genes from parental varieties, or, for example,
by using transgenic breeding wherein a specific gene or genes are
introduced to a plant from a different species of plant and/or
bacteria. Another way to create genetic variation is through
mutation breeding wherein new alleles are artificially created from
endogenous genes. The artificial genes can be created by a variety
of ways including treating the plant or seeds with, for example,
chemical mutagens (e.g., using alkylating agents, epoxides,
alkaloids, peroxides, formaldehyde), irradiation (e.g., X-rays,
gamma rays, neutrons, beta particles, alpha particles, protons,
deuterons, UV radiation) and temperature shocking or other external
stressing and subsequent selection techniques. Other methods of
providing modified genes is through error prone PCR and DNA
shuffling followed by insertion of the desired modified DNA into
the desired plant or seed. Methods of introducing the desired
genetic variation in the seed or plant include, for example, the
use of a bacterial carrier, biolistics, calcium phosphate
precipitation, electroporation, gene splicing, gene silencing,
lipofection, microinjection and viral carriers. Additional
genetically modified materials have been described in U.S.
application Ser. No. 13/396,369 filed Feb. 14, 2012 the full
disclosure of which is incorporated herein by reference.
[0124] Any of the methods described herein can be practiced with
mixtures of any biomass materials described herein.
Other Materials
[0125] Other materials (e.g., natural or synthetic materials), for
example, polymers, can be treated and/or made utilizing the
methods, equipment and systems described herein. For example,
polyethylene (e.g., linear low density ethylene and high density
polyethylene), polystyrenes, sulfonated polystyrenes, poly (vinyl
chloride), polyesters (e.g., nylons, DACRON.TM., KODEL.TM.),
polyalkylene esters, poly vinyl esters, polyamides (e.g.,
KEVLAR.TM.) polyethylene terephthalate, cellulose acetate, acetal,
poly acrylonitrile, polycarbonates (e.g., LEXAN.TM.), acrylics
[e.g., poly (methyl methacrylate), poly(methyl methacrylate),
polyacrylnitriles], Poly urethanes, polypropylene, poly butadiene,
polyisobutylene, polyacrylonitrile, polychloroprene (e.g.
neoprene), poly(cis-1,4-isoprene) [e.g., natural rubber],
poly(trans-1,4-isoprene) [e.g., gutta percha], phenol formaldehyde,
melamine formaldehyde, epoxides, polyesters, poly amines,
polycarboxylic acids, polylactic acids, polyvinyl alcohols,
polyanhydrides, poly fluoro carbons (e.g., TEFLON.TM.), silicons
(e.g., silicone rubber), polysilanes, poly ethers (e.g.,
polyethylene oxide, polypropylene oxide), waxes, oils and mixtures
of these. Also included are plastics, rubbers, elastomers, fibers,
waxes, gels, oils, adhesives, thermoplastics, thermosets,
biodegradable polymers, resins made with these polymers, other
polymers, other materials and combinations thereof. The polymers
can be made by any useful method including cationic polymerization,
anionic polymerization, radical polymerization, metathesis
polymerization, ring opening polymerization, graft polymerization,
addition polymerization. In some cases the treatments disclosed
herein can be used, for example, for radically initiated graft
polymerization and cross linking. Composites of polymers, for
example, with glass, metals, biomass (e.g., fibers, particles),
ceramics can also be treated and/or made.
[0126] Other materials that can be treated by using the methods,
systems and equipment disclosed herein are ceramic materials,
minerals, metals, inorganic compounds. For example, silicon and
germanium crystals, silicon nitrides, metal oxides, semiconductors,
insulators, cements and or conductors.
[0127] In addition, manufactured multipart or shaped materials
(e.g., molded, extruded, welded, riveted, layered or combined in
any way) can be treated, for example, cables, pipes, boards,
enclosures, integrated semiconductor chips, circuit boards, wires,
tires, windows, laminated materials, gears, belts, machines,
combinations of these. For example, treating a material by the
methods described herein can modify the surfaces, for example,
making them susceptible to further functionalization, combinations
(e.g., welding) and/or treatment can cross link the materials.
Biomass Material Preparation--Mechanical Treatments
[0128] The biomass can be in a dry form, for example, with less
than about 35% moisture content (e.g., less than about 20%, less
than about 15%, less than about 10% less than about 5%, less than
about 4%, less than about 3%, less than about 2% or even less than
about 1%). The biomass can also be delivered in a wet state, for
example, as a wet solid, a slurry or a suspension with at least
about 10 wt. % solids (e.g., at least about 20 wt. %, at least
about 30 wt. %, at least about 40 wt. %, at least about 50 wt. %,
at least about 60 wt. %, at least about 70 wt. %).
[0129] The material to be processed, e.g., biomass material, can be
a particulate material. For example, with an average particle size
above at least about 0.25 mm (e.g., at least about 0.5 mm, at least
about 0.75 mm) and below about 6 mm (e.g., below about 3 mm, below
about 2 mm). In some embodiments this is produced by mechanical
means, for example, as described herein.
[0130] The processes disclosed herein can utilize low bulk density
materials, for example, cellulosic or lignocellulosic feedstocks
that have been physically pretreated to have a bulk density of less
than about 0.75 g/cm.sup.3, e.g., less than about 0.7, 0.65, 0.60,
0.50, 0.35, 0.25, 0.20, 0.15, 0.10, 0.05 or less, e.g., less than
about 0.025 g/cm.sup.3. Bulk density is determined using ASTM
D1895B. Briefly, the method involves filling a measuring cylinder
of known volume with a sample and obtaining a weight of the sample.
The bulk density is calculated by dividing the weight of the sample
in grams by the known volume of the cylinder in cubic centimeters.
If desired, low bulk density materials can be densified, for
example, by methods described in U.S. Pat. No. 7,971,809 published
Jul. 5, 2011, the entire disclosure of which is hereby incorporated
by reference.
[0131] In some cases, the pre-treatment processing includes
screening of the biomass material. Screening can be through a mesh
or perforated plate with a desired opening size, for example, less
than about 6.35 mm (1/4 inch, 0.25 inch), (e.g., less than about
3.18 mm (1/8 inch, 0.125 inch), less than about 1.59 mm ( 1/16
inch, 0.0625 inch), is less than about 0.79 mm ( 1/32 inch, 0.03125
inch), e.g., less than about 0.51 mm ( 1/50 inch, 0.02000 inch),
less than about 0.40 mm ( 1/64 inch, 0.015625 inch), less than
about 0.23 mm (0.009 inch), less than about 0.20 mm ( 1/128 inch,
0.0078125 inch), less than about 0.18 mm (0.007 inch), less than
about 0.13 mm (0.005 inch), or even less than about 0.10 mm ( 1/256
inch, 0.00390625 inch)). In one configuration the desired biomass
falls through the perforations or screen and thus biomass larger
than the perforations or screen are not irradiated. These larger
materials can be re-processed, for example, by comminuting, or they
can simply be removed from processing. In another configuration
material that is larger than the perforations is irradiated and the
smaller material is removed by the screening process or recycled.
In this kind of a configuration, the conveyor, such as a vibratory
conveyor, itself (for example, a part of the conveyor) can be
perforated or made with a mesh. For example, in one particular
embodiment the biomass material may be wet and the perforations or
mesh allow water to drain away from the biomass before
irradiation.
[0132] Screening of material can also be by a manual method, for
example, by an operator or mechanoid (e.g., a robot equipped with a
color, reflectivity or other sensor) that removes unwanted
material. Screening can also be by magnetic screening wherein a
magnet is disposed near the conveyed material and the magnetic
material is removed magnetically.
[0133] Optional pre-treatment processing can include heating the
material. For example, a portion of a conveyor conveying the
biomass or other material can be sent through a heated zone. The
heated zone can be created, for example, by IR radiation,
microwaves, combustion (e.g., gas, coal, oil, biomass), resistive
heating and/or inductive coils. The heat can be applied from at
least one side or more than one side, can be continuous or periodic
and can be for only a portion of the material or all the material.
For example, a portion of the conveying trough can be heated by use
of a heating jacket. Heating can be, for example, for the purpose
of drying the material. In the case of drying the material, this
can also be facilitated, with or without heating, by the movement
of a gas (e.g., air, oxygen, nitrogen, He, CO.sub.2, Argon) over
and/or through the biomass as it is being conveyed.
[0134] Optionally, pre-treatment processing can include cooling the
material. Cooling material is described in U.S. Pat. No. 7,900,857
published Mar. 8, 2011, the disclosure of which in incorporated
herein by reference. For example, cooling can be by supplying a
cooling fluid, for example, water (e.g., with glycerol), or
nitrogen (e.g., liquid nitrogen) to the bottom of the conveying
trough. Alternatively, a cooling gas, for example, chilled nitrogen
can be blown over the biomass materials or under the conveying
system.
[0135] Another optional pre-treatment processing method can include
adding a material to the biomass or other feedstocks. The
additional material can be added by, for example, by showering,
sprinkling and or pouring the material onto the biomass as it is
conveyed. Materials that can be added include, for example, metals,
ceramics and/or ions as described in U.S. Patent App. Pub.
2010/0105119 A1 (filed Oct. 26, 2009) and U.S. Patent App. Pub.
2010/0159569 A1 (filed Dec. 16, 2009), the entire disclosures of
which are incorporated herein by reference. Optional materials that
can be added include acids and bases. Other materials that can be
added are oxidants (e.g., peroxides, chlorates), polymers,
polymerizable monomers (e.g., containing unsaturated bonds), water,
catalysts, enzymes and/or organisms. Materials can be added, for
example, in pure form, as a solution in a solvent (e.g., water or
an organic solvent) and/or as a solution. In some cases the solvent
is volatile and can be made to evaporate e.g., by heating and/or
blowing gas as previously described. The added material may form a
uniform coating on the biomass or be a homogeneous mixture of
different components (e.g., biomass and additional material). The
added material can modulate the subsequent irradiation step by
increasing the efficiency of the irradiation, damping the
irradiation or changing the effect of the irradiation (e.g., from
electron beams to X-rays or heat). The method may have no impact on
the irradiation but may be useful for further downstream
processing. The added material may help in conveying the material,
for example, by lowering dust levels.
[0136] Biomass can be delivered to conveyor (e.g., vibratory
conveyors that can be used in the vaults herein described) by a
belt conveyor, a pneumatic conveyor, a screw conveyor, a hopper, a
pipe, manually or by a combination of these. The biomass can, for
example, be dropped, poured and/or placed onto the conveyor by any
of these methods. In some embodiments the material is delivered to
the conveyor using an enclosed material distribution system to help
maintain a low oxygen atmosphere and/or control dust and fines.
Lofted or air suspended biomass fines and dust are undesirable
because these can form an explosion hazard or damage the window
foils of an electron gun (if such a device is used for treating the
material).
[0137] The material can be leveled to form a uniform thickness
between about 0.0312 and 5 inches (e.g., between about 0.0625 and
2.000 inches, between about 0.125 and 1 inches, between about 0.125
and 0.5 inches, between about 0.3 and 0.9 inches, between about 0.2
and 0.5 inches between about 0.25 and 1.0 inches, between about
0.25 and 0.5 inches, 0.100+/-0.025 inches, 0.150+/-0.025 inches,
0.200+/-0.025 inches, 0.250+/-0.025 inches, 0.300+/-0.025 inches,
0.350+/-0.025 inches, 0.400+/-0.025 inches, 0.450+/-0.025 inches,
0.500+/-0.025 inches, 0.550+/-0.025 inches, 0.600+/-0.025 inches,
0.700+/-0.025 inches, 0.750+/-0.025 inches, 0.800+/-0.025 inches,
0.850+/-0.025 inches, 0.900+/-0.025 inches, 0.900+/-0.025
inches.
[0138] Generally, it is preferred to convey the material as quickly
as possible through the electron beam to maximize throughput. For
example, the material can be conveyed at rates of at least 1
ft/min, e.g., at least 2 ft/min, at least 3 ft/min, at least 4
ft/min, at least 5 ft/min, at least 10 ft/min, at least 15 ft/min,
20, 25, 30, 35, 40, 45, 50 ft/min. The rate of conveying is related
to the beam current, for example, for a 1/4 inch thick biomass and
100 mA, the conveyor can move at about 20 ft/min to provide a
useful irradiation dosage, at 50 mA the conveyor can move at about
10 ft/min to provide approximately the same irradiation dosage.
[0139] After the biomass material has been conveyed through the
radiation zone, optional post-treatment processing can be done. The
optional post-treatment processing can, for example, be a process
described with respect to the pre-irradiation processing. For
example, the biomass can be screened, heated, cooled, and/or
combined with additives. Uniquely to post-irradiation, quenching of
the radicals can occur, for example, quenching of radicals by the
addition of fluids or gases (e.g., oxygen, nitrous oxide, ammonia,
liquids), using pressure, heat, and/or the addition of radical
scavengers. For example, the biomass can be conveyed out of the
enclosed conveyor and exposed to a gas (e.g., oxygen) where it is
quenched, forming carboxylated groups. In one embodiment the
biomass is exposed during irradiation to the reactive gas or fluid.
Quenching of biomass that has been irradiated is described in U.S.
Pat. No. 8,083,906 published Dec. 27, 2011, the entire disclosure
of which is incorporate herein by reference.
[0140] If desired, one or more mechanical treatments can be used in
addition to irradiation to further reduce the recalcitrance of the
carbohydrate-containing material. These processes can be applied
before, during and or after irradiation.
[0141] In some cases, the mechanical treatment may include an
initial preparation of the feedstock as received, e.g., size
reduction of materials, such as by comminution, e.g., cutting,
grinding, shearing, pulverizing or chopping. For example, in some
cases, loose feedstock (e.g., recycled paper, starchy materials, or
switchgrass) is prepared by shearing or shredding. Mechanical
treatment may reduce the bulk density of the
carbohydrate-containing material, increase the surface area of the
carbohydrate-containing material and/or decrease one or more
dimensions of the carbohydrate-containing material.
[0142] Alternatively, or in addition, the feedstock material can be
treated with another treatment, for example, chemical treatments,
such as with an acid (HCl, H.sub.2SO.sub.4, H.sub.3PO.sub.4), a
base (e.g., KOH and NaOH), a chemical oxidant (e.g., peroxides,
chlorates, ozone), irradiation, steam explosion, pyrolysis,
sonication, oxidation, chemical treatment. The treatments can be in
any order and in any sequence and combinations. For example, the
feedstock material can first be physically treated by one or more
treatment methods, e.g., chemical treatment including and in
combination with acid hydrolysis (e.g., utilizing HCl,
H.sub.2SO.sub.4, H.sub.3PO.sub.4), radiation, sonication,
oxidation, pyrolysis or steam explosion, and then mechanically
treated. This sequence can be advantageous since materials treated
by one or more of the other treatments, e.g., irradiation or
pyrolysis, tend to be more brittle and, therefore, it may be easier
to further change the structure of the material by mechanical
treatment. As another example, a feedstock material can be conveyed
through ionizing radiation using a conveyor as described herein and
then mechanically treated. Chemical treatment can remove some or
all of the lignin (for example, chemical pulping) and can partially
or completely hydrolyze the material. The methods also can be used
with pre-hydrolyzed material. The methods also can be used with
material that has not been pre hydrolyzed The methods can be used
with mixtures of hydrolyzed and non-hydrolyzed materials, for
example, with about 50% or more non-hydrolyzed material, with about
60% or more non-hydrolyzed material, with about 70% or more
non-hydrolyzed material, with about 80% or more non-hydrolyzed
material or even with 90% or more non-hydrolyzed material.
[0143] In addition to size reduction, which can be performed
initially and/or later in processing, mechanical treatment can also
be advantageous for "opening up," "stressing," breaking or
shattering the carbohydrate-containing materials, making the
cellulose of the materials more susceptible to chain scission
and/or disruption of crystalline structure during the physical
treatment.
[0144] Methods of mechanically treating the carbohydrate-containing
material include, for example, milling or grinding. Milling may be
performed using, for example, a hammer mill, ball mill, colloid
mill, conical or cone mill, disk mill, edge mill, Wiley mill, grist
mill or other mill. Grinding may be performed using, for example, a
cutting/impact type grinder. Some exemplary grinders include stone
grinders, pin grinders, coffee grinders, and burr grinders.
Grinding or milling may be provided, for example, by a
reciprocating pin or other element, as is the case in a pin mill.
Other mechanical treatment methods include mechanical ripping or
tearing, other methods that apply pressure to the fibers, and air
attrition milling. Suitable mechanical treatments further include
any other technique that continues the disruption of the internal
structure of the material that was initiated by the previous
processing steps.
[0145] Mechanical feed preparation systems can be configured to
produce streams with specific characteristics such as, for example,
specific maximum sizes, specific length-to-width, or specific
surface areas ratios. Physical preparation can increase the rate of
reactions, improve the movement of material on a conveyor, improve
the irradiation profile of the material, improve the radiation
uniformity of the material, or reduce the processing time required
by opening up the materials and making them more accessible to
processes and/or reagents, such as reagents in a solution.
[0146] The bulk density of feedstocks can be controlled (e.g.,
increased). In some situations, it can be desirable to prepare a
low bulk density material, e.g., by densifying the material (e.g.,
densification can make it easier and less costly to transport to
another site) and then reverting the material to a lower bulk
density state (e.g., after transport). The material can be
densified, for example, from less than about 0.2 g/cc to more than
about 0.9 g/cc (e.g., less than about 0.3 to more than about 0.5
g/cc, less than about 0.3 to more than about 0.9 g/cc, less than
about 0.5 to more than about 0.9 g/cc, less than about 0.3 to more
than about 0.8 g/cc, less than about 0.2 to more than about 0.5
g/cc). For example, the material can be densified by the methods
and equipment disclosed in U.S. Pat. No. 7,932,065 to Medoff and
International Publication No. WO 2008/073186 (which was filed Oct.
26, 2007, was published in English, and which designated the United
States), the full disclosures of which are incorporated herein by
reference. Densified materials can be processed by any of the
methods described herein, or any material processed by any of the
methods described herein can be subsequently densified.
[0147] In some embodiments, the material to be processed is in the
form of a fibrous material that includes fibers provided by
shearing a fiber source. For example, the shearing can be performed
with a rotary knife cutter.
[0148] For example, a fiber source, e.g., that is recalcitrant or
that has had its recalcitrance level reduced, can be sheared, e.g.,
in a rotary knife cutter, to provide a first fibrous material. The
first fibrous material is passed through a first screen, e.g.,
having an average opening size of 1.59 mm or less ( 1/16 inch,
0.0625 inch), provide a second fibrous material. If desired, the
fiber source can be cut prior to the shearing, e.g., with a
shredder. For example, when a paper is used as the fiber source,
the paper can be first cut into strips that are, e.g., 1/4- to
1/2-inch wide, using a shredder, e.g., a counter-rotating screw
shredder, such as those manufactured by Munson (Utica, N.Y.). As an
alternative to shredding, the paper can be reduced in size by
cutting to a desired size using a guillotine cutter. For example,
the guillotine cutter can be used to cut the paper into sheets that
are, e.g., 10 inches wide by 12 inches long.
[0149] In some embodiments, the shearing of the fiber source and
the passing of the resulting first fibrous material through a first
screen are performed concurrently. The shearing and the passing can
also be performed in a batch-type process.
[0150] For example, a rotary knife cutter can be used to
concurrently shear the fiber source and screen the first fibrous
material. A rotary knife cutter includes a hopper that can be
loaded with a shredded fiber source prepared by shredding a fiber
source.
[0151] In some implementations, the feedstock is physically treated
prior to saccharification and/or fermentation. Physical treatment
processes can include one or more of any of those described herein,
such as mechanical treatment, chemical treatment, irradiation,
sonication, oxidation, pyrolysis or steam explosion. Treatment
methods can be used in combinations of two, three, four, or even
all of these technologies (in any order). When more than one
treatment method is used, the methods can be applied at the same
time or at different times. Other processes that change a molecular
structure of a biomass feedstock may also be used, alone or in
combination with the processes disclosed herein.
[0152] Mechanical treatments that may be used, and the
characteristics of the mechanically treated carbohydrate-containing
materials, are described in further detail in U.S. Patent Pub.
2012/0100577 A1, filed Oct. 18, 2011, the full disclosure of which
is hereby incorporated herein by reference.
Sonication, Pyrolysis, Oxidation, Steam Explosion, Heating
[0153] If desired, one or more sonication, pyrolysis, oxidation,
heating or steam explosion processes can be used instead of or in
addition to irradiation to reduce or further reduce the
recalcitrance of the carbohydrate-containing material. For example,
these processes can be applied before, during and or after
irradiation. These processes are described in detail in U.S. Pat.
No. 7,932,065 to Medoff, the full disclosure of which is
incorporated herein by reference.
[0154] Alternatively, the biomass can be heated after the biomass
is treated by one or more of sonication, pyrolysis, oxidation,
radiation and steam explosion processes. For example, the biomass
can be heated after the biomass is irradiated prior to a
saccharification step. The heating can be created, for example, by
IR radiation, microwaves, combustion (e.g., gas, coal, oil, and/or
biomass), resistive heating and/or inductive coils. This heating
can be in a liquid, for example, in water or other water-based
solvents. The heat can be applied from at least one side or more
than one side, can be continuous or periodic and can be for only a
portion of the material or all the material. The biomass can be
heated to temperatures above about 90 deg C. in an aqueous liquid
that may have an acid or a base present. For example, the aqueous
biomass slurry can be heated to between about 90 and 150 deg C.
(e.g., between about 105-145 deg C., between about 110 to 140 deg
C., or 115-135 deg C.). The time that the aqueous biomass mixture
is held at the targeted temperature range is 1 to 12 hours (e.g., 1
to 6 hours, 1 to 4 hours). In some instances, the aqueous biomass
mixture is alkaline and the pH is between 6 and 13 (e.g., 8-12, or
8-11)
Intermediates and Products
[0155] Using the processes described herein, the biomass material
can be converted to one or more products, such as energy, fuels,
foods and materials. For example, intermediates and products such
as organic acids, salts of organic acids, anhydrides, esters of
organic acids and fuels, e.g., fuels for internal combustion
engines or feedstocks for fuel cells can be produced. Systems and
processes are described herein that can use as feedstock cellulosic
and/or lignocellulosic materials that are readily available, but
often can be difficult to process, e.g., municipal waste streams
and waste paper streams, such as streams that include newspaper,
kraft paper, corrugated paper or mixtures of these.
[0156] Specific examples of products include, but are not limited
to, hydrogen, sugars (e.g., glucose, xylose, arabinose, mannose,
galactose, fructose, disaccharides, oligosaccharides and
polysaccharides), alcohols (e.g., monohydric alcohols or dihydric
alcohols, such as ethanol, n-propanol, isobutanol, sec-butanol,
tert-butanol or n-butanol), hydrated or hydrous alcohols (e.g.,
containing greater than 10%, 20%, 30% or even greater than 40%
water), biodiesel, organic acids, hydrocarbons (e.g., methane,
ethane, propane, isobutene, pentane, n-hexane, biodiesel,
bio-gasoline and mixtures thereof), co-products (e.g., proteins,
such as cellulolytic proteins (enzymes) or single cell proteins),
and mixtures of any of these in any combination or relative
concentration, and optionally in combination with any additives
(e.g., fuel additives). Other examples include carboxylic acids,
salts of a carboxylic acid, a mixture of carboxylic acids and salts
of carboxylic acids and esters of carboxylic acids (e.g., methyl,
ethyl and n-propyl esters), ketones (e.g., acetone), aldehydes
(e.g., acetaldehyde), alpha and beta unsaturated acids (e.g.,
acrylic acid) and olefins (e.g., ethylene). Other alcohols and
alcohol derivatives include propanol, propylene glycol,
1,4-butanediol, 1,3-propanediol, sugar alcohols (e.g., erythritol,
glycol, glycerol, sorbitol threitol, arabitol, ribitol, mannitol,
dulcitol, fucitol, iditol, isomalt, maltitol, lactitol, xylitol and
other polyols), and methyl or ethyl esters of any of these
alcohols. Other products include methyl acrylate,
methylmethacrylate, lactic acid, citric acid, formic acid, acetic
acid, propionic acid, butyric acid, succinic acid, valeric acid,
caproic acid, 3-hydroxypropionic acid, palmitic acid, stearic acid,
oxalic acid, malonic acid, glutaric acid, oleic acid, linoleic
acid, glycolic acid, gamma-hydroxybutyric acid, and mixtures
thereof, salts of any of these acids, mixtures of any of the acids
and their respective salts.
[0157] Any combination of the above products with each other,
and/or of the above products with other products, which other
products may be made by the processes described herein or
otherwise, may be packaged together and sold as products. The
products may be combined, e.g., mixed, blended or co-dissolved, or
may simply be packaged or sold together.
[0158] Any of the products or combinations of products described
herein may be sanitized or sterilized prior to selling the
products, e.g., after purification or isolation or even after
packaging, to neutralize one or more potentially undesirable
contaminants that could be present in the product(s). Such
sanitation can be done with electron bombardment, for example, by
at a dosage of less than about 20 Mrad, e.g., from about 0.1 to 15
Mrad, from about 0.5 to 7 Mrad, or from about 1 to 3 Mrad.
[0159] The processes described herein can produce various
by-product streams useful for generating steam and electricity to
be used in other parts of the plant (co-generation) or sold on the
open market. For example, steam generated from burning by-product
streams can be used in a distillation process. As another example,
electricity generated from burning by-product streams can be used
to power electron beam generators used in pretreatment.
[0160] The by-products used to generate steam and electricity are
derived from a number of sources throughout the process. For
example, anaerobic digestion of wastewater can produce a biogas
high in methane and a small amount of waste biomass (sludge). As
another example, post-saccharification and/or post-distillate
solids (e.g., unconverted lignin, cellulose, and hemicellulose
remaining from the pretreatment and primary processes) can be used,
e.g., burned, as a fuel.
[0161] Other intermediates and products, including food and
pharmaceutical products, are described in U.S. Patent Pub.
2010/0124583 A1, published May 20, 2010, to Medoff, the full
disclosure of which is hereby incorporated by reference herein.
Lignin Derived Products
[0162] The spent biomass (e.g., spent lignocellulosic material)
from lignocellulosic processing by the methods described are
expected to have a high lignin content and in addition to being
useful for producing energy through combustion in a Co-Generation
plant, may have uses as other valuable products. For example, the
lignin can be used as captured as a plastic, or it can be
synthetically upgraded to other plastics. In some instances, it can
also be converted to lignosulfonates, which can be utilized as
binders, dispersants, emulsifiers or as sequestrants. When used as
a binder, the lignin or a lignosulfonate can, e.g., be utilized in
coal briquettes, in ceramics, for binding carbon black, for binding
fertilizers and herbicides, as a dust suppressant, in the making of
plywood and particle board, for binding animal feeds, as a binder
for fiberglass, as a binder in linoleum paste and as a soil
stabilizer.
[0163] When used as a dispersant, the lignin or lignosulfonates can
be used, e.g., concrete mixes, clay and ceramics, dyes and
pigments, leather tanning and in gypsum board.
[0164] When used as an emulsifier, the lignin or lignosulfonates
can be used, e.g., in asphalt, pigments and dyes, pesticides and
wax emulsions.
[0165] When used as a sequestrant, the lignin or lignosulfonates
can be used, e.g., in micro-nutrient systems, cleaning compounds
and water treatment systems, e.g., for boiler and cooling
systems.
[0166] For energy production lignin generally has a higher energy
content than holocellulose (cellulose and hemicellulose) since it
contains more carbon than homocellulose. For example, dry lignin
can have an energy content of between about 11,000 and 12,500 BTU
per pound, compared to 7,000 an 8,000 BTU per pound of
holocellulose. As such, lignin can be densified and converted into
briquettes and pellets for burning. For example, the lignin can be
converted into pellets by any method described herein. For a slower
burning pellet or briquette, the lignin can be crosslinked, such as
applying a radiation dose of between about 0.5 Mrad and 5 Mrad.
Crosslinking can make a slower burning form factor. The form
factor, such as a pellet or briquette, can be converted to a
"synthetic coal" or charcoal by pyrolyzing in the absence of air,
e.g., at between 400 and 950.degree. C. Prior to pyrolyzing, it can
be desirable to crosslink the lignin to maintain structural
integrity.
Saccharification
[0167] In order to convert the feedstock to a form that can be
readily processed the glucan- or xylan-containing cellulose in the
feedstock can be hydrolyzed to low molecular weight carbohydrates,
such as sugars, by a saccharifying agent, e.g., an enzyme or acid,
a process referred to as saccharification. The low molecular weight
carbohydrates can then be used, for example, in an existing
manufacturing plant, such as a single cell protein plant, an enzyme
manufacturing plant, or a fuel plant, e.g., an ethanol
manufacturing facility.
[0168] The feedstock can be hydrolyzed using an enzyme, e.g., by
combining the materials and the enzyme in a solvent, e.g., in an
aqueous solution.
[0169] Alternatively, the enzymes can be supplied by organisms that
break down biomass, such as the cellulose and/or the lignin
portions of the biomass, contain or manufacture various
cellulolytic enzymes (cellulases), ligninases or various small
molecule biomass-degrading metabolites. These enzymes may be a
complex of enzymes that act synergistically to degrade crystalline
cellulose or the lignin portions of biomass. Examples of
cellulolytic enzymes include: endoglucanases, cellobiohydrolases,
and cellobiases (beta-glucosidases).
[0170] During saccharification a cellulosic substrate can be
initially hydrolyzed by endoglucanases at random locations
producing oligomeric intermediates. These intermediates are then
substrates for exo-splitting glucanases such as cellobiohydrolase
to produce cellobiose from the ends of the cellulose polymer.
Cellobiose is a water-soluble 1,4-linked dimer of glucose. Finally,
cellobiase cleaves cellobiose to yield glucose. The efficiency
(e.g., time to hydrolyze and/or completeness of hydrolysis) of this
process depends on the recalcitrance of the cellulosic
material.
[0171] Therefore, the treated biomass materials can be
saccharified, by combining the material and a cellulase enzyme in a
fluid medium, e.g., an aqueous solution. In some cases, the
material is boiled, steeped, or cooked in hot water prior to
saccharification, as described in U.S. Patent Pub. 2012/0100577 A1
by Medoff and Masterman, published on Apr. 26, 2012, the entire
contents of which are incorporated herein.
[0172] The saccharification process can be partially or completely
performed in a tank (e.g., a tank having a volume of at least 4000,
40,000, or 500,000 L) in a manufacturing plant, and/or can be
partially or completely performed in transit, e.g., in a rail car,
tanker truck, or in a supertanker or the hold of a ship. The time
required for complete saccharification will depend on the process
conditions and the carbohydrate-containing material and enzyme
used. If saccharification is performed in a manufacturing plant
under controlled conditions, the cellulose may be substantially
entirely converted to sugar, e.g., glucose in about 12-96 hours. If
saccharification is performed partially or completely in transit,
saccharification may take longer.
[0173] It is generally preferred that the tank contents be mixed
during saccharification, e.g., using jet mixing as described in
International App. No. PCT/US2010/035331, filed May 18, 2010, which
was published in English as WO 2010/135380 and designated the
United States, the full disclosure of which is incorporated by
reference herein.
[0174] The addition of surfactants can enhance the rate of
saccharification. Examples of surfactants include non-ionic
surfactants, such as a Tween.RTM. 20 or Tween.RTM. 80 polyethylene
glycol surfactants, ionic surfactants, or amphoteric
surfactants.
[0175] It is generally preferred that the concentration of the
sugar solution resulting from saccharification be relatively high,
e.g., greater than 40%, or greater than 50, 60, 70, 80, 90 or even
greater than 95% by weight. Water may be removed, e.g., by
evaporation, to increase the concentration of the sugar solution.
This reduces the volume to be shipped, and also inhibits microbial
growth in the solution.
[0176] Alternatively, sugar solutions of lower concentrations may
be used, in which case it may be desirable to add an antimicrobial
additive, e.g., a broad spectrum antibiotic, in a low
concentration, e.g., 50 to 150 ppm. Other suitable antibiotics
include amphotericin B, ampicillin, chloramphenicol, ciprofloxacin,
gentamicin, hygromycin B, kanamycin, neomycin, penicillin,
puromycin, streptomycin. For example, antimicrobials from Lallemand
Biofuels and Distilled Spirits (Montreal, Quebec, Canada) can be
used such as LACTOSIDE V.TM., BACTENIX.RTM. V300, BACTENIX.RTM.
V300SP, ALLPEN.TM. SPECIAL, BACTENIX.RTM. V60, BACTENIX.RTM. V60SP,
BACTENIX.RTM. V50 and/or LACTOSIDE 247.TM.. Antibiotics will
inhibit growth of microorganisms during transport and storage, and
can be used at appropriate concentrations, e.g., between 15 and
1000 ppm by weight, e.g., between 25 and 500 ppm, or between 50 and
150 ppm. If desired, an antibiotic can be included even if the
sugar concentration is relatively high. Alternatively, other
additives with anti-microbial of preservative properties may be
used. Preferably the antimicrobial additive(s) are food-grade.
[0177] A relatively high concentration solution can be obtained by
limiting the amount of water added to the carbohydrate-containing
material with the enzyme. The concentration can be controlled,
e.g., by controlling how much saccharification takes place. For
example, concentration can be increased by adding more
carbohydrate-containing material to the solution. In order to keep
the sugar that is being produced in solution, a surfactant can be
added, e.g., one of those discussed above. Solubility can also be
increased by increasing the temperature of the solution. For
example, the solution can be maintained at a temperature of
40-50.degree. C., 60-80.degree. C., or even higher.
Saccharifying Agents
[0178] Suitable cellulolytic enzymes include cellulases from
species in the genera Bacillus, Coprinus, Myceliophthora,
Cephalosporium, Scytalidium, Penicillium, Aspergillus, Pseudomonas,
Humicola, Fusarium, Thielavia, Acremonium, Chrysosporium and
Trichoderma, especially those produced by a strain selected from
the species Aspergillus (see, e.g., EP Pub. No. 0 458 162),
Humicola insolens (reclassified as Scytalidium thermophilum, see,
e.g., U.S. Pat. No. 4,435,307), Coprinus cinereus, Fusarium
oxysporum, Myceliophthora thermophila, Meripilus giganteus,
Thielavia terrestris, Acremonium sp. (including, but not limited
to, A. persicinum, A. acremonium, A. brachypenium, A.
dichromosporum, A. obclavatum, A. pinkertoniae, A. roseogriseum, A.
incoloratum, and A. furatum). Preferred strains include Humicola
insolens DSM 1800, Fusarium oxysporum DSM 2672, Myceliophthora
thermophila CBS 117.65, Cephalosporium sp. RYM-202, Acremonium sp.
CBS 478.94, Acremonium sp. CBS 265.95, Acremonium persicinum CBS
169.65, Acremonium acremonium AHU 9519, Cephalosporium sp. CBS
535.71, Acremonium brachypenium CBS 866.73, Acremonium
dichromosporum CBS 683.73, Acremonium obclavatum CBS 311.74,
Acremonium pinkertoniae CBS 157.70, Acremonium roseogriseum CBS
134.56, Acremonium incoloratum CBS 146.62, and Acremonium furatum
CBS 299.70H. Cellulolytic enzymes may also be obtained from
Chrysosporium, preferably a strain of Chrysosporium lucknowense.
Additional strains that can be used include, but are not limited
to, Trichoderma (particularly T. viride, T. reesei, and T.
koningii), alkalophilic Bacillus (see, for example, U.S. Pat. No.
3,844,890 and EP Pub. No. 0 458 162), and Streptomyces (see, e.g.,
EP Pub. No. 0 458 162).
[0179] In addition to or in combination to enzymes, acids, bases
and other chemicals (e.g., oxidants) can be utilized to saccharify
lignocellulosic and cellulosic materials. These can be used in any
combination or sequence (e.g., before, after and/or during addition
of an enzyme). For example, strong mineral acids can be utilized
(e.g. HCl, H.sub.2SO.sub.4, H.sub.3PO.sub.4) and strong bases
(e.g., NaOH, KOH).
Sugars
[0180] In the processes described herein, for example, after
saccharification, sugars (e.g., glucose and xylose) can be isolated
and/or purified. For example, sugars can be isolated and/or
purified by precipitation, crystallization, chromatography (e.g.,
simulated moving bed chromatography, high pressure chromatography),
electrodialysis, centrifugation, extraction, any other isolation
method known in the art, and combinations thereof.
Hydrogenation and Other Chemical Transformations
[0181] The processes described herein can include hydrogenation.
For example, glucose and xylose can be hydrogenated to sorbitol and
xylitol respectively. Hydrogenation can be accomplished by use of a
catalyst (e.g., Pt/gamma-Al.sub.2O.sub.3, Ru/C, Raney Nickel, or
other catalysts know in the art) in combination with thunder high
pressure (e.g., 10 to 12000 psi). Other types of chemical
transformation of the products from the processes described herein
can be used, for example, production of organic sugar derived
products such (e.g., furfural and furfural-derived products).
Chemical transformations of sugar derived products are described in
U.S. Ser. No. 13/934,704 filed Jul. 3, 2013, the entire disclosure
of which is incorporated herein by reference in its entirety.
Fermentation
[0182] Yeast and Zymomonas bacteria, for example, can be used for
fermentation or conversion of sugar(s) to alcohol(s). Other
microorganisms are discussed below. The optimum pH for
fermentations is about pH 4 to 7. For example, the optimum pH for
yeast is from about pH 4 to 5, while the optimum pH for Zymomonas
is from about pH 5 to 6. Typical fermentation times are about 24 to
168 hours (e.g., 24 to 96 hrs) with temperatures in the range of
20.degree. C. to 40.degree. C. (e.g., 26.degree. C. to 40.degree.
C.), however, thermophilic microorganisms prefer higher
temperatures.
[0183] In some embodiments, e.g., when anaerobic organisms are
used, at least a portion of the fermentation is conducted in the
absence of oxygen, e.g., under a blanket of an inert gas such as
N.sub.2, Ar, He, CO.sub.2 or mixtures thereof. Additionally, the
mixture may have a constant purge of an inert gas flowing through
the tank during part of or all of the fermentation. In some cases,
anaerobic condition, can be achieved or maintained by carbon
dioxide production during the fermentation and no additional inert
gas is needed.
[0184] In some embodiments, all or a portion of the fermentation
process can be interrupted before the low molecular weight sugar is
completely converted to a product (e.g., ethanol). The intermediate
fermentation products include sugar and carbohydrates in high
concentrations. The sugars and carbohydrates can be isolated via
any means known in the art. These intermediate fermentation
products can be used in preparation of food for human or animal
consumption. Additionally or alternatively, the intermediate
fermentation products can be ground to a fine particle size in a
stainless-steel laboratory mill to produce a flour-like substance.
Jet mixing may be used during fermentation, and in some cases
saccharification and fermentation are performed in the same
tank.
[0185] Nutrients for the microorganisms may be added during
saccharification and/or fermentation, for example, the food-based
nutrient packages described in U.S. Patent Pub. 2012/0052536, filed
Jul. 15, 2011, the complete disclosure of which is incorporated
herein by reference.
[0186] "Fermentation" includes the methods and products that are
disclosed in applications Nos. PCT/US2012/71093 published Jun. 27,
2013, PCT/US2012/71907 published Jun. 27, 2012, and
PCT/US2012/71083 published Jun. 27, 2012 the contents of which are
incorporated by reference herein in their entirety.
[0187] Mobile fermenters can be utilized, as described in
International App. No. PCT/US2007/074028 (which was filed Jul. 20,
2007, was published in English as WO 2008/011598 and designated the
United States) and has a U.S. Pat. No. 8,318,453, the contents of
which are incorporated herein in its entirety. Similarly, the
saccharification equipment can be mobile. Further, saccharification
and/or fermentation may be performed in part or entirely during
transit.
Fermentation Agents
[0188] The microorganism(s) used in fermentation can be
naturally-occurring microorganisms and/or engineered
microorganisms. For example, the microorganism can be a bacterium
(including, but not limited to, e.g., a cellulolytic bacterium), a
fungus, (including, but not limited to, e.g., a yeast), a plant, a
protist, e.g., a protozoa or a fungus-like protest (including, but
not limited to, e.g., a slime mold), or an alga. When the organisms
are compatible, mixtures of organisms can be utilized.
[0189] Suitable fermenting microorganisms have the ability to
convert carbohydrates, such as glucose, fructose, xylose,
arabinose, mannose, galactose, oligosaccharides or polysaccharides
into fermentation products. Fermenting microorganisms include
strains of the genus Saccharomyces spp. (including, but not limited
to, S. cerevisiae (baker's yeast), S. distaticus, S. uvarum), the
genus Kluyveromyces, (including, but not limited to, K. marxianus,
K. fragilis), the genus Candida (including, but not limited to, C.
pseudotropicalis, and C. brassicae), Pichia stipitis (a relative of
Candida shehatae), the genus Clavispora (including, but not limited
to, C. lusitaniae and C. opuntiae), the genus Pachysolen
(including, but not limited to, P. tannophilus), the genus
Bretannomyces (including, but not limited to, e.g., B. clausenii
(Philippidis, G. P., 1996, Cellulose bioconversion technology, in
Handbook on Bioethanol: Production and Utilization, Wyman, C. E.,
ed., Taylor & Francis, Washington, D.C., 179-212)). Other
suitable microorganisms include, for example, Zymomonas mobilis,
Clostridium spp. (including, but not limited to, C. thermocellum
(Philippidis, 1996, supra), C. saccharobutylacetonicum, C.
tyrobutyricum C. saccharobutylicum, C. Puniceum, C. beijernckii,
and C. acetobutylicum), Moniliella spp. (including but not limited
to M. pollinis, M. tomentosa, M. madida, M. nigrescens, M.
oedocephali, M. megachiliensis), Yarrowia lipolytica, Aureobasidium
sp., Trichosporonoides sp., Trigonopsis variabilis, Trichosporon
sp., Moniliellaacetoabutans sp., Typhula variabilis, Candida
magnoliae, Ustilaginomycetes sp., Pseudozyma tsukubaensis, yeast
species of genera Zygosaccharomyces, Debaryomyces, Hansenula and
Pichia, and fungi of the dematioid genus Torula (e.g., T.
corallina).
[0190] Many such microbial strains are publicly available, either
commercially or through depositories such as the ATCC (American
Type Culture Collection, Manassas, Va., USA), the NRRL
(Agricultural Research Service Culture Collection, Peoria, Ill.,
USA), or the DSMZ (Deutsche Sammlung von Mikroorganismen and
Zellkulturen GmbH, Braunschweig, Germany), to name a few.
[0191] Commercially available yeasts include, for example, RED
STAR.RTM./Lesaffre Ethanol Red (available from Red Star/Lesaffre,
USA), FALI.RTM. (available from Fleischmann's Yeast, a division of
Burns Philip Food Inc., USA), SUPERSTART.RTM. (Lallemand Biofuels
and Distilled Spirits, Canada), EAGLE C6 FUEL.TM. or C6 FUEL.TM.
(available from Lallemand Biofuels and Distilled Spirits, Canada),
(GERT STRAND.RTM. (available from Gert Strand AB, Sweden), and
FERMOL.RTM. (available from DSM Specialties).
Distillation
[0192] After fermentation, the resulting fluids can be distilled
using, for example, a "beer column" to separate ethanol and other
alcohols from the majority of water and residual solids. The vapor
exiting the beer column can be, e.g., 35% by weight ethanol and can
be fed to a rectification column. A mixture of nearly azeotropic
(92.5%) ethanol and water from the rectification column can be
purified to pure (99.5%) ethanol using vapor-phase molecular
sieves. The beer column bottoms can be sent to the first effect of
a three-effect evaporator. The rectification column reflux
condenser can provide heat for this first effect. After the first
effect, solids can be separated using a centrifuge and dried in a
rotary dryer. A portion (25%) of the centrifuge effluent can be
recycled to fermentation and the rest sent to the second and third
evaporator effects. Most of the evaporator condensate can be
returned to the process as fairly clean condensate with a small
portion split off to waste water treatment to prevent build-up of
low-boiling compounds.
Hydrocarbon-Containing Materials
[0193] In other embodiments utilizing the methods and systems
described herein, hydrocarbon-containing materials can be
processed. Any process described herein can be used to treat any
hydrocarbon-containing material herein described.
"Hydrocarbon-containing materials," as used herein, is meant to
include oil sands, oil shale, tar sands, coal dust, coal slurry,
bitumen, various types of coal, and other naturally-occurring and
synthetic materials that include both hydrocarbon components and
solid matter. The solid matter can include rock, sand, clay, stone,
silt, drilling slurry, or other solid organic and/or inorganic
matter. The term can also include waste products such as drilling
waste and by-products, refining waste and by-products, or other
waste products containing hydrocarbon components, such as asphalt
shingling and covering, asphalt pavement, etc.
[0194] In yet other embodiments utilizing the methods and systems
described herein, wood and wood containing produces can be
processed. For example, lumber products can be processed, e.g.
boards, sheets, laminates, beams, particle boards, composites,
rough cut wood, soft wood and hard wood. In addition, cut trees,
bushes, wood chips, saw dust, roots, bark, stumps, decomposed wood
and other wood containing biomass material can be processed.
Conveying Systems
[0195] Various conveying systems, including and in addition to the
conveying systems already discussed herein can be used to convey
the biomass material, for example, as discussed, to a vault, and
under an electron beam in a vault. Exemplary conveyors are belt
conveyors, pneumatic conveyors, screw conveyors, carts, trains,
trains or carts on rails, elevators, front loaders, backhoes,
cranes, various scrapers and shovels, trucks, and throwing devices
can be used.
[0196] Optionally, including and in addition to the conveying
systems described herein, one or more other conveying systems can
be enclosed. When using an enclosure, the enclosed conveyor can
also be purged with an inert gas so as to maintain an atmosphere at
a reduced oxygen level. Keeping oxygen levels low avoids the
formation of ozone which in some instances is undesirable due to
its reactive and toxic nature. For example, the oxygen can be less
than about 20% (e.g., less than about 10%, less than about 1%, less
than about 0.1%, less than about 0.01%, or even less than about
0.001% oxygen). Purging can be done with an inert gas including,
but not limited to, nitrogen, argon, helium or carbon dioxide. This
can be supplied, for example, from a boil off of a liquid source
(e.g., liquid nitrogen or helium), generated or separated from air
in situ, or supplied from tanks. The inert gas can be recirculated
and any residual oxygen can be removed using a catalyst, such as a
copper catalyst bed. Alternatively, combinations of purging,
recirculating and oxygen removal can be done to keep the oxygen
levels low.
[0197] The enclosed conveyor can also be purged with a reactive gas
that can react with the biomass. This can be done before, during or
after the irradiation process. The reactive gas can be, but is not
limited to, nitrous oxide, ammonia, oxygen, ozone, hydrocarbons,
aromatic compounds, amides, peroxides, azides, halides, oxyhalides,
phosphides, phosphines, arsines, sulfides, thiols, boranes and/or
hydrides. The reactive gas can be activated in the enclosure, e.g.,
by irradiation (e.g., electron beam, UV irradiation, microwave
irradiation, heating, IR radiation), so that it reacts with the
biomass. The biomass itself can be activated, for example, by
irradiation. Preferably the biomass is activated by the electron
beam, to produce radicals which then react with the activated or
unactivated reactive gas, e.g., by radical coupling or quenching.
Purging gases supplied to an enclosed conveyor can also be cooled,
for example, below about 25.degree. C., below about 0.degree. C.,
below about -40.degree. C., below about -80.degree. C., below about
-120.degree. C. For example, the gas can be boiled off from a
compressed gas such as liquid nitrogen or sublimed from solid
carbon dioxide. As an alternative example, the gas can be cooled by
a chiller or part of or the entire conveyor can be cooled.
Other Embodiments
[0198] Any material, processes or processed materials discussed
herein can be used to make products and/or intermediates such as
composites, fillers, binders, plastic additives, adsorbents and
controlled release agents. The methods can include densification,
for example, by applying pressure and heat to the materials. For
example, composites can be made by combining fibrous materials with
a resin or polymer. For example, radiation cross-linkable resin,
e.g., a thermoplastic resin can be combined with a fibrous material
to provide a fibrous material/cross-linkable resin combination.
Such materials can be, for example, useful as building materials,
protective sheets, containers and other structural materials (e.g.,
molded and/or extruded products). Absorbents can be, for example,
in the form of pellets, chips, fibers and/or sheets. Adsorbents can
be used, for example, as pet bedding, packaging material or in
pollution control systems. Controlled release matrices can also be
the form of, for example, pellets, chips, fibers and or sheets. The
controlled release matrices can, for example, be used to release
drugs, biocides, fragrances. For example, composites, absorbents
and control release agents and their uses are described in
International Application No. PCT/US2006/010648, filed Mar. 23,
2006, and U.S. Pat. No. 8,074,910 filed Nov. 22, 2011, the entire
disclosures of which are herein incorporated by reference.
[0199] In some instances the biomass material is treated at a first
level to reduce recalcitrance, e.g., utilizing accelerated
electrons, to selectively release one or more sugars (e.g.,
xylose). The biomass can then be treated to a second level to
release one or more other sugars (e.g., glucose). Optionally the
biomass can be dried between treatments. The treatments can include
applying chemical and biochemical treatments to release the sugars.
For example, a biomass material can be treated to a level of less
than about 20 Mrad (e.g., less than about 15 Mrad, less than about
10 Mrad, less than about 5 Mrad, less than about 2 Mrad) and then
treated with a solution of sulfuric acid, containing less than 10%
sulfuric acid (e.g., less than about 9%, less than about 8%, less
than about 7%, less than about 6%, less than about 5%, less than
about 4%, less than about 3%, less than about 2%, less than about
1%, less than about 0.75%, less than about 0.50%, less than about
0.25%) to release xylose. Xylose, for example, that is released
into solution, can be separated from solids and optionally the
solids washed with a solvent/solution (e.g., with water and/or
acidified water). Optionally, the solids can be dried, for example,
in air and/or under vacuum optionally with heating (e.g., below
about 150 deg C., below about 120 deg C.) to a water content below
about 25 wt % (below about 20 wt. %, below about 15 wt. %, below
about 10 wt. %, below about 5 wt. %). The solids can then be
treated with a level of less than about 30 Mrad (e.g., less than
about 25 Mrad, less than about 20 Mrad, less than about 15 Mrad,
less than about 10 Mrad, less than about 5 Mrad, less than about 1
Mrad or even not at all) and then treated with an enzyme (e.g., a
cellulase) to release glucose. The glucose (e.g., glucose in
solution) can be separated from the remaining solids. The solids
can then be further processed, for example, utilized to make energy
or other products (e.g., lignin derived products).
Flavors, Fragrances and Colorants
[0200] Any of the products and/or intermediates described herein,
for example, produced by the processes, systems and/or equipment
described herein, can be combined with flavors, fragrances,
colorants and/or mixtures of these. For example, any one or more of
(optionally along with flavors, fragrances and/or colorants)
sugars, organic acids, fuels, polyols, such as sugar alcohols,
biomass, fibers and composites can be combined with (e.g.,
formulated, mixed or reacted) or used to make other products. For
example, one or more such product can be used to make soaps,
detergents, candies, drinks (e.g., cola, wine, beer, liquors such
as gin or vodka, sports drinks, coffees, teas), pharmaceuticals,
adhesives, sheets (e.g., woven, none woven, filters, tissues)
and/or composites (e.g., boards). For example, one or more such
product can be combined with herbs, flowers, petals, spices,
vitamins, potpourri, or candles. For example, the formulated, mixed
or reacted combinations can have flavors/fragrances of grapefruit,
orange, apple, raspberry, banana, lettuce, celery, cinnamon,
chocolate, vanilla, peppermint, mint, onion, garlic, pepper,
saffron, ginger, milk, wine, beer, tea, lean beef, fish, clams,
olive oil, coconut fat, pork fat, butter fat, beef bouillon,
legume, potatoes, marmalade, ham, coffee and cheeses.
[0201] Flavors, fragrances and colorants can be added in any
amount, such as between about 0.001 wt. % to about 30 wt. %, e.g.,
between about 0.01 to about 20, between about 0.05 to about 10, or
between about 0.1 wt. % to about 5 wt. %. These can be formulated,
mixed and or reacted (e.g., with any one of more product or
intermediate described herein) by any means and in any order or
sequence (e.g., agitated, mixed, emulsified, gelled, infused,
heated, sonicated, and/or suspended). Fillers, binders, emulsifier,
antioxidants can also be utilized, for example, protein gels,
starches and silica.
[0202] In one embodiment the flavors, fragrances and colorants can
be added to the biomass immediately after the biomass is irradiated
such that the reactive sites created by the irradiation may react
with reactive compatible sites of the flavors, fragrances, and
colorants.
[0203] The flavors, fragrances and colorants can be natural and/or
synthetic materials. These materials can be one or more of a
compound, a composition or mixtures of these (e.g., a formulated or
natural composition of several compounds). Optionally the flavors,
fragrances, antioxidants and colorants can be derived biologically,
for example, from a fermentation process (e.g., fermentation of
saccharified materials as described herein). Alternatively, or
additionally these flavors, fragrances and colorants can be
harvested from a whole organism (e.g., plant, fungus, animal,
bacteria or yeast) or a part of an organism. The organism can be
collected and or extracted to provide color, flavors, fragrances
and/or antioxidant by any means including utilizing the methods,
systems and equipment described herein, hot water extraction,
supercritical fluid extraction, chemical extraction (e.g., solvent
or reactive extraction including acids and bases), mechanical
extraction (e.g., pressing, comminuting, filtering), utilizing an
enzyme, utilizing a bacteria such as to break down a starting
material, and combinations of these methods. The compounds can be
derived by a chemical reaction, for example, the combination of a
sugar (e.g., as produced as described herein) with an amino acid
(Maillard reaction). The flavor, fragrance, antioxidant and/or
colorant can be an intermediate and or product produced by the
methods, equipment or systems described herein, for example, and
ester and a lignin derived product.
[0204] Some examples of flavor, fragrances or colorants are
polyphenols. Polyphenols are pigments responsible for the red,
purple and blue colorants of many fruits, vegetables, cereal
grains, and flowers. Polyphenols also can have antioxidant
properties and often have a bitter taste. The antioxidant
properties make these important preservatives. On class of
polyphenols are the flavonoids, such as Anthocyanidines,
flavanonols, flavan-3-ols, s, flavanones and flavanonols. Other
phenolic compounds that can be used include phenolic acids and
their esters, such as chlorogenic acid and polymeric tannins.
[0205] Among the colorants inorganic compounds, minerals or organic
compounds can be used, for example, titanium dioxide, zinc oxide,
aluminum oxide, cadmium yellow (E.g., CdS), cadmium orange (e.g.,
CdS with some Se), alizarin crimson (e.g., synthetic or
non-synthetic rose madder), ultramarine (e.g., synthetic
ultramarine, natural ultramarine, synthetic ultramarine violet),
cobalt blue, cobalt yellow, cobalt green, viridian (e.g., hydrated
chromium(III)oxide), chalcophylite, conichalcite, cornubite,
cornwallite and liroconite. Black pigments such as carbon black and
self-dispersed blacks may be used.
[0206] Some flavors and fragrances that can be utilized include
ACALEA TBHQ, ACET C-6, ALLYL AMYL GLYCOLATE, ALPHA TERPINEOL,
AMBRETTOLIDE, AMBRINOL 95, ANDRANE, APHERMATE, APPLELIDE,
BACDANOL.RTM., BERGAMAL, BETA IONONE EPDXIDE, BETA NAPHTHYL
ISO-BUTYL ETHER, BICYCLONONALACTONE, BORNAFIX.RTM., CANTHOXAL,
CASHMERAN.RTM., CASHMERAN.RTM. VELVET, CASSIFFIX.RTM., CEDRAFIX,
CEDRAMBER.RTM., CEDRYL ACETATE, CELESTOLIDE, CINNAMALVA, CITRAL
DIMETHYL ACETATE, CITROLATE.TM., CITRONELLOL 700, CITRONELLOL 950,
CITRONELLOL COEUR, CITRONELLYL ACETATE, CITRONELLYL ACETATE PURE,
CITRONELLYL FORMATE, CLARYCET, CLONAL, CONIFERAN, CONIFERAN PURE,
CORTEX ALDEHYDE 50% PEOMOSA, CYCLABUTE, CYCLACET.RTM.,
CYCLAPROP.RTM., CYCLEMAX.TM., CYCLOHEXYL ETHYL ACETATE, DAMASCOL,
DELTA DAMASCONE, DIHYDRO CYCLACET, DIHYDRO MYRCENOL, DIHYDRO
TERPINEOL, DIHYDRO TERPINYL ACETATE, DIMETHYL CYCLORMOL, DIMETHYL
OCTANOL PQ, DIMYRCETOL, DIOLA, DIPENTENE, DULCINYL.RTM.
RECRYSTALLIZED, ETHYL-3-PHENYL GLYCIDATE, FLEURAMONE, FLEURANIL,
FLORAL SUPER, FLORALOZONE, FLORIFFOL, FRAISTONE, FRUCTONE,
GALAXOLIDE.RTM. 50, GALAXOLIDE.RTM. 50 BB, GALAXOLIDE.RTM. 50 IPM,
GALAXOLIDE.RTM. UNDILUTED, GALBASCONE, GERALDEHYDE, GERANIOL 5020,
GERANIOL 600 TYPE, GERANIOL 950, GERANIOL 980 (PURE), GERANIOL CFT
COEUR, GERANIOL COEUR, GERANYL ACETATE COEUR, GERANYL ACETATE,
PURE, GERANYL FORMATE, GRISALVA, GUAIYL ACETATE, HELIONAL.TM.,
HERBAC, HERBALIME.TM., HEXADECANOLIDE, HEXALON, HEXENYL SALICYLATE
CIS 3-, HYACINTH BODY, HYACINTH BODY NO. 3, HYDRATROPIC
ALDEHYDE.DMA, HYDROXYOL, INDOLAROME, INTRELEVEN ALDEHYDE,
INTRELEVEN ALDEHYDE SPECIAL, IONONE ALPHA, IONONE BETA, ISO CYCLO
CITRAL, ISO CYCLO GERANIOL, ISO E SUPER.RTM., ISOBUTYL QUINOLINE,
JASMAL, JESSEMAL.RTM., KHARISMAL.RTM., KHARISMAL.RTM. SUPER,
KHUSINIL, KOAVONE.RTM., KOHINOOL.RTM., LIFFAROME.TM., LIMOXAL,
LINDENOL.TM., LYRAL.RTM., LYRAME SUPER, MANDARIN ALD 10% TRI ETH,
CITR, MARITIMA, MCK CHINESE, MEIJIFF.TM., MELAFLEUR, MELOZONE,
METHYL ANTHRANILATE, METHYL IONONE ALPHA EXTRA, METHYL IONONE GAMMA
A, METHYL IONONE GAMMA COEUR, METHYL IONONE GAMMA PURE, METHYL
LAVENDER KETONE, MONTAVERDI.RTM., MUGUESIA, MUGUET ALDEHYDE 50,
MUSK Z4, MYRAC ALDEHYDE, MYRCENYL ACETATE, NECTARATE.TM., NEROL
900, NERYL ACETATE, OCIMENE, OCTACETAL, ORANGE FLOWER ETHER,
ORIVONE, ORRINIFF 25%, OXASPIRANE, OZOFLEUR, PAMPLEFLEUR.RTM.,
PEOMOSA, PHENOXANOL.RTM., PICONIA, PRECYCLEMONE B, PRENYL ACETATE,
PRISMANTOL, RESEDA BODY, ROSALVA, ROSAMUSK, SANJINOL,
SANTALIFF.TM., SYVERTAL, TERPINEOL, TERPINOLENE 20, TERPINOLENE 90
PQ, TERPINOLENE RECT., TERPINYL ACETATE, TERPINYL ACETATE JAX,
TETRAHYDRO, MUGUOL.RTM., TETRAHYDRO MYRCENOL, TETRAMERAN,
TIMBERSILK.TM., TOBACAROL, TRIMOFIX.RTM. 0 TT, TRIPLAL.RTM.,
TRISAMBER.RTM., VANORIS, VERDOX.TM., VERDOX.TM. HC, VERTENEX.RTM.,
VERTENEX.RTM. HC, VERTOFIX.RTM. COEUR, VERTOLIFF, VERTOLIFF ISO,
VIOLIFF, VIVALDIE, ZENOLIDE, ABS INDIA 75 PCT MIGLYOL, ABS MOROCCO
50 PCT DPG, ABS MOROCCO 50 PCT TEC, ABSOLUTE FRENCH, ABSOLUTE
INDIA, ABSOLUTE MD 50 PCT BB, ABSOLUTE MOROCCO, CONCENTRATE PG,
TINCTURE 20 PCT, AMBERGRIS, AMBRETTE ABSOLUTE, AMBRETTE SEED OIL,
ARMOISE OIL 70 PCT THUYONE, BASIL ABSOLUTE GRAND VERT, BASIL GRAND
VERT ABS MD, BASIL OIL GRAND VERT, BASIL OIL VERVEINA, BASIL OIL
VIETNAM, BAY OIL TERPENELESS, BEESWAX ABS N G, BEESWAX ABSOLUTE,
BENZOIN RESINOID SIAM, BENZOIN RESINOID SIAM 50 PCT DPG, BENZOIN
RESINOID SIAM 50 PCT PG, BENZOIN RESINOID SIAM 70.5 PCT TEC,
BLACKCURRANT BUD ABS 65 PCT PG, BLACKCURRANT BUD ABS MD 37 PCT TEC,
BLACKCURRANT BUD ABS MIGLYOL, BLACKCURRANT BUD ABSOLUTE BURGUNDY,
BOIS DE ROSE OIL, BRAN ABSOLUTE, BRAN RESINOID, BROOM ABSOLUTE
ITALY, CARDAMOM GUATEMALA CO2 EXTRACT, CARDAMOM OIL GUATEMALA,
CARDAMOM OIL INDIA, CARROT HEART, CASSIE ABSOLUTE EGYPT, CASSIE
ABSOLUTE MD 50 PCT IPM, CASTOREUM ABS 90 PCT TEC, CASTOREUM ABS C
50 PCT MIGLYOL, CASTOREUM ABSOLUTE, CASTOREUM RESINOID, CASTOREUM
RESINOID 50 PCT DPG, CEDROL CEDRENE, CEDRUS ATLANTICA OIL REDIST,
CHAMOMILE OIL ROMAN, CHAMOMILE OIL WILD, CHAMOMILE OIL WILD LOW
LIMONENE, CINNAMON BARK OIL CEYLAN, CISTE ABSOLUTE, CISTE ABSOLUTE
COLORLESS, CITRONELLA OIL ASIA IRON FREE, CIVET ABS 75 PCT PG,
CIVET ABSOLUTE, CIVET TINCTURE 10 PCT, CLARY SAGE ABS FRENCH DECOL,
CLARY SAGE ABSOLUTE FRENCH, CLARY SAGE C'LESS 50 PCT PG, CLARY SAGE
OIL FRENCH, COPAIBA BALSAM, COPAIBA BALSAM OIL, CORIANDER SEED OIL,
CYPRESS OIL, CYPRESS OIL ORGANIC, DAVANA OIL, GALBANOL, GALBANUM
ABSOLUTE COLORLESS, GALBANUM OIL, GALBANUM RESINOID, GALBANUM
RESINOID 50 PCT DPG, GALBANUM RESINOID HERCOLYN BHT, GALBANUM
RESINOID TEC BHT, GENTIANE ABSOLUTE MD 20 PCT BB, GENTIANE
CONCRETE, GERANIUM ABS EGYPT MD, GERANIUM ABSOLUTE EGYPT, GERANIUM
OIL CHINA, GERANIUM OIL EGYPT, GINGER OIL 624, GINGER OIL RECTIFIED
SOLUBLE, GUAIACWOOD HEART, HAY ABS MD 50 PCT BB, HAY ABSOLUTE, HAY
ABSOLUTE MD 50 PCT TEC, HEALINGWOOD, HYSSOP OIL ORGANIC, IMMORTELLE
ABS YUGO MD 50 PCT TEC, IMMORTELLE ABSOLUTE SPAIN, IMMORTELLE
ABSOLUTE YUGO, JASMIN ABS INDIA MD, JASMIN ABSOLUTE EGYPT, JASMIN
ABSOLUTE INDIA, ASMIN ABSOLUTE MOROCCO, JASMIN ABSOLUTE SAMBAC,
JONQUILLE ABS MD 20 PCT BB, JONQUILLE ABSOLUTE France, JUNIPER
BERRY OIL FLG, JUNIPER BERRY OIL RECTIFIED SOLUBLE, LABDANUM
RESINOID 50 PCT TEC, LABDANUM RESINOID BB, LABDANUM RESINOID MD,
LABDANUM RESINOID MD 50 PCT BB, LAVANDIN ABSOLUTE H, LAVANDIN
ABSOLUTE MD, LAVANDIN OIL ABRIAL ORGANIC, LAVANDIN OIL GROSSO
ORGANIC, LAVANDIN OIL SUPER, LAVENDER ABSOLUTE H, LAVENDER ABSOLUTE
MD, LAVENDER OIL COUMARIN FREE, LAVENDER OIL COUMARIN FREE ORGANIC,
LAVENDER OIL MAILLETTE ORGANIC, LAVENDER OIL MT, MACE ABSOLUTE BB,
MAGNOLIA FLOWER OIL LOW METHYL EUGENOL, MAGNOLIA FLOWER OIL,
MAGNOLIA FLOWER OIL MD, MAGNOLIA LEAF OIL, MANDARIN OIL MD,
MANDARIN OIL MD BHT, MATE ABSOLUTE BB, MOSS TREE ABSOLUTE MD TEX
IFRA 43, MOSS-OAK ABS MD TEC IFRA 43, MOSS-OAK ABSOLUTE IFRA 43,
MOSS-TREE ABSOLUTE MD IPM IFRA 43, MYRRH RESINOID BB, MYRRH
RESINOID MD, MYRRH RESINOID TEC, MYRTLE OIL IRON FREE, MYRTLE OIL
TUNISIA RECTIFIED, NARCISSE ABS MD 20 PCT BB, NARCISSE ABSOLUTE
FRENCH, NEROLI OIL TUNISIA, NUTMEG OIL TERPENELESS, OEILLET
ABSOLUTE, OLIBANUM RESINOID, OLIBANUM RESINOID BB, OLIBANUM
RESINOID DPG, OLIBANUM RESINOID EXTRA 50 PCT DPG, OLIBANUM RESINOID
MD, OLIBANUM RESINOID MD 50 PCT DPG, OLIBANUM RESINOID TEC,
OPOPONAX RESINOID TEC, ORANGE BIGARADE OIL MD BHT, ORANGE BIGARADE
OIL MD SCFC, ORANGE FLOWER ABSOLUTE TUNISIA, ORANGE FLOWER WATER
ABSOLUTE TUNISIA, ORANGE LEAF ABSOLUTE, ORANGE LEAF WATER ABSOLUTE
TUNISIA, ORRIS ABSOLUTE ITALY, ORRIS CONCRETE 15 PCT IRONE, ORRIS
CONCRETE 8 PCT IRONE, ORRIS NATURAL 15 PCT IRONE 4095C, ORRIS
NATURAL 8 PCT IRONE 2942C, ORRIS RESINOID, OSMANTHUS ABSOLUTE,
OSMANTHUS ABSOLUTE MD 50 PCT BB, PATCHOULI HEART No 3, PATCHOULI
OIL INDONESIA, PATCHOULI OIL INDONESIA IRON FREE, PATCHOULI OIL
INDONESIA MD, PATCHOULI OIL REDIST, PENNYROYAL HEART, PEPPERMINT
ABSOLUTE MD, PETITGRAIN BIGARADE OIL TUNISIA, PETITGRAIN CITRONNIER
OIL, PETITGRAIN OIL PARAGUAY TERPENELESS, PETITGRAIN OIL
TERPENELESS STAB, PIMENTO BERRY OIL, PIMENTO LEAF OIL, RHODINOL EX
GERANIUM CHINA, ROSE ABS BULGARIAN LOW METHYL EUGENOL, ROSE ABS
MOROCCO LOW METHYL EUGENOL, ROSE ABS TURKISH LOW METHYL EUGENOL,
ROSE ABSOLUTE, ROSE ABSOLUTE BULGARIAN, ROSE ABSOLUTE DAMASCENA,
ROSE ABSOLUTE MD, ROSE ABSOLUTE MOROCCO, ROSE ABSOLUTE TURKISH,
ROSE OIL BULGARIAN, ROSE OIL DAMASCENA LOW METHYL EUGENOL, ROSE OIL
TURKISH, ROSEMARY OIL CAMPHOR ORGANIC, ROSEMARY OIL TUNISIA,
SANDALWOOD OIL INDIA, SANDALWOOD OIL INDIA RECTIFIED, SANTALOL,
SCHINUS MOLLE OIL, ST JOHN BREAD TINCTURE 10 PCT, STYRAX RESINOID,
STYRAX RESINOID, TAGETE OIL, TEA TREE HEART, TONKA BEAN ABS 50 PCT
SOLVENTS, TONKA BEAN ABSOLUTE, TUBEROSE ABSOLUTE INDIA, VETIVER
HEART EXTRA, VETIVER OIL HAITI, VETIVER OIL HAITI MD, VETIVER OIL
JAVA, VETIVER OIL JAVA MD, VIOLET LEAF ABSOLUTE EGYPT, VIOLET LEAF
ABSOLUTE EGYPT DECOL, VIOLET LEAF ABSOLUTE FRENCH, VIOLET LEAF
ABSOLUTE MD 50 PCT BB, WORMWOOD OIL TERPENELESS, YLANG EXTRA OIL,
YLANG III OIL and combinations of these.
[0207] The colorants can be among those listed in the Colour Index
International by the Society of Dyers and Colourists. Colorants
include dyes and pigments and include those commonly used for
coloring textiles, paints, inks and inkjet inks. Some colorants
that can be utilized include carotenoids, arylide yellows,
diarylide yellows, -naphthols, naphthols, benzimidazolones, disazo
condensation pigments, pyrazolones, nickel azo yellow,
phthalocyanines, quinacridones, perylenes and perinones,
isoindolinone and isoindoline pigments, triarylcarbonium pigments,
diketopyrrolo-pyrrole pigments, thioindigoids. Cartenoids include,
e.g., alpha-carotene, beta-carotene, gamma-carotene, lycopene,
lutein and astaxanthin Annatto extract, Dehydrated beets (beet
powder), Canthaxanthin, Caramel, .beta.-Apo-8'-carotenal, Cochineal
extract, Carmine, Sodium copper chlorophyllin, Toasted partially
defatted cooked cottonseed flour, Ferrous gluconate, Ferrous
lactate, Grape color extract, Grape skin extract (enocianina),
Carrot oil, Paprika, Paprika oleoresin, Mica-based pearlescent
pigments, Riboflavin, Saffron, Titanium dioxide, Tomato lycopene
extract; tomato lycopene concentrate, Turmeric, Turmeric oleoresin,
FD&C Blue No. 1, FD&C Blue No. 2, FD&C Green No. 3,
Orange B, Citrus Red No. 2, FD&C Red No. 3, FD&C Red No.
40, FD&C Yellow No. 5, FD&C Yellow No. 6, Alumina (dried
aluminum hydroxide), Calcium carbonate, Potassium sodium copper
chloro