U.S. patent application number 13/252501 was filed with the patent office on 2012-02-02 for method and system for the large scale collection, preparation, handling and refining of ligno-cellulosic biomass.
This patent application is currently assigned to IOGEN ENERGY CORPORATION. Invention is credited to Patrick Foody, SR..
Application Number | 20120023814 13/252501 |
Document ID | / |
Family ID | 39051282 |
Filed Date | 2012-02-02 |
United States Patent
Application |
20120023814 |
Kind Code |
A1 |
Foody, SR.; Patrick |
February 2, 2012 |
METHOD AND SYSTEM FOR THE LARGE SCALE COLLECTION, PREPARATION,
HANDLING AND REFINING OF LIGNO-CELLULOSIC BIOMASS
Abstract
A system for collecting ligno-cellulosic biomass over a large
area to enable the commercial refining of biomass from 2,500 to in
excess of 50,000 tons of biomass per day to produce ethanol or
other products. The biomass is collected at a series of collection
points and then transported through a network of conduit "loops"
interconnecting each of the collection points and the central
refining plant. The water used to transport the biomass, as a
slurry, is recovered and sequentially recycled in the same pipeline
system to push the biomass slurry around the system in a
"loop".
Inventors: |
Foody, SR.; Patrick;
(Hudson, CA) |
Assignee: |
IOGEN ENERGY CORPORATION
Ottawa
CA
|
Family ID: |
39051282 |
Appl. No.: |
13/252501 |
Filed: |
October 4, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11769850 |
Jun 28, 2007 |
8057635 |
|
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13252501 |
|
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60836737 |
Aug 10, 2006 |
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Current U.S.
Class: |
44/605 |
Current CPC
Class: |
Y02E 50/30 20130101;
Y02E 50/10 20130101; C12M 47/02 20130101; C12M 47/14 20130101; Y02E
50/16 20130101; C12P 7/10 20130101 |
Class at
Publication: |
44/605 |
International
Class: |
C10L 5/00 20060101
C10L005/00 |
Claims
1.-11. (canceled)
12. A method for collecting and refining biomass, comprising:
collecting biomass at a plurality of collection points which are
connected with a biomass refining plant by at least one conduit
loop; introducing the biomass into at least one conduit loop to
form a slurry of biomass and liquid; transporting the slurry of
biomass and liquid through at least one conduit loop to the
refining plant where the biomass is subjected to cooking; and
removing water from the slurry and continuously reusing the water
to transport additional biomass.
13. The method according to claim 12, further comprising
pretreating the slurry of biomass and water in the network to a pH
favorable for a later disintegration of lignin and cellulose bonds
at the refining plant.
14. The method according to claim 12, further comprising the steps
of joining streams of slurry transported from two or more of the
plurality of collection points into a single slurry stream directed
to the refining plant and splitting the water removed from the
slurry coming from the refining plant for recirculation.
15. A method according to claim 13 wherein the biomass is reduced
in size and the slurry is pH-adjusted for introduction into the
cooking phase.
16. The method according to claim 12, further comprising the step
of removing water to maintain a relatively constant amount of water
circulating in the system.
17. The method according to claim 12, comprising a plurality of
conduit loops connecting the collection points to the refining
plant.
18. A method according to claim 17, wherein each of the loops can
be operated independently.
19. A method according to claim 17, wherein the number of loops is
matched to the refining plant production capability.
Description
[0001] This application claims the benefit of priority of U.S.
patent application Ser. No. 11/769,850, filed Jun. 28, 2007, and
U.S. Provisional Application No. 60/836,737, filed Aug. 10, 2006,
which are both incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention is in the field of biomass collection and
preconditioning for subsequent refining into ethanol and other
products. Specifically, the invention is directed to the collection
of biomass over a large area so as to take advantage of economies
of scale. According to embodiments, the biomass may be
preconditioned to a selected pH, either in stockpiles, or at a
centrally located plant prior to downstream processing.
[0004] 2. Description of the Related Art
[0005] U.S. Pat. No. 4,461,648 to Patrick Foody, herein
incorporated by reference in its entirety, discloses technology in
which cellulose is made accessible for chemical reaction by a
process of steam explosion and chemical disintegration to break
down the bonds between the lignin and cellulose in the biomass.
During the 1970's, after the first "oil shock" occurred, the
inventor was conducting research on making low-grade fiber and wood
digestible to ruminant animals. He recognized that accessibility of
these materials to ruminant animal microflora and accessibility to
enzymes was in fact a very similar problem. Trials were conducted
using steam explosion to fractionate the fiber. As it turned out,
it was a much more difficult problem than simply "exploding" the
fiber to fractionate the internal bonds, and involved a very narrow
window across the time/temperature range at which the process could
be optimized. Nevertheless, the result of these efforts, disclosed
and claimed in U.S. Pat. No. 4,461,648 was a process that made the
cellulose completely accessible to enzymes. This was the first
breakthrough in the technology and arguably laid the foundation for
biomass refining, as the science is currently called.
[0006] However, one key barrier still remains to achieving real
economic competitiveness, that is, the problem of "scale." The
present invention, the inventor believes, will be the last piece in
the puzzle that will make biomass ethanol competitive with oil.
[0007] U.S. Pat. No. 5,916,780, to Brian Foody, et al., herein
incorporated by reference in its entirety, discloses technology for
pre-treating and transporting biomass, especially as it relates to
the production of ethanol.
[0008] Japanese Patent No. JP2002330644 proposes a system for
biomass collection. However this patent discloses a pneumatic
system and does not adequately address the implementation of a
large scale biomass collection and refining system.
[0009] Pipeline systems for moving woodchips are not uncommon, but
these are normally used on a point-to-point basis. Peter C. Flynn,
et al., Bioresource Technology, 96 (2005) 819-829 postulates a
biomass refining system wherein the water may be pumped back either
completely or in part to the beginning of the system. This requires
two pipelines, as noted by the author, and is not economically
viable.
[0010] In order to be viable, ethanol from biomass (also referred
to herein as cellulosic ethanol) must overcome advantages that
accrue to its industrial competitors, the grain ethanol and
petroleum industries. One of these advantages is that the road,
rail, pipeline and river infrastructure for transporting
conventional energy products is already in place.
[0011] Biomass by its nature is at a significant cost and handling
disadvantage as compared to these competitors. For example, grain,
which is free flowing, weighs 40 lbs to 50 lbs per cubic foot,
while biomass weighs 10 lbs per cubic foot in bales, and 5 lbs per
cubic foot loose. The largest grain ethanol plants being currently
built, without access to water or rail transportation, handle on
the order of 2,500 tons per day. At a "test weight" of 5 lbs per
cubic foot, the viability of a biomass refining system is largely
dictated by access to road systems. The differential in the volume
to be moved could challenge the capacity of most road systems. In
order to take advantage of the cheaper unit cost of biomass, it is
estimated that a system capable of processing significantly in
excess of 2,500 tons per day of biomass would be necessary for
cellulosic ethanol to compete with easily refined starch based
grain ethanol.
[0012] The oil industry, the other conventional competitor to
biomass refining, has the advantage of "scale" and well established
pipeline systems so that it can tolerate significantly higher raw
material costs.
[0013] It is estimated that a cellulosic ethanol system capable of
processing in excess of 10,000 tons per day of biomass would be
required to compete with oil.
[0014] Further technological and scientific advances in materials
handling and physical layouts are necessary to make ethanol from
biomass commercially competitive with oil, especially with regard
to the economies of scale.
[0015] An important object of this invention is to overcome the
difficulties and expenses that arise in connection with handling
large amounts of relatively light non-free flowing biomass. The
inventor herein has developed a continuous "loop" system for moving
a biomass slurry along the same pipeline as the transportation
water, as well as adding new biomass at more than one selected
point along the pipeline. According to embodiments of the present
invention, conventional delivery systems, except for local
pick-ups, can be avoided altogether, in favor of the centralized
and integrated network of loops described herein.
SUMMARY OF THE INVENTION
[0016] A biomass collection and refining system according to the
invention comprises a biomass refining plant, a plurality of
collection points and at least one conduit loop connecting the
collection points and the refining plant through a continuous
circulating arrangement, so that a slurry of water and biomass is
transported from the collection points to the refining plant and
the transportation water is recovered and reintroduced along with
recovered process water to the same conduit. "Conduit," as used
herein includes, without limitation, pipes, canals, or like
structures. Optionally, the system comprises a plurality of loops
connecting the collection points and the refining plant.
[0017] The method according to the invention involves collecting
biomass at a plurality of pick-up points (also referred to herein
as "collection points"). The biomass may arrive chopped, or some pH
conditioning may be done at the collection points (or elsewhere
along the transport path) for introduction into the cooking phase,
as desired. The biomass is introduced into the conduit loop to form
a slurry of biomass and liquid (such as, without limitation, a 5 wt
% solids mix in water) at one or more of the collection points and
is transported through at least one conduit loop connecting each of
the collection points on a particular "loop" with the central
refining plant where the biomass is subjected to cooking. Water is
removed from the slurry at the refining plant, using a separating
device, cane press, screw press, screens or the like apparatus, and
reused for continual transport of biomass through one or more
conduit loops.
BRIEF DESCRIPTION OF THE FIGURES
[0018] FIG. 1 depicts a single loop configuration showing the
general relationship of a centrally located refining plant, a
pipeline system leaving the plant, water being charged into the
pipeline system, introduction of biomass at one or several points
along the line, as well as the removal of the water for reuse. The
biomass then goes into the refining plant.
[0019] FIG. 1A is a detail of FIG. 1, depicting a typical water
removal system using a centrifuge. Alternatively, a cane press,
screw presses or the like water removal apparatus may be used.
[0020] FIG. 1B is a detail of FIG. 1, depicting the details of a
dropleg system to introduce solids into the pipeline to form a
slurry. Alternative solids introduction apparatus may also be
used.
[0021] FIG. 2 depicts a typical network configuration comprising
three loops entering the refining plant.
[0022] FIG. 3 depicts another configuration in which six separate
loops carry material into the refining plant
[0023] FIG. 4 shows the expansion of the system to nine connecting
loops.
[0024] FIG. 5 shows the further expansion of the system to fifteen
loops with the integration of the pipelines into trunk lines for
entering and leaving the plant.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] Biomass is grown crop fiber consisting primarily of
cellulose, hemicellulose and lignin, and includes, without
limitation, grass, switchgrass, straw, corn stover, cane residuals,
general cereal wastes, wood chips and the like, that can be
converted to ethanol (or other products) according to the aforesaid
U.S. Pat. No. 4,461,648 and U.S. Pat. No. 5,916,780, or other known
technology. Thus, as used herein, biomass includes materials that
are not free flowing in their native state, such as
ligno-cellulosic materials. The invention is intended to be used
preferably in connection with the collection and transport of
non-free flowing materials (ligno-cellulosic biomass), as these
materials are conventionally the most intractable from a materials
handling standpoint
[0026] An acre of arable land may produce as much as 18 tons of
biomass per year (sugar cane), and typically 5 tons per acre of
corn stover or switch grass in a temperate climate. To ensure an
adequate supply, a system according to the invention is typically
designed based on 0.67 tons of biomass per acre per year (cereal
grain straw) or 1.34 tons of corn stover. This refers to the
average amount of biomass obtainable, accounting for domestic
disappearance (including the use of biomass for other purposes),
alternative crops, and the like, not the maximum amount that the
land will produce. Calculations based on genetically modified grass
are also included in the Tables below.
[0027] As shown in FIG. 2 through FIG. 5, collection points 20
preferably are in the center, or close to the center, of an
agricultural area from which biomass will be obtained. These
agricultural areas are represented as hexagons in the figures,
although that representation is arbitrary, and some variation in
the size, shape and topography of the collection areas will be
expected. A maximum collection capacity for a facility according to
the invention is preferably in a range of up to 50,000 tons per
day, which could possibly require a network diameter of about 230
miles, or more. The term "network," depicted for example as network
diameter B in FIGS. 2-5, refers to the diameter of the region
bounded by the outermost conduits, for example. The number of
collection points is not critical, and varies depending on the size
of the network, and may range (for example only) between 7 and 100
collection points. Outline 22 is the extent of the agricultural
areas serviced by all of the collection points 20.
[0028] As shown in FIG. 2, the size of the total collection area is
based on plant processing capability. The following projections
have been made based on a plant capacity of about 5,000 tons/day,
12,500 tons/day, 25,000 tons/day, and 40,000 tons/day, resulting in
a distance across the entire collection area in a range of about 50
miles to about 200 miles.
TABLE-US-00001 TABLE 1 (FIG. 2) PLANT SIZE TONS PER DAY BIOMASS
DENSITY TONS/YEAR/ACRE DISTANCE ACROSS FLATS MILES A AVERAGE LOCAL
HAUL MILES D MAX PERIMETER DISTANCE MILES B 4,590 TPD SWITCH
GENETICALLY STRAW GRASS/ MODIFIED RESIDUAL CORN STOVER GRASS 0.667
1.333 2.667 25.4 18.0 12.77 8.47 6.0 4.25 50.8 36.0 25.5
TABLE-US-00002 TABLE 2 (FIG. 3) PLANT SIZE TONS PER DAY BIOMASS
DENSITY TONS/YEAR/ACRE DISTANCE ACROSS FLATS MILES A AVERAGE LOCAL
HAUL MILES D MAX PERIMETER DISTANCE MILES B 12,456 TPD SWITCH
GENETICALLY STRAW GRASS/ MODIFIED RESIDUAL CORN STOVER GRASS 0.667
1.333 2.667 25.4 18.0 12.77 8.47 6.0 4.25 101.6 72.0 51.1
TABLE-US-00003 TABLE 3 (FIG. 4) PLANT SIZE TONS PER DAY BIOMASS
DENSITY TONS/YEAR/ACRE DISTANCE ACROSS FLATS MILES A AVERAGE LOCAL
HAUL MILES D MAX PERIMETER DISTANCE MILES B 24,262 TPD SWITCH
GENETICALLY STRAW GRASS/ MODIFIED RESIDUAL CORN STOVER GRASS 0.667
1.333 2.667 25.4 18.0 12.77 8.47 6.0 4.25 152.4 108.0 76.6
TABLE-US-00004 TABLE 4 (FIG. 5) PLANT SIZE TONS PER DAY BIOMASS
DENSITY TONS/YEAR/ACRE DISTANCE ACROSS FLATS MILES A AVERAGE LOCAL
HAUL MILES D MAX PERIMETER DISTANCE MILES B 40,000 TPD SWITCH
GENETICALLY STRAW GRASS/ MODIFIED RESIDUAL CORN STOVER GRASS 0.667
1.333 2.667 25.4 18.0 12.77 8.47 6.0 4.25 203.2 144.0 102.2
[0029] Biomass feedstocks differ in terms of how much fuel may be
produced from a ton of the feedstock, and in terms of which enzymes
and other techniques are used for refining the feedstock. Typically
40 to 100 gallons of fuel can be produced from a ton of biomass. It
is preferable to have biomass that is approximately uniform in size
collected from the different collection points according to this
invention to ease the task of refining.
[0030] A key advantage of the present invention is that the biomass
is delivered to collection points by truck or farm wagons traveling
a relatively short distance D to the collection points 20. For
example, in a system calculated to accumulate about 12,500 tons of
biomass, comprising 19 collection points, with a little over 25
miles separating the adjacent collection points (distance A), as
shown in FIG. 3, and based on a collection of 0.67 tons of biomass
per acre per year, the average distance D that would be traveled to
a collection site would be on the order of 8.5 miles. This distance
from pick-up points is suitable for local hauling, which can be
done in a variety of ways by farmers. These numbers are for
illustration only and are not to be considered limiting to the
invention.
[0031] After delivery, the biomass is introduced into the slurry at
the collection points 20, for example using a dropleg 24, so that a
slurry is formed with the circulating water, as shown in FIG. 1B.
In FIG. 1B, biomass is introduced to dropleg 24 by conveyor 26,
water is supplied through supply line 28 and the slurry is agitated
by stirrers 32. The slurry is pumped with a booster pump at 34 into
the conduit network. The embodiment described is for illustration
only. It is not necessary to use a dropleg. Alternative means, such
as a star valve, extrusion screw feeder or the like conventional
solids handling means may also be used.
[0032] The biomass is chopped beforehand, or at the collection
point, preferably to a range of 1/2 inch to 11/2 inch. A cane press
or disk refiner may be used to fractionate the biomass so that it
can be more easily contacted with the acid or alkali for pH
adjustment. A cane press is probably more suited for grasses or
straws while the disk refiner might be more applicable for wood
chips.
[0033] The slurry is then transported to the next collection point
by pumps provided at each collection point or at lift stations as
required. The amount of water in the slurry may be determined by
one of ordinary skill in the art, depending on the pump capacity,
pipe size, etc., however, it is contemplated that a slurry having a
solids content of about 5 wt % is sufficiently transportable
through the network of pipes. A standpipe, with a large diameter
relative to the pipes in the network of pipes, may be used to
accommodate pressure variations in the network, or the standpipe
may be used in conjunction with a dropleg, star valve or extrusion
screw feeder to input solids into the network.
[0034] As shown in FIG. 4 and FIG. 5, it may be desirable to
combine the streams entering and leaving the plant into larger
diameter pipes 70 for transport to the centrally located refining
plant to reduce the overall length of the pipe. In that context, it
may be necessary to split the water stream coming from the refining
plant or at later collection points to maintain the water balance.
In this context, "splitting" means dividing a single larger stream
into a plurality of smaller streams. The figures depict joining
streams of slurry transported from two or more of the plurality of
collection points into a single slurry stream directed to the
refining plant and splitting the water removed from the slurry
coming from the refining plant for recirculation.
[0035] Another important aspect of the system is that water, once
charged into the network, including excess recovered process water,
is reused for transport and the amount of water in the system
remains relatively constant, generally without requiring make-up
water. Because biomass contains in a range of about 12 percent to
about 50 percent moisture, the addition of biomass to the system
results in an increase in the amount of circulating water in the
system. A part of this water may be used up in the refining
process, for example as steam, or water may be treated and
discharged, as necessary to maintain a constant amount of water in
the network. In this context, a relatively constant amount of water
will have the meaning ascribed to that term by one of ordinary
skill in the art. Preferably, a relatively constant amount of water
is an amount required to maintain a solids/liquids ratio of less
than 15%. Typically, the amount of water in the system will not
vary over the course of operation more than .+-.5 percent.
[0036] The network of conduits is arranged so that the refining
plant is accessible from all of the collection points via a
continuous path which carries the slurry of biomass and water to
the centrally located refining plant. In FIG. 1, the generalized
loop diagram illustrates the conduits coming into the plant with
feedstock, the water being recovered and fed back into the pipeline
for transporting additional feedstock. In embodiments, the system
is designed so that loops can be added to an existing network of
conduits, as additional refining capacity is added, to bring the
total production to the scale of a small oil refinery processing
90,000 to 100,000 barrels. These numbers are for illustration
purposes only and are not to be considered limiting to the
invention.
[0037] It is preferred that the conduit loops are sized so that
1000 tons/day or more can be collected from collection points in a
single loop. A system may be provided with a plurality of conduit
loops which can be operated independently, so that one or more
loops can be removed from the system, from time to time. In the
same manner additional loops can be added in the event more plant
capacity and/or agricultural area is added.
[0038] The size of the pipes may be determined by one of ordinary
skill in the art. For example, in the system shown in FIG. 3, based
on a system adapted to accumulate approximately 12,500 tons per
day, pipes having a diameter of approximately 24 inches could be
effectively used, transporting slurry at approximately 5
ft/sec.
[0039] FIG. 2 depicts a loop system of three loops, a loop being
defined as a continuous conduit system with each loop passing
through the refiner and at least two collection points. A system of
loops is a plurality of such loops.
[0040] Water is removed from the slurry at the refining plant using
a cane press or other slurry water removal means known in the art,
including without limitation, centrifugal apparatus, extruders,
screens or filters. The water is thereafter recirculated in the
network. In an embodiment depicted in FIG. 1A, solids-liquid
separation is conducted in a solids-liquid separator such as
centrifuge 42. Separated solids are directed to refining plant 10.
Water recovered from the refining process 44 and water removed from
the slurry 46 may be stored in water storage 48 which may then be
used to supply water to the conduit network.
[0041] As noted above, the particular biomass refining technology
used is not critical to the operation of the collection system. A
plant as described in the aforesaid U.S. Pat. Nos. 4,461,648 and
5,916,780 may be used. As noted therein, preconditioning followed
by pretreatment is typically required to initially break the bonds
between the lignin and cellulose. Thus, in the practice of this
invention, acidic or basic circulating water can optionally be used
so that preconditioning is effected in the circulating system. For
an acid solution, a 2% sulfuric acid solution may be suitable for
this purpose, with the exact requirements being determined based on
the skill of one of ordinary skill in the art based on the
feedstock and refining process being used.
[0042] The foregoing description of the preferred embodiments is
for illustration only and is not to be deemed limiting of the
invention, which is defined in the appended claims.
* * * * *