U.S. patent application number 13/929858 was filed with the patent office on 2013-10-31 for process for producing alcohol and other bioproducts from biomass extracts in a kraft pulp mill.
The applicant listed for this patent is API Intellectual Property Holdings, LLC. Invention is credited to Vesa PYLKKANEN, Theodora RETSINA.
Application Number | 20130283795 13/929858 |
Document ID | / |
Family ID | 43857135 |
Filed Date | 2013-10-31 |
United States Patent
Application |
20130283795 |
Kind Code |
A1 |
RETSINA; Theodora ; et
al. |
October 31, 2013 |
PROCESS FOR PRODUCING ALCOHOL AND OTHER BIOPRODUCTS FROM BIOMASS
EXTRACTS IN A KRAFT PULP MILL
Abstract
A method for the production of alcohol and other bioproducts
from power boiler woody biomass extract containing hemicelluloses,
with or without combining extract from wood prior to Kraft cooking.
The process is integrated with the host Kraft pulp mill plant
process to minimize the heat loss from extracting hemicelluloses
and the energy used in the process.
Inventors: |
RETSINA; Theodora; (Atlanta,
GA) ; PYLKKANEN; Vesa; (Atlanta, GA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
API Intellectual Property Holdings, LLC |
Atlanta |
GA |
US |
|
|
Family ID: |
43857135 |
Appl. No.: |
13/929858 |
Filed: |
June 28, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13500917 |
Apr 9, 2012 |
8518213 |
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PCT/US2010/051759 |
Oct 7, 2010 |
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13929858 |
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Current U.S.
Class: |
60/645 ; 110/218;
435/160; 435/162; 435/165 |
Current CPC
Class: |
Y02E 50/16 20130101;
Y02E 50/17 20130101; C12P 7/10 20130101; C12N 1/22 20130101; F01K
25/00 20130101; C12P 7/16 20130101; C12P 7/14 20130101; Y02E 50/10
20130101; D21C 11/0007 20130101; F23K 5/00 20130101 |
Class at
Publication: |
60/645 ; 435/162;
435/165; 435/160; 110/218 |
International
Class: |
C12P 7/10 20060101
C12P007/10; F23K 5/00 20060101 F23K005/00; F01K 25/00 20060101
F01K025/00; C12P 7/14 20060101 C12P007/14; C12P 7/16 20060101
C12P007/16 |
Claims
1. A process for the production of alcohol from biomass, said
process comprising: (a) extracting a biomass feedstock with steam
or hot water, to generate a first liquid hydrolyzate and a first
extracted-solids stream; (b) extracting wood chips with steam in a
digester, to generate a second liquid hydrolyzate and a second
extracted-solids stream; (c) combining said first liquid
hydrolyzate and said second liquid hydrolyzate to generate a
combined hydrolyzate; (d) further hydrolyzing said combined
hydrolyzate with an acid or enzymes to convert oligomeric
hemicelluloses into monomer sugars; and (e) fermenting said monomer
sugars to produce an alcohol.
2. The process of claim 1, wherein said alcohol is ethanol or
butanol.
3. The process of claim 1, said process further comprising
dewatering and combusting said first extracted-solids stream to
produce power.
4. The process of claim 1, said process further comprising pulping
said second extracted-solids stream to produce pulp.
5. A process for the production of alcohol and power from biomass,
said process comprising: (a) extracting a first biomass feedstock
with steam or hot water, to generate a first liquid hydrolyzate and
a first extracted-solids stream; (b) optionally extracting a second
biomass feedstock, in the form of wood chips, with steam in a Kraft
digester, to generate a second liquid hydrolyzate and a second
extracted-solids stream; (c) further hydrolyzing said first liquid
hydrolyzate and, if step (b) is conducted, said second liquid
hydrolyzate, with an acid or enzymes to convert oligomeric
hemicelluloses into monomer sugars; (d) fermenting said monomer
sugars to produce an alcohol; (e) combusting said first
extracted-solids stream to produce power; and (f) if step (b) is
conducted, pulping said second extracted-solids stream to produce
pulp.
6. The process of claim 5, said process further comprising
evaporating said first liquid hydrolyzate and, if step (b) is
conducted, said second liquid hydrolyzate using mechanical-vapor
recompression evaporation.
7. The process of claim 5, wherein said first liquid hydrolyzate
and, if step (b) is conducted, said second liquid hydrolyzate is
each maintained at a pH below 4.8 to volatilize acetic acid during
said evaporating.
8. The process of claim 5, wherein production and purification of
said alcohol is integrated with a host Kraft pulp mill, to minimize
heat loss and energy use.
9. The process of claim 5, wherein a separate multiple-effect
evaporator located at a host Kraft pulp mill is integrated with an
alcohol distillation column for purifying said alcohol.
10. The process of claim 5, said process further comprising
injecting distillation column bottoms into weak black liquor of a
Kraft pulp mill, to concentrate said distillation column
bottoms.
11. The process of claim 5, said process further comprising
combining concentrated distillation column bottoms with said first
extracted-solids stream prior to said combusting.
12. The process of claim 5, wherein step (e) produces high-pressure
steam suitable for a turbine to generate said power, and wherein
used steam from step (e) is recycled to step (b), if conducted,
and/or step (c).
13. A process for the production of alcohol and pulp from biomass,
said process comprising: (a) extracting a first biomass feedstock,
in the form of wood chips, with steam in a Kraft digester, to
generate a first liquid hydrolyzate and a first extracted-solids
stream; (b) optionally extracting a second biomass feedstock with
steam or hot water, to generate a second liquid hydrolyzate and a
second extracted-solids stream; (c) further hydrolyzing said first
liquid hydrolyzate and, if step (b) is conducted, said second
liquid hydrolyzate, with an acid or enzymes to convert oligomeric
hemicelluloses into monomer sugars; (d) fermenting said monomer
sugars to produce an alcohol; (e) pulping said first
extracted-solids stream to produce pulp; and (f) if step (b) is
conducted, combusting said second extracted-solids stream to
produce power.
14. The process of claim 13, said process further comprising
evaporating said first liquid hydrolyzate and, if step (b) is
conducted, said second liquid hydrolyzate using mechanical-vapor
recompression evaporation.
15. The process of claim 13, wherein said first liquid hydrolyzate
and, if step (b) is conducted, said second liquid hydrolyzate is
each maintained at a pH below 4.8 to volatilize acetic acid during
said evaporating.
16. The process of claim 13, wherein production and purification of
said alcohol is integrated with a host Kraft pulp mill, to minimize
heat loss and energy use.
17. The process of claim 13, wherein a separate multiple-effect
evaporator located at a host Kraft pulp mill is integrated with an
alcohol distillation column for purifying said alcohol.
18. The process of claim 13, said process further comprising
injecting distillation column bottoms into weak black liquor of a
Kraft pulp mill, to concentrate said distillation column
bottoms.
19. The process of claim 13, wherein step (b) is conducted, said
process further comprising combining concentrated distillation
column bottoms with said second extracted-solids stream prior to
said combusting.
20. The process of claim 13, wherein step (b) is conducted, wherein
step (f) produces high-pressure steam suitable for a turbine to
generate said power, and wherein used steam from step (f) is
recycled to step (a) and/or step (c).
Description
FIELD OF THE INVENTION
[0001] This invention relates, in general, to the process
extracting and treating of extracts of biomass prior to a biomass
boiler, potentially combined with extract from biomass prior to
Kraft process, and treatment of this extract for production of
alcohol and other bioproducts in a Kraft pulp mill.
BRIEF DESCRIPTION OF THE DRAWINGS
[0002] A more complete understanding of the present invention may
be obtained by reference to the following detailed description when
read in conjunction with the accompanying drawings wherein:
[0003] FIG. 1. illustrates a conceptual flow sheet example of the
invention process.
[0004] FIG. 2. illustrates a typical general arrangement of the
unit operations for mixed biomass derived extract by steam
explosion prior to a power plant combustor.
BACKGROUND OF THE INVENTION
[0005] Renewable power generation from forest residues is commonly
practiced in the forest products industries. The U.S. forest
products industry consumed 27.1 million tons of wood derived
biomass, called "hog fuel", in the generation of steam. By
comparison, the power generation industry used 11.9 million tons of
biomass of which 80% is wood derived. The biomass consumption in
power generation is expected to double in every 10 years until
2030.
[0006] The major wood components are lignin, hemicelluloses and
cellulose. The steam explosion process dissolves predominantly
hemicelluloses in temperatures above 160.degree. C. Hemicelluloses
fraction removed in this process is termed "extract". A
concentration of the extract through evaporation is energy
intensive, although it is currently practiced to produce
molasses.
[0007] Previous research indicates that ethanol, acetic acid and
their byproducts can be derived from the wood extract. Especially
hardwood produces an extract rich in acetic acid and sugars as
taught by Amidon et al. in (U.S. Patent Application No.
2007/0079944 A1, Apr. 12, 2007).
[0008] The current inventors, Retsina; et al. (U.S. Patent Filing
No. 61/175,588) have previously described a steam extraction and
hydrolysis process, in which an alkaline acetate product is
concentrated in reverse osmosis membrane from evaporator
condensate. The clean permeate is further recycled to the host mill
to achieve zero effluent operation. Furthermore, the current
inventors Retsina; et al. (U.S. Patent Application No. 61/219,764)
have described the process integration of the waste heat to temper
power boiler feed water.
[0009] The current inventors found an alternative method to produce
fermented alcohol, ethanol or butanol, from biomass extraction
using steam explosion, followed by vapor recompression evaporation,
acid hydrolysis, fermentation and distillation. The present
inventors have now developed a process, wherein the hemicelluloses
in the power plant biomass extract can be converted to chemical
products in an energy efficient process.
SUMMARY OF THE INVENTION
[0010] The present invention describes a process for the production
of alcohol and other bioproducts from power boiler biomass extract,
combined or not, with extract from the pretreatment of wood chips
prior to Kraft process digestion. Treatment of hemicelluloses in
the extract through hydrolysis, evaporation, fermentation and
distillation steps is used to recover and concentrate alcohol and
acetate products. The process is integrated with the host plant to
reuse water and to minimize process energy and water
consumption.
DETAILED DESCRIPTION OF THE INVENTION
[0011] The first step of the process is biomass extraction. Woody
biomass is charged in a batch or continuous reactor vessel along
with steam and heated to between 5 and 30 atmospheres pressure for
2 or more minutes to obtain 10-30% of wood as dissolved solids. In
one manifestation, this extract is combined with extract from the
Kraft mill digester. In the Kraft mill digester, a first stage of
steam extraction is practiced prior to the Kraft cooking.
[0012] The second step of the process is washing of biomass. The
heated biomass is washed with hot water or condensate and drained
to recover dissolved wood components. The wash filtrate contains
dissolved xylan, glucan, mannan, arbinan, galactan and acetyl
groups in oligomers of hemicelluloses as well as lignin. The wash
filtrate has low organic solids concentration in between 1% and
15%. The majority of the water must be removed before an economic
treatment of hemicelluloses is possible.
[0013] The third step of the process is compaction of the biomass.
The remaining solid biomass is subjected to mechanical pressure
through a plug screw feeder. This compaction dewaters the biomass
to uniform moisture of 60% or less, which is similar to delivered
biomass from the forest.
[0014] The fourth step of the process is low solids evaporation.
Evaporation of the wash filtrate or extract using mechanical vapor
recompression is suitable for low solids concentration up to around
25%, because the boiling point rise is small. Evaporated vapor is
compressed and condensed in the hot side of the evaporator to
produce more evaporation. If the wash filtrate or extract feed
concentration is over 5%, this step may be omitted. When the pH is
kept below acetic acid dissociation point at 4.8, acetic acid, a
fermentation inhibitor, is volatilized to vapor fraction.
[0015] The fifth step of the process is hydrolysis. Sulfuric acid
or enzymes can be used to hydrolyze the sugars, which were
concentrated in the low solids evaporator. Oligomeric
hemicelluloses are converted into monomer sugars and acetyl groups
are released. The hydrolyzate pH is controlled following the
hydrolysis to maintain acetic acid in the unassociated form.
Hydrolysis can be performed in batch or continuous mode. As an
option at the end of this step, the pH may be adjusted with lime or
another chemical and any precipitated solids may be washed and
treated separately.
[0016] The sixth step of the process is post hydrolysis
evaporation. Evaporation using mechanical vapor recompression is
performed to concentrate the hydrolyzate to 15%-35% solids. More of
the remaining acetic acid and water is evaporated in this step.
Under the appropriate economic criteria, this step could be done
with steam evaporation.
[0017] The seventh step of the process is fermentation of wood
sugars. The sugars in the evaporated hydrolyzate are fermented in
continuous or batch tanks with one or more micro-organisms capable
of converting five and six-carbon sugars into alcohol and carbon
dioxide. The majority of acetic acid, which may inhibit
fermentation, was removed in the previous evaporation step. Some
additional acetic acid may be formed in the fermentation steps.
Nutrients and pH adjustment chemicals, as well as make-up
fermentative organism, are added in the fermentors as and if
needed. Carbon dioxide is removed from the fermentors and scrubbed
with cool water for alcohol recovery. This purified gas can be
further compressed and sold as industrial grade carbon dioxide. The
fermentation broth, commonly termed "beer", from the fermentation
step is sent to a distillation column.
[0018] The eighth step of the process is distillation of alcohol.
The beer from the fermentation processes is sent to a distillation
column to separate the alcohol from the solids and residual sugars.
Alcohol leaving as the overhead from the distillation column is
recovered at approximately 50 mass-% strength. The final
concentration of the alcohol product is performed in a rectifying
column and molecular sieve to obtain over 99-mass % alcohol. In one
manifestation, the beer column is integrated in the existing Kraft
mill multiple-effect evaporator train so that it runs as an effect
and avails itself of the multiple effect economy of the Kraft
evaporator.
[0019] The ninth step of the process is the solids concentration
from the stillage. The solids, commonly termed stillage, from the
distillation beer column bottom can be further evaporated in an
optional mechanical vapor concentrator to achieve zero-liquid
discharge operation. The concentrated sludge can be burned in a
biomass boiler to increase steam generation. Alternatively, this
concentration can happen by injecting the distillation bottoms in
the weak black liquor of the existing Kraft mill, so that it is
evaporated using multiple-effect economy in the existing Kraft
evaporator.
[0020] The tenth step of the process is combustion of biomass. The
compacted biomass from the third step and concentrated solids from
the ninth step are fed to a traditional biomass combustion unit.
The heat of combustion is used to raise steam, which drives a steam
turbine to generate electricity, or the steam can be used for the
process.
[0021] In one manifestation of the invention, hydrolysis and
fermentation (the seventh and tenth steps) may be combined in one
step by using a third party proprietary microorganism.
* * * * *