SE2330079A1 - Method and system for treating biomass - Google Patents
Method and system for treating biomassInfo
- Publication number
- SE2330079A1 SE2330079A1 SE2330079A SE2330079A SE2330079A1 SE 2330079 A1 SE2330079 A1 SE 2330079A1 SE 2330079 A SE2330079 A SE 2330079A SE 2330079 A SE2330079 A SE 2330079A SE 2330079 A1 SE2330079 A1 SE 2330079A1
- Authority
- SE
- Sweden
- Prior art keywords
- sulfur dioxide
- reactor
- biomass material
- impregnation
- partial pressure
- Prior art date
Links
- 239000002028 Biomass Substances 0.000 title claims abstract description 109
- 238000000034 method Methods 0.000 title claims abstract description 49
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 claims abstract description 211
- 239000000463 material Substances 0.000 claims abstract description 96
- LSNNMFCWUKXFEE-UHFFFAOYSA-N Sulfurous acid Chemical compound OS(O)=O LSNNMFCWUKXFEE-UHFFFAOYSA-N 0.000 claims abstract description 34
- 238000010335 hydrothermal treatment Methods 0.000 claims abstract description 24
- 238000005470 impregnation Methods 0.000 claims description 90
- 239000007788 liquid Substances 0.000 claims description 48
- 239000007789 gas Substances 0.000 claims description 23
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 15
- 238000007872 degassing Methods 0.000 claims description 14
- 239000007787 solid Substances 0.000 claims description 6
- 239000000203 mixture Substances 0.000 claims description 5
- 230000001154 acute effect Effects 0.000 claims description 3
- 150000007524 organic acids Chemical class 0.000 claims description 3
- 239000002245 particle Substances 0.000 claims description 3
- 235000010269 sulphur dioxide Nutrition 0.000 description 68
- 239000012071 phase Substances 0.000 description 11
- 239000012855 volatile organic compound Substances 0.000 description 11
- 239000007791 liquid phase Substances 0.000 description 8
- 238000004880 explosion Methods 0.000 description 6
- 238000006460 hydrolysis reaction Methods 0.000 description 5
- 238000000855 fermentation Methods 0.000 description 4
- 230000004151 fermentation Effects 0.000 description 4
- 230000007062 hydrolysis Effects 0.000 description 4
- 238000002791 soaking Methods 0.000 description 4
- 238000007599 discharging Methods 0.000 description 3
- 230000007071 enzymatic hydrolysis Effects 0.000 description 3
- 238000006047 enzymatic hydrolysis reaction Methods 0.000 description 3
- 235000000346 sugar Nutrition 0.000 description 3
- 150000008163 sugars Chemical class 0.000 description 3
- 239000004291 sulphur dioxide Substances 0.000 description 3
- 241000609240 Ambelania acida Species 0.000 description 2
- LSNNMFCWUKXFEE-UHFFFAOYSA-M Bisulfite Chemical compound OS([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-M 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 238000010793 Steam injection (oil industry) Methods 0.000 description 2
- 239000010905 bagasse Substances 0.000 description 2
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 230000003301 hydrolyzing effect Effects 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 239000010902 straw Substances 0.000 description 2
- 238000013022 venting Methods 0.000 description 2
- 239000002023 wood Substances 0.000 description 2
- 229920002488 Hemicellulose Polymers 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- -1 bark Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 229920002678 cellulose Polymers 0.000 description 1
- 239000001913 cellulose Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 235000013399 edible fruits Nutrition 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000010191 image analysis Methods 0.000 description 1
- 239000012978 lignocellulosic material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 238000007669 thermal treatment Methods 0.000 description 1
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C1/00—Pretreatment of the finely-divided materials before digesting
- D21C1/04—Pretreatment of the finely-divided materials before digesting with acid reacting compounds
-
- C—CHEMISTRY; METALLURGY
- C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
- C12M—APPARATUS FOR ENZYMOLOGY OR MICROBIOLOGY; APPARATUS FOR CULTURING MICROORGANISMS FOR PRODUCING BIOMASS, FOR GROWING CELLS OR FOR OBTAINING FERMENTATION OR METABOLIC PRODUCTS, i.e. BIOREACTORS OR FERMENTERS
- C12M45/00—Means for pre-treatment of biological substances
- C12M45/06—Means for pre-treatment of biological substances by chemical means or hydrolysis
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C3/00—Pulping cellulose-containing materials
- D21C3/04—Pulping cellulose-containing materials with acids, acid salts or acid anhydrides
- D21C3/06—Pulping cellulose-containing materials with acids, acid salts or acid anhydrides sulfur dioxide; sulfurous acid; bisulfites sulfites
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C7/00—Digesters
- D21C7/12—Devices for regulating or controlling
-
- C—CHEMISTRY; METALLURGY
- C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
- C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
- C12P2201/00—Pretreatment of cellulosic or lignocellulosic material for subsequent enzymatic treatment or hydrolysis
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E50/00—Technologies for the production of fuel of non-fossil origin
- Y02E50/10—Biofuels, e.g. bio-diesel
Landscapes
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Bioinformatics & Cheminformatics (AREA)
- Chemical & Material Sciences (AREA)
- Zoology (AREA)
- Wood Science & Technology (AREA)
- Sustainable Development (AREA)
- Microbiology (AREA)
- Biotechnology (AREA)
- Biomedical Technology (AREA)
- Biochemistry (AREA)
- General Engineering & Computer Science (AREA)
- General Health & Medical Sciences (AREA)
- Genetics & Genomics (AREA)
- Molecular Biology (AREA)
- Processing Of Solid Wastes (AREA)
Abstract
A method for treating biomass material such as lignocellulose biomass is provided. The method comprises impregnating (201) the biomass material with sulfur dioxide and/or sulfurous acid, and subjecting the biomass material to hydrothermal treatment (202) in a pretreatment reactor. The method further comprises controlling the treatment severity of the hydrothermal treatment by controlling (203) the sulfur dioxide partial pressure in the pretreatment reactor. A system for treating biomass material is also provided.
Description
TECHNICAL FIELD
The invention relates to the field of treating biomass material such as lignocellulose biomass material, which treating comprises impregnating the biomass material with sulfur dioxide and / or sulfurous acid followed by hydrothermal treatment in a pressurized pretreatment
feaCtOf.
BACKGROUND Methods for treating biomass material such as lignocellulose biomass material, which treating
comprises impregnating the biomass material with sulfur dioxide and/ or sulfurous acid
followed by hydrothermal treatment in a pressurized pretreatment reactor are known in the art.
For example, US2016/0312249 discloses a process comprising soaking cellulosic feedstock in a liquid comprising sulfur dioxide and / or sulfurous acid followed by heating the feedstock and pretreating the heated feedstock in a pretreatment reactor. The pH of the feedstock is adjusted
to between 0.5 and 2.5 prior to the pretreatment.
WO2016126185 discloses a catalyzed pretreatment process in which a catalyst is added by impregnating the lignocellulosic material with an acid solution or with a gas such as sulfur dioxide or carbon dioxide gas. The severity of the pretreatment process is controlled by
adjusting a temperature, pressure, residence time and/ or pH of the pretreatment step.
SUMMARY
An object of the invention is to provide an improved method for treating comprises impregnating the biomass material with sulfur dioxide and/ or sulfurous acid followed by hydrothermal treatment/pretreatment in a pressurized reactor. A further object is to achieve
improved control of the severity of the pretreatment in such a method.
These and other objects are achieved by the present invention by means of a method and a
system according to the independent claims.
According to a first aspect of the invention, a method for treating biomass material such as lignocellulose biomass is provided. The method comprises impregnating the biomass material with sulfur dioxide and/ or sulfurous acid, and (after impregnating) subjecting the biomass
material to hydrothermal treatment in a pressurized pretreatment reactor. The method further
comprises controlling the hydrothermal treatment by controlling the sulfur dioxide partial
pressure in the pressurized pretreatment reactor.
In other words, the method comprises feeding the biomass material to an impregnation reactor in which sulfur dioxide and / or sulfurous acid is added for impregnation of the biomass material. The sulfur dioxide may be added to the impregnation reactor in gaseous form. Alternatively, impregnation liquid comprising sulfurous acid and/ or sulfur dioxide absorbed in water may be added to the impregnation reactor. The impregnated biomass material is subjected to hydrothermal treatment at elevated pressure and temperature in a pretreatment reactor, for example by, after impregnating, being fed to a pressurized pretreatment reactor to which steam is also added for the hydrothermal treatment. The hydrothermal treatment, or more specifically the treatment severity of the hydrothermal treatment, is controlled by controlling the sulfur dioxide partial pressure in the pressurized pretreatment reactor. In other words, the sulfur dioxide partial pressure in the pressurized pretreatment reactor is used as a measure of the treatment severity of the hydrothermal treatment, and control of the treatment severity is thus achieved by controlling the partial pressure. Normally, the hydrothermal treatment/pretreatment is carried out in a separate pretreatment reactor, i.e. the method comprises feeding the impregnated biomass material to the pretreatment reactor. It is however foreseeable within the scope of the invention that the impregnating and the pretreatment is carried out in a common reactor, i.e. biomass material, impregnation liquid and steam is added to the same common reactor (a pretreatment reactor).
It is understood that the wording "sulfurous acid and/ or sulfur dioxide absorbed in water” refers to aqueous solutions of sulfur dioxide, which at equilibrium mainly comprises sulfur dioxide and bisulfite ion (HSOy). It is furthermore understood that hydrothermal treatment may also be referred to as pretreatment, or more specifically pre-hydrolysis. Pre-hydrolysis is carried out at milder conditions compared to a hydrolysis process and is used for hydrolyzing the
hemicellulose content of the biomass.
The invention is based on the insight that the control of the treatment severity is much less dependent on the amount of S02 that is charged than what has been earlier believed. The invention is further based on the insight that there is an equilibrium between the S02 in gas phase and the S02 that is dissolved in liquid phase, and further that with a low S02-partial pressure, the sulfur dioxide dissolved in liquid phase will go to gas phase and will not be available for reaction with the biomass material. This is largely independent from the amount of S02 added. The invention is further based on the insight that although there is an equilibrium
between sulfur dioxide dissolved in liquid and sulfur dioxide in gas phase, it is easier for the
sulfur dioxide to go from liquid phase to gas phase than the opposite. This is particularly the case when the biomass material is impregnated with S02 in gas phase where S02 needs to penetrate the pores of the material before being able to go to the liquid phase. Due to physical constraints, such penetration is more difficult than the opposite (S02 leaving the pores to the gas phase). The inventors have thus realized that it is important to control the S02-partial pressure to avoid that
S02 leaves the liquid phase/ the material.
The biomass material may for example be of woody origin, for example wood chips or flakes,
bark, sawdust or agricultural residues such as straw, bagasse or empty fruit bunches.
In embodiments, controlling the sulfur dioxide partial pressure comprises measuring the temperature and pressure in the reactor and estimating the sulfur dioxide partial pressure by
subtracting the steam saturation pressure at said temperature from the pressure.
In embodiments, the sulfur dioxide partial pressure is controlled by adjusting degassing from the pressurized pretreatment reactor. It is understood that the term ”degassing” refers to venting/discharging of gases from the pretreatment reactor. In a pretreatment reactor arranged substantially vertically or at an acute angle relative a vertical direction, such degassing/venting/discharging takes place from an upper portion of pretreatment reactor. Apart from S02, steam and VOC/NCG may be discharged from the pretreatment reactor by means of the degassing. It is understood that a reactor being substantially vertically arranged refers to that a longitudinal/lengthwise direction of the reactor is substantially vertical, for example within +- 10 degrees relative the vertical direction. It is understood that the bottom and top portions of the reactor refer to a lowermost and uppermost portion of the reactor, respectively, as seen in the vertical direction. It is furthermore understood that the lower and upper portions of the reactor refer to portions of the vessel which is arranged at a vertical distance from each other, with the upper portion being arranged vertically above the lower
portion.
Additionally, or alternatively, the sulfur dioxide partial pressure may be controlled by adjusting the amount of sulfur dioxide and/or sulfurous acid added during said step of impregnating. For example, the sulfur dioxide partial pressure may be controlled by adjusting the amount of sulfur dioxide and / or sulfurous acid added during said step of impregnating while keeping degassing
from the pretreatment reactor constant.
In embodiments, the method further comprises determining the VOC content in gases discharged from the pressurized pretreatment reactor, wherein said sulfur dioxide partial pressure is controlled at least partly on basis of said VOC content. In other words, the VOC content in gas degassed from the pretreatment reactor and / or in gas discharged from the pretreatment reactor along with hydrothermally treated biomass material may be determined, and the sulfur dioxide partial pressure may be controlled on the basis of the VOC content alone or in combination with other parameters (such as one or more of the at least one parameter
described in the following paragraph).
In embodiments, the method further comprises determining a composition of the hydrothermally treated biomass material to determine at least one parameter indicative of dissolved solid content in relation to the total solid content and / or pH value and / or organic acid content and/ or conductivity and / or particle size. The at least one parameter can be determined by measuring pH, conductivity, by analyzing the slurry (the hydrothermally treated biomass) for instance using image analysis. The sulfur dioxide partial pressure is controlled at least partly on
basis of said least one parameter.
In embodiments, the sulfur dioxide partial pressure is controlled towards a set value within an
interval 0.5-4.5 bar, or 1-3.5 bar, or 1-2.4 bar.
In embodiments, the method comprises discharging the material from the pretreatment reactor using a steam explosion discharge device which comprises a blow valve/discharge nozzle through which the biomass material is discharged while undergoing a rapid pressure reduction, for instance to atmospheric pressure. In embodiments, the method further comprises separating the blow steam (which is discharged from the blow valve along with the biomass) from the biomass with a separator, for example a cyclone or a centrifuge. Alternatively, the biomass material may be discharged into a blow tank from which blow steam is vented off. Blow steam in this context refers to a mixture of (water) steam and volatile organic compounds released from the biomass material during thermal treatment / steam explosion discharge of the biomass material. The blow steam also comprises sulfur dioxide which means that the blow steam is
advantageously recycled to recover the sulfur dioxide for use as part of the impregnation liquid.
In embodiments, the method further comprises subjecting the steam exploded biomass to enzymatic hydrolysis for hydrolyzing the cellulose to sugars, and thereafter an optional fermentation stage. Enzymatic hydrolysis and fermentation stages are well known in the art and
will not be described in further detail here.
In embodiments, the method further comprises, prior to said impregnating, compressing the biomass material, wherein said impregnating comprises expanding the biomass material, wherein sulfur dioxide and/ or sulfurous acid is added to the biomass material during and/ or after said expanding. For example, the biomass material may, after compressing, be fed into an impregnation reactor such that the biomass material expands in the impregnation reactor. The sulfur dioxide and/or sulfurous acid may be added to the biomass material in the impregnation reactor by means of injecting or spraying an impregnation liquid comprising sulfur dioxide adsorbed in water and/or sulfurous acid into the impregnation reactor onto the biomass
material, preferably while the biomass material expands into the impregnation reactor.
In embodiments, the method further comprises, after the compressing, feeding the biomass material into an impregnation reactor such that the biomass material expands into the impregnation reactor, wherein the impregnation reactor is at least partly filled with impregnation liquid up to a liquid level, the biomass material being fed into said impregnation reactor at a lower level than said liquid level, the impregnation liquid comprising sulfur dioxide
adsorbed in water and/or sulfurous acid.
The inventors have realized that it is important to have an efficient impregnation so that the S02 is dissolved in the liquid phase and the material is fully impregnated (not only on the liquid layer on the surface of the biomass material). The inventors have realized that if the material is not fully impregnated, it will be necessary to set the S02 partial pressure at a higher level to increase the diffusion of the S02 and sulfurous acid (by increasing the gradient between the gas phase and the liquid layer). The above-described embodiments in which the biomass material is compressed and thereafter expanded are advantageous since they have proven to require a lower S02 partial pressure compared to for example impregnation with S02 in gas phase or
soaking in impregnation liquid.
In embodiments where the impregnation reactor is arranged (with its lengthwise direction/longitudinal axis) substantially vertically or at an acute angle relative a vertical direction, the method further comprises conveying the biomass material upwards in the impregnation reactor towards an outlet at an upper portion of the impregnation reactor where
the biomass material is discharged and fed to the pressurized reactor.
In embodiments wherein the biomass material is impregnated with an impregnation liquid
comprising sulfurous acid and/ or sulfur dioxide absorbed in water, the method further
comprises controlling a concentration of the impregnation liquid to be higher (for example 10- 30% higher) than an equilibrium concentration corresponding to the estimated sulfur dioxide partial pressure. Such a concentration may be referred to as a "sulfur dioxide concentration” but takes into account not only the actual sulfur dioxide content, but also the concentrations of bisulfite ion and sulfurous acid (and other compounds formed from sulfur dioxide, if present) on a molar basis converted into a corresponding concentration of sulfur dioxide. It is understood that an upper limit of the sulfur dioxide concentration is determined by the saturation
COrlCerltratlOrl at trle Current temperature.
In embodiments wherein the biomass material is impregnated with an impregnation liquid comprising sulfurous acid and/ or sulfur dioxide absorbed in water, the method further comprises controlling the concentration of the impregnation liquid is controlled to be higher than a concentration corresponding to a target sulfur dioxide concentration in the impregnated
biomass material.
The two embodiments described above where the concentration of the impregnation liquid is higher than an equilibrium concentration or target sulfur dioxide concentration are based on the insight that it is not the charge of S02 per kg material that is important but the concentration in the liquid phase. A reason is that it the transfer from the raw material liquid phase to the gas phase goes faster than the opposite and it will be faster to reach the equilibrium and a more stable equilibrium if the sulfur dioxide concentration in the liquid is higher than equilibrium or
target COrlCerltratlOrl.
In embodiments wherein the biomass material is impregnated with an impregnation liquid comprising sulfurous acid and/ or sulfur dioxide absorbed in water, the biomass material is not necessarily compressed and expanded into a impregnation reactor, but can instead be
impregnated by means of soaking the biomass material in a soaking vessel.
According to a second aspect of the invention, a system for treating biomass such as lignocellulose biomass is provided. The system comprises an impregnation reactor, a pressurized pretreatment reactor and a control system. The impregnation reactor comprises means for adding sulfur dioxide in gaseous form and/or means for adding an impregnation liquid comprising sulfurous acid and / or sulfur dioxide absorbed in water. The pressurized pretreatment reactor is arranged to subject the impregnated biomass material to hydrothermal treatment at elevated temperature and pressure, the pressurized pretreatment reactor being
provided with a controllable degassing device for controlling a flow of gases emitted from an
upper portion of the pressurized pretreatment reactor. The control system is configured to control the sulfur dioxide partial pressure in the pressurized pretreatment reactor by means of controlling the degassing device and/ or by controlling the means for adding sulfur dioxide or
impregnation liquid.
The above-described methods and systems are advantageously continuous, i.e. the steps of the methods are carried out continuously and the devices of the systems are configured to operate
continuously.
The features of the embodiments described above are combinable in any practically realizable way to form embodiments having combinations of these features. Further, all features and advantages of embodiments described above with reference to the first aspect of the invention may be applied in corresponding embodiments of the system according to the second aspect of
the invention and vice versa.
BRIEF DESCRIPTION OF THE DRAWINGS Above discussed and other aspects of the present invention will now be described in more detail using the appended drawings, which show presently preferred embodiments of the invention, wherein:
fig. 1 shows a schematic illustration of an embodiment of the system according to the second aspect ofthe invention;
fig. 2 shows a flow chart of an embodiment of the method according to the first aspect of the invention.
fig. 3 shows a flow chart of another embodiment of the method according to the first
aspect of the invention.
DETAILED DESCRIPTION Fig. 1 shows a schematic illustration of an embodiment of the system according to the second
aspect of the invention.
Raw material A (lignocellulose biomass material, for example wood, bark, bagasse or straw) is fed to the plug screw feeder 106 for compressing and transporting the biomass material into the impregnation reactor/tower 101 which is substantially vertically arranged. The plug screw feeder compresses the biomass material to a tight plug which expands when it leaves the tapered screw
and enters impregnation reactor 101 at inlet 101c. The material expansion will cause a sponge
effect and sulfur dioxide and/ or sulfurous acid is rapidly sucked into the porous structure of the
biomass.
The impregnation reactor 101 comprises an inlet 102 for adding an impregnation liquid B comprising sulfurous acid and/ or sulfur dioxide absorbed in water. The flow of impregnation liquid is controllable using electrically controllable valve 102a. As can be seen in fig. 1, the inlet 102 is vertically aligned with inlet 101c/ plug screw feeder 106 such that the impregnation liquid is injected onto the biomass material while expanding into the reactor 101. This could be described as the impregnation liquid being “sprayed” onto the biomass material (although inlet
102 is normally not a spray nozzle).
Optionally, the impregnation reactor 101 is partly filled with impregnation liquid up to a liquid level 101a, which liquid level is above the inlet 101c such that the biomass material is fed into
impregnation liquid while undergoing expansion.
Typical operating conditions for the impregnation reactor are as follows:
- Concentration in the impregnation liquid corresponds to 28-165 g sulphur dioxide /l , preferably 40-113 g sulphur dioxide /l, or 56-79 g sulphur dioxide /l.
- Mass ofsulphur dioxide in the biomass material after impregnation 1 - 100 kg SOg/metric ton dry biomass material, preferably 5 - 30 kg SOg/metric ton dry biomass material, or 8 - 20 kg SOg/metric ton dry biomass material.
- Impregnation liquid temperature 5 - 60 °C, preferably 20 - 50 °C or 30 - 40 °C.
- Residence time in the impregnation reactor is 20s - 60 minutes, preferably 20s - 30
minutes or 20s - 5 minutes or 20s-50s.
The impregnation reactor is further provided with a conveyor screw 116 arranged to transport the biomass material upwards in the impregnation reactor towards an outlet 101b at an upper portion of the impregnation reactor where the biomass material is discharged to a transport screw 107 for transporting the biomass to a second plug screw feeder 108 which in turn feeds a pressurized pretreatment reactor 103. The conical plug screw feeder 108 compresses the biomass to a gas-tight plug which seals the pressure of the reactor 103 to the atmospheric. The plug screw feeder 108 may optionally be replaced with other technical solutions such as a rotary lock feeder or a lock hopper system. The pretreatment reactor is substantially vertically arranged. Biomass from the plug screw 108 falls by gravity inside the reactor 103 and piles up inside the reactor. The biomass pile slowly moves downwards as it is continuously emptied in the bottom of the reactor
103 with a discharge screw 113. Steam C is added to a lower portion of the reactor 103 by means
of steam injection nozzle 111b. The steam flow is controlled by valve 111a which may be electrically controllable. The steam heats the biomass inside the reactor 103 such that the biomass is subjected to hydrothermal treatment (pre-hydrolysis) at elevated pressure and temperature.
As indicated in fig. 1, dewatering of the biomass takes place in screws 106-108.
A discharge device is formed by discharge screw 113 arranged at the bottom portion of the reactor and a thereto connected steam explosion device 114, 114a. The discharge screw 113 continuously empties the bottom of the reactor. The discharge screw is of the pressure-sealing type, i.e. is gas- tight just like the plug screw feeder 108 which means that no steam passes concurrently with biomass to the discharge chamber 114 ofthe steam explosion device, which further comprises a blow valve/discharge nozzle 115. The steam explosion device further comprises a transport screw 114a arranged in the discharge chamber to convey the biomass towards the blow
valve/discharge nozzle 1 15.
Typical operating conditions for the pretreatment reactor are as follows: - Temperature in reactor: 160-225 OC, preferably 190-210 OC - Pressure: corresponding pressure 5 - 30 bar(g) - Residence time: 1 min - 3 hours, preferably 3-30 minutes
- Delta pressure at discharge nozzle: 2-30 bar, preferably 2-15 bar or 2-10 bar.
Accumulated VOC/NCG, excess steam and S02 in the gas phase of reactor 103 are vented off (“degassed”) from the top portion 103a of the vessel. An electrically controllable valve 104 (also referred to herein as a controllable degassing device) is provided to allow control ofthe vented
off gases.
Optionally, the vented off gases are led to the discharge chamber 114 via a conduit 110 connecting the valve 104 with the discharge chamber 114,
A steam injection device 112b is provided which is connected to discharge chamber 114 to provide (fresh non-recirculated) discharge steam E to the discharge chamber 107a for control of
the steam explosion discharge over discharge nozzle 115.
A pressure and temperature sensor 109 arranged at the top portion 103a of the vessel. The valves 102a and 104 and sensor 109 are electrically connected to a control system 105. The control system 105 is configured to calculate a steam saturation pressure based on pressure and
temperature in the reactor 103 measured by sensor 109, and to estimate the sulfur dioxide partial
pressure by the subtracting the steam saturation pressure from the pressure measured by sensor 109. The control system 105 is further configured to control the sulfur dioxide partial pressure towards a set value within an interval 0.5-4.5 bar, or 1-3.5 bar, or 1-2.4 bar, the suflur dioxide partial pressure being controlled by controlling valve 104 to adjust degassing from the pretreatment reactor 103, and/or by controlling the valve 102a to adjust the amount of
impregnation liquid added into the impregnation reactor 101.
Optionally, the control system 105 is further connected to motor 116a driving the conveyor screw 116 to control the residence time in the impregnation reactor 101. Control system 105 may also be connected to valve 111a and/ or to valve 112a to control the steam flow to the pretreatment reactor and/ or discharge chamber 114. Adjusting the residence time and/ or the amount of steam flow to the pretreatment reactor (and to the discharge chamber if conduit 110 is present) will also
control the S02 partial pressure.
Steam exploded biomass material is discharged from discharge nozzle 115 along with blow steam to a blow tank (not shown in the figure) from which the blow steam is vented off The blow steam may optionally be fed to an optional S02 recovery system (not shown in the figure) for recycling
of S02 to the impregnation reactor 101.
The system may further comprise an enzymatic hydrolysis stage (not shown in the figure) arranged to receive biomass material from the blow tank, and optionally also a fermentation stage (not shown in the figure) arranged to receive material comprising sugars from the
hydrolysis stage for fermentation of the sugars.
An alternative embodiment corresponds to the above-described embodiment in fig. 1 except that impregnation reactor 101 is replaced with an impregnation reactor provided with one or more inlets for adding sulfur dioxide in gaseous form rather than the inlet 102 for adding impregnation liquid, i.e. the biomass material is impregnated with sulfur dioxide in gaseous form
in this alternative embodiment.
Fig. 2 shows a flow chart of an embodiment of the method according to the first aspect of the invention. The method comprises impregnating 201 the lignocellulose biomass material, and after impregnating subjecting the biomass material to hydrothermal treatment 202 pretreatment reactor. The impregnation 201 and hydrothermal treatment 202 steps are carried
out as described above with reference to fig. 1. The method further comprises controlling 203
11
the treatment severity of the hydrothermal treatment by controlling the sulfur dioxide partial
pressure in the pretreatment reactor. The step of controlling comprises the sub-steps of:
estimating 203a the sulfur dioxide partial pressure by subtracting the steam saturation pressure (calculated on the basis of the current temperature in the pretreatment reactor) from the pressure in the pretreatment reactor;
comparing 203b the estimated sulfur dioxide partial pressure with a set value; controlling 203c the charge of impregnation liquid (comprising sulfur dioxide and / or sulfurous acid) added in the impregnation step 201 based on the result ofthe comparing 203b and/ or
controlling 203d the degassing from the pretreatment reactor based on the result of the
comparing 203b.
Fig. 3 shows a flow chart of another embodiment of the method according to the first aspect of the
invention. This embodiment comprises impregnating and hydrothermal treatment steps 301, 302
corresponding to steps 201, 202 in fig. 2. The step of controlling 303 the treatment severity of the
hydrothermal treatment by controlling the sulfur dioxide partial pressure in the pretreatment
reactor differs from the embodiment in fig. 2 however. The step of controlling 303 comprises the
following substeps:
estimating 303a the sulfur dioxide partial pressure by subtracting the steam saturation pressure (calculated on the basis of the current temperature in the pretreatment reactor) from the pressure in the pretreatment reactor;
optionally determining 303b the VOC content in gases discharged from the pretreatment reactor,
optionally determining 303c a composition of the hydrothermally treated biomass material to determine at least one parameter indicative of dissolved solid content in relation to the total solid content, pH value, organic acid content, conductivity and/ or particle size
controlling 303d the charge of impregnation liquid (comprising sulfur dioxide and/or sulfurous acid) added in the impregnation step 301 and/or the degassing from the pretreatment reactor based on a comparison between the estimated S02 partial pressure from step 303a with a set value and/or based on the determined VOC content and/or based on the at least one parameter. The determining ofVOC content and/or the at least one parameter can be used to determine the set value for the S02 partial pressure, or the VOC content and/or the at least one parameter may be used directly as inputs in the
control step 303d.
12
The steps 303b and 303c ofdetermining the VOC content and composition do not need to be part of the “control loop” in fig. 3, but can be performed less frequently to provide basis for determining
the S02 partial pressure set value
The above-described embodiments are continuous, i.e. the method steps are carried out continuously and the devices of the systems are configured to operate continuously unless noted
otherwise (steps 303b, 303c for instance).
The description above and the appended drawings are to be considered as non-limiting examples of the invention. The person skilled in the art realizes that several changes and modifications may be made within the scope of the invention. For example, the impregnation does not necessarily need to be carried out using an impregnation liquid and
compression / expansion of the biomass material. On the contrary, the impregnation may be
carried out with gas phase S02 and/or without compression/expansion.
Claims (14)
1. Method for treating biomass material, comprising: - impregnating (201; 301) the biomass material with sulfur dioxide and/or sulfurous acid, and - subjecting the biomass material to hydrothermal treatment (202; 302) in a pretreatment reactor, further comprising controlling (203; 303) the hydrothermal treatment by controlling the sulfur dioxide partial pressure in the pretreatment reactor.
2. Method according to any of the preceding claims, wherein said controlling (203; 303) the sulfur dioxide partial pressure comprises adjusting degassing (203d; 303d) from the pretreatment feaCtOf.
3. Method according to claim 1 or 2, wherein said controlling (203; 303) the sulfur dioxide partial pressure comprises adjusting (203c; 303d) the amount of sulfur dioxide and/or sulfurous acid added during said step of impregnating.
4. Method according to any of the preceding claims, further comprising determining (303b) the VOC content in gases discharged from the pretreatment reactor, wherein said sulfur dioxide partial pressure is controlled (303) at least partly on basis of said VOC content.
5. Method according to any of the preceding claims, further comprising determining (303c) a composition of the hydrothermally treated biomass material to determine at least one parameter indicative of dissolved solid content in relation to the total solid content, pH value, organic acid content, conductivity and/ or particle size, wherein said sulfur dioxide partial pressure is controlled (303) at least partly on basis of said least one parameter.
6. Method according to any of the preceding claims, wherein said sulfur dioxide partial pressure is controlled (203b) towards a set value within an interval 0.5-4.5 bar, or 1-3.bar, or 1-2.4 bar.
7. Method according to any of the preceding claims, further comprising, prior to said impregnating, compressing the biomass material, wherein said impregnating comprises expanding the biomass material, wherein sulfur dioxide and / or sulfurous acid is added to the biomass material during and/ or after said expanding.
Method according to claim 7, further comprising, after said compressing, feeding the biomass material into an impregnation reactor (101) such that the biomass material expands into the impregnation reactor, wherein the sulfur dioxide and / or sulfurous acid is added to the biomass material in the impregnation reactor by means of injecting an impregnation liquid comprising sulfur dioxide adsorbed in water and/or sulfurous acid into the impregnation reactor.
Method according to claim 7, further comprising, after said compressing, feeding the biomass material into an impregnation reactor (101) such that the biomass material expands into the impregnation reactor, wherein said impregnation reactor is at least partly filled with impregnation liquid up to a liquid level (101a), the biomass material being fed into said impregnation reactor at a lower level than said liquid level, the impregnation liquid comprising sulfur dioxide adsorbed in water and/or sulfurous acid.
Method according to claim 8 or 9, wherein the impregnation reactor (101) is arranged substantially vertically or at an acute angle relative a vertical direction, further comprising conveying the biomass material upwards in the impregnation reactor towards an outlet at an upper portion of the impregnation reactor where the biomass material is discharged and fed to the pretreatment reactor (103).
Method according to any ofthe preceding claims, wherein said controlling (203; 303) the sulfur dioxide partial pressure comprises measuring the temperature and pressure in the pretreatment reactor and estimating (203a; 303a) the sulfur dioxide partial pressure by subtracting the steam saturation pressure at said temperature from the pressure.
Method according to any of the preceding claims, wherein the biomass material is impregnated (201; 301) with an impregnation liquid comprising sulfurous acid and/or sulfur dioxide absorbed in water, wherein a concentration of sulfur dioxide in said impregnation liquid is controlled to be higher than an equilibrium concentration corresponding to the estimated sulfur dioxide partial pressure.
Method according to any of claims 1-11, wherein the biomass material is impregnated (201; 301) with an impregnation liquid comprising sulfurous acid and/or sulfur dioxide absorbed in water, wherein a concentration of sulfur dioxide in said impregnation liquid is controlled to be higher than a concentration corresponding to a target sulfur dioxide concentration in the impregnated biomass material.
14. System for treating biomass comprising: an impregnation reactor (101) comprising means (102) for adding sulfur dioxide in gaseous form or an impregnation liquid comprising sulfurous acid and/or sulfur dioxide absorbed in water; a pretreatment reactor (103) arranged to subject the impregnated biomass material to hydrothermal treatment, the pretreatment reactor being provided with a controllable degassing device (104) for controlling a flow of gases emitted from an upper portion of the pretreatment reactor, and a control system (105) configured to control the sulfur dioxide partial pressure in the pretreatment reactor by means of controlling the degassing device (104) and / or by controlling the means (102) for adding sulfur dioxide or impregnation liquid.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE2330079A SE2330079A1 (en) | 2023-02-14 | 2023-02-14 | Method and system for treating biomass |
| PCT/SE2024/050090 WO2024172717A1 (en) | 2023-02-14 | 2024-02-02 | Method and system for treating biomass |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE2330079A SE2330079A1 (en) | 2023-02-14 | 2023-02-14 | Method and system for treating biomass |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| SE2330079A1 true SE2330079A1 (en) | 2024-08-15 |
Family
ID=89941214
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| SE2330079A SE2330079A1 (en) | 2023-02-14 | 2023-02-14 | Method and system for treating biomass |
Country Status (2)
| Country | Link |
|---|---|
| SE (1) | SE2330079A1 (en) |
| WO (1) | WO2024172717A1 (en) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE416061B (en) * | 1978-08-23 | 1980-11-24 | Mo Och Domsjoe Ab | Process for controlling the sulphite pulping process |
| WO2017100907A1 (en) * | 2015-12-18 | 2017-06-22 | Iogen Corporation | Sulfur dioxide and/or sulfurous acid pretreatment |
| WO2017136915A1 (en) * | 2016-02-10 | 2017-08-17 | Iogen Corporation | Pretreatment of lignocellulosic biomass with sulfur dioxide and/or sulfurous acid |
| EP3333311A1 (en) * | 2016-12-08 | 2018-06-13 | Valmet AB | Method for impregnating biomass and device for impregnating biomass |
| EP3859079A1 (en) * | 2020-02-03 | 2021-08-04 | Sekab E-Technology AB | Arrangement and method for pretreatment of biomass |
| US20220017928A1 (en) * | 2018-11-09 | 2022-01-20 | Iogen Corporation | Pretreatment of softwood |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FI121237B (en) * | 2008-10-21 | 2010-08-31 | Danisco | A process for producing xylose and soluble pulp |
| WO2016126185A1 (en) | 2015-02-02 | 2016-08-11 | Sekab E-Technology Ab | Controlling the pretreatment of a softwood starting material |
| BR112017017769A2 (en) | 2015-03-16 | 2018-04-03 | Iogen Corp | processes for producing a fermentation product from a lignocellulosic feedstock and for producing ethanol from a lignocellulosic feedstock. |
| CA3094413A1 (en) * | 2018-04-06 | 2019-10-10 | Iogen Corporation | Pretreatment with lignosulfonic acid |
-
2023
- 2023-02-14 SE SE2330079A patent/SE2330079A1/en unknown
-
2024
- 2024-02-02 WO PCT/SE2024/050090 patent/WO2024172717A1/en unknown
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE416061B (en) * | 1978-08-23 | 1980-11-24 | Mo Och Domsjoe Ab | Process for controlling the sulphite pulping process |
| WO2017100907A1 (en) * | 2015-12-18 | 2017-06-22 | Iogen Corporation | Sulfur dioxide and/or sulfurous acid pretreatment |
| WO2017136915A1 (en) * | 2016-02-10 | 2017-08-17 | Iogen Corporation | Pretreatment of lignocellulosic biomass with sulfur dioxide and/or sulfurous acid |
| EP3333311A1 (en) * | 2016-12-08 | 2018-06-13 | Valmet AB | Method for impregnating biomass and device for impregnating biomass |
| US20220017928A1 (en) * | 2018-11-09 | 2022-01-20 | Iogen Corporation | Pretreatment of softwood |
| EP3859079A1 (en) * | 2020-02-03 | 2021-08-04 | Sekab E-Technology AB | Arrangement and method for pretreatment of biomass |
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| Publication number | Publication date |
|---|---|
| WO2024172717A1 (en) | 2024-08-22 |
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