EP3901367A1 - Verfahren zur vorhydrolyse von lignocellulosematerial - Google Patents
Verfahren zur vorhydrolyse von lignocellulosematerial Download PDFInfo
- Publication number
- EP3901367A1 EP3901367A1 EP20397506.5A EP20397506A EP3901367A1 EP 3901367 A1 EP3901367 A1 EP 3901367A1 EP 20397506 A EP20397506 A EP 20397506A EP 3901367 A1 EP3901367 A1 EP 3901367A1
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- Prior art keywords
- steam
- flow
- hydrolysis
- liquid
- reaction
- Prior art date
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- Withdrawn
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- 238000000034 method Methods 0.000 title claims abstract description 45
- 239000012978 lignocellulosic material Substances 0.000 title claims abstract description 16
- 238000006243 chemical reaction Methods 0.000 claims abstract description 37
- 238000006460 hydrolysis reaction Methods 0.000 claims abstract description 36
- 238000010438 heat treatment Methods 0.000 claims abstract description 23
- 239000007788 liquid Substances 0.000 claims abstract description 22
- 230000003301 hydrolyzing effect Effects 0.000 claims abstract description 11
- 230000008016 vaporization Effects 0.000 claims abstract description 3
- 239000002023 wood Substances 0.000 claims description 27
- 230000007062 hydrolysis Effects 0.000 claims description 26
- 239000007789 gas Substances 0.000 claims description 13
- 239000000835 fiber Substances 0.000 claims description 5
- 238000007872 degassing Methods 0.000 claims description 3
- 229920006395 saturated elastomer Polymers 0.000 claims description 3
- 238000013022 venting Methods 0.000 claims 2
- 239000000463 material Substances 0.000 abstract description 8
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 120
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 37
- 238000010411 cooking Methods 0.000 description 21
- 239000002655 kraft paper Substances 0.000 description 18
- 230000008569 process Effects 0.000 description 17
- 239000012071 phase Substances 0.000 description 15
- 239000002253 acid Substances 0.000 description 9
- 238000002347 injection Methods 0.000 description 7
- 239000007924 injection Substances 0.000 description 7
- 229920002488 Hemicellulose Polymers 0.000 description 6
- 230000008901 benefit Effects 0.000 description 6
- 239000000243 solution Substances 0.000 description 6
- 239000000126 substance Substances 0.000 description 6
- 229920005610 lignin Polymers 0.000 description 5
- 235000014633 carbohydrates Nutrition 0.000 description 4
- 239000000413 hydrolysate Substances 0.000 description 4
- 239000000047 product Substances 0.000 description 4
- 238000003860 storage Methods 0.000 description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 150000001720 carbohydrates Chemical class 0.000 description 3
- 239000003153 chemical reaction reagent Substances 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- -1 fodder Substances 0.000 description 3
- 229910052500 inorganic mineral Inorganic materials 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000011707 mineral Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 238000011084 recovery Methods 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- 239000002028 Biomass Substances 0.000 description 2
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 2
- 239000005864 Sulphur Substances 0.000 description 2
- 150000007513 acids Chemical class 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 238000006073 displacement reaction Methods 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 230000008020 evaporation Effects 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 239000007791 liquid phase Substances 0.000 description 2
- 239000012429 reaction media Substances 0.000 description 2
- 230000035484 reaction time Effects 0.000 description 2
- 238000010025 steaming Methods 0.000 description 2
- 235000010269 sulphur dioxide Nutrition 0.000 description 2
- 239000004291 sulphur dioxide Substances 0.000 description 2
- 229920003043 Cellulose fiber Polymers 0.000 description 1
- 238000010793 Steam injection (oil industry) Methods 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 239000008346 aqueous phase Substances 0.000 description 1
- 238000010923 batch production Methods 0.000 description 1
- JCSJTDYCNQHPRJ-MMDFAQQLSA-N beta-D-Xylp-(1->4)-beta-D-Xylp-(1->4)-beta-D-Xylp Chemical compound O[C@@H]1[C@@H](O)[C@H](O)CO[C@H]1O[C@H]1[C@H](O)[C@@H](O)[C@H](O[C@H]2[C@@H]([C@@H](O)[C@H](O)OC2)O)OC1 JCSJTDYCNQHPRJ-MMDFAQQLSA-N 0.000 description 1
- 239000007844 bleaching agent Substances 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 229920002678 cellulose Polymers 0.000 description 1
- 239000001913 cellulose Substances 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000006482 condensation reaction Methods 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 230000009849 deactivation Effects 0.000 description 1
- 239000007857 degradation product Substances 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000007865 diluting Methods 0.000 description 1
- 238000010790 dilution Methods 0.000 description 1
- 239000012895 dilution Substances 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 235000013373 food additive Nutrition 0.000 description 1
- 239000002778 food additive Substances 0.000 description 1
- 239000002029 lignocellulosic biomass Substances 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000000178 monomer Substances 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 210000000056 organ Anatomy 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- 239000000825 pharmaceutical preparation Substances 0.000 description 1
- 229940127557 pharmaceutical product Drugs 0.000 description 1
- 150000002989 phenols Chemical class 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000004537 pulping Methods 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 238000010926 purge Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- GRVFOGOEDUUMBP-UHFFFAOYSA-N sodium sulfide (anhydrous) Chemical compound [Na+].[Na+].[S-2] GRVFOGOEDUUMBP-UHFFFAOYSA-N 0.000 description 1
- 238000003892 spreading Methods 0.000 description 1
- 230000007480 spreading Effects 0.000 description 1
- 125000001273 sulfonato group Chemical group [O-]S(*)(=O)=O 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 239000004753 textile Substances 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 239000011800 void material Substances 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 229920001221 xylan Polymers 0.000 description 1
- 150000004823 xylans Chemical class 0.000 description 1
Images
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
- D21C1/02—Pretreatment of the finely-divided materials before digesting with water or steam
-
- 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
- D21C3/02—Pulping cellulose-containing materials with inorganic bases or alkaline reacting compounds, e.g. sulfate processes
-
- 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
Definitions
- the present invention relates to prehydrolysis of lignocellulosic material.
- the present invention concerns a method of hydrolysing lignocellulosic chip material with SO 2 -steam mixture.
- lignocellulosics namely cellulose, hemicelluloses and lignin must be separated from each other and the fractions to be turned into corresponding intermediate bioproducts, cellulose fiber, carbohydrate solution (hydrolysate) and lignin solution or solids.
- H. Handbook of Pulp prehydrolysis is generally used to selectively remove the hemicelluloses from the lignocellulosic biomass by hydrolysis in water at 160-180 °C, in dilute acid (0.3-0.5% H 2 SO 4 ) at 120-140 °C or in concentrated acid (20-30% HCl) at 40 °C.
- Dilute mineral acids are efficient in hemicellulose hydrolysis, but they bring along corrosion and material problems and have an adverse effect on lignin - deactivation by acid catalyzed condensation reactions - which makes it more difficult to remove lignin and bleach the cellulosic fibers. So far, all the few industrial continuous prehydrolysis-kraft pulp processes use water prehydrolysis prior to the kraft cooking stage.
- Prehydrolysis products from wood are considered to be a source for chemicals, fodder, food additives and pharmaceutical products. Both the high yield of the prehydrolysis released carbohydrate compounds and the efficient production of the high value products are prerequisites for a feasible industrial process.
- SO 2 -water based prehydrolysis has a unique advantage: it sulphonates the low-molecular phenolic compounds to some extent, thus making them hydrophilic and lowering the scaling plugging tendency in prehydrolysis as well as in the hydrolysate refining operation.
- the above described segregates prehydrolysis technology into two areas, the continuous prehydrolysis-kraft process using the water based prehydrolysis and the discontinuous batch prehydrolysis-kraft process using steam-phase prehydrolysis.
- the steam-phase has been a winner so far, but it has one major drawback: it is not possible to use any hydrolyzing agents such as acid SO 2 -water, etc., because there is no aqueous phase to enable transfer, carrying and mixing of chemicals.
- a method for hydrolysing lignocellulosic material in a reaction vessel by a hydrolysis reaction carried out in the presence of steam at a reaction temperature comprises the steps of:
- the present invention provides a method that reduces the use of highly corrosive SO 2 -water and introduces a feasible hydrolysing method with the use of SO 2 -steam mixture in controlled conditions.
- the SO 2 -steam hydrolysis does not reduce the pulp's yield, viscosity, kappa number or pentosane content. Especially is surprising that the pulp yield does not decrease when using the SO 2 -steam hydrolysis.
- the use of SO 2 according to the present invention is the most efficient in view of the SO 2 concentration in the small amount of condensate and chip water (about 1 ton water per 1 ton of dry biomass); this is quite contrary to the situation in the water liquid-phase prehydrolysis, where the SO 2 dilutes in the big amount of water filling the entire reactor (4-5 tons water per 1 ton dry biomass).
- the reactions are most effective when the reagent concentration is high. Achieving high concentration in small amount of diluting reaction media also enables the lowest possible reagent dosage and chemical cost as well as saving in the heating energy needed.
- the present invention combines the hydrolysis reactor input streams, the heating direct steam serves simultaneously as the carrying media for the SO 2 to enter and spread into the reactor content; a very simple operation saves process time, extra equipment and operational steps.
- hydrolysate liquid contains much more monomeric carbohydrates than is the case in water-based auto-hydrolysis. This is technically an important advantage as the water-hydrolysis dissolved poly- and oligomeric carbohydrates must be hydrolysed to monomers later anyway.
- the SO 2 charge needed for the prehydrolysis is allocated so that the last part of the direct steam input flows without SO 2 in order to flush the input pipe/inlet connection and prehydrolysis reaction temperature is reached.
- the SO 2 addition becomes a part of the heating media, i.e. of the input flow of the steam, and is being transferred on the chip particles with condensing steam and thereby absorbed into the chip particles.
- FIGURE 1 illustrates a batch reactor in accordance with at least some embodiments of the present invention.
- hydrolysate liquid is where the hydrolysis reaction products accumulate.
- oven dry wood weight means oven dry wood weight. It is the weight after all the moisture has been evaporated.
- EA means effective alkali. It is the sum of the sodium hydroxide and half of the sodium sulphide in the white liquor.
- dry means non-aqueous
- pressure unit "bar” is absolute pressure.
- pressure difference "bar” is the differential pressure.
- hydrolysis is used for the chemical reaction of removal of hemicelluloses from lignocellulosic material.
- prehydrolysis is the hydrolysis reaction before a cooking process.
- Figure 1 presents a batch digester in accordance with at least some embodiments of the present invention.
- the digester In the starting situation the digester is empty. The process starts by wood chips filling, through the feeding hopper and digester capping valve 1. Often chip packing is intensified by steam jets giving more speed to falling chips. During the chip fill, gases are evacuated out from the middle screens 5, through the cooking circulation pipeline 6. In an embodiment, air is removed from the digester.
- the first heating stage towards reaction temperature and pressure is carried out by low pressure steam through top screens 2, bottom screens 7 and valves 3, 11, 15 and 9, 10, 15.
- the first low pressure steam heating stage elevates the temperature close to the corresponding saturated steam temperature at the prevailing pressure.
- the first heating stage pressure is 3 - 5 bar and the first heating stage temperature is 125 - 150 °C.
- the time for this heating stage is 15 - 45 minutes
- the medium pressure is at least 1 bar higher than the corresponding pressure of saturated steam at reaction temperature of the hydrolysis.
- the medium pressure is 6 - 10 bar.
- the time for this heating stage is 5 - 25 minutes
- the total time for heating to the desired hydrolysis temperature is 20 - 60 minutes, preferably about 45 minutes.
- SO 2 is introduced into the flowing heating steam.
- the pure steam is allowed to fill the reaction vessel and condense onto the chips, after this liquid SO 2 is injected to the steam, then ending the SO 2 injection so that a clear pure steam feed phase is the last part of the heating steam flow.
- SO 2 injection is placed into the steam flow securing that all the pipe lines and valves etc. are above condensing temperature, but on the other hand there is enough pure steam flow to purge all pipelines and valves etc. clean from SO 2 before the end of steam flow.
- the predetermined SO 2 dosage in the SO 2 injection is at least 0.15 % odw, preferably at least 0.20 % odw, for example 0.25 % odw.
- the hydrolysis of the lignocellulosic material is partial.
- the temperature is maintained until a predetermined degree of hydrolysis of the lignocellulosic material has been reached.
- the pentosan content of the pulp is - as a result of the prehydrolysis - less than 4.5 % by weight, in particular less than 4.2 % by weight, for example about 4 to about 3.5 % by weight of the pulp.
- hydrolysis of the lignocellulosic material will lead to a pentosan content of 4 wt-% or under of the mass of the fiber.
- the injection of SO 2 charge takes place by pumping a predetermined mass-flow of liquid SO 2 from pipeline or SO 2 (1) storage 14, through valve 12 into the steam pipe 13 through injection pipe 12b over a predetermined period of time.
- mass flow of liquid SO 2 is very small compared to the tons of steam flow, the liquid SO 2 is immediately and completely vaporized in the steam flow. This means that the flow of steam and gaseous flow is dry, avoiding corrosion and difficult material selections.
- the steam flow into the chip bed digester carries the SO 2 in all the space of the digester as the heating-by-condensing-steam is the main mechanism, local steam pressure decreases and the gradient is withdrawing and spreading steam and SO 2 everywhere.
- the target reaction temperature is 150-175 °C, preferably 160-165 °C and the desired reaction time is 15-60 minutes, preferably about 30 minutes.
- Sulphur dioxide, SO 2 in the steam, absorbed on the chip surface is quickly transferred to the chip interior together with the heat.
- a uniform SO 2 enhanced prehydrolysis is achieved in all parts of the digester - without using any external SO 2 -water, water phase hydrolysis, re-circulations, indirect heating etc.
- the chips After prehydrolysis, the chips are subjected to kraft cooking. As a result of the prehydrolysis carried out as described in the fore-going using steam containing gaseous SO 2 , there is practically no free condensate or water-phase in the digester, and the burden of removing this liquid phase is completely avoided.
- Liquid dry SO 2 is injected from a storage tank directly into the steam pipe/inlet connection into the hydrolysis reactor (batch digester) and the inflowing heating steam carries and distributes the SO 2 all over the reactor space as a part of the steam flow into every part of the chip filled reactor pulled by the pressure gradient generated by the condensing steam on the wood chips.
- the spread SO 2 gas absorbs on the moist chip particle surfaces and subsequently penetrates and diffuses into the wood chips.
- the kraft cooking is carried out as known in the art. It can be a conventional kraft batch cooking, where first white liquor is added and then the reaction vessel is heated, next the white liquor is circulated through screen 5 to cooking circulation pipeline 6 and pumped up to valve 3 and down to valve 9 and fed back into the reaction vessel through screens 2 and 7.
- An option to the conventional kraft batch cooking is a so called "displacement kraft batch cooking" process where several filling and displacements take place.
- the prehydrolysed and cooked - chemically defibrated pulp - is discharged through bottom curve 17 and valve 8 to fibre line feed 16.
- prehydrolysis part may have different process equipment and instrumentation embodiments, such as separate steam connections and lines, different screen designs, flow of steam and SO 2 (g) injection only from bottom or from top, or both and multiple points.
- the present invention has preferred embodiments in batch reactor processes, but it is not limited to only batch process. It is evident that steam-phase hydrolysis could be constructed to be a continuous process when the chip feeding and discharging machine organs are designed and constructed to operate continuously. In that case SO 2 would be injected into the entering steam, in particular medium pressure steam.
- pulp technical results of these experiments are characterized by pulp pentosan content. This is the main quality parameter of this type pulp and it is controlled by the prehydrolysis reaction degree (hydrolytic removal of xylan hemicelluloses from the wood).
- the pulp buying textile industry's standard for prime pulp is pentosan content 3.5-4.0 %. It is evident that this pentosan range is well met at 0.2-0.25 % SO 2 (g) charge.
- pulp yield pulp delignification degree (kappa number), pulp viscosity are at quite the same level regardless of using SO 2 (g).
- SO 2 SO 2
Landscapes
- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Paper (AREA)
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP20397506.5A EP3901367A1 (de) | 2020-04-20 | 2020-04-20 | Verfahren zur vorhydrolyse von lignocellulosematerial |
| PCT/FI2021/050294 WO2021214387A1 (en) | 2020-04-20 | 2021-04-20 | Method for prehydrolysis of lignocellulosic material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP20397506.5A EP3901367A1 (de) | 2020-04-20 | 2020-04-20 | Verfahren zur vorhydrolyse von lignocellulosematerial |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| EP3901367A1 true EP3901367A1 (de) | 2021-10-27 |
Family
ID=70482590
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP20397506.5A Withdrawn EP3901367A1 (de) | 2020-04-20 | 2020-04-20 | Verfahren zur vorhydrolyse von lignocellulosematerial |
Country Status (2)
| Country | Link |
|---|---|
| EP (1) | EP3901367A1 (de) |
| WO (1) | WO2021214387A1 (de) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2065396A (en) * | 1936-03-30 | 1936-12-22 | Brown Co | Chemical pulping process |
| GB734216A (en) * | 1952-02-15 | 1955-07-27 | Procel Sa | Process for the treatment of ligno-cellulosic fibres |
| US3132051A (en) | 1960-06-09 | 1964-05-05 | Ledoga Spa | Continuous process for extracting pentoses from substances containing hemicelluloses |
| US5139617A (en) | 1987-04-21 | 1992-08-18 | Suomen Sokeri Oy | Process for the production of a hemicellulose hydrolysate and special high alpha cellulose pulp |
| FI121237B (fi) | 2008-10-21 | 2010-08-31 | Danisco | Menetelmä ksyloosin ja liukosellun tuottamiseksi |
| US20120064592A1 (en) * | 2011-01-26 | 2012-03-15 | Qteros, Inc. | Biocatalysts synthesizing deregulated cellulases |
| WO2017100907A1 (en) * | 2015-12-18 | 2017-06-22 | Iogen Corporation | Sulfur dioxide and/or sulfurous acid pretreatment |
-
2020
- 2020-04-20 EP EP20397506.5A patent/EP3901367A1/de not_active Withdrawn
-
2021
- 2021-04-20 WO PCT/FI2021/050294 patent/WO2021214387A1/en not_active Ceased
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2065396A (en) * | 1936-03-30 | 1936-12-22 | Brown Co | Chemical pulping process |
| GB734216A (en) * | 1952-02-15 | 1955-07-27 | Procel Sa | Process for the treatment of ligno-cellulosic fibres |
| US3132051A (en) | 1960-06-09 | 1964-05-05 | Ledoga Spa | Continuous process for extracting pentoses from substances containing hemicelluloses |
| US5139617A (en) | 1987-04-21 | 1992-08-18 | Suomen Sokeri Oy | Process for the production of a hemicellulose hydrolysate and special high alpha cellulose pulp |
| FI121237B (fi) | 2008-10-21 | 2010-08-31 | Danisco | Menetelmä ksyloosin ja liukosellun tuottamiseksi |
| US20110192560A1 (en) * | 2008-10-21 | 2011-08-11 | Danisco A/S | Process of producing xylose and dissolving pulp |
| US20120064592A1 (en) * | 2011-01-26 | 2012-03-15 | Qteros, Inc. | Biocatalysts synthesizing deregulated cellulases |
| WO2017100907A1 (en) * | 2015-12-18 | 2017-06-22 | Iogen Corporation | Sulfur dioxide and/or sulfurous acid pretreatment |
Non-Patent Citations (2)
| Title |
|---|
| RADIOTIS ET AL., NWBC, vol. 1, 2011, pages 325 - 365 |
| SCHELL D J ET AL: "A technical and economic analysis of acid-catalyzed steam explosion and dilute sulfuric acid pretreatments using wheat straw or aspen wood chips", APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY ; PART A: ENZYME ENGINEERING AND BIOTECHNOLOGY, HUMANA PRESS INC, NEW YORK, vol. 28 - 29, no. 1, 1 March 1991 (1991-03-01), pages 87 - 97, XP035177040, ISSN: 1559-0291, DOI: 10.1007/BF02922591 * |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2021214387A1 (en) | 2021-10-28 |
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