CN102016162A - Prehydrolysis sulfate cooking process - Google Patents
Prehydrolysis sulfate cooking process Download PDFInfo
- Publication number
- CN102016162A CN102016162A CN2009801162710A CN200980116271A CN102016162A CN 102016162 A CN102016162 A CN 102016162A CN 2009801162710 A CN2009801162710 A CN 2009801162710A CN 200980116271 A CN200980116271 A CN 200980116271A CN 102016162 A CN102016162 A CN 102016162A
- Authority
- CN
- China
- Prior art keywords
- pressure
- prehydrolysis
- crust
- boiling
- cellulosic material
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 42
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 title description 8
- 238000010411 cooking Methods 0.000 title description 7
- 239000007788 liquid Substances 0.000 claims abstract description 35
- 239000000463 material Substances 0.000 claims abstract description 23
- 229920005610 lignin Polymers 0.000 claims abstract description 6
- 238000009835 boiling Methods 0.000 claims description 61
- 239000012071 phase Substances 0.000 claims description 15
- 239000012808 vapor phase Substances 0.000 claims description 11
- 230000006837 decompression Effects 0.000 claims description 7
- 229920001131 Pulp (paper) Polymers 0.000 claims description 6
- 238000010923 batch production Methods 0.000 claims 1
- 238000006386 neutralization reaction Methods 0.000 abstract description 17
- 238000002360 preparation method Methods 0.000 abstract description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M sodium hydroxide Inorganic materials [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 21
- 239000003513 alkali Substances 0.000 description 10
- 239000002655 kraft paper Substances 0.000 description 8
- 235000011121 sodium hydroxide Nutrition 0.000 description 8
- 229920002488 Hemicellulose Polymers 0.000 description 7
- 230000007062 hydrolysis Effects 0.000 description 7
- 238000006460 hydrolysis reaction Methods 0.000 description 7
- 239000002023 wood Substances 0.000 description 7
- 239000000413 hydrolysate Substances 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- 229910021653 sulphate ion Inorganic materials 0.000 description 4
- 238000006073 displacement reaction Methods 0.000 description 3
- 239000012530 fluid Substances 0.000 description 3
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 2
- 229920002678 cellulose Polymers 0.000 description 2
- 239000001913 cellulose Substances 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 239000007791 liquid phase Substances 0.000 description 2
- 230000003472 neutralizing effect Effects 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 230000001052 transient effect Effects 0.000 description 2
- 229920003043 Cellulose fiber Polymers 0.000 description 1
- 229920000875 Dissolving pulp Polymers 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 238000005903 acid hydrolysis reaction Methods 0.000 description 1
- 238000004061 bleaching Methods 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 230000003750 conditioning effect Effects 0.000 description 1
- 239000007799 cork Substances 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 239000011121 hardwood Substances 0.000 description 1
- 238000002803 maceration Methods 0.000 description 1
- 150000007522 mineralic acids Chemical class 0.000 description 1
- 150000007524 organic acids Chemical class 0.000 description 1
- 238000004537 pulping Methods 0.000 description 1
- 238000007634 remodeling Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 230000007928 solubilization Effects 0.000 description 1
- 238000005063 solubilization Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 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
- D21C1/02—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
- D21C1/00—Pretreatment of the finely-divided materials before digesting
- D21C1/10—Physical methods for facilitating impregnation
-
- 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
Landscapes
- Paper (AREA)
Abstract
A process for the preparation of prehydrolyzed pulp in a digester from lignin-containing cellulosic material is disclosed. According to the present invention the cellulosic material is prehydrolyzed in a first steam phase at a first pressure to obtain prehydrolyzed cellulosic material. The termination of the prehydrolyzing operation i.e. the neutralization of the prehydrolyzed material is performed by adding an alkaline liquid at the first pressure into the digester followed by at least one pressure reduction.
Description
Technical field
The present invention relates to the boiling method of improved prehydrolysis sulfate (kraft pulp).The invention discloses improving one's methods of the hydrolysis stage that is used to finish prehydrolysis sulphate cook method.More precisely, the end of the hydrolysis stage that the present invention relates in vapor phase, operate, the end in wherein said stage is also carried out in vapor phase.
Background technology
Developed in nineteen thirties and to be used to make prehydrolysis sulfate (kraft pulp) boiling, referring to for example Rydholm, S.E. with the cellulosic special pulps of high content of alpha, Pulping Processes, the 649th～672 page, Interscience Publishers, New York, 1968.Basic thought is to utilize lignification removal to act on the hemicellulose of removing as much as possible from cellulose fibre, thereby obtains the chemical cellulose of high-load.This is essential, because the various terminal uses of this class paper pulp, dissolving pulp for example all can not accept to have the short chain hemicellulose molecule of the molecular structure of random grafting.
Independent prehydrolysis step allows to carry out conditioning desired by changing double cellulosic hydrolysis of hydrolysising condition.In prehydrolysis kraft pulp boiling method, before the second independent boiling step, do not need to carry out lignification removal.Prehydrolysis is carried out as water or vapor phase prehydrolysis, perhaps carries out in the presence of catalyst.In last method, the organic acid that discharges from timber in the method carries out the hydrolysis of major part, and in one method of back, adds a spot of inorganic acid or sulfur dioxide with " assisting " prehydrolysis.In the prehydrolysis stage of carrying out in vapor phase, the chip column in boiling vessel is introduced live (open) steam.Because the balance of matter and energy even have, also just produces considerably less liquid hydrolysate phase, because all condensate all remains in the hole of wood materials.
Traditionally, in reactor, make after the cellulosic material prehydrolysis, use the cellulosic material of alkaline neutralizer neutralizing hydrolysis product and prehydrolysis in reactor, thereby produce the cellulosic material of hydrolysate that is neutralized and the prehydrolysis that is neutralized.All there is hydrolysate in the free fluid outside wood chip and that retain and be fixed on wood chip inside.If wish, before neutralization procedure, can collect partial hydrolysate.In neutralization procedure, the content of preparation boiling vessel is to be used for the follow-up lignification removal that alkaline kraft pulp boiling is carried out that passes through.
The common use of the material of prehydrolysis contains the alkali lye body and neutralizes by displacement or circulation.By select suitable in and alkali charge realize neutralization, this produces in the clear and definite alkalescence and terminal point.Employed suitable neutralization reagent contains caustic soda, and preferably reagent is alkaline kraft pulp cooking liquor, promptly white liquid.Replacement process can for example be undertaken by following: fill boiling vessel with white liquid, make the forward position neutralizing hydrolysis product of this white liquid.In cyclic process, the liquid that will contain alkali pumps in the boiling vessel, thereby from the external displacement hydrolysate of wood chip.Also make itself and contents mixed finish neutralization thus by circulating fluid in boiling vessel.
In main and the function, this neutralization procedure is also as the hemicellulose alkaline solubilization step.Highly basic and high temperature directly dissolve hemicellulose, and on the other hand by so-called stripping reaction forward (end-wise peeling reaction) degradation of hemicellulose.Paper pulp is further purified thus, and this causes higher pulp viscosity and higher chemical cellulose content.In other words, neutralization procedure also partly becomes the alkaline extraction stage before the boiling step.Therefore, the alkali lye/timber in this step is lower than preferably, and for example about 2.5～3.5.
Use alkaline cooking liquor (containing vulcanized sodium and NaOH) to make the cellulosic material lignification removal of the prehydrolysis that is neutralized.Lignification removal's step is conventional kraft pulp cooking process, wherein adds white liquid in boiling vessel and boiling is carried out as single step.
As mentioned above, the acidic hydrolysis stage of prehydrolysis sulfate (kraft pulp) boiling of prior art for example finishes (i.e. neutralization) in the following manner: use white liquid or use some other contain the alkali lye body and fill boiling vessel to carry out pH and change and can be the sulphate cook state of the lignin dissolution of alkalescence from the hemicellulose separation condition/state-transition of acidity.The neutralization of hydrolysis stage promptly finishes to carry out in an identical manner independently, no matter prehydrolysis is to carry out with liquid phase or vapor phase.Above-mentioned two kinds of neutralization method promptly circulate and replace all is consuming time, and this makes that the uniformity of neutralization is relatively poor.
Summary of the invention
Main purpose of the present invention provides and is used for preparing improving one's methods of paper pulp by the cellulosic material that contains lignin, wherein prehydrolysis in vapor phase, carry out and the end (being the neutralization of boiling vessel content) in this prehydrolysis stage also be in vapor phase, carry out to overcome the problem relevant with prior art.According to the present invention, the end of vapor phase is undertaken by following: the akaline liquid under the general pressure (prevailing pressure) is joined in the boiling vessel, temporarily reduce the pressure of this boiling vessel then.Because the effect of decompression, the akaline liquid of adding is evaporated in the gas compartment of boiling vessel, the material of the prehydrolysis in this boiling vessel that neutralizes thus.Below will more specifically describe according to ending phase of the present invention and remodeling thereof.
From the CA 597147 known of short duration pressure declines of use when by the superpressure impregnated timber.The purpose of this method be make air contained in the timber aperture (wood cell) with big strength from wherein overflowing.Pressure is descended once or several times, and can adopt relatively with them maceration extract is heated.The present invention relates in boiling vessel, prepare the method for the paper pulp of prehydrolysis, comprise by the cellulosic material that contains lignin
A) in first vapor phase, under first pressure, make described cellulosic material prehydrolysis to obtain the cellulosic material of prehydrolysis;
B) finish described prehydrolysis operation in ending phase;
C) make the cellulosic material lignification removal of described prehydrolysis in the boiling stage;
Wherein said ending phase comprises that at least once adding akaline liquid under first pressure also at least once reduces pressure subsequently.
The specific embodiment
According to the present invention,, preferably under about 160～170 ℃ temperature, live (open) steam is incorporated in the chip column of boiling vessel and in vapor phase, carries out the prehydrolysis stage by under about 150～180 ℃ temperature.Steam is introduced usually with low-pressure steam (LP; About 3.5 crust, 150 ℃) beginning, then with middle pressure steam (MP; About 10.5 crust, 200 ℃) continue, in blast pipe, obtain desired temperatures at boiling vessel, promptly the temperature of boiling vessel content is about 150～180 ℃.Temperature from blast pipe in the temperature survey boiling vessel of discharge gas.During the prehydrolysis stage, the pressure in the boiling vessel can cling between 10.0 crust 4.8 and change, and is preferably about 6 crust～about 9 crust.
The suitable prehydrolysis time is about 10～200 minutes, preferred about 20～120 minutes.
According to the present invention, after finishing the prehydrolysis stage, the content neutralization with boiling vessel promptly finishes the prehydrolysis stage by ending phase, this ending phase comprises at least once adding akaline liquid under general pressure (i.e. first pressure), and at least once reducing pressure subsequently reaches second pressure.Therefore, according to the present invention, first pressure always is higher than second pressure.Pressure differential between first pressure and second pressure, i.e. the amplitude of pressure drop depends on the several processes variable, for example the intensity of alkali, boiling vessel pressure and compactedness.The pressure of boiling vessel reduces, thus the alkali of charging/introducing evaporation and thus in and the material of the prehydrolysis in the boiling vessel.This ending phase also can be called neutralization stage, because the material of acid prehydrolysis is neutralized during this step.Determine the inlet amount of alkali, make all liquid in the boiling vessel (free fluid that wood chip is outer and retain and be fixed on liquid in the wood chip) be neutralized, and to obtain pH be 7 or higher alkali condition.
According to one embodiment of the present invention, in ending phase, at first general pressure promptly under first pressure with the suitable akaline liquid of about 2～15% (based on the NaOH of timber), Jian Hua black liquor for example, preferably liquid in vain joins in the boiling vessel.Pressure when described first pressure finished for the prehydrolysis stage, promptly 4.8 crust～10.0 cling to, preferred about 6 crust～about 9 crust.Can't directly measure the pH of boiling vessel content, therefore being fed to boiling vessel by the akaline liquid with some additional quantity guarantees alkali condition usually.Secondly, after adding akaline liquid, the pressure of boiling vessel temporarily is reduced to about 2～7 crust, second pressure of preferred about 3～5 crust from first pressure.Described pressure reduces about 1 second～10 minutes, preferred 30 seconds～5 minutes.After temporary transient decompression, continue described method by alkaline lignification removal step.In lignification removal's step, boiling vessel is filled by the boiling chemicals, and temperature is elevated to boiling temperature, keeps this temperature until the lignification removal's degree that reaches expectation.
According to another embodiment of the invention, carry out the decompression operation of ending phase gradually.In this case, at first, under general pressure with the suitable akaline liquid of about 2～15% (based on the NaOH of timber), Jian Hua black liquor for example, preferably liquid in vain joins in the boiling vessel.After adding akaline liquid, reduce pressure step by step gradually, for example reduce by 0.5～2 Palestine and Israel at every turn and reach final about 2～7 crust, the pressure of preferred 3～5 crust.After finishing ending phase, boiling vessel is filled by the boiling chemicals, continues the preparation of paper pulp thus by alkaline lignification removal step.
According to an embodiment more of the present invention, with required suitable akaline liquid, Jian Hua black liquor for example, the total amount (2～15% NaOH based on timber) of preferred white liquid joins in the boiling vessel gradually, and makes pressure from before pressure minimizing after each the adding.For example, at first join half required akaline liquid in the boiling vessel and immediately pressure is reduced for example 0.5～1 crust after this, preferred 0.5～0.7 crust.Pressure reduces the suitable time, promptly about 1 second～10 minutes time, preferred 30 seconds～5 minutes time.After temporary transient pressure reduces, remaining akaline liquid is joined in the described boiling vessel, carry out the pressure drop second time subsequently.Also can surpass the amount that two batches of ground add required akaline liquid.Each akaline liquid that adds reduces pressure afterwards.Pressure can for example reduce gradually, and the pressure before the pressure ratio reduces by 0.5～1 crust after adding akaline liquid thereby make, preferred 0.5～0.7 crust.
Those skilled in the art can determine best termination condition and process based on the process variables of paying close attention to.
Neutralizer preferably is incorporated in the boiling vessel by the bottom of boiling vessel, but other possible mode also within the scope of the invention.
After ending phase, make the cellulosic material lignification removal of prehydrolysis by the sulphate cook method of routine.When this conventional kraft pulp boiling begins, for example white liquid of boiling chemicals and waste black liquor are fed in the boiling vessel.Then by live (open) steam or heat the content of this boiling vessel via the indirect of recirculation slurrying liquid in the heat exchanger.For hardwood, suitable boiling temperature is about 150 ℃～180 ℃, preferred about 150 ℃～165 ℃; For cork, suitable boiling temperature is about 155 ℃～170 ℃.After reaching lignification removal's degree of expectation, the content of boiling vessel is dumped in the discharge tank.
In the prior art, after finishing prehydrolysis, content to boiling vessel neutralizes, in other words, finish the prehydrolysis stage by circulation or displacement that the liquid phase N-process is promptly very consuming time, therefore, when finishing neutralization procedure, the process conditions on boiling vessel top are different from the process conditions of boiling vessel lower part fully.In the method according to the invention, compare, very rapidly carry out the end or the neutralization in prehydrolysis stage with the method for prior art.This produces many advantages, promptly in the boiling circulation, save time, cause the productive rate of every cubic metre of boiling vessel to improve, uniformity through the hemicellulose level of cooking of pulp is improved, the uniformity through the content of lignin of cooking of pulp is improved, viscosity through cooking of pulp improves, and better without the brightness of pulp of bleaching.
Claims (8)
1. in boiling vessel, prepare the method for the paper pulp of prehydrolysis, comprising by the cellulosic material that contains lignin:
A) in first vapor phase, under first pressure, make described cellulosic material prehydrolysis to obtain the cellulosic material of prehydrolysis;
B) finish described prehydrolysis operation in ending phase;
C) make the cellulosic material lignification removal of described prehydrolysis in the boiling stage;
It is characterized in that described ending phase comprises that at least once adding akaline liquid under first pressure also at least once reduces pressure subsequently.
2. the process of claim 1 wherein that described method is a batch processes.
3. claim 1 or 2 method, wherein said akaline liquid is white liquid.
4. each method in the aforementioned claim, wherein said ending phase comprise once the adding akaline liquid and second pressure that once reduces pressure subsequently under described first pressure.
5. the method for claim 4, wherein said first pressure are that about 6～9 crust and described second pressure are about 3～5 crust.
6. the method for claim 5, wherein said once decompression be with 1 second～10 minutes, preferred 30 seconds～5 minutes time.
7. claim 1 or 2 method, wherein said ending phase comprise and once add akaline liquid and decompression gradually subsequently.
8. the method for claim 7, wherein described first pressure from about 6～9 crust are undertaken by each decompression 0.5～2 crust to the decompression gradually of second pressure, obtain second pressure of about 3～5 crust.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FI20085425 | 2008-05-08 | ||
| FI20085425A FI20085425L (en) | 2008-05-08 | 2008-05-08 | Sulfate pre-hydrolysis cooking method |
| PCT/FI2009/050364 WO2009136000A1 (en) | 2008-05-08 | 2009-05-06 | Prehydrolysis sulfate cooking process |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN102016162A true CN102016162A (en) | 2011-04-13 |
Family
ID=39523080
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2009801162710A Pending CN102016162A (en) | 2008-05-08 | 2009-05-06 | Prehydrolysis sulfate cooking process |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US20110056637A1 (en) |
| EP (1) | EP2286022A1 (en) |
| CN (1) | CN102016162A (en) |
| FI (1) | FI20085425L (en) |
| WO (1) | WO2009136000A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102337693A (en) * | 2011-09-30 | 2012-02-01 | 重庆理文造纸有限公司 | Process for stewing and washing dissolving pulp |
| CN108252141A (en) * | 2018-01-04 | 2018-07-06 | 安徽工程大学 | A kind of preparation method of Lin's grass fiber and its wet laid nonwoven fabric |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2567022B1 (en) * | 2010-05-04 | 2014-10-15 | Bahia Specialty Cellulose SA | Method and system for pulp processing using cold caustic extraction with alkaline filtrate reuse |
| AU2010202496B2 (en) * | 2010-05-04 | 2015-04-16 | Bahia Specialty Cellulose Sa | Method and system for high alpha dissolving pulp production |
| KR20110123184A (en) | 2010-05-06 | 2011-11-14 | 바히아 스페셜티 셀룰로스 에스에이 | Method and system for producing high alpha dissolving pulp |
| RU2546497C1 (en) * | 2011-05-13 | 2015-04-10 | Вальмет Актиеболаг | Compact method of producing preliminarily hydrolysed cellulose |
| CA3003581C (en) * | 2016-02-16 | 2023-06-27 | Valmet Ab | Method for recovering concentrated hydrolysate after hydrolysis of cellulose material |
| EP3673110B1 (en) * | 2017-08-25 | 2025-03-26 | Valmet AB | Improved compact process for producing prehydrolyzed pulp |
| SE1950606A1 (en) * | 2019-05-22 | 2020-10-13 | Valmet Oy | A method for extracting hydrolysate, a batch cooking system and a hydrolysate extracting arrangement |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3013933A (en) * | 1953-01-28 | 1961-12-19 | Rayonier Inc | Method for preparation of wood cellulose |
| CN1094108A (en) * | 1992-12-02 | 1994-10-26 | 沃斯特-阿尔潘工业技术公司 | A kind of method of making dissolving pulp |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB758766A (en) * | 1954-05-10 | 1956-10-10 | Brown And Root Inc | Process for the production of pulp from bagasse |
| US5203963A (en) * | 1991-10-21 | 1993-04-20 | A. Ahlstrom Corporation | Continuous treatment of small chips |
| US5198074A (en) * | 1991-11-29 | 1993-03-30 | Companhia Industreas Brasileiras Portela | Process to produce a high quality paper product and an ethanol product from bamboo |
| SE523850E (en) * | 1997-09-22 | 2009-06-02 | Metso Fiber Ab | Procedure for the pre-treatment of chips with base steam and impregnation liquid |
| DE19856582C1 (en) * | 1998-12-08 | 2001-03-15 | Rhodia Acetow Ag | Process for the production of chemical pulp from wood chips |
| SE518738C2 (en) * | 2001-12-17 | 2002-11-12 | Kvaerner Pulping Tech | Wood chip impregnation method for chemical pulping, comprises impregnating chips with liquid in different temperature zones of vessel |
| EP1885864A4 (en) | 2005-06-03 | 2011-04-13 | Iogen Energy Corp | Method of continuous processing of lignocellulosic feedstocks |
| FI123036B (en) * | 2006-02-10 | 2012-10-15 | Metso Paper Inc | Process for collection of hydrolysis products |
-
2008
- 2008-05-08 FI FI20085425A patent/FI20085425L/en not_active Application Discontinuation
-
2009
- 2009-05-06 WO PCT/FI2009/050364 patent/WO2009136000A1/en active Application Filing
- 2009-05-06 US US12/991,554 patent/US20110056637A1/en not_active Abandoned
- 2009-05-06 EP EP09742200A patent/EP2286022A1/en not_active Withdrawn
- 2009-05-06 CN CN2009801162710A patent/CN102016162A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3013933A (en) * | 1953-01-28 | 1961-12-19 | Rayonier Inc | Method for preparation of wood cellulose |
| CN1094108A (en) * | 1992-12-02 | 1994-10-26 | 沃斯特-阿尔潘工业技术公司 | A kind of method of making dissolving pulp |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102337693A (en) * | 2011-09-30 | 2012-02-01 | 重庆理文造纸有限公司 | Process for stewing and washing dissolving pulp |
| CN102337693B (en) * | 2011-09-30 | 2014-01-22 | 重庆理文造纸有限公司 | Process for stewing and washing dissolving pulp |
| CN108252141A (en) * | 2018-01-04 | 2018-07-06 | 安徽工程大学 | A kind of preparation method of Lin's grass fiber and its wet laid nonwoven fabric |
Also Published As
| Publication number | Publication date |
|---|---|
| EP2286022A1 (en) | 2011-02-23 |
| FI20085425A0 (en) | 2008-05-08 |
| WO2009136000A1 (en) | 2009-11-12 |
| FI20085425A7 (en) | 2009-11-09 |
| FI20085425L (en) | 2009-11-09 |
| US20110056637A1 (en) | 2011-03-10 |
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Application publication date: 20110413 |