CA2390742C - Removal of water-soluble compounds from wood chips prior to cooking - Google Patents
Removal of water-soluble compounds from wood chips prior to cooking Download PDFInfo
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- CA2390742C CA2390742C CA002390742A CA2390742A CA2390742C CA 2390742 C CA2390742 C CA 2390742C CA 002390742 A CA002390742 A CA 002390742A CA 2390742 A CA2390742 A CA 2390742A CA 2390742 C CA2390742 C CA 2390742C
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- wood chips
- water
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- liquid
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- 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
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- Chemical And Physical Treatments For Wood And The Like (AREA)
Abstract
Processes and systems for the treatment of wood chips prior to cooking remove substantially (e.g., at least about 30%) water-soluble compounds therein, especially those compounds which disassociate in water to form potassium and/or chloride ions and/or water-soluble metal compounds such as manganese, calcium and potassium. In preferred embodiments, wood chips entering the cooking system containing water-soluble compounds, such as those compounds which disassociate in water to form potassium and/or chloride ions and/or water-soluble metal compounds such as manganese, calcium and potassium, may be treated prior to cooking by being brought into contact with an aqueous treatment stream (e.g., water or steam condensate) at a temperature (e.g., between about 20°C to about 120°C) and for a time (e.g., between about 2 to 200 minutes) so as to reduce substantially (e.g., at least about 30%) such water-soluble compounds.
Description
l hI ;I I
REMOVAL OF WATER-SOLUBLE COMPOUNDS FROM
WOOD CHIPS PRIOR TO COOKING
FIELD OF THE INVENTION
The present invention relates generally to the field of wood chip treatments. In especially preferred embodiments, the present invention relates to treatment of wood chips prior to cooking in a pulp manufacturing process.
BACKGROUND AND SUMMARY OF THE INVENTION
The presence of some water-soluble compounds can have 1o deleterious effects in pulping processes. For example, compounds which disassociate in water to form potassium and/or chloride ions, lower the melting point of fly ash in the recovery boiler of a wood pulp mill. This reduced melting point of the fly ash in turn requires that the recovery boiler be operated at a lower temperature, thereby reducing the efficiency of the boiler. To overcome this problem, it is highly desirable that water-soluble compounds be removed from wood chips prior to being cooked.
Similarly, water soluble metal compounds such as manganese, calcium, potassium and the like should be removed prior to cooking of wood chips so as to ensure that the resulting pulp may be more easily bleached.
In this regard, manganese is especially harmful to the bleaching process and is known to cause poor bleaching results. Moreover, the removal of calcium results in reduced scaling in the digester and evaporators.
Broadly, the present invention is embodied in processes whereby wood chips are treated prior to cooking so as to remove substantially (e.g., at least about 30 wt.%, more preferably at least about 50 wt.% and most preferably at least 70 wt.%) water-soluble compounds, especially those compounds which disassociate in water to form potassium and/or chloride ions.
REMOVAL OF WATER-SOLUBLE COMPOUNDS FROM
WOOD CHIPS PRIOR TO COOKING
FIELD OF THE INVENTION
The present invention relates generally to the field of wood chip treatments. In especially preferred embodiments, the present invention relates to treatment of wood chips prior to cooking in a pulp manufacturing process.
BACKGROUND AND SUMMARY OF THE INVENTION
The presence of some water-soluble compounds can have 1o deleterious effects in pulping processes. For example, compounds which disassociate in water to form potassium and/or chloride ions, lower the melting point of fly ash in the recovery boiler of a wood pulp mill. This reduced melting point of the fly ash in turn requires that the recovery boiler be operated at a lower temperature, thereby reducing the efficiency of the boiler. To overcome this problem, it is highly desirable that water-soluble compounds be removed from wood chips prior to being cooked.
Similarly, water soluble metal compounds such as manganese, calcium, potassium and the like should be removed prior to cooking of wood chips so as to ensure that the resulting pulp may be more easily bleached.
In this regard, manganese is especially harmful to the bleaching process and is known to cause poor bleaching results. Moreover, the removal of calcium results in reduced scaling in the digester and evaporators.
Broadly, the present invention is embodied in processes whereby wood chips are treated prior to cooking so as to remove substantially (e.g., at least about 30 wt.%, more preferably at least about 50 wt.% and most preferably at least 70 wt.%) water-soluble compounds, especially those compounds which disassociate in water to form potassium and/or chloride ions.
More specifically, as described briefly above, wood chips entering the cooking system contain water-soluble compounds, such as those compounds which disassociate in water to form potassium and/or chloride ions. According to the present invention, wood chips are treated prior to cooking by being brought into contact with an aqueous treatment stream (e.g., water or steam condensate) so as to reduce substantially (e.g., at least about 30 wt.%) such potassium- or chloride-containing water-soluble compounds. By treatment of the wood chips in accordance with the present invention, water-soluble compounds, specifically potassium- or chloride-1o containing water-soluble compounds, present in the wood chips are displaced from the interior of the chips and accumulate in the aqueous treatment liquid present. The aqueous treatment liquid containing the water-soluble compounds may then be drained from the chips prior to the chips entering the cooking system. These wood chips can be treated (washed) multiple times so as to sequentially increase the amount of water-soluble compounds, specifically potassium- and/or chloride-containing compounds, removed therefrom.
These and other aspects and advantages will become more apparent after careful consideration is given to the following detailed description of the preferred exemplary embodiments thereof.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Reference will hereinafter be made to the accompanying drawings, wherein like reference numerals throughout the various FIGURES denote like structural elements, and wherein;
FIGURES 1-3 each represent a schematic view of a possible wood chip treatment technique in accordance with the present invention;
FIGURES 4A and 4B are graphical plots in accordance with the Examples below of potassium and chloride ion concentrations (mg/L) in chip i6 s 1' 1 il i I
These and other aspects and advantages will become more apparent after careful consideration is given to the following detailed description of the preferred exemplary embodiments thereof.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Reference will hereinafter be made to the accompanying drawings, wherein like reference numerals throughout the various FIGURES denote like structural elements, and wherein;
FIGURES 1-3 each represent a schematic view of a possible wood chip treatment technique in accordance with the present invention;
FIGURES 4A and 4B are graphical plots in accordance with the Examples below of potassium and chloride ion concentrations (mg/L) in chip i6 s 1' 1 il i I
filtrate versus leach time for 2-3 mm unsteamed and steamed wood chips, respectively;
FIGURES 5A and 5B are graphical plots in accordance with the Examples below of potassium and chloride ion concentrations (mg/L) in chip filtrate versus leach time for 4-6 mm unsteamed and steamed wood chips, respectively;
FIGURES 6A and 6B are graphical plots in accordance with the Examples below of potassium and chloride ion concentrations (mg/L) in chip filtrate versus leach time for 8-10 mm unsteamed and steamed wood chips, lo respectively; and FIGURE 7 is plot of the percentage of total potassium removed from three different wood chip size categories in accordance with the Examples below.
DETAILED DESCRIPTION OF THE INVENTION
The aqueous wash stream that may be employed in the practice of the present invention can be virtually any stream which is capable of being processed in the pulp mill's existing wastewater treatment system. Such streams include, but are not limited to, water, evaporator (and/or other mill) condensates, collected rainwater, and bleach plant effluent. The wash may 2o advantageously be carried out at temperatures between about 20 C to about 120 C (e.g., advantageously between about 30 C to about 90 C), at pressures up to the operating pressure of the downstream digester. The residence time in which the wood chips may be in contact with the aqueous wash liquid can be from about 2 to about 200 minutes. The wash is most preferably conducted at a pH of between about 2 to about 12, and more preferably between about 4 to about 10. It is especially preferred that the wash be conducted at elevated pressures which, as noted above, can be up to the pressure condition of the downstream digester.
FIGURES 5A and 5B are graphical plots in accordance with the Examples below of potassium and chloride ion concentrations (mg/L) in chip filtrate versus leach time for 4-6 mm unsteamed and steamed wood chips, respectively;
FIGURES 6A and 6B are graphical plots in accordance with the Examples below of potassium and chloride ion concentrations (mg/L) in chip filtrate versus leach time for 8-10 mm unsteamed and steamed wood chips, lo respectively; and FIGURE 7 is plot of the percentage of total potassium removed from three different wood chip size categories in accordance with the Examples below.
DETAILED DESCRIPTION OF THE INVENTION
The aqueous wash stream that may be employed in the practice of the present invention can be virtually any stream which is capable of being processed in the pulp mill's existing wastewater treatment system. Such streams include, but are not limited to, water, evaporator (and/or other mill) condensates, collected rainwater, and bleach plant effluent. The wash may 2o advantageously be carried out at temperatures between about 20 C to about 120 C (e.g., advantageously between about 30 C to about 90 C), at pressures up to the operating pressure of the downstream digester. The residence time in which the wood chips may be in contact with the aqueous wash liquid can be from about 2 to about 200 minutes. The wash is most preferably conducted at a pH of between about 2 to about 12, and more preferably between about 4 to about 10. It is especially preferred that the wash be conducted at elevated pressures which, as noted above, can be up to the pressure condition of the downstream digester.
Various techniques may be employed in accordance with the present invention. For example, as shown in accompanying FIGURE 1, one system includes a chip bin 12, such as disclosed in U.S. Patent No. 5,500,083 and available commercially from Andritz Inc. of Glens Falls, New York as 5 DiamondbackO Steaming Vessel. Steam may be injected into the wood chips contained within the chip bin 12 via line 12-1. The chip bin 12 is provided with a meter screw 14, such that condensate is capable of being drained therefrom via line 16. Such drained condensate may then be sent to the pulp mill's existing wastewater treatment system (not shown). The chip bin 12 shown in 10 FIGURE 1 could, if desired, be provided without steaming, but with a meter screw and a horizontally or vertically disposed wash vessel (not shown) downstream of the meter screw where wash liquid may be introduced. The wash effluent may thus be drained from the wash vessel and processed in the pulp mill's existing wastewater treatment system.
The system 20 shown in FIGURE 2 includes a similar chip bin 12 as depicted in FIGURE 1, in that it is steam may be injected into the wood chips contained therein by line 22-1 and that it is provided with a meter screw 24.
In addition, the chip bin 22 is provided with a plurality of serially arranged horizontally or vertically disposed wash vessels 25, 26 downstream thereof where wash liquid may be introduced. The chips may be washed with water or other suitable aqueous stream via line 27. The liquid may be drained from an initial one of the wash vessels 25 via line 25-1 and then directed to a second downstream wash vessel 26 where the chips are washed a second time. Liquid drained from the second wash vessel may be divided into respective portions, with one portion thereof being employed as wastewater treatment via line 26-1, and another portion thereof used to flow counter-current via line 26-2 with the wood chips in the first wash vessel 25. Thus, with the series of wash vessels 25, 26 as depicted in FIGURE 2, each one has the ability to gather the drained wash liquid and return it to the preceding wash vessel or be sent to the pulp mill's existing wastewater treatment system.
The last wash vessel in the series could be, for example, an in-line separator, while an intermediate wash vessel could be a retention vessel to increase the retention time of wash material in contact with wood chips. Such a system 30 is depicted in the embodiment depicted in accompanying FIGURE 3. Alternatively, instead of a dedicated wash vessel, the final chip wash could occur physically in the top-separator of the digester.
More specifically, as shown in FIGURE 3, the chip bin 32 includes a meter screw 34 and is provided with a line 32-1 to allow steam injection into the wood chips contained therein. A series of wash vessels 35, 36 and 37 are provided to allow the wood chips to be sequentially washed in countercurrent fashion via fresh wash water supplied via lines 39-1, 39-2 and 39-3, respectively. As noted briefly above, the last wash vessel 37 in the series could be, for example, an in-line separator. A retention vessel 40 is preferably interposed in the chip flow between the initial was vessel 35 and the intermediate wash vessel 36. The retention vessel serves to increase the retention time of wash material in contact with wood chips. The liquid may be drained from wash vessel 35 via line 35-1.
Liquid drained from the intermediate and final wash vessels 36, 37 may be divided into respective portions, with one portion thereof being employed as wastewater treatment via lines 36-1 and 37-1, respectively, and another portion thereof used to flow counter-current via lines 36-2 and 37-2 with the wood chips in the first and intermediate wash vessels 35 and 36, respectively.
Thus, as was the case with the series of wash vessels 25, 26 as depicted in FIGURE 2, the wash vessels 36, 37 in the system 30 shown in FIGURE 3 has the ability to gather the drained wash liquid and return it to the preceding wash vessel or be sent to the pulp mill's existing wastewater treatment system.
It has been found that the removal of water-soluble compounds can be accomplished. In one specific embodiment of the invention, it has been k ~~ ~ I il I
The system 20 shown in FIGURE 2 includes a similar chip bin 12 as depicted in FIGURE 1, in that it is steam may be injected into the wood chips contained therein by line 22-1 and that it is provided with a meter screw 24.
In addition, the chip bin 22 is provided with a plurality of serially arranged horizontally or vertically disposed wash vessels 25, 26 downstream thereof where wash liquid may be introduced. The chips may be washed with water or other suitable aqueous stream via line 27. The liquid may be drained from an initial one of the wash vessels 25 via line 25-1 and then directed to a second downstream wash vessel 26 where the chips are washed a second time. Liquid drained from the second wash vessel may be divided into respective portions, with one portion thereof being employed as wastewater treatment via line 26-1, and another portion thereof used to flow counter-current via line 26-2 with the wood chips in the first wash vessel 25. Thus, with the series of wash vessels 25, 26 as depicted in FIGURE 2, each one has the ability to gather the drained wash liquid and return it to the preceding wash vessel or be sent to the pulp mill's existing wastewater treatment system.
The last wash vessel in the series could be, for example, an in-line separator, while an intermediate wash vessel could be a retention vessel to increase the retention time of wash material in contact with wood chips. Such a system 30 is depicted in the embodiment depicted in accompanying FIGURE 3. Alternatively, instead of a dedicated wash vessel, the final chip wash could occur physically in the top-separator of the digester.
More specifically, as shown in FIGURE 3, the chip bin 32 includes a meter screw 34 and is provided with a line 32-1 to allow steam injection into the wood chips contained therein. A series of wash vessels 35, 36 and 37 are provided to allow the wood chips to be sequentially washed in countercurrent fashion via fresh wash water supplied via lines 39-1, 39-2 and 39-3, respectively. As noted briefly above, the last wash vessel 37 in the series could be, for example, an in-line separator. A retention vessel 40 is preferably interposed in the chip flow between the initial was vessel 35 and the intermediate wash vessel 36. The retention vessel serves to increase the retention time of wash material in contact with wood chips. The liquid may be drained from wash vessel 35 via line 35-1.
Liquid drained from the intermediate and final wash vessels 36, 37 may be divided into respective portions, with one portion thereof being employed as wastewater treatment via lines 36-1 and 37-1, respectively, and another portion thereof used to flow counter-current via lines 36-2 and 37-2 with the wood chips in the first and intermediate wash vessels 35 and 36, respectively.
Thus, as was the case with the series of wash vessels 25, 26 as depicted in FIGURE 2, the wash vessels 36, 37 in the system 30 shown in FIGURE 3 has the ability to gather the drained wash liquid and return it to the preceding wash vessel or be sent to the pulp mill's existing wastewater treatment system.
It has been found that the removal of water-soluble compounds can be accomplished. In one specific embodiment of the invention, it has been k ~~ ~ I il I
found that water-soluble potassium can be removed from wood chips. More specifically, in laboratory experiments carried out at atmospheric pressure and at temperatures ranging from 30 C to 90 C with wash liquid contact time of about 30 minutes, potassium-containing compounds may be reduced substantially in an amount of at least about 30 wt.% (e.g., between about 30 wt.% to about 40 wt.%). The operational conditions used in the laboratory experiments were selected due to the practical limitations existing in the laboratory and are thus non-limiting to the present invention. That is, other operational conditions may be employed within the context of the 1o present invention. Based on the results of the laboratory experiments, it is expected that potassium removal will increase at higher temperatures and/or operating pressures. It is also expected that the commercial operating conditions will be different from those used in the laboratory, specifically higher temperature, higher pressure and longer retention time.
The present invention will be further understood from the following non-limiting Examples.
EXAMPLES
Wood chips were tested for moisture content before any treatment was performed. Chips were separated into two portions - that is, one portion for those chips to be pre-treated with steam prior to the leaching treatment and another portion for those chips to be treated only by the leaching treatment (i.e., without any steam pre-treatment). The condensate formed during the steaming treatment was drained and tested for potassium content. Chips to be pre-treated with steam were segregated into three different chip size categories - that is, chips having a size, on average, of 3 mm, 4-6 mm and 8-10 mm, respectively. Numerous bags containing 50g of wood chips for each chip size category were prepared. Respective bags of wood chips were then subjected to each of three different temperature regimes (i.e., 30 C, 60 C and 90 C) and five different retention time regimes (i.e., 1 min., 2 min., 5 min., 10 min. and 30 min.). A total of 45 bags of chips was prepared for the steamed wood chips. The same procedures as described above were also followed for preparation of wood chip-containing bags for the non-steam pre-treated chips.
A container of water was heated to the desired temperature (i.e., 30 C, 60 C and 90 C). Once at temperature, a bag of chips was introduced and held at temperature for the desired retention time. After reaching the desired retention time, the heating was terminated and the filtrate tested for chloride and potassium content. Standard Method 4500 (Standard Methods, 18th Ed., Meruric Nitrate Method 4500-Cl, Section C, 1992) was 1o used for chlorides and Standard Method 3111 was used for potassium (Standard Methods, 18th Ed., Metals by Flame Atomic Absorption Spectrometry 3111 A & B, 1992) The concentrations of potassium and chloride present in the filtrate versus the leach time were plotted for each of the unsteamed and steamed wood chips size categories and appears as FIGURES 4A-4B, 5A-5B and 6A-6B, respectively.
The percentage of potassium removed by steaming and leaching was also calculated and such data appear in FIGURE 7.
,~**** ****** ** *** ***,~**
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
The present invention will be further understood from the following non-limiting Examples.
EXAMPLES
Wood chips were tested for moisture content before any treatment was performed. Chips were separated into two portions - that is, one portion for those chips to be pre-treated with steam prior to the leaching treatment and another portion for those chips to be treated only by the leaching treatment (i.e., without any steam pre-treatment). The condensate formed during the steaming treatment was drained and tested for potassium content. Chips to be pre-treated with steam were segregated into three different chip size categories - that is, chips having a size, on average, of 3 mm, 4-6 mm and 8-10 mm, respectively. Numerous bags containing 50g of wood chips for each chip size category were prepared. Respective bags of wood chips were then subjected to each of three different temperature regimes (i.e., 30 C, 60 C and 90 C) and five different retention time regimes (i.e., 1 min., 2 min., 5 min., 10 min. and 30 min.). A total of 45 bags of chips was prepared for the steamed wood chips. The same procedures as described above were also followed for preparation of wood chip-containing bags for the non-steam pre-treated chips.
A container of water was heated to the desired temperature (i.e., 30 C, 60 C and 90 C). Once at temperature, a bag of chips was introduced and held at temperature for the desired retention time. After reaching the desired retention time, the heating was terminated and the filtrate tested for chloride and potassium content. Standard Method 4500 (Standard Methods, 18th Ed., Meruric Nitrate Method 4500-Cl, Section C, 1992) was 1o used for chlorides and Standard Method 3111 was used for potassium (Standard Methods, 18th Ed., Metals by Flame Atomic Absorption Spectrometry 3111 A & B, 1992) The concentrations of potassium and chloride present in the filtrate versus the leach time were plotted for each of the unsteamed and steamed wood chips size categories and appears as FIGURES 4A-4B, 5A-5B and 6A-6B, respectively.
The percentage of potassium removed by steaming and leaching was also calculated and such data appear in FIGURE 7.
,~**** ****** ** *** ***,~**
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
Claims (7)
1. A process for treating wood chips prior to the chips being cooked under elevated temperature and pressure conditions in a downstream digester, the process comprising the sequential steps of:
(a) providing a chip bin upstream of the digester;
(b) introducing a supply of untreated wood chips containing water-soluble potassium-containing and/or chloride-containing compounds into the chip bin;
(c) injecting steam into the supply of untreated wood chips in the chip bin to thereby form a mass of wood chips and condensate as an aqueous treatment liquid;
(d) transferring the mass of wood chips and condensate to downstream wash vessels and introducing into the wash vessels an aqueous wash liquid therein as additional aqueous treatment liquid;
(e) maintaining the aqueous treatment liquid of step (d) in contact with the wood chips at an elevated pressure not exceeding the pressure of the digester and at a temperature between about 30°C to about 90°C, a pH of between about 4 to and for a time between 2 to about 200 minutes sufficient to reduce substantially water soluble potassium-containing and/or chloride-containing compounds therein by at least 30 wt.% to thereby form a supply of treated wood chips in a waste treatment liquid containing the removed water soluble compounds;
(f) separating the treated wood chips from the waste treatment liquid; and (g) supplying the treated wood chips to the downstream digester;
wherein step (d) comprises washing the treated wood chips in a sequential series of wash vessels disposed between the chip bin and the downstream digester, and washing the treated wood chips in a countercurrent system by feeding washing liquid as a countercurrent flow relative to the direction of flow of the wood chips, liquid being withdrawn from a downstream washing vessel being recirculated to an upstream washing vessel.
(a) providing a chip bin upstream of the digester;
(b) introducing a supply of untreated wood chips containing water-soluble potassium-containing and/or chloride-containing compounds into the chip bin;
(c) injecting steam into the supply of untreated wood chips in the chip bin to thereby form a mass of wood chips and condensate as an aqueous treatment liquid;
(d) transferring the mass of wood chips and condensate to downstream wash vessels and introducing into the wash vessels an aqueous wash liquid therein as additional aqueous treatment liquid;
(e) maintaining the aqueous treatment liquid of step (d) in contact with the wood chips at an elevated pressure not exceeding the pressure of the digester and at a temperature between about 30°C to about 90°C, a pH of between about 4 to and for a time between 2 to about 200 minutes sufficient to reduce substantially water soluble potassium-containing and/or chloride-containing compounds therein by at least 30 wt.% to thereby form a supply of treated wood chips in a waste treatment liquid containing the removed water soluble compounds;
(f) separating the treated wood chips from the waste treatment liquid; and (g) supplying the treated wood chips to the downstream digester;
wherein step (d) comprises washing the treated wood chips in a sequential series of wash vessels disposed between the chip bin and the downstream digester, and washing the treated wood chips in a countercurrent system by feeding washing liquid as a countercurrent flow relative to the direction of flow of the wood chips, liquid being withdrawn from a downstream washing vessel being recirculated to an upstream washing vessel.
2. The process of claim 1, wherein step (e) is practiced so as to reduce said water soluble compounds by an amount of at least about 50 wt.%.
3. The process of claim 2, wherein step (e) is practiced so as to reduce said water soluble compounds by an amount of at least about 70 wt.%.
4. The process of any one of claims 1-3 wherein step (d) is practiced using said wash liquid which is at least one selected from the group consisting of hot water, bleach plant filtrates, collected rain water, evaporator condensate and other mill condensates.
5. The process of any one of claims 1-4, wherein an in-line separator is used as the last washing vessel.
6. The process of any one of claims 1-5, wherein during washing an intermediate retention vessel is used for increasing the time of contact between washing liquid and the wood chips.
7. The process of claim 6, comprising the use of said retention vessel after a first washing vessel and a following washing vessel.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US29977001P | 2001-06-22 | 2001-06-22 | |
| US60/299,770 | 2001-06-22 | ||
| US10/159,292 | 2002-06-03 | ||
| US10/159,292 US20030000661A1 (en) | 2001-06-22 | 2002-06-03 | Removal of water-soluble compounds from wood chips prior to cooking |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2390742A1 CA2390742A1 (en) | 2002-12-22 |
| CA2390742C true CA2390742C (en) | 2009-11-10 |
Family
ID=26855812
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002390742A Expired - Fee Related CA2390742C (en) | 2001-06-22 | 2002-06-17 | Removal of water-soluble compounds from wood chips prior to cooking |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US20030000661A1 (en) |
| JP (1) | JP2003020582A (en) |
| CA (1) | CA2390742C (en) |
| FI (1) | FI20021152A (en) |
| SE (1) | SE528163C2 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7309401B2 (en) | 2003-05-12 | 2007-12-18 | Andritz Inc. | Top separator for gas phase and hydraulic phase continuous digesters and method for converting digester |
| EP1561536A1 (en) * | 2004-02-03 | 2005-08-10 | Siemens Aktiengesellschaft | Process of brazing repairing of a part having a base material with oriented microstructure |
| FI122651B (en) * | 2004-11-19 | 2012-05-15 | Metso Paper Inc | Process and apparatus for treating wood chips |
| US20150376834A1 (en) * | 2013-02-07 | 2015-12-31 | University Of Maine System Board Of Trustees | Extraction of lignocellulosics for production of fibers and a precipitate-free hemicellulose extract |
| BR112016014206A2 (en) * | 2013-12-18 | 2017-08-08 | Shell Int Research | CONTINUOUS OR SEMI-CONTINUOUS BIOMASS WASHING SYSTEM FOR HYDROTHERMIC HYDROCATALYTIC COVERSION |
| SE542430C2 (en) * | 2017-09-19 | 2020-04-28 | Domsjoe Fabriker Ab | Removal of inorganic elements from wood chips |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FI58360C (en) * | 1974-06-14 | 1981-01-12 | Mo Och Domsjoe Ab | FOERFARANDE FOER DELIGNIFIERING AV LIGNOCELLULOSAHALTIGT MATERIAL MED HJAELP AV SYREINNEHAOLLANDE GAS OCH APPARATUR FOER UTFOERANDE AV DETTA FOERFARANDE |
| SE416481B (en) * | 1977-05-02 | 1981-01-05 | Mo Och Domsjoe Ab | METHOD AND DEVICE FOR TREATMENT OF WOOD TIP FOR REMOVAL OF HEAVY METALS AND RESIN |
| US4826567A (en) * | 1985-08-05 | 1989-05-02 | Interox (Societe Anonyme) | Process for the delignification of cellulosic substances by pretreating with a complexing agent followed by hydrogen peroxide |
| FI81396C (en) * | 1988-10-25 | 1990-10-10 | Enso Gutzeit Oy | FOERFARANDE FOER BEHANDLING AV AVFALLSVATTEN FRAON TRAEFOERAEDLINGSINDUSTRINS MASSAFRAMSTAELLNINGSPROCESSER. |
| US6143134A (en) * | 1998-11-06 | 2000-11-07 | Andritz-Ahlstrom Inc. | Chip spreader for air-lock feeder |
-
2002
- 2002-06-03 US US10/159,292 patent/US20030000661A1/en not_active Abandoned
- 2002-06-14 FI FI20021152A patent/FI20021152A/en not_active Application Discontinuation
- 2002-06-14 JP JP2002174678A patent/JP2003020582A/en active Pending
- 2002-06-17 CA CA002390742A patent/CA2390742C/en not_active Expired - Fee Related
- 2002-06-20 SE SE0201891A patent/SE528163C2/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| SE0201891L (en) | 2002-12-23 |
| CA2390742A1 (en) | 2002-12-22 |
| FI20021152A (en) | 2002-12-23 |
| SE0201891D0 (en) | 2002-06-20 |
| US20030000661A1 (en) | 2003-01-02 |
| FI20021152A0 (en) | 2002-06-14 |
| SE528163C2 (en) | 2006-09-19 |
| JP2003020582A (en) | 2003-01-24 |
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