WO1994011566A1 - Process for continuous cooking of pulp - Google Patents
Process for continuous cooking of pulp Download PDFInfo
- Publication number
- WO1994011566A1 WO1994011566A1 PCT/SE1993/000816 SE9300816W WO9411566A1 WO 1994011566 A1 WO1994011566 A1 WO 1994011566A1 SE 9300816 W SE9300816 W SE 9300816W WO 9411566 A1 WO9411566 A1 WO 9411566A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- digester
- strainer
- cooking
- girdle
- strainer girdle
- Prior art date
Links
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
- D21C3/00—Pulping cellulose-containing materials
- D21C3/22—Other features of pulping processes
- D21C3/24—Continuous 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
- D21C7/00—Digesters
-
- 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
- D21C7/14—Means for circulating the lye
Definitions
- This invention relates to a method for continuous cooking of pulp, which method improves pulp quality so that sub ⁇ sequently none chlorine containing bleaching processes can be used in order to reach full brightness for a pulp having desired strength and quality properties.
- the pulp industry is therefore searching for methods which allow bleaching of pulp without using these chemi ⁇ cals.
- the lignox method (see SE-A 8902058) , in which, inter alia, bleaching is carried out with hydrogen peroxide, may be mentioned as an example of such a method.
- Ozone is another interesting bleaching chemical which is also gaining increased application. It is thus possible, using bleaching chemicals of this nature, to achieve those brightnesses which are required for market ⁇ able pulp, i.e. 89 ISO and greater, without using chlo ⁇ rine containing bleaching agents.
- the invention mainly relates to a method for achieving a cooking according to the new process, but also to a pre ⁇ ferred arrangement for achieving a cooking according to the invention in particular with regard to digesters built according to an older principle and consisting of an upper concurrent cooking zone and a lower counter- current washing zone.
- Such an arrangement is necessary since certain practical problems arise as a consequence of an isothermal cooking process.
- the first such problem is the difficulty of efficiently reaching and maintaining the temperature in the lower part of the digester, i.e. that part which is normally employed for washing.
- the said problem is solved by creating a more efficient circulation and thus temperature distribution in the lower part (the high-heat or washing zone) of the digester.
- digester strainer girdle consisting of oval or circu ⁇ lar strainers, in particular so-called manhole strainers, in connection with converting existing digesters, both of the modified type and the older type, for operation according to the new process.
- Figure sheet 1 a comparison is made in three diagrams between isothermal cooking and so-called modified conven ⁇ tional cooking (MCC) .
- Figure sheet 2 shows a diagram which describes degree of delignification and viscosity (the viscosity is normally regarded as indicating the strength properties of the pulp)
- Figure 3 shows how, in a preferred manner, an existing digester can be con ⁇ verted, using manhole strainers, to be operated according to the novel process.
- the first figure page shows three diagrams which compare different results obtained with isothermal cooking and conventional modified cooking (MCC) .
- MCC conventional modified cooking
- Figure 2 additionally demonstrates that, using the method according to the invention, very low kappa numbers are reached while at the same time retaining good pulp strength (viscosity round about 1000) after oxygen delig- nification.
- so-called environmentally friendly bleach ⁇ ing chemicals such as peroxide and ozone, can be employed in subsequent bleaching stages without risking too low a strength for bleaching up to the level of brightness, and therewith also the level of purity, which the market demands.
- Figure 3 shows the lower part of a digester 1, which is intended to represent an existing digester shell (which definitely is higher than 20 metres normally higher than 30 metres and usually about 40 metres and more and having a diameter of 1/10 of the height)on which has been arranged a new digester strainer girdle 2 in order to be able to raise the temperature in the counter-current zone.
- the digester has a lowest strainer girdle (IB) and one strainer girdle (ID) for withdrawal of spent liquor and is of the type which has an upper concurrent part and a lower counter-current part.
- IB strainer girdle
- ID strainer girdle
- the temperature is about 135°C on a level with the lower strainer.
- the counter-current zone of the digester which has been fitted with a further strainer girdle will be referred to as a cooking zone, even if it is to be considered as a washing zone according to con ⁇ ventional operation.
- the new digester strainer girdle 2 consists of a number of so-called manhole strainers 2A for withdrawal 3 of cooking liquid in the lower part of the digester and is arranged immediately above the lower strainer girdle IB, preferably at most 5 metres above more preferred 1,5 metres above and more preferably at most 1 metre above, measured from the upper edge of the lower digester strainer girdle to the lower edge of the newly fitted digester strainer girdle.
- Wash liquor is supplied to the lower part of the digester through an inflow arrangement 4 attached in the vicinity of the bottom 1A of the digester and cooking liquid (alkali addition) through the central pipes 5A, 5B.
- the cooked pulp is taken out from the bottom of the digester via a conduit IE.
- each strainer element 2A is made rela ⁇ tively small, preferably less than 0.3 2 .
- the new strainer girdle 2 is preferably fitted with ring pipes 2C from which an individual conduit goes to each and every one of the strainer elements 2A.
- a limited number (for example 4) of strainer units 2A can be efficiently back-flushed at a time. Owing to the rela ⁇ tively small total strainer surface which is back-flushed under these circumstances (for example 1 2 ) , a very ef ⁇ ficient back-flushing which cleans the strainers is obtained, thereby ensuring that the circulation is highly efficient.
- the invention is not limited by that which has been de- scribed above, but can be varied within the scope of the subsequent patent claims.
- an existing digester of the MCC type can also be arranged in accordance with the invention, where, therefore, the digester has an upper concurrent part, a central, mainly counter-current, part and a lower counter-current part, where addition of a part of the cooking liquid takes place in the said lower counter-current part, the so-called high-heat zone.
- a digester of the so-called hydraulic type with a lower temperature in the upper part (the impregnation zone) , may also advantageously be fitted with a digester strainer girdle according to the invention for cooking according to the invention, so-called isother ally.
- the method may be used in connection with all types of cooking liquid, even if the method is princi ⁇ pally intended for producing sulphate pulp.
- the invention is not limited to the above mentioned exempli ⁇ fying temperature levels.
- the average temperature level in the digester preferably exceeds +150°C but is lower than +165°C, and preferably is between 150-155°C for hardwood and between 160-165°C for softwood, and furthermore that the average temperature in the cooking zone/zones is preferably about +151°C +-1°C, when the wood is hard ⁇ wood, and that the average temperature in a digester is +159°C +-1°C, when the wood is softwood.
- strainers deviating from a circular form, for example oval strainers, or even rectangular may also be used, whereby, for technical reasons related to the construction, the smallest radius of curvature should preferably not fall below 0.2 m.
- strainer girdles can naturally also be fitted with strainer girdles, and be operated, according to the invention.
- more than one strainer girdle can be arranged between the strainer girdle withdrawing spent cooking liquor and the lowest strainer girdle. It is also evident for the skilled man that more than one strainer girdle may be used for withdrawing spent liquor.
- This lowest strainer girdle is normally positioned within its lower edge about 1-2 metres above the welded seam that joins the spherical bottom position with the cylindrical digester shell, but in extreme designs the distance might be as short as 0.5 metres and as long as 5 metres.
Abstract
Description
Claims
Priority Applications (10)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP93924847A EP0673453B1 (en) | 1992-11-18 | 1993-10-08 | Process for continuous cooking of pulp |
CA002149423A CA2149423C (en) | 1992-11-18 | 1993-10-08 | Process for continuous cooking of pulp |
RU95112468A RU2126470C1 (en) | 1992-11-18 | 1993-10-08 | Method for continuous digestion of fibrous material |
JP51197194A JP3223285B2 (en) | 1992-11-18 | 1993-10-08 | Continuous cooking of pulp |
DE69317670T DE69317670T2 (en) | 1992-11-18 | 1993-10-08 | METHOD FOR CONTINUOUSLY UNLOCKING CELLULAR |
DE0673453T DE673453T1 (en) | 1992-11-18 | 1993-10-08 | METHOD FOR CONTINUOUSLY UNLOCKING CELLULAR. |
BR9307480A BR9307480A (en) | 1992-11-18 | 1993-10-08 | Process for continuous cooking |
AU54355/94A AU673392B2 (en) | 1992-11-18 | 1993-10-08 | Process for continuous cooking of pulp |
FI952389A FI114718B (en) | 1992-11-18 | 1995-05-17 | Procedure for continuous boiling of pulp |
NO951972A NO306477B1 (en) | 1992-11-18 | 1995-05-18 | Process for continuous cooking of pulp |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE9203462A SE500455C2 (en) | 1992-11-18 | 1992-11-18 | Method of continuous cooking under elevated pressure and temperature of fiber material in a vertical digester |
SE9203462-8 | 1992-11-18 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1994011566A1 true WO1994011566A1 (en) | 1994-05-26 |
Family
ID=20387855
Family Applications (3)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/SE1993/000223 WO1994011564A1 (en) | 1992-11-18 | 1993-03-16 | Digester for continuous cooking of fibre material |
PCT/SE1993/000311 WO1994011565A1 (en) | 1992-11-18 | 1993-04-08 | Digester for continuous cooking of fibre material |
PCT/SE1993/000816 WO1994011566A1 (en) | 1992-11-18 | 1993-10-08 | Process for continuous cooking of pulp |
Family Applications Before (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/SE1993/000223 WO1994011564A1 (en) | 1992-11-18 | 1993-03-16 | Digester for continuous cooking of fibre material |
PCT/SE1993/000311 WO1994011565A1 (en) | 1992-11-18 | 1993-04-08 | Digester for continuous cooking of fibre material |
Country Status (18)
Country | Link |
---|---|
US (4) | US5470437A (en) |
EP (3) | EP0669998B2 (en) |
JP (3) | JP3287848B2 (en) |
CN (1) | CN1036728C (en) |
AT (3) | ATE156538T1 (en) |
AU (3) | AU684759B2 (en) |
BR (3) | BR9307478A (en) |
CA (3) | CA2149535C (en) |
DE (4) | DE69312955T3 (en) |
ES (3) | ES2105269T5 (en) |
FI (3) | FI113186B (en) |
MA (1) | MA23034A1 (en) |
NO (3) | NO306478B1 (en) |
NZ (3) | NZ252758A (en) |
RU (3) | RU2121537C1 (en) |
SE (3) | SE500455C2 (en) |
WO (3) | WO1994011564A1 (en) |
ZA (3) | ZA937958B (en) |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AU669274B2 (en) * | 1993-02-16 | 1996-05-30 | Kvaerner Pulping Technologies Ab | Straining device |
US5658428A (en) * | 1995-10-19 | 1997-08-19 | Kvaerner Pulping Technologies Ab | Method for impregnation in a single-vessel hydraulic digester |
US5885414A (en) * | 1997-08-18 | 1999-03-23 | Kvaerner Pulping Ab | Method of producing pulp with high alkali cooking in the last cooking stage |
WO2005116327A1 (en) | 2004-05-28 | 2005-12-08 | Metso Paper, Inc. | Central screen |
EP1764441A1 (en) * | 2005-09-15 | 2007-03-21 | Kvaerner Pulping AB | Continuous digester with fluid circulation |
CN101018906B (en) * | 2004-06-29 | 2010-06-16 | 美特索造纸公司 | Screen assembly for a pulp digester |
WO2015155642A1 (en) * | 2014-04-07 | 2015-10-15 | Stora Enso Oyj | A method of digesting cellulose fibrous material in a continuous digester |
Families Citing this family (26)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0613359A1 (en) * | 1991-11-19 | 1994-09-07 | The Procter & Gamble Company | Absorbent article having a nonwoven and apertured film coversheet |
US5766413A (en) * | 1993-04-23 | 1998-06-16 | Kvaerner Pulping Ab | Process for isothermal cooking pulp in a continuous digester |
SE502486C2 (en) * | 1994-02-18 | 1995-10-30 | Kvaerner Pulping Tech | Procedure and arrangement of valve for extraction and reverse flushing of ex. boiling liquid in cellulose boilers and their use in boiling sieves |
AU6405696A (en) * | 1995-06-29 | 1997-01-30 | Reijo K. Salminen | Continuous digester |
US5985096A (en) * | 1997-09-23 | 1999-11-16 | Ahlstrom Machinery Inc. | Vertical pulping digester having substantially constant diameter |
US6123808A (en) * | 1997-12-09 | 2000-09-26 | Ahlstrom Machinery Inc. | Distribution of dilution liquor to the discharge of a cellulose pulp digester |
US20010032711A1 (en) * | 1998-10-26 | 2001-10-25 | C. Bertil Stromberg | Pulp cooking with particular alkali profiles |
US20020069986A1 (en) * | 2000-06-16 | 2002-06-13 | Marcoccia Bruno S. | System and method for improved filtrate addition in a continuous digester |
SE515970C2 (en) * | 2000-11-03 | 2001-11-05 | Kvaerner Pulping Tech | Continuous boiling of pulp less used cooking liquor partly from the digester and partly from a subsequent pressure diffuser |
SE515971C2 (en) * | 2000-11-03 | 2001-11-05 | Kvaerner Pulping Tech | Continuous boiling of pulp with net mid-stream flow in the bottom portion of the boiler |
CN1308545C (en) * | 2003-08-26 | 2007-04-04 | 山东泉林纸业有限责任公司 | Vertical boiling pot for paper pulp |
FI117477B (en) * | 2004-05-28 | 2006-10-31 | Metso Paper Inc | strainer body |
US7799173B2 (en) * | 2007-01-18 | 2010-09-21 | Andritz Inc. | Screen plates having diagonal slots with curved inlets for a digester |
SE530744C2 (en) * | 2007-02-23 | 2008-09-02 | Metso Fiber Karlstad Ab | Steam phase boilers and a procedure for continuous boiling |
SE531717C2 (en) * | 2007-11-30 | 2009-07-21 | Metso Fiber Karlstad Ab | Kokarsil for a continuous cellulose pulp cooker |
SE532930C2 (en) * | 2008-03-20 | 2010-05-11 | Metso Fiber Karlstad Ab | Supply system including parallel pumps for a continuous boiler |
US7867363B2 (en) * | 2008-08-27 | 2011-01-11 | Metso Fiber Karlstad Ab | Continuous digester system |
SE533670C2 (en) * | 2009-04-01 | 2010-11-30 | Metso Fiber Karlstad Ab | System and method for controlling a continuous steam phase boiler |
US8951388B2 (en) * | 2011-04-08 | 2015-02-10 | Pec-Tech Engineering And Construction Pte Ltd | Method and system for efficient production of dissolving pulp in a kraft mill producing paper grade pulp with a continuous type digester |
WO2013105888A1 (en) | 2012-01-12 | 2013-07-18 | Metso Paper Sweden Ab | Profile bar screen for digester vessels |
CN102619122A (en) * | 2012-04-25 | 2012-08-01 | 湖南骏泰浆纸有限责任公司 | Upper circulation device of vertical continuous digester |
AU2013280241B2 (en) * | 2012-06-28 | 2016-02-11 | Shell Internationale Research Maatschappij B.V. | Digestion units configured for high yield biomass processing |
US9115214B2 (en) | 2012-09-24 | 2015-08-25 | Abengoa Bioenergy New Technologies, Llc | Methods for controlling pretreatment of biomass |
CN102978987A (en) * | 2012-12-24 | 2013-03-20 | 江苏华机环保设备有限责任公司 | Vertical cooker |
SE538326C2 (en) * | 2014-09-01 | 2016-05-17 | Valmet Oy | Profile bar screen for digester vessels |
RU208723U1 (en) * | 2021-09-14 | 2022-01-11 | Федеральное государственное бюджетное образовательное учреждение высшего образования "Санкт-Петербургский государственный университет промышленных технологий и дизайна" | VERTICAL BOILER |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
SE211196C1 (en) * | ||||
EP0476230A2 (en) * | 1990-09-17 | 1992-03-25 | Kamyr, Inc. | Extended kraft cooking with white liquor added to wash circulation |
Family Cites Families (13)
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US2414062A (en) * | 1944-05-02 | 1947-01-07 | Kamyr Ab | Apparatus for heating and controlling the temperature in a continuously operating digester |
US2852369A (en) * | 1954-09-17 | 1958-09-16 | Electric Steel Foundry | Digester strainer |
US2998064A (en) * | 1957-12-11 | 1961-08-29 | Improved Machinery Inc | Strainer construction |
SE325770B (en) * | 1969-10-13 | 1970-07-06 | Kamyr Ab | |
SE343344B (en) * | 1970-06-29 | 1972-03-06 | Kamyr Ab | |
US3755072A (en) † | 1970-10-23 | 1973-08-28 | Kamyr Ab | Strainer device for cellulose digester |
US3700548A (en) * | 1971-04-28 | 1972-10-24 | Improved Machinery Inc | Apparatus and methods of continuous digesting |
US3836463A (en) * | 1972-07-28 | 1974-09-17 | Gen Signal Corp | System and apparatus for cleaning bar grid |
US4193839A (en) * | 1976-05-11 | 1980-03-18 | Kamyr, Inc. | Flow control method and apparatus for continuous wood chip digester screenless liquor extractor |
US4436586A (en) * | 1982-01-22 | 1984-03-13 | Kamyr, Inc. | Method of producing kraft pulp using an acid prehydrolysis and pre-extraction |
JPS609287A (en) * | 1983-06-29 | 1985-01-18 | Fuji Photo Film Co Ltd | Cassette control device of video recording device |
US5328564A (en) * | 1990-09-17 | 1994-07-12 | Kamyr, Inc. | Modified digestion of paper pulp followed by ozone bleaching |
US5236554A (en) * | 1991-08-16 | 1993-08-17 | Kamyr, Inc. | Digester having plural screens with means for controlling liquid injection and withdrawal |
-
1992
- 1992-11-18 SE SE9203462A patent/SE500455C2/en not_active IP Right Cessation
-
1993
- 1993-03-16 NZ NZ252758A patent/NZ252758A/en unknown
- 1993-03-16 EP EP93912023A patent/EP0669998B2/en not_active Expired - Lifetime
- 1993-03-16 DE DE69312955T patent/DE69312955T3/en not_active Expired - Fee Related
- 1993-03-16 RU RU95112496A patent/RU2121537C1/en active
- 1993-03-16 AT AT93912023T patent/ATE156538T1/en not_active IP Right Cessation
- 1993-03-16 CA CA002149535A patent/CA2149535C/en not_active Expired - Fee Related
- 1993-03-16 AU AU63965/94A patent/AU684759B2/en not_active Ceased
- 1993-03-16 WO PCT/SE1993/000223 patent/WO1994011564A1/en active IP Right Grant
- 1993-03-16 ES ES93912023T patent/ES2105269T5/en not_active Expired - Lifetime
- 1993-03-16 BR BR9307478A patent/BR9307478A/en not_active IP Right Cessation
- 1993-03-16 JP JP51196994A patent/JP3287848B2/en not_active Expired - Fee Related
- 1993-04-08 RU RU95112494A patent/RU2113574C1/en active
- 1993-04-08 NZ NZ252340A patent/NZ252340A/en not_active IP Right Cessation
- 1993-04-08 CA CA002149434A patent/CA2149434C/en not_active Expired - Fee Related
- 1993-04-08 AT AT93910495T patent/ATE153398T1/en not_active IP Right Cessation
- 1993-04-08 ES ES93910495T patent/ES2103082T3/en not_active Expired - Lifetime
- 1993-04-08 AU AU40966/93A patent/AU680194B2/en not_active Ceased
- 1993-04-08 BR BR9307479A patent/BR9307479A/en not_active IP Right Cessation
- 1993-04-08 JP JP51197094A patent/JP3287849B2/en not_active Expired - Fee Related
- 1993-04-08 DE DE69310929T patent/DE69310929T2/en not_active Expired - Fee Related
- 1993-04-08 WO PCT/SE1993/000311 patent/WO1994011565A1/en active IP Right Grant
- 1993-04-08 EP EP93910495A patent/EP0673452B1/en not_active Expired - Lifetime
- 1993-07-16 US US08/092,420 patent/US5470437A/en not_active Expired - Lifetime
- 1993-10-08 BR BR9307480A patent/BR9307480A/en not_active IP Right Cessation
- 1993-10-08 WO PCT/SE1993/000816 patent/WO1994011566A1/en active IP Right Grant
- 1993-10-08 JP JP51197194A patent/JP3223285B2/en not_active Expired - Lifetime
- 1993-10-08 NZ NZ257659A patent/NZ257659A/en not_active IP Right Cessation
- 1993-10-08 EP EP93924847A patent/EP0673453B1/en not_active Expired - Lifetime
- 1993-10-08 AU AU54355/94A patent/AU673392B2/en not_active Ceased
- 1993-10-08 CA CA002149423A patent/CA2149423C/en not_active Expired - Lifetime
- 1993-10-08 ES ES93924847T patent/ES2077548T3/en not_active Expired - Lifetime
- 1993-10-08 DE DE0673453T patent/DE673453T1/en active Pending
- 1993-10-08 AT AT93924847T patent/ATE164400T1/en not_active IP Right Cessation
- 1993-10-08 DE DE69317670T patent/DE69317670T2/en not_active Expired - Fee Related
- 1993-10-08 RU RU95112468A patent/RU2126470C1/en active
- 1993-10-26 ZA ZA937958A patent/ZA937958B/en unknown
- 1993-10-26 ZA ZA937959A patent/ZA937959B/en unknown
- 1993-11-10 ZA ZA938390A patent/ZA938390B/en unknown
- 1993-11-17 MA MA23340A patent/MA23034A1/en unknown
- 1993-11-17 CN CN93121428A patent/CN1036728C/en not_active Expired - Fee Related
-
1994
- 1994-07-08 SE SE9402412A patent/SE9402412L/en not_active Application Discontinuation
- 1994-07-08 SE SE9402411A patent/SE513746C2/en not_active IP Right Cessation
-
1995
- 1995-03-22 US US08/408,706 patent/US5591303A/en not_active Expired - Lifetime
- 1995-03-31 US US08/415,203 patent/US5567280A/en not_active Expired - Lifetime
- 1995-05-17 FI FI952387A patent/FI113186B/en active
- 1995-05-17 FI FI952388A patent/FI115142B/en active IP Right Grant
- 1995-05-17 FI FI952389A patent/FI114718B/en not_active IP Right Cessation
- 1995-05-18 NO NO951973A patent/NO306478B1/en not_active IP Right Cessation
- 1995-05-18 NO NO951972A patent/NO306477B1/en not_active IP Right Cessation
- 1995-05-18 NO NO951974A patent/NO306479B1/en not_active IP Right Cessation
-
1997
- 1997-01-16 US US08/784,808 patent/US5827401A/en not_active Expired - Fee Related
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
SE211196C1 (en) * | ||||
EP0476230A2 (en) * | 1990-09-17 | 1992-03-25 | Kamyr, Inc. | Extended kraft cooking with white liquor added to wash circulation |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AU669274B2 (en) * | 1993-02-16 | 1996-05-30 | Kvaerner Pulping Technologies Ab | Straining device |
US5658428A (en) * | 1995-10-19 | 1997-08-19 | Kvaerner Pulping Technologies Ab | Method for impregnation in a single-vessel hydraulic digester |
US5885414A (en) * | 1997-08-18 | 1999-03-23 | Kvaerner Pulping Ab | Method of producing pulp with high alkali cooking in the last cooking stage |
WO2005116327A1 (en) | 2004-05-28 | 2005-12-08 | Metso Paper, Inc. | Central screen |
EP1778912A1 (en) * | 2004-05-28 | 2007-05-02 | Metso Paper, Inc. | Central screen |
EP1778912A4 (en) * | 2004-05-28 | 2010-06-16 | Metso Paper Inc | Central screen |
CN101018906B (en) * | 2004-06-29 | 2010-06-16 | 美特索造纸公司 | Screen assembly for a pulp digester |
EP1764441A1 (en) * | 2005-09-15 | 2007-03-21 | Kvaerner Pulping AB | Continuous digester with fluid circulation |
WO2015155642A1 (en) * | 2014-04-07 | 2015-10-15 | Stora Enso Oyj | A method of digesting cellulose fibrous material in a continuous digester |
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