EP2625332A1 - Process for the drying of pulp and a suction roll used for the drying of pulp - Google Patents
Process for the drying of pulp and a suction roll used for the drying of pulpInfo
- Publication number
- EP2625332A1 EP2625332A1 EP11830274.4A EP11830274A EP2625332A1 EP 2625332 A1 EP2625332 A1 EP 2625332A1 EP 11830274 A EP11830274 A EP 11830274A EP 2625332 A1 EP2625332 A1 EP 2625332A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- pulp
- roll
- suction roll
- drying
- surface area
- 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
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- D21F3/00—Press section of machines for making continuous webs of paper
- D21F3/02—Wet presses
- D21F3/10—Suction rolls, e.g. couch rolls
-
- 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
- D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
- D21C9/18—De-watering; Elimination of cooking or pulp-treating liquors from the pulp
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21G—CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES
- D21G3/00—Doctors
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21G—CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES
- D21G3/00—Doctors
- D21G3/005—Doctor knifes
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B25/00—Details of general application not covered by group F26B21/00 or F26B23/00
- F26B25/20—Rollers
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B5/00—Drying solid materials or objects by processes not involving the application of heat
- F26B5/12—Drying solid materials or objects by processes not involving the application of heat by suction
Definitions
- the present invention relates to a process for the drying of pulp and a suction roll for the drying of pulp.
- Pulp comprising cellulosic fibers is used for the production of paper or paperboard.
- the pulp can be produced in many different ways and many different cellulosic fibers may be used.
- the produced pulp is conducted to a wire in order to form a fibrous web which eventually will form a paper or paperboard.
- a wire When the pulp and the paper or paperboard is manufactured at the same location it is easy to transport the pulp, in a wet state, to the paper or paperboard machine.
- the production of the pulp and the production of the paper or paperboard can also be done at different locations and it is then necessary to transport the pulp to the paper or paperboard manufacturing location. It is thus desirable to dry the pulp before transportation in order to avoid expensive transports due to unnecessary transport of water.
- the fourdrinier machine is most commonly used and the pulp is deposited from a headbox to a continuous wire. The water in the pulp drains through the wire forming a pulp mat. After the initial free drainage through the wire, the pulp mat is further dewatered, as it is carried on the wire, by the application of increased vacuum. The vacuum is applied to the underside of the pulp mat by vacuum boxes and/or a couch roll located prior to the removal of the mat from the wire. The pulp mat is then conducted to the press section and the drying section in which further water is removed.
- Dewatering can be maximized in many different ways. By optimizing the performance of the vacuum section, press section and dryer section of a pulp drying machine, it is possible to increase the dewatering in an as efficient way as possible. It is also advantageous to keep the pulp temperature as high as possible in order to improve water removal since the viscosity of the water is decreased at higher temperatures. Furthermore, it is preferred to keep the pH of the pulp low, preferably around 4-5, since the fibers are not as swollen at lower pH and thus facilitates drainage of the water. Another possibility is to add chemicals to the pulp which improves drainage. One example is described in WO0218704.
- the present invention relates a process for the drying of pulp which process comprises the steps of, providing a pulp comprising cellulosic fibers, conducting the pulp to a wire, dewatering the pulp by the aid of a suction roll wherein the suction roll has a open surface area of above 60%. By increasing the open surface area of the suction roll the dewatering of the pulp is increased.
- the suction roll has a shell thickness of above 50 mm. It is preferred to increase the shell thickness of the roll shell since the open surface area is increased. In this way the strength of the roll is still good and it is possible to still have high negative pressure (vacuum) or suction in the roll.
- the suction roll preferably comprises a doctor blade. It is preferred that the doctor blade is an air knife. The doctor blade is used in order to clean the open surface area of the suction roll.
- the dry content of the pulp is preferably between 15-30% by weight after passing the suction roll. It is thus possible to increase the dry content of the pulp by the use of the suction roll with increased open surface area.
- the present invention further relates to a suction roll for the drying of pulp wherein the suction roll has an open surface area of above 60%.
- the shell of the suction roll has a thickness of above 50 mm. Increased shell thickness will increase the strength of the roll and thus make it possible to further increase the open surface area of the roll and/or the negative pressure of the roll, i.e. increased suction.
- the suction roll preferably comprises a doctor blade. It is preferred that the doctor blade is an air knife. The doctor blade is used in order to clean and remove the water from the open surface areas of the roll.
- FIG. 1 shows a schematic figure of the suction roll
- Fig. 2 shows a schematic figure of the open area surfaces of the suction roll.
- the present invention relates to process for the drying of pulp and a suction roll used for the drying of pulp. It has been shown that by increasing the open surface area of the roll, i.e. increase the number and/or size of the holes of the shell of the roll, it is possible to improve the dewatering of the pulp in a very energy efficient way.
- the amount of water drained from the pulp can in this way be increased but without increasing the energy needed, i.e. by using the same negative pressure, i.e. suction, of the roll.
- the increased amount open surface area will allow higher negative pressure and it is thus possible to increase the negative pressure and increase the amount of water being dewatered from the pulp.
- the amount of open surface area of the suction roll shell is above 60% of the total area of the roll shell, preferably above 70%.
- the open surface area is preferably in the form of several holes being evenly distributed over the whole surface of the roll shell. It is possible that the open surface area is bigger in the outer part of the shell and smaller in the inner part of the shell, i.e. the holes forming the open surface area are in a tapered form.
- the amount open area surface of the suction roll according to the invention shall preferably constitute of more than 60% of the total area of the surface roll, seeing both to the inner side or the outer side of the roll. By increasing the size of the holes forming the open surface area of the roll shell, marking might occur on the pulp mat.
- suction roll vacuum markings may be beneficial in the subsequent drying steps of the pulp mat.
- the use of air drying is the most commonly used drying technique in pulp drying machines and it is then beneficial to have as large surface area as possible and the vacuum roll markings will increase the surface area of the pulp mat and thus improve the drying.
- the thickness of the roll shell is increased compared to drying rolls used in prior art. Due to the increased amount of open surface area of the roll it might be necessary or at least advantageous to increase the thickness of the roll shell in order to provide the roll with sufficient strength. It is also possible to increase the negative pressure of the suction roll since the thickness of the roll shell is increased.
- the thickness of the roll shell is preferably above 50 mm, even more preferred above 60 mm. There is an optimal ratio between the amount of open surface area and thickness of the shell. If the amount of open surface area is high, the thickness of the roll shell is increased in order to be able to run the suction roll in the best way, i.e. in the most efficient way.
- the negative pressure (vacuum) inside the roll is preferably between 1 0-1 00 kPa.
- the suction roll is preferably provided with at least one doctor blade.
- the main purpose of the doctor blade is to remove the water from the open surface area, i.e. from the holes. Since the centrifugal force of the roll is low, it is not possible for the drained water to be removed from the roll. The doctor blade will thus remove the water from the holes making sure that the efficiency of the suction roll is not decreased.
- the doctor blade may also remove impurities, such as deposits, from the suction roll.
- the doctor blade is preferably an air knife.
- the air knife comprises an air nozzle which directs pressurized air at the surface of the roll.
- the air knife may comprise more than one air nozzles. It is preferred that the width of the air knife covers the entire width of the shell surface.
- the width of the at least one nozzle is preferably wide enough to allow the formation of an air knife capable of removing water from the open surface areas of the roll, but narrow enough to minimize the amount of air required.
- the at least one air nozzle is preferably located far enough from the surface of the roll shell in order to avoid deposit of the removed water and/or deposits on the nozzle itself, but close enough to remove the water and/or deposits from the open surface area of the roll.
- the air of the air knife should preferably be pressured to the point where the air knife will be able to remove water and/or deposits.
- the process according to the invention it is possible to increase the dry content of the pulp already at the wet end of the pulp drying machine. It is preferred that the dry content of the pulp after passing the suction roll of the invention is preferably between 15-30 % by weight. By increasing the dry content of the pulp at an early stage in the pulp drying machine it is possible to use higher pressure in the subsequent press section.
- the suction roll according to the invention can be of any conventional type used for the drying of pulp and/or production of paper or paperboard, with the difference that the amount of open surface area is increased. Other components, such as type of shell, vacuum system or water removal system, etc can be of any conventional type.
- the suction roll according to the invention can be used in any conventional pulp drying machine or process. It is preferred to use it instead of a couch roll in a fourdrinier machine.
- the lumpbreaker roll preferably comprises a felt, i.e. a felted lumpbreaker roll.
- the lumpbreaker roll preferably forms a nip together with the suction roll.
- the nip pressure between the lumpbreaker roll and the suction roll is preferably between 25-40 kN/m. It is advantageous to use the lumpbreaker roll since it can increase the drying of the pulp since the drained water tends to go to the open surface area of the suction roll to a greater extent.
- FIG 1 and figure 2 shows a suction roll (1 ) according to the invention.
- a wire (2) is conducting a pulp mat or web.
- the wire (2) is partly wrapped round the suction roll (1 ).
- the suction roll (1 ) comprises a roll shell (3) which rotates around a non rotating central roll core.
- the roll shell (3) comprises a number of holes forming an open surface area.
- the open area surface (9) is in the form of holes that have been formed by drilling of the roll shell (3).
- the open surface area (9) constitutes at least 60% of the total surface of the roll shell (3).
- the holes makes sure that the pulp mat on the wire (2) will be exposed to the lower pressure (vacuum) inside the roll (1 ).
- the roll shell (3) is made of metal and the thickness of the roll shell (3) is above 50 mm.
- the roll (1 ) further comprises vacuum seals (4) which make sure that it is possible to create a negative pressure inside the roll.
- the roll (1 ) further comprises a non-rotating suction quadrant (5).
- the quadrant (5) creates the negative pressure or vacuum inside the roll.
- the water withdrawn from the pulp is removed by a white water removal system (6) which removes water from inside the roll (1 ).
- the withdrawn water is also removed by the aid of an air knife (7).
- the air knife (7) removes water from the open surface areas (9) of the roll shell (3).
- the roll (1 ) also comprises an end plate (8).
- the pulp may be of any conventional type. It can be mechanical, chemimechanical, chemithermomechnical and/or chemical pulp.
- the cellulosic fibers of the pulp may be of any conventional kind wood cellulose fibers, such as hardwood fibers, softwood fibers or agricultural raw materials or waste products.
Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE1051037A SE535820C2 (en) | 2010-10-05 | 2010-10-05 | Process for drying pulp using a perforated suction roll |
PCT/IB2011/054356 WO2012046184A1 (en) | 2010-10-05 | 2011-10-04 | Process for the drying of pulp and a suction roll used for the drying of pulp |
Publications (2)
Publication Number | Publication Date |
---|---|
EP2625332A1 true EP2625332A1 (en) | 2013-08-14 |
EP2625332A4 EP2625332A4 (en) | 2014-06-11 |
Family
ID=45927283
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP11830274.4A Pending EP2625332A4 (en) | 2010-10-05 | 2011-10-04 | Process for the drying of pulp and a suction roll used for the drying of pulp |
Country Status (7)
Country | Link |
---|---|
EP (1) | EP2625332A4 (en) |
CN (1) | CN103154360A (en) |
BR (1) | BR112013008132A2 (en) |
NZ (1) | NZ608170A (en) |
RU (1) | RU2582464C2 (en) |
SE (1) | SE535820C2 (en) |
WO (1) | WO2012046184A1 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20230294358A1 (en) * | 2020-02-12 | 2023-09-21 | Hewlett-Packard Development Company, L.P. | 3d printing with movable slurry dispenser |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB629633A (en) * | 1947-03-27 | 1949-09-23 | Millspaugh Ltd | Suction rolls for paper-making machines |
US3265559A (en) * | 1965-05-03 | 1966-08-09 | Time Inc | Paper press section |
US5140749A (en) * | 1989-01-09 | 1992-08-25 | Valmet Paper Machinery Inc. | Method for the manufacture of rolls or cylinders of a paper machine and articles produced thereby |
DE29822227U1 (en) * | 1997-12-15 | 1999-02-11 | Valmet Corp | Suction roll arrangement for the press of a pulp drying machine |
WO2002018704A1 (en) * | 2000-08-31 | 2002-03-07 | Ondeo Nalco Company | Enhanced vacuum dewatering of pulp |
US20030008757A1 (en) * | 1997-12-10 | 2003-01-09 | Metso Paper, Inc. | Roll for a paper or board machine |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CA924146A (en) * | 1970-08-20 | 1973-04-10 | Malashenko Alexander | Roll surface formulation |
DE2646116C3 (en) * | 1976-10-13 | 1979-10-18 | Hermann Finckh, Maschinenfabrik, 7417 Pfullingen | Suction roll for paper machines |
SU638658A1 (en) * | 1977-07-06 | 1978-12-25 | Центральный Научно-Исследовательский И Проектно-Конструкторский Институт По Проектированию Оборудования Для Целлюлозно-Бумажной Промышленности | Paper-making machine drying cylinder |
CN2052415U (en) * | 1988-07-18 | 1990-02-07 | 王锡元 | Cylinder machine paper-shaper with clip wire-cloth |
FI20010721A (en) * | 2001-04-06 | 2002-10-07 | Metso Paper Inc | Tape for a press roll and a press concept |
FI116076B (en) * | 2004-02-10 | 2005-09-15 | Metso Paper Inc | Grooved forming drum |
DE102004029289A1 (en) * | 2004-06-17 | 2005-12-29 | Voith Paper Patent Gmbh | Machine using double belt former to make fibrous papermaking web from suspension, includes screen belts wrapping suction rollers and suction boxes |
-
2010
- 2010-10-05 SE SE1051037A patent/SE535820C2/en unknown
-
2011
- 2011-10-04 NZ NZ60817011A patent/NZ608170A/en not_active IP Right Cessation
- 2011-10-04 BR BR112013008132A patent/BR112013008132A2/en not_active Application Discontinuation
- 2011-10-04 RU RU2013120321/12A patent/RU2582464C2/en active
- 2011-10-04 CN CN2011800481896A patent/CN103154360A/en active Pending
- 2011-10-04 EP EP11830274.4A patent/EP2625332A4/en active Pending
- 2011-10-04 WO PCT/IB2011/054356 patent/WO2012046184A1/en active Application Filing
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB629633A (en) * | 1947-03-27 | 1949-09-23 | Millspaugh Ltd | Suction rolls for paper-making machines |
US3265559A (en) * | 1965-05-03 | 1966-08-09 | Time Inc | Paper press section |
US5140749A (en) * | 1989-01-09 | 1992-08-25 | Valmet Paper Machinery Inc. | Method for the manufacture of rolls or cylinders of a paper machine and articles produced thereby |
US20030008757A1 (en) * | 1997-12-10 | 2003-01-09 | Metso Paper, Inc. | Roll for a paper or board machine |
DE29822227U1 (en) * | 1997-12-15 | 1999-02-11 | Valmet Corp | Suction roll arrangement for the press of a pulp drying machine |
WO2002018704A1 (en) * | 2000-08-31 | 2002-03-07 | Ondeo Nalco Company | Enhanced vacuum dewatering of pulp |
Non-Patent Citations (1)
Title |
---|
See also references of WO2012046184A1 * |
Also Published As
Publication number | Publication date |
---|---|
NZ608170A (en) | 2015-04-24 |
BR112013008132A2 (en) | 2016-08-09 |
CN103154360A (en) | 2013-06-12 |
EP2625332A4 (en) | 2014-06-11 |
WO2012046184A1 (en) | 2012-04-12 |
RU2013120321A (en) | 2014-11-20 |
SE1051037A1 (en) | 2012-04-06 |
RU2582464C2 (en) | 2016-04-27 |
SE535820C2 (en) | 2013-01-02 |
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Legal Events
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A4 | Supplementary search report drawn up and despatched |
Effective date: 20140512 |
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RIC1 | Information provided on ipc code assigned before grant |
Ipc: F26B 5/12 20060101ALI20140506BHEP Ipc: D21G 3/00 20060101ALI20140506BHEP Ipc: F26B 13/16 20060101ALI20140506BHEP Ipc: F26B 25/20 20060101ALI20140506BHEP Ipc: D21C 9/18 20060101AFI20140506BHEP Ipc: D21F 3/10 20060101ALI20140506BHEP |
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