Oxygen, Ozone Or Air Patents (Class 162/65)
  • Patent number: 7282115
    Abstract: Separation of dissolved and colloidal high molecular weight organic by-products from liquors or filtrates in a cellulosic pulping process to improve the overall efficiency of the process.
    Type: Grant
    Filed: November 20, 2003
    Date of Patent: October 16, 2007
    Inventor: Craig A. Bianchini
  • Patent number: 7267744
    Abstract: This invention provides a process for treating chemical woodpulp, or chemical cellulose including cotton linter, including the step of applying an electron processing technology (EPT) step to chemical woodpulp, or chemical cellulose, as the case may be, on an in-line basis to provide control of pulp viscosity or degree of polymerization (DP). The invention also provides a method of process control in treating the aforementioned woodpulp or cellulose, including the step of using radiation dose-viscosity relationship curve for applying an EPT step on an in-line basis. The in-line EPT step may, in one form of the invention, replace and hence eliminate a chemical DP reduction step.
    Type: Grant
    Filed: March 14, 2002
    Date of Patent: September 11, 2007
    Assignee: Sappi Limited
    Inventors: Ian Graveson, Heinzhorst Mobius, Derek Andrew Weightman
  • Patent number: 7214291
    Abstract: The invention relates to a method for the modification of cellulose fiber with the object of increasing the strength properties of the pulp. Cellulose derivative, preferably in the form of CMC, is added in association with alkali cooking and/or delignification of cellulose chips in a suspension with treatment fluid, in an amount exceeding 2 kg, preferably at least 5–7 kg, per ton of cellulose fibers. The addition of cellulose derivative to the suspension takes place when the suspension has a concentration of calcium released from the cellulose exceeding 20 mg/l. The conditions required for an efficient deposit of cellulose derivative onto the cellulose fibers can be established in this way, where the natural content of calcium in the wood raw material has been released and contributes to a high ionic strength, while an advantageous high temperature is established. No additional process stages are required and operating costs can be kept low.
    Type: Grant
    Filed: March 21, 2003
    Date of Patent: May 8, 2007
    Assignee: Kvaerner Pulping AB
    Inventors: Catrin Gustavsson, Vidar Snekkenes, Krister Olsson
  • Patent number: 7189306
    Abstract: This invention relates to a process of treating a lignocellulosic material to produce bio-ethanol. The process includes the steps of: (a) exposing the lignocellulosic material to conditions including a pH not less than about 8, and steam at a first pressure, to produce a step (a) product; (b) explosively discharging the step (a) product to a second pressure less than the first pressure to produce a step (b) product; and (c) further processing the step (b) product to produce bio-ethanol and other co-products. In another embodiment, the invention relates to a conical auger fractionation column. The fractionation column includes a column body having an input and an output. A conical filter is positioned inside the column body, the filter having a larger diameter end directed toward the input and a smaller diameter end directed toward the output.
    Type: Grant
    Filed: February 24, 2003
    Date of Patent: March 13, 2007
    Inventor: Gibson W. Gervais
  • Patent number: 7182835
    Abstract: Methods for bleaching chemical pulp are disclosed including dewatering the pulp to a concentration of from 25 to 40%, bleaching in a first chlorine dioxide stage, followed by a second alkaline bleaching stage, followed by a third chlorine dioxide bleaching stage, dewatering the bleached pulp to a concentration of from 10 to 40% and producing a filtrate, and recycling the filtrate to control the pulp concentration of the dewatered chemical pulp to from 8 to 15% in the first bleaching stage.
    Type: Grant
    Filed: August 14, 2001
    Date of Patent: February 27, 2007
    Assignee: Metso Paper, Inc.
    Inventors: Lars-Åke Lindström, Solveig Nordén, Gunnar Carré
  • Patent number: 7156952
    Abstract: The invention relates to a method and arrangement for alkaline oxygen delignification of cellulose pulp. By adding alkali in the final phase of the oxygen delignification one can ensure that an optimal predetermined end-pH is obtained. This provides advantages in the subsequent bleaching since the bleachability is substantially improved in the form of reduced need for bleaching chemicals.
    Type: Grant
    Filed: September 13, 2004
    Date of Patent: January 2, 2007
    Assignee: Kvaerner Pulping AB
    Inventor: Martin Ragnar
  • Patent number: 7097740
    Abstract: The invention relates to a method and a screen for screening two or more pulp mixtures with different roughness. The screen comprises a first screen cylinder and a second screen cylinder. A coarse first pulp mixture is fed into the inlet end of the first screen cylinder, and a second, less coarse pulp mixture is supplied to the second screen cylinder. The pulp mixtures are screened by means of a screen surface of the screen cylinders into accept that passes apertures provided in the screen surface and reject that does not pass the apertures. The accept from the second cylinder is conveyed by means of a guide tube provided between the cylinders towards the inlet end of the first cylinder and it is finally mixed with the first pulp mixture. The accept from the first and the second pulp mixture passes the screen surface of the first screen cylinder.
    Type: Grant
    Filed: April 10, 2003
    Date of Patent: August 29, 2006
    Assignee: Metso Paper Inc.
    Inventor: Timo Vuorinen
  • Patent number: 7090744
    Abstract: A process for making a composition for conversion to lyocell fiber where the process comprises pulping a raw material in a digester to provide an alkaline pulp, wherein the raw material comprises sawdust in an amount greater than 0 % up to 100 %; and contacting the alkaline pulp comprising cellulose and at least about 7 % hemicellulose under alkaline conditions with an amount of an oxidant sufficient to reduce the average degree of polymerization of the cellulose to within the range of from about 200 to about 1100, without substantially reducing the hemicellulose content of the pulp or substantially increasing the copper number.
    Type: Grant
    Filed: April 23, 2002
    Date of Patent: August 15, 2006
    Assignee: Weyerhaeuser Company
    Inventors: James E. Sealey, II, W. Harvey Persinger, Jr., Mengkui Luo, Brian Wester
  • Patent number: 7083704
    Abstract: The present invention provides compositions, useful for making lyocell fibers, having a high hemicellulose content, a low copper number and including cellulose that has a low average degree of polymerization (D.P.) and a narrow molecular weight distribution. Further, the present invention provides processes for making compositions, useful for making lyocell fibers, by contacting an alkaline pulp having a high hemicellulose content of at least about 7% with an oxidant sufficient to reduce the average degree of polymerization to about 200 to 1100 without substantially reducing the hemicellulose content or increasing the copper number of the pulp.
    Type: Grant
    Filed: October 10, 2001
    Date of Patent: August 1, 2006
    Assignee: Weyerhaeuser Company
    Inventors: James E. Sealey, II, W. Harvey Persinger, Jr., Mengkui Luo, Vincent A. Roscelli, Amar N. Neogi
  • Patent number: 7022837
    Abstract: The present inventors have discovered that the solution rheology of cellulose ethers prepared from cellulose pulp is altered by mercerizing and recovering cellulose pulp before preparing the cellulose ethers. For example, the solution viscosity of carboxymethyl cellulose (CMC) produced from mercerized and recovered cellulose pulp is significantly greater than that produced from non-mercerized cellulose pulp. The present invention provides a method of preparing cellulose ethers comprising the steps of (a) obtaining mercerized and recovered cellulose pulp, and (b) converting the mercerized and recovered cellulose pulp into the cellulose ethers. According to one embodiment, the cellulose pulp is southern softwood kraft and the mercerized cellulose pulp has a TAPPI 230 om-89 viscosity of at most 12 cP. This method, however, may be applied to all cellulose pulps, regardless of their viscosities, including those which, when mercerized, have a viscosity greater than 12 cP.
    Type: Grant
    Filed: October 31, 2001
    Date of Patent: April 4, 2006
    Assignee: BKI Holding Corporation
    Inventors: Roger Bruce Harding, Susan L. H. Crenshaw, Paul Eugene Gregory, Denise Hartnett Broughton
  • Patent number: 7014684
    Abstract: A process and a device for cleaning waste gas from pulp production, especially for cleaning waste gases from a bleaching reactor. Aerosols contained in the waste gas are removed and the gaseous impurities are scrubbed out of the waste gas by a scrubbing liquid.
    Type: Grant
    Filed: November 30, 2001
    Date of Patent: March 21, 2006
    Assignee: Linde Aktiengesellschaft
    Inventors: Wolfgang Dietrich, Hans Hiller
  • Patent number: 6946057
    Abstract: The present invention relates to a new and environmentally sound process for the manufacturing of a chemical pulp from lignocellulosic material with an integrated recovery system for recovery of pulping chemicals. The process is carried out in several stages involving a pre-treatment stage followed by one or more delignification stages using an alkaline buffer solution comprising alkali metaborate and sodium carbonate as major components. The alkaline components of the pulping liquor are recovered from a chemicals recovery furnace and at least a portion of the alkali is recycled and used for delignification without any prior reactions with lime or calcium compounds for generation of alkali hydroxide. A quinone based delignification catalyst may be added to be present during delignification.
    Type: Grant
    Filed: September 12, 2003
    Date of Patent: September 20, 2005
    Assignee: Kiram AB
    Inventor: Lars Stigsson
  • Patent number: 6942754
    Abstract: Xylooligosaccharide is produced from a lignocellulose pulp by enzyme-treating a lignocellulose pulp with hemicellulase, filtering the resultant reaction mixture to separate a liquid fraction from the enzyme-treated pulp, subjecting the separated liquid fraction to a permeation treatment through a separation membrane to separate a non-permeated fraction containing xylooligosaccharide-lignin complex with an increased concentration from a permeated fraction, collecting the non-permeated fraction, and separating and recovering xylooligosaccharide from the collected non-permeated fraction.
    Type: Grant
    Filed: April 22, 2002
    Date of Patent: September 13, 2005
    Assignee: Oji Paper Co., Ltd.
    Inventors: Yoshiya Izumi, Jun Sugiura, Hitoshi Kagawa, Naoya Azumi
  • Patent number: 6861023
    Abstract: A process for making lyocell fibers including the steps of pulping raw material in a digester to provide an alkaline pulp, wherein the raw material includes sawdust in an amount greater than 0% up to 100%; contacting the alkaline pulp including cellulose and at least about 7% hemicellulose under alkaline conditions with an amount of an oxidant sufficient to reduce the average degree of polymerization of the cellulose to the range of from about 200 to about 1100 without substantially reducing the hemicellulose content or substantially increasing the copper number of the pulp; and forming fibers from the pulp.
    Type: Grant
    Filed: April 23, 2002
    Date of Patent: March 1, 2005
    Assignee: Weyerhaeuser Company
    Inventors: James E. Sealey, II, W. Harvey Persinger, Jr., Mengkui Luo, Brian Wester
  • Patent number: 6841036
    Abstract: A system and process for the oxygen delignification of pulp consisting of a lignocellulose-containing material that has a mean concentration of 8-18% pulp consistency. The oxygen delignification takes place in a first stage with a short dwell time of about 3-6 minutes, at a low temperature of about 85° C. and under a low pressure of approximately 0-4 bar. A concluding stage has a longer dwell time of about 50-90 minutes, at a higher temperature of approximately 100° C. and under a higher pressure of about 8-10 bar.
    Type: Grant
    Filed: April 11, 2002
    Date of Patent: January 11, 2005
    Assignee: Kvaerner Pulping AB
    Inventors: Hakan Dahllof, Martin Ragnar
  • Patent number: 6824646
    Abstract: Lignocellulose pulp is bleached by bleaching a pulp in aqueous alkali solution with oxygen and treating the pulp with a hemicellulase, while a liquid fraction delivered from the enzyme treatment step is separated from the hemicellulase treated reaction mixture, and subjected to a penetration treatment through a separation membrane, for example, reverse osmosis membrane, to separate a permeated fraction from a non-permeated fraction; the permeated fraction is fed to the alkali-oxygen bleaching (oxygen delignification) step and is used as a liquid medium of the bleaching system.
    Type: Grant
    Filed: April 22, 2002
    Date of Patent: November 30, 2004
    Assignee: OJI Paper Co., Ltd.
    Inventors: Yoshiya Izumi, Jun Sugiura, Hitoshi Kagawa, Naoya Azumi
  • Patent number: 6808596
    Abstract: The system is for the oxygen delignification, in at least two reaction stages, of pulp that consists of lignocellulose-containing material having a mean concentration of 8%-18% pulp consistency. The oxygen delignification takes place in a first reaction stage that has a substantially constant low pressure during the whole delignification process. The second delignification stage has a substantially higher pressure and temperature and a longer dwell time. Readily delignifiable constituents in the pulp may react without the pulp being negatively affected so that the delignification process provides a very high degree of selectivity and an improved yield.
    Type: Grant
    Filed: May 19, 2003
    Date of Patent: October 26, 2004
    Assignee: Kvaerner Pulping AB
    Inventors: Hakan Dahllof, Martin Ragnar
  • Publication number: 20040200587
    Abstract: Bleached, Kraft chemical pulp having increased hemicellulose content compared to conventional Kraft chemical pulps. In one embodiment, the pulp has a hemicellulose content greater than about 17 weight percent as measured by the 18% caustic solubility test. In another aspect, a method for making wood cellulose pulp having increased hemicellulose content compared to conventional Kraft chemical pulps. In the method, a lignocellulosic material is pulped in caustic sulfide to provide a first brownstock, which is treated with oxygen to provide a second brownstock, which is then bleached to provide the pulp product.
    Type: Application
    Filed: April 8, 2003
    Publication date: October 14, 2004
    Inventors: William J. Herring, David B. Jack, Grant R. Bourree
  • Publication number: 20040200589
    Abstract: Bleached, Kraft chemical pulp having increased hemicellulose content compared to conventional Kraft chemical pulps. In one embodiment, the pulp has a hemicellulose content greater than about 17 weight percent as measured by the 18% caustic solubility test. In another aspect, a method for making wood cellulose pulp having increased hemicellulose content compared to conventional Kraft chemical pulps. In the method, a lignocellulosic material is pulped in caustic sulfide to provide a first brownstock, which is treated with oxygen to provide a second brownstock, which is then bleached to provide the pulp product.
    Type: Application
    Filed: April 8, 2003
    Publication date: October 14, 2004
    Inventors: William J. Herring, David B. Jack, Grant R. Bourree
  • Publication number: 20040188044
    Abstract: The invention relates to a process for the preparation of lignocellulosic substrates having a high digestibility. This process consists in bringing said lignocellulosic substrates, which have been ground beforehand and optionally moistened in the case of dry substrates, in a stirred reactor, into contact with ozone produced from a carrier gas, the ozone being present in the carrier gas in a concentration of between 80 and 200 g/m3 NTP, with a residence time of between 8 and 40 min in said reactor.
    Type: Application
    Filed: December 19, 2003
    Publication date: September 30, 2004
    Inventors: Alain Bailli, Christian Coste, Michel Dubois
  • Patent number: 6776876
    Abstract: Chemical cellulose pulp produced by alkaline delignification and having a kappa number of under 24 (e.g. 14 or below) having hexenuronic acid is treated to remove at least 50% of the hexenuronic acid (e.g. 90-97%) such as by treating the pulp at a temperature over 85° C. (e.g. about 90-180° C., preferably about 90-110° C.) at a pH between about 2-5 (e.g. about 2.5-4), which also results in a reduction of kappa number by at least two units (e.g. about 2-9 units, preferably about 3-6 units). The treatment time t, in minutes, is at least 0.5 exp(10517/(T+273)−24), where T is the treatment temperature in degrees C. The chemical cellulose pulp is bleached in at least one bleaching stage; where the bleaching stage is a chlorine dioxide, ozone, or peracid, treatment takes place before bleaching. Under some other circumstances treatment can take place simultaneous with bleaching or after bleaching.
    Type: Grant
    Filed: September 8, 1997
    Date of Patent: August 17, 2004
    Assignee: Andritz Oy
    Inventors: Tapani J. Vuorinen, U. Johanna Buchert, Anita B.-L. Teleman, T. Maija Tenkanen
  • Publication number: 20040154761
    Abstract: A method to enhance brightness in Chemical and Mechanical pulps comprising adding an organic sulfide chelant is described and claimed.
    Type: Application
    Filed: February 6, 2004
    Publication date: August 12, 2004
    Inventors: Prasad Y. Duggirala, Sergey M. Shevchenko, Kristine S. Salmen
  • Patent number: 6773547
    Abstract: Provided is a process for bleaching pulp with ozone. The process involves preparing a slurry of cellulosic pulp having a consistency in fibers of from 1 up to 5 weight %. Such a low consistency slurry is then mixed with high partial pressure ozone under high shear conditions. The ozone is then maintained in contact with the cellulosic fibers to effect bleaching of the fibers. The present process offers the advantages of bleaching using a low consistency slurry, with the added advantages of employing ozone.
    Type: Grant
    Filed: May 11, 2001
    Date of Patent: August 10, 2004
    Assignees: American Air Liquide, Inc., Air Liquide Canada
    Inventors: V. S. Meenakshi Sundaram, Steven A. Fisher, Sebastien Corbiel, Derek Hornsey
  • Publication number: 20040149404
    Abstract: The invention relates to a method of bleaching cellulose pulp in a bleach line having at least two bleaching steps D1, D2 of alkaline or acidic type, and a bleaching line for the method, in which the filtrate distribution is led up through the bleaching line in counter-current to the flow of cellulose pulp established in the bleaching line. Instead of a conventional filtrate distribution including filtrate tanks, a single joint main conduit 1 is used for the bleaching steps of the same type. Wash filtrate obtained from the wash steps of the same type used after or before the bleaching step, is led to a branch point A2, A4, A6 on the main conduit 1, that is positioned after the branch point for drawing off of wash and/or dilution liquor for the wash step in question A1, A3, A5, A7. All branch points in the joint main conduit are in open communication with each other in the main conduit, at least as seen in a direction from the last bleaching step.
    Type: Application
    Filed: January 13, 2004
    Publication date: August 5, 2004
    Inventors: Vidar Snekkenes, Lennart Gustavsson
  • Patent number: 6770168
    Abstract: A substantially sulfur free process for the manufacturing of a chemical pulp with an integrated recovery system for recovery of pulping chemicals is carried out on in several stages involving physical and chemical treatment of lignocellulosic material in order to increase accessibility of the lignocellulosic material to reactions with an oxygen-based delignification agent. Spent cellulose liquor comprising lignin components and spent chemical reagents is fully or partially oxidized in a gas generator wherein a stream of hot raw gas and a stream of alkaline chemicals and chemical reagents is formed for subsequent recycle and reuse in the pulp manufacturing process.
    Type: Grant
    Filed: August 14, 2001
    Date of Patent: August 3, 2004
    Assignee: Kiram AB
    Inventor: Lars Stigsson
  • Publication number: 20040112555
    Abstract: The present invention discloses methods of bleaching chemical pulp that combine xylanase enzymes with hydrogen peroxide, peracids, or a mixture. The method comprises the steps of carrying out a chemical pulping operation, optionally followed by delignifying the pulp with oxygen, then combining xylanase enzymes with hydrogen peroxide, peracids, or a mixture to bleach the pulp. The method allows the mill to use both xylanase and peracids in a single bleaching tower to decrease the usage of chlorine dioxide and other bleaching chemicals. The pulp bleaching method of the present invention may be performed in a pulp mill as part of a complex pulp bleaching process.
    Type: Application
    Filed: February 2, 2004
    Publication date: June 17, 2004
    Inventors: Jeffrey Tolan, Miro Suchy
  • Patent number: 6736934
    Abstract: The present invention relates to a method of pretreating, by acidification and chelation, of pulp to be bleached with peroxide. Especially, the invention relates to intensifying, and at the same time simplifying the pretreatment required by peroxide bleaching. It is characteristic of the invention to introduce pulp into an acid tower (14, 112) where the pressure is 0 to 20 bar, preferably 1 to 10 bar, and the temperature 75 to 130° C. preferably 80 to 110° C., to treat the pulp in acid tower (14, 112) at a pH of 2 to 6, preferably 3 to 4, for 20 to 240 minutes, for decreasing the kappa number by 1-9, preferably 2-6 kappa units, to transfer the pulp from acid tower (14, 112) to a tower (24) of a second treatment stage, to treat the pulp with either a complexing agent at a pH of 4 to 9, preferably 5 to 6, or with an oxidizing chemical such as chlorine dioxide, Caro's acid, peracids or equivalent, and to wash and/or press the pulp.
    Type: Grant
    Filed: July 28, 1997
    Date of Patent: May 18, 2004
    Assignee: Andritz Oy
    Inventors: Kaj Henricson, Olavi Pikka
  • Patent number: 6733625
    Abstract: The present invention relates to a method of treating chemical pulp in order to optimize the consumption of bleaching chemicals and to improve the quality of the pulp. Especially the invention relates to a method according to which filtrate obtained from a suitable stage of the washing of brown stock preferably cooked by an alkaline cooking method is treated with an oxidizing chemical prior to the oxygen stage following the brown stock washing.
    Type: Grant
    Filed: May 15, 2001
    Date of Patent: May 11, 2004
    Assignee: Andritz Oy
    Inventors: Kaj Henricson, Eero Kontturi, Olavi Pikka, Janne Vehmaa
  • Publication number: 20040084161
    Abstract: In a method for the production of fiber pulp for subsequent use in the production of a fiber web, especially a paper or cardboard web, the fiber pulp that was produced in a pulp production process is first loaded with an additive by way of a chemical precipitation reaction. The loaded pulp is then dried and available for subsequent utilization or formulated into a suitable form for shipment.
    Type: Application
    Filed: October 22, 2003
    Publication date: May 6, 2004
    Inventor: Helmut Heinzmann
  • Patent number: 6706143
    Abstract: The invention relates to methods for reducing the amount of halogenated organics produced during a halogen bleaching process for lignocellulosic pulp fibers. According to the disclosed invention, it has been discovered that the use of a chelating agent prior to a non-halogen containing bleaching stage of a pulp bleaching process is effective to increase the brightness of the resulting bleached pulp without the need to increase the amount of halogen compounds required to obtain the same pulp brightness and without adversely affecting the pulp viscosity and yield.
    Type: Grant
    Filed: July 3, 2000
    Date of Patent: March 16, 2004
    Assignee: International Paper Company
    Inventor: Ted Y. Tsai
  • Patent number: 6699358
    Abstract: A method for brightening chemical pulps with less than 18% lignin utilizing a magnesium compound in a sodium silicate solution to form a higher percentage of high molecular weight silicates. Such high molecular weight silicates preferentially adsorb transition metal impurities, which, if left in solution, would tend to decompose hydrogen peroxide and organic peroxides. Hydrogen peroxide is added to peroxide and peroxide/oxygen stages, while it is generated, along with organic peroxides during an oxygen stage.
    Type: Grant
    Filed: January 11, 2001
    Date of Patent: March 2, 2004
    Assignees: National Silicates Partnership, Research Foundation of State University of New York
    Inventors: Timothy D. Evans, Raymond C. Francis
  • Publication number: 20040026051
    Abstract: An environmentally friendly (ECF), yet commercially viable, process produces fully bleached (typically having a brightness of over 89 or 90% ISO) cellulose pulp using a (ZEND) treatment. Typically pulp is produced in an essentially sulphur-free pulping process (such as an soda/AQ process), and is then treated by a D-EO-, D-EP-, or D-EOP-sequence before the (ZEND) treatment. Optional oxygen delignification may also be used, and subsequent elemental-chlorine-free bleaching sequences may also be employed, although normally not necessary since the pulp after the (ZEND) treatment has high brightness and good viscosity (e.g. over 21 cP).
    Type: Application
    Filed: August 5, 2003
    Publication date: February 12, 2004
    Applicant: ANDRITZ INC.
    Inventor: C. Bertil Stromberg
  • Patent number: 6679972
    Abstract: A process for the bleaching of lignin present in pulp fibers in an aqueous environment such as a pulp suspension. The invention also relates to a process for producing paper or board from pulp containing bleached lignin. According to the invention carbon dioxide is used for the bleaching of lignin.
    Type: Grant
    Filed: February 15, 2002
    Date of Patent: January 20, 2004
    Assignee: AGA Aktiebolag
    Inventor: Anna Tigerström
  • Patent number: 6660128
    Abstract: A method for selectively delignifying lignocellulosic materials and bleaching of pulp and dyes using a combination of an oxidative enzyme and a metal complex. More specifically, the process involves the oxidation of a transition metal redox complex by a phenol oxidizing enzyme such as laccase or peroxidase to mediate the catalytic delignification of chemical pulp and bleaching of textile dye. This process is unique in that only a catalytic amount of metal complex mediator is required on softwood or hardwood kraft pulp, and that recycling or regeneration of the mediator for further pulp delignification is possible. The redox mediator is characterized in that it contains a transition metal ion coordinated with molecules or ions in such a way that the complexes have a formal redox potential between 0.5 and 1.2 volt measured against a normal hydrogen electrode.
    Type: Grant
    Filed: October 10, 2000
    Date of Patent: December 9, 2003
    Assignees: Pulp and Paper Research Institute of Canada, Universié de Montréal
    Inventors: Robert Bourbonnais, Dominic Rochefort, Michael G. Paice, Sylvie Renaud, Dónal Leech
  • Publication number: 20030213570
    Abstract: A pulp product that has a low COD is comprised of an unbleached pulp that is soaked and washed in alkaline water for a sufficient time so that the COD after soaking and washing is less than or equal to 3.0 kg/1000 kg of dry pulp. The pulp is produced by repetitively soaking and washing an unbleached pulp in alkaline water that is never allowed to drop below pH 7.0. The pulp is soaked and washed for a total of at least 400 minutes at an elevated temperature to produce the pulp product that has a low COD.
    Type: Application
    Filed: July 30, 2002
    Publication date: November 20, 2003
    Inventors: Michael D. Vrbanac, Brian Wester, Brian E. Dennis, Peter K. Lau, Julie A. Reimer, David W. Bickell
  • Publication number: 20030213571
    Abstract: Provided is a process for bleaching pulp with ozone. The process involves preparing a slurry of cellulosic pulp having a consistency in fibers of from 1-5 weight %. Such a low consistency slurry is then mixed with ozone under high shear conditions. The ozone is then maintained in contact with the cellulosic fibers to effect bleaching of the fibers. The present process offers the advantages of bleaching using a low consistency slurry, with the added advantages of employing ozone.
    Type: Application
    Filed: June 16, 2003
    Publication date: November 20, 2003
    Inventors: V.S. Meenakshi Sundaram, Derek Hornsey, Sebastien Corbeil, Steven A. Fisher
  • Publication number: 20030183351
    Abstract: The use of low specific gravity wood from thinning operations, for example, will produce a lower brownstock viscosity for a given kappa number target. A differential of 200-cP falling ball pulp viscosity has been detected from Kraft cooks of low and high specific gravity wood. Using low specific gravity wood can reduce the bleach stage temperature and the chemical dose needed in the bleach plant to produce lyocell pulp specifications. Low specific gravity wood also increases the ability to reduce pulp viscosity to very low levels without increasing the copper number of the pulp or the concentration of carbonyl in the pulp above acceptable levels.
    Type: Application
    Filed: January 2, 2003
    Publication date: October 2, 2003
    Inventors: James E. Sealey, W. Harvey Persinger, Kent Robarge, Mengkui Luo
  • Patent number: 6627041
    Abstract: A process for bleaching high bulk cellulosic fiber and producing a durable elevated curl index includes: (a) concurrently bleaching, heat treating and convolving cellulosic fiber pulp at elevated temperature and pressure at high consistency generally under conditions selected so as to preclude substantial fibrillation and attendant paper strength and fiber bonding development; and (b) recovering the pulp wherein the length weighted curl index of the treated fiber is at least about 20% higher than the length weighted curl index of the fiber prior to the heat treatment and convolving thereof. Preferably, the curl imparted to the fiber persists upon treatment for 30 minutes in a laboratory disintegrator at 3000 rpm at 1% consistency at a temperature of 125° F. Moreover, the curl may be imparted to the fiber in a disk refiner at very short residence times, on the order of several seconds or less.
    Type: Grant
    Filed: February 27, 2001
    Date of Patent: September 30, 2003
    Assignee: Georgia-Pacific Corporation
    Inventor: Jeffrey A. Lee
  • Publication number: 20030178163
    Abstract: A method of bleaching chemical pulp, comprising two bleaching stages (D0 and, respectively, D1) with chlorine dioxide as dominating bleaching chemical and at least one intermediate alkaline bleaching stage (E). The ingoing pulp is dewatered to a concentration of 25-40% before the first chlorine dioxide stage (D0) and to 10-40% after the second chlorine dioxide stage (D1). Filtrate from the dewatering after the second chlorine dioxide stage (D1) is re-cycled and utilized for controlling the pulp concentration to 8-15% of the dewatered pulp to the first chlorine dioxide stage (D0).
    Type: Application
    Filed: February 12, 2003
    Publication date: September 25, 2003
    Inventors: Lars-Ake Lindstrom, Solveig Norden, Gunnar Carre
  • Patent number: 6620292
    Abstract: A multi-function process is described for the separation of cellulose fibers from the other constituents of lignocellulosic biomass such as found in trees, grasses, agricultural waste, and waste paper with application in the preparation of feedstocks for use in the manufacture of paper, plastics, ethanol, and other chemicals. This process minimizes waste disposal problems since it uses only steam, water, and oxygen at elevated temperature in the range of 180° C. to 240° C. for 1 to 10 minutes plus a small amount of chemical reagents to maintain pH in the range 8 to 13. An energy recuperation function is important to the economic viability of the process.
    Type: Grant
    Filed: February 20, 2002
    Date of Patent: September 16, 2003
    Assignee: Purevision Technology, Inc.
    Inventor: Richard C. Wingerson
  • Publication number: 20030168190
    Abstract: The invention relates to a process for the bleaching of an aqueous lignocellulosic pulp under acidic conditions in the bleaching plant of a pulp mill. The bleached pulp is used for the production of paper or pulp. The selectivity of the bleaching agent towards primary reactions with lignin is enhanced by the use of a carbon dioxide providing medium in the pulp.
    Type: Application
    Filed: March 26, 2003
    Publication date: September 11, 2003
    Inventors: Petri Juhana Jokinen, Jarmo Tapio Kahala, Hannu Sakari Sonni
  • Publication number: 20030155086
    Abstract: The invention relates to improvements in the bleaching of a lignocellulosic pulp by adding carbon dioxide to provide a beneficial pH profile in the chlorine dioxide bleaching or delignification. The resulting bleached pulp is used in the production of paper or pulp. The invention also relates to the use of carbon dioxide for providing a desired pH profile in a chlorine dioxide bleaching stage.
    Type: Application
    Filed: March 3, 2003
    Publication date: August 21, 2003
    Inventors: Krister Sjoblom, Malena Rennel
  • Patent number: 6605181
    Abstract: A method and device for bleaching chemical paper pulp or dissolving wood pulp, which has been cooked and delignified without employing chlorine-containing chemicals, comprising a bleaching sequence which comprises optionally a first stage comprising a chelation treatment step; a second stage comprising a first peroxide treatment stage, wherein said first peroxide treatment stage is a delignifying peroxide treatment stage in which the amount of peroxide is less than 12 kilo/bone dry metric tons; a third stage comprising an acidic delignifying treatment stage, following said second stage and including a wash, and a fourth stage comprising a second peroxide treatment stage, following said third stage and including a wash, wherein said second peroxide treatment stage is a bleaching peroxide treatment, in which the amount of peroxide exceeds 3 kilo/bone dry metric tons and exceeds the amount of peroxide employed in said second step.
    Type: Grant
    Filed: March 28, 1994
    Date of Patent: August 12, 2003
    Assignee: Kvaerner Pulping Aktiebolag
    Inventors: Anders Bergqvist, Håkan Dahllöf, Marcelo Leite
  • Publication number: 20030131957
    Abstract: In one embodiment of the invention is disclosed a process for the production of microcrystalline cellulose comprising
    Type: Application
    Filed: November 20, 2002
    Publication date: July 17, 2003
    Inventors: David Schaible, Bob Sherwood
  • Publication number: 20030131958
    Abstract: A treatment sequence includes ozonation under acidic conditions followed by an acidic wash for enhancing the wet strength of a cellulosic fibrous material. Preferably the ozone treatment and the acidic wash are followed by a second ozonation step under acidic conditions. The fibrous cellulosic material obtained by this treatment sequence has a breaking length of at least 100 m. The wet strength of the cellulosic fibrous material is increased without the use of additives, such as wet strength agents. This use of ozone is very simple and efficient, and leads to highly pure products. The use of ozone as the only treatment chemical in particular avoids the introduction of so-called “non-process elements” (NPE) into the treatment system, for instance metal oxides such as MgO, which are frequently used in the oxidative treatment of pulps.
    Type: Application
    Filed: November 27, 2002
    Publication date: July 17, 2003
    Inventor: Thomas Jaschinski
  • Patent number: 6579411
    Abstract: A method of bleaching cellulose pulp with ozone includes pumping cellulose pulp in form of a fiber suspension having a consistency range of 5 to 25% with a high-consistency pump to a fluidizing Mixture in which oxygen and ozone containing gas is introduced and mixed into the pulp so as to generate a foam whereby the pulp fibers and the ozone used as the bleaching agent are brought to contact with each other, bleached, and the pulp is discharged from the mixer to a reaction vessel.
    Type: Grant
    Filed: June 5, 1995
    Date of Patent: June 17, 2003
    Assignee: Andritz Oy
    Inventors: Kaj Henricson, Torolf Laxen, Juhani Peltonen
  • Patent number: 6579412
    Abstract: Provided is a process for bleaching pulp with ozone. The process involves preparing a slurry of cellulosic pulp having a consistency in fibers of from 1-5 weight %. Such a low consistency slurry is then mixed with ozone under high shear conditions. The ozone is then maintained in contact with the cellulosic fibers to effect bleaching of the fibers. The present process offers the advantages of bleaching using a low consistency slurry, with the added advantages of employing ozone.
    Type: Grant
    Filed: July 24, 2002
    Date of Patent: June 17, 2003
    Assignees: L'Air Liquide - Societe' Anonyme a' Directoire et Conseil de Surveillance pour l'Etude et l'Exploitation des Procedes Georges Claude, American Air Liquide LP
    Inventors: V. S. Meenakshi Sundaram, Derek Hornsey, Sebastien Corbeil
  • Publication number: 20030102094
    Abstract: Bleaching device for pulp includes a container to which a supply of pulp and bleaching chemicals containing peroxide as well as discharge of bleached pulp are connected. The device comprises an oxygen measuring device a temperature measuring device and/or a carbon monoxide measuring device, which are arranged to measure oxygen concentration, temperature and/or carbon monoxide concentration, respectively, from the contents of the container such as from the gas volume of the same, or from a substance flow coming from the container, such as gas flow. The measuring device is connected to a data processing unit which is coupled to a controller for automatic control of the process. The process is especially a high consistency pulp bleaching of mechanical pulp, in which the consistency of pulp in the reaction area is at least 25%, advantageously at least 30%.
    Type: Application
    Filed: October 21, 2002
    Publication date: June 5, 2003
    Applicant: UPM-Kymmene Corporation
    Inventors: Tapio Tirri, Olli Dahl, Taisto Tienvieri, Jouko H. Lehto
  • Patent number: 6569284
    Abstract: The specification discloses an improved bleaching sequence which provides significant reduction in filtrate volumes and amounts of absorbable organic halide (AOX), color, and chemical oxygen demand (COD) in the effluent. These reductions are achieved without adversely affecting the brightness and viscosity properties of the bleached pulp and without a high capital cost and operating cost penalty or impact on existing mill processes. The bleaching sequence according to the invention for reducing filtrate volumes is an EOD1EOPD2 or EOPD1EOPD2 bleaching sequence wherein substantially all of the filtrates from the later bleaching stages are recycled to earlier bleaching stages and eventually treated in the initial EO or EOP stage prior to discharge from the plant.
    Type: Grant
    Filed: July 1, 1998
    Date of Patent: May 27, 2003
    Assignee: International Paper Company
    Inventors: Caifang Yin, Jasper H. Field
  • Publication number: 20030094251
    Abstract: A two-component mediator system is disclosed, wherein one component serves as a pro-oxidant and the other component serves as a pro-degradant and booster. When used in combination with a laccase, the two-component mediators enhance the bleaching of pulp. In addition, a composition comprising an oxidative enzyme, a pro-oxidant, and a pro-degradant, and a process for oxidizing a substrate that comprises treating the substrate with an oxidizing enzyme, a pro-oxidant, and a pro-degradant are disclosed. The pro-oxidant can be ascorbic acid, ascorbate, salicylic acid, salicylate, nicotinic acid, nicotinate, a hardwood black liquor, a softwood black liquor, ligno-organosolv, lignin sulfonate, or mixtures thereof. The pro-degradant can be urea, thiourea, sulfamic acid, sulfamide, guanidine, methylsulfonic acid, or mixtures thereof.
    Type: Application
    Filed: December 20, 2001
    Publication date: May 22, 2003
    Inventors: Huai N. Cheng, Simon Delagrave, Qu-Ming Gu, Dennis J. Murphy