Oxygen, Ozone Or Air Patents (Class 162/65)
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Patent number: 7282115Abstract: 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: GrantFiled: November 20, 2003Date of Patent: October 16, 2007Inventor: Craig A. Bianchini
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Patent number: 7267744Abstract: 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: GrantFiled: March 14, 2002Date of Patent: September 11, 2007Assignee: Sappi LimitedInventors: Ian Graveson, Heinzhorst Mobius, Derek Andrew Weightman
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Patent number: 7214291Abstract: 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: GrantFiled: March 21, 2003Date of Patent: May 8, 2007Assignee: Kvaerner Pulping ABInventors: Catrin Gustavsson, Vidar Snekkenes, Krister Olsson
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Patent number: 7189306Abstract: 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: GrantFiled: February 24, 2003Date of Patent: March 13, 2007Inventor: Gibson W. Gervais
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Patent number: 7182835Abstract: 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: GrantFiled: August 14, 2001Date of Patent: February 27, 2007Assignee: Metso Paper, Inc.Inventors: Lars-Åke Lindström, Solveig Nordén, Gunnar Carré
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Patent number: 7156952Abstract: 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: GrantFiled: September 13, 2004Date of Patent: January 2, 2007Assignee: Kvaerner Pulping ABInventor: Martin Ragnar
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Patent number: 7097740Abstract: 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: GrantFiled: April 10, 2003Date of Patent: August 29, 2006Assignee: Metso Paper Inc.Inventor: Timo Vuorinen
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Patent number: 7090744Abstract: 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: GrantFiled: April 23, 2002Date of Patent: August 15, 2006Assignee: Weyerhaeuser CompanyInventors: James E. Sealey, II, W. Harvey Persinger, Jr., Mengkui Luo, Brian Wester
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Patent number: 7083704Abstract: 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: GrantFiled: October 10, 2001Date of Patent: August 1, 2006Assignee: Weyerhaeuser CompanyInventors: James E. Sealey, II, W. Harvey Persinger, Jr., Mengkui Luo, Vincent A. Roscelli, Amar N. Neogi
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Patent number: 7022837Abstract: 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: GrantFiled: October 31, 2001Date of Patent: April 4, 2006Assignee: BKI Holding CorporationInventors: Roger Bruce Harding, Susan L. H. Crenshaw, Paul Eugene Gregory, Denise Hartnett Broughton
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Patent number: 7014684Abstract: 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: GrantFiled: November 30, 2001Date of Patent: March 21, 2006Assignee: Linde AktiengesellschaftInventors: Wolfgang Dietrich, Hans Hiller
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Patent number: 6946057Abstract: 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: GrantFiled: September 12, 2003Date of Patent: September 20, 2005Assignee: Kiram ABInventor: Lars Stigsson
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Patent number: 6942754Abstract: 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: GrantFiled: April 22, 2002Date of Patent: September 13, 2005Assignee: Oji Paper Co., Ltd.Inventors: Yoshiya Izumi, Jun Sugiura, Hitoshi Kagawa, Naoya Azumi
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Patent number: 6861023Abstract: 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: GrantFiled: April 23, 2002Date of Patent: March 1, 2005Assignee: Weyerhaeuser CompanyInventors: James E. Sealey, II, W. Harvey Persinger, Jr., Mengkui Luo, Brian Wester
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Patent number: 6841036Abstract: 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: GrantFiled: April 11, 2002Date of Patent: January 11, 2005Assignee: Kvaerner Pulping ABInventors: Hakan Dahllof, Martin Ragnar
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Patent number: 6824646Abstract: 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: GrantFiled: April 22, 2002Date of Patent: November 30, 2004Assignee: OJI Paper Co., Ltd.Inventors: Yoshiya Izumi, Jun Sugiura, Hitoshi Kagawa, Naoya Azumi
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Patent number: 6808596Abstract: 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: GrantFiled: May 19, 2003Date of Patent: October 26, 2004Assignee: Kvaerner Pulping ABInventors: Hakan Dahllof, Martin Ragnar
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Publication number: 20040200587Abstract: 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: ApplicationFiled: April 8, 2003Publication date: October 14, 2004Inventors: William J. Herring, David B. Jack, Grant R. Bourree
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Publication number: 20040200589Abstract: 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: ApplicationFiled: April 8, 2003Publication date: October 14, 2004Inventors: William J. Herring, David B. Jack, Grant R. Bourree
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Publication number: 20040188044Abstract: 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: ApplicationFiled: December 19, 2003Publication date: September 30, 2004Inventors: Alain Bailli, Christian Coste, Michel Dubois
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Patent number: 6776876Abstract: 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: GrantFiled: September 8, 1997Date of Patent: August 17, 2004Assignee: Andritz OyInventors: Tapani J. Vuorinen, U. Johanna Buchert, Anita B.-L. Teleman, T. Maija Tenkanen
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Publication number: 20040154761Abstract: A method to enhance brightness in Chemical and Mechanical pulps comprising adding an organic sulfide chelant is described and claimed.Type: ApplicationFiled: February 6, 2004Publication date: August 12, 2004Inventors: Prasad Y. Duggirala, Sergey M. Shevchenko, Kristine S. Salmen
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Patent number: 6773547Abstract: 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: GrantFiled: May 11, 2001Date of Patent: August 10, 2004Assignees: American Air Liquide, Inc., Air Liquide CanadaInventors: V. S. Meenakshi Sundaram, Steven A. Fisher, Sebastien Corbiel, Derek Hornsey
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Publication number: 20040149404Abstract: 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: ApplicationFiled: January 13, 2004Publication date: August 5, 2004Inventors: Vidar Snekkenes, Lennart Gustavsson
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Patent number: 6770168Abstract: 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: GrantFiled: August 14, 2001Date of Patent: August 3, 2004Assignee: Kiram ABInventor: Lars Stigsson
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Publication number: 20040112555Abstract: 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: ApplicationFiled: February 2, 2004Publication date: June 17, 2004Inventors: Jeffrey Tolan, Miro Suchy
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Patent number: 6736934Abstract: 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: GrantFiled: July 28, 1997Date of Patent: May 18, 2004Assignee: Andritz OyInventors: Kaj Henricson, Olavi Pikka
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Patent number: 6733625Abstract: 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: GrantFiled: May 15, 2001Date of Patent: May 11, 2004Assignee: Andritz OyInventors: Kaj Henricson, Eero Kontturi, Olavi Pikka, Janne Vehmaa
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Publication number: 20040084161Abstract: 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: ApplicationFiled: October 22, 2003Publication date: May 6, 2004Inventor: Helmut Heinzmann
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Patent number: 6706143Abstract: 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: GrantFiled: July 3, 2000Date of Patent: March 16, 2004Assignee: International Paper CompanyInventor: Ted Y. Tsai
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Patent number: 6699358Abstract: 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: GrantFiled: January 11, 2001Date of Patent: March 2, 2004Assignees: National Silicates Partnership, Research Foundation of State University of New YorkInventors: Timothy D. Evans, Raymond C. Francis
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Publication number: 20040026051Abstract: 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: ApplicationFiled: August 5, 2003Publication date: February 12, 2004Applicant: ANDRITZ INC.Inventor: C. Bertil Stromberg
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Patent number: 6679972Abstract: 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: GrantFiled: February 15, 2002Date of Patent: January 20, 2004Assignee: AGA AktiebolagInventor: Anna Tigerström
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Patent number: 6660128Abstract: 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: GrantFiled: October 10, 2000Date of Patent: December 9, 2003Assignees: Pulp and Paper Research Institute of Canada, Universié de MontréalInventors: Robert Bourbonnais, Dominic Rochefort, Michael G. Paice, Sylvie Renaud, Dónal Leech
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Publication number: 20030213570Abstract: 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: ApplicationFiled: July 30, 2002Publication date: November 20, 2003Inventors: Michael D. Vrbanac, Brian Wester, Brian E. Dennis, Peter K. Lau, Julie A. Reimer, David W. Bickell
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Publication number: 20030213571Abstract: 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: ApplicationFiled: June 16, 2003Publication date: November 20, 2003Inventors: V.S. Meenakshi Sundaram, Derek Hornsey, Sebastien Corbeil, Steven A. Fisher
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Publication number: 20030183351Abstract: 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: ApplicationFiled: January 2, 2003Publication date: October 2, 2003Inventors: James E. Sealey, W. Harvey Persinger, Kent Robarge, Mengkui Luo
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Patent number: 6627041Abstract: 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: GrantFiled: February 27, 2001Date of Patent: September 30, 2003Assignee: Georgia-Pacific CorporationInventor: Jeffrey A. Lee
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Publication number: 20030178163Abstract: 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: ApplicationFiled: February 12, 2003Publication date: September 25, 2003Inventors: Lars-Ake Lindstrom, Solveig Norden, Gunnar Carre
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Patent number: 6620292Abstract: 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: GrantFiled: February 20, 2002Date of Patent: September 16, 2003Assignee: Purevision Technology, Inc.Inventor: Richard C. Wingerson
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Publication number: 20030168190Abstract: 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: ApplicationFiled: March 26, 2003Publication date: September 11, 2003Inventors: Petri Juhana Jokinen, Jarmo Tapio Kahala, Hannu Sakari Sonni
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Publication number: 20030155086Abstract: 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: ApplicationFiled: March 3, 2003Publication date: August 21, 2003Inventors: Krister Sjoblom, Malena Rennel
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Patent number: 6605181Abstract: 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: GrantFiled: March 28, 1994Date of Patent: August 12, 2003Assignee: Kvaerner Pulping AktiebolagInventors: Anders Bergqvist, Håkan Dahllöf, Marcelo Leite
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Publication number: 20030131957Abstract: In one embodiment of the invention is disclosed a process for the production of microcrystalline cellulose comprisingType: ApplicationFiled: November 20, 2002Publication date: July 17, 2003Inventors: David Schaible, Bob Sherwood
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Publication number: 20030131958Abstract: 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: ApplicationFiled: November 27, 2002Publication date: July 17, 2003Inventor: Thomas Jaschinski
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Patent number: 6579411Abstract: 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: GrantFiled: June 5, 1995Date of Patent: June 17, 2003Assignee: Andritz OyInventors: Kaj Henricson, Torolf Laxen, Juhani Peltonen
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Patent number: 6579412Abstract: 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: GrantFiled: July 24, 2002Date of Patent: June 17, 2003Assignees: L'Air Liquide - Societe' Anonyme a' Directoire et Conseil de Surveillance pour l'Etude et l'Exploitation des Procedes Georges Claude, American Air Liquide LPInventors: V. S. Meenakshi Sundaram, Derek Hornsey, Sebastien Corbeil
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Publication number: 20030102094Abstract: 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: ApplicationFiled: October 21, 2002Publication date: June 5, 2003Applicant: UPM-Kymmene CorporationInventors: Tapio Tirri, Olli Dahl, Taisto Tienvieri, Jouko H. Lehto
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Patent number: 6569284Abstract: 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: GrantFiled: July 1, 1998Date of Patent: May 27, 2003Assignee: International Paper CompanyInventors: Caifang Yin, Jasper H. Field
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Publication number: 20030094251Abstract: 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: ApplicationFiled: December 20, 2001Publication date: May 22, 2003Inventors: Huai N. Cheng, Simon Delagrave, Qu-Ming Gu, Dennis J. Murphy