With Addition Of Chemicals Prior To Reuse Patents (Class 162/38)
  • Patent number: 10328384
    Abstract: A hydrocyclone for separating a vapor from a carrier gas is disclosed. The hydrocyclone comprises one or more nozzles. A cryogenic liquid is injected to a tangential feed inlet at a velocity that induces a tangential flow and a cyclone vortex in the hydrocyclone. The carrier gas is injected into the cryogenic liquid, causing the vapor to dissolve, condense, desublimate, or a combination thereof, forming a vapor-depleted carrier gas and a vapor-enriched cryogenic liquid. The vapor-depleted carrier gas is drawn through a vortex finder and the vapor-enriched cryogenic liquid is drawn through an apex nozzle outlet. In this manner, the vapor is removed from the carrier gas.
    Type: Grant
    Filed: February 22, 2017
    Date of Patent: June 25, 2019
    Assignee: Sustainable Energy Solutions, LLC
    Inventors: Larry Baxter, Christopher Hoeger, Aaron Sayre, Skyler Chamberlain, Kyler Stitt, Eric Mansfield, Stephanie Burt, Andrew Baxter, Jacom Chamberlain, Nathan Davis
  • Patent number: 10316343
    Abstract: The present invention relates to compositions comprising: a polypeptide having cellulolytic enhancing activity and a liquor. The present invention also relates to methods of using the compositions.
    Type: Grant
    Filed: June 7, 2016
    Date of Patent: June 11, 2019
    Assignees: Novozymes, Inc., Novozymes North America, Inc.
    Inventors: Jason Quinlan, Feng Xu, Matt Sweeney, Don Higgins, Hui Xu
  • Patent number: 9011640
    Abstract: The invention relates to a method for obtaining cellulose by separating lignin from a biomass comprising lignocellulose in the form of plants or plant parts, wherein the biomass comprising lignocellulose is solubilized in a boiler in an alkaline medium comprising alkanol amine, and dissolved lignin is separated from the resulting raw cellulose. Said method is characterized in that the biomass comprising lignocellulose is not from a wood source, and is solubilized at a temperature of less than approximately 170° C. in a solubilizing agent based on alkanol amine and water, wherein the weight ratio of alkanol amine to water is set to 80:20 to 20:80, and raw cellulose thus produced is separated from the waste lye using a typical method. Said method is particularly advantageous for obtaining cellulose from annual plants, particularly wheat straw. The method is advantageously improved in that the solubilization takes place in the presence of a catalyst, particularly of anthrachinon.
    Type: Grant
    Filed: February 25, 2010
    Date of Patent: April 21, 2015
    Assignee: Zylum Beteiligungsgesellschaft mbH & Co Patente II KG
    Inventors: Rudolf Patt, Andreas Kreipl
  • Publication number: 20120132379
    Abstract: The invention relates to a method for obtaining cellulose by separating lignin from a biomass comprising lignocellulose in the form of plants or plant parts, wherein the biomass comprising lignocellulose is solubilized in a boiler in an alkaline medium comprising alkanol amine, and dissolved lignin is separated from the resulting raw cellulose. Said method is characterized in that the biomass comprising lignocellulose is not from a wood source, and is solubilized at a temperature of less than approximately 170° C. in a solubilizing agent based on alkanol amine and water, wherein the weight ratio of alkanol amine to water is set to 80:20 to 20:80, and raw cellulose thus produced is separated from the waste lye using a typical method. Said method is particularly advantageous for obtaining cellulose from annual plants, particularly wheat straw. The method is advantageously improved in that the solubilization takes place in the presence of a catalyst, particularly of anthrachinon.
    Type: Application
    Filed: February 25, 2010
    Publication date: May 31, 2012
    Applicant: Zylum Beteiligungsgesellschaft MBH & Co Patente II KG
    Inventors: Rudolf Patt, Andreas Kreipl
  • Publication number: 20110272108
    Abstract: The present invention relates to an integrated process for producing pulp and at least one organic liquid or liquefiable material of value, wherein a) a lignocellulose-comprising starting material is provided and subjected to digestion with an aqueous-alkaline treatment medium, b) a cellulose-enriched fraction and a cellulose-depleted black liquor are isolated from the digested material, c) the black liquor is subjected to a treatment to give at least one organic liquid or liquefiable material of value and at least one offgas stream, d) at least one of the offgas streams obtained in step c) is recycled to the process for producing pulp and utilized.
    Type: Application
    Filed: May 5, 2011
    Publication date: November 10, 2011
    Applicant: BASF SE
    Inventors: ROMAN PROCHAZKA, STEFAN BITTERLICH, STEPHAN DEUERLEIN, OTTO MACHHAMMER, DIRK KLINGLER, EMMANOUIL PANTOUFLAS
  • Publication number: 20090056889
    Abstract: The invention relates to a process of detoxifying pretreated lignocellulose-containing material comprising washing the pretreated lignocellulose-containing material in a washing solution and treating the used washing solution to remove an enzyme inhibitor and/or an inhibitor of a fermenting organism before recycling the used washing solution.
    Type: Application
    Filed: September 3, 2008
    Publication date: March 5, 2009
    Applicants: Novozymes A/S, Cofco LTD.
    Inventors: Haiyu Ren, Hong Zhi Huang, Jie Zheng
  • Patent number: 7445691
    Abstract: The method is for pre-treatment of chips that are fed to a sulphate cooking process. Through acidification of the chips in an acidic treatment fluid with a subsequent draining of free treatment fluid before subsequent steaming or wet-steaming, a high concentration of free hydrogen ions is established within the chip pieces. When the chips are subsequently formed into slurry with preferably a sulphide-rich alkali cooking fluid, H2S is formed locally in the chip pieces which gives a yield-increasing effect in the subsequent cooking step of 1-3%.
    Type: Grant
    Filed: March 25, 2004
    Date of Patent: November 4, 2008
    Assignee: Metso Fiber Karlstad AB
    Inventors: Vidar Snekkenes, Krister Olsson
  • Patent number: 7303649
    Abstract: In a process of treating wood chips for reduction of the concentration of undesirable inorganic elements prior to cooking in a production line for chemical pulp, the wood chips, having entrapped air, are treated with an aqueous leaching liquor at elevated temperature and pressure, followed by draining at atmospheric pressure or below atmospheric pressure, the pressures being controlled to yield a moisture content in the wood chips as low as possible for adequate leaching result and behavior of the chips in a subsequent digester. The aqueous leaching liquor is e.g. pulp mill process water with a low content of undesirable inorganic components, such as bleach plant spent liquor or condensate. The aqueous leaching liquor drained from the treated wood chips may be purified and recycled back to the process.
    Type: Grant
    Filed: November 22, 2002
    Date of Patent: December 4, 2007
    Assignee: STFI Skogsindustrins Tekniska Forskningsinstitut AB
    Inventors: Harald Brelid, Peter Axegard
  • Patent number: 6955743
    Abstract: The invention relates to a process for recovering and producing chemicals in a pulp production process where organic chemicals, such as formic acid and acetic acid, are used as cooking chemicals. The process of the invention is based on regeneration of cooking acids and formation of additional cooking acids and furfural by evaporating the cooking liquor and then separating acetic acid, formic acid, furfural and water. The separation is preferably carried out by distillation using the furfural formed in the process as a distilling aid in the distillation.
    Type: Grant
    Filed: December 28, 2001
    Date of Patent: October 18, 2005
    Assignee: Chempolis Oy
    Inventors: Esa Rousu, Pasi Rousu, Juha Anttila, Juha Tanskanen, Päivi Rousu
  • 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: 6746568
    Abstract: A method in bleaching of pulp is described, in which the pulp is subjected to a peroxide bleaching step, whereupon the pulp is washed and the washing liquid from the washing is separated from the pulp in the form of a filtrate. The method is characterised in that the filtrate is treated with an aluminium compound, such as aluminium sulphate or polyaluminium sulphate, for precipitation of interfering substances, such as oxygen-demanding organic material and metals, that the precipitated material is removed from the filtrate, that the aluminium content of the filtrate after precipitation of interfering substances is adjusted to at most 20 ppm, and that the filtrate is then recirculated to the peroxide bleaching step. By the method, a reduced consumption of hydrogen peroxide in the peroxide bleaching step is achieved.
    Type: Grant
    Filed: September 15, 2000
    Date of Patent: June 8, 2004
    Assignee: Kemira Kemi AB
    Inventors: Hans Terelius, Anette Olsson, Margareta Nilsson, Jessica Svensson, Christos Rampotas
  • Publication number: 20040089430
    Abstract: A continuous, alkaline process for the production of pulp from wood chips, wherein the preheated chips are subjected to an extended impregnation step for at least 60 min, preferably longer, at a temperature not exceeding the impregnation liquor boiling point at atmospheric conditions, and a rapid heating and cooking period of less than 65 min, preferably shorter, followed by cooling to below reaction temperature. Fresh alkali is added both during impregnation and the heating/cooking period.
    Type: Application
    Filed: December 18, 2003
    Publication date: May 13, 2004
    Inventors: Thomas Fant, Mikael Svedman, Lari Lammi
  • Patent number: 6663749
    Abstract: A method is provided for the use of borates in the recausticization of alkali-containing liquors such as those produced in the chemical and semi-chemical pulping of wood and in the oxidation and bleaching of wood pulp. Sodium hydroxide is regenerated from sodium carbonate-containing smelts in such pulp processes by autocausticization through the addition of limited amounts of borate. Autocausticization may be carried out at boron to carbonate molar ratios below 2:1 and at sodium to boron molar ratios exceeding 3:1, resulting in high reaction efficiency. Partial autocausticization using borate may also be combined with conventional lime recausticization for the regeneration of sodium hydroxide from sodium carbonate-containing smelts.
    Type: Grant
    Filed: September 25, 2001
    Date of Patent: December 16, 2003
    Assignee: U.S. Borax Inc.
    Inventors: Charles M. Bair, Robert B. McBroom, Honghi N. Tran
  • Publication number: 20030145961
    Abstract: The invention relates to a process for treating bleaching liquors from pulping processes based on organic acids. The process is characterized in that inorganic acid such as nitric acid, phosphoric acid and/or sulphuric acid, is added into a bleaching liquor obtained from the bleaching or a stage closely associated with bleaching, whereby organic acids contained in the bleaching liquor are released into the bleaching liquor. The organic acids are then separated from the bleaching liquor and recycled to the cooking stage to be used as cooking chemicals. The nitrogen-, phosphor- and/or sulphur-containing product thereby produced, from which organic acids have been separated, is recovered to be used as a fertilizer or as raw material for a fertilizer.
    Type: Application
    Filed: November 15, 2002
    Publication date: August 7, 2003
    Inventors: Pasi Rousu, Paivi Rousu, Esa Rousu, Juha Anttila
  • Patent number: 6562191
    Abstract: A process based on formic acid cooking for producing pulp from herbaceous plants and deciduous trees by using acetic acid as an additional cooking chemical. The obtained pulp can be used in fine paper and board production as short-fibered material, for instance. The invention also relates to a process for adjusting the hemicellulose content of the pulp in connection with the formic acid cooking by using acetic acid as an additional cooking chemical.
    Type: Grant
    Filed: November 3, 2000
    Date of Patent: May 13, 2003
    Assignee: Chempolis Oy
    Inventors: Pasi Rousu, Päivi Rousu, Esa Rousu
  • Patent number: 6544384
    Abstract: The strength properties of chemical cellulose pulp (particularly kraft pulp) are improved by substituting a cold impregnation soak for conventional impregnation procedures. After steaming, wood chips are soaked in an alkaline liquid at a temperature of about 80-110° C. (preferably 80-100° C., or 90-105° C.) for between one-half-72 hours (typically about 2-4 hours) at a pressure of about 0-15 bar (preferably about 1-5 bar), to dissolve at least about 8% of the wood (preferably about 10-20%) and at least about 15% of the lignin. The alkaline liquid used preferably contains sulfide (e.g. black liquor, green liquor, white liquor, or mixtures thereof), but almost any alkaline liquid having an alkali concentration of about 1.0 mole of NaOH/liter or less (typically about 0.75 m/l or less) is suitable. The wood chips are then raised to a cooking temperature of about 145-180° C. and cooked to produce the cellulose chemical pulp.
    Type: Grant
    Filed: October 15, 2001
    Date of Patent: April 8, 2003
    Assignee: Andritz Inc.
    Inventors: Kaj O. Henricson, Aki Hannu Vilpponen, Hannu Olavi Ramark, Auvo Kimmo Kettunen, C. Bertil Stromberg
  • Patent number: 6468390
    Abstract: A method for continuous cooking of lignocellulosic fiber material, comprising the steps of sequentially (a) in a first stage, impregnating the fiber material in an impregnation liquid comprising alkali metal hydroxide, and thereafter withdrawing (14, 514) a spent impregnation liquid; (b) in a second stage, cooking the fiber material in a cooking liquor comprising alkali metal hydroxide; and (c) in a third stage, adding (A), to said fiber material, a liquid which is rich in hemicellulose, said liquid preferably comprising at least a part (14a, 514a) of said withdrawn spent impregnation liquid. In a fourth stage (d), the fiber material is cooked in a cooking liquor comprising the liquid added in the third stage, whereby the fiber material is subjected to a retention time of at least 1 hour in said fourth stage.
    Type: Grant
    Filed: August 24, 1998
    Date of Patent: October 22, 2002
    Assignee: Kvaerner Pulping AB
    Inventors: Vidar Martin Snekkenes, Krister Karl Erik Olsson, Bror Lennart Gustavsson, Ernst Mikael Lindström
  • Publication number: 20020088568
    Abstract: A method is provided for the use of borates in the recausticization of alkali-containing liquors such as those produced in the chemical and semi-chemical pulping of wood and in the oxidation and bleaching of wood pulp. Sodium hydroxide is regenerated from sodium carbonate-containing smelts in such pulp processes by autocausticization through the addition of limited amounts of borate. Autocausticization may be carried out at boron to carbonate molar ratios below 2:1 and at sodium to boron molar ratios exceeding 3:1, resulting in high reaction efficiency. Partial autocausticization using borate may also be combined with conventional lime recausticization for the regeneration of sodium hydroxide from sodium carbonate-containing smelts.
    Type: Application
    Filed: January 25, 2001
    Publication date: July 11, 2002
    Inventors: Charles M. Bair, Robert B. McBroom, Honghi N. Tran
  • Publication number: 20020046819
    Abstract: A method for obtaining particulate calcium carbonate having an average particle size less than about 12 microns is provided. The method includes the steps of (1) withdrawing from a pulp mill a mixture containing calcium carbonate; (2) treating the mixture to remove contaminants contained in the mixture to produce a treated mixture containing calcium carbonate and further having a chemical composition and/or purity which substantially inhibits the fusing together of calcium carbonate particulates; (3) recovering from the treated mixture particulate calcium carbonate having an average particle size less than about 12 microns. The calcium carbonate produced has a high surface area to volume ratio and is therefore highly reactive and suitable for numerous applications such as in the treatment of soil, filler paper production, paint production, and contaminant containment in coal stack emission assemblies.
    Type: Application
    Filed: December 18, 2001
    Publication date: April 25, 2002
    Inventors: Gary Allen Olsen, John Carl Stuever, Susan Candace Stuever
  • Patent number: 6348128
    Abstract: A method is provided for improving causticizing efficiency in the conventional lime recausticization portion of an alkaline pulping process. Such processes are commonly used in the pulping and bleaching of wood and non-wood cellulose fiber materials. The method of this invention comprises reacting an aqueous solution of sodium carbonate with lime to produce sodium hydroxide (causticization) in the presence of borate in order to improve the causticization reaction efficiency. Borate is added in an amount sufficient to provide a boron to sodium (B/Na) molar ratio in the range of between about 0.001:1 and 0.4:1, and preferably in the range of between about 0.01:1 and 0.3:1, which results in an increased causticization efficiency of up to 8% over the reaction efficiency obtained in the absence of borate.
    Type: Grant
    Filed: March 24, 1999
    Date of Patent: February 19, 2002
    Assignee: U.S. Borax Inc.
    Inventors: Honghi N. Tran, Charles M. Bair, Robert B. McBroom
  • Patent number: 6315861
    Abstract: A method for conditioning an ozone gas recycle stream in an ozone pulp bleaching process. The method includes the steps of providing an oxygen containing feed gas to an ozone generator; generating ozone from said feed gas to produce an ozone rich oxygen gas; bleaching pulp with said ozone rich gas, thereby producing an exhaust gas containing contaminants including carbon dioxide and entrained pulp fibers; removing at least some of said contaminants by at least removing entrained pulp fibers from the exhaust gas to produce a recycle gas; directing said recycle gas into the ozone generator to provide at least a portion of said oxygen containing feed gas; and removing carbon dioxide during said contaminant removal step in an amount sufficient to a level of about 6 wt. wt. % to thus allow operation of the ozone generator at or approaching full capacity.
    Type: Grant
    Filed: August 31, 2000
    Date of Patent: November 13, 2001
    Assignee: Union Camp Patent Holding, Inc.
    Inventors: James Joseph, Michael A. Pikulin, William H. Friend
  • Patent number: 6294048
    Abstract: A method is provided for the use of borates in the recausticization of alkali-containing liquors such as those produced in the chemical and semi-chemical pulping of wood and in the oxidation and bleaching of wood pulp. Sodium hydroxide is regenerated from sodium carbonate-containing smelts in such pulp processes by autocausticization through the addition of limited amounts of borate. Autocausticization may be carried out at boron to carbonate molar ratios below 2:1 and at sodium to boron molar ratios exceeding 3:1, resulting in high reaction efficiency. Partial autocausticization using borate may also be combined with conventional lime recausticization for the regeneration of sodium hydroxide from sodium carbonate-containing smelts.
    Type: Grant
    Filed: January 28, 1999
    Date of Patent: September 25, 2001
    Assignee: U.S. Borax Inc.
    Inventors: Charles M. Bair, Robert B. McBroom, Honghi N. Tran
  • Patent number: 6261413
    Abstract: The present invention relates to a process for continuously guiding a liquid when digesting pulp in a digester, wherein liquid used in a process step can circulate between containers or tanks arranged at the inflow and outflow side of the digester and when this particular process step has been reached, the digester is connected into the circulation between the containers or tanks associated with the process step.
    Type: Grant
    Filed: April 3, 1997
    Date of Patent: July 17, 2001
    Assignee: Impco-Voest-Alpine Pulping Technologies GmbH
    Inventor: Manfred Dietmar Hepp
  • Patent number: 6210527
    Abstract: A method for producing bleached wood pulp in which wood chips are digested in polysulfide liquor to produce brown stock pulp. The brown stock pulp is washed to produce washed brown stock wood pulp and weak black liquor and the washed wood pulp is then delignified in an oxygen delignification stage to produce oxygen delignified wood pulp. The delignified wood pulp is then ozone bleached in an ozone bleaching stage in which a waste stream principally containing ozone, carbon dioxide and oxygen is produced. The ozone-bleached pulp is introduced into an extractive oxidation stage which can include peroxide to further bleach the pulp and the product of the extractive oxidation stage is then either introduced into either a peroxide or chlorine dioxide bleaching stage.
    Type: Grant
    Filed: March 14, 1994
    Date of Patent: April 3, 2001
    Assignee: The BOC Group, Inc.
    Inventors: Mark J. Kirschner, Rustam H. Sethna
  • Patent number: 5993601
    Abstract: The invention relates to a process for producing polysulphide by means of oxidizing sulphide in spent liquors from kraft cellulose cooking. The process is characterized in that green liquor is firstly enriched in sulphide and then oxidized.
    Type: Grant
    Filed: January 21, 1998
    Date of Patent: November 30, 1999
    Assignee: Kvaerner Pulping AB
    Inventors: Olle Wennberg, Martin Wimby
  • Patent number: 5944951
    Abstract: A method for reusing spent gas from an ozone bleaching reactor includes steps for removing lint from the spent gas, compressing it, passing it through a reactor in which hydrocarbons and carbon monoxide are destroyed by oxidation, and cooling the gas. Injecting the gas together with compressed air into a mist separator for removal of any mist from the gas and then passing the gas through a pressure swing adsorption device in which nitrogen, carbon dioxide, trace water vapor, and other trace elements may be removed by adsorption on a molecular sieve material. The recycled gas is fed to an ozone generator and from there to an ozone/pulp bleaching reactor. By appropriate selection and layering of molecular sieve materials in the pressure swing adsorption device, it is possible to provide selective removal of a variety of gaseous elements from a gas stream.
    Type: Grant
    Filed: September 26, 1997
    Date of Patent: August 31, 1999
    Assignees: Ingersoll-Rand Company, Beloit Technologies, Inc.
    Inventor: Shusuke Minami
  • Patent number: 5938892
    Abstract: A process for bleaching wood pulp is provided comprising subjecting the wood pulp, after brown stock washing, to an oxygen delignification stage, a washing sequence, a first chlorine dioxide bleaching stage, an oxidative extraction stage, at least one final chlorine dioxide bleaching stage and then recycling the filtrate from the oxidative extraction stage countercurrently through the bleaching plant and brown stock washing. Additionally, and quite beneficially, the filtrate from the first chlorine dioxide bleaching stage is also recycled countercurrently through the brown stock washing thereby significantly reducing the environmental impact associated with the manufacture of bleach wood pulp.
    Type: Grant
    Filed: April 8, 1994
    Date of Patent: August 17, 1999
    Assignee: Champion International Corporation
    Inventors: Gerald E. Maples, Raman Ambady
  • Patent number: 5853535
    Abstract: A process for bleaching wood pulp is provided comprising subjecting the wood pulp, after brown stock washing, to an oxygen delignification stage, a washing sequence, a first chlorine dioxide bleaching stage, an oxidative extraction stage, optionally at least one final chlorine dioxide bleaching stage and then recycling the filtrate from the oxidative extraction stage counter-currently through the bleaching plant and brown stock washing. Additionally, and quite beneficially, the filtrate from the first chlorine dioxide bleaching stage is also recycled counter-currently through the brown stock washing thereby significantly reducing the environmental impact associated with the manufacture of bleach wood pulp.
    Type: Grant
    Filed: November 7, 1994
    Date of Patent: December 29, 1998
    Assignee: Champion International Corporation
    Inventors: Gerald E. Maples, Joseph R. Caron, John A. Fleck
  • Patent number: 5788813
    Abstract: A method and apparatus for treating green liquor from a sulphate pulp mill enhances the clarification of the green liquor and may easily be integrated into existing pulp mills. A first portion of the green liquor from the sulphate pulp mill is clarified in a clarifier to produce a clarified green liquor and a dregs-containing green liquor. The dregs-containing green liquor is filtered in a green liquor filter to produce filtrate and dregs. The filtrate is combined) with the clarified green liquor to produce a first combined stream; and the dregs are filtered in a dregs filter. A second portion of green liquor from the sulphate pulp mill is combined with the dregs-containing green liquor to produce a second combined stream, and the second combined stream is introduced into the green liquor filter. The dregs from step (b) are washed prior to filtering the dregs, the green liquor filter and washer comprising a single structure.
    Type: Grant
    Filed: September 11, 1996
    Date of Patent: August 4, 1998
    Assignee: Ahlstrom Machinery Oy
    Inventors: Holger Engdahl, Martti Pokkinen, Pekka Tormikoski
  • Patent number: 5779856
    Abstract: Chemical (typically kraft) pulp having enhanced intrinsic fiber strength and bleachability compared to pulp produced using conventional or modified kraft cooking is produced by using high alkali and/or pH cooking, preferably by adding the vast majority of cooking liquor (such as kraft white liquor) after the first removal of liquid from the digester so that the effective alkali concentration is high near the end of the cook. That is during at least the last minute (preferably at least the last 15 minutes and most preferably at least the last 30 minutes) before the cook is terminated the effective alkali concentration is between 15-50 g/l, more preferably between about 18-40 g/l, and most preferably between about 20-35 g/l.
    Type: Grant
    Filed: October 24, 1996
    Date of Patent: July 14, 1998
    Assignee: Ahlstrom Machinery Inc.
    Inventor: Auvo K. Kettunen
  • Patent number: 5688367
    Abstract: A method and installation for bleaching a lignocellulosic pulp with ozone, while recovering an oxygen-rich gas which may be recycled or re-used. Bleaching of the pulp with ozone is preferably carried out under conditions in which ingress of air is prevented. In a multi-step bleaching process, an oxygen-rich vent gas typically containing at least 90%, by weight, of oxygen may be recovered from a second contactor for potential use in different oxygen-consuming operations in a pulp mill.
    Type: Grant
    Filed: December 11, 1995
    Date of Patent: November 18, 1997
    Assignee: Canadian Liquid Air/Air Liquide Canada LTEE
    Inventors: Derek Hornsey, Gordon H. Homer, John R. Ayton
  • Patent number: 5676795
    Abstract: The present invention relates to a process for producing viscose pulp from lignocelluloses, such as hardwood, softwood or annual plants, in which process the lignocellulose is treated in a digester at first with saturated steam to prehydrolyze hemicelluloses and subsequently, without flashing, with hot black liquor (HSL) of a preceding sulfate pulp digestion as well as, if desired, under addition of fresh white liquor (WL) to neutralize the acidic reaction products formed, neutralization liquor (NL) thus being formed in the digester. Upon addition of the amount of alkali required for delignification in the form of fresh white liquor (WL), if desired, in combination with a displacement of neutralization liquor (NL) and temperature adjustment, digestion then will take place with or without temperature gradient.
    Type: Grant
    Filed: July 13, 1995
    Date of Patent: October 14, 1997
    Assignees: Voest-Alpine Industrieanlagenbau GmbH, Lenzing Aktiengesellschaft
    Inventors: Wolfgang Wizani, Andreas Krotscheck, Johann Schuster, Karl Lackner
  • Patent number: 5645728
    Abstract: A method of recovering hydrogen peroxide from colored aqueous solutions is disclosed. The solution is brought in contact with a non-ionic size-exclusion chromatography resin made up of packed particles having narrow, low molecular weight pores. The higher molecular weight colored constituents are largely excluded from the pores causing these constituents to be more rapidly eluted with water along the exterior of the particles. Hydrogen peroxide molecules are small enough to enter the pores several times in their passage through the resin which slows their progress sufficiently to cause elution of hydrogen peroxide after the colored constituents have been eluted, effectively resolving the two components.
    Type: Grant
    Filed: May 1, 1995
    Date of Patent: July 8, 1997
    Assignee: University of Victoria Innovation and Development Corporation
    Inventors: Martin Blake Hocking, David John Herbert
  • Patent number: 5639347
    Abstract: A method and apparatus facilitate removal of metals from acidic liquids containing dissolved metals (such as pulp mill bleach plant washer filtrate) by oxidizing the liquid with ozone, hydrogen peroxide, oxygen, and/or air to increase the valence of the metals (like Mn and Fe) so that they become easier to precipitate. Oxidation may be practiced using any suitable reactor, such as a gas-contact reactor, or a plunger type reactor where the oxidizing agent is primarily gaseous, or a static mixer or stirred tank where the oxidizing agent is primarily liquid. After oxidation the pH of the liquid is adjusted (e.g. to over 6, preferably about 8-11) to precipitate the metals. The precipitated metals are then removed by filtration, sedimentation or flotation, and the metals-depleted liquid used elsewhere in the pulp mill.
    Type: Grant
    Filed: August 31, 1993
    Date of Patent: June 17, 1997
    Assignee: Ahlstrom Machinery Inc.
    Inventor: Hans G. Lindberg
  • Patent number: 5635026
    Abstract: Chemical (typically kraft) pulp having enhanced intrinsic fiber strength and bleachability compared to pulp produced using conventional or modified kraft cooking is produced by using high alkali and/or pH cooking. After being impregnated with a first cooking liquor (e.g. white liquor) having low effective alkali, the first liquor is extracted from the pulp, and it is impregnated with a second cooking liquor having an effective alkali concentration of at least 25 g/l and cooked at cooking temperature (e.g. 140.degree.-190.degree. C.) to produce a spent second cooking liquor having a residual effective alkali concentration of at least about 15 g/l, which is then extracted from the pulp. The spent second liquor may be used to preheat incoming white liquor, and then flashed and used as the first liquor. The pH of the first liquor is typically less than about 13.0, and the residual pH of the spent second liquor is about 13.0 or more.
    Type: Grant
    Filed: November 13, 1995
    Date of Patent: June 3, 1997
    Assignee: Ahlstrom Machinery Inc.
    Inventors: Auvo K. Kettunen, Kaj O. Henricson, Aki H. Vilpponen, Jian E. Jiang, Bruno S. Marcoccia
  • Patent number: 5562830
    Abstract: A method of inhibiting corrosion and scale formation and deposition in aqueous systems by adding a combination of a polyepoxysuccinic acid or salts thereof and a phosphonocarboxylic acid or salts thereof.
    Type: Grant
    Filed: September 14, 1995
    Date of Patent: October 8, 1996
    Assignee: Betz Laboratories, Inc.
    Inventors: Davor F. Zidovec, Preetha M. Prabhu
  • Patent number: 5509999
    Abstract: The removal of bleaching chemical-consuming metals from treatment fluids in a cellulose pulp mill is facilitated by treating the pulp in an acidic or neutral stage to dissolve metals, washing or thickening the pulp to produce a filtrate containing dissolved metals, and then using an alkali liquid to adjust the pH of the filtrate to cause dissolved metals to precipitate. The alkali liquid is pretreated with carbon dioxide to reduce the sulfide content and increase the carbonate content thereof, preferred alkali liquids being green liquor and white liquor. The reduced-metal content filtrate is used in the bleach plant of the pulp mill, to make bleaching chemicals, as a wash liquid, etc. Treatment of the alkali liquid with carbon dioxide is typically practiced by scrubbing the liquor with carbon dioxide gas, for example, using a plate column scrubber or a stationary packing scrubber.
    Type: Grant
    Filed: February 14, 1994
    Date of Patent: April 23, 1996
    Assignee: Kamyr, Inc.
    Inventor: Hans G. Lindberg
  • Patent number: 5472567
    Abstract: A number of different, efficient treatments of slurries and liquid with gas can be provided. A slurry or liquid is introduced into a first end of a vortex. A gas--such as a chemically reactive gas--is introduced from exteriorly of the vortex into contact with the slurry or liquid in the vortex, so that a desired reaction between the slurry or liquid and the gas takes place. The treated slurry or liquid is removed from the second end of the vortex while any residual or carrier gas is removed from the first end of the vortex. Gas introduction is preferably accomplished through a porous surface of revolution (e.g. cylindrical or conical) wall surrounding the vortex, the gas being in minute bubble form when it enters the slurry or liquid.
    Type: Grant
    Filed: December 15, 1994
    Date of Patent: December 5, 1995
    Assignee: Kamyr, Inc.
    Inventor: Louis O. Torregrossa
  • Patent number: 5468393
    Abstract: A method of inhibiting scale formation in acidic aqueous systems where metal ions such as Al.sup.+3 and Fe.sup.+3 are present by employing a polyepoxysuccinic acid in combination with a metal ion binding material.
    Type: Grant
    Filed: October 20, 1994
    Date of Patent: November 21, 1995
    Assignee: Betz PaperChem, Inc.
    Inventors: Davor F. Zidovec, Alexander D. Fisher, deceased
  • Patent number: 5407583
    Abstract: An anionic/cationic polymer mixture comprising:(a) a polyanion selected from polyacrylic acid, polymethacrylic acid, and polymaleic anhydride, each optionally copolymerized with each other, or optionally copolymerized with acrylamide up to a molar unit ratio of 1:1, provided that the total polyanionic weight average molecular weight is from about 1 to 5 thousand, and(b) the polycation poly(dimethyldiallylammonium chloride) having a weight average molecular weight of from about 25 thousand to 1 million,wherein the weight ratio of polyanion (a) to polycation (b) is from 1:2 to 1:8, has been found to give excellent inhibition of the formation, deposition and adherence of various alkali metal and alkaline earth metal scales, e.g., sodium sulfate, sodium carbonate and calcium carbonate scales in the stringent conditions which characterize black liquor heaters, evaporators, etc.
    Type: Grant
    Filed: July 15, 1993
    Date of Patent: April 18, 1995
    Assignee: Calgon Corporation
    Inventors: Jasbir S. Gill, Kenneth F. Henderson
  • Patent number: 5405497
    Abstract: A slurry or liquid is introduced into a first end of a vortex. A gas--such as a chemically reactive gas--is introduced from exteriorly of the vortex into contact with the slurry or liquid in the vortex, so that a desired reaction between the slurry or liquid and the gas takes place. The treated slurry or liquid is removed from the second end of the vortex while any residual or carrier gas is removed from the first end of the vortex. Gas introduction is preferably accomplished through a porous surface of revolution (e.g. cylindrical or conical) wall surrounding the vortex, the gas being in minute bubble form when it enters the slurry or liquid. This has particular applicability in the treatment of paper pulp using an ozone containing gas, or in reacting various liquids in the paper and pulp industry with gas (such as reaction of caustic solutions with chlorine or chlorine dioxide gas), the stripping of a strippable component from a liquid (e.g.
    Type: Grant
    Filed: August 28, 1990
    Date of Patent: April 11, 1995
    Assignee: Kamyr, Inc.
    Inventor: Louis O. Torregrossa
  • Patent number: 5403441
    Abstract: A method for controlling the gas recycle loop of an ozone bleaching process wherein an ozone generator produces an ozone containing gas from an oxygen containing feed gas and delivers the ozone containing gas to an ozone reactor at a variable flow rate responsive to reactor ozone demand. Pulp is bleached with the ozone containing gas, thereby producing an exhaust gas having a flow rate that varies in response to the flow rate of the ozone containing gas delivered to the ozone reactor. The exhaust gas is then recovered and its flow rate is modified within the recycle loop so that an amount equivalent to reactor ozone demand is returned to the ozone generators. The oxygen content of the oxygen containing feed gas is monitored at or near the inlet of the ozone generator and an amount of fresh oxygen is supplied to the oxygen containing feed gas to obtain a predetermined level of oxygen therein.
    Type: Grant
    Filed: November 13, 1992
    Date of Patent: April 4, 1995
    Assignee: Union Camp Patent Holding, Inc.
    Inventor: George W. McDonald
  • Patent number: 5401362
    Abstract: Transition metals are removed from cellulose pulp and treatment fluids in a pulp mill. Medium consistency digested pulp is treated in an acidic stage, and then washed to produce a filtrate. The pH of at least a substantial part of the filtrate is adjusted so that it is greater than 9 (preferably greater than 10.5), while a sufficient carbonate content is provided to keep the calcium content low. Adjusting the pH causes dissolved transition metals in the filtrate to precipitate as solids, and the solids can then be filtered out, e.g. by precoat filtering, or clarification followed by polishing filtering. The greatly reduced transition metal content filtrate is then used elsewhere in the pulp mill, as in a washer following an oxygen delignification stage. The acidic stage may be an EDTA stage, an ozone stage, an acid only stage, etc., and the pulp is preferably treated so that it is bleached in at least one Z stage and one P stage, and preferably also an E (e.g. E.sub.op) stage.
    Type: Grant
    Filed: March 24, 1993
    Date of Patent: March 28, 1995
    Assignee: Kamyr, Inc.
    Inventor: Hans G. Lindberg
  • Patent number: 5368740
    Abstract: A method of inhibiting scale formation in acidic aqueous systems where metal ions such as A1.sup.+3 or Fe.sup.+3 are present by employing a polyepoxysuccinic acid in combination with a metal ion binding material.
    Type: Grant
    Filed: April 23, 1993
    Date of Patent: November 29, 1994
    Assignee: Betz PaperChem, Inc.
    Inventors: Davor F. Zidovec, Alexander D. Fisher
  • Patent number: 5352332
    Abstract: A process for bleaching wood pulp is provided comprising subjecting the wood pulp, after brown stock washing, to an oxygen delignification stage, a washing sequence, a first chlorine dioxide bleaching stage, an oxidative extraction stage, at least one final chlorine dioxide bleaching stage and then recycling the filtrate from the oxidative extraction stage countercurrently through the bleaching plant and brown stock washing. Additionally, and quite beneficially, the filtrate from the first chlorine dioxide bleaching stage is also recycled countercurrently through the brown stock washing thereby significantly reducing the environmental impact associated with the manufacture of bleach wood pulp.
    Type: Grant
    Filed: September 14, 1992
    Date of Patent: October 4, 1994
    Inventors: Gerald E. Maples, Raman Ambady
  • Patent number: 5328564
    Abstract: Kraft pulp is bleached to a brightness of about 90 CPPA or greater, without the use of chlorinated organic compounds that has commercially acceptable strength properties. During production of the kraft pulp it is subjected to extended delignification, by adding kraft white liquor to a first recirculation loop in the digester, and/or a second, wash, recirculation loop in the digester; or by conventional pulping followed by two oxygen stages, with washing between the stages. The extended delignification pulp is then subjected to ozone bleaching, with an ozone dosage of less than 1.0% (preferably less than about 0.5%). The ozone bleaching sequence may be a (ZE)P(ZE)P sequence.
    Type: Grant
    Filed: February 18, 1992
    Date of Patent: July 12, 1994
    Assignee: Kamyr, Inc.
    Inventors: Jian E. Jiang, Brian F. Greenwood, Joseph R. Phillips
  • Patent number: 5246542
    Abstract: The invention disclosed here is a process or system for treating the effluent from a BCTMP pulp mill. The effluent is evaporated to produce a water condensate and a remaining waste product concentrate. The condensate is recycled for use in the BCTMP mill, or is dumped into the environment. The concentrate is incinerated in a recovery boiler. Incineration results in the recovery of certain reusable chemicals. At least some of such chemicals are fed back into the effluent while it is being evaporated, to buffer it, and thereby prevent the carryover of undesirable organic acids into the condensate. This ensures sufficient condensate purity for recycling it in the BCTMP process, or for otherwise dumping it into the environment.
    Type: Grant
    Filed: September 18, 1991
    Date of Patent: September 21, 1993
    Inventors: Theodore M. Fosberg, Johan H. Jansen
  • Patent number: 5174860
    Abstract: A kraft black liquor recovery system utilizing three separate reactors for liquor pyrolysis, sulfate reduction and carbon plus organics combustion, respectively. Oxidized black liquor is pyrolyzed in a fluid bed reactor. The temperature in the fluid bed reactor is 600.degree. C. or lower. The resulting char, containing Na.sub.2 CO.sub.3 and Na.sub.2 SO.sub.4 and a significant amount of carbon, is separated from the pyrolysis gases and introduced in an indirect heated reactor where reduction of Na.sub.2 SO.sub.4 to Na.sub.2 S takes place in the solid state under an atmosphere generated by the reduction. The reduced char is cooled and leached to produce green liquor. The leached char and gases from the pyrolysis and reduction reactors are burned in a fluid bed combustion unit operating below the melting point of mixtures of Na.sub.2 CO.sub.3 and Na.sub.2 SO.sub.4. The fluid bed particles, consisting mainly of Na.sub.2 CO.sub.3 and Na.sub.2 SO.sub.
    Type: Grant
    Filed: November 8, 1989
    Date of Patent: December 29, 1992
    Inventors: Adriaan R. P. van Heiningen, Jian Li, John Fallavollita
  • Patent number: 5127992
    Abstract: A process is provided for the treatment of an acidic aqueous effluent derived from a chlorine or chlorine compound bleaching process. The acidic effluent is reacted with a neutralizing base selected from carbonates, hydroxides and oxides of Al, Cr, Co, Fe, Mg, Mn, and Ni. The neutralized effluent is concentrated and residual base and HCl are subsequently recovered. The concentration of neutralized effluent may be accomplished by passing the neutralized effluent through the cooling tower of the pulp mill.
    Type: Grant
    Filed: August 23, 1989
    Date of Patent: July 7, 1992
    Assignee: Sappi Limited
    Inventors: Christopher J. Davies, Volkmar J. Bohmer, Michael D. Birkett
  • Patent number: 5082526
    Abstract: Sodium sulfide or hydrosulfide is oxidized to produce sodium polysulfide and sodium hydroxide. Under appropriate conditions, the oxidation may be pursued further to convert all the sodium sulfide into sodium thiosulfate. The oxidation is carried out at or above atmospheric pressure in a mixed reactor or in a pipeline reactor, by sparging oxygen or air, in a mixture of white liquor and lime mud particles produced in the recausticizing plant of a kraft mill.
    Type: Grant
    Filed: April 5, 1990
    Date of Patent: January 21, 1992
    Assignee: Pulp and Paper Research Institute of Canada
    Inventor: Gilles Dorris