Treatment Of Kraft Pulping Chemicals Patents (Class 162/30.11)
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Patent number: 6578529Abstract: The present invention relates to an arrangement for introducing black liquor into a furnace of a recovery boiler, said arrangement comprising an elongated tube having an interior surface and an exterior surface, through which tube the black liquor being fed into the furnace is supplied, whereby the black liquor is taken into contact with said interior surface prior to being sprayed into the furnace. The interior surface of said elongated tube is provided with heat transfer elements and surfaces, such as fins or grooves. The heat transfer element or surface increases the heat conductivity between the tube and the black liquor above the conductivity achieved with a normal tube passage.Type: GrantFiled: October 17, 2001Date of Patent: June 17, 2003Assignee: Andritz OyInventors: Antti Hytönen, Pentti Piilonen, Esa Vakkilainen
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Publication number: 20030075290Abstract: Compositions and method of improving inhibition of calcium salt scale formation under the conditions found in chemical pulp processes in which an effective amount of selected phosphonates or phosphonate blends is admixed with the black liquor composition recovered from the digester in a chemical pulping process. The compositions and method are especially well suited for use in the Kraft pulping process.Type: ApplicationFiled: June 5, 2002Publication date: April 24, 2003Inventors: Jacob Owen Thompson, Sheldon Phillip Verrett, Jeremy E. Loy, Steven John Severtson
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Publication number: 20030051841Abstract: A method and apparatus for the production of calcium carbonate and calcium silicate in common superatmospheric reactors. Multiple reactors can be provided for switching production between reactors, and advantageously utilizing process waste heat. On site production of both PCC and Calcium Silicate Hydrates is thus achieved in a paper mill.Type: ApplicationFiled: February 28, 2001Publication date: March 20, 2003Inventors: Vijay K. Mathur, Varun K. Mathur
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Patent number: 6511578Abstract: The invention relates to a method of bleaching and/or delignifying cellulose, in which (a) a sodium hydroxide solution and a peroxydisulphate solution are first of all produced by electrolysis of a sulphate, (b) the peroxydisulphate solution is converted by hydrolysis into a Caro's acid/caroate solution, (c) said Caro's acid/caroate solution is left to cool and (d) used immediately as a bleaching solution for bleaching and/or delignifying cellulose, the Caro's acid/caroate solution becoming neutralised upon introduction into the bleaching solution.Type: GrantFiled: September 21, 1999Date of Patent: January 28, 2003Assignee: Peroxid-Chemie GmbH & Co. KGInventors: Maximilian Dorn, Michael Gnann, Sven Gutewort, Werner Sebb
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Publication number: 20030010458Abstract: Compositions and method for improving inhibition of calcium salt scale formation under the conditions found in chemical pulp processes in which an effective amount of selected phosphonates or phosphonate blends is admixed with the aqueous digester composition in a chemical pulping process during the digestion stage. The compositions and method are especially well suited for use in the Kraft pulping process.Type: ApplicationFiled: June 5, 2002Publication date: January 16, 2003Inventors: Jacob Owen Thompson, Sheldon Phillip Verrett, Steven John Severtson, Jeremy E. Loy
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Patent number: 6503369Abstract: The invention relates to a process for producing cellulose and a fertilizer by-product by using a closed cycle of cooking chemicals and process waters. In the process of the invention, the pulp is bleached by at least partly using potassium hydroxide as a bleaching chemical. Thus, a bleach concentrate rich in potassium is obtained from the bleach filtrate, which bleach concentrate is combined with ashes obtained from the burning of lignin and other organic matter recovered from pulp production as a by-product, in order to be used as a potash fertilizer. The bleach-concentrate can also be used as a potash fertilizer as such. The invention also relates to a potash fertilizer obtained this way.Type: GrantFiled: October 3, 2001Date of Patent: January 7, 2003Assignee: Chempolis OyInventors: Pasi P. Rousu, Päivi P. Rousu, Esa J. Rousu
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Publication number: 20020144794Abstract: Oxidized white liquor is heat treated to increase the concentration of PSUV measured at 285 or 286 nm or PSVIS measured at 416 nm and the PSUV/PSGR or PSVIS/PSGR ratio, whereby the content of active polysulphide in the total polysulphide is increased which active polysulphide can be exploited to increase pulp yield in Kraft pulping.Type: ApplicationFiled: January 23, 2002Publication date: October 10, 2002Inventors: Ronald Peter van Heek, Gilles Marcel Dorris, Victor Charles Uloth, Natalie Page, Thomas Qinxiong Hu, Denys Francois Leclerc
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Patent number: 6451164Abstract: A process for de-watering lime mud in a Krafft pulping process is described. The process includes an improvement which comprises adding an effective water-removal rate enhancing amount of an alkyleneamine to the lime mud prior to filtration. The preferred alkyleneamine is ethyleneamine, that is, an amine having at least one —(CR2—CR2—NH—)— unit wherein each R is independently is H or an alkyl (straight-chain, branched, or cyclic) group of from about 1 to about 10 carbon atoms. Ethyleneamines include ethylenediamine, diethylenetriamine, triethylenediamine, triethylenetetramine, tetraethylenepentamine, piperazine, aminoethylpiperazine, and ethyleneamine mixtures such as mixtures of ethyleneamine oligomers having an average molecular weight of about 200-500.Type: GrantFiled: September 25, 2001Date of Patent: September 17, 2002Assignee: Huntsman Ethyleneamines LimitedInventor: Alan P. Croft
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Patent number: 6425976Abstract: The invention refers to a method for black liquor gasification in recovery boilers, of the type having a lower portion, referred to as a lower furnace and an upper portion, referred to as an upper furnace, black liquor sprayers for introduction of black liquor provided in the boiler above the lower furnace, and a number of combustion air levels, whereby the invention incorporates adding oxygen enriched air to the combustion air or directly into the lower furnace at at least one air level underneath the liquor sprayers for the purpose of creating the best possible reducing conditions in the lower furnace, redistributing from the lower furnace combustion air not needed therein following the addition of oxygen enriched air, thereby significantly reducing upward gas velocity underneath the black liquor sprayers, and introducing the redistributed combustion air in the upper furnace, thereby creating the reducing conditions and a controlled temperature in the lower furnace for emission control.Type: GrantFiled: April 16, 2001Date of Patent: July 30, 2002Assignee: AGA ABInventors: Kent K Sandquist, Anders Kullendorff
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Publication number: 20020046819Abstract: 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: ApplicationFiled: December 18, 2001Publication date: April 25, 2002Inventors: Gary Allen Olsen, John Carl Stuever, Susan Candace Stuever
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Patent number: 6348129Abstract: An aqueous stream such as pulp mill condensate containing one or more sulfur compounds is treated by (a) reacting an aqueous feed stream containing TRS contaminant selected from the group consisting of hydrogen sulfide, methyl mercaptan, dimethyl sulfide, dimethyl disulfide, and mixtures thereof, with ozone to produce a first liquid product stream and a first gaseous product stream, wherein the total amount of said one or more contaminants in said first liquid product stream is less than 1% of the amount thereof in said feed stream, and wherein said first gaseous product stream contains ozone and one or more of said contaminants; and (b) treating said first gaseous product stream with an alkaline aqueous stream to remove essentially all of said one or more contaminants from said first gaseous product stream. Preferably, a second gaseous stream produced in step (b) and containing ozone is reacted with an aqueous stream containing one or more of said contaminants, to consume all the ozone in said stream.Type: GrantFiled: April 28, 2000Date of Patent: February 19, 2002Inventors: Jorge Luiz Colodette, Philippe Charlet
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Patent number: 6319358Abstract: An electrochemical process is provided for treatment of molten kraft smelt produced from black liquor in a kraft recovery boiler. Treated smelt can be contacted with water to produce white liquor which can be re-used or recycled in the kraft process.Type: GrantFiled: January 25, 1999Date of Patent: November 20, 2001Assignees: Institue of Paper Science and Technology Inc., Georgia Tech Research CorporationInventors: Jack Winnick, Peter H. Pfromm
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Patent number: 6312560Abstract: A process for dewatering lime mud in a kraft pulping process is described. The process includes an improvement which comprises adding an effective amount of an alkyleneamine to the lime mud prior to filtration. The preferred alkyleneamine is ethyleneamine, that is, an amine having at least one —(CR2—CR2—NH—)— unit wherein each R independently is H or an alkyl (straight, branched or cyclic) group of from about 1 to about 10 carbon atoms. Ethyleneamines include ethylenediamine, diethylenetriamine, triethylenediamine, triethylenetetramine, tetraethylenepentamine, piperazine, aminoethylpiperazine, and ethyleneamine mixtures such as mixtures of ethyleneamine oligomers having an average molecular weight of about 200-500.Type: GrantFiled: July 23, 1999Date of Patent: November 6, 2001Assignee: Huntsman Ethyleneamines Ltd.Inventor: Alan P. Croft
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Patent number: 6294048Abstract: 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: GrantFiled: January 28, 1999Date of Patent: September 25, 2001Assignee: U.S. Borax Inc.Inventors: Charles M. Bair, Robert B. McBroom, Honghi N. Tran
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Patent number: 6261411Abstract: A method of recovering chemicals from spent black liquor used in a kraft pulping process comprising organic materials having oxygen containing functional groups, the method comprising heating the black liquor in the presence of lime at an elevated temperature and at a corresponding pressure at which there is no or substantially no boiling of the black liquor, until all or a portion of the oxygen is converted into carbon dioxide to form a slurry comprising microparticulate char and a white liquor suspension. The heating can be accomplished with any suitable means. For example, black liquor is evaporated in an evaporator train, and the liquor pumped in a high pressure pump to a suitable pressure, as for example, a pressure of from about 1200 psig to about 2000 psig. Thereafter, the liquor is transferred to a heat exchanger and heated to the elevated temperature, as for example a temperature of at least about 475° F.Type: GrantFiled: August 31, 2000Date of Patent: July 17, 2001Inventor: Christopher M. Roberts
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Patent number: 6228214Abstract: The invention refers to a method for black liquor gasification in recovery boilers, of the type having a lower portion, referred to as a lower furnace and an upper portion, referred to as an upper furnace, black liquor sprayers for introduction of black liquor provided in the boiler above the lower furnace, and a number of combustion air levels, whereby the invention incorporates adding oxygen enriched air to the combustion air or directly into the lower furnace at at least one air level underneath the liquor sprayers for the purpose of creating the best possible reducing conditions in the lower furnace, redistributing from the lower furnace combustion air not needed therein following the addition of oxygen enriched air, thereby significantly reducing upward gas velocity underneath the black liquor sprayers, and introducing the redistributed combustion air in the upper furnace, thereby creating the reducing conditions and a controlled temperature in the lower furnace for emission control.Type: GrantFiled: October 12, 1999Date of Patent: May 8, 2001Assignee: AGA ABInventors: Kent K Sandquist, Anders Kullendorff
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Patent number: 6183598Abstract: The invention relates to a process for recovering alkali and heat from a black liquor (5) containing silicate from a soda cook of e.g. grass, reed, straw and bagasse. In the process the black liquor (5) is treated with a gas (6) containing carbon dioxide to precipitate silica and lignin, the precipitate (9) is separated (2) from the black liquor, which is evaporated (3) and burnt (4) to generate heat and to recover a sodium carbonate melt. In the invention the black liquor (5) containing silicate is neutralised with a surplus of the gas (6) containing carbon dioxide, which preferably contains over 60% by volume of carbon dioxide. The evaporation (3) of black liquor mainly takes place after the precipitate (9) rich in silica has been separated (2).Type: GrantFiled: October 1, 1998Date of Patent: February 6, 2001Assignee: Jaako Poyry OyInventor: Bertel Myreen
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Patent number: 6168685Abstract: Concentrated black liquor formed in a kraft pulp mill process is treated to effect exothermal oxidation of black liquor solids, so as to heat the concentrated black liquor and consume a proportion of the black liquor solids. Such procedure eliminates the need to use steam to preheat black liquor and decreases the overall heating value of the concentrated black liquor, allowing an increased black liquor recovery boiler capacity to be achieved.Type: GrantFiled: October 14, 1994Date of Patent: January 2, 2001Assignee: Praxair Canada Inc.Inventor: Chris Ka Kee Ho