Abstract: A method to enhance brightness in Chemical and Mechanical pulps comprising adding an organic sulfide chelant is described and claimed. A method to enhance delignification in a Chemical pulp comprising adding an organic sulfide chelant is also described and claimed.

Abstract: In accordance with the present invention, lyocell products can be made with unbleached pulps resulting in products with high amounts of hemicellulose and high amounts of lignin as compared to conventional lyocell products. The lyocell products of the present invention are advantageously less expensive to produce but retain the desirable strength of conventional lyocell products.

Abstract: A lignocellulose material is cooked by means of an alkaline cooking liquor containing polysulfides in the presence of a quinone-hydroquinone compound, of which the oxidation-reduction potential in the form present during the cooking, which potential is a value calculated as a standard oxidation-reduction potential (Ea) with a hydrogen ion activity of 1, is within a range of from 0.12 to 0.25V to the standard hydrogen electrode potential. It is thereby possible to cook the lignocellulose material with a low Kappa number and in good yield and at the same time, to reduce the amount of the chemical solution used and to reduce the load on a recovery boiler.

Abstract: A process for peroxide bleaching of mechanical or high yield pulp, the process comprising adding to a pulp slurry at least one stabilizer for stabilizing low valency states of transition metal ions in the slurry; subsequently adding caustic soda to said slurry simultaneously with or subsequent to adding said at least one stabilizer; adding hydrogen peroxide to the slurry at a preselected point; and subjecting the slurry to preselected conditions to complete the bleaching process.

Abstract: Xylooligosaccharide is produced from a lignocellulose pulp by enzyme-treating a lignocellulose pulp with hemicellulase, filtering the resultant reaction mixture to separate a liquid fraction from the enzyme-treated pulp, subjecting the separated liquid fraction to a permeation treatment through a separation membrane to separate a non-permeated fraction containing xylooligosaccharide-lignin complex with an increased concentration from a permeated fraction, collecting the non-permeated fraction, and separating and recovering xylooligosaccharide from the collected non-permeated fraction.

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.

Abstract: Chemical species (e.g., metaborate, carbonate, hydroxide and sulfide) in a boron-containing alkaline wood pulping liquor sample are determined quantitatively by (i) subjecting a first aliquot portion of the sample to a primary acid titration analysis to derive multiple equivalence points at different respective pH values; (ii) subjecting a second aliquot portion of the sample to an analysis to determine the quantitative presence of boron or sulfide ions therein, and then (iii) determining the quantitative presence in the sample of at least one of the chemical species. Wood pulping parameters may thus be determined on the basis of the quantitative presence of the chemical species to assist in process and/or quality control of the wood pulping operation.

Abstract: In accordance with the present invention, lyocell products can be made with unbleached pulps resulting in products with high amounts of hemicellulose and high amounts of lignin as compared to conventional lyocell products. The lyocell products of the present invention are advantageously less expensive to produce but retain the desirable strength of conventional lyocell products.

Abstract: Bleached, Kraft chemical pulp having increased hemicellulose content compared to conventional Kraft chemical pulps. In one embodiment, the pulp has a hemicellulose content greater than about 17 weight percent as measured by the 18% caustic solubility test. In another aspect, a method for making wood cellulose pulp having increased hemicellulose content compared to conventional Kraft chemical pulps. In the method, a lignocellulosic material is pulped in caustic sulfide to provide a first brownstock, which is treated with oxygen to provide a second brownstock, which is then bleached to provide the pulp product.

Abstract: Bleached, Kraft chemical pulp having increased hemicellulose content compared to conventional Kraft chemical pulps. In one embodiment, the pulp has a hemicellulose content greater than about 17 weight percent as measured by the 18% caustic solubility test. In another aspect, a method for making wood cellulose pulp having increased hemicellulose content compared to conventional Kraft chemical pulps. In the method, a lignocellulosic material is pulped in caustic sulfide to provide a first brownstock, which is treated with oxygen to provide a second brownstock, which is then bleached to provide the pulp product.

Abstract: The invention relates to a method for delignifying lignocellulosic raw materials by using sulfites in the presence of an alkaline component, especially sodium hydroxide or sodium carbonate or a mixture thereof in an aqueous solution at a high temperature and high pressure. The invention is characterized in that a first partial fragment of the alkaline component is added when the aqueous solution starts to decompose and in that at least a second partial fragment of the alkaline component is added only when delignification begins.

Abstract: A fiber cement composite material providing improved rot resistance and durability, the composite material incorporating biocide treated fibrous pulps to resist microorganism attacks. The biocide treated fibers have biocides attached to inner and outer surfaces of individualized fibers to protect the fibers from fungi, bacteria, mold and algae attacks. The biocides selected have strong affinity to cellulose and do not interfere with cement hydration reactions. This invention also discloses the formulation, the method of manufacturing and the final fiber cement products using the biocide treated fibers.

Abstract: A method to enhance brightness in Chemical and Mechanical pulps comprising adding an organic sulfide chelant is described and claimed.

Abstract: A process for bleaching substantially lignin-free pulp or paper in a single-stage bleaching process or multi-stage bleaching process; comprising contacting said substantially lignin-free pulp or paper with an aqueous reductive bleaching solution comprising hydroxymethane sulfinic acid during a reductive bleaching stage for sufficient amount of time to at least partially bleach said substantially lignin-free pulp or paper.

Abstract: Separation of dissolved and colloidal high molecular weight organic by-products from liquors or filtrates in a cellulosic pulping process to improve the overall efficiency of the process.

Abstract: An apparatus and process for solvent pulping of cellulose-containing biomass utilizes at least one steaming vessel, a plug screw feeder or compression screw device, at least one super-atmospheric impregnation vessel, a solvent delignification reactor capable of operating at a pressure of 350 psig or more, and a solvent containing line for introducing solvent-containing liquor at the plug screw feeder outlet or compression screw device outlet. The process and system can also include at least one series connected pressure diffuser and optionally a retention tube downstream of each pressure diffuser to provide sufficient retention time to substantially preclude re-deposition of lignin on the cellulose fibers of the biomass, a blow tank connected to the last of the pressure diffusers and retention tubes, and vessels for multistage alcohol washing.

Abstract: A cellulose fiber having extended biostability and the method of its manufacture are described. While prior treatments of cellulose with biotoxic metal compounds have given improved resistance to decay, these treatments have not been entirely satisfactory where the fiber had to be refined before use. Refining energy was very high and fiber length loss was substantial. Treatment of cellulose fiber with didecyldimethylammonium chloride (DDAC) or bromide (DDAB), these materials in combination with low levels of copper, or low levels of copper alone, has given a product with very good biostability without a major increase in refining energy or loss of fiber length. The treated fiber is particularly advantageous as a reinforcing component for cement board products.

Abstract: Polynuclear compounds dissolved and contained within an organic solvent are separated from the organic solvent by rendering the organic compounds insoluble within the organic solvent. Accordingly this invention removes polynuclear compounds from a saturated organic solvent. The polynuclear compounds are derived from black liquor obtained from kraft digestion. Whereby polynuclear compounds, substantially free of an organic solvent, are obtained from the organic solvent.

Abstract: Depolymerized lignins contained within black liquor are transferred to an organic solvent, soluble in organic matter and insoluble of aqueous sodium compounds contained within the black liquor. Upon separation of the aqueous sodium compounds from the organic solvent, saturated with contained depolymerized lignins, depolymerized lignins are removed from the organic solvent to result in depolymerized lignins and a separated organic solvent suitable for recycling. Resulting aqueous sodium compounds are concentrated by a multiple effect evaporator to provide liquor to digest wood chips. Whereby depolymerized lignins, substantially free from sodium compounds, are separated from a black liquor. Accordingly this invention modifies black liquor without employing a lime kiln and a recovery boiler, producing a molten smelt.

Abstract: A pulp product that has a low COD is comprised of an unbleached pulp that is soaked and washed in alkaline water for a sufficient time so that the COD after soaking and washing is less than or equal to 2.0 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 220 minutes at an elevated temperature to produce the pulp product that has a low COD.

Abstract: A chemical wood pulping process having reduced volatile organic compound emissions includes extracting wood particulates with solvent at a pressure less than 50 psi to reduce naturally-occurring particulate pitch and volatile organic compound content without significant dissolution of lignin and wood cellulosic components. The solvent used is methanol, ethanol, or acetone. This is followed by comingling the extracted wood particulates with a liquor having chemical reactants, not including the solvent used to extract the wood particulates, for solubilizing lignin. Then, allowing the chemical reactants of the liquor to react with lignin contained in the extracted wood particulates under controlled conditions of temperature and pressure for a sufficient time to solubilize and remove lignin. This is followed by producing a wood pulp having individual cellulosic fibers while releasing a reduced amount of VOCs in the wood pulping process.

Abstract: Chemical species (e.g., metaborate, carbonate, hydroxide and sulfide) in a boron-containing alkaline wood pulping liquor sample are determined quantitatively by (i) subjecting a first aliquot portion of the sample to a primary acid titration analysis to derive multiple equivalence points at different respective pH values; (ii) subjecting a second aliquot portion of the sample to an analysis to determine the quantitative presence of boron or sulfide ions therein, and then (iii) determining the quantitative presence in the sample of at least one of the chemical species. Wood pulping parameters may thus be determined on the basis of the quantitative presence of the chemical species to assist in process and/or quality control of the wood pulping operation.

Abstract: The use of low specific gravity wood from thinning operations, for example, will produce a lower brownstock viscosity for a given kappa number target. A differential of 200-cP falling ball pulp viscosity has been detected from Kraft cooks of low and high specific gravity wood. Using low specific gravity wood can reduce the bleach stage temperature and the chemical dose needed in the bleach plant to produce lyocell pulp specifications. Low specific gravity wood also increases the ability to reduce pulp viscosity to very low levels without increasing the copper number of the pulp or the concentration of carbonyl in the pulp above acceptable levels.

Abstract: A process for bleaching high bulk cellulosic fiber and producing a durable elevated curl index includes: (a) concurrently bleaching, heat treating and convolving cellulosic fiber pulp at elevated temperature and pressure at high consistency generally under conditions selected so as to preclude substantial fibrillation and attendant paper strength and fiber bonding development; and (b) recovering the pulp wherein the length weighted curl index of the treated fiber is at least about 20% higher than the length weighted curl index of the fiber prior to the heat treatment and convolving thereof. Preferably, the curl imparted to the fiber persists upon treatment for 30 minutes in a laboratory disintegrator at 3000 rpm at 1% consistency at a temperature of 125° F. Moreover, the curl may be imparted to the fiber in a disk refiner at very short residence times, on the order of several seconds or less.

Abstract: A method for producing paper pulp for use in the making of paper from eucalyptus wood chips. The method comprises inoculating wood chips with white rot fungi, fermenting the wood chips so as to cause a propagation of the fungus through the wood chips and allowing the fungus to modify the lignin, and pulping the degraded wood chips by a kraft process.

Abstract: A treatment sequence includes ozonation under acidic conditions followed by an acidic wash for enhancing the wet strength of a cellulosic fibrous material. Preferably the ozone treatment and the acidic wash are followed by a second ozonation step under acidic conditions. The fibrous cellulosic material obtained by this treatment sequence has a breaking length of at least 100 m. The wet strength of the cellulosic fibrous material is increased without the use of additives, such as wet strength agents. This use of ozone is very simple and efficient, and leads to highly pure products. The use of ozone as the only treatment chemical in particular avoids the introduction of so-called “non-process elements” (NPE) into the treatment system, for instance metal oxides such as MgO, which are frequently used in the oxidative treatment of pulps.

Abstract: There is provided a new and useful process for peroxide bleaching of mechanical or high yield pulp, the process comprising adding to a pulp slurry at least one stabilizer for stabilizing low valency states of transition metal ions in the slurry; subsequently adding caustic soda to said slurry simultaneously with or subsequent to adding said at least one stabilizer; adding hydrogen peroxide to the slurry at a preselected point; and subjecting the slurry to preselected conditions to complete the bleaching process.

Abstract: A method for preparing pulp from lignin-containing cellulosic material is disclosed, including a step for acid cleaning of the lignocellulosic material, followed by alkaline delignification. The acidic step removes undesired components such as metal ions and side groups of polysaccharides, which may have adverse effects on the process especially when extensive recycling of liquors is employed within the plant.

Abstract: The present invention relates to a process of oxidation, of the wet oxidation or ozonization type, of a liquid contained in a reactor. The gas of the gas headspace is aspirated into the liquid, and the portion which is not dissolved in the liquid is recovered in the gas headspace. The agitation means creates a flow of liquid immediately adjacent to the end of the duct opening into the liquid, and generates a gas/liquid dispersion in the zone, within which the liquid reacts with the gas, then conveys and ejects the said dispersion at its periphery, such that the gas is dissolved in the liquid in the zone extending from the agitation means to the surface of the liquid. The said process is particularly suitable for oxidations which make use of considerable quantities of oxygen or of ozone. It is particularly applied for the oxidation of papermaking liquors.

Abstract: Separation of dissolved and colloidal high molecular weight organic by-products from liquors or filtrates in a cellulosic pulping process to improve the overall efficiency of the process.

Abstract: 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.

Abstract: The production of chemical (e.g., kraft) cellulose pulp much more suited to totally chlorine free or elemental chlorine free bleaching is produced by reducing the bleaching chemical consumability of the produced pulp. The effective alkalinity of the pulp during at least the majority of the cooking stage is maintained at about 15 g/l or above (e.g., about 18-25 g/l), expressed as sodium hydroxide, so as to reduce the charged acid groups (including hexeneuronic acids) by at least 30% (e.g., at least about 50%) compared with pulp cooked at conventional alkalinity. Instead—or in addition to—the cellulosic material which produces the pulp may be heated to a temperature (at least about 100° C., preferably at least about 130° C.

Abstract: A method for producing pulp, comprising digesting lignocellulosic wood, containing one or more xylan derivatives selected from the group consisting of xylan bound with lignin, xylan bound with hexenuronic acid, and mixtures thereof, with an aqueous alkaline pulping solution containing sulfide and having an initial free hydroxyl ion concentration of at least 1 mole per liter, under conditions whereunder xylan is dissociated from said one or more xylan derivatives and the pH of the solution remains above 12.5; and then while the pH of said solution is above 12.5, adding a sufficient amount of an acidic agent to said pulping solution to precipitate dissociated xylan from said pulping solution while minimizing precipitation of lignin from said pulping solution. Carbon dioxide is a preferred acidic agent.

Abstract: Disclosed is a method for producing kraft wood fiber having an alpha-cellulose content greater than 97% and a viscosity greater than 40 centipoise. The method involves prehydrolyzing hardwood chips with water, kraft cooking, bleaching and caustic treatment. The resulting pulp can be converted to carboxymethyl cellulose superabsorbents having improved properties, particularly a high “absorbency under load”.

Abstract: A process for preparing a bleached sulfite chemical pulp includes delignification of chips of a lignocellulosic material in a sulfite pulping process until the defibration point of the material is reached, and bleaching of the fibrous material thus obtained by a chlorine-free bleaching sequence which includes at least one first bleaching step with a chlorine-free oxidant in the presence of a base. The chemical pulp prepared according to this process and paper or nonwoven made from such pulp have a high degree of brightness (at least 83% ISO) and high strength.

Abstract: The invention relates to a method of bleaching and/or delignifying cellulose, in which

Abstract: A process for final bleaching cellulose-containing pulp which has been subjected to previous bleaching with a peroxide compound. The process involves the sequential steps of exposing the pulp to an amount of a reducing agent in order to eliminate residual peroxide compound from the pulp and then final bleaching the pulp by exposing the pulp to an amount of formamidine sulfinic acid.

Abstract: A lignocellulose material is cooked by means of an alkaline cooking liquor containing polysulfides in the presence of a quinone-hydroquinone compound, of which the oxidation-reduction potential in the form present during the cooking, which potential is a value calculated as a standard oxidation-reduction potential (Ea) with a hydrogen ion activity of 1, is within a range of from 0.12 to 0.25V to the standard hydrogen electrode potential. It is thereby possible to cook the lignocellulose material with a low Kappa number and in good yield and at the same time, to reduce the amount of the chemical solution used and to reduce the load on a recovery boiler.

Abstract: A chemical wood pulping process having reduced volatile organic compound emissions includes extracting wood particulates with solvent at a pressure less than 50 psi to reduce naturally-occurring particulate pitch and volatile organic compound content without significant dissolution of lignin and wood cellulosic components. The solvent used is methanol, ethanol, or acetone. This is followed by comingling the extracted wood particulates with a liquor having chemical reactants, not including the solvent used to extract the wood particulates, for solubilizing lignin. Then, allowing the chemical reactants of the liquor to react with lignin contained in the extracted wood particulates under controlled conditions of temperature and pressure for a sufficient time to solubilize and remove lignin. This is followed by producing a wood pulp having individual cellulosic fibers while releasing a reduced amount of VOCs in the wood pulping process.

Abstract: A process for delignification and bleaching of chemically digested lignocellulose-containing pulp. In a first embodiment, the pulp is acid treated at a pH of between about 1 and about 6, whereupon a water-soluble compound containing an alkaline earth metal is added at a pH of between about 1 and about 7 before the pulp is treated with a chlorine-free bleaching agent. In a second embodiment, the acid and alkaline earth metal treatments are carried out in a single step. The chlorine-free bleaching agent includes peroxide compounds, ozone, oxygen and sodium dithionite in an optional sequence or mixture. After the treatment according to the invention, the pulp may be finally bleached to the desired brightness, suitably with a chlorine-free bleaching agent, such as ozone, to completely avoid formation and discharge of AOX.

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.

Abstract: A process for production of chemical fibrous pulp for making paper, paperboard and other fibrous products from herbaceous plants, such as kenaf. Pulp from the herbaceous plant is made by a process which involves densification of pieces of all or part of the plants; i.e., both the core and the stalk or just the core portion, into cubes or pellets having a density ranging from about 15 to about 70 lbs/ft3, preferably from about 25 to about 50 lbs/ft3, which are then chemically digested to produce a fibrous pulp. The densified cubes or pellets may be digested alone or together with conventional wood chips. A principal advantage of the invention is that the densified cubes or pellets exhibit significantly better yield and strength after treatment by conventional chemical pulping methods as compared with the undensified material, enabling more efficient and economical use of this material to supplement limited supplies of conventional hardwood and softwood pulp sources.

Abstract: The present invention is directed to an improved process for inhibiting calcium carbonate scaling in aqueous systems such as that employed in the kraft process for the production of wood pulp. Such an improved process is achieved by the addition to the system of at least one antiscalant comprising at least one monomer unit derived from the group consisting of 1,2-dihydroxy-3-butene, N-(hydroxymethyl) acrylamide, and N-(sulfomethyl) acrylamide, and at least one monomer unit derived from the group consisting of maleic acid, acrylic acid, acrylamide, methacrylic acid, itaconic acid, vinyl sulfonic acid, styrene sulfonic acid, N-tertbutylacrylamide, butoxymethylacrylamide, N,N-dimethylacrylamide, sodium acrylamidomethyl propane sulfonic acid, and salts thereof.

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.

Abstract: The present invention relates to a device and method for measuring the bleach requirement and bleachability of pulp in a pulp mill. The invention enables pulp mill operators to better control bleach plants. In one aspect, the invention comprises a system and method for rapid bleaching of the pulp, and measuring the rapid bleached brightness and lignin content of the pulp. In another aspect, the invention comprises an optical system for use in practicing embodiments of this invention.

Abstract: Kraft pulp of increased strength and bleachability may be produced with decreased consumption of effective alkali, and at a lower H factor, by keeping the dissolved organic material (DOM) concentration low substantially through the entire kraft cook, including by extracting high DOM liquid from at least one part of a continuous digester and replacing it with much lower level DOM liquid. Existing pulp mills having two-vessel hydraulic, one-vessel hydraulic, or other systems may be retrofit to provide for extractions and additions of low DOM dilution liquor (including substantially DOM-free white liquor). Also, commercial size batch digesters (8 tons per day of pulp or more) can be operated with low DOM liquor to produce increased strength pulp. Using dilution with low DOM liquor also results in reduced H factor and effective alkali consumption, and increased bleachability.

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.

Abstract: An improved pulping process by which pulp yield is increased requires using polysulfide in the cooking liquor and lignocellulosic particles having a maximum thickness of 2 mm.

Abstract: A method for impregnation and chemical digestion of lignocellulosic material and recovery of pulping liquors. A spent impregnating or cooking liquor is withdrawn and sulphurous compounds are recovered therefrom in a partial oxidation reactor. These sulphurous compounds are converted into hot liquid elemental sulphur which thereafter is mixed with a hot sulphide containing liquor to provide a polysulphide liquor with a concentration greater than 10 g/l and which is essentially free from thiosulphate. This polysulphide liquor is used for carbohydrate stabilising impregnation and/or for cooking at a relatively low temperature.

Abstract: A method of creating a number of separate product streams from an agricultural waste material, comprising: providing a starting material consisting of an agricultural waste material; hydrolyzing the starting material with an acid solution at atmospheric pressure, and temperatures not exceeding about 100.degree. C., to create an absorbent, hydrolyzed solid residue and a xylose-containing liquor; reserving the xylose-containing liquor; and delignifying the hydrolyzed solid residue with a basic solution, to create a fiber solid residue suitable for use as an absorbent material, and a dissolved lignin-containing solution.