1826results about "Pulp bleaching" patented technology

A lyocell nonwoven fabric having fibers characterized by pebbled surfaces and variable cross sections and diameters along the fibers and from fiber to fiber, is disclosed. The lyocell nonwoven fabric is produced by centrifugal spinning, melt blowing or spunbonding. The lyocell nonwoven fabric has fibers that can be made in the microdenier range with average weights as low as one denier or less. The lyocell nonwoven fabric has fibers with low gloss, a reduced tendency to fibrillate and have enhanced dye receptivity.

Whitened fluff pulp and methods for making whitened fluff pulp. The whitened pulp is a fluff pulp that has been treated with one or more of a white pigment, a colorant, or a fluorescent whitening agent.

Disclosed is a hydrothermal treatment process for conversion of a carbon-based energy carrier material. The process comprises a step for sensitizing or activating the carbon based energy carrier material to increase its susceptibility to hydrothermal conversion. As a result of the sensitization step, the hydrothermal conversion step itself may be carried out under relatively mild conditions.

The process comprises the steps of sensitizing the carbon-based energy carrier material to increase its susceptibility to hydrothermal conversion; and subjecting the sensitized carbon-based energy carrier material to hydrothermal conversion at a temperature of less than 300 degrees centigrade in a hydrothermal treatment reactor.

The present invention relates to a method of increasing the brightness of pulp, pulp made from such methods and methods of using such pulp.

A process for bleaching mechanical wood pulp is provided comprising subjecting the wood pulp to at least one bleaching stage with one or more bleaching agents in the presence of one or more optical brightening agent, wherein the bleaching agents are selected from the group consisting of oxidative bleaching agents other than chlorine based bleaching agents such as chlorine dioxide, elemental chlorine or a combination thereof, reductive bleaching agents or any combination of two or more thereof.

An omnibus process of pulping and bleaching lignocellulosic materials in which a charge of a lignocellulosic material is biopulped and/or water extracted prior to pulping and bleaching. The lignocellulosic material may be mechanically pulped and bleached in the presence of an enzyme that breaks lignin-carbohydrate complexes. The aqueous extract in embodiments including a water extract step is separated into acetic acid and hemicellulose sugar aqueous solutions.

Cellulose containing dope is extruded through orifices and into a stream of gas moving in a direction generally parallel to the direction that the filaments are formed with varying degrees of mechanical attenuation provided to the filaments using a take-up device, such as a winder.

A process for making lyocell fibers including the steps of pulping raw material in a digester to provide an alkaline pulp, wherein the raw material includes sawdust in an amount greater than 0% up to 100%; contacting the alkaline pulp including cellulose and at least about 7% hemicellulose under alkaline conditions with an amount of an oxidant sufficient to reduce the average degree of polymerization of the cellulose to the range of from about 200 to about 1100 without substantially reducing the hemicellulose content or substantially increasing the copper number of the pulp; and forming fibers from the pulp.

The present invention provides compositions, useful for making lyocell fibers, having a high hemicellulose content, a low copper number and including cellulose that has a low average degree of polymerization (D.P.) and a narrow molecular weight distribution. Further, the present invention provides processes for making compositions, useful for making lyocell fibers, by contacting an alkaline pulp having a high hemicellulose content of at least about 7% with an oxidant sufficient to reduce the average degree of polymerization to about 200 to 1100 without substantially reducing the hemicellulose content or increasing the copper number of the pulp.

A method for the production of fermentable sugars and high viscosity cellulose from lignocellulosic material in a batch or continuous process is provided. Lignocellulosic material is fractionated in a fashion that cellulose is removed as pulp, cooking chemicals can be reused, lignin is separated for the production of process energy, and hemicelluloses are converted into fermentable sugars, while fermentation inhibitors are removed. High yield production of alcohols or organic acids can be obtained from this method using the final reaction step.

A method of hydrothermal hydrocatalytic treating biomass is provided. Lignocellulosic biomass solids is provided to a hydrothermal digestion unit in the presence of a digestive solvent, at least one of ammonia or a source of ammonia, and a supported hydrogenolysis catalyst containing (a) sulfur, (b) Mo or W, and (c) Co, Ni or mixture thereof, incorporated into a suitable support. The lignocellulosic biomass solids and digestive solvent are heated in the presence of hydrogen, supported hydrogenolysis catalyst and the at least one of ammonia or a source of ammonia forming a product solution containing plurality of oxygenated hydrocarbons and ammonia. At least a portion of ammonia is separated and recycled to the hydrothermal digestion unit.

A method to prepare, pulp, and bleach cannabis bast and hurd fibers to allow for the fiber to be incorporated into absorbent cellulosic structures on a wet-laid paper machine while keeping the pectin within the fibers. The wet laid paper machine can use the ATMOS, NTT, ETAD, TAD, or UCTAD method to produce the absorbent cellulosic structure. Absorbent cellulosic structures are produced with the cannabis bast and hurd fibers or with the bast fibers alone with the hurd fibers being combined with paper mill sludge or dust to form a fuel pellet.

The invention relates to a cellulose extracting technology, and specifically relates to a technology that utilizes organic acids to extract cellulose from biomass raw materials in the presence of a hydrogen peroxide catalyst. The technology comprises the following steps: in the presence of a hydrogen peroxide catalyst, utilizing an organic acid to cook biomass raw materials, wherein the organic acid is composed of formic acid with a concentration of 70 to 95 wt% and acetic acid with a concentration of 70 to 95 wt%; extracting and screening so as to obtain screened cellulose pulp; and further bleaching the screened pulp so as to obtain the target cellulose; wherein the cellulose is dissolving pulp or industrial cellulose. The alpha-cellulose content of the cellulose obtained by the method provided by the invention is more than 90 wt%. The technology has the advantages of simple route and low energy consumption.

The present invention discloses methods of bleaching chemical pulp that combine xylanase enzymes with hydrogen peroxide, peracids, or a mixture. The method comprises the steps of carrying out a chemical pulping operation, optionally followed by delignifying the pulp with oxygen, then combining xylanase enzymes with hydrogen peroxide, peracids, or a mixture to bleach the pulp. The method allows the mill to use both xylanase and peracids in a single bleaching tower to decrease the usage of chlorine dioxide and other bleaching chemicals. The pulp bleaching method of the present invention may be performed in a pulp mill as part of a complex pulp bleaching process.

A scalable, energy efficient process for preparing cellulose nanofibers is disclosed. The process employs a depolymerizing treatment with one or both of: (a) a relatively high charge of ozone under conditions that promote the formation of free radicals to chemically depolymerize the cellulose fiber cell wall and interfiber bonds; or (b) a cellulase enzyme. Depolymerization may be estimated by pulp viscosity changes. The depolymerizing treatment is followed by or concurrent with mechanical comminution of the treated fibers, the comminution being done in any of several mechanical comminuting devices, the amount of energy savings varying depending on the type of comminuting system and the treatment conditions. Comminution may be carried out to any of several endpoint measures such as fiber length, % fines or slurry viscosity.

Transition metal complex compounds of polydentate ligands with improved delignifying and bleaching performance. These polydentate ligands are organic ligands which, in aqueous solution and in the presence of atmospheric oxygen, or hydrogen peroxide, form a complex with a transition metal, in particular cobalt. The complexes are mono- or polynuclear and they have, when peroxo compounds are used, better delignifying and bleaching performances than conventional transition metal complex compounds. A delignifying and bleaching method, in which these transition metal complex compounds with polydentate ligands having improved delignifying and bleaching performance are used as catalysts, is also described.

The invention provides for methods for producing pulp (comprising cellulose) and lignin from lignocellulosic material, such as wood chips. The methods involve acid catalyzed hydrolysis. Lignocellulosic material having a relatively high moisture concentration can be used as the starting material. The lignocellulosic material is impregnated with an acid (preferably nitric acid) and heated. During the heating lignin is depolymerized at relatively low temperatures, and the acid catalyst is distilled off. The acid catalyst can be collected and recycled after impregnation and heating. The lignocellulosic material is then digested in an alkaline solution under heat, dissolving the lignin and allowing the pulp to be removed. Acid is added to the black liquor to precipitate the lignin which is then removed. The resultant amber liquor can be further processed into other ancillary products such as alcohols and/or unicellular proteins.

The present invention provides a method for oxidizing a substance (e.g., in a waste stream, drinking water, a paper pulp slurry, or on a surface), which uses free radicals and reactive species generated from multiple oxidants. The method comprises combining peroxynitrite or peroxynitrous acid and at least one additional oxidizing agent for a period of time sufficient to oxidize the substance of interest. The peroxynitrite or peroxynitrous acid preferably is formed by irradiation of nitrate ion and/or nitric acid (e.g., with UV or gamma rays). The yield of free radicals and reactive species, which are the intermediate species that perform the oxidation may be increased by addition of a catalysts, electromagnetic radiation, sonic waves, and/or electrolysis.

Am image presentation system employing microstructured icon elements to form an image. In one form a synthetic optical image system is provided that includes an array of focusing elements, and an image system that includes or is formed from an array or pattern of microstructured icon elements, such as those described below, wherein the microstructured icon elements are designed to collectively form an image or certain desired information, and wherein the array of focusing elements and the image system cooperate, for example through optical coupling, to form a synthetic optical image which image may optionally be magnified. In another form an image presentation system is provided that includes or is formed from an array or pattern of microstructured icon elements, such as those described below, wherein the microstructured icon elements are designed to collectively form an image or certain selected information, and wherein the image system is designed to stand alone and be the image viewed or the information read by use of a magnifying device, such as a magnifying glass or microscope, that is provided separately from the image system.

The present invention relates to a process for preparing a high-yield pulp comprising a) treating a lignocellulose containing material chemically by means of an oxidising system comprising at least one non-enzymatic oxidant substantially free from ozone and chlorine dioxide and an activator at a pH from about 2 to about 6.5; and b) treating the lignocellulose containing material mechanically for a time sufficient to produce a high-yield pulp, wherein the lignocellulose containing material is chemically treated prior to and/or during any mechanical treatment stage, and wherein the lignocellulose containing material is not chemically treated at a pH from about 11.5 to about 14 between stages a) and b).

Oxidative compositions and processes that preserve and enhance the brightness and improve color of pulp or paper when applied during different stages of the papermaking process are identified. The oxidative composition and method maintains and/or enhances brightness, prevents yellowing, and enhances the performance of paper products. Used in combination with optical brighteners and/or chelants the oxidative agents produce a synergistic effect not previously identified in the paper process.