101results about "Pulping with halogen compounds" patented technology

A process comprising treating a lignocellulosic material preferably pulp in the presence of a transition metal catalyst with a oxidizing agent selected from a group consisting of hydrogen peroxide, hypochlorite, hypochlorous acid and any combination thereof to form a treated lignocellulosic material having a viscosity equal to or less than about 17 cp and having reducing functional groups selected from the group consisting of aldehyde and aldehyde type functional groups at the C6 and C1 positions but predominating at the C1 position.

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.

A method for alteration of the morphology of cellulose fibers, particularly softwood fibers, by (a) subjecting the fibers to a metal ion-activated peroxide treatment carried out at a pH of between about 1 and about 9, preferably between 3 and 7, and (b) subjecting the treated fibers to a refining treatment thereby converts SW fibers to HW-like fibers in many respects. The metal ion-activated peroxide treatment has been noted to act on pulp cellulose and hemi-cellulose, causing oxidation and oxidative degradation of cellulose fibers. The chemical treatment of the pulp, taken alone, is not sufficient to attain the desired modification of the morphology of the fibers, however, subsequent refining or like mechanical treatment of the chemically-treated fibers to achieve a given degree of refinement of the fibers requires dramatically less refining energy to achieve a desired end point of refinement and to impart other desirable properties to the pulp. A pulp of modified SW fibers and a mixture of HW fibers and modified HW fibers are disclosed.

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.

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.

A high pH and a low pH process for reducing the degree of polymerization of a pulp having a hemicellulose content of at least 7%. The high pH is greater than 8, and the low pH process is 2 to 8. The high pH process reduces the degree of polymerization without substantially increasing the copper number. The low pH process requires a subsequent treatment with alkali to reduce the copper number of the pulp to less than 2. The process can be practiced in pulp mills with a bleaching sequence having one or more E or D stages. At the end of the bleach sequence, a pulp having a degree of polymerization of 200 to 1100, a copper number of less than 2, and a hemicellulose content of at least 7% is provided. The pulp can be used to make lyocell fibers.

A multi-function process is described for the separation of cellulose fibers from the other constituents of lignocellulosic biomass such as found in trees, grasses, agricultural waste, and waste paper with application in the preparation of feedstocks for use in the manufacture of paper, plastics, ethanol, and other chemicals. This process minimizes waste disposal problems since it uses only steam, water, and oxygen at elevated temperature in the range of 180° C. to 240° C. for 1 to 10 minutes plus a small amount of chemical reagents to maintain pH in the range 8 to 13. An energy recuperation function is important to the economic viability of the process.

Provided is a nanofiber sheet that sufficiently refined by fibrillation and has high crystallinity of cellulose fiber and can realize a fiber-reinforced composite material exhibiting high transparency, a high elastic modulus, a low coefficient of linear thermal expansion, and high heat resistance and being high in flatness and smoothness. This nanofiber sheet includes crystalline cellulose as the main component and a lignin in an amount of from 10 ppm to 10 wt %. When a fiber / resin composite material obtained by impregnating the nanofiber sheet with tricyclodecane dimethacrylate, subjecting the impregnated product to UV-curing at 20 J / cm2, and heating the cured product in vacuum at 160° C. for two hours includes 60 wt % of the cured tricyclodecane dimethacrylate and 40 wt % of nanofiber, the following physical characteristics (i) to (iii) are satisfied: (i) the parallel light transmittance of light of a wavelength of 600 nm at a sheet thickness of 100 μm is 70% or more; (ii) the Young's modulus is 5.0 GPa or more; and (iii) the coefficient of linear thermal expansion is 20 ppm / K or less.

The present invention discloses methods of bleaching chemical pulp that use xylanase enzymes after chemical bleaching. The method comprises the steps of carrying out a chlorine dioxide stage to produce a partially bleached pulp, treating the partially bleached pulp with a xylanase enzyme, optionally in the presence of oxygen and hydrogen peroxide, in a mild extraction stage, then bleaching the pulp with a second chlorine dioxide stage. The method allows the mill to decrease the usage of sodium hydroxide or other alkali, while decreasing the use of chlorine dioxide, and possibly improving the yield and strength of the pulp, while maintaining a similar level of bleached brightness of the pulp. The pulp bleaching method of the present invention may be performed in a pulp mill as part of a complex pulp bleaching process.

This invention provides a process for treating chemical woodpulp, or chemical cellulose including cotton linter, including the step of applying an electron processing technology (EPT) step to chemical woodpulp, or chemical cellulose, as the case may be, on an in-line basis to provide control of pulp viscosity or degree of polymerisation (DP). The invention also provides a method of process control in treating the aforementioned woodpulp or cellulose, including the step of using radiation dose-viscosity relationship curve for applying an EPT step on an in-line basis. The in-line EPT step may, in one form of the invention, replace and hence eliminate a chemical DP reduction step.

Provided is a method which is capable of producing a cellulose nanofiber dispersion liquid that has a low viscosity and excellent fluidity even at a high concentration, while exhibiting excellent transparency. In a method for producing cellulose nanofibers, wherein a cellulosic starting material is oxidized in water using an oxidant in the presence of an N-oxyl compound and a compound that is selected from the group consisting of a bromide, an iodide and a mixture thereof and the thus obtained oxidized cellulose is defibrated and dispersed, pulp which is obtained by carrying out kraft cooking after a hydrolysis process is used as the cellulosic starting material.

Methods for reducing, and in some cases eliminating, fluorescence in pulp and paper, as well as the resulting articles, are provided. The methods destroy fluorescent activity of agents (e.g., whitening agents) which may be present in the pulp during processing. The methods are particularly applicable to recycling processes that use paper that includes fluorescent whitening agents. The methods may be used to produce recycled pulp and paper that, for example, may be suitably used in food grade applications which require no, or minimal, amount of fluorescence. In some cases, the methods also advantageously enable production of recycled pulp and paper that has reduced amounts of phosphorescence.

There is provided a method of inhibiting the development of a biofilm adjacent a surface, the method comprising intermittently applying a biofilm inhibiting substance to a collection of microorganisms having biofilm developing potential. Other embodiments are also described.

Methods to preserve starch present in pulp are provided and also methods to control calcium precipitation and / or scaling in digesters or BOD systems. The methods can be performed as part of a papermaking process. Process water containing pulp can be treated with a chloramine. Process water containing pulp with native starch can receive a double treatment with at least one biocide, such as chloramine, and at least one oxidant, such as sodium hypochlorite. The treatment can be performed in any suitable manner. The treatment can be performed at one or more stages or locations in a papermaking system. A target residual chloramine value or range can be achieved by the treatment. Packaging sheets / boards and other paper products manufactured using the methods provided exhibit superior strength and other desirable characteristics.

Described herein are processes for the production of a cellulose pulp and processes for isolating cellulose from cellulose-containing biomass. The processes of the invention comprises contacting the biomass with a source of anions and a source of cations, the source of anions and the source of cations being selected to react exothermically with the biomass and with each other. The processes of the invention have the particularity of generating exothermic reactions through enthalpies of reaction and mixture. Accordingly, the processes of the invention do not require any supply of external energy since the required energy is provided by chemical reagents that are already present in the biomass or added as needed. The invention also relates to isolated cellulose obtained from these processes and the use of same in various materials.

A method for producing nanocellulose is described herein. The method includes contacting a cellulosic material with an oxidizing agent, and a compound selected from the group consisting of an alkali metal bromide, an alkali metal iodide, an alkali metal fluoride, an alkali metal chloride, or a combination thereof, in an aqueous solution to provide an oxidized cellulose mixture. The nanocellulose prepared according to the method is also described.

The invention discloses a method for manufacturing nanofiber transparent paper from straw, belonging to the field of papermaking. According to the invention, with adoption of oxidized fiber of a 1,3-dihydroxyacetone oxidization system, the electrostatic repulsive force among nano-cellulose is enhanced, so that the cellulose can be separated from cell walls completely, and the transparent paper has higher transparency and excellent mechanical strength. Sodium hypochlorite can be used as an oxidizing agent, has a bleaching function due to strong oxidizing property, and can react with little lignin left in original fiber to remove the lignin so as to improve light transmission. The raw materials are readily available, and the transparent paper is biologically degradable and cheap.

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.

The invention relates to a method of bleaching cellulose pulp in a bleach line having at least two bleaching steps D1, D2 of alkaline or acidic type, and a bleaching line for the method, in which the filtrate distribution is led up through the bleaching line in counter-current to the flow of cellulose pulp established in the bleaching line. Instead of a conventional filtrate distribution including filtrate tanks, a single joint main conduit 1 is used for the bleaching steps of the same type. Wash filtrate obtained from the wash steps of the same type used after or before the bleaching step, is led to a branch point A2, A4, A6 on the main conduit 1, that is positioned after the branch point for drawing off of wash and / or dilution liquor for the wash step in question A1, A3, A5, A7. All branch points in the joint main conduit are in open communication with each other in the main conduit, at least as seen in a direction from the last bleaching step. Hereby, a simplified and improved filtrate distribution system with an improved runnability is obtained.

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.

A method of bleaching chemical pulp with xylanase after chemical bleaching is provided. The method comprises the steps of exposing chemical pulp to a chlorine dioxide bleaching stage to produce a partially bleached pulp, treating the partially bleached pulp with a xylanase in an enzyme treatment stage at a pH of about 3 to about 8, then carrying out an alkaline extraction of the pulp. The pulp bleaching method of the present invention may be performed in a pulp mill as part of a complex pulp bleaching process.

In a method for catalytic oxidation of cellulose a heterocyclic nitroxyl radical is used as catalyst, hypochlorite is used as main oxidant acting as oxygen source, and a tertiary amine or chlorine dioxide as an activator of the heterocyclic nitroxyl radical.

The invention discloses a method for utilizing straw and waste paper pulp to prepare high strength corrugated base paper, and relates to the field of utilizing cellulose to make paper. After the strawis dried, straw husk is removed to separate out straw medulla, the straw medulla is pulverized, the straw medulla powder is mixed with a NaOH and / or KOH solution of which the mass concentration is 1-10% till the mass concentration of the material is 0.5-5%, after being soaked, the material is washed to be neutral, and water is added to obtain straw medulla pulp, wherein the concentration of the straw medulla is 0.5-5%; then peroxyacetic acid is added into the straw medulla pulp till the mass concentration of peroxyacetic acid is 1-8%, or a hydrochloric acid solution is added into the straw medulla pulp to adjust the pH value of the straw medulla pulp to be 2 or below, then chlorine dioxide is added till the mass concentration of chlorine dioxide in the straw medulla pulp is 1-8%; then thestraw medulla pulp is stirred or oscillated, after being washed to be neutral, the straw medulla pulp is mixed with the waste paper pulp, the mass percentage of the straw medulla in mixed paper pulpis 10-30%, and the mixed paper pulp is utilized to make the corrugated base paper.

Process for bleaching of pulps following cooking of the lignocellulosic material with soda and anthraquinone. The process may produce a whiteness on par with the bleaching of kraft pulp when using a similar bleaching sequence. In some instances, the bleaching sequence may be O-A-Do-Eop-D, O-A-ZDo-Eop-D, A-Do, or A-ZDO.