A process for producing refined cotton with a high polymerization degree includes: a. selection of material; b. impurity removal; c. impregnation; d. pretreatment: compounding triethanolamine, sodium carbonate, copper sulfate and magnesium oxide in equal proportion to form a cooking compound adjuvant with a mass concentration of 0.2-0.5%, putting the cookingcompound adjuvant into a spherical digester together with the cotton linter subjected to the impregnation treatment, heating to 70 C, stopping heating, and subjecting to idling pretreatment for 40-60 min; e. cooking; f. cooling of the spherical digester; g. formulating a chlorine dioxide bleaching stabilization solution; h. a first stage of bleaching; I. alkali treatment; J. a second stage of bleaching; K. dechlorination; and 1. rolling and drying by baking.

The invention relates to a method for obtaining cellulose fibres from fibrous biomass, in which: the biomass is first subjected to thermo-pressure hydrolysis, preferably with steam explosion, in a thermo-pressure hydrolysis plant, and then separation of the fibrous sludge obtained from the thermo-pressure hydrolysis plant is carried out in at least one separation plant, wherein a press cake of cellulose fibres, preferably with a dry material content of over 20%, preferably of over 25%, and a filtrate of flowable, solids-rich thin sludge are obtained, and wherein the thin sludge is fed to a biogas plant as a fermentation substrate to obtain biogas. The invention also relates to a plant for carrying out this method.

A process to delignify biomass, said process comprising the steps of: providing a vessel; providing biomass comprising lignin, hemicellulose and cellulose fibers into said vessel; providing a aqueous acidic composition comprising a sulfuric acid component; providing a peroxide component; exposing said biomass to said sulfuric acid component and peroxide component, creating a reaction mass; allowing said sulfuric acid component and peroxide component to come into contact with said biomass for a period of time sufficient to a delignification reaction to occur and remove over 90 wt % of said lignin and hemicellulose from said biomass; and controlling the temperature of the delignification reaction to maintain it below 55° C.

According to an example aspect of the present invention, there is provided a process for the conversion of cellulosic waste material into a recycled cellulose product comprising the steps of cooking the waste material in a cooking liquor to remove lignin from the waste material and provide a delignified pulp, dissolving the delignified pulp in an ionic liquid to provide a spinning dope suitable for dry jet-wet spinning in an ionic liquid solution, and subjecting the spinning dope to a further processing step to provide a recycled cellulose product, said further step selected from the group of spinning cellulose fibers for use in textiles from the solution, extruding a film product for use in packaging, regenerating the dope as a hydrogel and regenerating the dope as an aerogel.

A method of producing chemical pulp including at least the following steps: a) wood chips or other comminuted ligno-cellulosic fibrous material is treated with a polysulfide-containing cooking liquor in an impregnation stage at a temperature of 90-145° C., and b) slurry of fibrous material from step a) is heated into cooking temperature and cooked for producing pulp having a desired kappa number. After step a) mercaptide ions are added into the slurry of fibrous material and the fibrous material is treated at cooking temperature in step b).

A piece of natural plant material is subjected to one or more chemical treatments to remove substantially all lignin therefrom, thereby allowing the extraction of delignified, cellulose-based fibers. For example, the natural plant material can be a grass, such as bamboo or gladiolus. Subsequent drying of the extracted fiber densifies the structure, yielding improved mechanical properties. In some embodiments, the extracted fibers can be used, either alone or in combination with other materials, as a structural material. For example, the extracted fibers can be embedded within, infiltrated with, coated by, or otherwise combined with a polymer or concrete to form a composite material.

A low energy production process for producing paper pulp from lignocellulosic biomass, the process comprising the following successive steps: a) extracting lignins and hemicellulose from lignocellulosic biomass by putting at least one solid lignocellulosic raw material in the presence of a mixture, composed only of water and of formic acid, at atmospheric pressure and under controlled conditions of reaction temperature between ambient temperature and the reflux temperature of the mixture at atmospheric pressure, preferably between 80° C. and 100° C., with a weight ratio of the at least one solid lignocellulosic raw material/liquid mixture comprised between 1/1 and 1/15, and for a determined period of time of reaction; and b) separating, at atmospheric pressure and at the reaction temperature, a solid fraction, constituting raw paper pulp, from an organic phase containing in solution at least the starting formic acid and water mixture, solubilized monomeric and polymeric sugars, lignins.

A system comprising a pulper configured to (i) accept surfactant, a liquid and fiber stock and (ii) generate a foam that suspends the fiber stock, wherein the foam has a half-life; a headbox configured to receive the foam-suspended fiber stock from the pulper and displace the foam-suspended fiber stock onto a forming wire, wherein a time it takes the foam-suspended fiber stock to move from the pulper to the headbox is less than the half-life; and a foam return device that removes at least some of the foam from the forming wire and returns the at least some of the foam to the pulper.

An evaporative device has a piece of at least partially-delignified plant material. The at least partially-delignified plant material has a modified microstructure including a plurality of vessels, a plurality of fibers, and a plurality of engineered micropores. Each vessel can define a first lumen having a maximum cross-sectional dimension of at least 100 μm. Each fiber can define a second lumen having a maximum cross-sectional dimension less than or equal to 20 μm. The engineered micropores can extend through walls of the vessels or fibers so as to fluidically interconnect the first and second lumina. In some embodiments, the plant material is reed or bamboo.

A method for controlling the deposition of stickies in pulping and papermaking processes comprises adding to fibre pulp or stock an additive comprising an organo-modified siloxane comprising units of the formula: [R.sup.1.sub.aZ.sub.bSiO.sub.(4-a-b)/2].sub.n in which each R.sup.1 is independently selected from a hydrogen atom, an alkyl, aryl, alkenyl, aralkyl, alkaryl, alkoxy, alkanoyloxy, hydroxyl, ester or ether group, and each Z is independently selected from an alkyl group substituted with an amine, amide, carboxyl, ester, or epoxy group, or preferably at least one or more groups —R.sup.2—(OC.sub.pH.sub.2p).sub.q(OC.sub.rH.sub.2r).sub.S—R.sup.3; wherein n is an integer greater than 1; a and b are independently 0, 1, 2 or 3; R.sup.2 is an alkylene group or a direct bond; R.sup.3 is a group as defined for R.sup.1 or Z above; p and r are independently an integer from 1 to 6; q and s are independently 0 or an integer such that 1≦q+s≦400; and wherein each molecule of the organo-modified siloxane contains at least one group Z. The organo-modified siloxane is preferably a hydroxyl- or alkyl-endcapped linear polydimethylsiloxane, in which 5 to 18 mole percent of silicon atoms are substituted by Z groups of the formula —R.sup.2—(OC.sub.pH.sub.2p).sub.q(OC.sub.rH.sub.2r).sub.s—R.sup.3, in which p is 2, r is 3 and q and s are independently 10 to 20, R.sup.2 is an alkylene group having from 1 to 6 carbon atoms or a direct bond, and R.sup.3 is a hydrogen atom or a hydroxyl, alkoxy, ester or ether group.