A method for producing levulinic acid from lignocellulosic biomass comprising hemicellulose including one or more six carbon chain compound precursors comprises the steps of hydrolyzing the lignocellulosic biomass to form a first phase comprising partially hydrolyzed lignocellulosic biomass including cellulose and lignin and a second phase comprising one or more five carbon chain sugars and one or more six carbon chain sugars from degradation of the hemicellulose, separating the first phase from the second phase, and converting at least a portion of the one or more six carbon chain sugars to levulinic acid.

A method of forming glass-like sheets using date palm seeds is provided. The method includes milling date palm seeds to form a powder. The powder is compressed to form discs, after which the discs are immersed in a delignification solution followed by removal from the delignification solution and washing. The discs formed from the date palm seed powder are immersed in a bleaching solution until a change in color is observed from opaque to transparent. The transparent discs thus formed are then hardened through application of an epoxy resin. The initial grinding procedure may be substituted by an initial slicing step of the date palm seeds in a similar method of forming the glass-like sheets.

Discloses are a method for preparing fluff pulp from bamboos, and the fluff pulp prepared thereby. The method comprises the following steps: treating the bamboos with high-concentration alkali at a relatively mild temperature, after a certain period of treatment, replacing a treatment liquid for separating hemicellulose with a weak black liquor; Kraft cooking the treated bamboos to obtain unbleached bamboo pulp, removing rejects in the unbleached bamboo pulp by using a slotted screen; then removing miscellaneous cells by using a microporous sieve; carrying out two stages of oxygen delignification on the screened pulp; carrying out ECF bleaching treatment of a D.sub.0EpD.sub.1P process; and finally obtaining the bamboo fluff pulp which has high whiteness, low DCM extract content, low ash content and long fiber length, contains 4.2-4.6 million fibers per gram, and has relatively high bulkiness.

The present application relates to a process to obtain fully oxidized white liquor from white liquor used in a Kraft pulp process. Said fully oxidized white liquor is suitable to be used in alkaline steps of certain stages of the Kraft pulp process fiberline in order to partly or totally substitute the purchased sodium hydroxide used in those stages. The presently disclosed process also allows to purge non-process elements (NPE's) by purging alkaline wash filtrates to a wastewater treatment plant.

Sustainable paper-based packaging materials, e.g., paper-based food packaging materials, are described. The packaging materials are based on paper formed from fiber derived from waste biomass, such as hemp hurds, mixes containing hemp hurds and hemp bast fibers, bagasse, and cocoa pod husks. Also described are methods of making the packaging materials. The methods can include environmentally friendly pulping and/or bleaching processes.

The invention relates to processes for manufacturing pulp and more specifically to improved processes for manufacturing dissolving pulp. The processes have primarily been developed to be used in connection with large scale kraft processes, i.e. they have been designed to be incorporated into a plant. A liquor derivable from the process and comprising xylan, lignin, alkali and water is also disclosed as well as a dissolving pulp produced by the process.

A method used in connection with the recovery of pulping chemicals from spent pulping liquor produced by kraft-type pulping at very high sulphidity. In the method, spent pulping liquor is acidified to a relatively low pH which converts a most or all of the sulphide and hydrosulphide in the liquor to hydrogen sulfide. Sulphur containing gases released from the acidification of the spent pulping liquor, together with other sulphur gases collected at the pulp mill, are converted into an acid compound. This acid compound is employed as an acidification agent in the acidification of the spent pulping liquor. The amount of acid compound generated by the conversion of sulphur containing gases may be sufficient to provide most, if not all, of the acid needed for the acidification of the spent pulping liquor.

The invention relates to a method for reducing pulp viscosity in production of dissolving pulp. The method comprises producing cellulose pulp, whereby the obtained cellulose pulp has a cellulose content of at least 90%, and bleaching the obtained cellulose pulp. The cellulose pulp is treated after bleaching with performic acid.

The invention is related to improved polysulfide production process wherein a specific second filtration process (F.sub.x) is installed before the polysulfide reactor (R.sub.c). According to the inventive method a cross flow filter (F.sub.x) is used as the second filtration process reaching astonishing low levels of residual solids in the white liquor as well as extended availability of the second filtration process. The subsequent polysulfide reactor, either in form of an electrolytic cell or in form of a bed of active carbon, could then also be operated at increased availability. The invention increases the production volume of polysulfide and the retentate from the cross filtering process may be bled out continuously to a process position ahead of a first filtering or clarification stage, capturing most of the increased content of lime mud particles in the retentate and causing less disturbance of the process with a minimum of tanks and pumps.

According to an example aspect of the present invention, there is provided a method comprising: providing wood chips; impregnating the wood chips with an impregnating composition to obtain impregnated wood chips; refining the impregnated wood chips in at least one refiner to obtain a refined pulp composition; screening the refined pulp composition to obtain an accept fraction and a reject fraction; and directing at least part of the reject fraction from the screening step back to said impregnating step or to a step preceding said impregnating step.