The present invention relates to a process for producing cellulose with low inorganic impurities from sugarcane bagasse, the process comprising treating prehydrolysed sugarcane bagasse with a mixture of sulfite and at least one alkali to obtain residue having undissolved cellulose along with lignin rich liquor. The residue having undissolved cellulose is further subjected to delignification and addition of at least one enzyme to obtain a cellulose rich pulp. The cellulose rich pulp obtained is then treated with bleaching agents followed by separating pure cellulose rich pulp having high a-cellulose content and low inorganic impurities.

The present application relates to a method for preparing dissolving pulp by TCF bleaching of poplar KP, including: preparing poplar KP by pre-hydrolysis kraft process with poplar as a raw material, and OZQP bleaching of the poplar KP to obtain dissolving pulp, wherein O denotes oxygen delignification, Z denotes ozone bleaching, Q denotes chelating treatment, and P denotes hydrogen peroxide bleaching. The dissolving pulp prepared by the same exhibits that all indexes can meet the requirements of excellent products in dissolving pulp industry standard (QB/T4898-2015), and most of the indexes are far superior to those of excellent products, and thus it can completely replace imported dissolving pulp.

The present invention relates to treatment of dissolving pulp with a lytic polysaccharide monooxygenase. The lytic polysaccharide monooxygenase treatment results in reduced viscosity and/or improved viscosity control in the dissolving pulp production process and/or 5 increased reactivity of the dissolving pulp.

Unique, inexpensive, and strong biocomposites are obtained from blending cellulose matrix materials pith lignocellulosic reinforcement materials with the aid of alkaline aqueous solvent and cold temperatures. These lignocellulosic composites (LCs) are produced without use of any thermoplastic resins, adhesives, catalysts, plasticizers or d chemical or physical procedures. The LCs include a matrix and a reinforcement material. The matrix is a cellulose material (e.g., cotton, hemp, flax, or wood) that is liquefied using an aqueous alkaline solvent solution under cold temperatures to more readily adhere and or incorporate/encapsulate the lignocellulosic reinforcements (wood chips, fibers, and other lignocellulosic sources).

The present invention relates to a method of production of a paper fibre composition, comprising the steps of: a) Providing a vessel, b) Providing Na.sub.2S0.sub.3 in the range of 12-122 kg/bdt combined with NaOH in the range of 0-97 kg/bdt, or NaHSO.sub.3 in the range of 10-100 kg/bdt combined with NaOH in the range of 10-100 kg/bdt to said vessel, c) Providing wood, preferably softwood chips to said vessel for pre-treatment, d) Providing heat and pressure to said vessel in order be able control the vessel to have a temperature T comprised in the range of 160 C.-184 C., e) Controlling the retention time t for the wood chips, in relation to the temperature T of the content of the vessel, wherein T is controlled to be within the range of step d) and t is controlled to be in the range of 2-27 min, preferably in the range of 2-25 min, more preferred in the range of 5-20 min, f) Providing a defibration device coupled to the outlet of said vessel, the defibriation device being a refiner, mill, defibrator, fiberizer, or the like, g) Providing the pre-treated wood chips to the defibration device, h) Providing an energy consumption of 75-1000 kWh/bdt in said defibration device. The invention also relates to a paper fibre composition prepared by the method and a paper or paperboard or molded pulp made from the paper fibre composition.

A super strong and tough densified wood structure is formed by subjecting a cellulose-based natural wood material to a chemical treatment that partially removes lignin therefrom. The treated wood retains lumina of the natural wood, with cellulose nanofibers of cell walls being aligned. The treated wood is then pressed in a direction crossing the direction in which the lumina extend, such that the lumina collapse and any residual fluid within the wood is removed. As a result, the cell walls become entangled and hydrogen bonds are formed between adjacent cellulose nanofibers, thereby improving the strength and toughness of the wood among other mechanical properties. By further modifying, manipulating, or machining the densified wood, it can be adapted to various applications.

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).

The disclosure relates to the technical field of dissolving pulp preparation, and particularly relates to a method for producing acetate grade dissolving pulp utilizing poplar residual slabs. The method comprises the following steps: adding an auxiliary agent for prehydrolysis, performing a Soda/AQ cooking I segment, performing a Soda/AQ cooking II segment, performing OpD.sub.QE.sub.PP bleaching and performing enzyme coprocessing, thereby preparing high-purity high-reactivity poplar residual slab acetate grade dissolving pulp. In the method, used chemicals are clean and environmental friendly, and production process is clean.

A method for manufacturing dissolving pulp using wood material is disclosed. The method comprises subjecting the wood material to a hydrothermal treatment using steam and/or water, digesting the wood material obtained to a pulp in a kraft cooking process; subjecting the pulp to a cold caustic extraction CCE; and dewatering, washing and pressing the pulp to get a pulp product having a carbohydrate content.

The wood material can be a coniferous wood material, and whereby the mild hydrothermal treatment is performed to reach a P-factor of from 100-300, and whereby the cold caustic extraction is executed to reach a combined concentration of anhydromannose and anhydroxylose of 5 weight %, or less, of the carbohydrate content of the pulp product.

The invention relates to novel methods for processing lignocellulosic material. More specifically, the invention proves an integrated approach for processing cellulose to obtain paper and pulp and valorizing lignin to obtain value-added chemicals and products.