789results about "Washing/displacing pulp-treating liquors" patented technology

The invention relates to a process of detoxifying pretreated lignocellulose-containing material comprising washing the pretreated lignocellulose-containing material in a washing solution and treating the used washing solution to remove an enzyme inhibitor and/or an inhibitor of a fermenting organism before recycling the used washing solution.

A method for separating out waste paper and waste plastic form their mixture including preliminary selecting, using magnetic separator to select out magnetic impurities, using hand to pick up large impurity block without plastic, using fan to blow impurities with different gravities into different grooves at different distance, using mechanical rubbing machine to separate paper fiber from plastic, using single stage floating tank to beat floating matters for releasing paper fiber off, storing floated out plastic and palletizing them for reutilization.

The present invention relates to a method of producing a cellulose-fiber flat structure, the method including obtaining a cellulose-fiber flat structure by filtering a fine cellulose-fiber dispersion containing fine cellulose fibers having an average fiber diameter of 4 to 100 nm, using a filter material having a water permeability of not more than 100 ml/m²·s and an initial tensile modulus of 20 MPa or greater. The present invention is able to produce a cellulose-fiber flat structure by efficiently recovering fine cellulose fibers from a dispersion containing fine cellulose fibers having an average fiber diameter at the nano level. The method of producing a cellulose-fiber flat structure can also be applied to a continuous process.

The present invention relates to a process for the production of xylose and dissolving pulp from xylan-containing biomass, such as hardwood. The invention is based on prehydrolysis of the xylan-containing biomass with SO₂ in specified conditions, followed by chromatographic fractionation, nanofiltration or precipitation crystallization of the xylose-containing prehydrolyzate to obtain a xylose product having a xylose content of at least 55% on DS. The dissolving pulp obtained from the process can be used for example for the production of viscose.

A process for separating organic components from a pulp mill waste stream comprising the steps of washing a cellulose pulp to obtain an aqueous extraction liquor containing organic components, and separating at least a portion of said organic components from the extraction liquor by passing the extraction liquor through at least one nanofiltration membrane. The process may be used in conjunction with a variety of pulp mill processes, including kraft cooking processes, hot caustic extraction processes, sulfite cooking processes, and bleaching processes.

The present invention serves for loading a pulp suspension (S) with calcium carbonate. Liquid calcium hydroxide as milk of lime (7) is added during or before the pulp operation (1) carried out to form the pulp. By introducing gaseous carbon dioxide (8) into the pulp suspension thus treated, a chemical reaction is triggered therein, in which the finely divided calcium carbonate is precipitated. The present invention is particularly economic and effective due to the early addition of calcium oxide or calcium hydroxide.

The invention provides a washing process in the grass pulping. It contains the following steps: A) send the cooked pulp into the presser for pressing to get the coarse pulp. B) Process the coarse pulp through the jumping screen. C) Send the screened pulp into the pulp washer for washing. The rigidity of the screened pulp is potassium permanganate value 16-28 (equals to karber value 24-50). The washed solvent remains 90-150ppm. Take the high rigidity pulp in this invention as materials to prepare bleaching chemical pulp by pressing and washing. The whiteness of the chemical pulp is 68-82%ISO and the removal rate of the lignin is 84-98%. The quality of the bleaching chemical pulp prepared by the grass is similar, even better than that of the exciting hardwood pulp.

The invention provides an efficient and quick cellulose nanocrystalline preparing method.According to the method, a cellulose raw material is pretreated with aqueous alkali and then subjected to acidolysis, and inorganic salt containing metal ions is added during acidolysis to serve as a promoter to promote acidolysis reaction.Reaction condition is mild and easy to control, raw materials needed by reaction are simple and easy to obtain, and the method can be widely applied to preparation of cellulose nanocrystalline from various cellulose raw materials.

The invention discloses an efficient and clean puling and bleaching method dissolving alpha-pulp by Chinese alpine rush. The method comprises the steps of stock preparation, prehydrolysis, alkaline cooking, black liquor extraction, closed screening, total chlorine free bleaching, bleached pulp treatment and the like, namely, adding stock blank after prehydrolysis into a continuous digester to carry out alkaline cooking; adopting a vacuum pulp washer to extract black liquor from sizing agent, sealing and screening, then washing and concentrating the sizing agent through a vacuum filter, wherein the mass concentration of pulp after concentration is larger than or equal to 10%; adding NaOH solution and magnesium salt protective agent in concentrated pulp, then sequentially passing through a medium concentration pump and a medium concentration mixer to enter an upflow type bleaching tower to carry out total chlorine free bleaching. In the invention, the productive process is continuous, and non chlorine bleaching agent is utilized in the production, waste water can flow reversely for reuse and does not contain toxic and harmful adsorbable organic chloride AOX, thereby realizing energy saving and emission reduction, cleaning and bleaching of alpha-pulp production, improving the additional value of Chinese alpine rush, thus the method can be promoted and utilized industrially.

The invention provides a denaturizing production technique of paper making needle wood pulp plate, which solves the problems of uneven dipping, slow hemicelluloses stripping, difficult accumulation descending, uneven cooking, single cooking method, single bleaching method and violent conditions existing in denaturizing production technique of wood pulp in the prior art. The invention comprises the following steps: wood pulp plate paging, alkali soaking, pressing, untwining and dispersion, cooking, washing, impurity removal, bleaching, a secondary washing and pulping; wherein, the wood pulp plate paging, alkali soaking, pressing, untwining and dispersion are to send papers into a alkali dipping barrel with concentration of 6 percent to 18 percent after the paper making bleaching wood pulp plates are separated by a paging device. When the wood pulp plates are changed into pulp with concentration of 3 percent to 6 percent, the pulp with concentration of 3 percent to 6 percent is sent to a squeezer to be squeezed and to untwine and disperse fiber. By adopting the invention, the quality of the dissolved viscose fiber wood pulp can be better and more stable; furthermore, the invention provides wider selection range of raw material.

The invention discloses a production method of natural-color bamboo pulp and natural-color household paper, comprising the following steps: material selection, material preparation, material washing, cooking, screening, washing, oxidation treatment, pulp washing, pulp making and papermaking. According to the above method, after the cooking section is finished, the whiteness of the obtained pulp is 25-28%, the L value is 70-74, the a value is 4-5, and the b value is 19-23. 32%, L value 71-76, a value 3-4, b value 20-25, finally the whiteness of natural color tissue paper is 30-36%, L value 72-78, a value 3-4, b value 20 -25. The present invention adopts all the natural growth raw materials of bamboo with high cellulose content, such as Ci bamboo, Mian bamboo, Siji bamboo, etc., and utilizes advanced displacement cooking technology and oxidation treatment technology to obtain natural-color bamboo pulp with the characteristics of good brightness and natural soft yellow hue. The natural-color household paper produced has fine touch, soft and natural color, and a light bamboo smell. This method also has the characteristics of low energy consumption, high output, high yield, low cost, and low pollution.

The invention discloses paper pulp made from bamboo fiber, a preparation method of the paper pulp, and a paper product made from the paper pulp and belongs to the field of pulp making and papermaking technology. The whiteness of the paper pulp made from bamboo fiber ranges from 20% to 40% ISO, the tensile index is larger than or equal to 7.9 N*m/g, the folding strength ranges from 15 times to 200 times, the fracture length ranges from 5 km to 10 km, the ash content is smaller than or equal to 1%, the tearing strength ranges from 200 mN to 650 mN, and the beating degree ranges from 10 degree SR to 25 degree SR. The preparation method of the paper pulp made from bamboo fiber includes the steps of raw material breaking, stewing, defibering, defibrination, screening and washing. The paper pulp made from bamboo fiber can be used for making culture paper or paper for daily use. The paper pulp has a good performance parameter, can replace conventional wood pulp and is superior to the conventional wood pulp; the preparation method of the paper pulp has the advantages of being high in yield, easy to operate, convenient to produce, low in cost and environmentally friendly, and the 100% natural features of bamboo fiber are kept.

Aiming at the current situation of the cotton dissolving pulp and the wood dissolving pulp and the characteristics of the bamboo and the defects in the existing preparation of the dissolving pulp, the invention provides a method for preparing a chemical bamboo dissolving pulp. The chemical dissolving pulp produced can be widely applied in the cellulose derivative industries such as spinning viscose fiber, nitrocellulose and acetate fiber. The method comprises the following steps of: material preparation, cooking, screening, scrubbing, bleaching and paper making. The cooking procedure comprises two grades of cooking steps, wherein the primary cooking procedure is continuous cooking and the secondary cooking procedure is continuous cooking or intermittent cooking; and the bleaching procedure is elemental chlorine free bleaching or totally chlorine free bleaching. The invention solves the problems existed in the cooking and bleaching procedures. The chemical bamboo dissolving pulp can be prepared with high efficiency, low energy consumption, low material consumption and low pollution.

Provided is an unbleached paper product made from grass type pulp, the unbleached paper product has a brightness of 35-60% ISO, the grass type pulp is unbleached. The unbleached paper product includes an unbleached toilet paper, an unbleached hand towel, an unbleached wiping paper, an unbleached duplicating paper, an unbleached meal container, an unbleached food wrapping paper and an unbleached printing paper. The paper products have a high intensity and have no detection of dioxin and absorbable organic halides in the harmful substance detection test.

Aiming at current situations of cotton and wood dissolving pulp, characters of bamboo material and many disadvantages existing in the existing whiten method for preparing dissolving pulp, the invention provides a whiten method for preparing bamboo material chemical dissolving pulp. The chemical dissolving pulp produced by the invention can be widely applied to derivant industry of celluloses, such as spinning viscose fiber, cellulose nitrate, acetate fiber, etc. The whiten method in the invention uses element-free chlorine bleaching or total chlorine free bleaching, thereby solving the problems existing in the whiten method of bamboo material chemical dissolving pulp and preparing bamboo material chemical dissolving pulp high-efficiently with low energy consumption, low material consumption and low pollution.

The invention discloses a method for preparing bleached pulp by using eucalyptus wood chips, and belongs to the fields of pulping and papermaking. The method comprises the following steps: orderly washing, dewatering and presteaming a eucalyptus wood material, carrying out double helix extrusion, chemical impregnation and high-consistency refining, eliminating, washing and the like. A double helix extruder with a variable pitch and a variable diameter is adopted in extrusion and concentration treatment of the material before defibrination; the damage of the traditional extrusion tearing machine to a fiber is avoided; the quality of the prepared pulp is similar to that of the pulp prepared by qualified chips; the bulk of the pulp can achieve over 3.4 cm<3>/g; the whiteness can achieve over 76% ISO (international standardization organization); effective utilization of the eucalyptus wood chips in the fields of pulping and papermaking is achieved; alkaline hydrogen peroxide which is friendly to the environment is adopted in the craft process; a fewer of pollutants are generated in the pulping process and are non-toxic; instant bleaching and subsequent bleaching reaction are achieved by effectively utilizing the heat energy generated in the pulping process; and steam consumption is reduced.