WO2009015556A1 - Procédé de production de pâtes à papier à partir d'herbes et pâtes obtenues par le procédé - Google Patents

Procédé de production de pâtes à papier à partir d'herbes et pâtes obtenues par le procédé Download PDF

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Publication number
WO2009015556A1
WO2009015556A1 PCT/CN2008/001378 CN2008001378W WO2009015556A1 WO 2009015556 A1 WO2009015556 A1 WO 2009015556A1 CN 2008001378 W CN2008001378 W CN 2008001378W WO 2009015556 A1 WO2009015556 A1 WO 2009015556A1
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Prior art keywords
pulp
cooking
slurry
amount
temperature
Prior art date
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Ceased
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PCT/CN2008/001378
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English (en)
Chinese (zh)
Inventor
Mingxin Song
Songtao Chen
Hongfa Li
Jihui Yang
Yanjin Bi
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Shandong Tralin Paper Co Ltd
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Shandong Tralin Paper Co Ltd
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Priority claimed from CNB2007101296347A external-priority patent/CN100402742C/zh
Application filed by Shandong Tralin Paper Co Ltd filed Critical Shandong Tralin Paper Co Ltd
Publication of WO2009015556A1 publication Critical patent/WO2009015556A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H11/00—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only
    • D21H11/12—Pulp from non-woody plants or crops, e.g. cotton, flax, straw, bagasse
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C5/00—Other processes for obtaining cellulose, e.g. cooking cotton linters ; Processes characterised by the choice of cellulose-containing starting materials
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C3/00—Pulping cellulose-containing materials
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
    • D21C9/10—Bleaching ; Apparatus therefor

Definitions

  • the invention relates to a preparation method of grass pulp for papermaking and a pulp prepared thereby, and belongs to the field of pulp and papermaking.
  • the plant fiber raw materials for papermaking generally include: wood fibers and grass fibers.
  • Wood fiber divided into softwood and hardwood, the shape of the two fibers is very different.
  • Softwood fiber Because of its large fiber length, soft fiber and low content of fine components, it is easy to produce high-strength slurry, so softwood fiber is an excellent raw material for paper making.
  • Hardwood fiber Due to the short fiber and high content of ducts and parenchyma cells, the paper strength is not as good as that of softwood pulp. Due to poor interweaving of the duct and fiber network, it is easy to produce powder, but the fiber is short on the paper. The stiffness and smoothness are favorable.
  • the miscellaneous cells due to the high content of miscellaneous cells, the miscellaneous cells have many adverse effects on the pulp papermaking, and the interlacing of the fibers is poor, affecting the strength of the pulp.
  • the population of the hetero cells adheres to the paper it is easy to fall off the powder.
  • the miscellaneous cell lignin content is high, it is not easy to bleach, and it is easy to form yellow dust spots on the paper surface, and the pulping and papermaking value is the lowest.
  • the difference in the strength of the paper is usually expressed by the low value of the crack and the tear. The degree of low value and the number of times of folding resistance are small.
  • the grass pulping technology is a systematic project.
  • the whole process of pulping should be studied according to the heterogeneity of the biological structure of the grass fiber raw materials and the specificity of the chemical composition.
  • the existing pulp plants are used to produce pulp.
  • the methods are: chemical method, mechanical method, chemical mechanical method.
  • Chemical pulping is a widely used pulping method in chemical cooking by removing some of the ingredients in the grass plant fiber raw material by chemical action. Lime method, caustic soda method, strontium-soda method, sulphate method, sulfite method, etc.
  • the yield of pulp is more than 50%, the good is 57%, the crack length is more than 4000m, the good is more than 7000m, the depth of turf can be obtained, the bleaching is good, the strength is good, the cooking yield is good. High, it can save energy, reduce pollution, reduce consumption and so on.
  • the high-hardness pulp especially the high-hardness pulp having a potassium permanganate value of 16-28 in the present invention, which corresponds to a Kappa number of 24-50, the pulp having a whiteness of 65-82 ⁇ 3 ⁇ 4ISO in the present invention is produced. , considered to be impossible in the prior art.
  • the bleaching chemical slurry of the present invention is developed based on the high hardness pulp obtained by cooking.
  • the sulfite method in the prior art uses plant fiber as a raw material, and the process is first preparing the raw materials, and the raw materials for the pre-prepared pulp are put into steaming balls, vertical pans and continuous steaming (spherical digester, vertical).
  • a chemical such as ammonium sulfite is added, and steam is heated into a steaming ball, a vertical pot or a continuous steaming, and the mixture is kept for a while to obtain a brown pulp.
  • the cooking is first carried out at a lower temperature, at which time the lignin and the fiber are partially separated, and when the temperature is raised for cooking, the low temperature is reversed.
  • the method for producing chemical wood pulp disclosed in "Production Method of Chemical Wood Pulp” includes impregnation, extrusion disintegration, delignification, and the extrusion disintegration is carried out before cooking, and the structure of the wood chip is made by the process. Loose, the wood chips become thinner, the bulk density becomes smaller, and the wood filaments forming the three-dimensional network structure, because the specific surface area of the wood filaments becomes larger, it is easy to uniformly absorb the medicine, and the reaction rate of the delignification is correspondingly accelerated, and the reactants are also Easy to dissolve, this stage is to enhance the uniform penetration of the cooking liquid, reduce the amount of cooking chemicals, reduce cooking time, and improve the uniformity of cooking.
  • the patent number CN99221397.5 entitled “Wheat Grass Extrusion Disintegration Machine” patent also discloses a disintegration device, which is mainly used for squeezing and dissolving the softened and moist wheat straw, the purpose of which is to overcome the present
  • the raw material preparation method of wheat straw has low impurity rate and serious pollution, which brings many adverse effects to the subsequent pulp and paper production, and also brings great difficulty to the alkali recovery of the cooking black liquor.
  • the wheat straw squeezer is applied in the dry preparation, and has no significant effect on the oxygen delignification process of the cooked pulp.
  • the slurry prepared for grass plants has more heterogeneous cells and a higher content of hemicellulose, which is easy to hydrate, and the drainage performance is inferior to that of wood pulp, which is difficult to wash, and the wood obtained by the alkali method is used.
  • the pulp is more difficult to wash than the wood pulp obtained by the acid method.
  • the viscosity of the slurry is small, resulting in good drainage performance at the beginning, but the final cleaning degree is poor. It is because some of the waste liquid in the cooking is present inside the fiber. For the slurry with high hardness, the fiber is less damaged.
  • the internal waste liquid is mainly diffused from the cell cavity through the paper hole.
  • the pulp with high hardness and the waste liquid in the fiber The diffusion resistance is large and the more difficult it is to wash. It is more difficult to wash the straw pulp obtained by the alkaline method than the wood pulp.
  • the oxygen delignification method is generally used to prepare wood pulp, which is a process that is less polluting to the environment and has a high rate of delignification.
  • wood pulp is a process that is less polluting to the environment and has a high rate of delignification.
  • the degree of enthalpy increase is too high due to the medium concentration transport of grass fibers, which seriously affects the water filtration performance of the straw pulp. Therefore, it is generally less used to prepare grass pulp.
  • CN1737255 discloses a pulp cleaning bleaching process comprising: (1) single stage double column oxygen delignification; (2) hypochlorite bleaching; (3) activator pretreatment; (4) hydrogen peroxide bleaching.
  • the method uses non-polluting oxygen and hydrogen peroxide to clean the bleaching agent, achieves high-efficiency bleaching by single-stage double-tower oxygen bleaching and activation pretreatment, and has high bleaching efficiency and whiteness of more than 85%.
  • the construction investment is only chlorine dioxide. Less than 1/5 of bleaching; less pollution, AOX is reduced by more than 70%, wastewater discharge is reduced by 70%, COD and Cr emissions are reduced by more than 60%; production line can be used for the construction of pulp bleaching production line or in the existing pulp bleaching production line. It is specially transformed and specially suitable for the clean bleaching of chemical pulp of wood and grass plant materials with a daily output of more than 50 tons.
  • the system is only used on reed pulp and has never been used on rice straw pulp. This method requires oxygen de-lignin from a double column, which is costly, and the subsequent steps require the use of an activator and hydrogen peroxide. Agents, etc., lead to an increase in pulp costs and a complicated process.
  • CN1616761 discloses a chlorine bleaching method for alkaline sodium sulfite grass pulp, which adopts pre-bleaching acid H202 pretreatment, two-stage oxygen delignification, chlorine dioxide bleaching, oxygen-enhanced alkali extraction and H202 and insurance powder.
  • the H 2 0 2 /H 2 S0 4 -01-02-D-Eop-PY bleaching process consisting of the final bleaching section was used to complete the chlorine bleaching of the reed pulp.
  • the method requires 3 ⁇ 40 2 pretreatment and two stages of oxygen delignification, and also requires chlorine dioxide bleaching and oxygen enhanced alkali extraction, which is complicated in process and high in cost.
  • the preparation methods can be divided into dry method, wet method, and comprehensive method according to the treatment method.
  • Dry preparation means that the raw materials are subjected to various necessary treatments under certain moisture (ie, storage of moisture) to meet the requirements of the pulp and paper production process and product quality.
  • the method is widely used in China because of simple process, few equipment, convenient operation, low energy consumption and mature technology.
  • the dry preparation has a poor purification effect.
  • the grass material is cut into a certain length (15-30mm) of grass pieces, and then filtered to remove impurities such as roots, leaves, ears, grains, dust and the like.
  • the process of dry preparation of rice straw plant raw materials generally includes the following steps: (1) raw materials for rice straw Transfer to the lawn mower for cutting grass; (2) Send the cut grass flute or conveyor belt to the screening dust removal equipment to remove heavy impurities such as heavier sand and grain; (3) transport to the digester Cooking in the middle.
  • the following steps are often used: (1) Raw materials such as reeds and awnings are sent to the cutting machine through the conveyor belt; (2) The cut raw materials are sent to the cyclone dust collector. (3) The raw materials separated from the cyclone separator are sent to a screening machine for screening; (4) The screened raw materials are sent to a digester for cooking.
  • the packaging tape obtained after the preparation of the material cannot remove the packaging tape and the larger grass joint. Due to the existence of the grass joint, the grass piece obtained by the prior art preparation method is subjected to cooking and pulping. The obtained pulp is prone to yellow spots, and after the cooking in the prior art, it is necessary to remove impurities such as grass joints by screening or other measures, thereby obtaining a yellow spot phenomenon of the slurry.
  • the preparation method only separates light impurities such as gravel, grain and the like, and light impurities such as fine dust, and the energy in the raw material.
  • the impurities such as the grass joints that consume the cooking agent during the cooking process are not well removed, thus causing the consumption of the cooking liquid in the subsequent cooking process.
  • the grass section retains its original shape after being cooked into a slurry, and the yellow spot in the pulp is not easily removed, which affects the quality of the pulp.
  • the raw material cooking liquid sent to the digester does not easily penetrate into the interior of the grass material, which may cause uneven cooking.
  • the primary object of the present invention is to provide a method for preparing a grass pulp which is obtained by cooking to obtain a high hardness pulp as a core, and in combination with the steps of squeezing, washing and dissolving, to obtain a high quality pulp.
  • a method for preparing grass pulp comprising the steps of:
  • the high-hardness pulp obtained in the step (1) is subjected to slurrying and washing to obtain a washed slurry;
  • the step of preparing the grass raw material before the cooking, the step of preparing the grass raw material is further included, and the preparation comprises:
  • the process of cutting and raking the grass raw material is carried out in a hammer crusher, the hammer crusher comprising: a casing, a horizontally disposed main shaft in the casing, and being disposed on the shaft a plurality of hammer disks, one side of the hammer plate is provided with a support shaft perpendicular to the hammer plate, the support shaft is provided with a swingable hammer body, and the hammer body comprises a set connected to the support a sleeve on the shaft and a hammer piece disposed on the sleeve, the casing is provided with a feed port and a discharge port, and the hammer crusher is divided and conveyed along the casing in a horizontal direction a material section, a cutting section and a discharge separation section, wherein the feeding port and the discharging port are respectively disposed on the casing of the conveying feeding section and the discharging separation section; the conveying feeding section and the cutting section
  • the squeezing according to the present invention comprises: introducing the high-hardness pulp having a concentration of 8-15% from the inlet of the extruder, and extruding the black liquor under the action of the pressing force to obtain a concentration of 18-25%.
  • Slurry slurry; the pulper is preferably a reduced diameter single screw extruder, double screw extruder or twin roller extruder.
  • the washing according to the present invention comprises: using the slurry after the squeezing with a concentration of 3-6.2° Be ' at a temperature of 70-8 CTC and a black liquor of pH 8-8.3 or one of the clear water at a temperature of 70-80 ° C or Both are washed, and the washing is carried out in a vacuum washer, a pressure washer or a horizontal belt washer.
  • the disintegration according to the present invention comprises: treating the slurry obtained after washing with a high-frequency disintegrator, a crucible, a disc grinder, a disc grinder in a beating apparatus or a fiber separator to loosen the fiber structure.
  • the process of cutting and raking the grass raw material according to the present invention is carried out in a hammer crusher; the hammer crusher is modified by using an existing hammer mill; the screening process is in a cylinder
  • the inner sieve of the cylindrical sieve is a circular hole with a diameter of 30 mm or a square hole of 30 X 30 mm
  • the outer sieve is a circular hole with a diameter of 4-6 mm.
  • the grass raw materials processed by the crusher can not only achieve the effect of cutting the raw materials, but also can be smashed, torn and cut, so that the straw of the raw material is cleaved, the impurities inside the straw are discharged, and the raw materials are cracked. Shape or strip, more favorable Infiltration of the cooking liquid further enhances the cooking effect.
  • the angle between the hammer piece of the hammer body of the hammer feeder and the support shaft axis of the hammer crusher is 50-70 degrees; the hammer piece of the hammer body of the cut-off section and the axis of the support shaft The angle is 30-50 degrees.
  • Such an angle in the feed section facilitates the mixing of the raw materials into a relatively regular arrangement, and the material gradually aligns substantially parallel to the axis of the spindle during the process to facilitate subsequent crushing.
  • the angle of the cut-off section satisfies the need for breakage while ensuring a certain advancement of the material.
  • the dry preparation is performed by using a hammer crusher, which includes the following steps:
  • the grass raw materials are sent to a hammer crusher through a belt conveyor or other conveyor, and the hammer crusher includes a conveying feed section, a crushing section, and a discharge section.
  • the grass raw materials first enter the conveying and feeding section of the hammer crusher.
  • This section mainly serves as the conveying and feeding, and then enters the broken and smashing section.
  • the grass raw materials are subjected to the pressing force and tapping.
  • the grass material of 300-800mm length entering the hammer crusher is hammered off, so the hammer crusher first acts as a lawn mower; meanwhile, in the crushing and smashing section, The grass raw materials are squeezed, and the grass materials with a circular cross section are crushed, and the impurities such as leaves, awns, wheat grains, grains, and marrow are separated from the straw, and the separation rate is 70-90%.
  • the grass-like raw materials coming from the hammer crusher are broken up and discharged, and the pressed grass raw materials are broken up, and the contact surface between the raw materials and the cooking liquid is large, so that it is easy to penetrate, thereby accelerating off The process of lignin.
  • the grass material is discharged from the outlet of the hammer crusher.
  • the discharged grass raw material is 20-50 mm.
  • the hammer crusher in the present invention is a hammer mill for beneficiation or bark pulverization in the prior art.
  • the hammer crusher has a rotational speed of 500-800 rpm, and the grass raw material enters the hammer crusher at a speed of 0.5-1.0 m/s. If the rotational speed is too low or the feed is too fast, some grass raw materials are caused. Can not be completely paralyzed, affecting the penetration of the cooking liquid after the cooking, thereby affecting the quality of the pulp.
  • the outer layer of the grass material has a layer of wax and a layer of pulp inside the rod, in the general preparation method, when the outer layer is impregnated with the cooking liquid, the wax is quickly removed, but the grass material is removed.
  • the inner layer of the rod has air, so the cooking liquid is difficult to enter. After the grass raw material is cut and twisted by a hammer crusher, it is advantageous for sufficient impregnation of the grass raw material, and it is easy to obtain a good quality straw pulp after cooking.
  • the material after cutting and crushing is subjected to dust removal treatment, because the grass pieces after cutting contain impurities such as dust, sand, grass leaves, grass ears, etc., and most of the impurities are removed by dust removal treatment, so cooking after preparation is performed. In the process, the chemical consumption during cooking can be reduced, and the cooking time is also shortened accordingly.
  • the dust remover used in the dust removal treatment in the present invention may be a dust remover used in the preparation of grass raw materials in the prior art, including a roller dust remover, a double cone dust remover and a cyclone dust remover.
  • the dust remover is a cyclone. Dust collector.
  • the air volume is 30000-38000 m3/h, and the wind pressure is 210 mm water column. Under such conditions, the dust contained in the grass material can be largely removed, thereby reducing the burden of subsequent cooking. 3) Screening the raw materials subjected to dust removal. After the dust removal treatment, the grass raw materials often have coarse grass pieces and broken debris.
  • the cylindrical sieve of the present invention may be a cylindrical sieve used in the prior art for dry preparation of grass raw materials.
  • the cylindrical screen has a rotational speed of 18-29 r/min and an inclination angle of 6-12. It is also possible to improve on the basis of the above-mentioned existing cylindrical sieve, and design the inner sieve plate of the cylindrical sieve into a square sieve hole, the side length of which is 30-40 mm, and the diameter of the outer sieve sieve hole 4- 6mm, in the course of this screening process, large grass pieces and other fine impurities such as sand, dust, etc. are screened out to ensure the cleanness of the pulp prepared afterwards.
  • the impurity removal rate of the grass raw material is over 90%, and the general method for removing the dry preparation material has a removal rate of 50-70%, so that not only the dust in the slurry can be reduced, but also the The prepared slurry is clean, the yield is high, the yield is increased by 3-6% compared with the general method, and the production cost is reduced by 2-5% by the method of the present invention.
  • the pulp obtained after the decontamination in the present invention can be post-treated according to a prior art method such as secondary cooking and/or multiple bleaching treatment to obtain a high quality unbleached pulp or bleached chemical pulp.
  • a second object of the present invention is to provide a method for preparing another grass pulp, which is obtained by retorting a high-hardness pulp as a core, and then mixing, washing and dissolving, and oxygen delignification steps to obtain a high A pulp of quality, the pulp being unbleached.
  • a method of preparing grass pulp comprising:
  • the high-hardness pulp obtained in the step (1) is subjected to slurrying and washing to obtain a washed slurry;
  • the oxygen delignification described in the present invention comprises: feeding the obtained slurry into an oxygen delignification reaction tower, the temperature of the slurry at the inlet of the reaction tower is 90-100 ° C, and the pressure is 0.9-1.2 MPa; the temperature at the outlet is 95-105 ° C, the pressure is 0.2-0.4 MPa ; the oxygen delignification in the amount of alkali used is 2-4% of the absolute dry pulp, sodium oxygen The addition amount is 20 to 40 kg per ton of pulp for 60 to 90 minutes to obtain a slurry having a hardness of 10 to 14 potassium permanganate.
  • a third object of the present invention is to provide a method for preparing a grass pulp, wherein the grass pulp is a bleaching chemical pulp, and the method is to cook a high hardness pulp as a core, and then mix, wash and disintegrate, And the step of oxygen delignification to obtain a high quality pulp which is a bleached chemical pulp.
  • a method of preparing grass pulp comprising:
  • the high-hardness pulp obtained in the step (1) is subjected to slurrying and washing to obtain a washed slurry;
  • the bleaching according to the invention comprises: chlorination, alkali treatment and hypochlorite bleaching, chlorination: the amount of chlorine used is 2.5-3% of the dry pulp, the concentration of the pulp is 3-3.5%, and the bleaching temperature is 30. -45 ° C, bleaching time is 45-60 minutes; alkali treatment conditions are: the amount of sodium hydroxide added is 2-4% absolute dry pulp, the concentration of pulp is 10-12%, bleaching temperature is 50- 65 ° C, time is 100-150 minutes; hypochlorite bleaching: sodium hypochlorite is added in an amount of 2-4% of the dry pulp, bleaching temperature is 30-35 ° C, bleaching time is 100-150 minutes .
  • the bleaching according to the invention comprises: chlorination, alkali treatment and hydrogen peroxide bleaching, chlorination: the amount of chlorine used is 2.5-3% of the dry pulp, the concentration of the pulp is 3-3.5%, and the temperature of the bleaching is 30- 45 ° C, bleaching time is 45-60 minutes; alkali treatment conditions are: the amount of sodium hydroxide added is 2-4% absolute dry pulp, the concentration of pulp is 10-12%, bleaching temperature is 50-65 °C, time is 100-150 minutes; the hydrogen peroxide bleaching comprises: hydrogen peroxide is added in an amount of 4-6% of the dry pulp, the concentration of the pulp is 10-12%, and the pH is 11 - 12.5.
  • the amount of the chelating agent is 0.2% of the dry pulp amount, the amount of the magnesium sulfate protecting agent is 0.4% of the absolute dry pulp amount, the bleaching temperature is 95-99 ° C, and the bleaching time is 100-130 minutes.
  • the cooking according to the present invention comprises one of ammonium sulfite cooking, strontium-soda cooking, sulphate cooking or alkaline sodium smelting:
  • the amount of ammonium sulfite is 9-13% of the amount of the dry raw material
  • the amount of alkali is 9-15% based on the amount of dry raw materials
  • the amount of the dry raw material is 8-11% based on the amount of alkali
  • the amount of sodium hydroxide is 11-15% by weight of the dry raw material, and the amount of sodium sulfite is 2-6% by weight of the dry raw material.
  • the cooking according to the present invention comprises: one of ammonium sulfite cooking, strontium-soda cooking, kraft cooking or alkaline sodium cooking:
  • ammonium sulfite method is cooked as follows:
  • strontium-soda cooking It is heated by steam, heated to a temperature of 165-173 ° C, heated, deflated, and insulated for 160-210 minutes; the strontium-soda cooking is:
  • the alkaline sodium solution cooking comprises:
  • ammonium sulfite method is cooked as follows:
  • the grass material is filled into the cooking pot from the hot black liquor at a temperature of 120-140 ° C through a potter.
  • the lid is closed, and the cooking pot is replenished with a temperature of 130-16 CTC.
  • the air in the pot is discharged and boosted to 0.6-0.75 MPa.
  • the cooking liquid heating circulation pump and the tube heater of the system are turned on to raise the cooking liquid to 156-173 ° C, and the temperature is raised, kept and replaced for 180-220 minutes.
  • the slurry is sent to the spraying pot by the pump; wherein the amount of the ammonium sulfite is 9-15% of the amount of the dry raw material, and the amount of the sodium hydroxide is 0-8 of the dry raw material amount. %, liquid ratio is 1: 6-10;
  • the mash-soda cooking is as follows:
  • the grass plant material is charged into the cooking pot through a potter at a temperature of 120-140 ° C.
  • the lid is closed, and the cooking temperature is 130-16 CTC.
  • the air in the pot is discharged and raised to 0.4-0.6 MPa.
  • the cooking liquid heating circulation pump and the tube heater of the system are turned on to raise the cooking liquid to 147-165 ° C, and the temperature is raised, kept and replaced for 180 minutes.
  • the slurry is sent to the spraying pot by pumping; in the cooking agent, the amount of alkali is 9-17% of the dry raw material, and the liquid ratio is 1: 6-9. The amount is 0.5-0.8% of the amount of the dry raw material. ;
  • the kraft cooking is as follows:
  • the grass material is filled into the cooking pot from the hot black liquor with a temperature of 120-14 CTC through a potter.
  • the lid is closed, and the cooking pot is replenished with a temperature of 130-16 CTC.
  • the air in the pot is raised to 0.5-0.65 MPa.
  • the cooking liquid heating circulation pump and the tube heater of the system are turned on to raise the cooking liquid to 155-168 °C, and the temperature is raised, kept and replaced for 200-250 minutes, and finally the pump is used.
  • the alkaline sodium-sodium cooking comprises: charging the raw material of the grass plant material into the cooking pot through a potter from a hot black liquor having a temperature of 120-140 ° C, and closing the lid after cooking, to cook
  • the cooking temperature of the pot is 130-16CTC, and the air in the pot is discharged and raised to 0.45-0.6MPa.
  • the cooking liquid heating circulation pump and the tube heater of the system are turned on to raise the cooking liquid to 152-165 °C.
  • the amount of sodium hydroxide used in the cooking agent is 9-17% by weight of the dry raw material, sodium sulfite
  • the amount is 4-8% by weight of the dry raw material, and the amount of hydrazine is 0.04-0.08% by weight of the dry raw material, and the liquid ratio is 1:6-10.
  • the grass raw material may be impregnated: the grass fiber raw material is impregnated with the impregnation liquid to make the liquid ratio reach 1:2-4, and the spiral is above 85 ° C under normal pressure. Immersion and mixing in the impregnator for more than 10 minutes, wherein it is better to mix and mix for 10-40 minutes between 85-95 °C. In this way, the impregnation liquid is sufficiently contacted with the raw material to uniformly impregnate the raw material.
  • the immersion liquid may be a certain concentration of an alkali solution, such as a sodium hydroxide solution having a 4% dry raw material amount, or a mixture of a base and a black liquor, and the concentration of the black liquor used is 11-14° Be '(20 ° C).
  • an alkali solution such as a sodium hydroxide solution having a 4% dry raw material amount, or a mixture of a base and a black liquor, and the concentration of the black liquor used is 11-14° Be '(20 ° C).
  • the raw material is subjected to immersion pretreatment, so that the temperature and residual alkali of the black liquor are recycled and reused, thereby reducing energy and resource consumption. Due to the pre-treatment of the raw material, the delignification reaction during cooking is facilitated during the heat treatment. Prepare for the next cooking process.
  • the subsequent cooking process is a key step in pulping. Due to the differences in the structure, microstructure, chemical composition and lignin molecular structure of wood and grass materials, the delignification reaction process is also very high during the cooking process. Big difference.
  • the chemical composition of grasses is high in polypentose content, generally around 20%.
  • the content of sodium hydroxide is high and the content of lignin is low, but the content of ash is relatively high.
  • the ash is mainly silica. Due to the use of high temperature cooking and chemical cooking liquids, certain chemical changes occur in the raw materials of lignin, cellulose and hemicellulose, and other components, which are subject to degradation and damage to varying degrees.
  • the chemical cooking liquid is strictly controlled, and the amount and concentration of the chemical cooking liquid are reduced, thereby reducing the components required for pulping. Such as cellulose, hemicellulose degradation and damage.
  • the present invention adopts a method of minimizing the holding time, which shortens the time during which the grass plants are at a high temperature, thereby reducing the degradation of cellulose and hemicellulose in the grass material. Therefore, the method of the present invention maximizes the protection of the components required for pulping in the grass material, and greatly shortens the holding time, greatly reduces the energy consumption, and the pulping yield is greatly improved. It has reached 50-68%, thus greatly improving production efficiency.
  • the method of the present invention obtains a high-hardness pulp after cooking, and the hardness of the high-hardness pulp is a potassium permanganate value of 16-28, which corresponds to a Kappa number of 24-50, and a beating degree of 10-24 ° SR;
  • the hardness of the high hardness pulp is 18-27 of the potassium permanganate value corresponding to the Kappa price of 29-48;
  • the hardness of the high hardness pulp is most preferably the potassium permanganate value of 20 25 which corresponds to the Kappa price of 34-42.
  • the oxygen delignification of the present invention comprises: feeding the slurry obtained after cooking or the washed slurry into an oxygen delignification reaction tower, wherein the temperature of the slurry at the inlet of the reaction tower is 90-100° C, the pressure is 0.9-1.2 MPa; the temperature at the outlet is 95-105 ° C, the pressure is 0.2-0.6 MPa; the oxygen delignification in the amount of alkali is sodium hydroxide, the amount of dry pulp 2-4 ⁇ 3 ⁇ 4, oxygen is added in an amount of 20-40 kg per ton of pulp for 60-90 minutes, and an unbleached pulp having a hardness of 10-14 potassium permanganate is obtained.
  • the high-hardness slurry is heated to 70-8 CTC by a screw conveyor and sent to a slurry tube, and the slurry is subjected to quenching and tempering treatment in the slurry tube to remove the air in the slurry. Fluidization.
  • a magnesium salt such as magnesium sulfate or the like having a weight of 0.2 to 1% is added as a protective agent.
  • the invention adopts single-stage oxygen delignification, which is carried out under the condition of low temperature and relatively long time, mainly for the milder delignification reaction, and avoids degradation of cellulose as much as possible. Oxygen delignification is carried out under medium concentration conditions.
  • the main advantages of concentrated oxygen delignification are: less investment; due to the success of medium-concentration mixing and pumping technology, slurry processing is much easier than high concentration; low slurry concentration, less corrosion of equipment, no The danger of burning in oxygen.
  • the obtained high-hardness slurry is diluted with a certain pressure and sprayed into the discharge pot, and the pressure is
  • the concentration of the high-hardness slurry in the spray pot is 8-15%
  • the hardness of the potassium permanganate value is 16-28, which is equivalent to the Kaber price of 24-50
  • the degree of enthalpy is 10-24° SR.
  • the screw extruders are connected by a transfer pump, and the transfer pump conveys the high-hardness slurry in the spray pot to the inlet of the screw extruder, and the high-hardness pulp enters from the inlet of the screw extruder, after the slurry is squeezed, the above
  • the high-hardness slurry is sent out from the outlet of the extruder, and the concentration of the slurry sent is increased from 8-15% to 18-25%, and becomes a high-concentration high-hardness pulp at a temperature of 70-80 ° C.
  • the degree of hydrolysis is 15-28° SR. While the slurry is being squeezed, most of the black liquor is squeezed out and stored in the black liquor tank.
  • the slurry from the outlet of the extruder is diluted with black liquor displaced by washing in a subsequent process, the black liquor being 3-6° Be ' at 75 ° C, or water at 70 ° C. Dilute by dipping, and send the concentration of the slurry to 2.5-3% to the sieve for screening.
  • the squeezing according to the present invention comprises: introducing the high-hardness pulp having a concentration of 8-15% from the inlet of the extruder, and extruding the black liquor under the action of the pressing force to obtain a concentration of 18-25%.
  • Slurry slurry; the pulper is preferably a reduced diameter single screw extruder, double screw extruder or twin roller extruder.
  • the washing according to the present invention comprises: using the slurry after the slurry is one or two of a black liquor having a temperature of 70-8 CTC and a concentration of 3-6.2 ° Be ' and pH 8 - 8.3 or a clear water at a temperature of 70-8 CTC. Washing is carried out in a vacuum washer, a pressure washer or a horizontal belt washer.
  • the squeezer described in the present invention may be a variable diameter single screw extruder used in the prior art for extracting black liquor.
  • a squeezer for squeezing due to the large squeezing force generated during the squeezing process, the temperature rises rapidly, causing the fibers to separate, split, smash, crush, the primary wall is destroyed, and the fiber is absorbed enough.
  • the energy causes a large stress inside the fiber, and the reaction performance of the high-hardness pulp is greatly improved.
  • the fibers are fibrillated, and the impurities of the epidermis and interfibers are dissolved in the cooking black liquor, and the fiber purity is greatly improved by discharging through the liquid discharge tank.
  • the extruder according to the present invention may also be a twin-screw extruder or a twin-roller, which can achieve the same effect.
  • the washing in the present invention is to wash a high-hardness pulp having a hardness of 16-28 potassium permanganate equivalent to a Kappa number of 24-50, since the hardness of the pulp is high, It is easy to wash off the ash impurities and the like in the slurry, so that the slurry maintains a high degree of cleanliness.
  • the temperature of 70-8 CTC is 3-6.2 ° Be ' and the black liquor of pH 8-8.3 or one or both of the same temperature of the water is washed one or more times, and it is utilized.
  • the role of displacement, and diffusion are often carried out at the same time.
  • the diffusion effect is: the waste liquid existing inside the fiber can be diluted, causing the difference of the concentration of the solution inside and outside the fiber, so that the dissolved matter in the fiber is diffused, and then concentrated by pressure filtration to separate and diffuse. That is, the migration displacement effect is caused by the difference in concentration, that is, the high-concentration molecule having the higher concentration moves to the lower one, and the water molecule having the lower concentration also migrates to the higher concentration and is replaced.
  • the diffusion area is related to the type of pulp and its hardness.
  • the diffusion coefficient depends on the penetration of the solid matter dissolved in the waste liquid in the fiber. Capacity, which is related to washing temperature, viscosity and pressure.
  • the grass raw material described in the present invention is a combination of one or more of straw, wheat straw, cotton stalk, bagasse, reed or arundo.
  • a fourth object of the present invention is to provide a pulp prepared according to the above method, wherein the pulp is made of grasses, and the preparation method comprises the steps of: cooking to obtain a high-hardness pulp as a core, and then mixing, washing and dissolving, And the step of oxygen delignification to obtain a high quality pulp which is unbleached.
  • a pulp prepared according to the above method wherein the pulp is an unbleached pulp prepared by using grasses as raw materials, and the unbleached pulp has a crack length of 5.0-7.5 km and a tearing degree of 230-280 mN.
  • the unbleached pulp has a crack length of 6.5-7.5 km and a tear degree of 250-280 mN. .
  • the unbleached pulp has a whiteness of 25-45 ⁇ 3 ⁇ 4 ISO.
  • the number of folding resistances of the unbleached pulp is 40-90 times, and preferably the number of folding ends is 65-90 times.
  • the unbleached pulp has a freeness of 32-38 ° SR; preferably the freeness is 32-36 ° SR.
  • a high hardness slurry is prepared by reducing the amount of the cooking liquid and shortening the cooking time.
  • the reduction in the amount of chemical solution and the shortening of the cooking time during cooking greatly reduce the production cost of the enterprise, and the yield is greatly improved, thereby greatly improving the production efficiency.
  • the high hardness of the pulp obtained by cooking will minimize the degradation of cellulose and hemicellulose in the raw material, and the inherent length of the grass fiber is better maintained.
  • the high-hardness pulp of the present invention can be used as a raw material for preparing unbleached pulp, and the concentration of the liquid medicine used for cooking is lowered, and the cooking and holding time is also greatly shortened, thereby minimizing the amount of pulp in the pulp.
  • Desirable loss and degradation of cellulose and hemicellulose, and the unbleached pulp is not bleached, avoiding the degradation of cellulose and hemicellulose due to the bleaching step, maintaining the inherent length of the grass fibers . Therefore, the yield and strength of the unbleached pulp are improved.
  • a fifth object of the present invention is to provide a pulp prepared according to the above method, wherein the pulp is made of grasses, and the preparation method comprises the steps of: cooking high-hardness pulp as a core, and then mixing, washing and dissolving, And a step of oxygen delignification and bleaching to obtain a high quality pulp which is a bleached chemical pulp.
  • the pulp is a bleaching chemical pulp prepared from grass plants, and has a whiteness of 45-82% ISO, preferably the whiteness is 55-82% ISO, and more preferably the whiteness is 65-82 ⁇ 3 ⁇ 4 ISO, most preferably the whiteness is 75-82 ⁇ 3 ⁇ 4 ISO.
  • the bleaching chemical pulp of the present invention has a crack length of 4500-8000 m and a tear degree of 180-280 mN; preferably, the crack length is 5500-8000 m, and the tear degree is 220-280 mN.
  • the bleaching chemical pulp of the present invention has a folding resistance of 20 to 90 times; preferably, the folding endurance is 35 to 80 times.
  • the bleaching chemical pulp of the present invention has a freeness of 32-38 ° SR; preferably the freeness is 32-36 ° SR.
  • the crack length is about 3.8km
  • the tearing degree is only about 170mN
  • the crack length of the hardwood pulp is only 3.5-5.3km
  • the tearing degree can reach 440- 660mN, because the shape and size of the fiber cells of grass raw materials are much smaller than the cell shape and size of wood raw materials, but the content of miscellaneous cells that cause the physical strength of pulp is much higher than the corresponding wood raw materials, so this
  • the bleaching chemical pulp prepared by using the herbaceous plant as a raw material has a crack length longer than that of the prior art straw pulp, and even exceeds the hardwood pulp, although the tearing degree is not as good as the existing hardwood pulp, but the tearing degree is not as good as the existing hardwood pulp. It also greatly exceeds the existing straw and wheat straw pulp.
  • the folding resistance number is also an important indicator for characterizing pulp strength, which is mainly determined by the fiber length and the bonding force between the fibers.
  • pulp strength which is mainly determined by the fiber length and the bonding force between the fibers.
  • the fiber length is similar to that of hardwood pulp.
  • the wall cavity ratio of wheat straw cells is much higher than that of hardwood pulp and softwood pulp. It is generally considered that the fiber with higher wall cavity ratio is stiffer.
  • the resulting pulp has a low strength.
  • the number of folding resistance is 8 times, and the hardwood pulp is 10-23 times, and the number of folding resistance of the straw and wheat straw pulp of the present invention far exceeds them.
  • the bleaching chemical pulp prepared from grasses as raw materials has a beating degree of 32-36° SR, a crack length of 4500-8000 m, a folding resistance of 20-90 times, and a whiteness of 45-82 ⁇ 3 ⁇ 4 ISO.
  • the lignin removal rate is 84-98%.
  • the bleached chemical pulp can be used as a slurry for producing high quality cultural paper.
  • the raw materials used in the present invention are grasses, including straw, wheat straw, cotton stalks, bagasse, reeds, and arundos. These raw materials are abundant and low in price.
  • the bleached chemical pulp described in the present invention can be copied into general culture paper, and because of its excellent performance, it can be used with less wood pulp when preparing higher quality paper than the prior art. Therefore, in the increasingly scarce forest resources, the contradiction between high-quality paper demand and lack of timber resources has been greatly alleviated, and the production cost of enterprises has been reduced, which has brought good economic benefits to enterprises.
  • the wheat straw raw material is removed from the moldy part of the forage, and the wheat straw raw material having a length of 300-500 mm is fed through a belt conveyor from the inlet of the hammer crusher at a feeding speed of 0.8 m/s, and the hammer crusher has a rotation speed of 500 rpm.
  • the hammer crusher is a hammer crusher for stock preparation.
  • the wheat straw raw material discharged from the hammer crusher enters the cyclone dust collector, and is subjected to dust removal treatment under the condition that the air volume is 30000 m 3 /h and the wind pressure is 200 mm water column.
  • the straw raw material from the dust remover enters the cylindrical sieve for screening.
  • the screening speed of the cylindrical sieve is 19r/min, and the inclination angle is 8°.
  • the cylindrical sieve is a double-layer cylindrical sieve.
  • the preparation method has a removal rate of 90%.
  • the raw wheat straw material is put into the steaming ball, and the cooking liquid is added to the steaming ball.
  • the ammonium sulfite is added in an amount of 9 %, liquid ratio 1: 3, the first heating temperature is raised to 110 ° C, after 30 minutes of heat preservation and small steam release, the secondary heating is heated to 168 ° C, and the heating and holding time are 130 minutes.
  • the hardness of the high-hardness pulp obtained after cooking is a potassium permanganate value of 22 equivalent to a Kappa price of 35.5, a beating degree of 12.4° SR, and then a slurry with a variable-diameter single-screw extruder for high-hardness pulp before being squeezed.
  • the concentration is 8 ⁇ 3 ⁇ 4, the concentration of the slurry after squeezing is 15%, diluted with dilute black liquor to a concentration of 2.5-3.5%, and then washed with the oxygen lignin residue in the subsequent step using a vacuum washer in the prior art. .
  • the washed slurry was sent to a high-frequency disintegrator for dissolving, and after the disintegration, the concentration was adjusted to obtain a high-durability slurry having a concentration of 10%, and then the slurry was heated to 70 ° C by a screw conveyor and sent to a medium-thick slurry tube.
  • the slurry is firstly subjected to quenching and tempering treatment to remove the air in the slurry to be fluidized, and then sent to the oxygen delignification reaction tower through a centrifugal medium-concentration pump.
  • the slurry is mixed with the added oxygen of 20 kg per ton of pulp and the alkali solution of 4% of the dry pulp by sodium hydroxide before entering the reaction tower, and steam is introduced into the pipeline.
  • the slurry is heated to heat. After the slurry is thoroughly mixed in the mixer, it enters the oxygen delignification reaction tower.
  • the protective agent is magnesium sulfate, and the amount is 1% of the absolute dry pulp.
  • the inlet temperature is 95 ° C
  • the pressure is 0.9 Mpa
  • the residence time is 75 minutes.
  • the slurry was able to carry out a sufficient delignification reaction with a temperature of 100 ° C at the top of the column and a pressure of 0.4 MPa. After the treatment is completed, the slurry is sprayed into the slurry tank and diluted, and after washing, the unbleached pulp is obtained.
  • the unbleached pulp has a crack length of 6,800 m, a tearing degree of 250 mN, and a whiteness of 40 ⁇ 3 ⁇ 4 ISO.
  • the folding resistance is 60 times and the beating degree is 36° SR.
  • the above unbleached pulp was further bleached.
  • Chlorination The amount of chlorine used is 3% of the dry pulp, the concentration of the pulp is 3.2%, the temperature of bleaching is 40 ° C, and the bleaching time is 45 minutes.
  • the condition of alkali treatment is: the amount of sodium hydroxide added is absolutely 4% dry pulp, 12% pulp, bleaching temperature 55 ° C, 150 min; hypochlorite bleach: sodium hypochlorite is 4% dry pulp, bleaching temperature 30 C, bleaching time is 100 minutes.
  • a high quality grass pulp with a whiteness of 82% ISO, a crack length of 6,500 meters, a folding endurance of 45 times and a tearing degree of 220 mN can be obtained.
  • the straw raw material is removed from the moldy portion of the forage, and the straw raw material having a length of 500-800 mm is introduced from the inlet of the hammer crusher through a belt conveyor at a feeding speed of 0.6 m/s, and the hammer crusher has a rotation speed of 600 rpm.
  • the straw raw material having a length of 30-50 mm is discharged from the outlet of the hammer crusher.
  • the hammer crusher is a hammer crusher for stock preparation.
  • the straw raw material discharged from the hammer crusher enters the cyclone dust collector system, and is subjected to dust removal treatment under the conditions of an air volume of 35,000 m 3 /h and a wind pressure of 220 mm water column.
  • the straw raw material from the dust collector enters the cylindrical sieve for screening.
  • the screening speed is 20r/min and the inclination angle is 10°.
  • the cylindrical sieve is a double-layer cylindrical sieve.
  • the inner sieve of the cylindrical sieve has a square sieve hole of 30x30mm, and the outer sieve sieve has a diameter of 4mm.
  • the straw material from the discharge opening of the cylindrical sieve enters the digester for cooking.
  • the dry preparation rate of the method was 92%.
  • the prepared straw raw material is put into the cooking pot, and the cooking liquid is added to the cooking pot.
  • the ammonium sulfite is added in an amount of 13% of the absolute dry material, the liquid ratio is 1:4, and the first heating is heated to 120 °C. , heat preservation and small steam release for 65 minutes, secondary heating to 168 V, heating and holding for 145 minutes.
  • the hardness of the high-hardness pulp obtained after cooking is 16 equivalent to the Kappa price of 23, and the beating degree is 24° SR, and then the slurry is squeezed by a double-screw extruder, and the slurry concentration is 10% before the slurry is squeezed.
  • the concentration of the slurry was 26%, and the mixture was washed in a pressure washer with a black liquor having a temperature of 75 ° C and a concentration of 5 ° Be 'pH 8.
  • the fiber separator was used for dissolving, and after dissolving, the high-density pulp having a concentration of 10% was adjusted, and then the slurry was heated to 70 ° C by a screw conveyor and sent to a medium-thick pulp tube.
  • the slurry is firstly subjected to quenching and tempering treatment to remove the air in the slurry to be fluidized, and then sent to the oxygen delignification reaction tower through a centrifugal medium-concentration pump.
  • the slurry is in the pipeline with the added oxygen of 32 kg per ton of pulp before entering the reaction tower.
  • the slurry is mixed with an alkali solution containing 3.5% of the dry pulp by sodium hydroxide, and steam is heated in the line to heat the slurry.
  • the protective agent is magnesium sulfate, and the amount is 1% of the absolute dry pulp.
  • the inlet temperature is 90 ° C
  • the pressure is l.lMpa
  • the residence time is 85 minutes.
  • the slurry was allowed to undergo a sufficient delignification reaction at a temperature of 100 ° C at the top of the column and a pressure of 0.2 MPa.
  • the slurry is sprayed into the slurry tank and diluted, and after washing, the unbleached pulp is obtained.
  • the unbleached pulp has a crack length of 6000 m, a tearing degree of 230 mN, and a whiteness of 35 ⁇ 3 ⁇ 4 ISO.
  • the folding resistance is 90 times and the beating degree is 32° SR.
  • the above unbleached pulp is further bleached, chlorinated, alkali treated and hydrogen peroxide bleached, chlorinated: the amount of chlorine used is 2.5% of the dry pulp, the concentration of the pulp is 3.5%, and the bleaching temperature is 45 ° C.
  • the bleaching time is 60 minutes; the conditions of the alkali treatment are: the amount of sodium hydroxide added is 4% of the absolute dry pulp, the concentration of the pulp is 10%, the bleaching temperature is 50 ° C, and the time is 100 minutes; Hydrogen peroxide bleaching includes: Hydrogen peroxide is added in an amount of 4% of the dry pulp, the concentration of the pulp is 10%, the pH is 11, the amount of the chelating agent is 0.2% of the dry pulp, and the amount of the magnesium sulfate protecting agent is The dry pulp amount is 0.4%, the bleaching temperature is 95 ° C, and the bleaching time is 130 minutes. After bleaching, a high-quality straw pulp with a whiteness of 74% ISO, a crack length of 5,500 meters, a folding resistance of 35 times, and a tearing degree of 280 mN can be obtained.
  • the cotton stalk material having a length of 400-700 mm is fed through a belt conveyor from the inlet of the hammer crusher at a feeding speed of 0.5 m/s.
  • the speed of the hammer crusher is 740 rpm, and the raw material enters the hammer crusher.
  • the cotton stalk material having a length of 15-35 mm is discharged from the outlet of the hammer crusher.
  • the hammer crusher is a hammer crusher for stock preparation.
  • the cotton stalk raw material discharged from the hammer crusher enters the cyclone dust collector, and is subjected to dust removal treatment under the conditions of an air volume of 32,000 m 3 /h and a wind pressure of 210 mm water column.
  • the cotton stalk material from the dust remover enters the cylindrical sieve for screening.
  • the screening speed is 23r/min and the inclination angle is 12°.
  • the cylindrical sieve is a double-layer cylindrical sieve.
  • the inner sieve of the cylindrical sieve has a diameter of 30 mm, and the outer sieve has a diameter of 5 mm.
  • the cotton stalk material coming out of the discharge port of the cylindrical sieve enters the digester for cooking.
  • the dry preparation rate was 91.5% by this method.
  • the prepared cotton stalk raw material is put into the steaming ball, and the cooking liquid is added to the steaming ball.
  • the ammonium sulfite is added in an amount of 11% of the absolute dry material, the liquid ratio is 1:2, and the first heating is heated to 130 °C. , heat preservation and small steam release for 55 minutes, when the secondary heating is raised to a temperature of 173, the temperature is raised and kept for 140 minutes.
  • the high hardness pulp with a hardness of 19 equivalent to the Kappa price of 28 is obtained by boiling, and the degree of beating is 16.3° SR.
  • the concentration is 10%, and the single-screw extruder for the black liquor extraction in the prior art is squeezed and squeezed.
  • a high-durability slurry having a concentration of 32% was obtained, and the black liquor having a temperature of 70 ° C and a concentration of 6.2 ° Be ' and pH 8 - 8.3 was diluted to 2.5%, and then sent to a vacuum washer for washing. After washing, the slurry was disintegrated by a disc grinder, and after the slurried slurry was adjusted to a concentration of 13%, the slurry was heated to 70 ° C by a screw conveyor and sent to a medium consistency slurry tube.
  • the slurry is firstly subjected to quenching and tempering treatment to remove the air in the slurry to be fluidized, and then sent to the oxygen delignification reaction tower through a centrifugal medium-concentration pump.
  • the slurry is mixed with the added oxygen of 38 kg per ton of pulp and the alkali solution of 3% by weight of sodium hydroxide in the pipeline before entering the reaction tower, and steam is introduced into the pipeline.
  • the slurry is heated to heat. After the slurry is thoroughly mixed in the mixer, it enters the oxygen delignification reaction tower.
  • the protective agent is magnesium sulfate, and the amount added is 0.8% by weight of the dry pulp.
  • the inlet temperature is 98 ° C
  • the pressure is 1.05 Mpa
  • the residence time is 85 minutes.
  • the slurry was able to carry out a sufficient delignification reaction with a temperature of 102 ° C at the top of the column and a pressure of 0.4 MPa.
  • the slurry is sprayed into the slurry tank and diluted, and after washing, the unbleached pulp is obtained.
  • the unbleached pulp has a crack length of 7,500 meters and a tearing degree of 240 mN.
  • the whiteness is 45 ⁇ 3 ⁇ 4ISO
  • the folding resistance is 70 times
  • the beating degree is 34° SR.
  • the above unbleached pulp is further subjected to bleaching treatment.
  • Chlorination The amount of chlorine used is 2.8% of the dry pulp, the concentration of the pulp is 3.5%, the bleaching temperature is 45 ° C, and the bleaching time is 55 minutes.
  • the condition of the alkali treatment is: the amount of sodium hydroxide added is absolutely The dry pulp volume is 4%, the pulp concentration is 12%, the bleaching temperature is 65 ° C, and the time is 120 minutes.
  • Hypochlorite bleaching The sodium hypochlorite is added in an amount of 1% of the absolute dry pulp, and the bleaching temperature is 35°. C, bleaching time is 150 minutes.
  • a high-quality cotton stalk slurry with a whiteness of 80% ISO, a crack length of 7,000 m, a folding resistance of 50 times, and a tearing degree of 180 mN can be obtained.
  • the reed raw material having a length of 600-800 mm is introduced from the inlet of the hammer crusher through a belt conveyor at a feeding speed of 0.9 m/s, and the speed of the hammer crusher is 740 rpm, when the raw material enters the hammer crusher.
  • the reed material having a length of 15-50 mm is discharged from the outlet of the hammer crusher.
  • the hammer crusher is a hammer crusher for stock preparation.
  • the raw material of the reed discharged from the hammer crusher enters the cyclone dust collector, and is subjected to dust removal treatment under the condition that the air volume is 38000 m 3 /h and the wind pressure is 230 mm water column.
  • the raw materials of the reed from the dust collector enter the cylindrical sieve for screening.
  • the screening speed is 21r/min and the inclination angle is 11°.
  • the cylindrical sieve is a double-layer cylindrical sieve which plays a screening role in the preparation.
  • the inner sieve of the cylindrical sieve has a sieve hole of 30x30mm, and the outer sieve has a diameter of 4mm.
  • the reed material coming out of the discharge port of the cylindrical sieve enters the digester for cooking.
  • the prepared reed is put into the steaming ball, and the cooking agent is added to the batch spherical digester.
  • the ammonium sulfite is added in an amount of 10% of the absolute dry material, and the sodium hydroxide is 8% of the absolute dry material. 1 : 3, the first heating is heated to 140 ° C, the heat preservation and small steam release for 45 minutes, the second heating to the temperature of 175 ° C, heating and holding for 155 minutes.
  • a high-hardness pulp having a hardness of 28 and a beating degree of 10° SR is obtained, and then the high-hardness slurry is sent to a conventional single-screw extruder for extracting black liquor in the prior art for slurrying, and concentration is obtained after slurrying.
  • concentration is obtained after slurrying.
  • the slurry from the extruder is diluted with dilute black liquor to a concentration of 2.5-3.0%, sent to the sieve for coarse slurry screening, and the sieve loss is 0.2%.
  • the high-concentration cleaner removes impurities and loses 0.1%.
  • the slurry obtained after the removal is washed into a horizontal belt washer for washing.
  • the slurry concentration during washing is 2.0%, and the concentration of the slurry from the washer is 9 %, washing with a black liquor having a concentration of 4 ° Be ' and pH 8 - 8.3 in a horizontal belt washer. Maintaining 68-70 ° C during the washing process, and then transporting it to the disintegrating machine for dissolving.
  • the re-pulping degree of the reed pulp before the disintegration is 24 ° SR, and the re-slurry re-pulping pulp has a beating degree of 27 0 SR, which is adjusted to After 10%, the slurry was heated to 80 ° C by a screw conveyor and transferred to a medium consistency slurry tube.
  • the slurry is firstly subjected to quenching and tempering treatment to remove the air in the slurry to be fluidized, and then transferred to the oxygen delignification reaction tower through a centrifugal medium-concentration pump.
  • the slurry is mixed with the added oxygen of 30 kg per ton of pulp and the amount of alkali in the pipeline before the entry into the reaction tower, and the amount of alkali is mixed with 4% alkali solution of sodium hydroxide, and steam is introduced into the pipeline.
  • the slurry is heated to heat. After the slurry is thoroughly mixed in the mixer, it enters the oxygen delignification reaction tower.
  • the protective agent is magnesium sulfate, and the amount is 1% by weight of the absolute dry pulp.
  • the inlet temperature is 102 V
  • the pressure is 1.2 Mpa
  • the residence time is 90 minutes.
  • the slurry was able to carry out a sufficient delignification reaction with a temperature of 105 ° C at the top of the column and a pressure of 0.5 MPa.
  • the slurry is sprayed into the slurry tank and diluted, and after washing, the unbleached pulp is obtained.
  • the unbleached pulp has a crack length of 7,500 m, a tearing degree of 260 mN, and a whiteness of 55 ⁇ 3 ⁇ 4 ISO.
  • the folding resistance is 60 times and the beating degree is 36° SR.
  • the above unbleached pulp was subjected to CEP three-stage bleaching treatment.
  • Chlorination The amount of chlorine used is 3% of the dry pulp, the concentration of the pulp is 3%, the temperature of bleaching is 38 ° C, and the bleaching time is 60 minutes.
  • the condition of alkali treatment is: the amount of sodium hydroxide added is absolutely The dry pulp volume is 3%, the pulp concentration is 10%, the bleaching temperature is 60 ° C, and the time is 120 minutes; hydrogen peroxide bleaching: the amount of hydrogen peroxide added is absolutely The dry pulp amount is 5%, the pulp concentration is 10%, the pH is 11.8, the chelating agent is 0.2%, the protective agent is 0.4 ⁇ 3 ⁇ 4 of magnesium sulfate, the bleaching temperature is 97 ° C, and the bleaching time is 120 minutes.
  • the bleaching chemical pulp has a whiteness of 78 ⁇ 3 ⁇ 4ISO, a crack length of 8000 m, a folding endurance of 70 times, and a tearing degree of 250 mN.
  • the straw raw material having a length of 300-500 mm is passed through a belt conveyor at a feeding speed of 1.0 m/s from the inlet of the hammer crusher, and the speed of the hammer crusher is 720 rpm, and the raw material enters the hammer crusher.
  • the straw raw material having a length of 20-35 mm is discharged from the outlet of the hammer crusher.
  • the straw raw material discharged from the hammer crusher enters the cyclone dust collector, and is subjected to dust removal treatment under the condition that the air volume is 36500 m 3 /h and the wind pressure is 215 mm water column.
  • the straw raw material from the dust collector enters the cylindrical sieve for screening.
  • the first section of the screening cylinder screen has a rotation speed of 19r/ m in and the inclination angle is 12°; the second section of the screen cylinder screen rotates at 22r/ m in , the tilt angle is 10°.
  • the cylindrical sieve is a double-layer cylindrical sieve which plays a screening role in the preparation.
  • the cylindrical sieve of the present invention is a double-layer cylindrical sieve, the inner sieve of the cylindrical sieve has a square hole of 30 X 30 mm, and the outer sieve sieve has a diameter of 4 mm.
  • the dry preparation rate was 95% by this method.
  • the prepared wheat straw is put into the cooking pot, and the cooking liquid is added to the cooking pot, wherein the alkali amount is 15% of the amount of the dry raw material based on the sodium hydroxide, and the amount of the cerium added is 0.5% of the dry raw material amount. . , liquid ratio 1 : 2, the first heating to 140 ° C, heat preservation and small steam for 30 minutes, secondary heating to 160 ° C, heating and holding time of 160 minutes.
  • a high-hardness pulp with a hardness of 20 equivalent to a Kappa price of 32 is obtained, and the degree of beating is 13.8° SR. Then, the high-hardness pulp is sent to the prior art to reduce the diameter of the single-screw extruder for the black liquor.
  • the slurry from the extruder is diluted with a temperature of 70-8 CTC of 6.2 ° Be ' and a diluted black liquor of pH 8-8.3 to a concentration of 2.5%, sent to a sieve for coarse filtration, and sieved.
  • the loss was 0.6%, and the impurities were removed by a high concentration separator to lose 0.3%.
  • the slurry obtained after the slag removal was then washed into a vacuum washer.
  • the concentration of the pulp coming out of the washing machine is 12%, and it is kept at 70-80 °C during the washing process, and then sent to the disc grinding and dispersing machine for dissolving.
  • the degree of beating of the straw pulp before the disintegration is 32° SR, after the disintegration
  • the straw pulp has a beating degree of 33 ° SR.
  • the slurry is heated to 68 ° C by a screw conveyor and transferred to a medium consistency slurry tube.
  • the slurry is firstly subjected to quenching and tempering treatment to remove the air in the slurry to be fluidized, and then sent to the oxygen delignification reaction tower through a centrifugal medium-concentration pump.
  • the slurry is mixed with the added oxygen of 35 kg per ton of pulp and the amount of alkali by the amount of sodium hydroxide in a 4% alkaline solution before entering the reaction tower, and steam is introduced into the pipeline.
  • the slurry is heated to heat. After the slurry is thoroughly mixed in the mixer, it enters the oxygen delignification reaction tower.
  • the protective agent is magnesium sulfate, and the amount is 1% by weight of the absolute dry pulp.
  • the inlet temperature is 100 ° C
  • the pressure is l.lMpa
  • the residence time is 90 minutes.
  • the slurry was allowed to carry out a sufficient delignification reaction at a temperature of 104 ° C and a pressure of 0.4 MPa.
  • the slurry is sprayed into the slurry tank and diluted, and after washing, the unbleached pulp is obtained.
  • the unbleached pulp has a crack length of 5000 m, a tear degree of 270 mN, and a whiteness of 403 ⁇ 4>ISO.
  • the folding resistance is 65 times and the beating degree is 35 ° SR.
  • the above unbleached pulp is further subjected to bleaching treatment.
  • the bleaching includes: chlorination, alkali treatment and hydrogen peroxide bleaching, chlorination: the amount of chlorine used is 2.5% of the dry pulp, the concentration of the pulp is 3.5%, the bleaching temperature is 40 ° C, and the bleaching time is 60 minutes; the conditions of the alkali treatment are: the amount of sodium hydroxide added is 4% of dry pulp, the concentration of pulp is 10%, the bleaching temperature is 65 ° C, and the time is 120 minutes; the hydrogen peroxide bleaching includes : The amount of hydrogen peroxide added is 5% of the absolute dry pulp, the concentration of the slurry is 10%, the pH is 11, the amount of the chelating agent is 0.2% of the dry pulp, and the amount of the magnesium sulfate protectant is the dry pulp. 0.4%, bleaching temperature is 99 ° C, bleaching time is 120 minutes.
  • the whiteness of the obtained bleached chemical pulp is 65% ISO, and the crack length is 4500m
  • the raw material discharged from the hammer crusher enters the cyclone dust collector, and is subjected to dust removal treatment under the conditions of an air volume of 31,000 m 3 /h and a wind pressure of 255 mm water column.
  • the raw materials from the dust collector enter the cylindrical sieve for screening.
  • the first section of the screening cylinder screen has a rotation speed of 20r/min and the inclination angle is 10°; the second section of the screening cylinder screen has a rotation speed of 22r/min, the inclination angle. It is 9°.
  • the cylindrical sieve is a double-layer cylindrical sieve prepared.
  • the cylindrical sieve of the present invention is a double-layer cylindrical sieve.
  • the inner sieve of the cylindrical sieve has a square hole of 30 X 30 mm, and the outer sieve sieve has a diameter of 6 mm. Finally, the material coming out of the discharge port of the cylindrical sieve enters the digester for cooking.
  • the dry preparation rate was 94% by this method.
  • the prepared reed and the Luzhu are mixed at a mass ratio of 1:4, they are put into a spherical digester, and the cooking liquid is added to the spherical digester, and the amount of the alkali is used to determine the amount of the dry raw material. 9 % of the amount of niobium added is 0.8% of the amount of dry raw materials.
  • liquid ratio 1 : 4 the first heating to 135 ° C, heat preservation and small steam for 60 minutes, the second heating to 165 ° C, the temperature rise and holding time is 130 minutes.
  • a high-hardness pulp having a hardness of 20 equivalent to a Kappa price of 30 is obtained, and the degree of beating is 14.5° SR, and the concentration of the high-hardness pulp is adjusted to 14%, and then the high-hardness slurry is sent to the prior art for extracting black liquor. 5-3. 0%, sent to the sieve for coarse slurry screening, skipping. The slurry from the extruder is diluted with dilute black liquor to a concentration of 2. 5-3. 0%.
  • the sieve loss is 0.6%, and the impurities are removed by a high-concentration cleaner to lose 0.3%, and then washed by a conventional washing method, and then the slurry is heated to 78 ° C by a screw conveyor and conveyed to medium concentration. Slurry tube.
  • the slurry is firstly subjected to quenching and tempering treatment to remove the air in the slurry to be fluidized, and then sent to the oxygen delignification reaction tower through a centrifugal medium-concentration pump.
  • the slurry is mixed with the added oxygen and the alkali content of the 35 kg per ton of the slurry before the flow into the reaction column is 2.5% of the alkaline solution in terms of sodium hydroxide, and is in the pipeline.
  • the slurry was heated to heat by steaming. After that, the slurry is thoroughly mixed in the mixer and then enters the oxygen delignification reaction tower.
  • the protective agent is magnesium sulfate, and the amount is 1% by weight of the dry pulp.
  • the inlet temperature is 100 ° C
  • the pressure is 1. 2 Mpa
  • the residence time is 80 minutes. 6MPa ⁇
  • the granules were maintained at a pressure of 0. 6MPa.
  • the slurry is sprayed into a slurry tank and diluted, and after washing, the unbleached pulp is obtained.
  • the unbleached pulp has a crack length of 5,800 meters, a tearing degree of 260 N, a whiteness of 42 ⁇ 3 ⁇ 4 ISO, a folding resistance of 50 times, and a beating degree of 35 ° SR.
  • the above unbleached pulp is further subjected to bleaching treatment.
  • Chlorination The amount of chlorine used is 2.5% of the dry pulp, the concentration of the pulp is 3%, and the temperature of bleaching is 35. C, bleaching time is 60 minutes; alkali treatment conditions are: adding sodium hydroxide in an amount of 2% dry pulp, pulp concentration of 12%, bleaching temperature of 50 ° C, time of 130 minutes; Acid bleaching: Sodium hypochlorite is added in an amount of 2% of the dry pulp, the bleaching temperature is 35 ° C, and the bleaching time is 120 minutes.
  • the bleaching chemical pulp has a whiteness of 72% IS0, a crack length of 5500 m, a folding endurance of 40 times, and a tearing degree of 260 mN.
  • Example 7 The bagasse was passed through a belt conveyor at a feeding speed of 0.65 m/s from the inlet of the hammer crusher, the hammer crusher was rotated at 750 rpm, and the raw material was cut and crushed when entering the hammer crusher. Thereafter, the bagasse material having a length of 20-50 mm is discharged from the outlet of the hammer crusher. The hammer crusher of the hammer crusher is prepared. The bagasse material discharged from the hammer crusher enters the cyclone dust collector, and is subjected to dust removal treatment under the conditions of an air volume of 34,000 m 3 /h and a wind pressure of 225 mm water column. The bagasse raw material from the dust collector enters the cylindrical sieve for screening.
  • the first section of the screening cylinder screen has a rotation speed of 18r/min and the inclination angle is 10°; the second section of the screening cylinder screen has a rotation speed of 21r/min.
  • the tilt angle is 9°.
  • the cylindrical sieve is a double-layer cylindrical sieve in the preparation.
  • the cylindrical sieve of the present invention is a double-layer cylindrical sieve, the inner sieve of the cylindrical sieve has a diameter of 30 mm, and the outer sieve has a diameter of 4 mm.
  • the bagasse material coming out of the discharge port of the cylindrical sieve enters the digester for cooking.
  • the dry preparation rate was 93% by this method.
  • the bagasse after the preparation of the bagasse is charged into the cooking pot, and the cooking liquid is added to the cooking pot, and the alkalitity is the ratio of the degree of vulcanization of the dry raw material to the liquid ratio of 1:4, the first heating is heated. At 110 ° C, heat and small steam at this temperature for 30 minutes, and heat up for 30 minutes to a temperature of 165 ° C for 90 minutes. After cooking, a high-hardness pulp having a hardness of 24 equivalent to a Kappa price of 41 is obtained, and the degree of beating is 10° SR, and then the high-hardness pulp is sent to a conventional single-screw extruder for extracting black liquor in the prior art for sintering.
  • a high-density slurry having a concentration of 28% was obtained after the squeezing, and the black liquor having a concentration of 6.2 ° Be ' and pH 8.3 was washed in a horizontal belt washer.
  • the resulting slurry after washing was transferred to a disc grinder for disintegration, and then the slurry was heated to 70 ° C by a screw conveyor and transferred to a medium consistency tube.
  • the slurry is first tempered in the middle thick slurry tube to remove the air in the slurry to be fluidized, and then sent to the oxygen delignification reaction column through a centrifugal medium-concentration pump.
  • the slurry is mixed with the added oxygen of 20 kg per ton of pulp and the alkali content in the pipeline before entering the reaction tower is 4% alkali solution by weight of sodium hydroxide, and steam is introduced into the pipeline.
  • the slurry is heated to heat. After the slurry is thoroughly mixed in the mixer, it enters the oxygen delignification reaction tower.
  • the protective agent is magnesium sulfate, and the amount is 1.3% by weight of the absolute dry pulp.
  • the inlet temperature is 95 ° C
  • the pressure is 0.95 MPa
  • the residence time is 70 minutes.
  • the slurry was able to carry out a sufficient delignification reaction with a temperature of 10 rC at the top of the column and a pressure of 0.3 MPa.
  • the slurry is sprayed into the slurry tank and diluted, and after washing, the unbleached pulp is obtained.
  • the unbleached pulp has a crack length of 6,800 m, a tearing degree of 230 mN, and a whiteness of 45 ⁇ 3 ⁇ 4 ISO.
  • the folding resistance is 55 times and the beating degree is 33 ° SR.
  • the above unbleached pulp was further bleached.
  • Chlorination The amount of chlorine used is 3% of the dry pulp, the concentration of the pulp is 3.5%, the bleaching temperature is 45 ° C, and the bleaching time is 55 minutes.
  • the condition of the alkali treatment is: the amount of sodium hydroxide added is absolutely 2% dry pulp, 10% pulp, bleaching temperature 63 ° C, time 120 minutes; hypochlorite bleaching: sodium hypochlorite is added in 4% dry pulp, bleaching temperature is 35 ° C, bleaching time is 150 minutes.
  • the bleaching chemical pulp has a whiteness of 82% ISO, a crack length of 6,500 meters, a folding endurance of 45 times, and a tearing degree of 190 mN.
  • Example 8 The cotton stalk was prepared according to the method of Example 1 and then charged into a digester.
  • the retort was added to the retort.
  • the amount of alkali was 11% of the amount of dry raw material based on sodium hydroxide.
  • the degree of sulfidation was 5%, liquid ratio 1: 2, the first heating to 140 °C, heat and small steam for 65 minutes, secondary heating to 165 ° C, heating and holding for 100 minutes.
  • the hardness is 25
  • the high hardness pulp of Kaber price 43 is used, the degree of beating is 10° SR, and then the high hardness pulp is sent to the single-screw extruder for extracting black liquor in the prior art for slurrying, and the concentration is 32% after being squeezed.
  • the high-hardness pulp is washed in a horizontal belt washer with a diluted black liquor at a temperature of 80 ° C and a portion of the same temperature water.
  • the slurry concentration after washing was adjusted to 12%, and after dissolving by a disc refiner, the slurry was heated by a screw conveyor to 65 ° C and transferred to a medium consistency tube.
  • the slurry is firstly subjected to quenching and tempering treatment to remove the air in the slurry to be fluidized, and then sent to the oxygen delignification reaction tower through a centrifugal medium-concentration pump.
  • the slurry is mixed with the added oxygen of 20 kg per ton of pulp and the alkali content of the alkali solution of 3.5% by weight of sodium hydroxide in the pipeline before entering the reaction tower, and steam is introduced into the pipeline.
  • the slurry is heated to heat.
  • the protective agent is magnesium sulfate, and the amount is 1.5% by weight of the absolute dry pulp.
  • the inlet temperature is 90 ° C
  • the pressure is l.lMpa
  • the residence time is 60 minutes.
  • the slurry was allowed to carry out a sufficient delignification reaction, the temperature at the top of the column was 100 ° C, and the pressure was maintained at 0.4 MPa.
  • the slurry is sprayed into the slurry tank and diluted, and after washing, the unbleached pulp is obtained.
  • the unbleached pulp has a crack length of 5,700 meters, a tearing degree of 245 mN, and a whiteness of 303 ⁇ 4>ISO.
  • the folding resistance is 60 times and the beating degree is 35° SR.
  • the above unbleached pulp was further bleached.
  • the traditional CEH three-stage bleaching is used later, specifically: the chlorine content of the C section is 3% of the absolute dry pulp, the concentration of the pulp is 3.5%, the bleaching temperature is 42 ° C, and the bleaching time is 45 minutes; The amount of sodium hydroxide is 3% of dry pulp, the concentration of pulp is 11%, the bleaching temperature is 50 ° C, and the time is 150 minutes; the amount of sodium H-sodium hypochlorite is 2.5% of the dry pulp, the temperature of bleaching At 30 ° C, the bleaching time is 150 minutes, and a high quality grass pulp with a whiteness of 75% ISO, a crack length of 5,500 m and a folding resistance of 55 times is obtained.
  • Example 9 Straw and wheat straw were prepared according to Example 2 and Example 3, respectively, and then charged into a cooking pot at a mass ratio of 1:4, and a cooking agent was added to the cooking pot, and the amount of alkali was determined by sodium hydroxide. 11% of the dry raw material, the sulfidation degree is 5%, the liquid ratio is 1: 4, the first heating is heated to 110 ° C, the heat preservation and small steam release are 50 minutes, the secondary heating is heated to 168 ° C, and the temperature is raised. The holding time is 150 minutes. After cooking, the hardness is 19, which is equivalent to the high hardness pulp of Kappa price 29.
  • the degree of beating is 16° SR, and then sent to the conventional single-screw extruder for extracting black liquor for slurrying.
  • the concentration before extrusion is 12%
  • the concentration of the slurry from the extruder is 25%
  • diluted with dilute black liquor to the concentration of the pulp is 3.0%
  • sent to the sieve for coarse slurry screening the sieve loss is 0.2%
  • the slag remover removes impurities and loses 0.1%.
  • the slurry obtained after the slag removal is then sent to a vacuum washer for washing with a diluted black liquor at a temperature of about 75 ° C and a portion of the same temperature.
  • the slurry concentration during washing is 3.0%.
  • the concentration of the slurry coming out of the washer is 10%, the temperature during the washing process is about 72 ° C, and then it is sent to the high-frequency disintegrator for dissolving, and the slurry is then subjected to quenching and tempering through the middle thick slurry tube.
  • the air in the slurry is removed to make it fluidized, and then sent to the oxygen delignification reaction tower through a centrifugal medium-concentration pump.
  • the slurry is mixed with the added oxygen of 25 kg per ton of pulp and the alkali solution of 2% by weight of sodium hydroxide on the basis of sodium hydroxide before entering the reaction tower, and steam is introduced into the pipeline.
  • the slurry is heated to heat.
  • the protective agent is magnesium sulfate, and the amount is 0.6% of the weight of the dry pulp.
  • the inlet temperature is 99 ° C
  • the pressure is l.lMPa
  • the residence rate is 70.
  • the slurry was allowed to undergo a sufficient delignification reaction at a temperature of 104 ° C and a pressure of 0.38 MPa.
  • the slurry is sprayed into the slurry tank and diluted, and then washed to obtain the unbleached pulp.
  • the unbleached pulp has a crack length of 6,500 meters, a tearing degree of 280 mN, and a whiteness of 25 ⁇ 3 ⁇ 4ISO, the number of folding resistance is 65, and the degree of beating is 35 ° SR.
  • the above unbleached pulp was then bleached.
  • the bleaching is specifically as follows: H-sodium hypochlorite is added in an amount of 2.5% of the dry pulp, the bleaching temperature is 32 ° C, and the bleaching time is 150 minutes, and the whiteness is 45% ISO, and the crack length is 6300.
  • Straw and wheat straw with a mass ratio of 1:5 were prepared according to Example 4 and Example 5, respectively.
  • the rice straw was mixed and filled with a hot black liquor having a temperature of 135 ° C through a potter into a vertical cooking pot.
  • Liquid ratio 1:8 close the lid when it is full, add the cooking agent at a temperature of 145 °C to the cooking pot, and use the alkali amount to be 13% of the amount of dry raw material based on sodium hydroxide.
  • the air is discharged and boosted to 0.6 MPa.
  • the cooking liquid circulation pump and the tube heater of the cooking pot are turned on to heat the cooking liquid to 155 ° C, and the temperature is raised and kept for 160 minutes.
  • the hot black liquor is replaced with a dilute black liquor and sent to a hot black liquor tank.
  • a high-hardness pulp having a hardness of 19 equivalent to a Kappa number of 29 is obtained, and the degree of beating is 16° SR, and then sent to a conventional black liquor for extraction.
  • the variable-diameter single-screw extruder is used for squeezing, the concentration before squeezing is 8%, the concentration of the slurry coming out from the squeezing machine is 22%, and then diluted with dilute black liquor to the concentration of the pulp to 3.0%, To the sieve for coarse slurry screening, the sieve loss is 0.2%, and the impurities are removed by the high-concentration cleaner to lose 0.1%.
  • the slurry obtained after the slag is removed into the vacuum washer using a temperature of 75 °C.
  • the black liquor and part of the water at the same temperature are washed, the concentration of the pulp coming out of the washer is 9%, the temperature during the washing process is about 75 ° C, and then it is sent to the high-frequency disintegrator for dissolving, and then the pulp is re-dissolved.
  • the medium in the slurry is firstly subjected to quenching and tempering treatment to remove the air in the slurry to be fluidized, and then transferred to the oxygen delignification reaction tower through a centrifugal medium-concentration pump.
  • the slurry is mixed with the added oxygen of 30 kg per ton of pulp and the alkali content of the alkali solution of 3% by weight of sodium hydroxide in the pipeline before entering the reaction tower, and steam is introduced into the pipeline.
  • the slurry is heated to heat. After the slurry is thoroughly mixed in the mixer, it enters the oxygen delignification reaction tower.
  • the protective agent is magnesium sulfate, and the amount is 1.3% by weight of the absolute dry pulp.
  • the inlet temperature is 95 ° C
  • the pressure is 0.9 MPa
  • the residence time is 65 minutes.
  • the slurry was able to carry out a sufficient delignification reaction with a temperature of 103 ° C at the top of the column and a pressure of 0.35 MPa.
  • the slurry is sprayed into the slurry tank and diluted, and after washing, the unbleached pulp is obtained, and after washing, the unbleached pulp is obtained, and the unbleached pulp has a crack length of 6,600 meters.
  • the tearing degree is 270 mN
  • the whiteness is 403 ⁇ 4>ISO
  • the folding resistance is 65 times
  • the beating degree is 35 ° SR.
  • the above unbleached pulp was then bleached.
  • the bleaching is specifically as follows: the chlorine content of the C section is 3% of the absolute dry pulp, and the concentration of the pulp is 3
  • bleaching temperature is 40 ° C, bleaching time is 50 minutes; E section adding sodium hydroxide is 3% dry pulp, pulp concentration is 12%, bleaching temperature is 58 ° C, time is 100 Minutes; P-stage hydrogen peroxide is added in an amount of 4% of absolute dry pulp, pulp concentration is 10%, pulp pH is controlled at 11.5, chelating agent is added in an absolute dry pulp amount of 0.2%, and protective agent is magnesium sulfate. 0.4%, the bleaching temperature is 95 ° C, the bleaching time is 150 minutes, and the whiteness is 78% ISO, the crack length is 6,300 meters, the folding resistance is 60 times, and the tearing degree is 270 mN. .
  • the straw raw material was prepared according to the method of Example 1 and then charged into a ball type digester, and the cooking liquid was added to the ball type digester, and the amount of the dry raw material was 15% by the amount of alkali. 1 : 3, the amount of strontium added is 0.6% of the amount of dry raw materials.
  • the first heating was carried out to 120 ° C, and the temperature was kept at this temperature for 40 minutes, and the temperature was raised to 168 ° C by secondary heating, and the temperature was raised and kept for 150 minutes.
  • a high-hardness pulp with a hardness of 18 equivalent to the Kappa number of 27 is obtained, and the degree of beating is 18.4° SR, which is then sent to a conventional single-screw extruder for extracting black liquor for slurrying.
  • the slurry concentration before extrusion is 8%, the concentration of the slurry from the extruder is 22%, diluted with dilute black liquor to a concentration of 2.5%, sent to the sieve for coarse slurry screening, the sieve loss is 0.2%, and the concentration is high.
  • the loss was 0.1%, and the slurry obtained after the slag removal was washed into a horizontal belt washer, the slurry concentration during washing was 3.0%, and the concentration of the slurry from the washer was 9%.
  • the slurry is kept at 65-75 °C, and then transported to a high-frequency disintegrator for dissolving.
  • the slurry is heated to 65 ° C by a screw conveyor and transferred to a medium-concentration slurry tube.
  • the slurry is firstly subjected to quenching and tempering treatment to remove the air in the slurry to be fluidized, and then sent to the oxygen delignification reaction tower through a centrifugal medium-concentration pump.
  • the slurry in the pipeline before entering the reaction tower with the added oxygen of 35 kg per ton of pulp and the alkali content is 2% of the alkaline solution of sodium hydroxide, and steam is introduced into the pipeline.
  • the slurry is heated to heat.
  • the protective agent is magnesium sulfate, and the amount is 1% by weight of the absolute dry pulp.
  • the inlet temperature is 102 ° C
  • the pressure is 1.12 MPa
  • the residence time is 70 minutes.
  • the slurry was able to carry out a sufficient delignification reaction with a temperature of 104 ° C at the top of the column and a pressure of 0.5 MPa.
  • the slurry is sprayed into the slurry tank and diluted, and after washing, the unbleached pulp is obtained.
  • the unbleached pulp has a crack length of 6,100 m, a tearing degree of 255 mN, and a whiteness of 35 ⁇ 3 ⁇ 4 ISO.
  • the folding resistance is 40 times and the beating degree is 32° SR.
  • the above unbleached pulp was further bleached.
  • the bleaching is a traditional CEH three-stage bleaching, specifically: the chlorine content of the C section is 4% of the absolute dry pulp, the concentration of the pulp is 3.2%, the bleaching temperature is 45 ° C, and the bleaching time is 45 minutes; The amount of sodium hydroxide added to the E section is 3% of the absolute dry pulp, the concentration of the slurry is 12%, the bleaching temperature is 57 ° C, and the time is 120 minutes; the amount of the sodium segment of sodium hypochlorite is 2% of the absolute dry pulp amount.
  • the bleaching temperature is 30 ° C, and the bleaching time is 150 minutes, and a high quality grass pulp with a whiteness of 65% ISO, a crack length of 5,600 m, a folding resistance of 35 times, and a tearing degree of 235 mN can be obtained.
  • the Arundo donax was prepared according to the method described in Example 2, and the Arundo donax was prepared.
  • the hot black liquor at a temperature of 120 °C was charged into the cooking pot through a potter. When the pan was full, the lid was closed.
  • the cooking temperature is supplemented with 13CTC cooking agent, and the air in the pot is discharged and boosted to 0.45 MPa.
  • the cooking liquid heating circulation pump and the tube heater of the system are turned on to raise the cooking liquid to 152 ° C, and the temperature rise, heat preservation and replacement For 180 minutes, the slurry is finally sent to the spray pot by pumping; wherein the amount of sodium hydroxide used is 9% by weight of the dry raw material, and the amount of sodium sulfite is 4% by weight of the dry raw material.
  • the amount of hydrazine is 0.04% by weight of the dry raw material, and the liquid ratio is 1:10.
  • the high-hardness pulp is sent to the prior art to reduce the diameter of the single-screw extruder for the black liquor.
  • a high-concentration pulp with a concentration of 20% is obtained.
  • it is sent to a sieve for coarse slurry screening.
  • the sieve loss is 0.2%, and the impurities are removed by a high-concentration cleaner to lose 0.1%.
  • the slurry obtained after the slag is washed into a horizontal belt washer, and the slurry concentration during washing is 3.0%, the concentration of the pulp from the washer is 9%, and the washing process is maintained at 65-75 ° C, and is used after washing.
  • the high-frequency disintegrator was disintegrated, and then concentrated to 8%.
  • the slurry was heated to 80 ° C by a screw conveyor and transferred to a medium consistency slurry tube.
  • the slurry is firstly subjected to quenching and tempering treatment to remove the air in the slurry to be fluidized, and then sent to the oxygen delignification reaction tower through a centrifugal medium-concentration pump.
  • the slurry is mixed with the added oxygen of 40 kg per ton of pulp and the amount of alkali in the pipeline before the entering the reaction tower, and the amount of alkali is mixed with 4% alkali solution of sodium hydroxide, and steam is introduced into the pipeline.
  • the slurry is heated to heat. After the slurry is thoroughly mixed in the mixer, it enters the oxygen delignification reaction tower.
  • the protective agent is magnesium sulfate, and the amount added is 0.8% by weight of the absolute dry pulp, and the inlet temperature is 98 ° C.
  • the pressure was 1.2 MPa and the residence time was 85 minutes to allow the slurry to undergo a full delignification reaction.
  • the temperature at the top of the column was 101 ° C and the pressure was maintained at 0.35 MPa.
  • the slurry is sprayed into a slurry tank and diluted, and after washing, the unbleached pulp is obtained.
  • the unbleached pulp has a crack length of 6,400 meters, a tearing degree of 260 mN, a whiteness of 38 ⁇ 3 ⁇ 4 ISO, a folding endurance of 70 times, and a beating degree of 35° SR.
  • the above unbleached pulp is further bleached with hypochlorite, specifically: H-sodium hypochlorite is added in an amount of 2.5% of the dry pulp, the bleaching temperature is 32 ° C, and the bleaching time is 100 minutes, and white is obtained.
  • the quality is 55 % ISO, the crack length is 5500 meters, the folding resistance is 50 times, and the tearing degree is 275mN.
  • the wheat straw was prepared according to the method of Example 3, and the hot black liquor having a temperature of 140 ° C was charged into the cooking pot through a potter.
  • the lid was closed, and the cooking pot was replenished with a temperature of 16 CTC.
  • the air in the pot is discharged and boosted to 0.6 MPa.
  • the cooking liquid heating circulation pump and the tube heater of the system are turned on to raise the temperature of the cooking liquid to 165 ° C, and the temperature is raised, kept and replaced for 230 minutes, and finally the slurry is pumped.
  • the retort pot wherein the amount of sodium hydroxide is 17% by weight of the dry raw material, the amount of sodium sulfite is 8% by weight of the dry raw material, and the amount of hydrazine is the weight of the dry raw material. 0.08%, the liquid ratio is 1:6.
  • the hardness is 22% potassium permanganate, which is equivalent to the high hardness pulp of Kappa price 35.
  • the degree of beating is 12.2° SR, and then sent to the conventional single-screw extruder for extracting black liquor for extrusion.
  • the concentration before the pulp is 12%
  • the concentration of the slurry coming out from the extruder is 25%
  • diluted with dilute black liquor to the concentration of the slurry to 3.0% sent to the sieve for coarse slurry screening, and the sieve loss is 0.4%.
  • the impurities are removed by a high-concentration cleaner to lose 0.1%, and the slurry obtained after the slag is removed into a horizontal belt washer to wash with a black liquor having a temperature of 75 ° C and a portion of water, and the slurry concentration during washing.
  • the concentration of the pulp from the washer is 12%
  • the temperature during the washing process is about 70 ° C
  • the high-frequency disintegrator for dissolving, after dissolving, the concentration is adjusted to 15% and then passed through the spiral.
  • the conveyor heats the slurry to 70 ° C and delivers it to a medium consistency slurry tube.
  • the slurry is first tempered in the middle thick slurry tube to remove the air in the slurry to be fluidized, and then sent to the oxygen delignification reaction tower through a centrifugal medium-concentration pump.
  • the slurry is mixed with the added oxygen of 30 kg per ton of pulp and the alkali solution of 4% of the dry pulp by sodium hydroxide before entering the reaction tower, and steam is introduced into the pipeline.
  • the slurry is heated to heat. After the slurry is thoroughly mixed in the mixer, it enters the oxygen delignification reaction tower.
  • the protective agent is magnesium sulfate, and the amount is 0.5% by weight of the absolute dry pulp.
  • the inlet temperature is 95 ° C
  • the pressure is 0.9 Mpa
  • the residence time is 90 minutes.
  • the slurry was allowed to carry out a sufficient delignification reaction, the temperature at the top of the column was 10 rC, the pressure was maintained at 0.25 MPa, and the lignin removal rate during the oxygen delignification was 86%.
  • the slurry is sprayed into the slurry tank and diluted, and the hardness (potassium permanganate value) of the slurry is lowered to 14, which corresponds to a Kappa price of 19.5.
  • the diluted slurry is then pumped into a two-stage vacuum washer for washing.
  • the unbleached pulp has a crack length of 5,700 meters, a tearing degree of 250 mN, a whiteness of 32 ⁇ 3 ⁇ 4 ISO, a folding endurance of 85 times, and a beating degree of 35 ° SR.
  • the above-mentioned unbleached pulp is subjected to conventional CEH three-stage bleaching, specifically: the chlorine content in the C section is 5% of the absolute dry pulp, the concentration of the pulp is 3.5%, the bleaching temperature is 38 ° C, and the bleaching time is 50 minutes.
  • the amount of sodium hydroxide added to the E section is 2% of the absolute dry pulp, the concentration of the slurry is 10%, the bleaching temperature is 60 ° C, and the time is 150 minutes; the amount of the sodium segment of sodium hypochlorite is 2.5 ⁇ of the absolute dry pulp amount. 3 ⁇ 4, bleaching temperature is 32 ° C, bleaching time is 100 minutes, you can get white grass with a whiteness of 73 % ISO, a crack length of 5500 meters, and a folding resistance of 70 times.
  • Straw, wheat straw and reed with a mass ratio of 1:1:1 were prepared according to the methods of Example 2, Example 3 and Example 6, respectively, and then passed through a potter by a hot black liquor having a temperature of 130 °C. Put it in the cooking pot and close the lid when the pan is full. Add the cooking liquid with a temperature of 140 °C to the cooking pot, and simultaneously discharge the air in the pot and raise the pressure to 0.45 MPa. Turn on the cooking liquid heating circulation pump and the tube heater of the system to raise the temperature of the cooking liquid to 155 ° C.
  • the degree of vulcanization is 9%.
  • the black liquor is added to the steaming ball for dilution, and the pressure is maintained at 0.65 MPa for spraying.
  • the hardness of the pulp is 23 potassium permanganate and the degree of beating is 21.5 ° SR.
  • the residual alkali concentration in the black liquor is 12 g/l.
  • the yield of the prepared high hardness pulp was 58%. It is sent to the conventional single-screw extruder for extracting black liquor for slurrying.
  • the concentration of the slurry from the extruder is 35%, diluted with dilute black liquor to the concentration of the slurry to 3.0%, and sent to the jump. Screening for coarse slurry screening, the sieve loss is 0.2%, and the impurities are removed by a high concentration separator to lose 0.1%.
  • the slurry obtained after the slag removal is then washed into a horizontal belt washer for slurry concentration during washing. 3.0%, the concentration of the pulp coming out of the washer is 9%, and it is kept at 70 °C during the washing process, and then transported to the high-frequency disintegrator for dissolving, and the pulp is first tempered through the middle thick slurry tube.
  • the air in the slurry is treated to be fluidized, and then sent to the oxygen delignification reaction tower through a centrifugal medium-concentration pump.
  • the slurry is mixed with the added oxygen of 20 kg per ton of pulp and the alkali solution of 4% by weight of sodium hydroxide on the basis of sodium hydroxide before entering the reaction tower, and steam is introduced into the pipeline.
  • the slurry is heated to heat. After the slurry is thoroughly mixed in the mixer, it enters the oxygen delignification reaction tower.
  • the protective agent is magnesium sulfate, and the amount is 1.5% by weight of the dry pulp.
  • the inlet temperature is 92 ° C
  • the pressure is 1.0 MPa
  • the residence time is 90 minutes.
  • the slurry was allowed to carry out a sufficient delignification reaction, the temperature at the top of the column was 102 ° C, and the pressure was maintained at 0.3 MPa. After the treatment is completed, the slurry is sprayed into the slurry tank and diluted, and after washing, the unbleached pulp is obtained.
  • the unbleached pulp has a crack length of 5000 m, a tearing degree of 230 mN, and a whiteness of 433 ⁇ 4>ISO.
  • the folding resistance is 65 times and the beating degree is 35 ° SR.
  • the above-mentioned unbleached pulp is subjected to conventional CEH three-stage bleaching, specifically: the chlorine content of the C section is 5% of the absolute dry pulp, the concentration of the pulp is 3.5%, the bleaching temperature is 40 ° C, and the bleaching time is 50 minutes.
  • the amount of sodium hydroxide added to the E section is 2% of the absolute dry pulp, the concentration of the slurry is 10%, the bleaching temperature is 55 ° C, and the time is 150 minutes; the amount of the sodium segment of sodium hypochlorite is 2.5% of the dry pulp amount.
  • the bleaching temperature is 32 ° C, and the bleaching time is 100 minutes.
  • the whiteness is 74% ISO, the crack length is 4,500 meters, the folding resistance is 35 times, and the tearing degree is 220 mN.
  • the hot black liquor having a temperature of 120 ° C is charged into the cooking pot through a potter, and when the pan is full, the lid is closed, and the temperature is added to the cooking pot to be cooked at 16 CTC. At the same time, the air in the pot is discharged and boosted to 0.6 MPa.
  • the cooking liquid heating circulation pump and the tube heater of the system are turned on to raise the cooking liquid to 168 ° C, and the temperature is raised, kept and replaced for 250 minutes, and finally pumped.
  • the slurry is sent to the spraying pot; wherein the cooking agent has a base amount of sodium hydroxide of 13%, a liquid ratio of 1:10, and a degree of sulfurization of 5%; before spraying,
  • the black liquor was added to the steaming ball for dilution, and the pressure was maintained at 0.65 MPa for spraying.
  • the hardness of the pulp was 18 potassium permanganate equivalent to 28 kappa, and the residual alkali concentration in the black liquor was 12 g/l.
  • the yield of the prepared high hardness pulp was 58%.
  • the high-hardness pulp obtained after the cooking is first squeezed by a single-screw extruder, and the black liquor is extruded through the slurry, and the impurities in the black liquor are also discharged together with the black liquor, and then the obtained slurry is washed with pressure.
  • Machine washing, after washing, the high-hardness pulp is diluted, diluted to a concentration of 12%, and then sent to a high-frequency disintegrator for dissolving and then oxygen delignification, the oxygen addition amount is 4% of the absolute dry pulp amount
  • the amount of alkali is 3% of the dry pulp by sodium hydroxide, and 0.8% magnesium sulfate is added as a protective agent.
  • the unbleached pulp has a crack length of 5,600 meters, a tearing degree of 270 mN, a whiteness of 25 ⁇ 3 ⁇ 4 ISO, a folding endurance of 65 times, and a beating degree of 35 ° SR.
  • the above unbleached pulp is further bleached, and the chlorination-alkali treatment-hypochlorite bleaching is carried out under the following conditions: the chlorine content is 3% of the absolute dry pulp, the pulp concentration is 3.5%, and the bleaching temperature is 42°. C, the bleaching time is 45 minutes; the alkali treatment conditions are as follows: the alkali amount is 2% of the absolute dry pulp, the slurry concentration is 12%, the bleaching temperature is 55 ° C, and the time is 100 minutes.
  • Hypochlorite bleaching Sodium hypochlorite is added in an amount of 3% of the absolute dry pulp, the bleaching temperature is 35 ° C, and the bleaching time is 100 minutes. After the completion of the bleaching, a white chemical slurry having a whiteness of 45% ISO, a crack length of 5300 m, a folding endurance of 50 times, and a tearing degree of 245 mN was obtained.
  • Example 16 After the cotton stalk raw material method of the first embodiment was prepared, after the cotton stalk raw material was prepared, the raw material was charged into the cooking pot through a potter by using a hot black liquid having a temperature of 140 ° C. After closing the lid, add the 16CTC cooking agent to the cooking pot, and at the same time, discharge the air in the pot and raise the pressure to 0.6MPa. Turn on the system's cooking liquid heating circulation pump and the tube heater to raise the cooking liquid to 165 °C.
  • the amount of alkali is 17% of the dry raw material, and the liquid ratio is 1 : 6, the amount of ⁇ added is 0.5% of the amount of dry raw materials. .
  • the black liquor is added to the steaming ball for dilution, and the pressure is maintained at 0.75 MPa for spraying.
  • the hardness of the pulp is the potassium permanganate value of 18, which is equivalent to the Kappa price of 26, and the beating degree is 19.8° SR, cooking.
  • the pH value at the end point was 12, and the yield of the high hardness pulp was 60%.
  • the high-hardness pulp obtained after the cooking is first squeezed by a single-screw extruder, and the black liquor is extruded through the slurry, and the impurities in the black liquor are also discharged together with the black liquor, and then the obtained slurry is washed with pressure.
  • Machine washing, after washing, the high-hardness pulp is diluted, diluted to a concentration of 8%, and then sent to a disc grinding and dispersing machine for decontamination and bleaching, first oxygen delignification, the oxygen addition amount is per ton of dry
  • the amount of pulp is 20kg, the amount of alkali is 3% of the dry pulp by sodium hydroxide, and the 1.2% magnesium sulfate salt of the dry pulp is added as a protective agent.
  • the temperature of oxygen delignification is 90 ° C, and the temperature is 80 minutes.
  • the temperature at the top of the tower is 98 ° C and the pressure is maintained at 0.3 MPa.
  • the slurry is sprayed into the slurry tank and diluted, and after washing, the unbleached pulp is obtained.
  • the unbleached pulp has a crack length of 6,700 m, a tearing degree of 270 mN, and a whiteness of 44 ⁇ 3 ⁇ 4 ISO.
  • the folding resistance is 65 times and the beating degree is 36° SR.
  • the above unbleached pulp is bleached, chlorinated-alkali treated-hypochlorite bleached, and the conditions of bleaching are: using chlorine as absolute dry pulp
  • the alkali treatment conditions are: the amount of alkali is 4% of the absolute dry pulp by sodium hydroxide, the slurry 10% concentration, bleaching temperature 65 ° C, time 150 minutes; hypochlorite bleaching: sodium hypochlorite is added in 4% of dry pulp, bleaching temperature is 35 ° C, bleaching time is 150 minutes .
  • a bleaching chemical slurry having a whiteness of 80% ISO, a crack length of 6,500 m, a folding endurance of 45 times, and a tearing degree of 260 mN was obtained.
  • Example 17 After the raw material of wheat straw was prepared according to the method of Example 1, the raw material was passed through a potter at a temperature of 120 ° C. Put it into the cooking pot, close the lid when the pot is full, add the 13CTC cooking agent to the cooking pot, and discharge the air in the pot and boost it to 0.4MPa. Turn on the cooking liquid heating pump and tube of the system. The heater heats the cooking liquid to 147 ° C, heats up, heats and replaces it for 180 minutes, and finally sends the slurry to the spraying pot by pumping; in the cooking agent, the amount of alkali is determined by sodium hydroxide.
  • the dry material amount is 9%, and the liquid ratio is 1:9, and the amount of rhodium added is 0.8% of the amount of the dry raw material. .
  • the hardness of the wheat straw pulp is 20 potassium permanganate, and the degree of beating is 22° SR.
  • the wheat straw pulp is pumped to a screw extruder for slurrying, and the extruded black liquor is evaporated as a water reducing agent.
  • the concentration of the pulp increased from 8% before extrusion to 30%, at which time the pH of the pulp was 8, the concentration of the black liquor extruded was 11 'Be (20 ° C), and the concentration of residual alkali was 8 g/L.
  • the obtained slurry was diluted with a diluted black liquor at 75 ° C to a concentration of 2.5%, washed with a vacuum washer, and concentrated with 10%.
  • the wet weight of the washed pulp is 1.8g
  • the washing degree of the washing slurry is 350ppm, and it is transported to the high-frequency disintegrator for dissolving.
  • the degree of decomposing of the wheat straw pulp before the disintegration is 24° SR
  • the disintegration of the wheat straw pulp after the disintegration The degree is 26° SR
  • the temperature of the wheat straw pulp before the disintegration is 60 °C
  • the temperature of the wheat straw pulp after the disintegration is 65 °C.
  • the concentrated black liquor obtained from the degraded wheat straw pulp can be used for the subsequent evaporation as a water reducing agent, and the slurry is then subjected to quenching and tempering in the middle thick slurry tube to remove the air in the slurry to be fluidized, and then centrifuged.
  • the slurry pump is delivered to the oxygen delignification reaction column.
  • the slurry is mixed with the added oxygen of 20 kg per ton of pulp and the alkali solution of 4% by weight of sodium hydroxide on the basis of sodium hydroxide before entering the reaction tower, and steam is introduced into the pipeline.
  • the slurry is heated to heat. After the slurry is thoroughly mixed in the mixer, it enters the oxygen delignification reaction tower.
  • the protective agent is magnesium sulfate, and the amount is 1% by weight of the absolute dry pulp.
  • the inlet temperature is 95 ° C
  • the pressure is l.lMPa
  • the residence time is 75 minutes.
  • the slurry was allowed to carry out a sufficient delignification reaction, the temperature at the top of the column was 100 ° C, and the pressure was maintained at 0.6 MPa.
  • the slurry is sprayed into the slurry tank and diluted, and then washed to obtain the unbleached pulp.
  • the unbleached pulp has a crack length of 6,600 meters, a tearing degree of 230 mN, and a whiteness of 43 ⁇ 3 ⁇ 4ISO, with a folding resistance of 40 times and a beating degree of 35° SR.
  • the bleaching conditions are as follows: the chlorine content is 3% of the dry pulp, the pulp concentration is 3.5%, the bleaching temperature is 40 °C, bleaching The time is 45 minutes; the conditions of the alkali treatment are: the amount of alkali is 2% of absolute dry pulp, the concentration of pulp is 12%, the bleaching temperature is 55 ° C, and the time is 100 minutes; Hydrogen peroxide bleaching includes: Hydrogen peroxide is added in an amount of 4% of the dry pulp, the concentration of the pulp is 10%, the pH is 11, the amount of the chelating agent is 0.2% of the dry pulp, and the amount of the magnesium sulfate protecting agent is used.
  • the bleaching temperature was 97 ° C and the bleaching time was 130 minutes.
  • the bleached slurry was pumped into a vacuum washer for washing, and after bleaching, a bleaching chemical slurry having a whiteness of 78% ISO, a crack length of 6,500 m, a folding resistance of 35 times, and a tearing degree of 185 mN was obtained.
  • the straw was prepared according to the method of Example 2, and the raw material was charged into the cooking pot through a potter by a hot black liquor having a temperature of 120 ° C. When the pan was full, the lid was closed, and the temperature was added to the cooking pot.
  • the cooking agent is 13CTC, and the air in the pot is discharged and raised to 0.6 MPa.
  • the cooking liquid heating circulation pump and the tube heater of the system are turned on to raise the cooking liquid to 156 ° C, and the temperature is raised, kept and replaced for 180 minutes.
  • the amount of the ammonium sulfite is 9% of the amount of the dry raw material, and the amount of the sodium hydroxide is 8% of the dry raw material, and the liquid ratio is 1 : 6;
  • the hardness of the straw pulp is 18 potassium permanganate, which is equivalent to the Kappa price of 26
  • the degree of beating is 21 ° SR, and then dissipated by the disc disintegrator, after dissolving
  • the straw pulp has a beating degree of 27° SR.
  • the disintegrated straw pulp is then pumped to a screw extruder for "concentrated" black liquor treatment, and the resulting concentrated black liquor can be used for subsequent evaporation as a fertilizer, and the concentration of the extruded pulp is from the pre-slurry.
  • 10% increase to 24% the pH value of the pulp is 8, the concentration of black liquor is 9° Be (20 °C), the residual ammonium is 8g/L, and the straw pulp obtained after the slurry is black liquor.
  • Diluted to the concentration of the slurry to 2.5% sent to the sieve for coarse slurry screening, the sieve loss is 0.3%, and the impurities are removed by the high concentration cleaner, the loss is 0.2%, and the straw pulp obtained after the sieve is skipped.
  • the washing is carried out by a vacuum washer, and the washing process is maintained at 65-75 ° C, and then the slurry is adjusted to 10% and sent to a high-frequency disintegrating machine for dissolving, and the slurry is first passed through a medium-concentrating tube to be quenched and tempered.
  • the air in the slurry is fluidized and then sent to the oxygen delignification reaction column by a centrifugal medium-concentration pump.
  • the slurry is mixed with the added oxygen of 20 kg per ton of pulp and the alkali content of the alkali solution of 3.5% by weight of sodium hydroxide in the pipeline before entering the reaction tower, and steam is introduced into the pipeline.
  • the slurry is heated to heat.
  • the protective agent is magnesium sulfate, and the amount is 1% by weight of the absolute dry pulp.
  • the inlet temperature is 0 ° C
  • the pressure is 0.9 Mpa
  • the residence time is 85 minutes.
  • the slurry was able to carry out a sufficient delignification reaction with a temperature of 105 ° C at the top of the column and a pressure of 0.4 MPa.
  • the slurry is sprayed into a slurry tank and diluted, and after washing, the unbleached pulp is obtained.
  • the unbleached pulp has a crack length of 6,900 meters, a tearing degree of 235 mN, a whiteness of 42 ⁇ 3 ⁇ 4 ISO, a folding endurance of 45 times, and a beating degree of 38 ° SR.
  • the above unbleached pulp is finally bleached, and the chlorination-alkali treatment-hypochlorite bleaching is carried out under the following conditions: the chlorine content is 2.5% of the dry pulp, the concentration of the pulp is 3.5%, and the bleaching temperature is 43 °C.
  • the bleaching time is 50 minutes;
  • the alkali treatment condition is: the alkali amount is 4% of the absolute dry pulp, the slurry concentration is 10%, the bleaching temperature is 55 ° C, and the time is 120 minutes;
  • Hypochlorite bleaching sodium hypochlorite is added in an amount of 4% of the dry pulp, the bleaching temperature is 35 ° C, and the bleaching time is 150 minutes.
  • Example 19 After the straw was prepared according to the preparation method of Example 2, the straw raw material was charged into the cooking pot through a potter from a hot black liquor having a temperature of 140 ° C, and the lid was closed after cooking. The temperature in the pot is supplemented with 16 CTC cooking agent, and the air in the pot is discharged and boosted to 0.75 MPa.
  • the cooking liquid heating circulation pump and the tube heater of the system are turned on to raise the cooking liquid to 173 ° C, and the temperature rise, heat preservation and replacement are 220 minutes, the pump is finally sent to the spraying pot by the pump; wherein the amount of ammonium sulfite is 15% of the amount of the dry raw material, and the liquid ratio is 1:10; the rice straw is obtained after cooking.
  • the hardness is 16 potassium permanganate, equivalent to Kappa price 24, the beating degree is 10 ° SR, the straw pulp is adjusted to 10% with black liquor, and then pumped to a single screw extruder for "concentration" black.
  • the obtained concentrated black liquor can be used for subsequent evaporation as a water reducing agent, and the concentration of the extruded slurry is increased from 10% before the extrusion to 35%, and the pH of the slurry is 8, and extruded.
  • the concentration of black liquor is 9Be' (20 ° C)
  • the concentration of residual alkali is 8g / L
  • the slurry will be obtained.
  • the concentration is 6.1 ° Be 'thin black liquor to dilute the slurry concentration to 3.03 ⁇ 4>, and sent to the sieve for coarse slurry screening, the sieve loss is 0.3%, and the residue is removed by high concentration.
  • the impurities were removed, the loss was 0.2%, and the straw pulp was washed with a drum vacuum washer.
  • the temperature during the washing process was 65 °C, and the degree of beating of the coarse pulp entering the washer was 31.
  • ° SR the slurry is heated and sent to the medium thick slurry pipe for quenching and tempering treatment.
  • the medium concentration pump is sent to the oxygen delignification reaction tower for delignification treatment, and then washed again with oxygen delignification black liquor, and the washed pulp is washed.
  • the wet weight of the material was 1.8 g, and the residual liquid after washing was 440 ppm.
  • the concentration of the slurry after washing was 9%, and the unbleached pulp was obtained.
  • the unbleached pulp has a crack length of 7,200 meters, a tearing degree of 250 mN, a whiteness of 36 ⁇ 3 ⁇ 4 ISO, a folding endurance of 45 times, and a beating degree of 35 ° SR.
  • the above-mentioned unbleached pulp is sent to a bleaching process for chlorination-alkali treatment-hydrogen peroxide bleaching.
  • the conditions for bleaching are as follows: the chlorine content is 3% of the dry pulp, the pulp concentration is 3.5%, and the bleaching temperature is 45°. C, the bleaching time is 45 minutes; the alkali treatment conditions are as follows: the alkali amount is 2% of the absolute dry pulp, the slurry concentration is 12%, the bleaching temperature is 55 ° C, and the time is 100 minutes.
  • the amount of hydrogen peroxide added is 5% of the absolute dry pulp, the concentration of the pulp is 11%, the pH is 11, the amount of the chelating agent is 0.2% of the absolute dry pulp, and the amount of the magnesium sulfate protecting agent is the absolute dry pulp. 0.4%, the bleaching temperature was 98 ° C, and the bleaching time was 115 minutes.
  • a bleached chemical pulp having a whiteness of 65 ⁇ 3 ⁇ 4 ISO, a crack length of 6,800 m, a folding resistance of 30 times, and a tearing degree of 210 mN was obtained.
  • the straw prepared by the method of Example 3 was immersed in an immersion screw machine with an alkali solution containing 4% of the amount of dry straw in terms of sodium hydroxide in an immersion screw machine, and then sent to a steaming ball.
  • the amount of hydrazine added is 0.6% of the amount of dry raw material, the ratio of liquid to 1: 3, and the temperature is raised to 110 ° C by heating once, and the temperature is kept at this temperature for 50 minutes, and the temperature is 165 after the second heating.
  • the resulting concentrated black liquor can be used for the subsequent water reducing agent, the concentration of black liquor is 10 ° Be ' (20 ° C), residual alkali 10g / L, temperature 75 ° C, and then
  • the straw pulp obtained after the squeezing is diluted with black liquor to a concentration of 3.0%, sent to a sieve for coarse slurry screening, the sieve loss is 0.2%, and the impurities are removed by a high concentration slag remover, and the loss is 0.1%.
  • the straw pulp obtained after slag removal is transported to a disc disintegrator for dissolving.
  • the degree of beating of the straw pulp before the disintegration is 25 ° SR, and the degree of beating of the straw pulp after the disintegration is 28 ° SR, relative to before the disintegration
  • the temperature of the straw pulp after decontamination increases by about 5-1 CTC.
  • the slurried slurry was then heated by a screw conveyor to 80 ° C and transferred to a medium consistency slurry tube.
  • the slurry is first subjected to quenching and tempering treatment in the middle thick slurry pipe to remove the air in the slurry to be fluidized, and then sent to the oxygen delignification reaction tower through a centrifugal medium-concentration pump.
  • the slurry was mixed with 20 kg of oxygen per ton of slurry and 4% by weight of sodium hydroxide added to the slurry before entering the reaction column, and steam was heated in the line to heat the slurry. After the slurry is thoroughly mixed in the mixer, it enters the oxygen delignification reaction tower.
  • the protective agent is magnesium sulfate, and the amount is 1% by weight of the absolute dry pulp.
  • the inlet temperature is 95 ° C
  • the pressure is 1.0 MPa
  • the residence time is 75 minutes.
  • the slurry was allowed to carry out a sufficient delignification reaction, the temperature at the top of the column was 100 ° C, and the pressure was maintained at 0.4 MPa.
  • the slurry is sprayed into the slurry tank and diluted, and the hardness of the slurry is lowered to the potassium permanganate value 13, which is equivalent to the Kappa price of 17.6 and the degree of beating is 30°SR.
  • the diluted slurry was then pumped into a two-stage vacuum washer with a pump to obtain an unbleached slurry.
  • the unbleached pulp has a crack length of 5,600 meters, a tearing degree of 270 mN, a whiteness of 45 ⁇ 3 ⁇ 4 ISO, a folding endurance of 65 times, and a beating degree of 35 ° SR.
  • the traditional CEH three-stage bleaching is used later, specifically: the chlorine content of the C section is 3% of the absolute dry pulp, and the concentration of the pulp is 3.2%.
  • the bleaching temperature is 40 ° C, the bleaching time is 60 minutes; the amount of sodium hydroxide added in the E section is 2.5% of the absolute dry pulp, the concentration of the pulp is 12%, the bleaching temperature is 58 ° C, and the time is 120 minutes;
  • the amount of H-sodium hypochlorite added is 3% of the absolute dry pulp, the bleaching temperature is 30 ° C, the bleaching time is 120 minutes, the whiteness is 78 % ISO, the crack length is 5200 m, and the folding resistance is 45.
  • High quality straw pulp Comparative example
  • the quality index of the bleached chemical pulp prepared in the present invention is compared with the hardwood pulp and the common wheat straw pulp, and the results are as follows:

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Abstract

La présente invention concerne un procédé de production de pâte à partir d'herbes, qui comprend les étapes consistant à cuire la matière à base d'herbes pour produire une pâte de dureté élevée qui possède une dureté de valeur K de 16 à 28 et un degré de raffinage de 10 à 24°SR, à pousser et à laver la pâte de dureté élevée résultante pour produire la pâte lavée, et à désagréger la pâte lavée pour obtenir une pâte. La pâte obtenue est soumise à un traitement ultérieur pour produire une pâte chimique blanchie. La pâte chimique blanchie est fabriquée à partir de matière à base d'herbes et possède une longueur de rupture de 4 500 à 8 000 m, une résistance au pliage de 20 à 70 fois, une résistance à la déchirure de 180 à 280 mN, un degré de raffinage de 32 à 38°SR, et une brillance de 65 à 82 % ISO. La matière à base d'herbes est d'abord cuite pour produire une pâte de dureté élevée avec une dureté de valeur K de 16 à 28 lors du procédé de production de la pâte chimique blanchie. La pâte chimique blanchie est un type de pâte chimique blanchie à base d'herbes de haute qualité. Le procédé est un procédé économique et respectueux de l'environnement avec une consommation moindre de liqueur de cuisson et un temps de cuisson plus court.
PCT/CN2008/001378 2007-07-27 2008-07-25 Procédé de production de pâtes à papier à partir d'herbes et pâtes obtenues par le procédé Ceased WO2009015556A1 (fr)

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