CN101451319A - Low brightness pulp prepared by ammonium sulfite steam cooking straw raw material, preparation method thereof and use thereof - Google Patents
Low brightness pulp prepared by ammonium sulfite steam cooking straw raw material, preparation method thereof and use thereof Download PDFInfo
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- CN101451319A CN101451319A CNA2007103002047A CN200710300204A CN101451319A CN 101451319 A CN101451319 A CN 101451319A CN A2007103002047 A CNA2007103002047 A CN A2007103002047A CN 200710300204 A CN200710300204 A CN 200710300204A CN 101451319 A CN101451319 A CN 101451319A
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- 239000002994 raw material Substances 0.000 title claims abstract description 67
- PQUCIEFHOVEZAU-UHFFFAOYSA-N Diammonium sulfite Chemical compound [NH4+].[NH4+].[O-]S([O-])=O PQUCIEFHOVEZAU-UHFFFAOYSA-N 0.000 title claims abstract description 45
- 239000010902 straw Substances 0.000 title claims abstract description 43
- 238000002360 preparation method Methods 0.000 title claims abstract description 40
- 238000010411 cooking Methods 0.000 title abstract description 7
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 81
- 239000001301 oxygen Substances 0.000 claims abstract description 81
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 78
- 238000000034 method Methods 0.000 claims abstract description 76
- 239000003513 alkali Substances 0.000 claims abstract description 35
- 238000005660 chlorination reaction Methods 0.000 claims abstract description 16
- 229920001131 Pulp (paper) Polymers 0.000 claims abstract description 10
- 238000004519 manufacturing process Methods 0.000 claims abstract description 5
- 239000002002 slurry Substances 0.000 claims description 139
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 83
- 238000009835 boiling Methods 0.000 claims description 62
- 230000008569 process Effects 0.000 claims description 41
- 238000006243 chemical reaction Methods 0.000 claims description 40
- 238000010009 beating Methods 0.000 claims description 34
- 238000004061 bleaching Methods 0.000 claims description 26
- 239000000463 material Substances 0.000 claims description 17
- 238000009413 insulation Methods 0.000 claims description 16
- 238000010025 steaming Methods 0.000 claims description 11
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims description 10
- 230000000740 bleeding effect Effects 0.000 claims description 10
- 239000000460 chlorine Substances 0.000 claims description 10
- 229910052801 chlorine Inorganic materials 0.000 claims description 10
- 238000000465 moulding Methods 0.000 claims description 10
- 229920002472 Starch Polymers 0.000 claims description 6
- 235000019698 starch Nutrition 0.000 claims description 6
- 239000008107 starch Substances 0.000 claims description 5
- 150000002926 oxygen Chemical class 0.000 claims description 3
- 230000000274 adsorptive effect Effects 0.000 claims description 2
- 230000008676 import Effects 0.000 claims description 2
- 230000000474 nursing effect Effects 0.000 claims description 2
- 238000007645 offset printing Methods 0.000 claims description 2
- 230000001681 protective effect Effects 0.000 claims description 2
- 230000035484 reaction time Effects 0.000 claims description 2
- 238000003466 welding Methods 0.000 claims description 2
- 239000011121 hardwood Substances 0.000 abstract description 2
- 239000012286 potassium permanganate Substances 0.000 abstract 1
- 238000005406 washing Methods 0.000 description 32
- 239000000123 paper Substances 0.000 description 22
- 239000000835 fiber Substances 0.000 description 17
- 238000010790 dilution Methods 0.000 description 15
- 239000012895 dilution Substances 0.000 description 15
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical group [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 description 14
- 238000004537 pulping Methods 0.000 description 13
- 244000025254 Cannabis sativa Species 0.000 description 11
- 238000007598 dipping method Methods 0.000 description 10
- 229920005610 lignin Polymers 0.000 description 8
- 239000003223 protective agent Substances 0.000 description 8
- 239000000126 substance Substances 0.000 description 8
- 229910052943 magnesium sulfate Inorganic materials 0.000 description 7
- 235000019341 magnesium sulphate Nutrition 0.000 description 7
- 239000000047 product Substances 0.000 description 7
- 229920002488 Hemicellulose Polymers 0.000 description 6
- 238000005516 engineering process Methods 0.000 description 6
- 238000002156 mixing Methods 0.000 description 6
- 239000007844 bleaching agent Substances 0.000 description 5
- 238000005470 impregnation Methods 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- 210000002985 organ of corti Anatomy 0.000 description 5
- 238000009955 starching Methods 0.000 description 5
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 4
- 230000029087 digestion Effects 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000002803 maceration Methods 0.000 description 4
- 239000003607 modifier Substances 0.000 description 4
- 238000012545 processing Methods 0.000 description 4
- 230000001105 regulatory effect Effects 0.000 description 4
- 241000196324 Embryophyta Species 0.000 description 3
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- 239000001913 cellulose Substances 0.000 description 3
- 230000006378 damage Effects 0.000 description 3
- 238000006073 displacement reaction Methods 0.000 description 3
- 238000005243 fluidization Methods 0.000 description 3
- 239000012535 impurity Substances 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 210000001519 tissue Anatomy 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 2
- LSNNMFCWUKXFEE-UHFFFAOYSA-N Sulfurous acid Chemical compound OS(O)=O LSNNMFCWUKXFEE-UHFFFAOYSA-N 0.000 description 2
- 235000011941 Tilia x europaea Nutrition 0.000 description 2
- 229920002522 Wood fibre Polymers 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 2
- 238000006731 degradation reaction Methods 0.000 description 2
- 239000004571 lime Substances 0.000 description 2
- 230000014759 maintenance of location Effects 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- GEHJYWRUCIMESM-UHFFFAOYSA-L sodium sulfite Chemical compound [Na+].[Na+].[O-]S([O-])=O GEHJYWRUCIMESM-UHFFFAOYSA-L 0.000 description 2
- 239000002025 wood fiber Substances 0.000 description 2
- 241000609240 Ambelania acida Species 0.000 description 1
- 235000017166 Bambusa arundinacea Nutrition 0.000 description 1
- 235000017491 Bambusa tulda Nutrition 0.000 description 1
- 229920000742 Cotton Polymers 0.000 description 1
- 238000006424 Flood reaction Methods 0.000 description 1
- 241001349804 Juncus alpinoarticulatus Species 0.000 description 1
- 240000007594 Oryza sativa Species 0.000 description 1
- 235000007164 Oryza sativa Nutrition 0.000 description 1
- 235000014676 Phragmites communis Nutrition 0.000 description 1
- 244000082204 Phyllostachys viridis Species 0.000 description 1
- 235000015334 Phyllostachys viridis Nutrition 0.000 description 1
- 235000008331 Pinus X rigitaeda Nutrition 0.000 description 1
- 235000011613 Pinus brutia Nutrition 0.000 description 1
- 241000018646 Pinus brutia Species 0.000 description 1
- 240000006394 Sorghum bicolor Species 0.000 description 1
- 235000011684 Sorghum saccharatum Nutrition 0.000 description 1
- 241000209140 Triticum Species 0.000 description 1
- 235000021307 Triticum Nutrition 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
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- 239000010905 bagasse Substances 0.000 description 1
- 239000011425 bamboo Substances 0.000 description 1
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- 230000001351 cycling effect Effects 0.000 description 1
- 230000035613 defoliation Effects 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 210000002615 epidermis Anatomy 0.000 description 1
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- 239000012467 final product Substances 0.000 description 1
- 238000009432 framing Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- 239000002655 kraft paper Substances 0.000 description 1
- 159000000003 magnesium salts Chemical class 0.000 description 1
- 238000010297 mechanical methods and process Methods 0.000 description 1
- 239000005416 organic matter Substances 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- 229920001296 polysiloxane Polymers 0.000 description 1
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- 238000005086 pumping Methods 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 235000009566 rice Nutrition 0.000 description 1
- 238000012216 screening Methods 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 235000010265 sodium sulphite Nutrition 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 235000014347 soups Nutrition 0.000 description 1
- LSNNMFCWUKXFEE-UHFFFAOYSA-L sulfite Chemical compound [O-]S([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-L 0.000 description 1
- -1 tissue Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 238000003809 water extraction Methods 0.000 description 1
- 238000005200 wet scrubbing Methods 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
Abstract
The invention relates to low-whiteness pulp prepared by a straw raw material by an ammonium sulfite method and a preparation method thereof. The whiteness of the low-whiteness pulp is 50 to 60 percent ISO, the fracture length is between 4.5 and 7.2km, the tearability is between 200 and 300mN, and the folding times are between 30 and 121. The preparation method comprises the steps of ammonium sulfite cooking, oxygen delignification, chlorination and alkali treatment, wherein the ammonium sulfite cooking is to cook the raw material into high-hardness pulp the harness of which has a potassium permanganate value of between 16 and 28 and is equivalent to a Kappa number of between 24 and 50. The low-whiteness pulp has higher strength, particularly has the fracture length and the folding times which exceed the level of hardwood pulp, can be directly used for manufacturing newsprints, books, napkins and so on, or is applied to manufacturing other paper products more widely only by adding little wood pulp, greatly reduces the cost for products, and also ensures the strength of the products.
Description
Technical field
The present invention relates to a kind of low brightness pulp and preparation method thereof, particularly a kind of low brightness pulp, its preparation method and application thereof of straw raw material ammonium sulfite boiling preparation.
Background technology
At present, world's paper pulp raw material major part is a timber, and particularly developed countries such as the U.S., Canada, various countries, Northern Europe and Russia almost all use pulping wood.Along with the increase year by year of timber demand amount, timber price also rises steadily.The country that many timber resources are few needs a large amount of timber of introducing, even and the more rich country of timber resources as Canada, also estimates will occur soon the log situation that supply falls short of demand.Therefore, the raw material problem has become the significant problem of various countries' development pulp industry, and the source of pulping raw material is also in continuous expansion.
In the pulping and paper-making industry, utilizing the grass raw material to carry out slurrying is comparatively common a kind of pulping process in China.The grass kind plant pulping raw material mainly comprises straw, wheat straw, bagasse, Chinese alpine rush, reed, bamboo, straw, cotton stalk, sorghum stalk etc., " the non-wood-fiber soda pulping process application manual commonly used " that its pulping process commonly used can be write with reference to " non-wood-fiber soda pulping process application manual commonly used " and alkaline straw-pulp Professional Committee of China Paper Industry Technical Association.
The method of producing paper pulp with string has: chemical method, Mechanical Method, chemical mechanical pulping.Chemical pulping is by chemical action, make raw material disassociation pulping by some composition of removing in the plant fiber material, be a kind of most widely used pulping process, in the chemical method boiling, divide lime method, soda processes, anthraquinone-soda processes, sulfate process, sulfite cooking again.
As sulphite process of the prior art, its technical process is at first to get the raw materials ready, the raw material that will carry out pretreated production paper pulp pack into rotary spherical digester, upright pot and connect in the equipment such as (digester, vertical digester, continuous steamers) of steaming, add chemicalss such as ammonium sulfite again, feed Steam Heating toward rotary spherical digester, upright pot or in even steaming, slightly starched after insulation a period of time.
At present, most enterprises in pulp and paper industry be faced with all that paper making raw material is in short supply, energy shortage, environmental pollution, paper pulp straw pulp problem of low quality particularly.Along with China's accession to the WTO, the situation that paper industry faces is severe more, and the competition between the enterprise also is growing more intense.How to reduce production costs, reduce and pollute, improving the quality of products to satisfy with paper is the downstream industry of raw material, as industries such as printing, journalism, packing, cigarette, is the problem that the papermaker need consider.Based on above-mentioned factor, make how people's further research of having to reduces the cost of papermaking.
The making grass pulp technology is a system engineering, to study the overall process of slurrying according to the inhomogeneity of the biological structure of grass fiber raw material and the particularity of chemical composition, fibers in grass class slurrying has following characteristics: 1. heavily get the raw materials ready, silica removal, remove heteroproteose cell, improve pulp quality and drainability, reduce the discharging of black liquor; 2. the characteristic of grass fiber delignification.Owing in the grass fiber the easy molten lignin of more alkali is arranged, its slurrying difficulty is reduced, but it requires higher delignification rate that fiber is dissociated again simultaneously, so its pulping process should be very different with timber.3. owing to silicone content height in the raw material, the carbohydrate content height causes its black liquor viscosity height, and recovery difficult is big.4. contain a large amount of heteroproteose cells in the fibers in grass class, papermaking is formed a series of harm.5. the bleachability of straw pulp is good than timber, easily adopts short flow process to bleach.
Straw is the fibrous raw material that China generally uses.With timber relatively, the cellulose of straw and lignin content are all less, hemicellulose level is more, the institutional framework pine is dredged, alkali lye soaks people's raw material inside easily, swallow boils that alkali charge is less, temperature is lower, the time is shorter, paper pulp yield is lower, the slurrying ratio is easier to.Available soda processes, sulfate process, neutrality and alkaline sodium sulfite legal system get natural color pulp and bleached pulp.The also available lime method of straw is produced the crude pulp of using for straw board, but pulp quality is not good in bisulfites method and acid industry kraft cooking.
The article of " the straw ammonium sulfite is optimized cooking schedule " has been delivered and be entitled as to 2003 the 4th phases of Heilungkiang papermaking, and this article discloses the optimal conditions of straw ammonium sulfite boiling, but the prepared pulp quality of the method for this boiling is not high.
In addition, the range of application that whiteness is lower than the made paper product of the low brightness pulp of 70%ISO is more and more wider, as newsprint, books, napkin paper etc., but can't reach direct applied requirement by the low brightness pulp intensity that straw raw material makes, need to add other slurries that make by timber, thereby improved cost.
Summary of the invention
Therefore, the object of the present invention is to provide a kind of low brightness pulp of straw raw material ammonium sulfite boiling preparation, this slurry intensity is good, has higher fracture length, tearability and folding number.
In order to realize purpose of the present invention, a kind of low brightness pulp of straw raw material ammonium sulfite boiling preparation is provided, the whiteness of described low brightness pulp is 50-60%ISO, fracture length is 4.5-7.2km, tearability is 200-300mN, and folding number is 30-121 times, and beating degree is 32-38 ° of SR; The fracture length of preferred described low brightness pulp is 5.0-7.2km, and tearability is 220-274mN, and folding number is 50-121 times, and beating degree is 32-36 ° of SR; More preferably the fracture length of described low brightness pulp is 5.5-7.2km, and tearability is 240-274mN, and folding number is 70-121 times.
Another object of the present invention is to provide a kind of preparation method of above-mentioned low brightness pulp, comprise ammonium sulfite boiling, oxygen delignification, chlorination and alkali treatment, described ammonium sulfite boiling is that the straw raw material boiling is become hardness is permanganate number 16-28, is equivalent to the high-hardness pulp of card uncle valency 24-50; Described high-hardness pulp preferred hardness is equivalent to card uncle valency 29-48 for permanganate number 18-27; Described high-hardness pulp most preferably hardness is equivalent to card uncle valency 34-42 for permanganate number 20-25.
Traditional technology is often boiled the hardness of slurry very low, causes declining to a great extent of pulp strength, and the present invention obtains the higher slurry of hardness by boiling, carries out follow-up treatment step again, has guaranteed the intensity of the low brightness pulp that obtains.
Ammonium sulfite boiling of the present invention comprises the steps:
1) add steaming preparation in straw raw material, wherein the consumption of ammonium sulfite is an over dry material quantity 9-13%, and liquor ratio is 1:2-4;
2) feed steam and heat, little steam bleeding is carried out in heat temperature raising insulation 20-40 minutes when temperature is 120-140 ℃, continues heat temperature raising to 165-173 ℃, is incubated 60-90 minutes.
Digestion process is the committed step of slurrying, because institutional framework, microstructure, chemical composition and the lignin molecular structure etc. of timber and grass as raw material are all variant, therefore, the delignification reaction course also has very big difference in digestion process.Generally contain more hemicellulose and less lignin in the straw raw material, and hemicellulose is present in mainly in the cell membrane, this just helps the process of boiling delignification.In the method for the present invention, the chemical steaming soup has been carried out strict control, its concentration has been reduced, reduced degraded and damage the required composition of slurrying such as cellulose, hemicellulose.Simultaneously, reduce temperature retention time as far as possible, the time that makes straw raw material be in high temperature shortens, thereby has reduced the cellulose in the raw material and the degraded of hemicellulose.Therefore, protect the required composition of slurrying in the grass kind plant raw material in the method for the present invention to greatest extent, shortened temperature retention time greatly simultaneously, reduced energy consumption.
The preferred oxygen delignification of the present invention comprises:
1) concentration of the high-hardness pulp of gained is 8-18% after the adjusting boiling;
2) this stock pump is delivered to the oxygen delignification reaction tower, and feed NaOH and oxygen; And
3) this slurry carries out delignification reaction in this oxygen delignification reaction tower, and obtaining hardness is permanganate number 10-14, is equivalent to the slurry of card uncle valency 13-19.8.
Wherein, the hardness of the slurry that more preferably obtains after the oxygen delignification in the step 3) is permanganate number 14.5-17.7.
The hardness that the present invention starches after to oxygen delignification is controlled, and is in order to guarantee that lignin is sloughed as much as possible on the one hand, has guaranteed the intensity of the slurry that obtains in addition on the one hand again.Equally, the method for oxygen delignification can adopt any method of prior art, and the hardness that only needs control to handle the back slurry gets final product in the framework of the present definition.
The concentration that the present invention regulates high-hardness pulp is meant that the concentration adjustment with described high-hardness pulp is 8-18%, that is to say in carry out oxygen delignification under the dense condition.In the major advantage of dense oxygen delignification be: invest less; Since in the success of dense mixing and pumping technology, the processing of slurry is dense more much easier than high; Slurry concentration is lower, and the corrosion of equipment is few, also the danger of not burning in oxygen.
Oxygen delignification of the present invention is the single hop oxygen delignification, carries out in the oxygen delignification reaction tower.In the oxygen delignification process, described slurry is 95-100 ℃ in the temperature of this reaction tower import department, and pressure is 0.9-1.2MPa, and the temperature in exit is 100-105 ℃, and pressure is 0.2-0.6MPa.In the described oxygen delignification alkali charge in NaOH to 2-4% of oven dry stock amount, the addition of oxygen is 20-40kg slurry per ton; The reaction time of described slurry in this reaction tower is 75-90 minutes.Adopting the single hop oxygen delignification mainly is the intensity that guarantees paper pulp for further, relative multistage oxygen delignification, and the carrying out of single hop oxygen delignification is less to cellulosic degradation.The technological parameter of single hop oxygen delignification of the present invention generally speaking temperature is lower, comparatively speaking the time longer, mainly be for the gentle more delignification reaction that carries out, avoid cellulosic degraded as far as possible.
The delignification rate is 86-98% in the oxygen delignification process of the present invention.
The present invention will adopt conveying worm that the high rigidity slurry is heated to 70-80 ℃ before described oxygen delignification and be transported to underflow pipe in again, and in this, in the underflow pipe slurry is carried out modifier treatment and get rid of the interior air of slurry, be delivered to the oxygen delignification reaction tower through centrifugal middle underflow pump.
Add magnesium salts in the oxygen delignification process of the present invention as protective agent, consumption is an oven dry stock amount 0.2-1%.
Chlorination of the present invention chlorine dosage be oven dry stock 2.5-3%, the concentration of slurry is 3-3.5%, temperature is to carry out 45-60 minutes under 50-55 ℃ the condition.
Alkali treatment of the present invention alkali charge in NaOH be 10-12% to the concentration of oven dry stock amount 2-4%, slurry, temperature is to carry out 100-150 minutes under 50-55 ℃ the condition.
The present invention also comprises the process that raw material is flooded before boiling, described being immersed in the dipping spiral organ carried out.The mode that said impregnation process adopts is: maceration extract is flooded raw material, make liquor ratio reach 1:2-4, in insulation and mixing more than 10 minutes in the spiral macerator more than 85 ℃, wherein insulation mixes 10-40 minutes for well between 85-95 ℃ under normal pressure.Maceration extract is fully contacted with raw material, make the dipping of raw material evenly complete.Described maceration extract can be certain density aqueous slkali, in 4% the aqueous slkali of NaOH to the over dry material quantity, also can be the mixed liquor of alkali and black liquor as alkali charge, and the concentration of used black liquor is 11-14 ° of Be ' (20 ℃).
Raw material has been carried out the dipping preliminary treatment, utilized black liquor as waste material, make black liquor obtain cycling and reutilization, reduced the pressure that environment is handled black liquor, because to the preliminary treatment of raw material dipping, make that heteroproteose cell, hemicellulose, the lignin deviate from are that main black liquid separation is discharged when heat treated, for next step digestion process is prepared.
The present invention also can be before flooding raw material, can adopt prior art that raw material is carried out preliminary treatment, promptly adopt conventional dried, wet feed preparation, to remove impurity such as defoliation, fringe, grain, marrow, can alleviate the pressure of subsequent technique like this, and improve the quality of rice straw pulp.Dried, wet feed preparation can adopt existing conventional equipment, as chaffcutter, screening machine, dust removal machine, wet scrubbing Straw-crumbling machine, inclined screw Water Extraction Machinery etc.Raw material through the removal moisture after getting the raw materials ready also can be fine fodder, and deduction moisture is the over dry grass, and the length of general blade is at 15-30mm, and the technology of getting the raw materials ready of raw material is technology as well known to those skilled in the art.
The present invention is preferably after boiling, carry out shove to the slurry after the boiling before the oxygen delignification.Can be 8-15% high-hardness pulp with gained concentration after the boiling enters from the inlet of press master, carries out shove, and after the extruding black liquor, concentration is that 20-30% slurry is discharged from the outlet of press master.The beating degree of this high-hardness pulp before carrying out shove is 22-28 ° of SR, and the beating degree after the shove is 23-29 ° of SR.The black liquor of being extruded Baume degrees in the time of 20 ℃ is 7-9 ° of Be ', and the concentration of the ammonium sulfite of the remnants in the black liquor is 8-10g/L.The slurry that comes out from the outlet of press master dilutes with the black liquor that pulp washing the subsequent technique displaces, and described black liquor is 3-6 ° of Be ' at 20 ℃ of Baume degrees, and the concentration that makes slurry is 2.5-3% to deliver to jump and screen.
Press master described in the present invention is single-screw or the Double screw pulp extruder that is used for extracting black liquor in the prior art.When using press master to carry out shove, because the process at shove can produce very big extruding force, temperature rises rapidly, impel fiber separation, divide silk, brooming, conquassation, primary wall is destroyed, the enough energy of fiber absorbs make fibrous inside produce very big stress, and the reactivity worth of high-hardness pulp is greatly improved.Simultaneously, fiber produces fibrillating, and impurity is dissolved in the black digestion liquid between epidermis organic matter and fiber, discharges by liquid outlet groove, and fiber fineness is greatly improved.Some ash contents in the black liquor and impurity are also along with black liquor is discharged from, for sufficient preparation has been carried out in next step pulp washing and bleaching.Preferred described press master is the acroll press washer of reducing.Utilize the Reducing screw press master, make slurry in the space that slowly diminishes, make the about dehydration of compressed slurry layer consistent.The acroll press washer that the present invention is selected, after high-hardness pulp is carried out shove, the beating degree of described high-hardness pulp changes little, that is to say, described high-hardness pulp is through after the press master shove, can the fibre length that fiber is intrinsic keep relatively goodly, reduce the damage of fiber to greatest extent.
The press master that adopts among the present invention also can be two rod press masters, can realize the effect that the present invention will reach equally.And water consumption can reduce greatly.
Can also after boiling, discongest slurry before the oxygen delignification in the method for the present invention, can adopt the existing equipment of discongesting, as mill fluffer in deflaker, kneading machine, dry pan, the beating equipment and defibrator etc., because they can play the effect of discongesting fiber and reducing cut staple as far as possible.In the process of discongesting, fiber naturally separately is easy to wherein lignin is come out, and makes follow-up delignification handle to become and is more prone to better effects if.This is discongested and can carry out immediately after boiling, also can carry out before oxygen delignification, can also carry out behind shove.In fact, between any processing step between boiling and the oxygen delignification, can carry out this and discongest, can both reach the effect that needs.
Low brightness pulp of the present invention is meant resulting slurry after material cooking, oxygen delignification, chlorination and the alkali treatment.
In addition, low brightness pulp of the present invention can be used for preparing newsprint, supercalendered paper, wrapping paper, paper diaper, crepe toilet paper, tissue, face tissue, napkin paper, tissue, paper for kitchen, writing paper, offset paper, offset printing paper, single face writing paper, M.G.offset paper and corrugated paper.
Also can be used for preparing moulded paper pulp product, described goods comprise: bowl, basin, cup, bucket, dish, dish, pallet and cutlery box; Carriage, electric welding protective cover, Indoor decorative plate, molding flowerpot, molding seedling-raising cup, molding slippers and adsorptive pads toilet seat cushion; Molding medical tray container, molding medical nursing product and disposable medical vessel.
Beneficial effect of the present invention is: low brightness pulp intensity of the present invention is higher, especially fracture length and folding number have surpassed the level of hardwood pulp, can be directly used in the paper of framing news, books, napkin paper etc., perhaps only need add wood pulp seldom and be applied to make other paper products widely, significantly reduce the cost of product, guarantee the intensity of product simultaneously again.Method of the present invention is by the hardness of the slurry that obtains of control boiling, carry out oxygen delignification then, both made that lignin is wherein effectively removed, reduced degradation of fiber again as far as possible, delignification rate 86-98% in its oxygen delignification process, thus can access the good low brightness pulp of intensity.
The specific embodiment
Embodiment 1
To flood through the straw of the back 30mm that gets the raw materials ready, adopt the dipping spiral organ, maceration extract is that alkalinity is in 4% the aqueous slkali of NaOH to the over dry material quantity, liquor ratio 1:4,85 ℃ of insulations mixed after 40 minutes under normal pressure, and the raw material behind the dipping is delivered in the rotary spherical digester.Add steaming preparation in rotary spherical digester, the consumption of ammonium sulfite is an over dry material quantity 11%, and liquor ratio is 1:3; Feed steam in the rotary spherical digester and heat, insulation is 40 minutes during heat temperature raising to 125 ℃, carries out little steam bleeding, continues heat temperature raising to 170 ℃, is incubated 75 minutes.
Obtaining hardness after the boiling is permanganate number 18, is equivalent to the high-hardness pulp of card uncle valency 27.Then the slurry after the boiling is carried out shove.Can be 15% high-hardness pulp with gained concentration after the boiling enters from the inlet of two rod press masters, carries out shove, and after the extruding black liquor, concentration is that 30% slurry is discharged from the outlet of press master.The beating degree of this high-hardness pulp before carrying out shove is 28 ° of SR, and the beating degree after the shove is 29 ° of SR.The Baume degrees of the black liquor that shove is extruded is 7 ° of Be ' at 20 ℃, and the concentration of the ammonium sulfite of the remnants in the black liquor is 8g/L.
The slurry that comes out from the outlet of press master dilutes with 60 ℃ warm water, and the concentration that makes slurry is 2.5% to deliver to jump and screen, and carries out pulp washing according to the method for routine then, regulates the concentration to 10% of starching behind the pulp washing.Next adopt deflaker to discongest in resulting slurry.Heat this slurry to 70 ℃ by conveying worm then and be transported in the underflow pipe.This slurry makes it fluidization at the air that middle underflow Guan Zhongxian gets rid of in the slurry through modifier treatment, after centrifugal middle underflow pump is transported to the oxygen delignification reaction tower.This slurry before entering reaction tower in pipeline with the oxygen of the 20kg slurry per ton that adds and alkalinity for mixing in 4% the aqueous slkali of NaOH to the oven dry stock amount, and feeding steam should be starched heat temperature raising in pipeline.This slurry enters the oxygen delignification reaction tower after fully mixed in blender afterwards; protective agent is a magnesium sulfate; addition is 1% of an oven dry stock weight; 95 ℃ of inlet temperatures; pressure 0.9Mpa stops and made this slurry can carry out sufficient delignification reaction in 75 minutes, and tower top temperature is 100 ℃; pressure remains 0.5MPa, and the delignification rate is 86% in the oxygen delignification process.After finishing dealing with this slurry is spurted stock tank and dilution, this moment, the hardness of slurry was reduced to permanganate number 10, was equivalent to card uncle valency 13.With pump the stock pump of dilution is gone into two sections vacuum pulp washing machine washings afterwards, carry out chlorination and alkali treatment again, chlorine dosage is 3% of an oven dry stock during chlorination, and the concentration of slurry is 3.2%, and the temperature of bleaching is 55 ℃, and the time of bleaching is 45 minutes; Alkali charge is to 2.5% of oven dry stock amount in NaOH during alkali treatment, the concentration of slurry is 12%, bleaching temperature is 50 ℃, time is 120 minutes, can obtain a kind of low brightness pulp of straw raw material ammonium sulfite boiling preparation, and whiteness is 55%ISO, fracture length is 5.2km, tearability is 240mN, and folding number is 85 times, and beating degree is 36 ° of SR.
Embodiment 2
To be that the straw of 15-20mm carries out boiling through length behind the conventional dry raw material preparation: add steaming preparation in rotary spherical digester, wherein the consumption of ammonium sulfite be an over dry material quantity 9%, and liquor ratio is 1:4; Feed steam again and heat in rotary spherical digester, little steam bleeding is carried out in heat temperature raising insulation 20 minutes when temperature is 130 ℃, continues heat temperature raising to 165 ℃, is incubated 90 minutes.Obtaining hardness after the boiling is permanganate number 24, is equivalent to the high-hardness pulp of card uncle valency 39.Then the high-hardness pulp after the boiling is carried out shove, being 10% high-hardness pulp with gained concentration after the boiling enters from the inlet of reducing single-screw press master, carries out shove, and after the extruding black liquor, concentration is that 25% slurry is discharged from the outlet of press master.The beating degree of this high-hardness pulp before carrying out shove is 24 ° of SR, and the beating degree after the shove is 25 ° of SR.The Baume degrees of the black liquor that shove is extruded is 8 ° of Be ' at 20 ℃, and the concentration of the ammonium sulfite of the remnants in the black liquor is 9g/L.
The slurry that comes out from the outlet of press master dilutes with the black liquor that pulp washing the subsequent technique displaces, and described black liquor is 6 ° of Be ' at 20 ℃ of Baume degrees, make slurry dense deliver to jump to 3% screen, carry out then regulating the concentration to 12% of starching behind the pulp washing.
Slurry carries out deflaker before oxygen delignification discongests, and after discongesting this slurry is heated to 70 ℃ and be transported to the oxygen delignification reaction tower by the positive displacement middle underflow pump.This slurry before entering reaction tower in pipeline with the oxygen of the 40kg slurry per ton that adds and alkalinity for mixing in 2% the aqueous slkali of NaOH to the oven dry stock amount, and feeding steam should be starched heat temperature raising in pipeline.This slurry enters the oxygen delignification reaction tower after fully mixed in blender afterwards, 100 ℃ of inlet temperatures, pressure 1.2Mpa, stopping in 90 minutes makes this slurry can carry out sufficient delignification reaction, tower top temperature is 105 ℃, pressure remains 0.2MPa, and the delignification rate is 90% in the oxygen delignification process.After finishing dealing with this slurry is spurted stock tank and dilution, this moment, the hardness (permanganate number) of slurry was reduced to 14, was equivalent to card uncle valency 19, and beating degree is 28 ° of SR.With pump the stock pump of dilution is gone into two sections vacuum pulp washing machine washings afterwards, can obtain a kind of brown stock of straw raw material ammonium sulfite boiling preparation, chlorine dosage is 5% of an oven dry stock during chlorination, and the concentration of slurry is 3%, the temperature of bleaching is 52 ℃, and the time of bleaching is 60 minutes; The amount that adds NaOH during alkali treatment is an oven dry stock amount 2%, the concentration of slurry is 12%, bleaching temperature is 55 ℃, and the time is 100 minutes, can obtain a kind of low brightness pulp of straw raw material ammonium sulfite boiling preparation, it is characterized in that, the whiteness of described low brightness pulp is 50%ISO, and fracture length is 7.2km, and tearability is 200mN, folding number is 60 times, and beating degree is 35 ° of SR.
Embodiment 3
To be that the straw of 20-25mm is put into rotary spherical digester and carried out boiling through the length after conventional the getting the raw materials ready, in rotary spherical digester, add steaming preparation, the consumption of ammonium sulfite is to 10% of over dry material quantity, liquor ratio is 1:2, feed steam and heat, heat temperature raising is incubated 30 minutes when temperature is 120 ℃, carried out little steam bleeding 25 minutes, continue heat temperature raising to 173 ℃, be incubated 60 minutes.Obtaining hardness after the boiling is permanganate number 25, the high-hardness pulp that is equivalent to card uncle valency 43, then described high-hardness pulp is carried out shove, being about to gained concentration after the boiling and being 8% high-hardness pulp enters from the inlet of reducing Double screw pulp extruder, carry out shove, after the extruding black liquor, concentration is that 20% slurry is discharged from the outlet of press master.The beating degree of this high-hardness pulp before carrying out shove is 22 ° of SR, and the beating degree after the shove is 23 ° of SR.The Baume degrees of the black liquor that shove is extruded is 9 ° of Be ' at 20 ℃, and the concentration of the ammonium sulfite of the remnants in the black liquor is 10g/L.
The slurry that comes out from the outlet of press master dilutes with the black liquor that pulp washing the subsequent technique displaces, described black liquor is 4 ° of Be ' at 20 ℃ of Baume degrees, make slurry dense deliver to jump to 2.8% screen, method is routinely carried out pulp washing then, regulates the concentration to 18% of starching afterwards.
Before oxygen delignification, adopt dry pan to discongest, heat this slurry to 80 ℃ then and be transported to the slurry tower slurry.The air that this slurry is got rid of in the slurry through modifier treatment earlier in the slurry tower makes it fluidization, after centrifugal middle underflow pump is transported to the oxygen delignification reaction tower, advance the oxygen that adds 20kg slurry per ton before the tower and alkalinity in 3.5% the aqueous slkali of NaOH, and in pipeline, feed steam and should starch heat temperature raising the oven dry stock amount.This slurry enters the oxygen delignification reaction tower after fully mixed in blender afterwards; protective agent is a magnesium sulfate, and addition is 1% of an oven dry stock weight, 90 ℃ of inlet temperatures; pressure 1.2Mpa; stopped 85 minutes, tower top temperature is 105 ℃, and pressure remains 0.4MPa; the delignification rate is 98% in the oxygen delignification process; this slurry is spurted stock tank and dilution, and this moment, the hardness K (permanganate number) of slurry was reduced to 14, was equivalent to card uncle valency 19.With pump the stock pump of dilution is gone into two sections vacuum pulp washing machine washings afterwards, carry out chlorination and alkali treatment again, chlorine dosage is 4% of an oven dry stock during chlorination, and the concentration of slurry is 3%, and the temperature of bleaching is 55 ℃, and the time of bleaching is 50 minutes; Alkali charge is to oven dry stock amount 2% in NaOH during alkali treatment, the concentration of slurry is 12%, bleaching temperature is 52 ℃, time is 100 minutes, can obtain a kind of low brightness pulp of straw raw material ammonium sulfite boiling preparation, and whiteness is 52%ISO, fracture length is 6.5km, tearability is 230mN, and folding number is 110 times, and beating degree is 32 ° of SR.
Embodiment 4
To put into the spiral macerator through the straw of 20mm behind the conventional dry raw material preparation, add alkali charge again for 4% aqueous slkali of over dry material quantity being carried out impregnation process in NaOH, liquor ratio 1:3,85 ℃ of insulations mixed 30 minutes under normal pressure.Afterwards, will send in the boiling vessel through the raw material of impregnation process, and add steaming preparation, wherein the addition of ammonium sulfite is 11% of an over dry material quantity, and liquor ratio is 1:3; Feed steam again and heat, heat temperature raising carries out little steam bleeding to temperature is 130 ℃ time insulation 40 minutes, continues heat temperature raising to 170 ℃, is incubated 80 minutes.
Obtaining hardness after the boiling is permanganate number 20, is equivalent to the high-hardness pulp of card uncle valency 31, then the slurry after the boiling is carried out shove.Being 12% high-hardness pulp with gained concentration after the boiling enters from the inlet of the single-screw press master of reducing, carries out shove, and after the extruding black liquor, concentration is that 26% slurry is discharged from the outlet of press master.The beating degree of this high-hardness pulp before carrying out shove is 25 ° of SR, and the beating degree after the shove is 26 ° of SR.The Baume degrees of the black liquor that shove is extruded is 9 ° of Be ' at 20 ℃.Residual ammonium sulfite is 12g/L in the black liquor.The slurry that comes out from the outlet of press master dilutes with the black liquor that pulp washing the subsequent technique displaces, described black liquor is 5 ° of Be ' at 20 ℃ of Baume degrees, the concentration to 3% of slurry is delivered to jump and screened, carry out pulp washing according to the method for routine then, and regulate the concentration to 15% of starching.
Heat this slurry to 80 ℃ by conveying worm then and be transported in the underflow pipe.This slurry makes it fluidization at the air that middle underflow Guan Zhongxian gets rid of in the slurry through modifier treatment, after centrifugal middle underflow pump is transported to the oxygen delignification reaction tower, advance the oxygen that adds 20kg slurry per ton before the tower and alkalinity in 4% the aqueous slkali of NaOH, and in pipeline, feed steam and should starch heat temperature raising the oven dry stock amount.This slurry enters the oxygen delignification reaction tower after fully mixed in blender afterwards; protective agent is a magnesium sulfate, and addition is 0.5% of an oven dry stock weight, 100 ℃ of inlet temperatures; pressure 0.9Mpa; stopped 90 minutes, tower top temperature is 104 ℃, and pressure remains 0.4MPa; the delignification rate is 92% in the oxygen delignification process; this slurry is spurted stock tank and dilution, and this moment, the hardness (permanganate number) of slurry was reduced to 10, was equivalent to card uncle valency 12.With pump the stock pump of dilution is gone into two sections vacuum pulp washing machine washings afterwards, bleach, chlorine dosage is 5% of an oven dry stock amount during chlorination, and the concentration of slurry is 3.2%, and the temperature of bleaching is 50 ℃, and the time of bleaching is 60 minutes; Alkali charge is an oven dry stock amount 2.5% during alkali treatment, the concentration of slurry is 10%, bleaching temperature is 55 ℃, time is 120 minutes, can obtain a kind of low brightness pulp of straw raw material ammonium sulfite boiling preparation, and the whiteness of described low brightness pulp is 58%ISO, fracture length is 6.8km, tearability is 280mN, and folding number is 121 times, and beating degree is 34 ° of SR.
Embodiment 5
To be that the straw of 15-20mm is put into the dipping spiral organ through length behind the conventional dry raw material preparation, add alkali charge in 3% the dipping solution of NaOH to the over dry material quantity, liquor ratio 1:4,95 ℃ of insulations mixed 40 minutes under normal pressure, after the black liquor discharge, in steamer, add steaming preparation, wherein the consumption of ammonium sulfite is with 12% of over dry material quantity, liquor ratio is 1:4, feed steam and heat, heat temperature raising is incubated 30 minutes when temperature is 125 ℃, carry out little steam bleeding, continue heat temperature raising to 168 ℃, be incubated 75 minutes.
Obtaining hardness after the boiling is permanganate number 22, is equivalent to the high-hardness pulp of card uncle valency 34.Being 13% high-hardness pulp with gained concentration after the boiling enters from the inlet of the Var-nip press of reducing varying pitch, carries out shove, and after the extruding black liquor, concentration is that 28% slurry is discharged from the outlet of press master.The beating degree of this high-hardness pulp before carrying out shove is 24 ° of SR, and the beating degree after the shove is 25 ° of SR, and the Baume degrees of the black liquor that shove is extruded is 11 ° of Be ' at 20 ℃, and residual ammonium sulfite is 13g/L in the black liquor.To regulate concentration to 2.5% through the slurry of shove, and deliver to jump and screen, and use three sections vacuum pulp washing machines to carry out pulp washing then, regulate the concentration to 14% of slurry behind the pulp washing.
Before oxygen delignification, slurry is discongested, adopt the mill fluffer in the beating equipment, heat this slurry to 70 ℃ and be transported to the oxygen delignification reaction tower through the positive displacement middle underflow pump.This slurry before entering reaction tower in pipeline with the oxygen of the 30kg slurry per ton that adds and alkalinity for mixing in 3% the aqueous slkali of NaOH to the oven dry stock amount, and feeding steam should be starched heat temperature raising in pipeline.This slurry enters the oxygen delignification reaction tower after fully mixed in blender afterwards; protective agent is a magnesium sulfate; addition is 0.5% of an oven dry stock amount; 98 ℃ of inlet temperatures; pressure 1.0Mpa stops in 80 minutes and makes this slurry can carry out sufficient delignification reaction, and tower top temperature is 102 ℃; pressure remains 0.4MPa, and the delignification rate is 88% in the oxygen delignification process.After finishing dealing with this slurry being spurted stock tank also dilutes, this moment, the hardness (permanganate number) of slurry was reduced to 13, be equivalent to card uncle valency 18, with pump the stock pump of dilution is gone into two sections vacuum pulp washing machine washings afterwards, bleach, chlorine dosage is 4% of an oven dry stock during chlorination again, and the concentration of slurry is 3.5%, the temperature of bleaching is 50 ℃, and the time of bleaching is 50 minutes; Alkali charge is to oven dry stock amount 3% in NaOH during alkali treatment, the concentration of slurry is 10%, bleaching temperature is 52 ℃, time is 150 minutes, can obtain a kind of low brightness pulp of straw raw material ammonium sulfite boiling preparation, and whiteness is 60%ISO, fracture length is 5.8km, tearability is 270mN, and folding number is 90 times, and beating degree is 33 ° of SR.
Embodiment 6
To be that the straw of 25-30mm is put into the dipping spiral organ through length behind the conventional dry raw material preparation, add alkali charge in NaOH to 3.5% the aqueous slkali of over dry material quantity and the mixed liquor of black liquor, the concentration of used black liquor is 14 ° of Be ' (20 ℃), liquor ratio 1:2,85 ℃ of insulations mixed 40 minutes under normal pressure.After impregnation process is intact raw material is delivered in the vertical digester, the consumption of ammonium sulfite is to over dry material quantity 13%, and liquor ratio is 1:2.5; Feed steam in the digester and heat, heat temperature raising insulation 40 minutes when temperature is 140 ℃ was carried out little steam bleeding after 30 minutes, continued heat temperature raising to 173 ℃, was incubated 90 minutes.
Obtaining hardness after the boiling is permanganate number 16, the high-hardness pulp that is equivalent to card uncle valency 24 is 14% high-hardness pulp again with the concentration of boiling gained to be entered from the inlet of two rod press masters, carries out shove, after the extruding black liquor, concentration is that 28% slurry is discharged from the outlet of press master.The beating degree of this high-hardness pulp before carrying out shove is 26 ° of SR, and the beating degree after the shove is 27 ° of SR.The Baume degrees of the black liquor that shove is extruded is 10 ° of Be ' at 20 ℃, and the ammonium sulfite that participates in the black liquor is 9g/L.The slurry that comes out from the outlet of press master dilutes with 60 ℃ warm water, and the concentration that makes slurry is to deliver to jump in 3% o'clock to screen, and washs with conventional method then.Regulating slurry afterwards dense is 25%, heats this slurry to 80 ℃ and is transported to slurry by conveying worm and manage chute and be transported to the oxygen delignification reaction tower by single rotor formula high density stock pump.Add the oxygen of 20kg slurry per ton and alkalinity in the reaction tower for mixing in 4% the aqueous slkali of NaOH to the oven dry stock amount; and feeding steam should be starched heat temperature raising in pipeline; this slurry enters this oxygen delignification reaction tower after fully mixed in blender afterwards; protective agent is a magnesium sulfate, and addition is 0.8% of an oven dry stock weight, 95 ℃ of inlet temperatures; pressure 1.0Mpa; stopped 80 minutes, tower top temperature is 105 ℃, and pressure remains 0.4MPa.The delignification rate is 91% in the oxygen delignification process, this slurry is spurted stock tank and dilution, this moment, the hardness (permanganate number) of slurry was reduced to 14, be equivalent to card uncle valency 19, with pump the stock pump of dilution is gone into two sections vacuum pulp washing machine washings afterwards, chlorine dosage is 3% of an oven dry stock during chlorination, and the concentration of slurry is 3.5%, the temperature of bleaching is 52 ℃, and the time of bleaching is 45 minutes; The amount that adds NaOH during alkali treatment is an oven dry stock amount 3%, the concentration of slurry is 11%, bleaching temperature is 50 ℃, time is 150 minutes, can obtain a kind of low brightness pulp of straw raw material ammonium sulfite boiling preparation, and whiteness is 58%ISO, fracture length is 4.5km, tearability is 300mN, and folding number is 50 times, and beating degree is 36 ° of SR.
Embodiment 7
To be that the straw of 20-40mm floods through length behind the conventional dry raw material preparation, put into the dipping spiral organ, add alkali charge in NaOH to 4% the aqueous slkali of over dry material quantity and the mixed liquor of black liquor, the concentration of used black liquor is 14 ° of Be ' (20 ℃), liquor ratio 1:2,85 ℃ of insulations mixed 25 minutes under normal pressure.After impregnation process is intact raw material is delivered in the vertical digester, the consumption of ammonium sulfite is to over dry material quantity 11%, and liquor ratio is 1:2.8; Feed steam in the digester and heat, heat temperature raising insulation 40 minutes when temperature is 134 ℃ was carried out little steam bleeding after 25 minutes, continued heat temperature raising to 170 ℃, was incubated 60 minutes.
Obtaining hardness after the boiling is permanganate number 23, the high-hardness pulp that is equivalent to card uncle valency 34 is 12% high-hardness pulp with gained concentration after the boiling to be entered from the inlet of reducing single-screw press master, carries out shove, after the extruding black liquor, concentration is that 24% slurry is discharged from the outlet of press master.The beating degree of this high-hardness pulp before carrying out shove is 24 ° of SR, and the beating degree after the shove is 25 ° of SR.Directly dilute with rare black liquor then, the concentration that makes slurry is 2.5% to deliver to jump and screen, and carries out pulp washing then, and regulating the concentration of starching is 20%.
Before oxygen delignification, slurry is discongested, adopts defibrator, heat this slurry to 70 ℃ and through the gear type high density stock pump be transported to the oxygen delignification reaction tower and in pipeline feeding steam should starch heat temperature raising.Add the oxygen of 30kg slurry per ton and alkalinity in the reaction tower in 4% the aqueous slkali of NaOH to the oven dry stock amount; protective agent is a magnesium sulfate; addition is 0.5% of an oven dry stock weight; 100 ℃ of inlet temperatures; pressure 1.1Mpa stops in 90 minutes and makes this slurry can carry out sufficient delignification reaction, and tower top temperature is 105 ℃; pressure remains 0.5MPa, and the delignification rate is 94% in the oxygen delignification process.After finishing dealing with this slurry is spurted stock tank and dilution, this moment, the hardness (permanganate number) of slurry was reduced to 13, was equivalent to card uncle valency 17.With pump the stock pump of dilution is gone into two sections vacuum pulp washing machine washings afterwards, bleach processing again: chlorine dosage is 3% of an oven dry stock during chlorination, and the concentration of slurry is 3%, and the temperature of bleaching is 52 ℃, and the time of bleaching is 50 minutes; Alkali charge is to oven dry stock amount 3% in NaOH during alkali treatment, the concentration of slurry is 12%, bleaching temperature is 50 ℃, time is 150 minutes, can obtain a kind of low brightness pulp of straw raw material ammonium sulfite boiling preparation, and whiteness is 50%ISO, fracture length is 5.0km, tearability is 240mN, and folding number is 30 times, and beating degree is 37 ° of SR.
Embodiment 8
To be that the straw of 30-35mm is put into rotary spherical digester and carried out boiling through length behind the conventional dry raw material preparation, and add steaming preparation, wherein the consumption of ammonium sulfite be to over dry material quantity 9%, and liquor ratio is 1:2; Feed steam again and heat, insulation is 20 minutes during heat temperature raising to 120 ℃, carries out little steam bleeding 20 minutes, continues heat temperature raising to 165 ℃, is incubated 60 minutes.
Obtaining hardness after the boiling is permanganate number 28, is equivalent to the high-hardness pulp of card uncle valency 50, then the slurry after the boiling is carried out shove.Being 11% high-hardness pulp with gained concentration after the boiling enters from the inlet of the single-screw press master of reducing, carries out shove, and after the extruding black liquor, concentration is that 22% slurry is discharged from the outlet of press master.The beating degree of this high-hardness pulp before carrying out shove is 27 ° of SR, and the beating degree after the shove is 28 ° of SR.The slurry that comes out from the outlet of press master dilutes with the black liquor that pulp washing the subsequent technique displaces, make slurry dense deliver to jump to 3% screen, pulp washing then, regulating slurry dense is 23%, then heats this slurry to 80 ℃ and is transported to the oxygen delignification reaction tower through the positive displacement high density stock pump.Add the oxygen of 30kg slurry per ton in the reaction tower and in 3.5% the aqueous slkali of NaOH, and in pipeline, feed steam and should starch heat temperature raising the oven dry stock amount.Protective agent is a magnesium sulfate, and addition is 0.8% of an oven dry stock weight, 100 ℃ of inlet temperatures; pressure 0.9Mpa stops in 75 minutes and makes this slurry can carry out sufficient delignification reaction, and tower top temperature is 108 ℃; pressure remains 0.6MPa, and the delignification rate is 86% in the oxygen delignification process.After finishing dealing with this slurry is spurted stock tank and dilution, this moment, the hardness (permanganate number) of slurry was reduced to 14, was equivalent to card uncle valency 19.5.With pump the stock pump of dilution is gone into two sections vacuum pulp washing machine washings afterwards.Bleach processing again, chlorine dosage is 4% of an oven dry stock during chlorination, and the concentration of slurry is 3.2%, and the temperature of bleaching is 50 ℃, and the time of bleaching is 55 minutes; Alkali charge is to oven dry stock amount 3% in NaOH during alkali treatment, the concentration of slurry is 12%, bleaching temperature is 52 ℃, time is 120 minutes, can obtain a kind of low brightness pulp of straw raw material ammonium sulfite boiling preparation, and whiteness is 60%ISO, fracture length is 4.5km, tearability is 200mN, and folding number is 40 times, and beating degree is 38 ° of SR.
Above embodiment is used to explain the present invention, and unrestricted the present invention.Simple change as the method for oxygen delignification, the method for boiling etc. all should belong to protection scope of the present invention.
Claims (15)
1. the low brightness pulp of a straw raw material ammonium sulfite boiling preparation is characterized in that the whiteness of described low brightness pulp is 50-60%ISO, fracture length is 4.5-7.2km, tearability is 200-300mN, and folding number is 30-121 times, and beating degree is 32-38 ° of SR.
2. low brightness pulp as claimed in claim 1 is characterized in that, the fracture length of described low brightness pulp is 5.0-7.2km, and tearability is 220-274mN, and folding number is 50-121 times, and beating degree is 32-36 ° of SR.
3. low brightness pulp as claimed in claim 1 is characterized in that, the fracture length of described low brightness pulp is 5.5-7.2km, and tearability is 240-274mN, and folding number is 70-121 times.
4. the method for a manufacturing such as each described low brightness pulp of claim 1-3, comprise ammonium sulfite boiling, oxygen delignification, chlorination and alkali treatment, it is characterized in that it is the high-hardness pulp of permanganate number 16-28 that described ammonium sulfite boiling becomes hardness with the straw raw material boiling.
5. method as claimed in claim 4 is characterized in that, also is included in the preceding process that raw material is flooded of boiling.
6. as claim 4 or 5 described methods, it is characterized in that described ammonium sulfite boiling comprises the steps:
1) add steaming preparation in straw raw material, wherein the consumption of ammonium sulfite is the ammonium sulfite solution to over dry material quantity 9-13%, and wherein liquor ratio is 1:2-4;
2) feed steam and heat, little steam bleeding is carried out in heat temperature raising insulation 20-40 minutes when temperature is 120-140 ℃, continues heat temperature raising to 165-173 ℃, is incubated 60-90 minutes.
7. method as claimed in claim 4 is characterized in that, described oxygen delignification comprises:
1) elder generation is 8-18% with the concentration adjustment of high-hardness pulp;
2) this stock pump is delivered to the oxygen delignification reaction tower, and add NaOH and oxygen; And
3) this slurry carries out the oxygen delignification reaction in this oxygen delignification reaction tower, obtains the slurry that hardness is permanganate number 10-14.
8. method as claimed in claim 7 is characterized in that, the starch degree after the oxygen delignification that obtains in the step 3) is a permanganate number 11-13.
9. method as claimed in claim 7 is characterized in that, described oxygen delignification is the single hop oxygen delignification, carries out in the oxygen delignification reaction tower; Described slurry is 95-100 ℃ in the temperature of this reaction tower import department, and pressure is 0.9-1.2MPa, and the temperature in exit is 100-105 ℃, and pressure is 0.2-0.6MPa.
10. method as claimed in claim 7 is characterized in that, alkali charge is that the addition of oxygen is 20-40kg slurry per ton in the 2-4% of NaOH to the oven dry stock amount in the described oxygen delignification; The reaction time of described slurry in this reaction tower is 75-90 minutes.
11., it is characterized in that the delignification rate is 86-98% in the described oxygen delignification process as any described method of claim 7-10.
12. method as claimed in claim 4 is characterized in that, described chlorination chlorine dosage be oven dry stock 2.5-3%, the concentration of slurry is 3-3.5%, temperature is to carry out 45-60 minutes under 50-55 ℃ the condition.
13. method as claimed in claim 4 is characterized in that, described alkali treatment alkali charge in NaOH to oven dry stock amount 2-4%, the concentration of slurry is 10-12%, bleaching temperature is to carry out 100-150 minutes under 50-55 ℃ the condition.
14. each described low brightness pulp of claim 1-3 is in preparation newsprint, supercalendered paper, wrapping paper, paper diaper, crepe toilet paper, tissue, face tissue, napkin paper, tissue, the application in paper for kitchen, writing paper, offset paper, offset printing paper, single face writing paper, M.G.offset paper and the corrugated paper.
15. the application of each described low brightness pulp of claim 1-3 in the preparation moulded paper pulp product, described goods comprise: bowl, basin, cup, bucket, dish, dish, pallet and cutlery box; Carriage, electric welding protective cover, Indoor decorative plate, molding flowerpot, molding seedling-raising cup, molding slippers and adsorptive pads toilet seat cushion; Molding medical tray container, molding medical nursing product and disposable medical vessel.
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|---|---|
| CN101451319B (en) | 2012-10-31 |
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