CN102352572B - Preparation method for bamboo wood dissolving pulp - Google Patents
Preparation method for bamboo wood dissolving pulp Download PDFInfo
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Abstract
The invention belongs to the technical field of bamboo wood dissolving pulp, and particularly relates to a preparation method for the bamboo wood dissolving pulp, which comprises the following preparation steps: (a) preparing a material; (b) cooking; (c) screening; (d) washing; (e) bleaching; and (f) manufacturing paper with the pulp. By adopting the preparation method for the bamboo wood dissolving pulp, the production efficiency and the product quality can be improved, simultaneously, the energy consumption, the chemical consumption and the pollution load are reduced, and the prepared bamboo wood dissolving pulp has high quality and high quality.
Description
Technical field
The invention belongs to preparation bamboo wood dissolving pulp technical field, relate in particular to a kind of preparation method of bamboo wood dissolving pulp.
Background technology
Dissolving pulp belongs to highly purified refined stock, is mainly used in to produce weaving viscose, nitrocellulose, acetate fiber, glassine paper, carboxymethyl cellulose or the like fiber derivative product, and dissolving pulp has purposes widely, and market demand is bigger.
China abounds with bamboo, bamboo wide in variety, distribute extensively, more rich bamboo resource is arranged, particularly in south, most of area all has plants bamboo in large area, wherein abundant and concentrated with the bamboo resource in Sichuan, Hunan, Guangxi, Yunnan, Chongqing, has than the large economy exploitation to be worth.Bamboo wood dissolving pulp also has unique function because of it contains bamboo fiber except that having cotton, chemistry that wooden dissolving pulp is similar or identical, physical property; The fiber product made from bamboo wood dissolving pulp, have air permeability and good, moment water imbibition, stronger ABRASION RESISTANCE and good characteristics such as dyeability, have again simultaneously natural antibacterial, antibacterial, remove mite, deodorization and anti-ultraviolet function, these are that other fiber product does not possess function, be subjected to textile industry and consumers in general's favor, therefore, bamboo wood dissolving pulp has very high exploitation value.
The preparation method of existing bamboo wood dissolving pulp is relative with equipment level backward, problem such as have that production efficiency is low, the heat energy utilization rate is not high, unstable product quality, environmental protection are difficult up to standard.Existing bamboo dissolved pulp preparation method, technology is relative with equipment level backward, exists production efficiency low, and the heat energy utilization rate is not high, unstable product quality, problem such as pollutional load is big.Imbody is as follows:
The deficiency that the boiling aspect exists: adopt traditional batch or transverse tube continuously cooking mode, digestion process herb liquid circulation with sheet stock to contact uniformity good inadequately, the cooking liquor alkali concn from high to low in the cooking reaction, the stripping lignin content from low to high, final stage of cooking, lignin stripping difficulty is in the process of Extended Delignification, effect is bad, and is bigger to cellulosic damage.Product quality there is considerable influence, and the deficiency that exists of the relatively low washing of heat energy utilization rate, screening aspect: adopt traditional pulp washing flow process, the washing device flow process is longer, needs 4 and above washing device before bleaching usually, and detersive efficiency is relatively low.In the screening heavy seeds such as the grains of sand in the sheet stock are handled inadequately, product quality is had certain influence.The closure of washing and screening is relatively poor, and the foul smell in the factory is obvious, and production environment is abominable relatively.
The deficiency that the bleaching aspect exists: it is main adopting C-E-H tradition tri-stage bleaching, and the contaminated wastewater load that bleaching process produces is big, and has internationally recognized carcinogen dioxin to produce.ECF bleaching after the improvement, oxygen delignification adopts one-part form, to going deep into delignification, protects cellulosic effect not enough.Usually also needing in addition increases acid treatment after bleaching is finished, just can reach the product quality requirement.
Therefore, need badly a kind of preparation method who overcomes the bamboo wood dissolving pulp of above-mentioned shortcoming is provided.
Summary of the invention
The objective of the invention is at the deficiencies in the prior art, and provide a kind of preparation method of bamboo wood dissolving pulp, mainly solved the problem that boiling and two operations of bleaching exist, can improve production efficiency and product quality, reduce energy resource consumption, chemical cost and pollutional load simultaneously, the bamboo wood dissolving pulp output height, the quality that make are good.
The present invention is achieved through technology.
A kind of preparation method of bamboo wood dissolving pulp, it comprises following preparation process: (a) get the raw materials ready, (b) boiling, (c) screening, (d) washing, (e) bleaching, (f) manufacture paper with pulp;
Described step (b) boiling may further comprise the steps:
(b1) steam dress pot; (b2) Steam Heating prehydrolysis; (b3) white liquid neutralization; (b4) hot black liquor displacement; (b5) temperature control heating and boiling make slurry; (b6) washing black liquid displacement, washing and cooling slurry; (b7) low temperature discharging;
Described step (c) screening may further comprise the steps: (c1) adopt one section desander, one section knotter and one section to wash the joint machine equipment and carry out scalping; (c2) adopt three sections pressurized screens, two sections desanders and one section vibrating screen equipment carry out fine screen;
Described step (d) washing is specially: dilution and screening slurry enter then and slightly wash and starch the system of washing and wash;
Described step (e) bleaching may further comprise the steps: (e1) oxygen delignification; (e2) ClO 2 bleaching under the strong acid condition; (e3) hydrogen peroxide and the extracting of oxygen boosting alkali; (e4) ClO 2 bleaching.
Described step (a) is got the raw materials ready and is specially:
Bamboo wood is adopted drum slicer, and cutting growth 13mm～50mm, the sheet stock of thickness 3mm～7mm, sheet stock make it to sift out bamboo bits and underproof sheet stock, sheet stock qualification rate 〉=85% through double-deck classifying screen classification.Underproof sheet stock screens after the desintegrator cutting once more.Through screening qualified sheet stock,, send into the sheet stock stockyard after washing and the dehydration and deposit stand-by by the sheet rag tub.Bamboo wood is based on cizu, bambusa textile, sinocalamus latiflorus.
Described step (b) boiling specifically may further comprise the steps:
(b1) steam dress pot: bamboo material is made sheet stock, be delivered to digester, feed low-pressure steam toward digester when carrying sheet stock; (b2) Steam Heating prehydrolysis: after steam dress pot is finished, use Steam Heating, make sheet stock prehydrolysis; (b3) white liquid neutralization: use in the white liquid in the white liquid bath of heat and sheet stock and steam condensate (SC) in the digester; (b4) hot black liquor displacement: with in the hot black liquor displacement cooking pot in the hot black liquor groove and waste liquid; (b5) temperature control is heated and boiling, makes the slurry of bamboo wood dissolving pulp; (b6) washing black liquid displacement, washing and cooling slurry; (b7) low temperature discharging.
Wherein, in the prehydrolysis of described step (b2) Steam Heating,, with the middle pressure steam heating, make the temperature in the digester reach 170 ℃～175 ℃ then earlier with the low-pressure steam heating; The pressure limit of low-pressure steam is 0.4Mpa～0.6Mpa, and the pressure limit of middle pressure steam is 0.9Mpa～1.3Mpa; Hydrolysis is by the control of P factor, and the scope of P factor is 500～600; The scope of the total time of Steam Heating prehydrolysis is 110 minutes～130 minutes.
Wherein, the white liquid neutralization of described step (b3) is with Na
2The O meter, the concentration 〉=90g/l of white liquid; The sulphidity of white liquid is 20%～30%.
Wherein, the displacement of described (b4) hot black liquor is specially: before temperature control white liquid is joined hot black liquor, then hot black liquor is pumped into the pump entry of digester, be pumped into the top and the bottom of digester by circulating pump, carry out two-way replacement, in in the displacement cooking pot and waste liquid, in being replaced and the double-edged fine-toothed comb of waste liquid by the middle part of digester cement out.
In in the temperature control hot black liquor displacement cooking pot of hot black liquor feeder and waste liquid.In order to have required alkali charge between locomorphic stage, before temperature control, white liquid is joined hot black liquor at black liquor.
Hot black liquor is pumped into the digester pump entry.Hot black liquor is assigned to digester top and bottom in outlet of circulating pump.In the bottom of digester, bend pipe inlet and conical entrance use simultaneously, so that cooking liquor can be diffused into the entire cross section of digester.Come out by digester middle part double-edged fine-toothed comb with waste liquid in being replaced.Two-way replacement that Here it is.Compare with traditional up-flow displacement, two-way replacement can be used sizable flow and not damage metathesis in displacement.
Step (b4) afterwards, temperature be below 100 ℃ in and waste liquid send into the washing black liquid groove, as washing black liquid, standby; Temperature be more than 100 ℃ in and waste liquid send into warm black liquor feeder, standby.In more than 100 ℃ and a waste liquid part warm liquid that is used for next pot boiling charge, in remaining and waste liquid pumping evaporation.Get back to the hot black liquor feeder with waste liquid in the heat.
Wherein, described step (b5) is specially: heating adds middle pressure steam in the circulatory system by steam distributor, and in whole heating and digestion process, cooking liquor is extracted out from the double-edged fine-toothed comb at the middle part of digester, send the top and the bottom of digester then back to, continuously circulation.
Stewing temperature is 170 ℃～180 ℃; The H factor of boiling is 300 ~ 400; The time of temperature control heating and boiling is 30 minutes ~ 50 minutes; With active alkali Na
2The O meter, alkali charge≤22%.
Heating directly adds middle pressure steam by steam distributor to be finished to the circulatory system, need not heat exchanger, therefore only needs small amount of steam, has also avoided the cleaning and the maintenance of heat exchanger simultaneously.At whole heating and digester cycle, black liquor cements out from the double-edged fine-toothed comb at digester middle part, sends the top and the bottom of digester then back to.In heating process, in order to calculate mean temperature in the digester, 1 temperature survey is arranged before the black liquor pump, by 2 temperature surveys, divide to be located at top and bottom loop pipeline behind the black liquor pump.The setting of temperature meter is in order to calculate the mean temperature in the digester, to reach temperature controlled purpose.
In the boiling stage, keep required boiling temperature and pressure in the digester, up to the H factor that reaches target.
Wherein, described step (b6) is specially: top and bottom from washing black liquid groove pumping washing black liquid to digester, and the black liquor of being replaced comes out from the double-edged fine-toothed comb at the middle part of digester; Magma is washed and cool off by replacement process, make the temperature of magma be lower than 100 ℃.
In the boiling ending phase, boiling is also being carried out, just by from washing black liquid groove pumping black liquor to digester, the displacement of beginning washing black liquid.The cooking liquor of heat is displaced to the hot black liquor feeder, so just stops cooking reaction.The hot black liquor that the black liquor of hot black liquor feeder is used for digester cycle afterwards adds displacement, and the black liquor that surpasses required washing black liquid displacement is sent to warm black liquor feeder.The washing black liquid displacement also is a two-way replacement technology.Continuous displacement by washing black liquid reaches required dilution factor.Last pulping temperature is lower than 100 ℃.The washing black liquid displacement also is first section washing of slurry.
Wherein, the discharging of described step (b7) low temperature is in particular: discharging is a pumping blow bin under low pressure.In the discharge process, in the digester bottom, slurry is washed the black liquor dilution.Dilution can mainly be to enter the mouth and the conical entrance dilution mouth of pipe to digester bottom, bend pipe by the boiling circulating pump.Backwash digester middle part double-edged fine-toothed comb also can diluted slurry.By slurry being washed the dilution cooling, to satisfy the requirement of slurrying line slurry quality temperature.Such discharge method has prevented distributing of foul gas effectively when reclaiming heat energy.
Described step (c) screening:
Wherein, described step (c1) adopts one section desander, one section knotter and one section to wash the joint machine equipment to carry out scalping and be specially:
(c11), the mashing pump after step (b) processing is delivered to knotter;
(c12), in knotter, the slurry of handling by the sieve aperture scalping enters subsequent processing, and the slag slurry by sieve aperture does not enter the joint machine of washing;
(c13), in washing the joint machine, after the knot in the slag slurry dries from the top spiral of washing the joint machine, drain between waste residue reclaims, and the slurry that the slag slurry obtains after separating by the washing of washing the joint machine is back to knotter by desander, repeating step (c12);
The technological parameter of scalping technology is: the concentration of advancing to starch of (1) slurry is 3%-5%, (2) the deslagging ratio is 10%-15%, (3) pressure that advances to starch of knotter is 250Kpa-350Kpa, (4) the operation pressure reduction of knotter is 20Kpa-80Kpa, (5) pressure that advances to starch of desander is 275Kpa-350Kpa, (6) sieve aperture of knotter is 9.5mm, and the sieve aperture of washing the joint machine is 9.5mm.
Wherein, described step (c2) adopts three sections pressurized screens, and two sections desanders and one section vibrating screen equipment carry out fine screen and is specially:
(c21), deliver to one section pressurized screen through the good stock pump that obtains after step (c1) processing;
(c22), in one section pressurized screen, the slurry of the fine screen by sieve seam enters subsequent processing, the slag slurry by the sieve seam does not enter two sections pressurized screens behind desander;
(c23), in two sections pressurized screens, in backflow of slurry to the section pressurized screen by sieve seam, repeating step (c22), the slag slurry by the sieve seam does not enter three sections pressurized screens behind desander;
(c24), in three sections pressurized screens, by repeating step (c23) in backflow of slurry to the two section pressurized screen of sieve seam, the slag slurry by the sieve seam does not enter vibrating screen;
(c25), in vibrating screen, isolated backflow of slurry to three section pressurized screen, repeating step (c24), the slag that sifts out slurry drain between waste residue reclaims.
The technological parameter of fine screen technology is: (1) one section pressurized screen: advancing to starch pressure is 250Kpa-350Kpa, and advancing to starch concentration is 2.8% ~ 3.2%, and the deslagging ratio is 10%-15%; (2) two sections pressurized screens: advancing to starch pressure is 250Kpa-350Kpa, and advancing to starch concentration is 1.2% ~ 1.3%, and the deslagging ratio is 8%-15%, and it is 275Kpa-350Kpa that desander advances to starch pressure; (3) three sections pressurized screens: advancing to starch pressure is 250Kpa-350Kpa, and advancing to starch concentration is 0.7% ~ 0.8%, and the deslagging ratio is 8%-13%, and it is 275Kpa-350Kpa that desander advances to starch pressure; (4) sieve of pressurized screen seam is wide is 0.2mm, and the sieve aperture of vibrating screen is 4.0mm.
In described step (d) washing, slightly wash and starch the system of washing and be made up of four wash engines that are connected in series, four wash engines are respectively first wash engine, second wash engine, the 3rd wash engine and the 4th wash engine; Slurry washs since first wash engine, the washings of the 4th wash engine are hot water, the filtrate that the washing of the 4th wash engine produces enters the 3rd wash engine as washings, the filtrate that the washing of the 3rd wash engine produces enters second wash engine as washings, and the filtrate that the washing of second wash engine produces enters first wash engine as washings.Slightly wash and starch the system of washing and adopt 4 wash engine countercurrent washings.
Wherein, the washings of described the 4th wash engine adding are 7m
3/ admt～8.5m
3/ admt, the wash degree≤350mg/l of the 4th wash engine, the wash degree of second wash engine is≤4000mg/l.
The technological parameter of wash engine is: (1) advances to starch concentration: 2.5%-4.0%; (2) advance to starch pressure: 50-70Kpa(3) pulp concentration: 10%-14%; (5) wash temperature: 80-95 ℃; (6) washing factor: 2.5.Described wash engine is closed wash engine or is the CB wash engine.
Described step (e) bleaching may further comprise the steps:
Wherein, step (e1) oxygen delignification adopts two sections oxygen delignifications.
The detailed process of oxygen delignification operation: add caustic soda and magnesium sulfate in the slurry after the wash engine washing concentrating, heat through low-pressure steam, again by in densely be pumped into dense blender in first section, adding oxygen mix in first section in the dense blender enters one section oxygen after evenly and takes off lifting/lowering formula stream reaction tube, slurry is at one section oxygen dealkylation reaction pipe, flows out after reaching technological requirement; The slurry that comes out from one section oxygen dealkylation reaction pipe heats through middle pressure steam, through in densely be pumped into dense blender in second section, it is even to add oxygen mix in second section in the dense blender, delivers to upflow tower, waits to reach to spurt after the technological requirement to oxygen and takes off in the blow bin standby.
The technological parameter of step (e1) oxygen delignification is as follows: (1) one section oxygen takes off technological parameter: starch dense: 8%-12%; NaOH:2.0%-3.0%(is to air dried pulp); Magnesium sulfate: 1-3kg/admt; Reaction temperature: 90-95 ℃; Flow of oxygen: 20-25kg/admt; Oxygen purity: 〉=93%; Oxygen pressure: 1.0-1.2Mpa; Reaction time: 5-10min.(2) two sections oxygen take off technological parameter: reaction temperature: 95-102 ℃; Flow of oxygen: 20-25kg/admt; Oxygen pressure: 1.0-1.2Mpa; Oxygen purity: 〉=93%; Reaction time: 60-80min; Up-flow tower top pressure: 300-600Kpa.
(e2) detailed process of ClO 2 bleaching is under the strong acid condition:
Dense standpipe during slurry is sent into after the wash engine washing concentrating, in add sulfuric acid in the dense standpipe, regulate pH; The slurry that therefrom dense standpipe comes out is sent into the middle pressure steam heater by middle underflow pump, uses Steam Heating; Dense blender during the slurry of therefrom pressing steam heater to come out enters, in add ClO 2 solution in the dense blender, mix; The slurry that therefrom dense blender comes out enters in the upflow tower, from the overflow of upflow tower top to downflow tower; Slurry is drawn to after the wash engine washing concentrating standby from downflow tower.
The technological parameter of ClO 2 bleaching under the strong acid condition: starch dense: 8%-12%; PH value: 2.0-3.0 before the reaction; Reaction temperature: 75-85 ℃; Chlorine dioxide consumption: 6-10 kg/admt; ClO 2 solution concentration: 9.0-10.0 g/l; Reaction time: 120-160min.
(e3) detailed process of hydrogen peroxide and the extracting of oxygen boosting alkali is:
With the slurry caustic soda in the stern notch of wash engine that obtains in the step (e2), regulate the pH value; Regulate slurry after the pH value enter in dense standpipe, in add hydrogen peroxide in the dense standpipe; Dense blender during the slurry that therefrom dense standpipe comes out is delivered to by middle underflow pump, in to add oxygen mix in the dense blender even; The slurry that therefrom dense blender comes out enters in the upflow tower, and overflowing from the upflow tower top is left to downflow tower, and slurry is in upflow tower and downflow tower reaction; Reaching the technological requirement disposed slurry, to be drawn to the wash engine washing concentrating from downflow tower standby.
The technological parameter of hydrogen peroxide and the extracting of oxygen boosting alkali: starch dense: 8%-12%; The NaOH consumption: 1.2%-1.8%(is to air dried pulp); PH value: 10.5-11.0 before the reaction; Hydrogen peroxide consumption: 3-5kg/admt; Flow of oxygen: 3-5kg/admt; Reaction time: 75-100min; Reaction temperature: 80-85 ℃.
(e4) detailed process of ClO 2 bleaching is: the slurry that step (e3) is obtained adds caustic soda at the wash engine stern notch, regulates the pH value; Regulate slurry after the pH value enter in dense standpipe, dense blender in sending into by middle underflow pump again, in dense blender adding ClO 2 solution, mix; The slurry that therefrom dense blender comes out enters in the upflow tower, and overflowing from the upflow tower top is left to downflow tower, and slurry is in upflow tower and downflow tower reaction; When the bleaching action tower bottom is extracted out, add hypo solution at slurry, in and the intact residual chlorine of unreacted in the slurry; Slurry after the neutralization is delivered to the wash engine washing concentrating, and the slurry after the washing concentrating enters finished product slurry tower and stores for future use.
The technological parameter of ClO 2 bleaching: starch dense: 8%-12%, pH value: 3.5-4.5 before the reaction; Chlorine dioxide consumption: 3-6 kg/admt; ClO 2 solution concentration: 9.0-10.0 g/l; Reaction time: 240-320min; Reaction temperature is 80-85 ℃; Sodium thiosulfate consumption: 0.5-2kg/admt; Concentration of sodium thiosulfate: 100-120g/l.
Described step (f) manufacture paper with pulp into: with the slurry that step (e) bleaching is handled, send into and destroy the forebay, after pumping and dilution, pass through two sections screenings of one-level and five sections desanding of one-level again, make bamboo wood dissolving pulp.
The parameter of step (f) papermaking process is: one section pressurized screen advances to starch pressure: 180-200KPa, one section pressurized screen advances to starch concentration: 3.5-4.5%, deslagging ratio :≤5%, one section desander advances to starch pressure: 160-180KPa, one section desander advances to starch concentration: 3.5-4.5%, manufactures paper with pulp quantitatively: 900-1200g/m
2Product quality requires: quantitatively: 900-1200, and whiteness: 〉=80%, moisture: 12-14%, alpha cellulose content: 〉=94%, reactivity worth (CS2 consumption 8ml) :≤250s, viscosity (cuprammonium): 9.0
+1.0mpa.s, pentosan :≤2.5, ash content :≤0.10, Fe
2O
3:≤20ppm.
After described step (f) is manufactured paper with pulp, also comprise step (g) post processing: bamboo wood dissolving pulp is entered head box, last net forming, squeezing, drying, cut paper, reason paper, packing and stock then.
The Kappa number of described bamboo wood dissolving pulp is 8～10, yield 〉=36%, first kind fiber content 〉=94%, S-18≤3.5%, pentosan content≤2.5%
Beneficial effect of the present invention is:The present invention has following advantage:
Boiling step of the present invention has following advantage:
(1) bamboo wood dissolving pulp that makes of the present invention, Kappa number is low, the intensity height; Deviating from a large number of hemicellulose and deviating from of part lignin have been realized, so when hot digestion, reduce alkali charge, the lumen of sheet stock is fully opened simultaneously, be beneficial to Extended Delignification, so Kappa number can further reduce, can reduce destruction, improve the output and the quality of bamboo wood dissolving pulp alpha-cellulose.(2) has the sealing gas recovery system, reduce the generation of sulfurous gas, reduce exhaust gas discharging, because temperature is useed usefulness as, do not need high curing degree just can keep the viscosity of bamboo wood dissolving pulp, require lowly than the sulphidity of the boiling method of traditional bamboo wood dissolving pulp, can reduce of the pollution of the malodorant of sulfur-bearing environment.(3) yield of raising bamboo wood dissolving pulp, cooking reaction is more complete, even, greatly reduces ash-retention efficiency, and digester yield is improved.(4) displacement washing is effective, saves cost, has improved the utilization rate of heat energy, and boiling temperature is more stable, and the alkali that lowers wash engine decreases; Because residual alkali reduces, the consumption of defoamer reduces thereupon in the pulp washing process.(5) because Kappa number reduces, reduce the consumption of bleaching medicine, reduce the expense of bleaching sewage disposal.(6) consumption of saving steam has reduced production cost.(7) the washing black liquid displacement cooking liquid that the system of washing produces is is slightly washed and starched in utilization, be equivalent to the bamboo wood dissolving pulp in the digester has been carried out first wash, the equipment input of reduction bamboo wood dissolving pulp washing stage, and be beneficial to and wash back bamboo wood dissolving pulp quality of stability.Make heat energy and the residue chemistry product amount of obtaining in the digester inner cooking liquid effectively reclaim simultaneously, reduced the consumption of product steam and the consumption of chemicals, reduce and use chemicals, make production cost reduce.(8) production process realizes full-automatic, efficient, high yield, low energy consumption, oligosaprobic production bamboo chemical dissolving pulp.
Screening step of the present invention has following advantage:
The scalping section advances to starch concentration height (operation concentration 3.8%, can be up to 5%), improved screening capacity, increased by one section desander than domestic existing scalping mode simultaneously, reduced of the wearing and tearing of heavy seeds such as the grains of sand, metallic particles, prolonged the service life of knotter to a great extent knotter; The closed screening modes that the fine screen section adopts three sections pressurized screens and two sections desanders to unite can be removed impurity such as fibre bundle in the slurry, sandstone to greatest extent, have improved screening effeciency, have prolonged the service life of pressurized screen simultaneously; Screening moves under the higher concentration condition, has reduced the water consumption and the fiber loss of system, enters black digestion liquid concentration height, the recovery that helps improving black liquor; Floor space is few, compact in design, and the efficient height, energy consumption is low.
Washing step of the present invention has following advantage: by the recycling to washings, saved water resource, alleviated waste water to environment damage.
Blanching step of the present invention has following advantage:
Adopt the mode of two sections oxygen delignifications, one section is the upwelling and down-welling tower, two sections is upflow tower, than one section oxygen delignification mode (lignin extrusion rate 35% ~ 40%), this technology has the reaction condition gentleness, and selectivity is strong, the obvious advantage of delignification rate height (45% ~ 55%), behind two sections delignifications, lignin content is lower in the slurry, but cellulose loss does not obviously increase; Slurry behind two sections oxygen delignifications, because lower than lignin content in the slurry of one section oxygen delignification mode, the required chemicals usage of following bleaching has obtained further reduction, thereby has saved bleaching cost; Behind two sections oxygen delignifications, lignin content in the slurry further reduces, waste water mesophytization oxygen demand (BOD), COD (COD), colourity, chemical residue and chlorination organic matter that the following bleaching zone produces will reduce largely, thereby reduce the influence to environment; Than the slurry that one section oxygen takes off or do not take off through peroxide, more stable through the slurry card valency behind two sections oxygen delignifications, guaranteed to float the back quality of stability; Two sections oxygen take off and have higher flexibility, can look brown stock character and bleached dissolving pulp quality requirement, and two sections temperature, pressure and alkali charge are adjusted; (PH=2-3) ClO 2 bleaching (D0) section under the strong acid condition, its effect is suitable with (the ClO 2 bleaching section+acid treatment section) two sections of present dissolving pulp production process, need not to carry out after bleaching acid treatment again; Carry out the strong acid ClO 2 bleaching before the EOP section earlier, greatly degree improves the bleaching effect (the EOP section increases whiteness 22-28%ISO) of EOP bleaching section hydrogen peroxide; Hydrogen peroxide and oxygen boosting alkali extracting (EOP), than modes such as the alkali extracting of generally adopting (E) and EO, O/P, PO, it is higher that the EOP mode is deviate from the residual lignin rate, it is stable to go out pulp brightness, the alkali extracting mode that this technology uses hydrogen peroxide and oxygen to strengthen, reduce the consumption of follow-up ClO 2 bleaching section (D1) chemicals, adding under the protectant condition of magnesium sulfate, improve alpha-cellulose quality in the slurry simultaneously; Through the dissolving pulp after the D0-EOP-D1 bleaching, pulp brightness, viscosity, the degree of polymerization are all stable, and iron ion content and ash content all satisfy technological requirement, and technology is simple, and cost is low, and sewage discharge is few.
The specific embodiment
The present invention is further illustrated with specific embodiment below, but the present invention is not subjected to the qualification of following embodiment.
Embodiment 1.
A kind of preparation method of bamboo wood dissolving pulp, it comprises following preparation process: (a) get the raw materials ready, (b) boiling, (c) screening, (d) washing, (e) bleaching, (f) manufacture paper with pulp.
Described step (a) is got the raw materials ready and is specially:
Bamboo wood is adopted drum slicer, and cutting growth 13mm～25mm, the sheet stock of thickness 3mm～5mm, sheet stock make it to sift out bamboo bits and underproof sheet stock, sheet stock qualification rate 〉=85% through double-deck classifying screen classification.Underproof sheet stock screens after the desintegrator cutting once more.Through screening qualified sheet stock,, send into the sheet stock stockyard after washing and the dehydration and deposit stand-by by the sheet rag tub.Bamboo wood is based on cizu, bambusa textile, sinocalamus latiflorus.
Described step (b) boiling may further comprise the steps:
(b1) steam dress pot; (b2) Steam Heating prehydrolysis; (b3) white liquid neutralization; (b4) hot black liquor displacement; (b5) temperature control heating and boiling make slurry; (b6) washing black liquid displacement, washing and cooling slurry; (b7) low temperature discharging.
Described step (b) boiling specifically may further comprise the steps:
(b1) steam dress pot: bamboo material is made sheet stock, be delivered to digester, feed low-pressure steam toward digester when carrying sheet stock; (b2) Steam Heating prehydrolysis: after steam dress pot is finished, use Steam Heating, make sheet stock prehydrolysis; (b3) white liquid neutralization: use in the white liquid in the white liquid bath of heat and sheet stock and steam condensate (SC) in the digester; (b4) hot black liquor displacement: with in the hot black liquor displacement cooking pot in the hot black liquor groove and waste liquid; (b5) temperature control is heated and boiling, makes the slurry of bamboo wood dissolving pulp; (b6) washing black liquid displacement, washing and cooling slurry; (b7) low temperature discharging.
Wherein, in the prehydrolysis of described step (b2) Steam Heating,, with the middle pressure steam heating, make the temperature in the digester reach 170 ℃ then earlier with the low-pressure steam heating; The pressure limit of low-pressure steam is 0.4Mpa, and the pressure limit of middle pressure steam is 0.9Mpa; Hydrolysis is by the control of P factor, and the scope of P factor is 500; The scope of the total time of Steam Heating prehydrolysis is 110 minutes.
Wherein, the white liquid neutralization of described step (b3) is with Na
2The O meter, the concentration of white liquid is 90g/l; The sulphidity of white liquid is 20%.
Wherein, the displacement of described (b4) hot black liquor is specially: before temperature control white liquid is joined hot black liquor, then hot black liquor is pumped into the pump entry of digester, be pumped into the top and the bottom of digester by circulating pump, carry out two-way replacement, in in the displacement cooking pot and waste liquid, in being replaced and the double-edged fine-toothed comb of waste liquid by the middle part of digester cement out.
In in the temperature control hot black liquor displacement cooking pot of hot black liquor feeder and waste liquid.In order to have required alkali charge between locomorphic stage, before temperature control, white liquid is joined hot black liquor at black liquor.
Hot black liquor is pumped into the digester pump entry.Hot black liquor is assigned to digester top and bottom in outlet of circulating pump.In the bottom of digester, bend pipe inlet and conical entrance use simultaneously, so that cooking liquor can be diffused into the entire cross section of digester.Come out by digester middle part double-edged fine-toothed comb with waste liquid in being replaced.Two-way replacement that Here it is.Compare with traditional up-flow displacement, two-way replacement can be used sizable flow and not damage metathesis in displacement.
Step (b4) afterwards, temperature be below 100 ℃ in and waste liquid send into the washing black liquid groove, as washing black liquid, standby; Temperature be more than 100 ℃ in and waste liquid send into warm black liquor feeder, standby.In more than 100 ℃ and a waste liquid part warm liquid that is used for next pot boiling charge, in remaining and waste liquid pumping evaporation.Get back to the hot black liquor feeder with waste liquid in the heat.
Wherein, described step (b5) is specially: heating adds middle pressure steam in the circulatory system by steam distributor, and in whole heating and digestion process, cooking liquor is extracted out from the double-edged fine-toothed comb at the middle part of digester, send the top and the bottom of digester then back to, continuously circulation.
Stewing temperature is 170 ℃; The H factor of boiling is 350; The time of temperature control heating and boiling is 42 minutes; With active alkali Na
2The O meter, alkali charge is 21%.
The technological parameter of the scalping technology of step (c1) is: the concentration of advancing to starch of (1) slurry is 3%, (2) the deslagging ratio is 10%, (3) pressure that advances to starch of knotter is 250Kpa, (4) the operation pressure reduction of knotter is 20Kpa, (5) pressure that advances to starch of desander is 275Kpa, (6) sieve aperture of knotter is 9.5mm, and the sieve aperture of washing the joint machine is 9.5mm.
The technological parameter of the fine screen technology of described step (c2) is: (1) one section pressurized screen: advancing to starch pressure is 250Kpa, and advancing to starch concentration is 2.8%, and the deslagging ratio is 10%; (2) two sections pressurized screens: advancing to starch pressure is 250Kpa, and advancing to starch concentration is 1.2%, and the deslagging ratio is 8%-15%, and it is 275Kpa that desander advances to starch pressure; (3) three sections pressurized screens: advancing to starch pressure is 250Kpa, and advancing to starch concentration is 0.7%, and the deslagging ratio is 8%-13%, and it is 275Kpa that desander advances to starch pressure; (4) sieve of pressurized screen seam is wide is 0.2mm, and the sieve aperture of vibrating screen is 4.0mm.
In described step (d) washing, the washings that the 4th wash engine adds are 7.8m
3/ admt, the wash degree of the 4th wash engine are 200 mg/l ~ 300mg/l, and the wash degree of second wash engine is 2600 mg/l ~ 4000mg/l.
The technological parameter of wash engine is: (1) advances to starch concentration: 3.0%; (2) advance to starch pressure: 58Kpa(3) pulp concentration: 12%; (5) wash temperature: 85 ℃; (6) washing factor: 2.5.Described wash engine is the CB wash engine, avoids foul smell excessive.
Described step (e) bleaching may further comprise the steps: (e1) oxygen delignification; (e2) ClO 2 bleaching under the strong acid condition; (e3) hydrogen peroxide and the extracting of oxygen boosting alkali; (e4) ClO 2 bleaching.
Wherein, step (e1) oxygen delignification adopts two sections oxygen delignifications, and detailed process is:
Add caustic soda and magnesium sulfate in the slurry after the wash engine washing concentrating, heat through low-pressure steam, again by in densely be pumped into dense blender in first section, adding oxygen mix in first section in the dense blender enters one section oxygen after evenly and takes off lifting/lowering formula stream reaction tube, slurry is at one section oxygen dealkylation reaction pipe, flows out after reaching technological requirement; The slurry that comes out from one section oxygen dealkylation reaction pipe heats through middle pressure steam, through in densely be pumped into dense blender in second section, it is even to add oxygen mix in second section in the dense blender, delivers to upflow tower, waits to reach to spurt after the technological requirement to oxygen and takes off in the blow bin standby.
The technological parameter of step (e1) oxygen delignification is as follows: (1) one section oxygen takes off technological parameter: starch dense: 8%; NaOH:2.0%(is to air dried pulp); Magnesium sulfate: 1kg/admt; Reaction temperature: 90 ℃; Flow of oxygen: 20kg/admt; Oxygen purity: 〉=93%; Oxygen pressure: 1.0Mpa; Reaction time: 5min.(2) two sections oxygen take off technological parameter: starch dense: 8%, and reaction temperature: 95 ℃; Flow of oxygen: 20kg/admt; Oxygen pressure: 1.0Mpa; Oxygen purity: 〉=93%; Reaction time: 60min; Up-flow tower top pressure: 300Kpa.
(e2) detailed process of ClO 2 bleaching is under the strong acid condition:
Dense standpipe during slurry is sent into after the wash engine washing concentrating, in add sulfuric acid in the dense standpipe, regulate pH; The slurry that therefrom dense standpipe comes out is sent into the middle pressure steam heater by middle underflow pump, uses Steam Heating; Dense blender during the slurry of therefrom pressing steam heater to come out enters, in add ClO 2 solution in the dense blender, mix; The slurry that therefrom dense blender comes out enters in the upflow tower, from the overflow of upflow tower top to downflow tower; Slurry is drawn to after the wash engine washing concentrating standby from downflow tower.
The technological parameter of ClO 2 bleaching under the strong acid condition: starch dense: 8%; PH value before the reaction: 2.0; Reaction temperature: 75 ℃; Chlorine dioxide consumption: 6 kg/admt; ClO 2 solution concentration: 9.0 g/l; Reaction time: 120min.
(e3) detailed process of hydrogen peroxide and the extracting of oxygen boosting alkali is:
With the slurry caustic soda in the stern notch of wash engine that obtains in the step (e2), regulate the pH value; Regulate slurry after the pH value enter in dense standpipe, in add hydrogen peroxide in the dense standpipe; Dense blender during the slurry that therefrom dense standpipe comes out is delivered to by middle underflow pump, in to add oxygen mix in the dense blender even; The slurry that therefrom dense blender comes out enters in the upflow tower, and overflowing from the upflow tower top is left to downflow tower, and slurry is in upflow tower and downflow tower reaction; Reaching the technological requirement disposed slurry, to be drawn to the wash engine washing concentrating from downflow tower standby.
The technological parameter of hydrogen peroxide and the extracting of oxygen boosting alkali: starch dense: 8%; The NaOH consumption: 1.2%(is to air dried pulp); PH value before the reaction: 10.5; Hydrogen peroxide consumption: 3kg/admt; Flow of oxygen: 3kg/admt; Reaction time: 75min; Reaction temperature: 80 ℃.
(e4) detailed process of ClO 2 bleaching is: the slurry that step (e3) is obtained adds caustic soda at the wash engine stern notch, regulates the pH value; Regulate slurry after the pH value enter in dense standpipe, dense blender in sending into by middle underflow pump again, in dense blender adding ClO 2 solution, mix; The slurry that therefrom dense blender comes out enters in the upflow tower, and overflowing from the upflow tower top is left to downflow tower, and slurry is in upflow tower and downflow tower reaction; When the bleaching action tower bottom is extracted out, add hypo solution at slurry, in and the intact residual chlorine of unreacted in the slurry; Slurry after the neutralization is delivered to the wash engine washing concentrating, and the slurry after the washing concentrating enters finished product slurry tower and stores for future use.
The technological parameter of ClO 2 bleaching: starch dense: 8%, pH value before the reaction: 3.5; Chlorine dioxide consumption: 3kg/admt; ClO 2 solution concentration: 9.0g/l; Reaction time: 240min; Reaction temperature is 80 ℃; Sodium thiosulfate consumption: 0.5kg/admt; Concentration of sodium thiosulfate: 100g/l.
Described step (f) manufacture paper with pulp into: with the slurry that step (e) bleaching is handled, send into and destroy the forebay, after pumping and dilution, pass through two sections screenings of one-level and five sections desanding of one-level again, make bamboo wood dissolving pulp.
The parameter of step (f) papermaking process is: one section pressurized screen advances to starch pressure: 180KPa, and one section pressurized screen advances to starch concentration: 3.5%, and the deslagging ratio: 3%, one section desander advances to starch pressure: 160KPa, and one section desander advances to starch concentration: 3.5%, manufacture paper with pulp quantitatively: 900g/m
2Product quality requires: quantitatively: 900 g/m
2, whiteness: 82%, moisture: 12%, alpha cellulose content: 94%, reactivity worth (CS2 consumption 8ml): 250s, viscosity (cuprammonium): 9.0mpa.s, pentosan: 2.5%, ash content: 0.10%, Fe
2O
3: 20ppm.
After described step (f) is manufactured paper with pulp, also comprise step (g) post processing: bamboo wood dissolving pulp is entered head box, last net forming, squeezing, drying, cut paper, reason paper, packing and stock then.
The Kappa number of described bamboo wood dissolving pulp is 8～10, and yield is 36% ~ 38%, and first kind fiber content is 94% ~ 95%, and S-18 is 3.0% ~ 3.5%, and pentosan content is 2.5%.
Embodiment 2.
The preparation method of a kind of bamboo wood dissolving pulp of present embodiment, it comprises following preparation process: (a) get the raw materials ready, (b) boiling, (c) screening, (d) washing, (e) bleaching, (f) manufacture paper with pulp.
The difference of present embodiment and embodiment 1 is:
In the described step (a), bamboo wood is adopted drum slicer, cutting growth 25mm～40mm, the sheet stock of thickness 4mm～6mm.
Wherein, in the prehydrolysis of described step (b2) Steam Heating,, with the middle pressure steam heating, make the temperature in the digester reach 173 ℃ then earlier with the low-pressure steam heating; The pressure limit of low-pressure steam is 0.5Mpa, and the pressure limit of middle pressure steam is 1.0Mpa; Hydrolysis is by the control of P factor, and the scope of P factor is 550; The scope of the total time of Steam Heating prehydrolysis is 120 minutes.
Wherein, the white liquid neutralization of described step (b3) is with Na
2The O meter, the concentration of white liquid is 94g/l; The sulphidity of white liquid is 25%.
Wherein, in the described step (b5), stewing temperature is 175 ℃; The H factor of boiling is 350; The time of temperature control heating and boiling is 30 minutes; With active alkali Na
2The O meter, alkali charge is 19%.
Wherein, in the described step (c1), the technological parameter of scalping technology is: the concentration of advancing to starch of (1) slurry is 4%, (2) the deslagging ratio is 12%, (3) pressure that advances to starch of knotter is 300Kpa, and the operation pressure reduction of (4) knotter is 50Kpa, and the pressure that advances to starch of (5) desander is 310Kpa, (6) sieve aperture of knotter is 9.5mm, and the sieve aperture of washing the joint machine is 9.5mm.
In the described step (c2), the technological parameter of fine screen technology is: (1) one section pressurized screen: advancing to starch pressure is 300Kpa, and advancing to starch concentration is 3.2%, and the deslagging ratio is 12%; (2) two sections pressurized screens: advancing to starch pressure is 300Kpa, and advancing to starch concentration is 1.3%, and the deslagging ratio is 10%, and it is 300Kpa that desander advances to starch pressure; (3) three sections pressurized screens: advancing to starch pressure is 300Kpa, and advancing to starch concentration is 0.8%, and the deslagging ratio is 10%, and it is 300Kpa that desander advances to starch pressure; (4) sieve of pressurized screen seam is wide is 0.2mm, and the sieve aperture of vibrating screen is 4.0mm.
In described step (d) washing, the washings that the 4th wash engine adds are 7m
3/ admt, the wash degree of the 4th wash engine are 350mg/l, and the wash degree of second wash engine is 4000mg/l.
The technological parameter of wash engine is: (1) advances to starch concentration: 2.5%; (2) advance to starch pressure: 50Kpa(3) pulp concentration: 10%; (5) wash temperature: 80 ℃; (6) washing factor: 2.5.Described wash engine is closed wash engine.
The technological parameter of step (e1) oxygen delignification is as follows: (1) one section oxygen takes off technological parameter: starch dense: 10%; NaOH:2.4%(is to air dried pulp); Magnesium sulfate: 2kg/admt; Reaction temperature: 92 ℃; Flow of oxygen: 22kg/admt; Oxygen purity: 〉=93%; Oxygen pressure: 1.1Mpa; Reaction time: 7min.(2) two sections oxygen take off technological parameter: starch dense: 10%, and reaction temperature: 97 ℃; Flow of oxygen: 22kg/admt; Oxygen pressure: 1.1Mpa; Oxygen purity: 〉=93%; Reaction time: 68min; Up-flow tower top pressure: 400Kpa.
The technological parameter of ClO 2 bleaching under step (e2) strong acid condition: starch dense: 10%; PH value before the reaction: 2.4; Reaction temperature: 80 ℃; Chlorine dioxide consumption: 7kg/admt; ClO 2 solution concentration: 9.4g/l; Reaction time: 140min.
The technological parameter of step (e3) hydrogen peroxide and the extracting of oxygen boosting alkali: starch dense: 10%; The NaOH consumption: 1.4%(is to air dried pulp); PH value before the reaction: 10.7; Hydrogen peroxide consumption: 4kg/admt; Flow of oxygen: 4kg/admt; Reaction time: 85min; Reaction temperature: 82 ℃.
The technological parameter of step (e4) ClO 2 bleaching: starch dense: 10%, pH value before the reaction: 4.0; Chlorine dioxide consumption: 5kg/admt; ClO 2 solution concentration: 10g/l; Reaction time: 280min; Reaction temperature is 82 ℃; Sodium thiosulfate consumption: 1kg/admt; Concentration of sodium thiosulfate: 110g/l.
The parameter of step (f) papermaking process is: one section pressurized screen advances to starch pressure: 190KPa, one section pressurized screen advances to starch concentration: 4.0%, and the deslagging ratio: 3.5%, one section desander advances to starch pressure: 170KPa, one section desander advances to starch concentration: 4.0%, manufacture paper with pulp quantitatively: 1000g/m
2Product quality requires: quantitatively: 1000 g/m
2, whiteness: 80%, moisture: 13%, alpha cellulose content: 95% ~ 97%, reactivity worth (CS2 consumption 8ml): 250s, viscosity (cuprammonium): 10.0mpa.s, pentosan: 1.5% ~ 2%, ash content: 0.10%, Fe
2O
3: 15ppm.
The Kappa number of described bamboo wood dissolving pulp is 8～9, and yield is 38% ~ 42%, and first kind fiber content is 95% ~ 97%, and S-18 is 1.0% ~ 2.0%, and pentosan content is 1.5% ~ 2%.
Unaccounted in the present embodiment feature adopts the explanation among the embodiment 1, no longer gives unnecessary details at this.
Embodiment 3.
The preparation method of a kind of bamboo wood dissolving pulp of present embodiment, it comprises following preparation process: (a) get the raw materials ready, (b) boiling, (c) screening, (d) washing, (e) bleaching, (f) manufacture paper with pulp.
The difference of present embodiment and embodiment 1 is:
In the described step (a), bamboo wood is adopted drum slicer, cutting growth 40mm～50mm, the sheet stock of thickness 6mm～7mm.
Wherein, in the prehydrolysis of described step (b2) Steam Heating,, with the middle pressure steam heating, make the temperature in the digester reach 175 ℃ then earlier with the low-pressure steam heating; The pressure limit of low-pressure steam is 0.6Mpa, and the pressure limit of middle pressure steam is 1.3Mpa; Hydrolysis is by the control of P factor, and the scope of P factor is 600; The scope of the total time of Steam Heating prehydrolysis is 130 minutes.
Wherein, the white liquid neutralization of described step (b3) is with Na
2The O meter, the concentration of white liquid is 97g/l; The sulphidity of white liquid is 30%.
Wherein, in the described step (b5), stewing temperature is 180 ℃; The H factor of boiling is 400; The time of temperature control heating and boiling is 50 minutes; With active alkali Na
2The O meter, alkali charge is 22%.
The technological parameter of the scalping technology of step (c1) is: the concentration of advancing to starch of (1) slurry is 5%, (2) the deslagging ratio is 15%, (3) pressure that advances to starch of knotter is 350Kpa, (4) the operation pressure reduction of knotter is 80Kpa, (5) pressure that advances to starch of desander is 350Kpa, (6) sieve aperture of knotter is 9.5mm, and the sieve aperture of washing the joint machine is 9.5mm.
The technological parameter of the fine screen technology of described step (c2) is: (1) one section pressurized screen: advancing to starch pressure is 350Kpa, and advancing to starch concentration is 3.5%, and the deslagging ratio is 15%; (2) two sections pressurized screens: advancing to starch pressure is 350Kpa, and advancing to starch concentration is 1.3%, and the deslagging ratio is 15%, and it is 350Kpa that desander advances to starch pressure; (3) three sections pressurized screens: advancing to starch pressure is 350Kpa, and advancing to starch concentration is 0.8%, and the deslagging ratio is 13%, and it is 350Kpa that desander advances to starch pressure; (4) sieve of pressurized screen seam is wide is 0.2mm, and the sieve aperture of vibrating screen is 4.0mm.
In described step (d) washing, the washings that the 4th wash engine adds are 8.5m
3/ admt, the wash degree of the 4th wash engine are 100mg/l, and the wash degree of second wash engine is 1000 mg/l ~ 2500mg/l.
The technological parameter of wash engine is: (1) advances to starch concentration: 4.0%; (2) advance to starch pressure: 70Kpa(3) pulp concentration: 14%; (5) wash temperature: 95 ℃; (6) washing factor: 2.5.Described wash engine is the CB wash engine, avoids foul smell excessive.
The technological parameter of step (e1) oxygen delignification is as follows: (1) one section oxygen takes off technological parameter: starch dense: 12%; NaOH:3.0%(is to air dried pulp); Magnesium sulfate: 3kg/admt; Reaction temperature: 95 ℃; Flow of oxygen: 25kg/admt; Oxygen purity: 〉=93%; Oxygen pressure: 1.2Mpa; Reaction time: 10min.(2) two sections oxygen take off technological parameter: starch dense: 12%, and reaction temperature: 102 ℃; Flow of oxygen: 25kg/admt; Oxygen pressure: 1.2Mpa; Oxygen purity: 〉=93%; Reaction time: 80min; Up-flow tower top pressure: 600Kpa.
The technological parameter of ClO 2 bleaching under step (e2) strong acid condition: starch dense: 12%; PH value before the reaction: 3.0; Reaction temperature: 85 ℃; Chlorine dioxide consumption: 10kg/admt; ClO 2 solution concentration: 9.0 g/l ~ 10.0g/l; Reaction time: 160min.
The technological parameter of step (e3) hydrogen peroxide and the extracting of oxygen boosting alkali: starch dense: 12%; The NaOH consumption: 1.8%(is to air dried pulp); PH value before the reaction: 11; Hydrogen peroxide consumption: 5kg/admt; Flow of oxygen: 5kg/admt; Reaction time: 100min; Reaction temperature: 85 ℃.
The technological parameter of step (e4) ClO 2 bleaching: starch dense: 12%, pH value before the reaction: 4.5; Chlorine dioxide consumption: 6kg/admt; ClO 2 solution concentration: 10g/l; Reaction time: 320min; Reaction temperature is 85 ℃; Sodium thiosulfate consumption: 2kg/admt; Concentration of sodium thiosulfate: 120g/l.
The parameter of step (f) papermaking process is: one section pressurized screen advances to starch pressure: 200KPa, one section pressurized screen advances to starch concentration: 4.5%, and the deslagging ratio: 5%, one section desander advances to starch pressure: 180KPa, one section desander advances to starch concentration: 4.5%, manufacture paper with pulp quantitatively: 1200g/m
2Product quality requires: quantitatively: 1200 g/m
2, whiteness: 83%, moisture: 14%, alpha cellulose content: 97% ~ 99%, reactivity worth (CS2 consumption 8ml): 200s, viscosity (cuprammonium): 8.0mpa.s, pentosan: 1.0% ~ 1.5%, ash content: 0.10%, Fe
2O
3: 18ppm.
The Kappa number of described bamboo wood dissolving pulp is 9～10, and yield is 37% ~ 40%, and first kind fiber content is 97% ~ 99%, and S-18 is 2.0% ~ 2.5%, and pentosan content is 1.0% ~ 1.5%.
Unaccounted in the present embodiment feature adopts the explanation among the embodiment 1, no longer gives unnecessary details at this.
The above embodiment, it is better embodiment of the present invention, be not to limit the scope of the present invention,, all should comprise in the patent claim of the present invention so all equivalences of doing according to the described structure of the present patent application claim, feature and principle change or modify.
Claims (9)
1. the preparation method of a bamboo wood dissolving pulp, it is characterized in that: it comprises following preparation process: (a) get the raw materials ready, (b) boiling, (c) screening, (d) washing, (e) bleaching, (f) manufacture paper with pulp;
Described step (b) boiling may further comprise the steps: (b1) steam dress pot; (b2) Steam Heating prehydrolysis; (b3) white liquid neutralization; (b4) hot black liquor displacement; (b5) temperature control heating and boiling make slurry; (b6) washing black liquid displacement, washing and cooling slurry; (b7) low temperature discharging;
Described step (c) screening may further comprise the steps: (c1) adopt one section desander, one section knotter and one section to wash the joint machine equipment and carry out scalping; (c2) adopt three sections pressurized screens, two sections desanders and one section vibrating screen equipment carry out fine screen;
Described step (d) washing is specially: dilution and screening slurry enter then and slightly wash and starch the system of washing and wash;
Described step (e) bleaching may further comprise the steps: (e1) oxygen delignification; (e2) ClO 2 bleaching under the strong acid condition; (e3) hydrogen peroxide and the extracting of oxygen boosting alkali; (e4) ClO 2 bleaching;
Wherein, described step (b) boiling specifically may further comprise the steps: (b1) steam dress pot: bamboo material is made sheet stock, be delivered to digester, feed low-pressure steam toward digester when carrying sheet stock; (b2) Steam Heating prehydrolysis: after steam dress pot is finished, use Steam Heating, make sheet stock prehydrolysis; (b3) white liquid neutralization: use in the white liquid in the white liquid bath of heat and sheet stock and steam condensate (SC) in the digester; (b4) hot black liquor displacement: with in the hot black liquor displacement cooking pot in the hot black liquor groove and waste liquid; (b5) temperature control is heated and boiling, makes the slurry of bamboo wood dissolving pulp; (b6) washing black liquid displacement, washing and cooling slurry; (b7) low temperature discharging.
2. the preparation method of a kind of bamboo wood dissolving pulp according to claim 1, it is characterized in that: described step (f) manufacture paper with pulp into: with the slurry that step (e) bleaching is handled, send into and destroy the forebay, after pumping and dilution, pass through two sections screenings of one-level and five sections desanding of one-level again, make bamboo wood dissolving pulp.
3. the preparation method of a kind of bamboo wood dissolving pulp according to claim 2, it is characterized in that: after described step (f) is manufactured paper with pulp, also comprise step (g) post processing: bamboo wood dissolving pulp is entered head box, last net forming, squeezing, drying, cut paper, reason paper, packing and stock then.
4. the preparation method of a kind of bamboo wood dissolving pulp according to claim 1 is characterized in that: in the prehydrolysis of described step (b2) Steam Heating, earlier with the low-pressure steam heating, with the middle pressure steam heating, make the temperature in the digester reach 170 ℃～175 ℃ then; The pressure limit of low-pressure steam is 0.4Mpa～0.6Mpa, and the pressure limit of middle pressure steam is 0.9Mpa～1.3Mpa; Hydrolysis is by the control of P factor, and the scope of P factor is 500～600; The scope of the total time of Steam Heating prehydrolysis is 110 minutes～130 minutes.
5. the preparation method of a kind of bamboo wood dissolving pulp according to claim 1, it is characterized in that: the displacement of described (b4) hot black liquor is specially: before temperature control white liquid is joined hot black liquor, then hot black liquor is pumped into the pump entry of digester, be pumped into the top and the bottom of digester by circulating pump, carry out two-way replacement, in in the displacement cooking pot and waste liquid, in being replaced and the double-edged fine-toothed comb of waste liquid by the middle part of digester cement out.
6. the preparation method of a kind of bamboo wood dissolving pulp according to claim 1 is characterized in that: described step (c1) adopts one section desander, one section knotter and one section to wash the joint machine equipment to carry out scalping and be specially:
(c11), the mashing pump after step (b) processing is delivered to knotter;
(c12), in knotter, the slurry of handling by the sieve aperture scalping enters subsequent processing, and the slag slurry by sieve aperture does not enter the joint machine of washing;
(c13), in washing the joint machine, after the knot in the slag slurry dries from the top spiral of washing the joint machine, drain between waste residue reclaims, and the slurry that the slag slurry obtains after separating by the washing of washing the joint machine is back to knotter by desander, repeating step (c12);
Described step (c2) adopts three sections pressurized screens, and two sections desanders and one section vibrating screen equipment carry out fine screen and is specially:
(c21), deliver to one section pressurized screen through the good stock pump that obtains after step (c1) processing;
(c22), in one section pressurized screen, the slurry of the fine screen by sieve seam enters subsequent processing, the slag slurry by the sieve seam does not enter two sections pressurized screens behind desander;
(c23), in two sections pressurized screens, in backflow of slurry to the section pressurized screen by sieve seam, repeating step (c22), the slag slurry by the sieve seam does not enter three sections pressurized screens behind desander;
(c24), in three sections pressurized screens, by repeating step (c23) in backflow of slurry to the two section pressurized screen of sieve seam, the slag slurry by the sieve seam does not enter vibrating screen;
(c25), in vibrating screen, isolated backflow of slurry to three section pressurized screen, repeating step (c24), the slag that sifts out slurry drain between waste residue reclaims.
7. the preparation method of a kind of bamboo wood dissolving pulp according to claim 1, it is characterized in that: in described step (d) washing, slightly wash and starch the system of washing and be made up of four wash engines that are connected in series, four wash engines are respectively first wash engine, second wash engine, the 3rd wash engine and the 4th wash engine; Slurry washs since first wash engine, the washings of the 4th wash engine are hot water, the filtrate that the washing of the 4th wash engine produces enters the 3rd wash engine as washings, the filtrate that the washing of the 3rd wash engine produces enters second wash engine as washings, and the filtrate that the washing of second wash engine produces enters first wash engine as washings.
8. the preparation method of a kind of bamboo wood dissolving pulp according to claim 7 is characterized in that: the washings that described the 4th wash engine adds are 7m
3/ admt～8.5m
3/ admt, the wash degree≤350mg/l of the 4th wash engine, the wash degree of second wash engine is≤4000mg/l.
9. the preparation method of a kind of bamboo wood dissolving pulp according to claim 8, it is characterized in that: the Kappa number of described bamboo wood dissolving pulp is 8～10, yield 〉=36%, first kind fiber content 〉=94%, S-18≤3.5%, pentosan content≤2.5%.
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| CN102704323B (en) * | 2012-06-29 | 2014-04-16 | 新乡市东升新材料有限公司 | Bamboo reed dissolving pulp pretreating method |
| CN102978993A (en) * | 2012-11-26 | 2013-03-20 | 四川银鸽竹浆纸业有限公司 | Bamboo fiber dissolving pulp and production technology thereof |
| CN104345125B (en) * | 2014-09-23 | 2016-02-17 | 周栋 | A kind of method of Fast Evaluation willow sulfate pulping technique |
| AU2015333547B2 (en) | 2014-10-15 | 2020-03-05 | Canfor Pulp Ltd | Integrated kraft pulp mill and thermochemical conversion system |
| CN107338666B (en) * | 2017-06-14 | 2019-08-13 | 广西金荣纸业有限公司 | A kind of method that sinocalamus latiflorus prepares bleached pulp |
| CN108589374A (en) * | 2018-05-22 | 2018-09-28 | 四川省犍为凤生纸业有限责任公司 | A kind of paper pulp manufacturing technique |
| CN109403118B (en) * | 2018-11-21 | 2021-02-02 | 湖南骏泰新材料科技有限责任公司 | Washing, selecting and bleaching method for preparing cellulose from agricultural and forestry residues |
| CN109706773A (en) * | 2018-12-29 | 2019-05-03 | 重庆理文卫生用纸制造有限公司 | A kind of pulping process of high-cleanness, high primary colors bamboo pulp |
| CN110904710A (en) * | 2019-11-06 | 2020-03-24 | 福建省青山纸业股份有限公司 | Bamboo pulp preparation process |
| CN110983848A (en) * | 2019-11-06 | 2020-04-10 | 福建省青山纸业股份有限公司 | Preparation process of bamboo unbleached pulp |
| CN112127193A (en) * | 2020-09-25 | 2020-12-25 | 福建省青山纸业股份有限公司 | Production process for improving quality index of dissolving pulp by using bleaching process |
| CN113882180B (en) * | 2021-08-27 | 2022-10-14 | 四川天竹竹资源开发有限公司 | Low-temperature replacement cooking method for bamboo kraft pulp |
| CN114855496B (en) * | 2022-04-15 | 2023-10-20 | 泰盛科技（集团）股份有限公司 | Bamboo fluff pulp preparation process and product thereof |
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| CN101457494A (en) * | 2008-12-24 | 2009-06-17 | 宜宾长毅浆粕有限责任公司 | Production method of bamboo chemical dissolving pulp |
| CN101463573A (en) * | 2008-12-08 | 2009-06-24 | 沅江纸业有限责任公司 | Straw pulp bleaching technique |
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| SE532370C2 (en) * | 2008-02-28 | 2009-12-29 | Metso Paper Inc | Method of bleaching a pulp |
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| CN101158122A (en) * | 2007-11-15 | 2008-04-09 | 宜宾纸业股份有限公司 | Bamboo dissolved pulp manufacturing technique |
| CN101235547A (en) * | 2008-03-06 | 2008-08-06 | 北京林业大学 | Method for producing bamboo dissolving pulp |
| CN101463573A (en) * | 2008-12-08 | 2009-06-24 | 沅江纸业有限责任公司 | Straw pulp bleaching technique |
| CN101457494A (en) * | 2008-12-24 | 2009-06-17 | 宜宾长毅浆粕有限责任公司 | Production method of bamboo chemical dissolving pulp |
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