CN106702799A - Method for preparing dissolving wood pulp for viscose fibers by modifying papermaking-grade wood pulp - Google Patents
Method for preparing dissolving wood pulp for viscose fibers by modifying papermaking-grade wood pulp Download PDFInfo
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- CN106702799A CN106702799A CN201611093675.0A CN201611093675A CN106702799A CN 106702799 A CN106702799 A CN 106702799A CN 201611093675 A CN201611093675 A CN 201611093675A CN 106702799 A CN106702799 A CN 106702799A
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- wood pulp
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- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C7/00—Digesters
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C1/00—Pretreatment of the finely-divided materials before digesting
- D21C1/06—Pretreatment of the finely-divided materials before digesting with alkaline reacting compounds
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C11/00—Regeneration of pulp liquors or effluent waste waters
- D21C11/04—Regeneration of pulp liquors or effluent waste waters of alkali lye
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
- D21C9/02—Washing ; Displacing cooking or pulp-treating liquors contained in the pulp by fluids, e.g. wash water or other pulp-treating agents
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
- D21C9/10—Bleaching ; Apparatus therefor
- D21C9/1026—Other features in bleaching processes
- D21C9/1036—Use of compounds accelerating or improving the efficiency of the processes
Abstract
The invention provides a method for preparing dissolving wood pulp for viscose fibers by modifying papermaking-grade wood pulp, wherein the method comprises the following steps: crushing, hydrolysis, washing, beating and defibering, desanding, alkali soaking, squeezing dealkalization, secondary washing, acid treatment, and third-time washing; in the hydrolysis step, the papermaking-grade wood pulp after crushing and water are added into a spherical boiler according to the bath ratio of 1:4, then are heated up to 165-172 DEG C, are subjected to heat preservation for 2-3 h and are hydrolyzed. No any chemicals are added in the hydrolysis step, high temperature hydrolysis is carried out directly, and aggregation reduction and partial impurity removal of the wood pulp are achieved; a traditional high-temperature and high-alkali cooking aggregation-reduction way is changed, chemical materials are saved, the production cost is reduced, at the same time, the formation of pulping black liquor and waste gas is avoided, and a part of hydrolysate can be reused, so that subsequent sewage treatment is simpler and more feasible, and the pollution to the environment is greatly reduced.
Description
Technical field
Dissolved the present invention relates to the technical field of modification of papermaking grade wood pulp, more particularly to a kind of modified preparation of papermaking grade wood pulp
The method of wood pulp.
Background technology
Viscose rayon, is to glue fine full name, is called ice silk, silk-cotton, is a principal item of staple fibre.Viscous fibre is
With the cellulose fibre that cotton or other natural fibers are produced as raw material.In 12 kinds of main textile fabrics, fine moisture percentage is glued most
Meet the physiological requirement of human body skin, with smooth nice and cool, ventilative, antistatic, antiultraviolet, the features such as lucuriant in design.
Domestic enterprise is more using Cotton Pulp as the raw materials for production of viscose rayon, and Cotton Pulp, also known as refined cotton pulp, is short with cotton
Down as raw material, through the refined a kind of high purity cellulose of alkaline cooking, rinsing.Recently as the hair of viscose rayon industry
Exhibition, glues the quick increase of fibre production capacity, and the resource of cotton linter is restricted and increasingly shortage by cultivated area and growth cycle, and raw material is short
Lack the development for seriously having constrained China's viscose rayon industry, there is lack of raw materials turns into the bottleneck of industry development.Therefore, existing enterprise
Dissolving pulp is produced for viscose glue, but the price of import dissolving pulp is high, shortage, have impact on normal operation and the economy of enterprise
Benefit, finds the substitute of dissolving pulp, is a vital task of enterprise.
China has voluntarily produced with import substantial amounts of papermaking grade wood pulp plate, but because papermaking grade wood pulp plate has the degree of polymerization
The shortcomings of high, reactivity worth difference and non-cellulosic impurity content high, the production of viscose rayon can't be directly used in, it is necessary to will make
Paper level wood pulp is modified, and is prepared into dissolving pulp, for production viscose rayon.At present, the country is with papermaking grade wood pulp plate
Raw material is prepared in the method for dissolving pulp, and majority is still traditional soda cooking, is largely changed using NaOH, bleeding agent etc.
Product, black digestion liquid colourity is high, COD is high, and sewage disposal difficulty is big, does not meet energy-conservation, emission reduction policy that China pushes；Additionally,
During also a small number of enterprises are to the processing procedure of papermaking grade wood pulp, without cooking process, using the poly- side of alkali steeping after bleaching drop
Formula prepares dissolving pulp, though the method saves production cost, it is to avoid and the formation of black digestion liquid, bleaching drop is poly- to fiber freedom
Hydroxyl destruction is serious, and obtained wood pulps reactivity worth is poor, and addition that can only be a small amount of coordinates with import dissolving pulp or cotton pulp
For the production of viscose rayon.
The content of the invention
The present invention is in view of the shortcomings of the prior art, there is provided a kind of papermaking grade wood pulp is modified to prepare viscose rayon dissolving pulp
Method.
The present invention is achieved through the following technical solutions, there is provided a kind of papermaking grade wood pulp is modified to prepare viscose rayon with molten
The method for solving wood pulp, methods described comprises the following steps：Crush, hydrolysis, washing, mashing are discongested, desanding, alkali steeping, squeezing are de-
Alkali, secondary washing, acid treatment, three washings；Wherein, the hydrolysing step is according to over dry wood by the papermaking grade wood pulp after crushing
The mass ratio starched with water is 1:4-5 is added in rotary spherical digester, is then heated to 165-172 DEG C of insulation 2-3h and is hydrolyzed.
Over dry wood pulp is also referred to as bath raio with the mass ratio of water, can be with negligible when the water content of slurry is very low, it is believed that be
The mass ratio of wood pulp and water.
In the present invention, hydrolysing step is that the wood pulp after crushing is put into rotary spherical digester, without any chemicals, is directly entered
Row pyrohydrolysis, is gathered and part removal of impurities with the drop for realizing wood pulp；In the case of high temperature adds water, in hemicellulose contained by raw material of wood pulp
Acetyl group and the continuous dissolution of furfural acidic group form acetic acid and furfural acid, cause hydrolyzate pH value constantly to decline, and then form acid
Hydrolysis so that the hemicellulose in raw material of wood pulp is largely degraded dissolution, the degraded dissolution of part acid soluble lignin, realize wood
Starch the part removal of non-cellulosic impurity, meanwhile, hydrolyzate can also realize part inorganic salts in wood pulp, vegetable soda, tannin,
Other non-cellulosic impurities such as pigment, pectic substance are effectively removed, so as to realize the purification of cellulose.Additionally, acidic hydrolysis is caused
The portion fractures of cellulose glucoside key, make long-chain become short chain, and the drop for realizing wood pulp cellulose is gathered.In hydrolysing step, by adjustment
Holding temperature and soaking time can control the degree of polymerization between 480-650.
Preferably, the acid treatment step is to be made into the slurry after secondary washing to starch dense（The mass fraction of oven dry stock）For
4-6%, the pulp solution of pH value≤2, then to addition auxiliary agent reaction 30-50min in the pulp solution for preparing, the auxiliary agent
Addition is the 2-2.5 ‰ of oven dry stock quality, and described auxiliary agent includes the component of following mass fraction：Sodium chlorite：55-70%；
Sulfamic acid：8-15%；EDTA：3-7%；Dodecyl sodium sulfate：8-12%；Calgon：5-10%；Oxalic acid：5-10%.
Preferably, stirred in adding assistant to when adding auxiliary agent in the pulp solution for preparing, continue to stir 10- after adding
20min, then stops stirring and continues to react 20-30min.
The present invention adds auxiliary agent as described above in acid treatment step, and its mechanism of action is molten further to remove lignin
Go out chromophoric group, and smaller is damaged to cellulose, pulp reactivity worth is not influenceed；Meanwhile, color development metal ion is gone
Remove.Two above aspect so that half pulp brightness is improved.The advantage of the auxiliary agent added in acid treatment of the present invention is not influence
In the case of pulp viscosity, pulp whiteness can be greatly improved, and the existing general bleaching assistant of in the market is while improve whiteness,
Larger is influenceed on pulp viscosity；Meanwhile, the more general bleaching assistant of this auxiliary agent can improve pulp whiteness 2% or so more.
Preferably, the desanding step uses the desanding mode of three sections of hydrocyclone two grade, the slurry after being discongested to mashing
Material carries out desanding, and the desanding time is 60-100 minutes/ball, and it is 0.2-0.3% to starch dense, and pressure is 0.1-0.2Mpa, during desanding
Controlled by regulation except mortar is dense and pressure can be controlled to half stuff dirt count, in the present invention softwood pulp dirt count≤
140mm2/kg；Hardwood pulp dirt count≤100mm2/kg；
Herein, in two grades three sections, " level " refers to the scummer hop count that good slurry passes through, and " section " refers to the scummer of slurry process
Hop count, slurry is dense to refer to the oven dry stock concentration that slurry enters desander.
Preferably, the alkali steeping step is to allocate the slurry after desanding into temperature for 20-30 DEG C, and concentration is 70-100g/
1-2h is kept in L sodium hydroxide solutions, wherein, oven dry stock concentration is 4-6% in sodium hydroxide solution.
Preferably, the secondary washing uses horizontal belt vacuum pulp washing machine, and slurry is carried out with the backwater after acid treatment
Three sections of countercurrent washings, enter to starch concentration for 2-3%, and dilution gfactor is 2-3.
Herein, three sections of countercurrent washings refer to the 3rd section and are washed with the backwater after acid treatment, and third wash liquid is used for the
Second wash, second wash liquid is washed for first paragraph.Purpose is to reach optimal clean result with minimum water consumption.When
So, if carrying out this step for the first time, due to not carrying out follow-up acid treatment also, therefore the 3rd section can be entered with running water
Row washing, then washs third wash liquid for second segment, and second wash liquid is washed for first paragraph, if not for the first time
This step is carried out, had been carried out before explanation, then acid treatment step has also been carried out, then, the 3rd section can use acid treatment
Backwater washing afterwards.When dilution gfactor refers to washing air dried pulp per ton, into the water in waste liquid.
Preferably, in the squeezing dealkalize step, the recycle of alkali liquor that will deviate from after adding new alkali, is back to alkali steeping step
Suddenly.Half stuff pentosan and resin content can be controlled with process time by the way that the alkali for adjusting alkali steeping is dense, control is more in the present invention
Pentose≤4.0%；Control resin≤0.5% of softwood pulp, resin≤0.4% of hardwood pulp.
Preferably, the washing step is to bleed off the waste gas in the rotary spherical digester after the completion of hydrolysis, then to the slurry after hydrolysis
Water is squeezed into material, when starching dense 2-3%, cleaning solution is discharged.Cleaning solution can enter trench and enter environmental protection treatment.
Preferably, it is the backwater after desanding to the water squeezed into the slurry after hydrolysis in the washing step.To save water
Resource.Certainly, as described in above-mentioned secondary washing process, if carrying out this step for the first time, then follow-up desanding step is also
Do not carry out, it is also just available without the backwater after desanding, just can be washed with running water, when being done before removing
The backwater after desanding is reused after sand step to be washed.
Preferably, lap machine slurrying is also included after three washing steps：Slurry after described three times are washed is adopted
It is 7-13% that moisture is made of lap machine, and pH value is the pulpboard of 5.5-7.5.
Preferably, in three washing steps：First with the water deviate from lap machine slurrying by the slurry after acid treatment
Washing 30-60min, then with originally water washing 30-60min.
Three washings are the catabolites in order to will be generated in acid treatment course of reaction（Cellulose, half fibre under sour environment
Dimension element, lignin etc. can all occur a certain degree of degraded, generate new material）, metal ion and hydrochloric acid wash away, cardboard is used first
The backwater of machine abjection is washed, and its main purpose is the water consumption for saving follow-up originally water washing, reduces production cost, but complete
Full washing with backwater is unable to reach requirement, it is therefore desirable to plus the preceding paragraph originally water washing, make Impurity removal effect more preferable.Certainly,
As described above washing and secondary washing described in, if for the first time carry out, then three times wash before do not carried out cardboard also
Machine pulping stage, it is also just available without backwater, then, twice washing in three washings can use running water, when three
After having carried out lap machine pulping stage before secondary washing, just three washings can be carried out using the water deviate from lap machine slurrying
First pass washing.
In the present invention, in acid treatment step and three washing steps, by controlling the auxiliary dosage and wash time length can
To adjust half pulp brightness, irony, ash content index, the present invention half pulp brightness >=82.0% of control, irony≤20ppm；Ash content≤
0.12%。
Technical scheme provided in an embodiment of the present invention can include following beneficial effect：
The present invention provides a kind of papermaking grade wood pulp and is modified the method for preparing viscose rayon dissolving pulp, and methods described includes as follows
Step：Crush, hydrolysis, washing, mashing discongest, desanding, alkali steeping, squeezing dealkalize, secondary washing, acid treatment, three times washing；Its
In, the hydrolysing step is by bath raio 1 by the papermaking grade wood pulp and water after crushing:4-5 is added in rotary spherical digester, then heats to 165-
172 DEG C of insulation 2-3h are hydrolyzed.Without any chemicals in hydrolysing step of the invention, pyrohydrolysis is directly carried out,
Gathered and part removal of impurities with the drop for realizing wood pulp；Change traditional high temperature, alkaline boiling high and drop poly- mode, save chemical industry material, drop
While low production cost, it is to avoid black liquor of pulp making, the formation of waste gas, and partial hydrolysis liquid can reuses so that follow-up sewage
Treatment is more simple, feasible, greatly reduces the pollution to environment.
Specific embodiment
In order that those skilled in the art more fully understand the technical scheme in the present invention, below to the embodiment of the present invention
In technical scheme be clearly and completely described, it is clear that described embodiment is only a part of embodiment of the invention,
Rather than whole embodiments.Based on the embodiment in the present invention, those skilled in the art are not before creative work is made
The every other embodiment for being obtained is put, should all belong to protection scope of the present invention.
Embodiment 1
The embodiment of the present invention provides a kind of papermaking grade wood pulp and is modified the method for preparing viscose rayon dissolving pulp, and methods described is pressed
Carried out according to following steps：
S101：Crush：To papermaking level softwood pulp board raw material stripping and slicing；Because wood-pulp board raw material volume is larger, and in hydrolysing step
Rotary spherical digester ball it is mouthful smaller, if not processing wood-pulp board, directly charging difficulty is larger, therefore carries out stripping and slicing to it, is beneficial to
Rotary spherical digester feeds.
S102：Hydrolysis：By the wood pulp after above-mentioned stripping and slicing, without any chemicals, according to over dry wood pulp with water
Mass ratio 1:In 4 addition rotary spherical digesters, then heat to 165 DEG C of insulation 2h and be hydrolyzed, the waste gas in ball is put after the completion of hydrolysis, with
Reduce pressure in ball.Without any chemicals in hydrolysing step, directly carry out pyrohydrolysis, with the drop for realizing wood pulp it is poly- and
Part removal of impurities；Change traditional high temperature, alkaline boiling high and drop poly- mode, save chemical industry material, while reducing production cost, keep away
Exempt from the formation of black liquor of pulp making, waste gas, and partial hydrolysis liquid can reuse so that follow-up sewage disposal is more simple, feasible, greatly
The big pollution reduced to environment.
S103：Washing：Slurry after hydrolysis deposits in the pond below rotary spherical digester（Pond under ball）It is interior, to the slurry in pond under ball
Running water is squeezed into, during slurry dense 2%, cleaning solution trench is entered into（Enter environmental protection treatment）, the slurry after washing is beaten.Herein, due to
It is to carry out that papermaking grade wood pulp is modified to prepare viscose rayon dissolving pulp for the first time, follow-up desanding step is not carried out also, does not have
Have produce desanding or backwater, therefore, washed using running water, when carrying out, papermaking grade wood pulp is modified to prepare viscose rayon
After with dissolving pulp, such as the wood pulp after the second ball hydrolysis can then be washed with the backwater of the first ball desanding.
S104：Mashing is discongested：It is beaten by the way of trough-style pulp beater tip-tap slurry, to realize discongesting slurry.
S105：Desanding：Using three sections of desanding mode of hydrocyclone two grade, desanding is carried out to slurry, the desanding time is
60 minutes；Oven dry stock concentration into the slurry in desander is 0.2%；Pressure 0.1Mpa.
S106：Alkali steeping：It is 25 DEG C that slurry after desanding is added into temperature, and concentration is in the sodium hydroxide solution of 70g/L
1h is kept, wherein, oven dry stock concentration is 5% in sodium hydroxide solution.
S107：Squeezing dealkalize：Slurry is processed using acroll press washer, alkali lye is reclaimed, after adding new alkali, subsequent alkaline is back to
Dipping.
S108：Secondary washing：Using horizontal belt vacuum pulp washing machine, three sections of countercurrent washings are carried out：3rd section with running water
Washing, third wash liquid is washed for second segment, and second wash liquid is washed for first paragraph；It is 2%, dilution gfactor to enter to starch concentration
It is 2.Herein, due to being to carry out that papermaking grade wood pulp is modified to prepare viscose rayon dissolving pulp for the first time, do not carry out also follow-up
Acid treatment step, without the backwater produced after acid treatment, therefore, third wash is carried out using running water, when making
Paper level wood pulp is modified prepare viscose rayon dissolving pulp after, such as the second ball wood pulp for hydrolyzing, then can with the first ball it is sour at
Backwater after reason is washed.
S109：Acid treatment：By starching dense it is 5% by the slurry after secondary washing, it is molten that the process conditions of pH value=2 are made into slurry
Liquid, then adds auxiliary agent while stirring, and the auxiliary dosage to oven dry stock is 2 ‰, and timing is started after adding auxiliary agent, after 10 minutes,
Stop stirring placing 20 minutes, acid treatment terminates；Wherein, described auxiliary agent includes the component of following mass fraction：Sodium chlorite：
60%；Sulfamic acid：10%；EDTA：5%；Dodecyl sodium sulfate：10%；Calgon：7%；Oxalic acid：8%.In the present invention, help
The addition of agent substantially increases the whiteness of product so that bleaching process is not needed in technological process, simplifies production procedure, improves
Operating efficiency, and realize energy-saving, bleaching effluent is not produced, reduce the pollution to environment.
S1010：Three washings：Washed twice with running water, 30min is washed every time.Herein, due to being to be made for the first time
Paper level wood pulp is modified to prepare viscose rayon dissolving pulp, and follow-up lap machine pulping stage is not carried out also, no to produce back
Water, therefore, wash washed using running water twice, when carrying out, papermaking grade wood pulp is modified to prepare viscose rayon dissolving
After wood pulp, the first pass washing that the water that can deviate from lap machine slurrying is used in three washings, such as the second ball wood for hydrolyzing
When slurry carries out three washings, the backwater produced when can carry out lap machine slurrying with the first ball wood pulp carries out first pass and washs.
Three washings are the catabolites in order to will be generated in acid treatment course of reaction（Cellulose, half fibre under sour environment
Dimension element, lignin etc. can all occur a certain degree of degraded, generate new material）, metal ion and hydrochloric acid wash away, cardboard is used first
The backwater of machine abjection is washed, and its main purpose is the water consumption for saving follow-up originally water washing, reduces production cost, but complete
Full washing with backwater is unable to reach requirement, it is therefore desirable to plus the preceding paragraph originally water washing, make Impurity removal effect more preferable.
S1011：Lap machine slurrying：It is 7% to use lap machine to be made moisture in the above-mentioned slurry stated after three washings,
PH value is 5.5 pulpboard.
Embodiment 2
The embodiment of the present invention provides a kind of papermaking grade wood pulp and is modified the method for preparing viscose rayon dissolving pulp, and methods described is pressed
Carried out according to following steps：
S101：Crush：To papermaking level hardwood pulp board raw material stripping and slicing；Because wood-pulp board raw material volume is larger, and in hydrolysing step
Rotary spherical digester ball it is mouthful smaller, if not processing wood-pulp board, directly charging difficulty is larger, therefore carries out stripping and slicing to it, is beneficial to
Rotary spherical digester feeds.
S102：Hydrolysis：By the wood pulp after above-mentioned stripping and slicing, without any chemicals, according to over dry wood pulp with water
Mass ratio 1:In 4 addition rotary spherical digesters, then heat to 172 DEG C of insulation 3h and be hydrolyzed, the waste gas in ball is put after the completion of hydrolysis, with
Reduce pressure in ball.Without any chemicals in hydrolysing step, directly carry out pyrohydrolysis, with the drop for realizing wood pulp it is poly- and
Part removal of impurities；Change traditional high temperature, alkaline boiling high and drop poly- mode, save chemical industry material, while reducing production cost, keep away
Exempt from the formation of black liquor of pulp making, waste gas, and partial hydrolysis liquid can reuse so that follow-up sewage disposal is more simple, feasible, greatly
The big pollution reduced to environment.
S103：Washing：Slurry after hydrolysis deposits in the pond below rotary spherical digester（Pond under ball）It is interior, to the slurry in pond under ball
The backwater squeezed into after desanding, during slurry dense 3%, trench is entered by cleaning solution（Enter environmental protection treatment）, the slurry after washing is beaten.
S104：Mashing is discongested：It is beaten by the way of trough-style pulp beater tip-tap slurry, to realize discongesting slurry.
S105：Desanding：Using three sections of desanding mode of hydrocyclone two grade, desanding is carried out to slurry, the desanding time is
100 minutes；Oven dry stock concentration into the slurry in desander is 0.3%；Pressure 0.2Mpa.
S106：Alkali steeping：It is 20 DEG C to allocate the slurry after desanding into temperature, and concentration is in the sodium hydroxide solution of 100g/L
2h is kept, wherein, oven dry stock concentration is 4% in sodium hydroxide solution.
S107：Squeezing dealkalize：Slurry is processed using acroll press washer, alkali lye is reclaimed, after adding new alkali, subsequent alkaline is back to
Dipping.
S108：Secondary washing：Using horizontal belt vacuum pulp washing machine, three sections of countercurrent washings are carried out：3rd section was entered with last time
Backwater washing after row acid treatment, third wash liquid is washed for second segment, and second wash liquid is washed for first paragraph；Enter and starch dense
It is 3% to spend, and dilution gfactor is 3.
S109：Acid treatment：By starching dense it is that the process conditions of 4%, pH=1 are made into pulp solution by the slurry after secondary washing,
Then auxiliary agent is added while stirring, and the auxiliary dosage to oven dry stock is 2.5 ‰, and timing is started after adding auxiliary agent, after 20 minutes, is stopped
Only stirring is placed 30 minutes, and acid treatment terminates；Wherein, described auxiliary agent includes the component of following mass fraction：Sodium chlorite：
55%；Sulfamic acid：15%；EDTA：3%；Dodecyl sodium sulfate：8%；Calgon：10%；Oxalic acid：9%.In the present invention, help
The addition of agent substantially increases the whiteness of product so that bleaching process is not needed in technological process, simplifies production procedure, improves
Operating efficiency, and realize energy-saving, bleaching effluent is not produced, reduce the pollution to environment.
S1010：Three washings：First with the water deviate from last time lap machine slurrying by the slurry washing after acid treatment
60min, then with originally water washing 60min.
Three washings are the catabolites in order to will be generated in acid treatment course of reaction（Cellulose, half fibre under sour environment
Dimension element, lignin etc. can all occur a certain degree of degraded, generate new material）, metal ion and hydrochloric acid wash away, cardboard is used first
The backwater of machine abjection is washed, and its main purpose is the water consumption for saving follow-up originally water washing, reduces production cost, but complete
Full washing with backwater is unable to reach requirement, it is therefore desirable to plus the preceding paragraph originally water washing, make Impurity removal effect more preferable.
S1011：Lap machine slurrying：It is 13% to use lap machine to be made moisture in the above-mentioned slurry stated after three washings,
PH value is 7.5 pulpboard.
Embodiment 3
The embodiment of the present invention provides a kind of papermaking grade wood pulp and is modified the method for preparing viscose rayon dissolving pulp, and methods described is pressed
Carried out according to following steps：
S101：Crush：To papermaking level softwood pulp board raw material stripping and slicing；Because wood-pulp board raw material volume is larger, and in hydrolysing step
Rotary spherical digester ball it is mouthful smaller, if not processing wood-pulp board, directly charging difficulty is larger, therefore carries out stripping and slicing to it, is beneficial to
Rotary spherical digester feeds.
S102：Hydrolysis：By the wood pulp after above-mentioned stripping and slicing, without any chemicals, according to over dry wood pulp with water
Mass ratio 1:In 5 addition rotary spherical digesters, then heat to 170 DEG C of insulation 3h and be hydrolyzed, the waste gas in ball is put after the completion of hydrolysis, with
Reduce pressure in ball.
S103：Washing：Slurry after hydrolysis deposits in the pond below rotary spherical digester（Pond under ball）It is interior, to the slurry in pond under ball
The backwater squeezed into after desanding, during slurry dense 3%, trench is entered by cleaning solution（Enter environmental protection treatment）, the slurry after washing is beaten.
S104：Mashing is discongested：It is beaten by the way of trough-style pulp beater tip-tap slurry, to realize discongesting slurry.
S105：Desanding：Using three sections of desanding mode of hydrocyclone two grade, desanding is carried out to slurry, the desanding time is
80 minutes；Oven dry stock concentration into the slurry in desander is 0.3%；Pressure 0.2Mpa.
S106：Alkali steeping：It is 30 DEG C to allocate the slurry after desanding into temperature, and concentration is in the sodium hydroxide solution of 80g/L
2h is kept, wherein, oven dry stock concentration is 6% in sodium hydroxide solution.
S107：Squeezing dealkalize：Slurry is processed using acroll press washer, alkali lye is reclaimed, after adding new alkali, subsequent alkaline is back to
Dipping.
S108：Secondary washing：Using horizontal belt vacuum pulp washing machine, three sections of countercurrent washings are carried out：3rd section was entered with last time
Backwater washing after row acid treatment, third wash liquid is washed for second segment, and second wash liquid is washed for first paragraph；Enter and starch dense
It is 3% to spend, and dilution gfactor is 2.
S109：Acid treatment：By starching dense it is that the process conditions of 6%, pH=1 are made into pulp solution by the slurry after secondary washing,
Then auxiliary agent is added while stirring, and the auxiliary dosage to oven dry stock is 2.5 ‰, and timing is started after adding auxiliary agent, after 10 minutes, is stopped
Only stirring is placed 20 minutes, and acid treatment terminates；Wherein, described auxiliary agent includes the component of following mass fraction：Sodium chlorite：
70%；Sulfamic acid：8%；EDTA：4%；Dodecyl sodium sulfate：8%；Calgon：5%；Oxalic acid：5%.
S1010：Three washings：First with the water deviate from last time lap machine slurrying by the slurry washing after acid treatment
60min, then with originally water washing 60min.
S1011：Lap machine slurrying：It is 10% to use lap machine to be made moisture in the above-mentioned slurry stated after three washings,
PH value is 6 pulpboard.
Embodiment 4
The embodiment of the present invention provides a kind of papermaking grade wood pulp and is modified the method for preparing viscose rayon dissolving pulp, and methods described is pressed
Carried out according to following steps：
S101：Crush：To papermaking level hardwood pulp board raw material stripping and slicing, in slurry is put into rotary spherical digester；
S102：Hydrolysis：By the wood pulp after above-mentioned stripping and slicing, without any chemicals, according to over dry wood pulp with water matter
Amount compares 1:In 4 addition rotary spherical digesters, then heat to 172 DEG C of insulation 3h and be hydrolyzed, the waste gas in ball is put after the completion of hydrolysis, to reduce
Pressure in ball.
S103：Washing：Slurry after hydrolysis deposits in the pond below rotary spherical digester（Pond under ball）It is interior, to the slurry in pond under ball
The backwater squeezed into after desanding, during slurry dense 3%, trench is entered by cleaning solution, and the cleaning solution of discharge can carry out environmental protection treatment, after washing
Slurry carry out mashing and discongest.
S104：Mashing is discongested：It is beaten by the way of trough-style pulp beater tip-tap slurry, realization is discongested to slurry.
S105：Desanding：Using three sections of desanding mode of hydrocyclone two grade, desanding is carried out to slurry, the desanding time is
100 minutes；Oven dry stock concentration into the slurry in desander is 0.3%；Pressure 0.2Mpa.
S106：Alkali steeping：It is 25 DEG C that slurry after desanding is added into temperature, and concentration is in the sodium hydroxide solution of 100g/L
2h is kept, wherein, oven dry stock concentration is 5% in sodium hydroxide solution.
S107：Squeezing dealkalize：Slurry is processed using acroll press washer, alkali lye is reclaimed, after adding new alkali, subsequent alkaline is back to
Dipping.
S108：Secondary washing：Using horizontal belt vacuum pulp washing machine, three sections of countercurrent washings are carried out：3rd section was entered with last time
Backwater washing after row acid treatment, third wash liquid is washed for second segment, and second wash liquid is washed for first paragraph；Enter and starch dense
It is 3% to spend, and dilution gfactor is 3.
S109：Acid treatment：By starching dense it is that the process conditions of 5%, pH=1 are made into pulp solution by the slurry after secondary washing,
Then auxiliary agent is added while stirring, and the addition of the auxiliary agent is the 2.5 ‰ of oven dry stock quality, and timing is started after adding auxiliary agent,
Stop stirring after 20 minutes, then place 30 minutes, acid treatment terminates；Wherein, described auxiliary agent includes following mass fraction
Component：Sodium chlorite：55%；Sulfamic acid：10%；EDTA：7%；Dodecyl sodium sulfate：12%；Calgon：6%；Oxalic acid：
10%。
S1010：Three washings：First with the water deviate from last time lap machine slurrying by the slurry washing after acid treatment
60min, then with originally water washing 60min.
S1011：Lap machine slurrying：It is 10% to use lap machine to be made moisture in the above-mentioned slurry stated after three washings,
PH value is 6 pulpboard.
The indices of the dissolving pulp prepared in above-described embodiment are as shown in the table：
As seen from the above table, the whiteness of dissolving pulp product obtained in the method that the present invention is provided is high, the fine content of first is high, and ash, iron contain
Amount is low, and reactivity worth is good, and waste liquid COD contents are low, the need for fully meeting viscose rayon production.And the method that the present invention is provided
In, change traditional high temperature, alkaline boiling high and drop poly- mode, using the hydrolysis method without any chemicals, to realize
And part of impurity removal poly- to the drop of papermaking grade wood pulp, save chemical industry material, while reducing production cost, it is to avoid slurrying
The formation of black liquor, waste gas, and partial hydrolysis liquid can reuse so that follow-up sewage disposal is more simple, feasible, greatly reduces
Pollution to environment.In addition, the auxiliary agent added in acid treatment operation, substantially increases the whiteness of product so that in technological process
Bleaching process is not needed, production procedure is simplified, operating efficiency is improve, and realizes energy-saving, do not produce bleaching effluent,
Reduce the pollution to environment.
Certainly, described above is also not limited to the example above, technical characteristic of the present invention without description can by or
Realized using prior art, will not be repeated here；Above example and to be merely to illustrate technical scheme be not right
Limitation of the invention, with reference to being preferred embodiment described in detail to the present invention, one of ordinary skill in the art should
Work as understanding, change that those skilled in the art are made in essential scope of the invention, retrofit, add or replace
Change without departure from spirit of the invention, should also belong to claims of the invention.
Claims (10)
1. a kind of papermaking grade wood pulp is modified the method for preparing viscose rayon dissolving pulp, it is characterised in that methods described includes
Following steps：Crush, hydrolysis, washing, mashing are discongested, desanding, alkali steeping, squeezing dealkalize, secondary washing, acid treatment, wash for three times
Wash；Wherein, the hydrolysing step be by the papermaking grade wood pulp after crushing according to over dry wood pulp with water mass ratio be 1:4-5 is added
In rotary spherical digester, then heat to 165-172 DEG C of insulation 2-3h and be hydrolyzed.
2. papermaking grade wood pulp according to claim 1 is modified the method for preparing viscose rayon dissolving pulp, and its feature exists
It is that the slurry after secondary washing is made into slurry dense is 4-6%, the pulp solution of pH value≤2, Ran Houxiang in, the acid treatment step
Auxiliary agent reaction 30-50min is added in the pulp solution for preparing, the addition of the auxiliary agent is the 2-2.5 ‰ of oven dry stock quality, institute
The auxiliary agent stated includes the component of following mass fraction：Sodium chlorite：55-70%；Sulfamic acid：8-15%；EDTA：3-7%；12
Sodium alkyl sulfonate：8-12%；Calgon：5-10%；Oxalic acid：5-10%.
3. papermaking grade wood pulp according to claim 2 is modified the method for preparing viscose rayon dissolving pulp, and its feature exists
In in the desanding step, using three sections of desanding mode of hydrocyclone two grade, the desanding time is 60-100min/ balls, slurry
Dense is 0.2-0.3%, and pressure is 0.1-0.2Mpa.
4. papermaking grade wood pulp according to claim 3 is modified the method for preparing viscose rayon dissolving pulp, and its feature exists
It is that the slurry after desanding is added into temperature is 20-30 DEG C in, the alkali steeping step, concentration is that 70-100g/L NaOH is molten
1-2h is kept in liquid, wherein, the oven dry stock concentration in sodium hydroxide solution is 4-6%.
5. papermaking grade wood pulp according to claim 4 is modified the method for preparing viscose rayon dissolving pulp, and its feature exists
In, the secondary washing uses horizontal belt vacuum pulp washing machine, and three sections of countercurrent washings are carried out to slurry with the backwater after acid treatment,
Enter to starch concentration for 2-3%, dilution gfactor is 2-3.
6. papermaking grade wood pulp according to claim 5 is modified the method for preparing viscose rayon dissolving pulp, and its feature exists
In in the squeezing dealkalize step, the recycle of alkali liquor that will deviate from after adding new alkali, is back to alkali steeping step.
7. papermaking grade wood pulp according to claim 6 is modified the method for preparing viscose rayon dissolving pulp, and its feature exists
In, the washing step be to adding water in the slurry after hydrolysis, when starching dense 2-3%, cleaning solution is discharged.
8. papermaking grade wood pulp according to claim 7 is modified the method for preparing viscose rayon dissolving pulp, and its feature exists
In being backwater after desanding to the water added in the slurry after hydrolysis in the washing step.
9. the papermaking grade wood pulp according to claim any one of 1-8 is modified the method for preparing viscose rayon dissolving pulp,
Characterized in that, also including lap machine slurrying after three washing steps：Slurry after described three times are washed uses paper
Trigger is made moisture for 7-13%, and pH value is the pulpboard of 5.5-7.5.
10. papermaking grade wood pulp according to claim 9 is modified the method for preparing viscose rayon dissolving pulp, and its feature exists
In in three washing steps：First with the water deviate from lap machine slurrying by the slurry washing 30-60min after acid treatment,
Then with originally water washing 30-60min.
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| CN109338790A (en) * | 2018-09-04 | 2019-02-15 | 江苏星光新材料科技有限公司 | A kind of environmental protection wood pulp technique |
| CN110886123A (en) * | 2019-11-14 | 2020-03-17 | 新疆中泰纺织集团有限公司 | Method for producing viscose fiber by modifying reed natural color paper pulp |
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