CN111962320A - Sulfate pulping process for industrial hemp - Google Patents
Sulfate pulping process for industrial hemp Download PDFInfo
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- CN111962320A CN111962320A CN202010800619.6A CN202010800619A CN111962320A CN 111962320 A CN111962320 A CN 111962320A CN 202010800619 A CN202010800619 A CN 202010800619A CN 111962320 A CN111962320 A CN 111962320A
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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
- D21C3/00—Pulping cellulose-containing materials
- D21C3/02—Pulping cellulose-containing materials with inorganic bases or alkaline reacting compounds, e.g. sulfate processes
- D21C3/022—Pulping cellulose-containing materials with inorganic bases or alkaline reacting compounds, e.g. sulfate processes in presence of S-containing compounds
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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
- D21C3/00—Pulping cellulose-containing materials
- D21C3/22—Other features of pulping processes
- D21C3/26—Multistage processes
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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
- 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
- D21C9/06—Washing ; Displacing cooking or pulp-treating liquors contained in the pulp by fluids, e.g. wash water or other pulp-treating agents in filters ; Washing of concentrated pulp, e.g. pulp mats, on filtering surfaces
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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
- 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
- D21C9/16—Bleaching ; Apparatus therefor with per compounds
- D21C9/163—Bleaching ; Apparatus therefor with per compounds with peroxides
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- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21D—TREATMENT OF THE MATERIALS BEFORE PASSING TO THE PAPER-MAKING MACHINE
- D21D5/00—Purification of the pulp suspension by mechanical means; Apparatus therefor
- D21D5/02—Straining or screening the pulp
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- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H11/00—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only
- D21H11/12—Pulp from non-woody plants or crops, e.g. cotton, flax, straw, bagasse
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- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
- D21H17/03—Non-macromolecular organic compounds
- D21H17/05—Non-macromolecular organic compounds containing elements other than carbon and hydrogen only
- D21H17/14—Carboxylic acids; Derivatives thereof
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
- D21H17/20—Macromolecular organic compounds
- D21H17/21—Macromolecular organic compounds of natural origin; Derivatives thereof
- D21H17/24—Polysaccharides
- D21H17/28—Starch
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- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
- D21H21/14—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by function or properties in or on the paper
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/64—Paper recycling
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- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Wood Science & Technology (AREA)
- Mechanical Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Paper (AREA)
Abstract
The invention discloses a sulfate pulping process of industrial hemp, which belongs to the technical field of papermaking and comprises the following specific pulping steps: preparing materials: peeling industrial hemp, cutting into pieces, and storing in a storage bin for later use; and (3) cooking: feeding industrial hemp fragments into a vertical digester for cooking to obtain slurry; washing: performing four-section countercurrent washing on the slurry treated in the step 2; screening: removing large slag from the slurry treated in the step 3 by using a knot remover, removing coarse non-steamed fiber bundle components by using a pressure screen, and removing silt and other dust brought by industrial hemp by using a sand remover; bleaching: single-stage bleaching the finished pulp treated in the step 4 by adopting hydrogen peroxide to obtain industrial hemp finished pulp; pulping: pulping the finished pulp to obtain a finished product; the process method effectively widens the pulping raw material resources, relieves the pressure of insufficient supply of the raw materials, reduces the cost of the pulping raw materials, and the prepared pulp has good water absorption, high physical strength and good dustproof performance and can completely meet the production requirements of paper.
Description
Technical Field
The invention belongs to the technical field of papermaking, and particularly relates to a sulfate pulping process of industrial hemp.
Background
In recent years, with the shortage of papermaking raw materials, in order to reduce the production cost of a pulping factory, optimize the structure of raw materials and realize the diversification of fiber raw materials, a large number of pulping enterprises are urgently hoped to find out more pulping raw materials and develop pulping technologies of corresponding raw materials so as to adapt to the change of the wood raw material market and reduce the dependence degree on imported wood pulp.
Industrial cannabis refers to cannabis with Tetrahydrocannabinol (THC) content below 0.3%. Hemp is mainly classified into hemp for fiber and hemp for seed and fiber (for oil). Mature industrial hemp (fiber and seed dual-purpose variety) grows in partial areas with the altitude of 800-1700m in Yunnan and under the climatic conditions, the plant height is usually 1.5-3.5m, even more than 4 m; the diameter of the stem is 10-35mm, and the diameter of the stem is more than 40 mm. The yield of the hemp stalks per mu is 650 plus 850kg, and 40-75kg of hemp seeds are harvested. The hemp plants are gradually lignified after growing, developing and maturing, and form a hollow middle part, the phloem part of the stems accounts for about 20-30%, and the stem core part accounts for about 70-80%; the bast has high cellulose content, long fiber and low lignin content; the cellulose content, the fiber length and the lignin content of the stalk core are all similar to those of hardwood. The industrial hemp is used in the fields of textile, paper making, food, packaging, medicine, daily chemical and the like and is a classical production material.
Disclosure of Invention
Aiming at the problems in the prior art, the invention aims to provide a sulfate pulping process for industrial hemp, which effectively widens the pulping raw material resources, relieves the pressure of insufficient supply of raw materials, reduces the cost of the pulping raw materials, and produces pulp with good water absorption, high physical strength and good dustproof performance, thereby completely meeting the paper production requirements.
In order to realize the purpose, the invention adopts the technical scheme that:
a sulfate pulping process of industrial hemp comprises the following specific pulping steps:
step 1, preparing materials: peeling industrial hemp, cutting into pieces with length of 12-28mm and qualification rate of more than 95%, and storing in a feed bin;
step 2, cooking: feeding the industrial hemp fragments obtained by the treatment in the step 1 into a vertical digester for cooking to obtain pulp, wherein the main cooking parameters are as follows: the cooking liquor ratio is controlled to be 1: 4-5, the effective cooking time is 100-;
step 3, washing: performing four-stage countercurrent washing on the pulp treated in the step 2, wherein the residual alkali in the washed pulp is less than or equal to 150 mg/L;
and 4, screening: removing large slag from the slurry treated in the step 3 by using a knot remover, removing coarse non-steamed fiber bundle components by using a pressure screen, and removing silt and other dust brought by industrial hemp by using a sand remover;
and step 5, bleaching: single-stage bleaching the finished pulp treated in the step 4 by adopting hydrogen peroxide to obtain industrial hemp finished pulp, wherein the consumption of the hydrogen peroxide is 8-10kg/t pulp;
step 6, pulping: and (5) pulping the finished pulp obtained in the step (5) to obtain a finished product, wherein the pulping concentration is controlled to be 5-8%, and the pulping degree is less than or equal to 45 DEG SR.
Further, the cooking heating mode in the step 2 is an early stage indirect heating mode, a later stage direct heating mode, and heating is divided into two times, the temperature is raised to 125 ℃ for the first time, small air release is carried out for 2-3 times, the temperature is raised to 168 ℃ for the second time, small air release is carried out for 5-10 times, and the heat preservation time is not less than 50 min.
Further, after the cooking in the step 2 is finished, the non-digested components in the finished pulp are less than or equal to 2.3 percent, and the kappa number is controlled to be 15-50.
Furthermore, the Baume degree of the black liquor after washing in the step 3 is more than or equal to 8.0 DEG B, the free alkali of the black liquor is more than or equal to 5.0g/L, and the fiber content of the black liquor is less than or equal to 0.01 g/L.
Further, the pulp formed after bleaching in the step 5 has the ISO whiteness of 29-31 percent and the tearing index of more than or equal to 15.0mN.m2G, wet weight is more than or equal to 18g, and dust degree is less than or equal to 1.5mm2/m2。
Further, 1.0-2.0kg/t of paper water absorption height improver A and 0.1-0.2kg/t of paper curing agent are added during pulping in the step 6.
Further, the water absorption height improver A is a mixture of acrylonitrile graft copolymer starch and sodium alginate.
Further, the curing agent is p-hydroxybenzene sulfonic acid.
Further, the addition ratio of the mixture of the acrylonitrile graft copolymer starch and the sodium alginate is 3: 2.
the invention has the beneficial effects that: (1) the industrial hemp adopted by the invention has high utilization value of the whole body, the whole stem of the industrial hemp can be made into pulp with good quality, and the generated residue pulp is hemp long fiber with good quality and can be applied to other fields;
(2) the small air release is carried out during the first temperature rise of the cooking so as to discharge non-condensable gas and further tumble wood chips, and the small air release is carried out for a plurality of times during the second temperature rise, so that the non-condensable gas can be discharged, the heat in the pot can be convected, the upper temperature, the lower temperature and the middle temperature tend to be consistent, and the cooking uniformity is improved; in the cooking process, the ratio of cooking liquor is controlled well, the quantity of the cooking liquor cannot be too large, a proper space is reserved, otherwise, the residual space in the pot is insufficient, the liquor cannot be overturned sufficiently, local insufficient cooking is easily generated, and green sheets are generated, and on the other hand, the excessive liquor quantity and overcooking caused by too low quantity of the cooking liquor in the pot are prevented, so that the excessive cooking liquor quantity is generated, the excessive degradation of papermaking semi-fibers is caused, and the yield is influenced;
(3) the water absorption height improver A is added in the pulping process, wherein the acrylonitrile graft copolymer starch enables the water absorption height of the prepared pulp to be obviously improved, the water absorption of the pulp is greatly improved, paper types with requirements on the water absorption height such as wet curtain paper can be manufactured, the product quality is ensured, but the paper strength is reduced along with the improvement of the water absorption height, the water absorption height improver A also adds sodium alginate, the acrylonitrile graft copolymer starch can permeate into fiber gaps and form a hydrophilic layer coated film, the compatibility is better when the three components of hemp fiber, sodium alginate and acrylonitrile graft copolymer starch are compounded, the acrylonitrile graft copolymer starch and the hemp fiber are more tightly crosslinked after the sodium alginate is added, the fiber gap density is increased, the generated hydrophilic layer coated film is more compact, and the hydrophilic layer coated film strength is effectively improved, in addition, a curing agent is added in pulping, and further the coating of the pulp is strengthened, so that the surface of the produced paper is fine and smooth, the electrostatic effect is greatly reduced, and the paper has the dustproof performance.
Detailed Description
For a better understanding of the present invention, embodiments of the present invention are described in detail below with reference to examples, but those skilled in the art will understand that the following examples are only for illustrating the present invention and should not be construed as limiting the scope of the present invention.
Example 1:
a sulfate pulping process of industrial hemp comprises the following specific pulping steps:
step 1, preparing materials: peeling industrial hemp, cutting into pieces with length of 12-20mm and qualification rate of 96%, and storing in a feed bin;
step 2, cooking: feeding the industrial hemp fragments obtained by the treatment in the step 1 into a vertical digester for cooking to obtain a pulp, wherein the non-cooked component in the pulp is 2.3%, the kappa number is controlled at 50, and the main cooking parameters are as follows: the cooking liquor ratio is controlled to be 1: 4, the effective cooking time is 100min, the alkali consumption is 20%, the vulcanization degree is 16%, the highest pressure is controlled to be 0.68MPa, the highest temperature is increased to 168 ℃, the cooking temperature rising mode is an early stage indirect temperature rising mode, a later stage direct temperature rising mode is adopted, the temperature rising mode is divided into two times, the temperature rising mode is carried out for the first time to 115 ℃, 2 times of small air release are carried out, the temperature rising mode is carried out for the second time to 168 ℃, 5 times of small air release are carried out, and the heat preservation time;
step 3, washing: performing four-stage countercurrent washing on the pulp treated in the step 2, wherein the residual alkali in the washed pulp is 150mg/L, the baume degree of the washed black liquor is 8.0 DEG B, the free alkali in the black liquor is 5.0g/L, and the fiber content in the black liquor is 0.01 g/L;
and 4, screening: removing large slag from the slurry treated in the step 3 by using a knot remover, removing coarse non-steamed fiber bundle components by using a pressure screen, and removing silt and other dust brought by industrial hemp by using a sand remover;
and step 5, bleaching: the pulping treated in the step 4 is subjected to single-stage bleaching by adopting hydrogen peroxide to obtain industrial hemp pulping, the consumption of the hydrogen peroxide is 8kg/t of the pulping, the ISO whiteness of the bleached pulping is 29%, and the tearing index is 15.0mN.m2(g), wet weight 18g, dust degree 1.5mm2/m2；
Step 6, pulping: pulping the finished pulp obtained in the step 5 to obtain a finished product, wherein the pulping concentration is controlled to be 5%, the pulping degree is 45 DEG SR, adding 1.0kg/t of paper water absorption height improver A and 0.1kg/t of paper p-hydroxybenzene sulfonic acid during pulping, wherein the water absorption height improver A is a mixture of acrylonitrile graft copolymer starch and sodium alginate, and the adding proportion of the mixture of the acrylonitrile graft copolymer starch and the sodium alginate is 3: 2.
example 2:
a sulfate pulping process of industrial hemp comprises the following specific pulping steps:
step 1, preparing materials: peeling industrial hemp, cutting into pieces with length of 15-28mm and qualification rate of 98%, and storing in a feed bin for later use;
step 2, cooking: feeding the industrial hemp fragments obtained by the treatment in the step 1 into a vertical digester for cooking to obtain a pulp, wherein the non-cooked component in the pulp is 2.0%, the kappa number is controlled to be 15, and the main cooking parameters are as follows: the cooking liquor ratio is controlled to be 1: 5, the effective cooking time is 120min, the alkali consumption is 15%, the vulcanization degree is 23%, the highest pressure is controlled to be 0.80MPa, the highest temperature is increased to 160 ℃, the cooking temperature rising mode is an early stage indirect temperature rising mode, a later stage direct temperature rising mode is adopted, the temperature rising mode is divided into two times, the temperature rising mode is carried out for the first time to 125 ℃, 3 times of small air release are carried out, the temperature rising mode is carried out for the second time to 160 ℃, 10 times of small air release are carried out, and the heat preservation;
step 3, washing: performing four-stage countercurrent washing on the pulp treated in the step 2, wherein the residual alkali in the washed pulp is 130mg/L, the baume degree of the washed black liquor is 9.0 DEG B, the free alkali in the black liquor is 5.5g/L, and the fiber content in the black liquor is 0.008 g/L;
and 4, screening: removing large slag from the slurry treated in the step 3 by using a knot remover, removing coarse non-steamed fiber bundle components by using a pressure screen, and removing silt and other dust brought by industrial hemp by using a sand remover;
and step 5, bleaching: the pulping treated in the step 4 is subjected to single-stage bleaching by adopting hydrogen peroxide to obtain industrial hemp pulping, the consumption of the hydrogen peroxide is 10kg/t of the pulping, the ISO whiteness of the bleached pulping is 31%, and the tearing index is 18.0mN.m2(g), wet weight 20g, dust degree 1.3mm2/m2；
Step 6, pulping: pulping the finished pulp obtained in the step 5 to obtain a finished product, wherein the pulping concentration is controlled to be 8%, and the pulping degree is 40 DEG SR, adding 2.0kg/t of paper water absorption height improver A and 0.2kg/t of paper p-hydroxybenzene sulfonic acid during pulping, wherein the water absorption height improver A is a mixture of acrylonitrile graft copolymer starch and sodium alginate, and the adding proportion of the mixture of the acrylonitrile graft copolymer starch and the sodium alginate is 3: 2.
example 3:
a sulfate pulping process of industrial hemp comprises the following specific pulping steps:
step 1, preparing materials: peeling industrial hemp, cutting into pieces with length of 15-24mm and qualification rate of more than 97%, and storing in a feeding bin for later use;
step 2, cooking: feeding the industrial hemp fragments obtained by the treatment in the step 1 into a vertical digester for cooking to obtain a pulp, wherein the non-cooked component in the pulp is 2.2%, the kappa number is controlled to be 25, and the main cooking parameters are as follows: the cooking liquor ratio is controlled to be 1: 4.5, the effective cooking time is 110min, the alkali consumption is 18%, the vulcanization degree is 20%, the highest pressure is controlled to be 0.75MPa, the highest temperature is 165 ℃, the cooking temperature rise mode is an early-stage indirect temperature rise mode, a later-stage direct temperature rise mode is adopted, the temperature rise is carried out in two times, the temperature rise is carried out for the first time to 120 ℃, 2 times of small air release are carried out, the temperature rise is carried out for the second time to 165 ℃, 8 times of small air release are carried out, and the heat preservation time is;
step 3, washing: performing four-stage countercurrent washing on the pulp treated in the step 2, wherein the residual alkali in the washed pulp is 145mg/L, the baume degree of the washed black liquor is 8.5 DEG B, the free alkali in the black liquor is 6.0g/L, and the fiber content in the black liquor is 0.007 g/L;
and 4, screening: removing large slag from the slurry treated in the step 3 by using a knot remover, removing coarse non-steamed fiber bundle components by using a pressure screen, and removing silt and other dust brought by industrial hemp by using a sand remover;
and step 5, bleaching: the pulping treated in the step 4 is subjected to single-stage bleaching by adopting hydrogen peroxide to obtain industrial hemp pulping, the consumption of the hydrogen peroxide is 9kg/t of the pulping, the ISO whiteness of the bleached pulping is 30%, and the tearing index is 19.0mN.m2(g), wet weight 19g, dust degree 1.2mm2/m2；
Step 6, pulping: pulping the finished pulp obtained in the step 5 to obtain a finished product, wherein the pulping concentration is controlled to be 7%, and the pulping degree is 35 DEG SR, adding 1.5kg/t of paper water absorption height improver A and 0.13kg/t of paper p-hydroxybenzene sulfonic acid during pulping, wherein the water absorption height improver A is a mixture of acrylonitrile graft copolymer starch and sodium alginate, and the adding proportion of the mixture of the acrylonitrile graft copolymer starch and the sodium alginate is 3: 2.
comparative example 1:
comparative example 1 is different from the above examples in that the water absorption level improving agent is not added at the time of beating process, only p-hydroxybenzenesulfonic acid is added, and the rest of the process steps are the same as example 1.
Comparative example 2:
comparative example 2 is different from the above examples in that acrylonitrile graft copolymerized starch and p-hydroxybenzene sulfonic acid in the water absorption height improver a were separately added at the time of beating process without adding sodium alginate, and the remaining process steps were the same as in example 1.
Comparative example 3:
comparative example 3 is different from the examples in that the water absorption level improver A is added during the beating process without adding p-hydroxybenzene sulfonic acid, and the remaining process steps are the same as those of example 1.
The slurries prepared in the above examples and comparative examples were applied to paper manufacture, and physical indicators of the manufactured and inserted paper were measured, and the results of the measurements are shown in table 1.
TABLE 1
As can be seen from Table 1, the industrial hemp chemical pulp prepared by the present invention has good water absorption and high physical strength, and the dustproof performance is good, the production requirement of paper can be completely met, further analysis is carried out, the paper forming rate of the pulp prepared by adopting the process of the water absorption height improver A is higher than that of the pulp which is not adopted, the water absorption performance is better, and the further analysis is carried out, the mixture of the acrylonitrile graft copolymer starch and the sodium alginate is adopted as the water absorption height improver A, the water absorption performance is better and the dustproof performance is better than that of the acrylonitrile graft copolymer starch which is adopted as the water absorption height improver A alone, and the paper prepared by adopting the process of the curing agent has higher physical strength and better dustproof performance than the paper which is not adopted, which indicates that the finished paper produced by the pulp made of industrial hemp has good water absorption, meanwhile, the physical strength is high, the dustproof performance is good, and a water absorption height improver A and p-hydroxybenzene sulfonic acid must be added simultaneously in the pulping process.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above-described embodiments. Those skilled in the art should appreciate that many modifications and variations are possible in light of the above teaching without departing from the scope of the invention.
Claims (9)
1. The sulfate pulping process of industrial hemp is characterized by comprising the following specific pulping steps:
step 1, preparing materials: peeling industrial hemp, cutting into pieces with length of 12-28mm and qualification rate of more than 95%, and storing in a feed bin;
step 2, cooking: feeding the industrial hemp fragments obtained by the treatment in the step 1 into a vertical digester for cooking to obtain pulp, wherein the main cooking parameters are as follows: the cooking liquor ratio is controlled to be 1: 4-5, the effective cooking time is 100-;
step 3, washing: performing four-stage countercurrent washing on the pulp treated in the step 2, wherein the residual alkali in the washed pulp is less than or equal to 150 mg/L;
and 4, screening: removing large slag from the slurry treated in the step 3 by using a knot remover, removing coarse non-steamed fiber bundle components by using a pressure screen, and removing silt and other dust brought by industrial hemp by using a sand remover;
and step 5, bleaching: single-stage bleaching the finished pulp treated in the step 4 by adopting hydrogen peroxide to obtain industrial hemp finished pulp, wherein the consumption of the hydrogen peroxide is 8-10kg/t pulp;
step 6, pulping: and (5) pulping the finished pulp obtained in the step (5) to obtain a finished product, wherein the pulping concentration is controlled to be 5-8%, and the pulping degree is less than or equal to 45 DEG SR.
2. The sulfate pulping process of industrial hemp according to claim 1, wherein the cooking temperature rise in step 2 is an early stage indirect temperature rise and a later stage direct temperature rise, and the temperature rise is divided into two times, the first temperature rise is carried out to 115-168 ℃, the small air release is carried out for 2-3 times, the second temperature rise is carried out to 160-168 ℃, the small air release is carried out for 5-10 times, and the temperature preservation time is not less than 50 min.
3. The kraft process for pulping industrial hemp according to claim 1, wherein after the completion of the cooking in step 2, the non-digested component in the resulting pulp is no more than 2.3%, and the kappa number is controlled to 15-50.
4. The kraft pulping process of industrial hemp according to claim 1, wherein the baume degree of black liquor after washing in step 3 is greater than or equal to 8.0 ° brede, the black liquor free alkali is greater than or equal to 5.0g/L, and the black liquor fiber content is less than or equal to 0.01 g/L.
5. The kraft pulping process of industrial hemp according to claim 1, wherein the ISO brightness of the bleached pulp in step 5 is 29-31% and the tear index is not less than 15.0mn.m2G, wet weight is more than or equal to 18g, and dust degree is less than or equal to 1.5mm2/m2。
6. The kraft process for pulping industrial hemp according to claim 1, wherein 1.0-2.0kg/t of the paper absorption height improver a and 0.1-0.2kg/t of the paper curing agent are added during pulping in step 6.
7. The kraft pulping process of industrial hemp according to claim 6, wherein the water absorption height improver A is a mixture of acrylonitrile graft copolymer starch and sodium alginate.
8. The kraft pulping process of industrial hemp according to claim 6, wherein the curing agent is p-hydroxybenzene sulfonic acid.
9. The kraft pulping process of industrial hemp according to claim 7, wherein the mixture of acrylonitrile graft copolymer starch and sodium alginate is added in a ratio of 3: 2.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112593434A (en) * | 2020-12-10 | 2021-04-02 | 岳阳林纸股份有限公司 | Sulfate pulping method for eucommia ulmoides |
| CN114622440A (en) * | 2022-03-17 | 2022-06-14 | 日照华泰纸业有限公司 | Production process of plastic-free paper for express packaging bags |
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| CN110438834A (en) * | 2019-08-08 | 2019-11-12 | 岳阳林纸股份有限公司 | A kind of camphorwood sulfate pulping technique |
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| CN1811055A (en) * | 2006-02-28 | 2006-08-02 | 华南理工大学 | Production process of bleached chemical pulp with hemp stalk core |
| CN101580970A (en) * | 2009-06-09 | 2009-11-18 | 山东海龙股份有限公司 | Preparation method for hemp pulp and prepared hemp pulp |
| CN102644212A (en) * | 2012-05-22 | 2012-08-22 | 云南聚恒科技有限公司 | Preparation method of industrial hemp full stalk pulp |
| CN102644211A (en) * | 2012-05-22 | 2012-08-22 | 云南聚恒科技有限公司 | Preparation method of industrial hemp full stalk bleaching chemical pulp |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112593434A (en) * | 2020-12-10 | 2021-04-02 | 岳阳林纸股份有限公司 | Sulfate pulping method for eucommia ulmoides |
| CN114622440A (en) * | 2022-03-17 | 2022-06-14 | 日照华泰纸业有限公司 | Production process of plastic-free paper for express packaging bags |
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| CN111962320B (en) | 2022-07-12 |
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