CN111826983A - Poplar rod core sulfate pulping process - Google Patents
Poplar rod core sulfate pulping process Download PDFInfo
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- CN111826983A CN111826983A CN202010508564.1A CN202010508564A CN111826983A CN 111826983 A CN111826983 A CN 111826983A CN 202010508564 A CN202010508564 A CN 202010508564A CN 111826983 A CN111826983 A CN 111826983A
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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
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- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21B—FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
- D21B1/00—Fibrous raw materials or their mechanical treatment
- D21B1/02—Pretreatment of the raw materials by chemical or physical means
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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
- D21C3/006—Pulping cellulose-containing materials with compounds not otherwise provided for
-
- 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
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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
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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
- 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
- D21C9/18—De-watering; Elimination of cooking or pulp-treating liquors from the pulp
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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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- 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 poplar rod core sulfate pulping process, which relates to the technical field of pulping and comprises the following preparation steps: the method comprises the steps of cutting and screening the remaining rod cores of the poplar rotary-cut board skin, then sending the cut and screened rod cores into a digester to be steamed and boiled, putting the boiled and boiled rod cores into washing equipment to be washed, then sending the washed and screened rod cores into a pressure screen to be bleached by adopting hydrogen peroxide, sending the bleached and bleached rod cores into a pulp storage tower to be stored, recycling the remaining poplar rod cores processed by the board skin, formulating a process flow according to the material characteristics of poplar, and being low in pulping cost, good in pulp quality and capable of completely meeting the requirements of high-grade paper production.
Description
Technical Field
The invention relates to the technical field of pulping, in particular to a poplar rod core sulfate pulping process.
Background
China is a country with serious shortage of wood resources, and the indexes of the primary wood pulp such as drainage performance, tensile strength, tearing index and the like are obviously superior to those of non-wood fiber, so that China needs to consume a large amount of wood pulp fiber every year. Because the domestic forest resources cannot support huge demand, a large amount of wood pulp and wood chips are imported every year, how to improve the self-sufficient rate of the wood pulp and reduce the dependence degree on the imported wood pulp is a major subject faced by the paper making industry in China. On the other hand, because the growth cycle of wood fiber raw materials, especially softwood, i.e. coniferous trees, is too long, the age of the trees is generally more than 15 years, so that large-scale pulping and papermaking enterprises and self-pulping production lines generally seek to produce virgin chemical wood pulp by using hardwood, i.e. hardwood, with shorter growth cycle in order to solve the problem of shortage of wood raw material resources.
The poplar is a fast-growing and high-yield tree species widely released in China, and has the characteristics of wide adaptability, long annual growth period, high growth speed and the like, the current poplar mainly comprises a poplar group, a populus euphratica group, a populus nigra group, a combined populus diversifolia group and the like, the poplar is mainly used for solid wood composite floors, core plates or bottom plates, and the main products comprise poplar laminated wood boards, full-poplar plywood, full-poplar bleached plywood and full-poplar furniture boards; after the poplar is processed into the veneer, a thin wood rod core is left, and the thin wood rod core can be used for papermaking after being cut into wood chips, so that each part of wood resource is fully saved.
Experiments prove that the residual rod core after the poplar is processed into the veneer is still a good pulping raw material, the average length of the fibers after pulping is about 0.72 mm, and the width of the fibersAbout 22 microns, the length-width ratio of the fiber is about 33, after pulping, the sheet strength is quickly improved, the breaking length is about 6.8Km under the condition of the beating degree of 40 DEG SR, and the tearing index is 7.0mN.m2About/g, the wood pulp can meet the production requirements of companies, but white rot fungi named polypore are available in the growth period of poplar, the white rot fungi corrode the wood from inside to outside, can decompose the main component cellulose in the wood, and has influence on pulping and bleaching of the wood, particularly, the poplar stick core is seriously corroded, the existing rotten wood can be removed in the conventional wood chip screening and chipping process, but the removing method belongs to a physical method and cannot completely remove the wood, the screened wood chips still have residual white rot fungi, and the pulping quality is still influenced, so that the pulping process is independently designed for the poplar stick core, the tension of wood raw materials can be relieved to a certain extent, limited wood resources are fully saved, the problem that the poplar stick core influences the pulp quality is solved, and no patent technology in the aspect is disclosed at present.
Disclosure of Invention
The invention aims to solve the problems, provides a poplar rod core sulfate pulping process, recycles poplar rod cores left after slab processing, formulates a process flow according to the material characteristics of poplar, has low pulping cost and good pulp quality, and can completely meet the requirements of high-grade paper production.
In order to realize the purpose, the invention adopts the technical scheme that:
a poplar rod core sulfate pulping process comprises the following preparation steps:
step A: chipping and pre-screening poplar wood chips, and controlling the length of the wood chips to be 10-55mm after screening; controlling the thickness of the wood chips to be 2-12 mm;
and B: feeding the poplar wood core wood chips prepared in the step A into a cooking pot, adding a traditional Chinese medicine mixed solution, controlling the heating rate in the cooking process, wherein the heating process is divided into 2 times, namely, first indirect heating and second direct heating, wherein the first heating is carried out to 130-140 ℃, then carrying out 2-3 times of operation of discharging non-condensable gas in the cooking pot, the second heating is carried out to 165-175 ℃, and carrying out 3-5 times of operation of discharging non-condensable gas in the cooking pot to prepare a standby slurry;
and C: b, placing the pulp prepared in the step B into washing equipment for washing, and extruding and dehydrating, wherein the content of residual alkali of the washed pulp is less than or equal to 150mg/l, the baume degree of black liquor is more than or equal to 8.0 Bee degrees, the content of free alkali of the black liquor is more than or equal to 5.0g/l, and the content of fiber of the black liquor is less than or equal to 0.01 g/l;
step D: c, feeding the pulp treated in the step C into a pressure sieve for screening to obtain good pulp;
step E: d, bleaching the good pulp obtained in the step D by adopting hydrogen peroxide, wherein the using amount of the hydrogen peroxide is 5-9kg/t pulp, the whiteness of the pulp is controlled to be 27-31 percent ISO, and the dust degree is less than or equal to 500mm2/kg；
Step F: and E, feeding the pulp treated in the step E into a pulp storage tower for storage.
Further, in the step A, according to the mass percentage, the qualification rate of the wood chips is controlled to be 70-98%, and the moisture content of the wood chips is controlled to be 10-50%.
Further, the specific preparation process of the traditional Chinese medicine mixed solution in the step B is as follows: mixing fructus forsythiae, radix sophorae flavescentis and galangal according to a mass ratio of 1: 1: 0.5-0.8, soaking in cold water for 5-10h, boiling with strong fire, continuously boiling with slow fire for 40-50min, filtering, decocting for three times, mixing the filtrates, and concentrating to obtain Chinese medicinal liquid.
Further, in the step B, the cooking solid-liquid ratio is controlled to be 1: 3.5-4.0 percent, the weight of the traditional Chinese medicine extraction mixed liquor is 3-5 percent of the weight of the wood chips; calculated by NaOH, the mass of alkali accounts for 18-22% of the mass of oven-dried wood chips.
Further, in the step B, the vulcanization degree is controlled to be 16-22%, and the pressure in the digester is controlled to be 0.70-0.90 Mpa.
Further, in the step B, the first temperature rise time is controlled to be 30-50min, and when the highest temperature is reached, the temperature is kept for 20-30 min.
Further, in the step B, the second temperature rise time is controlled to be 30-40min, and when the highest temperature is reached, the temperature is kept for 40-60 min.
Further, in the step D, the specific screening operation of the pressure screen is: the screen seam of the pressure screen is controlled to be 0.2-0.5mm, the pulp inlet pressure is controlled to be 3.0-7.0bar, the pressure difference of an inlet and an outlet is controlled to be 20-30kPa, the flow ratio of the slag pulp to the fine pulp is controlled to be 20-30%, and the operation load of the equipment is controlled to be 40-60%.
The invention has the beneficial effects that: (1) the invention provides a poplar rod core sulfate pulping process, which can recycle the residual poplar rod core after the veneer is processed, formulate a process flow according to the material characteristics of poplar, has low pulping cost and good pulp quality, and can completely meet the requirement of high-grade paper production;
(2) in the cooking process, non-condensable gas in the cooking pot is discharged for many times, so that the heat in the pot can be convected, the upper temperature, the middle temperature and the lower temperature are consistent, and the cooking uniformity is improved, so that the uniformity of the pulp quality is improved;
(3) the wood chips are pre-screened, but the specific white fungus of the poplar still remains on the wood chips and cannot be completely removed, the fungus is polypore berberidis, the lignin decomposition speed of the fungus is higher than the lignin decomposition speed of the fungus, the traditional Chinese medicine mixed liquor added in the invention comprises forsythia, sophora flavescens and galangal, wherein the phillyrin and matrine contained in the forsythia and the sophora flavescens can inhibit the activity of the white rot fungus, the growth cycle of the white rot fungus is delayed, the metabolism of the white rot fungus is slowed down, and the characteristic that the white rot fungus decomposes the lignin more quickly is added, the traditional Chinese medicine mixed liquor is added to be combined with the white rot fungus, so that the lignin content of the pulp obtained after cooking is reduced, the lignin removal speed during cooking is accelerated, the degradation of the cellulose and the hemicellulose is reduced, the cellulose is easier to swell, the fibrillation is easier during pulping, and the binding force of the fiber is increased; the galangal is added to harmonize the cold property of the forsythia and the sophora flavescens so as to enhance the activity of the effective components of the forsythia and the sophora flavescens and bring the drug property into play to a greater extent;
(4) the invention adopts sodium hydroxide as alkali to pulp, and since poplar is easy to be dipped and softened, the refined fiber is not as good as softwood fiber after pulp grinding, so the sodium hydroxide can effectively swell the fiber and obviously improve the flexibility and adaptability of the fiber; the invention adopts hydrogen peroxide as bleaching substance, which is used for keeping the whiteness of the pulp and preventing the pulp from yellowing caused by the reaction of sodium hydroxide and lignin.
Detailed Description
The present invention is described in detail below with reference to examples for better understanding of technical solutions of the present invention by those skilled in the art, and the description of the present invention is only exemplary and explanatory and should not be construed as limiting the scope of the present invention in any way.
Example 1:
a poplar rod core sulfate pulping process comprises the following preparation steps:
step A: chipping and pre-screening poplar wood chips, and controlling the length of the wood chips to be 10-50mm after screening; the thickness of the wood chips is controlled to be 5-12mm, the qualification rate of the wood chips is controlled to be 75% and the water content of the wood chips is 12.2% according to the mass percentage;
and B: and C, feeding the poplar wood rod core wood chips prepared in the step A into a cooking pot, and adding a traditional Chinese medicine mixed solution, wherein the cooking solid-to-liquid ratio is controlled to be 1: 3.7, adding the traditional Chinese medicine extraction mixed liquor, wherein the mass of the traditional Chinese medicine extraction mixed liquor accounts for 3% of the mass of the wood chips; taking NaOH as a reference, wherein the mass of alkali accounts for 21% of the mass of the oven-dried wood chips, controlling the heating rate in the cooking process, dividing the heating process into 2 times, carrying out first indirect heating and second direct heating, carrying out first heating to 130 ℃, controlling the heating time to be 40min, carrying out heat preservation for 30min when the highest temperature is reached, then carrying out 2 times of operation of discharging non-condensable gas in the cooking pot, carrying out second heating to 166 ℃, controlling the heating time to be 30min, carrying out heat preservation for 50min when the highest temperature is reached, carrying out 3 times of operation of discharging non-condensable gas in the cooking pot, controlling the vulcanization degree to be 16%, and controlling the pressure in the cooking pot to be 0.70MPa to prepare a standby slurry; the specific preparation process of the traditional Chinese medicine mixed solution is as follows: mixing fructus forsythiae, radix sophorae flavescentis and galangal according to a mass ratio of 1: 1: 0.8, mixing, placing into a medicine tank, soaking in cold water for 5h, then decocting with strong fire to boil, then changing to slow fire to continuously boil for 50min, filtering out the medicine juice, repeatedly decocting for three times, mixing the medicine juice filtered out for three times, and concentrating to obtain a traditional Chinese medicine mixed solution for later use;
and C: b, placing the pulp prepared in the step B into washing equipment for washing, and extruding and dehydrating, wherein the content of residual alkali in the washed pulp is 6.64mg/l, the baume degree of black liquor is 8.5 Bee degrees, the content of free alkali in the black liquor is 11.68g/l, and the content of fiber in the black liquor is 0.01 g/l;
step D: c, feeding the slurry treated in the step C into a pressure screen for screening, wherein the specific screening operation of the pressure screen is as follows: the screen seam of the pressure screen is controlled to be 0.2mm, the pulp inlet pressure is controlled to be 3.0bar, the pressure difference of an inlet and an outlet is controlled to be 20kPa, the flow ratio of the slag pulp to the good pulp is controlled to be 20 percent, and the operation load of equipment is controlled to be 40 percent, so that the good pulp is obtained;
step E: d, bleaching the good pulp obtained in the step D by adopting hydrogen peroxide, wherein the using amount of the hydrogen peroxide is 5kg/t pulp, the whiteness of the pulp is controlled to be 30.85 percent ISO, and the dust degree is 360mm2/kg；
Step F: and E, feeding the pulp treated in the step E into a pulp storage tower for storage.
Example 2:
a poplar rod core sulfate pulping process comprises the following preparation steps:
step A: chipping and pre-screening poplar wood chips, and controlling the length of the wood chips to be 15-45mm after screening; the thickness of the wood chips is controlled to be 5-10mm, the qualification rate of the wood chips is controlled to be 70% and the water content of the wood chips is 10% according to the mass percentage;
and B: and C, feeding the poplar wood rod core wood chips prepared in the step A into a cooking pot, and adding a traditional Chinese medicine mixed solution, wherein the cooking solid-to-liquid ratio is controlled to be 1: 3.5, adding the traditional Chinese medicine extraction mixed liquor, wherein the mass of the traditional Chinese medicine extraction mixed liquor accounts for 5% of the mass of the wood chips; taking NaOH as a reference, wherein the mass of alkali accounts for 18% of the mass of the oven-dried wood chips, controlling the heating rate in the cooking process, dividing the heating process into 2 times, carrying out first indirect heating and second direct heating, carrying out first heating to 135 ℃, controlling the heating time to be 30min, carrying out heat preservation for 20min when the highest temperature is reached, then carrying out 3 times of operation of discharging non-condensable gas in the cooking pot, carrying out second heating to 175 ℃, controlling the heating time to be 35min, carrying out heat preservation for 60min when the highest temperature is reached, carrying out 5 times of operation of discharging non-condensable gas in the cooking pot, controlling the vulcanization degree to be 20%, and controlling the pressure in the cooking pot to be 0.8Mpa to prepare a standby slurry; the specific preparation process of the traditional Chinese medicine mixed solution is as follows: mixing fructus forsythiae, radix sophorae flavescentis and galangal according to a mass ratio of 1: 1: 0.5, mixing, placing into a medicine tank, soaking in cold water for 10h, then decocting with strong fire to boil, then continuously boiling with slow fire for 40min, filtering out the decoction, repeatedly decocting for three times, mixing the three filtered decoctions, and concentrating to obtain a concentrated solution of traditional Chinese medicines;
and C: b, the pulp prepared in the step B is placed into washing equipment for washing, and is extruded and dehydrated, and after washing, the residual alkali content of the pulp is 5.48mg/l, the baume degree of black liquor is 0.6 Bee degrees, the free alkali content of the black liquor is 10.46g/l, and the fiber content of the black liquor is 0.005 g/l;
step D: c, feeding the slurry treated in the step C into a pressure screen for screening, wherein the specific screening operation of the pressure screen is as follows: the screen seam of the pressure screen is controlled to be 0.5mm, the pulp inlet pressure is controlled to be 5.0bar, the pressure difference of an inlet and an outlet is controlled to be 25kPa, the flow ratio of the slag pulp to the fine pulp is controlled to be 25 percent, the operation load of equipment is controlled to be 50 percent, and the fine pulp is obtained;
step E: d, bleaching the good pulp obtained in the step D by adopting hydrogen peroxide, wherein the using amount of the hydrogen peroxide is 9kg/t pulp, the whiteness of the pulp is controlled to be 31 percent ISO, and the dustiness is 495mm2/kg；
Step F: and E, feeding the pulp treated in the step E into a pulp storage tower for storage.
Example 3:
a poplar rod core sulfate pulping process comprises the following preparation steps:
step A: chipping and pre-screening poplar wood chips, and controlling the length of the wood chips to be 20-55mm after screening; the thickness of the wood chips is controlled to be 2-8mm, the qualification rate of the wood chips is controlled to be 98% and the water content of the wood chips is 50% according to the mass percentage;
and B: and C, feeding the poplar wood rod core wood chips prepared in the step A into a cooking pot, and adding a traditional Chinese medicine mixed solution, wherein the cooking solid-to-liquid ratio is controlled to be 1: 4.0, adding the traditional Chinese medicine extraction mixed liquor, wherein the mass of the traditional Chinese medicine extraction mixed liquor accounts for 4% of the mass of the wood chips; taking NaOH as a reference, wherein the mass of alkali accounts for 22% of the mass of the oven-dried wood chips, controlling the heating rate in the cooking process, dividing the heating process into 2 times, carrying out first indirect heating and second direct heating, carrying out first heating to 140 ℃, controlling the heating time to be 50min, carrying out heat preservation for 25min when the highest temperature is reached, then carrying out 2 times of operation of discharging non-condensable gas in the cooking pot, carrying out second heating to 165 ℃, controlling the heating time to be 40min, carrying out heat preservation for 40min when the highest temperature is reached, carrying out 3 times of operation of discharging non-condensable gas in the cooking pot, controlling the vulcanization degree to be 22%, and controlling the pressure in the cooking pot to be 0.90Mpa to prepare a standby slurry; the specific preparation process of the traditional Chinese medicine mixed solution is as follows: mixing fructus forsythiae, radix sophorae flavescentis and galangal according to a mass ratio of 1: 1: 0.7, mixing, placing into a medicine tank, soaking in cold water for 6h, then decocting with strong fire to boil, then continuously boiling with slow fire for 45min, filtering out the decoction, repeatedly decocting for three times, mixing the three filtered decoctions, and concentrating to obtain a concentrated solution of traditional Chinese medicines;
and C: b, the pulp prepared in the step B is placed into washing equipment for washing, and is extruded and dehydrated, and after washing, the residual alkali content of the pulp is 150mg/l, the baume degree of black liquor is 8.0 Bee degrees, the free alkali content of the black liquor is 5.0g/l, and the fiber content of the black liquor is 0.007 g/l;
step D: c, feeding the slurry treated in the step C into a pressure screen for screening, wherein the specific screening operation of the pressure screen is as follows: the screen seam of the pressure screen is controlled to be 0.3mm, the pulp inlet pressure is controlled to be 7.0bar, the pressure difference of an inlet and an outlet is controlled to be 30kPa, the flow ratio of the slag pulp to the fine pulp is controlled to be 30 percent, and the operation load of equipment is controlled to be 60 percent, so that the fine pulp is obtained;
step E: d, bleaching the good pulp obtained in the step D by adopting hydrogen peroxide, wherein the using amount of the hydrogen peroxide is 8kg/t pulp, the whiteness of the pulp is controlled to be 27 percent ISO, and the dust degree is 500mm2/kg；
Step F: and E, feeding the pulp treated in the step E into a pulp storage tower for storage.
Comparative example 1:
the difference between the comparative example 1 and the above example is that the traditional Chinese medicine mixed solution is not added in the pulping step B, and the rest is the same as the example 1.
Comparative example 2:
the difference between the comparative example 2 and the above example is that the traditional Chinese medicine mixed solution in the pulping step B is prepared by mixing fructus forsythiae and radix sophorae flavescentis according to the mass ratio of 1:1, and the rest is the same as that in the example 1.
The process parameters of the slurries prepared in the above examples and comparative examples are shown in table 1 below.
TABLE 1
As can be seen from the table 1, the invention not only promotes the lignin content in the pulp to be reduced, but also reduces the degradation of cellulose and hemicellulose, the cellulose is more easily swelled, the fibrillation is more easily realized during pulping, the bonding force of the fiber is increased, the tearing index and the burst index of the pulp are further improved, and the strength of the prepared pulp is greatly enhanced, so that the poplar rod core left after processing the veneer is recycled, the process flow is formulated according to the material characteristics of poplar, the pulping cost is low, the pulp quality is good, and the requirements of high-grade paper production can be completely met.
It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
The principles and embodiments of the present invention are explained herein using specific examples, which are presented only to assist in understanding the method and its core concepts of the present invention. The foregoing is only a preferred embodiment of the present invention, and it should be noted that there are objectively infinite specific structures due to the limited character expressions, and it will be apparent to those skilled in the art that a plurality of modifications, decorations or changes may be made without departing from the principle of the present invention, and the technical features described above may be combined in a suitable manner; such modifications, variations, combinations, or adaptations of the invention using its spirit and scope, as defined by the claims, may be directed to other uses and embodiments.
Claims (8)
1. The poplar rod core sulfate pulping process is characterized by comprising the following preparation steps of:
step A: chipping and pre-screening poplar wood chips, and controlling the length of the wood chips to be 10-55mm after screening; controlling the thickness of the wood chips to be 2-12 mm;
and B: feeding the poplar wood core wood chips prepared in the step A into a cooking pot, adding a traditional Chinese medicine mixed solution, controlling the heating rate in the cooking process, wherein the heating process is divided into 2 times, namely, first indirect heating and second direct heating, wherein the first heating is carried out to 130-140 ℃, then carrying out 2-3 times of operation of discharging non-condensable gas in the cooking pot, the second heating is carried out to 165-175 ℃, and carrying out 3-5 times of operation of discharging non-condensable gas in the cooking pot to prepare a standby slurry;
and C: b, placing the pulp prepared in the step B into washing equipment for washing, and extruding and dehydrating, wherein the content of residual alkali of the washed pulp is less than or equal to 150mg/l, the baume degree of black liquor is more than or equal to 8.0 Bee degrees, the content of free alkali of the black liquor is more than or equal to 5.0g/l, and the content of fiber of the black liquor is less than or equal to 0.01 g/l;
step D: c, feeding the pulp treated in the step C into a pressure sieve for screening to obtain good pulp;
step E: d, bleaching the good pulp obtained in the step D by adopting hydrogen peroxide, wherein the using amount of the hydrogen peroxide is 5-9kg/t pulp, the whiteness of the pulp is controlled to be 27-31 percent ISO, and the dust degree is less than or equal to 500mm2/kg；
Step F: and E, feeding the pulp treated in the step E into a pulp storage tower for storage.
2. The poplar rod core kraft pulping process of claim 1, wherein in step a, the pass rate of wood chips is controlled to 70-98% by mass percent, and the moisture content of the wood chips is 10-50%.
3. A method as claimed in claim 1Poplar woodThe rod core sulfate pulping process is characterized in that the specific preparation process of the traditional Chinese medicine mixed solution in the step B is as follows: mixing fructus forsythiae, radix sophorae flavescentis and galangal according to a mass ratio of 1: 1: 0.5-0.8, mixing, and placing into a medicinal potSoaking in cold water for 5-10 hr, decocting with strong fire, boiling with slow fire for 40-50min, filtering, decocting for three times, mixing the filtrates, and concentrating to obtain Chinese medicinal liquid.
4. The poplar rod core kraft pulping process of claim 1, wherein in step B, the cooking solid to liquid ratio is controlled to be 1: 3.5-4.0 percent, the weight of the traditional Chinese medicine extraction mixed liquor is 3-5 percent of the weight of the wood chips; calculated by NaOH, the mass of alkali accounts for 18-22% of the mass of oven-dried wood chips.
5. The poplar rod core kraft pulping process of claim 1, wherein in step B, the degree of vulcanization is controlled to 16-22% and the pressure in the digester is controlled to 0.70-0.90 Mpa.
6. The poplar rod core sulfate pulping process of claim 1, wherein in the step B, the first temperature rise time is controlled to be 30-50min, and the temperature is kept for 20-30min when the highest temperature is reached.
7. The poplar rod core kraft pulping process of claim 1, wherein in the step B, the second temperature rise time is controlled to be 30-40min, and the temperature is kept for 40-60min when the highest temperature is reached.
8. The poplar rod core kraft pulping process of claim 1, wherein in the step D, the specific screening operation of the pressure screen is: the screen seam of the pressure screen is controlled to be 0.2-0.5mm, the pulp inlet pressure is controlled to be 3.0-7.0bar, the pressure difference of an inlet and an outlet is controlled to be 20-30kPa, the flow ratio of the slag pulp to the fine pulp is controlled to be 20-30%, and the operation load of the equipment is controlled to be 40-60%.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010508564.1A CN111826983A (en) | 2020-06-06 | 2020-06-06 | Poplar rod core sulfate pulping process |
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| CN202010508564.1A CN111826983A (en) | 2020-06-06 | 2020-06-06 | Poplar rod core sulfate pulping process |
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Cited By (2)
| 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 |
| CN113930991A (en) * | 2021-11-01 | 2022-01-14 | 岳阳林纸股份有限公司 | Cortex phellodendri pulping process |
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| CN103321080A (en) * | 2013-07-17 | 2013-09-25 | 齐鲁工业大学 | ECF bleaching technology of fast growing poplar by sulfate pulp bio-chemical method |
| CN104705216A (en) * | 2015-03-17 | 2015-06-17 | 安徽强英鸭业集团有限公司 | Breed duck egg disinfection soak solution and preparation method thereof |
| CN109235103A (en) * | 2018-09-21 | 2019-01-18 | 岳阳林纸股份有限公司 | A kind of pine sheet and wealthy miscellaneous mixed sulfate chemical pulping process |
| 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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| CN102535237A (en) * | 2011-12-27 | 2012-07-04 | 北京晨峰投资控股有限公司 | Sulfate pulping method of broadleaf wood compressed wood chip |
| CN103321080A (en) * | 2013-07-17 | 2013-09-25 | 齐鲁工业大学 | ECF bleaching technology of fast growing poplar by sulfate pulp bio-chemical method |
| CN104705216A (en) * | 2015-03-17 | 2015-06-17 | 安徽强英鸭业集团有限公司 | Breed duck egg disinfection soak solution and preparation method thereof |
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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 |
| CN113930991A (en) * | 2021-11-01 | 2022-01-14 | 岳阳林纸股份有限公司 | Cortex phellodendri pulping process |
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