CN103266519A - Preparation method of bleached straw pulp - Google Patents
Preparation method of bleached straw pulp Download PDFInfo
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- CN103266519A CN103266519A CN2013101774912A CN201310177491A CN103266519A CN 103266519 A CN103266519 A CN 103266519A CN 2013101774912 A CN2013101774912 A CN 2013101774912A CN 201310177491 A CN201310177491 A CN 201310177491A CN 103266519 A CN103266519 A CN 103266519A
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- 239000010902 straw Substances 0.000 title claims abstract description 82
- 238000002360 preparation method Methods 0.000 title claims abstract description 29
- 238000004061 bleaching Methods 0.000 claims abstract description 63
- 238000010411 cooking Methods 0.000 claims abstract description 53
- 239000002994 raw material Substances 0.000 claims abstract description 51
- 238000000034 method Methods 0.000 claims abstract description 40
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 26
- 239000001301 oxygen Substances 0.000 claims abstract description 26
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 26
- 239000003513 alkali Substances 0.000 claims abstract description 21
- WQYVRQLZKVEZGA-UHFFFAOYSA-N hypochlorite Chemical compound Cl[O-] WQYVRQLZKVEZGA-UHFFFAOYSA-N 0.000 claims abstract description 18
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 48
- 244000025254 Cannabis sativa Species 0.000 claims description 38
- 238000009835 boiling Methods 0.000 claims description 29
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical group [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 claims description 28
- 241000209140 Triticum Species 0.000 claims description 17
- 235000021307 Triticum Nutrition 0.000 claims description 17
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims description 14
- 239000000460 chlorine Substances 0.000 claims description 14
- 229910052801 chlorine Inorganic materials 0.000 claims description 14
- 229910052943 magnesium sulfate Inorganic materials 0.000 claims description 14
- 235000019341 magnesium sulphate Nutrition 0.000 claims description 14
- 239000012752 auxiliary agent Substances 0.000 claims description 13
- 239000002002 slurry Substances 0.000 claims description 13
- 230000029087 digestion Effects 0.000 claims description 9
- 238000012216 screening Methods 0.000 abstract description 6
- 239000003344 environmental pollutant Substances 0.000 abstract description 3
- 231100000719 pollutant Toxicity 0.000 abstract description 3
- 238000005406 washing Methods 0.000 abstract description 3
- 239000007844 bleaching agent Substances 0.000 abstract description 2
- 238000004537 pulping Methods 0.000 description 9
- 229920001131 Pulp (paper) Polymers 0.000 description 7
- 238000006243 chemical reaction Methods 0.000 description 6
- 239000000203 mixture Substances 0.000 description 6
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 239000011734 sodium Substances 0.000 description 4
- GEHJYWRUCIMESM-UHFFFAOYSA-L sodium sulfite Chemical compound [Na+].[Na+].[O-]S([O-])=O GEHJYWRUCIMESM-UHFFFAOYSA-L 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 239000007864 aqueous solution Substances 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 230000018044 dehydration Effects 0.000 description 3
- 238000006297 dehydration reaction Methods 0.000 description 3
- 239000000835 fiber Substances 0.000 description 3
- 229920005610 lignin Polymers 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- 229910052708 sodium Inorganic materials 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 239000000428 dust Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000000284 extract Substances 0.000 description 2
- 238000001125 extrusion Methods 0.000 description 2
- 239000000446 fuel Substances 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 235000010265 sodium sulphite Nutrition 0.000 description 2
- 239000000725 suspension Substances 0.000 description 2
- 230000003197 catalytic effect Effects 0.000 description 1
- 229920002678 cellulose Polymers 0.000 description 1
- 239000001913 cellulose Substances 0.000 description 1
- 238000005660 chlorination reaction Methods 0.000 description 1
- 238000004040 coloring Methods 0.000 description 1
- 238000002845 discoloration Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 239000004459 forage Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- ZLNQQNXFFQJAID-UHFFFAOYSA-L magnesium carbonate Chemical compound [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 description 1
- 239000001095 magnesium carbonate Substances 0.000 description 1
- 229910000021 magnesium carbonate Inorganic materials 0.000 description 1
- 235000014380 magnesium carbonate Nutrition 0.000 description 1
- VTHJTEIRLNZDEV-UHFFFAOYSA-L magnesium dihydroxide Chemical compound [OH-].[OH-].[Mg+2] VTHJTEIRLNZDEV-UHFFFAOYSA-L 0.000 description 1
- 239000000347 magnesium hydroxide Substances 0.000 description 1
- 229910001862 magnesium hydroxide Inorganic materials 0.000 description 1
- 235000012254 magnesium hydroxide Nutrition 0.000 description 1
- 159000000003 magnesium salts Chemical class 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 238000002161 passivation Methods 0.000 description 1
- 238000004076 pulp bleaching Methods 0.000 description 1
- 229910052938 sodium sulfate Inorganic materials 0.000 description 1
- 235000011152 sodium sulphate Nutrition 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
Images
Abstract
The invention discloses a preparation method of bleached straw pulp, which comprises the following steps: (1) adding a straw raw material and cooking liquor into cooking equipment in a weight ratio of 1:3-1:6, evenly mixing, and closing the cooking equipment, wherein the cooking liquor contains alkali; (2) introducing oxygen into the closed cooking equipment while keeping the oxygen pressure in the cooking equipment at 0.3-1.0 MPa, and cooking the straw raw material in the cooking liquor at 90-130 DEG C for 30-240 minutes; (3) washing and screening the pulp after finishing the cooking process to obtain fine pulp; and (4) bleaching the fine pulp in the step (3) with hypochlorite. The hypochlorite can bleach the straw pulp to the whiteness of higher than 78% in one bleaching process, thereby reducing two bleaching processes as compared with the CEH bleaching process adopted by a common alkaline method; and thus, the operating cost is lowered by 2/3, and the bleaching pollutant burden is lowered by more than 60%.
Description
Technical field
The present invention relates to field of papermaking, relate in particular to a kind of preparation method of paper grade (stock) bleaching straw pulp.
Background technology
Be that raw material is made paper pulp and once dominated China's pulp and paper industry about 40 years with agricultural crop straw (particularly straw or wheat straw).Over surplus in the of nearly 10 year, along with environmental pollution improvement's level requires more and more higher, the inadequate natural endowment that grass as raw material exists causes the level of its cleaner production obviously not as good as wood raw material, and the pulping process inefficiency also allows people that the problem that grass as raw material slurrying exists is quite felt thorny in addition.Therefore, problems such as the low yield that exists in careless class pulping process, high flow rate, high pollution have seriously limited the development of careless class pulp industry.
Along with The development in society and economy, people constantly increase the paper products consumption demand and the paper products quality are proposed higher requirement, adopted careless class high yield cooking fairly simple, extensive style in the past, particularly the straw pulp of machinery pulping acquisition is low because of quality, and fertile paper product also has been subjected to considerable restraint.In order to promote straw pulp quality and added value, adopt the chemical pulping method, but the rate of obtaining of straw pulp is not high again.Therefore, seek a kind of clean type pulping process that can improve careless class effects on slurry making and promote the straw pulp quality and just seem particularly important.
Summary of the invention
The object of the present invention is to provide and a kind ofly can obviously improve careless class pulp yield, improve the bleaching straw pulp quality, significantly reduce the pulping process of pollutant burden.
The invention provides a kind of preparation method of bleaching straw pulp, this method comprises following operation:
(1) be added in digesting apparatus with the weight ratio of 1:3-1:6 grass as raw material and cooking liquor and mix, then that digesting apparatus is airtight, wherein, contain alkali in the described cooking liquor;
(2) aerating oxygen makes in the digesting apparatus oxygen press and remains 0.3-1.0MPa in the described airtight digesting apparatus, with described grass as raw material with described cooking liquor at 90-130 ℃ of following boiling 30-240 minute;
(3) will finish the slurry that obtains behind the digestion process and wash and screen, obtain screened stock;
(4) screened stock in the described operation (3) is bleached with hypochlorite.
Alternatively, among the preparation method according to bleaching straw pulp of the present invention, in the operation (4), the concentration of described screened stock is 3-12%, and described bleaching process carried out under 35-60 ℃ 30-90 minute.
Alternatively, among the preparation method according to bleaching straw pulp of the present invention, in the described bleaching process, the effective chlorine consumption is 2-4%.
Alternatively, among the preparation method according to bleaching straw pulp of the present invention, between described operation (1) and operation (2), further comprise the operation of described grass as raw material being carried out pre-boiling with described cooking liquor.
Alternatively, among the preparation method according to bleaching straw pulp of the present invention, the time of described pre-boiling is 10-60 minute.
Alternatively, among the preparation method of bleaching straw pulp of the present invention, described pre-stewing temperature is 90-130 ℃.
Alternatively, among the preparation method according to bleaching straw pulp of the present invention, described cooking liquor also contains the protection auxiliary agent, and wherein, the consumption of alkali is the 13%-22% of grass as raw material weight, and the consumption of protection auxiliary agent is the 0.1%-2.0% of grass as raw material weight.
Alternatively, among the preparation method according to bleaching straw pulp of the present invention, described alkali is NaOH.
Alternatively, among the preparation method according to bleaching straw pulp of the present invention, described protection auxiliary agent is magnesium sulfate.
Alternatively, among the preparation method according to bleaching straw pulp of the present invention, described forage raw material is straw or wheat straw.
Compared with prior art, the preparation method's of bleaching straw pulp of the present invention beneficial effect is:
(1) the lignin efficient that removes of the straw pulp of oxygen alkali cooking acquisition obviously improves, and Kappa number is lower than 12, and is highly beneficial to following bleaching for the soft straw pulp, with one section hypochlorite, just the whiteness of straw pulp can be floated to more than 78%.Bleaching process than the common chlorination of adopting of common alkaline straw-pulp, alkali treatment and hypochlorite bleaching combination (CEH) has lacked two sections driftages, operating cost reduces by 2/3, pollutant burden in the bleaching process reduces more than 60%, can significantly promote the production that cleans of straw pulp;
(2) yield of the bleaching straw pulp of Huo Deing exceeds traditional alkaline process bleaching straw pulp 5-10%, and pulp viscosity has improved 110-180mL/g, and the comprehensive physical strength of bleached pulp increases 15-20%, and pulp quality improves significantly.
Description of drawings
By reading hereinafter detailed description of the preferred embodiment, various other advantage and benefits will become cheer and bright for those of ordinary skills.Accompanying drawing only is used for the purpose of preferred embodiment is shown, and does not think limitation of the present invention.In the accompanying drawings:
Fig. 1 is the preparation method's of bleaching straw pulp of the present invention schematic flow sheet.
The specific embodiment
The invention will be further described below in conjunction with accompanying drawing and concrete embodiment.
Fig. 1 illustrates the preparation method's of bleaching straw pulp of the present invention schematic flow sheet.As shown in Figure 1, at first be added in digesting apparatus with the weight ratio of 1:3-1:6 grass as raw material and cooking liquor and mix, then that digesting apparatus is airtight, wherein, contain alkali in the described cooking liquor.Before being delivered to described grass as raw material in the digesting apparatus, described grass as raw material is prescinded, so that grass as raw material is more thorough with contacting of cooking liquor, reaction is more comprehensively.The grass as raw material that prescinds is carried out dust removal process, wash then, to remove foreign material wherein, dewater after the washing.Through above-mentioned processing, dust and the foreign material having avoided bringing into because of grass as raw material self influence slurrying efficient.Used grass as raw material is straw or wheat straw among the present invention.
The cooking liquor that contains alkali used among the present invention also contains the protection auxiliary agent, and wherein, the consumption of alkali is the 13%-22% of grass as raw material weight, and the consumption of protection auxiliary agent is the 0.1%-2.0% of grass as raw material weight.When the grass as raw material moisture-free, the consumption of described alkali and protection auxiliary agent is the benchmark metering with the weight of grass as raw material; When grass as raw material was moisture, the consumption of described alkali and protection auxiliary agent was the benchmark metering with the oven dry weight of grass as raw material.
Used alkali mainly is NaOH in the cooking liquor, can also be the mixture of NaOH and vulcanized sodium or sodium sulfite.When using said mixture, based on NaOH, be auxilliary with vulcanized sodium or sodium sulfite, the consumption of mixture is in NaOH.The cellulose of grass as raw material is destroyed in the digestion process, has added the protection auxiliary agent in cooking liquor.The used protection auxiliary agent of the present invention is magnesium sulfate, because the metal ion that can play catalytic action that magnesium salts contains in can passivation paper pulp plays the cellulosic effect of protection.Be understandable that described protection auxiliary agent can also be the compound of magnesium sulfate, for example the compound of the compound of magnesium sulfate and magnesium carbonate or magnesium sulfate and magnesium hydroxide.With before described grass as raw material mixes, described cooking liquor can be preheated to 80-90 ℃.
After in digesting apparatus, being ready to grass as raw material and cooking liquor, begin to carry out oxygen alkali cooking namely, aerating oxygen makes in the digesting apparatus oxygen press and remains 0.3-1.0MPa in the airtight digesting apparatus, with described grass as raw material with described cooking liquor at 90-130 ℃ of following boiling 30-240 minute.
Before grass as raw material is carried out oxygen alkali cooking, can also carry out pre-boiling to it, to improve slurrying efficient, shorten follow-up oxygen alkali cooking required time.Described pre-boiling is exactly before aerating oxygen in airtight digesting apparatus, and grass as raw material is carried out boiling with cooking liquor.At this moment, grass as raw material is with cooking liquor reacts under the situation of oxygen not having, the most of stripping of the lignin in the grass as raw material.Among the present invention, the time of described pre-boiling is preferably 10-60 minute, and pre-stewing temperature is preferably 90-130 ℃.
After oxygen alkali cooking finishes, wash and Screening Treatment after the gained slurry spurted digesting apparatus, obtain screened stock.Described screened stock sent in the bleaching tower that contains hypochlorite bleach, obtain bleaching straw pulp.The ratio of the oven dry weight of screened stock and pulping raw material oven dry weight is screened yield.Weight when wherein, oven dry weight refers to the material moisture-free.
Among the present invention, described bleaching process has carried out under 35-60 ℃ 30-90 minute, and the concentration of described screened stock is 3%-12%, and the effective chlorine consumption is 2-4%.Wherein, described screened stock concentration refers to the percentage of fiber oven dry weight and suspension weight in the pulp suspension.The effective chlorine consumption refers to that association with pulp bleaching arrives the percentage of the needed effective chlorine weight of certain whiteness and paper pulp oven dry weight, and effective chlorine refers to can react with residual lignin in the brown stock and other coloring matters in the chlorine bleaches, have that a part of chlorine of discoloration, represent with the size of oxidability.
When the slurry that boiling is obtained spurts, when if slurry temperature is lower than 100 ℃, directly spurt, if when slurry temperature is higher than 100 ℃, then pumps in the digesting apparatus and spurt again after portion temperature and the lower black liquor of concentration make slurry temperature be down to below 100 ℃.The black liquor that extracts in the described slurry processing procedure is sent into chemical recovery system after silica removal is handled; The screening reject that produces can return digesting apparatus again with the boiling of straw section, but also acts as a fuel behind the extrusion dehydration.So-called screening reject refers in the chemical pulping process that the impurity such as wooden unit, ring, grass section and coarse fiber bundle that the part that exists in the slurry that boiling obtains is not steamed solution sift out it with pressurized screen or vibrating screen usually.
The optional factor of bleaching straw pulp preparation method that proposes according to the present invention is more, can design various embodiments, so specific embodiment is only as the exemplary illustration of specific implementation of the present invention, and does not constitute limitation of the scope of the invention.For concrete description the present invention, select following examples to carry out exemplary illustration.
Embodiment 1
Straw is prescinded and carry out dedusting, then it is washed, remove foreign material wherein, dewater after washing finishes.Straw after the dehydration is sent in the digesting apparatus, added the cooking liquor that is preheated to 90 ℃ simultaneously and mix with it, the weight ratio of described straw and described cooking liquor is 1:3.5.Described cooking liquor is the aqueous solution of NaOH and magnesium sulfate, and the consumption of NaOH is 15% of straw weight, and the consumption of magnesium sulfate is 2% of straw weight.After charging finishes that digesting apparatus is airtight, to aerating oxygen wherein oxygen is pressed and remain 0.5MPa.Hot digestion equipment uses cooking liquor 130 ℃ of following boilings 30 minutes straw.After boiling finishes, pump into that temperature and the lower black liquor of concentration are down under the boiling point the interior temperature of boiling vessel system in, then the gained slurry is spurted, wash and Screening Treatment spurting the slurry that, obtain screened stock.The black liquor that extracts in the processing procedure send chemical recovery system after silica removal is handled; Screening reject can return digesting apparatus again with the boiling of straw section, but also acts as a fuel behind the extrusion dehydration.Gained screened stock concentration is adjusted into 3%, sends in the bleaching tower that contains hypochlorite, bleached 30 minutes down at 60 ℃.In this bleaching process, effective chlorine consumption 4%.Bleaching is washed paper pulp by the code requirement wash degree after finishing.
In the present embodiment, every index result of obtained screened stock is: screened yield 56.5%, Kappa number 9.0, whiteness 52%ISO, viscosity 890mL/g; Every index result of the bleaching straw pulp that obtains after the process bleaching is: to raw material yield 49.6%, whiteness 78.2%ISO, viscosity 730mL/g, and standard sheet pulp tensile index 61Nm/g, burst index 3.8kPam
2/ g, tear index 5.9mNm
2/ g.
Wherein, the raw material yield is referred to the percentage of bleaching straw pulp oven dry weight and pulping raw material oven dry weight because screened stock can loss part fiber in bleaching process, the oven dry weight of the bleaching straw pulp that finally obtains less than bleaching before the oven dry weight of screened stock; The sheet pulp that the standard sheet pulp obtains after referring to according to the concerned countries standard paper pulp be handled.
Embodiment 2
Repeat embodiment 1, the partial reaction parameter is done following adjustment: the weight ratio of straw and cooking liquor is 1:6, cooking liquor is the aqueous solution of NaOH, vulcanized sodium and magnesium sulfate, wherein the consumption of NaOH and vulcanized sodium be straw weight 20%, the magnesium sulfate consumption is 0.1% of straw weight, oxygen pressure in the digesting apparatus remains 1MPa, boiling temperature is 90 ℃, and digestion time is 240 minutes.Boiling is directly spurted slurry after finishing.Bleaching process has carried out under 35 ℃ 90 minutes, and the concentration of screened stock is 12%, effective chlorine consumption 2%.
In the present embodiment, every index result of obtained screened stock is: screened yield 52.3%, Kappa number 6.7, whiteness 62%ISO, viscosity 810mL/g; Every index result of the bleaching straw pulp that obtains after the process bleaching is: to raw material yield 46.0%, whiteness 81.1%ISO, viscosity 730mL/g, and standard sheet pulp tensile index 63Nm/g, burst index 3.9kPam
2/ g, tear index 6.1mNm
2/ g.
Embodiment 3
Repeat embodiment 1, the partial reaction parameter is done following adjustment: the weight ratio of described straw and cooking liquor is 1:4.5, wherein the consumption of NaOH be straw weight 18%, the magnesium sulfate consumption is 0.75% of straw weight.Charging is airtight with digesting apparatus after finishing, and described straw is descended pre-boilings 60 minutes with described cooking liquor at 100 ℃.After finishing pre-boiling, aerating oxygen makes in the digesting apparatus oxygen press and remains 0.3MPa in the digesting apparatus.Hot digestion equipment uses cooking liquor 100 ℃ of following boilings 120 minutes straw.Bleaching process has carried out under 45 ℃ 50 minutes, and the concentration of screened stock is 10%, effective chlorine consumption 2.5%.
In the present embodiment, every index result of obtained screened stock is: screened yield 55%, Kappa number 7.6, whiteness 57%ISO, viscosity 860mL/g; Every index result of the bleaching straw pulp that obtains after the process bleaching is: to raw material yield 48.5%, whiteness 80.9%ISO, viscosity 740mL/g, and standard sheet pulp tensile index 67Nm/g, burst index 4.5kPam
2/ g, tear index 6.2mNm
2/ g.
Embodiment 4
Repeat embodiment 1, the partial reaction parameter is done following adjustment: used grass as raw material is wheat straw, the weight ratio of wheat straw and cooking liquor is 1:5, in the cooking liquor consumption of NaOH be wheat straw weight 17%, the consumption of magnesium sulfate is 1% of wheat straw weight, oxygen pressure in the digesting apparatus remains 0.8MPa, boiling temperature is 130 ℃, and digestion time is 30 minutes.Bleaching process has carried out under 40 ℃ 75 minutes, and the concentration of screened stock is 5%, effective chlorine consumption 3.5%.
In the present embodiment, every index result of obtained screened stock is: screened yield 57.3%, Kappa number 9.2, whiteness 53%ISO, viscosity 900mL/g; Every index result of the bleaching straw pulp that obtains after the process bleaching is: to raw material yield 50.1%, whiteness 79.4%ISO, viscosity 780mL/g, and standard sheet pulp tensile index 68Nm/g, burst index 4.9kPam
2/ g, tear index.
Embodiment 5
Repeat embodiment 4, the partial reaction parameter is done following adjustment: the weight ratio of wheat straw and cooking liquor is 1:3, wherein the consumption of NaOH be wheat straw weight 22%, the magnesium sulfate consumption is 1.5% of wheat straw weight, oxygen pressure in the digesting apparatus remains 1.0MPa, boiling temperature is 100 ℃, and digestion time is 240 minutes.Bleaching process has carried out under 35 ℃ 60 minutes, and the concentration of screened stock is 8%, effective chlorine consumption 2%.
In the present embodiment, every index result of obtained screened stock is: screened yield 52.7%, Kappa number 6.8, whiteness 62.4%ISO, viscosity 830mL/g; Every index result of the bleaching straw pulp that obtains after the process bleaching is: to raw material yield 46.0%, whiteness 81.1%ISO, viscosity 730mL/g, and standard sheet pulp tensile index 68Nm/g, burst index 4.5kPam
2/ g, tear index 7.3mNm
2/ g.
Embodiment 6
Repeat embodiment 3, the partial reaction parameter is done following adjustment: used grass as raw material is wheat straw, and the weight ratio of wheat straw and cooking liquor is 1:3.Used cooking liquor is the aqueous solution of NaOH in the pre-boiling, and the consumption of NaOH is 18% of wheat straw weight.Pre-stewing temperature is 130 ℃, and pre-digestion time is 20 minutes.After pre-boiling finished, the temperature and the lower black liquor of concentration that pump into system's reuse in the digesting apparatus were lowered the temperature, when temperature is down to 115 ℃, to the digesting apparatus aerating oxygen its inner oxygen is pressed and remains 0.6MPa, under 115 ℃ with straw cooking 120 minutes.The weight ratio of the black liquor that described wheat straw and the described temperature that pumps into and concentration are lower is 1:0.3.Be dissolved with the NaOH of wheat straw weight 4% and the magnesium sulfate of wheat straw weight 0.25% in the lower black liquor of described temperature and concentration.Bleaching process has carried out under 40 ℃ 50 minutes, and the concentration of screened stock is 4%, effective chlorine consumption 2.25%.
In the present embodiment, every index result of obtained screened stock is: screened yield 53.9%, Kappa number 7.2, whiteness 61.8%ISO, viscosity 890mL/g; Every index result of the bleaching straw pulp that obtains after the process bleaching is: to raw material yield 48.1%, whiteness 81.3%ISO, viscosity 750mL/g, the standard sheet pulp is opened tensile index 70Nm/g, burst index 4.7kPam
2/ g, tear index 7.1mNm
2/ g.
The preparation method of bleaching straw pulp of the present invention, by grass as raw material being carried out one step of oxygen alkali cooking operation or pre-boiling and two step of oxygen alkali cooking operation, can obtain the yield height, the good quality paper pulp that hardness is lower, make follow-up bleaching efficiency significantly promote, only need one section hypochlorite bleaching can obtain whiteness and surpass 78% paper pulp, saved production cost, improved the efficient that cleans production.
It should be noted that the present invention will be described rather than limit the invention for above-described embodiment, and those skilled in the art can design alternative embodiment under the situation of the scope that does not break away from claims.In the claims, any reference symbol between bracket should be configured to limitations on claims.Word " comprises " not to be got rid of existence and is not listed in element or step in the claim.
Claims (10)
1. the preparation method of a bleaching straw pulp, this method comprises following operation:
(1) be added in digesting apparatus with the weight ratio of 1:3-1:6 grass as raw material and cooking liquor and mix, then that digesting apparatus is airtight, wherein, contain alkali in the described cooking liquor;
(2) aerating oxygen makes in the digesting apparatus oxygen press and remains 0.3-1.0MPa in the described airtight digesting apparatus, with described grass as raw material with described cooking liquor at 90-130 ℃ of following boiling 30-240 minute;
(3) will finish the slurry that obtains behind the digestion process and wash and screen, obtain screened stock;
(4) screened stock in the described operation (3) is bleached with hypochlorite.
2. preparation method according to claim 1 is characterized in that: in the operation (4), the concentration of described screened stock is 3-12%, and described bleaching process carried out under 35-60 ℃ 30-90 minute.
3. preparation method according to claim 2, it is characterized in that: in the described bleaching process, the effective chlorine consumption is 2-4%.
4. according to each described preparation method among the claim 1-3, it is characterized in that: between described operation (1) and operation (2), further comprise the operation of described grass as raw material being carried out pre-boiling with described cooking liquor.
5. preparation method according to claim 4 is characterized in that: the time of pre-boiling is 10-60 minute.
6. preparation method according to claim 5, it is characterized in that: described pre-stewing temperature is 90-130 ℃.
7. according to each described preparation method among the claim 1-3; it is characterized in that: described cooking liquor contains the protection auxiliary agent further; wherein, the consumption of alkali is the 13%-22% of grass as raw material weight, and the consumption of protection auxiliary agent is the 0.1%-2.0% of grass as raw material weight.
8. according to each described preparation method among the claim 1-3, it is characterized in that: described alkali is NaOH.
9. according to each described preparation method among the claim 1-3, it is characterized in that: described protection auxiliary agent is magnesium sulfate.
10. according to each described preparation method among the claim 1-3, it is characterized in that: described grass as raw material is straw or wheat straw.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106108104A (en) * | 2015-12-18 | 2016-11-16 | 广东中烟工业有限责任公司 | A kind of reduce the processing method of content of lignin in cabo |
| CN106661842A (en) * | 2014-05-20 | 2017-05-10 | 佐治亚-太平洋消费产品有限合伙公司 | Bleaching and shive reduction process for non-wood fibers |
| US10640899B2 (en) | 2014-05-20 | 2020-05-05 | Gpcp Ip Holdings Llc | Bleaching and shive reduction process for non-wood fibers |
| US10844538B2 (en) | 2014-05-20 | 2020-11-24 | Gpcp Ip Holdings Llc | Bleaching and shive reduction process for non-wood fibers |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106661842A (en) * | 2014-05-20 | 2017-05-10 | 佐治亚-太平洋消费产品有限合伙公司 | Bleaching and shive reduction process for non-wood fibers |
| CN110359312A (en) * | 2014-05-20 | 2019-10-22 | Gpcp知识产权控股有限责任公司 | The bleaching and clast reduction method of non-wood-fiber |
| US10640899B2 (en) | 2014-05-20 | 2020-05-05 | Gpcp Ip Holdings Llc | Bleaching and shive reduction process for non-wood fibers |
| US10711399B2 (en) | 2014-05-20 | 2020-07-14 | Gpcp Ip Holdings Llc | Bleaching and shive reduction process for non-wood fibers |
| US10844538B2 (en) | 2014-05-20 | 2020-11-24 | Gpcp Ip Holdings Llc | Bleaching and shive reduction process for non-wood fibers |
| CN106108104A (en) * | 2015-12-18 | 2016-11-16 | 广东中烟工业有限责任公司 | A kind of reduce the processing method of content of lignin in cabo |
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