CN102242514A - Paper pulp high density bleaching method - Google Patents
Paper pulp high density bleaching method Download PDFInfo
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- CN102242514A CN102242514A CN2011101494255A CN201110149425A CN102242514A CN 102242514 A CN102242514 A CN 102242514A CN 2011101494255 A CN2011101494255 A CN 2011101494255A CN 201110149425 A CN201110149425 A CN 201110149425A CN 102242514 A CN102242514 A CN 102242514A
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Abstract
The invention provides a paper pulp high density bleaching method which comprises the following steps: condensing unleached paper pulp after washing and carrying out extruding dehydration on the condensed paper pulp with a double-screw extruder so as to obtain a high density slurry; pumping mixed liquor of hydrogen peroxide and a bleaching auxiliary agent into the high density slurry to obtain a mixture of materials and reagents; inputting the mixture into a high density bleaching warehouse with feeding spirals and carrying out bleaching at elevated temperature and pressure so as to obtain a bleached slurry; directly inputting the bleached slurry into a high density pulping machine with feeding spirals without washing, and adding sodium hydrosulphite into the high density pulping machine with metering screws during the process of feeding so as to obtain a mixture of materials and reagents; inputting the mixture into the high density bleaching warehouse with feeding spirals after the mixture comes out from the high density pulping machine, discharging the mixture after bleaching at elevated temperature and carrying out fiber dispersion and washing to obtain high beating degree bleaching paper pulp. According to the invention, slurries are delivered by spirals and concentration of the delivered slurries is high, which enables energy consumption in delivery to be reduced, heat energy consumption in the chemical reaction of bleaching to be effectively reduced and economic benefits to be increased.
Description
Technical field
The present invention relates to paper pulp bleaching process, be specifically related to a kind of paper pulp high density bleaching method.
Background technology
Pulping and paper-making is a heavy polluted industry, be to reduce environmental pollution, improve pulp bleaching efficiency, the pulping bleaching technology in dense (＞7%), high dense (＞25%) bleaching technology development.Experimental results show that improving association with pulp bleaching concentration can improve bleaching efficiency, reduces the bleaching chemical consumption, reduce environmental pollution; Especially under situation about being becoming tight coal resources day, improve bleaching concentration and can effectively reduce thermal energy consumption, increase economic efficiency.
Pulp density is higher than at 7% o'clock, minimizing along with flowing carrier water, slurry changes the pseudo plastic state into by the suspension state, formation has the network packet and the body of higher-strength, in this bag and body, interweave between fiber and the fiber closely, show bigger internal friction when mobile mutual, the flow behavior of scattering and disappearing, pumping is very difficult.Along with the discovery and the middle underflow pump development of technology of paper pulp turbulent flow phenomenon, paper pulp medium consistency bleaching technology is generally applied, but pulp density greatly reduces greater than the pumping efficiency of 17% middle underflow pump, and association with pulp bleaching concentration is difficult to surpass 17%; Free water took off to the greatest extent substantially during pulp density was starched greater than 25% o'clock, a contained humidity part wraps tightly in fiber surface, combine closely with the nascent parietal layer microfibre of fibrocyte, another part is present in the fibrocyte inner chamber, not can be used as the water of flowing carrier in the paper pulp, so high density stock pump carries pulp density to be difficult to exceed 25%, the domestic expert of having has manufactured high density stock pump, but transfer efficiency is not high and be difficult to and existing machinery mixer coupling is used, and makes the paper pulp high density bleaching be difficult to through engineering approaches and applies.
Summary of the invention
For overcoming the shortcoming and defect that prior art exists, the object of the present invention is to provide the high method for bleaching of a kind of paper pulp, compared with prior art, the present invention adopts helical feed slurry, association with pulp bleaching concentration height (17%～35%), can effectively reduce steam thermal energy consumption, reduces the bleaching drug dosage, reduce environmental pollution.
Purpose of the present invention is achieved through the following technical solutions:
(1) do not float the washing concentrating of paper pulp: do not float paper pulp and after washing, concentrate, obtain concentration and be the concentrated paper pulp afterwards 25% or more;
(2) extrusion dehydration of paper pulp: described concentrated back paper pulp adopts the parallel double-screw extruder to carry out extrusion dehydration by＞3.0 compression ratio, obtains concentration and be the high consistency stock more than 30%;
(3) dosing of paper pulp mixes: add the bleaching soup in high consistency stock, obtain expecting the medicine mixture;
(4) high dense one section bleaching of paper pulp: after will expecting that the medicine mixture is sent into the high density bleaching storehouse, be warming up to 90 ℃～120 ℃, boost to 0.1Mpa～0.3Mpa and bleach, bleaching time is 45 minutes～90 minutes, obtains bleaching slurry;
(5) the high dense second stage bleaching of paper pulp: bleached pulp is directly sent into high-density paste mill without washing, in the feeding process, in high-density paste mill, add bleaching powder simultaneously, obtain expecting the medicine mixture; Material medicine mixture is after the rubbing of high-density paste mill, the frictional heat of milling are warming up to 60 ℃～90 ℃, enter the high density bleaching storehouse again and be warming up to 90 ℃～100 ℃, bleach, bleaching time is 15 minutes～30 minutes, bleaching finishes the back blowing, through fiber disappear latent, the washing promptly obtain high beating degree bleached pulp, its whiteness is 80%ISO～85%ISO, beating degree＞20 ° SR.
The bleaching soup of described step (3) is the mixed solution of hydrogen peroxide and bleaching assistant, and described bleaching assistant comprises NaOH, chelating agent and stabilizing agent.
Described chelating agent is DTPA, relative oven dry stock quality, and the DTPA consumption is 0.1%～0.3%; Described stabilizing agent is a sodium metasilicate, relative oven dry stock quality, and the sodium metasilicate consumption is 0.5%～2.0%; The hydrogen peroxide consumption is 3.5%～4.0%, and sodium hydroxide concentration is 2.5%～3.5%.
The bleaching soup that described step (3) is mentioned is pressed from parallel double-screw extruder slurry with the pressure of 0.5MPa～1.5Mpa by measuring pump and is pushed to deviate to add, rapid expansion absorption soup behind the slurry abrupt release pressure.
The material medicine mixture that described step (4) is mentioned is sent into the high density bleaching storehouse by feeding screw.
Described step (5) bleaching powder is the sodium dithionite powder; Relative oven dry stock quality, sodium dithionite consumption 0.5%～1.5%.
The bleached pulp that described step (5) is mentioned is sent into high-density paste mill by feeding screw; Bleaching powder is carried by metering screw and is added.
The intensification of mentioning in the described step (4), boost employing saturated vapor or oxygen, saturated vapor is adopted in the intensification of mentioning in the step (5).
Paper pulp of the present invention is chemical pulp, mechanical pulp or chemi-mechanical pulp through chemistry, machinery or biological treatment.
Compared with prior art, the present invention has following advantage:
(1) the present invention adopt the power consumption of helical feed slurry low, carry slurry concentration height (17%～35%); Internal friction increase between the pulp fiber under the high dense state, high shear force makes the nascent parietal layer microfibre of fibrocyte divide silk, brooming in the course of conveying, can reduce papermaking making beating power consumption;
(2) the present invention adopts big compression ratio (＞3.0) that slurry is pushed, and slurry concentration is reached more than 30%, and the dissolved matter that the lignin that has dissolved in the slurry and other influence bleaching efficiency is extruded and removes, reduces the bleaching chemical consumption; High dense state extruding is down carried the frictional heat that effectively improves between the fiber, and mechanical energy is transformed into heat energy is raised to more than 60 ℃ slurry temperature, need not ad hoc slurry heating steam blender;
(3) promptly discharge after the big compression ratio of slurry of the present invention (＞3.0) extruding, slurry is extruded, rubs with the hands to grind the fiber finer cell wall is broken, air and part moisture are extruded and remove in the lumen, produce behind the slurry release of pressure that mode absorbs the bleaching medicament like " sponge sucks in water ", again through mechanical agitation mix the after bleaching medicament evenly, effect simultaneously inside and outside lumen apace, effectively improve bleaching efficiency; Promptly discharge after the slurry extruding, need not to accumulate the slurry pressurize, can reduce transmitting power consumption;
(4) slurry of mixed bleach medicament adopts the defeated pipe of spiral to be fed into the pyroreaction storehouse at once among the present invention, carries the flow process weak point can reduce power consumption, reduces thermal loss; High consistency stock (17%～35%) heat temperature raising is fast, only need replenish the temperature and pressure that small amount of steam or oxygen can reach the bleaching action requirement in the helical feed process, effectively reduces thermal energy consumption, increases economic efficiency.Hydrogen peroxide (H
2O
2) bleaching action single hop whiteness increment can reach more than the 20%ISO sodium dithionite (Na
2S
2O
4) bleaching action single hop whiteness increment can reach more than the 15%ISO; Adjust reaction temperature, pressure and reaction time can make high whiteness (＞80%ISO), high beating degree (＞20 ° of SR) bleached pulp.
Description of drawings
Fig. 1 is a process chart of the present invention.
The specific embodiment
The present invention is described in further detail below in conjunction with embodiment and accompanying drawing, but embodiments of the present invention are not limited thereto.
Embodiment 1
(1) is that 17% the masson pine chemical pulp that do not float concentrates after washing with concentration, obtains concentration and be 26.2% concentrated back paper pulp;
(2) adopt the parallel double-screw extruder described concentrated back paper pulp to be carried out extrusion dehydration, obtain concentration and be the high consistency stock more than 30% by＞3.0 compression ratio;
(3) push the place at parallel double-screw press master slurry hydrogen peroxide and bleaching assistant are pumped in the high consistency stock with the pressure of measuring pump with 0.5MPa, obtain expecting the medicine mixture; Bleaching assistant comprises NaOH, chelating agent, stabilizing agent; Relative oven dry stock quality, the hydrogen peroxide consumption is 3.5%, and sodium hydroxide concentration is 2.5%, and the DTPA consumption is 0.3%, and the sodium metasilicate consumption is 0.5%;
(4) will expect that the medicine mixture is delivered to the high density bleaching storehouse with feeding screw, and add saturated vapor and be warming up to 95 ℃ that be forced into 0.1 Mpa and bleach, bleaching time is 45 minutes, obtains bleaching slurry;
(5) bleached pulp is directly imported high-density paste mill with feeding screw without washing, simultaneously with adding the sodium dithionite powder in the metering screw high-density paste mill, obtain expecting the medicine mixture in the feeding process; After going out high-density paste mill, material medicine mixture imports the high density bleaching storehouse with feeding screw, in the high density bleaching storehouse, feed saturated vapor again and be warming up to 95 ℃, bleaching time is 20 minutes, and reaction finishes the back blowing, promptly obtains high beating degree (20.3 ° of SR) bleached pulp through washing; Relative oven dry stock quality, the sodium dithionite consumption is 1.5%.
The whiteness of high dense one section bleaching disposed slurry is 71.5%ISO, and the whiteness of high dense second stage bleaching disposed slurry is 80.3%ISO.
Embodiment 2
(1) is that 20% the Eucalyptus chemical pulp that do not float concentrates after washing with concentration, obtains concentration and be 28% concentrated back paper pulp;
(2) adopt the parallel double-screw extruder described concentrated back paper pulp to be carried out extrusion dehydration, obtain concentration and be the high consistency stock more than 30% by＞3.0 compression ratio;
(3) push the place at parallel double-screw press master slurry hydrogen peroxide and bleaching assistant are pumped in the high consistency stock with the pressure of measuring pump with 1.0MPa, obtain expecting the medicine mixture; Bleaching assistant comprises NaOH, chelating agent, stabilizing agent; Relative oven dry stock quality, the hydrogen peroxide consumption is 4.0%, and sodium hydroxide concentration is 3.0%, and the DTPA consumption is 0.1%, and the sodium metasilicate consumption is 0.5%;
(4) high dense one section bleaching of paper pulp: will expect that the medicine mixture is conveyed into the high density bleaching storehouse with feeding screw, and add saturated vapor and be warming up to 110 ℃ that be forced into 0.2Mpa and bleach, bleaching time is 50 minutes, must bleach slurry;
(5) bleached pulp is directly imported high-density paste mill with feeding screw without washing, simultaneously with adding the sodium dithionite powder in the metering screw high-density paste mill, obtain expecting the medicine mixture in the feeding process; After going out high-density paste mill, material medicine mixture imports the high density bleaching storehouse with feeding screw; Feed saturated vapor again and be warming up to 100 ℃ in the high density bleaching storehouse, bleaching time is 25 minutes, and reaction finishes the back blowing, and, washing latent through disappearing promptly obtains high beating degree (23.5 ° of SR) bleached pulp; Relative oven dry stock quality, the sodium dithionite consumption is 0.5%.
The whiteness of high dense one section bleaching disposed slurry is 73.2%ISO, and the whiteness of high dense second stage bleaching disposed slurry is 82.4%ISO.
Embodiment 3
(1) is that 20% do not float Eucalyptus chemical pulp and bamboo pulp (mass ratio that does not float Eucalyptus chemical pulp and bamboo pulp is 2:1) concentrate after washing with concentration, obtains concentration and be 28% concentrated back paper pulp;
(2) adopt the parallel double-screw extruder described concentrated back paper pulp to be carried out extrusion dehydration, obtain concentration and be the high consistency stock more than 30% by＞3.0 compression ratio;
(3) push the place at parallel double-screw press master slurry hydrogen peroxide and bleaching assistant are pumped in the high consistency stock with the pressure of measuring pump with 1.5MPa, must expect the medicine mixture; Described bleaching soup is the solution of hydrogen peroxide; Bleaching assistant comprises NaOH, chelating agent, stabilizing agent; Relative oven dry stock quality, the hydrogen peroxide consumption is 4.0%, and sodium hydroxide concentration is 3.0%, and the DTPA consumption is 0.1%, and the sodium metasilicate consumption is 0.5%;
(4) high dense one section bleaching of paper pulp: will expect that the medicine mixture goes into the high density bleaching storehouse with helical feed, and add oxygen and be warming up to 110 ℃ that be forced into 0.2Mpa and bleach, bleaching time is 50 minutes, must bleach slurry;
(5) (4) are got bleached pulp and directly import high-density paste mill, simultaneously with adding the sodium dithionite powder in the metering screw high-density paste mill, must expect the medicine mixture in the feeding process with feeding screw without washing; After going out high-density paste mill, material medicine mixture imports the high density bleaching storehouse with feeding screw; Feed saturated vapor again and be warming up to 100 ℃ in the high density bleaching storehouse, bleaching time is 25 minutes, and reaction finishes the back blowing, and, washing latent through disappearing promptly obtains high beating degree (23.8 ° of SR) bleached pulp; Relative oven dry stock quality, the sodium dithionite consumption is 0.5%.
The whiteness of high dense one section bleaching disposed slurry is 72.2%ISO, and the whiteness of high dense second stage bleaching disposed slurry is 81.4%ISO.
The foregoing description only is preferred implementation of the present invention; but embodiments of the present invention are not restricted to the described embodiments; other are any not to deviate from change, the modification done under spiritual essence of the present invention and the principle, substitute, combination, simplify; all should be the substitute mode of equivalence, be included within protection scope of the present invention.
Claims (8)
1. paper pulp high density bleaching method is characterized in that processing step is as follows:
(1) do not float the washing concentrating of paper pulp: do not float paper pulp and after washing, concentrate, obtain concentration and be the concentrated paper pulp afterwards 25% or more;
(2) extrusion dehydration of paper pulp: described concentrated back paper pulp adopts the parallel double-screw extruder to carry out extrusion dehydration by＞3.0 compression ratio, obtains concentration and be the high consistency stock more than 30%;
(3) dosing of paper pulp mixes: add the bleaching soup in high consistency stock, obtain expecting the medicine mixture;
(4) high dense one section bleaching of paper pulp: after will expecting that the medicine mixture is sent into the high density bleaching storehouse, be warming up to 90 ℃～120 ℃, boost to 0.1Mpa～0.3Mpa and bleach, bleaching time is 45 minutes～90 minutes, obtains bleaching slurry;
(5) the high dense second stage bleaching of paper pulp: bleached pulp is directly sent into high-density paste mill without washing, in the feeding process, in high-density paste mill, add bleaching powder simultaneously, obtain expecting the medicine mixture; Material medicine mixture is after the rubbing of high-density paste mill, the frictional heat of milling are warming up to 60 ℃～90 ℃, enter the high density bleaching storehouse again and be warming up to 90 ℃～100 ℃, bleach, bleaching time is 15 minutes～30 minutes, bleaching finishes the back blowing, promptly obtains high beating degree bleached pulp through disappear latent, washing of fiber.
2. paper pulp high density bleaching method according to claim 1 is characterized in that the bleaching soup of described step (3) is the mixed solution of hydrogen peroxide and bleaching assistant, and described bleaching assistant comprises NaOH, chelating agent and stabilizing agent.
3. paper pulp high density bleaching method according to claim 2 is characterized in that described chelating agent is DTPA, relative oven dry stock quality, and the DTPA consumption is 0.1%～0.3%; Described stabilizing agent is a sodium metasilicate, relative oven dry stock quality, and the sodium metasilicate consumption is 0.5%～2.0%, and the hydrogen peroxide consumption is 3.5%～4.0%, and sodium hydroxide concentration is 2.5%～3.5%.
4. according to claim 1 or 3 described paper pulp high density bleaching methods, it is characterized in that the bleaching soup that described step (3) is mentioned pushes to deviate to add from parallel double-screw extruder slurry by the pressure of measuring pump with 0.5MPa～1.5Mpa.
5. paper pulp high density bleaching method according to claim 4 is characterized in that, the material medicine mixture that described step (4) is mentioned is sent into the high density bleaching storehouse by feeding screw.
6. paper pulp high density bleaching method according to claim 5 is characterized in that, described step (5) bleaching powder is the sodium dithionite powder; Relative oven dry stock quality, the sodium dithionite consumption is 0.5%～1.5%.
7. paper pulp high density bleaching method according to claim 6 is characterized in that the bleached pulp that described step (5) is mentioned is sent into high-density paste mill by feeding screw; Bleaching powder is carried by metering screw.
8. paper pulp high density bleaching method according to claim 7 is characterized in that, the intensification of mentioning in the described step (4), boost employing saturated vapor or oxygen, and saturated vapor is adopted in the intensification of mentioning in the step (5).
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| CN2011101494255A CN102242514A (en) | 2011-06-07 | 2011-06-07 | Paper pulp high density bleaching method |
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| CN2011101494255A CN102242514A (en) | 2011-06-07 | 2011-06-07 | Paper pulp high density bleaching method |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102926254A (en) * | 2012-11-18 | 2013-02-13 | 天津容业达科技发展有限公司 | Pulping auxiliary added in normal-pressure low-temperature clean pulping process |
| CN103046425A (en) * | 2013-01-14 | 2013-04-17 | 岳阳林纸股份有限公司 | Pulping method of semi-chemical pulp prepared from masson pine |
| CN103790060A (en) * | 2012-10-31 | 2014-05-14 | 陈根长 | Pulping and bleaching technology of new aggregation state modified pulping process |
| CN106192502A (en) * | 2016-07-18 | 2016-12-07 | 山东太阳纸业股份有限公司 | A kind of method improving P RC APMP legal system slurry bleaching filtrate utilization rate |
| CN110725148A (en) * | 2019-10-18 | 2020-01-24 | 天津科技大学 | Technology for stabilizing pH value in hydrogen peroxide oxidation bleaching process |
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| CN101613976A (en) * | 2009-07-17 | 2009-12-30 | 中国林业科学研究院林产化学工业研究所 | Utilize the method for whole straw of mulberry tree branch preparing bleached chemi-mechanical pulp |
| CN101638859A (en) * | 2009-08-17 | 2010-02-03 | 中国林业科学研究院林产化学工业研究所 | High-whiteness bleaching method for high-yield bamboo wood pulp |
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2011
- 2011-06-07 CN CN2011101494255A patent/CN102242514A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101613976A (en) * | 2009-07-17 | 2009-12-30 | 中国林业科学研究院林产化学工业研究所 | Utilize the method for whole straw of mulberry tree branch preparing bleached chemi-mechanical pulp |
| CN101638859A (en) * | 2009-08-17 | 2010-02-03 | 中国林业科学研究院林产化学工业研究所 | High-whiteness bleaching method for high-yield bamboo wood pulp |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103790060A (en) * | 2012-10-31 | 2014-05-14 | 陈根长 | Pulping and bleaching technology of new aggregation state modified pulping process |
| CN102926254A (en) * | 2012-11-18 | 2013-02-13 | 天津容业达科技发展有限公司 | Pulping auxiliary added in normal-pressure low-temperature clean pulping process |
| CN102926254B (en) * | 2012-11-18 | 2018-02-27 | 天津容业达科技发展有限公司 | The pulping agents added during atmospheric low-temperature cleaning pulping |
| CN103046425A (en) * | 2013-01-14 | 2013-04-17 | 岳阳林纸股份有限公司 | Pulping method of semi-chemical pulp prepared from masson pine |
| CN106192502A (en) * | 2016-07-18 | 2016-12-07 | 山东太阳纸业股份有限公司 | A kind of method improving P RC APMP legal system slurry bleaching filtrate utilization rate |
| CN106192502B (en) * | 2016-07-18 | 2018-06-19 | 山东太阳纸业股份有限公司 | A kind of method for improving P-RC APMP legal systems slurry bleaching filtrate utilization rate |
| CN110725148A (en) * | 2019-10-18 | 2020-01-24 | 天津科技大学 | Technology for stabilizing pH value in hydrogen peroxide oxidation bleaching process |
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Application publication date: 20111116 |