CN101760978A - Pulp-bleaching technique - Google Patents
Pulp-bleaching technique Download PDFInfo
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- CN101760978A CN101760978A CN200910272621A CN200910272621A CN101760978A CN 101760978 A CN101760978 A CN 101760978A CN 200910272621 A CN200910272621 A CN 200910272621A CN 200910272621 A CN200910272621 A CN 200910272621A CN 101760978 A CN101760978 A CN 101760978A
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- slurry
- bleaching
- pulp
- whiteness
- lignin
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Abstract
The invention relates to a pulp-bleaching technique. 40 percent to 50 percent by weight of residual lignin of boiled pulp is removed by way of oxygen delignification, hydrogen peroxide is then utilized to further remove the lignin, and finally, calcium hypochlorite is used for supplementary bleaching. The yield of bleached pulp is high, moreover, the whiteness of bleached pulp is high, the stability of whiteness is good, and the pollution load of bleaching waste liquor is low.
Description
Technical field
The invention belongs to pulping and paper-making industry chemical pulping paper pulp bleaching process, is the improvement to the CEH bleaching process, and this improved bleaching process both can be used for the hardwood pulp bleaching, also can be used for non-pulp bleaching.
Background technology
Traditional non-wood-fiber paper pulp and broad-leaved wood fiber paper pulp mainly take CEH tri-stage bleaching technology to produce, but CEH tri-stage bleaching technology has the bleaching whiteness and yield is low, the pulp viscosity loss is big, waste water load is heavy and the shortcoming of wastewater with A X severe overweight.For this reason, National Development and Reform Committee in " papermaking industry development policy " chapter 4 of in November, 2007 promulgation expressly provide " encourage growth use High Yield Pulping Technology, biotechnology, low pollute pulping technique, in dense technology, element-free chlorine or total chlorine free bleaching technology "; Article 23, regulation " forbids that project begun newly adopts elemental chlorine (being liquid chlorine) bleaching process (existing enterprise should progressively eliminate) ".
Summary of the invention
The object of the present invention is to provide a kind of improved paper pulp bleaching process, is the new technology that meets the element chlorine free bleaching of national industrial policies.Adopt oxygen delignification bleaching technology (O) and peroxide bleaching technology (P) and hypochlorite (H) bleaching technology to form the OPH bleaching process and substitute original CEH bleaching process, can improve bleaching whiteness and bleached stlck chest yield, improve pulp strength, reduce wastewater discharge and wastewater with A X.
Technical scheme of the present invention is: remove about 50% of paper pulp residual lignin after the boiling by oxygen delignification bleaching, utilize hydrogen peroxide (H again
2O
2) further remove lignin, with whiteness that improves paper pulp and the stability of floating the back pulp brightness, use calcium hypochlorite (Ca (ClO) 2) to bleach as a supplement at last, pulp brightness is reached more than 80%.
First section is adopted the technological requirement of oxygen delignification bleaching to be:
Slurry concentration 12-16%
Temperature 90-120 ℃
Flow of oxygen 15-20kg/t slurry
NaOH consumption 2-4kg/t slurry
Magnesium sulfate consumption 0.1-0.5%
Second section is adopted the technological requirement of hydrogen peroxide bleaching to be;
Slurry concentration 8-12%
Slurry temperature 40-60 ℃
H
2O
2Consumption 12-18kg/t slurry
Slurry pH value 10-11
Slurry hardness 2-4 (K value)
Time 40-90min
The 3rd section is adopted a small amount of calcium hypochlorite bleaching to improve into pulp brightness;
Bleachability 1.2-2.5%
Concentration 8-12%
Temperature 38-42 ℃
Time 60-120min
Become pulp brightness 80-85%
Oxygen delignification is actually the process of thick slurry delignification.Under alkali condition, the oxidation reaction of oxygen and lignin is very fast, makes lignin degradation produce aliphatic acid, and is dissolved in the alkaline solution.Therefore alleviated to a certain extent cellulosic oxidation.C on the fiber
2, C
3Oxidized and cause the fracture of grape glycosidic bond, further be oxidized to uronic acid, therefore need to add magnesium salts as protective agent, suppress cellulosic degraded.It is capable of being combined in the chemical recovery system that oxygen floats waste liquid, thereby significantly reduce content and the colourity of COD in the bleaching effluent, also reduced the expense of wastewater treatment.
The peroxide bleaching and the various chloride bleaching agent mechanism of action are different, chlorine bleaches is a structure of destroying lignin, pigment by oxidation, therefore become the low-molecular material stripping, can reduce yield of bleached pulp, and peroxide does not react to the primary structure of lignin.Alkaline hydrogen peroxide can be removed the most of chromophoric group on the lignin side chain, the class lignin structure is broken and generates colourless aliphatic compounds, but do not make lignin degradation arrive soluble degree, thereby yield of bleached pulp height, and bleached pulp whiteness height, retention of whiteness is good, and the bleaching waste liquor pollutional load is little.
The specific embodiment
Raw materials such as reed, wheat straw, poplar are through alkaline cooking, and plant material is broken down into paper pulp fiber, purify through screening again, extract the fiber of bleaching usefulness, enter bleachery.
Improved bleaching process need increase builds oxygen delignification equipment, does not float paper pulp and at first adopts oxygen delignification technology, and second section is adopted hydrogen peroxide (H
2O
2), utilize the E section equipment of former CEH to get final product, the 3rd section is adopted calcium hypochlorite (H) bleaching, utilizes the H section equipment of former CEH to get final product.
Case study on implementation 1:
With bleaching process bleaching reed pulp of the present invention, concrete process conditions are as follows:
1, first section: the oxygen delignification section: slurry concentration 13wt%, 95 ℃ of temperature, oxygen (100%) consumption 15.8kg/t slurry, NaOH consumption 3kg/t slurry, the magnesium sulfate consumption is the 0.3wt% of slurry, water flush away residue.
2, second section; The concentration of washing back reed pulp is 11wt%, at first adds NaOH and regulates pH value to 11, adds H subsequently
2O
2The 13kg/t slurry, 55 ℃ of slurry temperatures (need not heat) enter reaction tower through double roller mixer, handle 60min, wash with water then, the flush away reaction residue, pulp brightness reaches 70%.
3, the 3rd section; Adopt the calcium hypochlorite post-bleach,
Slurry concentration 10wt%
Bleachability 1.5%
40 ℃ of temperature
Time 80min
Wash the dereaction residue with water, become pulp brightness to reach 80%.
Compare with the CEH bleaching results
| Bleaching method | Total available chlorine % | Whiteness % | Baking back whiteness % | Whiteness reduces % | Bleached pulp viscosity ml/g | Bleached stlck chest yield % | Bleach total CODkg/t | Integrated cost unit/ton slurry |
| ??CEH | ??8 | ??78.0 | ??67.5 | ??13.4 | ??570 | ??92 | ??198.3 | ??2913 |
| ??OPH | ??1.5 | ??80.2 | ??75.8 | ??5.5 | ??866 | ??96 | ??65.8 | ??2789 |
From the data of two kinds of technology comparison production test of case study on implementation 1 as can be seen, bleaching process of the present invention is used for bleached reed pulp and has improved whiteness and retention of whiteness than former technology, has improved yield and pulping intensity, has reduced disposal of pollutants and integrated cost and has reduced.
Case study on implementation 2
With bleaching process bleaching poplar slurry of the present invention, concrete process conditions are as follows;
1, first section: the oxygen delignification section: slurry concentration 15%, 120 ℃ of temperature, oxygen (100%) consumption 18kg/t slurry, NaOH consumption 3.6kg/t slurry, magnesium sulfate consumption 0.45%, water flush away residue.
2, second section; The concentration of washing back poplar slurry is 11.2%, transfers pH value to 11, adds H
2O
2The 16kg/t slurry, 62 ℃ of slurry temperatures enter reaction tower through double roller mixer, handle 90min, wash with water then, the flush away reaction residue, pulp brightness reaches 74%.
3, the 3rd section; Adopt the calcium hypochlorite post-bleach,
Slurry concentration 10.5%
Bleachability 2.5%
42 ℃ of temperature
Time 100min
Wash the dereaction residue with water, become pulp brightness to reach 83.7%.
Compare with the CEH bleaching results
| Bleaching method | Total available chlorine % | Whiteness % | Baking back whiteness % | Whiteness reduces % | Bleached pulp viscosity ml/g | Bleached stlck chest yield % | Bleach total CODkg/t | Integrated cost unit/ton slurry |
| ??CEH | ??10 | ??80.1 | ??69.8 | ??12.9 | ??790 | ??92 | ??203.5 | ??3125 |
| ??OPH | ??2.5 | ??83.7 | ??79.3 | ??5.3 | ??1203 | ??96 | ??73.6 | ??3071 |
From the data of two kinds of technology comparison production test of case study on implementation 2 as can be seen, bleaching process of the present invention is used to bleach the poplar slurry and has improved whiteness and retention of whiteness than former technology, improved pulp yield and pulping intensity, reduced disposal of pollutants and integrated cost and reduced.
Claims (4)
1. the bleaching process of a paper pulp is removed the 40-50wt% of paper pulp residual lignin after the boiling by oxygen delignification bleaching, utilizes hydrogen peroxide further to remove lignin again, carries out post-bleach with calcium hypochlorite at last.
2. technology according to claim 1 is characterized in that the technological requirement of described oxygen delignification bleaching is: slurry concentration 12-16wt%, temperature 90-120 ℃, flow of oxygen 15-20kg/t slurry, NaOH consumption 2-4kg/t slurry, magnesium sulfate consumption 0.1-0.5wt%.
3. technology according to claim 1 and 2 is characterized in that the described technological requirement of utilizing hydrogen peroxide further to remove lignin is: slurry concentration 8-12wt%, slurry temperature 40-60 ℃, H
2O
2Consumption 12-18kg/t slurry, slurry pH value 10-11, slurry hardness K value=2-4, time 40-90min.
4. technology according to claim 1 and 2 is characterized in that described technological requirement of carrying out post-bleach with calcium hypochlorite is: bleachability 1.2-2.5%, and concentration 8-12wt%, temperature 38-42 ℃, time 60-120min becomes pulp brightness 80-85%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200910272621A CN101760978A (en) | 2009-11-03 | 2009-11-03 | Pulp-bleaching technique |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200910272621A CN101760978A (en) | 2009-11-03 | 2009-11-03 | Pulp-bleaching technique |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN101760978A true CN101760978A (en) | 2010-06-30 |
Family
ID=42492348
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN200910272621A Pending CN101760978A (en) | 2009-11-03 | 2009-11-03 | Pulp-bleaching technique |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102888775A (en) * | 2012-11-07 | 2013-01-23 | 王欣宜 | Bleaching process of paper pulp |
| CN103981753A (en) * | 2014-06-04 | 2014-08-13 | 云南云景林纸股份有限公司 | Method for pulping mixed broad-leaved woods |
| CN108589368A (en) * | 2018-02-07 | 2018-09-28 | 赵兴海 | A method of producing high-purity fiber using timber slurry |
| CN109930415A (en) * | 2017-12-15 | 2019-06-25 | 中国制浆造纸研究院有限公司 | A method of improving oxygen bleaching pulp strength |
| CN111315802A (en) * | 2017-11-07 | 2020-06-19 | 英格维蒂南卡罗来纳有限责任公司 | Process for preparing low-color lignin |
| CN112359631A (en) * | 2020-10-29 | 2021-02-12 | 陕西科技大学 | Method for bleaching chlorine-free bamboo pulp |
-
2009
- 2009-11-03 CN CN200910272621A patent/CN101760978A/en active Pending
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102888775A (en) * | 2012-11-07 | 2013-01-23 | 王欣宜 | Bleaching process of paper pulp |
| CN102888775B (en) * | 2012-11-07 | 2015-03-04 | 河南科技学院 | Bleaching process of paper pulp |
| CN103981753A (en) * | 2014-06-04 | 2014-08-13 | 云南云景林纸股份有限公司 | Method for pulping mixed broad-leaved woods |
| CN111315802A (en) * | 2017-11-07 | 2020-06-19 | 英格维蒂南卡罗来纳有限责任公司 | Process for preparing low-color lignin |
| CN109930415A (en) * | 2017-12-15 | 2019-06-25 | 中国制浆造纸研究院有限公司 | A method of improving oxygen bleaching pulp strength |
| CN108589368A (en) * | 2018-02-07 | 2018-09-28 | 赵兴海 | A method of producing high-purity fiber using timber slurry |
| CN108589368B (en) * | 2018-02-07 | 2020-07-31 | 江苏海德新材料有限公司 | Method for producing high-purity fiber by using wood pulp |
| CN112359631A (en) * | 2020-10-29 | 2021-02-12 | 陕西科技大学 | Method for bleaching chlorine-free bamboo pulp |
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Application publication date: 20100630 |