CN105040500A - Elemental chlorine free bleaching method of reed pulp - Google Patents

Elemental chlorine free bleaching method of reed pulp Download PDF

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Publication number
CN105040500A
CN105040500A CN201510555854.0A CN201510555854A CN105040500A CN 105040500 A CN105040500 A CN 105040500A CN 201510555854 A CN201510555854 A CN 201510555854A CN 105040500 A CN105040500 A CN 105040500A
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China
Prior art keywords
pulp
chlorine
reed
hydrogen peroxide
naoh
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CN201510555854.0A
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Chinese (zh)
Inventor
刘艳兰
林本平
陈克复
马乐凡
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Changsha University of Science and Technology
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Changsha University of Science and Technology
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Priority to CN201510555854.0A priority Critical patent/CN105040500A/en
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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
    • D21C9/1057—Multistage, with compounds cited in more than one sub-group D21C9/10, D21C9/12, D21C9/16
    • 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
    • D21C9/1068—Bleaching ; Apparatus therefor with O2
    • 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
    • D21C9/12—Bleaching ; Apparatus therefor with halogens or halogen-containing compounds
    • D21C9/14—Bleaching ; Apparatus therefor with halogens or halogen-containing compounds with ClO2 or chlorites
    • 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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  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Paper (AREA)

Abstract

An elemental chlorine free bleaching method of reed pulp is characterized by sequentially comprising the steps of an oxygen delignification processing stage, a chlorine dioxide delignification stage, an alkaline hydrogen peroxide extraction stage and a chlorine dioxide whitening stage. In the alkaline hydrogen peroxide extraction stage, partial magnesium hydroxide is used for replacing sodium hydroxide to serve as an alkali source and replacing magnesium sulfate to serve as a protective agent of cellulose simultaneously. The elemental chlorine free bleaching method of the reed pulp is suitable for bleaching the reed pulp, simple in technology and easy to operate, the viscosity and the tensile index of the bleaching pulp are improved, AOX and COD of waste water are reduced, the environmental pollution of a paper mill is reduced, and prominent social benefits and ecological benefits are achieved.

Description

A kind of element chlorine free bleaching method of reed pulp
Technical field
The present invention relates to a kind of dioxde pulp bleaching process, particularly a kind of element chlorine free bleaching method of reed pulp.
Background technology
The timber resources of China extremely lacks, and paper making raw material bottleneck is particularly thorny.Reed pulp is a kind of reasonable non-wood fibrous raw material, unless fibrocyte content is comparatively outside hardwood pulp height, other biological data all close to or exceed hardwood pulp, as long as the paper product of available hardwood pulp all can use reed pulp.Along with the raising of paper and cardboard total output, the absolute demand amount of reed pulp is still very large, and reed pulp, as the good careless plasmoid of one, in China paper industry development, will play an important role.Therefore, the scientific and reasonable problem utilizing the non-wood materials such as reed can solve China's paper making raw material deficiency.
Adopt chlorine, the waste water that the conventional method of hypochlorite bleaching paper pulp produces produces a large amount of organochlorines for thing (AOX), its Main Ingredients and Appearance is chloro phenols, some toxicity is very big, wherein even also containing toxic very strong dioxin, these Toxics to the mankind and ecological environment very harmful, therefore a lot of country has carried out strict restriction to the content in bleaching effluent.China in 2008 promulgate " paper industry water pollutions discharge standard " in also using AOX generation as one of Con trolling index.In recent years, chlorine dioxide (D) is utilized to replace the method for bleaching of the element-free chlorine of chlorine to be developed.ClO 2be a kind of excellent bleaching agent, there is good delignification selectivity and good environmental effect, although and in ClO 2 bleaching process, still have AOX to produce, not yet find that wherein toxic material exists so far.
In the alkaline hydrogen peroxide bleaching of paper pulp, usually to add NaOH as alkali source, add magnesium sulfate as cellulosic protective agent.NaOH is highly basic, can cause lignin and a large amount of stripping of hemicellulose, paper pulp yield is declined, and increase the COD load of waste water, thus add the treatment cost of waste water.In addition, the high alkalinity in paper-making process can cause follow-up workshop section to form a large amount of anionic trashes, and interference institute uses the effectiveness of chemicals, thus increases the consumption of chemicals, increase production cost, reduction product quality.
Research both domestic and external in recent years shows, in the alkaline hydrogen peroxide bleaching of many wood chemistry mechanical pulps, magnesium hydroxide can partially or completely replace NaOH as alkali source ,and the problem that can overcome caused by NaOH.HeZ. wait the hydrogen peroxide bleaching research of people (TappiJournal, 2004,3 (12): 27) to cork thermomechanical pulp to find, magnesium hydroxide can improve the light scattering coefficient of pulping, reduces the COD of bleaching effluent simultaneously.
ThakoreA.; OeiJ. people (Pulp & PaperCanada is waited; 2005; 106 (5): 46-49) the element chlorine free bleaching flow process of DE (Eop) D is adopted to bleach softwood kraft pulp; find in alkaline pressured hydrogen peroxide bleaching section (Eop section); magnesium hydroxide can replace magnesium sulfate as cellulose protective agent in order to protect paper strength, can also reduce the consumption of this drift section NaOH simultaneously, reduces production cost.But domestic and international chemi-mechanical pulp and chemical pulp magnesium hydroxide mainly being concentrated on to timber as the alkali source of alkaline hydrogen peroxide bleaching and the protectant research of cellulose at present, to non-wood material, the research as Reed Kraft Pulp yet there are no relevant report.
With NaOH and MgSO 4difference, Mg (OH) 2with function anion (OH -) and CATION (Mg 2+), thus there is alkalescence and can cellulose be protected.Take over dry as benchmark, 0.73kgMg (OH) 2chemically be equivalent to 1.00kgNaOH, and 0.48kgMg (OH) 2with 1.00kgMgSO 4magnesium ion containing equivalent.
The patent No. is CN101463573B, the patent of invention that denomination of invention is " a kind of straw pulp bleaching technique " discloses a kind of by oxygen delignification, chlorine dioxide delignification, alkali density process, the element chlorine free bleaching method of the chlorine dioxide section of brightening composition, alkali density processing section disclosed in this patent is as unique alkali source with NaOH.
Summary of the invention
The object of this invention is to provide a kind of employing oxygen delignification; hydrogen peroxide; the low stain bleaching process being suitable for reed pulp of low Chlorine; replace NaOH as the alkali source of alkaline hydrogen peroxide extracting section using magnesium hydroxide part, replace magnesium sulfate as the cellulose protective agent of this section simultaneously.This technique, for the quality improving reed bleached pulp, reduces the pollution important in inhibiting of reed pulp bleaching to ecological environment.
The present invention is achieved by the following technical solutions: following involved slurry concentration if no special instructions, is mass percent; Involved reagent, the consumption of medicine, if no special instructions, be all for oven dry stock.
An element chlorine free bleaching method for reed pulp, sequentially comprises the steps:
(1) oxygen delignification section (O):
In order to reduce the consumption of chlorine dioxide in follow-up drift section, do not float Reed Kraft Pulp and carry out oxygen delignification preliminary treatment, delignification rate controls at 40-50%, and namely the Kappa number of Reed Kraft Pulp is down to 7-8 from 12-15, can ensure that paper pulp is while delignification like this, strength character keeps good.Its process conditions are: reaction temperature 95-110 DEG C, tower top oxygen pressure 0.4-0.5MPa, time 60-90min, relative to oven dry stock quality, and pulp quality concentration 10-14%, sodium hydroxide concentration 3-4%, magnesium sulfate consumption 0.5-1.0%.
(2) chlorine dioxide delignification stages (D0):
Its objective is the residual lignin content in order to remove further after oxygen delignification in paper pulp.Process conditions are: Chlorine 0.6-1.0%, endpoint pH 3.0 ~ 4.5, reaction temperature 50-75 DEG C, reaction time 60-120min, pulp density 10-14%.
(3) alkaline hydrogen peroxide extracting section (Ep):
Its objective is and reduce product to neutralize still residual acid lignin in the slurry, increase the solubility of acidic materials, to be washed out better in slurry washing process, to through D 0section processes and slurry after washing carries out alkali density, adds hydrogen peroxide, can further improve the whiteness of bleached pulp.Its process conditions are: hydrogen peroxide use 0.5-1.5%; NaOH consumption 2.0-3.0%; the ratio that magnesium hydroxide replaces NaOH is 0-75%; magnesium hydroxide replaces magnesium sulfate as cellulosic protective agent simultaneously; do not add magnesium sulfate in addition; pulp density is 10-14%, reaction temperature 60-80 DEG C, reaction time 60-120min.
(4) the chlorine dioxide section of brightening (D1): its objective is the whiteness in order to improve paper pulp further.Process conditions are: Chlorine 0.1-0.6%, endpoint pH 6.0 ~ 6.5, reaction temperature 50-75 DEG C, reaction time 60-120min, pulp density 10-14%.
The present invention compared with prior art has following outstanding advantage:
1, when ensureing pulp strength, carry out oxygen delignification, oxygen delignification rate, at 40-50%, can reduce the consumption of chlorine dioxide in following bleaching, thus further reduces the content of AOX in waste water.
2, obviously reduce the COD in bleaching effluent, through inspection, the waste water COD of embodiment 1-3 all only uses NaOH to reduce more than 15% as the waste water COD of single alkali source than alkaline hydrogen peroxide extracting section (Ep).
3, due to the alkalescent of magnesium hydroxide ,magnesium hydroxide part is starched after replacing the drift of NaOH, and its viscosity and tensile index are starched higher than after the drift of NaOH as single alkali source.
4, chemically the one-tenth of product was seen originally, reduced the consumption of chemicals, thus reduced cost, improved the economic benefit of enterprise.
5, the final one-tenth pulp brightness of reed bleached pulp reaches 85-87%ISO, and strength character is good, meets the pulping requirements of high-grade paper.
6, this law technique is simple to operation, has using value, alleviates the problem of environmental pollution in paper mill, has significant social benefit and ecological benefits.
Detailed description of the invention
Below in conjunction with embodiment, the present invention is further illustrated, but the scope of protection of present invention not scope of representing in embodiment of limitation.Unless stated otherwise, below, in embodiment, related substance consumption refers to the consumption of the quality relative to oven dry stock.In embodiment, according to OH -gram molecule content with Mg (OH) 2part replaces NaOH to bleach.Such as, in embodiment 1, when substitute proportion is 25%, namely there is the OH of 25% -derive from Mg (OH) 2, total alkali charge is 3.0%NaOH, and corresponding alkali addition is 2.25%NaOH and 0.55%Mg (OH) 2.With OH -content be benchmark, NaOH contains the OH of 42.51% -ion, and Mg (OH) 2containing 58.32%.Magnesium hydroxide in remaining embodiment and the addition of NaOH calculate according to above method.
Embodiment 1: a kind of element chlorine free bleaching method of reed pulp
The brown stock that the present embodiment uses is the reed pulp adopting sulfate process continuously cooking to obtain, Kappa number 15, whiteness 38%ISO.
Step 1: oxygen delignification section (O):
Do not float Reed Kraft Pulp, adjustment slurry is dense adds the NaOH of 4% under 10% condition, the magnesium sulfate of 1.0%, reacts 70min, then clean at 100 DEG C.
Step 2: chlorine dioxide delignification stages (D0):
Paper pulp after oxygen delignification, regulate slurry dense to 10%, react 120min, Chlorine 1.0% under 70 DEG C of conditions, control endpoint pH 4.0 ~ 4.5, reaction terminates afterwash paper pulp.
Step 3: alkaline hydrogen peroxide extracting section (Ep):
Paper pulp after chlorine dioxide delignification, regulates slurry dense to 10%, hydrogen peroxide use 1.5%, NaOH consumption 3.0%, the ratio that magnesium hydroxide replaces NaOH is 25%, and addition amount of sodium hydroxide is 2.25%, magnesium hydroxide addition is 0.55%, reaction temperature 65 DEG C, reaction time 120min.
Step 4: the chlorine dioxide section of brightening (D1):
Paper pulp after alkali density, regulate slurry dense to 10%, Chlorine 0.4%, endpoint pH 6.0 ~ 6.5, reaction temperature 70 DEG C, reaction time 110min, reaction terminates afterwash paper pulp, copy paper.
After testing, the whiteness of the present embodiment gained finished pulp is 87.3%ISO, and beating degree is 24 ° of SR, and tensile index is 50.6Nm.g -1, burst index is 4.6KPa*m 2.g -1, viscosity is 792mL.g -1, COD growing amount is 920mg.L -1.
Embodiment 2: a kind of element chlorine free bleaching method of reed pulp
The brown stock that the present embodiment uses is the reed pulp adopting sulfate process continuously cooking to obtain, Kappa number 13, whiteness 40%ISO.
Step 1: oxygen delignification section (O):
Do not float Reed Kraft Pulp, adjustment slurry is dense adds the NaOH of 4% under 10% condition, the magnesium sulfate of 0.5%, reacts 60min, then clean at 105 DEG C.
Step 2: chlorine dioxide delignification stages (D0):
Paper pulp after oxygen delignification, regulate slurry dense to 10%, react 120min, Chlorine 0.8% under 70 DEG C of conditions, control endpoint pH 4.0 ~ 4.5, reaction terminates afterwash paper pulp.
Step 3: alkaline hydrogen peroxide extracting section (Ep):
Paper pulp after chlorine dioxide delignification, regulate slurry dense to 10%, hydrogen peroxide use 1.0%, NaOH consumption 2.5%, the ratio that magnesium hydroxide replaces NaOH is 75%, and addition amount of sodium hydroxide is 0.63%, magnesium hydroxide addition is 1.37%, reaction temperature 75 DEG C, reaction time 120min, reaction terminates afterwash paper pulp.
Step 4: the chlorine dioxide section of brightening (D1):
Paper pulp after alkali density, regulate slurry dense to 10%, Chlorine 0.5%, endpoint pH 6.0 ~ 6.5, reaction temperature 70 DEG C, reaction time 120min, reaction terminates afterwash paper pulp, copy paper.
After testing, the whiteness of the present embodiment gained finished pulp is 85.6%ISO, and beating degree is 27 ° of SR, and tensile index is 53.5Nm.g -1, burst index is 4.9KPa*m 2.g -1, viscosity is 820mL.g -1, COD growing amount is 873mg.L -1.
Embodiment 3: a kind of element chlorine free bleaching method of reed pulp
The brown stock that the present embodiment uses is the reed pulp adopting sulfate process continuously cooking to obtain, Kappa number 12, whiteness 41%ISO.
Step 1: oxygen delignification section (O):
Do not float Reed Kraft Pulp, adjustment slurry is dense adds the NaOH of 3.5% under 10% condition, the magnesium sulfate of 0.6%, reacts 60min, then clean at 100 DEG C.
Step 2: chlorine dioxide delignification stages (D0):
Paper pulp after oxygen delignification, regulate slurry dense to 10%, react 120min, Chlorine 0.8% under 60 DEG C of conditions, control endpoint pH 4.0 ~ 4.5, reaction terminates afterwash paper pulp.
Step 3: alkaline hydrogen peroxide extracting section (Ep):
Paper pulp after chlorine dioxide delignification, regulates slurry dense to 12%, hydrogen peroxide use 0.8%, NaOH consumption 2.0%, the ratio that magnesium hydroxide replaces NaOH is 50%, and addition amount of sodium hydroxide is 1.0%, magnesium hydroxide addition is 0.73%, reaction temperature 70 DEG C, reaction time 100min.
Step 4: the chlorine dioxide section of brightening (D1):
Paper pulp after alkali density, regulate slurry dense to 10%, Chlorine 0.4%, endpoint pH 6.0 ~ 6.5, reaction temperature 60 DEG C, reaction time 120min, reaction terminates afterwash paper pulp, copy paper.
After testing, the whiteness of the present embodiment gained finished pulp is 87.1%ISO, and beating degree is 25 ° of SR, and tensile index is 52.8Nm.g -1, burst index is 4.6KPa*m 2.g -1, viscosity is 810mL.g -1, COD growing amount is 902mg.L -1.

Claims (2)

1. an element chlorine free bleaching method for reed pulp, is characterized in that: sequentially comprise the steps:
(1) oxygen delignification section (O): reaction temperature 95-110 DEG C, tower top oxygen pressure 0.4-0.5MPa, time 60-90min, relative to oven dry stock quality, pulp quality concentration 10-14%, sodium hydroxide concentration 3-4%, magnesium sulfate consumption 0.5-1.0%;
(2) chlorine dioxide delignification stages (D0): Chlorine 0.6-1.0%, endpoint pH 3.0 ~ 4.5, reaction temperature 50-75 DEG C, reaction time 60-120min, pulp density 10%-14%;
(3) alkaline hydrogen peroxide extracting section (Ep): hydrogen peroxide use 0.5-1.5%, NaOH consumption 2.0-3.0%, the ratio that magnesium hydroxide replaces NaOH is 0-75%, magnesium hydroxide replaces magnesium sulfate as cellulosic protective agent simultaneously, do not add magnesium sulfate, pulp density is 10-14%, reaction temperature 60-80 DEG C, reaction time 60-120min;
(4) the chlorine dioxide section of brightening (D1): Chlorine 0.1-0.6%, endpoint pH 6.0 ~ 6.5, reaction temperature 50-75 DEG C, reaction time 60-120min, pulp density 10-14%.
2. the fully chlorine-free bleaching method of a kind of reed pulp according to claim 1, it is characterized in that reed brown stock is kraft cooking slurry, the performance indications of slurry are Kappa number 12-15, whiteness 38-41%ISO.
CN201510555854.0A 2015-09-06 2015-09-06 Elemental chlorine free bleaching method of reed pulp Pending CN105040500A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114606788A (en) * 2022-03-07 2022-06-10 华南理工大学 Method for synchronously preparing dissolving pulp and furfural from wood fibers

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Publication number Priority date Publication date Assignee Title
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WO2008076268A2 (en) * 2006-12-18 2008-06-26 International Paper Company A process in a (d) stage bleaching of hardwood pulps in a presence of mg(oh)2
CN101463573A (en) * 2008-12-08 2009-06-24 沅江纸业有限责任公司 Straw pulp bleaching technique
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Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1940177A (en) * 2006-09-01 2007-04-04 华泰集团有限公司 Three-sectional bleaching process of vegetable-fible slurry
WO2008076268A2 (en) * 2006-12-18 2008-06-26 International Paper Company A process in a (d) stage bleaching of hardwood pulps in a presence of mg(oh)2
CN101463573A (en) * 2008-12-08 2009-06-24 沅江纸业有限责任公司 Straw pulp bleaching technique
CN104611971A (en) * 2014-12-22 2015-05-13 南宁糖业股份有限公司 A system and a method for bleaching bagasse pulp with chlorine dioxide

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114606788A (en) * 2022-03-07 2022-06-10 华南理工大学 Method for synchronously preparing dissolving pulp and furfural from wood fibers

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Application publication date: 20151111