CN117090070A - Paper pulp bleaching process and system without acid treatment - Google Patents
Paper pulp bleaching process and system without acid treatment Download PDFInfo
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- CN117090070A CN117090070A CN202311052133.9A CN202311052133A CN117090070A CN 117090070 A CN117090070 A CN 117090070A CN 202311052133 A CN202311052133 A CN 202311052133A CN 117090070 A CN117090070 A CN 117090070A
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- pulp
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- reaction
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- 238000000034 method Methods 0.000 title claims abstract description 19
- 238000004076 pulp bleaching Methods 0.000 title claims abstract description 19
- 229920001131 Pulp (paper) Polymers 0.000 title claims abstract description 14
- 238000010306 acid treatment Methods 0.000 title abstract description 11
- 239000000706 filtrate Substances 0.000 claims abstract description 93
- 238000006243 chemical reaction Methods 0.000 claims abstract description 35
- 239000002738 chelating agent Substances 0.000 claims abstract description 21
- 238000005406 washing Methods 0.000 claims abstract description 18
- 239000002253 acid Substances 0.000 claims abstract description 15
- 229920005610 lignin Polymers 0.000 claims abstract description 10
- 229910021645 metal ion Inorganic materials 0.000 claims abstract description 10
- 238000010438 heat treatment Methods 0.000 claims abstract description 8
- 230000003647 oxidation Effects 0.000 claims abstract description 3
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 21
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims description 16
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 12
- 239000001301 oxygen Substances 0.000 claims description 12
- 229910052760 oxygen Inorganic materials 0.000 claims description 12
- OSVXSBDYLRYLIG-UHFFFAOYSA-N dioxidochlorine(.) Chemical compound O=Cl=O OSVXSBDYLRYLIG-UHFFFAOYSA-N 0.000 claims description 10
- 239000007788 liquid Substances 0.000 claims description 9
- 239000013522 chelant Substances 0.000 claims description 6
- 239000003381 stabilizer Substances 0.000 claims description 6
- 239000002699 waste material Substances 0.000 claims description 6
- 239000012066 reaction slurry Substances 0.000 claims description 5
- 239000004155 Chlorine dioxide Substances 0.000 claims description 4
- 239000000460 chlorine Substances 0.000 claims description 4
- 235000019398 chlorine dioxide Nutrition 0.000 claims description 4
- 239000000049 pigment Substances 0.000 claims description 2
- 238000004061 bleaching Methods 0.000 abstract description 12
- 239000003513 alkali Substances 0.000 abstract description 6
- 239000010865 sewage Substances 0.000 abstract description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 6
- 239000000126 substance Substances 0.000 abstract description 4
- 230000000694 effects Effects 0.000 abstract description 3
- 239000002184 metal Substances 0.000 abstract 1
- 230000001105 regulatory effect Effects 0.000 abstract 1
- 238000009897 hydrogen peroxide bleaching Methods 0.000 description 7
- 238000012216 screening Methods 0.000 description 3
- 230000029087 digestion Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000002378 acidificating effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000009920 chelation Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 150000007524 organic acids Chemical class 0.000 description 1
- 238000004537 pulping Methods 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
Classifications
-
- 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
- D21C3/00—Pulping cellulose-containing materials
- D21C3/02—Pulping cellulose-containing materials with inorganic bases or alkaline reacting compounds, e.g. sulfate processes
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
- D21C9/02—Washing ; Displacing cooking or pulp-treating liquors contained in the pulp by fluids, e.g. wash water or other pulp-treating agents
-
- 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
- D21C9/144—Bleaching ; Apparatus therefor with halogens or halogen-containing compounds with ClO2 or chlorites with ClO2/Cl2 and other bleaching agents in a multistage process
-
- 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
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/64—Paper recycling
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Wood Science & Technology (AREA)
- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Paper (AREA)
Abstract
The application discloses a paper pulp bleaching process and a system without acid treatment, wherein the process comprises the following steps: q section: pulp is taken and washed by a pulp washer; OP section: washing pulp in section Q, regulating pH to be alkaline, adding H 2 O 2 And O 2 Adding an alkaline chelating agent to carry out chelating treatment, uniformly mixing and then heating for reaction; DQ segment: after washing the OP pulp, clO is added 2 Selective oxidation of lignin; PO section: after washing DQ pulp, pH is adjusted to be alkaline, H is added 2 O 2 And O 2 And adding alkaline chelating agent to metal ionChelating treatment is carried out, and the bleached paper pulp is obtained after heating reaction after uniform mixing. The application cancels the acid treatment of the Q section, adds the chelating agent into the OP section for metal ion chelating treatment, reduces the consumption of acid while ensuring the bleaching effect, reduces the discharge of acid filtrate by changing the conveying mode of the washing water, reduces the consumption of alkali and other chemicals for adjusting the PH of a sewage treatment plant, and reduces the cost.
Description
Technical Field
The application belongs to the technical field of pulping bleaching, and particularly relates to an acid-free paper pulp bleaching process and system.
Background
The paper pulp bleaching process, namely the Q-OP-DQ-PO bleaching process, comprises an acid treatment and chelation treatment section Q, an oxygen-based hydrogen peroxide bleaching section OP, a chlorine dioxide bleaching section DQ and a hydrogen peroxide bleaching section PO which is based on hydrogen peroxide. In the pulp and paper making production, the first bleaching stage after screening oxygen and removing has one acid treating and chelating treating stage to treat metal ion in pulp with acid and chelating agent to prevent the metal ion from decomposing the hydrogen peroxide in the bleaching stage and affecting the hydrogen peroxide bleaching effect. The filtrate after washing in the acid treatment section is acidic (pH is 3-6), so that the waste liquid is not sent to the evaporation section and is directly discharged to a sewage treatment plant for treatment, a large amount of acid liquor is needed in the treatment mode, and the filtrate is needed to be neutralized by adding alkali to reach the discharge standard, so that the cost is increased.
Disclosure of Invention
The application aims to provide an acid-free paper pulp bleaching process and system, which solve the problems of high sewage discharge and high cost in the prior art.
The application adopts the technical scheme that the paper pulp bleaching process without acid treatment comprises the following steps:
(1) Q section: an acid-free treatment section, wherein pulp obtained after alkaline digestion, screening and oxygen removal is washed by a pulp washer;
(2) OP section: a hydrogen peroxide bleaching section for washing the pulp in the step (1), adding NaOH to adjust pH to be alkaline, and adding H 2 O 2 And O 2 Reacting lignin with a chromophoric group, adding an alkaline chelating agent to chelate metal ions, uniformly mixing, and heating for reaction;
(3) DQ segment: a chlorine dioxide bleaching section, which is used for adding ClO after washing the pulp in the step (2) 2 Selective oxidation of lignin and pigments;
(4) PO section: a hydrogen peroxide bleaching section for washing the paper pulp in the step (3), adding NaOH to adjust pH to be alkaline, and adding H 2 O 2 And O 2 Reacting lignin with chromophoric groups, adding an alkaline chelating agent to chelate metal ions, uniformly mixing, and heating for reaction to obtain bleached paper pulp.
Preferably, the pH of the Q-stage pulp is 10, the temperature is 75 ℃, and the concentration of the reaction pulp is 11-12%.
Preferably, the OP segment is also added with MgSO 4 As a stabilizer, the pH of the pulp reaction is 10-11, the reaction temperature is 95 ℃, the concentration of the reaction pulp is 11-12%, the unit consumption of the alkaline chelating agent is 1kg/adt, the unit consumption of hydrogen peroxide is 5kg/adt, and the unit consumption of oxygen is 10kg/adt.
Preferably, naOH is added to adjust the PH to 3.5-4, and Na is finally added to the DQ segment 2 S 2 O 3 Treatment of Cl in acid waste liquid after reaction － Ions.
Preferably, the chlorine dioxide unit consumption of the DQ segment is 13kg/adt, the reaction temperature is 65 ℃, and the concentration of the reaction slurry is 11-12%.
Preferably, the PO segment is added with MgSO 4 As a stabilizer, the pH of the pulp reaction is 9-10, the reaction temperature is 95 ℃, the concentration of the reaction pulp is 11-12%, the unit consumption of the alkaline chelating agent is 1kg/adt, the unit consumption of hydrogen peroxide is 10kg/adt, and the unit consumption of oxygen is 5kg/adt.
The utility model provides a paper pulp bleaching system of no sour processing, includes 3# pulp washer (1), 3# filtrate tank (2), 4# pulp washer (3), 4# filtrate tank (4), 5# pulp washer (5) and 5# filtrate tank (6), 3# pulp washer (1) are respectively through filtrate pipe and thick liquid pipe intercommunication 3# filtrate tank (2) and 4# pulp washer (3), 4# pulp washer (3) are respectively through filtrate pipe and thick liquid pipe intercommunication 4# filtrate tank (4) and 5# pulp washer (5), 5# pulp washer (5) are through filtrate pipe intercommunication 5# filtrate tank (6), be equipped with chelating agent addition point (11) on the thick liquid pipe that 4# pulp washer (3) and 5# pulp washer (5) are connected, adopt 1# filtrate pipe (7) intercommunication between 5# filtrate tank (6) and 3# filtrate tank (2).
Preferably, the No. 1 filtrate pipe (7) is provided with a No. 2 filtrate pipe (8) connected to the No. 4 filtrate tank (4).
Preferably, the 4# filtrate tank (4) is connected to the 1# filtrate pipe (7) through the 3# filtrate pipe (9), and the 3# filtrate pipe (9) is located at the rear end of the 2# filtrate pipe (8), and a cut-off valve (10) is arranged between the 2# filtrate pipe (8) and the 3# filtrate pipe (9) on the 1# filtrate pipe (7).
Compared with the prior art, the application changes the original Q section into the washing section after oxygen removal, cancels the acid treatment of the Q section, changes the chelating agent into the OP section for metal ion chelating treatment, reduces the consumption of acid while guaranteeing the bleaching effect, and simultaneously reduces the discharge of acid filtrate by changing the conveying mode of washing water, thereby reducing the consumption of alkali and other chemicals for adjusting PH of a sewage treatment plant, and the bleaching process has the advantages of energy conservation, consumption reduction, simple flow and convenient production adjustment.
Drawings
FIG. 1 is a schematic diagram of the structure of the present application.
Detailed Description
The application will be further explained in relation to the drawings of the specification, so as to be better understood by those skilled in the art.
Example 1
As shown in fig. 1, an acid-free pulp bleaching system comprises a 3# washer 1, a 3# filtrate tank 2, a 4# washer 3, a 4# filtrate tank 4, a 5# washer 5, and a 5# filtrate tank 6. The 3# pulp washer 1 is communicated with the 3# filtrate tank 2 and the 4# pulp washer 3 through filtrate pipes and pulp pipes, and a medium concentration vertical pipe and a Q section reaction tower are arranged between the 3# pulp washer 1 and the 4# pulp washer 3; the 4# pulp washer 3 is respectively communicated with the 4# filtrate tank 4 and the 5# pulp washer 5 through filtrate pipes and pulp pipes, a medium-concentration vertical pipe, an OP section reaction tower and an OP spraying pot are arranged between the 4# pulp washer 3 and the 5# pulp washer 5, a chelating agent adding point 11 is arranged on the pulp pipe connected with the 4# pulp washer 3 and the 5# pulp washer 5, and the acid treatment reaction section is canceled by changing the adding point of the chelating agent, so that the consumption of acid is reduced, the emission of acid filtrate is reduced, and the consumption of alkali and other chemicals for adjusting PH of a sewage treatment plant is reduced.
The 5# pulp washer 5 is communicated with the 5# filtrate tank 6 through a filtrate pipe, the 5# filtrate tank 6 is communicated with the 3# filtrate tank 2 through a 1# filtrate pipe 7, and the transmission of the filtrate in the 5# filtrate tank 6 to the 3# filtrate tank 2 is cut off by a cut-off valve 10.
The No. 1 filtrate pipe 7 is provided with a No. 2 filtrate pipe 8 which is connected to the No. 4 filtrate tank 4, so that the filtrate in the No. 5 filtrate tank 6 is conveyed to the No. 4 filtrate tank 4; the 4# filtrate tank 4 is connected to the 1# filtrate pipe 7 through the 3# filtrate pipe 9, and the 3# filtrate pipe 9 is located the 2# filtrate pipe 8 rear end, is equipped with the shut-off valve 10 between the 2# filtrate pipe 8 and the 3# filtrate pipe 9 on the 1# filtrate pipe 7, realizes that the filtrate in the 4# filtrate tank 4 is carried to the 3# filtrate tank 2.
Because of no acid treatment, the filtrate in the 3# filtrate tank 2, the 4# filtrate tank 4 and the 5# filtrate tank 6 are alkaline, the filtrate in the 5# filtrate tank 6 and the 4# filtrate tank 4 and the filtrate in the 3# filtrate tank 2 can be recycled, and the discharge amount of waste liquid is reduced.
Example 2
An acid-free pulp bleaching process comprising the steps of:
(1) Q section: the acid-free treatment section is that pulp obtained after alkaline digestion, screening and oxygen removal is washed by a pulp washer, wherein the pulp reaction PH is 10, the temperature is 75 ℃, the concentration of the reaction pulp is 11-12%, and the washing water consumption of the pulp washer is 3.8m 3 /adt。
(2) OP section: a hydrogen peroxide bleaching stage, wherein after the pulp in the step (1) is washed, naOH is added to adjust the PH to 10, and MgSO is added 4 As stabilizer, add H 2 O 2 And O 2 Reacting lignin with chromophoric group, adding alkaline chelating agent to chelate metal ion, mixing uniformly, heating to react at 95deg.C, concentrating the reaction slurry 11-12%, and concentrating H 2 O 2 Ionization under alkaline conditions to produce HO 2 － Ions, which oxidize lignin, to alpha － Carbonyl groups are particularly reactive; wherein, the unit consumption of the alkaline chelating agent is 1kg/adt, the unit consumption of hydrogen peroxide is 5kg/adt, and the unit consumption of oxygen is 10kg/adt.
(3) DQ segment: a chlorine dioxide bleaching section, which is used for adding ClO after washing the pulp in the step (2) 2 ，ClO 2 The bleaching paper pulp obtained after the reaction is not easy to turn yellow; clO (ClO) 2 HCl and organic acid are generated during bleaching, pH is reduced continuously, naOH is added to control pH to 3.5, and finallyNa is introduced into 2 S 2 O 3 Treatment of Cl in acid waste liquid after reaction － Ions, reduction of Cl － Ion impact on equipment and environment; the chlorine dioxide unit consumption of DQ segment is 13kg/adt, the reaction temperature is 65 ℃, and the concentration of reaction slurry is 11-12%.
(4) PO section: a hydrogen peroxide bleaching stage for washing the pulp of the step (3), adding NaOH to adjust pH to be alkaline, and adding MgSO 4 As stabilizer, add H 2 O 2 And O 2 Reacting lignin with a chromophoric group, adding an alkaline chelating agent to chelate metal ions, uniformly mixing, and heating for reaction to obtain bleached paper pulp; wherein the reaction PH is 9-10, the reaction temperature is 95 ℃, the reaction slurry concentration is 11-12%, the unit consumption of the alkaline chelating agent is 1kg/adt, the unit consumption of hydrogen peroxide is 10kg/adt, and the unit consumption of oxygen is 5kg/adt.
Wherein adt is ton air dried pulp, namely pulp containing 10% of water.
The application has no acid treatment in the whole process, reduces the discharge of acid waste liquid by half, and reduces the unit consumption of water, acid and alkali. Meanwhile, by changing the conveying mode of the washing water, the discharge of acid filtrate is reduced, so that the consumption of alkali and other chemicals for adjusting the PH of a sewage treatment plant is reduced, and the cost is comprehensively saved by 15-20%.
The above embodiments are only for illustrating the technical solution of the present application and not for limiting the same, and although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications and equivalents may be made thereto without departing from the spirit and scope of the present application, which is intended to be covered by the claims of the present application.
Claims (9)
1. An acid-free pulp bleaching process comprising the steps of:
(1) Q section: taking pulp which is steamed, screened and subjected to oxygen removal by an alkaline method, and washing by a pulp washer;
(2) OP section: washing the pulp in the step (1), adding NaOH to adjust pH to be alkaline, and adding H 2 O 2 And O 2 For lignin and chromophoresReacting the clusters, adding an alkaline chelating agent to chelate metal ions, uniformly mixing and heating for reaction;
(3) DQ segment: after washing the pulp of step (2), clO is added 2 Selective oxidation of lignin and pigments;
(4) PO section: washing the pulp in the step (3), adding NaOH to adjust pH to be alkaline, and adding H 2 O 2 And O 2 Reacting lignin with chromophoric groups, adding an alkaline chelating agent to chelate metal ions, uniformly mixing, and heating for reaction to obtain bleached paper pulp.
2. An acid-free pulp bleaching process according to claim 1, wherein said Q-stage pulp has a PH of 10 and a temperature of 75 ℃ and a reaction pulp consistency of 11-12%.
3. An acid-free pulp bleaching process according to claim 1, wherein said OP section further incorporates MgSO 4 As a stabilizer, the pH of the pulp reaction is 10-11, the reaction temperature is 95 ℃, the concentration of the reaction pulp is 11-12%, the unit consumption of the alkaline chelating agent is 1kg/adt, the unit consumption of hydrogen peroxide is 5kg/adt, and the unit consumption of oxygen is 10kg/adt.
4. An acid-free pulp bleaching process according to claim 1, wherein said DQ segment is adjusted to pH 3.5-4 by adding NaOH, and finally Na is added 2 S 2 O 3 Treatment of Cl in acid waste liquid after reaction － Ions.
5. The acid-free pulp bleaching process according to claim 1, wherein the chlorine dioxide consumption of DQ section is 13kg/adt, the reaction temperature is 65 ℃, and the concentration of the reaction pulp is 11-12%.
6. An acid-free pulp bleaching process according to claim 1, wherein said PO stage incorporates MgSO 4 As a stabilizer, the pH of the pulp reaction is 9-10, and the reaction temperature is highThe temperature is 95 ℃, the concentration of the reaction slurry is 11-12%, the unit consumption of the alkaline chelating agent is 1kg/adt, the unit consumption of hydrogen peroxide is 10kg/adt, and the unit consumption of oxygen is 5kg/adt.
7. An acid-free pulp bleaching system according to any one of claims 1-6, characterized by comprising a 3# pulp washer (1), a 3# filtrate tank (2), a 4# pulp washer (3), a 4# filtrate tank (4), a 5# pulp washer (5) and a 5# filtrate tank (6), wherein the 3# pulp washer (1) is respectively connected to the 3# filtrate tank (2) and the 4# pulp washer (3) through filtrate pipes and pulp pipes, the 4# pulp washer (3) is respectively connected to the 4# filtrate tank (4) and the 5# pulp washer (5) through filtrate pipes, the 5# pulp washer (5) is connected to the 5# pulp washer (6) through filtrate pipes, a chelating agent adding point (11) is arranged on the pulp pipe connecting the 4# pulp washer (3) and the 5# filtrate tank (2), and the 5# filtrate tank (6) is respectively connected to the 3# filtrate tank (2) through a 1# filtrate pipe (7).
8. An acid-free pulp bleaching system according to claim 7, characterized in that the 1# filtrate pipe (7) is provided with a 2# filtrate pipe (8) connected to a 4# filtrate tank (4).
9. An acid-free pulp bleaching system according to claim 1, characterized in that the 4# filtrate tank (4) is connected to the 1# filtrate pipe (7) via a 3# filtrate pipe (9), and that the 3# filtrate pipe (9) is located at the rear end of the 2# filtrate pipe (8), and that a shut-off valve (10) is arranged on the 1# filtrate pipe (7) between the 2# filtrate pipe (8) and the 3# filtrate pipe (9).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311052133.9A CN117090070A (en) | 2023-08-21 | 2023-08-21 | Paper pulp bleaching process and system without acid treatment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311052133.9A CN117090070A (en) | 2023-08-21 | 2023-08-21 | Paper pulp bleaching process and system without acid treatment |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117090070A true CN117090070A (en) | 2023-11-21 |
Family
ID=88779715
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311052133.9A Pending CN117090070A (en) | 2023-08-21 | 2023-08-21 | Paper pulp bleaching process and system without acid treatment |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117090070A (en) |
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2023
- 2023-08-21 CN CN202311052133.9A patent/CN117090070A/en active Pending
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