CN1103832C - Treatment of pulp with a chelating agent without using a bleaching tower - Google Patents
Treatment of pulp with a chelating agent without using a bleaching tower Download PDFInfo
- Publication number
- CN1103832C CN1103832C CN97181066A CN97181066A CN1103832C CN 1103832 C CN1103832 C CN 1103832C CN 97181066 A CN97181066 A CN 97181066A CN 97181066 A CN97181066 A CN 97181066A CN 1103832 C CN1103832 C CN 1103832C
- Authority
- CN
- China
- Prior art keywords
- chelating agent
- pulp
- feature
- paper pulp
- mix stages
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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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
- D21C9/02—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
- D21C9/1026—Other features in bleaching processes
- D21C9/1042—Use of chelating agents
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- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Wood Science & Technology (AREA)
- Paper (AREA)
- Detergent Compositions (AREA)
- Chemical And Physical Treatments For Wood And The Like (AREA)
- Hybrid Cells (AREA)
- Noodles (AREA)
Abstract
A method at chlorine-free bleaching of pulp where metals are removed by means of chelating agent. The chelating agent is mixed with the pulp in at least one effective mixing step without intermediate washing, whereafter the pulp without an intermediate tower passes directly to a pulp washer. The total retention time shall be at maximum 15 minutes, calculated after the chelating agent addition.
Description
The present invention relates to no chlorine chemistry medicine bleached chemical paper pulps.The present invention relates to a kind of method that adopts chelating agent to combine pretreating paper pulp with bleaching or rather.
The totally chlorine free bleaching (TCF) of chemical papermaking paper pulp is achieved success, and the global annual production of no chlorine paper pulp is about to reach 5,000,000 tons, considers that this method for bleaching introducing is less than 6 years, and its development is abnormal.In addition, also there are various variations in this method, and it is free from chloride that pre-bleaching is wherein arranged, and final bleaching is ECF (not having chlorine substantially) or TCF (totally chlorine free) type.
Most bleaching is to adopt no chlorine chemistry medicine, at first is to handle the paper making pulp that needs bleaching with the chelating agent of EDTA or DTPA type.The purpose that adds chelating agent is some metal ion, particularly manganese of removing in the paper pulp, copper, and iron etc. can have a negative impact to bleaching effect if these metal ions are stayed in the paper pulp.Chelating agent is normally represented with alphabetical Q.
Clean this paper pulp after the Q-step, as far as possible fully to remove the metal ion that exposes in the paper pulp.Bleach then, normally use hydrogen peroxide, sometimes also in conjunction with using oxygen.The hydrogen peroxide step represents that with alphabetical P the P step that oxygenation is strengthened is expressed as OP or PO, and wherein main chemicals is put in the first place.Empirical law is that the harmful metal ion number of removing from paper pulp is big more, and then bleaching in succession will be effective more.
A kind of with Q-step process paper pulp, the method with the bleaching of P-step is commonly referred to " Lignox " method then, is for example disclosed among the EP-A-402335.
Before QP-bleaching, it is lower until Kappa number to make initial paper pulp carry out the oxygen delignification usually.Kappa number before the bleaching is low to mean that available maximum bleaching effect increases in the later step, and bleaches needed chemicals and reduce.
In factory, the QP-bleaching is carried out the most by this way: at first by a pump, this pump makes pulp suspension pass through treatment step to paper pulp.Be blender, in blender, chelating agent added in the paper pulp thereafter.The step of next is a bleaching tower, and not having additional stirring in bleaching tower only is to pass through lentamente, carries out all remaining reactions in bleaching tower.Paper pulp is at last through a washing step, in this washing step flush away that expose with metal ion complexing.The liquid that is rich in metal ion that normally will discharge abandons.
The general condition that the Q-step adopts is: temperature is 70-90 ℃, and the time of staying is 1-2 hour, and pulp density is 10-14%, and the pH value is 5-7, and the inlet amount of chelating agent is 1-3 kilogram/ton paper pulp.According to these conditions, can reach good metal separation, if subsequently the low paper pulp of content of lignin is bleached (Kappa number is less than about 5), and if at a large amount of hydrogen peroxide (greater than 15 kilograms/ton) of this step use, then this separation is necessary.But if described paper pulp still contains a large amount of lignin (Kappa number is approximately higher than 5), and the hydrogen peroxide inlet amount is limited to about 5-10 kilogram/ton in step subsequently, then is not very strict for the requirement of removing metal fully.In this stage as long as remove less metal (being that reduction is less than 60%) with regard to enough another kind of situations be: it is very low situation that the tenor before the Q-step is compared with desired tenor after the Q-step.In such cases, can adopt the Q-process of simplifying a little.
It seems that from the viewpoint of the bleaching of strictness the Q-step itself is a non-essential processing procedure, because real bleaching does not take place in this step.For successful subsequently P-or PO-bleaching, it is necessary that Q-handles but as mentioned above.If can save cost greatly, because a complete blanching step is expensive not reducing simplification Q-step under the prerequisite of removing metal effect.
The present invention relates to the simplification of Q-step, particularly for Kappa number approximately greater than the processing of 5 paper pulp, and require the metal reduction to handle less than the chelating agent of 60% paper pulp.Simplify the minimizing that means the cost of investment relevant with traditional Q-step.
The present invention is based on surprising observations, and it is more much smaller than increasing the time of staying to the influence of Q-step effect to increase reaction temperature.This shows that according to traditional chemical kinetics, the Q-step is a DIFFUSION CONTROLLED, rather than reaction control.The Q-step should be carried out to such an extent that diffusion is quickened in other words, if can realize effectively, then total time of staying can reduce widely.
The method that the purpose of this invention is to provide a kind of chlorine-free bleaching, metal is wherein removed with chelating agent, described chelating agent is that at least one of 5-11 do not used in effective mix stages of bleaching tower and mixed with paper pulp at pH, and washing pulp in after final mix stages 15 minutes.At the Kappa number of the paper pulp of chelating agent before the stage more than 5, perhaps described chelating agent in the stage desired metal reduction less than 60%.The total addition level of chelating agent is 0.5-3 kilogram/ton paper pulp, is preferably 1-2 kilogram/ton paper pulp.The temperature of chelating agent in the stage is up to 110 ℃ more than 75 ℃.The pulp density of chelating agent in the stage is 2-16%.At least used two mix stages in the described method, chelating agent all adds in first mix stages, and mix stages subsequently only mixes again.Chelating agent also can add in several mix stages.Described chelating agent is EDTA type or DTPA type, also can be NTA type or DTPMP type.Described chelating agent carried out with mixing by high-intensity blender of paper pulp, the network of fibers in this blender comminution pulp, and cause tight contact between fiber and the chelating agent.
The best way that reduces diffusional resistance is the diffusion length that reduces reactant and the product that is discharged.Reach by mixing effectively on the commercial scale, for example in blender, do to stop for a long time.Like this, by effective mixing, just can shorten the time of staying in the Q-step.The number of times of blend step is not strict, but total incorporation time must perhaps should be used two mixing arrangements at least on certain critical level.Yet the number of times of blend step must be grasped in rational level because economically., must further bleach with the hydrogen peroxide of about 5-10 kilogram at most except that the oxygen that may exist approximately greater than 5 paper pulp for Kappa number, the number of times of suitable blend step is 1-2.If the metal reduction that will reach in the chelating agent step is limited, and do not need greater than 60%, then same conclusion also is suitable for.
When using two blend steps, certain time of staying is then preferably arranged between the blend step, but this time needn't grow because the diffusivity when still unmixed will be slowly than what can reach by mixing (for example in blender) many.Therefore, the time of staying between the blend step should be shorter than 10 minutes, is more preferably and is shorter than 5 minutes.Blend step should carry out one by one, washing in the middle of not having.Removing the needed washing step of metal from pulp suspension should carry out within 15 minutes after final blend step.
When using more than one blend step, all chelating agent should add in first blend step, and blend step subsequently only causes mixing again.Separately reinforced, making one of maximum three parts chelating agent material is in the end to add in the step, also is not what be harmful to, if mixing subsequently is enough effectively to talk about.
Chelating agent is EDTA (ethylenediamine tetra-acetic acid) type preferably, or DTPA (diethylene-triamine pentaacetic acid) type, but also can use the chelating agent of other type, for example NTA (nitrilotriacetic acid(NTA)) or DTPMP (diethylenetriamine pentamethylenophosphonic acid diethylene triamine pentamythylene phosphoricacid).The total amount of the chelating agent that is added should be 0.5-3 kilogram/ton paper pulp (calculating with pure chelating agent), is preferably 1-2 kilogram/ton paper pulp.
The temperature of Q-step should be more than 75 ℃, and is more suitable for more than 80 ℃, is more preferably more than 85 ℃.Desired pH scope is 5-11.Pulp density should be 2-16%.
By using high-intensity blender or another kind of can effectively the mixing and blender that the time of staying is enough, can obtain a kind ofly especially effectively mixing, and therefore obtain the homogeneous mixture of fiber and chelating agent.
Following table has been listed some results that single stage Q-handles, and it is to use high intensity mixer to carry out for 3 seconds, stop 40 minutes (not mixing) subsequently before pulp washing, and treatment temperature wherein is 95 ℃.For ease of relatively, also listed the data that traditional Q-handles here, this step is mixed chelating agent in traditional laboratory mode with paper pulp, and the time of staying subsequently is 60 minutes, and this step is carried out at 90 ℃.
Experiment:
Initial paper pulp is oxygen bleaching, and is coniferous sulfate type, and Kappa number is 10.1, and viscosity is 975dm
3/ t, brightness is 43%ISO.According to 10kg H
2O
2The Q of/t (OP) bleaches.
| PH=8.6 in the Q-step | Q step of the present invention | Q step in the routine techniques |
| Kappa number | 5.7 | 5.7 |
| Viscosity dm 3/kg | 771 | 807 |
| Brightness %ISO | 63.4 | 64.9 |
| PH=10.6 in the Q-step | Q step of the present invention | No Q step before the OP step |
| Kappa number | 5.7 | 6.1 |
| Viscosity dm 3/kg | 771 | 790 |
| Brightness %ISO | 62.2 | 59.1 |
Certainly, the present invention is not limited to the above embodiments, and can do various changes in the scope of patent claims.
Claims (10)
1. the method for a kind of chlorine-free bleaching of paper pulp, metal is wherein removed with chelating agent, it is characterized in that described chelating agent is that at least one of 5-11 do not used in effective mix stages of bleaching tower and mixed with paper pulp at pH, and washing pulp in after final mix stages l5 minute.
2. the method for claim 1, its feature also are the Kappa number of the paper pulp before the chelating agent stage more than 5, perhaps described chelating agent in the stage desired metal reduction less than 60%.
3. as the described method of above-mentioned arbitrary claim, its feature is that also the total addition level of chelating agent is 0.5-3 kilogram/ton paper pulp.
4. method as claimed in claim 1 or 2, its feature are that also the temperature of chelating agent in the stage more than 75 ℃, is up to 110 ℃.
5. method as claimed in claim 1 or 2, its feature are that also the pulp density of chelating agent in the stage is 2-16%.
6. method as claimed in claim 1 or 2, its feature also are to have used two mix stages in this method at least, and chelating agent all adds in first mix stages, and mix stages subsequently only mixes again.
7. method as claimed in claim 6, its feature are that also described chelating agent adds in several mix stages.
8. method as claimed in claim 1 or 2, its feature are that also described chelating agent is EDTA type or DTPA type.
9. method as claimed in claim 1 or 2, its feature are that also described chelating agent is NTA type or DTPMP type.
10. method as claimed in claim 1 or 2, its feature also are to be undertaken described chelating agent and mixing by high-intensity blender of paper pulp, the network of fibers in this blender comminution pulp, and cause tight contact between fiber and the chelating agent.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE9700030A SE508239C2 (en) | 1997-01-03 | 1997-01-03 | Treatment of pulp with complexing agents in at least one mixing step, without the use of the bleaching tower |
| SE97000301 | 1997-01-03 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1242060A CN1242060A (en) | 2000-01-19 |
| CN1103832C true CN1103832C (en) | 2003-03-26 |
Family
ID=20405369
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN97181066A Expired - Fee Related CN1103832C (en) | 1997-01-03 | 1997-11-06 | Treatment of pulp with a chelating agent without using a bleaching tower |
Country Status (16)
| Country | Link |
|---|---|
| EP (1) | EP0951599B1 (en) |
| JP (1) | JP2001508837A (en) |
| CN (1) | CN1103832C (en) |
| AT (1) | ATE241725T1 (en) |
| AU (1) | AU726599B2 (en) |
| BR (1) | BR9714252A (en) |
| CA (1) | CA2275257A1 (en) |
| DE (1) | DE69722445T2 (en) |
| ES (1) | ES2195123T3 (en) |
| ID (1) | ID20003A (en) |
| NO (1) | NO993290L (en) |
| NZ (1) | NZ336204A (en) |
| PT (1) | PT951599E (en) |
| SE (1) | SE508239C2 (en) |
| WO (1) | WO1998029597A1 (en) |
| ZA (1) | ZA9710418B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101446054B (en) * | 2008-12-23 | 2010-04-14 | 华南理工大学 | Total-chlorine-free bleaching method of paper pulp production line with annual output of more than 50,000 tons |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1993023607A1 (en) * | 1992-05-11 | 1993-11-25 | Kamyr Ab | A process for bleaching pulp without using chlorine-containing chemicals |
| WO1994029514A1 (en) * | 1993-06-11 | 1994-12-22 | Kvaerner Pulping Technologies Ab | Ozone bleaching |
| WO1995008666A1 (en) * | 1993-09-21 | 1995-03-30 | Sunds Defibrator Industries Ab | Chlorine-free bleaching of chemical pulp involving a two stage treatment with chelating agent |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE504803C2 (en) * | 1995-08-24 | 1997-04-28 | Sunds Defibrator Ind Ab | Treatment of pulp with complexing agents in at least two mixing steps without intermediate washing |
-
1997
- 1997-01-03 SE SE9700030A patent/SE508239C2/en not_active IP Right Cessation
- 1997-11-06 WO PCT/SE1997/001853 patent/WO1998029597A1/en active IP Right Grant
- 1997-11-06 PT PT97912616T patent/PT951599E/en unknown
- 1997-11-06 NZ NZ336204A patent/NZ336204A/en unknown
- 1997-11-06 AU AU49741/97A patent/AU726599B2/en not_active Ceased
- 1997-11-06 DE DE69722445T patent/DE69722445T2/en not_active Expired - Fee Related
- 1997-11-06 CA CA002275257A patent/CA2275257A1/en not_active Abandoned
- 1997-11-06 CN CN97181066A patent/CN1103832C/en not_active Expired - Fee Related
- 1997-11-06 JP JP52990798A patent/JP2001508837A/en not_active Withdrawn
- 1997-11-06 AT AT97912616T patent/ATE241725T1/en not_active IP Right Cessation
- 1997-11-06 EP EP97912616A patent/EP0951599B1/en not_active Expired - Lifetime
- 1997-11-06 ES ES97912616T patent/ES2195123T3/en not_active Expired - Lifetime
- 1997-11-06 BR BR9714252-2A patent/BR9714252A/en not_active Application Discontinuation
- 1997-11-19 ZA ZA9710418A patent/ZA9710418B/en unknown
- 1997-12-23 ID IDP973960A patent/ID20003A/en unknown
-
1999
- 1999-07-02 NO NO993290A patent/NO993290L/en unknown
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1993023607A1 (en) * | 1992-05-11 | 1993-11-25 | Kamyr Ab | A process for bleaching pulp without using chlorine-containing chemicals |
| WO1994029514A1 (en) * | 1993-06-11 | 1994-12-22 | Kvaerner Pulping Technologies Ab | Ozone bleaching |
| WO1995008666A1 (en) * | 1993-09-21 | 1995-03-30 | Sunds Defibrator Industries Ab | Chlorine-free bleaching of chemical pulp involving a two stage treatment with chelating agent |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1242060A (en) | 2000-01-19 |
| WO1998029597A1 (en) | 1998-07-09 |
| ZA9710418B (en) | 1998-06-10 |
| DE69722445D1 (en) | 2003-07-03 |
| ID20003A (en) | 1998-09-10 |
| ATE241725T1 (en) | 2003-06-15 |
| NO993290D0 (en) | 1999-07-02 |
| SE508239C2 (en) | 1998-09-21 |
| EP0951599A1 (en) | 1999-10-27 |
| NZ336204A (en) | 1999-11-29 |
| ES2195123T3 (en) | 2003-12-01 |
| NO993290L (en) | 1999-09-02 |
| AU4974197A (en) | 1998-07-31 |
| JP2001508837A (en) | 2001-07-03 |
| SE9700030L (en) | 1998-07-04 |
| BR9714252A (en) | 2000-04-18 |
| EP0951599B1 (en) | 2003-05-28 |
| SE9700030D0 (en) | 1997-01-03 |
| AU726599B2 (en) | 2000-11-16 |
| PT951599E (en) | 2003-10-31 |
| CA2275257A1 (en) | 1998-07-09 |
| DE69722445T2 (en) | 2004-01-15 |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |