CN1075143C - Method for removal of hexenuronic acid groups in cellulose pulp by heat treatment - Google Patents
Method for removal of hexenuronic acid groups in cellulose pulp by heat treatment Download PDFInfo
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- CN1075143C CN1075143C CN95196599A CN95196599A CN1075143C CN 1075143 C CN1075143 C CN 1075143C CN 95196599 A CN95196599 A CN 95196599A CN 95196599 A CN95196599 A CN 95196599A CN 1075143 C CN1075143 C CN 1075143C
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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
- D21C9/001—Modification of pulp properties
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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
- D21C9/1005—Pretreatment of the pulp, e.g. degassing the pulp
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Abstract
Pulp, in particular hardwood pulps, is delignified in cooking is disclosed, when needed, further delignified with oxygen to a kappa number below (24), preferably below (14). The delignified pulp is heated and treated at a temperature of about 85 to 150 DEG C, preferably 90 to 110 DEG C, at a pH of about 2 to 5 in order to decrease the kappa number by 2 to 9 units by removing at least 50 % of the hexenuronic acid groups in the pulp. The treated pulp is bleached in at least one bleaching stage.
Description
The present invention relates to a kind of method of handling the cellulose pulp of claim 1.
In recent years, elemental chlorine is attempted to abandon always by pulp mill, and partly abandons chlorine dioxide, and the reason of doing like this is due to environmental protection and these two aspects of the market factor.The shortcoming that is caused by elemental chlorine comprises, not only will emit a large amount of foul gass, and will have waste liquid to enter the aqueous systems from chemical pulp factory.Chlorine dioxide mainly is to influence aqueous systems, and it can not produce the such shortcoming of foul gas on a large scale.When the AOX number of representing by the load to aqueous systems compares these chlorine chemistry agent, will find that the AOX number that elemental chlorine caused will many manyfold than chlorine dioxide.
In the period of in the past some, except that those method for bleaching that use chlorine and chlorine dioxide, many chlorine-free bleaching methods have been developed.For example, in these methods, use oxygen, ozone and peroxide.Yet, in many countries, use the bleaching schedule of chlorine dioxide still very popular, this may think still that these programs are only to environment.Popular reason is many-sided.Compare with other chemical agent, the price of chlorine dioxide has competitiveness, and for example at present the price of chlorine dioxide is about half of peroxide price of competition mutually.In addition, better by intensity and brightness value that ClO 2 bleaching is obtained, in fact, when using peroxide with identical chemical agent consumption (kg/adt), chlorine dioxide is obtained identical approximately intensity and brightness value at least.
When the bleaching of cellulose pulp based on as the bleached chemical agent of oxygen, peroxide or ozone the time, remove heavy metal and constituted main processing section.Harmful metal comprises, with manganese, copper and the iron that promotes the harmful reaction of pulp quality.These metals will make bleaching agent degraded, the consumption that this will reduce bleaching efficiency and increase chemical agent.In cellulose pulp, heavy metal mainly is bonded on the carboxylic acid group.
Proposed a kind of method that can remove metal effectively already, this method comprises, before the bleaching section of strictness, with acid for example sulfuric acid paper pulp is carried out preliminary treatment.Disclosed FI patent application 76134 (CA1206704) discloses, and at least 50 ℃, preferably carries out acid treatment under the pH value of 60-80 ℃ and 1-5.In addition, this patent application also points out, even also can remove harmful metal ion in a large number in the acid treatment of low temperature more, but carries out acid treatment with modified lignin by the temperature of this publication, the result is, alkaline peroxide after this acid treatment will improve dissolution (Lachenal, the people such as D. of lignin in handling greatly, the Tappi proceedings, international association with pulp bleaching seminar, 1982, the 145-151 pages or leaves).Therefore, the acid treatment section makes card uncle valency reduce in peroxide stage, and the reduction of not finding to have any card uncle valency in the acid treatment section.In publication FI 76134, also point out in addition, in theory, acid treatment even can carry out at 100 ℃, but this may make the pulp quality variation.
Suggestion after acid treatment, should be added with the metal ion such as the magnesium ion that are beneficial to peroxide bleaching in EP patent application 511695, and this is because also partly removed these metals in acid treatment.According to this publication, acid treatment is at 10-95 ℃, and best at 40-80 ℃ and pH1-6, the best is carried out under 2-4.This acid treatment is after the workshop section that adds suitable alkaline-earth metal.In addition, this publication also points out, in acid treatment, paper pulp can be handled with suitable bleaching and/or delignification chemical agent such as chlorine dioxide.
When using the chelating agent of using in conjunction with metal, can more effectively remove harmful metal with acid treatment.Wherein a kind of such method is disclosed in the SE patent 501651, this Patent publish with the similar acid treatment of above-mentioned EP publication 511695, different is that this acid treatment is to carry out in the presence of chelating agent.Yet, be used for will increasing the cost of bleaching in conjunction with the chelating agent of metal.
Paper pulp is carried out above-mentioned acid-treated main purpose be, obtain the metal composites of a kind of preferably chlorine-free bleaching agent.In these workshop sections, because due to washing and the extracting, card primary valency 1-2 the unit that can descend.As previously mentioned, metal component will influence the consumption of bleaching agent, thereby using the reason of known acid processing section is to remove metal from paper pulp.
It is to consume bleaching agent in a large number that prior art is bleached one of most important shortcoming, especially chlorine-free bleaching agent, and this will obviously improve the production cost of bleached pulp.For the reason of economy and environment, ClO 2 bleaching must manage to reduce the consumption of chemical agent.In addition, (will be significantly in some occasion) brightness to a certain degree is converse is a typical feature using the paper pulp of oxygen and peroxide bleaching.
Therefore, the objective of the invention is to eliminate shortcoming of the prior art or make it to minimize, and provide a kind of new method of bleached cellulose paper pulp, particularly, bleaching agent or chlorine dioxide by the totally chlorine free that still is of great importance in association with pulp bleaching prepare cellulose pulp under alkali condition.In addition, the objective of the invention is, for example by oxygen and/or the easy cellulose pulp of bleaching of peroxide production.
The plain paper pulp of known fiber contains 4-O-methyl-α-D-glucuronic acid class (glucuronic acid class).According to our nearest discovery, sulfate pulp also contains the 4-deoxidation-β-left-handed-own-4-alkene acyl pyrans glycosyl uronic acid class (hexenuronic acid class) that is bonded in a large number on the xylan except that containing the glucuronic acid class.In some paper pulp, the amount of these groups even can be widely more than known glucuronic acid class.
Have found that in association with pulp bleaching, the hexenuronic acid class will consume the bleached chemical agent of electrophilic reaction, as chlorine, chlorine dioxide, ozone and peracid (people such as Buchert, about the seminar of Europe for the third time of lignocellulose and paper pulp, Stockholm, 1994.8.28-31).Yet because the hexenuronic acid class does not react with oxygen and hydrogen peroxide, therefore, they do not influence oxygen and the hydrogen peroxide consumption that is used as bleaching agent under alkali condition.Therefore, when oxygen and/or peroxide bleaching, the degraded of hexenuronic acid class can not take place.But with regard to regard to the paper pulp of oxygen and/or peroxide bleaching, concrete problem is low relatively brightness, and/or these paper pulp have and carry out the converse trend of brightness.
According to described above, the present invention is based on following idea, that is the consumption that possible reduce bleaching agent exactly by optionally removing the hexenuronic acid class with bleaching from cellulose pulp.Surprisingly, have found that meanwhile the converse trend of brightness of pulp also will reduce.In addition, owing to can more effectively remove heavy metal, therefore, bleaching becomes more selective.
Feature of the present invention will clearly be expressed in the appending claims.
According to the present invention, it is to transfer to faintly acid (typically, the pH value is arranged between about 2 and about 5) by the water slurry with cellulose pulp that described selectivity is removed the hexenuronic acid class, and realize by treatment of aqueous suspensions at elevated temperatures.In order to obtain preferred result, temperature is at least 85 ℃, and the best is at least 90 ℃.Before, in acid treatment, avoided using high like this temperature, because think that pulp quality is with impaired.Acid-treated main purpose is to remove poisonous metal always.In above-mentioned acid treatment, its objective is and remove metal that temperature does not play significant feature.Significant is the pH value of paper pulp, and this value is low to moderate metal and can isolates from fiber.In the laboratory, this processing is normally at room temperature carried out.In the pulp mill, remove that metal normally realizes 60-85 ℃ temperature.Owing to carry out water circulation, this temperature is a natural temperature popular in the acid treatment.If for some reason, the pulp mill wishes to carry out acid treatment in higher temperature, and so, this acid treatment section will have to heat separately with steam or similar method.Owing to thought that the intensity quality of paper pulp with impaired, therefore, will avoid high temperature certainly.Therefore, according to hitherto known reason, without any reason use heat, be higher than 85 ℃ acid treatment section.Mentioned higher temperature only is meant in prior art (for example, FI 76134), also can remove metal under higher temperature.
Except the acid treatment time quite long, typically surpass 10 minutes beyond, with regard to removing metal, the described processing time does not play an important role.The extra time does not have harm to removing metal, and still, because the long process time need be used bigger container, therefore, this will cause extra cost to the pulp mill naturally.Bulk container is avoided always, also because worry that this acid treatment section can be harmful to the intensity quality of paper pulp.Therefore, the acid treatment of mentioned in the prior art long process time only is meant, can be to not removing the long process time that metal plays illeffects.
Particularly, must be pointed out, certain reason is arranged under pulp mill's condition, avoiding acid treatment long-time and heat (for example 2-3 hour and 85 ℃).These above-mentioned reasons are so important, consequently make also before the present invention not find the card uncle valency of paper pulp to be reduced 2-9 by this processing, preferably reduce 3-6 unit.Because whole notion all is considered to run counter to all existing knowledge, therefore, even laboratory experiment also fails to find the reduction of card uncle valency.Especially surprisingly, similar therewith preferably below 14 promptly below 24 if the card uncle valency of pending paper pulp is reduced significantly by boiling or possible further delignification, acid treatment can be carried out not losing under the pulp strength quality.What also must remember in addition is, in the period of nearest five, with regard to peroxide stage, to having carried out intensive detection with acid (A section) with the pulp processing of chelating agent (Q section).Thereby, pointed out that at high temperature and long-time, even the long-time and hot acid processing section when using separately is considered to the acid-treated adverse factor to paper pulp, this will be to make us very surprised and novelty more or less.
Should be noted also that the pH during known acid is handled must be quite low in order to reduce the content of manganese in the paper pulp for example in large quantities.Be lower than at 2 o'clock at pH, the carboxylic acids group will be protonated fully, and the result makes tenor become very low.When pH2-6, metal ion and hydrogen ion contention carboxylic acid position, the result is that when the pH value increases, tenor will increase (Devenyns, people such as J., Tappi Pulping Conference Proceedings, 1994,381-388; Bouchard, people such as J., International Pulp Bleaching Conference 1994,33-39).On the other hand, in the method for the invention, removed carboxylic acids group (hexenuronic acid), this will mean that the carboxylic acid position is reduced, and paper pulp will be occupied by metal with littler degree.
According to the present invention,, can produce easy bleached cellulose paper pulp by making hexenuronic acid enter sulfate process in the paper pulp or suitable alkaline process.The paper pulp that makes according to the present invention is characterised in that it contains a spot of hexenuronic acid at the most, and can easily be bleached under chlorine (ECF) or the chlorine chemistry agent (TCF) not having, or even can only just be bleached easily with oxygen and/or peroxide.Can also reduce the consumption of bleached chemical agent widely.In addition, the feature of the paper pulp of Sheng Chaning is in this way, and the converse value of brightness of the paper pulp that shows with the pc numerical table is less than 2.
Hereinafter, at least 85 ℃, in sour environment, the processing that the paper pulp in water slurry is implemented according to the present invention also is referred to as " acid preliminary treatment ".
According to the present invention,, in the presence of water,, under the pH value of about 2-about 5 (common scopes), cellulose pulp is handled at 2-5 at least 85 ℃ in order from cellulose pulp, to remove the hexenuronic acid class.Especially preferred is that the pH value of the water slurry of cellulose pulp remains between 2.5 and 4.Minimum pH value is preferably from 2.5-3.5 for needlebush, and for leaf wood the highest pH value from 3-4.
Can use various inorganic acids such as sulfuric acid, nitric acid and hydrochloric acid, and organic acid such as formic acid and/or acetate are set up the pH value of liquid paper pulp.If desired, can for example come these acid is cushioned with these sour salt such as formates, so as during to handle as much as possible with pH value held stationary.About temperature, can do bigger change in the scope more than 85 ℃.Preferably temperature is maintained at about 90-110 ℃.If this processing is carried out under condition of normal pressure, 100 ℃ is the upper limit (UL) of nature.If the working pressure container, even higher temperature also is possible.Therefore, can handle in bleaching tank 110-130 ℃ temperature at the pressure of 200-500kPa.For fear of the excessive degradation of fiber, the upper limit (UL) of this temperature is set in about 180 ℃ usually.
Processing time is according to the pH value, temperature and the material handled and change.Certainly, this also depends on the degree of removing of the hexenuronic acid that hope obtains.Usually, this processing time is at least t minute, and t=0.5exp (10517/ (T+273)-24) (t=0.5e
(10517/ (T+273)-24)).T (℃) be acid-treated temperature.The degraded of hexenuronic acid class is a first-order kinetics.Known, the pass between reaction rate constant k and the temperature T (k) is k=Ae
-E/RT(Arrhenius relation), in the formula, A is the constant that depends on described reaction, and E is an activation energy, and R is a gas constant.On the other hand, the reaction time that is known that first order reaction is t=(1/k) ln (c
0/ c), in the formula, c is the concentration of hexenuronic acid, c
0It is initial concentration.By using Arrhenius equation and t=(1/k) ln (c
0/ c) and result of the test (for example the following examples 8), obtained equation, t=0.5exp (10517/ (T+273)-24).Usually t is between 5 minutes and 10 hours.Among the described below embodiment, under normal pressure, carry out this processing.The exemplary process time at 90 ℃ is about 1.5-6 hour, and in the time of 95 ℃ about 50 minutes to 5 hours, in the time of 100 ℃ about 0.5-4 hour.Depress adding, for example when 120-130 ℃ temperature, this processing can be carried out in about 5-50 minute usually.
The objective of the invention is, remove most hexenuronic acid as much as possible, preferably at least about 50%,, optimum at least about 90% especially preferably at least about 75%." paper pulp contains a spot of hexenuronic acid at the most " means, and the hexenuronic acid amount that is present in after boiling in the undressed corresponding paper pulp is at most 50%, and especially preferred is at the most 25%, and only is at the most 10%.
In order to prevent the excessive degradation of carbohydrate, can not attempt to remove fully the hexenuronic acid class usually.
This processing can be carried out in processed continuously mode in the flow reactor of footpath, or carries out in the mode of batch process.Handle under the existence of water in the paper pulp, in other words, will wash in the water from the paper pulp that pulp cooking process obtains, to cause in preliminary treatment according to the present invention, the concentration of liquid paper pulp is about the preferably about 1-20% of 0.1-50%.Preferably under the condition of mixing, carry out preliminary treatment.When mixing continuously, can use static mixer.
According to the solution of the present invention, can be used for by paper pulp sulfate process or other alkaline process production and that contain the hexenuronic acid class.
Term " sulfate process " refers to the boiling method that main cooking chemical is vulcanized sodium and NaOH.Other alkaline boiling method comprises, for example, extends the cooking process of reducing to about extension until the card uncle valency of paper pulp at 20 o'clock based on the sulphate cook with routine.These methods generally include oxygen and handle.The boiling method that extends comprises, for example, the batch cooking of extension (+AQ), EMCC (extension, the continuously cooking of modification), batch cooking, Supe-Batch/O
2, MCC/O
2And continuously cooking/O
2According to our test, hexenuronic acid has constituted the hydrolysate of about 0.1-10 mole % that the xylan of the softwood pulp that receives from described boiling method handles.After preliminary treatment according to the present invention, the concentration of hexenuronic acid will be reduced to about 0.01-1 mole %.
In this application, term " together with bleaching " refers to, and acid preliminary treatment during bleaching, or is carried out after bleaching before bleaching at the latest.When the material with electrophilic reaction, for example, chlorine, chlorine dioxide, ozone or peracid when the bleaching agent especially preferredly is, carries out preliminary treatment before bleaching, and this is because can reduce the consumption of bleaching agent by this way.Be pointed out that also that in addition in order to change the performance of cellulose pulp, for example bleachability can be used for brown stock with this processing.On the other hand, when in bleaching (or bleaching is handled), using oxygen and/or peroxide, after bleaching, can also carry out this preliminary treatment.In a kind of occasion in back, this is handled preferably in the possible drying of paper pulp (promptly never dry) before, carries out after following bleaching closely.In addition, this preliminary treatment also can be carried out between the bleaching section of bleaching schedule.
Mentioned the example of suitable bleaching schedule below:
A-O-Z-P
AQ-O-Z-P
A-O-ZQ-P
A-O-P
n
AQ-O-P
n
O-A-Z-P
O-AQ-Z-P
O-A-ZQ-P
O-A-P
n
O-AQ-P
n
O-A-D-E-D
O-AD-E-D
A-O-D-E-D
O-A-X-P
n
Acid preliminary treatment under the temperature that A=raises according to the present invention;
O=oxygen is handled;
The P=peroxide treatment;
P
n=several peroxide treatment sections subsequently;
E=alkali treatment section;
Z=ozone treatment (ZQ refers to, and adds compounding ingredient in ozone treatment);
The Q=compounding ingredient is handled (AQ refers to, and adds compounding ingredient in acid treatment);
D=chlorine dioxide treatment (AD refers to, and does not wash between section);
The X=enzyme is handled.
Between the bleaching section of using the oxygen chemical agent, the alkali treatment section can be arranged.In order to make bleaching more effective, can use known enzyme, as cellulase, hemicellulase and ligninase (lignase).
In order to reduce the consumption of ozone and/or peracid, before oxygen or peroxide stage, or afterwards, but in chlorine dioxide stage, ozone stage or peracid section (for example formic acid or peracetic acid section) are carried out preliminary treatment of the present invention before.Because can improve the bleachability of paper pulp by this preliminary treatment, therefore, the present invention can make described bleaching agent reduce significantly, and/or does not use chlorine dioxide in bleaching, ozone or peracid.
The method of many production chemical pulps with the oxygen delignification section as back segment.This processing can be before this oxygen section, or carries out afterwards, preferably carries out after this oxygen section.At bleaching schedule is that when brightness value was ISO 88%, the consumption of chlorine dioxide had reduced 30-40% in the bleaching of hardwood pulp of O-A-D-E-D.In the bleaching of needlebush, chlorine dioxide has correspondingly reduced 10-20%.In both cases, compare with the bleaching that does not have the A section, yield remains unchanged substantially.In addition, various experiments show, under intersegmental not washing, can carry out the D section after the A section, and in other words, therefore this program becomes O-AD-E-D.
Comprising with close electric bleaching agent for example in the chlorine-free bleaching program of the bleaching section of ozone or peracid, preferably before first section Z, carry out acid treatment, and preferably carry out, from paper pulp, remove hexenuronic acid effectively so that protect to levy to deliver to the mode of paper pulp being washed before the Z section at paper pulp.Also also saved the consumption of passing through the obtained chemical agent of the inventive method thus by the ozone-depleting that hexenuronic acid (HexA) causes, can consume one gram equivalent of ozone (1eqO3/HexA) by hexenuronic acid in theory and calculate.Usually, paper pulp per ton can be saved the ozone-depleting of 1-3kg.In acid treatment, except that hexenuronic acid, formed furan derivatives will consume the ozone of double amount, therefore, after acid treatment, before the bleaching section, preferably paper pulp as far as possible effectively be washed.Every kind of above-mentioned situation also relates to all other no chlorine parent electric bleaching agent, as peracetic acid, and persulfuric acid and peroxidating molybdate.
The consumption that reduces bleaching agent by acid treatment is based on such fact, and that is exactly that when removing hexenuronic acid, the amount of active acid group is reduced in bleaching, and therefore material is still less bleached.
According to an embodiment preferred, employed main bleaching agent is the material (using hydrogen peroxide usually) that contains peroxide.Therefore, can produce the converse trend of the brightness of pulp that reaches with the pc numerical table less than 2 paper pulp.Except by removing the hexenuronic acid, all can not stop the converse trend of brightness with any other effective and efficient manner.Owing in acid treatment of the present invention, also reduced the concentration of harmful heavy metal, therefore, preferably before a P-section, carried out acid treatment.Only is that peroxide treatment is attended by the oxygen preliminary treatment.
In order to produce the paper pulp of bleaching, at first the pH value of the liquid paper pulp that will handle with oxygen is arranged on about 3-4, and the temperature of paper pulp is increased to 90-130 ℃, this temperature insulation at least 5 minutes, then, with hydrogen peroxide this paper pulp is handled under alkali condition again.Do not use hydrogen peroxide, the material that contains peroxide for example can be permonosulphuric acid or respective substance, and this material is in suitable condition (for example alkali condition) degraded down, and formation hydrogen peroxide or superoxide ion.
In order to remove the heavy metal that is bonded on the cellulose pulp, can in the presence of in conjunction with the chelating agent of heavy metal, carry out preliminary treatment of the present invention.As the example of chelating agent, that can mention has EDTA and a DTPA.Usually, the ratio that is metered into the chelating agent in the paper pulp is about 0.2% of paper pulp.Yet the acid pretreated concrete advantage of the present invention that can mention is, even is not having also to remove metal quite effectively, as described in example 10 above under the chelating agent processing.
In addition, also acid preliminary treatment can be used for brown stock or bleached pulp, to improve the characteristic relevant with paper quality.Therefore,, reduced the water amount of keeping of paper pulp, thus, can produce and be applicable to packing board for example, more stiff paper pulp by removing acidic-group.
To be described in more detail the present invention and embodiment thereof by embodiment below.
Fig. 1 has illustrated that in the time of 80 ℃ acidity is to the influence of arabinose acid groups in the pine sulfate pulp and hexenuronic acid class hydrolysis rate.Theoretical curve is suitable for the experimental point according to the equation that illustrates respectively in example 2.
Fig. 2 has illustrated from the birch kraft pulp with the acid treatment of pH3.5, removes the correlation of required time of hexenuronic acid class and 80-140 ℃ of temperature.When this pH, reaction speed is near maximum.When higher pH value, will be longer at a certain temperature the reaction time.Article three, the curve shows on top the optimum operation scope, wherein, 95,90 and 80% hexenuronic acid class is removed.The minimum in dotted line explanation reaction time wherein, has been removed 50% hexenuronic acid class.
In this embodiment, the card of paper pulp uncle valency determines that according to standard SCAN-C viscosity determines that according to SCAN-C brightness is determined according to SCAN-C at 11: 75 at 15: 88 at 1: 77.The converse trend of brightness is measured (24 hours, 105 ℃) by dry heating method.The pc number is calculated by the result of gained.
Embodiment 1
Will be from leaf wood isolated 4-O-methylglucuronic acid xylan, handled 2 hours in the caustic lye of soda of 1M at 160 ℃.With this liquid cools and by this liquid is transferred to neutrality and be settled out xylan from liquid.Washing and drying precipitated xylan then, are handled with interior zytase.The fractionation hydrolysate by using anion-exchange chromatography and gel filtration.Use this method, separate to have obtained the compound sugar cut, find by means of the NMR spectrum, this cut contains 4-deoxidation-β-left-handed-mapping--4-glycal aldehydic acid xylotriose (80%) and tetrose (20%).
The oligomeric liquid glucose of part is dissolved in the acetic acid buffer (pH3.7) of 10mM in the titanium dioxide deuterium.This liquid is put into the NMR pipe, and by at 80 ℃
1H NMR spectrum 17 hours observes variation therein.
The degraded of hexenuronic acid class is an one-level.After the reaction time 17 hours, conversion ratio was 55%.Do not find the hydrolysis of xylobiose key.When hexenuronic acid is degraded, produced the almost compound of equivalent, this compound is confirmed as furans-2-carboxylic acid (δ
H3=7.08ppm), J
H3, H4=3.5hz, J
H4, H5=1.7Hz, J
H3, H5=0.8Hz), and formic acid (δ
H=8.37ppm).In addition, also produced and be confirmed as 2-furfural-5-carboxylic acid (δ on a small quantity
H3=7.13ppm, δ
H4=7.52ppm, δ
CHO=9.60ppm, J
H3, H4=3.5hz) composition.
According to this example, hexene alditol diacid key optionally has been hydrolyzed under the condition of gentleness when the xylobiose key does not have obvious hydrolysis.Therefore, can draw as drawing a conclusion, that is exactly that Portugal's disaccharides of cellulose and glucomannan and mannobiose key are stronger than the xylobiose key of xylan, are stable under these conditions.
Embodiment 2
In different temperature (25,50 and 80 ℃) pine sulfate pulp (card uncle valency 25.9) was cultivated 2 hours in buffer solution (pH1.5-7.8).After this is handled, wash the paper pulp sample with water.With zytase the paper pulp of washing is handled, and by
1H NMR analysis of spectrum hydrolysate.
Only when using the highest temperature (80 ℃), find that just the carbohydrate component of paper pulp changes.Different with the hydrolysis of common glucoside, the hydrolysis of hexenuronic acid class is not directly proportional with hydrogen ion concentration (equation 1), but the relation of pH and reaction rate clearly illustrates that do not having hydrogen ion to carry out under the catalysis, by free hexenuronic acid class react (equation 2, Fig. 1).
(1)k=k
o[H
3O
+]
(2)k=k
o{1/(1+k
a/[H
3O
+]}
According to this example, the hexenuronic acid class in the cellulose pulp can optionally be removed under solutions of weak acidity (pH is greater than 2) at elevated temperatures.Partial hydrolysis will take place in the arabinose group, but the loss of consequent yield is inappreciable, and this is because the cause (softwood pulp 1%, hardwood pulp 0%) that the concentration of arabinose is very low in cellulose pulp.
Embodiment 3
With oligomeric liquid glucose (15.5mg, 0.025mmol) add the 0.01M of boiling the formates buffer solution (pH3.3,27ml) in.This liquid was refluxed 3 hours.Take out sample (0.5ml) and water (5ml) dilution with proper spacing.The absorption of measuring light in the wave-length coverage of 200-500nm.Furans-2-carboxylic acid (the λ that forms
Max=250nm) with one-level (k=0.44h
-1) consistent.The molar absorption coefficient that every part of hexenuronic acid class calculates is 8700.This absorptivity can be used to determine the concentration of hexenuronic acid in the cellulose pulp.
Embodiment 4
In oligosaccharide mixture (2.0mg, 3.22 μ mol) water-soluble (4.8ml).Again the sulfuric acid of 0.6ml 2M and the potassium permanganate (12.0ml) of 0.6ml 0.02M are added in this liquid.After ten minutes, KI and the 100ml water of 0.12ml 1M is added in this liquid.The concentration of iodine is determined the consumption that (350nm, ∈=16,660) calculate permanganate according to equation 3 with spectrophotometric method in the liquid.
(3)2MnO
4 -+10I
-+16H
+-＞2Mn
2++5I
2+8H
2O
The consumption of permanganate is 7.98 μ mol, promptly is calculated as 2.5 with every gram equivalent of hexenuronic acid class.Owing to be under identical reaction condition, determine to be used for representing the card uncle valency of lignin concentration in the cellulose pulp, therefore, for actual lignin concentration, the hexenuronic acid class may cause sizable error.
Embodiment 5
0.06M formates buffer solution (pH3.2,250ml) in 100 ℃, birch kraft pulp (3g, card uncle valency 16.5) was handled 4 hours.Observed the degraded of hexenuronic acid class by the light absorption that causes by 2-furans-carboxylic acid (250nm, ∈=8,700).The total amount that calculates the hexenuronic acid class is 70 milliequivalents/kg paper pulp.The card uncle valency of the paper pulp of handling is 10.6.
According to the present invention,, therefore, can from sulfate pulp, remove a large amount of hexenuronic acid classes owing to be used for representing that the card uncle valency of delignification grade obviously descends.With the consumption of the close electric bleaching agent of hexenuronic acid class reaction, expection can take place similarly to reduce.
Embodiment 6
0.06M formates buffer solution (pH3.2,600ml) in 100 ℃, to handling 2.5 hours with the pine sulfate pulp of oxygen and peroxide bleaching (9g, card uncle valency 5.3).Observed the degraded of hexenuronic acid class by the light absorption that causes by 2-furans-carboxylic acid (250nm, ∈=8,700).
The total amount that calculates the hexenuronic acid class is 48 milliequivalents/kg paper pulp.All hexenuronic acid classes all were removed in about 30 minutes reaction time.The paper pulp that filtration treatment is crossed in the Buchner funnel, and water washs.Compare with original paper pulp, the paper pulp of handling is easy to infiltration.The card uncle valency of the paper pulp of handling is 2.3.
After the processing of removing the hexenuronic acid class, the card uncle valency according to the present invention with the sulfate pulp of oxygen and peroxide bleaching is very low.According to the present invention, do not having under the ozone bleaching, obviously improved and produced the possibility of floating the TCF slurry entirely.
Embodiment 7
To in water (31), mix with the birch kraft pulp (100g, card uncle valency 11.5) that oxygen bleaching is crossed.By adding the dense formic acid of 2ml the pH of this suspension is transferred to 3.4.The suspension of producing was in this way cultivated 4 hours at 100 ℃.Observed the degraded of hexenuronic acid class by the light absorption that causes by 2-furans-carboxylic acid (250nm, ∈=8,700).The total amount that calculates the hexenuronic acid class that is removed is 54 milliequivalents/kg paper pulp.This amount is about 98% of hexenuronic acid class total amount in the paper pulp.The card uncle valency of the paper pulp of handling is 6.2.
With EDTA (paper pulp 0.2%) and that handled and untreated concentration is that 3.5% paper pulp carries out chelating.This chelation treatment is carried out at 60 ℃, and its processing time is 45 minutes.
After the washing, be that 10% paper pulp carries out peroxide bleaching (amount of hydrogen peroxide be paper pulp amount 3%) to concentration.With magnesium sulfate (paper pulp amount 0.5%) used as stabilizers, as alkali, temperature is 90C to NaOH (paper pulp amount 1.8%), and bleaching time is 180 minutes.Then, determine the card uncle valency of washed paper pulp, viscosity, the converse trend of brightness and brightness (pc number).The characteristic of paper pulp is shown in table 1.Table 1. expression preliminary treatment (A) is to the section of the influence remnants H of peroxide (P) bleachability of the birch kraft pulp bleach with oxygen (O)
2O
2(% paper pulp) card uncle valency viscosity (ml/g) brightness (%ISO) pc counts O 11.5 1165 49.7OP 0 9.3 1,125 61.0 2.5OA 6.2 1065 49.9OAP 2.1 3.2 980 76.1 1.1
The result shows that preliminary treatment is very big to the effect of paper pulp peroxide stage.The consumption of peroxide obviously reduces, and in addition, does not compare with having treated paper pulp, and the rising of brightness is greater than more than the twice.The converse trend of brightness of the pretreating paper pulp that shows with the pc numerical table is compared with the converse trend of the brightness that does not have treated paper pulp, be lower than 50%.
Embodiment 8
Being that 5% formic acid is not handled bleaching birch kraft pulp (card uncle valency 15.4) with concentration, is 3.0,3.5 or 4.0 with the pH that causes slurries.Then, will in the pressure vessel of 150ml, cultivate 0.2-24 hour with the paper pulp that the method is handled in 85,95,105 and 115 ℃.By the concentration of the furan derivatives of hexenuronic acid class formation in definite filtrate, and the degraded of observation hexenuronic acid class.Then, the card of definite paper pulp of cultivating uncle's valency and viscosity.
The reduction of card uncle valency is relevant with the reduction of hexenuronic acid concentration, and linear.At utmost the hexenuronic acid concentration of Jiang Diing is 60meq/kg, and corresponding card uncle valency is reduced to 6.3 units.The rate of removing of hexenuronic acid is 90%, and treatment effeciency is as the criterion with TOC and is calculated as 98%.The degraded of hexenuronic acid class is consistent with first-order kinetics.By being described the required minimum time of staying of this processing (hexenuronic acid concentration reduce by 50%) with the corresponding to curve of experimental point (Fig. 2), and most optimal retention time (hexenuronic acid concentration reduces 80-95%).The degradation speed of hexenuronic acid class approaches its maximum when pH3.0-3.5.When higher pH value,, therefore need the longer time of staying because reaction speed is slower.
Embodiment 9
Under condition, the birch kraft pulp (card uncle valency 10.3) with oxygen bleaching is handled, to remove the hexenuronic acid class according to embodiment 8.Card uncle valency after the processing is 5.4.Use the chlorine dioxide and the alkali of some kinds of dosage, the paper pulp and the undressed paper pulp of acid treatment are bleached with the DED program.When bleaching to 88.0%ISO brightness, the chlorine dioxide (in active chlorine) of the paper pulp of acid treatment consumption 2.5% and 1.4% NaOH.And undressed paper pulp correspondingly will consume 4.3% chlorine dioxide and 0.8% NaOH respectively.For the paper pulp of acid treatment, the yield of DED program is 97.1%, and the yield of the paper pulp of unprocessed mistake is 95.5%.Therefore, do not reducing under the bleaching interest rate, removing the chemical agent minimizing 42-43% that the hexenuronic acid class makes the ECF bleach consumption.Under identical paper density, the tensile index of the paper that is made by these two kinds of paper pulp is identical with tear index.
Embodiment 10
In water (31), mix pine sulfate pulp (100g, card uncle valency 25.9).Dense formic acid by adding 1.5ml transfers to 3.5 with the pH of this suspension.The suspension of producing was in this way cultivated 2.5 hours at 100 ℃.Observed the degraded of hexenuronic acid class by the light absorption that causes by 2-furans-carboxylic acid (250nm, ∈=8,700).The total amount that calculates the hexenuronic acid class that is removed is 32 milliequivalents/kg paper pulp.This amount is about 95% of hexenuronic acid class total amount in the paper pulp.With EDTA (paper pulp 0.2%) and that handled and untreated concentration is that 3% paper pulp carries out chelating.This chelation treatment is carried out at 50 ℃, and its processing time is 45 minutes.The metal concentration of paper pulp is determined with atomic absorption spectrophotometer.
The processing of removing the hexenuronic acid class has especially reduced the concentration (table 2) of iron and manganese in the paper pulp.In this occasion, the minimizing of iron is obviously handled greater than the use chelating agent, even the minimizing of manganese also can nearly use the chelating agent processing so much.
Table 2 shows that preliminary treatment (A) and chelation (Q) handle iron copper manganese to the effect of pine sulfate pulp metal concentration (mg/kg)
22.0 6.5 36.8A 10.7 5.7 2.4Q 20.9 0.9 1.8AQ 10.4 1.3 0.2
With regard to TCF bleaching, because iron and manganese are the most harmful metals, therefore, can be with the processing section of removing hexenuronic acid or replace using chelating agent fully.If the use chelating agent preferably adds chelating agent with the processing of removing the hexenuronic acid class.
Although the present invention is with thinking most realistic being described with embodiment preferred at present, should be understood that, the present invention is not limited to disclosed embodiment, on the contrary, regulation the present invention includes the various improvement included in the spirit and scope of the appended claims and the scheme of equivalence.
Claims (15)
1. the processing method of a cellulose pulp that makes by alkaline process, the card uncle valency of described paper pulp is less than 24, it is characterized in that, at about 85-150 ℃, pH is about, and 2-5 handles cellulose pulp, and the time of processing will be enough to remove in the cellulose pulp at least 50% hexenuronic acid class, and makes the card uncle valency of this paper pulp reduce 2-9 unit, the described time is between 5 minutes and 10 hours, and t=0.5e at least
(10517/ (T+273)-24), with minute the expression, in the formula, T be acid-treated treatment temperature (℃), processed paper pulp obtain the bleaching.
2. according to the method for claim 1, it is characterized in that, carry out in the bleaching schedule of this processing before chlorine dioxide stage, the consumption of chlorine dioxide when bleaching to reduce.
3. according to the method for claim 2, it is characterized in that, under the situation that does not have washing between the section, the paper pulp of acid treatment is bleached with chlorine dioxide.
4. according to the method for claim 1, it is characterized in that, carry out in the bleaching schedule of this processing before ozone stage, the consumption of ozone when bleaching to reduce.
5. according to the method for claim 4, it is characterized in that the paper pulp to acid treatment before the ozone bleaching section washs.
6. according to the method for claim 1, it is characterized in that, carry out in the bleaching schedule of this processing before the peracid section, the consumption of peracid when bleaching to reduce.
7. according to the method for claim 6, it is characterized in that the paper pulp to acid treatment before crossing the acid blanching section washs.
8. according to the method for claim 1, it is characterized in that, wash and bleach with the paper pulp of no chlorine parent electrochemistry agent to acid treatment.
9. according to the method for claim 1, it is characterized in that this was handled before oxygen or peroxide stage, or carried out in the bleaching schedule afterwards, produced bleached pulp, its converse trend of brightness of showing with the pc numerical table is less than 2.
10. according to the method for claim 1, it is characterized in that this processing is carried out under the concentration of 0.1-50%.
11. the method according to claim 1 is characterized in that, this processing is carried out at the about 2.5-4 of pH.
12. the method according to claim 1 is characterized in that, by inorganic or organic acid and set up the pH value of cellulose pulp.
13. the method according to claim 1 is characterized in that, with oxygen cellulose pulp is handled before this processing.
14. the method according to claim 1 is characterized in that, temperature is 90-110 ℃.
15. the method according to claim 1 is characterized in that, carries out acid treatment in proper order with following bleaching:
A-O-Z-P
AQ-O-Z-P
A-O-ZQ-P
A-O-P
n
AQ-O-P
n
O-A-Z-P
O-AQ-Z-P
O-A-ZQ-P
O-A-P
n
O-AQ-P
n
O-A-D-E-D
O-AD-E-D
A-O-D-E-D
O-A-X-P
n
Acid preliminary treatment under the temperature that A=raises according to the present invention;
O=oxygen is handled;
The P=peroxide treatment;
P
n=several peroxide treatment sections subsequently;
E=alkali treatment section;
Z=ozone treatment (ZQ refers to, and adds compounding ingredient in ozone treatment);
The Q=compounding ingredient is handled (AQ refers to, and adds compounding ingredient in acid treatment);
D=chlorine dioxide treatment (AD refers to, and does not wash between section);
The X=enzyme is handled.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FI944808A FI102301B (en) | 1994-10-13 | 1994-10-13 | Method for treating cellulosic pulps |
| FI944808 | 1994-10-13 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1168706A CN1168706A (en) | 1997-12-24 |
| CN1075143C true CN1075143C (en) | 2001-11-21 |
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| CN95196599A Expired - Lifetime CN1075143C (en) | 1994-10-13 | 1995-10-12 | Method for removal of hexenuronic acid groups in cellulose pulp by heat treatment |
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| Country | Link |
|---|---|
| EP (1) | EP0786029B1 (en) |
| CN (1) | CN1075143C (en) |
| AU (1) | AU3655995A (en) |
| CA (1) | CA2160430C (en) |
| DE (1) | DE69517532D1 (en) |
| ES (1) | ES2147303T3 (en) |
| FI (2) | FI102301B (en) |
| NO (1) | NO971682L (en) |
| NZ (1) | NZ293983A (en) |
| PT (1) | PT786029E (en) |
| RU (1) | RU2126862C1 (en) |
| SE (1) | SE518080C2 (en) |
| WO (1) | WO1996012063A1 (en) |
| ZA (1) | ZA958655B (en) |
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| FI105701B (en) * | 1995-10-20 | 2000-09-29 | Ahlstrom Machinery Oy | Method and arrangement for treatment of pulp |
| US6306334B1 (en) | 1996-08-23 | 2001-10-23 | The Weyerhaeuser Company | Process for melt blowing continuous lyocell fibers |
| US6235392B1 (en) | 1996-08-23 | 2001-05-22 | Weyerhaeuser Company | Lyocell fibers and process for their preparation |
| US6331354B1 (en) | 1996-08-23 | 2001-12-18 | Weyerhaeuser Company | Alkaline pulp having low average degree of polymerization values and method of producing the same |
| US6605350B1 (en) | 1996-08-23 | 2003-08-12 | Weyerhaeuser Company | Sawdust alkaline pulp having low average degree of polymerization values and method of producing the same |
| US6210801B1 (en) | 1996-08-23 | 2001-04-03 | Weyerhaeuser Company | Lyocell fibers, and compositions for making same |
| US6221487B1 (en) | 1996-08-23 | 2001-04-24 | The Weyerhauser Company | Lyocell fibers having enhanced CV properties |
| BE1010677A3 (en) * | 1996-10-11 | 1998-11-03 | Solvay Interox | Method for the delignification and bleaching of a chemical paper pulp |
| BE1010880A3 (en) * | 1997-01-27 | 1999-02-02 | Solvay Interox | Process for producing pulp chemicals. |
| FI122654B (en) * | 1997-12-08 | 2012-05-15 | Ovivo Luxembourg Sarl | Process for making paper cellulose pulp |
| FI119383B (en) * | 1998-03-06 | 2008-10-31 | Andritz Oy | Procedure for treating pulp |
| US6686039B2 (en) | 1999-02-24 | 2004-02-03 | Weyerhaeuser Company | Use of thinnings and other low specific gravity wood for lyocell pulps |
| US6685856B2 (en) | 1999-02-24 | 2004-02-03 | Weyerhaeuser Company | Use of thinnings and other low specific gravity wood for lyocell products method |
| US6797113B2 (en) | 1999-02-24 | 2004-09-28 | Weyerhaeuser Company | Use of thinnings and other low specific gravity wood for lyocell pulps method |
| US6686040B2 (en) | 1999-02-24 | 2004-02-03 | Weyerhaeuser Company | Use of thinnings and other low specific gravity wood for lyocell products |
| AU5317700A (en) * | 1999-06-08 | 2000-12-28 | Eastern Pulp And Paper Corporation | Bleaching pulp with high-pressure O2 |
| SE0002047L (en) * | 2000-05-31 | 2001-11-19 | Kvaerner Pulping Tech | Process for controlling a process for making pulp by optical measurement of the amount of hexenuronic acid |
| JP4603298B2 (en) * | 2004-06-08 | 2010-12-22 | 日本製紙株式会社 | Pulp bleaching method |
| US20060201642A1 (en) * | 2005-03-08 | 2006-09-14 | Andritz Inc. | Methods of treating chemical cellulose pulp |
| US20070240837A1 (en) * | 2006-04-13 | 2007-10-18 | Andritz Inc. | Hardwood alkaline pulping processes and systems |
| US8262856B2 (en) | 2007-06-18 | 2012-09-11 | Andritz Inc. | Processes and systems for the bleaching of lignocellulosic pulps following cooking with soda and anthraquinone |
| ZA200805042B (en) * | 2007-06-18 | 2009-09-30 | Andritz Inc | Processes and systems for the bleaching of lignocellulosic pulps following cooking with soda and anthraquinone |
| CN102995478B (en) * | 2011-09-09 | 2015-04-15 | 吉林化纤集团有限责任公司 | Bleaching method for preparing high quality low pollution bamboo wood dissolving slurry |
| FI123926B (en) | 2012-04-03 | 2013-12-13 | Upm Kymmene Corp | Method for bleaching pulp |
| JP6483021B2 (en) * | 2013-09-11 | 2019-03-13 | 日本製紙株式会社 | Method for producing dissolved kraft pulp |
| US20150184338A1 (en) | 2013-12-31 | 2015-07-02 | Weyerhaeuser Nr Company | Treated kraft pulp compositions and methods of making the same |
| CN104404807A (en) * | 2014-09-23 | 2015-03-11 | 广西大学 | Method for reducing AOX forming amount in chlorine dioxide bleaching process of bagasse pulp |
| FI128736B (en) * | 2018-03-09 | 2020-11-13 | Valmet Automation Oy | Method and measurement apparatus for measuring suspension |
| CN110258160A (en) * | 2019-07-23 | 2019-09-20 | 广西大学 | A kind of efficient high temperature chlorine dioxide pulp method for bleaching of energy-saving safe and bleaching system |
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| FI89613C (en) * | 1991-12-05 | 1993-10-25 | Valtion Teknillinen | Process for enzymatic treatment of cellulose pulp |
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- 1995-10-12 RU RU97107353A patent/RU2126862C1/en active
- 1995-10-12 CN CN95196599A patent/CN1075143C/en not_active Expired - Lifetime
- 1995-10-12 EP EP95934164A patent/EP0786029B1/en not_active Revoked
- 1995-10-12 AU AU36559/95A patent/AU3655995A/en not_active Abandoned
- 1995-10-12 ES ES95934164T patent/ES2147303T3/en not_active Expired - Lifetime
- 1995-10-12 WO PCT/FI1995/000566 patent/WO1996012063A1/en not_active Application Discontinuation
- 1995-10-12 DE DE69517532T patent/DE69517532D1/en not_active Expired - Lifetime
- 1995-10-13 ZA ZA958655A patent/ZA958655B/en unknown
- 1995-10-13 SE SE9503595A patent/SE518080C2/en not_active IP Right Cessation
-
1997
- 1997-04-10 FI FI971508A patent/FI971508A0/en unknown
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| US5143580A (en) * | 1990-04-23 | 1992-09-01 | Eka Nobel Ab | Process for reducing the amount of halogenated organic compounds in spent liquor from a peroxide-halogen bleaching sequence |
| CA2067296A1 (en) * | 1991-04-30 | 1992-10-31 | Lennart Andersson | Process for bleaching of lignocellulose-containing pulp |
Also Published As
| Publication number | Publication date |
|---|---|
| FI102301B1 (en) | 1998-11-13 |
| CA2160430A1 (en) | 1996-04-14 |
| DE69517532D1 (en) | 2000-07-20 |
| SE9503595L (en) | 1996-04-14 |
| WO1996012063A1 (en) | 1996-04-25 |
| AU3655995A (en) | 1996-05-06 |
| FI944808A0 (en) | 1994-10-13 |
| FI944808A (en) | 1996-04-14 |
| SE9503595D0 (en) | 1995-10-13 |
| NO971682L (en) | 1997-06-11 |
| RU2126862C1 (en) | 1999-02-27 |
| JPH10508346A (en) | 1998-08-18 |
| EP0786029A1 (en) | 1997-07-30 |
| ES2147303T3 (en) | 2000-09-01 |
| FI102301B (en) | 1998-11-13 |
| SE518080C2 (en) | 2002-08-20 |
| PT786029E (en) | 2000-09-29 |
| FI971508A (en) | 1997-04-10 |
| FI971508A0 (en) | 1997-04-10 |
| CA2160430C (en) | 2004-12-07 |
| NO971682D0 (en) | 1997-04-11 |
| CN1168706A (en) | 1997-12-24 |
| EP0786029B1 (en) | 2000-06-14 |
| NZ293983A (en) | 1999-04-29 |
| ZA958655B (en) | 1996-05-13 |
| JP3534412B2 (en) | 2004-06-07 |
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