CN1176673A

CN1176673A - Peroxide bleaching process for cellulosic and lignocellulosic material

Info

Publication number: CN1176673A
Application number: CN95194090A
Authority: CN
Inventors: 莱维斯·D·沙克福德; 威廉·J·米勒; 布赖恩·P·罗伊; 巴巴拉·范莱罗普; 理查德·M·贝里
Original assignee: Canadian Pulp And Paper Research Institute; Ingersoll Rand Co
Current assignee: Canadian Pulp And Paper Research Institute; Ingersoll Rand Co
Priority date: 1994-07-11
Filing date: 1995-06-29
Publication date: 1998-03-18
Also published as: EP0797703A1; PT797703E; EP0919661A1; WO1996001920A1; DE69515066D1; BR9508388A; DE797703T1; FI970104A0; ES2107399T3; CA2194880A1; RU2141016C1; DE69515066T2; JP2787618B2; ZA955290B; EP0797703B1; ES2107399T1; JPH09508945A; FI970104A; ATE189716T1

Abstract

A method for bleaching cellulosic and lignocellulosic pulp using hydrogen peroxide as a bleaching reagent, utilizes a two-step reaction, viz. a short high temperature step at a pressure sufficient to suppress boiling and a longer atmospheric pressure reduced temperature step to consume a substantial portion of the hydrogen peroxide remaining after the short phase. The method includes the steps of introducing pulp (15), at a consistency of 10 %-18 %, to a mixer (100) in which the pulp is heated to a temperature above 100 DEG C; adding sufficient sodium hydroxide to bring the pulp to a pH of 8.5; adding sufficient hydrogen peroxide (36) to equal from about 0.5 %-5.0 %, by weight, of the pulp; passing the pulp through a pressurized reactor column (400) at a rate providing a reaction time in the column of between 1 and 30 minutes; and depositing the pulp in a reaction tower and allowing the reaction to proceed for 1-5 hours until a substantial portion of the residual hydrogen peroxide has been consumed. It may be desirable to introduce the pulp to a mixer and add alkali to reactivate residual hydrogen peroxide by bringing the pulp to a pH of at least 9 between bleaching steps.

Description

The peroxide bleaching process of cellulosic material and ligno-cellulosic materials

In general, the present invention relates to the bleaching of ligno-cellulosic materials in the pulp and paper industry, particularly relate to the method for improving the association with pulp bleaching program feature that uses hydrogen peroxide.When being used in combination with the bleaching schedule that designs for the pulp production of not using the chlorine compound bleaching, this method is valuable especially.

Owing to from pulp bleaching process, remove chlorinated compound and reduce their due to pressure, the tide that had evoked what is called " no chlorine technology " already to the negative effect of environment.When chlorine compound is removed from bleaching schedule, owing to it is believed that hydrogen peroxide is gentle to environment usually, therefore, usually uses hydrogen peroxide thing as an alternative.Yet,, therefore, press for and develop the more efficient methods of using hydrogen peroxide, so that bleach more economical and effective because the use of hydrogen peroxide increases day by day.

Hydrogen peroxide is to be usually used in mechanical pulp, semi-mechanical pulp, the oxidizing chemical that semi-chemical pulp and reuse paper pulp brighten.In addition, it also is used to the bleaching of chemical pulp, to help delignification.

Canada pulping and paper-making (the The Pulp ﹠amp of research institute; Paper Research Institute ofCanada) (PAPRICAN) developed the method for some kinds of bleached mechanical pulps.In these methods, make the disclosed high temperature peroxide systems of people such as the interested Lierbergott of being of people, this be because, this system has been carried out and the identical improved whiteness of conventional high concentration bleach system, and in also be so when dense (10-14%).This can rise to about 85 ℃ and reduce pH value and realize by the temperature with paper pulp, and this is different with conventional high dense peroxide systems.Because reaction is accelerated, therefore, the time of staying (retentiontime) will be reduced to some minutes (15-30 minute) from some hrs, and, need not to come stable peroxide thing solution with silicate.The consumption of peroxide roughly keeps identical with the system of routine.

According to Bottan, the application of awaiting the reply of G. has proposed to carry out the very high temperature peroxide systems of short period operation at 85-95 ℃.But going back nobody proposes to be heated to paper pulp overheated and to add the time of staying execution peroxide stage of depressing with short above 100 ℃.When the brightness that keeps obtaining with usefulness very long residence time was identical, in order to make required fund input minimum, it was desirable making time of staying of paper pulp become minimum.

Dominique Lachenal of the Centre Technique du papier in Grenoble, France has proposed the residue peroxide of reactivation is used for the bleaching of mechanical pulp.This makes the peroxide (after first section reaction tower) that does not consume (or residue) by increasing the alkalescence energy reactivation of pulp suspension.Its objective is that save and usually use, expensive dehydration equipment, this equipment be to be used for reclaiming remaining peroxide and it is recycled to the position (the normally mixer place before the bleaching tower) of adding fresh peroxide behind bleaching tower.When and between section and section, need expensive dehydration equipment, when conventional two sections peroxide bleaching systems were compared, this suggestion was very important.Before residue peroxide reactivation, first section is reflected in the conventional tower and carries out some hrs in 60 ℃.Then, add NaOH, its consumption is directly proportional with the surplus of the peroxide that obtains behind 60 ℃ of reaction some hrs.

In chemical pulp, hydrogen peroxide is mainly used in middle concentration system, wherein, will dewater thickener or in the wash engine to about 10-14% concentration from the slurries that leading portion comes.Usually, peroxide solutions with alkali pulper place (from the discharging of thickener or wash engine) or add in middle concentration pump before the concentration tower or the mixer.

When the bleaching of chemical pulp was carried out with one section, dense peroxide bleaching section can not provide enough brightness to increase in the routine, and, allegedly to consume more peroxide, and need the very long time of staying with consuming peroxide.In order to carry out delignification or increase brightness more significantly, peroxide must add in several towers.

Showed already, and greater than 25% concentration the time, used high dense peroxide operation can overcome the many restrictions in the dense peroxide bleaching section in the routine.Yet its shortcoming is, needs the dewater unit that can carry out high discharging concentration is installed, operate more complicated, and the more power of dense system consumption in comparing.

For chemical pulp, extensively deoxygenation also uses peroxide that oxidation extracting section is strengthened outward, to reduce required chlorine dosage in the first association with pulp bleaching section.Conventional Eop (with the oxidation extracting of peroxide enhancing) uses up-flow/downflow tower usually, needs to use oxygen, and operates at 65-85 ℃ usually.

Back segment at association with pulp bleaching also uses hydrogen peroxide, to obtain high brightness, stable bleached pulp.May degrade owing to it is believed that peroxide, cause the utilization rate of bleached chemical agent extreme difference, the intensity of paper pulp reduces, and makes the economy of bleaching become very poor, therefore, uses its temperature of hydrogen peroxide to be usually less than 90 ℃ in the bleaching of paper pulp.

In recent years, when last use,, proposed under high temperature and the condition of the relative time of staying of growing, to use hydrogen peroxide as developing very a kind of means of high brightness paper pulp at routine or free from chloride bleaching schedule.According to prior art, the required time of staying is 1-3 hour.Showed already that the pressurised oxygen peroxide systems of long residence time can increase the brightness ceiling of paper pulp, and this ceiling surpasses the ceiling of using conventional normal pressure peroxide bleaching section to be obtained.In order to reduce the required fund input of device, it is desirable making the required time of staying minimum under pressure.For example,, show, use 100+ ℃ to carry out to reduce the required time of peroxide bleaching process effectively in 1-3 hour in the laboratory according to prior art.Even so, but because the required fund of 1-3 hour pressurized peroxide section is quite high, as if therefore, the economy of this method does not have attraction.

According to the normal pressure peroxide bleaching section of routine of the prior art and the essential information of pressurised oxygen peroxide bleaching section (PO) economy, for the single stage bleaching of about 850madtpd capacity, the pointed required input of retention tower (retention tower) of prior art is calculated as follows:

A. stop 2 hours pressurized peroxide Ta $1,000,000

B. conventional, long residence time and normal pressure section

1. stop 3 Xiao Shi $300,000

2. stop 6 Xiao Shi $400,000

3. stop 9 Xiao Shi $550,000

In order to obtain identical brightness value with conventional normal pressure peroxide bleaching, to compare with 1-3 hour of the pressurised oxygen peroxide systems of prior art, its time of staying must be above 6 hours.For example, the size of atmospheric tower must be fixed on 8-10 hour the time of staying, with the oxygen peroxide systems similar result of acquisition with 2 hours pressurization.

Only with regard to bleaching factory of North America 350 family, if in each factory, only need a peroxide bleaching system, so, with the industrial input of needs about 1,000,000.In order to satisfy the environmental legislation of increasingly stringent, the peroxide bleaching section more than must be installed in each factory, this may have the investment more than twice.Therefore, an important disadvantages of prior art is according to the technology of prior art, carry out this technology, fund input that need be a large amount of.

Foregoing has illustrated the deficiency that exists in some existing cellulose and the lignocellulose method for bleaching, therefore, advantageously, provides a kind of or multinomial replacement method that can overcome these deficiencies.Therefore, provided a kind of replacement method that is included in the feature that below will more describe in detail already.

An aspect of of the present present invention, a kind of method of using hydrogen peroxide that cellulose and lignocellulose pulp are bleached is provided, this method comprises the steps: the dense 10-18% of transferring to of slurry and this paper pulp is added in the mixer, thereby add NaOH in this mixer the pH value of paper pulp transferred to greater than 8.5; Add hydrogen peroxide, its consumption is the 0.5-5.0% of paper pulp weight; The temperature of paper pulp is heated to greater than 100 ℃, meanwhile keeps enough pressure to prevent the slurries boiling; By a reaction tower, its through-rate is less than 45 minutes with the reaction time in reaction tower and is as the criterion with paper pulp; The temperature of paper pulp is cooled to is lower than 100 ℃; Under normal pressure in reaction tower the described paper pulp of deposition and allow reaction be performed until most remaining hydrogen peroxide and all run out of till; Draw off paper pulp in order to further handling.

When considering together in conjunction with the accompanying drawings, according to following detailed description, foregoing and others of the present invention will become very clear.

Fig. 1 shows a preferred embodiment of the present invention;

Fig. 2 shows another preferred embodiment of the present invention;

Fig. 3 shows another preferred embodiment of the present invention;

Fig. 4 shows another preferred embodiment of the present invention;

Fig. 5 shows the bleaching section in conjunction with another preferred embodiment of the present invention;

Fig. 6 shows another preferred embodiment with the bleaching schedule that extremely has bleaching factory now with the present invention;

Fig. 7 shows the residue peroxide that utilizes conventional wash engine to reclaim, and uses another embodiment preferred of bleaching schedule of the present invention;

Fig. 8 shows the residue peroxide that utilizes squeezer to reclaim, and uses another embodiment preferred of bleaching schedule of the present invention;

Fig. 9 shows the other method of utilizing squeezer to reclaim the residue peroxide, uses another embodiment preferred of bleaching schedule of the present invention.

With reference to figure 1, the paper pulp that will come from the wash engine of routine or thickener is packed into by slurry pipe 10 blender 100, at this place, adds the steam that the heating paper pulp use and the alkali that increase paper pulp PH by managing 15. Transfer to greater than 8.5 with the paper pulp heating and with PH, preferably at 9.5-10.5. Then, by managing 20, with the paper pulp that heated and regulate PH from blender 100 deliver to conventional in the dense pump 200, this pump by pipe 30 with pulp pump to blender 300. By managing 35 hydrogenperoxide steam generator added in the blender 300, its consumption is to be enough to guaranteeing that can obtain desirable brightness increase when reaction finishes is as the criterion. The same with the peroxide bleaching system of routine; also can be by pipe 15 with aqueous slkali, by managing 35 with peroxide solutions, or individually by pipe 16 and/or 36; add the magnesium compound of protection cellulose viscosity, and sequestering agent is (such as SiO₂) and/or chelating agent (such as EDTA or DTPA). Because according to the present invention, the temperature of paper pulp must be above 100 ℃, and be not practicable usually at this temperature pumping paper pulp, therefore, final temperature from for example 85-90 ℃ be warming up to and surpass 100 ℃ by between pump 200 and blender 300, adding steam and realize by managing 37.

Then, the paper pulp that is heated to desirable reaction temperature and is adjusted to desirable PH is pumped in the up-flow tube type tower 400 by managing 40, the size of this tower fixes on to be had a desirable time of staying of reaction and is as the criterion. According to the present invention, it is 1-30 minute that the size of upspout is fixed on the time of staying that guarantees paper pulp, is preferably 5-20 minute, then, by managing 50 paper pulp delivered to suitable device for discharging 500, such as valve, subsequently, deliver to the washing of back and bleach section by managing 60. Because paper pulp is being bleached greater than 100 ℃, therefore, reducing this temperature is desirable with " flash distillation " that prevents paper pulp, and the water of available lower temperature or liquid dilute by managing 70 tops that enter upspout. Those skilled in the art will know that in order to obtain to react the desirable time of staying, the present invention can use up-flow, falls stream, up-flow/fall stream, or other configuration is implemented. In addition, those skilled in the art also will know, before reaction and afterwards, and the servicing unit that has respectively heating and cooling paper pulp to use. The details that provides in explanation of the present invention is not to limit the scope of the invention, but for preferred embodiment clearly is described.

Except that having increased downflow tower 600, Fig. 2 has described same as shown in Figure 1 briefly, another embodiment preferred of the present invention.According to the present invention, it is 1-30 minute that the size of upspout is fixed on the time of staying that guarantees paper pulp, be preferably 5-20 minute, then, by managing 50 paper pulp delivered to suitable device for discharging 500,, deliver to conventional bleaching tower 600 by managing 60 as valve, this bleaching tower is preferably mounted in slurry factory, and can substitute based on the bleaching schedule of chlorine and be reused for this new bleaching section.Reaction temperature in hope stopped paper pulp in this tower 1-5 hour again, added to hydrogen peroxide in the paper pulp to consume the overwhelming majority.Because paper pulp bleaching greater than 100 ℃, therefore, reduces this temperature to prevent that paper pulp " flash distillation " from being desirable in tower 400.In the present invention, can before the upspout discharging, cool off, make that slurries can " flash distillation " paper pulp.May escape to atmosphere in order to limit steam and remaining chemical agent, the present embodiment may be desirable in some slurry factory.This can be by adding cooling waters or liquid and paper pulp is diluted realize by managing 70.For example, for in the upflow tower with 12% concentration for 110 ℃ of paper pulp of handling, add the liquid of 1.5-2.5 cubic meter/ton slurry of 50-60 ℃, the paper pulp temperature will be cooled to will be lower than 100 ℃, and making that slurry is dense reduces to approximately 10%, this can obviously not reduce the performance of second step reaction.The maximum temperature that under atmospheric pressure paper pulp is remained on permission is that people wish especially.

In another preferred embodiment of the present invention shown in Figure 3, paper pulp is sent into tower 600 from managing 60, and make it flash distillation to atmospheric pressure.The paper pulp that enters in the downflow tower will be in its possible maximum temperature, and for example 98-100 ℃, this will be increased in the consumption of peroxide in the reaction of second step.In addition, the steam of flash distillation is delivered to heat exchanger 700 by managing 90.Heat exchanger is the washings that are used for adding to before the preheating peroxide stage in the wash engine, thus, has reduced by managing 15 and 37 adding to the required quantity of steam of this section.This increased the washings of managing in 101 at it by managing 110 temperature before adding to conventional wash engine.

From beginning to the position of paper pulp from 400 dischargings of up-flow reaction tower, embodiment shown in Figure 3 is identical with Fig. 2.In this occasion, when discharging, paper pulp remains with the residue peroxide of the overwhelming majority.Paper pulp is delivered to suitable mixing valve 500 by managing 50, at this place by pipe 55 add other alkali with the PH that increases paper pulp to greater than 8.5, be preferably 9.5-10.5 to be used for second reactions steps.

After flash cooled, paper pulp delivered to conventional downflow tower 600 to carry out the reaction of second step by managing 60.The size of the downflow tower of routine fixed on can consume most remaining peroxide and can keep usually be as the criterion in paper pulp 1-5 hour.Bleached pulp drains into subsequently treatment step by managing 80 from tower 600.

Valve 500 plays reduction from the pressure of upspout 400 and make the slurries flash distillation.Just in time alkali is added in the paper pulp, and the eddy current that produces in valve plays mixed base and paper pulp in the upstream of valve.Should be understood that the effect that any mixing arrangement and valve are installed in this position of this method is basic identical.

Except that carry out the reactivation of paper pulp in mixing arrangement 550, Fig. 4 has described identical with Fig. 3, another preferred embodiment of the present invention.In this embodiment preferred, according to the present invention, it is 1-30 minute that the size of upspout is fixed on the time of staying that guarantees paper pulp, be as the criterion in preferred 5-20 minute, then, by managing 50 paper pulp delivered in the suitable mixing arrangement 550, in this device, by making remaining peroxide reactivation, subsequently, allow paper pulp carry out flash distillation by managing 55 alkali that add, and will deliver in the heat exchanger 700 by managing 90 by the steam that this flash distillation obtains, thereby will be from managing 101 water preheat to higher temperature, the water of preheating is discharged by pipe 110, and is used for washing pulp in the upstream of bleaching section.

Fig. 5 is the general flow chart that adopts bleaching schedule of the present invention.Discharge by pipe 11 from the paper pulp of wash engine or thickener 10, and deliver to blender 20, at this place, apply steam and/or bleached chemical agent by managing 12 and 13, paper pulp being heated to the desired response temperature, and the PH of paper pulp increased to the desirable value of first treatment step with peroxide.Deliver to pump 30 by managing 21 paper pulp that will heat and that regulated PH, so that paper pulp is delivered to blender 40.Because paper pulp will be heated above 100 ℃, therefore, apply steam to carry out final heating before blender by managing 34 usually.Comprise alkali, peroxide, the additional chemical agent of chelating agent and other can be added by pipe 32 and 33, and, evenly mixing with paper pulp before draining into the first peroxide reactions jar 50 by managing 41.It is 1-30 minute that the size of peroxide reactions jar 50 is fixed on the time of staying, be preferably 5-20 minute and be as the criterion so that by manage 51 deliver to device for discharging 52 before, obtaining tangible delignification and/or brightness increases.This program preferably but not necessarily optimum operation cost is, washing pulp after the first peroxide treatment step, and if wash mill be non-pressurised device, so, preferably before the first peroxide reactions jar discharging, cooling off paper pulp.Can colder dilution be added in the first peroxide reactions jar 50 by managing 53.If this wash mill requires low-consistency stock to carry out suitable operation, so, before pump, supply with filtrates to come diluted pulp be desirable by managing 54.

Paper pulp washs in wash engine 60, and washed paper pulp is delivered to blender 70 by managing 61.Second step of this preferred embodiment be can be at height dense or in dense ozone stage of operating, yet, this ozone stage preferably conventional wash engine discharging concentration 10-14% operate in dense section so that equipment funds drop into is minimum.As well known in the prior art, ozone stage must be operated being lower than under 4 the PH, to obtain optimal results.Therefore, before ozone stage, can add acid as sulfuric acid, its interpolation can be by the pipe 53 discharging positions at the first peroxide reactions jar 50, be applied on the first peroxide wash engine 60 by managing 56 with shower water, be conducted in the charging of pump 70 by managing 62 addings, or add in the independent blender (not illustrating).Then, by managing 71 the acidifying pulp pump delivered in the blender 80, and ozone added to wherein by managing 72 with pump 70.Drain into paper pulp in the ozone reaction jar 90 and be retained to many 10 minutes, so that ozone is fallen in full consumption basically.By managing 91 paper pulp delivered to device for discharging 92 from the ozone reaction jar, this device can be by a valve, and many valves, or mechanical device forms are to reduce the pressure that comes from the ozone reaction jar.By managing 93 paper pulp delivered in the gas fractionation unit 220, gas is isolated from paper pulp and is discharged by pipe 202 in this device, to handle in factory and/or reuse.By manage 102 with the degassing paper pulp deliver to pump 210.This program preferably but not necessarily optimum operation cost is, after the ozone stage before next bleaching section washing pulp.If this wash mill requires low-consistency stock to carry out suitable operation, so, before pump, supply with filtrates to come diluted pulp be desirable by managing 103.By managing 104 paper pulp delivered to wash engine 120, and use by managing 115 water that apply or filtrate and wash.

Discharge by pipe 121 from the paper pulp of wash engine 120, and deliver to blender 130, at this place, by managing 122,123 and 124 apply steam and/or bleached chemical agent, paper pulp being heated to the desired response temperature, and the PH of paper pulp increased to the desirable value of first treatment step with peroxide.Then, delivered to pump 140 with the paper pulp of regulating PH by managing 131, so that paper pulp delivered in the blender 150 by managing 141 with what heat.Because paper pulp will be heated above 100 ℃, therefore, apply steam to carry out final heating before blender by managing 144 usually.Comprise alkali, peroxide, chelating agent and other additional chemical agent can be added by pipe 142 and 143, and, evenly mixing with paper pulp before draining into the second peroxide reactions jar 160 by managing 151.Once more the size of peroxide reactions jar 160 being fixed on the time of staying is 1-30 minute, be preferably 5-20 minute and be as the criterion so that by manage 161 deliver to device for discharging 152 before, obtaining tangible delignification and/or brightness increases.Preferred washing pulp after the second peroxide treatment step; Yet if the additional other not obvious organic substance influence that is subjected to existing residue peroxide and/or dissolving of bleaching section, so, this bleaching section not necessarily.If wash mill is non-pressurised device, so, preferably before the first peroxide reactions jar discharging, cooling off paper pulp.The dilution of paper pulp can be finished in the second peroxide reactions jar 160 by managing 153 usefulness cooling fluids.If this wash mill requires low-consistency stock to carry out suitable operation, so, before pump, supply with filtrates to come diluted pulp be desirable by managing 154.Then, use by managing 156 water that apply or filtrate washing pulp in washing apparatus arranged 180.

Fig. 6 is the general flow chart that bleaching schedule of the present invention is used for existing bleacher.At present, the existing bleaching schedule commonly used of many bleachers is DcEoDED.Can improve the existing conventional bleacher, to introduce design of the present invention very economically.As shown in FIG., in transformation process, almost used all existing equipments, transform to have dropped into only three blenders, three retort, ozone generator and the various pipelines in transformation.In some occasion, must be to existing bleaching tower, the material of pipeline and miscellaneous equipment is made some change.

In example as shown in Figure 6, existing chlorination tower does not use in new bleaching schedule, but can be as auxiliary storage or other pre-processing device before new bleach plant.Existing Eo section is wherein added EDTA with being used as, DTPA, or the chelating agent section of other chelating agent, and in the PH and the temperature of control, preferably operate PH5-7 and 10-60 ℃.Usually 30-90 minute the time of staying that is present in the conventional Eo section is suitable for the chelating section.

After in existing Eo wash engine, washing, under the reactivation that is with or without according to residue peroxide of the present invention, be suitable for adding in the new blender of peroxide by slurry is transferred to, set up suitable retort, and discharging is used as first peroxide stage (P1) with existing D1 section to existing D1 tower.The PH of first peroxide stage is about 8.5-12.5, and the temperature of first step reaction is greater than 100 ℃, and preferred 105-120 ℃, the reaction time is 1-30 minute, is preferably 5-20 minute.

In existing D1 wash engine, after the washing, be suitable for adding in the new blender of ozone, set up suitable retort and gas separator, and discharging is used as ozone stage with existing E section to existing E tower by paper pulp is transferred to.This ozone stage will be preferably under the 2-4 at PH less than 4, preferably is lower than 50 ℃ at 30-70 ℃ and operates, and its reaction time is less than 10 minutes, preferably less than 5 minutes.After in existing D2 wash engine, washing, under the reactivation that is with or without according to residue peroxide of the present invention, be suitable for adding in the new blender of peroxide by slurry is transferred to, set up suitable retort, and discharging is used as second peroxide stage (P2) with existing D2 section to existing D2 tower.The PH of second peroxide stage is about 8.5-12.5, and the temperature of first step reaction is greater than 100 ℃, and preferred 105-120 ℃, the reaction time is 1-30 minute, is preferably 5-20 minute.

In existing D2 wash engine after the washing, and then paper pulp carried out post processing, but the paper pulp that preferably will fully bleach is transferred in the high dense storage tower of bleaching.

Fig. 7 has illustrated the method for optimizing of reuse filtrate in the QPZP program.Must be noted that according to the present invention after peroxide treatment, a large amount of residue peroxide is arranged at paper pulp, for example, the consumption of peroxide is as the criterion with paper pulp and is generally 2.5%, but the amount of peroxides that is consumed in reaction is usually less than 1.5% of paper pulp.Because peroxide is quite expensive bleached chemical agent, therefore, wish to reclaim this residue, to be back in the peroxide stage.As shown in the figure, this can realize by the filtrate that obtains of washing after the peroxide stage being recycled to the washing section before the peroxide stage.In order to illustrate, usually filtrate flow is shown among the figure, for example, all with 10% concentration discharging, filtrate flow and paper pulp are 9 kilograms of liquid/kilogram paper pulp for every wash engine.With dilution gfactor 2, washings are added to every wash engine, at these 11 kilograms of liquid/kilogram paper pulp normally of present bleach plant.Will be according to filtrate adverse current of the present invention recirculation by bleach plant, so that remaining peroxide is added in the paper pulp, and the remaining peroxide of the overwhelming majority brought to peroxide stage forward on wash engine.In this section, because the peroxide that carries forward with paper pulp, thereby reduced required amount of peroxide.The residue amount of peroxides that carries forward is the function of wash engine replacement ratio (detersive efficiency).For example, if the replacement ratio of wash engine is 0.85, so, with the peroxide residue that is recovered to about 60%.Identical principle is used in the recovery of the alkali that uses in the peroxide stage.Compare with the filtrate cycle scheme that other can be considered,, as shown in Figure 7,, will reduce the bleached chemical agent of using in this program widely by recycled filtrate according to the present embodiment.

Fig. 8 has illustrated another embodiment preferred of filtrate recycle in the QPZP program, if bleach plant is newly-built, does not promptly re-use existing equipment in bleach plant, and so, this method is preferred.Fig. 8 comprises the use squeezer, and the preferred two roller wash press made by Ingersoll-Rand Company that use substitute conventional vacuum or pressurization wash engine, perhaps vacuum or pressurization diffusion wash engine (diffuser).Usually filtrate flow is shown among the figure, all with 33% concentration discharging, filtrate flow and paper pulp are 2 kilograms of liquid/kilogram paper pulp for every squeezer.With dilution gfactor 2, washings are added to every wash engine, at these 4 kilograms of liquid/kilogram paper pulp normally of present bleach plant.In this occasion, identical with the design described in Fig. 7, filtrate is used to wash on squeezer.Yet, in addition, also filtrate being used for that comprises a large amount of residue peroxide can be diluted the paper pulp of discharging from squeezer, its consumption is 7 kilograms of liquid/kilogram paper pulp.The amount of peroxides that is recovered to is identical with the situation with vacuum pulp washing machine described in Fig. 7.The amount of filtrate that is recovered in squeezer is the function of squeezer replacement ratio (detersive efficiency).If the replacement ratio of squeezer is 0.40, so, will be recovered to about 60% peroxide residue altogether.Because the fund input of squeezer is similar with conventional vacuum or pressurization wash engine, therefore, for newly-built workshop, this will be attractive.Another benefit of this configuration is, if the wash mill of being installed is a squeezer, so, it can introduce high dense ozone bleaching rather than in dense ozone bleaching.This scheme has reduced bleaches required ozone amount, and has reduced the desired energy of bleach plant.

In Fig. 9, will enter the blender 100 from the paper pulp that conventional wash engine or thickener come by managing 10, at this place, add the steam that the heating paper pulp use and/or increase the alkali that paper pulp PH uses by managing 15.Heat paper pulp and PH is adjusted to about 11.Then, by managing 20, with the paper pulp that heated and regulate PH from blender 100 deliver to conventional dense pump 200, this pump is delivered to pulp pump in the blender 300 by managing 30 again.By managing 35 hydrogenperoxide steam generator is added in the blender 300, its consumption is to be enough to guaranteeing that remaining with a large amount of residue hydrogen peroxide when first step reaction finishes is as the criterion.As in the peroxide bleaching system, being conventional, also can by manage 15 with aqueous slkali add the magnesium compound of protection cellulose viscosity and sequestering agent (as silicate/or chelating agent as EDTA or DTPA}).Peroxide solutions can add by pipe 35, or adds by pipe 16 and/or 36 separately.Because according to the present invention, the temperature of paper pulp must be above 100 ℃, and at this temperature pumping paper pulp is not practicable usually, therefore, final temperature from for example 85-90 ℃ be warming up to and surpass 100 ℃ by between pump 200 and blender 300, adding steam and realize by managing 37.

Then, the paper pulp that is heated to the desired response temperature and is adjusted to desirable PH is pumped in the up-flow tubular type tower 400 by managing 40, being designed and sized to of this tower has the first step and reacts the desirable time of staying.According to the present invention, it is 5-30 minute that the size of upspout is fixed on the time of staying that guarantees paper pulp, is preferably 5-20 minute, after this time of staying, maintains a large amount of residue peroxide in slurries.By managing 50 paper pulp delivered in the suitable pressing device 560, the concentration with paper pulp in this device rises to about 25% with 10%.Filtrate is circulated to pipe 30 by managing 55, does not have used up part peroxide thereby be recovered in the first step reaction.

By managing 60 paper pulp delivered in the conventional downflow tower 600, to carry out the reaction of second step at height dense (25-30%).The size of the downflow tower of routine fixed on to consume most remaining peroxide, and paper pulp was kept 1-5 hour.By managing 80, bleached pulp is delivered to follow-up treatment step from tower 600.

For clarity sake, both be not illustrated in pump and the blender described among Fig. 1-6, and device for discharging etc., be not illustrated in the required heat exchanger of keeping optimum temperature in each bleaching section yet.According to good engineering practice, heat-exchange device can be introduced bleach plant.

Those skilled in the art will know that in order to obtain to react the desirable time of staying, the present invention can use up-flow, falls stream, up-flow/fall stream, or other configuration is implemented.In addition, those skilled in the art also will know, before reaction and afterwards, and the servicing unit that has heating and cooling paper pulp to use respectively.In addition, those skilled in the art will know, before or after the valve that (upspout) is used for keep-uping pressure in first time of staying can be arranged on mixing arrangement.The details that provides in explanation of the present invention is not to be used for limiting the scope of the invention, but for embodiment preferred clearly is described.

Those skilled in the art also will know, it is desirable or necessary using chelating agent and sequestering agent, and obtaining benefit of the present invention, and the finishing agent of the present invention of these kinds of being added not is that scope of the present invention is limited.The example of service routine has, QP, QPQP, QPQZP, QPZQP, PZQP etc.In addition, those skilled in the art also will know, in many occasions, can for example substitute chelating agent effectively less than 3 acid treatment with very low PH particularly by character; Thereby, the additional acid processing section, or substitute the chelating agent section with the acid treatment section and also will fall into scope of the present invention.

The technology of the present invention that is referred to as " PAPEROXIDE " method can be used for cellulose or ligno-cellulosic materials, and these materials have, needlebush, leaf wood, or various by chemical pulp, mechanical pulp, semi-chemical pulp, or semi-mechanical pulp, or reclaimed fibre is starched the non-wood that obtains.The benefit of these application will illustrate in the following embodiments.

The first step of PAPEROXIDE method is in high temperature (greater than 100 ℃), paper pulp and peroxide reactions to be less than 30 minutes approximately at PH8.5-12.5, preferred 5-20 minute finite time.Importantly, this first step does not produce under the metal impurities in slurries and carries out.Illustrate in the result of this first step example below:

Embodiment 1

To card uncle's valency (kappa number) is that 27.2 softwood kraft pulp sample carries out oxygen delignification (O section), to card uncle valency be 1.Then, in the time of staying of about 50 ℃ and 30 minutes, in the chelating section, this paper pulp sample is handled (Q section) in order to be as the criterion 0.6% EDTA of paper pulp.Then, sample is carried out further delignification with conventional hydrogen peroxide section (P) and ozone stage (Z), obtaining card primary valency 2.0, the paper pulp of 14.4 MPa seconds of ISO brightness 77.9% and viscosity, used condition and chemical agent consumption are listed in the table below among the A.

The condition and the chemical agent consumption section O Q P Z time of Table A-in the OQPZ section, divide 60 30 240 7 temperature, ℃ 100 50 90 23 concentration, % 10 2 10 40 pressure, psig 100---chemical agent, the about 1%O of % ₂0.6%EDTA 2.5%H ₂O ₂0.5%O ₃With bone-dry paper 2.5%NaOH H ₂SO ₄To PH6 2.5%NaOH H ₂SO ₄To the PH2 slurry MgSO that is as the criterion ₄, 0.5% MgSO ₄, 0.5%

DTPA，0.2％

According to prior art, in the pressurized peroxide section, this paper pulp is further processed, and compares with the first step of new method:

Table I: the new method of prior art and pressurized peroxide compares

Prior art (pressurization) new method (first step)

The H that is as the criterion and consumes with paper pulp ₂O ₂, % 2.2 0.9

Final PH 10.6 11.3

Time, divide 60 5

Temperature, ℃ 110 110

Brightness, %ISO 91.6 89.6

Viscosity, MPa second 8.5 8.9

At all occasions, paper pulp is all handled in 10% concentration, and uses oxygen that pressure is maintained 75psig.In bleaching process, apply following chemical agent:

Table 2: the conditions of bleaching of table 1 usefulness

The chemical agent consumption, the % consumption that is as the criterion with paper pulp

H ₂O ₂??????????????2.5

NaOH????????????????2.75

MgSO ₄??????????????0.05

DTPA????????????????0.2

This example shows, in first step of the present invention, can obtain 85% brightness improving, and, surprisingly, there is not viscosity to worsen and greatly reduce the consumption of peroxide with the very short time of staying, by contrast, prior art needed 1 hour or the longer time.Being in pressurized state although keep paper pulp with oxygen in this example, according to first step of the present invention, is not paper pulp must be exposed in the oxygen.This will illustrate in the example below:

Embodiment 2

To card uncle's valency is that 27.2 softwood kraft pulp sample carries out oxygen delignification (O section), to card uncle valency be 14.Then, under the time of staying of about 50 ℃ and 30 minutes, in the chelating section, this paper pulp sample is handled (Q section) in order to be as the criterion 0.6% EDTA of paper pulp.Then, sample is carried out further delignification, to obtain card uncle valency 1.3, the paper pulp of ISO brightness 81.8% with conventional hydrogen peroxide section (P) and ozone stage (Z).With further paper pulp being handled according to the normal pressure peroxide stage of the routine of prior art and the peroxide stage of pressurization, and as follows with first step contrast of the present invention:

Table 3: compare and use the effect of oxygen with the peroxide stage with pressurization of the routine of prior art

Prior art prior art new method

(conventional) (pressurization) (first step)

Be as the criterion with paper pulp

The H that consumes ₂O ₂, % 1.84 1.91 1.07

Final PH 11.2 11.0 11.4

Pressure, psig-75 35

Oxygen usefulness useless is useless

Vapour pressure 35

Time, divide 240 60 5

Temperature, ℃ 90 110 110

Brightness, %ISO 93.3 93.6 92.6

At all occasions, paper pulp is all handled in 10% concentration, applies following chemical agent in bleaching process:

Table 4: the conditions of bleaching of table 3 usefulness

Chemical agent	Consumption, the % consumption that is as the criterion with paper pulp
Chemical agent		????H ₂O ₂	????2.5
????NaOH	????2.75	????H ₂O ₂	????2.5
????NaOH	????2.75	????MgSO ₄	????0.05
????DTPA	????0.2	????MgSO ₄	????0.05

This example shows, according to first step of the present invention, can obtain and the very similar result of the normal pressure of the long residence time of the routine of prior art or pressurised oxygen-peroxide stage.Opposite with prior art is that in first step of the present invention, these comparable results can obtain under the situation of not using oxygen.Explanation is in short-term of the present invention in this example, and high temperature first step (5 minutes time of staying) has only used the vapour pressure of 110 ℃ of slurries.This pressure is 35psig, and by contrast, prior art need be used high pressure oxygen.By these examples with according to the present invention, can only use in short-term with the similar result of prior art, high temperature section obtains, and is in short-term described, and high temperature section will reduce widely carries out the required fund input of peroxide bleaching technology.

Basic principle of the present invention is at about 100-120 ℃, less than about 30 minutes time of staying, uses the quite short time cycle to obtain delignification and brightness improving fast in little reaction tower; Then, paper pulp is entered normal pressure promptly be lower than in about 100 ℃ conventional big retention tower and kept about 1-5 hour, washing pulp not between two sections.For 1-5 hour the time of staying of routine, the time of staying of using under normal pressure will cause further consuming hydrogen peroxide subsequently, and be accompanied by brightness and further increase.This makes slurry into to be received than the lower brightness of this routine paper pulp the time.

The design of this peroxide stage can combine with the reactivation of residue peroxide by the principle with high temperature and short residence time, succeeded by the bleaching tower reservation and the further improvement of routine.When remaining the reactivation of peroxide, hydrogenperoxide steam generator is with excessive interpolation, thereby guaranteeing has a large amount of peroxide residues after first step reaction is finished, described first step reaction was with 1-30 minute, preferred 5-20 minute the time of staying carries out, thereby, guaranteed that the peroxide residue enters the reaction of second step.Be further described in the application of awaiting the reply jointly of this Bottan of being combined in.

The present invention can be used for producing the reconstruction of existing bleach plant of ECF or TCF slurry and/or newly-built.Use in short-term being with or without preservation subsequently and being with or without under the reactivation of residue peroxide, high temperature peroxide step, and combine with the bleached chemical agent of routine, make short residence time the bleach plant very economical built.

For example, to advancing the oxygen delignification softwood kraft pulp of slurry card uncle valency about 14, uses two in short-term, the high temperature peroxide stage is intersegmentally handled with ozone gas, can produce high brightness and for example starch greater than the TCF of 80%ISO.This bleaching design makes that the required total residence time of whole bleaching operation is lower than 2 hours in bleach plant.Owing to compare with the bleaching technology of routine and to have used little Bleaching reactor, therefore, to compare with all methods that are used to produce the TCF slurry at present, this method has the low fund input that had from the end.This will illustrate in the example below:

Embodiment 3

To card uncle's valency is that 25.7 softwood kraft pulp sample carries out oxygen delignification (O section), to card uncle valency be 13.6 and viscosity be 22.4 MPas.Then, under the time of staying of about 50 ℃ and 30 minutes, in the chelating section, this paper pulp sample is handled (Q section) in order to be as the criterion 0.6% EDTA of paper pulp, then, with the P-Z-P program with association with pulp bleaching to greater than 85% ISO brightness.According to first step of the present invention, use (5-15 minute) in short-term, high temperature (107-110 ℃) condition is carried out peroxide stage, but adds conventional ozone bleaching step between two peroxide stage.

Be respectively 10,20 and 25 minutes for the total residence time in two peroxide stage, the brightness of bleached pulp is respectively 82.3,87.6 and 91.0.It must be noted that the card uncle valency of bleached pulp is very low, for example is lower than 3.Up to now, still have many pulp mills that paper pulp is carried out TCF bleaching only to use peroxide as active bleached chemical agent, the card uncle valency that floats slurry entirely that these slurry factories produce is very high, for example greater than 5, particularly consider these pulp production paper return look, the Gao Kabai valency is that people are undesirable.For the paper quality that makes by the paper pulp that uses this method to produce, first step of the present invention is used in combination with set ozone bleaching technology, have substantial advantage than present industrial implementation.

It must be noted that, during laboratory bleaching, with the oxygen pulp mixture that pressurizes, according to the digital simulation the present invention in the table 5.In the laboratory, the paper pulp temperature remains on and is higher than 100 ℃, and this is a kind of practicable simulation method for bleaching.Yet according to the data that table 2 is listed, the present invention need not to use oxygen, and this is unpredictable to require to obtain advantage of the present invention in industrial practice.

For for the purpose of laboratory simulation conveniently, the simulation of this program is included in the ozone stage of high dense operation, promptly about 40% concentration; Yet, should be understood that, for the ozone of the median dose that is as the criterion with paper pulp, promptly be less than about 0.6%, when the ozone that uses intermediate concentration, promptly during the concentration of about 10-14%, will the substantially the same result of acquisition.Therefore, the present invention is not limited to use high dense ozone, in fact, dense ozone in preferred the use, so that utilize the existing equipment of slurry factory, and this will obtain describing in preferred embodiments.

Those skilled in the art will know, application principle of the present invention, and promptly also available other chemical agent preferably operated in acid medium (being that PH is lower than about 7) existing or in the future of two peroxide stage and intersegmental acid treatment section is used.The example of other intersegmental processing includes, but are not limited to peracetic acid, and permonosulphuric acid (Caro ' s aeid), the mixture of various enzyme finishing agents and these finishing agents.

In addition, it must be noted that, for special paper pulp, owing to be with or without under the situation of intersegmental processing and the conventional peroxide stage of prior art can be being combined with a peroxide bleaching section of the first step according to the present invention, so need not that first step carries out the operation of two peroxide stage according to the present invention.What can expect is, uses more than two peroxide stage and to have intersegmental processing will be effective to the present invention.Although consider from the angle of economy, should limit hop count, realizing minimum fund input, not to be used for limiting scope of the present invention by the given example of one or two peroxide stage just.

The P-Z-P bleaching schedule P1 section of table 5. assessment employing new method (pres ' d H ₂O ₂) the new method conventional method is as the criterion H with paper pulp ₂O ₂% 2.5 2.5 2.5 2.5 2.5H ₂O ₂% absorbs 0.5 1.1 1.1 1.3 2.1 and is as the criterion with paper pulp, NaOH% 2.5 2.5 2.5 2.5 2.5 is as the criterion with paper pulp, and DTPA% 0.2 0.2 0.2 0.2 0.2 is as the criterion MgSO with paper pulp ₄0.05 0.05 0.05 0.05 0.05 total time of %, divide 5 15 15 20 60 temperature, ℃ 107 110 110 110 110 oxygen are pressed, psig-75 75 75 75 75 concentration, 8.8 7.5 6.7 6.1 4.9 brightness of % 10 10 10 10 10 final PH 11.4 11.7 11.6 11.3 10.5 card uncle valencys, %ISO 60.3 65.5 69.0 70.4 77.9Z sections (ozone) are as the criterion O with paper pulp ₃% 0.5 0.5 0.5 0.5 0.5O ₃% absorbs 0.49 and does not measure total time, divide 77777 temperature, ℃ 23 23 23 23 23 concentration, % 40 40 40 40 40 final PH 2.4 2.4 2.0 2.0 2.3 card uncle valencys 3.7 2.0 1.1 1.1 are not measured brightness, and %ISO 70.6 76.5 80.8 79.8 85.7P2 sections (pres ' d H ₂O ₂) the new method conventional method is as the criterion H with paper pulp ₂O ₂% 2.5 2.5 2.5 2.5 2.5H ₂O ₂% absorbs 0.9 0.8 0.9 0.9 2 and is as the criterion with paper pulp, NaOH% 2.5 2.5 2.5 2.5 2.5 is as the criterion with paper pulp, and DTPA% 0.2 0.2 0.2 0.2 0.2 is as the criterion MgSO with paper pulp ₄0.25 0.25 0.25 0.25 0.25 total time of %, divide 55 10 5 60

Temperature, ℃ 108 110 110 109 110

Oxygen is pressed, and psig 75 75 75 75 75

Concentration, % 10 10 10 10 10

Final PH 11.3 11.1 11.4 11.6 10.6

Card uncle valency 2.0 is not measured 0.4 and is not measured

Brightness, %ISO 82.3 87.6 91.0 31.2 93.6

As a further example, use for example existing extracting, hypochlorite or ClO 2 bleaching tower are as in peroxide bleaching section of the present invention in short-term, retention tower after the high-temperature step, compare with previous example, reduced the running cost of bleaching schedule, and only need add least equipment existing bleach plant.

Embodiment 4

To card uncle's valency is that 25.7 softwood kraft pulp sample carries out oxygen delignification (O section), to card uncle valency be 13.6.Then, under the time of staying of about 50 ℃ and 30 minutes, in the chelating section, this paper pulp sample is handled (Q section) in order to be as the criterion 0.6% EDTA of paper pulp, then, with the P1-Z-P2 program with association with pulp bleaching to greater than 85% ISO brightness.According to the present invention, use (5-15 minute) in short-term, high temperature (107-110 ℃) condition is carried out peroxide stage, but in short-term at each, after the high temperature peroxide stage, additional normal pressure retention time, and between two peroxide stage in conjunction with conventional ozone bleaching step.

As can be seen from Table 6, according to the present invention, when identical peroxide dosage (paper pulp relatively), in short-term of the present invention, behind the high temperature first step the obtained result of additional normal pressure diffusion with use 1-3 hour obtained result of pressurization diffusion suitable according to prior art at every section.Owing to can reuse existing bleaching tower as follow-up reservation in many pulp mills, make required capital input minimum, therefore, this especially wishes.As previously mentioned, investment for 1-3 hour pressurization diffusion is quite high, and, also foreseeablely be 1-5 hour new normal pressure diffusion jar even need to build the time of staying, so, for new bleaching schedule, this new normal pressure diffusion jar adds in short-term (5-15 minute) High temperature diffusion jar, when comparing with the required fund of prior art, still has suitable attraction economically.According to the present invention, (5-20 minute) upspout is used in combination with the existing bleaching tower of bleacher (1-4 hour) by in short-term, and the investment of each peroxide bleaching section is Jiang Zhi $250, and 000 or lower, perhaps, the gross investment Yue Wei $90 1,000,000 of North America industry 350 tame pulp mills.Compared with prior art, the present invention can save Zi Jin $130-430 1,000,000.

It is in short-term that the first step by each P section is adopted in table 6. assessment, and the high temperature and second step are long residence times, the PZP bleaching schedule of the present invention that low temperature is formed.

One-step method two step method one-step method

P1 section (15 minutes) (15+240 minute) (60 minutes)

Be as the criterion H with paper pulp ₂O ₂% 2.5 2.5 2.5

H ₂O ₂, % absorbs 1.1 2.1 1.1

Be as the criterion with paper pulp, NaOH% 2.5 2.5 2.5

Be as the criterion MgSO with paper pulp ₄% 0.05 0.05 0.05

Be as the criterion with paper pulp, DTPA% 0.2 0.2 0.2

Concentration, % 10 10 10

Total time, minutes 15 225 60

The first step 15 15 60

Second step--240--

Temperature, ℃

The first step 110 110 110

Second step--90--

Oxygen is pressed, psig-75 75 75

(the only first step)

Final PH 11.6 11.1 10.5

Card uncle valency 6.7 5.2 4.9

Viscosity, MPa second 18.2 76.6 77.9

ISO brightness, % 69.0 76.6 77.9

The Z section

Be as the criterion O with paper pulp ₃% 0.5 0.5 0.5

Concentration, % 40 40 40

Total time, divide 777

Temperature, ℃ 23 23 23

Final PH 2.0 2.0 2.0

Card uncle valency 1.1 is not measured--

Viscosity, MPa second 12.3 11.0 14.7

Brightness, %ISO 80.8 84.6 85.7

The P2 section

Be as the criterion H with paper pulp ₂O ₂% 2.5 2.5 2.5

H ₂O ₂, % absorbs 0.9 2.3 2.0

Be as the criterion with paper pulp, NaOH% 2.5 2.5 2.5

Be as the criterion MgSO with paper pulp ₄% 0.25 0.25 0.25

Be as the criterion with paper pulp, DTPA% 0.2 0.2 0.2

Concentration, % 10 10 10

Total time, minutes 10 250 60

The first step 10 10 60

Second step--240--

Temperature, ℃

The first step 110 110 110

Second step--90--

Oxygen is pressed, psig-75 75 75

(the only first step)

Final PH 11.4 11.4 10.6

Card uncle valency can not get

Viscosity, MPa second 10.9 9.5 8.7

Brightness, %ISO 91.0 93.4 93.6

Given data are that the performance of a little preferred embodiment is carried out quantitative analysis, but this is not that scope of the present invention is limited.Those skilled in the art will know that for obtaining benefit of the present invention, the present invention can implement in many ways.Provide some examples and be used for illustrating this point, but this and do not mean that and limit the scope of the invention.It is some occasion of " PAPEROXIDE " method that following table has been described the present invention that can adopt at existing or newly-built bleach plant:

1. be used for the delignification before bleach plant.

2. be used for final brightening at last at bleach plant.

3. substitute existing section of bleach plant.

4. existing section is improved, to improve performance or to reduce the chlorine compound that uses in the bleach plant.

5. before further bleaching section, be used as preliminary treatment.

6. in above-mentioned any situation, use more than a kind of section new or modification

7. more than one new section in conjunction with one or more intersegmental processing.

Claims

1, a kind of method with hydrogen peroxide bleaching wood pulp and other cellulose and lignocellulosic fibre material (paper pulp), this method comprises:

With the concentration adjustment of described paper pulp to 8-18%;

Add alkali so that the PH of described paper pulp greater than 8.5;

Add hydrogen peroxide, its consumption is at least 0.5% in described paper pulp oven dry weight;

The temperature of described paper pulp is heated to greater than 100 ℃, meanwhile keeps enough pressure to prevent the slurries boiling;

By a reaction tower, its through-rate is less than 45 minutes with the reaction time in described reaction tower and is as the criterion with described paper pulp;

The temperature of described paper pulp is cooled to is lower than 100 ℃;

Under normal pressure, in reaction tower, deposit described paper pulp and allow reaction carry out 1-5 hour till the remaining hydrogen peroxide of the overwhelming majority all runs out of; With

Draw off described paper pulp in order to further handling.

2, the process of claim 1 wherein, add enough alkali, so that the PH of described paper pulp is greater than 9.5.

3, the process of claim 1 wherein, add enough alkali, so that the PH of described paper pulp is at 9.5-11.5.

The process of claim 1 wherein that 4, make described paper pulp by described reaction tower, its through-rate was as the criterion between 5 and 20 minutes with the reaction time in described reaction tower.

5, a kind of method with hydrogen peroxide bleaching cellulose and lignocellulosic fibre material (paper pulp), this method comprises:

With the concentration adjustment of described paper pulp to 10-18%;

Add alkali so that the PH of described paper pulp greater than 8.5;

Add hydrogen peroxide, so that after by first reaction tower, can provide remaining peroxide;

Add alkali so that the PH of described paper pulp greater than 9.0;

Draw off described paper pulp in order to further handling.

6, the method for claim 5 wherein, is added enough hydrogen peroxide, and its consumption is a 0.5-5.0% weight.

7, the method for claim 5 wherein, makes the PH of paper pulp make described residue hydrogen peroxide reactivation greater than 9.5 by adding enough alkali.

8, a kind of method with hydrogen peroxide bleaching cellulose and lignocellulosic fibre material (paper pulp), this method comprises:

With the concentration adjustment of described paper pulp to 8-18%;

Add alkali so that the PH of described paper pulp greater than 8.5;

Add hydrogen peroxide, its consumption is counted 0.5-5.0% with described paper pulp oven dry weight;

The temperature of described paper pulp is cooled to is lower than 100 ℃;

Draw off described paper pulp in order to further handling.

9, a kind of tri-stage bleaching program that is used for cellulose and ligno-cellulosic materials (paper pulp) comprises the steps:

Described paper pulp is handled through first section hydrogen peroxide bleaching section, and described first section comprises the steps:

With the concentration adjustment of described paper pulp to 8-18% and add alkali and hydrogen peroxide so that the PH of described paper pulp greater than 8.5, the consumption of hydrogen peroxide is counted 0.5-5.0% with described paper pulp oven dry weight;

The temperature of described paper pulp is heated to greater than 100 ℃, meanwhile keeps enough pressure to prevent the slurries boiling, add and depress, by a reaction tower, its through-rate is less than 45 minutes with the reaction time in described reaction tower and is as the criterion with described paper pulp;

Cool off described paper pulp and the paper pulp of cooling is delivered to wash engine, in wash engine, from paper pulp, remove the material of most unreacted bleached chemical agent and dissolving, and, if necessary, pulp density is adjusted to the preferred value that is used for second section bleaching processing;

Described paper pulp is handled through the described second bleaching section, and described bleaching section comprises the steps:

Add enough acid or alkali and be adjusted to the preferred value of bleaching agent with the PH with paper pulp, and described paper pulp is introduced in the blender, in this blender, the second bleached chemical agent mixes with described paper pulp;

Paper pulp is delivered to the retort from blender, and in this retort, the time of staying of described paper pulp is as the criterion so that the most chemical agents that added are consumed;

Described paper pulp is delivered to the wash engine from described retort, in wash engine, from paper pulp, removed the material of most unreacted bleached chemical agent and dissolving, and, if necessary, pulp density is adjusted to 8-18%; With

After regulating pulp density, paper pulp is handled through tri-stage bleaching, to handle described step identical with described first section hydrogen peroxide bleaching in steps in the institute of described the 3rd section processing.

10, the method for claim 9 wherein, in the second bleaching section, is added enough acid and is adjusted to the PH with paper pulp and is lower than 4, and described paper pulp is introduced in the blender, in blender, will mix with described paper pulp at the ozone in the suitable carrier gas; Paper pulp is delivered to the ozone reaction jar from blender, in this jar, the time of staying of described paper pulp is up to 10 minutes more than, so that can consume all ozone, and paper pulp delivered to the wash engine from described ozone reaction jar, in wash engine, from paper pulp, remove the material of most unreacted bleached chemical agent and dissolving, and, if necessary, pulp density is adjusted to 8-18%, uses for the 3rd section processing.

11, the method for claim 10, wherein, the ozone amount that applies in absolute dried paper pulp weight between 0.1-2.0%.

12, the method for claim 10 wherein, is carried out the ozone bleaching section in the concentration of 8-18%.

13, the method for claim 12, wherein, the ozone amount that applies in absolute dried paper pulp weight between 0.2-1.0%.

14, the method for claim 9 wherein, comprises the ozone treatment more than a section, paper pulp is not washed between each section.

15, the method for claim 9 wherein, is carried out other blanching step between first peroxide treatment and second peroxide treatment.

16, the method for claim 9, wherein, the concentration adjustment that will advance slurry is extremely greater than 20%; To greater than 20% concentration, and the filtrate that will bleach section back dehydration obtains is used for diluting and advances to starch, and therefore, reclaimed most residue hydrogen peroxide with the dewatering of pulp that draws off.

17, the method for claim 16 wherein, will be deposited on the reaction tower and allow react and carry out 30 minutes-3 hours, till overwhelming majority residue peroxide consumption is fallen from the paper pulp of this section discharge.

18, the method for claim 17 wherein, before paper pulp is deposited in the described reaction tower, is added alkali so that remaining hydrogen peroxide reactivation.

19, the method for claim 17 wherein, before paper pulp is deposited in the described reaction tower, is cooled off paper pulp.