CN101871176A

CN101871176A - The green liquor pretreatment of ligno-cellulosic materials

Info

Publication number: CN101871176A
Application number: CN201010154229A
Authority: CN
Inventors: 纳姆西·星
Original assignee: Andritz Inc
Current assignee: Andritz Inc
Priority date: 2009-04-21
Filing date: 2010-04-20
Publication date: 2010-10-27
Also published as: JP2010255171A; SE535028C2; SE1050387A1; CA2698163A1; US20100263813A1; BRPI1001050A2; RU2010115741A; CL2010000390A1

Abstract

The present invention relates to the green liquor pretreatment of ligno-cellulosic materials, this technology may further comprise the steps: (a) with the very first time section of ligno-cellulosic materials decatize between 1 to 60 minute; (b) after decatize, the ligno-cellulosic materials that uses green liquor that described decatize is crossed in impregnating autoclave under the temperature between 110 ℃ to 150 ℃ floods second time period smaller or equal to 5 minutes; (c) after dipping, the described ligno-cellulosic materials of continuously cooking prepares chemical grade paper pulp in boiling vessel.

Description

The green liquor pretreatment of ligno-cellulosic materials

The application requires the U.S. Patent application No.61/171 that submitted on April 21st, 2009,109 benefit of priority, and its content is incorporated herein in full with it.

Technical field

The present invention relates in general to the ligno-cellulosic materials that floods ligno-cellulosic materials and boiling dipping in continuous sulfate pulping technology.

Background technology

Proposed at ligno-cellulosic materials, for example comprised and use black liquor, green liquor and/or white liquid scheme in the cork sheet and hardwood sheet processing procedure as maceration extract.Referring to for example U.S. Patent No. 5,674,359; U.S. Patent No. 3,520,773; U.S. Patent No. 1,691,511; EP 0810321B1; People such as Svedman, use green liquor and derivative thereof to improve sulfate pulping technology, " paper industry technological associations magazine ", the 81st volume, the 10th phase, 151-158 page or leaf (in October, 1998) (Svedman et al., The Useof Green Liquor And Its Derivatives in Improving Kraft Pulping, TappiJournal Vol.81, No.10, pp.151-158 (Oct.1998)); People such as Ban, improvement to the low-cost high repayment of sulfate pulping operation, " paper industry technological associations 2001 slurrying meeting periodicals " (Ban et al., Low Capital, High Return Modifications to Kraft PulpingOperations, Tappi 2001 Pulping Conference); People such as Ban, the selection correlation of preliminary treatment slurrying parameter: the optimization of the green liquor pretreatment condition of improved sulfate pulping technology, Paperia jaPuu-" papermaking and timber magazine ", the 86th volume, the 2nd phase, 102-108 page or leaf (2004) (Ban et al., The Relationship of Pretreatment Pulping Parameters With Respect toSelectivity:Optimization of Green Liquor Pretreatment Conditions forImproved Kraft Pulping, Paperia ja Puu-Paper and Timber, Vol.86, No.2, pp.102-108 (2004)); People such as Ban, basic correlation between green liquor (GL) preliminary treatment and the pulp quality, " 2002 paper industry technological associations autumn session and trade fair " (Ban et al., Fundamental Correlations Between Green Liquor (GL) Pretreatment andPulp Qualities, 2002 Tappi Fall Conference﹠amp; Trade Fair); People such as Ban, the sulfate green liquor preliminary treatment of cork sheet (Ban et al., Kraft Green Li quor Pretreatmentof Softwood Chips).The chemical affect of paper pulp carbohydrate (II), " paper pulp and paper science magazine ", the 29th volume, the 4th phase, 114-119 page or leaf (in April, 2003) (Part II:Chemical Effectof Pulp Carbohydrates, Journal of Pulp and Paper Science, Vol.29, No.4, pp.114-119 (April 2003)); People such as Mao, technology evaluation to the hardwood biorefinery that uses nearly neutral hemicellulose preextraction technology, " 2007 american chemical IEEEs annual meeting meeting periodical " (Mao, et al., Technical Evaluation of a Hardwood Biorefinery Using the " Near-Neutral " Hemicellulose Pre-Extraction Process, 2007 AIChE AnnualMeeting); People such as Lucia, the green liquor preliminary treatment of wood chip can improve slurrying efficient, " papermaking epoch ", in November, 2002/December, 24-26 (Lucia et al., Green Liquor Pretreatment of ChipsCould Boost Kraft Pulping Efficiency, PaperAge, Now/Dec 2002, pp.24-26).

Black liquor impregnation technology is for example in U.S. Patent No. 5,192,396 and U.S. Patent No. 5,346,591 in describe to some extent.In addition, be present in the importance of the high curing degree in the black liquor and the use in impregnation technology thereof, describe to some extent in 686 in U.S. Patent No. 5,660.

Though known black liquor can be used, its use may relate to some difficult problems.One of difficult problem may be the change that the pH value occurs, causes separating out of the lignin do not expected.Another difficult problem is that the material that just exists in black liquor may be unfavorable to pulp quality and chemical consumption.The ratio of known vulcanized sodium and NaOH may be very important to the liquid that obtains high curing degree.

The scheme that has proposed also comprises the use of green liquor as steeping medium.But these schemes relate to batch process and maybe need long dip time (for example above 30 minutes), and this needs big and/or a plurality of containers come to keep constant productivity ratio at the commercial continuous processing that is being used for manufacturing chemistry level paper pulp.These existing methods have shortcoming, and are for example relevant with maintenance cost with the increase fund cost.

Have been found that the green liquor short time is favourable as maceration extract.The advantage of green liquor is to contain the favourable sulphur compound that is present in the black liquor, and does not contain other solid chemical compounds do not expected in the black liquor.And the ratio of vulcanized sodium and NaOH may be higher.

Summary of the invention

On the one hand, the present invention relates in general to the continuous processing that is used to prepare chemical grade paper pulp, and described technology may further comprise the steps: (a) with the very first time section of ligno-cellulosic materials decatize in 1 to 60 minute; (b) after the decatize, the ligno-cellulosic materials that uses green liquor that described decatize is crossed in impregnating autoclave under the temperature between 110 ℃ to 150 ℃ floods second time period smaller or equal to 5 minutes; (c) after the dipping, the described ligno-cellulosic materials of continuously cooking prepares chemical grade paper pulp in boiling vessel.

Description of drawings

Fig. 1 is the schematic diagram with two jars of decoction systems of dipping function.

The specific embodiment

Used term " black liquor ", " white liquid " and " green liquor " and its its common sense aggregatio mentium in slurrying and pulp technology for making paper.For example, black liquor can be often referred to the liquid that extracts or the residual liquid after the boiling in digestion process; White liquid can be often referred to the mixture of NaOH and sodium bisulfide; Green liquor can be often referred to the inorganic fused mass from the dissolving of recovery boiler.Green liquor can comprise for example vulcanized sodium, sodium carbonate and NaOH.

The ligno-cellulosic materials that uses in this technology is generally wood chip, and this wood chip is cork or hardwood species or its mixture.Also may use other cellulosic materials, for example straw, sisal leftover bits and pieces (begasse) etc.

The schematically illustrated continuous processing that relates to two can system of Fig. 1, green liquor is immersed in the green liquor jar and carries out, and boiling is carried out in boiling vessel.As example, this system can comprise high pressure feeder 10 or other pressue devices, the pump of the ligno-cellulosic materials slurry pressure that for example is used to raise, and it gives impregnating autoclave 11 chargings; Lead to the high pressure entry pipeline 12 at impregnating autoclave 11 tops 13; With behind the sieves at impregnating autoclave 11 tops through arriving the Returning pipe 17 of other positions in high pressure feeder 10 or the feed system.

The ligno-cellulosic materials of presteaming (for example ligno-cellulosic materials of decatize under atmospheric pressure) can be fed to high pressure feeder 10 or other pressue devices.Alternately, ligno-cellulosic materials can enter impregnating autoclave 11 (or even in 11 primary stages of impregnating autoclave) decatize under high pressure before after high pressure feeder 10 or other pressue devices shift.Decatize can carried out under the pressure arbitrarily, and may carry out under overheated condition.

Green liquor, white liquid and/or black liquor can add pipeline 17 to, flooding, and add each recirculation conduit and the system that links to each other with boiling vessel 30 to, and boiling vessel 30 can be any boiling vessel that is applicable to use liquid boiling ligno-cellulosic materials.Slurry (ligno-cellulosic materials and liquid) is fed to the top of boiling vessel 30 by pipeline 29, and from the sieves back at boiling vessel 10 tops liquid is moved in the pipeline 31, by heater 32 heating.

Boiling vessel 30 can be the boiling vessel of any tradition or non-traditional type, no matter be hydraulic pressure or vapour phase.And impregnating autoclave 11 can also comprise one or more Dilvar zones, and for example two same districts not at first are low-temperature spaces, be the high-temperature region then, and may have effective alkali in various degree in each district.And, the green liquor of each related in variable concentrations of two or more Dilvar zones, white liquid and/or black liquor.

In dipping process, alkali is diffused in the fibre wall.This opens timber structure, and may be partly dissolved a part of wooden in preprocessing process.Sustainable short time of this dipping process (for example 1 minute), or long-time (for example reaching several hours).Dipping temperature is about 110 ℃-150 ℃, more preferably at about 120 ℃.

In impregnating autoclave 11, one or more Dilvar zones can be cocurrent flow and/or adverse current (with any combination or arrangement).Though illustrate, it should be understood that in some cases immersion system can be positioned on the top of boiling vessel 30 with independent impregnating autoclave.Boiling vessel 30 also can be any adequate types that is used for slurrying and paper mill.

Be to use green liquor to prepare the continuous processing of paper pulp among the embodiment.Compare with existing technology, this technology may need chemicals still less.This technology may generally include these steps: (a) decatize ligno-cellulosic materials; (b) after the decatize, use green liquor in impregnating autoclave, to flood the ligno-cellulosic materials that decatize is crossed; (c) after the dipping, continuously cooking ligno-cellulosic materials under normal condition may add white liquid, with preparation chemical grade paper pulp.

In certain embodiments, before the continuously cooking ligno-cellulosic materials, may have two or more other impregnation steps that relate to green liquor, white liquid and/or black liquor.Preferably, green liquor is discharged, and and then the ligno-cellulosic materials of dipping is delivered to boiling vessel, uses liquid (for example white liquid) to carry out boiling and need not other one or more impregnation steps.

In step (a), with ligno-cellulosic materials, for example 1-60 minute time (preferred about 15 minutes) of cork sheet or hardwood sheet decatize (for example under 100 ℃ and 1 bar pressure), do not add any chemicals (for example under the situation that does not have white liquid, black liquor or green liquor) in the water vapour.Other temperature and pressures (for example 6 crust or 10 crust) also may be applicable to steaming step.

In step (b), be immersed in the time (for example 1 minute, 2 minutes or 5 minutes) of carrying out under the high pressure (for example 6 crust or 10 crust) smaller or equal to 5 minutes.Dipping can preferably carry out under about 120 ℃ under about 110 ℃-150 ℃ temperature.After required contact time, unnecessary green liquor can be removed before in step (c).

Use above-mentioned technology, the applicant believes that the good transfer of sulphidity from the green liquor to the ligno-cellulosic materials can be in the early stage realization of handling, and this can show himself have whole digesting technoloy highly beneficial.Compare with the technology that sulphidity shifts during the late stages of developmet, the known sulphidity technology of phase transition in early days helps to improve prepared pulp property.Referring to the U.S. Patent No. 5,660,686 of for example authorizing people such as Henricson.

From the test (with the comparative examples of under 90-100 ℃, carrying out) of using above-mentioned technology, can find under about 120 ℃ dipping temperature, and contact time between 2 to 5 minutes, Kappa number can be subjected to the positive impact of two Ka Bai units.It is believed that pressure is not key factor, but this means when using green liquor under the uniform temp different pressures, to flood, not owing to pressure change is benefited.

Under dipping temperature, study the influence of contact time simultaneously.Make green liquor contact specific three time periods of ligno-cellulosic materials: 1 minute, 2 minutes and 5 minutes.Though it is different that 1 minute situation Kappa number during with 2 minutes is carried out in contrast contact, contact that Kappa number does not have significant difference when carrying out 5 minutes and 2 minutes contrasting.These tests contact time can show the wall of green liquor rapid osmotic ligno-cellulosic materials, to fill the interstitial space in the ligno-cellulosic materials wall.

This short contacting time may be very important, has stable p H condition because it can make in the dipping process.Short green liquor makes green liquor can remove and use before the white fluid exchange, the minimum change of the pH of ligno-cellulosic materials and green liquor mixture contact time.Metastable pH environment can reduce the possibility that lignin is separated out from the solvable lignin of acidity.Reduce lignin and separate out the side reaction that can cause still less, for example lignin cohesion.

The benefit of short time green liquor dipping as indicated above can also comprise the consumption of minimizing (for example reaching 40%) digesting technoloy effective alkali (EA) addition.For example, in the technology of not using green liquor, obtain card uncle several 16 and may need 18% (EA).Use described green liquor impregnation technology, card uncle several 16 may need 10%EA to change.This remarkable reduction of EA amount can reduce the size of causticizing plant, and reduces the size of limekiln equipment.The reducing of these equipment (and impregnating autoclave size obviously reduce) can reduce gross energy loss in the factory, and reduces pollutant, for example carbon dioxide.

Though the present invention is described with preferred embodiment in conjunction with being considered to most realistic at present, but should understand, the invention is not restricted to described embodiment, but opposite, be intended to cover the form of distortion separately and the equivalent arrangements that are included in the claims spirit and scope.

Claims

1. continuous processing that is used to prepare chemical grade paper pulp, described technology may further comprise the steps:

(a) with the very first time section of ligno-cellulosic materials decatize between 1 to 60 minute;

(b) after decatize, the ligno-cellulosic materials dipping that uses green liquor that described decatize is crossed under the temperature between 110 ℃ to 150 ℃ in impregnating autoclave is less than or equal to 5 minutes second time period; With

(c) after dipping, the described ligno-cellulosic materials of continuously cooking prepares chemical grade paper pulp in boiling vessel.

2. continuous processing according to claim 1 is characterized in that described ligno-cellulosic materials comprises wood chip.

3. continuous processing according to claim 1 is characterized in that, step (a) is carried out having steam and do not exist under the situation of white liquid, green liquor and black liquor.

4. continuous processing according to claim 1 is characterized in that, described very first time section continues about 15 minutes.

5. continuous processing according to claim 1 is characterized in that, step (a) is carried out under atmospheric pressure.

6. continuous processing according to claim 1 is characterized in that, step (a) is carried out under the pressure smaller or equal to 10 crust.

7. continuous processing according to claim 1 is characterized in that, the time period that step (b) is carried out is less than or equal to 2 minutes.

8. continuous processing according to claim 1 is characterized in that, the time period that step (b) is carried out is less than or equal to 1 minute.

9. continuous processing according to claim 1 is characterized in that, step (b) is carried out under the pressure that is less than or equal to 10 crust.

10. continuous processing according to claim 1 is characterized in that, step (b) is carried out under the pressure that is less than or equal to 6 crust.

11. continuous processing according to claim 1 is characterized in that, described continuous processing also is included in the step of removing unnecessary green liquor between step (b) and the step (c).