EP0012960B1 - Verfahren und Vorrichtung zum kontinuierlichen Aufschliessen von Pflanzenfasermaterial - Google Patents

Verfahren und Vorrichtung zum kontinuierlichen Aufschliessen von Pflanzenfasermaterial Download PDF

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Publication number
EP0012960B1
EP0012960B1 EP79105195A EP79105195A EP0012960B1 EP 0012960 B1 EP0012960 B1 EP 0012960B1 EP 79105195 A EP79105195 A EP 79105195A EP 79105195 A EP79105195 A EP 79105195A EP 0012960 B1 EP0012960 B1 EP 0012960B1
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EP
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Prior art keywords
reactor
fibre material
plant fibre
organic solvent
centre
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Application number
EP79105195A
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German (de)
English (en)
French (fr)
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EP0012960A1 (de
Inventor
Manfred Dr. Baumeister
Eugen Edel
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Md-Organocell Gesellschaft fur Zellstoff- und Umw
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MD Papier GmbH and Co KG
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Application filed by MD Papier GmbH and Co KG filed Critical MD Papier GmbH and Co KG
Priority to AT79105195T priority Critical patent/ATE1914T1/de
Publication of EP0012960A1 publication Critical patent/EP0012960A1/de
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Publication of EP0012960B1 publication Critical patent/EP0012960B1/de
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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
    • D21C3/00—Pulping cellulose-containing materials
    • D21C3/20—Pulping cellulose-containing materials with organic solvents or in solvent environment

Definitions

  • the invention relates to a method and a device for the continuous digestion of plant fiber material with organic solvent.
  • DE-A-2637449 describes a solvent extraction process for the production of cellulose pulp, in which lignin is extracted from finely divided fibrous plant material at elevated temperature and pressure with an aqueous solution of a lower aliphatic alcohol.
  • This method works with a plurality of extractors working in batches, with a series of work stages following one another in each extractor.
  • This known method is not suitable for the continuous, economical production of cellulose from plant fiber material.
  • the investment costs are disproportionately high due to the large number of extractors required.
  • the heating-up time per batch is very long, unless disproportionately large amounts of solvent are used, so that hydrolytic degradation reactions of the cellulose and hemicellulose take place before the high temperature required for the dissolution of the lignin is reached. Therefore, it is not possible with the known method to obtain pulp for paper production with sufficient strength.
  • US-A-3 585 104 and DE-B-2 644 155 describe continuous digestion and recovery processes for vegetable fiber raw materials for the production of cellulose using organic solvents. No pre-impregnation is used in these processes. For this reason, the material flow is easily blocked, especially since a forced transport through the reactor is not provided.
  • the digested material is washed with cold organic solvent after boiling. However, lignin residues are not removed by washing with cold solvent.
  • the organic solvent is then pressed out of the digested material in a screw press.
  • the digested material is then washed in a separate device with an aqueous sodium hydroxide solution. This solution is finally pressed in a second screw press. This procedure is not very effective and very expensive. In particular, the need to drive the organic solvent out of the digested cold material leads to an increased expenditure of energy.
  • the invention has for its object to provide a method and an apparatus for the continuous digestion of plant fiber material with organic solvent, wherein the essential components of the plant fiber material, namely lignin, hemicellulose and cellulose, can be obtained separately and in pure form, on an industrial scale works economically, which is characterized by a simple procedure, in particular the disadvantages of the known methods described above are avoided, and which provides a high quality and easily bleachable pulp.
  • the invention relates to a process for the continuous digestion of plant fiber material, in which the plant fiber material is treated in countercurrent with organic solvent and the plant fiber material is introduced at the head of a reactor by means of an introduction device and is guided downwards through this and cellulose is applied to the reactor base, organic solvent in countercurrent to the plant fiber material and is withdrawn at the top of the reactor, and the loaded extraction liquid is separated into the essential constituents lignin, hemicellulose and solvent, which is characterized in that the plant fiber material is impregnated in an impregnation device with organic solvent that impregnated Vegetable fiber material is forced down through the reactor, in the middle of the reactor organic solvent with a temperature between 130 and 210 ° C as the extraction liquid eight, and fed in as washing liquid at the bottom of the reactor, led upward in countercurrent to the plant fiber material and drawn off in the middle of the reactor.
  • the invention further relates to a device for the continuous digestion of plant fiber material with organic solvent, in which a pretreatment device for the plant fiber material is connected directly to the head of the reactor via a pressure lock and an outlet for the digested plant fiber material on the reactor base, and a vent for the reactor head the loaded extraction liquid and separation devices are provided for the separation of lignin, hemicellulose and solvent, which is characterized in that the pretreatment device is an impregnator designed as a screw conveyor, integrally in the reactor Cooking zone and a washing zone are provided, the reactor at the bottom comprises one or more inlets for the washing liquid in the central region, a discharge for the washing liquid and one or more feeds for the extraction liquid and in the reactor head an introduction device for the plant fiber material.
  • a pretreatment device for the plant fiber material is connected directly to the head of the reactor via a pressure lock and an outlet for the digested plant fiber material on the reactor base, and a vent for the reactor head the loaded extraction liquid and separation devices are provided for the separation of lignin
  • the advantages of the method according to the invention are, in particular, that economic operating sizes can be achieved with only 50 to 100 tonnes per day, that the raw materials contained in the raw material, namely hemicellulose and lignin, are largely obtained in native form, and that the organic ones used for the extraction are obtained Solvents can be recovered and reused, for example, by simple distillation and subsequent condensation.
  • the process can be used for all pumpable, pourable and free-flowing cellulose-containing raw materials.
  • wood from indigenous and tropical provenance as well as annual plants such as straw and bagasse are considered as raw materials.
  • the cellulose obtained by the process according to the invention is excellently suitable for paper production due to its high quality.
  • the method according to the invention now allows for the first time to obtain the other essential constituents, namely lignin and hemicelluloses, in the form of pure, valuable raw materials.
  • the hemicelluloses are suitable for a wide variety of uses, the use of which is particularly noteworthy in the following areas: production of sugars, in particular sorbitol and mannitol; Manufacture of thickeners, adhesives, sizing and thickening agents for the paper, textile and coating industries; Further processing to alcohol by fermentation. It should be emphasized that it can be advantageous to reuse the alcohol obtained from the hemicelluloses as a solvent in the process according to the invention.
  • lignin can be obtained in native and largely pure form.
  • Lignin is an extremely valuable raw material. It is obtained as a polyol in the process and is particularly suitable for the production of synthetic resins. A reaction with aldehydes is particularly suitable.
  • synthetic resins that can be obtained from lignin particular emphasis should be given to polyurethanes, acetal resins, epoxy resins and phenolic resins.
  • Organic solvents are used as the extraction liquid.
  • the organic solvents should preferably be miscible with water in any ratio.
  • Particularly suitable are aliphatic alcohols with 1 to 6 carbon atoms, including polyhydric alcohols, such as glycol and glycerol, aromatic and aliphatic amines, ketones, such as acetone and methyl ethyl ketone, ethers, such as tetrahydrofuran and dioxane, and solvents, such as dimethylformamide and dimethyl sulfoxide.
  • Aliphatic alcohols, in particular ethyl alcohol and isopropyl alcohol are preferably used as solvents.
  • the solvents can be used in pure form or as mixtures with water. In the case of aqueous mixtures, concentrations of the solvent in the water of 40 and 60% can be considered. Based on the plant fiber material to be digested, it is preferred to work with a two to five times the volume of extractant.
  • the impregnation can be carried out at atmospheric pressure, which is preferred, or at overpressure. It can be carried out at room temperature or at an elevated temperature, a temperature between 40 and 80 ° C., in particular about 60 ° C., being preferred.
  • extraction is preferably carried out at temperatures between 130 and 210 ° C., in particular between 180 and 200 ° C.
  • the pressure in the reactor is between 1 and 40 bar, preferably between 15 and 25 bar.
  • the extraction liquid emerging from the reactor loaded with the substances extracted from the vegetable fiber material, is broken down into its constituent parts, i.e. essentially lignin, hemicellulose and solvent, separated.
  • the solvent preferably the alcohol
  • the solvent can be removed in a simple manner by distillation, stripping or flashing.
  • the remaining aqueous phase which contains lignin and hemicellulose, can be separated into its constituents, for example, by causing the lignin to precipitate out by shifting the concentration by removing the alcohol and by lowering the temperature, and centrifuging it in a suitable manner, for example using a screw press or a heavy phase separator is isolated.
  • the remaining hemicelluloses can then in turn be subjected to a clean presentation and further processing.
  • the impregnation of the plant fiber material which is usually in the form of wood chips, is important.
  • the impregnation in the present process can be carried out in a simple manner.
  • impregnation essentially fulfills the following functions.
  • Non-condensable gases and terpenes are expelled from the wood chips, so that there is no influence on the heat transfer and the diffusion of the cooking chemicals into the wood chips.
  • the wood chips adsorb condensate vapor, increasing the density at the same time.
  • the moisture displaces air from the wood chip surface.
  • the pre-impregnation of wood chips is usually carried out as follows in terms of process technology: the wood chips are introduced into a so-called steaming container via a metering device. Here, the wood chips are treated with saturated steam at pressures of 1 to 3 bar. The steam pretreatment is carried out for the reasons mentioned above.
  • the steam-heated chips are then transported to an impregnation tank. This is where the actual impregnation with cooking liquor begins.
  • the wood chips saturated with cooking liquor are then hydraulically pumped out of the impregnation tank by means of a high-pressure conveying device into an inclined separation tube at the head of the reactor.
  • the wood chips are transported into the reactor head by means of a screw conveyor.
  • the excess impregnation liquor is returned to the impregnation tank via a cylindrical sieve located in the separation tube.
  • the organic solvent removes the terpenes and resins that interfere with the penetration of the digestion liquid. For this reason, the use of a damping device operated under positive pressure can be dispensed with entirely. It goes without saying that the method according to the invention can nevertheless be used to dampen the wood chips.
  • the entire impregnation device can be reduced to an inclined impregnation tube located at the head of the reactor.
  • the wood chips are pushed upwards by means of a screw in the riser pipe filled with extraction liquid.
  • a further improvement in the impregnation is achieved by preheating the extraction liquid, for example with saturated steam, to temperatures of approximately 60 ° C.
  • the residence time of the chips in the impregnation zone is, for example, between 1 and 15 minutes, preferably 2 to 5 minutes, depending on the throughput.
  • the wood chips are then sufficiently impregnated with extraction liquid to ensure immediate immersion in the cooking zone. Due to the pressure-free impregnation with the organic solvent, a uniform concentration distribution of the solvent in the raw material is achieved and thus a defined starting point for the extraction stage is achieved.
  • the chips are introduced against the high pressure prevailing in the extraction vessel, preferably by means of a pressure lock controlled in time. It is advantageous to apply pressure, preferably by means of steam, to the pressure lock in order to keep the pressure difference between the pressure lock and the reactor low and thereby avoid pressure fluctuations in the reactor. If the pre-impregnation is carried out without pressure and the reactor operates at 18 bar, it is advantageous, for example, to introduce steam at 16 bar into the pressure lock.
  • the impregnated wood chips can then be easily pressed under the liquid level in the extraction reactor using an insertion device, preferably a screw.
  • the introduction device furthermore means that the wood chips are forcibly conveyed through the reactor. Due to the pre-impregnation and the forced conveyance, there is certainly no formation of wood chip bridges at the entry point and thus a blockage of the material flow.
  • the cooker can be divided into four reaction zones.
  • the first zone is an impregnation zone.
  • an impregnation zone is necessary despite the pre-impregnation, to achieve perfect saturation of the wood chips with cooking chemicals. Without an absolutely uniform pre-impregnation, black boiling occurs due to the lignin condensation that runs parallel to the lignin degradation.
  • the wood chips are brought to the desired cooking temperature in the heating zone following the impregnation zone. This is followed by the cooking zone in which the actual lignin degradation takes place. This is followed by a washing and cooling zone, in which the dissolved decomposition components are removed by countercurrent extraction with hot water. The wash water is used as a quench liquid to stop the chemical degradation reaction.
  • the reactor comprises only two zones, namely a cooking zone and a washing zone.
  • the wood chips are introduced into the cooking liquid at the top of the reactor, working at extraction liquid temperatures between 130 and 210 ° C. Cooking takes place in countercurrent, the delignification of the wood chips starting practically immediately upon contact with the hot extraction liquid. To achieve sufficient delignification rates, it is necessary to reach a sufficiently high temperature of the wood chips as quickly as possible. Lignin degradation by means of organic solvents or solvent / water mixtures is essentially thermal radical degradation and only achieves a rate that is sufficient for practical use at higher temperatures. However, since the lignin condensation and insolubilization begins at low temperatures, a heating-up period that is too long means that the lignin can only be extracted incompletely. The necessary rapid heating of the wood chips takes place in the method according to the invention due to the guidance of the impregnated wood chips in countercurrent to the hot extraction liquid.
  • the fresh extraction liquid is preferably fed in from the periphery of the reactor through a ring line.
  • extraction liquid can be fed in the middle of the reactor, for example via a hollow shaft.
  • the extraction liquid which rises upward in counterflow to the wood chips, is drawn off at the top of the reactor.
  • the organic solvent is recovered by distillation and condensation and recycled.
  • washing liquid which heats up in contact with the wood chips migrating downward.
  • the feed is preferably carried out via a peripheral ring line and / or a hollow shaft arranged in the reactor axis. Due to the high rate of diffusion of organic solvents, the solvent is practically completely removed from the largely delignified material during countercurrent washing of the wood chips. In the middle of the reactor, the washing liquid loaded with solvent and degradation products is generally drawn off together with part of the hot cooking liquid.
  • Solvent is preferably added to the removed washing liquid, for example by means of a metering pump, in such an amount that the desired composition of the extraction liquid is achieved again.
  • the extraction liquid is then brought to the required temperature, for example via a heat exchanger, and fed in via a peripheral ring line and / or a hollow shaft in the middle of the reactor.
  • washing liquid is not used for quenching the reaction, but rather is a component of the extraction liquid fed into the reactor.
  • Fluctuations in the process and the raw material, which cause changes in the composition of the extraction liquid, can easily be compensated for in the method according to the invention.
  • the chips are washed in countercurrent with pure water at a relatively high temperature. Because of the low concentration of wash water in organic solvent, the wash is much more effective than a wash using pure extractant as the washing liquid.
  • the digested material is usually discharged via a blow tank, washed again if necessary, and then sorted and processed in the usual way.
  • the single figure shows a flow diagram of the impregnation, extraction, washing and separation step of the process according to the invention.
  • the plant fiber material for example wood chips
  • the impregnator 1 which operates at atmospheric pressure and at a temperature of 600C, via the insertion device 16.
  • An ethanol-water mixture is fed to the impregnator via line 17.
  • the impregnated wood chips are conveyed upwards by means of the screw conveyor 18 through the inclined impregnator and fed to a pressure lock 2 via a discharge device 19.
  • the pressurized wood chips are then introduced into the reactor 3 above.
  • the chips are pressed by the vertically arranged screw 20 below the liquid level and through the reactor led below. On their way through the reactor, the chips are first flowed through by hot extraction liquid in countercurrent, the lignin and other cellulose companions which dissolve being pulled out of the chips by diffusion and carried away by the upwardly flowing extraction liquid.
  • the extraction liquid enriched with extract leaves the reactor via line 10.
  • the extraction liquid is then fed via a cooler 23 to a waste-gas relaxation vessel 24.
  • the solvent vapors released are condensed in a vapor condenser 25 and the solvent is recirculated via line 33 to the process.
  • the remaining aqueous solution of hemicelluloses and lignin is fed to a screw press 28 by a pump 26 via a further cooler 27.
  • a centrifuge or a heavy phase separator can replace the screw press.
  • the lignin precipitates in the screw press and is separated from the hemicelluloses.
  • the hemicelluloses and the lignin, which are drawn off via lines 29 and 30, can then be sent separately for further processing.
  • the dissolution of the cellulose companions is complete.
  • the cooking liquid is washed out of the digested material in the subsequent washing zone 5 by ascending water and drawn off with it in the middle of the reactor via outlet 8, line 11 and pump 21.
  • Fresh solvent is metered in via line 15 and, after heating in the heat exchanger 14, it is fed in as an extraction liquid via lines 13, 13 'through the hollow shaft 22 reaching into the top of the reactor through feed 9 in the middle of the reactor and via ring line 31.
  • Fresh solvent is fed to the process via line 34.
  • the washed-out pulp is withdrawn from the reactor at the end of the washing zone 5 via outlet 7. Washing liquid in the form of water is fed to the reactor at the reactor bottom via the peripheral ring line 32 and / or the hollow shaft 6.
  • cellulose of excellent quality and bleachability are obtained, which are ideally suited as a raw material for papermaking.
  • Hemicelluloses and lignin are obtained in pure form and can be used in many different ways as valuable raw materials.

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  • Paper (AREA)
  • Extraction Or Liquid Replacement (AREA)
  • Formation And Processing Of Food Products (AREA)
  • General Preparation And Processing Of Foods (AREA)
EP79105195A 1978-12-20 1979-12-14 Verfahren und Vorrichtung zum kontinuierlichen Aufschliessen von Pflanzenfasermaterial Expired EP0012960B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT79105195T ATE1914T1 (de) 1978-12-20 1979-12-14 Verfahren und vorrichtung zum kontinuierlichen aufschliessen von pflanzenfasermaterial.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19782855052 DE2855052A1 (de) 1978-12-20 1978-12-20 Verfahren und vorrichtung zum kontinuierlichen aufschliessen von pflanzenfasermaterial
DE2855052 1978-12-20

Publications (2)

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EP0012960A1 EP0012960A1 (de) 1980-07-09
EP0012960B1 true EP0012960B1 (de) 1982-12-01

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ID=6057775

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EP79105195A Expired EP0012960B1 (de) 1978-12-20 1979-12-14 Verfahren und Vorrichtung zum kontinuierlichen Aufschliessen von Pflanzenfasermaterial

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EP (1) EP0012960B1 (enrdf_load_stackoverflow)
AT (1) ATE1914T1 (enrdf_load_stackoverflow)
BR (1) BR7908189A (enrdf_load_stackoverflow)
CA (1) CA1111694A (enrdf_load_stackoverflow)
DE (2) DE2855052A1 (enrdf_load_stackoverflow)
FI (1) FI69130C (enrdf_load_stackoverflow)
PL (1) PL220500A1 (enrdf_load_stackoverflow)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102009051884A1 (de) * 2009-11-04 2011-05-05 Blue Globe Energy Gmbh Bioraffinerie-Verfahren

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT373303B (de) * 1981-08-06 1984-01-10 Chemiefaser Lenzing Ag Verfahren zur herstellung von zellstoffen mit niedrigem ligningehalt
AT373932B (de) * 1981-11-12 1984-03-12 Chemiefaser Lenzing Ag Verfahren zur aufarbeitung von gebrauchter aufschlussfluessikgeit sowie anlagen zur durchfuehrung dieses verfahrens
DE3212767A1 (de) * 1982-04-06 1983-10-06 Nicolaus Md Verwaltungsges Verfahren und reaktor zum kontinuierlichen aufschliessen von pflanzenfasermaterial
DE3339449A1 (de) * 1983-10-31 1985-05-09 MD Verwaltungsgesellschaft Nicolaus GmbH & Co. KG, 8000 München Verfahren zur gewinnung von lignin aus alkalischen lignin-loesungen
US5788812A (en) * 1985-11-05 1998-08-04 Agar; Richard C. Method of recovering furfural from organic pulping liquor
AT385061B (de) * 1985-11-29 1988-02-10 Neusiedler Ag Verfahren zur gewinnung von zellstoff aus pflanzenfasermaterial
DE4103572C2 (de) * 1991-02-06 1995-11-23 Organocell Ges Fuer Zellstoff Verfahren zum Delignifizieren von Pflanzenfasermaterial
DE69816478T2 (de) * 1997-09-15 2004-05-27 Melville, Gordon Brown Verfahren zur herstellung von zellstoff
MY137982A (en) * 1999-08-11 2009-04-30 Startech Internat Group Ltd Integrated process for treating oil palm biomass wastes

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE532741C (de) * 1929-11-02 1931-09-08 Kurt Von Tayenthal Dr Ing Verfahren zum Aufschluss von Pflanzenfaserstoffen
GB945957A (en) * 1960-02-08 1964-01-08 Ass Pulp & Paper Mills Continuous pulping process
US3585104A (en) * 1968-07-29 1971-06-15 Theodor N Kleinert Organosolv pulping and recovery process
DE2644155C2 (de) * 1976-09-30 1978-07-27 Theodor N. Dr. Pointe Claire Quebec Kleinert (Kanada) Kontinuierliches Aufschluß- und Ruckgewinnungsverfahren für pflanzliche Faserrohstoffe zur Herstellung von Zellstoff im organischen Lösungsmittel
CA1131415A (en) * 1978-11-27 1982-09-14 Bau- Und Forschungsgesellschaft Thermoform A.G. Pulping of lignocellulose with aqueous methanol/ catalyst mixture

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102009051884A1 (de) * 2009-11-04 2011-05-05 Blue Globe Energy Gmbh Bioraffinerie-Verfahren

Also Published As

Publication number Publication date
FI793985A7 (fi) 1980-06-21
ATE1914T1 (de) 1982-12-15
CA1111694A (en) 1981-11-03
BR7908189A (pt) 1980-07-22
FI69130C (fi) 1985-12-10
PL220500A1 (enrdf_load_stackoverflow) 1980-12-01
DE2855052A1 (de) 1980-06-26
EP0012960A1 (de) 1980-07-09
DE2964181D1 (en) 1983-01-05
FI69130B (fi) 1985-08-30

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