CA1111694A - Process and apparatus for continuously digesting plant fiber material - Google Patents
Process and apparatus for continuously digesting plant fiber materialInfo
- Publication number
- CA1111694A CA1111694A CA342,248A CA342248A CA1111694A CA 1111694 A CA1111694 A CA 1111694A CA 342248 A CA342248 A CA 342248A CA 1111694 A CA1111694 A CA 1111694A
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- Prior art keywords
- reactor
- plant fiber
- fiber material
- liquor
- zone
- Prior art date
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Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C3/00—Pulping cellulose-containing materials
- D21C3/20—Pulping cellulose-containing materials with organic solvents or in solvent environment
Abstract
ABSTRACT OF THE DISCLOSURE
A process and an apparatus for continuously digest-ing plant fiber material are described, the plant fiber material being treated with an organic solvent at temp-eratures of 130 - 210°C in a counter-current manner. The plant fiber material is impregnated with an organic sol-vent in an impregnating means and is positively conducted in a downward direction through the reactor. An organic solvent is introduced into the middle reactor zone as an extraction liquor and is conducted upwardly to the plant fiber material in a counter-current. Water is supplied in the bottom reactor zone as a wash liquor and is con-ducted upwardly to the plant fiber material in a counter-current. It is withdrawn in the middle reactor zone. The laden extraction liquor is separated into the essential components lignin, hemicellulose and solvent.
A process and an apparatus for continuously digest-ing plant fiber material are described, the plant fiber material being treated with an organic solvent at temp-eratures of 130 - 210°C in a counter-current manner. The plant fiber material is impregnated with an organic sol-vent in an impregnating means and is positively conducted in a downward direction through the reactor. An organic solvent is introduced into the middle reactor zone as an extraction liquor and is conducted upwardly to the plant fiber material in a counter-current. Water is supplied in the bottom reactor zone as a wash liquor and is con-ducted upwardly to the plant fiber material in a counter-current. It is withdrawn in the middle reactor zone. The laden extraction liquor is separated into the essential components lignin, hemicellulose and solvent.
Description
MD-Papierfabriken Heinrich Nicolaus GmbH
Ostenstr. 5 8060 Dachau A Process and Apparatus for Continuously Digesting Plant ~iber Ma-terial ~ACKGROUND OF lHE I~VE~ION
~his invention relates to a process and an apparatus for ~25 continuously digesting plant fiber material with an or-ganic solven-t.
~he economically important processes for digesting cellu-lose-containing raw fiber substances currently operate according to the sulfate or sulfite process.
~ssential disadvantages of these process, however~ are the required quantities of approximately 800 to 1000 tons per day for economical and rational operation as well as the enormous amount of environmental pollution in the form o~
waste water and exhaust gases, particularly because these ` contain sulfur compounds.
DESCRIPTION 0~ THE PRIOR ART
The possibility of digesting cellulose-containing plant fiber materials with organic solvents was already recited in US patent specification 1,856,567.
German laying-open print D~-OS 2,637,~49 describes a sol-vent extraction process for producing cellulose pulp, in which lignin is extracted from finely divided fibrous plant material at elevated temperature and pressure using an aque-ous solution of a lower aliphatic alcohol. This process op-erates with a plurality of batch extraction vessels, a ser~
ies of working steps succeeding one another in each extrac-tion vessel. ~his known process, however, is not suitable for the ccntinuous, economical production of pulp from plant fiber material. Ihe prime costs are disproportionate-ly high owing to the large number of extraction vessels re-quired. In particular, unless disproportionately large amounts of solvent are used, the heating interval per charge is very long so -that hydrolysis of the cellulose and hemi-cellulose commences even before the hlgh temperature is at-tained which is required to dissolve the lignin. ~or this reason, it is not possible to obtain pulp with sufficient strength for paper production using this known process.
US patent specification 3,5859104 and German opposition print DE-AS 2,64~,155 teach continuous digesting and re-covery processes for raw plant fiber materials for pulp production using organic solvents. No pre-impregnation is employed in these processes. ~or this reason, the flow o~ the material is easily blocked, particularly since pos-iti~e or forced transport through the reactor is not en-visioned. In the known processes, the digested material is cooked and then washed with cold organic solvent. Wash-ing with cold solvent, however, does not remove residual lignin. The organic solvent is subsequently pressed out of the digested material in a worm extruder. The digested material is thereafter washed with an aqueous sodium hydroxide solution in a separate means~ ~his solution is finally pressed out of the material in a second worm extruder. ~his approach is hardly effective~ but very expensive. In particular, the necessity of driving the organic solvent out of the cold~ digested material re-sults in a higher expenditure of energy.
SUMMARY 0~ ~HE IMVEN~ION
~he object of the invention is to provide a process and an apparatus for continuously digesting plant fiber mater-ial with orgarlic solvent, the essential components of -the plant fiber material9 i.e. lignin7 hemicellulose and cel-1~ lulose being separated and extracted in pure form. ~his process and apparatus operates economically on a large industrial scale 9 iS characterized by a simple procedur-al approach, in particularly avoiding the afore-mentioned drawbacks of the known processes, and yields a high-grade pulp adapted for easy bleachingO
~he subject matter of the invention is a process for con-tinuously digesting plant fiber material wherein the plant fiber material is treated with an organic solvent at temp-~5 eratures of 130 to 210C in a counter-current manner9 which ` is characterized in that the plant fiber material is impreg-nated with an organic solvent in an impregnating meansV tha-t the impregnated plant fiber material is introduced in the ` top reactor zone by a feeding means and is conducted posi-tively thereby in a downward direction, that cellulose is produced in the bottom reactor zone, that organic solvent at a temperature between 130 and 210~ is introduced into the middle reactor zone as an extr~tion liquor, is conduc-ted upwardly to the plant fiber material in a counter-cur-rent and is withdrawn at the top reactor zone~ and that water is supplied in the bottom reactor zone as a wash liquor, is conducted upwardly to the plant fiber material ~ `~
in a counter-current and is withdrawn in the middle re-actor zone and that the laden extraction llquor i5 gep-arated into the essential components lignin, hemicellu-lose and solvent.
~he subject matter of the invention is furthermore an apparatus for continuously digesting plant fiber material with an organic solvent, said apparatus comprising an impregnating means, a reactor for digesting the plant fiber material, means for washing the digested plant fi-ber material and separa-ting means, which is characterized in that the impregnating means, in which the plant fiber material is impregnated with an organic solvent, is de-signed as a screw conveyor and communicates directly with the top reactor zone through a pressurized lock, that a digesting zone and a washing zone are provided integrally in said reactor3 the reactor having in its base one or more inlet ports for the wash liquor and a discharge port for the digested plant fiber material, an outlet in the middle reactor zone for the wash liquor and one or more inlet ports for the extraction liquor, a feeding means in the top reactor zone for supplying the plant fiber mater-ial as well as an outlet for the laden extraction liquor, and that separating means are provided for extracting lig-nin, hemicellulose and solvent.
The advantages of the inventive process are to be seen in particular in the fact that economical quantities are at-tained with as little as 50 to 100 tons per day, that the rawsubstanceæ contained in addition to cellulose in the raw material, i.e. hemicellulose and lignin, are obtained primarily in their native form, and that the organic sol-vents used for extraction can be recovered and recycled `- by simple distillation and subsequent condensation, for example.
The continuous recycling of the solvent used is prac-tically free of losses.
The process is suitable for all cellulose-con-taining raw materials which can be pumped and poured. In particular~
possible raw materials are all na-tive and tropical types of wood9 as well as annular plants such as straw, hay and bagasse.
~he cellulose obtained with the aid of the inventive pro-cess is excellent for paper producing owing to its high quality.
~he inventive process, however, also successfully produces in addition to cellulose the other essential components of the plant fiber material in their pure, native form so that these products are available for further processing in many different sectors.
In the case of the digestion processes which up until now ha~e been the only ones employed on a large scale, i e.
the sulfite and sulfate processes, the hemicelluloses and the lignin accumulated in the form of derivatives which, however, were unsuitable as raw materials for further pro-cessing. ~hese substances, valueable in themselves, have hitherto been trea-ted or burned as being nothing better than waste products.
~y contrast, the inventive process for the first time per-mits the other essential components, i.e. lignin and hemi-celluloses, to be extracted in the form o~ pure, valueable raw materials.
~he hemicelluloses are suitable for a multitude of applica-tions, their use being emphasized in particular in -the fol-lowing areas: sugar production, especially sorbitol and man-nitol; the production of -thickening agents, adhesives) smooth-ing and thickening agents for the paper~ textile and varnish industry; the further processing to form alcohol by fermen-tation. It should be emphasi~ed that it can be advantageous ~L 3 ~
~ 6 --to recycle the alcohol obtained from the hemicelluloses as a solvent in the inventive proces~.
Ihe inventive process succeeds in extracting lignin in its native and substantially pure form. ~ignin is an ex-tremely valueable raw material. It accumulates during the process as polyol and is especially suitable for the production of synthetic resins. In particular~ a reaction with aldehydes is feasible. Special emphasis ig placed on polyurethanes, acetal resins, epoxy resins and phenol resins as synthetic resins which can be obtained star-ting with lignin~
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Organic solvents are employed as the extraction liquor, ~he - organic solvents should be miscible preferably with water in any arbitrary ratio Of special interest are aliphatic alcohols with 1 - 6 carbon atoms, including polyvalent al-cohols such as glycol and glycerin, aromatic and aliphatic amines, ketones, such as acetone and methylethyl ketone, ethers, such as tetrahydrofurane and dioxane, and solvents such as dimethyl formamide and dimethyl sulfoxide. Preferred as solvents are in particular aliphatic alcohols 9 especially ethyl alcohol and isopropyl alcohol~ ~he solvents can be added either in their pure form or as mixtures with water.
Possible aqueous mixtures can have solvent concentrations in water amounting to 10 - 100 %, preferably between 40 and ~` 60 %.
~he operation is preferably carried out with a two- to five-fold volume of extrac-tion agent, based on the plant fiber material to be digestedl Impregnation can be conducted at atmospheric pressure - this is preferred - although it can also occur under excess pres-~5 sure. It can be performed at room temperature or at an ele-vated temperature, a temperature between 40 and 80C, in particular about 60C, being preferred.
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~xtraction is performed in the digestion or ex-tract-ion zone preferably at temperatures between 13~ and 21~Cg in particular between 180 and 200C. ~he pressure in the reactor ranges betweèn 1 and 40 bar, preferably between 5 15 and 25 bar.
~he digested and washed plant fiber material, i,e. the cellulose, which is discharged from the reactor is pro-cessed further in the customary fashion so that it is 10 superfluous to go into further detail in this context.
lhe extraction liquor which is discharged from the re-actor and which is laden with the substances which were extracted from the plant fiber material is separated into 15 its components, i.e. essentially lignin, hemicellulose and solvent.
~he solvent, preferably the alcohol, can be separated easily by distillation, stripping or flash evaporation~
20 ~he remaining aqueous phase which contains the lignin and hemicellulose can be separated into its components, for instance, by causing the lignin -to be precipitated out of solution due to the concentration shift caused by lowering the temperature and by removal of the alcohol.
25 ~he lignin is then suitably isolated by means of a worm extruder~ a centrifuge or a heavy-phase separator? for example. ~he residual hemicelluloses can then be supplied in turn to purified production and further processing.
30 ~he impregnation of plant fiber material, which is in most cases present in the form of wood chips, is of importance in the inventive process. Unlike conventional, continuous pulping processes according to the sulfate or sulfite pro-cedures, in which an expensive impregnation is indispen-35 sible to ensure adequate pulp qualit~7 the impregnation can be carried out more simpl~ in the inventive processO
In the ~onventional sul~ate or ~ul~ite procedures, the impregnation operation basically fulfills the following functions. Uncondensable gases and terpenes are driven out of the wood chips so that the thermal transition and the diffusion of the digesting chemicals into the wood chips is not affected. ~he wood chip~ adsorb the condensate vapor and the density increases at the same time. ~he moisture displaces the air away from the sur-face of the wood chip. ~hese two effects ensure that the wood chips will sink into the digesting liquor relatively quickly. ~he tempera-ture and the moisture content of the wood chips are raised and evened out so that uniform di-gestion occurs in the reactor. The temperature and mois-; ture cause the wood chips to swell so that the impregna-~5 tion of the chips with the inorganic components of the digesting liquor is facilitated.
Inadequate impregnation of the wood chips, viz. when there is no digesting liquor present in the core of the chip while the wood chips are at the digesting temperature, can result in an excessive condensation of the lignin and thus in the notorious "~lack sludge".
The pre-impregnation of the wood chips is usually conduc-ted according to the following procedure. The wood chips are introduced into what is termed a steaming vessel via an appor-tioning or dosing means. ~he wood chips are treat--ed here with saturated steam at pressures ranging ~rom 1 to ~ bar. The steam pretreatment is carried out ~or the reasons already mentioned above. The wood chips heated by the steam are then transported into an impregnation tank where the actual impregnation with the digesting liquor commences. The wood chips saturated with digest-ing liquor are then hydraulically pumped out o~ the im-pregnation tank by means of a high~pressure conveyor into an inclined separation pipe in the -top reactor zone. The wood chips are conveyed into -the upper reactor ~one by means of a screw conveyor. Any excess impregna-tion liquor ~: ' will be returned to the impregnation tank by way of a cylindrical sieve located in the separation pipe.
Essential simplifications in the impregnating means re-sult in the case of the inventive process, where solvents or solvent/water mixtures are utilized instead of inor-ganic digestive liquors. ~he essential advantage of the solvent/water mixtures is to be found in the considerably higher wetting rate of and diffusion into the wood chips compared to conventional digestive liquors based on solu-tions of inorganic salts.
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~erpenes and resins which disrupt and impair the penetra-tion of the digestive liquor are removed by the organic solvent. ~he use of a steaming means operated at excessive pressure can therefore be eliminated en-tirely~ It goes with-out saying that the wood chips can nevertheless be steamed in the inventive process if so desired.
~o achieve satisfactory impregnation with the organic sol-ven~, the entire impregnation device can be reduced to an inclined impregnating pipe located in the upper reactor zone. ~he wood chips are pushed upwardly by a screw in the ascending pipe which is filled with the extraction liquor.
Another improvement in the impregnation is achieved by pre-heating the extraction liquor, for example~ using saturated steam7 to temperatures of about 60C. '~he residence time of the wood chips in the impregnation zone amounts -to between 1 and 15 minutes per batch, for example, preferably 2 to 5 minutes. ~he wood chips are then adequately impregnated with extraction liquor to ensure immediate submersi,on in -the di-gesting zone. A uniform distribution of the concentration of the solvent in the raw material is achieved and thus a clearly defined starting basis for the extraction stage is obtained due to the pressureless impreg~lation with the or-ganic solvent.
~he wood chips are introduced against the high pressure pre-vailing in the extraction vessel preferably by means of a clock-controlled pressurized lock. It is advantageous to actuate the pressurized loc~ with a pressurized medium, preferably steam, in order to minimize the pressure dif-~erence between the pressurized lock and the reac-tor, there-by avoiding pressure fluctuations in the reactor. If the pre-impre~nation is conducted under zero pressure and if the re-actor operates at 18 bar, it is advantageous, for ins-tance, to introduce steam with 16 bar pressure into the pressurized lock.
~he impregnated wood chips can be submerged beneath the li~uor level in the extraction reactor without any prob-lems by means of a feeding means, advantageously a screw.
~his feeding means also causes the wood chips to be con-veyed posi-tively through the reactor. lhe pre-impregnation and the positive conveyance of the chips reliably ensures that no wood chip jams will be formed at the inlet port and thus no obstruc-tion to the ~low of the material will occur here.
In the continuous pulp digesting processes on a sulfite or sul~ate basis, the digester can be subdivided into four re-action zones. lhe first zone is an impregnation zone. An im-pregnation zone is necessary in the conventional sulfite or sulfate digesting process in spite o~ pre-impregnation in order -to achieve proper saturation of the wood chips with the digesting chemicals. Without absolutely uni~orm pre-im~
pregnation, the result will be "black sludge" owing to the lignin condensation which runs parallel to the lignin decom-position. ~he impregnation zone is followed by a heating zone in which the wood chips are heated to the desired di-gesting temperature. ~his is followed by the digestion zone in which the actual decomposition of lignin occurs~ ~his is followed in turn by the washing and cooling zones in which the dissolved decompositiorl products are removed by counter-current extraction with hot water. The wash water is also utilized as a quenching liquid to terminate the chemical decomposition reaction.
The procedure of the digestion reaction can be simplified substantially in the inventive process which uses an or-ganic solvent as the extraction liquor. ~he reactor in-cludes only two zones, i.e. a digesting ~one and a washing zone.
; ~o impregnation ~one is required owing to the easy impreg-nability of the wood chips with the organic solvent.
The wood chips are introduced into the digesting liquor in the upper reactor zone. ~he operation is carried out at ex-traction liquor temperatures between 130 and 210C. Diges-tion occurs in a counter-current manner, the delignification of the wood chips commencing at almost the very moment they come into contact with the hot extraction liquor. ~o achieve sufficient delignifica-tion rates9 it is necessary to reach an adequately high temperature of -the wood chips as quickly as possible. The lignin decomposition by means of organic solvents or solvent/water mixtures is essentially a radical, thermal decomposition reactor, although rates sufficient for practical use are only reached at elevated temperatures.
Since lignin condensation, thus rendering the wood chips in-soluble, occurs even at lower temperatures, an excessively ` long heating interval means tha-t the lignin can be extracted only imcompletely. ~he requisite, rapid heating of the wood chips is achieved in the inventive process by conveying the impregnated wood chips in a counter-current with respect to the ho-t extraction liquor.
The fresh ex-traction liquor is introduced in the inventive process preferably by means of an annular line from the periphery of the reactor. Instead of or, preferably9 in ad-dition to introducing the liquor from the reactor periphery~
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_ 12 -the extraction liquor can also be supplied into the middle of the reactor through a hollow shaft, for instance. ~he extraction liquor which ascends in a counter-current with respect to the wood chips is withdrawn in the top reactor zone. ~he organic solvent is recovered by distillation and condensation and is then recycled.
Water, which can be warm or cold, is supplied in the bottom reactor zone as the wash liquor which is heated when it comes into contact with the wood chips which ~igrate downwardly.
~he water is supplied preferably through a peripheral annu-lar line and/or a hollDw shaft located in the axis of the reactor. Owing to the high diffusion rate of the organic sol-vents, the solvent is almost completely removed from the ex-tensively delignified material in the wood chip counter-cur-rent~ lhe wash liquor which is laden with solvent and decom-position products is generally withdrawn together with part of the hot digesting liquor in the middle reactor zoneO
~he withdrawn wash liquor is admixed with a solvent by means of a dosage pump, for example, the amount of said solvent being such that the desired composition o~ -the extraction liquor is restored. ~he extraction liquor is then reheated to the requisite temperature, e.g. by a heat exchanger~
and is resupplied to the middle reactor zone through a per-ipheral, annular line and/or through a hollow shaf-t~
lhe gist of the inventive process is that the washing liquor does not serve to quench the reaction, but rather constitutes one component of the extraction liquor supplied to the reactor.
Any fluctuations in the process and in the raw material caused by alterations in the composition of the extraction liquor can be easily compensated for in the inventive pro-cess.
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It is also advantageous that the wood chips are washed in a counter-current with pure water at a relatively high temp-erature. Owing to the low concentration of organic solvent in the wash water, such a washing is much more effective than a washing in which pure extraction agent is used as the washing liquor.
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~he digested material is discharged as a rule by mean~ of a blast tank, can be rewashed if desired, then sorted in a conventional manner and processed further.
~RIE~ DESCRIP~ION 0~ IHE DRhWING
~he invention will now be explained in detail in the follow-ing with reference to the drawing, in which the sole figure shows a flow diagram of the impregnation9 extraction, washing and separation stages of the inventive process.
DESCRIP~ION 0~ ~HE PREFERRED EMBODIMENT
~he plant fiber material, e.g. wood chips, is introduced by a feeding means 16 into the impregnator 1 which oper~
ates at atmospheric pressure and a temperature of 60C.
An ethanol/water mixture is supplied to the impregnator through line l7. ~he perfused wood chips are conveyed in an upward direction through the inclined impregnator by means of the screw conveyor 18 and are supplied to a pressurized lock 2 by means of a discharge means 19. ~he pressurized wood chips are then introduced into the reac-; 30 tor 3 at the top thereof.
In the reactor, the wood chips are submerged beneath the level of the liquor by the vertical worm 20 and are then conducted downwar~ly through the reactor. During their movement through said reactor, the chips are first tra-versed in a counter-current by the hot extraction liquor.
- In so doing, the dissolving lignin and other cellulose ; associates are removed from the chips by diffusion and .
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are transported further by the ascending extraction liquor.
~he extraction liquor enriched with extract leaves the re-actor through line 10. The ex-traction liquor is supplied through a cooler 23 to a spent liquor ~epres~uri~ing ves-sel 24. ~he exhaust solvent vapors released are condensed in an exhaust vapor condenser 25 and the solvent recycled to the process through line 33.
~he residual aqueous solution consistin~ of hemicelluloses and lignin is supplied by a pump 26 through another cool-er 27 to a worm extruder 28. A centrifuge or a heavy-phase separator can also be used in place of the worm extruder.
~he lignin precipitates in the worm extruder at a lower temperature and is separated from the h~icelluloses. ~he hemicelluloses and the lignin, which are withdrawn via lines 29 and 30, can then be processed separately.
~he dissolution of the associated cellulose compounds is concluded at the end of the digesting zone 4. ~he digest-ing liquor is washed out of the digested material by as-cending water in the ensuing washing zone 5 and is with-drawn from the middle reactor ~one via the outlet 8, the line 11 and pump 21. ~rish solvent is added to the washing liquor via line 15 and, after being heated in the heat ex-changer 14, it is recycled as extraction liquor through lines 13, 13' and the hollow shaft 22 extending into the reactor at the top, through the inlet port 9 into the mid-dle of the reactor as well as through the annular pipe 31.
~resh solvent is supplied to the process via line 34O
~he washed pulp is discharged from the reactor at the end o~ the washing æone 5 via discharge port 7. ~he washing ~5 liquor is supplied to the reactor in the form of water via the peripheral, annular line 32 and/nr the hollow sha~'t 6 located in the bottom reactor zone.
It is self-evident that the individual material flows are controlled by means of suitable measuring and regu-lating means, ~he inventive process yields pulps of excellent quality and bleachability which are most suitable as the raw material for paper production. ~he hemicelluloses and lignin are obtained in pure form and can be utilized as valueable raw materials in a multitude of applica-tionsO
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Ostenstr. 5 8060 Dachau A Process and Apparatus for Continuously Digesting Plant ~iber Ma-terial ~ACKGROUND OF lHE I~VE~ION
~his invention relates to a process and an apparatus for ~25 continuously digesting plant fiber material with an or-ganic solven-t.
~he economically important processes for digesting cellu-lose-containing raw fiber substances currently operate according to the sulfate or sulfite process.
~ssential disadvantages of these process, however~ are the required quantities of approximately 800 to 1000 tons per day for economical and rational operation as well as the enormous amount of environmental pollution in the form o~
waste water and exhaust gases, particularly because these ` contain sulfur compounds.
DESCRIPTION 0~ THE PRIOR ART
The possibility of digesting cellulose-containing plant fiber materials with organic solvents was already recited in US patent specification 1,856,567.
German laying-open print D~-OS 2,637,~49 describes a sol-vent extraction process for producing cellulose pulp, in which lignin is extracted from finely divided fibrous plant material at elevated temperature and pressure using an aque-ous solution of a lower aliphatic alcohol. This process op-erates with a plurality of batch extraction vessels, a ser~
ies of working steps succeeding one another in each extrac-tion vessel. ~his known process, however, is not suitable for the ccntinuous, economical production of pulp from plant fiber material. Ihe prime costs are disproportionate-ly high owing to the large number of extraction vessels re-quired. In particular, unless disproportionately large amounts of solvent are used, the heating interval per charge is very long so -that hydrolysis of the cellulose and hemi-cellulose commences even before the hlgh temperature is at-tained which is required to dissolve the lignin. ~or this reason, it is not possible to obtain pulp with sufficient strength for paper production using this known process.
US patent specification 3,5859104 and German opposition print DE-AS 2,64~,155 teach continuous digesting and re-covery processes for raw plant fiber materials for pulp production using organic solvents. No pre-impregnation is employed in these processes. ~or this reason, the flow o~ the material is easily blocked, particularly since pos-iti~e or forced transport through the reactor is not en-visioned. In the known processes, the digested material is cooked and then washed with cold organic solvent. Wash-ing with cold solvent, however, does not remove residual lignin. The organic solvent is subsequently pressed out of the digested material in a worm extruder. The digested material is thereafter washed with an aqueous sodium hydroxide solution in a separate means~ ~his solution is finally pressed out of the material in a second worm extruder. ~his approach is hardly effective~ but very expensive. In particular, the necessity of driving the organic solvent out of the cold~ digested material re-sults in a higher expenditure of energy.
SUMMARY 0~ ~HE IMVEN~ION
~he object of the invention is to provide a process and an apparatus for continuously digesting plant fiber mater-ial with orgarlic solvent, the essential components of -the plant fiber material9 i.e. lignin7 hemicellulose and cel-1~ lulose being separated and extracted in pure form. ~his process and apparatus operates economically on a large industrial scale 9 iS characterized by a simple procedur-al approach, in particularly avoiding the afore-mentioned drawbacks of the known processes, and yields a high-grade pulp adapted for easy bleachingO
~he subject matter of the invention is a process for con-tinuously digesting plant fiber material wherein the plant fiber material is treated with an organic solvent at temp-~5 eratures of 130 to 210C in a counter-current manner9 which ` is characterized in that the plant fiber material is impreg-nated with an organic solvent in an impregnating meansV tha-t the impregnated plant fiber material is introduced in the ` top reactor zone by a feeding means and is conducted posi-tively thereby in a downward direction, that cellulose is produced in the bottom reactor zone, that organic solvent at a temperature between 130 and 210~ is introduced into the middle reactor zone as an extr~tion liquor, is conduc-ted upwardly to the plant fiber material in a counter-cur-rent and is withdrawn at the top reactor zone~ and that water is supplied in the bottom reactor zone as a wash liquor, is conducted upwardly to the plant fiber material ~ `~
in a counter-current and is withdrawn in the middle re-actor zone and that the laden extraction llquor i5 gep-arated into the essential components lignin, hemicellu-lose and solvent.
~he subject matter of the invention is furthermore an apparatus for continuously digesting plant fiber material with an organic solvent, said apparatus comprising an impregnating means, a reactor for digesting the plant fiber material, means for washing the digested plant fi-ber material and separa-ting means, which is characterized in that the impregnating means, in which the plant fiber material is impregnated with an organic solvent, is de-signed as a screw conveyor and communicates directly with the top reactor zone through a pressurized lock, that a digesting zone and a washing zone are provided integrally in said reactor3 the reactor having in its base one or more inlet ports for the wash liquor and a discharge port for the digested plant fiber material, an outlet in the middle reactor zone for the wash liquor and one or more inlet ports for the extraction liquor, a feeding means in the top reactor zone for supplying the plant fiber mater-ial as well as an outlet for the laden extraction liquor, and that separating means are provided for extracting lig-nin, hemicellulose and solvent.
The advantages of the inventive process are to be seen in particular in the fact that economical quantities are at-tained with as little as 50 to 100 tons per day, that the rawsubstanceæ contained in addition to cellulose in the raw material, i.e. hemicellulose and lignin, are obtained primarily in their native form, and that the organic sol-vents used for extraction can be recovered and recycled `- by simple distillation and subsequent condensation, for example.
The continuous recycling of the solvent used is prac-tically free of losses.
The process is suitable for all cellulose-con-taining raw materials which can be pumped and poured. In particular~
possible raw materials are all na-tive and tropical types of wood9 as well as annular plants such as straw, hay and bagasse.
~he cellulose obtained with the aid of the inventive pro-cess is excellent for paper producing owing to its high quality.
~he inventive process, however, also successfully produces in addition to cellulose the other essential components of the plant fiber material in their pure, native form so that these products are available for further processing in many different sectors.
In the case of the digestion processes which up until now ha~e been the only ones employed on a large scale, i e.
the sulfite and sulfate processes, the hemicelluloses and the lignin accumulated in the form of derivatives which, however, were unsuitable as raw materials for further pro-cessing. ~hese substances, valueable in themselves, have hitherto been trea-ted or burned as being nothing better than waste products.
~y contrast, the inventive process for the first time per-mits the other essential components, i.e. lignin and hemi-celluloses, to be extracted in the form o~ pure, valueable raw materials.
~he hemicelluloses are suitable for a multitude of applica-tions, their use being emphasized in particular in -the fol-lowing areas: sugar production, especially sorbitol and man-nitol; the production of -thickening agents, adhesives) smooth-ing and thickening agents for the paper~ textile and varnish industry; the further processing to form alcohol by fermen-tation. It should be emphasi~ed that it can be advantageous ~L 3 ~
~ 6 --to recycle the alcohol obtained from the hemicelluloses as a solvent in the inventive proces~.
Ihe inventive process succeeds in extracting lignin in its native and substantially pure form. ~ignin is an ex-tremely valueable raw material. It accumulates during the process as polyol and is especially suitable for the production of synthetic resins. In particular~ a reaction with aldehydes is feasible. Special emphasis ig placed on polyurethanes, acetal resins, epoxy resins and phenol resins as synthetic resins which can be obtained star-ting with lignin~
:
Organic solvents are employed as the extraction liquor, ~he - organic solvents should be miscible preferably with water in any arbitrary ratio Of special interest are aliphatic alcohols with 1 - 6 carbon atoms, including polyvalent al-cohols such as glycol and glycerin, aromatic and aliphatic amines, ketones, such as acetone and methylethyl ketone, ethers, such as tetrahydrofurane and dioxane, and solvents such as dimethyl formamide and dimethyl sulfoxide. Preferred as solvents are in particular aliphatic alcohols 9 especially ethyl alcohol and isopropyl alcohol~ ~he solvents can be added either in their pure form or as mixtures with water.
Possible aqueous mixtures can have solvent concentrations in water amounting to 10 - 100 %, preferably between 40 and ~` 60 %.
~he operation is preferably carried out with a two- to five-fold volume of extrac-tion agent, based on the plant fiber material to be digestedl Impregnation can be conducted at atmospheric pressure - this is preferred - although it can also occur under excess pres-~5 sure. It can be performed at room temperature or at an ele-vated temperature, a temperature between 40 and 80C, in particular about 60C, being preferred.
`~
-- 7 ~
~xtraction is performed in the digestion or ex-tract-ion zone preferably at temperatures between 13~ and 21~Cg in particular between 180 and 200C. ~he pressure in the reactor ranges betweèn 1 and 40 bar, preferably between 5 15 and 25 bar.
~he digested and washed plant fiber material, i,e. the cellulose, which is discharged from the reactor is pro-cessed further in the customary fashion so that it is 10 superfluous to go into further detail in this context.
lhe extraction liquor which is discharged from the re-actor and which is laden with the substances which were extracted from the plant fiber material is separated into 15 its components, i.e. essentially lignin, hemicellulose and solvent.
~he solvent, preferably the alcohol, can be separated easily by distillation, stripping or flash evaporation~
20 ~he remaining aqueous phase which contains the lignin and hemicellulose can be separated into its components, for instance, by causing the lignin -to be precipitated out of solution due to the concentration shift caused by lowering the temperature and by removal of the alcohol.
25 ~he lignin is then suitably isolated by means of a worm extruder~ a centrifuge or a heavy-phase separator? for example. ~he residual hemicelluloses can then be supplied in turn to purified production and further processing.
30 ~he impregnation of plant fiber material, which is in most cases present in the form of wood chips, is of importance in the inventive process. Unlike conventional, continuous pulping processes according to the sulfate or sulfite pro-cedures, in which an expensive impregnation is indispen-35 sible to ensure adequate pulp qualit~7 the impregnation can be carried out more simpl~ in the inventive processO
In the ~onventional sul~ate or ~ul~ite procedures, the impregnation operation basically fulfills the following functions. Uncondensable gases and terpenes are driven out of the wood chips so that the thermal transition and the diffusion of the digesting chemicals into the wood chips is not affected. ~he wood chip~ adsorb the condensate vapor and the density increases at the same time. ~he moisture displaces the air away from the sur-face of the wood chip. ~hese two effects ensure that the wood chips will sink into the digesting liquor relatively quickly. ~he tempera-ture and the moisture content of the wood chips are raised and evened out so that uniform di-gestion occurs in the reactor. The temperature and mois-; ture cause the wood chips to swell so that the impregna-~5 tion of the chips with the inorganic components of the digesting liquor is facilitated.
Inadequate impregnation of the wood chips, viz. when there is no digesting liquor present in the core of the chip while the wood chips are at the digesting temperature, can result in an excessive condensation of the lignin and thus in the notorious "~lack sludge".
The pre-impregnation of the wood chips is usually conduc-ted according to the following procedure. The wood chips are introduced into what is termed a steaming vessel via an appor-tioning or dosing means. ~he wood chips are treat--ed here with saturated steam at pressures ranging ~rom 1 to ~ bar. The steam pretreatment is carried out ~or the reasons already mentioned above. The wood chips heated by the steam are then transported into an impregnation tank where the actual impregnation with the digesting liquor commences. The wood chips saturated with digest-ing liquor are then hydraulically pumped out o~ the im-pregnation tank by means of a high~pressure conveyor into an inclined separation pipe in the -top reactor zone. The wood chips are conveyed into -the upper reactor ~one by means of a screw conveyor. Any excess impregna-tion liquor ~: ' will be returned to the impregnation tank by way of a cylindrical sieve located in the separation pipe.
Essential simplifications in the impregnating means re-sult in the case of the inventive process, where solvents or solvent/water mixtures are utilized instead of inor-ganic digestive liquors. ~he essential advantage of the solvent/water mixtures is to be found in the considerably higher wetting rate of and diffusion into the wood chips compared to conventional digestive liquors based on solu-tions of inorganic salts.
.
~erpenes and resins which disrupt and impair the penetra-tion of the digestive liquor are removed by the organic solvent. ~he use of a steaming means operated at excessive pressure can therefore be eliminated en-tirely~ It goes with-out saying that the wood chips can nevertheless be steamed in the inventive process if so desired.
~o achieve satisfactory impregnation with the organic sol-ven~, the entire impregnation device can be reduced to an inclined impregnating pipe located in the upper reactor zone. ~he wood chips are pushed upwardly by a screw in the ascending pipe which is filled with the extraction liquor.
Another improvement in the impregnation is achieved by pre-heating the extraction liquor, for example~ using saturated steam7 to temperatures of about 60C. '~he residence time of the wood chips in the impregnation zone amounts -to between 1 and 15 minutes per batch, for example, preferably 2 to 5 minutes. ~he wood chips are then adequately impregnated with extraction liquor to ensure immediate submersi,on in -the di-gesting zone. A uniform distribution of the concentration of the solvent in the raw material is achieved and thus a clearly defined starting basis for the extraction stage is obtained due to the pressureless impreg~lation with the or-ganic solvent.
~he wood chips are introduced against the high pressure pre-vailing in the extraction vessel preferably by means of a clock-controlled pressurized lock. It is advantageous to actuate the pressurized loc~ with a pressurized medium, preferably steam, in order to minimize the pressure dif-~erence between the pressurized lock and the reac-tor, there-by avoiding pressure fluctuations in the reactor. If the pre-impre~nation is conducted under zero pressure and if the re-actor operates at 18 bar, it is advantageous, for ins-tance, to introduce steam with 16 bar pressure into the pressurized lock.
~he impregnated wood chips can be submerged beneath the li~uor level in the extraction reactor without any prob-lems by means of a feeding means, advantageously a screw.
~his feeding means also causes the wood chips to be con-veyed posi-tively through the reactor. lhe pre-impregnation and the positive conveyance of the chips reliably ensures that no wood chip jams will be formed at the inlet port and thus no obstruc-tion to the ~low of the material will occur here.
In the continuous pulp digesting processes on a sulfite or sul~ate basis, the digester can be subdivided into four re-action zones. lhe first zone is an impregnation zone. An im-pregnation zone is necessary in the conventional sulfite or sulfate digesting process in spite o~ pre-impregnation in order -to achieve proper saturation of the wood chips with the digesting chemicals. Without absolutely uni~orm pre-im~
pregnation, the result will be "black sludge" owing to the lignin condensation which runs parallel to the lignin decom-position. ~he impregnation zone is followed by a heating zone in which the wood chips are heated to the desired di-gesting temperature. ~his is followed by the digestion zone in which the actual decomposition of lignin occurs~ ~his is followed in turn by the washing and cooling zones in which the dissolved decompositiorl products are removed by counter-current extraction with hot water. The wash water is also utilized as a quenching liquid to terminate the chemical decomposition reaction.
The procedure of the digestion reaction can be simplified substantially in the inventive process which uses an or-ganic solvent as the extraction liquor. ~he reactor in-cludes only two zones, i.e. a digesting ~one and a washing zone.
; ~o impregnation ~one is required owing to the easy impreg-nability of the wood chips with the organic solvent.
The wood chips are introduced into the digesting liquor in the upper reactor zone. ~he operation is carried out at ex-traction liquor temperatures between 130 and 210C. Diges-tion occurs in a counter-current manner, the delignification of the wood chips commencing at almost the very moment they come into contact with the hot extraction liquor. ~o achieve sufficient delignifica-tion rates9 it is necessary to reach an adequately high temperature of -the wood chips as quickly as possible. The lignin decomposition by means of organic solvents or solvent/water mixtures is essentially a radical, thermal decomposition reactor, although rates sufficient for practical use are only reached at elevated temperatures.
Since lignin condensation, thus rendering the wood chips in-soluble, occurs even at lower temperatures, an excessively ` long heating interval means tha-t the lignin can be extracted only imcompletely. ~he requisite, rapid heating of the wood chips is achieved in the inventive process by conveying the impregnated wood chips in a counter-current with respect to the ho-t extraction liquor.
The fresh ex-traction liquor is introduced in the inventive process preferably by means of an annular line from the periphery of the reactor. Instead of or, preferably9 in ad-dition to introducing the liquor from the reactor periphery~
' `
; `
_ 12 -the extraction liquor can also be supplied into the middle of the reactor through a hollow shaft, for instance. ~he extraction liquor which ascends in a counter-current with respect to the wood chips is withdrawn in the top reactor zone. ~he organic solvent is recovered by distillation and condensation and is then recycled.
Water, which can be warm or cold, is supplied in the bottom reactor zone as the wash liquor which is heated when it comes into contact with the wood chips which ~igrate downwardly.
~he water is supplied preferably through a peripheral annu-lar line and/or a hollDw shaft located in the axis of the reactor. Owing to the high diffusion rate of the organic sol-vents, the solvent is almost completely removed from the ex-tensively delignified material in the wood chip counter-cur-rent~ lhe wash liquor which is laden with solvent and decom-position products is generally withdrawn together with part of the hot digesting liquor in the middle reactor zoneO
~he withdrawn wash liquor is admixed with a solvent by means of a dosage pump, for example, the amount of said solvent being such that the desired composition o~ -the extraction liquor is restored. ~he extraction liquor is then reheated to the requisite temperature, e.g. by a heat exchanger~
and is resupplied to the middle reactor zone through a per-ipheral, annular line and/or through a hollow shaf-t~
lhe gist of the inventive process is that the washing liquor does not serve to quench the reaction, but rather constitutes one component of the extraction liquor supplied to the reactor.
Any fluctuations in the process and in the raw material caused by alterations in the composition of the extraction liquor can be easily compensated for in the inventive pro-cess.
. .
It is also advantageous that the wood chips are washed in a counter-current with pure water at a relatively high temp-erature. Owing to the low concentration of organic solvent in the wash water, such a washing is much more effective than a washing in which pure extraction agent is used as the washing liquor.
'!
~he digested material is discharged as a rule by mean~ of a blast tank, can be rewashed if desired, then sorted in a conventional manner and processed further.
~RIE~ DESCRIP~ION 0~ IHE DRhWING
~he invention will now be explained in detail in the follow-ing with reference to the drawing, in which the sole figure shows a flow diagram of the impregnation9 extraction, washing and separation stages of the inventive process.
DESCRIP~ION 0~ ~HE PREFERRED EMBODIMENT
~he plant fiber material, e.g. wood chips, is introduced by a feeding means 16 into the impregnator 1 which oper~
ates at atmospheric pressure and a temperature of 60C.
An ethanol/water mixture is supplied to the impregnator through line l7. ~he perfused wood chips are conveyed in an upward direction through the inclined impregnator by means of the screw conveyor 18 and are supplied to a pressurized lock 2 by means of a discharge means 19. ~he pressurized wood chips are then introduced into the reac-; 30 tor 3 at the top thereof.
In the reactor, the wood chips are submerged beneath the level of the liquor by the vertical worm 20 and are then conducted downwar~ly through the reactor. During their movement through said reactor, the chips are first tra-versed in a counter-current by the hot extraction liquor.
- In so doing, the dissolving lignin and other cellulose ; associates are removed from the chips by diffusion and .
. . .
., .
`~
- 14 ~
are transported further by the ascending extraction liquor.
~he extraction liquor enriched with extract leaves the re-actor through line 10. The ex-traction liquor is supplied through a cooler 23 to a spent liquor ~epres~uri~ing ves-sel 24. ~he exhaust solvent vapors released are condensed in an exhaust vapor condenser 25 and the solvent recycled to the process through line 33.
~he residual aqueous solution consistin~ of hemicelluloses and lignin is supplied by a pump 26 through another cool-er 27 to a worm extruder 28. A centrifuge or a heavy-phase separator can also be used in place of the worm extruder.
~he lignin precipitates in the worm extruder at a lower temperature and is separated from the h~icelluloses. ~he hemicelluloses and the lignin, which are withdrawn via lines 29 and 30, can then be processed separately.
~he dissolution of the associated cellulose compounds is concluded at the end of the digesting zone 4. ~he digest-ing liquor is washed out of the digested material by as-cending water in the ensuing washing zone 5 and is with-drawn from the middle reactor ~one via the outlet 8, the line 11 and pump 21. ~rish solvent is added to the washing liquor via line 15 and, after being heated in the heat ex-changer 14, it is recycled as extraction liquor through lines 13, 13' and the hollow shaft 22 extending into the reactor at the top, through the inlet port 9 into the mid-dle of the reactor as well as through the annular pipe 31.
~resh solvent is supplied to the process via line 34O
~he washed pulp is discharged from the reactor at the end o~ the washing æone 5 via discharge port 7. ~he washing ~5 liquor is supplied to the reactor in the form of water via the peripheral, annular line 32 and/nr the hollow sha~'t 6 located in the bottom reactor zone.
It is self-evident that the individual material flows are controlled by means of suitable measuring and regu-lating means, ~he inventive process yields pulps of excellent quality and bleachability which are most suitable as the raw material for paper production. ~he hemicelluloses and lignin are obtained in pure form and can be utilized as valueable raw materials in a multitude of applica-tionsO
- . .
. ' ` ' ~
Claims (16)
1. In a process for continuously digesting plant fiber material wherein the plant fiber material is treated with an organic solvent at temperatures of 130 - 210°C in a counter-current manner, the improvement being that the plant fiber material is impregnated with an organic sol-vent in an impregnating means, that the impregnated plant fiber material is introduced in the top reactor zone by a feeding means and is positively conducted thereby in a downward direction, that cellulose is produced in the bot-tom reactor zone, that organic solvent at a temperature between 130 and 210°C is introduced into the middle reac-tor zone as an extraction liquor, is conducted upwardly to the plant fiber material in a counter-current and is withdrawn at the top reactor zone and that water is sup-plied at the bottom reactor zone as a wash liquor, is con-ducted upwardly to the plant fiber material in a counter-current and is withdrawn in the middle reactor zone and that the laden extraction liquor is separated into sub-stantially the components lignin, hemicellulose and solvent.
2. A process according to claim 1, wherein the organic solvent is used in the form of a mixture of organic sol-vent and water, having a solvent concentration of 10 -100 %, in particular between 40 and 60 %.
3. A process according to claim 1 or 2, wherein ethyl or isopropyl alcohol is used as the organic solvent.
4. A process according to claim 1, wherein impregnation occurs at atmospheric pressure.
5. A process according to claim 1, wherein impregnation occurs at an elevated temperature, in particular between 40 and 80°C.
6. A process according to claim 1, wherein impregnation is performed in a screw conveyor.
7. A process according to claim 1, wherein the extraction agent supplied to the middle reactor zone has a temperature between 180 and 200°C.
8. A process according to claim 1, wherein the wash liquor withdrawn from the middle reactor zone is admixed with an organic solvent and this mixture is recycled to the reactor as the extraction liquor.
9. A process according to claim 1, wherein the extraction liquor is introduced from the reactor periphery into the reactor interior and/or an annular line through a hollow shaft.
10. A process according to claim 1, wherein the extraction liquor is used in an amount corresponding to two-to five-times the volume of the plant fiber material.
11. An apparatus for continuously digesting plant fiber material with an organic solvent, said apparatus comprising an impregnating means, a reactor for digesting the plant fiber material, means for washing the digested plant fiber material and separating means, characterized in that the imprefnating means (1) in which the plant fiber material is impregnated with an organic solvent is designed as a screw conveyor and communicates directly with a top zone of the reactor through a pressurized lock (2), that a digesting zone (4) and a washing zone (5) are provided integrally in said reactor (3), the reactor (3) having in its base one or more inlet ports (6,32) for the wash liquor and a discharge port (7) for the digested plant fiber material, an outlet (8) in the middle reactor zone for the wash liquor and one or more inlet ports (9,31) for the
11. An apparatus for continuously digesting plant fiber material with an organic solvent, said apparatus comprising an impregnating means, a reactor for digesting the plant fiber material, means for washing the digested plant fiber material and separating means, characterized in that the imprefnating means (1) in which the plant fiber material is impregnated with an organic solvent is designed as a screw conveyor and communicates directly with a top zone of the reactor through a pressurized lock (2), that a digesting zone (4) and a washing zone (5) are provided integrally in said reactor (3), the reactor (3) having in its base one or more inlet ports (6,32) for the wash liquor and a discharge port (7) for the digested plant fiber material, an outlet (8) in the middle reactor zone for the wash liquor and one or more inlet ports (9,31) for the
Claim 11 continued.
extraction liquor, a feeding means (20) in the top reactor zone for supplying the plant fiber material as well as an outlet (10) for the laden extraction liquor, and that separating means (24,25,28) are provided for extracting lignin, hemicellulose and solvent.
extraction liquor, a feeding means (20) in the top reactor zone for supplying the plant fiber material as well as an outlet (10) for the laden extraction liquor, and that separating means (24,25,28) are provided for extracting lignin, hemicellulose and solvent.
12. An apparatus according to claim 11, wherein the outlet (8) communicates with the inlet parts (9,31) through lines (11,12,l3,13'). and a heat exchanger (14), an inlet (15) for admixing the organic solvent terminating in one of said lines (11,12,13,13').
13. An apparatus according to claim 11 or 12, wherein there is disposed in the reactor a hollow shaft (22) extending from the top to approximately the middle of said reactor and serving to supply additional extraction liquor through an inlet (9).
14. An apparatus according to claim 11, wherein another inlet (6) is provided in the middle of the reactor base in the form of a hollow shaft for supplying the wash liquor.
15. An apparatus according to claim 11, wherein the feeding means (20) is designed in the form of a screw conveyor.
16. An apparatus according to claim 11, wherein a spent liquor flash evaporator (24), a vapor condenser (25) and a worm extruder (28) are provided to separate the lignin, hemicellulose and the solvent.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19782855052 DE2855052A1 (en) | 1978-12-20 | 1978-12-20 | METHOD AND DEVICE FOR CONTINUOUSLY UNLOCKING PLANT FIBER MATERIAL |
| DEP2855052.9 | 1978-12-20 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1111694A true CA1111694A (en) | 1981-11-03 |
Family
ID=6057775
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA342,248A Expired CA1111694A (en) | 1978-12-20 | 1979-12-19 | Process and apparatus for continuously digesting plant fiber material |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP0012960B1 (en) |
| AT (1) | ATE1914T1 (en) |
| BR (1) | BR7908189A (en) |
| CA (1) | CA1111694A (en) |
| DE (2) | DE2855052A1 (en) |
| FI (1) | FI69130C (en) |
| PL (1) | PL220500A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4496426A (en) * | 1982-04-06 | 1985-01-29 | Md-Verwaltungesellschaft Nicolaus Gmbh & Co. Kg | Process for the continuous extraction of vegetable-fiber material in two stages |
| AU654997B2 (en) * | 1991-02-06 | 1994-12-01 | Organocell Gesellschaft Fur Zellstoff - Und Umwelttechnik Mbh | Process for the delignification of cellulosic fibre raw materials |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT373303B (en) * | 1981-08-06 | 1984-01-10 | Chemiefaser Lenzing Ag | METHOD FOR THE PRODUCTION OF LOW-LEVEL CELLS |
| AT373932B (en) * | 1981-11-12 | 1984-03-12 | Chemiefaser Lenzing Ag | METHOD FOR RECONSTRUCTING USED DIGESTIVE FLUID FLOWING GEAR, AND PLANTS FOR IMPLEMENTING THIS METHOD |
| DE3339449A1 (en) * | 1983-10-31 | 1985-05-09 | MD Verwaltungsgesellschaft Nicolaus GmbH & Co. KG, 8000 München | METHOD FOR OBTAINING LIGNINE FROM ALKALINE LIGNINE SOLUTIONS |
| US5788812A (en) * | 1985-11-05 | 1998-08-04 | Agar; Richard C. | Method of recovering furfural from organic pulping liquor |
| AT385061B (en) * | 1985-11-29 | 1988-02-10 | Neusiedler Ag | METHOD FOR OBTAINING CELL FABRIC FROM PLANT FIBER MATERIAL |
| ATE245222T1 (en) * | 1997-09-15 | 2003-08-15 | Melville Gordon Brown | METHOD FOR PRODUCING PULP |
| MY137982A (en) * | 1999-08-11 | 2009-04-30 | Startech Internat Group Ltd | Integrated process for treating oil palm biomass wastes |
| DE102009051884A1 (en) * | 2009-11-04 | 2011-05-05 | Blue Globe Energy Gmbh | Processing a biomass comprises separating the biomass into a lignin fraction and (hemi)cellulose fraction, processing the (hemi)cellulose fraction, and converting the lignin fraction into an organo-mineral fertilizer |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE532741C (en) * | 1929-11-02 | 1931-09-08 | Kurt Von Tayenthal Dr Ing | Process for the digestion of vegetable fibers |
| 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 (en) * | 1976-09-30 | 1978-07-27 | Theodor N. Dr. Pointe Claire Quebec Kleinert (Kanada) | Continuous digestion and recovery process for vegetable fiber raw materials for the production of cellulose in organic solvents |
| CA1131415A (en) * | 1978-11-27 | 1982-09-14 | Bau- Und Forschungsgesellschaft Thermoform A.G. | Pulping of lignocellulose with aqueous methanol/ catalyst mixture |
-
1978
- 1978-12-20 DE DE19782855052 patent/DE2855052A1/en not_active Withdrawn
-
1979
- 1979-12-14 BR BR7908189A patent/BR7908189A/en not_active IP Right Cessation
- 1979-12-14 AT AT79105195T patent/ATE1914T1/en not_active IP Right Cessation
- 1979-12-14 DE DE7979105195T patent/DE2964181D1/en not_active Expired
- 1979-12-14 EP EP79105195A patent/EP0012960B1/en not_active Expired
- 1979-12-18 PL PL22050079A patent/PL220500A1/xx unknown
- 1979-12-19 FI FI793985A patent/FI69130C/en not_active IP Right Cessation
- 1979-12-19 CA CA342,248A patent/CA1111694A/en not_active Expired
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4496426A (en) * | 1982-04-06 | 1985-01-29 | Md-Verwaltungesellschaft Nicolaus Gmbh & Co. Kg | Process for the continuous extraction of vegetable-fiber material in two stages |
| AU654997B2 (en) * | 1991-02-06 | 1994-12-01 | Organocell Gesellschaft Fur Zellstoff - Und Umwelttechnik Mbh | Process for the delignification of cellulosic fibre raw materials |
| US5470433A (en) * | 1991-02-06 | 1995-11-28 | Brodersen; Karl-Heinz | Process for the delignification of cellulose fiber raw materials using alcohol and alkali |
Also Published As
| Publication number | Publication date |
|---|---|
| FI69130B (en) | 1985-08-30 |
| EP0012960A1 (en) | 1980-07-09 |
| ATE1914T1 (en) | 1982-12-15 |
| PL220500A1 (en) | 1980-12-01 |
| FI69130C (en) | 1985-12-10 |
| DE2964181D1 (en) | 1983-01-05 |
| DE2855052A1 (en) | 1980-06-26 |
| FI793985A (en) | 1980-06-21 |
| BR7908189A (en) | 1980-07-22 |
| EP0012960B1 (en) | 1982-12-01 |
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