FI91896C - Method of oxygen bleaching - Google Patents
Method of oxygen bleaching Download PDFInfo
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- FI91896C FI91896C FI894949A FI894949A FI91896C FI 91896 C FI91896 C FI 91896C FI 894949 A FI894949 A FI 894949A FI 894949 A FI894949 A FI 894949A FI 91896 C FI91896 C FI 91896C
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- temperature
- zone
- pulp
- delignification zone
- oxygen
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- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
- D21C9/10—Bleaching ; Apparatus therefor
- D21C9/147—Bleaching ; Apparatus therefor with oxygen or its allotropic modifications
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Description
9189691896
Menetelmå happivalkaisun yhteydesså - Sått vid oxygen-blekningMethod in connection with oxygen bleaching - Sått vid oxygen-blekning
Esillå oleva keksinto koskée menetelmåå kuitupitoisen 5 materiaalin happivalkaisun yhteydesså, jossa menetelmåsså massa kulkee ensimmåisen ennalta mååråtysså alemmassa låmpotilassa olevan ligniininpoistovyohykkeen låpi sekå toisen ennalta mååråtysså, korkeammassa kuin ensimmåisesså ligniininpoistovyohykkeen låmpotilassa olevan ligniinin-10 poistovyohykkeen låpi.The present invention relates to a process for the oxygen bleaching of a fibrous material 5, in which the pulp passes through a first predetermined lignin removal zone at a lower temperature in the leaching zone as well as at a higher pre-leaching outlet.
Artikkelissa otsikossa "Oxygen bleaching kinetics at ultra-low consistency", Trappi Journal, joulukuu 1987, C.L. Hsu ja Jeffrey S. Hsieh selostavat kokeita happivalkaisulla, 15 tarkoituksella tutkia låmpotilan vaikutusta viskositeet- tiin. Tulos osoittaa, ettå korkea låmpotila happivalkaisun alkuvaiheessa vaikuttaa negatiivisesti viskositeettiin.In an article entitled "Oxygen bleaching Kinetics at ultra-low consistency", Trappi Journal, December 1987, C.L. Hsu and Jeffrey S. Hsieh describe experiments with oxygen bleaching, 15 to investigate the effect of temperature on viscosity. The result shows that the high temperature in the initial stage of oxygen bleaching has a negative effect on the viscosity.
Happivalkaisussa ei kuitenkaan voida kåyttåå liian alhaista 20 reaktiolåmpotilaa normaalin kappalukualueen saavuttamisek-si. Tåhån tarkoitukseen vaaditaan noin 100°C olevia låmpo-tiloja tai erityistoimenpiteisiin ryhtymistå. Siten on ehdotettu låmpotilan sååtåmistå keskisakean massan happivalkaisun yhteydesså, ks. artikkeli C.E. Courchene ja 25 V.L. Magnotta: "Improvement of medium consistency oxygen bleaching through temperature control", 1984, "Oxygen delignification", ss. 11 - 5. Happiligniininpoisto suori-tettiin laboratoriomallia olevassa vaakasuorassa putki-reaktorissa, johon useissa eri pituuskohdissa syotettiin 30 hoyryå kahden tai useamman vyohykkeen muodostamiseksi, joissa pidettiin eri låmpotiloja, jolloin ensimmåisesså vyohykkeesså oli alin låmpotila. Kokeet osoittivat, ettå låmpotilan sååtåminen alhaisella alkulåmpotilalla vaakasuorassa putkireaktorissa paransi saantoa ja viskositeet-35 tia pitåen viipymisajan ennallaan. Kuvattua låmpotilan sååtoå ei kuitenkaan voidaan menestyksekkååsti soveltaa teollisessa mittakaavassa, koska tarkan låmpotilarajan 2 91896 saavuttaminen kahden tavoitellun låmpotilavyohykkeen vålil-la on vaikeata. Tåmå johtuu mm. siitå, ettå on vaikeata nopeasti ja tehokkaasti sekoittaa hoyryå massaan tasaises-ti, ja myos siitå, ettå vaakasuorassa putkireaktorissa, 5 jossa on ruuvi massan siirtåmistå vårten, on ylåtila, joka ei tåyty massalla, vaan johon muodostuu låmpdtilan sååtoå håiritsevå hoyryfaasi, joka ulottuu pitkin koko vaakasuoran putkireaktorin pituutta.However, in oxygen bleaching, too low a reaction temperature of 20 to achieve a normal kappa number range cannot be used. For this purpose, temperatures of about 100 ° C or special measures are required. Thus, it has been proposed to control the temperature during oxygen bleaching of a medium-thick mass, cf. Article C.E. Courchene and 25 V.L. Magnotta: "Improvement of medium consistency oxygen bleaching through temperature control", 1984, "Oxygen delignification", ss. 11 - 5. Oxygen lignin removal was performed in a laboratory-style horizontal tubular reactor fed 30 vapors at various lengths to form two or more zones with different temperatures, with the first zone having the lowest temperature. Experiments showed that controlling the temperature at a low initial temperature in a horizontal tubular reactor improved the yield and viscosity-35 while keeping the residence time unchanged. However, the described temperature control cannot be successfully applied on an industrial scale because it is difficult to reach the exact temperature limit of 2,91896 between the two target temperature zones. This is due to e.g. because it is difficult to mix the steam with the mass evenly and efficiently evenly, and also because the horizontal tubular reactor 5 with the screw for transferring the mass has an upper space which is not filled with the mass but which forms a temperature-dependent suspension the entire length of the horizontal tubular reactor.
10 Esillå olevan keksinnon tarkoituksena on vålttåå edellå mainitut ongelmat kokonaan, ja aikaansaada happivalkaisun yhteydesså menetelmå, jolla voidaan hyodyntåå happilignii-ninpoiston alkuvaiheen alhaisen låmpotilan ideaa teolli-sesti, ja jolla voidaan aikaansaadan eri ligniininpoisto-15 vyohykkeiden låmpotilojen sååto ja ohjaus, niin ettå lig-niininpoistovyohykkeisiin saadaan vakio alempi ja vastaa-vasti vakio korkeampi låmpotila ilman ligniininpoisto-vyohykkeiden påålle muodostuvaa håiritsevåå hoyryfaasia.The object of the present invention is to avoid the above-mentioned problems completely, and to provide, in connection with oxygen bleaching, a method by which the idea of an initial low-temperature oxygen lignin removal can be utilized industrially and by which the conditions of different lignin removal zones the dewatering zones are given a constant lower and correspondingly a constant higher temperature without the disturbing vapor phase formed on top of the lignin depletion zones.
20 Uutena asiana keksinnosså on se, ettå massa syotetåån ensimmåisen pystyreaktorin låpi, jossa on mainitussa alem-massa låmpotilassa oleva ligniininpoistovyohyke, ja sen jålkeen toiseen pystyreaktoriin, jossa on mainittu toinen korkeammassa låmpotilassa oleva ligniininpoistovyohyke, ja 25 ettå låmpotila ensimmåisesså ligniininpoistovydhykkeesså pidetaån siinå låmpotilassa, jonka valkaisuun tuleva massa on saanut aikaisemmassa, happivalkaisua edeltåvåsså kåsit-telysså, tai ettå sitå tarvittaessa såådetåån såådetyllå hoyryn syottåmisellå ensimmåistå reaktoria edeltåvåsså 30 johdossa olevaan sekoittimeen, ja ettå toisen ligniinin- poistovydhykkeen låmpotilaa såådetåån syottåmållå såådetys-ti hoyryå reaktoreiden vålisesså johdossa olevaan sekoittimeen .20 What is new in the present invention is that the pulp is fed through a first vertical reactor having a lignin removal zone at said low temperature temperature, and then to a second vertical reactor having a second high temperature lignin removal zone at a higher temperature. from the bleaching of pulp has been received earlier, oxygen bleaching edeltåvåsså chaise-telysså, and working or, if necessary, the SITA såådetåån såådetyllå Vapor syottåmisellå ensimmåistå reactor edeltåvåsså line mixer 30, and the second and working lignin poistovydhykkeen the outside temperature såådetåån syottåmållå såådetys t-vapor-vålisesså reactors in the line mixer.
35 Keksintoå selitetåån seuraavassa låhemmin piirustukseen viitaten, jossa II.35 The invention will now be described in more detail with reference to the drawing, in which II.
3 918963,91896
Kuvio 1 esittåå kaaviollisesti valkaisulaitoksen keksin-ηόη mukaisen menetelmån toteuttamiseksi; jaFig. 1 schematically shows a bleaching plant for carrying out the method according to the invention; and
Kuvio 2 on kåyråsto, joka esittåå kappaluvun ja vis-5 kositeetin vålisen yhteyden.Fig. 2 is a graph showing the relationship between the number of pieces and the vis-5 cosity.
Kuviossa 1 esitetty valkaisulaitos on tarkoitettu happival-kaisuun kahdessa eri vaiheessa, ja siihen sisåltyy tålloin ensimmåinen reaktori 1 ja toinen reaktori 2. Massa syote-10 tåån varastosåiliostå 3 ensimmåiselle reaktorille 1 varas-tosåilion 3 ulostulossa olevan pumpun 5 avulla johdon 4 ja sekoittimen 6 kautta, jolloin sekoitin on laite kåsittely-aineiden syottåmiseksi johtoon 4. Sekoitin 6 voi kåsittåå nesteytyslaitteen mm. erilaisten lisåaineiden nopeata ja 15 tasaista massaan sekoittamista vårten. Sekoitin voi edulli-sesti muodostua "Kamyr MC-mixer"-laitteesta. Valkaistava massa on siis keskisakeaa, ts. noin 6 - 15 %.The bleaching plant shown in Fig. 1 is intended for oxygen bleaching in two different stages, and then includes a first reactor 1 and a second reactor 2. The pulp is fed from the storage tank 3 to the first reactor 1 by means of a pump 5 at the outlet of the storage tank 3 via line 4 and mixer 6. , in which case the mixer is a device for feeding treatment substances into the line 4. The mixer 6 can comprise a liquefaction device e.g. for rapid and uniform mixing of various additives into the pulp. The mixer can preferably consist of a "Kamyr MC-mixer". The mass to be bleached is thus medium thick, i.e. about 6-15%.
Reaktorit 1, 2 liittyvåt toisiinsa johdolla 7, joka sisål-20 tåå sekoittimen 8, joka on samaa lajia kuin edellå kuvattu. Toisesta reaktorista 2 happiligniinin poistettu massa syo-tetåån puhallustankkiin 9 johdon 10 kautta.The reactors 1, 2 are connected to each other by a line 7 containing 20 agitators 8 of the same type as described above. The mass of oxygen lignin removed from the second reactor 2 is fed to the blow tank 9 via line 10.
Varastosåilidn 3 ulostulossa johdon 11 kautta lisåtåån 25 selluloosan suoja-ainetta, esim. MgS04. Ensimmåiseen suuri-tehoiseen sekoittimeen 6 syotetåån johdon 12 kautta emåk-sistå ainetta, kuten NaOH, tai hapetettua valkolipeåå, ja johdon 13 kautta happikaasua. Lisåksi sekoittimeen 6 on liitetty johto 14 korkeapainehoyryå vårten. Toiseen sekoit-30 timeen 15 tulee johtoja 15, 16, jotka on liitetty happi- kaasun ja vastaavasti korkeapainehoyryn syottåmistå vårten. Voidaan my5s jårjeståå johto 17 emåksisen aineen lisååmi-seksi ensimmåisesså vaiheessa happiligniinin poistettuun massaan.At the outlet of the storage tank 3, 25 cellulose preservatives, e.g. MgSO 4, are added via line 11. A basic substance such as NaOH or oxidized white liquor is fed to the first high-efficiency mixer 6 via line 12 and oxygen gas via line 13. In addition, a line 14 for high-pressure steam is connected to the mixer 6. The second mixer 15 is provided with lines 15, 16 connected for the supply of oxygen gas and high pressure steam, respectively. It is also possible to arrange a line 17 for the addition of a basic substance in the first step to the removed oxygen-lignin mass.
3535
Valkaisulaitos kåsittåå lisåksi sopivia mittaus- ja sååto-elimiå (ei esitetty) molempien reaktoreiden låmpotilan 91896 4 mittaaraiseksi sekå hoyryn syoton sååtåmiseksi sekoittimiin, niin ettå reaktoreissa yllåpidetåån oikeat eri låmpotilat esillå olevan keksinnon mukaisesti.The bleaching plant further comprises suitable measuring and charging means (not shown) for measuring the temperature of both reactors 91896 4 and for controlling the feed of steam to the mixers, so that the correct different temperatures are maintained in the reactors in accordance with the present invention.
5 Ensimmåinen reaktori 1 sisåltåå tålloin ensimmåisen ligniininpoistovyohykkeen, jossa on alueella 70 - 90°C oleva alempi låmpotila, edullisesti 75 - 85°C, kun taas toinen reaktori sisåltåå toisen ligniininpoistovyohykkeen, jossa on korkeampi låmpotila alueella 90 - 125°C, edullisesti 10 95 - 110°C. Ilmaisut "alempi" ja "korkeampi" viittaavat siis ligniininpoistovyohykkeiden keskinåisiin låmpotilasuh-teisiin. Ligniininpoistovyohykkeiden vålisen låmpotilaeron tulee olla noin 20 - 40°C, edullisesti noin 30°C.The first reactor 1 then comprises a first lignin removal zone with a lower temperature in the range of 70 to 90 ° C, preferably 75 to 85 ° C, while the second reactor contains a second lignin removal zone with a higher temperature in the range of 90 to 125 ° C. - 110 ° C. The terms "lower" and "higher" thus refer to the relative temperature ratios of the lignin removal zones. The temperature difference between the lignin removal zones should be about 20 to 40 ° C, preferably about 30 ° C.
15 Sellaisissa tapauksissa, joissa valkaisuun tuleva massa on riittåvåsså låmpotilassa, jonka se on saanut edeltåvåsså happivalkaisun kåsittelysså, ja joka vastaa ilmaisua "alempi låmpotila", ts. alueella 70 - 90°C, ei siis normaalisti tarvitse syottåå hoyryå lisåksi sekoittimeen 6, edellyttå-20 en, ettå låmpotila on vakio tai pååasiassa vakio.15 In cases where the pulp to be bleached is at a sufficient temperature to be obtained in the previous oxygen bleaching treatment and which corresponds to the term "lower temperature", i.e. in the range 70-90 ° C, it is therefore not normally necessary to feed steam in addition to the mixer 6, 20 I do not state that the temperature is constant or mainly constant.
Seuraava esimerkki valaisee keksintoå.The following example illustrates the invention.
Esimerkki 25Example 25
Happiligniininpoisto kahdessa vaiheessa suoritettiin kuvion 1 mukaisessa valkaisulaitoksessa. Låmpotilaa muutettiin kolmessa eri koesarjassa niin, ettå ensimmåisesså kokeessa ensimmåisen vaiheen (ensimmåisen ligniininpoistovyohykkeen) 30 låmpotila oli 75°C, toisessa kokeessa 85°C, ja kolmannessa kokeessa 105°C, kun taas låmpotila toisessa vaiheessa (toisessa ligniininpoistovyohykkeesså) oli 105°C kaikissa kolmessa kokeessa. Happivalkaisuun tuleva havupuuta olevan massa kappaluku oli 28,7, viskositeetti 1141 dm3/kg, ja 35 sakeus 10 %. Alkupaine (ylipaine) oli molemmissa ligniinin-poistovyohykkeisså, ts. vaiheessa 1 ja 2, noin 0,5 MPa, ja kaikissa kokeissa kåsittelyaika vaiheessa 1 oli 15 minuut-Oxygen lignin removal in two steps was performed in the bleaching plant of Figure 1. The temperature was changed in three different series of experiments so that in the first experiment the temperature of the first stage (first lignin removal zone) was 75 ° C, in the second experiment 85 ° C, and in the third experiment 105 ° C, while the temperature in the second stage (second lignin removal zone) was 105 ° C. in three experiments. The pulp number of softwood entering oxygen bleaching was 28.7, the viscosity was 1141 dm3 / kg, and the consistency was 10%. The initial pressure (gauge pressure) in both lignin removal zones, i.e., in steps 1 and 2, was about 0.5 MPa, and in all experiments the treatment time in step 1 was 15 minutes.
IIII
5 91896 tia ja 45 minuuttia vaiheessa 2. Pumpulle 5 tuotiin 5 kg MgS04 kuivaa massatonnia kohti johdolla 11. Jokainen koe toistettiin niin, ettå ainoana erona ensimmåisesså tapauk-sessa kåytettiin 20 kg NaOH kuivaa massatonnia kohti, 5 toisessa tapauksessa 25 kg NaOH ja kolmannessa tapauksessa 30 kg NaOH kuivaa massatonnia kohti, paitsi ensimmåisesså kokeessa, jossa kåytettiin toisessa tapauksessa 30 kg NaOH ja kolmannessa tapauksessa 35 kg NaOH kuivaa massatonnia kohti (25 ja vastaavasti 30 sijasta). Yleisesti påtee, ettå 10 suurempi emåsannostus tuottaa pienemmån kappaluvun ja vis-kositeetin muutoin samoissa olosuhteissa. Lisåksi tehtiin neljås koe, jossa happiligniininpoisto suoritettiin kahdes-sa vaiheessa 105°C låmpotilassa 60 minuutin ajan, emåsan-nostuksen ollessa 30 kg NaOH kuivaa massatonnia kohti.5 91896 t and 45 minutes in step 2. Pump 5 was supplied with 5 kg MgSO 4 per tonne of dry pulp on line 11. Each experiment was repeated with the only difference in the first case being 20 kg NaOH per tonne dry pulp, in the second case 25 kg NaOH and in the third case 30 kg NaOH per tonne of dry pulp, except in the first experiment, which used 30 kg of NaOH in the second case and 35 kg of NaOH per tonne of dry pulp in the third case (instead of 25 and 30, respectively). It is generally accepted that a higher maternal dosage produces a lower kappa number and viscosity under otherwise the same conditions. In addition, a fourth experiment was performed in which oxygen lignin removal was performed in two steps at 105 ° C for 60 minutes with a base addition of 30 kg of NaOH per ton of dry pulp.
15 Tulokset kåyvåt ilmi kuviosta 2. Oikealla puolella merkityt arvot siis liittyvåt pienimpåån emåsannostukseen (20 kg) mainitussa kolmessa kokeessa, kun taas vasemmalla puolella olevat arvot liittyvåt suurimpaan emåsannostukseen (35, 30, 30 kg).15 The results are shown in Figure 2. Thus, the values marked on the right are related to the lowest female dose (20 kg) in the three experiments, while the values on the left are related to the highest female dose (35, 30, 30 kg).
2020
Tulokset osoittavat, ettå happiligniininpoiston alkuvaiheen korkea låmpotila vaikuttaa negatiivisesti viskositeettiin, ja ettå alempi låmpotila alkuvaiheessa tuottaa happilig-niininpoistetun massan, jolla on parempi viskositeetti ja 25 kappaluku, joka on normaalin ja toivotun alueen puitteissa. Kåyråstostå ilmenee lisåksi, ettå alempi låmpotila happiligniininpoiston alkuvaiheessa tuottaa 15 - 30 yksikkoå suuremman viskositeetin samalla kappaluvulla mitattuna, verrattuna happiligniininpoistoon ainoastaan yhdesså vai-30 heessa ja korkeassa låmpotilassa. Tåtå vaikutusta voidaan hyodyntåå joko sellaisen massan valmistamiseksi, jolla on paremmat lujuusominaisuudet, tai happiligniinin poistetun massan kappaluvun alentamiseen 1-2 yksikollå viskositeetin pysyesså ennallaan. Viimeksi mainittu menettely on 35 mielenkiintoinen ympåristonåkokohdasta, koska se merkitsee kloorin kulutuksen pienenemistå sitå seuraavassa valkaisu- 91896 6 laitoksessa ja siten vastaavaa orgaanisten klooriyhdistei-den pååstojen pienenemistå.The results show that the high temperature at the initial stage of deoxygenation has a negative effect on the viscosity, and that the lower temperature at the initial stage produces a deoxygenated pulp with a better viscosity and a number of pieces within the normal and desired range. In addition, the graph shows that a lower temperature at the initial stage of oxygen lignin removal produces a viscosity of 15 to 30 units higher measured at the same kappa number, compared to oxygen lignin removal in only one step and at a high temperature. This effect can be exploited either to produce a pulp with better strength properties or to reduce the number of pieces of oxygen lignin removed by 1-2 units while maintaining the viscosity. The latter procedure is interesting from an environmental point of view, since it implies a reduction in chlorine consumption in the subsequent bleaching plant and thus a corresponding reduction in emissions of organochlorine compounds.
Koska ligniininpoistovyohykkeet ovat etåisyydellå toisis-5 taan, nimittåin kumpikin reaktorissaan 1, 2, niin lig- niininpoistovyohykkeiden påålle tai niiden våliin ei muo-dostu mitåån håiritsevåå hoyryfaasia, ja aikaansaadaan eri ligniininpoistovyohykkeiden låmpotilojen tehokas sååto ja ohjaus, koska hoyryå syotetåån sekoittimiin 6, 8 ennen 10 reaktoreita 1, 2, jolloin sekoittimet tuottavat tasaisen hoyryn sekoittumisen massaan, niin ettå ongelmitta voidaan yllåpitåa vakio, alempi låmpotila ensimmåisesså reaktoris-sa, ja samoin yllåpitåa ongelmitta vakio, korkeampi låmpotila toisessa reaktorissa.Since the lignin removal zones are spaced apart from each other, namely in each of the reactors 1, 2, no interfering effluent phase is formed on or between the lignin removal zones, and different lignin removal phases are obtained. 10 reactors 1, 2, whereby the mixers produce a uniform mixing of steam into the pulp, so that a constant, lower temperature in the first reactor can be maintained without problems, and a constant, higher temperature in the second reactor can also be maintained without problems.
1515
IIII
Claims (3)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE8803705A SE467582B (en) | 1988-10-18 | 1988-10-18 | OXYGEN WHITING |
SE8803705 | 1988-10-18 |
Publications (3)
Publication Number | Publication Date |
---|---|
FI894949A0 FI894949A0 (en) | 1989-10-18 |
FI91896B FI91896B (en) | 1994-05-13 |
FI91896C true FI91896C (en) | 1994-08-25 |
Family
ID=20373661
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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FI894949A FI91896C (en) | 1988-10-18 | 1989-10-18 | Method of oxygen bleaching |
Country Status (4)
Country | Link |
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JP (1) | JPH02145883A (en) |
CA (1) | CA1337843C (en) |
FI (1) | FI91896C (en) |
SE (1) | SE467582B (en) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
SE510740C2 (en) * | 1996-11-26 | 1999-06-21 | Sunds Defibrator Ind Ab | Oxygen delignification control |
SE522593C2 (en) * | 1999-07-06 | 2004-02-24 | Kvaerner Pulping Tech | Oxygen gas delignification system and method of pulp of lignocellulosic material |
RU2479619C2 (en) * | 2009-11-17 | 2013-04-20 | Феликс Фердинандович Аухадеев | Pulsation apparatus for delignification of cellulose-containing plant material and method for operation thereof |
-
1988
- 1988-10-18 SE SE8803705A patent/SE467582B/en not_active IP Right Cessation
-
1989
- 1989-09-28 CA CA000614212A patent/CA1337843C/en not_active Expired - Lifetime
- 1989-10-18 JP JP1269259A patent/JPH02145883A/en active Pending
- 1989-10-18 FI FI894949A patent/FI91896C/en active IP Right Grant
Also Published As
Publication number | Publication date |
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SE467582B (en) | 1992-08-10 |
FI91896B (en) | 1994-05-13 |
SE8803705L (en) | 1990-04-19 |
CA1337843C (en) | 1996-01-02 |
SE8803705D0 (en) | 1988-10-18 |
FI894949A0 (en) | 1989-10-18 |
JPH02145883A (en) | 1990-06-05 |
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