NO176406B - Method of Bleaching Mass - Google Patents
Method of Bleaching Mass Download PDFInfo
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- NO176406B NO176406B NO893714A NO893714A NO176406B NO 176406 B NO176406 B NO 176406B NO 893714 A NO893714 A NO 893714A NO 893714 A NO893714 A NO 893714A NO 176406 B NO176406 B NO 176406B
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- Prior art keywords
- bleaching
- pulp
- oxidation
- treatment
- enzyme
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- 238000004061 bleaching Methods 0.000 title claims abstract description 53
- 238000000034 method Methods 0.000 title claims abstract description 27
- 108090000790 Enzymes Proteins 0.000 claims abstract description 45
- 102000004190 Enzymes Human genes 0.000 claims abstract description 45
- OSVXSBDYLRYLIG-UHFFFAOYSA-N dioxidochlorine(.) Chemical compound O=Cl=O OSVXSBDYLRYLIG-UHFFFAOYSA-N 0.000 claims abstract description 32
- 230000003647 oxidation Effects 0.000 claims abstract description 29
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 29
- 239000000126 substance Substances 0.000 claims abstract description 29
- 239000004155 Chlorine dioxide Substances 0.000 claims abstract description 16
- 239000003513 alkali Substances 0.000 claims abstract description 16
- 235000019398 chlorine dioxide Nutrition 0.000 claims abstract description 16
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims abstract description 11
- 239000000460 chlorine Substances 0.000 claims abstract description 11
- 229910052801 chlorine Inorganic materials 0.000 claims abstract description 11
- 229940088598 enzyme Drugs 0.000 claims description 43
- 239000000203 mixture Substances 0.000 claims description 14
- KZBUYRJDOAKODT-UHFFFAOYSA-N Chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 claims description 9
- 229940059442 hemicellulase Drugs 0.000 claims description 5
- 108010002430 hemicellulase Proteins 0.000 claims description 5
- 238000009896 oxidative bleaching Methods 0.000 claims description 5
- 108010059892 Cellulase Proteins 0.000 claims description 3
- 108090000371 Esterases Proteins 0.000 claims description 3
- 108010059820 Polygalacturonase Proteins 0.000 claims description 3
- 229940106157 cellulase Drugs 0.000 claims description 3
- 108010093305 exopolygalacturonase Proteins 0.000 claims description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 abstract description 11
- 239000001301 oxygen Substances 0.000 abstract description 11
- 229910052760 oxygen Inorganic materials 0.000 abstract description 11
- VGVRPFIJEJYOFN-UHFFFAOYSA-N 2,3,4,6-tetrachlorophenol Chemical class OC1=C(Cl)C=C(Cl)C(Cl)=C1Cl VGVRPFIJEJYOFN-UHFFFAOYSA-N 0.000 abstract description 3
- 239000007844 bleaching agent Substances 0.000 abstract description 3
- 238000002474 experimental method Methods 0.000 description 29
- 238000005406 washing Methods 0.000 description 11
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 6
- 229920005610 lignin Polymers 0.000 description 5
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 4
- 238000000354 decomposition reaction Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 239000007788 liquid Substances 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 150000004045 organic chlorine compounds Chemical class 0.000 description 3
- 229910021653 sulphate ion Inorganic materials 0.000 description 3
- 231100000331 toxic Toxicity 0.000 description 3
- 230000002588 toxic effect Effects 0.000 description 3
- 239000003643 water by type Substances 0.000 description 3
- 101710121765 Endo-1,4-beta-xylanase Proteins 0.000 description 2
- 229920002488 Hemicellulose Polymers 0.000 description 2
- 241000187747 Streptomyces Species 0.000 description 2
- 238000003912 environmental pollution Methods 0.000 description 2
- 238000000855 fermentation Methods 0.000 description 2
- 230000004151 fermentation Effects 0.000 description 2
- 231100000989 no adverse effect Toxicity 0.000 description 2
- 238000000746 purification Methods 0.000 description 2
- 239000002351 wastewater Substances 0.000 description 2
- 235000018185 Betula X alpestris Nutrition 0.000 description 1
- 235000018212 Betula X uliginosa Nutrition 0.000 description 1
- ZKQDCIXGCQPQNV-UHFFFAOYSA-N Calcium hypochlorite Chemical class [Ca+2].Cl[O-].Cl[O-] ZKQDCIXGCQPQNV-UHFFFAOYSA-N 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- 229920002678 cellulose Polymers 0.000 description 1
- 239000001913 cellulose Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000005660 chlorination reaction Methods 0.000 description 1
- 150000001805 chlorine compounds Chemical class 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000010411 cooking Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 238000009533 lab test Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011122 softwood Substances 0.000 description 1
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
- 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
- D21C9/1057—Multistage, with compounds cited in more than one sub-group D21C9/10, D21C9/12, D21C9/16
-
- 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
- D21C5/00—Other processes for obtaining cellulose, e.g. cooking cotton linters ; Processes characterised by the choice of cellulose-containing starting materials
- D21C5/005—Treatment of cellulose-containing material with microorganisms or enzymes
-
- 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
- D21C9/12—Bleaching ; Apparatus therefor with halogens or halogen-containing compounds
- D21C9/14—Bleaching ; Apparatus therefor with halogens or halogen-containing compounds with ClO2 or chlorites
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Wood Science & Technology (AREA)
- Chemical & Material Sciences (AREA)
- Biochemistry (AREA)
- Microbiology (AREA)
- Paper (AREA)
- Polysaccharides And Polysaccharide Derivatives (AREA)
- Noodles (AREA)
- Cereal-Derived Products (AREA)
- Table Devices Or Equipment (AREA)
- Silver Salt Photography Or Processing Solution Therefor (AREA)
Abstract
Description
Foreliggende oppfinnelse angår en fremgangsmåte for bleking av masse der det benyttes et oksyderende blekekjemikalium inneholdende klor. The present invention relates to a method for bleaching pulp in which an oxidizing bleaching chemical containing chlorine is used.
Spesielt masse oppnådd fra en sulfatkokeprosess har en brun farve, noe som hovedsakelig skyldes lignin som er tilbake i massen. Lignin fjernes fra massen ved bleking, en prosess som består av flere trinn. Under denne prosess blir massen behandlet alternativt med oksyderende, 1ignin-nedbrytende kjemikalier og kjemikalier som oppløser nedbrytningsproduktene. Oksydasjonsmidler som hyppig benyttes er oksygen og klorholdige kjemikalier som ren klorgass, klordioksyd og natrium- og kalsiumhypokloriter, mens alkalioppløsninger benyttes for å fjerne nedbrytningsproduktene. In particular, pulp obtained from a sulphate cooking process has a brown colour, which is mainly due to lignin remaining in the pulp. Lignin is removed from the pulp by bleaching, a process that consists of several steps. During this process, the mass is treated alternatively with oxidizing, ignin-degrading chemicals and chemicals that dissolve the decomposition products. Oxidizing agents that are frequently used are oxygen and chlorine-containing chemicals such as pure chlorine gas, chlorine dioxide and sodium and calcium hypochlorites, while alkali solutions are used to remove the decomposition products.
I de reaksjoner som inntrer ved bleking ved bruk av klorholdige kjemikalier blir lignin omdannet til organiske klorforbindelser som oppløses i blekeavløpet. Blekeavløpet er et problem med henblikk på miljøvern på grunn av den toksiske natur av klorfenoler og andre mulige organiske klorforbindelser i væskene. I tillegg når det kjemiske oksygenbehov i blekeavløp skadelige nivåer. Da forholdsreg-ler som er tatt sikte på å redusere omgivelses forurensnings-belastning på grunn av sulfatmassefremstilling til nu har vært konsentrert på andre deler av prosessen og ikke blekingen, har den relative betydning av blekingen som en forurensningsfaktor fått økende betydning. In the reactions that occur during bleaching using chlorine-containing chemicals, lignin is converted into organic chlorine compounds that dissolve in the bleaching effluent. The bleach effluent is a problem for environmental protection because of the toxic nature of chlorophenols and other possible organic chlorine compounds in the liquids. In addition, the chemical oxygen demand in bleach effluent reaches harmful levels. As precautions aimed at reducing environmental pollution due to sulphate pulp production have so far been concentrated on other parts of the process and not bleaching, the relative importance of bleaching as a pollution factor has gained increasing importance.
Blekeavløp som forårsaker de verste omgivelsesforurensninger fremstilles under vaskingen som følger den første klorering og den første alkalibehandling i blekeprosessen. For å redusere utslippet av avløp er det benyttet forskjellige metoder, for eksempel den såkalte utvidede fermentering, bruk av klordioksyd som oksyderende blekekjemikalium, oksygenblek-ing og biologisk rensing av den brukte blekevæske. Imidler-tid er de resultater som til nu har vært oppnådd ved disse metoder ikke fullt ut tilfredsstillende. Selv om mengden klorfenoler og andre toksiske klorforbindelser i blekeavløpet vesentlig er redusert ved å benytte klordioksyd- og oksy-genbleking, har det ikke vært mulig å oppnå en tilstrekkelig reduksjon i det kjemiske oksygenbehov for avløpene. Derfor har de angitte metoder krevet anvendelse av effektiv biologisk rensing. Bleaching effluents that cause the worst environmental pollution are produced during the washing that follows the first chlorination and the first alkali treatment in the bleaching process. In order to reduce the discharge of waste water, various methods have been used, for example the so-called extended fermentation, the use of chlorine dioxide as an oxidizing bleaching chemical, oxygen bleaching and biological purification of the used bleaching liquid. However, the results that have been achieved so far with these methods are not fully satisfactory. Although the amount of chlorophenols and other toxic chlorine compounds in the bleaching effluent has been significantly reduced by using chlorine dioxide and oxygen bleaching, it has not been possible to achieve a sufficient reduction in the chemical oxygen demand for the effluents. Therefore, the specified methods have required the application of effective biological purification.
Gjenstand for foreliggende oppfinnelse er å tilveiebringe en fremgangsmåte som muliggjør at det toksiske innholdet og det kjemiske oksygenbehov for blekeavløpet kan reduseres for derved å redusere behovet for rensing av væsken. The object of the present invention is to provide a method which enables the toxic content and the chemical oxygen demand for the bleaching effluent to be reduced, thereby reducing the need for cleaning the liquid.
Oppfinnelsen angår således en fremgangsmåte av den inn-ledningsvis nevnte art og denne fremgangsmåte karakteriseres ved at det i oksydasjonstrinnet benyttes et kjemikalium med et klordioksydinnhold på minst 70 %, at massen underkastes enzymbehandling før oksydasjon og at massen efter oksydasjon og enzymbehandlingen behandles med et alkali. The invention thus relates to a method of the kind mentioned at the outset and this method is characterized by the fact that a chemical with a chlorine dioxide content of at least 70% is used in the oxidation step, that the mass is subjected to enzyme treatment before oxidation and that the mass is treated with an alkali after oxidation and the enzyme treatment.
Det er ved tidligere undersøkelser observert at ved å benytte enzymer er det mulig å separere lignin og/eller hemicellulose fra cellulose og derved gi massen en mere svamplignende kvalitet. Dette rettferdiggjør den antagelse at hvis massen som oppnås fra fermenteringsprosessen først underkastes en enzymbehandling er det mulig å redusere mengden av kjemikalier som benyttes i det neste bleketrinn. I henhold til oppfinnelsen er det nu observert at enzymbehandlingen vesentlig reduserer mengden organiske klorforbindelser i blekeavløpet mens man samtidig reduserer det kjemiske oksygenbehov, spesielt når minst 50$ og fortrinnsvis minst 70$ av blekekjemikaliene som benyttes i oksydasjonstrinnet, består av klordioksyd. Hvis ren klorgass benyttes har enzymbehandlingen en vesentlig svakere virkning på kvaliteten av blekeavløpet. It has been observed in previous investigations that by using enzymes it is possible to separate lignin and/or hemicellulose from cellulose and thereby give the pulp a more sponge-like quality. This justifies the assumption that if the mass obtained from the fermentation process is first subjected to an enzyme treatment, it is possible to reduce the amount of chemicals used in the next bleaching step. According to the invention, it has now been observed that the enzyme treatment significantly reduces the amount of organic chlorine compounds in the bleaching effluent while at the same time reducing the chemical oxygen demand, especially when at least 50% and preferably at least 70% of the bleaching chemicals used in the oxidation step consist of chlorine dioxide. If pure chlorine gas is used, the enzyme treatment has a significantly weaker effect on the quality of the bleaching effluent.
I henhold til oppfinnelsen blir massen underkastet enzymbehandling og vasking før det første oksydasjonstrinn. Enzymet bryter ned hemicellulose og/eller lignin inneholdt i massen og gjør massen mere svampaktig og øker derved virkningen av kjemikaliene i efterfølgende oksydasjons- og alkalibehandlingstrinn. Ved vasking av massen efter enzymbehandlingen blir nedbrytningsproduktene fjernet og kan brennes slik at de ikke bidrar til avløpsutslipp i det hele tatt. According to the invention, the pulp is subjected to enzyme treatment and washing before the first oxidation step. The enzyme breaks down the hemicellulose and/or lignin contained in the pulp and makes the pulp more spongy and thereby increases the effect of the chemicals in subsequent oxidation and alkali treatment steps. When washing the mass after the enzyme treatment, the decomposition products are removed and can be burned so that they do not contribute to waste water emissions at all.
Bortsett fra enzymbehandlingen kan blekingen av massen ved oppfinnelsens fremgangsmåte gjennomføres på konvensjonell måte ved å benytte alternerende oksydasjons- og alkalibehand-lingsfaser og vasking av massen efter hver av disse faser for å fjerne blekekjemikaliene og nedbrytningsproduktene. Apart from the enzyme treatment, the bleaching of the pulp by the method of the invention can be carried out in a conventional manner by using alternating oxidation and alkali treatment phases and washing the pulp after each of these phases to remove the bleaching chemicals and decomposition products.
Enzymbehandlingen som beskrevet ved oppfinnelsen gjennomføres fortrinnsvis innen et temperaturområde av 10 til 90° C, fortrinnsvis 40 til 75°C og med pH verdier innen området 3 til 10 og fortrinnsvis 4 til 9. Det benyttede enzym kan være hemicellulase, cellulase, pektinase, esterase eller en blanding derav. The enzyme treatment as described in the invention is preferably carried out within a temperature range of 10 to 90°C, preferably 40 to 75°C and with pH values within the range 3 to 10 and preferably 4 to 9. The enzyme used can be hemicellulase, cellulase, pectinase, esterase or a mixture thereof.
Oppfinnelsens fremgangsmåte anvender et enzym for å redusere klorinnholdet i blekeavløpet som dannes ved bleking av masse når det benyttes et oksyderende blekekjemikalium inneholdende minst 50% klordioksyd. Enzymet er fortrinnsvis hemicellulase, cellulase, pektinase, esterase eller en blanding derav. Enzymet benyttes i det vesentlige på den måte som er beskrevet ovenfor i blekeprosedyren. The method of the invention uses an enzyme to reduce the chlorine content in the bleaching effluent which is formed by bleaching pulp when an oxidizing bleaching chemical containing at least 50% chlorine dioxide is used. The enzyme is preferably hemicellulase, cellulase, pectinase, esterase or a mixture thereof. The enzyme is essentially used in the manner described above in the bleaching procedure.
Oppfinnelsen skal beskrives i større detalj nedenfor ved hjelp av eksempler på utførelsesformer, basert på labora-torieforsøk . The invention will be described in greater detail below using examples of embodiments, based on laboratory tests.
Eksempel 1 Example 1
En fortynnet enzymblanding (streptomyces hemicellulase) ble satt til 220 g tørrstoff fra bjerkesulfatmasse (med et tørrstoffinnhold på 30$) slik at det ble oppnådd en blanding med en konsistens på 10% og xylanaseaktivitet på 5 U/g tørrmasse. Temperaturen ved enzymbehandlingen var 55°C, behandlingens varighet var 2 timer og pH verdien var 8,0. A diluted enzyme mixture (streptomyces hemicellulase) was added to 220 g of dry matter from birch sulphate pulp (with a dry matter content of 30$) so that a mixture with a consistency of 10% and xylanase activity of 5 U/g dry matter was obtained. The temperature during the enzyme treatment was 55°C, the duration of the treatment was 2 hours and the pH value was 8.0.
Efter enzymbehandlingen ble massen underkastet en oksyderende blekebehandling ved bruk av en blanding inneholdende 90% klordioksyd og 10$ klorgass, i en dosering tilsvarende 1,4 x post-enzymbehandlings X, -tallet for massen. Behandlingstemperaturen var 55°C og behandlingens varighet var 45 minutter. Efter oksydasjonsfasen ble massen vasket i en Biichner-trakt med 20 ganger sin mengde av vann. After the enzyme treatment, the pulp was subjected to an oxidizing bleaching treatment using a mixture containing 90% chlorine dioxide and 10% chlorine gas, in a dosage corresponding to 1.4 x the post-enzyme treatment X, number for the pulp. The treatment temperature was 55°C and the treatment duration was 45 minutes. After the oxidation phase, the mass was washed in a Biichner funnel with 20 times its amount of water.
Derefter ble massen underkastet en alkalibehandling ved bruk av 5% natriumhydroksydoppløsning i en dosering på 0,8 x Konsistensen for blandingen var 10$, behandlingstemperaturen 60"C og behandlingsvarigheten 90 minutter. Efter alkali-behandlingen ble massen vasket på samme måte som efter oksydasjonsfasen. The mass was then subjected to an alkali treatment using a 5% sodium hydroxide solution in a dosage of 0.8 x The consistency of the mixture was 10$, the treatment temperature 60°C and the treatment duration 90 minutes. After the alkali treatment, the mass was washed in the same way as after the oxidation phase.
Efter dette ble blekingen fortsatt ved å gjenta oksydasjon-og alkalifåsene og så nok en gang oksydasjonsfasen og vasking av massen mellom disse faser som beskrevet ovenfor. For de kombinerte vaskevann bestemte man mengden organisk bundet klor (A0X) og det kjemiske oksygenbehov (COD), de oppnådde verdier er gitt i tabell 1 (forsøk 3) nedenfor. After this, the bleaching was continued by repeating the oxidation and alkali phases and then once again the oxidation phase and washing of the pulp between these phases as described above. For the combined washing waters, the amount of organically bound chlorine (A0X) and the chemical oxygen demand (COD) were determined, the values obtained are given in table 1 (experiment 3) below.
I tillegg til det ovenfor angitte forsøk (forsøk 3) som illustrerer oppfinnelsen ble det gjennomført to referanse-forsøk (forsøkene 1 og 2) og et ytterligere forsøk (forsøk 4), og Å0X- og COD-verdiene for de kombinerte vaskevann oppnådd fra forskjellige trinn av forsøkene er også angitt i tabell 1. Forsøkene ble gjennomført som følger. In addition to the above experiment (experiment 3) which illustrates the invention, two reference experiments (experiments 1 and 2) and a further experiment (experiment 4) were carried out, and the Å0X and COD values for the combined washing waters obtained from different steps of the experiments are also indicated in table 1. The experiments were carried out as follows.
Forsøk 2 (referanse): Det ble ikke benyttet noen enzymbehandling. Doseringen av blekekjemikaliene i de forskjellige trinn av behandlingen under blekingen var to x , den vanligvis benyttede dosering. I andre henseende var forsøket analogt det som var beskrevet ovenfor, altså forsøk 3. Experiment 2 (reference): No enzyme treatment was used. The dosage of the bleaching chemicals in the different stages of the treatment during the bleaching was twice the dosage usually used. In other respects, the experiment was analogous to that described above, i.e. experiment 3.
Forsøk 1 (referanse): Det ble ikke benyttet noen enzymbehandling. Det benyttede blekekjemikalium i oksydasjonstrinnene var ren klorgass i en dosering på 2 x <2>fC .1 andre henseende var forsøket analogt det ovenfor beskrevne, (forsøk 3). Experiment 1 (reference): No enzyme treatment was used. The bleaching chemical used in the oxidation steps was pure chlorine gas in a dosage of 2 x <2>fC. In other respects, the experiment was analogous to that described above (experiment 3).
Forsøk 4: Massen ble behandlet med et enzym og bleket som beskrevet ovenfor (forsøk 3). I tillegg ble massen vasket efter enzymbehandlingen før den første oksydasjonsbehandling med en blanding av klordioksyd og klorogass. Oppfinnelsen omfatter en fremgangsmåte som benytter prinsippet ifølge dette forsøk. Trial 4: The pulp was treated with an enzyme and bleached as described above (trial 3). In addition, the mass was washed after the enzyme treatment before the first oxidation treatment with a mixture of chlorine dioxide and chlorine gas. The invention includes a method that uses the principle according to this experiment.
Resultatene antyder at, sammenlignet med tilsvarende bleking uten enzymbehandling, enzymbehandlingen kombinert med klordioksydbleking som tilveiebragt ifølge oppfinnelsen, vesentlig reduserer forurensningsbelastningen som forårsakes av blekeavløp målt uttrykt ved AOX- og COD-verdiene. Sammenlignet med den vanligvis benyttede klorbleking er forbedringen som oppnås ennu mere distinkt. Videre er det verdt å merke seg at i forsøkene som representerer oppfinnelsen ble den samme blekningsgrad oppnådd som i referanse-forsøkene, noe som betyr at enzymbehanding ikke har noen ugunstig virkning på blekeresultatet. The results suggest that, compared to corresponding bleaching without enzyme treatment, the enzyme treatment combined with chlorine dioxide bleaching as provided according to the invention significantly reduces the pollution load caused by bleaching effluent as measured by the AOX and COD values. Compared to the commonly used chlorine bleaching, the improvement achieved is even more distinct. Furthermore, it is worth noting that in the experiments representing the invention the same degree of bleaching was achieved as in the reference experiments, which means that enzyme treatment has no adverse effect on the bleaching result.
Eksempel 2 Example 2
En fortynnet enzymblanding (streptomyces hemicellulase) ble satt til 220 g tørrstoff fra nåletre-sulf atmasse (med et tørrstoffinnhold på 30$) slik at det ble oppnådd en blanding med en konsistens på 10$ og en xylanase-aktivitet på 5 U/g masse tørrstoff. Temperaturen ved enzymbehandlingen var 55° C, behandlingsvarigheten 2 timer og pH verdien 8,5. A diluted enzyme mixture (streptomyces hemicellulase) was added to 220 g of dry matter from softwood sulfate pulp (with a dry matter content of 30$) so that a mixture with a consistency of 10$ and a xylanase activity of 5 U/g of pulp was obtained dry matter. The temperature during the enzyme treatment was 55° C, the treatment duration 2 hours and the pH value 8.5.
Efter enzymbehandl ingen ble massen vasket i en Btichnertrakt med en 20 ganger så stor mengde vann. After enzyme treatment, the pulp was washed in a Btichner funnel with a 20 times greater amount of water.
Efter vaskingen ble massen underkastet en oksydasjonsblekebe-handling ved bruk av en blanding som inneholdt 80$ klordioksyd og 20$ klorgass. Doseringen av blandingen var 1,4 x tallet for massen efter enzymbehandlingen. Behandlingstemperaturen var 57°C og behandlingsvarigheten var 45 minutter. Efter oksydasjonsfasen ble massen vasket i en Btichnertrakt med 20 ganger mengden vann. Derefter ble massen underkastet en alkalibehandling ved bruk av en 5$ natrium-hydroksydoppløsning i en mengde på 0,10 x kappa. Konsistensen i blandingen var 2%, behandlingstemperaturen 45 - 55"C og behandlingsvarigheten var 90 minutter. Efter alkalibehand-1 ingen ble massen vasket på samme måte som efter oksydasjonsfasen. After washing, the mass was subjected to an oxidation bleaching treatment using a mixture containing 80% chlorine dioxide and 20% chlorine gas. The dosage of the mixture was 1.4 x the figure for the mass after the enzyme treatment. The treatment temperature was 57°C and the treatment duration was 45 minutes. After the oxidation phase, the mass was washed in a Btichner funnel with 20 times the amount of water. Then the pulp was subjected to an alkali treatment using a 5% sodium hydroxide solution in an amount of 0.10 x kappa. The consistency of the mixture was 2%, the treatment temperature 45 - 55°C and the treatment duration was 90 minutes. After the alkali treatment, the mass was washed in the same way as after the oxidation phase.
Efter dette ble blekingen fortsatt ved gjentagelse av oksydasjons- og alkalifasene og derefter nok en gang oksydasjonsfasen og vasking av massen mellom disse faser som beskrevet ovenfor. For de kombinerte vaskevann bestemte man mengden organisk bundet klor AOX og det kjemiske oksygenbehov COD og resultatene er anført i tabell 2, forsøk 4, nedenfor. After this, the bleaching was continued by repeating the oxidation and alkali phases and then once again the oxidation phase and washing the mass between these phases as described above. For the combined washing waters, the amount of organically bound chlorine AOX and the chemical oxygen demand COD were determined and the results are listed in Table 2, experiment 4, below.
I tillegg til det ovenfor angitte forsøk 4 som illustrerer oppfinnelsen ble det gjennomført tre referanseforsøk, forsøkene 1 til 3, og AOX- og COD-verdiene for de kombinerte vaskevann oppnådd fra de forskjellige trinn i forsøkene, er også presentert i tabell 2. Forsøkene ble gjennomført som følger: Forsøk 3: Det ble ikke benyttet noen enzymbehandling. Doseringen av blekekjemikalier i forskjellige trinn av behandlingen under blekingen var 2 x , den vanligvis benyttede dosering. I andre henseende var forsøket analogt det som var beskrevet ovenfor (forsøk 4). In addition to the above-mentioned trial 4 which illustrates the invention, three reference trials were carried out, trials 1 to 3, and the AOX and COD values for the combined washing water obtained from the different steps in the trials are also presented in table 2. The trials were carried out as follows: Trial 3: No enzyme treatment was used. The dosage of bleaching chemicals in different stages of the treatment during the bleaching was 2 x , the usually used dosage. In other respects, the experiment was analogous to that described above (experiment 4).
Forsøk 2: Massen ble behandlet med et enzym som beskrevet ovenfor. Blekekjemikaliet som ble benyttet i oksyda-sjonsfasene var ren klorgass i en dosering på 2 x Ml • I andre henseende var forsøket analogt det som var beskrevet ovenfor (forsøk 4). Experiment 2: The pulp was treated with an enzyme as described above. The bleaching chemical used in the oxidation phases was pure chlorine gas in a dosage of 2 x Ml • In other respects, the experiment was analogous to that described above (experiment 4).
Forsøk 1: Det ble ikke benyttet noen enzymbehandling. Blekekjemikaliet som ble benyttet i denne oksydasjonsprosess var ren klorgass i en dosering på 2 x ^fC . I andre henseende var forsøket analogt det som var beskrevet ovenfor (forsøk 4)- Experiment 1: No enzyme treatment was used. The bleaching chemical used in this oxidation process was pure chlorine gas in a dosage of 2 x ^fC. In other respects, the experiment was analogous to that described above (experiment 4)-
Disse resultater antyder at, sammenlignet med tilsvarende bleking uten enzymbehandling, enzymbehandling kombinert med klordioksydbleking ifølge oppfinnelsen i vesentlig grad reduserer forurensningsbelastningen forårsaket av brukte blekevaesker målt ved AOX- og COD-verdiene. Sammenlignet med den vanligvis benyttede klorbleking er forbedringen som oppnås ennu mere utpreget. Det kan også sees at benyttet sammenlignet med klordioksydbleking gir enzymbehandlingen en meget mer distinkt forbedring enn når den benyttes i forbindelse med den konvensjonelle klordioksydbleking. Det skal være klart at også i dette tilfelle oppnås den samme blekegrad for massen i forsøket som representerer oppfinnelsen som i referanseforsøket, noe som betyr at enzymbehandlingen ikke hadde noen ugunstig virkning på blekeresultåtet. These results suggest that, compared to corresponding bleaching without enzyme treatment, enzyme treatment combined with chlorine dioxide bleaching according to the invention significantly reduces the pollution load caused by used bleaching liquids as measured by the AOX and COD values. Compared to the usually used chlorine bleaching, the improvement achieved is even more pronounced. It can also be seen that when used in comparison with chlorine dioxide bleaching, the enzyme treatment gives a much more distinct improvement than when it is used in connection with the conventional chlorine dioxide bleaching. It should be clear that in this case too, the same degree of bleaching is achieved for the pulp in the experiment representing the invention as in the reference experiment, which means that the enzyme treatment had no adverse effect on the bleaching result.
Det skal være åpenbart for en fagmann at forskjellige utførelsesformer av oppfinnelsen ikke er begrenset til de ovenfor gitte eksempler men at disse kan varieres innefor rammen av de ledsagende krav. For eksempel kan i alkalibe-handlingstrinnene i blekeprosessen, oksygen være tilstede i tillegg til alkali, og enzymbehandlingsvarigheten kan variere fra noen minutter til flere timer, for eksempel fra 5 minutter til 10 timer. It should be obvious to a person skilled in the art that different embodiments of the invention are not limited to the examples given above but that these can be varied within the scope of the accompanying claims. For example, in the alkali treatment steps of the bleaching process, oxygen may be present in addition to alkali, and the enzyme treatment duration may vary from a few minutes to several hours, for example from 5 minutes to 10 hours.
Claims (5)
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FI890700A FI90888B (en) | 1989-02-14 | 1989-02-14 | Method for bleaching cellulose pulp |
Publications (4)
| Publication Number | Publication Date |
|---|---|
| NO893714D0 NO893714D0 (en) | 1989-09-18 |
| NO893714L NO893714L (en) | 1990-08-15 |
| NO176406B true NO176406B (en) | 1994-12-19 |
| NO176406C NO176406C (en) | 1995-03-29 |
Family
ID=8527891
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| NO893714A NO176406C (en) | 1989-02-14 | 1989-09-18 | Method of Bleaching Mass |
Country Status (8)
| Country | Link |
|---|---|
| EP (1) | EP0383999B1 (en) |
| JP (1) | JPH02221482A (en) |
| AT (1) | ATE103351T1 (en) |
| CA (1) | CA1339594C (en) |
| DE (1) | DE68914135D1 (en) |
| ES (1) | ES2050747T3 (en) |
| FI (1) | FI90888B (en) |
| NO (1) | NO176406C (en) |
Families Citing this family (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FI86896B (en) * | 1989-05-04 | 1992-07-15 | Enso Gutzeit Oy | FOERFARANDE FOER BLEKNING AV CELLULOSAMASSA. |
| SE465320B (en) * | 1990-01-10 | 1991-08-26 | Korsnaes Ab | PREPARATIONS SUBMITTING ENZYMATIC DELIGNIFICATION ACTIVITY, MADE TO MAKE THE SAME AND APPLICATIONS THEREOF |
| FI89814C (en) * | 1990-02-02 | 1993-11-25 | Enso Gutzeit Oy | FOERFARANDE FOER BLEKNING AV CELLULOSAMASSA |
| US5837515A (en) * | 1990-05-16 | 1998-11-17 | Alko-Yhtiot Oy | Enzyme preparations and methods for their production |
| JP2859393B2 (en) * | 1990-07-24 | 1999-02-17 | ノボ ノルディスク アクティーゼルスカブ | Cellulase and method for producing the same |
| DK203490D0 (en) * | 1990-08-24 | 1990-08-24 | Novo Nordisk As | PROCEDURE FOR TREATING LIGNOCELLULOS PULP AND APPARATUS FOR PERFORMING THE PROCESS |
| DE4129739A1 (en) * | 1990-09-11 | 1992-03-12 | Sandoz Ag | Chlorine-free bleaching of paper pulp |
| FI108800B (en) * | 1991-05-07 | 2002-03-28 | Iogen Corp | A method and apparatus for using an enzyme in the manufacture and bleaching of pulp |
| CA2044100A1 (en) * | 1991-06-07 | 1992-12-08 | Janice Hamilton | Biobleaching process |
| US5369024A (en) * | 1992-03-25 | 1994-11-29 | The United States Of America As Represented By The Secretary Of Agriculture | Xylanase from streptomyces roseiscleroticus NRRL-11019 for removing color from kraft wood pulps |
| US5498534A (en) * | 1992-03-25 | 1996-03-12 | The United States Of America As Represented By The Secretary Of Agriculture | Method of removing color from wood pulp using xylanase from streptomyces roseiscleroticus NRRL B-11019 |
| DE4422307A1 (en) * | 1994-06-17 | 1995-12-21 | Melitta Haushaltsprodukte | Process for delignifying and bleaching unbleached pulp suspensions using nitrogen compounds |
| US5935836A (en) * | 1994-07-29 | 1999-08-10 | Rohm Enzyme Finland Oy | Actinomadura xylanase sequences and methods of use |
| US7816129B2 (en) | 1994-07-29 | 2010-10-19 | Ab Enzymes Gmbh | Production and secretion of proteins of bacterial origin in filamentous fungi |
| US5871730A (en) * | 1994-07-29 | 1999-02-16 | Universite De Sherbrooke | Thermostable xylanase DNA, protein and methods of use |
| US6300114B1 (en) | 1994-07-29 | 2001-10-09 | Rohm Enzyme Finland Oy | Sequences of xylanase and xylanase expression vectors |
| WO2002057541A2 (en) | 2001-01-18 | 2002-07-25 | Iogen Bio-Products Corporation | Use of xylanase in pulp bleaching |
| WO2003074780A1 (en) * | 2002-03-06 | 2003-09-12 | Iogen Bio-Products Corporation | Xylanase treatment of chemical pulp |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA1086905A (en) * | 1977-10-25 | 1980-10-07 | W. Howard Rapson | Bleach plant operation |
| JPS5468402A (en) * | 1977-11-09 | 1979-06-01 | Kogyo Gijutsuin | Property modification of biochemical pulp |
| FI81395B (en) * | 1988-03-14 | 1990-06-29 | Cultor Oy | FOERFARANDE FOER BLEKNING AV CELLULOSAMASSA. |
-
1989
- 1989-02-14 FI FI890700A patent/FI90888B/en not_active Application Discontinuation
- 1989-09-18 ES ES89117235T patent/ES2050747T3/en not_active Expired - Lifetime
- 1989-09-18 DE DE89117235T patent/DE68914135D1/en not_active Expired - Lifetime
- 1989-09-18 AT AT89117235T patent/ATE103351T1/en not_active IP Right Cessation
- 1989-09-18 NO NO893714A patent/NO176406C/en not_active IP Right Cessation
- 1989-09-18 JP JP1241667A patent/JPH02221482A/en active Pending
- 1989-09-18 EP EP89117235A patent/EP0383999B1/en not_active Revoked
- 1989-09-18 CA CA000611773A patent/CA1339594C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| FI890700A0 (en) | 1989-02-14 |
| EP0383999A3 (en) | 1990-12-12 |
| EP0383999A2 (en) | 1990-08-29 |
| FI90888B (en) | 1993-12-31 |
| DE68914135D1 (en) | 1994-04-28 |
| NO893714L (en) | 1990-08-15 |
| EP0383999B1 (en) | 1994-03-23 |
| NO893714D0 (en) | 1989-09-18 |
| ATE103351T1 (en) | 1994-04-15 |
| JPH02221482A (en) | 1990-09-04 |
| CA1339594C (en) | 1997-12-23 |
| NO176406C (en) | 1995-03-29 |
| FI890700A (en) | 1990-08-15 |
| ES2050747T3 (en) | 1994-06-01 |
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