NO801311L - PROCEDURE FOR DESODORING CONDUCTING CONDENSATES IN THE CELLULOSE INDUSTRY - Google Patents
PROCEDURE FOR DESODORING CONDUCTING CONDENSATES IN THE CELLULOSE INDUSTRYInfo
- Publication number
- NO801311L NO801311L NO801311A NO801311A NO801311L NO 801311 L NO801311 L NO 801311L NO 801311 A NO801311 A NO 801311A NO 801311 A NO801311 A NO 801311A NO 801311 L NO801311 L NO 801311L
- Authority
- NO
- Norway
- Prior art keywords
- condensates
- evaporation
- hydrogen peroxide
- cellulose
- desodoring
- Prior art date
Links
- 238000000034 method Methods 0.000 title claims abstract description 17
- 239000001913 cellulose Substances 0.000 title claims abstract description 14
- 229920002678 cellulose Polymers 0.000 title claims abstract description 14
- 238000001704 evaporation Methods 0.000 claims abstract description 26
- 230000008020 evaporation Effects 0.000 claims abstract description 26
- 230000029087 digestion Effects 0.000 claims abstract description 11
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims description 36
- 238000009833 condensation Methods 0.000 claims description 2
- 230000005494 condensation Effects 0.000 claims description 2
- 238000005259 measurement Methods 0.000 claims description 2
- 238000011437 continuous method Methods 0.000 claims 1
- 230000001877 deodorizing effect Effects 0.000 claims 1
- 239000000126 substance Substances 0.000 abstract description 11
- 238000004332 deodorization Methods 0.000 abstract 1
- 238000002360 preparation method Methods 0.000 abstract 1
- 238000011084 recovery Methods 0.000 abstract 1
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 8
- 238000005406 washing Methods 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
- LSNNMFCWUKXFEE-UHFFFAOYSA-M Bisulfite Chemical compound OS([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-M 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 2
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 2
- 239000012190 activator Substances 0.000 description 2
- 239000000460 chlorine Substances 0.000 description 2
- 229910052801 chlorine Inorganic materials 0.000 description 2
- 238000010790 dilution Methods 0.000 description 2
- 239000012895 dilution Substances 0.000 description 2
- OSVXSBDYLRYLIG-UHFFFAOYSA-N dioxidochlorine(.) Chemical compound O=Cl=O OSVXSBDYLRYLIG-UHFFFAOYSA-N 0.000 description 2
- 238000011010 flushing procedure Methods 0.000 description 2
- HYBBIBNJHNGZAN-UHFFFAOYSA-N furfural Chemical compound O=CC1=CC=CO1 HYBBIBNJHNGZAN-UHFFFAOYSA-N 0.000 description 2
- WQYVRQLZKVEZGA-UHFFFAOYSA-N hypochlorite Chemical compound Cl[O-] WQYVRQLZKVEZGA-UHFFFAOYSA-N 0.000 description 2
- 230000035484 reaction time Effects 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- LSNNMFCWUKXFEE-UHFFFAOYSA-L sulfite Chemical compound [O-]S([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-L 0.000 description 2
- ZFFTZDQKIXPDAF-UHFFFAOYSA-N 2-Furanmethanethiol Chemical compound SCC1=CC=CO1 ZFFTZDQKIXPDAF-UHFFFAOYSA-N 0.000 description 1
- 239000004155 Chlorine dioxide Substances 0.000 description 1
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229940075397 calomel Drugs 0.000 description 1
- 235000019398 chlorine dioxide Nutrition 0.000 description 1
- 229910001919 chlorite Inorganic materials 0.000 description 1
- 229910052619 chlorite group Inorganic materials 0.000 description 1
- QBWCMBCROVPCKQ-UHFFFAOYSA-N chlorous acid Chemical compound OCl=O QBWCMBCROVPCKQ-UHFFFAOYSA-N 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 159000000014 iron salts Chemical class 0.000 description 1
- 239000001095 magnesium carbonate Substances 0.000 description 1
- ZLNQQNXFFQJAID-UHFFFAOYSA-L magnesium carbonate Chemical compound [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 description 1
- 229910000021 magnesium carbonate Inorganic materials 0.000 description 1
- 235000014380 magnesium carbonate Nutrition 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- 229910052938 sodium sulfate Inorganic materials 0.000 description 1
- 235000011152 sodium sulphate Nutrition 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 239000002351 wastewater 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
- D21C11/00—Regeneration of pulp liquors or effluent waste waters
- D21C11/06—Treatment of pulp gases; Recovery of the heat content of the gases; Treatment of gases arising from various sources in pulp and paper mills; Regeneration of gaseous SO2, e.g. arising from liquors containing sulfur compounds
- D21C11/08—Deodorisation ; Elimination of malodorous compounds, e.g. sulfur compounds such as hydrogen sulfide or mercaptans, from gas streams
Abstract
Fremgangsmåter til desodorering av inndampnings-konder.sater i celluloseindustrien.De ved gjenvinning av kjemikalier ved celluloseoppslutningen dannede sterktluktende inndampningskondensater blir fullstendig desodorert alene ved tilsetning av hydrogenperoksyd, dvs. uten tilsetning av et metallsalt som aktivator og kan med en gang anvendes enten som vaskevann ved opp-arbeidelse av oppslutningsavluten til kjemikaliegjenvinning eller også tilføres direkte til avvanningsgrøften.Processes for the deodorization of evaporation condensates in the cellulose industry preparation of the digestion effluent for chemical recovery or also fed directly to the drainage ditch.
Description
For å holde de i celluloseoppslutningsoppløsningen inneholdte kjemikalier samt de oppløste organiske stoffer borte fra avvanningsgrøften, må avluten av celluloseoppslut-ningsprbsessen opparbeides, se Ullmann, "EnzyklopSdie der technischen Chemie", bd. 18, 1967, s. 761. In order to keep the chemicals contained in the cellulose digestion solution as well as the dissolved organic substances away from the drainage ditch, the effluent from the cellulose digestion process must be processed, see Ullmann, "EnzyklopSdie der technischen Chemie", vol. 18, 1967, p. 761.
For dette formål vaskes avluten f.eks. i et fleretrinns vaskeanlegg, idet det fremkommer den såkalte tynnlut (se Ullmann sitert ovenforl som konsentreres ved hjelp av vannavdamper. For this purpose, the effluent is washed, e.g. in a multi-stage washing plant, as the so-called thin liquor (see Ullmann cited above) is produced which is concentrated using a water evaporator.
De etter kondensasjonen av disse damper dannede såkalte inndampningskondensater har en meget sterk luktemisjon. og dette er tilfelle for inndampningskondensatene av alle oppslutningsfremgangsmåter for cellulose, dvs. så vel for inndampningskondensater av sulfitt- eller bisulfittopp-slutningen som også for kondensatene fra alkaliske oppslut-ninger med soda eller natriumsulfat, se Ullmann ovennevnte sitat, s. 754-756, 765, 770-771. The so-called evaporation condensates formed after the condensation of these vapors have a very strong odor emission. and this is the case for the evaporation condensates of all digestion methods for cellulose, i.e. as well as for evaporation condensates from the sulphite or bisulphite digestion as well as for the condensates from alkaline digestions with soda or sodium sulphate, see Ullmann above-mentioned quote, pp. 754-756, 765, 770-771.
De .nevnte inndampningskondensater inneholder ved siden av svoveldioksyd dessuten metanol, furfurol, eddiksyre og visse meget luktintensive stoffer som f.eks. etyl- og furfurylmerkaptan.. In addition to sulfur dioxide, the aforementioned evaporation condensates also contain methanol, furfural, acetic acid and certain very odor-intensive substances such as e.g. ethyl and furfuryl mercaptan..
På grunn av den sterke lukt strandet hittil forsøk på å tilbakeføre disse kondensater igjen i celluloseoppslutningens kretsløp f.eks. som vaskevann. Due to the strong smell, attempts to return these condensates back into the cellulose digester's circuit, e.g. as washing water.
Riktignok kan under anvendelse av meget store damp-mengder en del av de luktintensive stoffer strippes fra inndampningskondensatene, imidlertid er det ved siden av den hertil nødvendige damp dessuten nødvendig med ekstra appara-tive innretninger. Dessuten var kondensatene på tross av denne behandling ikke fri for vond lukt. Admittedly, by using very large quantities of steam, a part of the odor-intensive substances can be stripped from the evaporation condensates, however, in addition to the steam required for this purpose, additional equipment is also required. Moreover, despite this treatment, the condensates were not free of bad odours.
Riktignok ble det allerede også forsøkt å behandle inndampningskondensatene med klorvann eller hypokloritt- Admittedly, attempts were already made to treat the evaporation condensates with chlorine water or hypochlorite
resp. klorittoppløsninger, imidlertid oppsto derved nye lukt-belastninger på grunn av overskytende klor resp. dannelse av klordioksyd. Dessuten ble inndampningskondensatene korrosive ved denne behandling og lot seg ikke mere anvende i kretsløpsfremgangsmåten ved celluloseoppslutningen. respectively chlorite solutions, however, this resulted in new odor burdens due to excess chlorine or formation of chlorine dioxide. In addition, the evaporation condensates became corrosive during this treatment and could no longer be used in the circuit method for cellulose digestion.
Hensikten med oppfinnelsen er å tilveiebringe en fremgangsmåte hvorved inndampningskondensatene luktintensive stoffer kan uskadeliggjøres uten ekstra apparativ innsats. The purpose of the invention is to provide a method by which the evaporation condensates of odor-intensive substances can be made harmless without additional equipment effort.
Det er nå funnet at inndampningskondensater som fremkommer ved celluloseindustriens oppslutningsfremgangsmåter praktisk talt fullstendig kan befris for de inneholdte luktintensive stoffer kontinuerlig når man til inndampningskondensatene setter hydrogenperoksyd ved temperaturer på 20-95°C. It has now been found that evaporation condensates produced by the cellulose industry's digestion methods can be practically completely freed of the contained odor-intensive substances continuously when hydrogen peroxide is added to the evaporation condensates at temperatures of 20-95°C.
Derved anvendes 0,05 - 2 kg hydrogenperoksyd (100 vekt-%-ig}, fortrinnsvis 0,05 - 0,2 kg hydrogenperoksyd Thereby, 0.05 - 2 kg of hydrogen peroxide (100% by weight, preferably 0.05 - 0.2 kg of hydrogen peroxide) is used
(100 vekt-%-ig) pr. 1000 kg inndampningskondensat. (100% by weight) per 1000 kg of evaporation condensate.
Reaksjonstiden utgjør 0,5 - 240 minutter alt etter konsentrasjonen av de tilstedeværende luktintensive stoffer og den anvendte mengde hydrogenperoksyd. The reaction time is 0.5 - 240 minutes, depending on the concentration of the odor-intensive substances present and the amount of hydrogen peroxide used.
De beste mengder hydrogenperoksyd og den beste inn-virkningstid kan lett fastslås ved hjelp av et forforsøk. The best amounts of hydrogen peroxide and the best exposure time can easily be determined with the help of a preliminary trial.
Et slikt forsøk er også å anbefale, fordi inndampningskondensatene ved siden av de luktintensive stoffer som skal oksyderes, dessuten som allerede nevnt inneholder andre oksyderbare forbindelser, fremfor alt svoveldioksyd. Ved for stor mengde svoveldioksyd kan derfor inndampningskondensatene f$r behandlingen med hydrogenperoksyd ved stripping med vanndamp befris for,en del eller fullstendig for SO 2 Such an attempt is also recommended, because the evaporation condensates next to the odor-intensive substances to be oxidized also, as already mentioned, contain other oxidizable compounds, above all sulfur dioxide. If there is too much sulfur dioxide, the evaporation condensates before the treatment with hydrogen peroxide can be partially or completely freed of SO 2 by stripping with steam
og også andre lett flyktige stoffer for å nedsette mengden hydrogenperoksyd som skal anvendes.. Den derved anvendte dampmengde ligger langt under den mengde som tidligere ble anvendt, men aldri førte til effektiv fjerning av de luktintensive stoffer. and also other easily volatile substances in order to reduce the amount of hydrogen peroxide to be used. The amount of steam thus used is far below the amount that was previously used, but never led to effective removal of the odor-intensive substances.
Også en kort luftgjennomblåsning kan nedsette SC^-mengden. A short air blow-through can also reduce the amount of SC^.
Det er også mulig å sette hydrogenperoksydet til ikke samtlige dannede kondensater, men ved mindre luktbelast-ning bare til de sterkest belastede kondensater. Selvsagt kan inndampningskondensatene også forenes til et eneste kondensat og dette deretter behandles vetter metoden ifølge oppfinnelsen. It is also possible to add the hydrogen peroxide to not all the condensates formed, but in the case of a smaller odor load only to the most strongly loaded condensates. Of course, the evaporation condensates can also be combined into a single condensate and this is then treated according to the method according to the invention.
Det kunne ikke forutsees at ved enkel tilblanding av hydrogenperoksyd startet oksydasjonsreaksjonen uten tilsetning av aktivatorer som f.eks. jernsalter i løpet av kort tid og var avsluttet kort til relativt kort tidsrom. It could not be foreseen that by simply adding hydrogen peroxide the oxidation reaction started without the addition of activators such as e.g. iron salts within a short time and was finished shortly to a relatively short time.
De oksyderte inndampningskondensater behandlet ifølge oppfinnelsen kan tilbakeføres i celluloseoppslutningens kretsløp f.eks. som vaskevann i ovennevnte vaskeanlegg for avlut. Dette betyr en større vannbesparelse. The oxidized evaporation condensates treated according to the invention can be returned to the cellulose digestion circuit, e.g. as washing water in the above-mentioned washing plant for waste liquor. This means greater water savings.
Videre kan disse kondensater, da de er fri for ekstra aktivatorer også anvendes til spyling av selve inn-dampningsanlegget. Furthermore, these condensates, as they are free of additional activators, can also be used for flushing the evaporation plant itself.
Også innføring.av kondensatene behandlet ifølge oppfinnelsen i avvanningsgrøfter er det intet i veien for på grunn av luktemisjon. There is also nothing to prevent the introduction of the condensates treated according to the invention into drainage ditches due to odor emission.
Doseringen av hydrogenperoksyd foregår på vanlig måte, fortrinnsvis ved hjelp av redoks-målinger. The dosage of hydrogen peroxide takes place in the usual way, preferably by means of redox measurements.
Fremgangsmåten lar seg anvende for inndampningskondensatene av alle ovennevnte oppslutningsfremgangsmåter for cellulose, dvs. så vel for sulfitt-, bisulfitt- som også for de alkaliske fremgangsmåter. Meget gode resultater ble f.eks. oppnådd ved sure magnesitbisulfitt-fremgangsmåter. The method can be used for the evaporation condensates of all the above-mentioned digestion methods for cellulose, i.e. both for sulphite, bisulphite and also for the alkaline methods. Very good results were e.g. obtained by acid magnesite bisulphite processes.
EksempelExample
I en cellulosefabrikk frembringes daglig 500 tonn "Magnefite"-cellulose, avluten bringes i et fleretrinns inndampningsanlegg til 58 % tørrinnhold og forbrennes. Pr. time fremkommer følgende kondensatmengder i forskjellige inndampningstrinn med unntak av det såkalte Kondensat 1 In a cellulose factory, 500 tonnes of "Magnefite" cellulose is produced daily, the effluent is brought in a multi-stage evaporation plant to a dry content of 58% and incinerated. The following amounts of condensate appear per hour in different evaporation stages, with the exception of the so-called Condensate 1
som ikke ble behandlet: Såkalt Kondensat 2+3 (minste belastning) 120 tonn/time Såkalt kondensat 4+5 (midlere belastning) 70 tonn/time Såkalt etterkondensater (sterk belastning which were not treated: So-called Condensate 2+3 (least load) 120 tons/hour So-called condensate 4+5 (medium load) 70 tons/hour So-called post-condensates (heavy load
under tiden også med SO2) 10 tonn/time Kondensatene 2+3 og 4+5 har en intens muggen lukt som i sterkere fortynning har en likhet med kaffegrut-lukt. Ettérkondensatene inneholdt de lettest vanndampflyktige forurensninger. Dens lukt er intenst stikkende, fortynningen likeledes muggen kaffe-lignende. meanwhile also with SO2) 10 tonnes/hour The condensates 2+3 and 4+5 have an intense musty smell which, in stronger dilution, resembles a coffee grounds smell. The after-condensates contained the most easily water-vapour-volatile pollutants. Its smell is intensely pungent, the dilution likewise musty coffee-like.
I kondensatledningen inndoseres like før inntreden i transportpumpen hydrogenperoksyd (50 vekt-%-ig). Etter, transportpumpen måles ved hjelp av en platina-kalomel-elektrode stadig potensialet. De doserte hydrogenperoksyd-mengder i kondensatene 2 +3 er ca. 400 ml/min. ved innregu-ler ing til 220 mV, i kondensatene 4 + 5 ca. 4 00 ml/min. ved innregulering til 250 mV, i etterkondensatene ca. 500 ml/min. ved innregulering til 150 mV. Kondensatene 2+3 anvendes til spyling av anlegget. Reaksjonstiden etter tilsetning av hydrogenperoksyd utgjør ca. 15 minutter,. Just before entering the transport pump, hydrogen peroxide (50% by weight) is dosed into the condensate line. After, the transport pump is measured using a platinum-calomel electrode constantly the potential. The dosed amounts of hydrogen peroxide in the condensates 2 +3 are approx. 400 ml/min. by adjusting to 220 mV, in the condensates 4 + 5 approx. 400 ml/min. when adjusted to 250 mV, in the post-condensates approx. 500 ml/min. when adjusted to 150 mV. The condensates 2+3 are used for flushing the plant. The reaction time after adding hydrogen peroxide amounts to approx. 15 minutes,.
Kondensatene 4 + 5' forenes med etterkondensatene og oppbevares i en holder av edelstål 1-2 timer. Tempera-turene ligger mellom 65-95°C. Etter denne behandling er den typiske ubehagelige under tiden stikkende lukt helt fjernet. Den gjenblivende svakt blomsteraktige lukt finnes behagelig og er ingen belastning. De oksyderte kondensater anvendes til vasking av cellulosene i lutoppfangingén. De går dermed for en stor del tilbake i inndampningen og danner dermed ingen belastning av fabrikasjonsavvannet. De angitte potensialer ble oppnådd ved forforsøk. The condensates 4 + 5' are combined with the subsequent condensates and kept in a stainless steel holder for 1-2 hours. The temperature ranges are between 65-95°C. After this treatment, the typical unpleasant and sometimes pungent smell is completely removed. The remaining slightly floral smell is pleasant and is not a burden. The oxidized condensates are used for washing the cellulose in the lye collection unit. They thus go back to a large extent in the evaporation process and thus create no burden on the manufacturing wastewater. The indicated potentials were obtained in preliminary experiments.
Claims (4)
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19792928652 DE2928652A1 (en) | 1979-07-16 | 1979-07-16 | METHOD FOR THE DESODORATION OF EVAPORATION CONDENSATES IN THE PULP INDUSTRY |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| NO801311L true NO801311L (en) | 1981-01-19 |
Family
ID=6075827
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| NO801311A NO801311L (en) | 1979-07-16 | 1980-05-05 | PROCEDURE FOR DESODORING CONDUCTING CONDENSATES IN THE CELLULOSE INDUSTRY |
Country Status (8)
| Country | Link |
|---|---|
| AT (1) | AT375108B (en) |
| CA (1) | CA1139507A (en) |
| CH (1) | CH645147A5 (en) |
| DE (1) | DE2928652A1 (en) |
| FR (1) | FR2461777A1 (en) |
| IT (1) | IT1128928B (en) |
| NO (1) | NO801311L (en) |
| SE (1) | SE445654B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4442226A1 (en) * | 1994-11-26 | 1995-06-14 | Goes Ges Fuer Sanierungsmasnah | Thixotropic sludge decontamination contg. lignin esp. from pulp mfr. |
| SE531478C2 (en) * | 2007-11-26 | 2009-04-21 | Processum Biorefinery Initiative Ab | Process for the extraction of ammonium salt and methanol from liquid emanating from impure condensate resulting from cellulose pulp production |
| US20150322626A1 (en) | 2014-05-06 | 2015-11-12 | Weyerhaeuser Nr Company | Reduced furfural content in polyacrylic acid crosslinked cellulose fibers |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE176690C (en) * | ||||
| DE218344C (en) * | ||||
| DE340126C (en) * | 1919-02-27 | 1921-09-01 | Ludwig Schmidt Dr | Process for improving the smell of Sulphatterpentinoel |
| US2409614A (en) * | 1942-01-15 | 1946-10-22 | Hercules Powder Co Ltd | Refining sulfate turpentine |
| US3705098A (en) * | 1971-02-22 | 1972-12-05 | Fmc Corp | Sewage treatment with hydrogen peroxide |
| FR2192981B1 (en) * | 1972-07-21 | 1988-11-10 | Air Liquide Fr | |
| US3796628A (en) * | 1972-09-12 | 1974-03-12 | Cariboo Pulp And Paper Co | Method for reducing sulfide odors from kraft mill lime kiln stacks |
-
1979
- 1979-07-16 DE DE19792928652 patent/DE2928652A1/en not_active Withdrawn
-
1980
- 1980-04-14 FR FR8008322A patent/FR2461777A1/en active Granted
- 1980-04-24 CA CA000350593A patent/CA1139507A/en not_active Expired
- 1980-05-05 NO NO801311A patent/NO801311L/en unknown
- 1980-07-10 IT IT68096/80A patent/IT1128928B/en active
- 1980-07-15 CH CH543880A patent/CH645147A5/en not_active IP Right Cessation
- 1980-07-15 AT AT0367680A patent/AT375108B/en not_active IP Right Cessation
- 1980-07-15 SE SE8005174A patent/SE445654B/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| SE445654B (en) | 1986-07-07 |
| AT375108B (en) | 1984-07-10 |
| IT8068096A0 (en) | 1980-07-10 |
| ATA367680A (en) | 1983-11-15 |
| CH645147A5 (en) | 1984-09-14 |
| FR2461777B1 (en) | 1984-10-19 |
| FR2461777A1 (en) | 1981-02-06 |
| SE8005174L (en) | 1981-01-17 |
| IT1128928B (en) | 1986-06-04 |
| DE2928652A1 (en) | 1981-02-19 |
| CA1139507A (en) | 1983-01-18 |
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