EP0091457A1 - Verfahren zur polysulfidbehandlung im alkalischen pulpverfahren von lignocellulosematerial. - Google Patents

Verfahren zur polysulfidbehandlung im alkalischen pulpverfahren von lignocellulosematerial.

Info

Publication number
EP0091457A1
EP0091457A1 EP82903084A EP82903084A EP0091457A1 EP 0091457 A1 EP0091457 A1 EP 0091457A1 EP 82903084 A EP82903084 A EP 82903084A EP 82903084 A EP82903084 A EP 82903084A EP 0091457 A1 EP0091457 A1 EP 0091457A1
Authority
EP
European Patent Office
Prior art keywords
liquor
polysulphide
digestion
chips
white
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP82903084A
Other languages
English (en)
French (fr)
Other versions
EP0091457B1 (de
Inventor
Nils V Mannbro
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to AT82903084T priority Critical patent/ATE24556T1/de
Publication of EP0091457A1 publication Critical patent/EP0091457A1/de
Application granted granted Critical
Publication of EP0091457B1 publication Critical patent/EP0091457B1/de
Expired legal-status Critical Current

Links

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
    • D21C11/0057—Oxidation of liquors, e.g. in order to reduce the losses of sulfur compounds, followed by evaporation or combustion if the liquor in question is a black liquor
    • 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
    • D21C3/02—Pulping cellulose-containing materials with inorganic bases or alkaline reacting compounds, e.g. sulfate processes
    • D21C3/022—Pulping cellulose-containing materials with inorganic bases or alkaline reacting compounds, e.g. sulfate processes in presence of S-containing compounds

Definitions

  • Berthier also dealt with the subject of recovering sulphur dioxide in flue gas from combustion of black liquor in furnaces for recovery of sulphide-containing soda smelt.
  • the sulphur dioxide is then converted with hydrogen sulphide originating from the smelt for generating elementary sulphur.
  • the oxidation is carried out such that a considerable portion of the (mono-) sulphide of the mixture is transformed into polysulphide.
  • the liquor mixture is then charged to the wood.
  • Union Camp Corporation discloses in Swedish patent Application No. 72 03993-6 (published specification No. 381 691) a method invented by Barker. Chips are impregnated with white liquor, and then black liquor is added.
  • the sulphide of the liquor mixture is oxidized to polysulphide by means of a gas containing gaseous oxygen.
  • the delignification of the wood then takes place with the entire volume of liquor and chips.
  • black liquor is recovered from the pulp in a conventional washing step which means that the portion of black liquor that is not recycled to the digestion plant for the polysulphide oxidation is conveyed from the pulp washing to the evaporation and combustion stages.
  • the black liquor charged to the digestion step is often of the same kind as that conveyed from the pulp wash to the evaporation plant.
  • the total recovered black liquor volume from the pulp wash is 4 a 5 m 3 per ton of wood, and thus only one fourth of the black liquor substance is as indicated above recycled to the digestion stage.
  • only about one fourth of the monosulphide present in the digestion stage would, at the most, be available for oxidation of black liquor to polysulphide according to known technique.
  • polysulphide is reverted to monosulphide during the digestion. Sulphide absorbed from the liquor by the wood as organic compounds is solubi lized towards the end of the digestion stage and some sulphide is split off. Thio-sulphate generated by non-desired reactions during the preparation of polysulphide may revert partially to monosulphide in the digestion stage.
  • the present invention relates to a method of preparing poly-sulphide of practically the whole volume of the used digestion liquor or black liquor, respectively, from the preceding digestion, the white liquor then being completely or partially charged to the lignocellulose material or pulp being delignified.
  • Recovered black liquor is not diverted directly from the pulp to the stages of alkali regeneration, i.e. evaporation and combustion steps, but from stages for pretreatment of the wood chips to said alkali generation steps.
  • Polysulphide treatment of wood chips can be carried out batchwise or continuously when connected to batch digestion. In continuous .digestion only continuous pre-treatment should be of interest.
  • polysulphide treatment liquor is circulated through the chips via an external pipe system and oxygen is injected immediately before the liquor enters the treatment vessel. Since according to the invention ultimate black liquor is recovered after the polysulphide reaction with chips, other liquors used in the digester liquor circulation system subsequently to the polysulphide stage are referred to as digestion liquor or spent digestion liquor or just spent liquor.
  • a digestion method preferred for the invention is the digestion method described in Swedish patent No. 73 15894-1.
  • the present invention is applicable in general for such an operation of a cooking liquor system for multiple digesters, irrespective of the presence of a possible subsequent bleach ing.
  • Sulphide-carrying white liquor is thus dosed to digestion liquor containing black liquor components and which cooking liquor being circulated through a multiple of digesters with various contents of partially delignified wood or pulp, respectively.
  • a digester filled with fresh wood chips is charged with digestion liquor and then shut off from the common cooking liquor circulation system of the digesters.
  • a mixture temperature of wood chips and digestion liquor is arrived at, and a rapid consumption of the alkali of the black liquor takes place.
  • oxygen or oxygen containing gas is injected and conveyed through the content of the digester, preferably into circulating liquor, whereby the generation of polysulphide will be at a maximum. This takes place when about half of the sum of monosulphide and reactable organic sulphide compounds has been converted. If the oxidization is continued the polysulphide is oxidized further to thiosulphate.
  • Black liquor is successively reused according to the invention and the carbohydrate components of the wood react directly with the generated polysulphide. Therefore it is not purposeful to perform analyses of separate liquor samples afterwards.
  • a measure of the efficiency of the polysulphide generation is obtained by relating the increase of the yield of cellulose in the pulp to the content of the liquor of the polysulphide stage of 1) total amount of sulphur in various sulphur compounds of black liquor solids present in digestion liquor and 2) sodium. These substances have to a large extent passed previous digestion stages while a minor portion thereof may have been immediately transferred from white liquor charged to digestion liquor.
  • the wood chips rapidly absorb or consume, respectively, the content of hydroxide of the digestion liquor.
  • the pH of the spent digestion liquor is lowered and during the polysulphide oxidation Ph is further decreased.
  • the yield gain is improved as compared to that normally obtained by polysulphide reaction alone. The comparison is based on pulps of the same degree of delignification from same lot of wood chips.
  • 73 15894-1 and 74 06537-6 chips are reacted with black liquor which is removed prior to digestion to produce pulp which is subjected to further delignification with oxygen in oxy-stages in the presence of hydroxide-generating sodium compounds.
  • Oxy-liquor is extracted from the obtained oxy-pulp.
  • This delignification method may advantageously be applied to the present invention in such a way that oxy-liquor is passed completely or partially through the polysulphide stage. Thereby a yield increment of oxy-pulp was indicated as compared to that obtained in the case wherein oxy-liquor was not conveyed to the polysulphide stage.
  • the concentration of oxydizable sulphur compounds in the surrounding black liquor decreases in the course of reaction of the various sulphides with wood. Approximately between 1/5 and 1/2 of the reacted sulphide compunds accompany the wood to the subsequent digestion stage in which they are re-dissolved in digestion liquor. They will recirculate according to a liquor volume equilibrium in the digester system which, according to the invention, is determined by the reactions of digestion liquor and black liquor, respectively, with charged wood material. This equilibrium is governed by the fact that black liquor which is subjected to regeneration of its chemicals is first utilized for polysulphide reactions with the chips. The known methods, however, utilize only the fraction of black liquor required for subsequent digestion.
  • the method was modified in such a way that white and black liquor was first charged to the wood chips.
  • the mixed liquor was circulated through the batch of chips and simultaneously air was supplied into the digester from below for one hour. During this period the temperature dropped to about 80°C.
  • the capacity of the digestion plant was reduced to 85% of normal in spite of the fact that the maximum digestion temperature was raised from 170 to 176°C and the charge of white liquor was increased to 190 kg of EA per ton of wood.
  • the generation of polysulphide could not be determined by analysis of the liquor mixture, due to its instantaneous reaction with the chips.
  • the pulp was alkali-oxygen delignified.
  • the amount of oxy-pulp increased by 1% as calculated on the obtained pulp from the same quantity of wood as according to Example 1.
  • Example 3 The batch digestion plant was equipped with a digestion liquor accumulator as described in Swedish patent No. 73 15894-1. Used liquor in the form of digestion liquor the digesters with chips. Each digester was completely with the digesters with chips. Each digester was completely filled with liquor and finally the same pressure was reached as that in the digestion liquor accumulator. Oxygen containi gas was introduced from a gas circulation system through nozzles in the bottom zone of the digester while the liquor was circulated through the digester content.
  • thio sulphate is enriched which only to a small extent reacts with the wood but can to some extent revert to sulphide via reactions in which a number of other sulphur compounds participate.
  • Sulphur compounds which do not affect the pulp yield were gradually passed to the chemical generation plant with the removed black liquor which also contained a certain amount of polysulphide and regenerable sulphide.
  • the wood chips were weighed and moisture content measured. The quantity of bleached pulp obtained therefrom was determined in the same way. On basis of consumed wood quantity it was calculated that the method according to the invention produced 2.5% more pulp than when the chips only were reacted with the black liquor portion which was recirculated to the digestion stage.
  • Polysulphide treatment according to the invention produced pulp which was bleached more easily than conventional pulp to the target brightness of 92 SCAN. Therefore more delignification could be transferred from digestion to the oxy-stage. Thus it was found advantageous to adjust to the maximum digestion temperature down to 170°C that was used in conventional digestion and reduce the charge of EA to 160 kg per ton of wood.
  • Example 4
  • Chlorine dioxide for pulp bleaching was produced electrolyticallywith supply of hydrochloric acid.
  • Sodium hydroxide liquor for bleaching was regenerated according to Swedish patent No. 69 09674-1.
  • the polysulphide reaction of the chips can be carried out with spent digestion liquor, i.e. in the digestion used liquor, and consisting of

Landscapes

  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Paper (AREA)
EP82903084A 1981-10-21 1982-10-13 Verfahren zur polysulfidbehandlung im alkalischen pulpverfahren von lignocellulosematerial Expired EP0091457B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT82903084T ATE24556T1 (de) 1981-10-21 1982-10-13 Verfahren zur polysulfidbehandlung im alkalischen pulpverfahren von lignocellulosematerial.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE8106203A SE8106203L (sv) 1981-10-21 1981-10-21 Sett for polysulfidbehandling av lignocellulosamaterial vid alkalisk massaframstellning
SE8106203 1981-10-21

Publications (2)

Publication Number Publication Date
EP0091457A1 true EP0091457A1 (de) 1983-10-19
EP0091457B1 EP0091457B1 (de) 1986-12-30

Family

ID=20344836

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82903084A Expired EP0091457B1 (de) 1981-10-21 1982-10-13 Verfahren zur polysulfidbehandlung im alkalischen pulpverfahren von lignocellulosematerial

Country Status (5)

Country Link
EP (1) EP0091457B1 (de)
AT (1) ATE24556T1 (de)
DE (1) DE3274887D1 (de)
SE (1) SE8106203L (de)
WO (1) WO1983001469A1 (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10658209B2 (en) 2015-02-06 2020-05-19 Stora Enso, OYJ Apparatus and method for component positining

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FI122841B (fi) * 2004-10-04 2012-07-31 Metso Paper Inc Menetelmä ja laitteisto selluloosamassan valmistamiseksi
US8940129B2 (en) 2010-12-30 2015-01-27 Uop Llc Process for reducing one or more insoluble solids in a black liquor

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FI40677B (de) * 1961-05-27 1968-12-31 Papirind Forskningsinst
NO123511C (de) * 1966-05-14 1976-07-22 Domtar Ltd
US3567572A (en) * 1967-09-06 1971-03-02 Pulp Paper Res Inst Polysulfide liquor impregnation of lignocellulose materials in a multistage pulping process
US3723242A (en) * 1971-04-01 1973-03-27 Union Camp Corp Oxidation of sulfide pulping liquor to form polysulfide liquor in situ
NO142408C (no) * 1972-04-11 1980-08-20 Rosenlew Ab Oy W Fremgangsmaate ved alkalisk cellulosekoking.
CA1013903A (en) * 1973-06-04 1977-07-19 Union Camp Corporation Method of pulping with polysulfide

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO8301469A1 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10658209B2 (en) 2015-02-06 2020-05-19 Stora Enso, OYJ Apparatus and method for component positining

Also Published As

Publication number Publication date
ATE24556T1 (de) 1987-01-15
SE8106203L (sv) 1983-04-22
WO1983001469A1 (en) 1983-04-28
EP0091457B1 (de) 1986-12-30
DE3274887D1 (en) 1987-02-05

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