Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
  • D21C3/00—Pulping cellulose-containing materials
  • D21C3/22—Other features of pulping processes
  • D21C3/222—Use of compounds accelerating the pulping processes
• • 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
  • D21C11/00—Regeneration of pulp liquors or effluent waste waters
  • D21C11/12—Combustion of pulp liquors
  • D21C11/14—Wet combustion ; Treatment of pulp liquors without previous evaporation, by oxidation of the liquors remaining at least partially in the liquid phase, e.g. by application or pressure
• • 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
  • D21C3/003—Pulping cellulose-containing materials with organic compounds
• • 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

Definitions

• the invention relates to a method for producing pulp with which it is possible to use pulp from the types of wood such as hardwoods and conifers as well as from annual plants and the cooking chemicals present in the black liquor recycle.
• Organosolv processes also include the Digestion with organic carboxylic acids, such as formic acid and acetic acid. (Buchholtz and Jordan 1983. Nimz and Casten, 1986). The corrosive ones are problematic Evaluate properties of cooking chemicals. As a cooking chemical recovery process for the Wet oxidation has already become a powerful process proposed (F.J. Zimmermann, D.G. Diddams, Tappi, August 1960, vol. 43, No.8).
• Anthraquinone is used as a catalyst for delignification viewed.
• the advantages of this addition are that further delignification of wood, which the Bleaching process made easier.
• the disadvantage of the anthraquinone additive is that it no useful recovery process for anthraquinone gives.
• hydrothropic salts in the alkaline cooking liquor will increase the solubility of the Anthraquinons increases and the effect on the Delignification intensified.
• the advantage of this process is that the whole process sulfide and sulfite ions free and thus can be carried out odorless, the existing ones Installations like those for the power-cooking process be used, can be reused.
• the elaborate reducing black liquor combustion with Energy recovery is replaced by wet oxidation, which results in a significant reduction in investment.
• the sodium hydroxide solution bound to the oxidizing substances is used in inorganic sodium bicarbonate and carbonate implemented. This partial oxidation takes place in aqueous Phase with air, oxygen or mixtures of these two, under pressure and at an elevated temperature.
• This wet oxidation can be in continuous or discontinuous operation in a reactor strong mixing, at pressures from 20 to 300 bar and at temperatures from 120 ° C to 350 ° C, with the introduction of the Oxidizing agent run for 5 to 60 minutes will.
• the liquid treated by partial wet oxidation, which comes from the reactor contains in addition to the Sodium carbonates and bicarbonates are still the hydrothropes Salts, the sodium salts of carboxylic acids, especially the Solid acetic acid and anthraquinone, which by Filtration is separated.
• This solution can be transferred to after heating Bicarbonates in carbonates, by caustification with Calcium oxide in sodium hydroxide solution of the carboxylic acids, in particular of acetic acid in addition to the hydrothropic salts Convey calcium carbonate precipitation.
• This partial oxidation in the aqueous phase also sets in free substantial amount of thermal energy which for the concentration of the cooking liquor, but also for the cooking process itself can be used.
• This lignin is then available as a further sales product Available.
• This precipitation of lignin can also be done with acetic acid take place, which has the advantage that you have lower pH values and thus can achieve more complete precipitation. Becomes If lignin is precipitated with acetic acid, it is beneficial before Submit wet oxidation caustic soda so that after the Wet oxidation of the pH of the solution is 7-8.
• Fir wood chips without bark were brought in an autoclave with four times the amount of cooking liquor in an oil bath to an internal temperature of 170 ° C. for 60 minutes and kept at this temperature for 120 minutes. After cooling to 40 ° C, the autoclave was opened and the black liquor decanted.
• the composition of the cooking and black liquors are given in Table I. Chemicals are stated in% by weight of the dry wood used.
• the fibrous portion was washed with hot water and fed to the analytics.
• the kappa number of the pulp obtained was 28 be determined.
• the mixture of Fitrat and wash water was the Oxidation reactor fed. After a temperature of 280 ° C and a pressure of 200 bar was reached Oxidation by blowing air for 10 minutes carried out. The energy released by the oxidation allowed the volume of liquid to evaporate reduce approximately half the volume of the black liquor.
• the residual solution was added to the sodium acetate corresponding amount of sodium hydroxide solution and recycling of the Anthraquinones adjusted to the appropriate concentration and fed back into the cooking process.
• the White liquor Before it is returned to the cooking process, the White liquor to a solids content of 38.5% thickened. By cooling to 20 ° C, 340g crystallize Sodium acetate trihydrate per kg dry wood. Of the Mother liquor becomes one corresponding to the isolated acetate Sodium hydroxide solution added, then after the Concentration returned to the cooking process. Of the Total alkali loss without the isolated sodium acetate take into account is 5%.
• Beech wood chips without bark were in an autoclave with five times the amount of cooking liquor poured the following composition 18% by weight NaOH, 20% by weight toluenesulfonic acid sodium salt Wood covered and which after several cycles adjusting sodium acetate concentration.
• the resulting Washed pulp After cooling and decanting, the resulting Washed pulp with hot water.
• the pulp yield was 52% by weight based on wood.
• the Kappa number could be determined at 22, the DP was included 1800.
• the black liquor was gassed with CO 2 and the majority of the lignin was precipitated, filtered and washed. 12% by weight of lignin, based on wood, were obtained.
• the mixture of Fitrat and wash water Lignin filtration was carried out at 220 ° C and a pressure of 180 bar of wet oxidation by blowing in oxygen subjected for 15 minutes.
• the volume of liquid could be reduced by the Energy to 80% of the volume before mixing with Lignin wash water can be reduced.
• the residual solution had the following composition: 16.5% by weight NaOH, 18.5% by weight toluenesulfonic acid sodium salt, 3.5% by weight Sodium acetate, calculated on dry wood.
• Wheat straw strawberries are mixed with cooking liquor in a ratio of 1: 5 poured over dry matter and during 100 Minutes kept at 170 ° C.
• the pulp yield after washing and classifying the Fiber was 45% based on dry matter.
• the one at Classifying waste, approx. 5% is the Black liquor added, which is associated with the wet oxidation Air at 280 ° C, 200 bar and 7 minutes is subjected. Filtration of the oxidized green liquor Anthraquinone with small amounts of inorganic substance recovered. After the reconstruction, the white liquor Concentrated to 38.5% solid and by cooling to 20 ° C, 360 g dry per kg of wheat straw Sodium acetate trihydrate isolated. This salt can find use outside the cooking process, and a the amount of sodium hydroxide equivalent to the isolated sodium acetate should be added during recycling in the cooking process.
• the chemical loss per cooking process is 5%.

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• Chemical & Material Sciences (AREA)
• Inorganic Chemistry (AREA)
• Paper (AREA)
• Polysaccharides And Polysaccharide Derivatives (AREA)
• Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Processes Of Treating Macromolecular Substances (AREA)

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Publications (2)

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• 1992
  • 1992-05-05 CH CH01434/92A patent/CH686682A5/de not_active IP Right Cessation
• 1993
  • 1993-04-30 NZ NZ251963A patent/NZ251963A/en unknown
  • 1993-04-30 EP EP93911418A patent/EP0593743B1/de not_active Expired - Lifetime
  • 1993-04-30 BR BR9305510A patent/BR9305510A/pt not_active IP Right Cessation
  • 1993-04-30 DE DE59307986T patent/DE59307986D1/de not_active Expired - Fee Related
  • 1993-04-30 CA CA002112802A patent/CA2112802C/en not_active Expired - Fee Related
  • 1993-04-30 ES ES93911418T patent/ES2114607T3/es not_active Expired - Lifetime
  • 1993-04-30 DK DK93911418T patent/DK0593743T3/da active
  • 1993-04-30 WO PCT/CH1993/000108 patent/WO1993022492A1/de not_active Ceased
  • 1993-04-30 US US08/170,364 patent/US5595628A/en not_active Expired - Fee Related
  • 1993-04-30 AU AU40381/93A patent/AU663784B2/en not_active Ceased
  • 1993-04-30 AT AT93911418T patent/ATE162245T1/de not_active IP Right Cessation
  • 1993-04-30 JP JP5518811A patent/JP2709192B2/ja not_active Expired - Lifetime
• 1994
  • 1994-01-03 FI FI940013A patent/FI115845B/fi active IP Right Grant

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