US3362868A - Method and apparatus for oxidizing spent digestion liquors - Google Patents

Method and apparatus for oxidizing spent digestion liquors Download PDF

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Publication number
US3362868A
US3362868A US337429A US33742964A US3362868A US 3362868 A US3362868 A US 3362868A US 337429 A US337429 A US 337429A US 33742964 A US33742964 A US 33742964A US 3362868 A US3362868 A US 3362868A
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United States
Prior art keywords
liquor
digester
pressure
vessel
conduit
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Expired - Lifetime
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US337429A
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English (en)
Inventor
Backlund Ernst Ake
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Metso Fiber Karlstad AB
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Kamyr AB
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Publication date
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Publication of US3362868A publication Critical patent/US3362868A/en
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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
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S423/00—Chemistry of inorganic compounds
    • Y10S423/03—Papermaking liquor

Definitions

  • the liquor is conveyed from the digester to the separate vessel by a difference in pressures between the digester and the separate vessel, and the separate vessel is maintained at a pressure which is sufliciently high to prevent the separation of volatile gases from the liquor before the liquor has been treated with air or oxygen.
  • Apparatus is provided for the method wherein an oxidation vessel is interposed between a digester and a flash chamber.
  • the invention relates to a method for treating spent liquor which in connection with continuous cellulose digestion is separated from the digested fibrous cellulose material before the same is discharged out of the digester being held under a raised pressure, and which liquor is carried off in order to recover its contents of heat and/ or chemicals.
  • the object of the invention is to perform a corresponding oxidation of the liquor in connection with continuous cellulose digestion and in a manner involving a considerable simplification as compared with the above mentioned known method used in batchwise working digesters.
  • the essential characterizing feature of the invention consists in that the spent liquor is oxidized by air in a manner known per so while it still retains at least a portion of the overpressure prevailing in the digester.
  • the liquor may be transferred to the oxidation vessel without the use of pumps or similar, the digester pressure forcing out the liquor to the oxidation vessel held under lower pressure.
  • the rate of flow may be controlled by means of choking valves or similar.
  • the oxidation is performed immediately after the liquor has left the cellulose digester, so that the liquor reaches the oxidation vessel with a temperature which may be lowered in comparison to the digestion temperature but still lies over 100 C. and is sufficiently high for the reaction desired to take place in the oxidation vessel.
  • the plant for performing the above-mentioned method comprises a digester, in the shell of which strainers are inserted for the extraction of spent liquor from the fibre material before the same is discharged out of the digester, and the inventive feature of said plant consists in that the space behind the strainers is connected to an oxidation vessel having a pressure air supply, by means of a conduit in which the pressure merely drops, said conduit thus containing no pump or similar.
  • 11 designates an upright digester which is cylindrical over the greater part of its length and to the upper end of which a mixture of a cellulosic material, such as wood chips, and a suitable digesting liquor, such as sulphate liquor, is supplied by means of a feeding apparatus 13.
  • a discharging apparatus 15 Arranged at the lower end of the digester is a discharging apparatus 15 by means of which digested pulp is continuously discharged out of the di gester.
  • the digester content is heated in the upper part of the digester by the direct supply of steam or indirectly by heating the liquor in circulation conduits (not shown) having heat exchangers inserted therein.
  • the digester content is heated to a temperature of approximately C. and a hydraulic pressure of the order of 10 kgs./sq. cm.
  • a reaction with the digestion liquor takes place so that the fibrous material is completely digested when it reaches the level of a first strainer girdle 17 inserted into the digester shell.
  • a conduit 21 Connected to the space 19 behind said strainer girdle is a conduit 21 through which the spent liquor is discharged.
  • a second strainer girdle 23 Inserted in the digester shell imrnediately below the strainer girdle 17 is a second strainer girdle 23, and inserted in the digester shell somewhat above the lower end of the digester is a third strainer girdle 25.
  • a rotary scraping and stirring device 27 Arranged between the latter and the discharging device 15 is a rotary scraping and stirring device 27, by means of which diluting water supplied through a conduit 29 is mixed into the pulp in order to facilitate its discharge. A portion of the water supplied through the conduit 29 is forced upwards in counter-current to the pulp and serves for a preliminary wash of the same before it is discharged out of the digester. Said washing liquid mixed with liquor is let out through the strainer girdle 25 and by means of a pump 30 is pumped through a heat exchanger 31 and into a tube 33 extending along the axis of the digester and opening out centrally of the digester somewhat above the level of the strainer girdle 25.
  • the other side of the heat exchanger 31 is connected into the conduit 21 carrying off the spent liquor still maintained at digesting temperature.
  • the wash liquid By means of heat exchange between said liquor and the Wash liquid the latter is heated so that the washing in the digester between the strainer girdles 25 and 23 takes place at a temperature considerably higher than the comparatively low discharging temperature of the pulp.
  • the wash liquid with liquor mixed into the same is extracted through the strainer girdle 23 and by means of the pump 35 is carried back to the digester through a tube 37 extending along the axis of the digester and opening out at a level somewhat higher than that of the strainer girdle 17.
  • the wash liquid thus supplied displaces the undiluted spent liquor and forces the same towards and out through the strainer girdle 17 from where the spent liquor, as
  • the conduit 21 is connected to the lower end of the oxidation vessel 43 in which the volatile sulphur compounds of the spent liquor are oxidized.
  • a pressure air conduit 45 is connected to the vesesl 43, and arranged therein is a motor-driven stirring device 47 for thorough mixing of air into the liquor.
  • the upper end of the vessel 43 is connected to a tangential inlet on a blow tank 49 in which a low overpressure, e.g. 1 atm., is maintained.
  • a low overpressure e.g. 1 atm.
  • a conduit 51 Inserted in said conduit is a valve 53 controlled by a control device 55 for maintaining the desired pressure of the blow tank.
  • a conduit 57 Connected to the lower end of the blow tank is a conduit 57 leading to a plant (not shown) for recovery of the chemicals of the liquor.
  • a valve 59 which is controlled in such a manner that a desired liquor level is maintained in the blow tank.
  • the outlet of the oxidation vessel is preferably choked and controlled in such a manner that a pressure of the order of 6 to 7 kgs./sq. cm. is maintained therein.
  • a pressure of the order of 6 to 7 kgs./sq. cm. is maintained therein.
  • conduit means for conveying spent liquor under an overpressure and at a temperature over C. to an oxidation vessel
  • an oxidation vessel for treating the spent liquor with air, said oxidation vessel including means for suppling air to the vessel, and including means for maintaining the pressure within said oxidation vessel at a level which is higher than atmospheric but lower than the digesting pressure of the digester, and
  • blow tank means downstream from said oxidation vessel for receiving said liquor only after it has been treated in the oxidation vessel, said blow tank means being at a pressure which is below the pressure of said oxidation vessel.
  • a heat exchanger interposed in the flow line between said digester and said oxidation vessel, said heat exchanger being connected to said conduit means for receiving and cooling spent liquor which is being conveyed to said oxidation vessel.

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US337429A 1963-01-11 1964-01-13 Method and apparatus for oxidizing spent digestion liquors Expired - Lifetime US3362868A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE28963 1963-01-11

Publications (1)

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US3362868A true US3362868A (en) 1968-01-09

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US (1) US3362868A (fi)
DE (1) DE1517145A1 (fi)
FI (1) FI44746C (fi)
FR (1) FR1379396A (fi)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3467573A (en) * 1965-12-13 1969-09-16 Improved Machinery Inc Upflow digester containing means for separate removal of wash liquor and pulping liquor and method of pulping in said digester
US3549314A (en) * 1968-05-20 1970-12-22 Chemical Construction Corp Oxidation of black liquor
US3696929A (en) * 1970-11-27 1972-10-10 Chemical Construction Corp Apparatus for the oxidation of liquids
US3969184A (en) * 1971-06-04 1976-07-13 Defibrator Ab Digestion odor control
US4058433A (en) * 1975-03-06 1977-11-15 Gulf States Paper Corporation Conversion of sulfur in blank liquor to eliminate odorous emissions and facilitate the collection of sulfate soaps
US4212705A (en) * 1978-05-22 1980-07-15 Babington William M Jr Apparatus for recovering high pressure steam from a blow tank
US4239589A (en) * 1978-10-02 1980-12-16 Air Products And Chemicals, Inc. Process for oxidation of black liquor
US4242177A (en) * 1976-04-07 1980-12-30 Mitsubishi Paper Mills, Ltd. Method for oxidizing malodorous sulfur compounds in kraft cooking liquor
US4551198A (en) * 1982-03-30 1985-11-05 Kamyr, Inc. Method of flashing black liquor
WO1999004088A1 (en) * 1997-07-14 1999-01-28 Quantum Technologies, Inc. Method of oxidizing white and black liquor
US9127403B2 (en) 2013-05-28 2015-09-08 Andritz Inc. Flash tank with flared inlet insert and method for introducing flow into a flash tank
CN107889511A (zh) * 2015-05-13 2018-04-06 艾库伊金属有限公司 用于回收铅酸电池的闭环式***和方法
US20210095420A1 (en) * 2018-05-03 2021-04-01 Valmet Ab System for treatment of a biomass material

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2726927A (en) * 1939-08-28 1955-12-13 Bt Metoder Ab Process of treating waste sulfate liquor
US2876098A (en) * 1956-01-11 1959-03-03 Hans Werner Meyer Process of and apparatus for the continuous manufacture of cellulose or hemicellulose from cellulosic fibrous materials
US3200032A (en) * 1961-12-23 1965-08-10 Kamyr Ab Continuous process for digesting cellulosic material

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2726927A (en) * 1939-08-28 1955-12-13 Bt Metoder Ab Process of treating waste sulfate liquor
US2876098A (en) * 1956-01-11 1959-03-03 Hans Werner Meyer Process of and apparatus for the continuous manufacture of cellulose or hemicellulose from cellulosic fibrous materials
US3200032A (en) * 1961-12-23 1965-08-10 Kamyr Ab Continuous process for digesting cellulosic material

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3467573A (en) * 1965-12-13 1969-09-16 Improved Machinery Inc Upflow digester containing means for separate removal of wash liquor and pulping liquor and method of pulping in said digester
US3549314A (en) * 1968-05-20 1970-12-22 Chemical Construction Corp Oxidation of black liquor
US3696929A (en) * 1970-11-27 1972-10-10 Chemical Construction Corp Apparatus for the oxidation of liquids
US3969184A (en) * 1971-06-04 1976-07-13 Defibrator Ab Digestion odor control
US4058433A (en) * 1975-03-06 1977-11-15 Gulf States Paper Corporation Conversion of sulfur in blank liquor to eliminate odorous emissions and facilitate the collection of sulfate soaps
US4242177A (en) * 1976-04-07 1980-12-30 Mitsubishi Paper Mills, Ltd. Method for oxidizing malodorous sulfur compounds in kraft cooking liquor
US4212705A (en) * 1978-05-22 1980-07-15 Babington William M Jr Apparatus for recovering high pressure steam from a blow tank
US4239589A (en) * 1978-10-02 1980-12-16 Air Products And Chemicals, Inc. Process for oxidation of black liquor
US4551198A (en) * 1982-03-30 1985-11-05 Kamyr, Inc. Method of flashing black liquor
WO1999004088A1 (en) * 1997-07-14 1999-01-28 Quantum Technologies, Inc. Method of oxidizing white and black liquor
US9127403B2 (en) 2013-05-28 2015-09-08 Andritz Inc. Flash tank with flared inlet insert and method for introducing flow into a flash tank
US9284684B2 (en) 2013-05-28 2016-03-15 Andritz Inc. Flared inlet insert for introducing flow into a flash tank
RU2634893C2 (ru) * 2013-05-28 2017-11-07 Андритц Инк. Выпарной резервуар с развальцованной впускной вставкой
CN107889511A (zh) * 2015-05-13 2018-04-06 艾库伊金属有限公司 用于回收铅酸电池的闭环式***和方法
US20210095420A1 (en) * 2018-05-03 2021-04-01 Valmet Ab System for treatment of a biomass material

Also Published As

Publication number Publication date
FR1379396A (fr) 1964-11-20
FI44746C (fi) 1971-12-10
DE1517145A1 (de) 1969-08-28
FI44746B (fi) 1971-08-31

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