WO2017086856A1 - Procédé permettant de chauffer une matière cellulosique à une température de cuisson complète dans des lessiveurs - Google Patents

Procédé permettant de chauffer une matière cellulosique à une température de cuisson complète dans des lessiveurs Download PDF

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Publication number
WO2017086856A1
WO2017086856A1 PCT/SE2016/051013 SE2016051013W WO2017086856A1 WO 2017086856 A1 WO2017086856 A1 WO 2017086856A1 SE 2016051013 W SE2016051013 W SE 2016051013W WO 2017086856 A1 WO2017086856 A1 WO 2017086856A1
Authority
WO
WIPO (PCT)
Prior art keywords
liquor
digester
mixed liquor
steam
heated
Prior art date
Application number
PCT/SE2016/051013
Other languages
English (en)
Inventor
Krister Olsson
Original Assignee
Valmet Ab
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 Valmet Ab filed Critical Valmet Ab
Priority to EP16866744.2A priority Critical patent/EP3377696A4/fr
Publication of WO2017086856A1 publication Critical patent/WO2017086856A1/fr

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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
    • D21C7/00—Digesters
    • D21C7/10—Heating devices
    • 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
    • D21C11/10—Concentrating spent liquor by evaporation
    • 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
    • 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
    • D21C3/24—Continuous 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
    • D21C7/00—Digesters
    • D21C7/14—Means for circulating the lye
    • 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
    • D21C11/0085—Introduction of auxiliary substances into the regenerating system in order to improve the performance of certain steps of the latter, the presence of these substances being confined to the regeneration cycle
    • D21C11/0092—Substances modifying the evaporation, combustion, or thermal decomposition processes of 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
    • D21C3/22—Other features of pulping processes

Definitions

  • the present invention relates to a method for generating steam in a digester plant of a chemical pulp mill.
  • the heating is made using a heating circulation.
  • a volume of spent hot black liquor typically at full cooking temperature of 130-180 °C.
  • the heat value in the hot black liquor volume is used initially to generate steam for steaming vessel and heat white liquor, or alternative liquid volumes charged to the cooking systems.
  • the spent hot black liquor is typically sent first to two or more flash tanks connected in series where steam fractions are produced at successively lower temperature and pressure as the liquor is flashed in stages to temperatures of approximately 95-1 10 °C. Finally the black liquor is sent to the evaporator system in the recovery island.
  • ImpBinTM a single first impregnation vessel, ImpBinTM, replacing all previous chip bins, steaming vessel and impregnation vessel.
  • ImpBinTM the chips steamed and impregnated with hot black liquor that is supplied from digester, and when added to ImpBin is allowed to flash off steam for steaming and using the residual black liquor as the impregnation liquor.
  • Different concepts have been proposed where the heating to full digester temperature is replacing the addition of clean steam into digester to usage of flash steam from black liquor. Clean condensate will thus not be lost in digester, and cooking liquors will not be diluted with clean water that increase evaporation work in the recovery operations.
  • US8512514 is disclosed a complex dual heat recovery system, using a first evaporator to generate foul steam for heating in digester top using a first extraction flow from digester, and a second heat exchanger for producing clean steam from a second extraction flow from digester.
  • US8691049 concerns a method using the CrossCircTM concept promoted by Valmet AB.
  • the CrossCirc concept is hot black liquor added directly into the transfer system in order to reduce steam consumption in digester top for reaching full cooking temperature.
  • a reboiler also used to recover residual heat value in the return liquor withdrawn in the top separator, and this reboiler is producing clean steam for chip bin steaming.
  • US8808498 is yet another system disclosed where flash steam from black liquor heats white liquor, and the flashed black liquor is used in a second heat exchanger in order to heat white liquor.
  • the inventive method may also further involve that said evaporated mixed liquor obtaining a lower dry matter content than the hot black liquor and a lower concentration of alkali than the fresh alkaline cooking liquor.
  • the inventive method may also further involve that a clean steam condensate is obtained from the indirect heating in the reboiler and this clean condensate is used as heating medium in a preheater, preheating the alkaline cooking liquor or the mixed liquor before being fed to the reboiler.
  • the inventive method may also further involve that the heated evaporated mixed liquor flow (X) is heated to a temperature above the prevailing full cooking temperature, and charged at least in part to the top of the digester (DTOP) where the heated evaporated mixed liquor generates steam as well as hot cooking liquor.
  • DTOP top of the digester
  • the inventive method may also further involve that the heated evaporated mixed liquor is heated to a temperature above the prevailing full cooking temperature, and charged at least in part to a preceding impregnation vessel (IB), preferably at end of the impregnation vessel and preferably directly ahead of transfer of the cellulosic feed material to the digester (D).
  • a preceding impregnation vessel IB
  • the impregnation vessel D
  • Fig. 2 shows a modification of the digester system in Fig 1 where the inventive steam generation system is installed;
  • the extraction position for the hot black liquor at full cooking temperature may be located anywhere in the digester, i.e. within the indicated zone A.
  • a dedicated heater used for the white liquor WL charge and the addition to digester top is conventionally made using a white liquor header distributor (not shown) that sprays the white liquor into the top.
  • handling concentrated white liquor at full cooking temperature involves increased corrosion exposure, and the heaters may be subjected to alkali corrosion even if the heater is made in stainless steel needing even better and more expensive material in the heater.
  • Fig. 2 illustrates an improvement of the Compact Cooking G2TM concept as shown in Fig. 1 , and includes a steam generation system operating according to the inventive method.
  • the inventive concept is at least a part of the hot black liquor HBL, holding full cooking temperature which in this example is 141 °C, instead sent to a reboiler Reb for further heating.
  • the hot black liquor HBL be heated in preheater HE before being charged to the reboiler, and this alternative will be more described below with reference to Fig. 3.
  • a charge of fresh alkaline cooking liquor typically white liquor but any kind of alkaline cooking liquor may be used, is charged into the hot black liquor and preferably before the preheater HE.
  • the alkaline cooking liquor holds a temperature below 1 00 °C and stored in atmospheric tanks, and hence the mixed liquor WL+HBL will reach a lower temperature at about 1 30 °C. If a preheater HE is used this temperature may be increased to about 1 34 °C before charged to the reboiler Reb.
  • the reboiler holds of volume of mixed liquor WL+HBL and a coil or piping for heating media is installed in this liquor volume, in this case the heating media is medium pressure steam STMP.
  • the heating of the mixed liquor will be done indirectly, and clean steam condensate will not be lost in the mixed liquor and dilute it.
  • the coil is supplied with medium pressure steam STMP and a condensate STc is extracted from the heating coil.
  • the heated hot black liquor is elevated to temperatures above full cooking temperature, and the heat value in this hot black liquor increases, and that without dilution of clean steam condensate.
  • both the addition of alkali and heating have positive effects on the content of dissolved hemicellulose in the black liquor, that need time, temperature and high alkali concentration in order to increase cleavage rate on end groups of the hemicellulose.
  • the cleavage effect has reached a critical order could the hemicellulose start to precipitate onto cellulose and increase yield from the cook.
  • the additional retention time in the reboiler, the heating and the alkali addition all contribute synergistically in increased cleavage rate.
  • malodorous gases in the black liquor will be reduced, such as sulfur and methylmercaptans, as they will boil off to a large extent with the black liquor steam as they have a lower boiling point.
  • malodorous gases especially methylmercaptans, has well known delignification effects improving the delignification rate in the digester.
  • First option given priority to reduce need for medium pressure steam addition to digester top involves routing the flow X to digester top at the indicated position XALTL The overheated mixed liquor will then flash off additional steam as well as supply of both alkali and black liquor to cook at full cooking temperature.
  • Options 2 and 3 for the X flow are specifically adapted for a Compact CookingTM system with an ImpBin, but option 1 may be used in any digester system operating with conventional pressurized impregnation vessels as well as using other chip pretreatment systems with dedicated chip bins and steaming vessels.
  • Option 2 may also be used in conventional 2-vessel digester systems where heating is to be obtained in first vessel.
  • Fig. 3 is disclosed an embodiment of the invention in a Compact CookingTM system with an ImpBin implemented according to the first option.
  • the basic parameters for the digester system are as follows:
  • the basic parameters for the Preheater (HE) are as follows:
  • the overheated mixed liquor WL+HBL from the reboiler holds same temperature of 155.1 °C.
  • an additional amount of steam released at a rate of 4.4 kg/s which is almost 40 % of the black liquor steam STBL rate from the reboiler, while the cooking liquor WL+HBL is charged at full cooking temperature.
  • Black liquor typically has a dry matter content exceeding that of fresh cooking liquor by at least 5-20 %, so the dilution by fresh cooking liquor improves flow characteristics trough the indirect heat exchanger and reduce scaling tendencies, that often are seen in evaporation stages as a tar like deposition in the evaporation stages, where similar increase of dry matter content of undiluted black liquor is obtained.
  • a cost reduction alternative may the entire heating of the mixed liquor, i.e. black liquor and white liquor, by obtained in the indirect heater before charging to digester, which mean that the white liquor charge to digester top needs no dedicated white liquor heater, which save investment costs for such heater, and enable downscaling of any additional white liquor heater for other charges to the process.
  • Indirect heaters for concentrated white liquor are due to working conditions, heat and alkali concentration, most expensive as they need to be made in high alloy corrosive resistant steel.
  • the total charge of alkaline cooking liquor needed for the entire cook may be charged to the reboiler, or at least 20-50 % of the total necessary charge.

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  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Paper (AREA)
  • Control Of Turbines (AREA)

Abstract

La présente invention concerne un procédé de production de vapeur dans une installation de lessiveur d'une usine de pâte chimique. Un mélange de liqueur de cuisson alcaline et de liqueur noire est chauffé avant d'être chargé dans le système de lessiveur dans un rebouilleur produisant une vapeur de liqueur noire utilisée pour chauffer la matière première cellulosique dans la partie supérieure d'un lessiveur atteignant la température de cuisson complète. Ce procédé pourrait permettre d'éviter l'addition de condensat de vapeur propre à une liqueur de cuisson, et d'éviter totalement les problèmes tels que la précipitation de lignine dans les réchauffeurs de liqueur noire ainsi que la corrosion alcaline dans les réchauffeurs de liqueur de cuisson.
PCT/SE2016/051013 2015-11-16 2016-10-18 Procédé permettant de chauffer une matière cellulosique à une température de cuisson complète dans des lessiveurs WO2017086856A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP16866744.2A EP3377696A4 (fr) 2015-11-16 2016-10-18 Procédé permettant de chauffer une matière cellulosique à une température de cuisson complète dans des lessiveurs

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE1551483A SE539449C2 (en) 2015-11-16 2015-11-16 Method for heating cellulosic material to full cooking temperature in digesters
SE1551483-9 2015-11-16

Publications (1)

Publication Number Publication Date
WO2017086856A1 true WO2017086856A1 (fr) 2017-05-26

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PCT/SE2016/051013 WO2017086856A1 (fr) 2015-11-16 2016-10-18 Procédé permettant de chauffer une matière cellulosique à une température de cuisson complète dans des lessiveurs

Country Status (3)

Country Link
EP (1) EP3377696A4 (fr)
SE (1) SE539449C2 (fr)
WO (1) WO2017086856A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE1951375A1 (en) * 2019-12-02 2021-06-03 Valmet Oy Method and arrangement for adding treatment liquors to cellulose raw material in a continuous process using down flow vessels

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1097465A (fr) * 1976-11-30 1981-03-17 James R. Prough Recuperation de l'energie emmagasinee par la lessive noire
DE3621120A1 (de) * 1985-07-02 1987-01-15 Kamyr Ab Verfahren zur behandlung von zellulosematerial in einem dampf-fluessigkeits-phasen-kocher
EP0527294A1 (fr) * 1991-08-14 1993-02-17 Kamyr, Inc. Traitement des copeaux de bois avec de la liqueur noire
JP2005256224A (ja) * 2004-03-12 2005-09-22 Daio Paper Corp 塔状ベッセル型連続蒸解釜による蒸解方法
US20100236733A1 (en) * 2009-02-09 2010-09-23 Andritz Inc. Method and system to generate steam in a digester plant of a chemical pulp mill
US8986504B1 (en) * 2013-10-25 2015-03-24 International Paper Company Digester apparatus

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4897157A (en) * 1986-07-08 1990-01-30 Kamyr, Inc. Make-up liquor and black liquor evaporating processing during pulp production
US6306252B1 (en) * 1995-04-10 2001-10-23 Andritz-Ahlstrom Inc. Heat recovery from spent digester cooking liquor
FI120547B (fi) * 2004-10-04 2009-11-30 Metso Paper Inc Alkalinen keittomenetelmä ja laitteisto massan valmistamiseksi
SE0502851L (sv) * 2005-12-21 2006-12-19 Kvaerner Pulping Tech System samt förfarande för generering av ånga i ett kokeri för tillverkning av kemisk cellulosamassa
SE530332C2 (sv) * 2006-11-07 2008-05-06 Metso Fiber Karlstad Ab Förfarande för att energieffektivt producera cellulosamassa i ett kontinuerligt kokeri
FI127386B (fi) * 2014-03-05 2018-04-30 Andritz Oy Menetelmä höyryn kehittämiseksi sellutehtaan keittämöllä

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1097465A (fr) * 1976-11-30 1981-03-17 James R. Prough Recuperation de l'energie emmagasinee par la lessive noire
DE3621120A1 (de) * 1985-07-02 1987-01-15 Kamyr Ab Verfahren zur behandlung von zellulosematerial in einem dampf-fluessigkeits-phasen-kocher
EP0527294A1 (fr) * 1991-08-14 1993-02-17 Kamyr, Inc. Traitement des copeaux de bois avec de la liqueur noire
JP2005256224A (ja) * 2004-03-12 2005-09-22 Daio Paper Corp 塔状ベッセル型連続蒸解釜による蒸解方法
US20100236733A1 (en) * 2009-02-09 2010-09-23 Andritz Inc. Method and system to generate steam in a digester plant of a chemical pulp mill
US8986504B1 (en) * 2013-10-25 2015-03-24 International Paper Company Digester apparatus

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP3377696A4 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE1951375A1 (en) * 2019-12-02 2021-06-03 Valmet Oy Method and arrangement for adding treatment liquors to cellulose raw material in a continuous process using down flow vessels
SE545465C2 (en) * 2019-12-02 2023-09-19 Valmet Oy Method and arrangement for adding treatment liquors to cellulose raw material in a continuous process using down flow vessels

Also Published As

Publication number Publication date
EP3377696A1 (fr) 2018-09-26
SE1551483A1 (en) 2017-05-17
EP3377696A4 (fr) 2019-08-21
SE539449C2 (en) 2017-09-26

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