WO2020204783A1 - Procédé et agencement dans un procédé de production de pâte à papier en continu - Google Patents

Procédé et agencement dans un procédé de production de pâte à papier en continu Download PDF

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Publication number
WO2020204783A1
WO2020204783A1 PCT/SE2020/050285 SE2020050285W WO2020204783A1 WO 2020204783 A1 WO2020204783 A1 WO 2020204783A1 SE 2020050285 W SE2020050285 W SE 2020050285W WO 2020204783 A1 WO2020204783 A1 WO 2020204783A1
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WO
WIPO (PCT)
Prior art keywords
hydrolysate
prehydrolysis vessel
prehydrolysis
vessel
content
Prior art date
Application number
PCT/SE2020/050285
Other languages
English (en)
Inventor
Lari Lammi
Magnus Hägglund
Hunphrey LANDMAN
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 CN202080025300.9A priority Critical patent/CN113646481B/zh
Priority to EP20782621.5A priority patent/EP3947808A4/fr
Priority to BR112021013052-7A priority patent/BR112021013052A2/pt
Publication of WO2020204783A1 publication Critical patent/WO2020204783A1/fr
Priority to ZA2021/04457A priority patent/ZA202104457B/en

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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
    • 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
    • D21C1/00—Pretreatment of the finely-divided materials before digesting
    • 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
    • D21C1/00—Pretreatment of the finely-divided materials before digesting
    • D21C1/02—Pretreatment of the finely-divided materials before digesting with water or steam
    • 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
    • D21C1/00—Pretreatment of the finely-divided materials before digesting
    • D21C1/04—Pretreatment of the finely-divided materials before digesting with acid reacting 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
    • D21C11/00—Regeneration of pulp liquors or effluent waste waters
    • D21C11/0007—Recovery of by-products, i.e. compounds other than those necessary for pulping, for multiple uses or not otherwise provided for
    • 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
    • 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
    • D21C7/08—Discharge 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
    • D21C7/00—Digesters
    • D21C7/12—Devices for regulating or controlling
    • C—CHEMISTRY; METALLURGY
    • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
    • C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
    • C12P2201/00—Pretreatment of cellulosic or lignocellulosic material for subsequent enzymatic treatment or hydrolysis

Definitions

  • the present invention relates to a method for extracting hydrolysate in a continuous cooking process for producing pulp. It furthermore relates to a prehydrolysis vessel system and to a hydrolysate extracting arrangement in a continuous cooking system for producing pulp.
  • a lignocellulose raw material is first subject to a hydrolysis before an alkaline cooking is performed.
  • the hydrolysis is normally performed by adding steam or liquid to the lignocellulose raw material.
  • the hemicellulose mainly C5 sugars, are degraded and released from the wood. If the sugars should be extracted a hydrolysate comprising the dissolved sugars needs to be removed from a vessel where the hydrolysis is performed before the pH is changed and an alkaline cooking is performed.
  • the dissolved sugars after the hydrolysis are broken-down to non-valuable components.
  • Hydrolysate may be problematic due to its very sticky consistence and tendency to create scaling for example in pipes, screens and on tank surfaces.
  • Hydrolysate can be removed through screens provided in the prehydrolysis vessel in a continuous cooking system.
  • the sticky consistence of the hydrolysate and its tendency to create scaling there will be problems with scaling in the screens.
  • the screens need to be cleaned and the production efficiency may be decreased. In the worst case the production even needs to be stopped during cleaning. Any need for cleaning and any interruption in production processes are of course negative.
  • An object of the present invention is to improve production efficiency in a continuous pulp production process.
  • a further object of the present invention is to improve hydrolysate extraction efficiency in a continuous pulp production system.
  • a method for extracting hydrolysate in a continuous cooking process for producing pulp comprising the steps of: cooling a content in a prehydrolysis vessel of a continuous pulp production system such that the content has been cooled down when the content arrives at a hydrolysis outlet of the prehydrolysis vessel on its way from an inlet provided in one end of the prehydrolysis vessel to an outlet provided in an opposite end of the prehydrolysis vessel;
  • a prehydrolysis vessel system in a continuous pulp production system comprising:
  • a prehydrolysis vessel comprising:
  • hydrolysate extracting arrangement connected to the prehydrolysis vessel, said hydrolysate extracting arrangement comprising:
  • a hydrolysate removing conduit comprising a prehydrolysis vessel connector which is connected to the hydrolysate outlet of the prehydrolysis vessel; and at least one cooling device which is provided to the prehydrolysis vessel such that it can cool down a content of the prehydrolysis vessel such that the content has been cooled down when the content arrives at the hydrolysis outlet of the prehydrolysis vessel on its way from the inlet of the prehydrolysis vessel to the outlet of the prehydrolysis vessel, wherein said cooling device is configured for cooling down the content in the prehydrolysis vessel to such a degree that a hydrolysate removed through the hydrolysate outlet has a temperature between 70 °C and 130 °C.
  • a hydrolysate extracting arrangement configured for being connected to and extracting hydrolysate from a prehydrolysis vessel in a continuous pulp production system
  • said hydrolysate extracting arrangement comprising: a hydrolysate removing conduit comprising a prehydrolysis vessel connector which is arranged for being connected to a hydrolysate outlet of the prehydrolysis vessel; and
  • At least one cooling device configured such that it can be provided to the prehydrolysis vessel and such that it can cool down a content of the prehydrolysis vessel such that the content has been cooled down when the content arrives at a hydrolysis outlet of the prehydrolysis vessel on its way from an inlet provided in one end of the prehydrolysis vessel to an outlet provided in an opposite end of the prehydrolysis vessel, wherein said cooling device is configured to cool down the content in the prehydrolysis vessel to such a degree that a hydrolysate removed through the hydrolysate outlet has a temperature between 70 °C and 130 °C.
  • said prehydrolysis vessel comprises a cooling section where said cooling is performed, which cooling section is a length section of the prehydrolysis vessel, in which length section the hydrolysis outlet is provided and which length section is less than 1/3 or less than 1/5 of a total length of the prehydrolysis vessel and wherein said cooling section is closer to the outlet than to the inlet of the prehydrolysis vessel.
  • said cooling of a content in the prehydrolysis vessel comprises cooling the content to such a degree that the removed hydrolysate has a temperature between 70 °C and 120 °C or between 90 °C and 110 °C.
  • the cooling device is configured to cool the content to such a degree that the removed hydrolysate has a temperature between 70 °C and 120 °C or between 90 °C and 110° C.
  • said cooling comprises adding liquid with a temperature between 20 °C and 100 °C or a temperature between 30 °C and 80 °C or a temperature between 40 °C and 70 °C to the content in the prehydrolysis vessel.
  • the cooling device comprises a liquid adding device which is configured to add a liquid having a temperature between 20 °C and 100 °C or a temperature between 30 °C and 80 °C, or a temperature between 40 °C and 70 °C to the content of the prehydrolysis vessel.
  • said cooling comprises circulating a part of the removed hydrolysate through a heat exchanger (41) for cooling it down to a temperature between 20°C and 100 °C or a temperature between 30 °C and 80 °C or a temperature between 40 °C and 70 °C and adding the cooled hydrolysate to the content of the prehydrolysis vessel.
  • the cooling device comprises a hydrolysate circulation arrangement which is configured to circulate a part of the hydrolysate removed through the hydrolysate removing conduit through a heat exchanger for cooling it down to a temperature between 20 °C and 100 °C or a temperature between 30 °C and 80 °C or a temperature between 40 °C and 70 °C and add the cooled hydrolysate to the content of the prehydrolysis vessel.
  • said cooled hydrolysate is added into the prehydrolysis vessel through nozzles provided around a periphery of an enclosing wall of the prehydrolysis vessel.
  • At least a part of said cooled hydrolysate is added to the content of the prehydrolysis vessel through an outlet of a liquid adding pipe protruding into the prehydrolysis vessel, wherein said outlet is positioned closer to a central axis (A) of the prehydrolysis vessel than to an enclosing wall.
  • the step of removing a hydrolysate comprises removing the hydrolysate through at least one screen provided in an enclosing wall of the prehydrolysis vessel, wherein said at least one screen is the hydrolysate outlet.
  • the step of removing a hydrolysate comprises displacing the hydrolysate out through the hydrolysate outlet by adding a liquid into the prehydrolysis vessel from a bottom part of the prehydrolysis vessel.
  • the method further comprises the step of extracting sugar from the removed hydrolysate.
  • the continuous cooking process is a process for producing dissolving pulp.
  • Figures la- Id are schematic illustrations of different embodiments of prehydrolysis vessel systems comprising a hydrolysate extracting arrangement connected to a prehydrolysis vessel in a continuous cooking system according to the invention.
  • Figure 2 is a flow chart of a method for extracting hydrolysate according to one embodiment of the invention.
  • Figures la- Id are schematic illustrations of different embodiments of prehydrolysis vessel systems la, lb, lc, Id comprising a hydrolysate extracting arrangement 3a, 3b, 3c, 3d connected to a prehydrolysis vessel 5a, 5b, 5c, 5d in a continuous cooking system according to the invention. Some of the components are the same in all embodiments and will also be given the same or corresponding reference numbers.
  • the hydrolysate extracting arrangement 3a; 3b; 3c; 3d comprises a hydrolysate removing conduit 7 comprising a prehydrolysis vessel connector 8 which is arranged for being connected to a hydrolysate outlet 9 of the prehydrolysis vessel 5a; 5b; 5c; 5d.
  • the hydrolysate outlet 9 can for example be one or more screens provided in an enclosing wall 21 of the prehydrolysis vessel.
  • a reason for removing hydrolysate from the prehydrolysis vessel can be that the hydrolysate can be used in some way, for example for extraction of sugar.
  • Such a prehydrolysis vessel is a pressurized vessel.
  • the continuous cooking process of the invention can be a process for producing dissolving pulp.
  • the hydrolysate extracting arrangement 3a; 3b; 3c; 3d comprises furthermore at least one cooling device 11a, 1 lb; 1 lb’; 11c, l ie’, 11c”; l id configured such that it can be provided to the prehydrolysis vessel 5a; 5b; 5c; 5d and such that it can cool down a content of the prehydrolysis vessel such that the content has been cooled down when the content arrives at the hydrolysis outlet 9 of the prehydrolysis vessel on its way from an inlet 13 provided in one end of the prehydrolysis vessel 5a; 5b; 5c; 5d to an outlet 15 provided in an opposite end of the prehydrolysis vessel.
  • a scraper 16 is often provided in the bottom part of the prehydrolysis vessel.
  • the cooling device 11a, l ib; l ib’; 11c, l ie’, 11c”; l id is configured to cool down the content in the prehydrolysis vessel to such a degree that a hydrolysate removed through the hydrolysate outlet 9 has a temperature less than 130 °C. For example, a temperature between 70 °C and 130 °C.
  • the cooling device 11a, 1 lb; 1 lb’; 11c, l ie’, 11c”; l id is configured for cooling down the content in the prehydrolysis vessel to such a degree that a hydrolysate removed through the hydrolysate outlet 9 has a temperature less than 120 °C or between 70 °C and 120 °C and in another embodiment the cooling device 11a, l ib; l ib’; 11c, l ie’, 11c”; l id is configured for cooling down the content in the prehydrolysis vessel to such a degree that a hydrolysate removed through the hydrolysate outlet 9 has a temperature less than 110 °C or between 90 °C and 110 °C.
  • the hydrolysate outlet 9 can be provided in the enclosing wall 21 of the prehydrolysis vessel somewhere between the inlet 13 and the outlet 15 of the prehydrolysis vessel and can as mentioned above suitably be one or more screens provided in the enclosing wall.
  • the hydrolysate outlet 9 can be provided closer to the outlet 15 than the inlet 13 of the prehydrolysis vessel.
  • a normal temperature of the content in the prehydrolysis vessel 5a; 5b; 5c; 5d (i.e. before the cooling according to the invention) can for example be around 160-180°C.
  • the hydrolysate is very sticky and difficult to handle.
  • heavy scaling is easily produced in components such as tank walls, tubes and screens coming into contact with the hydrolysate.
  • the sticky consistence of the hydrolysate and its tendency to provide scaling is probably due to furfural which is produced from the dissolved sugars and also due to lignin.
  • the furfural production is a function of time, i.e. longer exposure time of sugars in such conditions leads to higher furfural concentration in the solution.
  • Lignin content also increases during the hydrolysis time. Scaling consists much of lignin and furfural together with sugars. Surprisingly it has been found that by cooling down the hydrolysate to for example less than around 130 °C or less than 120 °C or less than 110 °C the sticky consistence and tendency to provide scaling is greatly decreased and extraction of hydrolysis from a pulp production process can be much improved. Hereby also extraction of sugars from a hydrolysate can be improved.
  • the positive effect of the cooling i.e. the reduction of scaling, is surprisingly high also for relatively small temperature reductions.
  • said at least one cooling device 11a, l ib; l ib’; 11c, l ie’, 11c”; l id is configured such that it can provide a cooling effect to a content in the prehydrolysis vessel 5a; 5b; 5c; 5d in a cooling section 23 of said prehydrolysis vessel when the cooling device is provided to the prehydrolysis vessel.
  • the cooling section 23 is a length section of the prehydrolysis vessel, in which length section the hydrolysis outlet 9 is provided.
  • Said length section is in one embodiment of the invention less than 1/3 of a total length of the prehydrolysis vessel and in one embodiment less than 1/5 of a total length of the prehydrolysis vessel.
  • Said cooling section 23 is positioned closer to the outlet 15 than to the inlet 13 of the prehydrolysis vessel.
  • the cooling of the content in the prehydrolysis vessel 5a; 5b; 5c; 5d is suitably performed in the vicinity of the hydrolysate outlet 9, i.e. above, below or in level with the hydrolysate outlet 9.
  • the cooling section 23 can be defined as a length section of the prehydrolysis vessel which length section comprises a part of the enclosing wall 21 and the space inside the enclosing wall 21 within this length section.
  • the hydrolysis outlet 9 is positioned within this length section.
  • the cooling is performed somewhere within this cooling section 23 and hereby the cooling is performed in vicinity of the hydrolysate outlet 9, i.e. above, below or in level with the hydrolysate outlet 9.
  • the cooling can be performed in a number of different ways and the cooling device can be embodied in a number of different ways which will be further described in relation to Figures la- Id. These different cooling methods can also be combined in different ways which are all covered by this invention.
  • the removing of a hydrolysate from the prehydrolysis vessel 5a; 5b; 5c; 5d according to the invention can comprise displacing the hydrolysate out through the hydrolysate outlet 9 by adding a liquid into the prehydrolysis vessel from a bottom part 25 of the prehydrolysis vessel. Therefore said prehydrolysis vessel 5a; 5b; 5c; 5d can comprise a liquid adding device 27 which is configured for adding liquid to the bottom part 25 of the prehydrolysis vessel for displacing cooled hydrolysate out through the hydrolysate outlet 9.
  • the liquid that is added can be for example cooking liquor, such as white or black liquor and it can be added from nozzles in the enclosing wall 21 in the bottom part 25 and/or from a central tube 27’ provided into the vessel through a bottom 26 of the vessel as shown in Figures la- Id.
  • a liquid adding device 27 is normally provided in this type of prehydrolysis vessel for allowing transfer of the material out through the outlet 15 of the prehydrolysis vessel.
  • the central tube 27’ of the liquid adding device 27 is provided according to the invention for providing the further effect of displacing the cooled hydrolysate out through the hydrolysate outlet 9.
  • the hydrolysate extracting arrangement 3a; 3b; 3c; 3d can in some embodiments further comprise a sugar extracting arrangement 31 (only shown in Figure la, but it can be provided in all embodiments of the invention).
  • the sugar extracting arrangement is connected to the hydrolysate removing conduit 7 and is arranged for extracting sugar from the hydrolysate.
  • Sugar extraction will be more effective compared to in prior art because of the lower temperature of the hydrolysate.
  • Sugar degradation reaction is reduced in the hydrolysate thanks to the lower temperature of the hydrolysate and a total sugar yield can hereby be improved.
  • FIG. la shows one embodiment of a prehydrolysis vessel system la according to the invention.
  • a hydrolysate extracting arrangement 3a which is connected to the prehydrolysis vessel 5a comprises in this embodiment a hydrolysate removing conduit 7 and a cooling device 11a.
  • the cooling device 11a is in this embodiment a liquid adding device which is configured for adding a liquid having a temperature between 20 °C and 100 °C or a temperature between 30 °C and 80 °C or a temperature between 40°C and 70 °C to the content of the prehydrolysis vessel 5a.
  • the liquid can be for example water or washing liquid or another liquid and should be provided to the prehydrolysis vessel 5a inside the cooling section 23.
  • the liquid can suitably have a pH around 7 or can be slightly acid or slightly alkaline.
  • a liquid adding pipe 33a is provided to the prehydrolysis vessel 5a. Said liquid adding pipe 33a is protruding into the prehydrolysis vessel 5a and has an outlet 34a positioned within the cooling section 23 and suitably closer to a central axis A of the prehydrolysis vessel than an enclosing wall 21 of the prehydrolysis vessel, i.e. centered within the prehydrolysis vessel 5a in vicinity of the hydrolysate outlet 9, i.e. above, below or in level with the hydrolysate outlet 9.
  • the cooling device 11a of the hydrolysate extracting arrangement 3a can therefore be connected to the liquid adding pipe 33 for providing a liquid into the prehydrolysis vessel for cooling the content of the prehydrolysis vessel.
  • the content inside the prehydrolysis vessel 5a can be cooled down in vicinity of the hydrolysate outlet 9 (i.e. the content is cooled down above, below or in level with the hydrolysate outlet 9) and a hydrolysate removed through the hydrolysate outlet 9 can have a lower temperature than without this cooling.
  • FIG. lb shows another embodiment of a prehydrolysis vessel system lb according to the invention.
  • a hydrolysate extracting arrangement 3b which is connected to a prehydrolysis vessel 5b comprises in this embodiment a hydrolysate removing conduit 7 and a cooling device 1 lb, 1 lb’.
  • the cooling device comprises in this embodiment two parts.
  • a first part 1 lb can be connected to a liquid adding pipe 33b provided to the prehydrolysis vessel 5b.
  • Said liquid adding pipe 33b is protruding into the prehydrolysis vessel 5b and has an outlet 34b positioned within the cooling section 23 and suitably closer to a central axis A of the prehydrolysis vessel than an enclosing wall 21 of the prehydrolysis vessel, i.e. centered within the prehydrolysis vessel 5b in vicinity of the hydrolysate outlet 9, i.e. above, below or in level with the hydrolysate outlet 9.
  • the second part l ib’ of the cooling device is in this embodiment configured for adding a cooling liquid into the prehydrolysis vessel 5b through nozzles 37 provided around a periphery of an enclosing wall 21 of the prehydrolysis vessel 5b.
  • Said nozzles 37 are provided within the cooling section 23 of the prehydrolysis vessel 5b, i.e. in vicinity of the hydrolysate outlet 9, e.g. above, below or in level with the hydrolysate outlet 9.
  • a cooling liquid can be both added into the prehydrolysis vessel 5b from the enclosing wall 21 and be added to the content in the prehydrolysis vessel from a central place within the prehydrolysis vessel in vicinity of the hydrolysate outlet 9, i.e. above, below or in level with the hydrolysate outlet 9.
  • Said nozzles 37 can be provided such that they direct a cooling liquid into the prehydrolysis vessel.
  • Nozzles 37’ can however also be provided within an outer compartment 38 which is provided outside the prehydrolysis vessel such that it surrounds the screen 9 (the prehydrolysis outlet) provided in the enclosing wall 21 of the prehydrolysis vessel.
  • cooling liquid can be added to the hydrolysate when it has been removed out from the prehydrolysis vessel through the screen 9 and when the hydrolysate is provided in said outer compartment 38.
  • the hydrolysate extracting arrangement 3b comprises further a hydrolysate circulation arrangement 39.
  • the hydrolysate circulation arrangement 39 is configured for circulating a part of the hydrolysate removed through the hydrolysate removing conduit 7 through a heat exchanger 41 for cooling it down to a temperature between 20 °C and 100 °C or a temperature between 30 °C and 80 °C or a temperature between 40 °C and 70 °C and adding the cooled hydrolysate to the content of the prehydrolysis vessel 5b through the first and/or the second part l ib, l ib’ of the cooling device.
  • the cooling device may comprise only one of the first and second parts l ib, l ib’.
  • the hydrolysate circulation arrangement 39 hereby connects the hydrolysate removing conduit 7 with the first and/or second parts l ib, l ib’ of the cooling device through a heat exchanger 41 and transfers a part of the removed hydrolysate from the hydrolysate removing conduit 7, through the heat exchanger 41 and to the cooling device l ib, l ib’ for adding it to the cooling section 23 of the prehydrolysis vessel 5b when the hydrolysate extracting arrangement 3b is connected to the prehydrolysis vessel 5b.
  • the cooling provided by the heat exchanger 41 to the circulated hydrolysate can be controlled in dependence of a measured temperature of the removed hydrolysate. As discussed above a temperature of the removed hydrolysate should be controlled to be less than 130 °C or less than 120 °C or less than 110 °C.
  • Recirculation of the hydrolysate may be advantageous because no additional liquid from outside the system need to be added into the prehydrolysis vessel for providing the cooling and hereby unnecessary dilution of the hydrolysate is avoided.
  • it may be suitable to add some extra liquid as shown in the embodiment in Figure la.
  • hydrolysis extraction yield may be improved by the addition of some extra liquid.
  • It may be suitable to have a system where both these alternatives can be utilized in combination or independently. One such system is shown in Figure lc.
  • FIG. lc shows another embodiment of a prehydrolysis vessel system lc according to the invention.
  • a hydrolysate extracting arrangement 3c which is connected to a prehydrolysis vessel 5c comprises in this embodiment a hydrolysate removing conduit 7 and a cooling device 11c, l ie’, 11c”.
  • the cooling device comprises in this embodiment three parts, whereof a first part 11c and a second part l ie’ are identical to the first and second parts l ib, 1 lb’ as described above in relation to Figure lb and will not be described in detail again.
  • the first and second part 11c, l ie’ are hereby connected to a hydrolysate circulation arrangement 39 and to a liquid adding pipe 33b and to nozzles 37 as described above.
  • the third part 11c” is identical to the cooling device 11a as described in relation to Figure la and will not be described in detail.
  • the third part 11c” of the cooling device is connected to a liquid adding pipe 33a and can add a cooling liquid to the content of the prehydrolysis vessel 5c.
  • these three alternative ways of cooling the content in the prehydrolysis vessel 5c can be combined for an optimal cooling effect.
  • an operator of the system can choose one or more of the separate parts 11c, l ie’, 11c” of the cooling device for cooling the content.
  • the temperature of the added liquid can be controlled such that the removed hydrolysate has a suitable temperature such that scaling is minimized.
  • FIG. Id shows another embodiment of a prehydrolysis vessel system Id according to the invention.
  • a hydrolysate extracting arrangement 3d which is connected to a prehydrolysis vessel 5d comprises in this embodiment a hydrolysate removing conduit 7 and a cooling device l id. It comprises furthermore a hydrolysate circulation arrangement 39 as described above in relation to Figure lb.
  • the hydrolysate circulation arrangement 39 is configured for circulating a part of the hydrolysate removed through the hydrolysate removing conduit 7 through a heat exchanger 41 for cooling it down to a temperature between 20 °C and 100 °C or a temperature between 30 °C and 80 °C or a temperature between 40 °C and 70 °C and adding the cooled hydrolysate to the content of the prehydrolysis vessel 5d through the cooling device l id.
  • the cooling device l id transfers the cooled circulated hydrolysate to a number of nozzles 37.
  • the nozzles 37 are in this embodiment distributed not only around the periphery of the enclosing wall 21 but also distributed along the length of the prehydrolysis vessel 5b within the cooling section 23.
  • the prehydrolysis vessel 5d comprises a number of screens 51 which are provided in sections and nozzles 37 are provided in between said screens 51.
  • the cooled hydrolysate can be more effectively distributed over the screens and prevent scaling in the screens.
  • the prehydrolysis vessel system Id according to this embodiment can also be provided with another cooling device 11a which is adding another cooling liquid as described in relation to Figure la.
  • Figure 2 is a flow chart of the method for extracting hydrolysate in a continuous cooking process for producing pulp according to one embodiment of the invention. The steps are described in order below:
  • Said cooling is suitably performed in a cooling section of said prehydrolysis vessel, which cooling section is a length section of the prehydrolysis vessel, in which length section the hydrolysis outlet is provided
  • Said length section is in one embodiment of the invention less than 1/3 of a total length of the prehydrolysis vessel and in one embodiment less than 1/5 of a total length of the prehydrolysis vessel.
  • Said cooling section is closer to the outlet than to the inlet of the prehydrolysis vessel.
  • the cooling can be provided by adding liquid with a temperature between 20 °C and 100 °C or a temperature between 30 °C and 80 °C, or a temperature between 40 °C and 70 °C to the content in the prehydrolysis vessel.
  • the liquid can be for example water or washing liquid or circulated hydrolysate as described above.
  • S2 Removing a hydrolysate of said content through the hydrolysate outlet of the prehydrolysis vessel.
  • Said content in the prehydrolysis vessel is cooled to such a degree that the removed hydrolysate has a temperature less than 130 °C or less than 120 °C or less than 110 °C as described above. This can also be described as in interval between 70 °C and 130 °C or 120 °C or 110 °C.
  • the method can optionally also comprise a further step:

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  • Polysaccharides And Polysaccharide Derivatives (AREA)

Abstract

L'invention concerne un procédé et un agencement d'extraction d'hydrolysat dans un procédé de cuisson en continu pour la production de pâte à papier, ledit procédé comprenant les étapes consistant à : (e) refroidir un contenu dans une cuve de préhydrolyse (5a ; 5b ; 5c ; 5d) d'un système de production de pâte à papier en continu de telle sorte que le contenu ait été refroidi lorsqu'il arrive à une sortie d'hydrolyse (9) de la cuve de préhydrolyse (5a ; 5b ; 5c ; 5d) en provenance d'une entrée (13) disposée dans une extrémité de la cuve de préhydrolyse jusqu'à une sortie (15) disposée dans une extrémité opposée de la cuve de préhydrolyse ; (f) éliminer un hydrolysat dudit contenu par le biais de la sortie d'hydrolysat (9) de la cuve de préhydrolyse, ledit contenu de la cuve de préhydrolyse étant refroidi jusqu'à ce que l'hydrolysat retiré ait atteint une température comprise entre 70 °C et 130 °C.
PCT/SE2020/050285 2019-03-29 2020-03-18 Procédé et agencement dans un procédé de production de pâte à papier en continu WO2020204783A1 (fr)

Priority Applications (4)

Application Number Priority Date Filing Date Title
CN202080025300.9A CN113646481B (zh) 2019-03-29 2020-03-18 连续浆生产工艺中的方法和布置
EP20782621.5A EP3947808A4 (fr) 2019-03-29 2020-03-18 Procédé et agencement dans un procédé de production de pâte à papier en continu
BR112021013052-7A BR112021013052A2 (pt) 2019-03-29 2020-03-18 Método para extrair hidrolisado em um processo de cozimento contínuo para produzir polpa, sistema de vaso de pré-hidrólise em um sistema de produção de polpa contínuo, disposição de extração de hidrolisado
ZA2021/04457A ZA202104457B (en) 2019-03-29 2021-06-28 A method and arrangement in a continuous pulp production process

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE1950386-1 2019-03-29
SE1950386A SE1950386A1 (en) 2019-03-29 2019-03-29 A method and a system for extracting hydrolyzate in a continuous cooking process for producing pulp

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WO2020204783A1 true WO2020204783A1 (fr) 2020-10-08

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EP (1) EP3947808A4 (fr)
CN (1) CN113646481B (fr)
BR (1) BR112021013052A2 (fr)
SE (1) SE1950386A1 (fr)
WO (1) WO2020204783A1 (fr)
ZA (1) ZA202104457B (fr)

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US3530034A (en) 1969-05-16 1970-09-22 Itt Rayonier Inc Continuous aqueous prehydrolysis of wood chips
CA1189005A (fr) * 1982-01-22 1985-06-18 Carl L. Elmore Traitement par hydrolyse en milieu acide et extraction a la soude caustique
US20080295981A1 (en) 2007-05-23 2008-12-04 Andritz Inc. Single vessel reactor system for hydrolysis and digestion of wood chips with chemical enhanced wash method
US20090318679A1 (en) 2008-06-10 2009-12-24 Andritz Inc. Apparatus and method for hydrolysis of cellulosic material in a two-step process
WO2012158075A1 (fr) * 2011-05-13 2012-11-22 Metso Paper Sweden Ab Procédé compact d'obtention de pâte préalablement hydrolysée
US20140246158A1 (en) 2007-05-23 2014-09-04 Andritz Inc. Two vessel reactor system and method for hydrolysis and digestion of wood chips with chemical enhanced wash method

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BRPI0505212A (pt) * 2005-11-01 2007-08-07 Dedini Sa Ind De Base aperfeiçoamentos em processo de hidrólise ácida rápida de material lignocelulósico e em reator de hidrólise
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RU2509833C2 (ru) * 2007-11-01 2014-03-20 О-Вирон Инкорпорейтед Способ и устройство для гидролиза целлюлозного материала
JP5378306B2 (ja) * 2010-06-15 2013-12-25 月島機械株式会社 バイオマスの処理装置及び処理方法
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Publication number Priority date Publication date Assignee Title
US3530034A (en) 1969-05-16 1970-09-22 Itt Rayonier Inc Continuous aqueous prehydrolysis of wood chips
CA1189005A (fr) * 1982-01-22 1985-06-18 Carl L. Elmore Traitement par hydrolyse en milieu acide et extraction a la soude caustique
US20080295981A1 (en) 2007-05-23 2008-12-04 Andritz Inc. Single vessel reactor system for hydrolysis and digestion of wood chips with chemical enhanced wash method
US20140246158A1 (en) 2007-05-23 2014-09-04 Andritz Inc. Two vessel reactor system and method for hydrolysis and digestion of wood chips with chemical enhanced wash method
US20090318679A1 (en) 2008-06-10 2009-12-24 Andritz Inc. Apparatus and method for hydrolysis of cellulosic material in a two-step process
WO2012158075A1 (fr) * 2011-05-13 2012-11-22 Metso Paper Sweden Ab Procédé compact d'obtention de pâte préalablement hydrolysée

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Title
See also references of EP3947808A4

Also Published As

Publication number Publication date
EP3947808A4 (fr) 2022-12-28
ZA202104457B (en) 2023-01-25
SE542991C2 (en) 2020-09-22
CN113646481A (zh) 2021-11-12
SE1950386A1 (en) 2020-09-22
EP3947808A1 (fr) 2022-02-09
BR112021013052A2 (pt) 2021-10-26
CN113646481B (zh) 2022-11-22

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