[go: up one dir, main page]

EP3580388A1 - System and method for silica removal in a pulping process - Google Patents

System and method for silica removal in a pulping process

Info

Publication number
EP3580388A1
EP3580388A1 EP18750677.9A EP18750677A EP3580388A1 EP 3580388 A1 EP3580388 A1 EP 3580388A1 EP 18750677 A EP18750677 A EP 18750677A EP 3580388 A1 EP3580388 A1 EP 3580388A1
Authority
EP
European Patent Office
Prior art keywords
chip slurry
chip
fluid
silica
vessel
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
EP18750677.9A
Other languages
German (de)
French (fr)
Other versions
EP3580388A4 (en
EP3580388B1 (en
Inventor
Fredrik Wilgotson
Stefan ANTONSSON
Lars Eriksson
Bengt WERNERSSON ÖSTBERG
Krister Olsson
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.)
Valmet Technologies Oy
Valmet AB
Original Assignee
Valmet Oy
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 Oy, Valmet AB filed Critical Valmet Oy
Publication of EP3580388A1 publication Critical patent/EP3580388A1/en
Publication of EP3580388A4 publication Critical patent/EP3580388A4/en
Application granted granted Critical
Publication of EP3580388B1 publication Critical patent/EP3580388B1/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

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
    • 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
    • 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
    • D21B—FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
    • D21B1/00—Fibrous raw materials or their mechanical treatment
    • D21B1/02—Pretreatment of the raw materials by chemical or physical means
    • D21B1/023—Cleaning wood chips or other raw 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
    • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
    • D21C9/08—Removal of fats, resins, pitch or waxes; Chemical or physical purification, i.e. refining, of crude cellulose by removing non-cellulosic contaminants, optionally combined with bleaching
    • 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
    • D21C11/00—Regeneration of pulp liquors or effluent waste waters
    • D21C11/0021—Introduction of various effluents, e.g. waste waters, into the pulping, recovery and regeneration cycle (closed-cycle)

Definitions

  • the present invention relates generally to a system and a method for the removal of silica contaminants from wood chips in a prehydrolysis kraft cooking pulp production process, and in particular to a system and a method in which silica is removed from a warm chip slurry containing chips that have been soaked in fluid for an extended soaking time at an elevated temperature.
  • the system disclosed in this patent is rather complex and comprises many moving parts, which are exposed to wear. In effect, also this system is difficult to scale to match the requirements of today's large-scale pulp mills, at least in a cost-effective way.
  • An object of the present invention is therefore to provide an improved system and an improved method for removing contaminants in a pulp production process.
  • the system and the method should thereby be easy to implement in large-scale pulp production processes in a cost-effective way.
  • the system and the method should in particular be effective for removing silica, and should also be particularly suitable for use in the production of dissolving pulp.
  • a system for silica removal in a process for pulp production for example a process for the production of dissolving pulp, comprises a vessel; a chip inlet and a steam inlet, which both are arranged in a top section of the vessel; a first fluid inlet arranged below the top section and adapted for inlet of a fluid, such as water or a diluted mineral acid, e.g.
  • diluted sulphuric acid to provide a chip slurry having a specified chip slurry temperature in a chip soaking zone disposed below the top section; a chip slurry outlet arranged in a bottom section of the vessel and connected to a chip slurry transportation pipe, which extends out from the vessel for transport of the chip slurry for further processing outside of the vessel; a second fluid inlet arranged in the bottom section of the vessel for dilution of the chip slurry transported (or to be transported) in the chip slurry transportation pipe to a liquor-to-wood ratio of at least 10: 1 with a dilution fluid, such as water or a diluted mineral acid, e.g.
  • a dilution fluid such as water or a diluted mineral acid, e.g.
  • diluted sulphuric acid having a specified dilution fluid temperature that is higher than the chip slurry temperature; a dewatering device connected to the chip slurry transportation pipe for dewatering of the chip slurry transported therein and for providing a first flow of chip slurry having a liquor- to-wood ratio of less than 3 : 1 and for providing a second flow of silica-containing fluid; a return pipe connected to the dewatering device for transport of the second flow of silica- containing fluid and connected to the first fluid inlet or to the second fluid inlet; and at least one silica separator, which is arranged in the return pipe.
  • a chip soaking zone is a zone disposed below a top section of the vessel, and in which chips introduced into the vessel via the chip inlet are submerged in or covered by fluid, e.g. water or a diluted mineral acid, e.g. diluted sulphuric acid, which is introduced into the vessel via the first fluid inlet and/or the second fluid inlet.
  • fluid e.g. water or a diluted mineral acid, e.g. diluted sulphuric acid
  • the chips should dwell in this chip soaking zone for a specified soaking time of about 30 minutes to 120 minutes. Within this time interval, silica-containing contaminants, such as sand and clay, which adhere to the surfaces of the chips or which are more or less embedded in the chips, should be dissolved and released from the chips.
  • the method and the system according to the invention are particularly suited for use in an open system, i.e. the vessel containing the chip slurry, is an open, i.e. non-pressurized, vessel, which means that the temperature of the chip slurry in the soaking zone cannot be too high, to avoid excessive boiling of the chip slurry, and the chip slurry temperature should therefore preferably be about 95 °C to about 105 °C.
  • the dilution fluid temperature should be chosen such that the dilution fluid, when added to the chip slurry contained in the vessel, does not cause excessive boiling of the chip slurry, and in practice a dilution fluid temperature of about 110 °C to about 130 °C is useful.
  • the chip slurry is typically pumped out from the vessel, and the consistency of the chip slurry being transported in the chip slurry transportation pipe, or being contained in the bottom section of the vessel for transport in the chip slurry transportation pipe, should therefore allow effective pumping, whereby a liquor-to-wood ratio of at least 10: 1 is useful for the chip slurry in the chip slurry transportation pipe, i.e. the liquor-to-wood ratio of at least 10: 1 relates to the consistency of the chip slurry in the transportation pipe, where the liquor-to-wood ratio - if one so wishes - can be measured.
  • said second fluid inlet which alternatively may be referred to as a dilution fluid inlet, is not arranged in a bottom section of the vessel, but is instead arranged in the chip slurry transportation pipe.
  • said second fluid inlet is divided, such that a second fluid inlet is arranged both in a bottom section of the vessel and in the chip slurry transportation pipe.
  • the return pipe for transport of the second flow of silica containing fluid is connected to both the first fluid inlet and to the second fluid inlet.
  • a mixer can be arranged in the chip slurry transportation pipe; and to enhance the silica-separating action of said at least one silica separator, an inlet for adding an agglomerating and/or flocculating agent, such as polyacrylamide, can be arranged in the return pipe before, as seen in flow direction, the first one of said at least one silica separator.
  • an agglomerating and/or flocculating agent such as polyacrylamide
  • these silica separators can be arranged in parallel or in series; and to ensure effective heating of the dilution fluid, the return pipe can be provided with a heater, e.g. a heat exchanger.
  • FIG. 1 is a schematic illustration of a first embodiment of a system for silica removal in a pulp production process according to the present invention.
  • Fig. 2 is a schematic illustration of a second embodiment of a system for silica removal in a pulp production process according to the present invention.
  • Fig. 3 is a schematic illustration of a third embodiment of a system for silica removal in a pulp production process according to the present invention.
  • Fig. 4 is a schematic illustration of a fourth embodiment of a system for silica removal in a pulp production process according to the present invention.
  • Fig. 5 is a schematic illustration of a fifth embodiment of a system for silica removal in a pulp production process according to the present invention.
  • Fig. 6 is a schematic illustration of a sixth embodiment of a system for silica removal in a pulp production process according to the present invention.
  • Fig. 1 illustrates schematically a first embodiment of a system 1 for silica removal in a pulping process according to the present invention.
  • the silica-removal system 1 comprises at least a vessel 2, which has a top section 3 and a bottom section 4; a chip inlet 5 provided in the top section 3 for introduction of wood chips, a steam inlet 6 provided in the top section 3 for introduction of steam; a first fluid inlet 7 provided in the vessel and disposed below the top section 3 for introduction of a fluid, such as water or a diluted mineral acid, e.g. diluted sulphuric acid, coming from a fluid source 19, e.g.
  • a fluid such as water or a diluted mineral acid, e.g. diluted sulphuric acid
  • a fluid tank 19 to provide a chip slurry having a chip slurry temperature in a chip soaking zone 8, which is disposed below the top section 3, the chip soaking zone 8 being a zone in which chips are submerged in or covered by fluid for a specified soaking time; a chip slurry outlet 9 provided in the bottom section 4 and connected to a chip slurry transportation pipe 10 for transport of the chip slurry out from the vessel 2; a second fluid inlet 11 arranged in the slurry transportation pipe 10 for dilution of the chip slurry to a liquor-to-wood ratio of at least 10: 1, as measured in the chip slurry transportation pipe 10, with a dilution fluid, such as water or a diluted mineral acid, e.g.
  • a dilution fluid such as water or a diluted mineral acid, e.g.
  • diluted sulphuric acid coming from a dilution fluid source 18, e.g. a dilution fluid tank 18, and having a dilution fluid temperature that is higher than the chip slurry temperature; a dewatering device 12 connected to the chip slurry transportation pipe 10 for dewatering of the chip slurry contained therein and for providing a first flow 13 of chip slurry having a liquor-to-wood ration less than 3 : 1 and providing a second flow 14 of silica-containing fluid; a return pipe 15 connected to the dewatering device 12 for transport of the second flow 14 of silica-containing fluid and connected to the second fluid inlet 11; and at least one silica separator 16 provided in the return pipe 15.
  • a dilution fluid source e.g. a dilution fluid tank 18, and having a dilution fluid temperature that is higher than the chip slurry temperature
  • a dewatering device 12 connected to the chip slurry transportation pipe 10 for dewatering of the chip slurry
  • the soaking time for the chips in the chip soaking zone 8 is about 30 minutes to 120 minutes
  • the chip slurry temperature in the chip soaking zone 8 is about 95-105 °C
  • the dilution fluid temperature is about 1 10-130 °C.
  • a heater 17, e.g. heat exchanger 17, can be provided in the return pipe 15, to warm the dilution fluid to the specified dilution fluid temperature, if needed.
  • the heater 17 is disposed close to the dilution fluid source 18, such that the heater 17 essentially only warm up the dilution fluid coming from the dilution fluid source 18 and does not warm up the second flow 14 of silica-containing fluid.
  • a mixer 20 can be provided in the chip slurry transportation pipe 10 before - as seen in flow direction - the dewatering device 12, to ensure efficient mixing of the dilution fluid and the chip slurry.
  • the first flow 13 of chip slurry has a liquor-to-wood ratio of at least 3 : 1.
  • This rather low value i.e. a relatively large amount of wood in relation to fluid, indicates that the dewatering device is effective and that the first flow 13 contains a relatively small amount of silica.
  • a low value also implies that the chip slurry contains a relatively small amount of fluid that has to be heated in following processing steps. Such processing steps are not part of the present invention, but should nevertheless be considered when designing an efficient system for silica removal.
  • Dewatering devices that are suitable for use in all embodiments presented herein are the dewatering devices manufactured and marketed by the company Valmet AB, for example the top separators marketed by Valmet AB.
  • a second embodiment of a system 1 for silica removal according to the invention is schematically illustrated.
  • the silica-removal system 1 comprises at least a vessel 2, which has a top section 3 and a bottom section 4; a chip inlet 5 provided in the top section 3 for introduction of wood chips, a steam inlet 6 provided in the top section 3 for introduction of steam; a first fluid inlet 7 provided in the vessel and disposed below the top section 3 for introduction of a fluid, such as water or a diluted mineral acid, e.g.
  • diluted sulphuric acid coming from a fluid source 19, e.g. a fluid tank 19, to provide a chip slurry having a chip slurry temperature in a chip soaking zone 8, which is disposed below the top section 3, the chip soaking zone 8 being a zone in which chips are submerged in or covered by fluid for a specified soaking time; a chip slurry outlet 9 provided in the bottom section 4 and connected to a chip slurry transportation pipe 10 for transport of the chip slurry out from the vessel 2; a second fluid inlet 11 arranged in the bottom section 4 for dilution of the chip slurry to a liquor-to-wood ratio of at least 10: 1, as measured in the chip slurry transportation pipe 10, with a dilution fluid, such as water or a diluted mineral acid, e.g.
  • a dilution fluid such as water or a diluted mineral acid, e.g.
  • diluted sulphuric acid coming from a dilution fluid source 18, e.g. a dilution fluid tank 18, and having a dilution fluid temperature that is higher than the chip slurry temperature; a dewatering device 12 connected to the chip slurry transportation pipe 10 for dewatering of the chip slurry contained therein and for providing a first flow 13 of chip slurry having a liquor-to-wood ration less than 3 : 1 and providing a second flow 14 of silica-containing fluid; a return pipe 15 connected to the dewatering device 12 for transport of the second flow 14 of silica-containing fluid and connected to the second fluid inlet 11; and at least one silica separator 16 provided in the return pipe 15.
  • a dilution fluid source e.g. a dilution fluid tank 18, and having a dilution fluid temperature that is higher than the chip slurry temperature
  • a dewatering device 12 connected to the chip slurry transportation pipe 10 for dewatering of the chip slurry
  • the soaking time for the chips in the chip soaking zone 8 is about 30 minutes to 120 minutes
  • the chip slurry temperature in the chip soaking zone 8 is about 95-150 °C
  • the dilution fluid temperature is about 1 10-130 °C.
  • a heater 17, e.g. heat exchanger 17, can be provided in the return pipe 15, to warm the dilution fluid to the specified dilution fluid temperature, if needed.
  • the heater 17 is disposed in a position such that the heater 17 warm up both the dilution fluid coming from the dilution fluid source 18 and also the second flow 14 of silica-containing fluid.
  • a mixer 20 can be provided in the chip slurry transportation pipe 10 before - as seen in flow direction - the dewatering device 12, to ensure efficient mixing of the dilution fluid and the chip slurry.
  • Fig. 3 illustrates schematically a third embodiment of a system 1 for silica removal in a pulping process according to the present invention.
  • the silica-removal system 1 comprises at least a vessel 2, which has a top section 3 and a bottom section 4; a chip inlet 5 provided in the top section 3 for introduction of wood chips, a steam inlet 6 provided in the top section 3 for introduction of steam; a first fluid inlet 7 provided in the vessel and disposed below the top section 3 for introduction of a fluid, such as water or a diluted mineral acid, e.g. diluted sulphuric acid, coming from a fluid source 19, e.g.
  • a fluid such as water or a diluted mineral acid, e.g. diluted sulphuric acid
  • a fluid tank 19 to provide a chip slurry having a chip slurry temperature in a chip soaking zone 8, which is disposed below the top section 3, the chip soaking zone 8 being a zone in which chips are submerged in or covered by fluid for a specified soaking time; a chip slurry outlet 9 provided in the bottom section 4 and connected to a chip slurry transportation pipe 10 for transport of the chip slurry out from the vessel 2; a second fluid inlet 11 arranged in the slurry transportation pipe 10 for dilution of the chip slurry to a liquor-to-wood ratio of at least 10: 1, as measured in the chip slurry transportation pipe 10, with a dilution fluid having a dilution fluid temperature that is higher than the chip slurry temperature; a dewatering device 12 connected to the chip slurry transportation pipe 10 for dewatering of the chip slurry contained therein and for providing a first flow 13 of chip slurry having a liquor-to-wood ration less than 3 : 1 and providing a second flow
  • the soaking time for the chips in the chip soaking zone 8 is about 30 minutes to 120 minutes
  • the chip slurry temperature in the chip soaking zone 8 is about 95-105 °C
  • the dilution fluid temperature is about 110-130 °C.
  • a heater 17, e.g. heat exchanger 17 can be provided in the return pipe 15, to warm the dilution fluid to the specified dilution fluid temperature, if needed.
  • a mixer 20 can be provided in the chip slurry transportation pipe 10 before - as seen in flow direction - the dewatering device 12, to ensure efficient mixing of the dilution fluid and the chip slurry.
  • Fig. 4 illustrates schematically a fourth embodiment of a system 1 for silica removal in a pulping process according to the present invention.
  • the silica-removal system 1 comprises at least a vessel 2, which has a top section 3 and a bottom section 4; a chip inlet 5 provided in the top section 3 for introduction of wood chips, a steam inlet 6 provided in the top section 3 for introduction of steam; a first fluid inlet 7 provided in the vessel and disposed below the top section 3 for introduction of a fluid, such as water or a diluted mineral acid, e.g. diluted sulphuric acid, coming from a fluid source 19, e.g.
  • a fluid such as water or a diluted mineral acid, e.g. diluted sulphuric acid
  • a fluid tank 19 to provide a chip slurry having a chip slurry temperature in a chip soaking zone 8, which is disposed below the top section 3, the chip soaking zone 8 being a zone in which chips are submerged in or covered by fluid for a specified soaking time;
  • a chip slurry outlet 9 provided in the bottom section 4 and connected to a chip slurry transportation pipe 10 for transport of the chip slurry out from the vessel 2;
  • a dewatering device 12 connected to the chip slurry transportation pipe 10 for dewatering of the chip slurry contained therein and for providing a first flow 13 of chip slurry having a liquor-to-wood ration less than 3 : 1 and providing a
  • the soaking time for the chips in the chip soaking zone 8 is about 30 minutes to 120 minutes
  • the chip slurry temperature in the chip soaking zone 8 is about 95-105 °C
  • the dilution fluid temperature is about 110-130 °C.
  • a heater 17, e.g. heat exchanger 17 can be provided in the return pipe 15, to warm the dilution fluid to the specified dilution fluid temperature, if needed.
  • a mixer 20 can be provided in the chip slurry transportation pipe 10 before - as seen in flow direction - the dewatering device 12, to ensure efficient mixing of the dilution fluid and the chip slurry.
  • a fifth embodiment of a system 1 for silica removal according to the invention is schematically illustrated.
  • the silica-removal system 1 comprises at least a vessel 2, which has a top section 3 and a bottom section 4; a chip inlet 5 provided in the top section 3 for introduction of wood chips, a steam inlet 6 provided in the top section 3 for introduction of steam; a first fluid inlet 7 provided in the vessel and disposed below the top section 3 for introduction of a fluid, such as water or a diluted mineral acid, e.g.
  • diluted sulphuric acid coming from a fluid source 19, e.g. a fluid tank 19, to provide a chip slurry having a chip slurry temperature in a chip soaking zone 8, which is disposed below the top section 3, the chip soaking zone 8 being a zone in which chips are submerged in or covered by fluid for a specified soaking time; a chip slurry outlet 9 provided in the bottom section 4 and connected to a chip slurry transportation pipe 10 for transport of the chip slurry out from the vessel 2; a second fluid inlet 11 arranged in the chip slurry transportation pipe 10 for dilution of the chip slurry to a liquor-to-wood ratio of at least 10: 1, as measured in the chip slurry transportation pipe 10, with a dilution fluid, such as water or a diluted mineral acid, e.g.
  • a dilution fluid such as water or a diluted mineral acid, e.g.
  • diluted sulphuric acid coming from a dilution fluid source 18, e.g. a dilution fluid tank 18, and having a dilution fluid temperature that is higher than the chip slurry temperature; a dewatering device 12 connected to the chip slurry transportation pipe 10 for dewatering of the chip slurry contained therein and for providing a first flow 13 of chip slurry having a liquor-to-wood ration less than 3 : 1 and providing a second flow 14 of silica-containing fluid; a return pipe 15 connected to the dewatering device 12 for transport of the second flow 14 of silica-containing fluid and connected to the first fluid inlet 7; and at least one silica separator 16 provided in the return pipe 15.
  • a dilution fluid source e.g. a dilution fluid tank 18, and having a dilution fluid temperature that is higher than the chip slurry temperature
  • a dewatering device 12 connected to the chip slurry transportation pipe 10 for dewatering of the chip slurry
  • the soaking time for the chips in the chip soaking zone 8 is about 30 minutes to 120 minutes
  • the chip slurry temperature in the chip soaking zone 8 is about 95-150 °C
  • the dilution fluid temperature is about 1 10-130 °C.
  • a heater 17, e.g. heat exchanger 17 can be provided before the second fluid inlet 1 1, to warm the dilution fluid coming from the dilution fluid source 18 to the specified dilution fluid temperature, if needed.
  • a mixer 20 can be provided in the chip slurry transportation pipe 10 before - as seen in flow direction - the dewatering device 12, to ensure efficient mixing of the dilution fluid and the chip slurry.
  • a sixth embodiment of a system 1 for silica removal according to the invention is schematically illustrated.
  • the silica-removal system 1 comprises at least a vessel 2, which has a top section 3 and a bottom section 4; a chip inlet 5 provided in the top section 3 for introduction of wood chips, a steam inlet 6 provided in the top section 3 for introduction of steam; a first fluid inlet 7 provided in the vessel and disposed below the top section 3 for introduction of a fluid, such as water or a diluted mineral acid, e.g.
  • diluted sulphuric acid to provide a chip slurry having a chip slurry temperature in a chip soaking zone 8, which is disposed below the top section 3, the chip soaking zone 8 being a zone in which chips are submerged in or covered by fluid for a specified soaking time; a chip slurry outlet 9 provided in the bottom section 4 and connected to a chip slurry transportation pipe 10 for transport of the chip slurry out from the vessel 2; a second fluid inlet 1 1 arranged in the bottom section 4 for dilution of the chip slurry to a liquor-to-wood ratio of at least 10: 1, as measured in the chip slurry transportation pipe 10, with a dilution fluid, such as water or a diluted mineral acid, e.g.
  • a dilution fluid such as water or a diluted mineral acid, e.g.
  • diluted sulphuric acid coming from a dilution fluid source 18, e.g. a dilution fluid tank 18, and having a dilution fluid temperature that is higher than the chip slurry temperature; a dewatering device 12 connected to the chip slurry transportation pipe 10 for dewatering of the chip slurry contained therein and for providing a first flow 13 of chip slurry having a liquor-to-wood ration less than 3 : 1 and providing a second flow 14 of silica-containing fluid; a return pipe 15 connected to the dewatering device 12 for transport of the second flow 14 of silica-containing fluid and connected to the first fluid inlet 7; and at least one silica separator 16 provided in the return pipe 15.
  • a dilution fluid source e.g. a dilution fluid tank 18, and having a dilution fluid temperature that is higher than the chip slurry temperature
  • a dewatering device 12 connected to the chip slurry transportation pipe 10 for dewatering of the chip slurry
  • the soaking time for the chips in the chip soaking zone 8 is about 30 minutes to 120 minutes
  • the chip slurry temperature in the chip soaking zone 8 is about 95-105 °C
  • the dilution fluid temperature is about 110-130 °C.
  • a heater 17, e.g. heat exchanger 17 can be provided before the second fluid inlet 11 to warm the dilution fluid coming from the dilution fluid source 18 to the specified dilution fluid temperature, if needed.
  • a mixer 20 can be provided in the chip slurry transportation pipe 10 before - as seen in flow direction - the dewatering device 12, to ensure efficient mixing of the dilution fluid and the chip slurry.
  • a return pipe in both a first fluid inlet and a second fluid inlet, which is connected to a bottom section of a vessel and/or connected to a chip slurry transportation pipe.
  • an inlet for adding an agglomerating and/or flocculating agent, such as polyacrylamide, can be arranged in the return pipe 15 before, as seen in flow direction, the first one of said at least one silica separator 16.
  • Such an agglomerating agent can enhance the efficiency of the silica separator.
  • the common feature for all embodiments presented herein is that the efficiency of the silica removal is enhanced by soaking the chips for a predetermined chip soaking time at rather high, specified temperature.

Landscapes

  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Wood Science & Technology (AREA)
  • Mechanical Engineering (AREA)
  • Paper (AREA)
  • Silicon Compounds (AREA)

Abstract

The invention relates generally to a system and a method for the removal of silica contaminants from wood chips in a prehydrolysis kraft cooking pulp production process, and in particular to a system and a method in which silica is removed from a warm chip slurry containing chips that have been soaked in fluid for an extended soaking time at an elevated temperature.

Description

SYSTEM AND METHOD FOR SILICA REMOVAL IN A PULPING PROCESS
TECHNICAL FIELD
The present invention relates generally to a system and a method for the removal of silica contaminants from wood chips in a prehydrolysis kraft cooking pulp production process, and in particular to a system and a method in which silica is removed from a warm chip slurry containing chips that have been soaked in fluid for an extended soaking time at an elevated temperature.
BACKGROUND
In many systems and methods for producing pulp from lignocellulosic material, contaminations in the form of, for example, sand and clay particles impose a problem. When producing dissolving pulp, where the end customer typically requires a high chemical purity, there is a problem with clogging of nozzles and other production equipment in, for example, viscose processes, due to high silica content if sand and clay particles are not removed from the dissolving pulp.
Many systems for the production of pulp therefore comprise systems and apparatuses for chip washing. For example, the U.S. Patent No. 5,882,509 to Perman discloses a system for treating and recycling wash water, wherein the system comprises a settling tank, a circulation tank, and a hydrocyclone. This system is space consuming, and is therefore difficult to adapt to modern, large-scale pulp production processes. Furthermore, the particle separation appears to be rather incomplete. The U.S. Patent No. 9,333,468 to Nguyen et al. describes a soak vessel for impregnating biomass with a liquid, such as a dilute acid, and for removing contaminants, wherein the soak vessel comprises an impeller assembly, which, in turn, comprises no less than three individual impellers which perform different functions. Thus, the system disclosed in this patent is rather complex and comprises many moving parts, which are exposed to wear. In effect, also this system is difficult to scale to match the requirements of today's large-scale pulp mills, at least in a cost-effective way. An object of the present invention is therefore to provide an improved system and an improved method for removing contaminants in a pulp production process. The system and the method should thereby be easy to implement in large-scale pulp production processes in a cost-effective way. The system and the method should in particular be effective for removing silica, and should also be particularly suitable for use in the production of dissolving pulp.
SUMMARY OF THE INVENTION The above-mentioned objects are achieved with a system and a method according to the independent claims. Preferred embodiments are set forth in the dependent claims.
According to one embodiment of the present invention, a system for silica removal in a process for pulp production, for example a process for the production of dissolving pulp, comprises a vessel; a chip inlet and a steam inlet, which both are arranged in a top section of the vessel; a first fluid inlet arranged below the top section and adapted for inlet of a fluid, such as water or a diluted mineral acid, e.g. diluted sulphuric acid, to provide a chip slurry having a specified chip slurry temperature in a chip soaking zone disposed below the top section; a chip slurry outlet arranged in a bottom section of the vessel and connected to a chip slurry transportation pipe, which extends out from the vessel for transport of the chip slurry for further processing outside of the vessel; a second fluid inlet arranged in the bottom section of the vessel for dilution of the chip slurry transported (or to be transported) in the chip slurry transportation pipe to a liquor-to-wood ratio of at least 10: 1 with a dilution fluid, such as water or a diluted mineral acid, e.g. diluted sulphuric acid, having a specified dilution fluid temperature that is higher than the chip slurry temperature; a dewatering device connected to the chip slurry transportation pipe for dewatering of the chip slurry transported therein and for providing a first flow of chip slurry having a liquor- to-wood ratio of less than 3 : 1 and for providing a second flow of silica-containing fluid; a return pipe connected to the dewatering device for transport of the second flow of silica- containing fluid and connected to the first fluid inlet or to the second fluid inlet; and at least one silica separator, which is arranged in the return pipe. As defined herein, a chip soaking zone is a zone disposed below a top section of the vessel, and in which chips introduced into the vessel via the chip inlet are submerged in or covered by fluid, e.g. water or a diluted mineral acid, e.g. diluted sulphuric acid, which is introduced into the vessel via the first fluid inlet and/or the second fluid inlet. Further, to provide an efficient removal of silica, the chips should dwell in this chip soaking zone for a specified soaking time of about 30 minutes to 120 minutes. Within this time interval, silica-containing contaminants, such as sand and clay, which adhere to the surfaces of the chips or which are more or less embedded in the chips, should be dissolved and released from the chips. Further, the method and the system according to the invention are particularly suited for use in an open system, i.e. the vessel containing the chip slurry, is an open, i.e. non-pressurized, vessel, which means that the temperature of the chip slurry in the soaking zone cannot be too high, to avoid excessive boiling of the chip slurry, and the chip slurry temperature should therefore preferably be about 95 °C to about 105 °C. Furthermore, the dilution fluid temperature should be chosen such that the dilution fluid, when added to the chip slurry contained in the vessel, does not cause excessive boiling of the chip slurry, and in practice a dilution fluid temperature of about 110 °C to about 130 °C is useful.
As can be appreciated, the chip slurry is typically pumped out from the vessel, and the consistency of the chip slurry being transported in the chip slurry transportation pipe, or being contained in the bottom section of the vessel for transport in the chip slurry transportation pipe, should therefore allow effective pumping, whereby a liquor-to-wood ratio of at least 10: 1 is useful for the chip slurry in the chip slurry transportation pipe, i.e. the liquor-to-wood ratio of at least 10: 1 relates to the consistency of the chip slurry in the transportation pipe, where the liquor-to-wood ratio - if one so wishes - can be measured.
In another embodiment of the present invention, said second fluid inlet, which alternatively may be referred to as a dilution fluid inlet, is not arranged in a bottom section of the vessel, but is instead arranged in the chip slurry transportation pipe. In still another embodiment, said second fluid inlet is divided, such that a second fluid inlet is arranged both in a bottom section of the vessel and in the chip slurry transportation pipe. Similarly, in embodiments of the invention, the return pipe for transport of the second flow of silica containing fluid is connected to both the first fluid inlet and to the second fluid inlet. To ensure effective mixing of the chip slurry and the dilution fluid, a mixer can be arranged in the chip slurry transportation pipe; and to enhance the silica-separating action of said at least one silica separator, an inlet for adding an agglomerating and/or flocculating agent, such as polyacrylamide, can be arranged in the return pipe before, as seen in flow direction, the first one of said at least one silica separator. Moreover, if more than one silica separator is provided, these silica separators can be arranged in parallel or in series; and to ensure effective heating of the dilution fluid, the return pipe can be provided with a heater, e.g. a heat exchanger.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be further explained hereinafter by means of non-limiting examples and with reference to the appended drawings, wherein: Fig. 1 is a schematic illustration of a first embodiment of a system for silica removal in a pulp production process according to the present invention.
Fig. 2 is a schematic illustration of a second embodiment of a system for silica removal in a pulp production process according to the present invention.
Fig. 3 is a schematic illustration of a third embodiment of a system for silica removal in a pulp production process according to the present invention.
Fig. 4 is a schematic illustration of a fourth embodiment of a system for silica removal in a pulp production process according to the present invention.
Fig. 5 is a schematic illustration of a fifth embodiment of a system for silica removal in a pulp production process according to the present invention. Fig. 6 is a schematic illustration of a sixth embodiment of a system for silica removal in a pulp production process according to the present invention. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
For all embodiments presented below and illustrated in the figures, corresponding parts and components have been given the same reference numerals.
Fig. 1 illustrates schematically a first embodiment of a system 1 for silica removal in a pulping process according to the present invention. The silica-removal system 1 comprises at least a vessel 2, which has a top section 3 and a bottom section 4; a chip inlet 5 provided in the top section 3 for introduction of wood chips, a steam inlet 6 provided in the top section 3 for introduction of steam; a first fluid inlet 7 provided in the vessel and disposed below the top section 3 for introduction of a fluid, such as water or a diluted mineral acid, e.g. diluted sulphuric acid, coming from a fluid source 19, e.g. a fluid tank 19, to provide a chip slurry having a chip slurry temperature in a chip soaking zone 8, which is disposed below the top section 3, the chip soaking zone 8 being a zone in which chips are submerged in or covered by fluid for a specified soaking time; a chip slurry outlet 9 provided in the bottom section 4 and connected to a chip slurry transportation pipe 10 for transport of the chip slurry out from the vessel 2; a second fluid inlet 11 arranged in the slurry transportation pipe 10 for dilution of the chip slurry to a liquor-to-wood ratio of at least 10: 1, as measured in the chip slurry transportation pipe 10, with a dilution fluid, such as water or a diluted mineral acid, e.g. diluted sulphuric acid, coming from a dilution fluid source 18, e.g. a dilution fluid tank 18, and having a dilution fluid temperature that is higher than the chip slurry temperature; a dewatering device 12 connected to the chip slurry transportation pipe 10 for dewatering of the chip slurry contained therein and for providing a first flow 13 of chip slurry having a liquor-to-wood ration less than 3 : 1 and providing a second flow 14 of silica-containing fluid; a return pipe 15 connected to the dewatering device 12 for transport of the second flow 14 of silica-containing fluid and connected to the second fluid inlet 11; and at least one silica separator 16 provided in the return pipe 15. Further, in this embodiment, the soaking time for the chips in the chip soaking zone 8 is about 30 minutes to 120 minutes, the chip slurry temperature in the chip soaking zone 8 is about 95-105 °C, and the dilution fluid temperature is about 1 10-130 °C. Optionally, a heater 17, e.g. heat exchanger 17, can be provided in the return pipe 15, to warm the dilution fluid to the specified dilution fluid temperature, if needed. In the first embodiment shown in Fig. 1, the heater 17 is disposed close to the dilution fluid source 18, such that the heater 17 essentially only warm up the dilution fluid coming from the dilution fluid source 18 and does not warm up the second flow 14 of silica-containing fluid. Further, also optionally, a mixer 20 can be provided in the chip slurry transportation pipe 10 before - as seen in flow direction - the dewatering device 12, to ensure efficient mixing of the dilution fluid and the chip slurry.
As stated above, the first flow 13 of chip slurry has a liquor-to-wood ratio of at least 3 : 1. This rather low value, i.e. a relatively large amount of wood in relation to fluid, indicates that the dewatering device is effective and that the first flow 13 contains a relatively small amount of silica. A low value also implies that the chip slurry contains a relatively small amount of fluid that has to be heated in following processing steps. Such processing steps are not part of the present invention, but should nevertheless be considered when designing an efficient system for silica removal. Dewatering devices that are suitable for use in all embodiments presented herein are the dewatering devices manufactured and marketed by the company Valmet AB, for example the top separators marketed by Valmet AB. Also, the sand separators manufactured and marketed by Valmet AB are suitable for use as silica separators in all embodiments presented herein. In Fig. 2, a second embodiment of a system 1 for silica removal according to the invention is schematically illustrated. The silica-removal system 1 comprises at least a vessel 2, which has a top section 3 and a bottom section 4; a chip inlet 5 provided in the top section 3 for introduction of wood chips, a steam inlet 6 provided in the top section 3 for introduction of steam; a first fluid inlet 7 provided in the vessel and disposed below the top section 3 for introduction of a fluid, such as water or a diluted mineral acid, e.g. diluted sulphuric acid, coming from a fluid source 19, e.g. a fluid tank 19, to provide a chip slurry having a chip slurry temperature in a chip soaking zone 8, which is disposed below the top section 3, the chip soaking zone 8 being a zone in which chips are submerged in or covered by fluid for a specified soaking time; a chip slurry outlet 9 provided in the bottom section 4 and connected to a chip slurry transportation pipe 10 for transport of the chip slurry out from the vessel 2; a second fluid inlet 11 arranged in the bottom section 4 for dilution of the chip slurry to a liquor-to-wood ratio of at least 10: 1, as measured in the chip slurry transportation pipe 10, with a dilution fluid, such as water or a diluted mineral acid, e.g. diluted sulphuric acid, coming from a dilution fluid source 18, e.g. a dilution fluid tank 18, and having a dilution fluid temperature that is higher than the chip slurry temperature; a dewatering device 12 connected to the chip slurry transportation pipe 10 for dewatering of the chip slurry contained therein and for providing a first flow 13 of chip slurry having a liquor-to-wood ration less than 3 : 1 and providing a second flow 14 of silica-containing fluid; a return pipe 15 connected to the dewatering device 12 for transport of the second flow 14 of silica-containing fluid and connected to the second fluid inlet 11; and at least one silica separator 16 provided in the return pipe 15. Further, in this embodiment, the soaking time for the chips in the chip soaking zone 8 is about 30 minutes to 120 minutes, the chip slurry temperature in the chip soaking zone 8 is about 95-150 °C, and the dilution fluid temperature is about 1 10-130 °C. Optionally, a heater 17, e.g. heat exchanger 17, can be provided in the return pipe 15, to warm the dilution fluid to the specified dilution fluid temperature, if needed. In the second embodiment shown in Fig. 2, the heater 17 is disposed in a position such that the heater 17 warm up both the dilution fluid coming from the dilution fluid source 18 and also the second flow 14 of silica-containing fluid. Further, also optionally, a mixer 20 can be provided in the chip slurry transportation pipe 10 before - as seen in flow direction - the dewatering device 12, to ensure efficient mixing of the dilution fluid and the chip slurry.
Fig. 3 illustrates schematically a third embodiment of a system 1 for silica removal in a pulping process according to the present invention. The silica-removal system 1 comprises at least a vessel 2, which has a top section 3 and a bottom section 4; a chip inlet 5 provided in the top section 3 for introduction of wood chips, a steam inlet 6 provided in the top section 3 for introduction of steam; a first fluid inlet 7 provided in the vessel and disposed below the top section 3 for introduction of a fluid, such as water or a diluted mineral acid, e.g. diluted sulphuric acid, coming from a fluid source 19, e.g. a fluid tank 19, to provide a chip slurry having a chip slurry temperature in a chip soaking zone 8, which is disposed below the top section 3, the chip soaking zone 8 being a zone in which chips are submerged in or covered by fluid for a specified soaking time; a chip slurry outlet 9 provided in the bottom section 4 and connected to a chip slurry transportation pipe 10 for transport of the chip slurry out from the vessel 2; a second fluid inlet 11 arranged in the slurry transportation pipe 10 for dilution of the chip slurry to a liquor-to-wood ratio of at least 10: 1, as measured in the chip slurry transportation pipe 10, with a dilution fluid having a dilution fluid temperature that is higher than the chip slurry temperature; a dewatering device 12 connected to the chip slurry transportation pipe 10 for dewatering of the chip slurry contained therein and for providing a first flow 13 of chip slurry having a liquor-to-wood ration less than 3 : 1 and providing a second flow 14 of silica-containing fluid; a return pipe 15 connected to the dewatering device 12 for transport of the second flow 14 of silica-containing fluid and connected to the second fluid inlet 11; and at least one silica separator 16 provided in the return pipe 15. Further, in this embodiment, the soaking time for the chips in the chip soaking zone 8 is about 30 minutes to 120 minutes, the chip slurry temperature in the chip soaking zone 8 is about 95-105 °C, and the dilution fluid temperature is about 110-130 °C. As can be noted, in this embodiment, there is no extra source of dilution fluid, such as a dilution fluid source 18, which was optionally arranged in the first embodiment and the second embodiment, respectively. Optionally, a heater 17, e.g. heat exchanger 17, can be provided in the return pipe 15, to warm the dilution fluid to the specified dilution fluid temperature, if needed. Also optionally, a mixer 20 can be provided in the chip slurry transportation pipe 10 before - as seen in flow direction - the dewatering device 12, to ensure efficient mixing of the dilution fluid and the chip slurry.
Fig. 4 illustrates schematically a fourth embodiment of a system 1 for silica removal in a pulping process according to the present invention. The silica-removal system 1 comprises at least a vessel 2, which has a top section 3 and a bottom section 4; a chip inlet 5 provided in the top section 3 for introduction of wood chips, a steam inlet 6 provided in the top section 3 for introduction of steam; a first fluid inlet 7 provided in the vessel and disposed below the top section 3 for introduction of a fluid, such as water or a diluted mineral acid, e.g. diluted sulphuric acid, coming from a fluid source 19, e.g. a fluid tank 19, to provide a chip slurry having a chip slurry temperature in a chip soaking zone 8, which is disposed below the top section 3, the chip soaking zone 8 being a zone in which chips are submerged in or covered by fluid for a specified soaking time; a chip slurry outlet 9 provided in the bottom section 4 and connected to a chip slurry transportation pipe 10 for transport of the chip slurry out from the vessel 2; a second fluid inlet 11 arranged in the bottom section 4 for dilution of the chip slurry to a liquor-to-wood ratio of at least 10: 1, as measured in the chip slurry transportation pipe 10, with a dilution fluid having a dilution fluid temperature that is higher than the chip slurry temperature; a dewatering device 12 connected to the chip slurry transportation pipe 10 for dewatering of the chip slurry contained therein and for providing a first flow 13 of chip slurry having a liquor-to-wood ration less than 3 : 1 and providing a second flow 14 of silica-containing fluid; a return pipe
15 connected to the dewatering device 12 for transport of the second flow 14 of silica- containing fluid and connected to the second fluid inlet 11; and at least one silica separator
16 provided in the return pipe 15. Further, in this embodiment, the soaking time for the chips in the chip soaking zone 8 is about 30 minutes to 120 minutes, the chip slurry temperature in the chip soaking zone 8 is about 95-105 °C, and the dilution fluid temperature is about 110-130 °C. As can be noted, in this embodiment, there is no extra source of dilution fluid, such as a dilution fluid source 18, which was optionally arranged in the first embodiment and the second embodiment, respectively. Optionally, a heater 17, e.g. heat exchanger 17, can be provided in the return pipe 15, to warm the dilution fluid to the specified dilution fluid temperature, if needed. Also optionally, a mixer 20 can be provided in the chip slurry transportation pipe 10 before - as seen in flow direction - the dewatering device 12, to ensure efficient mixing of the dilution fluid and the chip slurry. In Fig. 5, a fifth embodiment of a system 1 for silica removal according to the invention is schematically illustrated. The silica-removal system 1 comprises at least a vessel 2, which has a top section 3 and a bottom section 4; a chip inlet 5 provided in the top section 3 for introduction of wood chips, a steam inlet 6 provided in the top section 3 for introduction of steam; a first fluid inlet 7 provided in the vessel and disposed below the top section 3 for introduction of a fluid, such as water or a diluted mineral acid, e.g. diluted sulphuric acid, coming from a fluid source 19, e.g. a fluid tank 19, to provide a chip slurry having a chip slurry temperature in a chip soaking zone 8, which is disposed below the top section 3, the chip soaking zone 8 being a zone in which chips are submerged in or covered by fluid for a specified soaking time; a chip slurry outlet 9 provided in the bottom section 4 and connected to a chip slurry transportation pipe 10 for transport of the chip slurry out from the vessel 2; a second fluid inlet 11 arranged in the chip slurry transportation pipe 10 for dilution of the chip slurry to a liquor-to-wood ratio of at least 10: 1, as measured in the chip slurry transportation pipe 10, with a dilution fluid, such as water or a diluted mineral acid, e.g. diluted sulphuric acid, coming from a dilution fluid source 18, e.g. a dilution fluid tank 18, and having a dilution fluid temperature that is higher than the chip slurry temperature; a dewatering device 12 connected to the chip slurry transportation pipe 10 for dewatering of the chip slurry contained therein and for providing a first flow 13 of chip slurry having a liquor-to-wood ration less than 3 : 1 and providing a second flow 14 of silica-containing fluid; a return pipe 15 connected to the dewatering device 12 for transport of the second flow 14 of silica-containing fluid and connected to the first fluid inlet 7; and at least one silica separator 16 provided in the return pipe 15. Further, in this embodiment, the soaking time for the chips in the chip soaking zone 8 is about 30 minutes to 120 minutes, the chip slurry temperature in the chip soaking zone 8 is about 95-150 °C, and the dilution fluid temperature is about 1 10-130 °C. Optionally, a heater 17, e.g. heat exchanger 17, can be provided before the second fluid inlet 1 1, to warm the dilution fluid coming from the dilution fluid source 18 to the specified dilution fluid temperature, if needed. Further, also optionally, a mixer 20 can be provided in the chip slurry transportation pipe 10 before - as seen in flow direction - the dewatering device 12, to ensure efficient mixing of the dilution fluid and the chip slurry.
In Fig. 6, a sixth embodiment of a system 1 for silica removal according to the invention is schematically illustrated. The silica-removal system 1 comprises at least a vessel 2, which has a top section 3 and a bottom section 4; a chip inlet 5 provided in the top section 3 for introduction of wood chips, a steam inlet 6 provided in the top section 3 for introduction of steam; a first fluid inlet 7 provided in the vessel and disposed below the top section 3 for introduction of a fluid, such as water or a diluted mineral acid, e.g. diluted sulphuric acid, to provide a chip slurry having a chip slurry temperature in a chip soaking zone 8, which is disposed below the top section 3, the chip soaking zone 8 being a zone in which chips are submerged in or covered by fluid for a specified soaking time; a chip slurry outlet 9 provided in the bottom section 4 and connected to a chip slurry transportation pipe 10 for transport of the chip slurry out from the vessel 2; a second fluid inlet 1 1 arranged in the bottom section 4 for dilution of the chip slurry to a liquor-to-wood ratio of at least 10: 1, as measured in the chip slurry transportation pipe 10, with a dilution fluid, such as water or a diluted mineral acid, e.g. diluted sulphuric acid, coming from a dilution fluid source 18, e.g. a dilution fluid tank 18, and having a dilution fluid temperature that is higher than the chip slurry temperature; a dewatering device 12 connected to the chip slurry transportation pipe 10 for dewatering of the chip slurry contained therein and for providing a first flow 13 of chip slurry having a liquor-to-wood ration less than 3 : 1 and providing a second flow 14 of silica-containing fluid; a return pipe 15 connected to the dewatering device 12 for transport of the second flow 14 of silica-containing fluid and connected to the first fluid inlet 7; and at least one silica separator 16 provided in the return pipe 15. Further, in this embodiment, the soaking time for the chips in the chip soaking zone 8 is about 30 minutes to 120 minutes, the chip slurry temperature in the chip soaking zone 8 is about 95-105 °C, and the dilution fluid temperature is about 110-130 °C. Optionally, a heater 17, e.g. heat exchanger 17, can be provided before the second fluid inlet 11 to warm the dilution fluid coming from the dilution fluid source 18 to the specified dilution fluid temperature, if needed. Further, also optionally, a mixer 20 can be provided in the chip slurry transportation pipe 10 before - as seen in flow direction - the dewatering device 12, to ensure efficient mixing of the dilution fluid and the chip slurry.
The embodiments described above and discussed in conjunction with the figures are only exemplifying, and many variations are possible. In particular, it is possible to combine all features of a particular embodiment with other features of other embodiments. For example, it is possible to arrange a return pipe in both a first fluid inlet and a second fluid inlet, which is connected to a bottom section of a vessel and/or connected to a chip slurry transportation pipe. Further, for all embodiments, but not shown in the figures, an inlet for adding an agglomerating and/or flocculating agent, such as polyacrylamide, can be arranged in the return pipe 15 before, as seen in flow direction, the first one of said at least one silica separator 16. Such an agglomerating agent can enhance the efficiency of the silica separator. The common feature for all embodiments presented herein is that the efficiency of the silica removal is enhanced by soaking the chips for a predetermined chip soaking time at rather high, specified temperature. Although the present invention has been described with reference to specific embodiments, also shown in the appended drawings, it will be apparent to those skilled in the art that many variations and modifications can be done within the scope of the invention as described in the specification and defined with reference to the claims below. For example, the invention has been described with reference to wood chips, but could be applicable for any lignocellulosic material, such as bamboo.

Claims

1. A system (1) for silica removal in a process for prehydrolysis kraft pulp production, the system (1) comprising at least:
a vessel (2) having a top section (3) and a bottom section (4);
a chip inlet (5) arranged in the top section (3) for introduction of wood chips into the vessel (2);
a steam inlet (6) arranged in the top section (3) for introduction of steam into the vessel (2);
a first fluid inlet (7) arranged in the vessel (2) for introduction of fluid into the vessel (2), to provide a chip slurry having a chip slurry temperature in a soaking zone (8) disposed below the top section (3), the chip soaking zone (8) being a zone in which wood chips are submerged in fluid for a specified soaking time;
a chip slurry outlet (9) arranged in the bottom section (4) and connected to a chip slurry transportation pipe (10) for transport of the chip slurry;
a second fluid inlet (1 1) arranged in the bottom section (4) and/or in the chip slurry transportation pipe (10) for dilution of the chip slurry in the chip slurry transportation pipe (10) to a liquid-to-wood ratio of at least 10: 1 with a dilution fluid having a temperature higher than the chip slurry temperature;
a dewatering device (12) connected to the chip slurry transportation pipe (10) for dewatering the chip slurry and creating a first flow (13) of chip slurry having a liquid-to-wood ratio of less than 3 : 1 and a second flow (14) of silica-containing fluid; and
a return pipe (15) connected to the dewatering device (12) for transport of the second flow (14) of silica-containing fluid and connected to the first fluid inlet (7) and/or to the second fluid inlet (1 1),
characterized in that at least one silica separator (16) is arranged in the return pipe (15), and that the system is arranged so that the soaking time is about between 30 minutes to 120 minutes, that the chip slurry temperature is about 95-105 °C, and that the dilution fluid temperature is about 1 10-130 °C.
2. The system (1) according to claim 1, characterized in that the process for pulp production is a process for dissolving pulp production.
3. The system (1) according to claim 1 or claim 2, characterized in that a mixer (20) is arranged in the chip slurry transportation pipe (15).
4. The system (1) according to any preceding claim, characterized in that an inlet for addition of an agglomerating agent is arranged in the return pipe (15).
5. A method for silica removal in a process for prehydrolysis kraft pulp production, the method comprising at least the following steps:
introducing wood chips into a vessel (2) via a chip inlet (5) arranged in a top section (3) of the vessel (2), said vessel comprising said top section (3) and a bottom section (4);
introducing steam into the vessel (2) via a steam inlet (6) arranged in the top section (3);
introducing fluid into the vessel (2) via a first fluid inlet (7) arranged in the vessel
(2), to provide a chip slurry having a chip slurry temperature in a soaking zone (8) disposed below the top section (3), the chip soaking zone (8) being a zone in which wood chips are submerged in fluid for a specified soaking time;
transporting the chip slurry out of the vessel (2) through a chip slurry outlet (9) arranged in the bottom section (4) and connected to a chip slurry transportation pipe (10);
diluting the chip slurry in the chip slurry transportation pipe (10) to a liquid-to- wood ration of at least 10: 1 with a dilution fluid having a temperature higher than the chip slurry temperature via a second fluid inlet (11) arranged in the bottom section (4) and/or in the chip slurry transportation pipe (10);
dewatering the chip slurry with a dewatering device (12) connected to the chip slurry transportation pipe (10) and creating a first flow (13) of chip slurry having a liquid-to-wood ratio of less than 3 : 1 and a second flow (14) of silica-containing fluid; and
transporting the second flow (14) of silica-containing fluid via a return pipe (15) connected to the dewatering device (12) and connected to the first fluid inlet (7) and/or to the second fluid inlet (11), characterized in that silica is removed from the silica-containing fluid by at least one silica separator (16) arranged in the return pipe (15), and that the soaking time is about between 30 minutes to 120 minutes, that the chip slurry temperature is about 95-105 °C, and that the dilution fluid temperature is about 110-130 °C.
6. The method according to claim 5, characterized in that the process for pulp production is a process for dissolving pulp production.
7. The method according to claim 5 or claim 6, characterized in that a mixer (20) is arranged in the chip slurry transportation pipe (15).
8. The method according to any preceding claims 5-7, characterized in that an inlet for addition of an agglomerating agent is arranged in the return pipe (15).
EP18750677.9A 2017-02-07 2018-01-31 System and method for silica removal in a pulping process Active EP3580388B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE1750106A SE1750106A1 (en) 2017-02-07 2017-02-07 System and method for silica removal in a pulping process
PCT/SE2018/050072 WO2018147784A1 (en) 2017-02-07 2018-01-31 System and method for silica removal in a pulping process

Publications (3)

Publication Number Publication Date
EP3580388A1 true EP3580388A1 (en) 2019-12-18
EP3580388A4 EP3580388A4 (en) 2020-12-23
EP3580388B1 EP3580388B1 (en) 2023-05-10

Family

ID=62244602

Family Applications (1)

Application Number Title Priority Date Filing Date
EP18750677.9A Active EP3580388B1 (en) 2017-02-07 2018-01-31 System and method for silica removal in a pulping process

Country Status (9)

Country Link
EP (1) EP3580388B1 (en)
CN (1) CN110249092A (en)
CL (1) CL2019002201A1 (en)
ES (1) ES2947013T3 (en)
FI (1) FI3580388T3 (en)
PL (1) PL3580388T3 (en)
PT (1) PT3580388T (en)
SE (1) SE1750106A1 (en)
WO (1) WO2018147784A1 (en)

Family Cites Families (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4199399A (en) * 1976-04-19 1980-04-22 Process Evaluation & Development Corp. Method for preparing bagasse dissolving pulps and producing rayon having a degree of polymerization of at least 800 therefrom
IN154386B (en) * 1979-12-10 1984-10-20 Dorr Oliver Inc
US4436586A (en) * 1982-01-22 1984-03-13 Kamyr, Inc. Method of producing kraft pulp using an acid prehydrolysis and pre-extraction
US4668340A (en) * 1984-03-20 1987-05-26 Kamyr, Inc. Method of countercurrent acid hydrolysis of comminuted cellulosic fibrous material
FI103418B1 (en) * 1996-01-31 1999-06-30 Sunds Defibrator Woodhandling Process and apparatus for the pre-treatment of fibrous materials for the manufacture of cellulose pulp
ZA974836B (en) * 1997-06-02 1998-06-24 Bountiful Applied Res Corp Process for treating spent, waste, alkaline digestion liquor from paper pulping operations and product.
US6332950B1 (en) * 1997-06-25 2001-12-25 Kaverner Pulping Ab Method in connection with the pretreatment of comminuted fibrous material
EP1969175B1 (en) * 2005-12-07 2012-04-11 O'Flynn, Kelly Anthony A novel catalytic reactor process for the production of commercial grade pulp, native lignin and unicellular protein
CN101255664B (en) * 2008-02-02 2010-10-20 山东太阳纸业股份有限公司 Method for pulping of non-lumber fibre
FI123100B (en) * 2010-03-11 2012-11-15 Metso Paper Inc Procedure for the collection of by-products
CA2869215A1 (en) * 2012-04-03 2013-10-10 Ovivo Luxembourg S.a.r.l. Process for removal of solid non-fibrous material from pulp
US9333468B2 (en) * 2012-09-24 2016-05-10 Abengoa Bioenergy New Technologies, Llc Soak vessels and methods for impregnating biomass with liquid
JP6522274B2 (en) * 2013-08-06 2019-05-29 日本製紙株式会社 Method of making dissolved kraft pulp.
CN203429499U (en) * 2013-09-11 2014-02-12 江苏飞翔纸业有限公司 Anti-blocking pulping waste water recycling system
US10179971B2 (en) * 2014-03-21 2019-01-15 Iogen Energy Corporation Method for processing a cellulosic feedstock at high consistency
SE539706C2 (en) * 2014-11-07 2017-11-07 Valmet Oy Method for recovering hydrolysate

Also Published As

Publication number Publication date
WO2018147784A1 (en) 2018-08-16
SE540305C2 (en) 2018-06-05
CL2019002201A1 (en) 2019-11-08
ES2947013T3 (en) 2023-07-31
FI3580388T3 (en) 2023-07-10
BR112019014396A2 (en) 2020-02-11
EP3580388A4 (en) 2020-12-23
EP3580388B1 (en) 2023-05-10
SE1750106A1 (en) 2018-06-05
CN110249092A (en) 2019-09-17
PT3580388T (en) 2023-06-05
PL3580388T3 (en) 2023-09-11

Similar Documents

Publication Publication Date Title
FI119553B (en) Process and apparatus for mass production from sawdust
CN105350368A (en) Two vessel reactor system and method for hydrolysis and digestion of wood chips with chemical enhanced wash method
EP2591165B1 (en) Method and system for impregnating chips
CN103290715A (en) Waste paper deinking process and apparatus thereof
EP3580388A1 (en) System and method for silica removal in a pulping process
RU2673311C1 (en) Cooking boiler of continuous action and power supply system
CN201648058U (en) Fine filter system for steam generator of nuclear power station
CN111819323B (en) Method for producing dissolving pulp
CN101617081A (en) The vapour phase digester and the method that are used for continuously cooking
BR112019014396B1 (en) SYSTEM AND METHOD FOR REMOVING SILICA IN A PROCESS FOR PRODUCING KRAFT PULP WITH PRE-HYDROLYSIS
CN103669066B (en) Improve the method for stickies removal effect in waste and old boxboard
Saif et al. Wastewater Minimization in Pulp and Paper Industries through Energy‐Efficient Reverse‐Osmosis Membrane Processes
CN209636028U (en) A kind of sizing Mead-Bauer recovery system
JP5220391B2 (en) Method and apparatus for bringing hot liquid directly into contact with wood chips in transfer circulation
JP2001507409A (en) Method for continuously guiding liquid when cooking pulp in a digester
CA1110411A (en) Recycling by repulping wax and resin impregnated paperboards in black liquor
US20230061371A1 (en) Method and processing system for reducing volatile organic compounds from wood chips
CN113811650B (en) Method for extracting hydrolysate, batch cooking system and hydrolysate extraction device
CN111560786A (en) Boiling separation hot-pressing equipment
CN104233893A (en) Clean high-efficiency pulp cleaning process
RU2805175C2 (en) Method for supplying wood chips into preliminary hydrolysis reactor
CN101387085A (en) Single vessel reactor system for hydrolysis and digestion of wood chips with chemical enhanced wash method
CN114008264B (en) Method for extracting hemicellulose from lignocellulose material
FI129118B (en) Method for feeding wood chips to a prehydrolysis reactor
CN108457114B (en) Papermaking process

Legal Events

Date Code Title Description
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE INTERNATIONAL PUBLICATION HAS BEEN MADE

PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE

17P Request for examination filed

Effective date: 20190705

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

AX Request for extension of the european patent

Extension state: BA ME

DAV Request for validation of the european patent (deleted)
DAX Request for extension of the european patent (deleted)
RIC1 Information provided on ipc code assigned before grant

Ipc: D21C 1/04 20060101ALI20201026BHEP

Ipc: D21C 1/02 20060101AFI20201026BHEP

Ipc: D21B 1/02 20060101ALI20201026BHEP

RIC1 Information provided on ipc code assigned before grant

Ipc: D21B 1/02 20060101ALI20201112BHEP

Ipc: D21C 1/02 20060101AFI20201112BHEP

Ipc: D21C 1/04 20060101ALI20201112BHEP

A4 Supplementary search report drawn up and despatched

Effective date: 20201119

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: GRANT OF PATENT IS INTENDED

INTG Intention to grant announced

Effective date: 20221219

GRAS Grant fee paid

Free format text: ORIGINAL CODE: EPIDOSNIGR3

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE PATENT HAS BEEN GRANTED

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

REG Reference to a national code

Ref country code: GB

Ref legal event code: FG4D

REG Reference to a national code

Ref country code: AT

Ref legal event code: REF

Ref document number: 1566781

Country of ref document: AT

Kind code of ref document: T

Effective date: 20230515

Ref country code: CH

Ref legal event code: EP

REG Reference to a national code

Ref country code: DE

Ref legal event code: R096

Ref document number: 602018049628

Country of ref document: DE

REG Reference to a national code

Ref country code: PT

Ref legal event code: SC4A

Ref document number: 3580388

Country of ref document: PT

Date of ref document: 20230605

Kind code of ref document: T

Free format text: AVAILABILITY OF NATIONAL TRANSLATION

Effective date: 20230529

REG Reference to a national code

Ref country code: IE

Ref legal event code: FG4D

P01 Opt-out of the competence of the unified patent court (upc) registered

Effective date: 20230503

REG Reference to a national code

Ref country code: FI

Ref legal event code: FGE

REG Reference to a national code

Ref country code: ES

Ref legal event code: FG2A

Ref document number: 2947013

Country of ref document: ES

Kind code of ref document: T3

Effective date: 20230731

REG Reference to a national code

Ref country code: LT

Ref legal event code: MG9D

REG Reference to a national code

Ref country code: NL

Ref legal event code: MP

Effective date: 20230510

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20230510

Ref country code: NO

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20230810

Ref country code: NL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20230510

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: RS

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20230510

Ref country code: LV

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20230510

Ref country code: LT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20230510

Ref country code: IS

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20230910

Ref country code: HR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20230510

Ref country code: GR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20230811

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20230510

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SM

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20230510

Ref country code: SK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20230510

Ref country code: RO

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20230510

Ref country code: EE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20230510

Ref country code: DK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20230510

Ref country code: CZ

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20230510

REG Reference to a national code

Ref country code: DE

Ref legal event code: R097

Ref document number: 602018049628

Country of ref document: DE

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed

Effective date: 20240213

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SI

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20230510

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SI

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20230510

Ref country code: IT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20230510

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: MC

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20230510

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: MC

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20230510

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

REG Reference to a national code

Ref country code: AT

Ref legal event code: UEP

Ref document number: 1566781

Country of ref document: AT

Kind code of ref document: T

Effective date: 20230510

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LU

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20240131

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20240131

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LU

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20240131

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20240131

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: BE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20240131

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: CH

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20240131

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20240131

Ref country code: CH

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20240131

Ref country code: BE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20240131

REG Reference to a national code

Ref country code: BE

Ref legal event code: MM

Effective date: 20240131

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: BG

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20230510

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: BG

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20230510

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20240131

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20240131

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20250121

Year of fee payment: 8

Ref country code: PT

Payment date: 20250108

Year of fee payment: 8

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FI

Payment date: 20250121

Year of fee payment: 8

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: ES

Payment date: 20250203

Year of fee payment: 8

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: AT

Payment date: 20250121

Year of fee payment: 8

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20250117

Year of fee payment: 8

Ref country code: PL

Payment date: 20250107

Year of fee payment: 8

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: CY

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT; INVALID AB INITIO

Effective date: 20180131

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: HU

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT; INVALID AB INITIO

Effective date: 20180131

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: TR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20230510