WO2023249527A1 - Procédé et système de blanchiment de pâte à partir d'un matériau textile recyclé - Google Patents
Procédé et système de blanchiment de pâte à partir d'un matériau textile recyclé Download PDFInfo
- Publication number
- WO2023249527A1 WO2023249527A1 PCT/SE2023/050395 SE2023050395W WO2023249527A1 WO 2023249527 A1 WO2023249527 A1 WO 2023249527A1 SE 2023050395 W SE2023050395 W SE 2023050395W WO 2023249527 A1 WO2023249527 A1 WO 2023249527A1
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- WO
- WIPO (PCT)
- Prior art keywords
- bleaching
- pulp
- stage
- ozone
- arrangement
- Prior art date
Links
- 238000004061 bleaching Methods 0.000 title claims abstract description 263
- 238000000034 method Methods 0.000 title claims abstract description 50
- 239000000463 material Substances 0.000 title claims abstract description 30
- 239000004753 textile Substances 0.000 title claims abstract description 24
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 claims abstract description 98
- OSVXSBDYLRYLIG-UHFFFAOYSA-N dioxidochlorine(.) Chemical compound O=Cl=O OSVXSBDYLRYLIG-UHFFFAOYSA-N 0.000 claims abstract description 60
- 238000005406 washing Methods 0.000 claims abstract description 36
- 239000004155 Chlorine dioxide Substances 0.000 claims abstract description 30
- 235000019398 chlorine dioxide Nutrition 0.000 claims abstract description 30
- 229920002678 cellulose Polymers 0.000 claims abstract description 26
- 239000001913 cellulose Substances 0.000 claims abstract description 26
- 239000000654 additive Substances 0.000 claims description 24
- 238000004537 pulping Methods 0.000 claims description 11
- 239000002253 acid Substances 0.000 claims description 9
- 239000002738 chelating agent Substances 0.000 claims description 7
- 239000002516 radical scavenger Substances 0.000 claims description 7
- 239000007844 bleaching agent Substances 0.000 claims description 5
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims description 4
- 239000000460 chlorine Substances 0.000 claims description 4
- 229910052801 chlorine Inorganic materials 0.000 claims description 4
- 238000004519 manufacturing process Methods 0.000 claims description 2
- 230000001419 dependent effect Effects 0.000 claims 1
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 9
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 8
- 230000014759 maintenance of location Effects 0.000 description 8
- KCXVZYZYPLLWCC-UHFFFAOYSA-N EDTA Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O KCXVZYZYPLLWCC-UHFFFAOYSA-N 0.000 description 7
- 239000007789 gas Substances 0.000 description 7
- 238000009897 hydrogen peroxide bleaching Methods 0.000 description 7
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 6
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical compound [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 description 6
- QPCDCPDFJACHGM-UHFFFAOYSA-N N,N-bis{2-[bis(carboxymethyl)amino]ethyl}glycine Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(=O)O)CCN(CC(O)=O)CC(O)=O QPCDCPDFJACHGM-UHFFFAOYSA-N 0.000 description 6
- 238000007865 diluting Methods 0.000 description 6
- 238000010790 dilution Methods 0.000 description 6
- 239000012895 dilution Substances 0.000 description 6
- 230000000694 effects Effects 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 230000000996 additive effect Effects 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 229910052943 magnesium sulfate Inorganic materials 0.000 description 3
- 235000019341 magnesium sulphate Nutrition 0.000 description 3
- 229910021645 metal ion Inorganic materials 0.000 description 3
- 235000006408 oxalic acid Nutrition 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 230000008719 thickening Effects 0.000 description 3
- 238000011144 upstream manufacturing Methods 0.000 description 3
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 239000001110 calcium chloride Substances 0.000 description 2
- 229910001628 calcium chloride Inorganic materials 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 2
- 238000006731 degradation reaction Methods 0.000 description 2
- 239000000975 dye Substances 0.000 description 2
- 238000000605 extraction Methods 0.000 description 2
- 229960003330 pentetic acid Drugs 0.000 description 2
- 238000004064 recycling Methods 0.000 description 2
- 239000001117 sulphuric acid Substances 0.000 description 2
- 235000011149 sulphuric acid Nutrition 0.000 description 2
- 239000002023 wood Substances 0.000 description 2
- 229920003043 Cellulose fiber Polymers 0.000 description 1
- 229920000297 Rayon Polymers 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 239000008139 complexing agent Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 229920005610 lignin Polymers 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 230000002000 scavenging effect Effects 0.000 description 1
- 238000010517 secondary reaction Methods 0.000 description 1
- 230000008961 swelling Effects 0.000 description 1
- 230000002195 synergetic effect Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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
- 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
- D21C9/10—Bleaching ; Apparatus therefor
- D21C9/147—Bleaching ; Apparatus therefor with oxygen or its allotropic modifications
- D21C9/153—Bleaching ; Apparatus therefor with oxygen or its allotropic modifications with ozone
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08B—POLYSACCHARIDES; DERIVATIVES THEREOF
- C08B16/00—Regeneration of cellulose
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08H—DERIVATIVES OF NATURAL MACROMOLECULAR COMPOUNDS
- C08H8/00—Macromolecular compounds derived from lignocellulosic 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
- D21C5/00—Other processes for obtaining cellulose, e.g. cooking cotton linters ; Processes characterised by the choice of cellulose-containing starting 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
- D21C9/10—Bleaching ; Apparatus therefor
- D21C9/1057—Multistage, with compounds cited in more than one sub-group D21C9/10, D21C9/12, D21C9/16
-
- 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
- D21C9/10—Bleaching ; Apparatus therefor
- D21C9/12—Bleaching ; Apparatus therefor with halogens or halogen-containing compounds
- D21C9/123—Bleaching ; Apparatus therefor with halogens or halogen-containing compounds with Cl2O
-
- 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
- D21C9/10—Bleaching ; Apparatus therefor
- D21C9/12—Bleaching ; Apparatus therefor with halogens or halogen-containing compounds
- D21C9/14—Bleaching ; Apparatus therefor with halogens or halogen-containing compounds with ClO2 or chlorites
- D21C9/144—Bleaching ; Apparatus therefor with halogens or halogen-containing compounds with ClO2 or chlorites with ClO2/Cl2 and other bleaching agents in a multistage process
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H11/00—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only
- D21H11/12—Pulp from non-woody plants or crops, e.g. cotton, flax, straw, bagasse
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H11/00—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only
- D21H11/14—Secondary fibres
Definitions
- the invention relates to a method for bleaching pulp formed from recycled textile material comprising cellulose, which method comprises ozone bleaching.
- the invention also relates to a corresponding system.
- Renewcell has developed a process for recycling cellulose from textile material comprising cellulose, see for instance WO2018/073177A1. Recycled cellulose can be used for different purposes, for example for producing viscose.
- the need for de-colorization/bleaching of the recycled textile material is identified, and it is suggested to use a combination of oxygen and ozone bleaching.
- Ozone bleaching of cellulose pulp from wood material is well known in the art, where ozone reacts with and de-composes lignin originating from the wood material.
- the purpose of the ozone bleaching is somewhat different - mainly to bleach or decompose color pigments contained in the pulp, which pulp mainly consists of cellulose and liquid (water).
- pulp mainly consists of cellulose and liquid (water).
- ozone it has however proven challenging to achieve sufficient brightness of the resulting pulp.
- the oxidative properties of ozone will also attack the cellulose fibers and may reduce the viscosity of the resulting pulp to an unsatisfactorily low level.
- SE 544236C2 proposes ozone bleaching of pulp formed from recycled textile material by means of adding ozone at a significantly higher charges (at least 12 kg/odt) than what is normally used.
- An object of the invention is to provide a method and a system for bleaching pulp formed from recycled textile material with further improved performance in terms of brightness and/or ozone consumption and/or viscosity.
- a method for bleaching pulp formed from recycled textile material comprising cellulose.
- the method comprises subjecting the pulp to a first bleaching stage to obtain bleached pulp, washing the bleached pulp from the first bleaching stage to obtain washed and bleached pulp, and subjecting the washed and bleached pulp from the washing to a second bleaching stage, wherein said second bleaching stage comprises ozone bleaching.
- the first bleaching stage may comprise chlorine dioxide bleaching and/or ozone bleaching.
- the first bleaching stage may comprise hydrogen peroxide bleaching and/or oxygen bleaching.
- the method comprises two bleaching stages with an intermediate washing stage, wherein at least the second bleaching stage comprises ozone bleaching.
- the method is a method for bleaching pulp (previously) formed from recycled textile material comprising cellulose i.e. the forming of the pulp (the pulping stage) is not necessarily part of the method according to the first aspect of the invention.
- the method comprises providing pulp formed from recycled textile material comprising cellulose, which pulp is subjected to two bleaching stages with an intermediate washing stage.
- the second bleaching stage is described as comprising ozone bleaching, it may comprise additional steps, as will be explained in the embodiments below. It is furthermore understood that the method may comprise further stages prior or after the first bleaching stage and/or prior or after the second bleaching stage.
- the pulp may be provided to the first bleaching stage at high consistency (HC), for example at a consistency (by weight) of at least 30%, preferably within a range from 35-42%.
- the pulp may be provided to the first bleaching stage at medium consistency (MC), for example at a consistency (by weight) of 8-16%, preferably 10-12%.
- the pulp may be provided to the second bleaching stage also at high consistency (HC), for example at a consistency (by weight) of at least 30%, preferably within a range from 35-42%.
- Such high consistency to the second bleaching stage may be achieved by providing pulp at high consistency to the first bleaching stage followed by the washing stage and an optional dewatering stage before the second bleaching stage.
- the pulp may be provided to the second bleaching stage at medium consistency (MC), for example at a consistency (by weight) of 8-16%, preferably 10-12%.
- medium consistency to the second bleaching stage may be achieved by providing pulp at high consistency to the first bleaching stage followed by the washing and an optional diluting stage (or pretreating stage which comprises dilution) before the second bleaching stage.
- the pulp may be provided to the first bleaching stage at medium consistency (MC), for example at a consistency (by weight) of 8- 16%, preferably 10-12%.
- the pulp may be provided to the second bleaching stage also at medium consistency (MC), for example at a consistency (by weight) of 8-16%, preferably 10-12%.
- the pulp may be provided to the second bleaching stage at high consistency (HC), for example at a consistency (by weight) of at least 30%, preferably within a range from 35-42%.
- high consistency to the second bleaching stage may be achieved by providing pulp at medium consistency to the first bleaching stage followed by the washing and a dewatering stage before the second bleaching stage.
- Ozone may be added as a gas mixture, for example with 8-14 % ozone by weight in an ozoneair mixture.
- the ozone bleaching of a HC pulp may be performed for a duration of 10 seconds - 5 minutes, such as 30-60 seconds, for example at a temperature of 40-70°C.
- the invention is based on the insight that by providing an intermediate washing stage between the two washing stages, dissolved material resulting from the first bleaching stage will be removed which otherwise will consume ozone in the second bleaching stage without being useful for brightness increase of the pulp. In other words, a larger portion of the ozone charge provided to the second bleaching stage contributes to bleaching of the pulp. Thus, for a given desired brightness of the pulp, ozone consumption may be reduced compared with using an ozone bleaching stage without a preceding washing stage.
- the total ozone charge (of the second bleaching stage, and of the optional ozone bleaching of the first bleaching stage) may be less than 12 kg/odt, preferably less than 10 kg/odt, or less than 8 kg/odt.
- the total ozone charge of the first and second bleaching stages is less than 12 kg/odt, preferably less than 10 kg/odt, or less than 8 kg/odt.
- the first and/or second bleaching stage comprises ozone bleaching followed by chlorine dioxide bleaching.
- the first and/or second bleaching stage may be a ZD-stage.
- the chlorine dioxide bleaching may follow directly after the ozone bleaching, i.e. without intermediate washing, and may thus be referred to as a (ZD) stage.
- ZD ZD stage.
- This may be advantageous since a combination of chlorine dioxide and ozone results in a synergistic effect regarding brightness level. Therefore, an addition of chlorine dioxide directly after the ozone stage without intermediate washing will reinforce the bleaching effect.
- advantageous effects in terms of viscosity control may be achieved since ozone impacts viscosity while chlorine dioxide does not.
- the chlorine dioxide charge may, if only one of the first and second bleaching stages comprises chlorine dioxide bleaching, correspond to 30 kg active chlorine /odt or less. If both the first and the second bleaching stages comprise chlorine dioxide bleaching, the total chlorine dioxide charge may correspond to 40 kg active chlorine /odt or less.
- the first and/or second bleaching stages comprises ozone bleaching followed by hydrogen peroxide bleaching.
- the first and/or second bleaching stage may be a ZP-stage.
- the hydrogen peroxide bleaching may follow directly after the ozone bleaching, i.e. without intermediate washing, and may thus be referred to as a (ZP) stage.
- Hydrogen peroxide is a secondary reactions product in ozone bleaching, therefore an addition of hydrogen peroxide directly after the ozone stage without intermediate washing will reinforce the ozone bleaching stage.
- the total hydrogen peroxide charge of the first and/or second bleaching stages may be less than 40 kg hydrogen peroxide /odt.
- first bleaching stage is a (ZD)-stage and the second bleaching stage is a (ZP)- stage.
- the ozone bleaching in the first bleaching stage has a shorter retention time than the ozone bleaching in the second bleaching stage.
- the retention times it is understood that the consistency of the pulp fed to the (ozone bleaching of the) first and second bleaching stages must be substantially the same, i.e.
- the pulp is at high consistency (HC), for example at a consistency (by weight) of at least 30%, preferably within a range from 35-42% at both the first and second bleaching stages, or the pulp is at medium consistency (MC), for example at a consistency (by weight) of 8-16%, preferably 10-12% at both the first and second bleaching stages.
- HC high consistency
- MC medium consistency
- fresh ozone gas is supplied to, and counter currently charged in, the ozone bleaching second bleaching stage (and/or in the ozone bleaching of the first bleaching stage, if existing). This may provide advantageous bleaching results, in particular when the pulp subjected to bleaching has a high consistency (typically 30% or more).
- Such counter currently charging is most advantageous when the pulp fed to the ozone bleaching of the first and/or second bleaching stage is at HC (as defined above).
- the method further comprises pretreating the pulp prior to the second bleaching stage (between the washing stage and the second bleaching stage) and/or, if the first bleaching stage comprises ozone bleaching, prior to the first bleaching stage, wherein said pretreating comprises adding at least one acid to reduce the pH of the pulp and/or adding one or more additives.
- the one or more additives may be added together with, or simultaneously with the at least one acid. Alternatively, the one or more additives may be added prior to, or after the at least one acid.
- the at least one acid may comprise sulphuric acid.
- the at least one acid may be added at a charge such that the pH is reduced to within a range from 2 to 3, preferably from 2 to 2.5 or from 2.5 to 3.
- the one or more additives may comprise one or more chelating agents and/or radical scavengers.
- the one or more additives may be chosen from a group comprising oxalic acid, acetic acid, ethylenediaminetetraacetic acid, EDTA, diethylenetriaminepentaacetic acid, DTPA, magnesium sulfate or calcium chloride.
- the additives may be added at charge of 1-20 kg/odt, or more specifically if the additive is EDTA or DTPA at charge of 1-2 kg/odt.
- the first bleaching stage does not comprise ozone bleaching.
- the first bleaching stage may solely comprise chlorine dioxide bleaching.
- the second bleaching stage (and/or the first bleaching stage if it comprises ozone bleaching) comprises adding one or more additives, the additives comprising at least one chelating agent and/or at least one radical scavenger.
- the second bleaching stage (and/or the first bleaching stage) may be referred to as a Zq-stage.
- the one or more additives may be added directly after the ozone bleaching in the second bleaching stage (and/or in the first bleaching stage), i.e. without any intermediate washing or other step (a (Zq)-stage).
- the second bleaching stage (and/or in the first bleaching stage) may comprise a dilution step (using a dilution screw for example) directly after the ozone bleaching step in which dilution liquid and the at least one chelating agent and/or at least one radical scavenger is added.
- the one or more additives may alternatively be added before the ozone bleaching of the second bleaching stage (and/or in the first bleaching stage).
- Chelating agents which may also be referred to as complexing agents, provide the effect that selectivity in the ozone bleaching step is improved by reducing the content of metal ions in the pulp, which metal ions catalyze the degradation of ozone to free radicals, which in turn cause cellulose degradation.
- the one or more additives may be chosen from a group comprising oxalic acid, acetic acid, ethylenediaminetetraacetic acid, EDTA, diethylenetriaminepentaacetic acid, DTPA, magnesium sulfate or calcium chloride.
- the additives may be added at charge of 1-20 kg/odt, or more specifically if the additive is EDTA or DTPA at charge of 1-2 kg/odt.
- the embodiments described above may be combined, such that for example the first bleaching stage is a (Zq)-stage while the second bleaching stage is a (ZD) or (ZP) stage.
- the second bleaching stage (and/or the first bleaching stage if it comprises ozone bleaching) comprises alkaline extraction after the ozone bleaching.
- the second bleaching stage (and/or the first bleaching stage) may be a Ze-stage.
- a method for producing bleached cellulose pulp from recycled textile material comprising cellulose.
- the method comprises pulping the recycled textile material to form cellulose pulp and bleaching the cellulose pulp using a method according to the first aspect of the invention or embodiments thereof.
- a system for bleaching pulp formed from recycled textile material comprising cellulose.
- the system comprises a first bleaching arrangement arranged to bleach the pulp, a washing arrangement connected to the first bleaching arrangement and arranged to wash bleached pulp received from the first bleaching arrangement and a second bleaching arrangement connected to the washing arrangement and arranged to bleach washed pulp received from the washing arrangement.
- the first bleaching arrangement comprises at least one of an ozone bleaching apparatus, a chlorine dioxide bleaching apparatus, a hydrogen peroxide bleaching apparatus and an oxygen bleaching apparatus.
- the second bleaching arrangement comprises an ozone bleaching apparatus. It is understood that the second bleaching arrangement is physically separate from the first bleaching arrangement, i.e. the ozone bleaching apparatus and optional additional apparatuses of the second bleaching arrangement is/are separate from the bleaching apparatus(es) and optional additional apparatuses of the first bleaching arrangement.
- the system comprises a pulping arrangement arranged to receive the recycled textile material to produce pulp therefrom, wherein the first bleaching arrangement is arranged to receive pulp from the pulping arrangement.
- a pulping arrangement arranged to receive the recycled textile material to produce pulp therefrom, wherein the first bleaching arrangement is arranged to receive pulp from the pulping arrangement.
- Such an embodiment may be referred to as a system for producing bleached cellulose pulp from recycled textile material comprising cellulose.
- the first bleaching arrangement comprises an ozone bleaching apparatus and a chlorine dioxide bleaching apparatus arranged to receive bleached pulp directly from the ozone bleaching apparatus in the sense that there are no intermediate stages such as diluting or washing.
- the second bleaching arrangement further comprises a chlorine dioxide bleaching apparatus, wherein the chlorine dioxide bleaching apparatus is arranged to receive bleached pulp directly from the ozone bleaching apparatus in the sense that there are no intermediate stages such as diluting or washing.
- the system further comprises at least one pretreating arrangement arranged upstream of the first bleaching arrangement and/or upstream of the second bleaching arrangement (between the washing arrangement and the second bleaching arrangement), the pretreating arrangement being configured to add at least one acid to reduce the pH of the pulp and/or one or more additives, said one or more additives comprising at least one chelating agent and/or at least one radical scavenger.
- the ozone bleaching apparatus of the second bleaching arrangement (and/or of the first bleaching arrangement if it comprises an ozone bleaching apparatus) comprises means for supplying fresh ozone gas and counter currently charging the ozone gas in said ozone bleaching apparatus.
- the first and/or second bleaching arrangement comprises means for adding one or more additives.
- the additives may comprise at least one chelating agent and/or at least one radical scavenger.
- the means for adding may be arranged downstream of the ozone bleaching apparatus, if present.
- the means for adding may comprise a dilution screw directly after the ozone bleaching step in which dilution liquid and the one or more additives are added.
- the means for adding may be arranged upstream of the ozone bleaching apparatus.
- the first and/or second bleaching arrangements comprises an alkaline extraction apparatus downstream of the ozone bleaching apparatus.
- the first and/or second bleaching arrangements comprises a hydrogen peroxide bleaching apparatus.
- the hydrogen peroxide bleaching apparatus may be arranged downstream of the respective ozone bleaching apparatus (if present).
- the hydrogen peroxide bleaching apparatus may be arranged directly after the ozone bleaching apparatus in the sense that there are no intermediate stages such as diluting or washing.
- fig. 1 schematically illustrates embodiments of the methods according to the first and second aspects of the invention
- fig. 2 schematically illustrates other embodiments of the methods according to the first and second aspects of the invention.
- Fig. 1-2 also illustrate embodiments of the system according to the third aspect of the invention.
- Fig. 1 schematically illustrates an embodiment of the method according to the second aspect of the invention.
- the method comprises pulping 1 the recycled textile material to form cellulose pulp, for instance by swelling the material under reducing conditions as described in WO2018/073177A1.
- the pulping 1 may comprise washing the formed pulp.
- the pulp is pretreated 2 by adding sulphuric acid to reduce the pH of the pulp to within a range from 2 to 3.
- the pretreating also comprises adding one or more additives, the additives comprising at least one of oxalic acid, EDTA and magnesium sulfate.
- the pretreating stage may be referred to as an aq-stage.
- the additive(s) are added together with, or simultaneously with the at least one acid.
- the pretreatment may comprise diluting the pulp to low consistency prior to adding acid.
- the acidified pulp is subjected to an optional dewatering/thickening stage 3 such that the pulp is provided to the first bleaching stage 4 at high consistency (at least 30%, preferably within a range from 35- 42%).
- the first bleaching stage 4 comprises ozone bleaching, i.e. bleaching by means of adding ozone to the pulp followed directly by chlorine dioxide bleaching.
- the first bleaching stage is a (ZD)-stage. After the first bleaching stage 4, the pulp is washed 5 to remove dissolved material from the first bleaching stage, whereafter it is pretreated 6 once again in a corresponding manner as described above with reference to stage 2.
- the pretreated pulp is subjected to an optional dewatering/thickening stage 7 such that the pulp is provided to the second bleaching stage 8 at a HC consistency of at least 30%, preferably within a range from 35-42%.
- the second bleaching stage 8 comprises ozone bleaching followed directly by chlorine dioxide bleaching.
- the second bleaching stage is also a (ZD)-stage.
- the retention time of the ozone bleaching in the first bleaching stage is shorter than in the ozone bleaching of the second bleaching stage, however.
- fresh ozone gas is supplied to, and counter currently charged.
- Yet other embodiments correspond to the embodiment in fig. 1 except in that one or more of the dewatering stages 3, 7 is/are omitted or replaced with diluting stages such that the pulp is supplied to the bleaching stages 4, 8 at medium consistency (MC).
- the ozone gas is not counter currently charged.
- Steps 2-8 of fig. 1 also illustrate an embodiment of the method according to the first aspect of the invention.
- Fig. 2 schematically illustrates another embodiment of the method according to the second aspect of the invention.
- the method comprises a pulping/washing stage 11 , optional dewatering stages 13/17, washing stage 15 and a pretreating stage 16 corresponding to stages 1 , 3/7, 5 and 6, respectively in fig. 1.
- the embodiment in fig. 2 differs in that the first bleaching stage 14 solely comprises chlorine dioxide bleaching, and in that the second bleaching stage 18 solely comprises ozone bleaching.
- the first bleaching stage is a D- stage and the second bleaching stage is a Z-stage.
- the embodiment in fig. 2 further differs from fig. 1 in that the no pretreating stage before the first bleaching stage is present.
- Steps 13-18 of fig. 2 also illustrate an embodiment of the method according to the first aspect of the invention.
- ozone is added as a gas mixture, for example with 8- 16% ozone by weight in an ozone-air mixture, preferably 10-12% ozone by weight.
- the ozone bleaching of each of the first and second bleaching stages may be performed for a duration of 10-60 seconds at a temperature of 40-70°C.
- the overall ozone charge of the first and second bleaching stages combined amounts to less than 8g/odt, typically 5-6 kg/odt.
- Fig. 1-2 could also be said to illustrate embodiments of the system according to the third aspect of the invention, which embodiments comprises a pulping/washing arrangement 1/11 , pretreating arrangements 2, 6/16, dewatering/thickening arrangements 3/13, 6/16, ozone bleaching apparatuses 4, 8/18, chlorine dioxide bleaching apparatus 14, and washing apparatuses 5/15.
- Such arrangements and apparatuses are all well-known in the art and will not be described in further detail here.
- one or more of the bleaching stage(s) prior to or after the first and second bleaching step(s) may be added, or part(s) of the first and second bleaching stages (for example the chlorine dioxide bleaching in stages 4 and/or 8) may be omitted.
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- Chemical & Material Sciences (AREA)
- Biochemistry (AREA)
- Materials Engineering (AREA)
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Abstract
L'invention concerne un procédé de blanchiment de pâte formée à partir d'un matériau textile recyclé comprenant de la cellulose. Le procédé consiste à soumettre la pâte à une première étape de blanchiment (4 ; 14), à laver (5 ; 15) la pâte blanchie à partir de la première étape de blanchiment, et à soumettre la pâte lavée du lavage à une deuxième étape de blanchiment (8 ; 18), la première étape de blanchiment comprenant un blanchiment au dioxyde de chlore, et ladite deuxième étape de blanchiment comprenant un blanchiment à l'ozone. L'invention concerne également un système correspondant.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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SE2250746A SE545758C2 (en) | 2022-06-20 | 2022-06-20 | Method for bleaching pulp from recycled textile material |
SE2250746-1 | 2022-06-20 |
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WO2023249527A1 true WO2023249527A1 (fr) | 2023-12-28 |
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PCT/SE2023/050395 WO2023249527A1 (fr) | 2022-06-20 | 2023-04-27 | Procédé et système de blanchiment de pâte à partir d'un matériau textile recyclé |
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SE (1) | SE545758C2 (fr) |
WO (1) | WO2023249527A1 (fr) |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1995027100A1 (fr) * | 1994-04-05 | 1995-10-12 | Mo Och Domsjö Aktiebolag | Procede de traitement complexe de pate a papier combine a une etape de dioxyde de chlore |
EP0902120A1 (fr) * | 1997-09-15 | 1999-03-17 | L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude | Procédé de blanchissement d'une pâte à papier avec de l'ozone et du dioxyde de chlore |
US6153051A (en) * | 1989-05-05 | 2000-11-28 | International Paper Company | Method of bleaching kraft pulp employing chlorine dioxide/chlorine-ozone bleach sequence |
WO2018073177A1 (fr) | 2016-10-19 | 2018-04-26 | Re:Newcell Ab | Recyclage de textiles cellulosiques |
WO2018104330A1 (fr) * | 2016-12-06 | 2018-06-14 | Re:Newcell Ab | Fibres de cellulose |
SE2051513A1 (en) * | 2020-12-21 | 2022-03-08 | Valmet Oy | Method for bleaching pulp from recycled textile material |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2002069879A (ja) * | 2000-09-04 | 2002-03-08 | Nippon Paper Industries Co Ltd | セルロース質繊維材料のパルプの漂白方法 |
US20210054567A1 (en) * | 2013-04-17 | 2021-02-25 | Evrnu, Spc | Methods and systems for forming composite fibers |
WO2021006798A1 (fr) * | 2019-07-05 | 2021-01-14 | Kiram Ab | Procédé pour pâte à dissoudre à partir d'un matériau textile recyclé |
-
2022
- 2022-06-20 SE SE2250746A patent/SE545758C2/en unknown
-
2023
- 2023-04-27 WO PCT/SE2023/050395 patent/WO2023249527A1/fr unknown
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6153051A (en) * | 1989-05-05 | 2000-11-28 | International Paper Company | Method of bleaching kraft pulp employing chlorine dioxide/chlorine-ozone bleach sequence |
WO1995027100A1 (fr) * | 1994-04-05 | 1995-10-12 | Mo Och Domsjö Aktiebolag | Procede de traitement complexe de pate a papier combine a une etape de dioxyde de chlore |
EP0902120A1 (fr) * | 1997-09-15 | 1999-03-17 | L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude | Procédé de blanchissement d'une pâte à papier avec de l'ozone et du dioxyde de chlore |
WO2018073177A1 (fr) | 2016-10-19 | 2018-04-26 | Re:Newcell Ab | Recyclage de textiles cellulosiques |
WO2018104330A1 (fr) * | 2016-12-06 | 2018-06-14 | Re:Newcell Ab | Fibres de cellulose |
SE2051513A1 (en) * | 2020-12-21 | 2022-03-08 | Valmet Oy | Method for bleaching pulp from recycled textile material |
SE544236C2 (en) | 2020-12-21 | 2022-03-08 | Valmet Oy | Method for bleaching pulp from recycled textile material |
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SE2250746A1 (en) | 2023-12-21 |
SE545758C2 (en) | 2024-01-02 |
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