Method and system for recovering at least portion of textile material comprising polyester fibers

Abstract

The invention describes a process for recovering at least a portion of a textile material comprising polyester fibers, said process comprising:-a mixing step comprising contacting a textile material comprising polyester fibers and at least one other type of fiber with a suspension comprising a catalyst and methanol in a rotatable drum of a reactor unit, the rotatable drum is arranged to be adapted to rotate about an axis, the axis having an angle of less than 45 DEG with respect to the horizontal plane, preferably the rotatable drum is porous; -a depolymerization step comprising setting a temperature of at least 80 DEG C in the reactor unit and rotating the drum so as to roll the textile material inside it into contact with the catalyst and methanol to carry out a methanol decomposition depolymerization reaction of the polyester fraction of the textile material while maintaining the other types of fibers in the fibrous state; and-discharging a liquid solution comprising the depolymerized polyester from the reactor unit and discharging fibrous material comprising said other types of fibers from the rotatable drum.

Description

Technical Field

[0001] The present invention relates to a method and a system for recycling at least a portion of a textile material comprising polyester fibers. Background Art

[0002] There are known methods for recovering polyester from polyester textiles. One such is disclosed in WO 2018 / 150028. WO 2018 / 150028 describes a polyester textile waste recovery method. In the method, a polyester textile is soaked in a mixture comprising a solvent and a catalyst containing calcium oxide, and the mixture is heated to a temperature in the range of 80°C to 240°C, and the temperature is maintained in this range during the depolymerization of the polyester in the polyester textile.

[0003] It is an object of the present invention to provide a method and a system for improving the depolymerization of polyester, especially in textile recycling systems. Summary of the invention

[0004] The present invention provides a novel method for recycling textile materials containing polyester fibers, which involves a novel reactor unit for depolymerization of polyester in the textile material. In addition, the present invention also provides a textile recycling system comprising such a reactor unit.

[0005] The above objects are achieved by a method for recycling at least a portion of a textile material comprising polyester fibers, the method comprising:

[0006] - a mixing step, the mixing step comprising contacting the textile material comprising polyester fibers and at least one other type of fibers with a suspension comprising a catalyst and methanol in a rotatable drum of a reactor unit, the rotatable drum being arranged to rotate around an axis, the angle of the axis with the horizontal plane being less than 45°;

[0007] - a depolymerization step, which comprises setting a temperature of at least 80° C. in a reactor unit, exposing the textile material to a catalyst and methanol to carry out a methanolysis depolymerization reaction of the polyester part of the textile material, while maintaining the other type of fibers in a fibrous state;

[0008] wherein the drum is rotated during at least one of the mixing step and the depolymerization step to cause the textile material to tumble inside the drum to contact the catalyst and the methanol;

[0009] as well as

[0010] - discharging the liquid solution comprising the depolymerized polyester from the reactor unit and discharging the fibrous material comprising said other type of fibers from the rotatable drum.

[0011] The method according to the invention involves a tumbling process, in which it is ensured that the textile material comprising polyester fibers and another fiber type is contacted with a suspension comprising a catalyst and methanol by rotating in a rotatable drum of a reactor unit. This rotation process is advantageous when mixing different components and is therefore adopted during the mixing step and / or the depolymerization step. This is also why the method involves the rotation of the drum during at least one of the mixing step and the depolymerization step, and preferably the reason for the rotation during at least a part of the two steps. The method provides an effective way to separate the polyester that is depolymerized under the action of the catalyst and methanol to form a solution of depolymerized polyester from other fibers, such as cellulose fibers such as cotton fibers, that are maintained in a fibrous state (i.e. in a solid state). In addition, during one or more subsequently suggested rinsing steps, the rotation of the drum is also preferred, which is discussed further below.

[0012] Furthermore, since the rotation should be performed for contacting the fibers with the suspension, a regular rotation about a substantially horizontal axis is preferred. Furthermore, according to the invention, rotations with slightly inclined planes and angles are possible. Thus, according to the invention, the rotatable drum is arranged to be suitable for rotating about an axis with an angle of less than 45° to the horizontal. However, it should be noted that according to the invention, an angle with the horizontal plane lower than 25°, for example lower than 10° or even close to 0° or 0° is preferred.

[0013] It should be noted that the rotatable drum inside the housing of the pressure vessel is preferably a porous drum. This is preferred because it simplifies the separation of the methanol-monomer solution from the textile remaining in the rotatable drum after reaction, discharge and centrifugal drying.

[0014] According to one embodiment of the invention, during at least a part of the depolymerization step, the temperature in the reactor unit may be set at a temperature of at least 100° C., preferably at least 110° C., more preferably at least 120° C., and most preferably at least 140° C. At such temperatures, the process becomes increasingly efficient.

[0015] According to one embodiment of the invention, during at least a portion of the depolymerization step, the temperature in the reactor unit may be set at a temperature of 200° C. or less, preferably 180° C. or less, and most preferably 170° C. or less. At such temperatures, undesired decomposition of the other types of fibers is reduced.

[0016] According to one embodiment of the present invention, during at least a portion of the depolymerization step, the temperature in the reactor unit may be set in the range of 100°C to 200°C, preferably in the range of 110°C to 180°C, more preferably in the range of 120°C to 170°C, most preferably in the range of 140°C to 170°C. In the presence of some fiber materials sensitive to high temperatures, such as cotton, a temperature below 200°C is preferred for depolymerization of the polyester. In addition, methanol performs best at temperatures below 200°C. In addition, at temperatures below 100°C, the yield of the depolymerized polyester is too low.

[0017] According to one embodiment of the invention, during at least a portion of the depolymerization step, the pressure in the reactor unit may be maintained at an absolute pressure of at least 5 bar, preferably at least 10 bar. The pressure depends on the temperature and the vapor pressure of the solvent at that particular temperature. Based on the solvent used and the temperature set, the pressure results from the pressure-temperature dependence of the solvent.

[0018] According to one embodiment of the present invention, the at least one other fiber type of the textile material may include cellulose-based fibers, preferably natural cellulose fibers such as cotton and linen and at least one of man-made cellulose fibers such as viscose, lyocell, rayon and modal, more preferably the at least one other fiber type includes at least cotton.

[0019] According to another embodiment of the present invention, the textile material may contain at least 20% by weight, or at least 30% by weight, preferably at least 40% by weight, more preferably at least 50% by weight of cellulose-based fibers, preferably the textile material contains at least 20% by weight, or at least 30% by weight, preferably at least 40% by weight, more preferably at least 50% by weight of cotton fibers, and more preferably the textile material contains at least 20% by weight, or at least 30% by weight, more preferably at least 40% by weight, and more preferably at least 60% by weight of polyester-cotton composite (polycotton) textile material.

[0020] According to one embodiment of the present invention, the catalyst may contain Ca, preferably the catalyst comprises at least one of CaO, CaO-MgO and Ca(OH)2. According to another embodiment of the present invention, the specific surface area of ​​the catalyst may be at least 5 m 2 / g, preferably at least 10m 2 / g, more preferably at least 15m 2 / g, most preferably at least 20m 2 According to another embodiment of the present invention, the catalyst is used at 0.05 m / g of textile. 2 Up to 0.5m 2 The concentration is preferably 0.08 m / g of textile.2 Up to 0.4m 2 concentration added.

[0021] According to one embodiment of the present invention, the methanolysis depolymerization reaction can be carried out in an inert atmosphere in the reactor unit, preferably in a N2 environment. The inert environment can prevent undesired reactions.

[0022] According to another embodiment of the present invention, the method may include at least one subsequent rinsing step for rinsing the fibrous material remaining after the depolymerization of the polyester. Preferably, the subsequent rinsing step is carried out in methanol charged to the reactor unit. Preferably, the rotatable drum is rotated during at least a portion of the rinsing step. According to another embodiment of the present invention, the method may include a plurality of rinsing steps. According to another embodiment of the present invention, the at least one rinsing step comprises a centrifugal dry spinning means for separating the methanol and the depolymerized polyester relative to the fibrous material. Further, the at least one and initial rinsing step and any additional further rinsing steps may include a discharge before methanol can be added to the reactor unit for the rinsing step, or the rinsing may be carried out after the discharge before methanol can be added to the reactor unit for the rinsing step. Preferably, the method may include a discharge and several rinsing steps in which methanol is added to the reactor unit. Even more preferably, the discharge may be carried out at a temperature range of 120°C to 160°C, and the rinsing may be carried out at a temperature range of 60°C to 200°C.

[0023] According to one embodiment of the present invention, the fibrous material remaining in the rotatable drum after depolymerization of the polyester can be dried by applying a vacuum to the reactor unit. Also during the drying process, it is preferred to keep the rotatable drum rotating. Furthermore, it is preferred to evaporate and remove the methanol before discharging any fibrous material from the drum.

[0024] According to one embodiment of the invention, after the depolymerization step, the discharge and / or the flushing step, the catalyst and methanol solution may be discharged through an outlet having a particle filter. This may be done to filter out catalyst particles. This may preferably be done for further use of the catalyst particles.

[0025] According to one embodiment of the present invention, the produced depolymerized polyester (dimethyl terephthalate, DMT) can be concentrated, cooled and crystallized after the rinsing step. This can achieve the separation of DMT and the recycling and reuse of methanol to the reactor unit. Preferably, DMT can be cooled and crystallized in a separate crystallization reactor unit.

[0026] According to one embodiment of the invention, the methanol may be recovered via at least one evaporation step or via distillation.

[0027] According to a second aspect of the present invention, the present invention is a textile recycling system for recycling at least a portion of a textile material containing polyester fibers, the system being arranged to be suitable for carrying out a methanolysis depolymerization reaction of the polyester fibers and maintaining another type of fiber contained in the textile material in a fibrous state, the recycling system comprising a depolymerization reactor unit, the depolymerization reactor unit comprising a rotatable drum, the rotatable drum being arranged to be suitable for rotating around an axis, the angle of the axis to the horizontal plane being less than 45°, and the depolymerization reactor unit being a pressure vessel suitable for withstanding a temperature of at least 80°C, preferably suitable for withstanding a pressure of at least 5 bar, more preferably at least 10 bar absolute pressure.

[0028] According to an embodiment of the invention, during rotation of the rotatable drum, the angle of the shaft to the horizontal plane may be less than 25°. Preferably, the angle to the horizontal plane may be in the range of 0° to 10°.

[0029] According to another embodiment of the invention, the rotatable drum may be perforated. Perforations are preferred to enable separation of the methanol-monomer solution from the remaining textile after the depolymerization reaction and / or any possible subsequent steps such as rinsing.

[0030] According to one embodiment of the present invention, the rotatable drum can be arranged inside the shell of the reactor unit. The shell can be arranged to maintain the desired pressure in the reactor unit and collect the solution discharged through the perforations of the porous rotatable drum. In a preferred embodiment, the rotatable drum can be provided with perforations in its mantle portion and / or in at least one of its gable portions. In addition, in a more preferred embodiment, the rotatable drum can be provided with perforations in its mantle portion and in at least one of its gable portions. In a further preferred embodiment, the rotatable drum can include perforations in its mantle portion and in its two gable portions.

[0031] According to one embodiment of the present invention, the textile recycling system further comprises a separate charging device. The separate charging device can be used to charge the reactor unit.

[0032] According to one embodiment of the invention, the depolymerization reactor unit may comprise a heating device. According to a preferred embodiment, such a heating device may be arranged inside the housing of the reactor unit. In a still more preferred embodiment, the heating device may be arranged at least partially in the space between the housing of the reactor unit and the drum of the rotatable drum. Furthermore, the heating of the reactor may be performed by using different types of fluids in the drum, such as oil.

[0033] According to another embodiment of the invention, the depolymerization reactor unit may be connected to an outlet with a particle filter.

[0034] According to one embodiment of the present invention, the textile recycling system may further include a crystallization reactor unit. The crystallization unit may be connected to the depolymerization reactor unit. In a preferred embodiment, the crystallization unit may further include a recirculation loop. The recirculation loop may be used to recirculate the solvent from the crystallization reactor unit to the depolymerization reactor unit. In a preferred embodiment, the recirculation loop may be carried out via at least an evaporator unit or via a distillation unit or a combination thereof.

[0035] According to one embodiment of the invention, the system may be arranged to rotate the rotatable drum in a centrifugal drying mode. This may be done for separating the solution comprising methanol and depolymerized polyester from the fibrous material after the depolymerization step and / or for separating methanol from the fibrous material in the rinsing step. According to another embodiment of the invention, the rotatable drum may be arranged to be suitable for keeping the fibrous material inside the rotatable drum during such centrifugal drying, and for releasing the solution from the drum via the perforations and being collected in the housing of the reactor unit and subsequently discharged via the discharge outlet.

[0036] According to one embodiment of the present invention, the system may include a vacuum device. The vacuum device may be used to apply a vacuum to the reactor unit for drying the fiber material retained in the rotatable drum by evaporation of methanol. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] exist Figure 1 In the figure, a schematic diagram of the steps involved in at least one embodiment of the method according to the present invention is shown.

[0038] exist Figure 2 In the figure, a schematic diagram of the steps involved in at least one embodiment of the method according to the present invention is shown.

[0039] exist Figure 3 , a schematic diagram of an embodiment of a textile recycling system according to the present invention is shown.

[0040] exist Figure 4 , a schematic diagram of another embodiment of a textile recycling system according to the present invention is shown.

[0041] exist Figure 5 , a schematic cross-sectional view of an embodiment of a recovery system according to the present invention is shown.

[0042] exist Figure 6 , a schematic diagram of an embodiment of a recovery system according to the present invention is shown.

[0043] exist Figure 7, a schematic side view of an embodiment of a recovery system according to the present invention is shown. DETAILED DESCRIPTION

[0044] Specific embodiments of the present invention are disclosed and further described below.

[0045] According to one embodiment, during at least a portion of the depolymerization step, the temperature in the reactor unit is set in the range of 100°C to 200°C, preferably in the range of 110°C to 180°C, more preferably in the range of 120°C to 170°C, most preferably in the range of 140°C to 170°C. Above 200°C, it is not preferred to carry out the depolymerization of some fiber materials such as cotton. In addition, methanol is also adversely affected at high temperatures. Moreover, at temperatures below 100°C, the yield of depolymerized polyester is too low. Considering these aspects, a temperature range of 140°C to 170°C is preferred.

[0046] Pressure is also a relevant feature. According to another embodiment, during at least a portion of the depolymerization step, the pressure in the reactor unit is maintained at an absolute pressure of at least 5 bar, preferably at least 10 bar. Pressures up to or above 20 bar are also entirely possible. Preferably, the pressure is less than 40 bar, such as less than 30 bar. Preferably, during at least a portion of the depolymerization reaction, the pressure in the reactor is maintained in the range of 10 to 25 bar absolute pressure.

[0047] Furthermore, according to a preferred embodiment, the rotatable drum is provided with perforations, preferably at least on the shell surface.

[0048] Furthermore, not only temperature and pressure, controlling the reactor environment may also be relevant. For example, setting a suitable gas environment in the reactor unit is also of interest. As an example, according to one embodiment of the present invention, the methanol decomposition depolymerization reaction is carried out in an inert atmosphere in the reactor unit, preferably in a N2 environment. This prevents undesirable reactions.

[0049] In addition to polyester fibers, different fiber types can also be used in the fiber blend according to the present invention. In line with this, according to one embodiment of the present invention, the at least one other fiber type of the textile material comprises cellulose-based fibers, preferably at least one of natural cellulose fibers such as cotton and linen and man-made cellulose fibers such as viscose, lyocell, rayon and modal, more preferably the at least one other fiber type comprises at least cotton.

[0050] In addition, according to another embodiment, the textile material comprises at least 30% by weight, preferably at least 40% by weight, more preferably at least 50% by weight of cellulose-based fibers, preferably the textile material comprises at least 30% by weight, preferably at least 40% by weight, more preferably at least 50% by weight of cotton fibers, and more preferably the textile material comprises at least 30% by weight, preferably at least 40% by weight, more preferably at least 60% by weight of polyester-cotton composite textile material. As will be understood from the above, according to the present invention, polyester-cotton composites are preferred fiber blends to be used.

[0051] According to the present invention, different catalysts can be used. According to another embodiment of the present invention, the catalyst comprises Ca, preferably the catalyst comprises at least one of CaO, CaO-MgO and Ca(OH)2.

[0052] Calcium channels are a key characteristic of the catalyst to be used according to the present invention. In addition, other parameters are also relevant. Among such parameters is the specific surface area. High specific surface area can be obtained by providing relatively small catalyst particles. As an example, grinding can be used to ensure the expected maximum size. The total catalyst surface area is usually measured by using the BET (Brunauer-Emmett-Teller) method. According to one embodiment of the present invention, the total surface area of ​​the catalyst is at least 5m 2 / g, preferably at least 10m 2 / g, more preferably at least 15m 2 / g, most preferably at least 20m 2 According to another embodiment of the present invention, the catalyst is 0.05 m / g of textile. 2 Up to 0.5m 2 The concentration is preferably 0.08 m 2 Up to 0.4m 2 An example is 0.05 m3 / g of textile. 2 Catalyst, or 0.15m per gram of textile 2 Catalyst, or 0.3m per gram of textile 2 catalyst.

[0053] In addition, according to one embodiment of the present invention, after the depolymerization step or the rinsing step, the catalyst and the methanol solution are fed through an outlet with a particle filter to filter out the catalyst particles, which are preferably used for further use. The catalyst used can be filtered out, and then the waste stream is followed, and recycling is another possibility. According to this embodiment, the residue and the catalyst used or the unused catalyst particles are filtered out. However, DMT (depolymerized polyester) is passed through the filter for the next step in the method. In addition, in this method, the residue of the catalyst is subsequently washed out from the treated textile material.

[0054] In line with the above, according to another embodiment of the present invention, the method comprises at least one subsequent flushing step, preferably carried out in methanol charged to the reactor unit, preferably the rotatable drum is rotated during at least a part of the flushing step, more preferably the method comprises a plurality of flushing steps.

[0055] Furthermore, the at least one washing step preferably comprises centrifugal drying spinning means for separating methanol and depolymerized polyester from the fiber material. Here, too, spinning is involved in the method according to the invention.

[0056] According to another embodiment of the present invention, the at least one flushing step and any additional flushing step comprises a discharge before adding methanol to the reactor unit, or the flushing is performed after a discharge before adding methanol to the reactor unit, preferably the method comprises a discharge and several flushing steps wherein methanol is added to the reactor unit, more preferably wherein the discharge is performed at a temperature in the range of 120°C to 160°C and the flushing is performed at a temperature in the range of 60°C to 200°C.

[0057] According to another embodiment of the present invention, the produced depolymerized polyester (dimethyl terephthalate, DMT) is concentrated, cooled and crystallized after the washing step to achieve separation of DMT and recycling and reuse of methanol to the reactor unit, preferably DMT is cooled and crystallized in a separate crystallization reactor unit.

[0058] Furthermore, according to one embodiment of the invention, the methanol is recovered via at least one distillation or evaporation step. After the final centrifugal drying, the reactor is connected to a vacuum to evaporate any residual methanol from the remaining textile while spinning the textile. Since the reactor is still hot, this means that the textile in the reactor is drum-dried.

[0059] The present invention also relates to a textile recycling system comprising a methanolysis depolymerization reactor unit. According to the present invention, there is provided a textile recycling system for recycling at least a portion of a textile material comprising polyester fibers, the system being arranged to be suitable for carrying out a methanolysis depolymerization reaction of the polyester fibers and maintaining another type of fiber contained in the textile material in a fibrous state, the recycling system comprising a depolymerization reactor unit, the depolymerization reactor unit comprising a rotatable drum, the rotatable drum being arranged to be suitable for rotating around an axis, the angle of the axis to the horizontal plane being less than 45°, and the depolymerization reactor unit being a pressure vessel suitable for withstanding a temperature of at least 80°C, preferably suitable for withstanding a pressure of at least 5 bar, more preferably at least 10 bar.

[0060] As mentioned above, the rotatable drum is preferably arranged to rotate about a substantially horizontal axis, but some variations are possible. In line with this, according to one embodiment, the angle with the horizontal plane is less than 25°, preferably in the range of 0° to 10°.

[0061] Preferably, the rotatable drum is porous to enable separation of the methanol-monomer solution from the remaining textile after the depolymerization reaction and possible subsequent steps. The rotatable drum is arranged inside the housing of the reactor unit. The housing is arranged to maintain the desired pressure in the reactor unit and to collect the solution discharged via the perforations of the porous rotatable drum. Preferably, the rotatable drum is provided with perforations in its body part and / or in at least one of its flat sides, more preferably, the rotatable drum is provided with perforations in its body part and in at least one of its flat sides, still more preferably, the rotatable drum comprises perforations in its body part and in both of its flat sides.

[0062] Preferably the depolymerization reactor unit comprises a heating device. This makes it easier to maintain the desired process temperature during the depolymerization reaction. Preferably, such a heating device is arranged inside the housing of the reactor unit. Still more preferably, the heating device is at least partially arranged in the space between the housing of the reactor unit and the drum of the rotatable drum. The heating device of the system according to the invention is suitable for heating to at least 80°C, preferably at least 100°C, more preferably at least 120°C, more preferably at least 140°C, most preferably at least 170°C, or even up to at least 200°C.

[0063] Furthermore, cooling means may also be relevant for incorporation. Such cooling means may be included in the mechanical lining of the reactor unit.

[0064] Furthermore, the textile recycling system according to the present invention is preferably based on the use of vacuum as a means for charging the reactor unit. The textile recycling system may also include a separate charging device for charging the reactor unit. The reactor unit acts as a pressure vessel to enable an efficient depolymerization reaction. This type of system is also simple in terms of applying an inert environment, which is a benefit as described above. The system according to the present invention may alternatively be based on the incorporation of a pump for charging, however, this has the disadvantage of ensuring ATEX classification for certain equipment, as methanol is considered a flammable solvent.

[0065] As described above, the rotation of the drum (preferably porous) of the reactor unit is an important aspect according to the present invention. First, during charging, rotation is meaningful because it increases the uniform distribution of the catalyst particles on the textile material. Secondly, during the rinsing step after the depolymerization reaction is carried out, rotation is important to separate the methanol in the solution and the depolymerized polyester relative to the fiber material inside the drum. Of course, rotation can also be performed during at least a portion of the depolymerization reaction. It should also be noted that during the process of this method, the direction of rotation can be one and the same, or can alternate at least once. The distribution of the catalyst throughout the textile material is important, and changing the direction of rotation can help reduce the risk of entanglement of the textile material to be treated. For this reason, the drum can be provided with internal paddles to improve the mixing of the textile with the catalyst and methanol.

[0066] Furthermore, according to another embodiment, the textile recycling system further comprises a separate charging device for charging the reactor unit. This may be useful to simplify charging by means of vacuum and to ensure an inert atmosphere in the reaction unit if required. A suitable charging device is a charging container.

[0067] Furthermore, according to one embodiment of the invention, the depolymerization reactor unit is connected to an outlet having a particle filter. Here, still present catalyst particles can be filtered out together with any solid textile fragments and other particles (eg particulate pigments).

[0068] According to another embodiment of the present invention, the textile recycling system further comprises a crystallization reactor unit, which is connected to the depolymerization reactor unit, preferably also comprising a recirculation loop for recycling the solvent from the crystallization reactor unit to the depolymerization reactor unit, preferably via at least a distillation unit or an evaporator unit or a combination thereof. As an example, a thin film evaporator may be included in the system according to the present invention. In the system according to the present invention, it is of course of interest to recover and recycle the methanol for its reuse.

[0069] Detailed description of the drawings

[0070] Attached below is a detailed description of the drawings.

[0071] Figure 1 A schematic diagram is shown of the steps involved in one embodiment of a method 100 according to the present invention. The method 100 comprises three steps, 110, 120, 130a and 130b.

[0072] A textile material comprising polyester fibers and at least one other type of fiber is loaded into a depolymerization reactor unit comprising a rotatable drum. The at least one other fiber type of the textile material may include cellulose-based fibers. It may preferably be at least one of natural cellulose fibers such as cotton and flax and man-made cellulose fibers such as viscose, lyocell, rayon and modal, more preferably the at least one other fiber type includes at least cotton. In addition, the textile material may contain at least 30% by weight, preferably at least 40% by weight of cellulose-based fibers. For example, at least 50% by weight of cellulose-based fibers. In addition, the textile material may contain at least 30% by weight, preferably at least 40% by weight of cotton fibers, for example at least 50% by weight of cotton fibers. Further, the textile material may contain at least 60% by weight of a polyester-cotton composite textile material.

[0073] After the textile material, a suspension comprising the catalyst and methanol is loaded into the reactor unit. Alternatively, but sometimes less preferably, the catalyst can be added in solid form, and methanol is thereafter added and mixed with the catalyst and the textile. The catalyst can comprise Ca, preferably the catalyst can comprise at least one of CaO, CaO-MgO and Ca(OH)2. In this regard, it should be noted that CaMg(CO3)2, for example present in the mineral dolomite, can act as a raw material, which is calcined (heat treated) during the preparation of the catalyst and becomes CaO-MgO, which oxide then acts as a catalyst.

[0074] The first step 110 of the method 100 is a mixing step 110. In the first step 110, a textile material comprising polyester fibers and at least one other type of fiber is contacted with a suspension comprising a catalyst and methanol in a rotatable drum of a reactor unit. The rotatable drum is arranged to be suitable for rotation around an axis, the angle of the axis to the horizontal plane being less than 45°. For example, the angle can be less than 25°, for example in the range of 0° to 10°. The angle of the rotatable drum to the horizontal plane ensures proper mixing of the textile material and the suspension during tumbling of the rotatable drum.

[0075] The second step 120 is a depolymerization step 120, which includes setting a temperature of at least 80°C in the reactor unit and rotating the drum to tumble the textile material inside it. During at least a portion of the depolymerization step, the temperature in the reactor unit may be in the range of 100°C to 200°C. Preferably, the temperature may be in the range of 110°C to 180°C, such as in the range of 120°C to 170°C, or in the range of 140°C to 170°C. In addition, during at least a portion of the depolymerization step, the pressure in the reactor unit may be maintained at at least 5 bars, such as at least 10 bars, such as up to or above 20 bars. The pressure will depend on the temperature. Tumbling during the depolymerization step 120 contacts the textile with the catalyst and methanol to perform a methanolysis depolymerization reaction of the polyester part of the textile material, while maintaining the other types of fibers in a fibrous state. The drum is rotated during at least one of the mixing step 110 and the depolymerization step 120.

[0076] The third step has two parallel sub-steps 130a and 130b. During the third steps 130a and 130b, the textile material is discharged in two parts. One part 130a discharges the depolymerized polyester from the reactor unit, and the second part 130b discharges the fiber material containing the other type of fiber from the reactor unit.

[0077] As in Figure 1 and Figure 2 As can be seen in both, the fiber material remaining in the rotatable drum 220 after depolymerization of the polyester may be dried by applying a vacuum 125 to the reactor unit 210 to evaporate the methanol.

[0078] During the process, the atmosphere is suitably inert. For example, the methanolysis depolymerization reaction can be carried out in an inert atmosphere in the reactor unit. To obtain an inert atmosphere, N2 can be introduced into the reactor unit during any step.

[0079] Figure 2 1 shows a schematic diagram of the steps involved in one embodiment of a method 100 according to the present invention. The first two steps 110 and 120 are related to Figure 1 Therefore, Figure 2 The focus of the relevant description will be on the additional third step 140 and fourth step 150 .

[0080] The third step 140 is a rinsing step. The rinsing step 140 may include a discharge step 140a. The discharge step 140a discharges methanol and depolymerized polyester from the drum. There may be multiple rinsing steps 140 performed one after another, for example up to three steps or more. At least one rinsing step 140 is preferably performed in methanol loaded into the reactor unit. Preferably, the rotatable drum is rotated during at least a portion of at least one rinsing step 140. The rinsing step 140 may include sub-steps 140a, 140b and 140c. At least one rinsing step 140 may include a discharge 140a, one or more rinsing steps 140b and a centrifugal drying 140c rotation means step. The centrifugal drying step 140c includes rotating the rotatable drum at such a rpm: a large amount of methanol and depolymerized polyester leave the remaining fiber material due to centrifugal action. Suitably, in order to more effectively remove the methanol-monomer solution from the textile, after the discharge 140a, a centrifugal drying step 140c is involved. In order to remove as much methanol as possible from the remaining textile, centrifugal drying 140c is appropriately repeated after each rinsing step 140b.

[0081] During the discharge 140a and the flush 140b, methanol may be added to the reactor unit. Preferably, the discharge 140a is performed at a temperature in the range of 120°C to 160°C, and the flush 140b is performed at a temperature in the range of 60°C to 200°C.

[0082] After the depolymerization step or one or more washing steps 140, the catalyst and methanol solution can be discharged through an outlet having a particle filter to filter out catalyst particles. Preferably, the catalyst and methanol can be reused in the process. The methanol can be recovered via at least one distillation or evaporation step.

[0083] The fourth step is cooling and crystallizing 150 the depolymerized polyester (dimethyl terephthalate, DMT) from step 130a. This allows the DMT to be separated and the methanol to be recycled and reused to the reactor unit. The DMT is preferably cooled and crystallized 150 in a separate crystallization reactor unit.

[0084] exist Figure 3 In the figure, a schematic diagram of an embodiment of a textile recycling system 200 according to the present invention is shown. The system 200 is arranged to be suitable for performing a methanolysis depolymerization reaction of polyester fibers while maintaining another type of fiber contained in the textile material in a fibrous state. The recycling system 200 includes a depolymerization reactor unit 210. The reactor unit 210 includes a rotatable drum 220. The rotatable drum 220 is arranged to be suitable for rotation around an axis. The angle of the axis A with the horizontal plane is less than 45°, for example less than 25° or preferably in the range of 0° to 10°. Figure 3Axis A in should be interpreted as entering the plane of the figure. In a preferred embodiment, the reactor unit 210 also includes a paddle 225. The paddle 225 can be used to improve the tumbling of the textile. Improved tumbling can provide better mixing of the textile with the suspension of catalyst and methanol. The reactor unit 210 can also include a heating device 230. The heating device 230 can be used to set the reactor unit 210 at a temperature of at least 80°C. For example, it is set to a temperature in the range of 100°C to 200°C, for example in the range of 110°C to 180°C, more preferably in the range of 120°C to 170°C, and most preferably in the range of 140°C to 170°C. In addition, a cooling device is also preferably provided to enable cooling of the reactor unit. Heating and cooling can be achieved via the jacket of the reactor unit 210.

[0085] In addition, as described, the reactor unit 210 is a pressure vessel. In a preferred embodiment, the reactor unit is adapted to withstand a pressure of at least 5 bar, even more preferably at least 10 bar. It should be noted that the method and system according to the present invention can be carried out at a pressure in the range of 15 bar to 20 bar and even higher.

[0086] exist Figure 4 , a schematic diagram of an embodiment of a textile recycling system 200 according to the present invention is shown. Figure 4 Existence and Figure 3 Therefore, Figure 4 The focus of the related description will be on other parts of the system 200.

[0087] The textile recycling system 200 may also include a charging device 240 for charging the reactor unit 210. The charging device 240 may be used to charge nitrogen, catalyst and methanol to the reactor unit 210 throughout the use of the system. The rotatable drum 220 may be provided with a cover (not shown) for charging the drum with textile material to be treated according to the method, and for discharging the remaining fiber material from the drum after depolymerization and any rinsing.

[0088] Furthermore, the depolymerization reactor unit 210 may also include an outlet 250 having a particle filter 260. The particle filter 260 may be used to separate and filter particles from the depolymerization reactor unit, such as spent catalyst and particles still in suspension.

[0089] The textile recycling system 200 may further include a crystallization reactor unit 270. The crystallization reactor unit 270 may be connected to the depolymerization reactor unit 210. Preferably, the textile recycling system further includes a recirculation loop 280. The recirculation loop 280 may be used to recirculate the solvent from the crystallization reactor unit 270 to the depolymerization reactor unit 210. In addition, the textile recycling system may include at least a distillation unit or an evaporator unit 290 or a combination thereof. The recirculation loop 280 may recirculate the solvent via at least the distillation unit 290 or the evaporator unit 290 or a combination thereof.

[0090] exist Figure 5 , a schematic cross-sectional view of one embodiment of a reactor unit 210 that may be used in the system 200 and method according to the present invention is shown. Figure 5 Existence and Figure 3 and Figure 4 Therefore, Figure 5 The focus of the related description will be on the reactor unit 210 .

[0091] The rotatable drum 220 may be further arranged inside a housing 235 of the reactor unit 210. The housing 235 may be arranged to maintain a desired pressure in the reactor unit 210. In addition, the housing 235 may be arranged to collect the solution discharged through the perforations 245 of the porous rotatable drum 220 and to separate the solution from the reactor unit 210. Figure 6 The perforation is further described together.

[0092] exist Figure 6 , a schematic diagram of an embodiment of a rotatable drum 220 according to the present invention is shown.

[0093] Preferably, the rotatable drum 220 is perforated with perforations 245. The perforations 245 enable the separation of the methanol-monomer solution from the remaining textile after the depolymerization reaction and possible subsequent steps, namely draining and centrifugal drying.

[0094] The perforations 245 of the rotatable drum 220 may be located in the shaft portion 246 of the rotatable drum 220. Furthermore, the perforations 245 may be located on at least one of its flat side portions 247. More preferably, the rotatable drum is provided with the perforations 245 in its shaft portion 246 and in at least one of its flat side portions 247. Still more preferably, the rotatable drum 220 includes the perforations 245 in its shaft portion 246 and in both of its flat side portions 247.

[0095] exist Figure 7, a schematic side view of an embodiment of a reactor unit 210 is shown. The reactor unit 210 comprises a pressure vessel 235. The heating device 230 is arranged as an example in the space between the pressure vessel 235 and the rotatable drum 220. For example, at least partially in the space between the housing 235 and the drum body 246 of the rotatable drum 220.

[0096] An axis coinciding with axis A extends into the reactor unit 210 to enable the rotation of the drum 220. For the purpose of rotating the drum 220, a motor (in Figure 7 (not shown) is connected to the shaft.

Claims

1. A method (100) of recycling at least a portion of a textile material comprising polyester fibers, the method comprising: - a mixing step (110), said mixing step (110) comprising contacting said textile material comprising polyester fibers and at least one other type of fibers with a suspension comprising a catalyst and methanol in a rotatable drum of a reactor unit, said rotatable drum being arranged to rotate about an axis (A) having an angle with a horizontal plane of less than 45°; a depolymerization step (120), said depolymerization step (120) comprising setting a temperature of at least 80° C. in said reactor unit, exposing said textile material to said catalyst and methanol to carry out a methanolysis depolymerization reaction of the polyester part of said textile material, while said other types of fibers remain in a fibrous state; wherein the drum is rotated during at least one of the mixing step and the depolymerization step so that the textile material tumbles inside the drum to contact the catalyst and methanol; as well as - discharging (130a) the liquid solution comprising the depolymerized polyester from the reactor unit, and discharging (130b) the fiber material comprising the other type of fibers from the reactor unit.

2. The method (100) according to claim 1, wherein during at least a part of the depolymerization step, the temperature in the reactor unit is set in the range of 100°C to 200°C, preferably in the range of 110°C to 180°C, more preferably in the range of 120°C to 170°C, most preferably in the range of 140°C to 170°C.

3. The method (100) according to claim 1 or 2, wherein during at least a part of the depolymerization step, the pressure in the reactor unit is maintained at at least 5 bar absolute, preferably at least 10 bar absolute, preferably the pressure is less than 40 bar absolute, for example less than 30 bar absolute, still more preferably the pressure is in the range of 10 to 25 bar absolute at least during a part of the depolymerization step, and / or wherein the rotatable drum is provided with perforations, preferably at least on the drum shell surface.

4. The method (100) according to any one of claims 1 to 3, wherein the at least one other fiber type of the textile material comprises cellulose-based fibers, preferably natural cellulose fibers such as cotton and linen and at least one of man-made cellulose fibers such as viscose, lyocell, rayon and modal, more preferably the at least one other fiber type comprises at least cotton.

5. The method (100) according to claim 4, wherein the textile material comprises at least 30% by weight, preferably at least 40% by weight, and more preferably at least 50% by weight of cellulose-based fibers, preferably the textile material comprises at least 30% by weight, preferably at least 40% by weight, and more preferably at least 50% by weight of cotton fibers, and more preferably the textile material comprises at least 30% by weight, more preferably at least 40% by weight, and more preferably at least 60% by weight of polyester-cotton composite textile material.

6. The method according to any one of claims 1 to 5, wherein the catalyst comprises Ca, preferably the catalyst comprises at least one of CaO, CaO-MgO and Ca(OH)2.

7. The process according to any one of claims 1 to 6, wherein the catalyst has a specific surface area of ​​at least 5 m 2 / g, preferably at least 10m 2 / g, more preferably at least 15m 2 / g, most preferably at least 20m 2 / g.

8. The method according to any one of claims 1 to 7, wherein the catalyst is present in an amount of 0.05 m / g of textile. 2 Up to 0.5m 2 The concentration is preferably 0.08 m / g of textile. 2 Up to 0.4m 2 The concentration was added.

9. The method (100) according to any one of claims 1 to 8, wherein the methanolysis depolymerization reaction is carried out in the reactor unit in an inert atmosphere, preferably in a N2 environment.

10. The method (100) according to any one of claims 1 to 9, wherein the method comprises at least one subsequent rinsing step (140) for rinsing the fiber material remaining after depolymerization of the polyester, preferably carried out in methanol charged to the reactor unit, preferably the rotatable drum is rotated during at least a part of the rinsing step, more preferably the method comprises a plurality of rinsing steps.

11. The method (100) according to claim 10, wherein the at least one washing step comprises centrifugal drying (140c) spinning means for separating methanol and depolymerized polyester from the fiber material.

12. A method (100) according to claim 10, wherein the at least one and initial flushing step (140) and any additional further flushing step (140) comprise a discharge (140a) before adding methanol to the reactor unit, or the flushing is performed after the discharge (140a) before adding methanol to the reactor unit, preferably the method comprises a discharge (140a) and several flushing (140b) steps in which methanol is added to the reactor unit, more preferably wherein the discharge (140a) is performed at a temperature in the range of 120°C to 160°C and the flushing (140b) is performed at a temperature in the range of 60°C to 200°C.

13. The method according to any one of claims 1 to 12, wherein the fiber material remaining in the rotatable drum (220) after depolymerization of the polyester is dried by applying a vacuum (125) to the reactor unit (210) to evaporate the methanol.

14. The method (100) according to any one of claims 1 to 13, wherein after the depolymerization step or the flushing step the catalyst and methanol solution is discharged through an outlet with a particle filter to filter out catalyst particles, preferably for further use.

15. The method (100) according to any one of claims 1 to 14, wherein after the step of discharging (130a) the liquid solution comprising the depolymerized polyester from the reactor unit, and optionally after any flushing step, the produced depolymerized polyester (DMT) is concentrated, cooled and crystallized (150) to achieve separation of the DMT and recycling and reuse of the methanol to the reactor unit, preferably the DMT is cooled and crystallized (150) in a separate crystallization reactor unit.

16. The method (100) of claim 15, wherein the methanol is recovered via at least one evaporation step or via distillation.

17. A textile recycling system (200) for recycling at least a portion of a textile material comprising polyester fibers, the system (200) being arranged to be suitable for performing a methanolysis depolymerization reaction of the polyester fibers and maintaining another type of fiber contained in the textile material in a fibrous state, the recycling system (200) comprising a depolymerization reactor unit (210), the depolymerization reactor unit (210) comprising a rotatable drum (220), the rotatable drum (220) being arranged to be suitable for rotation around an axis, the angle of the axis to the horizontal plane being less than 45°, and The depolymerization reactor unit (210) is a pressure vessel suitable for withstanding a temperature of at least 80°C, preferably a pressure of at least 5 bar, more preferably at least 10 bar.

18. The textile recovery system (200) according to claim 17, wherein during rotation of the rotatable drum (220), the angle of the shaft to the horizontal plane is less than 25°, preferably in the range of 0° to 10°.

19. The textile recycling system (200) according to claim 17 or 18, wherein the rotatable drum (220) is porous to enable separation of the methanol-monomer solution from the remaining textile after the depolymerization reaction and possible subsequent steps, the rotatable drum (220) being arranged inside a housing (235) of the reactor unit (210), the housing (235) being arranged to maintain a desired pressure in the reactor unit (210) and to collect the textile residues passing through the porous rotatable drum (220). 0), preferably, the rotatable drum (220) is provided with perforations (245) in its drum body (246) and / or in at least one of its flat side parts (247), more preferably, the rotatable drum is provided with perforations (245) in its drum body (246) and in at least one of its flat side parts (247), and even more preferably, the rotatable drum (220) includes perforations (245) in its drum body (246) and in both of its flat side parts (247).

20. A textile recycling system (200) according to any one of claims 17 to 19, wherein the textile recycling system (200) further comprises a separate charging device (240) for charging the reactor unit (210), and / or wherein the depolymerization reactor unit (210) comprises a heating device (230), preferably such a heating device (230) is arranged inside the shell (235) of the reactor unit (210), and more preferably the heating device (230) is at least partially arranged in the space between the shell (235) of the reactor unit (210) and the drum body (246) of the rotatable drum (220).

21. The textile recycling system (200) according to any one of claims 17 to 20, wherein the depolymerization reactor unit (210) is connected to an outlet (250) having a particle filter (260).

22. The textile recycling system (200) according to any one of claims 17 to 21, wherein the textile recycling system (200) further comprises a crystallization reactor unit (270) connected to the depolymerization reactor unit (210), preferably further comprising a recirculation loop (280) for recycling the solvent from the crystallization reactor unit (270) to the depolymerization reactor unit (210), preferably via at least an evaporator unit (290) or via a distillation unit (290) or a combination thereof.

23. A textile recycling system (200) according to any one of claims 17 to 22, wherein the textile recycling system (200) is arranged to rotate the rotatable drum (220) in a centrifugal drying mode for separating a solution comprising methanol and depolymerized polyester from the fiber material after the depolymerization step, and / or for separating methanol from the fiber material in a rinsing step, the rotatable drum being arranged to retain the fiber material inside the rotatable drum during such centrifugal drying, and being arranged to allow the solution to be released from the drum via perforations and collected in the housing (235) of the reactor unit and subsequently discharged via a discharge outlet.

24. The textile recycling system (200) according to any one of claims 17 to 23, wherein the textile recycling system (200) comprises a vacuum device for applying a vacuum to the reactor unit (210) for drying the fiber material retained in the rotatable drum (220) by evaporation of methanol.

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