NL2035177B1

NL2035177B1 - Method and arrangement for scouring fabric material

Info

Publication number: NL2035177B1
Application number: NL2035177A
Authority: NL
Inventors: Van Der Kraan Martijn
Original assignee: Dye Revolutions B V
Priority date: 2023-06-26
Filing date: 2023-06-26
Publication date: 2025-01-07
Also published as: WO2025005796A1

Abstract

Method for scouring fabric material using carbon dioxide, comprising the steps of: - providing a fabric material having one or more contaminants, for example a lubricant, on a textile beam in a treatment vessel; - introducing liquid carbon dioxide in the treatment vessel via an opening, thereby dissolving at least a part of the contamination in the liquid carbon dioxide; - expelling the liquid carbon dioxide from the treatment vessel to a separator provided downstream of and in ﬂuid communication with the treatment vessel using an expellant; and - heating the liquid carbon dioxide in the separator to a temperature above the boiling point of carbon dioxide and below the boiling point of the one or more contaminants, thereby creating gaseous carbon dioxide and a non-gaseous contaminant phase. Fig. 1

Description

P135085NL00

Title: Method and arrangement for scouring fabric material

The invention relates to a method for scouring fabric material and an arrangement for use in said method.

In addition to dyeing in water, various methods for coloration of fabric textile on an industrial scale are well known in the state of the art.

Examples of such methods are dope dyeing, supercritical CO2 dyeing and textile printing.

Dope dyeing, also known as solution dyeing or mass pigmentation, is a method of coloring synthetic fibers during their manufacturing process.

In this technique, the color pigments are added to the polymer solution before the fibers are formed, resulting in a uniformly colored fiber throughout its entire cross-section.

Supercritical CO2 dyeing is used to dye fabrics using carbon dioxide (CO2), instead of water, to transport the dyes to the fibers. In this process, CO2 1s subjected to high temperature and pressure, causing it to reach a supercritical state where it exhibits properties of both a liquid and a gas, making it a good solvent for the dyes.

Textile printing is a process of applying decorative or functional designs onto fabrics or textile materials. It involves the transfer of color or patterns onto the surface of the fabric using various printing techniques and methods.

During production of fabrics, contaminants, such as oils, waxes and/or lubricants, may attach to the surface of the fabric. Contaminants may negatively affect further manufacturing steps and therefore should be removed from the fabric. Specifically, if the contaminants are present before dyeing, they may prevent dye from attaching or attaching evenly to the surface of the fabric material. The removal of contaminants is called scouring. Besides the removal of contaminants, scouring may improve absorption properties to the fabric, as the removal of substances like oils or waxes may result in a decreased surface tension of the fabric, allowing better dye absorption and a more uniform dye distribution. Scouring is commonly done using an alkaline solution and detergents.

A disadvantage of scouring is the high energy and water consumption, the environmental impact and potentially the high labor intensity. When using an alkaline solution and a detergent, wastewater from the scouring process needs to be treated, e.g. cleaned, before it can be released to open water. Treating of wastewater can be a costly operation, and has a significant carbon footprint. Additionally, conventional scouring processes are done at high temperatures and require extended treatment times, which can contribute to a high energy consumption. Significant amounts of water are needed to rinse the fabric once the scouring has finished.

The invention aims to counteract the above disadvantages, preferably while retaining the advantages. More specifically, the invention aims to provide a method of scouring fabric material that 1s more energy and water efficient, and may have a lower impact on the environment.

Therefore, the invention provides for a method for scouring fabric material using carbon dioxide, in particular a method according to claim 1.

The method comprises the step of providing a fabric material having one or more contaminants, preferably a lubricant, on a textile beam in a treatment vessel. The method further comprises the step of introducing liquid carbon dioxide in the treatment vessel via an opening, thereby dissolving at least a part of the contamination in the liquid carbon dioxide. Optionally, the method comprises an extra step of recirculating the liquid carbon dioxide through the textile and a recirculation pump, to allow more contaminant to dissolve in the carbon dioxide. Optionally, the method comprises the step of expelling, or otherwise transporting, the liquid carbon dioxide with the dissolved contaminant, from the treatment vessel to a separator provided downstream of and in fluid communication, preferably via a control valve,

with the treatment vessel using a gaseous carbon dioxide or a supercritical carbon dioxide as expellant. Finally, the method comprises the step of heating the liquid carbon dioxide in the separator to a temperature above the boiling point of carbon dioxide and below the boiling point of the one or more contaminants, thereby creating gaseous carbon dioxide and a non- gaseous contaminant phase.

In the context of the invention, the phrase “dissolving at least a part of the contamination in the liquid carbon dioxide” should be understood as dissolving a noticeable amount of contamination in the liquid carbon dioxide. For example, a noticeable amount could be expressed in a weight percentage of the weight of the contaminant. In this case, “dissolving at least a part” should be understood as dissolving more than 10 wt% of the contaminant in the liquid carbon dioxide, such as 20 wt%, preferably more than 30 wt%, more preferably more than 60 wt%, and even more preferably more than 80 wt% such as 90 wt%.

The provided fabric material may be provided as knitted or woven textile. The knitted or woven textile may be made from synthetic fibers, e.g. polyester, spandex, nylon or acrylic, natural fibers, e.g. cotton, linen and silk, or a blended fabric, i.e. a combination of different fibers.

Contamination on the surface of the fabric material may be oils, waxes, lubricants or any other unwanted product. These contaminations may attach to the surface by accident, e.g. by mishandling, or dropping, the fabric material. Alternatively, contaminations may attach to the surface during preceding production steps of the textile production process. For example, lubricants may be provided on the surface of the textiles in preceding production steps in order to facilitate handling and production such as during spinning, weaving, or knitting. Lubricants may interfere with the dyeing or printing of the fabric material, and should be at least substantially removed by scouring.

The textile beam is commonly a cylindrical or roller-shaped component. The fabric is wound around the textile beam to create a roll, allowing for efficient processing of large quantities of fabric, i.e. weight per volume (e.g. kg/m3). Textile beams may come in different sizes and configurations to accommodate various fabric widths, weights and production requirements.

The treatment vessel used is a pressure vessel designed to hold and contain liquid carbon dioxide. The treatment vessel may be constructed from materials that can withstand high-pressure conditions during operation, such as stainless steel. Inside the vessel, there may be a mounting arrangement to releasable mount the textile beam to the vessel such that, when a fabric material is provided on the textile beam, the fabric material is not in contact with the walls of the treatment vessel. The treatment vessel may contain any number of nozzles in order to provide an opening for a fluid connection to additional process equipment provided up- and/or downstream of the treatment vessel.

The liquid carbon dioxide present in the treatment vessel during use, containing the contaminated liquid carbon dioxide, may be expelled using an expellant after a period of time, such as a recirculation time.

Preferably, the period of time is a predetermined period of time, after which the liquid carbon dioxide has removed, e.g. by dissolving, a substantial amount of the contaminant from the surface of the fabric material. The predetermined period of recirculation time can be determined based on experiments, and may depend on the type of fabric material and contaminants present in the treatment vessel. Expelling the liquid carbon dioxide 1s done by introducing carbon dioxide in a gaseous or supercritical phase, thereby forcing the liquid carbon dioxide out of the treatment vessel.

The liquid carbon dioxide is transported to the separator provided downstream of the treatment vessel. Once the expelling of the liquid carbon dioxide is complete, most, if not all, of the liquid carbon dioxide has been removed from the treatment vessel. What remains in the treatment vessel is the fabric material, that has been scoured, and gaseous or supereritical carbon dioxide. While gaseous or supercritical carbon dioxide is preferred other, preferably inert, gases can be used as an expellant, such as for 5 example nitrogen.

In the separator, the liquid carbon dioxide is evaporated and the less-volatile contaminants precipitate as a solid or a liquid and remain in the separator. This allows for the separation of the carbon dioxide and the contaminants. The contaminants may be recovered from the separator.

Recovering contaminants may further reduce the environmental impact of fabric material production, as it may be prevented that the contaminants need to be treated in a wastewater treatment facility or that the contaminants are discarded in the environment.

The removed non-gaseous contaminant phase, i.e. the recovered contaminants, may be collected and stored in one or more auxiliary storage vessels. Optionally, the recovered contaminants may be filtered or otherwise purified to increase their value. Preferably, the recovered contaminants that have been stored in the one or more auxiliary storage vessels have a purity of at least 50%, more preferably at least 70%, even more preferably at least 90%. The recovered contaminants, in particular oil, wax or other lubricants, may be reused as a lubricant for other fabric material production steps. For example, recovered oil may be reused as spinning or knitting oil.

Additionally, or alternatively, the recovered oil may be sold to a third party.

The method may further comprise recovering and condensing the gaseous carbon dioxide in a condenser provided downstream of and in fluid communication with the separator and providing the recovered Liquid carbon dioxide to a storage vessel provided downstream of, and in fluid communication, with the condenser. The gaseous carbon dioxide may be condensed by reducing the temperature of the carbon dioxide.

Liquid carbon dioxide introduced in the treatment vessel via the opening can be supplied from the storage vessel. This may facilitate a circulation cycle, allowing the carbon dioxide used for scouring to be reused again as a liquid carbon dioxide or expellant. This may vastly reduce the environmental impact as most of the scouring material, i.e. the liquid carbon dioxide, 1s not released to the environment.

Additionally, or alternatively, the non-gaseous contaminant phase may be removed from the separator. The non-gaseous contaminants may be reused or be discarded with minimal impact on the environment. In particular, reuse of recovered lubricant may be highly advantageous. The recovered lubricant may under go a purification step, e.g. a filtering, before it 1s reused in another step of the fabric material production process, e.g. knitting.

At least one of the liquid carbon dioxide and the expellant can be introduced in the treatment vessel via openings in the textile beam. The textile beam, may be used afterwards in different production steps such as dyeing. Since there is no need to unwind the scoured fabric material from the textile beam, and wind it on an auxiliary textile beam, the amount of labor may be reduced as well as the total production time.

The liquid carbon dioxide and the contaminated liquid carbon dioxide in the treatment vessel can be kept at a temperature in a range of 10 - 30 degrees Celsius. Additionally, or alternatively, the pressure inside the treatment vessel can be in a range of 50 - 70 bar. This is considered an energy efficient condition that maximizes the scouring capability by providing a liquid carbon dioxide, without the need of significant amounts of temperature control, i.e. heating and / or cooling, while keeping the pressures also relatively low, i.e. in the range of < 100 bar.

The method may further comprise depressurizing the treatment vessel once the liquid carbon dioxide is substantially expelled from the treatment vessel. Preferably, a gas booster or compressor is provided downstream of the treatment vessel. The gas booster or compressor may be arranged to draw the expellant from the treatment vessel and provide the expellant to the separator or the storage vessel directly, thereby significantly depressurizing the treatment vessel. When the pressure in the treatment vessel is sufficiently low, for example 5 bar, the treatment vessel may be depressurized further by venting directly to the outside for example by using a vent, thereby releasing the remaining expellant into the atmosphere.

Additionally or alternatively, the method may further comprise the step of recirculating the liquid carbon dioxide present in the treatment vessel, preferably via a recirculation loop comprising a recirculation pump.

Recirculating the liquid carbon dioxide may in particular be relevant during the scouring process as it may provide a flow of liquid COQ2 past the contaminated fibers, thus facilitating the dissolution of contaminant in the liquid carbon dioxide.

In a second aspect, the invention relates to an arrangement for scouring fabric material. Said arrangement comprises a treatment vessel and a textile beam. The textile beam 1s arranged to be releasably mounted on the inside of the treatment vessel. The arrangement further comprises a carbon dioxide circuit arranged to provide liquid carbon dioxide, via a pump, into the treatment vessel via openings in the textile beam. The carbon dioxide circuit is further arranged to introduce an expellant, preferably carbon dioxide gas or supercritical carbon dioxide, into the treatment vessel.

The carbon dioxide circuit is arranged to recover, preferably most of, the liquid carbon dioxide and the expellant for reuse.

The expellant may be introduced into the treatment vessel via the openings in the textile beam.

The arrangement for scouring fabric material may further comprise a recirculation loop arranged to recirculate liquid carbon dioxide vla a recirculation pump into the treatment vessel. In a special embodiment,

the pump of the carbon dioxide circuit and the recirculation pump of the recirculation circuit may be the same pump. In a further embodiment, the recirculation pump may be provided in the treatment vessel.

Further advantageous aspects of the invention are set out in the description and appended claims.

The technical features described in the paragraphs and sentences above can be isolated from the context, and the isolated technical features from the different paragraphs and sentences can be combined. Such combinations are herewith specifically disclosed in this description.

The invention will further be elucidated on the basis of exemplary embodiments which are represented in the drawings. The exemplary embodiments are given by way of non-limitative illustration of the invention.

In the drawings:

Fig. 1 shows a schematic cross-section of a treatment vessel in which a textile beam with a fabric material has been mounted;

Fig. 2 shows a PFD of an arrangement for scouring fabric material;

Fig. 3 shows a PFD of an alternative arrangement for scouring fabric material.

It is noted that the figures are only schematic representations that are given by way of non-limiting examples. In the figures, the same or corresponding parts are designated with the same reference numerals.

A cross-sectional side view of an example of a treatment vessel 10 has been depicted. The treatment vessel 10 comprises a wall 15 with multiple nozzles 16 provided thereon that are in fluid communication, preferable via a conduit that comprises a control valve, with further process equipment provided upstream / downstream of the treatment vessel 10, e.g. such as the separator 20. Three nozzles have been depicted, however it will be clear to the person skilled in the art that any number of nozzles may be provided in order to facilitate the scouring process. In the example, nozzle 16’ allows treatment vessel 10 to be in fluid communication, preferably via a control valve, with separator 20. This nozzle 16’ is provided at a bottom side of the treatment vessel 10 as introducing the expellant in the treatment vessel 10 will force the heavier liquid carbon dioxide in a downward direction. In the treatment vessel 10, a hollow textile beam 12 has been depicted. The textile beam 12 has a closed-off end 18 and comprises a plurality of, preferably evenly spaced, openings 13. The textile beam 12 is arranged to be releasably liquid tight mounted on the inside of the treatment vessel 10 to a wall 15. A fluid or gas can be introduced into the hollow textile beam 12 via opening 17. Opening 17 is provided in both the treatment vessel 10 and the textile beam 12 and are aligned once the textile beam 12 is mounted to the wall 15 of the pressure vessel 10. Around the textile beam, a fabric material 14 has been wound. As a result, fluid or gas can be introduced into the textile beam 12 via opening 17, which can flow out of the hollow textile beam 12 via openings 13, thereby passing through the fabric material, and entering the space between the wall 15 and fabric material 14 in the treatment vessel 10.

Turning to Fig. 2, a process-flow diagram (PFD) of an example of an arrangement for scouring fabric material, comprising a carbon dioxide circuit A and a recirculation loop B. The carbon dioxide circuit A comprises a separator 20, a condenser 30, a storage vessel 40, a chiller 50, a pump 60, a heater 70 and conduits, e.g. piping, connecting the components. In the example, a recirculation pump 11 is provided, arranged to recycle the fluid present in the treatment vessel 10 in a recirculation loop B via connecting conduits, e.g. piping. Recirculating the liquid carbon dioxide may in particular be relevant during the scouring process as it may provide for movement of the liquid carbon dioxide relative to the contaminant on the fibers, thus enabling faster dissolution of contaminant into the liquid.

Without recirculation, the dissolution process may be too slow or may result in an uneven removal of contaminant from fiber.

Additionally, or alternatively, the recirculation pump 60 may be provided in the treatment vessel 10. This way, there is no need to provide for a conduit, e.g. piping, leading from the treatment vessel 10 to the recirculation pump 60 and from the recirculation pump to the treatment vessel 10.

Referring to Fig. 3, as an alternative embodiment pump 60 can be used as a recirculation pump. This may be provided by providing a different process layout, in which both the carbon dioxide circuit A and the recirculation loop both connect to the inlet and outlet of pump 60. In this embodiment, it is preferred that the recirculation loop B and carbon dioxide circuit A can be separated, for example via valves, such that only the loop or circuit is active at a time without affecting the other. This embodiment may be advantageous as only one pump is needed instead of two.

The treatment vessel 10 is in fluid communication with a separator 20 provided downstream. The liquid carbon dioxide that contains contaminants may be heated in the separator 20. When the liquid carbon dioxide is heated above the boiling point of the liquid carbon dioxide at operating conditions, e.g. 50-70 bar, but below the boiling point of the contaminants at operating conditions, carbon dioxide evaporates from boiling carbon dioxide in the separator, where the liquid phase becomes supersaturated and the contaminants precipitate as a liquid and / or solid.

The contaminants may then be drained or otherwise removed from the carbon dioxide circuit A, for example using drain 21. The evaporated carbon dioxide can be provided to a condenser 30 provided downstream and in fluid communication with the separator 20, for example via a conduit in the top of the separator 20.

The evaporated, gaseous carbon dioxide is condensed in the condenser 30, for example by cooling the carbon dioxide. The liquid carbon dioxide formed in the condenser 30 can then be collected in a storage vessel 40. The storage vessel 40 acts as a buffer and storage tank for carbon dioxide that can be used for the scouring process. The storage vessel 40 is in fluid communication with an optional chiller 50, which is provided downstream and in fluid communication with the storage vessel 40. The chiller 50 is arranged to cool the liquid carbon dioxide such that the Liquid carbon dioxide is subcooled once entering the pump 60, thereby reducing the risk of cavitation in pump 60. The pump 60 is provided downstream and in fluid communication with the chiller 50. The heater 70 is provided downstream and in fluid communication with the pump 60. The pump 60 is preferably arranged to pressurize the liquid carbon dioxide to a range between 50 and 70 bar. In order to use the pressurized liquid carbon dioxide as an expellant, the pressurized liquid carbon dioxide may be heated to either the gaseous or the supercritical phase using the heater 70.

In an example of using the arrangement of Fig. 2 to scour fabric material, the following process using gaseous carbon dioxide as an expellant may be observed. First, a fabric material that has contaminants on its surface is wound on a textile beam 12 and mounted in the treatment vessel 10, after which the treatment vessel 10 is liquid tightly closed. Afterwards, liquid carbon dioxide is supplied from the storage vessel 40, via chiller 50, pump 60 and heater 70 to the treatment vessel 10, via openings 16, 16° or 17 in the treatment vessel wall. In the filling stage, heater 70 is not used, or, in an alternative embodiment, bypassed by the liquid carbon dioxide. Once the treatment vessel 10 is filled with liquid carbon dioxide, the recirculation pump 11 may be switched on to recirculate the liquid carbon dioxide through loop B, i.e. consecutively through the treatment vessel wall opening 17, the inside of the beam, the beam openings 13, the textile material 14, the space between the textile and the inside of the treatment vessel wall, out through one or more openings 16 and/or 16° in the treatment vessel wall and back to the recirculation pump 11 The recirculation stage brings about contact between solvent (liquid carbon dioxide) and oil, facilitating the dissolution of the latter into the former. Next, carbon dioxide is supplied from the storage vessel 40 through chiller 50, and is brought in to a gaseous or supercritical phase by heater 70. The heated gaseous or supercritical carbon dioxide 1s introduced into the treatment vessel 10, acting as an expellant forcing the liquid carbon dioxide with contaminants to the separator 20. Once a substantial amount of liquid carbon dioxide is expelled from the treatment vessel 10, the treatment vessel 10 can be depressurized.

In the separator 20, the liquid carbon dioxide can be evaporated, allowing it to be collected in the storage vessel 40 after it has been condensed in the condenser 30. The contaminants, which have not been evaporated, may be removed via drain 21 provided at the bottom of the separator 20 and collected in an auxiliary storage vessel (not depicted).

Many variations will be apparent to the skilled person in the art.

Such variations are understood to be comprised within the scope of the invention as defined in the appended claims.

Claims

Conclusions

1. A method for cleaning a dust material using carbon dioxide, comprising the steps of: - providing a dust material having one or more contaminants, for example a lubricant, on a fabric bar in a treatment vessel; - introducing liquid carbon dioxide into the treatment vessel through an opening whereby at least a portion of the one or more contaminants is dissolved in the liquid carbon dioxide; - expelling the liquid carbon dioxide from the treatment vessel to a separator provided downstream of and in fluid communication with the treatment vessel using an expelling means; and - heating the liquid carbon dioxide in the separator to a temperature above the boiling point of carbon dioxide and below the boiling point of the one or more contaminants, thereby forming a gaseous carbon dioxide and a non-gaseous contaminant phase.

2. A method of cleaning dust material according to claim 1, further comprising: - recovering and condensing the gaseous carbon dioxide in a condenser provided downstream of and in fluid communication with the separator and circulating the recovered liquid carbon dioxide to a storage vessel provided downstream of and in fluid communication with the condenser; and - removing the non-gaseous contaminant phase from the separator; wherein the liquid carbon dioxide introduced into the treatment vessel is supplied from the storage vessel.

3. A method of cleaning dust material according to claim 2, wherein the removed non-gaseous contamination phase is collected and stored in one or more auxiliary storage vessels.

4. A method of cleaning fabric material according to any preceding claim, wherein the liquid carbon dioxide is introduced into the treatment vessel through openings in the fabric bar.

5. A method of cleaning fabric material according to any preceding claim, wherein the expelling agent is introduced into the treatment vessel through openings in the fabric bar.

6. A method for cleaning dust material according to any preceding claim, wherein a temperature of the liquid carbon dioxide in the treatment vessel is maintained at a temperature in a range of 10 - 30 degrees Celsius during the presence of liquid carbon dioxide in the treatment vessel.

7. A method for cleaning dust material according to any preceding claim, wherein the pressure in the treatment vessel is in a range of 50 - 70 bar at least during the presence of liquid carbon dioxide in the treatment vessel.

8. A method for cleaning dust material according to any preceding claim, further comprising: - depressurizing the treatment vessel when the liquid carbon dioxide has been substantially expelled from the treatment vessel.

9. A method for cleaning dust material according to any preceding claim, further comprising the step of circulating liquid carbon dioxide present in the treatment vessel, preferably via a recirculation loop comprising a circulation pump.

10. A method for cleaning dust material according to any preceding claim, wherein the propellant is a gaseous carbon dioxide.

11. A method for cleaning dust material according to any one of claims 1 to 9, wherein the propellant is supercritical carbon dioxide.

12. Apparatus for cleaning dust material comprising: - a treatment vessel and a textile bar, the textile bar being adapted to be releasably attached to the inside of the treatment vessel; and - a carbon dioxide circuit adapted to provide liquid carbon dioxide via a pump into the treatment vessel through openings in the textile bar; the carbon dioxide circuit being further adapted to introduce a propellant, for example carbon dioxide, into the treatment vessel; and the carbon dioxide circuit being adapted to substantially recover the liquid carbon dioxide for reuse.

13. An apparatus for cleaning fabric material according to claim 12, wherein the carbon dioxide circuit is further configured to introduce the propellant into the treatment vessel through the openings in the fabric bar.

14. Apparatus for cleaning fabric material according to claim 12 or 13, wherein the carbon dioxide circuit is arranged to substantially recover the whitening agent for reuse.

15. Apparatus for cleaning dust material according to any one of claims 12 to 14, further comprising a recirculation loop adapted to recirculate liquid carbon dioxide from the treatment vessel back into the treatment vessel via a recirculation pump.

16. Apparatus for cleaning dust material according to claim 15, wherein the pump of the carbon dioxide circuit and the recirculation pump of the recirculation loop are the same pump.

17. Apparatus for cleaning dust material according to claim 16, wherein the recirculation pump is provided in the treatment vessel.

18. Apparatus for cleaning dust material according to any one of claims 12 to 17, further comprising carbon dioxide in the carbon dioxide circuit and in the treatment vessel.

19. A device for cleaning dust material according to any one of claims 12 to 18, wherein the propellant is a gaseous carbon dioxide.

20. Apparatus for cleaning dust material according to any one of claims 12 to 18, wherein the propellant is a supercritical carbon dioxide.