Use of fibers from cigarette butts for the manufacture of thermal and / or acoustic insulation, filters and / or biodegradable plastic objects

Abstract

The present invention relates to the use of fibers from cigarette butt filters for the manufacture of thermal and / or acoustic insulation, filters and / or biodegradable plastic objects, said fibers preferably being cellulose acetate fibers.

Description

Title of the invention: Use of fibers from cigarette butts for the manufacture of thermal and / or acoustic insulation, filters, and / or biodegradable plastic objects. Technical field

[0001] The present invention relates to the field of cigarette butt cleaning, and more particularly to the cleaning and decontamination of fibers from cigarette butt filters.

[0002] One of the objectives of the present invention is to reduce the impact of cigarette butts on the environment by cleaning / depolluting the fibers from cigarette butts and by valorizing these fibers by manufacturing eco-designed products.

[0003] The object of the present invention thus relates to a cleaning process and installation using supercritical fluid technology to decontaminate fibers from cigarette butt filters.

[0004] The object of the present invention also relates to the recycling and reuse of the decontaminated fibers obtained after such cleaning.

[0005] The present invention will find numerous advantageous applications by offering both industry and communities a simple and environmentally friendly technology for the depollution of cigarette butts. Prior art

[0006] Recycling cigarette butts has become a real ecological and environmental issue.

[0007] Cigarette butts are indeed one of the most important types of waste in the world, with more than four billion cigarette butts thrown into nature every year; this represents, for example, almost 40% of the waste found in the oceans.

[0008] It should be noted here that a cigarette butt decomposes in nature after approximately 15 years; during this period, the cigarette butt alone pollutes up to 500 liters of water. Despite these alarming figures, the Applicant observes that very few resources have been deployed to date for the implementation of cigarette butt recycling, for technical, financial, and / or ecological / environmental reasons.

[0009] We are familiar with document FR 17 54267 Al, which deals with the recycling of cigarette butts. In this document, recycling includes a cleaning step essentially based on water.

[0010] US patent 5504119 A is also known, which relates to the recycling of waste from cigarette manufacturing; in this patent, a water-based cleaning step is also used.

[0011] The decontamination of cigarette butts involving water-based cleaning (by soaking, spraying, wiping, etc.) necessarily requires an additional step of treatment and filtration of the polluted water that was used for cleaning.

[0012] This makes the process costly and tedious.

[0013] The Applicant further submits that certain toxic substances present in cigarette butts cannot dissolve in water, so the performance associated with this type of technology is not satisfactory.

[0014] Other technologies are proposed for the recycling of cigarette butts such as for example that proposed in document WO 2019167054 Al which proposes a recycling of cigarette butts using natural absorbents such as for example earth to clean the fibre of cigarette butts and manufacture sanitary tampons; such a document aims mainly to improve sanitary conditions in disadvantaged countries.

[0015] On the other hand, the technical teaching of this document does not apply to the cleaning and depollution of cigarette butts.

[0016] The Applicant submits, after extensive research on the subject, that there is currently no reliable and efficient solution that ensures large-scale and cost-effective cleaning and decontamination of cigarette butts in order to recycle the fibers, particularly cellulose acetate fibers. Summary of the invention

[0017] The present invention aims to improve the situation described above.

[0018] The present invention is more particularly aimed at remedying at least one of the various disadvantages mentioned above by proposing an innovative cleaning and depollution technique implementing contact between said cigarette butts and a dense fluid under pressure, and in particular a fluid in a supercritical state.

[0019] To this end, the object of the present invention relates in a first aspect to a method for cleaning cigarette butts comprising the following steps: - a treatment of the cigarette butts to extract fibers to be decontaminated; and - a decontamination of the fibers to be decontaminated by bringing them into contact with a dense fluid under pressure, preferably a fluid in a supercritical state, called a supercritical fluid.

[0020] Bringing a dense fluid under pressure, preferably a supercritical fluid, into contact with the fibers to be cleaned makes it possible to extract from said fibers a very the vast majority, if not all, of the toxic substances and odors accumulated in cigarette filters.

[0021] The dense fluid under pressure (preferably a fluid brought to a supercritical state) acts as a powerful solvent, particularly for organic compounds including contaminants and pollutants.

[0022] Such extraction of toxic substances and odors accumulated in cigarette filters by a dense fluid under pressure technology (and in particular supercritical fluid) allows for the depollution of the fibers; after depollution, these fibers become clean and are suitable for reuse for new materials and / or other applications.

[0023] Such depolluted fibres are appreciated in particular for their thermal and / or acoustic properties, their filtering capacities and / or their mechanical properties.

[0024] The use of a dense fluid under pressure or a supercritical fluid is advantageous in that it does not require any post-treatment after depollution, unlike water-based cleaning techniques which require treatment of the contaminated cleaning water.

[0025] The decontaminated cigarette butt fiber can then be transformed into semi-finished or finished products in various forms, becoming an eco-designed material usable in several fields. It will be understood that, depending on the field of application, the level of cleaning and purification of the fiber may vary according to the requirements and standards applied to those fields.

[0026] In an advantageous embodiment, the process according to the present invention includes an initial cigarette butt collection phase during which cigarette butts are collected.

[0027] Such collection can be carried out by individuals, associations, communities, companies and / or manufacturers, in particular manufacturers operating in the field of cigarette manufacturing.

[0028] Such a collection can therefore be organised at both the local and national levels.

[0029] Advantageously, cigarette butt fibers include cellulose acetate fibers. The reuse of these cellulose acetate fibers, once decontaminated, is valued for applications such as: - textile clothing items (insulating coat padding, insulating quilting, sewing threads, fabrics, wool for use in the creation of clothes or textile-based objects: mattresses, cushions, duvets, hats, head coverings, handbags...); - thermal and / or acoustic insulation materials (building, electronics, automotive: lithium battery insulation for electric vehicles, aeronautics, shipbuilding, etc.); - filtering materials (liquid, gas, etc.) in the form of fibrous sheets or loose fibers conforming to the standards of the field of use.

[0030] It is also appreciated in the field of plastics processing in order to create new eco-designed solid materials with or without mixture.

[0031] In an advantageous embodiment, the fibers to be cleaned are introduced into a cleaning chamber. This is preferably carried out during the cleaning phase before contact.

[0032] Preferably, such a chamber is in the form of a closed enclosure such as, for example, an autoclave.

[0033] Advantageously, during the depollution phase, the fluid is compressed to a determined pressure called supercritical and is heated to a temperature called supercritical, said supercritical pressure and temperature being determined according to the fluid.

[0034] Preferably, the supercritical pressure is between 0 and 2000 bars, preferably between 50 and 350 bars, preferably between 280 and 320 bars.

[0035] Preferably, the supercritical temperature is between 0° and 400° Celsius, preferably between 15° and 80° Celsius.

[0036] One aspect of the present invention is thus to provide effective depollution by adjusting in particular the pressure and temperature parameters in order to bring the fluid into a supercritical state sufficiently powerful and solvent to eliminate (extract) the toxic substances and odors present in the cigarette fibers, after combustion of the tobacco.

[0037] The extraction performance of the substances depends on the intended applications for the fiber. It will be understood that the parameters associated with pressure and temperature will likely change depending on the required fiber purity levels.

[0038] Advantageously, the fluid is selected from: carbon dioxide; certain organic liquids such as methanol or ethanol; water; tetrafluoroethane; light alkanes, such as, for example, methane, propane, butane, isobutane and pentane; dihydrogen monoxide; alkenes such as ethylene and propylene.

[0039] All these fluids can be used in the state of dense fluid under pressure, in the subcritical state (wet oxidation) or supercritical state.

[0040] In an advantageous embodiment of the present invention, the fluid selected for the pollution control phase is carbon dioxide. It is planned to preferably that, in this mode, the supercritical temperature is greater than or equal to 31° Celsius and the supercritical pressure is greater than or equal to 73.85 bars.

[0041] The use of carbon dioxide as a fluid is advantageous in that it makes it possible to depollute a waste such as a cigarette butt using another waste emitted in very large quantities by industries (carbon dioxide).

[0042] The temperature (temperature greater than or equal to 31° Celsius) and pressure (pressure greater than or equal to 73.85 bars) conditions for bringing the dioxide to the supercritical state are satisfactory and can be achieved without difficulty in an enclosure such as an autoclave.

[0043] Obviously, a person skilled in the art will be able to select other fluids and / or other pressure and / or temperature parameters for this depollution operation.

[0044] It is understood here that the degree of extraction and the transport capacities of the fluid can vary by acting on these temperature and pressure parameters. Through this technology, a solubilizing fluid with adjustable power is obtained, particularly for contaminants to be extracted from the fiber produced by the filter.

[0045] Advantageously, a co-solvent is added to the fluid to extract unwanted organic substances from the fibers, while preserving the quality and technical characteristics of the fiber.

[0046] The addition of such a co-solvent makes it possible to remove certain organic substances present in the fibers in order to improve the cleaning process.

[0047] It will be understood that this addition of co-solvent can be carried out before, during and / or after the contact of the fluid with the fibers to be decontaminated.

[0048] Advantageously, the co-solvent is selected from: dihydrogen monoxide; alcohols, for example aliphatic alcohols, such as ethanol, methanol, butanol; aqueous solutions (for example water); terpenes; benzene; cyclohexanes and their mixtures; ketones; hydrofluoroethers and all other co-solvents capable of removing undesirable substances present in the fiber.

[0049] Advantageously, an extractant is added to the fluid to extract inorganic substances such as heavy metals from the fibers.

[0050] The addition of such an extractant makes it possible to remove certain inorganic substances present in the fibers in order to improve the performance of the depollution phase.

[0051] It will be understood that this addition of extractant can be carried out before, during and / or after the contact of the fluid with the fibers to be decontaminated.

[0052] Preferably, the extractant comprises a range of calixarene-type molecules and / or solutions of agents capable of extracting inorganic substances (complexants, chelators, antioxidants, buffer solutions).

[0053] The addition of cosolvent(s) can also have an impact on inorganic molecules, and conversely, the addition of extractant(s) can also have an impact on organic molecules.

[0054] It will be understood that the co-solvents and extractants are chosen according to the undesirable substances to be extracted, according to the standards corresponding to the markets.

[0055] Indeed, depending on the market outlets, the desired fiber purity results may vary.

[0056] Thus, the parameters (pressure, temperature, flow rate, cleaning time, etc.) as well as the use or not of co-solvents and / or extractants can vary according to the desired results.

[0057] Advantageously, the decontamination step includes, prior to contacting, a humidification of the fibers.

[0058] Other parameters associated with the contact of the dense fluid under pressure (for example a supercritical fluid) can be considered: flow rate and / or velocity of the fluid, duration of contact, etc.

[0059] Advantageously, the contacting includes an action of a jet of fluid towards the fibers.

[0060] Preferably, the jet has a speed between 1 and 500 meters per second.

[0061] Preferably, the jet comprises a flow rate of between 1 and 4000 litres per hour.

[0062] Preferably, the contact is made for a duration between one minute and eight o'clock.

[0063] The flow rate and duration of the cleaning can therefore vary, in particular depending on the quantity of material to be treated, the parameters and the substances targeted.

[0064] It is also possible to provide, for example, for the rotation of the fibers in a rotating drum inside the cleaning chamber.

[0065] Pressure variations can still be predicted according to compression and depression cycles.

[0066] More broadly, it can be expected during the cleaning cycle that the pressure, temperature and flow rate of the fluid are likely to remain constant or vary.

[0067] Advantageously, the treatment phase includes grinding the cigarette butts.

[0068] Preferably, such grinding is carried out for example in a grinder or a so-called treatment tank after a collection phase and possibly a sorting operation.

[0069] The crushed cigarette butts are then conveyed onto a production line to undergo a plurality of processing operations (friction and / or sieving and / or cycloning and / or secondary grinding).

[0070] Advantageously, the treatment phase includes, in particular, sieving.

[0071] This or these different operations are mainly aimed at separating the fibers from the others waste, the other waste being of the type leaves, ashes and / or tobacco.

[0072] Only the fiber consisting partly of cellulose acetate is recovered. Preferably, the other waste (leaves, tobacco, ash) is recycled in the form of compost.

[0073] These treatment operations can be carried out in a treatment tank adapted for this purpose; this tank can be independent of the autoclave or possibly be directly integrated into the autoclave.

[0074] The object of the present invention relates, according to a second aspect, to a cleaned (or decontaminated) fibre obtained as a result of implementing a cleaning process such as that described above.

[0075] Such a decontaminated fiber can be reused for many applications, particularly in the building, clothing and any other field that can exploit this fiber.

[0076] The object of the present invention relates, according to a third aspect, to a cigarette butt cleaning installation comprising: - a treatment tank configured to process cigarette butts in order to extract fibers for decontamination; and - means of decontamination configured to decontaminate the fibres by bringing them into contact with a dense fluid under pressure (preferably a fluid in a supercritical state, called a supercritical fluid).

[0077] In a preferred embodiment, the depollution means comprising one or more autoclave-type cleaning chambers.

[0078] Preferably, such an autoclave is capable of withstanding high or even very high pressures.

[0079] The chamber capacity can, for example, vary from 0.2L to 1500L, however, it is not limited.

[0080] Advantageously, the installation includes means such as nozzles, pipes and / or valves for injecting the supercritical fluid into the chamber(s).

[0081] Advantageously, the chamber can extend vertically or horizontally.

[0082] It should be noted that the vertical inclination of the chamber facilitates loading / unloading and ensures good propagation of the fluid (carbon dioxide) in the fibers to be decontaminated.

[0083] Preferably, a hermetic door locks each of the cleaning chambers.

[0084] Preferably, the inlet and outlet nozzles and pipes of the fluid from the chamber Cleaning systems are equipped with fine mesh screens, known as filter screens, to retain fine fiber particles during the discharge of the fluid carrying unwanted substances. These screens prevent fine fibers from being carried along during the cleaning process and ending up with the extracted residue at the outlet.

[0085] Preferably, the installation includes a tank containing a fluid (in liquid state), said tank being connected to said cleaning chamber.

[0086] Such a fluid is preferably intended to be brought to the supercritical state.

[0087] Advantageously, the installation includes heating means and pressurizing means, controllable by a central unit, configured respectively to heat the fluid to a determined supercritical temperature and to compress the fluid to a determined supercritical pressure, said central unit determining the supercritical temperature and pressure as a function of the fluid.

[0088] The installation further includes expansion means configured to expand the fluid in order to continuously separate, throughout the cycle, the fluid from the solid and liquid contaminants transported, in order to recycle said fluid.

[0089] The relaxation means are preferably located in the installation upstream of said cleaning chamber; that is to say at the exit of the chamber.

[0090] The installation is sized proportionally to the chosen parameters and is capable of accommodating the defined parameters (pressure, temperature, flow rate, filtration, etc.). It includes components such as nozzles, pipes, conduits, tanks, separators, reservoirs, pumps, condensers, heating elements, sensors and pneumatic, hydraulic and mechanical controllers (flow meters, etc.).

[0091] Advantageously, the cleaning chamber includes a rotating drum into which the fibers are introduced. It is understood here that such a drum can be mounted on a rotating axis (magnetic or mechanical, for example) allowing the drum to rotate on its own axis.

[0092] The object of the present invention relates according to a fourth aspect to the use of fibers from cigarette butt filters for the manufacture of thermal and / or sound insulation, filters and / or biodegradable plastic objects.

[0093] It is therefore possible to manufacture eco-designed materials based on fibers from cigarette butts.

[0094] Preferably, the fibers are cellulose acetate fibers.

[0095] In a particular embodiment, the process as described above is implemented to decontaminate said fibers.

[0096] According to a first variant, the process is used to manufacture insulation (thermal or acoustic) panels, such use being particularly advantageous in the building and / or energy sector.

[0097] In one mode, these plates are made by mixing the decontaminated fiber from the filter with a two-component material or other compounds.

[0098] This use for the manufacture of insulation boards is appreciated in the field of HQE (High Environmental Quality) or THQE (Very High Environmental Quality) type buildings, but also in other fields such as automotive, agriculture, aeronautics, electronics, electrical, etc.

[0099] According to a second variant, the process is used to manufacture textile clothing articles, such articles being valued for their thermal and / or acoustic properties in particular.

[0100] In a particular embodiment, the insulating fibers and panels are sewn and / or inserted inside the garments, as padding to create ecological insulation.

[0101] According to a third variant, the fibres are conditioned to become filters again for filtration, mainly of liquid or gas.

[0102] According to a fourth variant, the fibers are used, in the processes and plastic transformation, pure or mixed to create new solid materials.

[0103] Thus, the present invention makes available to all actors involved in the recycling of cigarette butts an innovative technology using the properties of supercritical fluids to decontaminate fibers, and in particular cellulose acetate fibers.

[0104] Brief description of the attached figures

[0105] Other features and advantages of the present invention will become apparent from the description below, with reference to the accompanying figures which illustrate two non-limiting embodiments and on which:

[0106] [Fig.1]

[0107] Fig. 1 represents the phase diagram of carbon dioxide;

[0108] [Fig.2]

[0109] Figure 2 shows a schematic view of a cleaning installation implementing supercritical fluid technology for cleaning fibers from cigarette butt filters; and

[0110] [Fig.3]

[0111] Fig. 3 represents a flowchart of a process for cleaning fibres from cigarette butt filters. Detailed description

[0112] A method for cleaning cigarette butts according to an embodiment of the present invention and the installation associated with it will now be described in what follows with joint reference to figures 1 to 3.

[0113] As mentioned in the preamble, cleaning cigarette butts is a problem for which there is currently little effective technology, both for ecological / environmental and financial reasons.

[0114] One of the objectives of the present invention is to recover and decontaminate the fibers present in cigarette butts, and more specifically in cigarette filters, taking into consideration the ecological / environmental and financial constraints mentioned above.

[0115] Another objective of this document is to propose alternative solutions for the recycling and / or reuse of decontaminated fibres.

[0116] This is made possible in the example described below.

[0117] It is known that fibers from cigarette butts adsorb toxic substances and bad odors when burned.

[0118] These substances include organic and inorganic substances, notably: - nicotine, - heavy metals, - organic acids (acetic acid and / or tartaric acid), - nitrosamines, - flumetralines, pendimethalins and / or trifluralines - phenols, - polycyclic aromatic hydrocarbons (PAHs), - formaldehyde and acetaldehyde, - dioxins and / or furans, - anions (chlorides, nitrates, phosphates, sulfates and / or ammonium).

[0119] The cleaning and decontamination of these fibres consists of extracting these toxic substances adsorbed in these fibres during combustion in order to transform the cigarette butt, hazardous waste (classified: HP 14: ecotoxic and HP6: acute toxicity), into usable raw material.

[0120] The concept underlying the present invention is to exploit the technology of dense fluids under pressure, and in particular supercritical fluids, by removing these substances to efficiently clean the fibers of polluted filters.

[0121] The use of dense fluids under pressure, and in particular supercritical fluids, presents itself as an effective emerging technology which has very interesting transport properties.

[0122] The Applicant observes that supercritical fluid technology is classically used for the extraction of aromas (coffee or essential oils for example).

[0123] This technology is also used to dye textiles without water.

[0124] On the other hand, the use of such supercritical fluids has never been considered until now for the cleaning and decontamination of cigarette butts and in particular of cigarette butt fibers.

[0125] In the example described here, carbon dioxide is used as the fluid.

[0126] The Applicant submits that the use of carbon dioxide has the advantage of being an industrial waste product produced in large quantities. Reusing this waste is therefore very attractive: Carbon dioxide is available in high purity and at low cost.

[0127] A person skilled in the art will understand that other fluids such as those listed previously in the description may be reused within the scope of the present invention.

[0128] Fig. 1 therefore represents the phase diagram of carbon dioxide.

[0129] It is known that such a phase diagram exposes the different states of matter according to the different parameters associated with the pressure and temperature of the fluid.

[0130] Under normal temperature and pressure conditions, carbon dioxide can exist in gaseous, liquid, or solid states. However, it has a critical point Pc corresponding to a critical pressure and temperature, denoted Pc and Tc. When carbon dioxide is subjected to a pressure and temperature exceeding its critical point Pc, it enters a supercritical state.

[0131] Beyond the critical pressure Pc, any increase in temperature imposed on the liquid leads to the formation of a less dense liquid and different from the gaseous state.

[0132] Beyond the critical temperature Tc, any increase in pressure applied to the gas leads to the formation of a supercritical (more condensed) fluid without passing through the liquid state.

[0133] In the supercritical state, carbon dioxide then exhibits an intermediate behavior between the liquid and gaseous states, with particular properties: - the density is higher and therefore similar to that of liquids; - the diffusivity coefficient is between that of liquids and gases; - the viscosity is low, which is similar to that of gases.

[0134] These different states, formations and parameters are interesting and allow us to obtain a flexible solvent in order to target a wide range of substances to be extracted.

[0135] We speak of a supercritical fluid when a fluid is heated above its critical temperature Tcet and when it is compressed above its critical pressure Pc.

[0136] Adjusting these temperature and pressure parameters makes it possible to obtain a supercritical fluid with a solvent power comparable to that of liquid solvents, with interesting transport properties that bring them closer to gases.

[0137] It should be noted here that the Applicant has further observed that by combining a supercritical fluid such as carbon dioxide with fibers such as acetate The properties of cellulose acetate fiber were improved by contact with cellulose: this contact leads to a modification of the intrinsic properties of the polymer. It allows its viscosity to be lowered (glass transition).

[0138] The low viscosity and high diffusion coefficients of supercritical carbon dioxide enable effective cleaning due to the solvent's deep penetration into the core of the fiber. Combining these transport properties with efficient carbon dioxide extraction allows for complete cleaning.

[0139] According to the concept of the invention, carbon dioxide replaces the use of effective (but highly polluting) organic solvents such as hexane, dichloromethane, perchloroethylene, trichloroethylene and chloroform, or the use of aqueous solutions such as water.

[0140] It is thus understood that the supercritical state of carbon dioxide creates very efficient transport properties for the decontamination of fibers, and in particular of cellulose acetate fibers present in cigarette filters, without damaging them.

[0141] For carbon dioxide, the phase diagram of [Fig. 1] shows that the critical point Pc corresponds to a critical temperature Tc greater than or equal to 31 “Celsius and a critical pressure Pc greater than or equal to about 73.85 bars.

[0142] By varying these parameters correctly beyond these critical values ​​(31°Celsius and 73.85 bars), it is possible to bring the carbon dioxide to a supercritical state and obtain very effective cleaning.

[0143] Before proceeding with the actual cleaning, the process according to the present invention includes a collection step S0.

[0144] This collection step S0 can involve individuals as well as associations, communities, companies and all other collection actors.

[0145] This is a civic act for an environmental initiative. All the above-mentioned actors can be involved in such an initiative.

[0146] In the example described here, a series of cigarette butt processing operations is also planned during a PI phase, including a sorting step S 1_1 to separate cigarette butts from any other waste, a grinding step Sl_2, and a sieving step Sl_3 which may be repeated several times, in order to extract a maximum of tobacco, ash, and leaf.

[0147] Depending on the batch received, a friction step Sl_3, a sieving step Sl_4 and a cycloning step Sl_5 may also be added or not.

[0148] The succession of these different steps in the PI phase aims primarily to separate the cigarette fibres to be decontaminated from other waste such as, for example, cigarette leaves, ashes, tobacco.

[0149] It should be noted that, in the example described here, only the fibers of the filters containing in particular cellulose acetate are kept for the P2 depollution phase, the other waste being used in a phase for the production of compost.

[0150] Such compost is produced, for example, using another method.

[0151] In the embodiment described here, the different processing steps are carried out by the installation which includes a production line including in particular a treatment tank (not shown here) using a crusher, a sieve and / or cycloning and / or friction means (not shown here).

[0152] It is understood that installation 200 does not necessarily include this production line; this may be located on another site (processing carried out by subcontracting for example).

[0153] The installation 200 further includes a cleaning chamber 10 in the form of an autoclave, said chamber 10 being configured to clean the fibers from cigarette filters by bringing these fibers into contact with the fluid in a supercritical state.

[0154] The chamber 10 is therefore configured to contain a fluid in a supercritical state, and thus withstand high temperatures and pressures.

[0155] In the example described here, this chamber 10 is a hermetically sealed enclosure.

[0156] The first step S2_0 of this decontamination phase P2 therefore comprises the introduction and positioning of the fibers to be decontaminated in the cleaning chamber 10.

[0157] Here, the fibers are introduced into a fixed container.

[0158] However, several alternatives can be considered during cleaning to optimize and reduce the parameters used inside the cleaning chamber. Indeed, by combining supercritical technology with other mechanical, electrical, or chemical means, it is possible to reduce the elements required for cleaning. To optimize the process, that is, to reduce the time, the quantity of fluid, the pressure, and / or the temperature, the cleaning can be supplemented with one or more of these elements: - a rotating drum placed in the tank and driven by a magnetic or mechanical torque to set the material in motion in order to facilitate the diffusion of the supercritical fluid (in the form of a sieve or concrete mixer); and / or - a vibration and ultrasound system that allows for easier extraction of targeted substances, combining the advantages of ultrasound with those of supercritical carbon dioxide; and / or - means of mechanical compression, in particular by pneumatic or hydraulic jack, or screw conveyor, in order to compress the fiber and force the extraction of the molecules to be extracted; and / or - an internal mixer to homogenize the cleaning process; and / or - a centrifugal system to direct all extracted substances outwards, thus preventing them from being re-adsorbed elsewhere on the fiber; and / or an electrical current inside the tank to electrocute the fiber and facilitate extraction; and / or - soaking in an aqueous solution during the cleaning cycle (supercritical fluid-liquid configuration).

[0159] All these improvements can be used individually or in combination. Agitation, vibration, compression, tension, or any other movement and action can be added to advantageously improve or optimize cleaning conditions on any quantity of material.

[0160] These applications are obviously optional and in no way restrictive.

[0161] The concept underlying the present invention is to bring these fibers into contact in chamber 10 with a fluid in a supercritical state, here carbon dioxide.

[0162] In this example, the cleaning chamber 10 is therefore to be connected to a reservoir 20 containing carbon dioxide.

[0163] For this purpose, a set of valves, nozzles and inlet and outlet pipes (not shown here) are provided, configured to connect the cleaning chamber 10 and the reservoir 20.

[0164] Preferably, these elements are provided with fine grids to retain and filter fine fiber particles that may be carried along during the evacuation of the fluid carrying the undesirable substances.

[0165] Such grids prevent these fine fibers from being transported out of the chamber during cleaning and ending up with the unwanted residues extracted at the outlet.

[0166] Prior to bringing the fluid into contact with the fibers to be decontaminated, it is desirable to bring said fluid to a supercritical state.

[0167] In this example, it is then envisaged that the cleaning chamber 10 comprises compression means 30 and heating means 40 configured respectively to compress said fluid in a step S2_l to a supercritical target pressure Psc and to heat said fluid in a step S2_2 to a supercritical target temperature Tsc.

[0168] In this example, the compression means 30 and heating means 40 are controllable by a central unit 50.

[0169] This central unit 50 thus includes electronic storage means (not shown here) storing information relating to the parameters associated with supercritical cleaning such as supercritical temperature and pressure Tsc and Psc depending on the fluid used.

[0170] In this example, these supercritical temperatures and pressures Tsc and Psc correspond respectively to a temperature greater than or equal to 31° Celsius and a pressure greater than or equal to 73.85 bar. These parameters are associated here with carbon dioxide as stated previously.

[0171] It should be noted here that the energy resources to achieve these parameters are very low and not very energy-intensive.

[0172] In the example described here, it is the central unit 50 which controls the compression means 30 and heating means 40 to bring the fluid to the supercritical state.

[0173] In this example, an additional step S2_3 of fiber humidification can be provided. Such humidification S2_3 acts as a co-solvent for the fibers and makes it easier to solubilize the nicotine during the cleaning operation.

[0174] This step S2_3 remains optional.

[0175] Once the fluid has been brought to the supercritical state, the depollution phase P2 includes bringing the supercritical fluid into contact S2_4 with the fibers to be depolluted (possibly moistened) inside the autoclave lO. As explained previously, carbon dioxide in the supercritical state proves to be a powerful solvent: bringing such a supercritical fluid into contact S2_4 with the fibers of cigarette butts to be depolluted makes it possible to extract from the fibers nonpolar organic molecules, such molecules being mainly formed of long carbon chains of low molar mass (lipids and fats).

[0176] The S2_4 contact can be made in several forms, potentially combined with each other: high pressure vaporization, soaking, jet nozzle, spraying, etc.

[0177] In the example described here, soaking is combined with the action of a jet.

[0178] The cleaning chamber 10, or autoclave, thus includes spraying means (not shown here) capable of emitting a jet of carbon dioxide in a supercritical state.

[0179] In this example, the electronic storage means store other parameters relating to cleaning such as, for example, the contact time (soaking time), the jet flow rate and / or the jet speed.

[0180] In this example, the jet propelled towards the fibers is expected to have a variable speed between 1 and 500 meters per second with a flow rate between 1 and 4000 liters per hour.

[0181] In this example, it is anticipated that the S2_4 contact will be carried out for a period of between one minute and eight hours, this period varying according to the desired cleanliness characteristics and the quantity of material to be treated.

[0182] In this example, the electronic storage means store further parameters associated with the contact.

[0183] Pressure and temperature variations can be predicted according to compression and vacuum cycles; such cycles improve pollution control performance.

[0184] Parameters relating to the rotational speed of the rotating drum can also be specified.

[0185] This can also be animated by jerks or by movements other than rotational (pendular or other).

[0186] In order to improve the performance associated with the P2 pollution control, it is possible to add a co-solvent to the fluid during a step S2_5.

[0187] The addition S2_5 of a co-solvent (methanol, ethanol, etc.) during the depollution phase increases the polarity and selectivity of the cleaning in order to also extract polar organic molecules with shorter chains (sugar, ions...).

[0188] In the example described here, this addition S2_5 is planned between the compression step S2_1 and the heating step S2_2. This co-solvent can also be added upstream or downstream of the cleaning process. The choice and use of these co-solvents depends on the target substances to be extracted in order to meet the standards of the various market outlets.

[0189] It should be noted that the development of chambers operating at high pressure (above 350 bars) makes it possible to extract increasingly polar molecules without the addition of co-solvents.

[0190] To extract inorganic materials such as heavy metals for example, the installation 200 is further configured to add, during a step S2_6, extracting molecules of the calixarene type, or solutions of agents capable of extracting inorganic substances (complexants, chelators, antioxidants...) to the supercritical fluid.

[0191] This additional S2_6 allows the formation of complexes with inorganic compounds, which will allow them to be transported at the same time.

[0192] In the example described here, as with step S2_5, this addition S2_6 is carried out between the compression step S2_1 and the heating step S2_2. This extractant can also be added upstream or downstream of the cleaning process. The choice and use of these extractants depends on the substances targeted for extraction in order to meet the standards of the various market outlets.

[0193] The addition of co-solvents and / or extractants is implemented by the central unit 50 which controls means 60 capable of injecting co-solvents and / or extractants into said fluid.

[0194] Upon exiting the chamber, the fluid is cooled and depressurized by expansion means 70 during a step S3 to transition to a gaseous state (or expansion). These expansion means 70 allow the fluid to expand in order to continuously separate the fluid from the transported solid and liquid contaminants.

[0195] The carbon dioxide is then released in gaseous form by means of a recovery system 80 which acts as a separator between the fluid and the contaminants. These steps are carried out continuously during the cleaning cycle; this separator 80 discharges the carbon dioxide in gaseous form during step S4 to a condenser 90 which transforms the carbon dioxide into a liquid state during step S5 before returning it to the storage tank 20 for reuse.

[0196] This separator 80 removes contaminants into a separate and isolated container.

[0197] At the end of the cycle, several particle / molecular filtration or absorption steps may optionally be added (in addition to the continuous separation carried out during the transition from the supercritical to the gaseous state during cleaning) as additional steps on the fluid in the liquid, gaseous, or supercritical state, during or after the cycle in order to ensure complete separation of undesirable liquid and / or solid particles that may have remained solubilized in the fluid, in order to recover pure supercritical fluid to be reinjected on the following cycles.

[0198] This fluid may pass through activated carbon to capture any odor molecules and VOCs. Activated carbon may be added to the cleaning chamber if necessary.

[0199] It should be noted that this fluid can return to the cleaning chamber 10 as many times as necessary. The remainder of the polluted stream is then discharged and treated, because as it is released and changes to a gaseous state, the carbon dioxide separates from the contaminants.

[0200] These contaminants are used during a recovery phase of organic and inorganic substances (hydrocarbons, heavy metals, pesticides, sugars, etc.). Such recovery is carried out, for example, using another treatment process.

[0201] The decontaminated fiber is then recovered.

[0202] Thus, supercritical fluid fiber cleaning technology allows the fluid to continuously recycle itself automatically by changing state. Upon exiting the chamber, during expansion (loss of density), it transitions from a supercritical to a gaseous state and loses its effectiveness as a powerful solvent, releasing the undesirable substances (in liquid or solid form) transported during the supercritical state. These undesirable substances are collected in specialized containers for processing and reuse.

[0203] Once the physicochemical separation is complete, the fluid can be reinjected into the chamber in a supercritical state. A filtration / absorption separation step can be added to facilitate the recovery of residues solubilized in the fluid (during or after cleaning, in gaseous, liquid, or supercritical state), and to purify the fluid in order to recover its full extraction efficiency.

[0204] The fluid passes through one or more enclosures and separators (accompanied by pressure relief valves) capable of purifying it and making it reusable, by capturing and collecting all contaminants.

[0205] In the example described here, the fluid also passes through an activated carbon filter to trap odor molecules and volatile organic compounds. Activated carbon can also be added to the chamber. This step is not mandatory.

[0206] The high volatility of the fluid under atmospheric conditions categorizes the fluid as a dry solvent, thus requiring no drying step.

[0207] The inert, non-toxic, and non-hazardous solvent fluid does not pose a risk of damaging the working conditions of users.

[0208] The present invention makes it possible to obtain a technology which does not have the disadvantages of the prior art.

[0209] By adapting supercritical fluid technology and adjusting parameters relating in particular to pressure, temperature, flow rate, contact time, co-solvents and extradants, the present invention makes it possible to decontaminate fibers from cigarette butt filters by extracting odors, organic and inorganic matter which classifies the cigarette butt as undesirable waste.

[0210] This extraction is achieved by separating these toxic substances and odors from the fibrous material. Such a technology then provides an environmentally friendly cleaning method involving very little water and / or chemical solvents.

[0211] Such technology makes it possible to manage very large quantities easily, with little effluent to treat.

[0212] Such cleaning then makes it possible to revalue the cigarette butt which has become a real toxic waste for the environment.

[0213] The valorization of these cigarette butts is one of the other advantageous aspects which directly results from the present invention.

[0214] Indeed, by decontaminating the fibers it becomes possible to reuse them and to exploit the technical characteristics of these fibers and in particular of these cellulose acetate fibers, such fibers having interesting acoustic and / or thermal properties.

[0215] It is therefore possible to use the decontaminated fibres for the field of insulation, in bulk form or in such a way that these fibres can for example be arranged and transformed into plates in order to create insulation rolls.

[0216] To achieve this, it is preferable to bond and solidify the recycled cellulose acetate fibers together. A two-component material is then added and mixed with the fiber. This two-component material, of the Trevira 255 2.2 dtex / 6 mm type: PES copolyethylene, is a material composed of a core and its outer layer. Its outer layer Being more sensitive to heat, it melts at temperatures lower than that of the core and other components, thus unifying all the fibers. These two-component materials were therefore chosen based on the characteristics of the recycled fibers. This process also works with any type of two-component material (including bio-based materials).

[0217] It is desirable to carry out a homogeneous mixing and blending of the cellulose acetate fibers and the initial two-component material (for example 15% two-component material and 85% acetate fiber) in order to obtain a good distribution of materials for good solidification and harmonization of the plate.

[0218] The distribution of two-component material and acetate fibers can vary according to the desired characteristics of the material (more or less solid, flexible, resistant, etc.).

[0219] It will be understood that the addition of two-component material makes the material stronger and more rigid. These sheets can also be shaped by other processes such as bonding, weaving, carding, spinning, compression, etc. The resulting insulating material can then be used for insulation in the building sector, but also in the clothing sector and in any other field requiring an insulating fiber.

[0220] This decontaminated fibre can also be used to form filters and / or filtration systems for air, water, liquid or gas (urban, automotive, aeronautical, hydrocarbon, etc. sectors).

[0221] Cellulose acetate can still be reduced to a material usable in all types of plastics processes (including molding) so that this recycled material can be transformed into objects. It can be mixed with other materials to create biodegradable products. Furthermore, it can also be used in the field of composites by mixing it with other materials. It is also used in all types of materials.

[0222] For this application, the fiber is to be reduced to powder or made usable in plastics processing. This allows it to be inserted into machines such as extrusion, injection, molding, thermocompression, or thermoforming machines. It should be noted that such a material is processed at temperatures between 80°C and 300°C in these various processes.

[0223] Thus, it will be understood that the present invention provides for the implementation of a supercritical fluid technology for cleaning and decontaminating fibers from cigarette butt filters. Such cleaning and decontamination are achieved by bringing said fibers into contact with a fluid such as carbon dioxide in a supercritical state.

[0224] By adjusting the parameters of the autoclave into which the cigarette butt fibers are introduced, it is possible to bring the fluid to a target temperature and pressure, known as supercritical, allowing for efficient extraction of the toxic substances contained in the fibers. The process implemented is also environmentally friendly and has an acceptable industrial cost.

[0225] Once decontaminated without the need for further decontamination, these fibers can be reused as a new eco-designed material, used in bulk and / or processed in several areas, such as: - textile clothing items (insulating coat padding, insulating quilting, sewing threads, fabrics, wool for use in the creation of clothes or textile-based objects: mattresses, cushions, duvets, hats, head coverings, handbags...); - thermal and / or acoustic insulation materials (building, electronics, automotive: lithium battery insulation for electric vehicles, aeronautics, shipbuilding and all other fields requiring thermal and / or acoustic insulation...); - filtering materials (liquid, gas...); in the form of fibrous sheets or loose fibers conforming to the standards of the field of use.

[0226] These fibres are also valued in the field of plastics processing in order to create new eco-designed solid materials with or without blending.

[0227] It will be understood that these new materials will be of the type raw material, semi-finished or finished products.

[0228] Other uses are also envisaged within the scope of the present invention.

[0229] This supercritical fluid cleaning technology has very interesting extraction and cleaning properties, even more effective than the polluting solvents, detergents, and aqueous solutions used until now. This supercritical fluid cleaning has the advantage of being completely green, neutral, and environmentally friendly, with low discharge quantities (virtually no residual effluent after cleaning, requiring little secondary treatment and therefore economically advantageous), which allows for the easy handling of large quantities.

[0230] It should be noted that this detailed description relates to several specific embodiments of the present invention, but that in no way does this description limit the scope of the invention; on the contrary, its purpose is to eliminate any possible ambiguity or misinterpretation of the following claims

Claims

Demands

1. Use of decontaminated cellulose acetate fibers from smoked cigarette butt filters for the manufacture of: - thermal and / or acoustic insulation, and / or - filters; and / or - biodegradable plastic objects, characterized in that said fibers have been previously decontaminated by a cleaning process comprising the following steps: - a treatment (S1_1, S1_2, S1_3, S1_4, S1_5) of said cigarette butts to extract said fibers to be decontaminated; and - a decontamination (S2_0, S2_1, S2_2, S2_3, S2_4, S2_5, S2_6) of said fibers by contacting (S2_4) them with a dense fluid under pressure in a supercritical state, called a supercritical fluid

2. Use according to claim 2 for manufacturing thermal and / or acoustic insulation plates and / or rolls, wherein said plates and / or rolls are made by mixing fibers from filters with a two-component material.

3. Use according to claim 2, wherein the two-component material is of the type Trevira 255 2.2 dtex / 6 mm: PES copolyethylene.

4. Use according to claim 2 or 3, wherein the mixture is made by homogeneous mixing of said fibers, preferably cellulose acetate fibers, and the two-component material.

5. Use according to claim 4, wherein the blend comprises 15% of two-component material and 85% of acetate fiber.

6. Use according to claim 2 for manufacturing thermal and / or acoustic insulation plates and / or rolls for building and / or energy.

7. Use according to claim 2 for manufacturing thermal insulation plates and / or rolls for making textile articles.

8. Use according to claim 7, wherein the insulating panels are sewn and / or inserted inside clothing to achieve padding.

9. Use according to claim 2 for making filters for air, gas, liquids 22

10. Use according to claim 2 for making plastic materials, in particular biodegradable ones.

11. Use according to claim 10, wherein the fiber is reduced to powder in order to be able to insert it into machines such as extrusion, injection, molding, thermocompression or thermoforming machines.

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