Pyrolysis of aerosol-generating article waste

Abstract

A method of processing waste consumable aerosol-generating articles by pyrolysis, the method comprising the steps of: feeding waste consumable aerosol-generating articles into a pyrolysis reactor, the aerosol-generating articles comprising at least some aerosol-generating articles comprising an aerosol-generating substrate with a metallic susceptor; heating the aerosol-generating articles in the pyrolysis reactor to a temperature sufficient to cause pyrolysis of non-metallic components of the aerosol-generating articles into gaseous products and char, wherein the temperature is less than a melting temperature of the metallic susceptors; extracting the gaseous products from the pyrolysis reactor and feeding the gaseous products to a condensing separator; and feeding the char from the pyrolysis reactor to a magnetic separator and separating the metallic susceptors from the char by applying a magnetic field; wherein at least some of the heat in the pyrolysis reactor is generated by applying an alternating electromagnetic field to the aerosol-generating articles so as to induce eddy currents in the metallic susceptors.

Description

[0001] PYROLYSIS OF AEROSOL-GENERATING ARTICLE WASTE

[0002] The present disclosure relates to a method and apparatus for pyrolysis of waste products associated with aerosol-generating articles.

[0003] In the manufacture of aerosol-generating articles, for example heat-not-burn heated tobacco products, heat-not-burn nicotine-containing products, and hybrids thereof, various elements are combined to make the aerosol-generating articles. Typically, these articles comprise an aerosol-generating substrate, for example tobacco cast leaf, cut tobacco filler, other agricultural products, such as clove, menthol and guar gum, glycerine, one or more filter elements, for example comprising a cellulosic material, for example cellulose acetate, an aerosol-cooling element, for example comprising a polylactic acid material or an acetate material, and a metallic susceptor element that, when heated, causes the aerosol-generating substrate to heat up and release an aerosol. The various elements are arranged in a desired configuration and assembled as rod-shaped articles wrapped in an outer wrapper, which may be made of paper or other material.

[0004] Such aerosol-generating articles are often called “consumables”, since they are used in combination with an aerosol-generating device into which the aerosol-generating articles are inserted for consumption. The aerosol-generating device generally comprises a power source and control electronics for heating the aerosol-generating article in a controlled manner so as to generate an aerosol which is inhaled by a user. The aerosol-generating device is designed for repeated use, but the aerosol-generating articles, after the aerosol-generating substrate has been depleted, are intended for disposal. It would be desirable to provide an efficient and environmentally-friendly method for processing waste aerosol-generating articles.

[0005] Some consumables are made of an assembly of different plugs, including a Mouth Piece Filter (MPF) which is a filtering plug usually containing plasticized cellulose acetate, or paper or viscose fibres, and a Sensorial Media (SM) plug containing a Sensorial Media substrate (for instance, Tobacco Cast Leaf (TCL), which is a sheet-shaped tobacco compound crimped and gathered into a rod shape, or a paper-like substrate loaded with nicotine, or cut tobacco filler, or other suitable SM substrate). The SM substrate generates an aerosol when heated.

[0006] Such consumables can be heated to generate an aerosol by external heating or by internal heating. In the case of external heating, the heat comes from outside the consumable. For example, the heat can be applied by portions of the walls of a cavity of a heating device into which the consumable is inserted, and which are heated by resistance heating. In the case of internal heating, the heat comes from inside the consumable. The heat can be applied by a resistance heated blade connected to a heating device and inserted into the consumable, or by a metallic strip or element, called a susceptor, that is disposed in the SM plug of the consumable and heated by induction heating. Consumables with a susceptor are inserted into aerosol-generating device, such as an electronic smoking device, which creates, when activated, an alternating magnetic field generating eddy currents in the susceptor. The eddy currents heat the susceptor by way of the Joule effect (resistance heating), and the susceptor then heats the SM substrate.

[0007] Susceptors are usually planar metal strips, and are made of a material that is both electrically conductive and resistive, for example ferritic magnetic stainless steel AISI 430.

[0008] In the case of consumables having a right circular cylindrical shape, the susceptor is usually positioned in the centre of the SM plug, so that the longitudinal axis of the susceptor is aligned with the longitudinal axis of the SM plug. The length of the susceptor may be substantially the same as the length of the SM plug. The width of the susceptor may be less than the width or diameter of the SM plug.

[0009] Figures 1 and 2 show an aerosol-generating article 1 in the form of an SM plug comprising an aerosol-generating substrate 2 and an embedded metallic susceptor 3 in the form of a planar metal strip. The aerosol-generating substrate 2 and metallic susceptor 3 are surrounded by a wrapper 4 to form a substantially cylindrical component. Exemplary SM plugs have a diameter of 7 millimetres to 9 millimetres, and a length of 8 millimetres to 16 millimetres, although these dimensions are not intended to be limiting.

[0010] It will be appreciated that, due to the various different materials from which consumable aerosol-generating articles are made, responsible waste management presents a challenge.

[0011] There is a waste management hierarchy defining, from most preferable to least preferable, the various options for managing waste: i) prevent (i.e. not generating waste at all); ii) reduce (i.e. reducing the amount of waste generated); iii) reuse (i.e. giving a product a second life before wasting, for example cleaning and refilling a used glass bottle); iv) recycle (i.e. reprocessing the waste product); v) recover (i.e. incinerate and recover the heat energy) and vi) dispose (e.g. in landfill).

[0012] Pyrolysis refers to the thermal decomposition of materials through heating at high temperatures. For organic materials, heating is usually to between 300 degrees Celsius and 800 degrees Celsius. Biomass materials such as wood (including paper) and leaves (such as tobacco) typically do not melt but decompose directly into char, gases, and liquid byproducts.

[0013] Although pyrolysis is towards the bottom of the waste management hierarchy indicated above, valuable residues may be created or recovered when applied to waste consumable aerosol-generating articles. For example, pyrolysis of used cigarette filter waste including cellulose acetate filters plasticized with glycerol triacetate has been employed to generate char, together with oils and gases. Moreover, pyrolysis has been applied to waste consumable aerosolgenerating articles that do not include metallic susceptors.

[0014] However, the presence of metallic susceptors in some kinds of consumable aerosolgenerating article waste presents a number of difficulties for pyrolysis processes. According to a first aspect of the present invention, there is provided a method of processing waste consumable aerosol-generating articles by pyrolysis, the method comprising the steps of: feeding waste consumable aerosol-generating articles into a pyrolysis reactor, the aerosolgenerating articles comprising at least some aerosol-generating articles comprising an aerosolgenerating substrate with a metallic susceptor; heating the aerosol-generating articles in the pyrolysis reactor to a temperature sufficient to cause pyrolysis of non-metallic components of the aerosol-generating articles into gaseous products and char, wherein the temperature is less than a melting temperature of the metallic susceptors; extracting the gaseous products from the pyrolysis reactor and feeding the gaseous products to a condensing separator; and feeding the char from the pyrolysis reactor to a magnetic separator and separating the metallic susceptors from the char by applying a magnetic field.

[0015] The waste consumable aerosol-generating articles may be used consumable aerosolgenerating articles. Such used consumable aerosol-generating articles may be collected from users as part of a recycling programme. The waste consumable aerosol-generating articles may also be rejected consumable aerosol-generating articles from a production line, the rejected consumable aerosol-generating articles not meeting quality standards. A mixture of both used and rejected consumable aerosol-generated articles may be processed together.

[0016] The waste aerosol-generating articles may, in some embodiments, be mixed with other biomass, for example wood or paper, in order to enhance the pyrolysis process. The mixing may take place prior to or during feeding into the pyrolysis reactor. In some embodiments, the other biomass may comprise wood chips or wood pellets. The wood chips or wood pellets may be or be derived from waste wood, for example woody horticultural waste or landscape maintenance wood.

[0017] Alternatively or in addition, the waste aerosol-generating articles may, in some embodiments, be mixed with other waste, such as one or more of conventional cigarette waste, cigarette filters, aerosol-generating article filters, aerosol-generating substrate waste, organic waste and other waste associated with the manufacture of or consumption of aerosol-generating articles or conventional cigarettes.

[0018] The waste consumable aerosol-generating articles may be mixed with other biomass or other waste in a mass ratio from 10:1 to 1 :10 (i.e. from 10 parts by mass of waste consumable aerosol-generating articles mixed with one part by mass of other biomass or other waste, to one part by mass of waste consumable aerosol-generating articles mixed with 10 parts by mass of other biomass or other waste). Preferably, the waste consumable aerosol-generating articles may be mixed with other biomass or other waste in a mass ratio from 1 :1 to 1 :10, more preferably a mass ratio of about 1 :5. At least some of the heat in the pyrolysis reactor may be generated by applying an alternating electromagnetic field to the aerosol-generating articles so as to induce eddy currents in the metallic susceptors. The eddy currents may heat the metallic susceptors by way of the Joule effect. This has the advantage of heating the aerosol-generating substrate portions of the aerosol-generating articles from inside, helping to generate a more even and rapid distribution of heat within a bulk load of waste consumable aerosol-generating articles in the pyrolysis reactor. Rapid heating may encourage a fast pyrolysis process in which valuable hydrocarbons are vaporised and can subsequently be fractionally distilled as bio-oil and syngas in the condensing separator.

[0019] The alternating electromagnetic field may be applied by way of at least one induction coil. The at least one induction coil may be configured to generate an alternative magnetic field that is substantially aligned with or substantially perpendicular to an alignment of the metallic susceptors in the pyrolysis reactor. The at least one induction coil may be disposed close to a pathway of the waste consumable aerosol-generating articles through the pyrolysis reactor for greater efficiency of eddy current induction in the metallic susceptors.

[0020] At least some of the heat in the pyrolysis reactor may be generated by at least one electrical heater. At least some of the heat in the pyrolysis reactor may be generated by at least one gas heater.

[0021] The aerosol-generating articles in the pyrolysis reactor may be heated by a combination of inductive heating of the susceptors due to an alternating electromagnetic field, and direct heating by of an electrical heater, or a gas heater, or both an electrical and a gas heater.

[0022] At least some of the heat in the pyrolysis reactor may be generated by applying an alternating electromagnetic field to the aerosol-generating articles so as to induce eddy currents in the metallic susceptors.

[0023] The aerosol-generating articles in the pyrolysis reactor may be heated to a temperature of up to 700 degrees Celsius. The aerosol-generating articles in the pyrolysis reactor may be heated to a temperature of up to 600 degrees Celsius. The aerosol-generating articles in the pyrolysis reactor may be heated to a temperature above 400 degrees Celsius. The aerosolgenerating articles in the pyrolysis reactor may be heated to a temperature above 500 degrees Celsius. The aerosol-generating articles in the pyrolysis reactor may be heated to a temperature between 500 degree Celsius and 600 degrees Celsius. The aerosol-generating articles in the pyrolysis reactor may be heated to a temperature of about 550 degrees Celsius.

[0024] The heating temperature in the pyrolysis reactor may be chosen to promote fast pyrolysis of non-metallic components of the aerosol-generating articles while avoiding unwanted melting or vaporization of any metallic susceptors that may be present. Unwanted melting or vaporization of the metallic susceptors may cause contamination of solid, gas or oil products of pyrolysis. Some metallic elements, when heated, could react with other elements or compounds in biomass products of pyrolysis, forming undesirable compounds. In addition, melting or vaporization of the metallic susceptors could result in subsequent deposition or resolidification of metal in other parts of the pyrolysis reactor, which might require cleaning or reduce the efficiency of the pyrolysis reactor.

[0025] The use of induced eddy currents in the metallic susceptors, optionally combined with electric or gas heating, may avoid problems associated with microwave pyrolysis. This is because microwave pyrolysis of aerosol-generating articles containing metallic susceptors could give rise to microwave arcing and uneven heating or overheating. Moreover, the metallic susceptors could shield other parts of the aerosol-generating articles from the microwaves. In extreme cases, microwave pyrolysis could cause unwanted ignition, which could present a fire risk and give rise to unwanted chemical reactions.

[0026] A substantially inert gas may be supplied to the pyrolysis reactor during pyrolysis of the aerosol-generating articles. The inert gas may, for example, be nitrogen or carbon dioxide. The provision of an inert gas may help to suppress or prevent unwanted ignition or combustion of the aerosol-generating articles in the pyrolysis reactor. The inert gas may be supplied through at least one nozzle into the pyrolysis reactor so as to cause the aerosol-generating articles to become fluidized, or form a fluidized bed. By “fluidized” is meant that the aerosol-generating articles become suspended or entrained in an inert gas flow so that a mass of the aerosolgenerating articles behaves like a fluid, which can improve heat transfer and pyrolysis efficiency. The at least one nozzle may be directed upwardly from a base of the pyrolysis reactor.

[0027] The condensing separator may separate at least one of bio-oil and syngas from the gaseous products extracted from the pyrolysis reactor. Bio-oil, or syngas, or both bio-oil and syngas, may be recovered from the pyrolysis reactor and used for other purposes.

[0028] Syngas may be used for energy generation.

[0029] The condensing separator may be a fractional distillation separator. This may allow different organic fractions to be extracted from the gaseous products from the pyrolysis reactor.

[0030] Preferably, the waste consumable aerosol generating articles are not comminuted prior to feeding into the pyrolysis reactor. This is in contrast to existing processes for pyrolysis of cigarette butt waste not comprising metallic susceptors, where the cigarette butts are comminuted or ground prior to pyrolysis. Although comminution of a pyrolysis feedstock might appear to be advantageous in terms of increasing a surface area of the feedstock for exposure to heat, such comminution is problematic when metallic susceptors are present. This is because the metallic susceptors will themselves be comminuted, and this may give rise to contamination of the pyrolysis products and make it difficult to separate the metallic susceptors from the biomass products of pyrolysis. In addition, comminuting the metallic susceptors may increase the likelihood of unwanted melting, vaporization or chemical reaction of the metallic elements of the metallic susceptors in the pyrolysis reactor. Prior to feeding the waste consumable aerosol-generating articles into the pyrolysis reactor, aerosol-generating articles comprising a metallic susceptor may be separated from aerosolgenerating articles not comprising a metallic susceptor by way of a magnetic separator. This may allow aerosol-generating articles comprising a metallic susceptor to undergo different process steps to aerosol-generating articles not comprising a metallic susceptor.

[0031] For example, the separated aerosol-generating articles not comprising a metallic susceptor may be comminuted to form a comminated feedstock. The separated aerosol-generating articles not comprising a metallic susceptor may be comminuted in a grinder. This may allow the surface area of feedstock comprising the aerosol-generating articles not comprising a metallic susceptor to be increased and help to improve an efficiency of pyrolysis.

[0032] In one embodiment, the comminuted feedstock may be fed into the pyrolysis reactor together with the aerosol-generating articles comprising a metallic susceptor. The pyrolysis reactor may employ induction heating as described above, optionally together with an electric or gas heater.

[0033] In another embodiment, the comminuted feedstock may be fed into a separate pyrolysis reactor and processed separately from the aerosol-generating articles comprising a metallic susceptor. The separate pyrolysis reactor may employ direct heating such as an electric heater or a gas heater. The separate pyrolysis reactor may employ microwave heating, in which microwave energy is used to generate heat within the comminuted feedstock by vibration of water molecules. The separate pyrolysis reactor may employ plasma heating, in which a plasma (ionized gas) torch is used to generate a very high temperature to decompose the comminuted feedstock into syngas and solid residue.

[0034] Prior to feeding the waste consumable aerosol-generating articles into the pyrolysis reactor, a magnetic field may be applied so as to cause the aerosol-generating articles comprising a metallic susceptor to align in a predetermined orientation. The predetermined orientation may be selected for more efficient inductive coupling with the at least one induction coil of the pyrolysis reactor, thus improving induction heating efficiency.

[0035] A stream of waste consumable aerosol-generating articles may be passed through the pyrolysis reactor on a conveyor. This allows the method to be configured as a continuous process. The conveyor may be a belt conveyor. The conveyor may be an auger conveyor.

[0036] The conveyor may carry the stream of aerosol-generating articles along a pathway. The pathway may be a pathway through the pyrolysis reactor.

[0037] At least one electromagnetic induction coil may be disposed adjacent to the pathway to induce eddy currents in the metallic susceptors in the stream of aerosol-generating articles. A plurality of flat electromagnetic induction coils may be provided along the pathway, each coil having a normal axis directed towards the pathway. This may enable efficient induction heating of the metallic susceptors. At least one heater may be disposed adjacent to the pathway to heat the stream of aerosolgenerating articles. The at least one heater may be an electric heater or a gas heater.

[0038] A temperature in the pyrolysis reactor may be measured with a temperature sensor. A speed of the conveyor may be controlled as a function of the measured temperature. A current in the at least one electromagnetic induction coil may be controlled as a function of the measured temperature. The heater, where provided, may be controlled as a function of the measured temperature. This may allow the pyrolysis process to be controlled for improved efficiency. Feedback information from the temperature sensor can be used to maintain a desired pyrolysis temperature in the pyrolysis reactor by enabling one or more of the speed of the conveyor, the current in the at least one electromagnetic induction coil and the heat generated by the heater to be adjusted automatically or manually as required.

[0039] The method of the first aspect of the present invention may help to extract useful components from waste aerosol-generating articles, including those that comprise metallic susceptors, for re-use or recycling. Components may include syngas and bio-oil. The metallic susceptors may be separated from remaining char after pyrolysis and recycled.

[0040] According to a second aspect of the present invention, there is provided an apparatus for processing waste consumable aerosol-generating articles by pyrolysis, the apparatus comprising: a pyrolysis reactor configured to receive waste consumable aerosol-generating articles, the aerosol-generating articles comprising at least some aerosol-generating articles comprising an aerosol-generating substrate with a metallic susceptor; at least one heater configured to heat the aerosol-generating articles in the pyrolysis reactor to a temperature sufficient to cause pyrolysis of non-metallic components of the aerosolgenerating articles into gaseous products and char, wherein the temperature is less than a melting temperature of the metallic susceptors; a condensing separator configured to receive gaseous products from the pyrolysis reactor; and a magnetic separator configured to receive the char from the pyrolysis reactor and to separate the metallic susceptors from the char by applying a magnetic field.

[0041] The at least one heater may comprise at least one electromagnetic induction coil configured to apply an alternating electromagnetic field to the aerosol-generating articles so as to induce eddy currents in the metallic susceptors.

[0042] The at least one heater may comprise an electrical heater. The at least one heater may comprise a gas heater.

[0043] The aerosol-generating articles in the pyrolysis reactor may be heated to a temperature of up to 700 degrees Celsius. The aerosol-generating articles in the pyrolysis reactor may be heated to a temperature of up to 600 degrees Celsius. The aerosol-generating articles in the pyrolysis reactor may be heated to a temperature above 400 degrees Celsius. The aerosol- generating articles in the pyrolysis reactor may be heated to a temperature above 500 degrees Celsius. The aerosol-generating articles in the pyrolysis reactor may be heated to a temperature between 500 degree Celsius and 600 degrees Celsius. The aerosol-generating articles in the pyrolysis reactor may be heated to a temperature of about 550 degrees Celsius.

[0044] The apparatus may further comprising a source of a substantially inert gas configured to supply the substantially inert gas to the pyrolysis reactor during pyrolysis of the aerosol-generating articles. The pyrolysis reactor may comprise at least one nozzle through which the substantially inert gas is supplied so as to cause the aerosol-generating articles in the pyrolysis reactor to form a fluidized bed.

[0045] The condensing separator may be configured to separate at least one of bio-oil and syngas from the gaseous products extracted from the pyrolysis reactor. The condensing separator may be a fractional distillation separator.

[0046] The apparatus may further comprise a magnetic separator configured to separate aerosolgenerating articles comprising a metallic susceptor from aerosol-generating articles not comprising a metallic susceptor prior to feeding the waste consumable aerosol-generating articles into the pyrolysis reactor.

[0047] The apparatus may further comprise a comminutor configured to comminute the separated aerosol-generating articles not comprising a metallic susceptor to form a comminuted feedstock. The comminutor may be a grinder.

[0048] The pyrolysis reactor may be configured to receive the comminuted feedstock together with the aerosol-generating articles comprising a metallic susceptor.

[0049] The apparatus may comprise a further pyrolysis reactor configured to receive the comminuted feedstock for processing separately from the aerosol-generating articles comprising a metallic susceptor.

[0050] The apparatus may comprise a magnetic field generator configured to apply a magnetic field to cause the aerosol-generating articles comprising a metallic susceptor to align in a predetermined orientation prior to feeding the waste consumable aerosol-generating articles into the pyrolysis reactor.

[0051] The apparatus may comprise a conveyor configured to convey a stream of waste consumable aerosol-generating articles through the pyrolysis reactor. The conveyor may be a belt conveyor. The conveyor may be an auger conveyor. The conveyor may be configured to carry the stream of aerosol-generating articles along a pathway. The pathway may be a pathway through the pyrolysis reactor.

[0052] At least one electromagnetic induction coil may be disposed adjacent to the pathway to induce eddy currents in the metallic susceptors in the stream of aerosol-generating articles. The apparatus may comprise a plurality of flat electromagnetic induction coils disposed adjacent to the pathway, each coil having a normal axis directed towards the pathway. The apparatus may comprise at least one heater disposed adjacent to the pathway to heat the stream of aerosol-generating articles.

[0053] The apparatus may comprise a temperature sensor to measure a temperature in the pyrolysis reactor. The apparatus may comprise control circuitry to control a speed of the conveyor as a function of the measured temperature. The apparatus may comprise control circuitry to control a current in the at least one electromagnetic induction coil as a function of the measured temperature. The apparatus may comprise control circuitry to control the heater as a function of the measured temperature.

[0054] In the context of the present disclosure, the term “aerosol-generating article” is intended to mean an article comprising an aerosol-generating substrate that is configured to be used with an aerosol-generating device. The aerosol-generating substrate may comprise a nicotine-containing substance, e.g. tobacco. The article may comprise additional components such as a mouthpiece, an aerosol mixing portion, a filter portion, a flavour portion and so forth. An aerosol-generating article preferably has a rod-like or cylindrical form factor. An aerosol-generating article preferably has a constant cross-section along its length, which may be circular, elliptical or oval, but could also have other shapes, including polygonal. For the avoidance of doubt, the term “aerosolgenerating article” does not include or refer to aerosol spray cans or the like, but rather to articles that are associated with heat-not-burn reduced risk smoking products.

[0055] In the context of the present disclosure, the term “aerosol-generating substrate” is intended to mean a substrate that is capable of generating an aerosol when heated. Examples of aerosolgenerating substrates include tobacco cast leaf formed from a slurry of ground tobacco leaves and suitable binders, and also mixtures of nicotine with one or more of glycerine, guar gum, menthol, cloves, other flavourings, other agricultural products, or high retention material with nicotine content.

[0056] In the context of the present disclosure, the term “comminute” is intended to mean a process of physically breaking an article into smaller pieces, for example by grinding or shredding.

[0057] In the context of the present disclosure, the term “condensing separator” is intended to mean a reactor component adapted to receive a gaseous phase feed, and to cool the gaseous phase feed so as to cause one or more liquid phases to condense from the gaseous phase feed and to be separated therefrom.

[0058] In the context of the present disclosure, the term “fast pyrolysis” is intended to mean a pyrolysis process conducted with a short residence time in a pyrolysis reactor (of the order of seconds), a rapid heating rate, for example greater than 100 degrees Celsius per second, to a temperature range between 300 degrees Celsius and 700 degrees Celsius, preferably between 500 degrees Celsius and 700 degrees Celsius, in an inert atmosphere, for instance nitrogen, and the immediate cooling of the vaporization products in a condensing separator to extract bio-oil and syngas In the context of the present disclosure, the term “metallic susceptor” is intended to mean a substantially laminar metal element, for example in the form of a metal foil, that is disposed in or adjacent to an aerosol-generating substrate, and which can be heated by resistive or inductive heating so as to cause the aerosol-generating substrate to generate an aerosol.

[0059] In the context of the present disclosure, the term “pyrolysis” is intended to mean a process of heating an organic material, such as biomass, in the absence of oxygen. Because no oxygen is present combustion does not occur, rather the biomass thermally decomposes into combustible gases and bio-char. Most of these combustible gases can be condensed into a combustible liquid, called bio-oil, with some of the gases remaining in the gaseous phase, as syngas.

[0060] In the context of the present disclosure, the term “pyrolysis reactor” is intended to mean a reactor adapted to allow pyrolysis of a feedstock supplied to the reactor. A pyrolysis reactor will have a heating zone, a mechanism for heating feedstock in the heating zone, and a mechanism for extracting vaporization products and solid products of pyrolysis from the pyrolysis reactor.

[0061] The invention is defined in the claims. However, below there is provided a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

[0062] Example Ex1 : A method of processing waste consumable aerosol-generating articles by pyrolysis, the method comprising the steps of: feeding waste consumable aerosol-generating articles into a pyrolysis reactor, the aerosolgenerating articles comprising at least some aerosol-generating articles comprising an aerosolgenerating substrate with a metallic susceptor; heating the aerosol-generating articles in the pyrolysis reactor to a temperature sufficient to cause pyrolysis of non-metallic components of the aerosol-generating articles into gaseous products and char, wherein the temperature is less than a melting temperature of the metallic susceptors; extracting the gaseous products from the pyrolysis reactor and feeding the gaseous products to a condensing separator; and feeding the char from the pyrolysis reactor to a magnetic separator and separating the metallic susceptors from the char by applying a magnetic field.

[0063] Example Ex2: The method according to Example Ex1 , wherein at least some of the heat in the pyrolysis reactor is generated by applying an alternating electromagnetic field to the aerosol-generating articles so as to induce eddy currents in the metallic susceptors.

[0064] Example Ex3: The method according to Example Ex2, wherein the alternating electromagnetic field is applied by way of at least one induction coil.

[0065] Example Ex4: The method according to any preceding Example, wherein at least some of the heat in the pyrolysis reactor is generated by an electrical heater. Example Ex5: The method according to any preceding Example, wherein at least some of the heat in the pyrolysis reactor is generated by a gas heater.

[0066] Example Ex6: The method according to any preceding Example, wherein the temperature is less than 700 degrees Celsius; optionally wherein the temperature is less than 600 degrees Celsius; optionally wherein the temperature is above 400 degrees Celsius; optionally wherein the temperature is above 500 degrees Celsius; optionally wherein the temperature is between 500 degree Celsius and 600 degrees Celsius; optionally wherein the temperature is about 550 degrees Celsius.

[0067] Example Ex7: The method according to any preceding Example, wherein a substantially inert gas is supplied to the pyrolysis reactor during pyrolysis of the aerosol-generating articles.

[0068] Example Ex8: The method according to Example Ex7, wherein the substantially inert gas is supplied through at least one nozzle so as to cause the aerosol-generating articles in the pyrolysis reactor to form a fluidized bed.

[0069] Example Ex9: The method according to any preceding Example, wherein the condensing separator separates at least one of bio-oil and syngas from the gaseous products extracted from the pyrolysis reactor.

[0070] Example Ex10: The method according to any preceding Example, wherein the condensing separator is a fractional distillation separator.

[0071] Example Ex11 : The method according to any preceding Example, wherein the waste consumable aerosol generating articles are not comminuted prior to feeding into the pyrolysis reactor.

[0072] Example Ex12: The method according to any one of Examples Ex1 to Ex10, wherein prior to feeding the waste consumable aerosol-generating articles into the pyrolysis reactor, aerosolgenerating articles comprising a metallic susceptor are separated from aerosol-generating articles not comprising a metallic susceptor by way of a magnetic separator.

[0073] Example Ex13: The method according to Example Ex12, wherein the separated aerosolgenerating articles not comprising a metallic susceptor are comminuted to form a comminated feedstock.

[0074] Example Ex14: The method according to Example Ex13, wherein the separated aerosolgenerating articles not comprising a metallic susceptor are comminuted in a grinder.

[0075] Example Ex15: The method according to Example Ex13 or Ex14, wherein the comminuted feedstock is fed into the pyrolysis reactor together with the aerosol-generating articles comprising a metallic susceptor.

[0076] Example Ex16: The method according to Example Ex13 or Ex14, wherein the comminuted feedstock is fed into a separate pyrolysis reactor and processed separately from the aerosolgenerating articles comprising a metallic susceptor. Example Ex17: The method according to any preceding Example, wherein prior to feeding the waste consumable aerosol-generating articles into the pyrolysis reactor, a magnetic field is applied so as to cause the aerosol-generating articles comprising a metallic susceptor to align in a predetermined orientation.

[0077] Example Ex18: The method according to any preceding Example, wherein a stream of waste consumable aerosol-generating articles is passed through the pyrolysis reactor on a conveyor.

[0078] Example Ex19: The method according to Example Ex18, wherein the conveyor is a belt conveyor.

[0079] Example Ex20: The method according to Example Ex18, wherein the conveyor is an auger conveyor.

[0080] Example Ex21 : The method according to any one of Examples Ex18 to Ex20, wherein the conveyor carries the stream of aerosol-generating articles along a pathway.

[0081] Example Ex22: The method according to Example Ex21, wherein at least one electromagnetic induction coil is disposed adjacent to the pathway to induce eddy currents in the metallic susceptors in the stream of aerosol-generating articles.

[0082] Example Ex23: The method according to Example Ex22, wherein a plurality of flat electromagnetic induction coils is provided along the pathway, each coil having a normal axis directed towards the pathway.

[0083] Example Ex24: The method according to any one of Examples Ex21 to Ex23, wherein at least one heater is disposed adjacent to the pathway to heat the stream of aerosol-generating articles.

[0084] Example Ex25: The method according to any one of Examples Ex21 to Ex24, wherein a temperature in the pyrolysis reactor is measured with a temperature sensor.

[0085] Example Ex26: The method according to Example Ex25, wherein a speed of the conveyor is controlled as a function of the measured temperature.

[0086] Example Ex27: The method according to Example Ex25 or Ex26 depending through Example Ex22, wherein a current in the at least one electromagnetic induction coil is controlled as a function of the measured temperature.

[0087] Example Ex28: The method according to Example Ex25 or Ex26 depending through Example Ex24, wherein the heater is controlled as a function of the measured temperature.

[0088] Example Ex29: The method according to any preceding Example, wherein the waste consumable aerosol-generating articles are mixed with other biomass before or during feeding into the pyrolysis reactor.

[0089] Example Ex30: The method according to Example Ex29, wherein the other biomass comprises wood chips or wood pellets. Example Ex31 : The method according to Example Ex29 or Ex30, wherein the waste consumable aerosol-generating articles are mixed with other biomass in a mass ratio from 10:1 to 1 :10; preferably in a mass ratio from 1 :1 to 1 :10; more preferably in a mass ratio of about 1 :5.

[0090] Example Ex32: An apparatus for processing waste consumable aerosol-generating articles by pyrolysis, the apparatus comprising: a pyrolysis reactor configured to receive waste consumable aerosol-generating articles, the aerosol-generating articles comprising at least some aerosol-generating articles comprising an aerosol-generating substrate with a metallic susceptor; at least one heater configured to heat the aerosol-generating articles in the pyrolysis reactor to a temperature sufficient to cause pyrolysis of non-metallic components of the aerosolgenerating articles into gaseous products and char, wherein the temperature is less than a melting temperature of the metallic susceptors; a condensing separator configured to receive gaseous products from the pyrolysis reactor; and a magnetic separator configured to receive the char from the pyrolysis reactor and to separate the metallic susceptors from the char by applying a magnetic field.

[0091] Example Ex33: The apparatus according to Example Ex32, wherein the at least one heater comprises at least one electromagnetic induction coil configured to apply an alternating electromagnetic field to the aerosol-generating articles so as to induce eddy currents in the metallic susceptors.

[0092] Example Ex34: The apparatus according to Example Ex32 or Ex33, wherein the at least one heater comprises an electrical heater.

[0093] Example Ex35: The apparatus according to any one of Examples Ex32 to Ex34, wherein the at least one heater comprises a gas heater.

[0094] Example Ex36: The apparatus according to any one of Examples Ex32 to Ex35, wherein the temperature is less than 700 degrees Celsius; optionally wherein the temperature is less than 600 degrees Celsius; optionally wherein the temperature is above 400 degrees Celsius; optionally wherein the temperature is above 500 degrees Celsius; optionally wherein the temperature is between 500 degree Celsius and 600 degrees Celsius; optionally wherein the temperature is about 550 degrees Celsius.

[0095] Example Ex37: The apparatus according to any one of Examples Ex32 to Ex36, further comprising a source of a substantially inert gas configured to supply the substantially inert gas to the pyrolysis reactor during pyrolysis of the aerosol-generating articles.

[0096] Example Ex38: The apparatus according to Example Ex37, wherein the pyrolysis reactor comprises at least one nozzle through which the substantially inert gas is supplied so as to cause the aerosol-generating articles in the pyrolysis reactor to form a fluidized bed. Example Ex39: The apparatus according to any one of Examples Ex32 to Ex38, wherein the condensing separator is configured to separate at least one of bio-oil and syngas from the gaseous products extracted from the pyrolysis reactor.

[0097] Example Ex40: The apparatus according to any one of Examples Ex32 to Ex39, wherein the condensing separator is a fractional distillation separator.

[0098] Example Ex41 : The apparatus according to any one of Examples Ex32 to Ex40, further comprising a magnetic separator configured to separate aerosol-generating articles comprising a metallic susceptor from aerosol-generating articles not comprising a metallic susceptor prior to feeding the waste consumable aerosol-generating articles into the pyrolysis reactor.

[0099] Example Ex42: The apparatus according to Example Ex41 , further comprising a comminutor configured to comminute the separated aerosol-generating articles not comprising a metallic susceptor to form a comminuted feedstock.

[0100] Example Ex43: The apparatus according to Example Ex42, wherein the comminutor is a grinder.

[0101] Example Ex44: The apparatus according to Example Ex42 or Ex43, wherein the pyrolysis reactor is configured to receive the comminuted feedstock together with the aerosol-generating articles comprising a metallic susceptor.

[0102] Example Ex45: The apparatus according to Example Ex42 or Ex43, comprising a further pyrolysis reactor configured to receive the comminuted feedstock for processing separately from the aerosol-generating articles comprising a metallic susceptor.

[0103] Example Ex46: The apparatus according to any one of Examples Ex32 to Ex45, comprising a magnetic field generator configured to apply a magnetic field to cause the aerosol-generating articles comprising a metallic susceptor to align in a predetermined orientation prior to feeding the waste consumable aerosol-generating articles into the pyrolysis reactor.

[0104] Example Ex47: The apparatus according to any one of Examples Ex32 to Ex46, comprising a conveyor configured to convey a stream of waste consumable aerosol-generating articles through the pyrolysis reactor.

[0105] Example Ex48: The apparatus according to Example Ex47, wherein the conveyor is a belt conveyor.

[0106] Example Ex49: The apparatus according to Example Ex47, wherein the conveyor is an auger conveyor.

[0107] Example Ex50: The apparatus according to any one of Examples Ex47 to Ex49, wherein the conveyor is configured to carry the stream of aerosol-generating articles along a pathway.

[0108] Example Ex51 : The apparatus according to Example Ex50, wherein at least one electromagnetic induction coil is disposed adjacent to the pathway to induce eddy currents in the metallic susceptors in the stream of aerosol-generating articles. Example Ex52: The apparatus according to Example Ex51 , comprising a plurality of flat electromagnetic induction coils disposed adjacent to the pathway, each coil having a normal axis directed towards the pathway.

[0109] Example Ex53: The apparatus according to any one of Examples Ex50 to Ex52, comprising at least one heater disposed adjacent to the pathway to heat the stream of aerosol-generating articles.

[0110] Example Ex54: The apparatus according to any one of Examples Ex48 to Ex53, comprising a temperature sensor to measure a temperature in the pyrolysis reactor.

[0111] Example Ex55: The apparatus according to Example Ex54, comprising control circuitry to control a speed of the conveyor as a function of the measured temperature.

[0112] Example Ex56: The apparatus according to Example Ex54 or Ex55 depending through Example Ex51 , comprising control circuitry to control a current in the at least one electromagnetic induction coil as a function of the measured temperature.

[0113] Example Ex57: The apparatus according to Example Ex54 or Ex55 depending through Example Ex53, comprising control circuitry to control the heater as a function of the measured temperature.

[0114] Examples will now be further described with reference to the figures in which:

[0115] Figures 1 and 2 show, in perspective view and in cross-section, an aerosol-generating article in the form of a plug of sensorial medium including a metallic susceptor;

[0116] Figure 3 shows a schematic outline of an apparatus of a first embodiment of the present invention;

[0117] Figure 4 shows a schematic outline of an apparatus of a second embodiment of the present invention;

[0118] Figure 5 shows a magnetic field generator configured to apply a magnetic field to cause aerosol-generating articles comprising a metallic susceptor to align in a predetermined orientation:

[0119] Figure 6 shows a schematic outline of an apparatus of a third embodiment of the present invention;

[0120] Figure 7 shows a schematic outline of an apparatus of a fourth embodiment of the present invention;

[0121] Figure 8 is a process flow diagram for a process of the present invention;

[0122] Figure 9 is a process flow diagram for another process of the present invention; and

[0123] Figure 10 shows a fluidized bed pyrolysis reactor that may be used in the present invention.

[0124] With reference to Figures 1 and 2, there is shown an aerosol-generating article 1 in the form of a Sensorial Media (SM) plug of generally right-cylindrical shape (other shapes are possible), comprising an aerosol-generating substrate 2 wrapped with a wrapping material 4 and including a metallic susceptor 3 positioned centrally in an inside of the SM plug. It will be understood that aerosol-generating articles 1 may additionally comprise other plug components, such as Mouth Piece Filter (MPF) components and aerosol-cooling elements (not shown). Details of the construction of such aerosol-generating articles 1 are not of particular relevance, other than to note that aerosol-generating articles 1 intended to be processed by the present invention will include aerosol-generating articles 1 with metallic susceptors 3, optionally mixed with aerosolgenerating articles 1 without metallic susceptors 3. It is the presence of the metallic susceptors 3 that gives rise to particular problems, and which also enables operation of some aspects of the present invention. This is because some existing pyrolysis techniques, such as microwave pyrolysis or plasma pyrolysis, are incompatible with articles containing metallic susceptors.

[0125] Several pyrolysis techniques suitable for use with biomass, such as waste aerosolgenerating articles not comprising metallic susceptors, are known, including:

[0126] • Direct heating, in which heat is transferred directly to the biomass to be pyrolyzed through a medium such as combustion gases, hot air, or direct contact with a heated surface.

[0127] • Microwave pyrolysis, in which microwave radiation is used to generate heat within the biomass material itself, leading to rapid and uniform heating.

[0128] • Plasma pyrolysis, in which a plasma (ionized gas) torch is used to generate very high temperatures, effectively decomposing the biomass material into syngas (synthesis gas) and solid residue (char).

[0129] • Fast pyrolysis, which is characterized by rapid heating of the biomass to high temperatures for a short time.

[0130] For pyrolysis of organic materials such as dry leaves of plants or reconstituted tobacco, with the goal of recovering char, oil, and gas, it has been found that fast pyrolysis process is a good approach. The reason is that fast pyrolysis can be optimized for producing a high yield of bio-oil, along with char and syngas as by-products because, as compared to other pyrolysis techniques, fast pyrolysis uses rapid heating and cooling, thus preventing the further breakdown of bio-oil into gas and char.

[0131] A fine control of the pyrolysis conditions, such as the temperature and the heating time, as well as the evenness of heating of the feedstock, is advantageous so as to achieve a desired yield of syngas and bio-oil.

[0132] Pyrolysis may advantageously be performed in inert atmosphere (using an inert gas such as nitrogen) to limit undesirable combustion.

[0133] Waste treatment by pyrolysis of aerosol-generating articles containing metallic susceptors presents several challenges. Firstly, the presence of metal in the biomass can complicate the pyrolysis process, as metals have different properties compared to organic materials. Metals generally do not undergo pyrolytic decomposition like paper or leaves or other organic components, but instead will melt or vaporize at high temperatures, potentially leading to contamination of the resulting solid, gas and bio-oil products. Additionally, some metals when heated can react with other elements present in the biomass, forming undesirable compounds. For instance, at the very high temperatures involved in plasma pyrolysis, metallic susceptors will melt and / or vaporize, leading to contamination of the resulting products and damage to the pyrolysis reactor due to deposition and solidification of the molten metal in parts of the pyrolysis reactor. Moreover, metallic susceptors can interfere with the heating mechanism and make it difficult to control the thermal process during the pyrolysis reactions. For example, in the case of microwaves pyrolysis, the metallic susceptors could shield the surrounding biomass from the microwaves, creating uneven heating and potentially causing localized overheating or charring of the biomass. Additionally, the metallic susceptors may spark or arc when subjected to microwaves, creating a risk of unwanted ignition or chemical reactions that could further complicate the process.

[0134] Another problem is that the presence of metallic susceptors in the aerosol-generating articles means that the aerosol-generating articles should not be comminuted or ground prior to pyrolysis. This is because comminution will also comminute the metal susceptors into metal particles, which are difficult to separate from the output of the pyrolysis reactor and are even more likely to melt or vaporize at elevated temperatures.

[0135] Embodiments of the present invention seek to provide an efficient and effective method for the pyrolysis of waste aerosol-generating articles, for example comprising SM plugs, at least some of the aerosol-generating articles including metallic susceptors, to produce high-quality biooil products, as well as solid and gas byproducts.

[0136] Accordingly, a pyrolysis system may comprise the following components: i) a feeding mechanism to feed waste aerosol-generating articles, at least some of which contain a metallic susceptor, at a controlled rate into a pyrolysis reactor; ii) a pyrolysis reactor including a heating zone maintaining a substantially consistent temperature significantly below a melting point of the metallic susceptors, and preferably below 700 degrees Celsius; iii) a magnetic separator configured to act on solid material (char and metallic susceptors) remaining after the pyrolysis, to separate the char from the metal susceptors; iv) a cooling and separation system configured to act on vaporization products from the pyrolysis reactor, so as to cooled and condense the vaporization products into liquid bio-oil products, gas products, and possibly residual solids.

[0137] Such a pyrolysis system may offer a sustainable solution for converting waste aerosolgenerating articles, at least some of which comprise a metal susceptor, into separated components: char, metallic susceptors, bio-oil and syngas, while minimizing waste generation and environmental impact.

[0138] The pyrolysis temperature in the pyrolysis reactor is preferably no more than 700 degrees Celsius, preferably between about 500 degrees Celsius and 600 degrees Celsius, ideally about 550 degrees Celsius. This temperature range has been found to provide an optimal mass yield percentage for waste aerosol-generating articles, at least some of which comprise a metal susceptor, in relation to a duration of pyrolysis.

[0139] Standard pyrolysis temperatures are typically between 300 degrees Celsius and 800 degrees Celsius. Metal melting points are often above 800 degrees Celsius, but care needs to be taken with alloys, where the melting point temperature is usually lower than the melting point temperatures of the elemental metals forming the alloy. Accordingly, it is preferable that the pyrolysis temperature in the pyrolysis reactor is kept significantly below 800 degrees Celsius so as to avoid melting or vaporization of the metallic susceptors, but still high enough to facilitate fast pyrolysis of organic materials.

[0140] The pyrolysis system may be configured to allow the transportation of biomass through the pyrolysis reactor. For example, a dedicated conveyor may transport the biomass into the pyrolysis reactor and through the heating zone, exposing the biomass to the temperatures required for pyrolysis. The residual solids (for example, char and metallic susceptors) may be transported on the conveyor to the magnetic separator so that the metallic susceptors can be separated from char.

[0141] Referring now to Figure 3, there is shown a schematic overview of a first embodiment, the process going from left to right. The may comprise a feeding mechanism including a storage hopper 40 into which aerosol-generating articles 30, some of which include metallic susceptors, are loaded begore being conveyed at a controlled rate along a conveyor 41 to a pyrolysis reactor 60.

[0142] The pyrolysis reactor 60 may include a belt conveyor 50 to transport the waste aerosolgenerating articles 30 into an enclosed chamber 51 (shown in dashed lines for the sake of clarity). The enclosed chamber 51 includes a heating zone furnace incorporating electrical heaters 52, for example electrical resistance heaters, which serve to heat the waste aerosol-generating articles, as indicated at 31. It will be noted that the waste aerosol-generating articles are progressively heated as they travel through the enclosed chamber 51 from left to right, becoming hotter with increased residence time in the heating zone.

[0143] Vaporization products from the pyrolysis reactor 60 are extracted by way of an exhaust and are directed through a condensing separator 61. The condensing separator 61 may separate syngas 33 and bio-oil 32 from the vaporization products of the pyrolysis reactor 60. The condensing separator 61 may also allow a solid fraction to be separated from the vaporization products of the pyrolysis reactor 60.

[0144] Solid products from the pyrolysis reactor 60, namely char and metallic susceptors indicated generally at 34, are carried by the conveyor 50 to a magnetic separator 70. The magnetic separator 70 may comprise a belt conveyor and an electromagnet 71 . The belt conveyor of the magnetic separator can cause char 35 to be ejected into a first container 35, while the electromagnetic 71 will tend to keep the metallic susceptors 36 on the belt conveyor until the belt of the belt conveyor moves away from the electromagnet 71 , allowing the metallic susceptors 36 to fall into a second container 73.

[0145] In the embodiment of Figure 3, the heating zone furnace of the enclosed chamber 51 of the pyrolysis reactor 60 is heated by electrical heaters, or alternatively by a gas heater (for example, a gas flame heater).

[0146] The speed of the conveyors 41 and 50, as well as the current supplied to the electrical heaters 52, may be controlled, for example automatically, in order to adjust pyrolysis parameters. A temperature sensor (not shown) may be provided in the enclosed chamber 51 to measure a temperature in the heating zone, and control circuitry (not shown) may adjust the speed of one or other or both of the conveyors 41 and 50, or the current supplied to the electrical heaters 52, or a combination of both, so as to maintain a desired temperature within the heating zone. This may help to promote efficient pyrolysis without unwanted combustion.

[0147] A sensor may be provided at one or other or both of the conveyors 41 , 50 so as to monitor an amount or number or mass of aerosol-generating articles 30 being fed into the enclosed chamber 51 of the pyrolysis reactor 60. This can allow the heating parameters to be adjusted accordingly, since a greater bulk mass of aerosol-generating articles 30 will require more heat for efficient pyrolysis than a smaller bulk mass of aerosol-generating articles 30.

[0148] An alternative second embodiment is shown in schematic outline in Figure 4, the process going from left to right. The second embodiment is generally similar to the first embodiment of Figure 3, with like parts being labelled as per Figure 3. In contrast to the first embodiment of Figure 3, the embodiment of Figure 4 comprises at least one electromagnetic induction coil 53, and preferably a plurality of electromagnetic induction coils 53, around the heating zone of the enclosed space 51. The electromagnetic induction coils 53 are configured so as to induce eddy currents in any metallic susceptors that are present in the waste aerosol-generating articles 30 on the belt conveyor 50 passing through the enclosed chamber 51 , as indicated generally at 31. The induced eddy currents will cause the metallic susceptors to heat up due to the Joule effect, and this internal heating from within the aerosol-generating articles 30 may supplement or replace external heating from the electrical heaters 52 (or equivalent gas heaters).

[0149] The electromagnetic induction coils 53 may be configured as flat coils (“pancake coils”), each of which has a line normal to the plane of the coil pointing towards the metallic susceptors on the belt conveyor 50 passing through the heating zone of the enclosed chamber 51. The electromagnetic induction coils 53 may be incorporated in the belt conveyor 50. It may be desirable for the electromagnetic induction coils 53 to be close to the metallic susceptors so as to allow efficient inductive coupling and heating. This may also allow smaller electromagnetic induction coils 53 to be used than if the electromagnetic induction coils 53 is located further away from the metallic susceptors. The speed of the conveyors 41 and 50, as well as the current supplied to the electromagnetic induction coils 53 (and optionally the current supplied to the electrical heaters 52 if present), may be controlled, for example automatically, in order to adjust pyrolysis parameters. A temperature sensor (not shown) may be provided in the enclosed chamber 51 to measure a temperature in the heating zone, and control circuitry (not shown) may adjust the speed of one or other or both of the conveyors 41 and 50, or the current supplied to the electromagnetic induction coils 53, or the current supplied to the electrical heaters 52 (if present) or a combination of two or more of these, so as to maintain a desired temperature within the heating zone. This may help to promote efficient pyrolysis without unwanted combustion.

[0150] A sensor may be provided at one or other or both of the conveyors 41 , 50 so as to monitor an amount or number or mass of aerosol-generating articles 30 being fed into the enclosed chamber 51 of the pyrolysis reactor 60. This can allow the heating parameters to be adjusted accordingly, since a greater bulk mass of aerosol-generating articles 30 will require more heat for efficient pyrolysis than a smaller bulk mass of aerosol-generating articles 30.

[0151] One advantage of using electromagnetic induction to cause inductive heating of the metallic susceptors within the waste aerosol-generating articles 30 is that a desired pyrolysis temperature may be achieved more rapidly, thus facilitating fast pyrolysis. Another advantage is that electromagnetic induction heating can help generate heat more uniformly throughout a mass of waste aerosol-generating articles 30, and can increase control of the overall temperature, since the magnitude of the eddy currents in the metallic susceptors can be instantly adjusted by adjusting the current supplied to the electromagnetic induction coils 53, thus allowing the heat generated by the eddy currents to be adjusted.

[0152] The belt conveyor 50 in both the Figure 3 and Figure 4 embodiments may comprise an open mesh belt so as to facilitate distribution of heat (for example by radiation, or by convention, or by both radiation and convection) throughout the heating zone of the enclosed chamber 51 .

[0153] The condensing separator 61 may comprise any appropriate condensing separator apparatus, for example a Liebig condenser, a coil condenser, a fractional distillation column or other condenser. The condensing separator 61 may comprise a filter (not shown) to separate out any solid residue.

[0154] Optionally, as shown in Figure 5, the waste aerosol-generating articles 30 on the belt conveyor 50 may pass through a magnetic field generator 54 (for example, an electromagnet) that generates a magnetic field 540 that acts to align the magnetic susceptors of the waste aerosol-generating articles 30 on the belt conveyor 50, as indicated generally at 300. The alignment preferably takes place before the waste aerosol-generating articles 30 enter the heating zone of the enclosed chamber 51. The metallic susceptors may be aligned in a direction that promotes the most efficient inductive coupling with the electromagnetic induction coils 53 in the heating zone. Referring now to Figure 6, there is shown a schematic overview of a third embodiment, the process going from left to right. The third embodiment employs an auger conveyor comprising a rotating helical screw 55 connected to a motor 56, and rotation of the rotating helical screw 55 by the motor 56 will cause waste aerosol-generating articles 30, some of which contain a metallic susceptor, to be fed from a hopper 42 and pass through an enclosed chamber 51 of a pyrolysis reactor. An inert gas, for example nitrogen, can be supplied to the enclosed chamber 51 from a supply 57 of inert gas. The enclosed chamber 51 is provided with heaters, for example electrical heaters 52 or gas heaters, so as to define a heating zone in the pyrolysis reactor.

[0155] A distal end of the pyrolysis reactor is provided with a manifold 58 to allow vaporization products of pyrolysis to be passed to a condensing separator 61 , and for solid products of pyrolysis 34 (for example, char and metallic susceptors) to be passed to a magnetic separator 70. The condensing separator 61 and the magnetic separator 70 may be similar to those previously described in relation to Figure 3.

[0156] The auger conveyor allows continuous flow of waste aerosol-generating articles 30 through the heating zone of the pyrolysis reactor. The rotating helical screw 55, as well as propelling the waste aerosol-generating article feedstock through the heating zone, will also continuously mix the feedstock, thus promoting uniform heat transfer and better thermal contact between the waste aerosol-generating articles 30. The rotating helical screw 55 helps to reduce the incidence of hotspots and improve pyrolysis efficiency. Furthermore, the auger conveyor is well-suited to handle feedstock having the size of waste aerosol-generating articles 30 and enable continuous feeding of the feedstock and removal of the pyrolysis products, allowing for higher productivity and easier scale-up compared for instance to batch processes.

[0157] The auger conveyor allows for direct or indirect heating along the length of the heating zone of the enclosed chamber 51 , and the residence time of the feedstock in the heating zone can be finely adjusted by appropriate selection and control of the speed of rotation of the helical screw 55. Additionally, the pitch of the helical screw 55 may be selected to provide a desired linear speed of translation as a function of rotational speed.

[0158] The auger conveyor is also advantageous since the rotational motion of the helical screw will tend to apply shearing forces to the waste aerosol-generating articles 30, helping to separate the metallic susceptors 3, the aerosol-generating substrates 2 and the wrappers 4 to help maximise heat transfer and efficient pyrolysis.

[0159] Referring now to Figure 7, there is shown a schematic overview of a fourth embodiment, the process going from left to right. The fourth embodiment is similar to the third embodiment of Figure 3, except that electromagnetic induction coils 53 are additionally (or alternatively) provided around the enclosed chamber 51 so as to induce eddy currents in metallic susceptors in the waste-aerosol generating article feedstock 30, in a similar manner to the embodiment of Figure 4. As in the embodiment of Figure 4, the electromagnetic induction coils 53 may comprise an array of flat induction coils arranged on an inner or outer surface of the enclosed chamber 51 of the pyrolysis reactor so as to generate magnetic fields points towards (and outwardly from) the inner part of the heating zone.

[0160] Through appropriate selection and control of at least one of the heaters 52, the electromagnetic induction coils 53, the rotational speed of the helical screw 55, the pitch of the helical screw 55, the cross-sectional area of the heating zone of the enclosed chamber 51 , and the length of the enclosed chamber 51 , it is possible to establish a heating profile adapted to promote fast pyrolysis of waste aerosol-generating articles 30, some of which comprise a metallic susceptor. For example, a residence time of the feedstock (in the form of waste aerosolgenerating articles 30) in the heating zone could be around 10 seconds, and the temperature reached using both the conventional heating means (e.g., resistance heating) and electromagnetic induction heating may be between about 500 degrees Celsius and 700 degrees Celsius.

[0161] The two different kinds of heating, electromagnetic induction heating and conventional pyrolysis heating, for example by way of electrical heating or gas heating, could be sequential instead of simultaneous and could take place inside the same pyrolysis reactor or in successive pyrolysis reactors. This may have the advantage that the different heating mechanisms do not interfere with each other, and it may facilitate control and management of heating profiles for efficient pyrolysis.

[0162] For example, as illustrated in the process flow diagram of Figure 8, the feedstock of waste aerosol-generating articles could first pass through a fixed field of an electromagnet (as shown in Figure 5) in order to align the metallic susceptors before passing the feedstock on a linear, nonstirring conveyor (for example, a belt conveyor) through a first pyrolysis reactor configured to generate heat only by electromagnetic induction of eddy currents in the metallic susceptors, while collecting vaporization products in a first condensing separator for separation into bio-oil and syngas. The feedstock could then be passed to a second pyrolysis reactor, either with a belt conveyor or an auger conveyor, and configured to heat the feedstock by way of electrical or gas heaters, optionally also to heat the feedstock by electromagnetic induction of eddy currents in the metallic susceptors, while collecting further vaporization products in a second condenser separator for separation into bio-oil or syngas. The remaining solid pyrolysis products, namely a mixture of char and metallic susceptors, is then passed to a magnetic separator in order to separate the metallic susceptors from the char.

[0163] Alternatively, the first pyrolysis reactor may utilize electrical or gas heating, while the second pyrolysis reactor may utilize electromagnetic induction heating.

[0164] In all of the embodiments above, the waste aerosol-generating article feedstock could be mixed with other biomass, for example wood or paper, in order to enhance the pyrolysis process. Preferably, the pyrolysis process is a fast pyrolysis process, by which is meant a pyrolysis process conducted with a short residence time in the heating zone of the pyrolysis reactor (of the order of seconds), a rapid heating to a temperature range between 300 degrees Celsius and 700 degrees Celsius, preferably between 500 degrees Celsius and 700 degrees Celsius, in an inert atmosphere, for instance nitrogen, and the immediate cooling of the vaporization products in a condensing separator to extract bio-oil and syngas.

[0165] With reference to Figure 9, there is shown a process flow diagram of an embodiment in which waste aerosol-generating articles are subjected to an initial magnetic separation process so as to separate waste aerosol-generating articles comprising metallic susceptors from waste aerosol-generating articles not comprising metallic susceptors. The magnetic separation process may employ a magnetic separator similar to the magnetic separator 70 shown in Figures 3, 4, 6 and 7. The waste aerosol-generating articles not comprising metallic susceptors may be comminuted in a grinder so as to form a comminuted feedstock that does not contain metal particles. The waste aerosol-generating articles comprising metallic susceptors may optionally pass through a static magnetic field, for example generated by an electromagnet as shown in Figure 5, to align the metallic susceptors in a desired direction, before passing the waste aerosolgenerating articles comprising metallic susceptors through a pyrolysis reactor configured for electromagnetic induction heating and optionally also electrical or gas heating. Bio-oil and syngas are extracted from the vaporization products of the pyrolysis process, and the solid residue comprising char and metallic susceptors is then subjected to a magnetic separation process in order to separate the metallic susceptors from the char. The comminuted waste aerosolgenerating articles not comprising metallic susceptors can be fed, in the form of biomass, into the same pyrolysis reactor as the waste aerosol-generating articles comprising metallic susceptors. Alternatively, the comminuted waste aerosol-generating articles not comprising metallic separators can be fed to a separate pyrolysis reactor configured for electrical heating or gas heating, with vaporization products being passed to a condensing separator for separation of biooil and syngas, and solid residue in the form of char being collected for disposal.

[0166] Figure 10 shows a direct heating (e.g. electrical resistance heating or gas flame heating) pyrolysis process using a fluidized bed pyrolysis reactor 13. Such a fluidized bed pyrolysis reactor 13 may be used with a feedstock of comminuted waste aerosol-generating articles not comprising metallic susceptors. Waste aerosol-generating articles not comprising metallic susceptors, indicated generally at 10, are comminuted in a grinder 11 , and the comminuted feedstock 12 is then conveyed to the fluidized bed pyrolysis reactor 13. The reactor 13 may be a vertically- oriented cylindrical chamber having a perforated distributor plate 14, through which an inert gas 15 such as nitrogen is injected upwardly under pressure so as to cause the comminuted feedstock to fluidify, as indicated generally at 16. The fluidized feedstock 16 is heated to an appropriate pyrolysis temperature by way of electrical heaters or gas heaters (not shown) before passing into a vortex separator 17, where heavier solid components such as char will fall to the bottom for collection at 18, while lighter vaporization products will pass out of the top of the vortex separator 17 into a condensing separator 19 for separation into syngas 21 and bio-oil 20.

[0167] For the purpose of the present description and of the appended claims, except where otherwise indicated, all numbers expressing amounts, quantities, percentages, and so forth, are to be understood as being modified in all instances by the term "about". Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein. In this context, therefore, a number A is understood as A ± 5% of A. Within this context, a number A may be considered to include numerical values that are within general standard error for the measurement of the property that the number A modifies. The number A, in some instances as used in the appended claims, may deviate by the percentages enumerated above provided that the amount by which A deviates does not materially affect the basic and novel characteristic(s) of the claimed invention. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein.

Claims

25 / 28CLAIMS:

1. A method of processing waste consumable aerosol-generating articles by pyrolysis, the method comprising the steps of: feeding waste consumable aerosol-generating articles into a pyrolysis reactor, the aerosol-generating articles comprising at least some aerosol-generating articles comprising an aerosol-generating substrate with a metallic susceptor; heating the aerosol-generating articles in the pyrolysis reactor to a temperature sufficient to cause pyrolysis of non-metallic components of the aerosol-generating articles into gaseous products and char, wherein the temperature is less than a melting temperature of the metallic susceptors; extracting the gaseous products from the pyrolysis reactor and feeding the gaseous products to a condensing separator; and feeding the char from the pyrolysis reactor to a magnetic separator and separating the metallic susceptors from the char by applying a magnetic field; wherein at least some of the heat in the pyrolysis reactor is generated by applying an alternating electromagnetic field to the aerosol-generating articles so as to induce eddy currents in the metallic susceptors.

2. The method according to claim 1 , wherein the alternating electromagnetic field is applied by way of at least one induction coil.

3. The method according to any preceding claim, wherein at least some of the heat in the pyrolysis reactor is generated by an electrical heater.

4. The method according to any preceding claim, wherein the temperature is less than 700 degrees Celsius; optionally wherein the temperature is less than 600 degrees Celsius; optionally wherein the temperature is above 400 degrees Celsius; optionally wherein the temperature is above 500 degrees Celsius; optionally wherein the temperature is between 500 degree Celsius and 600 degrees Celsius; optionally wherein the temperature is about 550 degrees Celsius.

5. The method according to any preceding claim, wherein the condensing separator separates at least one of bio-oil and syngas from the gaseous products extracted from the pyrolysis reactor.

6. The method according to any preceding claim, wherein prior to feeding the waste consumable aerosol-generating articles into the pyrolysis reactor, aerosol-generating articlescomprising a metallic susceptor are separated from aerosol-generating articles not comprising a metallic susceptor by way of a magnetic separator.

7. The method according to any preceding claim, wherein prior to feeding the waste consumable aerosol-generating articles into the pyrolysis reactor, a magnetic field is applied so as to cause the aerosol-generating articles comprising a metallic susceptor to align in a predetermined orientation.

8. The method according to any preceding claim, wherein a stream of waste consumable aerosol-generating articles is passed through the pyrolysis reactor on a belt conveyor.

9. The method according to any one of claims 1 to 7, wherein a stream of waste consumable aerosol-generating articles is passed through the pyrolysis reactor on a belt conveyor.

10. An apparatus for processing waste consumable aerosol-generating articles by pyrolysis, the apparatus comprising: a pyrolysis reactor configured to receive waste consumable aerosol-generating articles, the aerosol-generating articles comprising at least some aerosol-generating articles comprising an aerosol-generating substrate with a metallic susceptor; at least one heater configured to heat the aerosol-generating articles in the pyrolysis reactor to a temperature sufficient to cause pyrolysis of non-metallic components of the aerosolgenerating articles into gaseous products and char, wherein the temperature is less than a melting temperature of the metallic susceptors; a condensing separator configured to receive gaseous products from the pyrolysis reactor; and a magnetic separator configured to receive the char from the pyrolysis reactor and to separate the metallic susceptors from the char by applying a magnetic field; wherein the at least one heater comprises at least one electromagnetic induction coil configured to apply an alternating electromagnetic field to the aerosol-generating articles so as to induce eddy currents in the metallic susceptors.

11. The apparatus according to claim 10, wherein the at least one heater comprises an electrical heater.

12. The apparatus according to claim 10 or 11 , wherein the temperature is less than 700 degrees Celsius; optionally wherein the temperature is less than 600 degrees Celsius; optionally wherein the temperature is above 400 degrees Celsius; optionally wherein the temperature isabove 500 degrees Celsius; optionally wherein the temperature is between 500 degree Celsius and 600 degrees Celsius; optionally wherein the temperature is about 550 degrees Celsius.

13. The apparatus according to any one of claims 10 to 12, further comprising a magnetic separator configured to separate aerosol-generating articles comprising a metallic susceptor from aerosol-generating articles not comprising a metallic susceptor prior to feeding the waste consumable aerosol-generating articles into the pyrolysis reactor.

14. The apparatus according to any one of claims 10 to 13, comprising a magnetic field generator configured to apply a magnetic field to cause the aerosol-generating articles comprising a metallic susceptor to align in a predetermined orientation prior to feeding the waste consumable aerosol-generating articles into the pyrolysis reactor.

15. The apparatus according to any one of claims 10 to 14, comprising an auger conveyor configured to convey a stream of waste consumable aerosol-generating articles through the pyrolysis reactor.

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