Patent Description:
Further, the present invention relates to a method for treatment of polymer waste.

Polymers are used in a wide variety of products. The polymers are typically acquired through petroleum resources, which are considered non-renewable. In this connection, the need for a sustainable supply of raw material has arisen, as accumulation of polymer waste has been recognized as an environmental problem. As a consequence, polymer waste is often collected and sorted for recycling or thermal decomposition purposes. Environmental problems can be reduced by subsequent polymer waste material treatment and re-use of at least a part of the material.

For example, polymer waste material can be treated by pyrolysis, i.e. by thermal decomposition of the polymer waste material at elevated temperatures in an inert atmosphere, in order to obtain a product comprising a gas from at least partially pyrolyzed polymer waste. Such treatment may, for example, take place in a reactor, such as a rotary kiln reactor, into which polymer waste is fed. Typically, a carrier gas is further utilized to promote a flow, increase a flow velocity and to flush the process train of a gas from at least partially pyrolyzed polymer waste towards another section for aftertreatment. Nitrogen is a commonly used carrier gas, for instance. Other examples of a carrier gas are carbon dioxide or methane.

Document <CIT> discloses a reactor and its internals used for the thermal processing of a liquid mixture. The reactor comprises a hollow chamber comprising a plurality of spaces. The reactor further comprises a lance having a plurality of feed outlets for feeding organic liquids into each of the plurality of spaces. Additionally, the reactor comprises a heating system capable of heating each of the plurality of spaces.

Document <CIT> further describes a system comprising a hollow reaction compartment, a heating system capable of controlling temperature conditions in the reaction compartment, a lance for feeding a feed into the reaction compartment and an injector for injecting a gas into the reaction compartment.

In view of the above, it would be beneficial to provide a system and method for treatment of polymer waste.

According to a first aspect of the present invention, there is provided a system comprising a hollow chamber comprising a first space and a second space, wherein the second space is rotatable or the first space and the second space are rotatable, wherein the hollow chamber comprises a barrier between the first space and the second space, a heating system configured to heat the second space or to individually heat the first space and the second space, a polymer waste feed lance having at least one polymer waste feed outlet, wherein the polymer waste feed lance extends within the hollow chamber at least through the first space, and wherein the system is configured to feed polymer waste only into the second space via the at least one polymer waste feed outlet, and wherein an opening is provided between the barrier and the polymer waste feed lance, and at least one sweep fluid injector capable of injecting at least one sweep fluid into the first space or into the first space and into the second space in order to form a fluid flow towards at least one gas outlet for collecting a product comprising the at least one sweep fluid and a gas from at least partially pyrolyzed polymer waste.

According to a second aspect of the present invention, there is provided a method comprising providing a hollow chamber comprising a first space and a second space, wherein the second space is rotated or the first space and the second space are rotated, heating the second space or individually heating the first space and the second space, providing a polymer waste feed lance having at least one polymer waste feed outlet, wherein the polymer waste feed lance extends within the hollow chamber at least through the first space, and feeding polymer waste only into the second space via the at least one polymer waste feed outlet, wherein an opening is provided between the barrier and the polymer waste feed lance, injecting at least one sweep fluid by at least one sweep fluid injector into the first space or into the first space and into the second space in order to form a fluid flow towards at least one gas outlet for collecting a product comprising the at least one sweep fluid and a gas from at least partially pyrolyzed polymer waste.

Various embodiments of the second aspect may comprise at least one feature from the following bulleted list:.

Considerable advantages are obtained by certain embodiments of the invention. In particular, a system and method for treatment of polymer waste are provided. The system comprises a hollow chamber having a first space and a second space, wherein the second space is rotatable or the first space and the second space are rotatable. A sweep fluid can be injected into the first space and polymer waste material can be fed into the second space. A product comprising the at least one sweep fluid and a gas from at least partially pyrolyzed polymer waste is collected during operation of the reactor for aftertreatment. According to certain embodiments, a fluid flow is formed due to a pressure gradient between the first space and the second space, and thus a blowback of the gas from at least partially pyrolyzed polymer waste can be avoided. Use of a condensable gas, steam or water as a sweep fluid is beneficial for aftertreatment purposes, as the sweep fluid can be easily separated or removed from the product by condensation in the aftertreatment process. Removal of the sweep fluid or carrier gas not contributing to a liquid product yield in polymer waste pyrolysis can improve the recovery of hydrocarbons. Use of hydrocarbons or use of hydrocarbons containing water as a sweep fluid is beneficial for reducing the water content in the system, thus reducing the need for water separation and waste water management at a later stage. Maximizing the liquid product recovery is highly important for the techno-economic performance and sustainability of polymer waste pyrolysis processes. Additionally, the condensation train of a polymer waste material pyrolysis system is typically designed to remove pyrolytic water, and therefore feeding water or steam into the first space of the reactor does not bring significant additional complexity into the process.

In <FIG> a schematic view of a system <NUM> in accordance with at least some embodiments of the present invention is illustrated. The system <NUM> comprises a so-called reactor or rotary kiln reactor, particularly for thermal decomposition of materials at elevated temperatures in presence of no or low amount of oxygen to avoid combustion of hydrocarbons. This process is also called pyrolysis.

Particularly, the system <NUM> comprises a hollow chamber <NUM> comprising a first space <NUM> and a second space <NUM>. Both the first space and the second space are rotatable. The system <NUM> is configured to treat polymer waste <NUM>. In this document, the term "polymer waste" relates to a material that comprises mainly a polymer material. For example, impurities in the polymer material may be present. Typically, the polymer waste <NUM> is material collected for recycling or thermal decomposition purposes. An example polymer waste feedstock used according to certain embodiments includes polyethylene with varying amounts of at least one of: polypropylene, polystyrene and other components such as polyamides, polyethylene terephthalate and polyvinyl chloride. Polymer waste feedstocks may be contaminated with minor traces of impurities that originate e.g. from biomass.

The hollow chamber <NUM> is typically in the form of an elongated hollow cylinder. The term "elongated" means that a length of the hollow cylinder is substantially greater than a diameter of the hollow cylinder. For example, the length of the hollow cylinder may be <NUM> and the diameter of the hollow cylinder may be <NUM>. The hollow chamber <NUM> is typically made of a metal or metal alloy. The entire hollow chamber <NUM> is configured to be rotated around an axis of rotation A. The axis of rotation A is typically orientated horizontally or substantially horizontally. The term "axis orientated horizontally" means an axis that is orientated perpendicular to a gravity vector or perpendicular to the normal on the surface of the Earth. Similarly, the term "axis orientated substantially horizontally" means an axis that is tilted a few degrees, for example less than <NUM> degrees, from the axis that is orientated perpendicular to a gravity vector or perpendicular to the normal on the surface of the Earth. The rotational speed of the entire hollow chamber <NUM> may be, for example, in the range between <NUM> and <NUM> revolutions per minute (rpm), for example in the range between <NUM> and <NUM> rpm. The first space <NUM> and the second space <NUM> rotate both simultaneously in the embodiment of <FIG>. According to other embodiments, only the second space <NUM> is rotated or both the first space <NUM> and the second space are individually rotated as described in connection with <FIG>.

The system further comprises a heating system <NUM> configured to individually heat the first space <NUM> and the second space <NUM>. The heating system <NUM> is typically arranged external to the walls of the hollow chamber <NUM> as indicated by arrows <NUM>. Heating of the first space <NUM> and the second space <NUM> takes place by increasing a wall temperature of the rotatable hollow chamber <NUM> by contacting the wall with heating gas, in particular a lateral area of the rotatable hollow chamber, from ambient temperature to a temperature in the range between <NUM> and <NUM>. Typically, the wall temperature in the lateral area of the first space <NUM> is different from the wall temperature in the lateral area of the second space <NUM>. As a consequence, different temperatures can be provided within the first space <NUM> and within the second space <NUM>, if required. The temperature within the first space <NUM> may be, for example, <NUM> and the temperature within the second space <NUM> may be, for example, <NUM>. Typically, the temperature within the second space <NUM> is greater than the temperature within the first space <NUM>. In other words, the system <NUM> is configured to adjust the temperature within the first space <NUM> and the temperature within the second space <NUM> by means of the heating system <NUM>. The temperature within the second space <NUM> is typically greater than a decomposition temperature of a polymer waste material. An example of a heating system <NUM> for the shown embodiment is illustrated in <FIG>. According to another embodiment of the present invention, only the second space <NUM> is heated as shown in <FIG>. According to a further embodiment of the present invention, the wall of the second space <NUM> can be divided into sub-zones or heating zones which can be heated individually as shown in <FIG>.

The system <NUM> yet further comprises a polymer waste feed lance <NUM> having at least one polymer waste feed outlet <NUM>. The polymer waste feed lance <NUM> is stationary, i.e. the polymer waste feed lance <NUM> is not configured to rotate and the rotatable hollow chamber <NUM> is configured to rotate around the polymer waste feed lance <NUM>. The polymer waste feed lance <NUM> may be, for example, in the form of a hollow cylinder. A center axis of the polymer waste feed lance <NUM> is typically arranged or orientated coaxially with the axis of rotation A. The polymer waste feed lance <NUM> is typically made of metal or a metal alloy. The polymer waste feed lance <NUM> extends within the hollow chamber <NUM> at least through the first space <NUM>. The polymer waste feed lance <NUM> may additionally extend partially into the second space <NUM> as shown in <FIG>. The system <NUM> is configured to feed polymer waste <NUM> into the second space <NUM> via the at least one polymer waste feed outlet <NUM>. The polymer waste feed lance <NUM> is comprised by or coupled to a feeding system (not shown). The feeding system is typically an extrusion-type feeding system. The polymer waste <NUM> is (predominantly) pre-molten so that the feed is converted into a flowable form allowing travelling through the polymer waste feed lance <NUM>.

The polymer waste <NUM> material fed into the second space <NUM> via the at least one polymer waste feed outlet <NUM> of the polymer waste feed lance <NUM> falls on a heated inner surface <NUM> of the rotatable hollow chamber <NUM> due to gravity. The rotation of the hollow chamber <NUM> causes the polymer waste material <NUM> to distribute over at least a part of the inner surface <NUM> of the chamber <NUM> in the second space <NUM>. Distribution of the polymer waste material <NUM> over at least a part of the inner surface <NUM> of the chamber <NUM> in the second space <NUM> may be improved by tilting the rotatable hollow chamber <NUM> a few degrees, for example <NUM> degrees to <NUM> degrees from the horizontal axis. In such a configuration, the rotatable hollow chamber <NUM> is arranged substantially horizontally.

The high temperature wall of the hollow chamber <NUM> causes thermal decomposition of the polymer waste material <NUM> within the second space <NUM>, thus converting the polymer waste material <NUM> into a gas <NUM> from at least partially pyrolyzed polymer waste and a residue. The residue may comprise inorganics or inorganic contaminants, for instance. The rotatable hollow chamber <NUM> typically comprises a residue outlet <NUM> at a rear end <NUM> of the chamber <NUM>.

The hollow chamber <NUM> further comprises a barrier <NUM> or seal between the first space <NUM> and the second space <NUM>. The barrier <NUM> or seal is configured to allow a fluid flow, particularly a gas flow, from the first space <NUM> to the second space <NUM>. An opening <NUM> is provided between the barrier <NUM> and the lance <NUM>. The opening <NUM> may be permeable for the sweep fluid to flow into the direction from the first space <NUM> into the second space <NUM>, but impermeable into the opposite direction. The barrier <NUM> or seal may alternatively also comprise features allowing gas flow, i. , a plurality of perforations, for instance. The barrier <NUM> is typically made of metal, a metal alloy or a high temperature resistant fabric.

The system <NUM> even further comprises at least one sweep fluid injector <NUM> capable of injecting at least one sweep fluid <NUM> into the first space <NUM>. Within the embodiments shown in <FIG>, the term "sweep fluid injector" means a specific unit for injecting the at least one sweep fluid <NUM> into the first space <NUM>. Such sweep fluid injector <NUM> may, for example, comprise at least one sweep fluid injection lance extending into the first space <NUM>. Such sweep fluid injector <NUM> may, for example, comprise a nozzle. Alternatively, the term "sweep fluid injector" may also mean a simple opening in the system <NUM> through which the at least one sweep fluid <NUM> can be guided into the first space <NUM>. The system <NUM> may also comprise a plurality of sweep fluid injectors <NUM>, wherein each sweep fluid injector <NUM> is capable of injecting a different sweep pluid <NUM> into the first space <NUM>. One sweep fluid injector <NUM> may be, for example, arranged to inject a condensable gas into the first space <NUM> and another sweep fluid injector <NUM> may be, for example, arranged to inject a non-condensable gas into the first space <NUM>, such that the injection of sweep fluid is performed independently from each other with the respective use of condensable gas and non-condensable gas. In a preferred embodiment, steam as the condensable gas is being injected via cavity <NUM>.

The plurality of sweep fluid injectors <NUM> may be, for example, each provided in the form of a separate sweep fluid injection lance. Such sweep fluid injection lances may be, for example, arranged around the polymer waste feed lance <NUM>. In such cases, a protective tube covering at least a part of the plurality of injection lances and at least a part of the polymer waste feed lance <NUM> may be further provided. As a consequence, various sweep fluids <NUM> may be guided through at least a part of the protective tube, but separately from the polymer waste feed. The protective tube as well as the polymer waste feed lance <NUM> and the plurality of injection lances arranged within the protective tube are stationary, i.e. not configured to rotate. Openings may be further instead or in addition provided through the front end <NUM> of the hollow chamber <NUM> for guiding at least one sweep fluid <NUM> into the first space <NUM>, for instance. The at least one sweep fluid injector <NUM> may be comprised by the polymer waste feed lance <NUM> or independent from the polymer waste feed lance <NUM>.

A pressure gradient between the first space <NUM> and the second space <NUM> is generated so that a fluid flow, particularly a gas flow, is formed in a direction from the first space <NUM> to the second space <NUM>, particularly towards a gas outlet <NUM>. In other words, a sweep fluid is used to enhance the flow from the first space <NUM> to the second space <NUM>. The pressure gradient further enhances the flow downstream towards an aftertreatment section (not shown). Injecting the sweep fluid <NUM> into the first space <NUM> causes the pressure in the first space <NUM> to increase so that the pressure in the first space <NUM> is greater than the pressure in the second space <NUM>. The pressure gradient may be, for example, in the range between <NUM> and <NUM> kPa, for example in the range between <NUM> and <NUM> kPa. A mass flow of the sweep fluid through the at least one sweep fluid injector <NUM> and/or a flow velocity may be adjustable in order to vary the pressure gradient. The pressure within the first space <NUM> and within the second space <NUM> can be monitored utilizing pressure sensors, respectively.

The sweep fluid <NUM> may be, for example, at least one of a condensable gas, steam, water, a non-condensable gas, nitrogen, a hydrocarbon, or diesel. As described above, also combinations of aforementioned sweep fluids <NUM> may be simultaneously injected into the first space <NUM>. Water may be, for example, sprayed via at least one nozzle comprised by the at least one sweep fluid injector <NUM> into the first space <NUM> or directly on a heated inner surface of the wall of the hollow chamber <NUM> in the first space <NUM>, thus causing the water spray to instantly vaporize and to generate steam in-situ inside the reactor, thus eliminating the need for a separate steam generating unit. The sweep fluid is then allowed to flow from the first space <NUM> into the second space <NUM>, for example via opening <NUM>. The fluid flow from the first space <NUM> into the second space <NUM> avoids a blowback of the gas <NUM> from at least partially pyrolyzed polymer waste. Use of a condensable gas, steam or water as a sweep fluid <NUM> is beneficial for aftertreatment purposes, when the sweep fluid <NUM> has to be separated from the product <NUM> at a later stage.

Additionally, the system comprises a gas outlet <NUM> arranged downstream of the at least one polymer waste feed outlet <NUM> for collecting a product <NUM> comprising the at least one sweep fluid <NUM> and a gas <NUM> from at least partially pyrolyzed polymer waste.

According to certain embodiments, a compressor (not shown) may be optionally provided downstream of the gas outlet <NUM> for improving or assisting the flow of the product <NUM>. The compressor may be also useful to keep the pressure within the first space <NUM> at a specific pressure, for example at atmospheric pressure, and to provide a pressure lower than the specific pressure within the second space <NUM>. In other words, the pressure within the first space <NUM> and the second space <NUM> may be adjusted by injecting the sweep fluid <NUM> into the first zone <NUM> and utilizing the compressor. The compressor is capable of controlling the pressure in an area where the gas outlet <NUM> is located. The injection of sweep fluid <NUM> ensures that no air is entering the system <NUM> and is also used to ensure that a backflow is avoided and to reduce any possible disturbance in the gas flow. Since the system <NUM> may, for example, operate under slight vacuum, it is prone to having an air leak into the system <NUM>. This could lead to combustion of hydrocarbons and result in fire and/or explosion. The combination of the compressor and the injection of sweep fluid <NUM> works as a system to provide guidance of pyrolysis gas towards the outlet <NUM>. In case that the normal vacuum condition is lost, injection of sweep fluid <NUM> can prevent hydrocarbons from leaking out of the system <NUM>.

Typically, a reduced pressure is provided at the location of the at least one gas outlet <NUM> to create a vacuum in order to remove the at least one sweep fluid <NUM> and the gas <NUM> from at least partially pyrolyzed polymer waste from the respective spaces <NUM>, <NUM>.

In <FIG> a schematic view of a heating system <NUM> of a system <NUM> in accordance with at least some embodiments of the present invention is illustrated. The hollow chamber <NUM> of <FIG> is arranged within a housing <NUM>. The heating system <NUM> has a first heating space <NUM> configured to receive a first heating gas having a first temperature T<NUM>. The first heating gas may be guided into the first heating space <NUM> via at least one first heating gas inlet <NUM> and guided out of the first heating space <NUM> via at least one first heating gas outlet <NUM>. Further, the heating system <NUM> has a second heating space <NUM> configured to receive a second heating gas having a second temperature T<NUM>. The second heating gas may be guided into the second heating space <NUM> via at least one second heating gas inlet <NUM> and guided out of the second heating space <NUM> via at least one second heating gas outlet <NUM>. As can be seen, the first heating space <NUM> is aligned with or arranged adjacent to the first space <NUM> and the second heating space <NUM> is aligned with or arranged adjacent to the second space <NUM>. The first heating space <NUM> may be in the form of a first heating chamber having a ring-like cross-section, for instance. The second heating space <NUM> may be in the form of a second heating chamber having a ring-like cross-section, for instance. The first heating gas and the second heating gas may be identical or different from each other. As a consequence, the first space <NUM> and the second space <NUM> can be individually heated by heating the wall <NUM> of the rotatable hollow chamber <NUM>. The temperature of the wall <NUM> of the rotatable chamber <NUM> can be adjusted by varying the first temperature T<NUM> of the first heating gas and/or the second temperature T<NUM> of the second heating gas. The wall temperature of the hollow chamber <NUM> may be, for example, in the first space <NUM> and in the second space <NUM> in a range between <NUM> and <NUM>. The temperature within the first space <NUM> and the second space <NUM> may be identical or different from each other. For example, the temperature within the first space <NUM> may be <NUM> and the second space <NUM> may be <NUM>.

In <FIG> a schematic view of another heating system <NUM> in accordance with at least some embodiments of the present invention is illustrated. As can be seen, the heating system <NUM> is configured to only heat the second space <NUM>. In such a configuration, it is not possible to spray water into the first space <NUM> as a sweep fluid. However, any sweep fluid in gaseous form may be injected into the first space <NUM>. For example, steam generated by a steam generator may be injected into the first space <NUM> via the at least one injector.

In <FIG> a schematic view of a detail of a heating system <NUM> in accordance with at least some embodiments of the present invention is illustrated. As can be seen, the second heating space <NUM> comprises a plurality of heating zones <NUM>, wherein each heating zone <NUM> is configured to receive a heating gas having a specific temperature TZ1,. The number of heating zones <NUM> can be any integer number greater than n=<NUM>. As a consequence, the heating zones <NUM> can be heated with different or identical temperatures Tzi,. , TZn, for instance. the temperatures TZ1,. , TZn are typically adjustable. For each heating zone <NUM> at least one heating gas inlet and at least one heating gas outlet are provided. Therefore, it is possible to heat each heating zone individually in order to generate a temperature gradient within areas of the second space <NUM>. In other words, different thermo-zones are thus formed between adjacent areas within the second space <NUM> due to the different heating zones <NUM>. For example, a temperature may be greater within an area of the second space <NUM> in a direction upstream of the direction of flow of the sweep fluid <NUM>. The concept of heating zones <NUM> may be incorporated into the heating system <NUM> as e.g. shown in <FIG> or <FIG>, i.e. either into an embodiment having a heating system <NUM> comprising a first heating space <NUM> and a second heating space <NUM> or into an embodiment having a heating system <NUM> comprising only the second heating space <NUM>.

In <FIG> a schematic view of a detail of a hollow chamber <NUM> of a system <NUM> in accordance with at least some embodiments of the present invention is illustrated. The system <NUM> comprises at least one structure <NUM> protruding in the first space <NUM> from an inner surface <NUM> of the rotatable hollow chamber <NUM> into the chamber <NUM>. The at least one structure <NUM> is a static or fixed structure. For example, a plurality of structures <NUM> in the form of plates may be arranged within the first space <NUM>. The plurality of plates is particularly beneficial for heat exchange within the first space <NUM>. Heat provided by the heating system <NUM> can be transferred into and distributed within the first space <NUM> of the hollow chamber <NUM> in order to quickly adjust or vary the temperature within the first space <NUM>. The plurality of the at least one structure <NUM> is typically, but not necessarily, made of the same material as the hollow chamber <NUM>. The material of the at least one structure has typically beneficial heat conducting properties.

In <FIG> a schematic view of a further detail of a rotatable hollow chamber <NUM> of a system <NUM> in accordance with at least some embodiments of the present invention is illustrated. The system <NUM> comprises at least one movable object <NUM> arranged within the first space <NUM> of the rotatable hollow chamber <NUM>. For example, the at least one movable object <NUM> may be a steel ball rolling within the first space <NUM> during rotation of the hollow chamber <NUM>. Instead or in addition, the movable object may be a chain, for instance. The at least one movable object <NUM> is typically, but not necessarily, made of the same material as the hollow chamber <NUM>. The material of the at least one movable object <NUM> has typically beneficial heat conducting properties. A further benefit of the at least one movable object <NUM> lies in that the movable object <NUM> scrapes the the inner surface <NUM> of the first space <NUM> during rotation of the hollow chamber <NUM> for cleaning purposes.

In <FIG> a schematic view of an even further detail of a hollow chamber <NUM> of a system <NUM> in accordance with at least some embodiments of the present invention is illustrated. According to the shown embodiment, the first space <NUM> and the second space <NUM> are rotated individually. In other words, the rotational speed of the first space <NUM> may be different from the rotational speed of the second space <NUM> as indicated by arrows rpm<NUM>, rpm<NUM>. The rotational speed of each of the first space <NUM> and the second space <NUM> may be, for example, in the range between <NUM> and <NUM> revolutions per minute (rpm), for example in the range between <NUM> and <NUM> rpm. However, both the first space <NUM> and the second space <NUM> or only the second space <NUM> may be heated as described above.

According to certain other embodiments, only the second space <NUM> is rotated and the first space <NUM> remains stationary. In such a configuration, there are no movable objects present within the first space <NUM> as described in connection with <FIG>. However, both the first space <NUM> and the second space <NUM> or only the second space <NUM> may be heated as described above.

In <FIG> a schematic view of a yet further detail of a hollow chamber <NUM> of a system <NUM> in accordance with at least some embodiments of the present invention is illustrated. The inner wall surface <NUM> within the second space <NUM> may be partially conical in order to prevent plastic waste material from being distributed in a direction towards the barrier <NUM>. The partially conical inner wall surface may be, for example, obtained by welding a hollow insert <NUM> having a conical inner surface to the barrier <NUM> and the inner wall of the hollow chamber <NUM> within the second space <NUM>.

In <FIG> a schematic view of a detail of a system <NUM> in accordance with at least some embodiments of the present invention is illustrated. The housing <NUM> comprises a cavity <NUM> or space into which a sweep fluid <NUM> in gaseous form can be guided. A plurality of borings <NUM> is further provided through the front end <NUM> of the hollow chamber <NUM>. Thus, the sweep fluid <NUM> in gaseous form can flow into the first space <NUM> through the borings <NUM>. The sweep fluid <NUM> in gaseous form can be guided into the first space <NUM> in systems <NUM> having a stationary first space <NUM> or in systems <NUM> having either individually or simultaneously rotating first and second spaces <NUM>, <NUM>. The cavity <NUM> as such is not being rotated. In other words, the detail shown in <FIG> represents a sweep fluid injector <NUM> for injecting a sweep fluid <NUM> into the first space <NUM>. One or more other sweep fluids <NUM> may be additionally injected into the first space <NUM>, for example by utilizing one or more sweep fluid lances as described above.

The operating principle of the shown embodiment differs from the operating principle of the embodiments shown in <FIG>. Particularly, at least one sweep fluid <NUM> is injected into both the first space <NUM> and the second space <NUM>, both comprised by a hollow chamber <NUM>.

The hollow chamber <NUM> is typically in the form of an elongated hollow cylinder. The term "elongated" means that a length of the hollow cylinder is substantially greater than a diameter of the hollow cylinder. For example, the length of the hollow cylinder may be <NUM> and the diameter of the hollow cylinder may be <NUM>. The hollow chamber <NUM> is typically made of a metal or metal alloy. At least the second space <NUM> is configured to be rotated around an axis of rotation A. The axis of rotation A is typically orientated horizontally or substantially horizontally. The term "axis orientated horizontally" means an axis that is orientated perpendicular to a gravity vector or perpendicular to the normal on the surface of the Earth. Similarly, the term "axis orientated substantially horizontally" means an axis that is tilted a few degrees, for example less than <NUM> degrees, from the axis that is orientated perpendicular to a gravity vector or perpendicular to the normal on the surface of the Earth. Only the second space <NUM> may be configured to rotate in the shown embodiment of <FIG>. According to other embodiments, both the first space <NUM> and the second space <NUM> are simultaneously rotated as disclosed in connection with <FIG> or both the first space <NUM> and the second space <NUM> are individually rotated as described in connection with <FIG>. The rotational speed of the first space <NUM> and/or the second space <NUM> may be, for example, in the range between <NUM> and <NUM> revolutions per minute (rpm), for example in the range between <NUM> and <NUM> rpm.

The system further comprises a heating system (not shown) as described above in connection with any one of <FIG>. i.e., both the first and the second spaces <NUM>, <NUM> are heated individually or only the second space <NUM> is heated. It may be further possible to heat heating zones of the second space <NUM> individually in order to generate a temperature gradient within areas of the second space <NUM>.

The system <NUM> yet further comprises a polymer waste feed lance <NUM> having at least one polymer waste feed outlet <NUM>. The polymer waste feed lance <NUM> is stationary, i.e. the polymer waste feed lance <NUM> is not configured to rotate and at least a part of the hollow chamber <NUM> is configured to rotate around the polymer waste feed lance <NUM>. The polymer waste feed lance <NUM> may be, for example, in the form of a hollow cylinder. A center axis of the polymer waste feed lance <NUM> is typically arranged or orientated coaxially with the axis of rotation A. The polymer waste feed lance <NUM> is typically made of metal or a metal alloy. The polymer waste feed lance <NUM> extends within the hollow chamber <NUM> at least through the first space <NUM>. The polymer waste feed lance <NUM> may additionally extend partially into the second space <NUM> as shown in <FIG>. The system <NUM> is configured to feed polymer waste <NUM> into the second space <NUM> via the at least one polymer waste feed outlet <NUM>. The polymer waste feed lance <NUM> is comprised by or coupled to a feeding system (not shown). The feeding system is typically an extrusion-type feeding system. The polymer waste <NUM> is (predominantly) pre-molten so that the feed is converted into a flowable form allowing travelling through the polymer waste feed lance <NUM>.

The polymer waste <NUM> material fed into the second space <NUM> via the at least one polymer waste feed outlet <NUM> of the polymer waste feed lance <NUM> falls on a heated inner surface <NUM> of the second space <NUM> due to gravity. The rotation of the second space <NUM> causes the polymer waste material <NUM> to distribute over at least a part of the inner surface <NUM> of the second space <NUM>. Distribution of the polymer waste material <NUM> over at least a part of the inner surface <NUM> of the second space <NUM> may be improved by tilting the rotatable hollow chamber <NUM> a few degrees, for example <NUM> degrees to <NUM> degrees from the horizontal axis. In such a configuration, the rotatable hollow chamber <NUM> is arranged substantially horizontally.

The high temperature wall of the hollow chamber <NUM> causes thermal decomposition of the polymer waste material <NUM> within the second space <NUM>, thus converting the polymer waste material <NUM> into a gas <NUM> from at least partially pyrolyzed polymer waste and a residue. The residue may comprise inorganics or inorganic contaminants, for instance. The shown hollow chamber <NUM> comprises a residue outlet <NUM> for the first space <NUM> and further another residue outlet <NUM> for the second space <NUM>.

The hollow chamber <NUM> further comprises a barrier <NUM> or seal between the first space <NUM> and the second space <NUM>. The barrier <NUM> or seal is configured to allow a fluid flow, particularly a gas flow, from the second space <NUM> to the first space <NUM>. An opening <NUM> is provided between the barrier <NUM> and the polymer waste feed lance <NUM>. The opening <NUM> may be permeable for the sweep fluid <NUM> and the gas <NUM> to flow into the direction from the second space <NUM> into the first space <NUM>, but impermeable into the opposite direction. The barrier <NUM> or seal may alternatively also comprise features allowing gas flow, i.e., a plurality of perforations, for instance. The barrier <NUM> is typically made of metal, a metal alloy or a high temperature resistant fabric.

The shown system <NUM> even further comprises a plurality of sweep fluid injectors <NUM> capable of injecting at least one sweep fluid <NUM> into the first space <NUM> and additionally into the second space <NUM>. In other words, the system <NUM> comprises, within a housing (not shown), a cavity <NUM> or space into which a sweep fluid <NUM> in gaseous form can be guided. The cavity <NUM>, as a part of the housing, is stationary. A plurality of borings <NUM> is further provided through the front end <NUM> of the hollow chamber <NUM>. Thus, a sweep fluid <NUM> in gaseous form can flow into the first space <NUM> through the borings <NUM>. The sweep fluid <NUM> in gaseous form can be guided into the first space <NUM> in systems <NUM> having a stationary first space <NUM> or in systems <NUM> having either individually or simultaneously rotating first and second spaces <NUM>, <NUM>. In other words, the cavity <NUM> shown in <FIG> represents a sweep fluid injector <NUM> for injecting a sweep fluid <NUM> into the first space <NUM>. One or more identical or other sweep fluid <NUM> may be additionally injected into the first space <NUM>, for example by utilizing one or more sweep fluid lances as described above. Further, an identical or another sweep fluid <NUM> is injected into the second space <NUM> as shown in <FIG>. Injection of a sweep fluid <NUM> into the second space <NUM> typically takes place through a rear end <NUM> of the hollow chamber <NUM>. For example, at least one further injection lance may be provided and/or another cavity or space into which a sweep fluid <NUM> in gaseous form can be guided may be provided, i.e. similar to the front end of the reactor.

Within the embodiment of <FIG>, the term "sweep fluid injector" means a specific unit for injecting the at least one sweep fluid <NUM> into the first space <NUM> or into the second space <NUM>. Such sweep fluid injector may, for example, comprise at least one sweep fluid injection lance extending into the first space <NUM> or into the second space <NUM>. Such sweep fluid injector may, for example, comprise a nozzle. Alternatively, the term "sweep fluid injector" may also mean a simple opening in the system <NUM> through which the at least one sweep fluid <NUM> can be guided into the first space <NUM>. The system <NUM> may also comprise a plurality of sweep fluid injectors <NUM>, wherein each sweep fluid injector <NUM> is capable of injecting a different sweep pluid <NUM> into the first space <NUM> or into the second space <NUM>. One sweep fluid injector <NUM> may be, for example, arranged to inject a condensable gas into the first space <NUM> or into the second space <NUM> and another sweep fluid injector <NUM> may be, for example, arranged to inject a non-condensable gas into the first space <NUM> or into the second space <NUM>. The plurality of sweep fluid injectors <NUM> may be, for example, each provided in the form of a separate sweep fluid injection lance. Such sweep fluid injection lances may be, for example, arranged around the polymer waste feed lance <NUM>. In such cases, a protective tube covering at least a part of the plurality of sweep fluid injection lances <NUM> and at least a part of the polymer waste feed lance <NUM> may be further provided. As a consequence, various sweep fluids <NUM> may be guided through at least a part of the protective tube, but separately from the polymer waste feed. The protective tube as well as the polymer waste feed lance <NUM> and the plurality of injection lances arranged within the protective tube are stationary, i.e. not configured to rotate. Openings <NUM> may be further instead or in addition provided through the front end <NUM> of the hollow chamber <NUM> for guiding at least one sweep fluid <NUM> into the first space <NUM> and/or through the rear end <NUM> of the hollow chamber <NUM> for guiding at least one sweep fluid <NUM> into the second space <NUM>, for instance. The at least one sweep fluid injector <NUM> may be comprised by the polymer waste feed lance <NUM> or independent from the lance <NUM>. A mass flow of the sweep fluid through the at least one sweep fluid injector <NUM> and/or a flow velocity may be adjustable. The pressure within the first space <NUM> and within the second space <NUM> can be monitored utilizing pressure sensors, respectively.

The sweep fluid <NUM> may be, for example, at least one of a condensable gas, steam, water, a non-condensable gas, nitrogen, a hydrocarbon, or diesel. As described above, also combinations of aforementioned sweep fluids <NUM> may be simultaneously injected into the first space <NUM> and into the second space <NUM>. Water may be, for example, sprayed via at least one nozzle comprised by the at least one sweep fluid injector <NUM> into the first space <NUM> or directly on a heated inner surface of the wall of the hollow chamber <NUM> in the first space <NUM>, thus causing the water spray to instantly vaporize and to generate steam in-situ inside the reactor, thus eliminating the need for a separate steam generating unit. The sweep fluid is then allowed to flow towards the gas outlet <NUM>. The fluid flow from the cavity <NUM> into the first space <NUM> avoids a blowback of the gas <NUM> from at least partially pyrolyzed polymer waste. Thus, the cavity <NUM> remains free of solid material particles carried towards the gas outlet <NUM>. Use of a condensable gas, steam or water as a sweep fluid <NUM> is beneficial for aftertreatment purposes, when the sweep fluid <NUM> has to be separated from the product <NUM> at a later stage.

Additionally, the system <NUM> comprises the gas outlet <NUM> comprised by the first space <NUM> for collecting a product <NUM> comprising the at least one sweep fluid <NUM> and a gas <NUM> from at least partially pyrolyzed polymer waste. By providing the gas outlet <NUM> in the first space <NUM>, i.e. away from the second space <NUM>, the content of solid material in the form of lightweight particles or dust carried by the product <NUM> can be decreased. A pressure gradient between the hollow chamber <NUM> and the at least one gas outlet <NUM> is typically in a range between <NUM> - <NUM> kPa, for example <NUM> - <NUM> kPa. Typically, a reduced pressure is provided at the location of the at least one gas outlet <NUM>, for example by utilizing a compressor, to create a vacuum in order to remove the at least one sweep fluid <NUM> and the gas <NUM> from at least partially pyrolyzed polymer waste from the respective spaces <NUM>, <NUM>.

The inner wall surface <NUM> within the second space <NUM> may be partially conical in order to prevent plastic waste material from being distributed in a direction towards the barrier <NUM>. The partially conical inner wall surface may be, for example, obtained by welding a hollow insert <NUM> having a conical inner surface to the barrier <NUM> and the inner wall of the hollow chamber <NUM> within the second space <NUM>.

In the description, numerous specific details are provided, such as examples of lengths, widths, shapes, etc., to provide a thorough understanding of embodiments of the invention.

Claim 1:
A system (<NUM>) comprising:
• a hollow chamber (<NUM>) comprising a first space (<NUM>) and a second space (<NUM>), wherein the second space (<NUM>) is rotatable or the first space (<NUM>) and the second space (<NUM>) are rotatable, wherein the hollow chamber (<NUM>) comprises a barrier (<NUM>) between the first space (<NUM>) and the second space (<NUM>),
• a heating system (<NUM>) configured to heat the second space (<NUM>) or to individually heat the first space (<NUM>) and the second space (<NUM>),a polymer waste feed lance (<NUM>) having at least one polymer waste feed outlet (<NUM>), wherein the polymer waste feed lance (<NUM>) extends within the hollow chamber (<NUM>) at least through the first space (<NUM>), wherein the system (<NUM>) is configured to feed polymer waste (<NUM>) only into the second space (<NUM>) via the at least one polymer waste feed outlet (<NUM>), and wherein an opening (<NUM>) is provided between the barrier (<NUM>) and the polymer waste feed lance (<NUM>), and
• at least one sweep fluid injector (<NUM>) capable of injecting at least one sweep fluid (<NUM>) into the first space (<NUM>) or into the first space (<NUM>) and into the second space (<NUM>) in order to form a fluid flow towards at least one gas outlet (<NUM>) for collecting a product (<NUM>) comprising the at least one sweep fluid and a gas (<NUM>) from at least partially pyrolyzed polymer waste.