WO2025104078A1

WO2025104078A1 - Separating screw conveyor for a pyrolisis system

Info

Publication number: WO2025104078A1
Application number: PCT/EP2024/082166
Authority: WO
Inventors: Niels Ole Cedergaard; Chresten Bugge SKJØDT
Original assignee: Makeen First
Current assignee: Makeen First
Priority date: 2023-11-13
Filing date: 2024-11-13
Publication date: 2025-05-22
Anticipated expiration: 2026-05-13

Abstract

The present invention relates to a separating screw conveyor (113) for a processing chamber of a pyrolysis plant. The screw conveyor (113) comprises an axle (A) with a peripheral surface (PS) extending along a longitudinal axis and having an inlet end (IE) and an outlet end (OE). The screw conveyor (113) further comprises a helical blade (HB), the helical blade extending helically around the peripheral surface (PS), along the longitudinal axis of the axle (A), the helical blade (HB) configured with a pitch to flight the mixed waste stream upon rotation of the axle (A), wherein the helical blade (HB) is arranged radially at a distance (d) from the peripheral surface (PS) of the axle (A) to enable for a portion of the mixed waste stream to move from between helical windings (W, W', W", Wn) of the helical blade (HB), near the peripheral surface (PS) of the axle (A), upon rotation of said axle (A). The distance (d) between the axle (A) and the helical blade (HB) enables for liquid portions of the mixed waste stream to flow in a direction opposite the flight direction, thus enabling the screw conveyor (113) to separate at least solid waste from liquid waste during the upcycling process.

Description

SEPARATING SCREW CONVEYOR FOR A PYROLISIS SYSTEM

FIELD OF THE INVENTION

The present invention relates to a separating screw conveyor, configured to, upon rotation, convey and separate portions of a material. The invention further relates systems and methods comprising the separating screw conveyor.

BACKGROUND OF THE INVENTION

In one or more stages of pyrolysis, wherein a waste material is processed or upcycled into e.g. oil and/or gas products, the waste material is heated and/or mixed in order for said processes to occur.

In order for a separation of the waste material to continuously occur, e.g. liquid and solids need to be separated during processing. Further, residual portions of the waste material, such as ash, black carbon, rock, glass, metal and calcium oxide needs to be separated from material which can be converted or upcycled into e.g. oil or gas products.

Hence, it is an object of the present invention to provide a separating screw conveyor for separating waste material from residual waste material during processing, to optimize the processing of the waste material, such as to increase output of upcycled material and discard solid waste which are not suitable for upcycling in a thermal processing plant.

It is a further object of the present invention to provide an alternative to the prior art.

SUMMARY OF THE INVENTION

Thus, the above described object and several other objects are intended to be obtained in a first aspect of the invention by providing a separating screw conveyor for a pyrolysis system adapted to upcycle a mixed waste stream, the screw conveyor comprising : -an axle with a peripheral surface extending along a longitudinal axis and comprising an inlet end and an outlet end,

-a helical blade, the helical blade extending helically around the peripheral surface, along the longitudinal axis of the axle, the helical blade configured with a pitch to flight the mixed waste stream upon rotation of the axle, wherein the helical blade is arranged radially at a distance (d) from the peripheral surface of the axle to enable for a portion of the mixed waste stream to move from between helical windings of the helical blade, near the peripheral surface of the axle.

The invention is particularly, but not exclusively, advantageous for obtaining an upcycled material from a mixed waste stream, such as plastic waste or mixed plastic waste. By separating liquid waste from solid waste within the mixed waste stream, the present invention enables for an increased output of upcycled material, thus providing an increased output of usable material or product from the mixed waste stream.

In the context of the present invention, pyrolysis is to be understood as a process of thermal decomposition of materials at elevated temperatures in an inert atmosphere. It is used to break down organic or synthetic materials into smaller molecules, producing e.g. volatile products and leaving char, a carbon-rich solid residue as a final waste product.

In the context of the present invention, upcycle is to be understood as the process of reusing waste materials to create a product of higher quality or value than the original. In particular, organic or synthetic waste, such as plastic waste may be processed into oil products, such as fuel oil.

In the context of the present invention, screw conveyor is to be understood as a mechanism that uses a rotating helical screw blade, called a flighting, usually within a tube, typically to move liquid or granular materials.

In the context of the present invention, mixed waste stream is to be understood as a waste product of e.g. organic or synthetic origin or a mix of both. In particular, a mixed waste stream may be understood as a mix of plastic waste with different mechanical or chemical properties.

In the context of the present invention, convey is to be understood transport of a mixed waste stream or a material from said mixed waste stream. In the context of the present invention, convey and flight may be used interchangeably, when relating to screw conveyors.

Within the context of the present invention the distance (d) between the axle and the helical blade is to be construed as a gap or gap area, wherein the gap enables for liquid to flow in a direction opposite to a flight direction.

It is further to be understood, that the flighting or conveying of the mixed waste stream is a result of rotation of the screw conveyor, wherein the axle is adapted to rotate upon the provision of a rotational force, and wherein the arrangement of the helical blade around the axle provides rotation between the interconnecting parts of said screw conveyor, i.e. the axle and the helical blade.

In the context of the present invention, it is to be understood, that pyrolysis plant and pyrolysis system may be used interchangeably.

It is further to be understood, that when processing plastic waste, temperature and viscosity may co-dependent or be linear in relationship.

It is further to be understood, that the blade height may be dependent on the diameter of the axle. In a preferred embodiment, the diameter of the axle is between 200 and 500 mm, more preferred between 300 and 400 mm, even more preferred between 350 and 390 mm, such as 370 mm.

It is to be understood that within the context of the present invention, pitch or pitch of flight is to be understood as a ratio between the diameter of the blade and the angle of the pitch, i.e. wherein a 1: 1 ratio determines that one rotation of the helical blade moves material in between adjacent winding of the helical blade, one winding further forwards; and a 1:5 pitch determines that five rotations of the helical blade moves material in between adjacent winding of the helical blade, one winding further forwards. In other words, pitch refers to the distance between adjacent screw flights. The flight is the helical screw blade that rotates and moves materials along the conveyor. The pitch of the flight is the distance between the tips of two adjacent flights, measured parallel to the axis of the screw conveyor.

In preferred embodiments, the pitch of the helical blade is between 1:0.5 and 1:20, more preferred between 1: 1 and 1: 10, even more preferred between 1: 1 and 1:5, such as 1:4.

It is to be understood, that the pitch of flight and height of the helical blade, may be based on initial mechanical properties of the mixed waste stream and/or a target temperature of said mixed waste stream.

It is further to be understood, that the axle may be a shaft, i.e. a hollow shaft.

In a preferred embodiment of the invention, the axle is positioned at an oblique angle relative to a horizontal axis, between the inlet end and the outlet end. This embodiment is particularly advantageous to ensure the flow of liquid waste from the mixed waste stream in a direction opposite the flight direction, i.e. wherein gravity and the distance between the axle and the windings of the helical blades enables the liquid to flow back/downwards, and wherein the flight direction is forward/upwards, relative to the flight direction, thus the solid waste being flighted forwards/ upwards.

In another preferred embodiment of the invention, the oblique angle is in the range from 5 to 35 degrees, such as 15 to 25 degrees, preferably approximately 20 degrees relative to a horizontal axis.

In yet another preferred embodiment of the invention, the outlet end is positioned vertically higher than the inlet end.

In an advantageous embodiment, the invention further comprises a plurality of radial connecting members which extend radially between the helical blade and the peripheral surface of the axle. It is to be understood, that in some embodiments, the radial connecting members may be integrated into the helical blade, i.e. as part of said blade. This embodiment is particularly advantageous for ensuring the structural integrity of the helical blade during flighting. In some embodiments, the axle extends along between 5 and 7 meters, such as 6 meters, thus requiring a rigid structure to avoid bending of said axle, during rotation.

In another advantageous embodiment of the invention, a pitch of flight of at least a portion of the helical blade is between 1:0.4 and 1:8 more preferably between 1:0.7 and 1:7 even more preferably between 1:0.8 and 1:6, and most preferably between 1:0.9 and 1:5, such as 1:4.

In yet another advantageous embodiment of the invention, a pitch of flight of the helical blades varies along the length axis of the axle. This embodiment is particularly advantageous for the continued separation of the mixed waste stream, as the viscosity of said mixed waste stream changes along the length of the axle, due to an increased amount of solid waste to liquid waste near an outlet end of said axle.

In a preferred embodiment of the invention, the pitch of flight varies between 1: 1 and 1:5 along the length axis of the axle, preferably as between 1: 1 and 1:4. It is to be understood, that the pitch of flight may be e.g. 1:2 at a section of the axle and 1:4 at another section of the axle. This embodiment is particularly advantageous for the continued separation of the mixed waste stream, as the viscosity of said mixed waste stream changes along the length of the axle, due to an increased amount of solid waste to liquid waste near an outlet end of said axle.

In another preferred embodiment of the invention, the pitch of flight reduces from the inlet end towards the outlet end. In other embodiments, the pitch of flight increases from the inlet end towards the outlet end. As the viscosity of the mixed waste stream changes, the pitch of flight may be varied, to ensure continued flight of said mixed waste stream.

In yet another preferred embodiment of the invention, a radial height (BH) of the helical blade is defined between an outer edge and an inner edge of said helical blade, and wherein said radial height is between 50 and 90 mm. In other embodiments, the radial height of the helical blade is between 50 and 200 mm, such as between 55 and 150 mm. In advantageous embodiments of the invention, the radial height of the helical blade is between 60 and 140 mm, such as between 65 and 100 mm, such as 70 mm.

In an advantageous embodiment of the invention, a ratio, R, of the radial height, BH, of the helical blade to distance, d, where d is defined as the distance of gap between the inner edge of the helical blade and the peripheral surface of the axle, is defined by R = BH/d, and R is between 0.5 and 2. In other advantageous embodiments, the ratio R, is between 0.1 and 0.5, such as approximately 0.2.

In another advantageous embodiment of the invention, gap area between the inner edge of the helical blade and the peripheral surface of the axle is between 0.1 and 2 of an area of the helical blade, such as approximately 0.2. This embodiment is particularly advantageous for ensuring a free flow of liquid waste in a direction opposite to a direction of flight, from the mixed waste stream.

It is to be understood, that windings of the helical blade are not two-dimensional, and neither is the gap area, due to the helical shape of the separating screw conveyor, but when gemetrically/mathematically flattening the surfaces, one winding of the helical blade, and the gap area represents two-dimensional areas. Thus, a ratio can be calculated. As an example, wherein the ratio is 0.2: If the area of a winding of the helical blade is 10 cm², the gap area would be 2 cm².

It is further to be understood, that the helical windings are manufactured from a flat material, such as a steel sheet and afterwards cut and twisted into a helix. Thus, the opposite can be performed to measure the ratio between area of windings and gap area.

In yet another advantageous embodiment of the invention, at least one elongate member extends between at least two adjacent helical windings of the helical blade at or near an outer edge of said blade. In some embodiments, at least two elongate members extends between at least two adjacent helical windings of the helical blade at or near an outer edge of said blade, said at least two elongate members arranged in parallel. This embodiment is particularly advantageous for providing structural stiffness or rigidity of the helical blade windings. Further, said elongate members may be advantageous to ensure that mixed waste stream at an outer periphery is scooped or scraped further on in the direction of flight. In yet another advantageous embodiment, at least one elongate member extends between at least two adjacent helical windings of the helical blade, the at least one elongate member positioned radially centered between the edge of the helical blade and the peripheral surface of the axle. This embodiment is particularly advantageous for providing structural stiffness or rigidity to the helical blade windings positioned at a distance from the peripheral surface of the axle, without scraping and hence disturbing solids which have settled, thus ensuring the continuous conveyance/transport of said solids towards the outlet.

In a preferred embodiment, the axle comprises at least a first and second section, the first section comprising the helical blade according to the first aspect, arranged at a distance from the peripheral surface of the axle, the second section comprising a second helical blade, the second helical blade extending from the peripheral surface of the axle, preventing the mixed waste stream from moving between helical windings of the second helical blade. This embodiment is particularly advantageous for ensuring, that solids are conveyed towards the outlet, and wherein the helical blade arranged at a distance provices for a section wherein liquids can be separated from said solids.

In another preferred embodiment, the axle further comprising a third section, the third section comprising a third helical blade, the third helical blade extending from the peripheral surface of the axle, preventing the mixed waste stream to move from between helical windings of the third helical blade. This embodiment is particularly advantageous for ensuring, that solids are conveyed towards the outlet, and wherein the helical blade arranged at a distance provices for a section wherein liquids can be separated from said solids.

In a most preferred embodiment, the first section of the axle is arranged in between the second and the third section, the helical blade arranged at a distance from the peripheral surface of the axle arranged in between the second helical blade and the third helical blade. This embodiment is particularly advantageous for ensuring, that solids are conveyed towards the outlet, and wherein the helical blade arranged at a distance provices for a section wherein liquids can be separated from said solids. In particular this embodiment is advantageous in a processing chamber, such as a reactor, filled to a specific level with a mix of liquids and solids, and wherein a liquid level of the reactor intersects with the first section of the axle.

It is to be understood, that a portion of the solid waste is heavier than a portion of the liquids and thus settles at the bottom of the processing chamber. The inventors have realized, that providing a section of the axle with a helical blade extending from the peripheral surface of the axle at or near a bottom of the processing chamber, below the fill level/liquid level, ensures the conveyance of settled solid waste towards the outlet. It is further to be understood, that the helical blade arranged at a distance from the peripheral surface of the axle ensures that liquids conveyed towards the outlet, is allowed flow back towards the processing chamber/reactor, thus concentrating liquid and continuously removing solids from said processing chamber/reactor.

In a second aspect, the invention relates to a processing chamber, the processing chamber adapted to be a section in a multi-section pyrolysis system for upcycling mixed waste streams, the processing chamber comprising:

-at least a first screw conveyor according to the first aspect of the invention,

-an inlet and an outlet, wherein the screw conveyor is adapted to flight at least a portion of the mixed waste stream through the chamber, from the inlet towards the outlet, the outlet connected to an associated section of the multi-section pyrolysis system and further adapted to enable a portion of the mixed waste stream to flow towards the inlet, such as to allow liquid residue to flow towards the inlet, opposite a direction of flight.

It is to be understood, that a multi-section pyrolysis system is to be understood as a pyrolysis plant, such as the plant described in FIG. 1, and wherein the processing chamber according to the second aspect is a chamber of said plant, in particular the reactor of the pyrolysis plant. This aspect of the invention is particularly advantageous for ensuring proper separation of liquid waste from solid waste within a processing chamber of a pyrolysis plant.

It is further to be understood, that the screw conveyor enables for a portion of the mixed waste stream, such as liquid, to flow opposite the flight direction due to the distance between the helical blade and the peripheral surface of the axle, i.e. wherein heavy/settling portions such as black carbon are conveyed/flighted while liquid may overflow in between adjacent windings and thus travel towards the inlet and the outlet end.

In a preferred embodiment, the invention further comprises one or more heating elements arranged in or on said chamber, the heating elements adapted to heat the mixed waste stream. It is to be understood, that a pyrolysis plant processes the mixed waste stream by utilizing heat to break down the composition of said mixed waste stream.

In another preferred embodiment, the invention further comprises one or more sensors adapted to measure one or more of temperature, texture, viscosity or porosity of the mixed waste stream. It is to be understood, that sensors may be adapted to control one or more of heat applied to the screw conveyor from associated heating means, such as induction heaters or other suitable heating devices, to control RPM of the axle and thus the screw conveyor; or to control a variable pitch of the helical blades. This embodiment may be particularly advantageous to continuously adapt the uniform mixing and heating of the mixed waste stream and to ensure sufficient separation of the mixed waste stream into solid waste and liquid waste.

In yet another preferred embodiment, the processing chamber is a pyrolysis reactor adapted to upcycle at least a portion of the mixed waste stream during heating, such as to convert a portion of the mixed waste stream into an oil product. Thus, it is to be understood, that in advantageous embodiments of the invention, the processing chamber is the reactor, as shown in FIG. 1, referenced as 103. In a preferred embodiment of the invention,

In an advantageous embodiment, the invention further comprises a motor adapted to rotate at least the axle or shaft of the screw conveyor. In some embodiments, the motor is adapted to vary the revolutions per minute (RPM), based on e.g. sensor measurements, such as temperature or viscosity or other relevant measurements. In some embodiments, the motor is further adapted to measure torque as an indication of viscosity of the mixed waste stream being flighted within the processing chamber. In some embodiments of the invention, the separating screw conveyor is adapted to operate at between 0.1 and 10 RPM. In preferred embodiments of the invention, the separating screw conveyor is adapted to operate at between 0.3 and 8 RPM. In a more preferred embodiment of the invention, the separating screw conveyor is adapted to operate at between 0.6 and 5 RPM. In an even more preferred embodiment of the invention, the separating screw conveyor is adapted to operate at between 0.8 and 3 RPM. In an advantageous embodiment of the invention, the separating screw conveyor is adapted to operate at between 0.8 and 1.5 RPM, such as approximately at 1 RPM.

In another advantageous embodiment, the invention further comprises a second screw conveyor according to the first aspect of the invention, the second screw conveyor arranged within the processing chamber substantially parallel to the first screw conveyor.

In yet another embodiment of the invention, the first and second screw conveyors are adapted to operate in different phases of flight.

In a yet another preferred embodiment of the invention, the first and second screw conveyors are adapted to operate at opposite phases of flight.

These embodiments are particularly advantageous for ensuring further separation of liquid waste from solid waste, while ensuring continuous flight of solid waste towards a discard section of the pyrolysis plant. In yet another advantageous embodiment of the invention, the processing chamber has a length of between 20 and 2 meters, preferably between 15 and 3 meters, more preferably between 10 and 4 meters, even more preferably between 8 and 5 meters. In an advantageous embodiment of the invention, the processing chamber is approximately 6 meters in length, measured parallel to a longitudinal axis of the axle of the separating screw conveyor.

In a third aspect, the invention relates to a pyrolysis system for upcycling mixed waste streams, the system comprising the screw conveyor according to the first aspect of the invention or the processing chamber according to the second aspect of the invention, the system further comprising:

-a carbon container, and

-a de-gasser, wherein at least the carbon container and the de-gasser are directly or indirectly fluidically connected.

This aspect is particularly advantageous for providing a pyrolysis plant with a high output of upcycled material from the mixed waste stream.

In a preferred embodiment of the invention, the de-gasser is directly or indirectly fluidically connected to the processing chamber.

In another preferred embodiment of the invention, the de-gasser is arranged substantially horizontally and the processing chamber is arranged substantially oblique or inclined, relative to said de-gasser. This embodiment is advantageous for utilizing gravity as a means of separating liquid waste from solid waste within the reactor of the pyrolysis plant or system.

In a fourth aspect, the invention relates to a method of separating a stream of mixed waste material comprising waste solids and waste liquids in a pyrolysis system, the method comprising:

-providing a screw conveyor according to the first aspect of the invention or a processing chamber according to the second aspect of the invention, -feeding the mixed waste material at the inlet or inlet end, -separating the waste liquids from the waste solids by rotating the axle, and

-conveying at least a portion of the waste solids to an associated section of the pyrolysis system, when the mixed waste stream is processed in said pyrolysis system.

In a preferred embodiment of the invention, the mixed waste material comprises up to 25 % waste solids.

In another preferred embodiment of the invention, at least 90% of the waste solids are conveyed to an associated section of the pyrolysis system. In an even more preferred embodiment of the invention, at least 95% of the waste solids are conveyed to an associated section of the pyrolysis system. In a most preferred embodiment of the invention, at least 99% of the waste solids are conveyed to an associated section of the pyrolysis system.

In yet another preferred embodiment the method further compries the following steps:

-filling the processing chamber with a mix of solid and liquid waste material to a specific fill level,

-operating the screw conveyor, wherein the specific fill level intersects with the first section of the axle and the second section of the axle is above or below the fill level. This embodiment is particularly advantageous for ensuring that liquid waste is allowed to return to the processing chamber/reactor, while settled solids are continuously conveyed towards the outlet.

In a fifth aspect, the invention relates to the use of a screw conveyor according to the first aspect of the invention, for the upcycling of a mixed waste stream into an upcycled material or product, such as an oil or gas product, preferably such as a fuel oil or fuel gas.

In a sixth aspect, the invention relates to a method of manufacturing an upcycled material, such as oil, from a mixed waste stream, the method comprising the following steps: -providing a pyrolysis system according to the third aspect of the invention, -providing a mixed waste stream,

-processing the mixed waste stream through the pyrolysis system, and -providing oil from the mixed waste stream, wherein at least a portion of the mixed waste stream is processed into ash or black carbon.

This aspect of the invention is particularly, but not exclusively, advantageous in that the method may provide a method of increasing output of oil or gas from the mixed waste stream, relative to the known prior art.

The first, second, third, fourth, fifth and sixth aspect of the present invention may each be combined with any of the other aspects. These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

BRIEF DESCRIPTION OF THE FIGURES

The separating screw conveyor according to the invention will now be described in more detail with regard to the accompanying figures. The figures show one way of implementing the present invention and is not to be construed as being limiting to other possible embodiments falling within the scope of the attached claim set.

FIG. 1 is a schematic view of an embodiment of a pyrolysis plant for recycling of plastics making use of the present invention;

FIG. 2 shows a trimetric view of a portion of the separating screw conveyor, according an embodiment of the invention;

FIG. 3A and FIG. 3B shows a frontal view of the helical blade HB of the separating screw conveyor;

FIG. 4 shows a frontal view of the helical blade HB of the separating screw conveyor;

FIG. 5 is a trimetric view of a section of a reactor 103, according to an embodiment of the invention;

FIG. 6 is a flow-chart of a method according to the invention;

FIG. 7 shows a trimetric view of a separating screw conveyor according to a preferred embodiment of the invention; FIG. 8 shows a side view of the separating screw conveyor 113, according to a preferred embodiment of the invention;

FIG. 9A and FIG. 9B shows a frontal view of the helical blades HB, HB', HB" of the separating screw conveyor 113 according to a preferred embodiment of the invention.

DETAILED DESCRIPTION OF AN EMBODIMENT

In FIG. 1, a schematic diagram of a pyrolysis plant for recycling of plastics making use of the present invention is shown.

In this pyrolysis plant, a residual polymer product (also referred to as waste plastic or mixed waste stream) is fed to a densifier 101 wherein the product is compressed, preferably at a ratio of 2-3.5, by screw conveyors 111. A vapour outlet 121 is provided to release water vapour released from the residual polymer products being compressed. By removing the water vapour, vapour explosions in the system may be avoided as well as it is avoided that the pyrolysis oil produced is being oxidized. The compressed residual polymer product is forwarded through a de-gas feeder 101a, where a pH regulating additive, preferably Calcium Oxide (CaO), is added through an inlet 132 at the entry region in the de-gas feeder 101a. The Calcium Oxide is then mixed with the residual polymer product quickly in the de-gas feeder 101a. During the travel through the de-gas feeder the residual polymer product is heated in a heatable pipe 131. In a first section 102a the product is heated to 180-220°C and in a second section 102b, 102c further heated to approx. 200-280°C. The residual polymer product is then fed into the de-gasser 102. In the de-gasser 102 the residual polymer product is moved substantially horizontally by the two-way screw conveyor 112, through three heating zones 102a, 102b and 102c. In the de-gasser 102, the zones heat the media, i.e. the residual polymer product, up to max. 240°C in the first zone 102a and heat the media up to max. 260°C in the second zone 102b and up to max. 280°C in the third zone 102c. A gas outlet 122b is provided above at least the zones 102b and 102c as shown in the FIG. 1. Inside the de-gasser 102 the pressure is within the range of 0.1 to 1 bar, such as 0.2-0.45 bar. The residual polymer product, also referred to as the media or plastic pulp is then transferred to the pyrolysis reactor 103 through a pipe conveyor 150 containing a transport screw conveyor. The de-gasser, which is horizontally oriented, and the pyrolysis reactor, which is tilted upwards, are connected so there is a fluid communication between the outlet 122a at the bottom of the de-gasser 102 and the inlet 123a at the lowermost region of the tilted pyrolysis reactor 103. As indicated in FIG. 1 the liquid level 191 is about the same as in the de-gasser 102.

The pyrolysis reactor 103 preferably comprises two separating screw conveyors 113, preferably arranged in parallel hence only one is shown in FIG. 1. The separating screw conveyors 113 are conveying the residual polymer product and mixing the product whilst lifting upwards and out of the liquid level towards a black carbon outlet 123b at the top of the reactor 103. The pyrolysis liquid in the reactor 103 is heated by a heater, such as an electrical heater, for heating the residual polymer product to a temperature of up to max. 500 °C to generate pyrolysis vapour. The heating can be arranged in heating zones. The pressure inside the pyrolysis reactor 103 is similar to the pressure of the de-gasser, i.e. 0.1 to 1 bar, such as 0.2-0.45 bar.

The pyrolysis vapour is released from the reactor 103 via a reactor vapour outlet 123c. The reactor vapour outlet 123c is away from the dry portion of the reactor to avoid dripping of any condensed vapour onto the dried black carbon. Towards the end of the separating screw conveyors 113 substantially all of the residual polymer product will have been decomposed and a solid fraction comprising black carbon residue will leave the process in the end of the reactor 103. The black carbon is transported out of the reactor 103 via the black carbon outlet 123b placed in the reactor to receive the black carbon. At the outlet 123b a black carbon screw conveyor 133 may be arranged in extension of the black carbon outlet 123b for transferring the black carbon to a container. Advantageously, also a gas lock valve (not shown) may be provided to ensure that no gases escape through the black carbon outlet 123b.

The pyrolysis vapour released from the reactor 103 via a reactor vapour outlet 123c is fed into the oil reactor 104. The oil reactor 104 functions as a vapourliquid separator. The reactor vapour outlet pipe 123c is positioned in the oil reactor 104 such that the pipe exit 123d is below the liquid level 104d in the oil reactor 104. The oil reactor 104 may be heated in three zones 104a, 104b and 104c as indicated in FIG. 1. In each zone the pyrolysis vapour product is heated to max. 450 °C. The pyrolysis vapour is released into the oil reactor 104 below the liquid level as shown in the FIG. 1. If the product liquefies in the oil reactor 104 and fall to the bottom thereon, this heavy oil and any solid particles is returned to the pyrolysis reactor 103 via the pipe 124c for further decomposition in the pyrolysis reactor 103.

In the top of the oil reactor 104 two outlets 124a, 124b are provided for transferring vapour components to the two reflux condensers 105a, 105b. All the pyrolysis vapour enters at the bottom of each of the reflux condensers 105 and exits at the top of the reflux condensers 105a, 105b with a temperature of max. 260°C. From the top of the reflux condensers 105a, 105b, the pyrolysis vapour is led to the raw pyrolysis oil (RPO) condensers 106a and 106b, where the vapour is condensed to heavy products (Raw Pyrolysis Oil or RPO) with an outlet temperature of approx. 150-180°C. Furthermore, pyrolysis vapours are transferred to the Nafta Pyrolysis Oil condenser 107, in which the vapours are condensed and chilled and exits as a light product at a temperature of 10-35°C.

The transfer of the product from the de-gasser 102 through the pipe conveyor 150 and the transfer of the black carbon in carbon screw conveyor 133 from the reactor 103 are both shown schematically to be in line with the de-gasser 102 and the reactor 103, respectively. However, it is found of preference to provide the pipe conveyor 150 at an angle to the de-gasser and also to provide the carbon screw conveyor 133 at an angle to the reactor 103.

FIG. 2 shows a trimetric view of a portion of the separating screw conveyor 113, according an embodiment of the invention.

In FIG. 2, a section of a separating screw conveyor 113 is shown, at an oblique or inclined angle, relative to a horizontal axis. Through out this application, screw conveyor and separating screw conveyor 113, may be used interchangeably, at least when the screw conveyor is positioned within a reactor 103 as shown in FIG. 1. The separating screw conveyor 113 comprises an axle A, the axle A extending along a longitudinal axis and having an inlet end IE or bottom portion BP and an outlet end OE or top portion TP. Around a peripheral surface (not visible) of the axle A, a helical blade HB extends helically around the peripheral surface, along the longitudinal axis of the axle A, the helical blade HB configured with a flight to convey a mixed waste stream (not shown) upon rotation of the axle A. The helical blade HB is arranged radially at a distance (d) (visible in FIG. 3A and FIG. 3B), from the peripheral surface of the axle A to enable for a portion of the mixed waste stream (not shown) to move from between helical windings W, W', W'" to Wn, of the helical blade HB, near the peripheral surface of the axle A. From FIG. 2, it can further be seen, that elongate members EM, EM' extends between adjacent helical windings W to Wn of the helical blade HB near an outer edge RP of the helical blade windings HB, W, W', W", Wn. The elongate members EM substantially aligns to a radial periphery of the helical blade HB, thus adapted to scrape along or near an inside wall of a reactor (See FIG.l). The elongate members EM' are recessed from the radial periphery of the helical blade HB. The function of the protruding elongate members EM, are two-fold by a) to scrape residue from a bottom portion BP of the reactor 103, to enable for the separating screw conveyor 113 to convey said residue along, and b) to stiffen the helical blade HB along a longitudinal axis, whereas the recessed elongate members EM' are mainly adapted to stiffen the helical blade HB at a top portion TP of the reactor 103. See FIG. 3A and FIG. 3B for further details related to the elongate members EM, EM'.

FIG. 3A and FIG. 3B shows a frontal view of the helical blade HB of the separating screw conveyor 113.

It should be mentioned, that FIG. 3A and FIG. 3B are identical, apart from the configuration of the elongate members EM, EM'.

In FIG. 3A, the separating screw conveyor 113 comprises an axle A at the centre. Around a peripheral surface PS of the axle A, a helical blade HB extends around the peripheral surface PS. The helical blade HB is arranged radially at a distance d, from the peripheral surface PS of the axle A to enable for a portion of the mixed waste stream (not shown) to move from between helical windings (See W, W', W'" to Wn of FIG.2), of the helical blade HB, near the peripheral surface PS of the axle A. From FIG. 3A, it can further be seen, that elongate members EM, is positioned at an outer edge RP of the helical blade HB. The elongate members EM substantially aligns to a radial periphery RP of the helical blade HB, thus adapted to scrape along or near an inside wall of a reactor (See FIG. l). The function of the protruding elongate members EM, are two-fold by a) to scrape residue from a bottom portion of the reactor 103 (see FIG. 1), to enable for the separating screw conveyor 113 to convey said residue along, and b) to stiffen the helical blade HB along a longitudinal axis.

In FIG. 3B, the elongate members EM' are recessed from the radial periphery RP of the helical blade HB. The function of the recessed elongate members EM' are mainly adapted to stiffen the helical blade HB along a longitudinal axis.

In FIG. 3A and FIG. 3B, four elongate members EM, EM' are positioned on the helical blade HB. It is to be understood, at more or fewer elongate members EM, EM' may be adapted to the helical blade HB, depending on the geometry of the helical blade HB.

FIG. 4 shows a frontal view of the helical blade HB of the separating screw conveyor 113.

It should be noted, that FIG. 4 is similar to that of FIG. 3B, but has different annotation to show further details than those of FIG. 3B.

In FIG. 4 the separating screw conveyor 113 comprises an axle A at the centre. Around a peripheral surface PS of the axle A, a helical blade HB extends around the peripheral surface PS. The helical blade HB is arranged radially at a distance d, from the peripheral surface PS of the axle A. The helical blade HB is defined by a blade area BA, which consists of the area not defined by the gap area GA, and the axle A, wherein the gap area is defined by the area within the inner edge INE of the helical blade HB. In other words, the blade area BA, is defined between the radial periphery RP of the helical blade HB and the peripheral surface PS of the axle A, subtracted by the gap area GA. Further, a radial height BH of the helical blade HB is defined between an outer edge RP and an inner edge IE of said helical blade HB.

FIG. 5 is a trimetric view of a section of a reactor 103, according to an embodiment of the invention. In particular, the section shown relates to the outlet end OE or top end TE of the separating screw conveyor 113, according to the invention. In FIG. 5, two separating screw conveyors 113, 113' is shown, arranged in parallel.

FIG. 6 is a flow-chart of a method of separating a stream of mixed waste material comprising waste solids and waste liquids in a pyrolysis system according to the invention, the method comprising the following steps:

51 providing a screw conveyor according to the first aspect of the invention or a processing chamber according to the second aspect of the invention,

52 feeding the mixed waste material at the inlet or inlet end,

53 separating the waste liquids from the waste solids by rotating the axle, and

54 conveying at least a portion of the waste solids to an associated section of the pyrolysis system, when the mixed waste stream is processed in said pyrolysis system.

In an alternative embodiment, FIG. 6 is a flow-chart of a method of manufacturing an upcycled material, such as oil, from a mixed waste stream, the method comprising the following steps:

51 providing a pyrolysis system according to the third aspect of the invention,

52 providing a mixed waste stream,

53 processing the mixed waste stream through the pyrolysis system, and

54 providing oil from the mixed waste stream, wherein at least a portion of the mixed waste stream is processed into ash or black carbon.

FIG. 7 shows a trimetric image of a separating screw conveyor 113 according to a preferred embodiment of the invention. In FIG. 7, the separating screw conveyor 113 is arranged at an angle in a reactor 103 (see FIG. 1), adapted to transport solids, such as black carbon, from the reactor to an outlet for disposal. Within the reactor 103, a liquid level LL is present. It is to be understood, that the liquid level LL within the reactor may vary slightly. The liquid level is more clearly illustrated in FIG. 8. The screw conveyor is arranged with three sections, and wherein the first section comprises helical blades HB arranged at a distance from the axle A. A second and third section comprises helical blades HB', HB" which does not have cut-outs nor are arranged from a distance from the axle A, thus preventing substantial backflow of solids to the reactor. Thus, it is to be understood, that a section different than the first section is below or near the liquid level, adapted to scoop and convey settled solids from a bottom of the reactor 103 to the outlet, and wherein liquids trapped within or around the solids may flow back towards the reactor 103, when reaching the second section of the screw conveyor 113. FIG. 7 further shows four elongate members EM" arranged between the outer edge RP of the helical blades HB, HB', HB" and the axle, adapted to stiffen the separating screw conveyor 113 along its length.

FIG. 8 shows a side view of the separating screw conveyor 113, according to a preferred embodiment of the invention. In FIG. 8, the separating screw conveyor 113 is arranged at an angle in a reactor 103 (see FIG. 1), adapted to transport solids, such as black carbon, from the reactor to an outlet for disposal. Within the reactor 103, a liquid level LL is clearly visualized. See FIG. 7 for further details with respect to the separating screw conveyor 113.

It should be mentioned, that FIG. 9A and FIG. 9B are identical, apart from the cut-outs of the helical blades HB, HB', HB".

In FIG. 9A, the separating screw conveyor 113 comprises an axle A at the centre. Around a peripheral surface PS of the axle A, a helical blade HB extends around the peripheral surface PS. The helical blade HB is arranged radially at a distance d, from the peripheral surface PS of the axle A to enable for a portion of the mixed waste stream (not shown) to move from between helical windings (See W, W', W'" to Wn of FIG.2), of the helical blade HB, near the peripheral surface PS of the axle A. From FIG. 9A, it can further be seen, that elongate members EM", is positioned substantially centered between an outer edge RP of the helical blade HB and the peripheral surface PS of the axle A. The function of the protruding elongate members EM, are two-fold by a) stiffening the separating screw conveyor 113 along a longitudinal axis, and b) to stiffen the helical blade HB along a radial axis. In FIG. 9B, the helical blade HB', HB" is closed, preventing back flow of liquid and solids.

In FIG. 9A and FIG. 9B, four elongate members EM" are positioned on the helical blades HB, HB', HB". It is to be understood, that more or fewer elongate members EM" may be adapted to the helical blades HB. HB', HB", depending on the geometry of the helical blades HB, HB', HB".

The following is a list of Items, according to the invention:

1.1. A separating screw conveyor for a pyrolysis system adapted to upcycle a mixed waste stream, the screw conveyor comprising:

-an axle with a peripheral surface extending along a longitudinal axis and having an inlet end and an outlet end,

1.2. The screw conveyor according to Item 1, wherein the axle is positioned at an oblique angle relative to a horizontal axis, between the inlet end and the outlet end.

1.3. The screw conveyor according to Item 2, wherein the oblique angle is in the range from 5 to 35 degrees, such as 15 to 25 degrees, preferably approximately 20 degrees relative to a horizontal axis.

1.4. The screw conveyor according to any of the preceding Items wherein the outlet end is positioned vertically higher than the inlet end. 1.5. The screw conveyor according to any of the preceding Items, wherein a plurality of radial connecting members extend radially between the helical blade and the peripheral surface of the axle.

1.6. The screw conveyor according to any of the preceding Items, wherein a pitch of flight of at least a portion of the helical blade is between 1: 1 and 1: 5.

1.7. The screw conveyor according to any of the preceding Items, wherein a pitch of flight of the helical blades varies along the length axis of the axle.

1.8. The screw conveyor according to any of the preceding Items, wherein the pitch of flight varies between 1: 1 and 1: 5 along the length axis of the axle.

1.9. The screw conveyor according to any of the preceding Items, wherein the pitch of flight reduces from the inlet end towards the outlet end.

1.10. The screw conveyor according to any of the preceding Items wherein a radial height (BH) of the helical blade is defined between an outer edge and an inner edge of said helical blade, and wherein said radial height is between 50 and 90 mm.

1.11. The screw conveyor according to any of the preceding Items, wherein a ratio, R, of the radial height, BH, of the helical blade to distance, d, where d is defined as the distance of gap between the inner edge of the helical blade and the peripheral surface of the axle, is defined by R = BH/d, and R is between 0.5 and 2.

1.12. The screw conveyor according to any of the preceding Items, wherein a gap area between the inner edge of the helical blade and the peripheral surface of the axle is between 0.1 and 2 of an area of the helical blade.

1.13. The screw conveyor according to any of the preceding Items, wherein at least one elongate member extends between at least two adjacent helical windings of the helical blade at or near an outer edge of said blade. 1.14. A processing chamber, the processing chamber adapted to be a section in a multi-section pyrolysis system for upcycling mixed waste streams, the processing chamber comprising:

-at least a first screw conveyor according to any of Items 1 to 13,

1.15. The processing chamber according to Item 14, further comprising one or more heating elements arranged in or on said chamber, the heating elements adapted to heat the mixed waste stream.

1.16. The processing chamber according to item 14 or 15 further comprising one or more sensors adapted to measure one or more of temperature, texture, viscosity or porosity of the mixed waste stream.

1.17. The processing chamber according to any of Items 14 to 16, wherein the processing chamber is a pyrolysis reactor adapted to upcycle at least a portion of the mixed waste stream during heating, such as to convert a portion of the mixed waste stream into an oil product.

1.18. The processing chamber according to any of Items 14 to 17 further comprising a motor adapted to rotate at least the axle of the screw conveyor.

1.19. The processing chamber according to any of Items 14 to 18 further comprising a second screw conveyor according to any of Items 1 to 13, the second screw conveyor arranged within the processing chamber substantially parallel to the first screw conveyor.

1.19. The processing chamber according to Item 19, wherein the first and second screw conveyors are adapted to operate in different phases of flight. 1.20. The processing chamber according to Item 19, wherein the first and second screw conveyors are adapted to operate at opposite phases of flight.

1.21. A pyrolysis system for upcycling mixed waste streams, the system comprising the screw conveyor according to any of Items 1 to 13 or the processing chamber according to any of Items 14 to 21, the system further comprising:

-a carbon container, and

1.22. The pyrolysis system according to Item 21, when dependent on any of Items 14 to 20, wherein the de-gasser is directly or indirectly fluidically connected to the processing chamber.

1.23. The pyrolysis system according to Item 22, wherein the de-gasser is arranged substantially horizontally and the processing chamber is arranged substantially oblique or inclined, relative to said de-gasser.

1.24. A method of separating a stream of mixed waste material comprising waste solids and waste liquids in a pyrolysis system, the method comprising:

-providing a screw conveyor according to any of Items 1 to 13 or a processing chamber according to any of Items 14 to 20, -feeding the mixed waste material at the inlet or inlet end, -separating the waste liquids from the waste solids by rotating the axle, and

1.25. The method according to Item 24, wherein the mixed waste material comprises up to 25 % waste solids. 1.26. The method according to Item 24 or 25, wherein at least 90% of the waste solids are conveyed to an associated section of the pyrolysis system.

1.27. Use of a screw conveyor according to any of Items 1 to 13, for the upcycling of a mixed waste stream into an upcycled material or product, such as an oil or gas product, preferably such as a fuel oil or fuel gas.

1.28. A method of manufacturing an upcycled material, such as oil, from a mixed waste stream, the method comprising the following steps:

-providing a pyrolysis system according to Item 21, -providing a mixed waste stream, -processing the mixed waste stream through the pyrolysis system, and -providing oil from the mixed waste stream, wherein at least a portion of the mixed waste stream is processed into ash or black carbon.

In short, the present invention relates to a separating screw conveyor for a processing chamber of a pyrolysis plant. The screw conveyor comprises an axle or shaft with a peripheral surface extending along a longitudinal axis and having an inlet end and an outlet end. The screw conveyor further comprises a helical blade, the helical blade extending helically around the peripheral surface, along the longitudinal axis of the axle, the helical blade configured with a pitch to flight the mixed waste stream upon rotation of the axle, wherein the helical blade is arranged radially at a distance (d) from the peripheral surface of the axle to enable for a portion of a mixed waste stream to move from between helical windings of the helical blade, near the peripheral surface of the axle, upon rotation of said axle. The distance between the axle and the helical blade enables for liquid portions of the mixed waste stream to flow in a direction opposite the flight direction, thus enabling the screw conveyor to separate at least solid waste from liquid waste during the upcycling process.

Although the present invention has been described in connection with the specified embodiments, it should not be construed as being in any way limited to the presented examples. The scope of the present invention is set out by the accompanying claim set. In the context of the claims, the terms "comprising" or "comprises" do not exclude other possible elements or steps. Also, the mentioning of references such as "a" or "an" etc. should not be construed as excluding a plurality. The use of reference signs in the claims with respect to elements indicated in the figures shall also not be construed as limiting the scope of the invention. Furthermore, individual features mentioned in different claims, may possibly be advantageously combined, and the mentioning of these features in different claims does not exclude that a combination of features is not possible and advantageous.

Claims

1. A separating screw conveyor (113) for a pyrolysis system adapted to upcycle a mixed waste stream, the screw conveyor comprising:

-an axle (A) with a peripheral surface (PS) extending along a longitudinal axis and comprising an inlet end and an outlet end,

-a helical blade (HB), the helical blade extending helically around the peripheral surface, along the longitudinal axis of the axle, the helical blade configured with a pitch to flight the mixed waste stream upon rotation of the axle, wherein the helical blade is arranged radially at a distance (d) from the peripheral surface of the axle to enable for a portion of the mixed waste stream to move from between helical windings (W, W', W", Wn) of the helical blade, near the peripheral surface of the axle.

2. The screw conveyor according to claim 1, wherein the axle is positioned at an oblique angle relative to a horizontal axis, between the inlet end and the outlet end.

3. The screw conveyor according to claim 2, wherein the oblique angle is in the range from 5 to 35 degrees, such as 15 to 25 degrees, preferably approximately 20 degrees relative to a horizontal axis.

4. The screw conveyor according to any of the preceding claims wherein the outlet end is positioned vertically higher than the inlet end.

5. The screw conveyor according to any of the preceding claims, wherein a plurality of radial connecting members extend radially between the helical blade and the peripheral surface of the axle.

6. The screw conveyor according to any of the preceding claims, wherein a pitch of flight of at least a portion of the helical blade is between 1: 1 and 1:5, wherein between 1 and 5 rotations of the axle conveys the mixed waste stream between a winding (W) and an adjacent winding (W'), such as between 1:2 and 1:4 wherein between 1 and 4 rotations of the axle conveys the mixed waste stream between a winding (W) and an adjacent winding (W').

7. The screw conveyor according to any of the preceding claims, wherein a pitch of flight of the helical blades varies along the length axis of the axle.

8. The screw conveyor according to any of the preceding claims, wherein the pitch of flight reduces from the inlet end towards the outlet end.

9. The screw conveyor according to any of the preceding Items, wherein the pitch of flight reduces from the inlet end towards the outlet end.

10. The screw conveyor according to any of the preceding claims wherein a radial height (BH) of the helical blade is defined between an outer edge (RP) and an inner edge (IE) of said helical blade, and wherein said radial height is between 50 and 90 mm.

11. The screw conveyor according to any of the preceding claims, wherein a ratio, R, of the radial height, BH, of the helical blade to distance, d, where d is defined as the distance of gap between the inner edge (IE) of the helical blade and the peripheral surface (PS) of the axle, is defined by R = BH/d, and R is between 0.5 and 2.

12. The screw conveyor according to any of the preceding claims, wherein a gap area (GA) between the inner edge of the helical blade and the peripheral surface of the axle is between 0.1 and 2 of an area (BA) of the helical blade.

13. The screw conveyor according to any of the preceding claims, wherein at least one elongate member (EM, EM') extends between at least two adjacent helical windings of the helical blade at or near an outer edge (RP) of said blade.

14. The screw conveyor according to any of claims 1 to 12, wherein at least one elongate member extends between at least two adjacent helical windings of the helical blade, the at least one elongate member positioned radially centered between the edge of the helical blade and the peripheral surface of the axle.

15. The screw conveyor according to any of the preceding claims, the axle comprising at least a first and second section, the first section comprising the helical blade (HB) according to any of claims 1 to 14, the second section comprising a second helical blade (HB'), the second helical blade extending from the peripheral surface of the axle, preventing the mixed waste stream to move from between helical windings of the second helical blade.

16. The screw conveyor according to claim 15, the axle further comprising a third section, the third section comprising a third helical blade (HB"), the third helical blade extending from the peripheral surface of the axle, preventing the mixed waste stream to move from between helical windings of the third helical blade.

17. The screw conveyor according to claim 16, the first section of the axle arranged in between the second and the third section, the helical blade (HB) arranged in between the second helical blade (HB') and the third helical blade (HB").

18. A processing chamber, the processing chamber adapted to be a section in a multi-section pyrolysis system for upcycling mixed waste streams, the processing chamber comprising:

-at least a first screw conveyor according to any of claims 1 to 17,

19. The processing chamber according to claim 18, further comprising one or more heating elements arranged in or on said chamber, the heating elements adapted to heat the mixed waste stream.

20. The processing chamber according to claim 18 or 19 further comprising one or more sensors adapted to measure one or more of temperature, texture, viscosity or porosity of the mixed waste stream.

21. The processing chamber according to any of claims 18 to 20, wherein the processing chamber is a pyrolysis reactor adapted to upcycle at least a portion of the mixed waste stream during heating, such as to convert a portion of the mixed waste stream into an oil product.

22. The processing chamber according to any of claims 18 to 21 further comprising a motor adapted to rotate at least the axle of the screw conveyor.

23. The processing chamber according to any of claims 18 to 22 further comprising a second screw conveyor according to any of claims 1 to 17, the second screw conveyor arranged within the processing chamber substantially parallel to the first screw conveyor.

24. The processing chamber according to claim 23, wherein the first and second screw conveyors are adapted to operate in different phases of flight.

25. The processing chamber according to claim 23, wherein the first and second screw conveyors are adapted to operate at opposite phases of flight.

26. A pyrolysis system for upcycling mixed waste streams, the system comprising the screw conveyor according to any of claims 1 to 17 or the processing chamber according to any of claims 18 to 25, the system further comprising:

-a carbon container, and -a de-gasser, wherein at least the carbon container and the de-gasser are directly or indirectly fluidically connected.

27. The pyrolysis system according to claim 26, when dependent on any of claims 18 to 25, wherein the de-gasser is directly or indirectly fluidically connected to the processing chamber.

28. The pyrolysis system according to claim 27, wherein the de-gasser is arranged substantially horizontally and the processing chamber is arranged substantially oblique or inclined, relative to said de-gasser.

29. A method of separating a stream of mixed waste material comprising waste solids and waste liquids in a pyrolysis system, the method comprising:

-providing a screw conveyor according to any of claims 1 to 17 or a processing chamber according to any of claims 18 to 25, -feeding the mixed waste material at the inlet or inlet end, -separating the waste liquids from the waste solids by rotating the axle, and

30. The method according to claim 29, wherein the mixed waste material comprises up to 25 % waste solids.

31. The method according to claim 29 or 30, wherein at least 90% of the waste solids are conveyed to an associated section of the pyrolysis system.

32. The method according to any of claims 29 to 31, when dependent on the processing chamber according to any of claims 18 to 25, further comprising the following steps:

-operating the screw conveyor according to any of claims 15 to 17, wherein the specific fill level intersects with the first section of the axle and the second section of the axle is above or below the fill level.

33. Use of a screw conveyor according to any of claims 1 to 17, for the upcycling of a mixed waste stream into an upcycled material or product, such as an oil or gas product, preferably such as a fuel oil or fuel gas.

34. A method of manufacturing an upcycled material, such as oil, from a mixed waste stream, the method comprising the following steps:

-providing a pyrolysis system according to any of claims 26 to 28, -providing a mixed waste stream,