EP4368293A1

EP4368293A1 - Compact solid waste separator

Info

Publication number: EP4368293A1
Application number: EP23202724.3A
Authority: EP
Inventors: Zoltán NAGY; Zoltán Ifj. Nagy; Barnabás Csöke; József Faitl
Original assignee: 3b Hungaria Kft
Current assignee: 3b Hungaria Kft
Priority date: 2022-11-14
Filing date: 2023-10-10
Publication date: 2024-05-15
Also published as: HUP2200446A1

Abstract

The compact solid waste separator comprises an airflow separator module (I), magnetic separator modules (II, III) and an eddy current separator module (IV). The upper part of the enclosure (1) of the unit is equipped with a waste receiving hopper (1.1), a variable-speed outfeed conveyor (2), a nozzle (4) with an adjustable angle of inclination and an adjustable cross-section of air blow, air jet baffle plates (3) and a gravity sedimentation chamber (18). Inside the enclosure (1), rotating drum separator (8, 10, 16) with adjustable speed and axial position for the separation of different waste fractions, and outfeed conveyors (6, 7, 11, 12.1, 14, 15, 17) for the removal of separated waste fractions are installed. The first magnetic separator module (II) comprises a rotating drum (5) with magnets built into it, and the second magnetic separator module (III) comprises an upper magnetic separator (12). The eddy current separator module (IV) comprises an eddy current drum separator (13) with a pole motor (13.1) integrated in a separate drum.

Description

The subject of the invention is a compact solid waste separator, in particular for the processing of mixed solid waste (hereinafter referred to as "MMSW").
The basic aim of the circular economy is to reintroduce minerals and biological materials into the human consumption cycle as secondary raw materials after consumption. In the case of municipal solid waste (MSW), in addition to energy and material recovery, the risk of waste must also be eliminated and the waste must be treated. Despite of using modern systems for the selective collection of municipal waste, residual waste is still generated, this is known as mixed municipal solid waste (MMSW).
Separators are important equipment for the preparation and the processing of waste, where the separation of the components is based on the final sedimentation rate of the particles, whether or not the airflow grabs the particles. Magnetic separators are widely used in the industry as stand-alone devices for the separation of materials that can be magnetized. A common feature of magnetic separators is that a permanent magnet or electromagnet is placed inside a transporting device, such as a conveyor belt or a drum. The magnet attracts the particles that can be magnetized and the transport device transports them to the right place. Eddy current separators have been gaining ground in recent decades because they have proven to be suitable for extracting metals from waste based on conductivity. The following document provides a comprehensive description of the commonly used types of separators and their principle of operation: H. Schubert: Eddy-current Separation - Fundamentals, Separators, Application. Aufbereitungs-technik 35 (1994) Nr. 11.
There are a number of plants across Europe using mechanical-biological technologies to process MMSW. Airflow, magnetic and eddy current separators are widely used in these plants.
In 2015, we recognised the need for a solution to replace the common separators in the processing plants of MMSW, which would allow for reduced process losses and energy-efficient operation through environmentally friendly technological solutions. We also recognised that it is preferable to incorporate these separators - in a modular way - into a single unit in terms of space, energy and environmental impact. In the light of the above, we have filed a patent application for a "Combined airflow magnetic and electrical (hereinafter: CAME) separator", which is protected by Hungarian patent registration number 231142 B .
Figure 1 illustrates the modular CAME separator comprising an airflow separator (I), a magnetic separator (II) and an eddy current separator (III). The airflow separator (I) comprises a feeder (A) containing the waste to be processed, underneath it is a vibratory feeder (1) directed onto a rotating drum (3), under which a nozzle (2) is placed. An outfeed conveyor belt (8) is installed underneath the rotating drum (3) to transport light products (B). Baffle plates (4, 5) and air vent manifolds (6, 7) are arranged in the top cover of the unit. The magnetic separator (II) is a magnetic drum (9) placed in the space envelope below the drum being rotated (3). The eddy current separator (III) comprises the feeder element (F), the impeller (10) arranged underneath, the wear element (K) and the adjustable separator plate mounted underneath.
The CAPE separator has four or five products: the foil-paper or otherwise known as 2D product (B), the inert product (C) containing stones, glass and bulk biological materials, the 3D product (D) containing mainly plastic bottles and flasks, and the aluminium product (E). The fifth product is generated when the eddy current separator has a third, stainless steel product outlet built into the equipment.
Operating experience gained with the CAME separator has revealed the following issues:

The vibratory material feed applied is difficult to control, the feed rate of the particles falling on the nozzle cannot be adjusted.
The nozzle cannot achieve a uniform speed profile with a constant air velocity along the longitudinal axis of the nozzle, as the nozzle wall restricts the airflow at the edges.
The CAME separator can display what is known as the air jet entrainment phenomenon, when the air jet exiting the nozzle grabs air from above and below. This can result in a vortex at the top and the bottom, creating a static pressure distribution that causes the airflow to flow in a different direction from the nozzle or to hit the top wall or the separation cylinder.
Some of the thin-walled Fe particles in the nozzle airflow are blown by the nozzle onto the eddy current separator, which can cause the thin-walled cladding to burn out.
If the position of the third separating cylinder is not adjustable, the equipment cannot be controlled for the waste in question.
In the CAME separator, the feed rate of the particles sliding onto the eddy current separator cannot be controlled and therefore the operation of the separator cannot be adjusted to the specific waste stream.
In the CAME separator, the simple baffle plate of the eddy current separator that separates the electrically conductive and non-conductive particles catches fibrous materials, resulting in clogging and faulty separation.

Based on the findings on operating the CAME separator, we aimed to remedy the identified shortcomings by providing a new type of waste separator.
The objective is achieved by a compact solid waste separator consisting of an airflow separator module, magnetic separator modules and an eddy current separator module incorporated in a common enclosure. To coordinate the operation of the modules, the operation of the machines within modules can be controlled. The plant is specifically designed to enrich the pre-crushed and screened coarse product of MMSW, but it is also suitable for the enrichment of separately collected single or multi-component municipal solid waste and even electronic waste.
The compact solid waste separator according to the invention produces the following products from the waste fed in:

1. Fe-1: A product containing compressed or thick-walled metals that can be magnetised.
2. Si: An inert product containing mainly stone gravel and glass particles and heavy biological and other heavy particles.
3. Fe-2: Contains thin-walled particles that can be magnetised.
4. SS: Stainless steel product.
5. AI: Aluminium (electrically conductive) product.
6. 3D: Contains mainly three dimensional plastic particles, bottles and cylinders.
7. 2D: Contains mainly two-dimensional paper and plastic particles.

The bio-fraction has already been separated from the waste to be processed. Following classification, MMSW is received by the airflow separator module. A waste receiving hopper is installed in the upper part of the module enclosure and a feed conveyor with adjustable speed is installed underneath. A nozzle with an adjustable angle of inclination and an adjustable cross-section of air blow is mounted under the feed conveyor in an acute angle. The nozzle consists of a throttle drum and connected to it is a blowpipe divided into segments by blades. The lower part of the blowpipe is an adjustable baffle plate. In the upper part of the enclosure, downstream from the nozzle, there are air jet deflectors.
Downstream from the nozzle, the enclosure incorporates a rotating drum separator with adjustable speed and an adjustable lever for separating Si and 2D, 3D products, followed by a rotating drum with adjustable speed and an adjustable lever for separating the 2D and 3D products, under which a 2D product outfeed conveyor is installed. The 2D product outfeed conveyor delivers the 2D product to the gravity sedimentation chamber of the enclosure. The module is therefore used to separate the 2D product from the waste stream.
The vertical and horizontal position of the rotating drums separating the different types of waste is adjustable. The primary function of the rotating drums is to transport the particles coming into contact with them into the correct product channel, which is particularly problematic for fibrous or deformable particles.
The first magnetic separator module is arranged under the nozzle and the separated Fe-1 and Si products are removed from the enclosure with two outfeed conveyors.
The second magnetic separator module consists of a Fe-2 product outfeed conveyor and an upper magnetic separator arranged below the 2D product outfeed conveyor.
Fe particles with a low final sedimentation rate, such as thin-walled Fe cans and beverage cans, are blown by the nozzle in the direction of the 3D product line. These particles, however, cannot get onto the eddy current separator because they would stick to the rotating pole motor and burn out the thin-walled casing or the conveyor belt. The second magnetic separator integrated in the equipment is positioned above the infeed conveyor of the eddy current separator conveying the loosened material, thus providing a good efficiency of separation of ferrous metals.
In the eddy current separator module, there is a variable speed infeed conveyor arranged below the second magnetic separator module for feeding the waste to the eddy current drum separator with a pole motor integrated in a separate drum. An SS product outfeed conveyor is installed under the infeed conveyor. Downstream from the eddy current drum separator, a rotating drum separator with adjustable speed and shaft position and a lever is installed in the enclosure to separate Al and 3D products, below which there is an outfeed conveyor for Al products, followed by an outfeed conveyor to remove 3D products from the enclosure.
The infeed conveyor and the pole motor are two separate structural components, which has its benefits as the infeed rate - materials sliding onto the separator plate - and the speed of the drum and the pole motor can be controlled independently and the separator can be adjusted more effectively for a specific type of waste.
The objectives of the invention may be achieved by the compact solid waste separator described in claim 1, the preferred implementation methods of which are described in the subclaims.
Our invention is described in detail with reference to the accompanying drawings, where:

figure 1 shows the structure of the CAME separator;
figure 2 shows the structural design of the compact solid waste separator according to the invention; and
figure 3 shows the nozzle design.

Our invention, illustrated in Figure 2, is a complex device arranged in 1 enclosure and comprises separate modules, namely, (I) the airflow separator module, (II) the first magnetic separator module, (III) the second magnetic separator module and (IV) the eddy current separator module. The equipment can be dismantled into modules.
The airflow separator module (I) is located in the upper part of the enclosure of the compact solid waste separator (hereinafter: separator) (1), where the waste is loaded into the separator. The dispatched waste is fed through (1.1) an infeed hopper to (2) the infeed conveyor. The (2) infeed conveyor is a rubber belt transportation device of a familiar design, wherein one driven and one free running drum is located at each end. The speed of the (2) conveyor drive motor can be controlled by a variable-frequency drive, so that the mass flow rate of the separator infeed can be adjusted. The speed of the (2) infeed conveyor can be used to control the infeed capacity of the module, and thus the amount of MMSW and the layer thickness of the waste on the (2) infeed conveyor.
The material falls down at the end of the (2) infeed conveyor and the movement of the falling particles is intersected by the air jet exiting the (4) nozzles. The (4) nozzle separates the heavy and light waste fractions (Si and 2D, 3D products), blowing the light 2D and 3D fractions towards the interior of the enclosure (1). The angle of the (4) nozzle can be adjusted to control the angle of the injected air jet and thus the separation of Si and 2D, 3D products. The (4) nozzle is supplied with air via (4.3) air inlet pipes (see Figure 3) at the pressure side of an external fan (not part of the separator).
In the upper part of the (1) enclosure, after the (4) nozzle, (3) air jet deflectors are installed to moderate the deflection of the jet, reduce the formation of a vortex above, thus preventing the jet entrainment phenomenon.
Of the waste particles falling from the (2) infeed conveyor, the particles with a final sedimentation rate higher than the final separation sedimentation rate - the so-called heavy fraction (Si product) - slide down the chute of the (2) infeed conveyor and are deposited on the (5) rotating drum of the (II) first magnetic separator module. The final sedimentation rate of the particles depends on their size, density and shape. Particles with a lower final sedimentation rate, the so-called light fraction (2D, 3D products) are caught by the air jet. Of these, lightweight particles with a typically three-dimensional shape, such as plastic containers for detergents and other cosmetics, or aluminium or iron beverage cans, are only carried a small distance. Some of these hit the (8) rotating drum separator installed after the (4) nozzle, however, the rotation of the drum also sends these particles to the right place. Because of the adjustability of the fraction separation, it is important that the position of the (8) separation drum can be adjusted by some installation work and its bearing can be moved vertically and horizontally and then clamped in a fixed position. The angle of the lower (8.1) lever of the (8) rotary drum can also be adjusted, which is also necessary to control the separation.
The 3D particles with a lower final sedimentation rate pass through the (8) rotating drum separator and are transferred to the variable speed (9) infeed conveyor of the (IV) eddy current separator module. Lightweight particles, such as plastic films and sheets of paper with a typically two-dimensional shape, are fed into the 2D product of the separator because the air jet can get these particles through the other (10) rotating drum separator. This (10) rotating drum separator, also having a (10.1) lever, has a similar design and function as the previous (8) rotating drum separator. The sedimentation of the light 2D particles begins at the 2D product (11) outfeed conveyor installed downstream of the (10) rotating drum separator and continues at the (18) gravity sedimentation chamber connected downstream of the separator at the upper end of the (1) enclosure.
Having fallen off the (2) infeed conveyor, heavy particles such as thick-walled iron particles, stone-pebble-ceramic particles, but also particles of high moisture paper block, bread, shoes, etc., fall through the air jet and are transported through a chute to the (II) first magnetic separator. Permanent magnets or electromagnets are incorporated in the (5) rotating drum of the (II) first magnetic separator, which causes the magnetizable particles (Fe-I product) to be transferred to the transversely oriented (6) outfeed conveyor. The fall of the non-magnetisable products falling off the (2) infeed conveyor is not affected by the (5) rotating drums, so these particles get into the inert product (Si product), which is taken out of the separator by another transversely arranged (7) outfeed conveyor.
The magnetizable particles must be separated from the lightweight 3D particles coming off the (8) rotating drum separator and falling on the (9) infeed conveyor, because if they reach the (13) eddy current drum separator of the (IV) eddy current separator module, they can be trapped by the strong magnetic field against the movement of the (9) infeed conveyor, and even causing the (9) infeed conveyor to burn or catch fire. The thin-walled cans of cat and dog food are typically deposited here because they are also blown away by the air jet. The (12) top belt magnetic separator of general design of the (III) second magnetic separator module is located above the (9) infeed conveyor and it separates the lightweight magnetizable 3D particles and transversely removes them from the (1) enclosure by means of the transversely arranged (12.1) outfeed conveyor.
The (IV) eddy current separator module is not of conventional design. The (13.1) pole motor comprising glued permanent magnets rotating at a high circumferential speed, is not installed in the rotating drum of the (9) infeed conveyor, but is housed in a separate (13) eddy current drum separator installed downstream of a (13.2) separator plate. This means that the speed of the (9) infeed conveyor can be adjusted across a wide range to match the specific volume of material, so that the material feed rate to the (13) eddy current drum separators can also be controlled, resulting in a much sharper separation. An additional advantage is that there is an insignificant gap between the (13.1) pole motor in the standalone drum and the particles, because the (9) infeed conveyor is not there, resulting in significantly higher Lorentz force for separation in comparison with the conventional design. The electrically conductive particles such as aluminium beverage cans among the lightweight 3D particles induce eddy currents and are then ejected by the resulting Lorentz force. In conventional eddy current separators, a simple baffle plate is used to separate the conductive and non-conductive products, but this solution does not provide a sharp separation, so the separator according to our invention also features a (16) rotating drum separator with a (16.1) lever at this location, whose horizontal and vertical position can be adjusted by some installation work as described above. The 3D conductive product (Al product) is removed from the (1) enclosure by a (17) transversally arranged outfeed conveyor. Municipal waste may, at times, contain small amounts of stainless steel particles. The thin-walled stainless steel particles (SS product) are also fed onto the (9) infeed conveyor belts and then transferred to the (14) outfeed conveyor, which is positioned transversely under the (13.1) pole motor. Lightweight 3D particles, such as plastic bottles and beverage bottles, are not electrically conductive, and therefore they fall onto the lengthwise (15) outfeed conveyor that removes these products from the (1) enclosure.
Figure 3 shows the structural design of the nozzle in two views. The air supplied to the (4) nozzle is fed through the (4.3) flexible air supply hoses into a (4.1) throttle drum. This flexible guiding allows the angle of the (4) nozzle to be adjusted even during operation, making the separator insensitive to vibrations. The (4.1) throttle drum is connected to the (4.2) blowpipe (4.4) divided into segments by blades, the lower part of which is fitted with a (4.5) comb-shaped baffle plate with an adjustable angle of inclination, driven by an (4.6) electric motor shaft.
As the (4.2) blowpipe exerts flow resistance, air is blocked in the (4.1) throttle drum and, as a result, the speed distribution of the air being discharged from the (4) nozzle becomes more uniform along the longitudinal axis of the (4) nozzle. Without the (4.1) throttle drum, the air speed at the edges of the (4) nozzle would be significantly reduced due to wall friction, which would impair the sharpness of the waste separation. The (4.1) throttle drum alone is not enough to produce a uniform air speed, but the (4.4) blades with the right pitch and orientation are able to generate an air jet of uniform speed distribution. Thus, by using a combination of the (4.1) throttle drum and the (4.4) blades, it is possible to achieve a uniform air speed distribution on the (4) nozzle. The jet velocity of the air stream coming out of the (4) nozzle is the most important characteristic of the (I) airflow separator module, because it determines the final sedimentation rate at which the separator separates the heavy (Si product) and light (2D, 3D product) waste fractions. The adjustable angle of the (4.5) baffle plates allows the outlet cross-section of the (4) nozzles to be adjusted, as well as the mouth opening of the 2 blowpipes, and therefore the outlet air speed can be adjusted during operation according to the law of continuity, so that the separation on the (I) airflow separator module can be adjusted during operation to match the quantity and quality of the waste being fed in.
It can be seen from the above that the invention is suitable in all respects for achieving the objectives set out, and that it makes it possible to reduce technological losses by using environmentally friendly technical solutions.

Reference numbers

I - airflow separator module
II - first magnetic separator module
III - second magnetic separator module
IV - eddy current separator module
1 - enclosure
1.1 - receiving hopper
2 - infeed conveyor
3 - air jet baffle plate
4 - nozzle
4.1 - throttle drum
4.2 - blowpipe
4.3 - air supply hose
4.4 - blade
4.5 - baffle plate
4.6 - shaft
5 - rotating drum
6 - (Fe-1 product) outfeed conveyor
7- (inert product) outfeed conveyor
8- (2D+3D product) rotating drum separator
8.1 - lever
9 - infeed conveyor
10 - (2D/3D product) rotating drum separator
10.1 - lever
11 - (2D product) outfeed conveyor
12 - magnetic separator with belt on top
12.1 - (3D product) outfeed conveyor
13 - eddy current drum separator
13.1 - pole motor
13.2 - separator plate
14 - (stainless steel product) outfeed conveyor
15 - (3D product) outfeed conveyor
16 - (AI/3D product) rotating drum separator
16.1 - lever
17 - (Al product) outfeed conveyor
18 - gravity sedimentation chamber

Claims

A compact solid waste separator comprising an airflow separator module (I), magnetic separator modules (II, III) and an eddy current separator module (IV) integrated in an enclosure (1), wherein the airflow separator module (I) has a waste receiving hopper (1.1), a nozzle (4) and, downstream of the nozzle (4), air baffle plates (3), characterized in that
- a variable-speed infeed conveyor (2) is installed under the hopper (1.1), under which, positioned in an acute angle to it, a (4) nozzle with an adjustable angle of inclination and an adjustable cross-section of air blow is installed;

- after the nozzle (4), rotating drum separators (8, 10) of adjustable speed and axis position are arranged for the separation of Si and 2D, 3D products;

- there is a gravity sedimentation chamber (18) in the upper part of the enclosure (1);

- the first magnetic separator module (II) is arranged under the nozzle (4);

- the second magnetic separator module (III) is arranged under the rotating drum separator (10),

- the eddy current separator module (IV) has a variable-speed infeed conveyor (9) arranged below the second magnetic separator module (III), downstream of which an eddy current drum separator (13) with a pole motor (13.1) integrated in a separate drum is arranged,

- a rotating drum separator (16) with adjustable speed and axis position is installed downstream of the eddy current drum separator (13) for the separation of Al and 3D products.
The compact solid waste separator according to claim 1, characterized in that the (4) nozzle is formed by a throttle drum (4.2) with air supply hoses (4.3) and a blowpipe (4.2) connected thereto and divided into segments by blades (4.4);
The compact solid waste separator according to any one of claims 1 to 2, characterized in that the lower structural element of the blowpipe (4.2) is a variable angle comb-shaped baffle plate (4.5).
The compact solid waste separator according to any one of claims 1 to 3, characterized in that the baffle plate (4.5) is fixed to a shaft (4.6) driven by an electric motor.
The compact solid waste separator according to claim 1, characterized in that the first magnetic separator module (II) comprises a rotating drum (5) with magnets built into it.
The compact solid waste separator according to claim 1, characterized in that the second magnetic separator module (III) comprises an upper magnetic separator (12).
The compact solid waste separator according to claim 1, characterized in that the rotating drum separators (8, 10, 16) features baffle plates (8.1, 10.1, 16.1).
The compact solid waste separator according to claim 1, characterized in that outfeed conveyors (6, 7, 11, 12.1, 14, 15, 17) for removing separated waste products are installed in the enclosure (1).