EP3871776B1 - Device for treating a mixture of materials consisting of substitute fuel and impurities - Google Patents

Description

The present invention relates to a method for processing a material mixture consisting of substitute fuel and impurities, which is classified, crushed and dried in the device.

The substitute fuel, also known as secondary fuel, includes in particular solid waste, which can be used together with conventional fuels, especially in cement, lime, lignite or industrial power plants as well as in waste incineration plants or as the sole fuel in substitute fuel power plants. The solid waste consisting, for example, of commercial waste and/or household waste usually still has impurities, such as glass or metals, after coarse comminution. It is therefore known to carry out a separation after the coarse comminution and, if necessary, to further comminute the refuse-derived fuel. DE 102015005604 A1 discloses a device for processing a material mixture consisting of refuse derived fuel and impurities according to the preamble of claim 1.

It is therefore the object of the present invention to provide a device with which it is possible both to separate the impurities from the refuse-derived fuel and to carry out a particularly efficient comminution of the refuse-derived fuel.

The object is solved by a device having the features of the independent claim. Advantageous developments of the device are in specified in the dependent claims and in the description, with individual features of the advantageous developments being able to be combined with one another in a technically meaningful manner.

The object is achieved by a device for processing a material mixture consisting of refuse derived fuel and impurities, having a vertically aligned central feed, a separating device arranged below the central feed, a rotor mill, with the rotor mill being arranged above the separating device and surrounding the central feed, and a flow device for generating an upward gas flow, wherein the material mixture can be introduced into the feed and after being introduced into the feed sinks to the separating device, the impurity in the separating device being separated at least partially as an impurity fraction from the material mixture and the Separated contaminants separate material mixture rises with the gas flow to the rotor mill, wherein the ascending material mixture is comminuted in the rotor mill. Provision is also made for the rotor mill to be designed in multiple stages, with a separating device being arranged between each stage of the rotor mill, with the material mixture not retained by the separating device being further comminuted in the following stage.

The material mixture can be introduced into the feed, for example via a funnel or another feed device, with the feed being oriented vertically, so that the material mixture introduced into the feed sinks in the feed. The feeder is hollow on the inside so that the material mixture can sink undisturbed. For example, the feed can be formed by a tube (hollow cylinder).

A separating device is arranged below the central feed, which comprises, for example, a rotatably drivable spreading disc. The separating device is designed in particular in such a way that at least a large proportion of the contaminants can be separated (classified) from the material mixture, with the separated contaminants being able to be removed from the device in a suitable manner.

A flow device is provided for the separation/sifting, by means of which an upwardly rising gas flow can be generated at least in the area of the separating device, in particular in the area of the scattering plate of the separating device, and the rotor mill. For this purpose, the flow device has in particular at least one gas inlet, which is preferably arranged in the lower area of the device, and at least one outlet in the upper area of the rotor mill. For example, heated air can be used as the gas.

In particular, it is provided here that the material mixture supplied through the central feed is thrown from the scattering disc into a space surrounding the scattering disc, in which space the gas flow rises, with the rising gas flow taking as far as possible only the refuse-derived fuel and a large part of the impurities in the scattering disc surrounding space drops. Drying of the substitute fuel taken along then also takes place with the gas flow.

The refuse-derived fuel entrained in the gas flow (and possibly unseparated impurities) is fed with the gas flow to the rotor mill, which is arranged above the separating device (spreading disc). The substitute fuel is crushed in the rotor mill by impact, shear and impact forces. For this purpose, the rotor mill preferably has at least one rotary driven tool that promotes the crushing of the refuse-derived fuel.

Preferably, the separating device (and in particular its spreading disc) and the tools of the rotor mill can be driven together in rotation (rotationally) about a vertically aligned axis. Particularly preferably, the feed can also be driven in rotation at the same time. The scattering plate can be connected in a rotationally fixed manner to the element (e.g. pipe) limiting the feed, with the at least one tool of the rotor mill preferably being attached to an outside of the element forming the central feed in its interior. Thus, only one drive for generating the rotary movement has to be provided. The drive is arranged in particular in the lower area of the device and can, for example, generate a rotary movement with 500 to 1000, preferably with 700 to 900 revolutions/min.

The invention now provides that the rotor mill has at least and preferably exactly two or three stages, optionally four stages, with at least one separating device (e.g. a sieve) being arranged between the stages of the rotor mill, so that particles of the material mixture mainly containing refuse-derived fuel particles larger than the particle size set by the separation device can be retained in the previous stage, while particles of the material mixture with a smaller size can pass to the following stage. In the following stage of the rotor mill, the material mixture is then further comminuted. Due to the multi-stage nature of the rotor mill, alternative fuel with different average particle sizes can be provided with one device. The fraction of the material mixture drawn off from the first stage can, for example, have an average particle size between 60 and 200 mm, while the fraction of the mixture drawn off from the second stage Material mixture may have an average particle size of, for example, 10 to 60 mm.

In this context, it is preferred if each stage of the rotor mill is assigned at least one outlet, via which the correspondingly comminuted material mixture, which mainly or at best exclusively contains refuse-derived fuel, can be drawn off.

The second and possibly also each further stage of the rotor mill are arranged in particular vertically above the first or preceding stage, with the tools of each stage preferably being driven by a single common drive.

While it is possible in principle to implement the separating device by suitable separating methods, it is preferred if the separating device comprises at least one screen between the stages of the rotor mill. A simple separating device is provided with such a sieve.

In one embodiment it can be provided that an annular space is formed, which surrounds the first stage of the rotor mill, wherein in particular a grid arrangement functioning as a sieve is arranged between the outer annular space and the tools of the first stage of the rotor mill. The material mixture comminuted in the first stage of the rotor mill can thus pass through the grid arrangement into the annular space, from which the comminuted material mixture can be drawn off through the at least one first outlet. If a large number (more than two) stages are formed, each stage following the first stage up to the last stage can also be assigned its own annular space, which is separated from the tools of the corresponding stage by a lattice arrangement.

In this context, provision can also be made for scraper elements, which can also be referred to as scraper elements, to be formed on a radially outer end of some tools of the (first stages of the) rotor mill, with which particles of the Material mixture can be detached from the lattice arrangement so that they can be fed to further crushing in the first or the corresponding stage.

In addition, it can be provided that a cleaning device is assigned to the separating device between the stages of the rotor mill, with which the material mixture retained by the separating device can be detached from the separating device. The dissolved material mixture can thus be fed to further comminution in the preceding stage, for which purpose pulsation of the gas flow is also possible, for example. Here, the cleaning device can also be driven in rotation together with the tools of the previous stage, so that a continuous release of the retained material mixture from the separating device is possible.

In one embodiment, it can also be provided that the rotor mill (and in particular also each stage of the rotor mill) has several, in particular more than 10, preferably more than 20, tools arranged vertically and offset from one another in the circumferential direction. This offset arrangement of the tools both in the circumferential direction and in the vertical direction results in a longer dwell time of the material mixture and thus more effective comminution of the material mixture, so that a higher degree of comminution can be achieved or the rotor mill can be realized with a lower height. However, the longer residence time also means that the material mixture dries better.

In this context, it is preferred if the rotor mill has a centrally arranged and rotationally driven hollow cylinder (which preferably also forms the central feed), on the outside of which the tools are attached, with the tools each individually extending radially outwards from the outside of the hollow cylinder . The tools are therefore in particular elongate elements which extend outwards from the hollow cylinder. Thus, in particular, the rising material mixture can flow through the entire area between the outside of the hollow cylinder and a radially spaced boundary of the rotor mill, with interaction with the tools being able to take place in the entire area.

Provision can be made for a group of tools and/or most tools to comprise flat wing elements which extend radially outwards. The wing elements are attached directly or indirectly to the outside of the hollow cylinder and are substantially longer in the radial direction (at least three times, preferably at least five times) as long as their width. In addition, the wing elements have a height that is less than their width, the wing elements being at least twice as wide, preferably four times as wide as they are high. It has been found that particularly efficient comminution of the material mixture is possible with such wing-like elements.

A further improvement in the comminution can be achieved in that the wing elements are set at an angle to a horizontal plane. The angle of attack is preferably 3° to 45°, particularly preferably 5° to 20° to the horizontal plane.

Provision can also be made for at least one tool or a plurality of tools, preferably most of the tools, to comprise a plate-shaped impact element which is arranged at a radial end of the tool, the plate-shaped impact element being oriented in particular vertically. With such a plate-shaped impact element, the comminution efficiency can be further increased.

In addition, it can be provided that at least one tool comprises a scraper element, which is arranged radially on the outside of the tool and is in contact with a wall of the rotor mill or the stage of the rotor mill that delimits the grinding chamber on the outside, the wall being formed, for example, by a grid arrangement can, which separates the grinding chamber from an annular space. With the scratching element, accumulation of particles of the material mixture on the inside of the wall can be prevented or removed.

The plate-shaped impact element or the scraper element can be attached, for example, to a radial end of the wing element of the tool described above.

Provision can also be made for at least one tool to be formed from a wire which is attached to the outside of the hollow cylinder. A wire is understood in particular to mean an element which extends outwards in an elongated manner from the hollow cylinder and whose width and height are approximately the same. The wire preferably has a circular cross-sectional configuration.

In a lower area of the rotor mill or in a lower area of a stage of the rotor mill, a large number (in particular more than 8 preferably more than 16) of tools each comprising a blade member are arranged, while a plurality of tools comprising a wire are arranged in an upper portion of the rotor mill or in an upper portion of a stage of the rotor mill.

For a particularly efficient comminution of the material mixture, it has been found that a group (more than 4) of tools can be arranged helically (i.e. on a helix) offset from one another, with several groups of tools being arranged one behind the other in the circumferential direction.

Figur 1:

eine Vorrichtung zum Aufbereiten eines aus Ersatzbrennstoff und Störstoff bestehenden Materialgemischs,

Figur 2:

eine Schnittdarstellung durch die Vorrichtung und

Figur 3:

eine Detailansicht der Vorrichtung.

The invention and the technical environment are explained below by way of example with reference to the figures. It show schematic

Figure 1:

a device for processing a mixture of materials consisting of substitute fuel and impurities,

Figure 2:

a sectional view through the device and

Figure 3:

a detailed view of the device.

The device shown in the figures for processing a material mixture consisting of substitute fuel and extraneous matter has a vertically oriented central feed 1 which is radially delimited by a hollow cylinder 12 . A funnel is formed above the feeder 1 through which the material mixture is fed into the feeder 1 .

A separating device 2 , which includes a spreading disc 14 , is formed below the central feed 1 . The scattering disk 14 is connected in a rotationally fixed manner to the hollow cylinder 12, so that the scattering disk 14 and the hollow cylinder 12 can be driven in rotation together.

Tools in the form of wing elements 8a and wires 8b are arranged on the outside of the hollow cylinder 12 so that they can be driven in rotation together with the hollow cylinder 12 about the longitudinal axis of the hollow cylinder. The tools 8a, 8b form a rotor mill 3 arranged above the separating device 2 .

The device also includes a flow device 4 with an inlet 15, a first outlet 7.1 and a second outlet 7.2. The flow device 4 can be operated by blowing in a gaseous operating medium at the inlet 15 or by sucking off the gaseous operating medium at the outlets 7.1 and 7.2. The interior of the device is designed in such a way that the operating medium entering through the inlet 15 flows upward past the radially outer edge of the scattering plate 14 into the rotor mill 3 .

The rotor mill 3 has a first stage 5.1, which is associated with the first outlet 7.1. The rotor mill 3 also has a second stage 5.2, to which the second outlet 7.2 is assigned. The tools 8a and 8b of the first stage 5.1 are surrounded radially by a grid arrangement 10 which separates the tools from an annular space 9. In addition, a separating device 6 in the form of a sieve is formed between the first stage 5.1 and the second stage 5.2.

The first stage 5.1 and the second stage 5.2 of the rotor mill 3 each comprise a multiplicity of blade elements 8a which are attached in groups in a helical manner to the outside of the hollow cylinder 12 and extend from the outside of the hollow cylinder extend radially outwards. The wing elements 8a are oriented at an angle of attack to a horizontal plane. Plate-shaped impact elements 13 are attached to the outer ends of the wing elements 8a. In contrast, scraper elements 11 are attached to some wing elements 8a, with which components of the material mixture retained by the lattice arrangement 10 can be detached from the lattice arrangement 10 . In the upper area of the first stage 5.1, scratching elements can also be attached indirectly to the hollow cylinder 12 as a cleaning device, with which material retained by the separating device 6 can be detached. In the upper area, the first stage 5.1 and the second stage 5.2 each have wires 8b as tools, which are attached to the outside of the hollow cylinder 12.

During operation, a material mixture consisting of refuse derived fuel and extraneous material is introduced into the vertically oriented central feed 1 , in which the material mixture sinks down to the separating device 2 comprising the spreading disc 14 . Due to the joint rotary motion of the scattering disk 14 and the hollow cylinder 12 limiting the feed 1, the material mixture is accelerated radially outwards at the latest when it reaches the scattering disk 14. The mixture of material passing over the outer radial edge of the scattering disc 14 is screened due to the rising gas flow, so that primarily impurities in the space surrounding the scattering disc 14 sink downwards, while the remaining material mixture, which mainly contains RDF, goes with the gas flow into the first stage 5.1 of the rotor mill 3 occurs.

In the first stage 5.1, the material mixture is comminuted by interaction with the tools 8a and 8b and with each other. Due to the vertically and circumferentially offset arrangement of the tools 8a, 8b, effective comminution can take place, with comminuted Material can pass through the grid arrangement 10 into the annular space 9, with this part of the material mixture being drawn off from the first outlet 7.1.

The material mixture passing through the separating device 6 is further comminuted in the second stage 5.2, so that the material mixture exiting the second outlet 7.2 has a smaller mean particle size than the material mixture exiting the first outlet 7.1.

With the device, not only can a particularly efficient comminution take place, it is also possible to provide a mixture of materials with different particle sizes.

reference list

1

feeding

2

separator

3

rotor mill

4

flow device

5.1

first stage

5.2

second step

6

separator

7.1

first outlet

7.2

second outlet

8a

wing element

8b

wire

9

annulus

10

grid arrangement

11

scratch element

12

hollow cylinder

13

baffle

14

spreading disc

15

inlet

Claims (8)

1. A device for preparing a material mixture consisting of a substitute fuel and impurity, having

   - a vertically aligned central feeder (1),

   - a separating device (2) arranged below the central feeder (1),

   - a rotor mill (3), wherein the rotor mill (3) is arranged above the separating device (2) and surrounds the central feeder (1),

   - a flow device (4) for generating an upwardly directed gas flow,

   wherein the material mixture can be introduced into the feeder (1), and after introduced into the feeder (1) sinks down to the separating device (2), wherein the impurity in the separating device (2) is separated from the material mixture at least partially as an impurity fraction, and the material mixture separated from the separated impurities rises with the gas flow to the rotor mill (3), wherein the rising material mixture is comminuted in the rotor mill (3), characterized in that the rotor mill (3) has a multistage design, and a respective separating device (6) is arranged between the stages (5.1, 5.2) of the rotor mill (3), wherein material mixture not retained by the separating device (6) is further comminuted in the following stage (5.2).
2. The device according to claim 1, wherein at least one outlet (7.1, 7.2) is allocated to each stage (5.1, 5.2) of the rotor mill (3).
3. The device according to one of the preceding claims, wherein the separating device (6) comprises at least one sieve between the stages (5.1, 5.2) of the rotor mill (3).
4. The device according to one of the preceding claims, wherein at least the first stage (5.1) of the rotor mill (3) has an annular space (9) that surrounds tools (8a, 8b) of the rotor mill (3), wherein the annular space (9) is preferably separated from the tools (8a, 8b) by a grid arrangement (10).
5. The device according to one of the preceding claims, wherein a cleaning device (11) is allocated to the separating device (6) between the stages (5.1, 5.2) of the rotor mill (3), and can be used to detach the retained material mixture from the separating device (6).
6. The device according to one of the preceding claims, wherein the feeder (1), the separating device (2) and the rotor mill (3) can together be rotationally driven around a vertically aligned axis.
7. The device according to one of the preceding claims, wherein the separating device (2) comprises a rotationally drivable spreading plate (14).
8. The device according to claim 7, wherein the material mixture is spun from the spreading plate (14) into a space surrounding the spreading plate (14), in which the gas flow rises.

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