EP3832205A1 - Exhaust gas aftertreatment device, kit and manufacturing method, and solid fuel combustor - Google Patents

Abstract

The invention relates to an exhaust gas aftertreatment device (2) having at least one flow path (36) which runs from a first end of the exhaust gas aftertreatment device to a second end of the exhaust gas aftertreatment device, the exhaust gas aftertreatment device (2) in at least one section comprising a plurality of disc-shaped elements (3 ) which each form a longitudinal section of the exhaust gas aftertreatment device (2) and which each have at least one recess (35). The invention also relates to a solid fuel firing system (1) with such an exhaust gas aftertreatment device, a kit for manufacturing an exhaust gas aftertreatment device and a method for manufacturing an exhaust gas aftertreatment device.

Description

The invention relates to an exhaust gas aftertreatment device. The invention also relates to a combustion system equipped with such an exhaust gas aftertreatment device, a kit for producing an exhaust gas aftertreatment device and a method for producing an exhaust gas aftertreatment device. Such exhaust gas aftertreatment devices can be used, for example, in solid fuel systems or industrial furnaces.

Boilers for solid fuels which have a cyclone combustion chamber are known from practice. Such a cyclone combustion chamber serves both as a combustion chamber and as a fine dust separator. In this way, on the one hand, an efficient mixing of fuel gas and oxidizing agent can be achieved, so that lower concentrations of pollutants arise during combustion. In addition, a rapid occupancy of a heat exchanger with fine dust or incineration ash is avoided. This results in a better heat exchange and a higher boiler efficiency over a longer operating time, without the operator having to clean the boiler. Compared to metallic or ceramic Pall rings, the cyclone combustion chamber ensures a significant increase in the residence time of the fuel gas and the oxidizing agent in the combustion chamber as well as effective mechanical separation of the dusts.

However, the disadvantage of this known cyclone combustion chamber is the inadequate cleaning effect on the exhaust gases. What is required is a further improved reduction of gaseous pollutants and fine dusts in the exhaust gas with little maintenance effort and little installation space for the exhaust gas aftertreatment device.

Proceeding from the prior art, the invention is therefore based on the object of specifying an exhaust gas aftertreatment device and a method for its production which can be easily adapted to different requirements, in particular different power classes and fuels.

The invention is also based on the object of specifying an exhaust gas aftertreatment device which enables an improved reduction in dust and / or gaseous emissions.

The object is achieved according to the invention by an exhaust gas aftertreatment device according to claim 1, a solid fuel firing system according to claim 10, a kit according to claim 12 and a method according to claim 14. Advantageous further developments of the invention can be found in the subclaims.

According to the invention, according to one embodiment, a firing device is proposed to which a solid or liquid fuel can be fed. The fuel can in particular be a renewable raw material, for example split logs. The fuel is converted with an oxidizing agent when the furnace is in operation. In one embodiment of the invention, the resulting exhaust gas can be fed directly to the proposed exhaust gas aftertreatment device.

In other embodiments, the firing device has an optional cyclone combustion chamber to which a pyrolysis gas and an oxidizing agent can be supplied, which is produced during the pyrolysis of the fuel. Inside the cyclone combustion chamber, the pyrolysis gas is reacted exothermically with the oxidizing agent, so that heat is released. This heat can then be given off to a heat exchanger in order to heat a heat transfer medium in this way. The heat transfer medium can be used to transport heat to a heat consumer. The heat consumer can, for example, be the room heating of a building. In other embodiments of the invention, the heat can be used for drying processes in industrial production or agriculture.

The oxidizing agent supplied to the cyclone combustion chamber can, in some embodiments of the invention, be or contain ambient air. In some embodiments, the oxidizer can _{include ozone (O 3} ) or oxygen radicals (O). The pyrolysis gas can be obtained, for example, from the pyrolysis of a solid fuel, for example logs, wood pellets, agricultural production waste, animal manure, organic waste materials or other media not mentioned here. By pyrolysis of the media mentioned in a low-oxygen atmosphere, a flammable pyrolysis gas is obtained which in particular contains or consists of carbon, carbon monoxide, hydrogen and / or hydrocarbons.

The pyrolysis gas and oxidizer are fed to the cyclone combustion chamber at one end. The shape of the cyclone combustion chamber can cause turbulence, which leads to intensive mixing of the pyrolysis gas and the oxidizing agent. In this way, it can be avoided that a high concentration of pollutants is created due to incomplete oxidation during combustion. The turbulence that occurs in the cyclone combustion chamber can still cause that fine dust, especially soot, is finely dispersed and thus oxidized. Alternatively or in addition, fine dust and ash can be deposited on the walls of the cyclone combustion chamber so that they can be easily removed during maintenance or replacement of the cyclone combustion chamber and do not contaminate subsequent components of a combustion system.

According to the invention, it is now proposed that exhaust gas exiting the cyclone combustion chamber or the exhaust gas resulting from the direct combustion of the fuel be fed to an exhaust gas aftertreatment device, which enables a further reduction in gaseous pollutants and / or fine dusts. The exhaust gas aftertreatment device contains a flow path which, when the exhaust gas aftertreatment device is in operation, moves the exhaust gas from a first end of the exhaust gas aftertreatment device to a second end of the exhaust gas aftertreatment device. direction is flowed through. The exhaust gas aftertreatment device is composed in at least one longitudinal section of a plurality of disk-shaped elements which each form a longitudinal section of the exhaust gas aftertreatment device and which each have at least one recess. The disk-shaped elements can be present in different shapes and sizes, so that different exhaust gas aftertreatment devices can be easily assembled by stacking a certain number of elements and / or by selecting elements with different recesses and / or by choosing the relative orientation of the disk-shaped elements to one another. At the same time, storage is greatly simplified, since a smaller number of different disc-shaped elements can lead to a large number of different exhaust gas aftertreatment devices for different applications. The recess arranged in the disk-shaped elements can be identical in all disk-shaped elements. Provided the recess at least is arranged partially eccentrically in the disk-shaped elements, a non-straight flow path through the exhaust gas aftertreatment device can be implemented by rotating the disk-shaped elements or baffles can be introduced into the flow path. In some embodiments of the invention, the recesses and the orientation can be identical, so that the cross section does not change over the length of the exhaust gas aftertreatment device. In other embodiments of the invention, smaller recesses can be arranged in the disk-shaped elements at one end of the exhaust gas aftertreatment device than at the other end of the exhaust gas aftertreatment device. As a result, the cross section can be designed to be variable, in particular continuously increasing or continuously decreasing.

In some embodiments of the invention, the recess can be designed in such a way that, starting from the center point of the disk-shaped element, an open surface area is present at a predefinable radius at a first angle and a closed surface area is present at a second angle. In polar coordinates, open and closed surface areas alternate depending on the angle coordinate with a constant radius. This feature has the effect that by changing the orientation of the disk-shaped elements within the stack forming the exhaust gas aftertreatment device, non-linear, for example helical or coiled flow paths can be implemented in a simple manner if the recesses of the disk-shaped elements are not positioned exactly one above the other, but around one predeterminable angular range offset. Microturbulences can occur at the stages within the flow path that are created in this way, which can improve the mixing of the exhaust gas and / or the fine dust separation and / or the fine dust agglomeration.

In some embodiments of the invention, starting from the center point of the disk-shaped element, the recess can have at least one partial surface which extends radially outward and which has an opening angle of approximately 10 ° to approximately 50 °. Such recesses, designed in the manner of a pie slice, can also be at least partially relocated by subsequent disk-shaped elements, so that the surface of a flow channel cannot be linear, for example oscillating or helical or coiled. Such a flow channel can contribute to the additional formation of turbulence, so that the mixing of pyrolysis gas and oxidizing agent is improved.

In some embodiments of the invention, the recess can have an area proportion of approximately 25% to approximately 50% of the total area of the disk-shaped element. This enables, on the one hand, a compact design and, on the other hand, a sufficient internal cross-section of the exhaust gas aftertreatment device.

In some embodiments of the invention, adjacent disk-shaped elements from the plurality of disk-shaped elements can be arranged rotated relative to one another by a predeterminable angle. In some embodiments of the invention, the predeterminable angle can be between approximately 5 ° and approximately 30 ° or between approximately 10 ° and approximately 25 °. As already stated, such an embodiment leads to a non-linear flow path within the exhaust gas aftertreatment device, which contributes to a longer dwell time of the pyrolysis gas and the oxidizing agent. The longer dwell time prevents high concentrations of pollutants from occurring during combustion due to only partial oxidation.

In some embodiments of the invention, the disk-shaped elements can have an outer contour which is round. The disk-shaped elements thus have an approximately cylindrical outer shape. As a result, the disk-shaped elements can be stacked on top of one another in a simple manner at different angular orientations without the outer contour deviating from a cylindrical shape. This facilitates the installation of the exhaust gas aftertreatment device in a device, in particular in a solid fuel firing system.

In other embodiments of the invention, the disk-shaped elements can have an outer contour which is polygonal. In some embodiments of the invention, a polygonal outer contour can be octagonal, hexagonal or square, in particular square. As a result, the exhaust gas aftertreatment device has a cuboid outer contour, which allows simple installation in a device, for example a solid fuel firing system. In addition, errors during assembly are avoided, since the orientation of the disk-shaped elements is fixed by their outer contour. In this case, the recesses in the disk-shaped elements can be oriented differently relative to the outer contour. The disk-shaped elements can be provided with a consecutive numbering so that an exhaust gas aftertreatment device with the desired internal cross-section in shape and diameter is obtained by simply stacking them on top of one another in the correct order. This avoids assembly errors, such as those that can arise when stacking cylindrical elements.

In some embodiments of the invention, the disk-shaped elements can contain at least one connecting element. Such a connecting element can, for example, be a pin or contain such a pin which engages in an associated bore of an adjacent disk-shaped element. Such a connector can simplify assembly, increase the mechanical stability of the exhaust gas aftertreatment device and avoid assembly errors.

In some embodiments of the invention, the surface area of the recesses of the disk-shaped elements can increase from the first end of the exhaust gas aftertreatment device to the second end of the exhaust gas aftertreatment device. This enables the production of an exhaust gas aftertreatment device which has an increasing cross-section from the first end to the second end, thereby taking into account the increasing amount of gas that increases with the conversion. In some embodiments of the invention, the exhaust gas aftertreatment device can have an increasing cross section in the manner of a Lavalle nozzle, so that the flow velocity increases from the first end to the second end.

In some embodiments of the invention, the recesses of the disk-shaped elements can form a coiled path from the first end of the exhaust gas aftertreatment device to the second end of the exhaust gas aftertreatment device. As a result, the path length of the pyrolysis gas within the exhaust gas aftertreatment device can be increased with unchanged external dimensions, which can lead to an improved conversion of the pyrolysis gas due to longer residence times. This can reduce the pollutants and increase the heat yield.

In some embodiments of the invention, the disk-shaped elements can consist of a metal or an alloy. These materials are characterized by a comparatively large specific heat capacity and high thermal and mechanical stability. This ensures a strong heat radiation and heat emission during operation, so that the oxidation of the pyrolysis gas can be guaranteed.

In some embodiments of the invention, the disc-shaped elements can be joined in a materially bonded manner, for example by sintering and / or welding and / or gluing.

In some embodiments of the invention, the disk-shaped elements can consist of an inorganic, non-metallic material. An inorganic non-metallic material can in particular contain or consist of a ceramic, for example an oxide ceramic or a carbide or a nitride or an oxynitride. In some embodiments of the invention, silicon dioxide and / or aluminum oxide and / or magnesium oxide and / or calcium oxide and / or zirconium oxide and / or chromium oxide and / or silicon carbide can be used. In some embodiments of the invention, these materials can have a catalytic effect, so that the combustion temperature for fine dust, in particular soot and / or gaseous constituents of the pyrolysis gas, drops. This means that the pollutant content can be kept low even at low firing temperatures. In some embodiments of the invention, the surface of a ceramic can be porous or have adhesive properties, so that effective binding of fine dust is made possible.

In some embodiments of the invention, organic fine dust can be bound to the walls of the exhaust gas aftertreatment device in operating states with a low exhaust gas temperature and oxidized in operating states with a high exhaust gas temperature. In this context, a low exhaust gas temperature is understood to mean an exhaust gas temperature below 450 ° C or below 500 ° C. In this context, a high exhaust gas temperature is understood to mean an exhaust gas temperature above 500 ° C or above 520 ° C.

In some embodiments of the invention, inorganic fine dust can form on the walls of the exhaust gas aftertreatment device be bound or form agglomerates. These agglomerates can form closed layers or crusts which, when a certain layer thickness is exceeded, detach from the walls of the exhaust gas aftertreatment device due to internal stresses. These can then be removed via an inspection opening or via the combustion chamber or ash pan.

In some embodiments of the invention, the disk-shaped elements can each have between one and about 30 recesses. In some embodiments of the invention, a recess can be arranged in the disk-shaped element in such a way that the center points of the disk-shaped element and the recess coincide. In other embodiments of the invention, several disc-shaped elements can be designed so that they each have an identical number of recesses, the center points of which are arranged at the same points of the respective discs and which have a different angular orientation in different discs.

In some embodiments of the invention, the exhaust gas aftertreatment device and / or a solid fuel firing system equipped with it can contain at least one spray electrode which is set up to generate an electric field in at least one section. When the solid fuel firing system is in operation, the electric field can be selected below the breakdown field strength and, for example, be less than 1 kV / mm or less than 0.7 kV / mm or less than 0.6 kV / mm. In some embodiments of the invention, the electric field can be greater than about 0.4 kV / mm. The converted electrical power can be between about 15 W and about 35 W. By installing the spray electrode in the exhaust gas aftertreatment device, the effect of soot or tar deposits is at least reduced, so that the maintenance interval can be extended.

The electric field causes an agglomeration of fine dust, so that the then larger dust particles can be retained more easily on the walls of the exhaust gas aftertreatment device or an optional filter element. In addition, the electric field can generate oxygen radicals and / or ozone, so that the oxidation of organic constituents of the exhaust gas or the dust that occurs can take place more easily, in particular at lower temperatures.

In some embodiments of the invention, the exhaust gas aftertreatment device and / or a solid fuel firing system equipped with it can contain at least one electrode or a pair of electrodes which is set up to enable a dielectically impeded discharge (DBE). For this purpose, a dielectric can be arranged in the discharge gap, which in some embodiments of the invention is selected from a ceramic or porcelain. As a result, ozone and / or atomic oxygen can be generated from ambient air with high efficiency.

In some embodiments of the invention, the discharge can be designed either in the form of many filaments or as a homogeneous discharge, so that the discharge extends over the entire discharge volume or a large part of the volume. The DBE has the effect that approximately only electrons are accelerated, since the discharge duration is so short that the heavier ions, due to their inertia, only absorb a small amount of momentum. The discharge ceases as soon as the applied electric field is compensated by the electric charge accumulated in front of the dielectric. The duration of a discharge can be in the range of a few nanoseconds.

To generate a DBE, pulsed excitation or the pulsed application of an operating voltage to the at least one electrode is advantageous. The DBE can use unipolar or bipolar pulses with pulse durations of approximately 1 to approximately 10 microseconds or operated from about 20 ns to about 900 ns. In some embodiments, the amplitude of the operating voltage can be between about 2 kV and about 10 kV. The pulse / pause ratio can be less than about 20% or less than about 15% or less than about 10%.

In some embodiments of the invention, the disk-shaped elements of the exhaust gas aftertreatment device can consist of a material with a heat capacity of approximately 0.55 kJ / (kg · K) to approximately 1.2 kJ / (kg · K). In some embodiments of the invention, the exhaust gas aftertreatment device can have a mass of about 15 kg to about 50 kg or from about 20 kg to about 40 kg. This makes it possible to store an amount of heat at temperatures between 490 ° C and 520 ° C which at least corresponds to the heat released when about 0.75 kg to about 1.1 kg of wood is burned. This allows a consistently low-pollutant combustion, even if the combustion temperature drops temporarily.

In some embodiments of the invention, the length of the exhaust gas aftertreatment device or the length of the coiled path can be selected such that the flow time of the pyrolysis gas is at least between approximately 1.2 s and approximately 1.8 s. This enables efficient exhaust gas aftertreatment with good efficiency and low pollutant emissions.

• Fig. 1 eine Feststofffeuerungsanlage gemäß einer ersten Ausführungsform der vorliegenden Erfindung.
• Fig. 2 zeigt eine Abgasnachbehandlungseinrichtung gemäß einer ersten Ausführungsform in einer ersten Ansicht.
• Fig. 3 zeigt die Abgasnachbehandlungseinrichtung gemäß der ersten Ausführungsform in einer zweiten Ansicht.
• Fig. 4 zeigt einen Schnitt durch eine Abgasnachbehandlungseinrichtung gemäß der ersten Ausführungsform.
• Fig. 5 zeigt die Abgasnachbehandlungseinrichtung gemäß der ersten Ausführungsform in einer dritten Ansicht.
• Fig. 6 verdeutlich den Strömungspfad innerhalb der Abgasnachbehandlungseinrichtung gemäß der ersten Ausführungsform.
• Fig. 7 zeigt ein scheibenförmiges Element gemäß einer ersten Ausführungsform in einer ersten Ansicht.
• Fig. 8 zeigt das scheibenförmige Element gemäß der ersten Ausführungsform in einer zweiten Ansicht.
• Fig. 9 zeigt ein scheibenförmiges Element gemäß einer zweiten Ausführungsform.
• Fig. 10 zeigt ein scheibenförmiges Element gemäß einer dritten Ausführungsform.
• Fig. 11 zeigt eine Feststofffeuerungsanlage gemäß einer zweiten Ausführungsform der vorliegenden Erfindung.
• Fig. 12 zeigt eine Feststofffeuerungsanlage gemäß einer dritten Ausführungsform der vorliegenden Erfindung.
• Fig. 13 zeigt eine genauere Ansicht eines Bauteils der Feststofffeuerungsanlage gemäß der dritten Ausführungsform der vorliegenden Erfindung.
• Fig. 14 zeigt einen Abschnitt einer Abgasnachbehandlungseinrichtung gemäß einer zweiten Ausführungsform.
• Fig. 15 zeigt einen Abschnitt einer Abgasnachbehandlungseinrichtung gemäß einer dritten Ausführungsform

The invention is to be explained in more detail below with reference to figures, without restricting the general inventive concept. It shows

• Fig. 1 a solid fuel furnace according to a first embodiment of the present invention.
• Fig. 2 shows an exhaust gas aftertreatment device according to a first embodiment in a first view.
• Fig. 3 shows the exhaust gas aftertreatment device according to the first embodiment in a second view.
• Fig. 4 shows a section through an exhaust gas aftertreatment device according to the first embodiment.
• Fig. 5 shows the exhaust gas aftertreatment device according to the first embodiment in a third view.
• Fig. 6 illustrates the flow path within the exhaust gas aftertreatment device according to the first embodiment.
• Fig. 7 shows a disk-shaped element according to a first embodiment in a first view.
• Fig. 8 shows the disk-shaped element according to the first embodiment in a second view.
• Fig. 9 shows a disk-shaped element according to a second embodiment.
• Fig. 10 shows a disk-shaped element according to a third embodiment.
• Fig. 11 Fig. 3 shows a solid fuel furnace according to a second embodiment of the present invention.
• Fig. 12 Fig. 13 shows a solid fuel furnace according to a third embodiment of the present invention.
• Fig. 13 shows a more detailed view of a component of the solid fuel combustion system according to the third embodiment of the present invention.
• Fig. 14 shows a section of an exhaust gas aftertreatment device according to a second embodiment.
• Fig. 15 shows a section of an exhaust gas aftertreatment device according to a third embodiment

Based on Fig. 1 a solid fuel furnace according to the present invention is explained in more detail.

The solid fuel firing system 1 contains a housing 10 which is made of a fire-resistant material, for example a metal or an alloy. In some cases, the walls of the housing 10 can also have multiple layers and contain thermal insulation, for example.

The housing 10 is divided into a first chamber 11, a second chamber 12 and a third chamber 13 by inner walls. In the bottom area of the respective chambers there are assigned ash removal systems 111, 121 and 131, each in the form of a screw conveyor. However, these are optional and can also be omitted in other embodiments of the invention.

The first chamber 11 is designed as a pyrolysis chamber. In the first chamber 11 there is therefore a fire grate 112 as well as a feeder 15 through which solid fuel, such as wood pellets, can be supplied. In other embodiments of the invention, split logs, biomass or any other solid fuel can of course also be used. In these cases, the delivery submission 15 can take on a different design or can be omitted.

The fuel supplied is pyrolysed in the first chamber 11, a pyrolysis gas being produced. The pyrolysis gas can contain or consist of carbon and / or carbon monoxide and / or hydrogen and / or hydrocarbons. This pyrolysis gas is passed through the gas inlet 115 into the second chamber.

The second chamber 12 contains a cyclone combustion chamber 125 and an exhaust gas aftertreatment device 2. In the cyclone combustion chamber 125, the pyrolysis gas is reacted with an oxidizing agent, in particular ambient air. The resulting exhaust gas is fed into the exhaust gas aftertreatment device 2. After passing through the exhaust gas aftertreatment device 2, the exhaust gas cleaned in this way is partially returned to the first chamber 11 via an exhaust gas line 122, where it is used for pyrolysis of the fuel. Another part of the exhaust gas is passed into the third chamber 13, which contains a heat exchanger 132. There, the heat contained in the exhaust gas is transferred to a liquid or gaseous heat transfer medium and transported to the place of use.

An optional induced draft fan 135 is used to maintain the flow of exhaust gas through the second chamber 12 and the third chamber 13.

It should be noted that the solid fuel furnace 1 shown is only to be understood as an example. In other embodiments of the invention, the solid fuel firing system can also have a different design, so that some of the components mentioned can be designed differently or are also omitted. The invention does not teach the use of a particular solid fuel furnace as a principle of solution. Rather, the invention relates primarily to the exhaust gas aftertreatment device 2, which in exemplary embodiments below with reference to FIG Figures 2 to 6 and 14 to 15 is explained in more detail.

Fig. 2 shows an axonometric representation of the exhaust gas aftertreatment device 2, Fig. 3 shows a view and Fig. 5 shows a top view. In Fig. 4 FIG. 13 shows a section through the exhaust gas aftertreatment device along the line AA, as shown in FIG Fig. 3 can be seen. Fig. 6 shows an axonometric sectional view, the coiled Path through the exhaust aftertreatment device is highlighted.

As can be seen from the figures, the exhaust gas aftertreatment device 2 is composed of a plurality of disc-shaped elements 3. In the illustrated embodiment, there are 20 disc-shaped elements. In other embodiments of the invention, the number of disk-shaped elements 3 can be greater or fewer and, for example, between approximately 5 and approximately 100 or between approximately 10 and approximately 50 or between approximately 15 and approximately 40 or between approximately 5 and approximately 25.

The disk-shaped elements can have a thickness of about 10 mm to about 100 mm or from about 10 mm to about 50 mm. In some embodiments of the invention, the diameter of the circular elements shown in the exemplary embodiment shown can be between approximately 70 mm and approximately 500 mm or between approximately 100 mm and approximately 400 mm.

How out Fig. 2 and Fig. 5 As can be seen, each disc-shaped element 3 contains a recess 35 which is roughly in the shape of a four-leaf clover, that is, starting from an approximately circular central area located in the center 33 of the disc-shaped element, the recess 35 extends in four sub-areas which are equidistant in the radial direction radially outwards. If the recess is described in polar coordinates with a coordinate origin in the center 33 of the disk-shaped element, there are both open surface areas or partial surfaces of the recess 35 and closed surface areas of the disk-shaped element 3 under a predeterminable radius r with different values of the angle coordinates.

As in the Figures 4, 5 and 6th As can be seen, the disk-shaped elements 3 are placed one on top of the other within the stack forming the exhaust gas aftertreatment device 2 in different orientations. The recess 35 of a disk-shaped element 3 is thus partially covered by a partial area of the disk-shaped element located above it. The recesses 35 of the disk-shaped elements 3 thus form a coiled path 36 from the first end 21 of the exhaust gas aftertreatment device 2 to the second end 22 of the exhaust gas aftertreatment device 2. This can lead to a longer dwell time of the pyrolysis gas, so that an improved reaction with the oxidizing agent takes place. Furthermore, the flow can be accelerated to a circular path through the shape of the combustion chamber, so that fine dust, soot and ash particles are carried to the outside and separated inside the exhaust gas aftertreatment device 2. This can prevent or reduce clogging of the heat exchanger in a solid fuel plant.

In the exemplary embodiment shown, the cross section of the flow path within the exhaust gas aftertreatment device 2 is constant from the first end 21 and the second end 22. This means that the disk-shaped elements 3 all have an identical shape and size. In other embodiments of the invention, different disk-shaped elements 3 can be used, so that the cross section of the flow path 36 is variable from the first end 21 to the second end 22. For example, the cross section can increase from the first end 21 to the second end 22.

Based on Fig. 7 the shape of the recess 35 is explained again. The description of the recess 35 takes place in polar coordinates, the coordinate origin being selected at the center point 33 of the disk-shaped element 3. In the case of a predeterminable radius, there is thus a first one Partial surface 31 at a predeterminable angle α in the interior of the recess 35. This means that the first partial surface 31 is free of material. At a second angle β, which is approximately 90 ° in the illustrated embodiment, second partial surfaces 32 are formed, which are closed.

This based on Fig. 7 The principle explained can be continued for different angles and radii, so that the in Fig. 7 Shown shape of the recess can be described. It is essential for the described first embodiment of the invention that the recess 35 is arranged at least partially eccentrically in the disk-shaped element 3, so that the recesses 35 come to lie offset one above the other due to the different angular orientation of the disk-shaped element 3 and the in Fig. 6 Form illustrated coiled path 36. The specific shape and size of the recess 35 can of course also be selected differently in other embodiments of the invention.

This fact is again based on the Fig. 8 explained, which represents the recess 35 which, starting from the center point 33 of the disk-shaped element 3, has at least one partial surface 34 which extends radially outward and has an opening angle γ of approximately 10 ° to approximately 50 °. In the Fig. 8 The boundary line 341 shown and the further edges of the recess 35 or the radially outwardly extending partial surface 34 do not necessarily have to be as shown in FIG Fig. 8 shown, run in a straight line. Other embodiments of the invention can also be concavely or convexly curved boundary lines.

Based on the Figures 2 to 8 The disk-shaped elements 3 shown have an approximately circular outer contour 39. This makes it possible, depending on the length of the exhaust gas aftertreatment device 2, to obtain the desired Number of disc-shaped elements to be stacked on top of each other in any angular relationship. Each of the disk-shaped elements 3 can thus be placed about 1 ° to about 30 ° or about 5 ° to about 15 ° relative to the preceding disk-shaped element 3 in order to form the exhaust gas aftertreatment device 2.

Based on Figures 9 and 10 disk-shaped elements 3 are shown according to a second embodiment. These have a square outer contour 39. In other embodiments of the invention, the outer contour can of course also have a different polygonal shape.

As already explained with reference to the above embodiment, the disk-shaped elements according to FIG Figures 9 and 10 a recess 35 which is aligned point-symmetrically to the center point 33. The ones in the Figures 9 and 10 However, the illustrated embodiments of the disk-shaped element 3 have recesses 35 which, although they have an identical shape and size, but assume a different orientation relative to the outer contour 39. This makes it possible, when stacking the disk-shaped elements 3 to set up an exhaust gas aftertreatment device 2, to align the disk-shaped elements 3 along their outer contours. Due to the different orientation of the recesses 35, they are nevertheless arranged within the exhaust gas aftertreatment device 2 rotated by a certain angle to one another even with the same orientation of the outer contour 39, so that the Fig. 6 apparent winding path 36 results.

For the construction of larger exhaust gas aftertreatment devices 2, several different disc-shaped elements 3 can also be used, in which the recesses 35 are arranged by about 1 ° to about 30 ° or by about 5 ° to about 15 ° relative to the polygonal outer contour 39. The The invention does not teach the use of exactly 2 different disc-shaped elements 3 as a solution principle.

Based on Figure 11 a solid fuel furnace according to a second embodiment of the present invention will be explained. The same components of the invention are provided with the same reference symbols, so that the following description is limited to the essential differences.

The solid fuel firing system according to the second embodiment also contains a housing 10, which can be made of a fire-resistant material, such as sheet steel, for example. Partial areas of the wall can be made double-walled, the space in between can be insulated by air flow and / or insulating material such as mineral wool or vermiculite.

As the sectional view of the second embodiment shows, the inner walls present in the first embodiment, which divide the housing into a plurality of chambers, are omitted in the second embodiment. Rather, the only chamber of the housing 10 is designed as a combustion chamber, which is accessible through a combustion chamber door 101. There fuel can be placed on a fire grate 112. The air required for combustion can either be supplied via air supply lines (not shown) or from below through the grate 112. The resulting ash falls through the grate 112 into the ash pan 113 below.

The exhaust gases produced when the fuel is burned up, driven by convection, flow through the exhaust gas aftertreatment device 2 before they exit the flue gas opening 103. Within the exhaust gas aftertreatment device 2, oxidizable gases are post-oxidized in the flue gas, so that they are not released into the environment as air pollutants. In addition, organic fine dust can be post-oxidized in the exhaust gas aftertreatment device 2 so that it does not get into the environment as fine dust. Alternatively or additionally, fine dust can be agglomerated to coarse dust in at least some operating states. The coarse dust can either be deposited on the material of the exhaust gas aftertreatment device 2 until it can be oxidized at sufficiently high temperatures. Alternatively or additionally, inorganic dusts can form layers or crusts on the surfaces of the exhaust gas aftertreatment device 2, which flake off due to temperature fluctuations or due to mechanical stresses induced by the layer thickness and fall into the ash pan 113. In this case, the dust can be disposed of together with the remaining combustion residues without them being released into the atmosphere.

The exhaust gas aftertreatment device 2 has a polygonal, in particular rectangular or square, outline. In the exhaust gas aftertreatment device there are a plurality of openings which each form a coiled flow path, as above with reference to FIG Figures 2 to 10 explained. Examples of exhaust gas aftertreatment device 2, which contain a plurality of flow paths running in parallel, are described below with reference to FIG Figures 14 and 15 explained in more detail.

Figure 11 also shows an optional spray electrode 45, which is connected to a high-voltage supply 4. This function is also explained below using the Figure 15 explained in more detail.

Based on Figures 12 and 13 a solid fuel furnace according to a third embodiment of the present invention will be explained. It shows Figure 12 a sectional view the entire solid fuel furnace and Figure 13 shows a component of the solid fuel combustion system. In this case too, the same reference symbols denote the same components of the invention, so that the following description can be limited to the essential differences.

As already mentioned above with reference to Figure 1 explained, the housing 10 is divided by a wall into a first chamber 11 and a second chamber 12. The first chamber 11 is designed as a pyrolysis chamber. In the first chamber 11 there is therefore a fire grate 112 on which an organic fuel can be pyrolyzed. The resulting pyrolysis gas enters the cyclone combustion chamber 125, which is located in the second chamber 12, through the gas inlet 115. The pyrolysis gas is reacted with an oxidizing agent in the cyclone combustion chamber 125. The resulting exhaust gas is then passed through the exhaust gas aftertreatment device 2 before the cleaned exhaust gas is discharged into the environment through the flue gas connection 103.

The exhaust gas aftertreatment device 2 has an essentially cylindrical basic shape and is composed of a plurality of disc-shaped elements. In the cylindrical basic shape of each disk-shaped element 3 there are several openings 35, so that a plurality of parallel flow paths is formed. As a result, the exhaust gas back pressure of the exhaust gas aftertreatment device can be reduced and / or the flue gas throughput can increase.

How Figure 13 shows, the second chamber 12 furthermore contains an optional feed opening 123, which is connected to an ozone generator 124 known per se. In this way, ozone and / or oxygen radicals can be fed to the exhaust gas flow emerging from the cyclone combustion chamber 125, which improve or enable the conversion of the pollutants contained in the exhaust gas within the exhaust gas aftertreatment device. In particular, by adding Ozone or oxygen radicals cause the oxidation of pollutants and fine dust to take place at a lower temperature.

Also the Figures 12 and 13 show an optional high-voltage device 4 which, with at least one spray electrode, exposes the exhaust gas flow to an electrical field, at least in sections. This electrical field can promote the accumulation of unburned fine dust on the walls of the flow paths of the exhaust gas aftertreatment device 2 and / or support the agglomeration of fine dust, so that the fine dust becomes a coarse dust, which either sinks to the ground against the flue gas flow and removes it from the bottom of the cyclone combustion chamber 125 can be. Alternatively or additionally, the dusts can be stored in the exhaust gas aftertreatment device and post-oxidized at a later point in time.

The exhaust gas aftertreatment device 2 can have a mass of approximately 20 kg to approximately 40 kg. The material of the disk-shaped elements 3 forming the exhaust gas aftertreatment device 2 can have a heat capacity of approximately 0.55 kJ / (kg · K) to approximately 1.2 kJ / (kg · K). In this way, an amount of heat can be stored in the exhaust gas aftertreatment device at a temperature of around 500 ° C. which corresponds to the amount of heat that is released during the combustion of around 0.7 kg to around 1 kg of wood. This amount of heat is sufficient to ensure the exhaust gas aftertreatment of the resulting flue gases when the exhaust gas temperature drops temporarily, for example when adding fuel. This effect is based in particular on the fact that heat is given off to the flue gases in the exhaust gas aftertreatment device 2, which are colder in these operating phases, until they have reached a temperature of more than about 500 ° C. or more than about 550 ° C., which is favorable for minimizing pollutants. The length of the exhaust gas aftertreatment device 2 or of the flow paths 36 formed in the exhaust gas aftertreatment device 2 is selected so that the flow time of an exhaust gas is at least between about 1.2 seconds and about 1.8 seconds. This time is sufficient to enable efficient exhaust gas aftertreatment and to minimize pollutant emissions. At the same time, the installation space required for this is sufficiently small to use the exhaust gas aftertreatment device according to the invention in common small fire systems.

Figure 14 shows a longitudinal section of an exhaust gas aftertreatment device according to a second embodiment of the invention. In contrast to the Figures 2 to 10 As shown in the first embodiment of the invention, the second embodiment differs in particular in that each disk-shaped element 3 has a plurality of openings. In Figure 14 the openings 35a, 35b and 35c are designated by way of example with reference numerals. In particular, the number of openings 35 can be between about 2 and about 30 in some embodiments of the invention.

In some embodiments of the invention, the openings 35 can be arranged at the same locations of different disk-shaped elements 3, but the openings in different disk-shaped elements 3 are rotated to one another by a predeterminable angular amount, as shown in FIG Figures 9 and 10 has been explained for a single opening. Thus, when the disk-shaped elements 3 are stacked one on top of the other, coiled paths 36 are again formed. Furthermore, at the boundaries of adjacent disk-shaped elements 3, edges or steps arise in the coiled path 36, which create microturbulence. On the one hand, this turbulence leads to the exhaust gas being mixed with the oxidizing agent, so that an efficient post-oxidation of gaseous or dusty pollutants can take place. In addition, the microturbulence contributes to the deposition of non-oxidizable dust on the walls, until it either emerges as an inorganic crust from the exhaust gas aftertreatment device 2 fall out or sufficient conditions, in particular sufficiently high temperatures, exist for their oxidation.

Figure 14 shows only eight disc-shaped elements 3 by way of example Figures 1 and 11 to 13 As can be seen, the exhaust gas aftertreatment device according to the invention can of course also achieve a greater longitudinal extent, so that the desired longitudinal extent or the desired total mass is achieved.

Based on Figure 15 a third embodiment of the present invention is explained in more detail. The third embodiment differs from the first and second embodiments described above in particular in the presence of a spray electrode 45. The spray electrode 45 consists of a metal or an alloy. The spray electrode has approximately the shape of the disk-shaped elements 3. In some embodiments of the invention, the outer contour or the entire surface area of the spray electrode 45 can be smaller than the outer contour of the adjacent disk-shaped elements 3. The disk-shaped elements 3 can have a recess which receives the spray electrode 45. As a result, the spray electrode can be completely surrounded by the disk-shaped elements 3, so that it is protected from accidental contact. At least the disk-shaped elements 3 directly adjoining the spray electrode 45 can be made of an electrically insulating material, for example a ceramic. Otherwise, the spray electrode 45 has identical or similar openings 35a and 35b as the disk-shaped elements 3 above and below, so that the paths 36 remain continuous.

The spray electrode 45 is connected to a high-voltage generator 43 via an electrical conductor 41. The high voltage generator 43 can draw a primary voltage by means of a mains cable or battery-operated or through a thermal generator and emit a high voltage at its output, which is, for example, more than 500 V or more than 1 kV or more than 5 kV or more than 10 kV or more than 20 kV. The high voltage can be selected in such a way that electrical field strengths below the breakdown voltage are generated at the spray electrode 45. In some embodiments of the invention, the field strength at the spray electrode 45 can be less than, for example, 1 kV / mm or less than 0.7 kV / mm or less than 0.6 kV / mm. However, the voltage can be selected to be so high that the electric field at the spray electrode 45 is greater than approximately 0.4 kV / mm.

The electrical conductor 41 can be protected from contact by electrical insulation 42. The insulation 42 can have ribs in a manner known per se in order to increase the path length for creep stresses and thereby improve the insulation. The insulation 42 can be guided in a tube 44 made of a plastic or a ceramic in order to protect the user of the small fire system equipped with the device from touching the high voltage.

When the high-voltage source 43 is in operation, an electric field is thus applied to the spray electrode 45. The flue gases flowing in the coiled path 36 thus pass through at least one longitudinal section in the exhaust gas aftertreatment device, in which they are exposed to an electrical field. The electric field can support the agglomeration of fine dust and thus the conversion of fine dust into coarse dust. In addition, the electrically charged fine dust can electrostatically adhere to the walls of the coiled paths 36 and thereby be filtered from the exhaust gas flow. This measure can thus the effectiveness of the exhaust gas aftertreatment device according to the invention can be further increased.

In some embodiments of the invention, the spray electrode can be designed to generate a dielectrically impeded discharge. As a result, ozone and / or atomic oxygen can be generated from ambient air with high efficiency, so that pollutants can be efficiently oxidized.

Of course, the invention is not limited to the embodiments shown. The above description is therefore not to be regarded as restrictive, but rather as explanatory. The following claims are to be understood in such a way that a named feature is present in at least one embodiment of the invention. This does not exclude the presence of further features. Insofar as the claims and the above description define “first” and “second” embodiments, this designation serves to distinguish between two similar embodiments without defining an order of precedence.

Claims (15)

Exhaust gas aftertreatment device (2), having at least one flow path (36) which runs from a first end of the exhaust gas aftertreatment device to a second end of the exhaust gas aftertreatment device, characterized in that the exhaust gas aftertreatment device (2) consists of a plurality of disc-shaped elements (3) in at least one section. is composed, which each form a longitudinal section of the exhaust gas aftertreatment device (2) and which each have at least one recess (35). Exhaust gas aftertreatment device according to Claim 1, characterized in that the at least one recess (35) is designed in such a way that, starting from the center point (33) of the recess (35) at a predeterminable radius (r) at a first angle (α), an open surface area ( 31) is present and a closed surface area (32) is present at a second angle (β) and / or that the recess (35), starting from the center point (33) of the recess (35), has at least one partial surface (34) which is extends radially outward and has an opening angle (γ) of approximately 10 ° to approximately 50 ° and / or
that the recess (35) has an area proportion of about 25% to about 50% of the total area of the disk-shaped element (3). Exhaust gas aftertreatment device according to one of Claims 1 or 2, characterized in that the disc-shaped elements (3) each have between one and approximately 30 recesses (35) and / or
that adjacent disc-shaped elements (3) from the A plurality of disc-shaped elements (3) are arranged rotated by a predeterminable angle to one another. Exhaust gas aftertreatment device according to one of Claims 1 to 3, characterized in that the disc-shaped elements (3) have an outer contour (39) which is or is polygonal or round
that the disc-shaped elements (3) have an outer contour (39) which is rectangular, in particular square. Exhaust gas aftertreatment device according to one of Claims 1 to 4, characterized in that the area of the recesses (35) of the disc-shaped elements (3) increases from the first end (21) of the exhaust gas aftertreatment device (2) to the second end (22) of the exhaust gas aftertreatment device (2) and /or
that the recesses (35) of the disc-shaped elements (3) form a coiled path (36) from the first end (21) of the exhaust gas aftertreatment device (2) to the second end (22) of the exhaust gas aftertreatment device (2) and / or
that the exhaust gas aftertreatment device has a mass of about 15 kg to about 50 kg or from about 20 kg to about 40 kg. Exhaust gas aftertreatment device according to one of claims 1 to 5, characterized in that the disc-shaped elements (3) consist of a metal or an alloy or an inorganic non-metallic material, in particular a material which contains silicon dioxide and / or aluminum oxide and / or magnesium oxide and / or calcium oxide and / or contains or consists of zirconium oxide and / or chromium oxide and / or silicon carbide and / or
that the disc-shaped elements (3) consist of a material with a heat capacity of about 0.55 kJ / (kg · K) to about 1.2 kJ / (kg · K). Exhaust gas aftertreatment device according to one of claims 1 to 6, characterized in that its length or the length of the coiled path (36) is selected so that the flow time of an exhaust gas is at least between about 1.2 s and about 1.8 s Exhaust gas aftertreatment device according to one of Claims 1 to 7, further comprising at least one spray electrode (45) which is set up to generate an electric field in at least one section. Exhaust gas aftertreatment device according to one of Claims 1 to 8, further comprising at least one spray electrode (45) which is set up to generate a dielectrically impeded discharge. Solids firing system (1) with an exhaust gas aftertreatment device according to one of Claims 1 to 9. Solids firing system according to claim 10, further comprising an ozone generator (124) and a supply opening (123) which are set up _{to supply ozone (O 3} ) and / or oxygen radicals (O) to a combustion air and / or an exhaust gas flow. Kit for producing an exhaust gas aftertreatment device according to one of Claims 1 to 9, containing at least a plurality of disc-shaped elements (3), each of which has a recess (35). Kit according to claim 12, characterized in that the disc-shaped elements (3) have an outer contour (39) which is quadrangular, in particular square, and the respective recess (35) in at least two disc-shaped elements (3) has a different orientation relative to the outer contour . Method for producing an exhaust gas aftertreatment device according to one of Claims 1 to 9, with the following steps: Providing a plurality of disc-shaped elements (3), each of which has at least one recess (35); Stacking the plurality of disc-shaped elements (3) so that they each form a longitudinal section of the exhaust gas aftertreatment device (2). Method according to claim 14, characterized in that the plurality of disk-shaped elements (3) are stacked in such a way that the recesses (35) of the disk-shaped elements (3) from the first end (21) of the exhaust gas aftertreatment device (2) to the second end (22) of the exhaust gas aftertreatment device (2) form a coiled path (36) and / or
that furthermore at least one spray electrode (45) is introduced between the plurality of disc-shaped elements (3).

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