DE202016100904U1 - Filter system for the filtration of a hot raw gas and filter element for such a filter system - Google Patents

Abstract

Filter system (1) for filtering a hot raw gas, such as a combustion and / or process gas, comprising: a primary filter module (2) which is adapted to filter solid particles from a flowing raw gas; and a separate secondary filter module (3) arranged downstream of the primary filter module (2) and in fluid communication with the primary filter module (2) for passing through the prefiltered gas leaving the primary filter module (2), the secondary filter module (3) communicating with at least one catalyst for the catalytic conversion of chemical compounds contained in the flowing raw gas, in particular pollutants is provided, characterized in that the secondary filter module (3) is a safety filter module which is adapted to filter solid particles from the raw gas.

Description

The invention relates to a filter system for filtering a hot raw gas, such as a combustion and / or process gas, comprising a primary filter module, which is designed to filter solid particles from a raw gas flowing through, and a separate secondary filter module, which is arranged downstream of the primary filter module and with the primary filter module is in fluid communication to be flowed through by the primary filter module leaving the prefiltered gas leaving, wherein the secondary filter module is provided with at least one catalyst for the catalytic conversion of chemical compounds contained in the flowing raw gas, in particular pollutants. Moreover, the invention relates to a filter element for use as a secondary filter element in such a filter system.

Process or exhaust gases occur in the most diverse areas of industry but also in everyday life of every human being. There are exhaust fumes from combustion plants, gas turbines, waste incinerators and internal combustion engines, to name just a few examples. Due to environmental, safety and health requirements such process or exhaust gases, often referred to as raw gases, must be cleaned or catalytically treated. As a result of their formation process, such raw gases are often hot gases. For purifying hot raw gases, filter systems are known from the prior art which are both capable of reducing or minimizing toxic pollutants contained in the crude gas and of removing solid particles or dusts from the raw gas. This is important because some pollutants can cause short-term poisoning if inhaled. On the other hand, fines particles in the ambient air can cause cancer in humans in the medium or long term.

From the WO 2006/103040 A1 is a method for the catalytic reduction of nitrogen oxides (NO _x ), inter alia by adding ammonia (NH ₃ ) in the raw gas stream known. In this regard, a catalytic dedusting is described, which can retain both by means of surface filtration solids as well as by means of an integrated catalyst can enable catalytic reactions. In this case, the functions of dust filtration and catalytic reduction are integrated into a single filter module. Here, the catalyst is embedded in a porous wall of the filter module behind a Staubfilterungsoberfläche. However, such a catalytic dedusting is very expensive in operating costs and has low reliability. Because often the catalytic dedusting has to be replaced due to an irreversible clogging with dust particles and not due to exhaustion of the catalyst. In addition, in the event of damage to the catalytic dedusting filter fine particles can pass unhindered on the clean gas side and damage the equipment arranged there.

Alternatively, in the WO 2006/103040 A1 describes a filter system in which the functions of dust filtration and the catalytic reduction of different filter modules are met. Here, the dedusting of the raw gas by means of a non-catalytic primary filter module. The largely dedusted, but still pollutant-containing gas leaves the primary filter module and is passed through a purely catalytic secondary filter module to remove pollutants there. Such a filter system has a low reliability. Because in case of damage to the primary filter module dusty raw gas flows freely through the catalytic secondary filter module, which can be damaged by or at least has a significantly reduced life. Thus, it will also be necessary to replace the relatively expensive catalytic secondary filter module. In addition, the primary filter module downstream, purely catalytic secondary filter module is not able to retain the dust particles, which is why they pass unhindered on the clean gas side of the filter system and can damage the subsequent systems. For example, it may be necessary to switch off a downstream gas turbine to prevent damage to the system.

The invention is therefore based on the object to provide a filter system of the type mentioned, which has an increased availability and reliability while reducing operating costs.

This object is achieved in that the secondary filter module is a safety filter module, which is designed to filter solid particles from the raw gas.

The basic idea of the invention is thus that, in addition to its function as a catalyst, the secondary filter module is suitable for filtering solid particles from the raw gas in the event of a failure of the primary filter module, but operates dust-free in normal operation of the filter system. In this way, it is possible to efficiently prevent solid particles and / or dusts from reaching the clean gas side of the filter system during the operation of the filter system, for example in the event of breakage or other damage to a filter cartridge of the primary filter module. Because of such fine particles, for example, arranged behind the filter system gas turbine can be severely damaged and therefore should be shut down for safety reasons. Generally, from the filter system unintentionally leaking dusts lead to considerable disturbances in the downstream processes or systems. On the other hand, the filter system according to the invention can continue to operate at least for a short time even in the case of damage, in particular if the primary filter module breaks, since the catalytic secondary filter module, in its function as safety filter module, prevents the dust from penetrating the clean gas side. If the secondary filter module is clogged by the collected dust, a gas flow through the secondary filter module is completely interrupted, so that no gas at all, so that no dust can leave the secondary filter module. The secondary filter module is thus completely ineffective. However, this is not critical because conventional filter systems are operated with a plurality, often several hundred arrangements of primary filter element and downstream secondary filter element, so that the overall function of the filter system is little affected. Thus, the damaged primary element can be replaced with the clogged secondary filter element, if a cyclical maintenance of the filter system takes place anyway or the primary filter elements must be replaced.

In principle, the raw gases filtered with the filter system according to the invention may be raw gases of very different temperatures. However, the filter system according to the invention is particularly suitable for the filtration of hot raw gases having temperatures in the range of about 200 ° C to about 1800 ° C.

According to one embodiment of the invention, the primary filter module comprises at least one primary filter element and the secondary filter module comprises at least one secondary filter element, wherein each primary filter element is assigned at least one secondary filter element which is in fluid communication with the primary filter element. By arranging a plurality of filter elements within a filter module, on the one hand, the filter performance of the filter system can be increased. On the other hand, in the event of damage to only one filter element of a filter module, the remaining filter elements of the filter module can initially continue to be operated without difficulty.

The primary filter elements and / or the secondary filter elements of a module may be arranged in rows or clusters. Such an arrangement of filter elements is often referred to as a filter battery. Each primary filter element may be adapted to filter solid particles from the raw gas flowing through, whereas each secondary filter element may be provided with at least one catalyst for catalytically converting pollutants contained in the raw gas and may be configured to filter solid particles from the raw gas ,

Expediently, exactly one secondary filter element is assigned to each primary filter element and the primary filter element and the secondary filter element are each designed as a hollow body with a central interior, in particular substantially as a hollow cylinder, and the interior spaces are in fluid communication with one another. In this case, a primary filter element with the associated secondary filter element forms a kind of independent filter system unit. Preferably, the central interiors of a primary filter element and the associated secondary filter element are arranged coaxially with each other. This allows a particularly good fluid connection of the two filter elements through their interiors.

Advantageously, the primary and secondary filter elements are connected by a carrier plate assembly, wherein the primary and secondary filter elements are arranged on opposite sides of the carrier plate assembly and protrude from the carrier plate assembly in opposite directions, each filter element pair consisting of a primary filter element and the associated secondary filter element, a through hole of the Assigned carrier plate assembly through which the respective primary filter element is in fluid communication with the associated secondary filter element. Because the primary filter elements are not connected directly but via the carrier plate arrangement to the associated secondary filter element, it is possible, for example, to replace a damaged primary filter element individually. In the carrier plate assembly can thus be provided a plurality of through holes, through which the primary filter elements are connected to the associated secondary filter elements. The carrier plate assembly with the primary filter elements and secondary filter elements held thereon thus form a filter module that can be transported and / or mounted as a unit. The connection of a primary filter element and the associated secondary filter element can in this case in particular be such that a common space, which is formed by the two interiors of the primary filter element and the associated secondary filter element and the associated passage opening, has the smoothest possible inner wall

Such a carrier plate assembly may comprise a base plate in which an axial portion of the through hole is formed. Preferably, a primary filter element is then inserted into the passage opening starting from an upper side of the base plate, passes through it and is held on the base plate. This concludes this Primary filter element in particular flush with the top of the base plate. However, it is also possible that the primary filter element protrudes beyond the top of the base plate or that the primary filter element does not quite reach the level of the top of the base plate. When one or the other alternative can be advantageous, is described in more detail below. If the carrier plate assembly has a plurality of through holes for a plurality of filter element pairs, the base plate may include a corresponding axial portion for each through hole of the plurality of through holes.

Preferably, each primary filter element in the form of a filter candle with a substantially hollow cylindrical filter candle body, which is open at its end facing away from the support plate assembly end, in particular hemispherical, closed and formed at its opposite, pointing to the support plate assembly end open. Such filter candles have been proven, are commercially available and therefore relatively inexpensive to purchase.

Advantageously, in the top of the support plate assembly, in particular in the top of the base plate, surrounding the passage opening, in particular annular, recess is formed which defines a support surface, and at the open end of the filter cartridge body, a radially projecting collar is formed on the support surface of the Deepening lies. As a result, the filter cartridge is held on the base plate and fixed axially and / or radially.

Conveniently, the cross section of the axial portion of the through hole in the base plate is larger than the cross sections of the central interiors of a primary filter element and the associated secondary filter element, so that when the primary filter element is inserted into the axial portion of the through hole in the base plate, the transition between the inner walls of both interiors substantially smooth, d. H. without protrusions and / or edges, runs. This is particularly important because it allows unnecessary turbulence of the gas flowing through can be avoided. In addition, fines particles can not deposit on such projections and clog the interiors. In one example, both the cross section of the central interior of a filter candle as a primary filter element and the cross section of the central interior of the secondary filter element are circular. Then, the diameter of the circular cross section of the axial section of the passage opening in the base plate at least partially corresponds to the diameter of the identical cross sections of the two central internal spaces plus twice the wall thickness of the filter element hollow body.

Preferably, the support plate assembly comprises a pressure plate in which an axial portion of the through hole is formed and which is mounted on the top of the base plate. The pressure plate allows a stable and / or secure fit of one or more primary filter elements in the base plate. In the case of a filter cartridge as a primary filter element, the collar protrudes beyond the top of the base plate, mounted on the surface of the base plate pressure plate ensures that the collar of the filter cartridge is pressed firmly against the support surface of the recess. If the collar of the filter cartridge does not quite reach the level of the upper side of the base plate, the pressure plate can prevent at least lateral tilting of the filter cartridge and / or expulsion of the filter cartridge from the base plate by the flow of the raw gas. For example, if the filter cartridge consists of a relatively hard and brittle ceramic and the collar of the filter cartridge does not quite reach the level of the upper side of the base plate, an elastic sealing element can be arranged in the region between the collar and the pressure plate. Such a density element protrudes in an uncompressed state over the top of the base plate and exerts in a mediated by the mounting of the pressure plate compressed state an elastic restoring force and thus allows a particularly tight fit of the filter cartridge. If the carrier plate assembly has a plurality of through holes for a plurality of filter element pairs, the pressure plate may, as before, the base plate include a corresponding plurality of axial sections.

Advantageously, the cross section of the axial section of the passage opening in the pressure plate coincides with the cross sections of the central interior spaces of a primary filter element and the associated secondary filter element.

According to one embodiment of the invention, a secondary filter element carries at a front end a mounting flange which is fixed on the upper side of the carrier plate arrangement, in particular on the upper side of the base plate, in particular by means of screws or a bayonet closure. The mounting flange allows easy attachment of the secondary filter element to the carrier plate assembly. An attachment of the mounting flange directly on top of the base plate has the advantage that can be dispensed with the installation of an additional pressure plate on the top of the base plate. In this case, the mounting flange assumes the function of a pressure plate and ensures a stable and / or secure fit of the corresponding Secondary filter element associated primary filter element in the base plate. However, attachment of the mounting flange on top of a pressure plate mounted on the surface of the base plate may also be advantageous. This is the case, for example, if it is to be prevented that the removal of a secondary filter element has a negative effect on the stable seating of the associated primary filter element.

Preferably, each primary filter element is designed as a surface filter and / or each secondary filter element is designed as a depth filter.

Surface filters retain solid particles on their surface, whereas depth filters hold solid particles in their interior, with the solid particles permanently setting the depth filter. However, it is also conceivable that each secondary filter element filters the solid particles by means of a surface filtration layer from the raw gas and the at least one catalyst of the surface filtration layer is arranged downstream in the flow direction.

Advantageously, the at least one catalyst is a vanadium-containing catalyst. However, the at least one catalyst may also be any other catalyst suitable for use in hot gas filtration. For example, it may also be based on precious metals such as platinum, palladium and / or rhodium. Preferably, the pollutant to be converted is a nitric oxide (NO _x ), such as NO and / or NO ₂ , and the at least one catalyst is capable of converting this nitric oxide (NO _x ) into nitrogen (N ₂ ), in particular by selective catalytic reduction (SCR). Selective means that preferably nitrogen oxides (NO _x ) are reduced while undesirable side reactions such as the oxidation of sulfur dioxide to sulfur trioxide are largely suppressed. The reduction of the nitrogen oxides (NO _x ) to nitrogen (N ₂ ) and water (H ₂ O) can be carried out by means of ammonia NH ₃ and a suitable catalyst, in particular a vanadium-containing catalyst. In this connection, for example, catalysts consisting essentially of titanium dioxide, vanadium pentoxide and / or tungsten dioxod, catalysts based on zeolites and / or catalysts based on activated carbon can be used. Exemplary reactions for the reduction of nitrogen oxides contained in the crude gas are: 4NH ₃ + 4NO + O ₂ → 4N ₂ + 6H ₂ O (1) 2NH ₃ + NO + NO ₂ → 2N ₂ + 3H ₂ O (2) 8NH ₃ + 6NO ₂ → 7N ₂ + 12H ₂ O (3)

Here, the reaction equation (1) is referred to as "standard SCR", the reaction equation (2) as "fast SCR" and the reaction equation (3) as "NO ₂ SCR". Such selective catalytic reductions are advantageous since nitrogen oxides are thereby removed from the flue gas with high efficiency.

Advantageously, each secondary filter element has a particularly highly porous and / or channeled catalyst carrier, in which the at least one catalyst is incorporated. The catalyst support may consist of ceramic moldings and / or vacuum moldings and / or high-temperature wool and / or bulk material. However, any other known catalyst support can be used. The selection of the appropriate material for the catalyst support depends mainly on the chemistry of the catalyst and on how the catalyst is applied to the support material.

Conveniently, the wall thickness and / or the length and / or the material and / or the porosity of each secondary filter element is selected in accordance with the amount of catalyst stored in the catalyst carrier.

Preferably, each secondary filter element has a support basket for enclosing and / or supporting the catalyst support. Such a support basket is particularly useful when using bulk material or loose high-temperature wool as a catalyst carrier to ensure sufficient stability of the secondary filter element. Depending on the material and stability of the material of the catalyst support double or single-walled support baskets can be used. The support basket may advantageously have the form of a double-walled hollow cylinder, wherein between an inner wall and an outer wall of the double-walled hollow cylinder, a cavity is formed, in which the catalyst carrier is located. The cavity may for example have a circular cross-section. Likewise, the support basket may have the shape of a single-walled hollow cylinder. The walls of such support baskets may for example consist of a wire mesh. In general, however, the use of a support basket is not absolutely necessary, especially not if the catalyst support consists of a dimensionally stable part.

The aforementioned object of the invention is also achieved by a method for filtering a hot raw gas, such as a combustion and / or process gas, in particular by means of the filter system according to the invention. Here, in a first step, a raw gas to be purified is passed through a primary filter module to filter solid particles out of this, and is in a second step passed through a secondary filter module to convert catalytically contained therein pollutants, wherein a secondary filter module is used, which is designed to filter solid particles from the raw gas.

Preferably, a primary filter module is used which comprises at least one primary filter element, which is formed as a hollow body with a central interior and surrounding this central interior wall, wherein the raw gas to be purified flows through the wall of the primary filter element in the central interior of the primary filter element, wherein solid particles to the surface of the primary filter element are retained. The primary filter element is thus flowed through from outside to inside, forming so-called filter cake on the outer surface of the primary filter element. Such filter cake can be removed by means of compressed air cleaning ("jet-pulse cleaning") by means of a purge gas flow from the clean gas side ago. Therefore, with regular cleaning, the primary filter element can be used repeatedly and does not need to be replaced frequently unless it is damaged.

Advantageously, a secondary filter module is used which comprises at least one secondary filter element which is designed as a hollow body with a central interior and a wall surrounding this central interior, wherein the gas leaving the primary filter module, in the central interior of the secondary filter element and from there through the Wall of the secondary filter element flows, solid particles penetrate deep into the wall and are held there. By means of this depth filter function of the catalytic secondary filter element, damage to the secondary filter element as well as the subsequent systems is prevented in the event of damage to the primary filter element.

Furthermore, the aforementioned object of the invention is also achieved according to the invention by a filter element according to one of claims 26 to 36.

With the filter system described above, therefore, a filter system is provided for the first time, which has an increased availability and reliability with simultaneously reduced operating costs.

Further features and advantages of the present invention will become apparent from the following description of two embodiments of the filter system according to the invention with reference to the accompanying drawings. In it is:

1 a filter system according to the invention according to a first embodiment of the present invention; and

2 a filtration device with a filter system according to the invention according to a second embodiment of the present invention.

The 1 shows a filter system according to the invention 1 for filtering a hot raw gas according to a first embodiment of the present invention. The filter system 1 includes a primary filter module 2 , which is designed to filter solid particles from a flowing raw gas, and a separate secondary filter module 3 that is the primary filter module 2 is arranged downstream and with the primary filter module 2 is in fluid communication to from which the primary filter module 2 flowing through prefiltered gas. The secondary filter module 3 is provided with at least one catalyst for the catalytic conversion of chemical compounds contained in the flowing raw gas, in particular pollutants and is a safety filter module which is designed to filter solid particles from the raw gas. In this first embodiment, the primary filter module comprises 2 exactly one primary filter element 4 and includes the secondary filter module 3 a secondary filter element 5 that is the primary filter element 4 assigned. The primary filter element 4 and the secondary filter element 5 each have the shape of a hollow body 6 . 7 with a central interior 8th . 9 on. More specifically, the primary filter element 4 the shape of a filter candle with a substantially hollow cylindrical filter candle body 6 on, at one end 10 Hemispherical closed and at its opposite end 11 is open, wherein at the open end 11 a radially projecting collar 12 is formed. The primary filter element 4 is formed in this embodiment as a surface filter. Also the secondary filter element 5 is essentially designed as a hollow cylinder. It includes a support basket 13 in the form of a double-walled hollow cylinder, wherein between an inner wall 14 and an outer wall 15 the double-walled hollow cylinder a cavity 16 is formed, in which a catalyst carrier 17 in the form of high temperature wool. The inner and outer walls 14 . 15 of the support basket 13 consist in the present embodiment of a wire mesh and enclose the catalyst support 17 and support him. In the catalyst carrier 17 in which a vanadium-containing catalyst is incorporated, in other embodiments, it may also be a ceramic molding, a vacuum molding or bulk material. However, any other catalyst may be used as long as it is capable of converting nitrogen oxides to nitrogen. The secondary filter element 5 carries on a frontal end 18 his body 7 one mounting flange 19 , The secondary filter element 5 is formed in this embodiment as a depth filter. The interiors 8th . 9 of the primary filter element 4 and the associated secondary filter element 5 are in fluid communication with each other and are arranged coaxially with each other.

The primary filter element 4 is about a support plate assembly 20 with the secondary filter element 5 connected, wherein the primary filter element 4 on one side of the carrier plate assembly 20 and the secondary filter element 5 on the opposite side of the carrier plate assembly 20 is arranged. The primary and secondary filter elements 4 . 5 Stand from the carrier plate assembly 20 in opposite directions. The filter element pair consisting of the primary filter element 4 and the secondary filter element 5 , is a passage opening 21 the carrier plate assembly 20 assigned, through which the filter element pair is in fluid communication. The carrier plate arrangement 20 includes a base plate 22 in which an axial section 21a the passage opening 21 is trained. In the top 23 the base plate 22 is one the axial section 21a the passage opening 21 surrounding depression 24 formed, which has a bearing surface 25 Are defined. The primary filter element 4 is starting from the top 23 in the axial section 21a the passage opening 21 inserted, passes through the base plate 22 and is at the base plate 22 held by the collar 12 the filter candle body 6 on the support surface 25 the depression 24 lies. Furthermore, the carrier plate arrangement comprises 20 a printing plate 26 in which an axial section 21b the passage opening 21 is formed and the on the top 23 the base plate 22 is mounted. Because the thickness of the collar 12 the height of the depression 24 corresponds, closes the primary filter element 4 with the top 23 the base plate 22 flush off.

The secondary filter element 5 is by means of its mounting flange 19 on the top 27 the carrier plate assembly 20 ie on the top 28 the printing plate 26 , detachably fastened. This attachment can be done in particular by means of screws or a bayonet lock, which in the 1 but not shown. The diameters of the circular cross sections of the two central interiors 8th . 9 and the axial section 21b the passage opening 21 in the printing plate 26 agree. Greater than this cross-sectional diameter is only the diameter of the circular cross section of the axial section 21a the passage opening 21 in the base plate 22 , This will allow a common space through the interior 8th in the axial section 21a the passage opening 21 in the base plate 22 used primary filter element 4 , the interior 9 of the secondary filter element 5 as well as the passage opening 21 is formed, having as smooth as possible inner wall without projections and gradations.

The 2 shows a filtration device 29 holding a filter container 30 with an interior 31 as well as one in the interior 31 arranged inventive filter system 1 according to a second embodiment of the present invention. The filter system 1 includes a primary filter module 2 , the six primary filter elements 4 in the form of filter cartridges, and a secondary filter module 3 , the six secondary filter elements 5 wherein each primary filter element 4 exactly one secondary filter element 5 assigned. Both the primary 4 as well as the secondary filter elements 5 are therefore arranged in a kind of cluster. The primary and secondary filter elements 4 . 5 are by a carrier plate assembly 20 connected to the interior 31 of the filter container 30 in a raw gas room 32 and a clean gas room 33 divided. Two ports A and B of the filter tank 30 are located in the area of the raw gas space 32 while a third port C of the filter tank 30 in the area of the clean gas room 33 located. Each filter element pair consisting of a primary filter element 4 and the associated secondary filter element 5 , is one of a total of six through holes 21 the carrier plate assembly 20 assigned by the respective primary filter element 4 with the associated secondary filter element 5 is in fluid communication. The raw gas space 32 is thus about the filter system 1 with the clean gas room 33 in fluid communication.

Both the structure of the carrier plate assembly 20 as well as the structure of the primary and secondary filter elements 4 . 5 is already related to 1 described structure. In contrast to 1 However, they have the different secondary filter elements 5 in the 2 different catalyst supports 17 on. For example, the secondary filter element points 5 at the position I, a ceramic molding as a catalyst support 17 due to its dimensional stability without support basket 13 gets along. In contrast, the two secondary filter elements 5 at positions II and III one support basket each 13 on that in 2 is indicated by a dashed line. Because the secondary filter element 5 at position II has bulk material as catalyst carrier 17 on and the secondary filter element 5 at position III has high temperature wool as a catalyst carrier 17 on, both catalyst supports 17 without support basket 13 would not have sufficient stability. In other embodiments, each of the six secondary filter elements 5 of course, any other catalyst support 17 with or without support basket 13 exhibit.

During operation of the filtration device 29 a hot raw gas passes through port A of the filter container 30 in the raw gas room 32 of the filter container 30 and flows from there through the filter candle body 6 in the central interiors 8th the filter candles 4 , This dust particles store on the outside of the filter cartridge body 6 from and form so-called filter cake. The raw gas cleaned of dust particles then flows into the central interior spaces 9 the secondary filter elements 5 and from there through the body 7 the secondary filter elements 5 , wherein pollutants contained in the raw gas by a catalyst in the secondary filter elements 5 be converted catalytically. The largely freed of dust particles and pollutants gas then flows into the clean gas room 33 and leaves the filter container from there 30 through port C of the filter tank 30 , Since it is the secondary filter elements 5 can be catalytic de-dusting filters, even in case of damage to one or more of the filter cartridges 4 a dust-free gas in the clean gas room 33 be guaranteed. In contrast to the filter candles 4 , which are surface filters, are the secondary filter elements 5 by depth filters that hold the dust particles in their interior. In normal operation of the filtration device 29 However, the filtering out of solid particles takes place on the filter cartridges 4 , The resulting filter cake on the outer sides of the filter cartridge body 6 be by compressed air cleaning, ie backwashing the filter cartridges 4 by means of a purge gas stream from the clean gas side ago, away. By the purge gas flow, the dust particles from the outer surfaces of the filter cartridge body 6 in the direction of port B of the filter tank 30 blown and leave from there the filter container 30 ,

LIST OF REFERENCE NUMBERS

1

filter system

2

Primary filter module

3

Secondary filter module

4

Primary filter element

5

Secondary filter element

6

Filter plug body

7

Body of the secondary filter element

8th

central interior of the primary filter element

9

central interior of the secondary filter element

10

closed end

11

open end

12

collar

13

support cage

14

inner wall

15

outer wall

16

cavity

17

catalyst support

18

frontal end

19

mounting flange

20

Platen assembly

21

Through opening

21a

axial portion of the through hole in the base plate

21b

axial portion of the through hole in the pressure plate

22

baseplate

23

Top of the base plate

24

deepening

25

bearing surface

26

printing plate

27

Top of the carrier plate assembly

28

Top of the printing plate

29

filtration device

30

filter container

31

Interior of the filter tank

32

raw gas

33

Clean gas chamber

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2006/103040 A1 [0003, 0004]

Claims (33)

Filter system ( 1 ) for the filtration of a hot raw gas, such as a combustion and / or process gas, comprising: a primary filter module ( 2 ), which is designed to filter solid particles from a flowing raw gas; and a separate secondary filter module ( 3 ), the primary filter module ( 2 ) is arranged downstream and with the primary filter module ( 2 ) is in fluid communication from which the primary filter module ( 2 flowing through prefiltered gas leaving the secondary filter module ( 3 ) is provided with at least one catalyst for the catalytic conversion of chemical compounds contained in the flowing raw gas, in particular pollutants, characterized in that the secondary filter module ( 3 ) is a safety filter module, which is designed to filter solid particles from the raw gas. Filter system ( 1 ) according to claim 1, characterized in that the primary filter module ( 2 ) at least one primary filter element ( 4 ) and the secondary filter module ( 3 ) at least one secondary filter element ( 5 ), wherein each primary filter element ( 4 ) at least one secondary filter element ( 5 ) associated with the primary filter element ( 4 ) is in fluid communication. Filter system ( 1 ) according to claim 2, characterized in that each primary filter element ( 4 ) exactly one secondary filter element ( 5 ) and that the primary filter element ( 4 ) and the secondary filter element ( 5 ) each as a hollow body ( 6 . 7 ) with a central interior ( 8th . 9 ), in particular substantially as a hollow cylinder, are formed and the interiors are in fluid communication with each other. Filter system ( 1 ) according to claim 3, characterized in that the central interiors ( 8th . 9 ) of a primary filter element ( 4 ) and the associated secondary filter element ( 5 ) are arranged coaxially with each other. Filter system ( 1 ) according to claim 3 or 4, characterized in that the primary and secondary filter elements ( 4 . 5 ) by a carrier plate arrangement ( 20 ), the primary and secondary filter elements ( 4 . 5 ) on opposite sides of the carrier plate assembly ( 20 ) are arranged and from the carrier plate assembly ( 20 ) protrude in opposite directions, each filter element pair consisting of a primary filter element ( 4 ) and the associated secondary filter element ( 5 ), a passage opening ( 21 ) of the carrier plate arrangement ( 20 ), by which the respective primary filter element ( 4 ) with the associated secondary filter element ( 5 ) is in fluid communication. Filter system ( 1 ) according to claim 5, characterized in that the carrier plate arrangement ( 20 ) a base plate ( 22 ), in which an axial section ( 21a ) of the passage opening ( 21 ), and in that a primary filter element ( 4 ) in the passage opening ( 21 ) starting from a top side ( 23 ) of the base plate ( 22 ) is inserted, this passes through and on the base plate ( 22 ) is held. Filter system ( 1 ) according to claim 6, characterized in that each primary filter element ( 4 ) the shape of a filter candle with a substantially hollow cylindrical filter cartridge body ( 6 ), which at its from the carrier plate assembly ( 20 ) groundbreaking end ( 10 ), in particular hemispherical, closed and at its opposite, to the support plate assembly ( 20 ) pointing end ( 11 ) is open. Filter system ( 1 ) according to claim 7, characterized in that in the top ( 27 ) of the carrier plate arrangement ( 20 ), especially in the top ( 23 ) of the base plate ( 22 ), one the passage opening ( 21 ) surrounding, in particular annular, recess ( 24 ) is formed, which has a bearing surface ( 25 ) and that at the open end ( 11 ) of the filter cartridge body ( 6 ) a radially projecting collar ( 12 ) is formed on the support surface ( 25 ) of the depression ( 24 ) lies. Filter system ( 1 ) according to one of claims 6 to 8, characterized in that the cross section of the axial section ( 21a ) of the passage opening ( 21 ) in the base plate ( 22 ) larger than the cross sections of the central interiors ( 8th . 9 ) of a primary filter element ( 4 ) and the associated secondary filter element ( 5 ), such that when the primary filter element ( 4 ) in the axial section ( 21a ) of the passage opening ( 21 ) in the base plate ( 22 ), the transition between the inner walls of the two interiors ( 8th . 9 ) is substantially smooth. Filter system ( 1 ) according to one of claims 6 to 9, characterized in that the carrier plate arrangement ( 20 ) a printing plate ( 26 ), in which an axial section ( 21b ) of the passage opening ( 21 ) is formed and on the top ( 23 ) of the base plate ( 22 ) is mounted. Filter system ( 1 ) according to claim 10, characterized in that the cross section of the axial section ( 21b ) of the passage opening ( 21 ) in the pressure plate ( 26 ) with the cross sections of the central interior spaces ( 8th . 9 ) of a primary filter element ( 4 ) and the associated secondary filter element ( 5 ) matches. Filter system ( 1 ) according to one of claims 5 to 11, characterized in that a secondary filter element ( 5 ) at a front end ( 18 ) a mounting flange ( 19 ), which is on the top ( 27 ) of the carrier plate arrangement ( 20 ), especially on the top side ( 23 ) of the base plate ( 22 ), in particular by means of screws or a bayonet lock, is attached. Filter system ( 1 ) according to one of claims 2 to 12, characterized in that the primary filter elements ( 4 ) and / or the secondary filter elements ( 5 ) are arranged in rows or clusters. Filter system ( 1 ) according to one of claims 2 to 13, characterized in that each primary filter element ( 4 ) is designed as a surface filter and / or each secondary filter element ( 5 ) is designed as a depth filter. Filter system ( 1 ) according to one of the preceding claims, characterized in that the at least one catalyst is a vanadium-containing catalyst. Filter system ( 1 ) according to any one of the preceding claims, characterized in that the pollutant to be converted is a nitric oxide and the at least one catalyst is suitable to convert this nitric oxide in particular by means of selective catalytic reduction in nitrogen. Filter system ( 1 ) according to one of claims 2 to 16, characterized in that each secondary filter element ( 5 ) a particularly highly porous and / or channel-traversed catalyst support ( 17 ), in which the at least one catalyst is incorporated. Filter system ( 1 ) according to claim 17, characterized in that the catalyst support ( 17 ) consists of ceramic moldings and / or vacuum moldings and / or high temperature wool and / or bulk material. Filter system ( 1 ) according to claim 17 or 18, characterized in that the wall thickness and / or the length and / or the material and / or the porosity of each secondary filter element ( 5 ) in accordance with the amount of in the catalyst support ( 17 ) embedded catalyst is selected. Filter system ( 1 ) according to one of claims 17 to 19, characterized in that each secondary filter element ( 5 ) a support basket ( 13 ) for enclosing and / or supporting the catalyst support ( 17 ) having. Filter system ( 1 ) according to claim 20, characterized in that the support basket ( 13 ) has the form of a double-walled hollow cylinder, wherein between an inner wall ( 14 ) and an outer wall ( 15 ) of the double-walled hollow cylinder a cavity ( 16 ) is formed, in which the catalyst support ( 17 ) is located. Filter system ( 1 ) according to claim 20, characterized in that the support basket ( 13 ) has the shape of a single-walled hollow cylinder. Filter element ( 5 ) for use as a secondary filter element in a filter system ( 1 ) for the filtration of a hot raw gas according to any one of claims 2 to 22, as an elongated hollow body ( 7 ) with a central interior surrounded by a wall ( 9 ), wherein the hollow body ( 7 ) closed at one end face and at the opposite end face ( 18 ) is open so that the raw gas at the open end ( 18 ) in the interior ( 9 ), wherein the hollow body ( 7 ) is provided with at least one catalyst for the catalytic conversion of pollutants contained in the raw gas and with a particulate filter for filtering out solid particles from the raw gas, characterized in that the particulate filter is a depth filter. Filter element ( 5 ) according to claim 23, characterized in that the hollow body ( 7 ) is a hollow cylinder. Filter element ( 5 ) according to claim 23 or 24, characterized in that the hollow body ( 7 ) at its open end ( 18 ) a mounting flange ( 19 ) for attachment to the top ( 27 ) a carrier plate arrangement ( 20 ) of the filter system ( 1 ) wearing. Filter element ( 5 ) according to any one of claims 23 to 25, characterized in that the wall of the hollow body ( 7 ) a highly porous and / or channeled catalyst support ( 17 ), in which the at least one catalyst is incorporated. Filter element ( 5 ) according to claim 26, characterized in that the catalyst support ( 17 ) consists of ceramic moldings and / or vacuum moldings and / or high temperature wool and / or bulk material. Filter element ( 5 ) according to claim 26 or 27, characterized in that the wall thickness and / or the length and / or the material and / or the porosity of the hollow body ( 7 ) in accordance with the amount of in the catalyst support ( 17 ) embedded catalyst is selected. Filter element ( 5 ) according to one of claims 26 to 28, characterized in that the Wall of the hollow body ( 7 ) continue a support basket ( 13 ) for enclosing and / or supporting the catalyst support ( 17 ) having. Filter element ( 5 ) according to claim 29, characterized in that the support basket ( 13 ) has the form of a double-walled hollow cylinder, wherein between an inner wall ( 14 ) and an outer wall ( 15 ) of the double-walled hollow cylinder a cavity ( 16 ) is formed, in which the catalyst support ( 17 ) is located. Filter element ( 5 ) according to claim 29, characterized in that the support basket ( 13 ) has the shape of a single-walled hollow cylinder. Filter element ( 5 ) according to one of claims 23 to 31, characterized in that the at least one catalyst is a vanadium-containing catalyst. Filter element ( 5 ) according to one of claims 23 to 32, characterized in that the pollutant to be converted is a nitric oxide and the at least one catalyst is suitable for converting this nitric oxide into nitrogen in particular by means of selective catalytic reduction.

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