EP0805915A1

EP0805915A1 - Device for removing substances in gas and vapour form in a stream of exhaust air

Info

Publication number: EP0805915A1
Application number: EP96900497A
Authority: EP
Inventors: Axel Hartenstein
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-01-24
Filing date: 1996-01-24
Publication date: 1997-11-12
Anticipated expiration: 2016-01-24
Also published as: EP0805915B1; AU4429496A; ATE191061T1; DE59604776D1; WO1996023134A1

Abstract

In a device for removing substances in gas and vapour form in a stream of exhaust air (18) with an active material on the surface of a carrier, the exhaust air flows through the substrate arranged in a housing (68) with gas inlet (90) and outlet stubs (78). In the housing (68) there are several axially separated cartridges (12) closed on one side, with an indeformable, perforated inner casing and an outer casing permeable to gases with little resistance as a carrier with the active material for the catalysis, adsorption or transformation of organic dusts and aerosols into gas placed on its surface. The cartridges (12) are assembled into at least one removable insert (70) or removable modules, each with individually releasable cartridges (12). The device makes it possible to purify gaseous and vapour flows of exhaust air at varying and low charges and low temperatures, where the devices may be spatially andlocally separated.

Description

Device for exhaust air purification of gaseous and vaporous substances in an exhaust air stream

The invention relates to a device for exhaust air purification of gaseous and vaporous substances in an exhaust air stream, with an active material on the surface of a carrier, the exhaust air flowing through the carrier arranged in a housing with gas supply and gas discharge nozzles.

Exhaust air purification systems are often operated as thermal exhaust air purification units depending on the harmful gas in the exhaust air at high temperatures. The harmful gases occur in fluctuating concentrations and often not at the temperatures at which they can be burned in a flame or by means of a catalyst. Therefore, they have to be burned or heated up with a lot of fuel, the heat often not being able to be used or either not being used or being used at a lesser extent at the time of the combustion. Expensive installations for storage or use of heat are often required or even required by law. In addition, the location of the pollution is sometimes far from the incineration plant, so that long and expensive channels have to be laid.

In view of these circumstances, the inventor has set himself the task of creating a device of the type mentioned at the outset which enables exhaust air purification and thus pollutant removal at temperatures as low as possible and which allows a simple recycling concept with a durable, robust construction and is universally usable.

In order to achieve the object according to the invention, one-sidedly spaced, axially spaced closed cartridges are arranged with a dimensionally stable, perforated inner jacket and an outer jacket designed to be gas-permeable with low resistance as a carrier with the active material for catalysis, adsorption or conversion of organic dusts and aerosols into gas.

Special and further developed embodiments of the device according to the invention are the subject of dependent patent claims.

With the device according to the invention, there is the advantage of a large, predetermined and defined gas path over the entire inflow area of the cartridges. In particular, gaseous and vaporous exhaust air streams can be cleaned with fluctuating and weak loads and at low temperatures, the devices being able to be spatially and locally separated.

The cartridges with the carriers for catalysis, adsorption and conversion of organic dusts and aerosols into gas can be arranged in spatially and spatially separate housings or units, and the adsorber unit can even be mobile. The outer jacket can be constructed of active material or coated with it.

In a particularly preferred embodiment of the device according to the invention, the cartridges are combined to form at least one removable insert or removable modules, each with individually detachably attached cartridges.

During the operation of the device according to the invention, hereinafter referred to as exhaust air cleaning system, incombustible deposits can deposit to a very small extent on the active material of the cartridges. Certain substances can also poison or clog the active material. Are the properties of the active material consequently non-combustible? Deposits or no longer sufficient due to poisoning, the insert or module in question is removed, one or more cartridges removed and the active material cleaned or renewed. Even when the active material is renewed, the inner jacket of cartridges, also called perforated tube, can be used several times. This saves valuable resources and increases profitability.

The cartridges are preferably closed downstream and in this case must be open upstream. They are screwed on the gas inlet side with a cartridge holder open in the area of the cartridges, on the gas outlet side with a cartridge holder open in the area between the cartridges. Particular attention must be paid to the seal, there must be no creeping gas flows past the filter medium, rather the entire exhaust gas flow must be conducted through the filter medium.

The screw connection of the individual parts creates solid catalyst inserts or catalyst modules that are stable in themselves. The seal can be made by a preferably multi-part clamping piece, which is arranged on the inside adjacent to the downstream cartridge holder and acts on the rigid inner jacket of the cartridges via a seal.

The holding and supporting parts of the catalyst system are preferably made of a high-alloy steel. This largely prevents scaling of the metal parts and a very long service life can be achieved. Special attention is paid to the design of the inner shell of cartridges. The porosity is generally achieved by forming round and / or elongated holes in a sheet metal jacket. A cylindrical surface with the necessary mechanical strength can also be achieved with a wire or ribbon grid. The rigid inner jacket has to support the outer jacket of the cartridges with the active material. The outer jacket preferably consists of a heat-resistant, inorganic fiber material made of high-temperature filaments or yarns with high adsorption capacity, wherein the yarns can be designed in a known manner as multifilament yarn or fiber yarn, twisted or untwisted. The filaments or yarns, referred to collectively as fibers, are preferably applied as an at least single-layer structured form. However, the outer jacket can also be applied as a single or multi-layer knitted fabric, knitted fabric, fleece, braid or the like.

The great adsorption capacity of the high-temperature fibers, physically expressed by the high van der Waals forces, is guaranteed by the formation of a high specific surface. The high-temperature fibers used are preferably made of glass or ceramic.

For a very good efficiency of the exhaust air purification system, it is also important that no leaks can occur between the individual inserts or modules, which would result in uncleaned creeping gas flows. Models in particular are preferably sealed against one another with an elastic glass fabric seal.

An exhaust air purification system according to the invention is, thanks to the exchangeable inserts or modules with individually replaceable cartridges, of a simple basic concept, flexible in use and economical to manufacture and operate. The most diverse exhaust air purification systems can be built with a small number of elements. In addition to the inexpensive large series, there is a low level of storage, which further improves the economy.

The carried out with the device according to the invention Catalytic afterburning of carbon monoxide and hydrocarbons in an exhaust air stream is flameless at much lower temperatures than, for example, with thermal afterburning. As a result, less energy is consumed and a relatively small size is also achieved.

Carbon monoxide and hydrocarbons in the exhaust air stream can be concentrated before or simultaneously with the catalytic afterburning by adsorption. For this purpose, an adsorption storage device is connected upstream of the catalyst system in the exhaust air stream. This can consist of fibers, in particular of knitted, woven or braided fibers made of activated carbon, ceramic or glass. Here, the fibers can be coated with the catalytically active material, i.e. the adsorption storage can also serve as a catalyst.

A single-material coating or a mixture of noble metals or of noble metal oxides, in particular of platinum, rhodium, palladium, vanadium, cobalt or their oxides with other metals or. whose oxides are used.

In a preferred embodiment, in particular if the adsorption storage is simultaneously used as a catalyst, the catalyst carrier consists of fibers, in particular of knitted, woven or braided fibers of activated carbon, ceramic or glass. The size can be considerably reduced by using a coated adsorption fiber. By using a catalyst carrier made of fibers, space velocities up to 330000''000000 hh ^{"1 are} too low, compared to 35'000 h ^-1 for one

Ceramic honeycomb body

Organic dusts and aerosols can also be heated in cartridges with active material in a structured form decomposed and brought into the gas phase, which allows their treatment in the exhaust air cleaning system.

In the event that the exhaust air flow has a temperature which is too low for the catalytic afterburning, it can be heated up before it enters the catalytic converter. Another possibility is seen in that the catalyst and / or the cartridges are heated themselves.

The ionization or excitation can also take place by means of electrical fields or chemical additives such as gases. This eliminates the need to heat up and the energy required is many times less than in the case of thermal heating.

The system according to the invention jumps at very low temperatures in the range between a room temperature of about 15 * C to 450 "can and consumes only about 20% of the energy that requires thermal afterburning.

With a relatively high loading of an exhaust stream with carbon monoxide or hydrocarbons, it is passed directly over the catalyst units. An upstream adsorption memory can be provided for the compensation of loading peaks.

If the exhaust air flow is slightly loaded, an adsorber is connected upstream of the catalyst as a store. This adsorption storage adsorbs even the smallest pollutant concentrations. In a second step, desorption is then carried out over a substantially smaller cross section and the desorption stream is subsequently burned in the catalyst. This process can take place independently of fluctuating concentrations of pollutants and at different intervals. The system requires approximately 5% of the energy of a thermal post-combustion and can be installed in the immediate vicinity of the harmful gas source, which increases the installation costs. significantly reduces. It is not necessary to use heat. The partial flow catalysis system has the advantage that it is effective even at low pollutant concentrations in the range from a few ppm to 1000 ppm and more. The pollutants are stored in the adsorption storage and then converted in the catalytic converter as in full-flow catalysis.

The device according to the invention can be used with all hydrocarbons and carbon monoxide and optionally other gaseous compounds, in particular for flameless solvent combustion, catalytic residue combustion and odor removal.

The particular advantage of the invention is that the system starts up at very low temperatures and, above all, can be built up in modules that can be spatially separated. It is even possible that e.g. the adsorption is not the same as gas flow is like cleaning. In this way, inexpensive adsorber modules can be produced, which are installed at issuers and cleaned at a service point.

Areas of application are e.g. Production processes in chemistry, pharmacy and food industry, roasting plants, smokers, paint production and color processing, spraying, painting, textile processing and finishing, ceramic production and processing, fuel exhaust air, wood processing, chipboard exhaust air, printing industry, plastics industry etc.

Further advantages, features and details of the invention result from the following description of preferred exemplary embodiments and from the drawing; this shows schematically in

1 shows a partially cut-away side view of a catalyst module of a stationary ca tester system;

2 shows an end view of the module from the exhaust air inlet side;

3 shows an end view of the module from the exhaust air outlet side;

- Figure 4 is a partially cutaway view of a

Cartridge;

5 shows a partially detailed view of the inner shell of the cartridge; 6 shows a view of a multi-part clamping piece;

7 shows a cut-away view of a mobile catalytic converter system with a catalytic converter insert;

8 shows a radial section at VIII-VIII in FIG. 7;

9 shows a catalyst insert for FIG. 7; -Fig.10 the downstream cartridge holder ofFig.9;

- Fig. 11 the upstream cartridge holder from Fig. 9;

12 shows a small piece of the catalyst insert

Fig.9;

- Fig. 13 shows an axial section through a filter cartridge in the area of the inlet side;

14 shows the principle of a full-flow exhaust air purification system;

- Fig. "» 5 the principle of a partial flow exhaust air cleaning system.

A catalytic converter module 10 of a stationary catalytic converter system according to FIGS. 1 to 3 is essentially of a guader-shaped design, it has a cross section of 150 x 150 mm and a length of 1000 mm. One module comprises nine cartridges 12 with a dimensionally stable inner jacket 14 with a diameter of approximately 34 mm and an outer jacket 16 made of a braided inorganic fiber material which is pulled over the inner jacket 14 in a stocking-like manner.

The cartridges 12 are provided with a closure cap 20 downstream of an exhaust air stream 18. The exhaust gas stream 18 enters the interior 28 of the cartridges 12 that are open upstream enters the interior 26 between the cartridges 12 via the porous inner jacket 14 and the fibrous outer jacket 16. The cleaned exhaust air 18 flows out through openings in the cartridge holder 24. At the inlet end of the upstream open cartridges 12, a coaxial flange sleeve 30 is fastened via a clamping bracket 34. The sleeve 30 passes through correspondingly dimensioned openings 36 in the upstream filter cartridge holder 38. Sealing is carried out by a respective end clamp 34, which is placed on the outer jacket 16 and tightened in the area of the closure cap 20 and the flange sleeve 30.

On the inside, a multi-part clamping piece 40, 42, which is shown in detail in FIG. 6, is screwed to the cartridge holder 38, the screw connection being denoted by 56. This clamping piece serves to seal the interior space 26 around the cartridges 12 on the inlet side and thus to prevent leakage currents. The seals are labeled 44, 46.

Downstream, the cap 20 of the cartridges 12 is attached to the cartridge holder 24 via a threaded bolt 48 and a corresponding nut 50. Finally, the dimensional stability of the catalyst module 10 is further improved in that the cartridge holder 24 has an edge 52 folded inwards and the cartridge holder 38 has a folded edge 54. When modules 10 are stacked, the folded edges 52, 54 form the contact surfaces.

On the outflow side of the catalyst module 10 shown in FIG. 2, the shell-shaped cartridge holder 24 is provided with essentially square cutouts. The cartridges, which are screwed on the end caps 20, leave the interior 26 free, which, thanks to the openings 22, is easily flowed through by the cleaned exhaust air. In the upstream cartridge holder 38 according to FIG. 3, in addition to the openings 36 for the inner jacket of the cartridges, the screw connections 56 for the clamping piece 40, 42 are visible.

The inner jacket 14 of a cartridge 12 (FIG. 1), shown shortened in FIG. 4, comprises at the downstream end the closure cap 20 with a welding bolt 48, which is designed as a threaded rod. At the upstream end of the inner jacket 14, a flange sleeve 30, also called a collar, is drawn on and spot-welded to the inner jacket.

FIG. 5 shows the inner jacket 14 according to FIG. 4, which is also shown shortened. The porosity consists of regularly arranged round holes 58 which are distributed over the entire inner jacket 14. In the present case, the round holes 58 have a diameter of 5 mm and a spacing d of 7 mm on all sides. The hexagonal perforation thus ensures sufficient mechanical stability to support the fibrous outer jacket 16 (FIG. 1).

According to FIG. 6, the multi-part clamping piece, of which an end piece and a middle piece 40, 42 are shown, has essentially semicircular recesses 60, which correspond to the total number of cartridges to be accommodated. The recesses 60 have an approximately 1 mm larger radius than the flange sleeve 30. Furthermore, screw holes 62 are provided, which are used for attachment to the upstream cartridge holder 38 (FIG. 1,3).

7,8 show a mobile catalytic converter system 66 with a removable catalytic converter insert 70 arranged in a catalytic converter housing 68. The housing is embedded in an insulation layer 76 surrounding it. A stationary catalytic converter system in the sense of FIGS. 7, 8 can have any number of catalytic converter modules instead of a catalytic converter insert 70. len Fig.1 included.

The exhaust air stream 18 to be cleaned flows via a flanged-on gas supply nozzle 90 into the catalyst housing 68 in the region of the catalyst insert 70, which is shown in detail in FIG. A gas discharge nozzle 78 is flanged to the catalyst housing 68 downstream.

A pipe 92 with a cable sheath passes through the insulation layer 76 and the catalytic converter housing 68 adjacent to the gas discharge nozzle 78. It is used to insert a measuring probe and is closed when not in use.

A radial section VII-VII according to FIG. 7 is shown in FIG. The catalyst insert 70 comprises nineteen cartridges 12 with an inner jacket 14 and an outer jacket 16. The catalyst housing 68 with the insulation layer 76 is surrounded by a clamping ring 94, which can be locked with a screw connection 96.

FIG. 8 also shows, by way of example, that rod-shaped electrode elements for exciting the vapors and gas by means of electrical fields can be arranged inside the inner jacket 14.

The catalyst insert 70 shown in FIG. 9 essentially corresponds to a catalyst module 10 according to FIG. 1. In the case of hexagonal design of the cartridge holders 24, 38 forming the outer circumference or of their folded edges 52, 54 (FIG. 1), the catalyst insert 70 becomes the catalyst module 10 with nineteen cartridges 12. The front cartridge 12 of the middle level is visible in full size, the the rest are partially hidden.

In the case of a larger exhaust air volume flow, the catalyst insert 70 can be enlarged by adding further rings of cartridges. For mechanical and static reasons a limit for the number of cartridges must be set for a catalyst insert, the catalyst insert is replaced by several catalyst modules.

The cartridge holder 24 according to FIG. 10 on the outlet side essentially corresponds to FIG. 2. However, because of the hexagonal structure of the catalyst insert 70, the openings 22 are triangular. The nineteen holes 98 serve to receive threaded bolts 48 (FIG. 4) for fastening the cartridges, not shown. Analogously, the cartridge holder 38 according to FIG. 11 corresponds to FIG. 3 above. The numerous holes 100 serve to fasten a multi-part clamping piece.

A clamping piece according to FIG. 12 assigned to the cartridge holder 38 on the inlet side is formed in five parts. The two terminal clamps 40 have on their straight longitudinal side three substantially semicircular recesses 60 which have a radius which is approximately 1 mm larger than the flange sleeves 30 (FIG. 4). The four middle clamping pieces 41 have three to five corresponding semicircular recesses 60 on their long sides. Between the clamping pieces 40, 41 there is a slot 104 about 1 mm wide. The arrangement of the holes 100 for the screw connections 56 (FIG. 1.9) corresponds exactly to that of the cartridge holder 38 arranged upstream.

Fig. 13 shows a variant of the sealing of the interior 26 (Fig. 1, 2) outside the cartridges in a catalytic converter module or catalytic converter insert. The inner jacket 14 has a spot-welded flange sleeve 30 adjacent to the end face. A clamping piece 40, 42 lying on the end face of this flange sleeve presses the flange sleeve 30 against the seal 44 and the cartridge holder 38 when the screws 56 (FIG. 1.9) are tightened. The cartridges 12 therefore do not have to be held in the cartridge holder 38 with a seal. 14, the exhaust air loaded with hydrocarbons enters a treatment room 116 via an exhaust air inlet opening 112 and a vetilator 114. A catalyst 118 is arranged in this treatment space 116. Before entering the catalytic converter 118, the exhaust air can be preheated via a hot air blower 120 connected to the treatment room 16. After exiting the catalytic converter 118, the cleaned exhaust air leaves the treatment room 116 via a clean air outlet opening 122.

A partial flow exhaust air purification system 130 shown in FIG. 15 has an exhaust air inlet opening 132 and a fan 134 connected to it. A catalyst 138 is arranged in a treatment room 136. A hot air blower 140 is connected upstream of the catalytic converter 138 to the treatment room 136 for preheating the exhaust air. The exhaust air here opens into an adsorption store 144 in which carbon monoxide or hydrocarbons are adsorbed. The exhaust air cleaned in this way leaves the adsorption storage 144 via the clean air outlet opening 142. If the adsorption storage 144 is loaded sufficiently, the hydrocarbons are desorbed by introducing a desorption gas via a desorption line 146 by means of a compressor 148, possibly heated via the hot air blower 140 and then the catalyst 138 fed. After passing through the catalyst 138, the cleaned exhaust air is led via a connecting line 150 to the clean air outlet opening 142.

The process according to the invention acts selectively particularly well for CO from approx. 150 ^β C and, depending on the temperature range and catalyst material, good for CH.

Claims

claims

1. Device for exhaust air purification of gaseous and vaporous substances in an exhaust air flow (18), with an active material on the surface of a support, the exhaust air flowing through the support arranged in a housing (68) with gas supply (90) and gas discharge connections (78) ,

characterized in that

in the housing (68) a plurality of axially spaced cartridges (12) closed on one side with a rigid, perforated inner jacket (14) and an outer jacket (16) designed to be gas-permeable with low resistance as a carrier with the active material for catalysis, Adsorption or conversion of organic dusts and aerosols in gas are arranged.

2. Device according to claim 1, characterized in that the cartridges (12) with the supports for catalysis, adsorption and conversion of organic dusts and aerosols into gas are each arranged in separate housings (68) or units.

3. Device according to claim 1 or 2, characterized gekenn¬ characterized in that the outer casing (16) is constructed of active material or coated with it.

4. Device according to one of claims 1 to 3, characterized in that the cartridges (12) are combined to form at least one removable insert (70) or removable modules (10) each with individually releasably attached cartridges (12) .

5. Device according to one of claims 1 to 4, characterized characterized in that the cartridges (12) which are closed downstream are screwed on the gas outlet side to a cartridge holder (24) which is open in the area between the cartridges, on the gas inlet side are held or screwed to a cartridge holder (38) which is open in the area of the cartridges.

6. Device according to one of claims 1 to 5, characterized in that the cartridges (12) upstream with play from a preferably multi-part clamping piece (40, 42) are included, which on a between the clamping piece (40, 42) and the cartridge holder (38) inserted seal (44) acts and seals the interior (26) outside the cartridges (12).

7. The device according to claim 6, characterized in that the clamping piece (40, 42) is substantially strip-shaped, with substantially semicircular recesses (60) for the cartridges (12) is formed.

8. Device according to one of claims 1 to 7, characterized in that a closure cap (20) placed downstream over the inner casing (14) of the cartridges (12), upstream of a flange sleeve (30) serves to fasten the cartridges (12), wherein The sealing cap (20) and flange sleeve (30) are preferably connected to the inner jacket (14) by spot welding.

9. The device according to claim 8, characterized in that the outer jacket (16) is fixed gas-tight on the closure cap (20) and the flange sleeve (30) with clamping clips (34).

10. Device according to one of claims 1 to 9, characterized in that the holding and supporting parts, in particular the inner casing (14) of the cartridges (12) and Cartridge holder (24, 38) consist of high-alloy steel.

11. The device according to one of claims 1 to 10, characterized in that the inner casing (14) of the cartridges (12) has round (58) and / or elongated holes or is designed as a wire or ribbon grid.

12. Device according to one of claims 1 to 11, characterized in that the active material from a single material coating or a mixture of noble metals or of noble metal oxides, in particular of platinum, rhodium, palladium, vanadium, cobalt or their oxides with other metals or. whose oxides exist.

13. Device according to one of claims 1 to 12, characterized in that the carrier or the outer casing (16) of the cartridges (12) consists of fibers, in particular of knitted, woven or braided fibers made of activated carbon, ceramic or glass.

14. Device according to one of claims 1 to 13, characterized in that the modules (10) are sealed against one another with an elastic glass fabric seal.