DE29703373U1 - Air purification device - Google Patents

Description

Applicant:

Mister

Dipl.-Ing. Uhiv. Arnold Scheel
Carron-du-Val-Str. 33

86161 Augsburg

Representative:

Patent attorneys

Dipl.-Ing. H.-D. Ernicke

Dipl.-Ing. Klaus Ernicke

Schwibbogenplatz 2b

D-86153 Augsburg

Date:

25.02.1997
929-9 he/sw

DESCRIPTION Air purification device

The invention relates to a device for cleaning the air of vehicle exhaust gases with the features in the preamble of the main claim.

Such a cleaning device is known from DE-A-39 29 521. Wires with a coating of palladium are used as reaction elements and are subjected to an electrical voltage. The catalyst wires are arranged in a specific orientation in several frames one behind the other in the cleaning device.

FR 2 657 542 discloses a filter for air purification consisting of an amorphous material and a zeolite. Nickel, palladium, platinum and other metals of group VIII can be used for a hydrogenation function.

Furthermore, JP 3-109924 (A) shows a catalyst with an inorganic porous body coated with palladium. JP 2-293020 (A) shows an air purifier with two activated carbon electrode plates containing palladium particles. The electrodes are subjected to voltage.

DE-A-95 05 211 discloses a device and a method for cleaning exhaust gases from exhaust gas extraction systems. The filter is preferably in fiber form, but can alternatively also be in granular form. Mixtures of different oxides are used as the filter material.

Another cleaning device for vehicles is known from DE-A-29 08 085. It has a catalyst for carbon monoxide, which consists of a sorption mass with a mixture of different metal oxides, such as manganese oxide, copper oxide, cobalt oxide and silver oxide. In addition, there are filters with calcium chloride and soda lime as well as an activated carbon filter. The sorption masses are used up. In practice, it has been shown that the known cleaning device is highly sensitive to moisture and also to temperature fluctuations in the air. It is therefore not sufficiently reliable in operation or requires an additional dehumidifier.

Similar cleaning devices are known from EP-A-0 160 010 or DE-A-28 19 702. They have the disadvantage that the air to be cleaned must be additionally treated, in particular preheated and then cooled, or that cleaning only takes place by adsorption or absorption. The known cleaning devices also have the disadvantage of low efficiency, which forces a reduction in the volume flow or an unreasonable increase in the size of the device. When reducing the volume flow, an increase in the proportion of recirculated air and multiple passes of the air to be cleaned are necessary.

A cleaning system for garages is known from DE-G 94 20 276. It contains a cleaning device with an adiabatically cooling air washer and a heat recovery device. 50% of the cleaned circulating air is returned to the room and mixed with fresh air. The other half is blown out as exhaust air via a chimney. This cleaning system is designed to condition the room air in a way that prevents fogging and is primarily designed for smaller rooms.

In larger spaces, especially long tunnels

In larger rooms, particularly long tunnels or garages, it is known to counteract exhaust gas problems by diluting the air. In tunnels, for example, the room air is extracted from the middle of the tunnel and blown out without being cleaned. Fresh air flows in from the front openings at the tunnel. The problem here is that the pollutant concentration at the extraction point must not exceed the legally permissible values. In order to meet the standards, very large quantities of air must be moved.

This results in very complex and costly facilities.

It is an object of the present invention to provide a more suitable cleaning device.

The invention solves this problem with the features in the main claim.

The palladium catalyst according to the invention has the advantage that it is insensitive to temperature and humidity. It allows constant use in a wide range of weather and climatic conditions. The palladium catalyst also makes it possible to oxidize and, if necessary, dispose of both nitrogen oxides and carbon monoxide in one device.

The cleaning device according to the invention is suitable both for non-stationary use in vehicles or the like, and for stationary use in permanent structures, e.g. rooms in buildings or the like. These are preferably largely closed rooms, in particular tunnels, garages, halls, etc.

The cleaning device according to the invention does not require any additional devices, such as heating and cooling devices or dehumidifiers, to function. Furthermore, no special air control measures, in particular no reductions in the volume flow, are required for its function.

-A-

required. The palladium catalyst can clean the air under the specified climatic conditions and works in all climatic conditions common in civilized areas. It has an essentially constant level of efficiency. It can also work with high volume flows, which is particularly advantageous for ventilating larger rooms.

The palladium catalyst has the additional advantage that it can regenerate itself from a wet or moist state automatically and without additional heating and release the moisture.

The spherical shape, the loose packing, the different grain sizes and the multi-stage nature of the catalyst are advantageous for the function and efficiency, especially with regard to the pressure drop.

The cleaning device advantageously has several different cleaning units and, in addition to the oxidation stages, also has dust filters and, in particular, an activated carbon unit. The latter can be used to specifically filter hydrocarbons such as benzene, phenols, etc. from the room air. In particular, nitrogen dioxide is also filtered out. In this respect, it is advantageous to arrange an activated carbon filter in the flow direction behind the oxidation catalyst.

The cleaning device according to the invention has the advantage that it works highly effectively and is particularly small. Thanks to its modular design, it can be optimally adapted to the respective requirements and is also particularly easy to maintain. It is particularly economical compared to previously known devices.

.&Ggr;.

The invention also allows rooms to be cleaned zone by zone using several cleaning devices, which means that the concentration of pollutants and the amount of air moved can be kept low. The majority of the cleaned air is returned to the room, meaning that only relatively small amounts of fresh air are required and only relatively small amounts of exhaust air need to be removed. As a result, significantly less air needs to be moved than with the current technology in order to comply with the pollutant limits.

The reduction in air volume significantly reduces the construction effort, especially in tunnels. Despite the arrangement of several cleaning devices, the cleaning system according to the invention is significantly cheaper in terms of production costs than previously known exhaust air systems. In addition, the maintenance and operating costs are significantly lower than with the state of the art.

Cleaning in zones also makes it possible to adapt the cleaning intensity to the amount of pollutants and to circulate and clean the air more intensively in places where it is loaded with higher levels of pollutants. This enables further optimization of the construction and cost expenditure in order to be able to comply with the pollutant limits at all relevant points in the room.

The cleaning system according to the invention has particular advantages in long spaces, such as tunnels or long garages. Zone cleaning has particularly beneficial effects here. Other advantageous areas of application are halls for vehicle sports, e.g. go-karts, motorcycle trials, etc.

Within the zones, there is essentially a largely local air circulation and cross ventilation directed perpendicular to the longitudinal axis of the room, which leads to a

The optional central measuring and control option is also a particular advantage, whereby the cleaning devices can also have their own measuring and control devices.

For long rooms, especially tunnels etc., there is a particularly beneficial effect in that the tunnel length can be as long as desired thanks to zone cleaning. In the previously known exhaust air systems, the tunnel length was actually limited due to the legal restriction on the amount of air moved in conjunction with the pollutant limit values.

Further advantageous embodiments of the invention are specified in the subclaims.

The invention is illustrated by way of example and schematically in the drawings. In detail,

Figure 1: A tunnel section in side view

with zone-wise cleaning by several cleaning devices,

Figure 2: A perspective view of the &iacgr;&ogr; cleaning device and

Figure 3: a cleaning device in a vehicle.

Figure 1 shows a detail and a side view of an elongated room (2), e.g. a tunnel, through which vehicles with combustion engines travel. The room air (4) laden with combustion gases and their pollutants is treated by a cleaning system (1). The combustion gases are distributed in the room air (4). The pollutant concentration in the room (2) is usually below 250 ppm and the air temperature below 5O ⁰ C. The relative humidity can vary freely between 0 and 100%.

As Figure 1 shows, the cleaning system (1) consists of several cleaning devices (9) which are preferably evenly distributed in the room (2) which is divided into zones (3). The tunnel (2) shown is divided along its axis (22) into a series of zones (3) which, for example, have a length of approx. 100 m. In or on each zone (3) there is a cleaning device (9). The cleaning devices (9) are arranged close to the place where the exhaust gases originate. They are located either in the room

(2) or outside in the vicinity of the room (2). They are housed, for example, in niches or bays, cross tunnels or the like. They are connected via a suitable

Air duct connected to the room (2).

The cleaning devices (9) can each be individually provided with devices for supplying fresh air (5) and/or for removing cleaned or uncleaned exhaust air (6). Such a fresh air and exhaust air device can alternatively also be provided centrally for the room (2). It is also possible to arrange the fresh air and exhaust air device(s) (5,6) separately from the cleaning device(s) (9). In addition, the cleaning system (1) can be combined with a smoke extraction device (25).

The cleaning devices (9) suck in the polluted room air (4) and clean it of the pollutant components. The majority of the cleaned air, i.e. more than 50%, is returned to the zone (3) as supply air (7) and refreshed if necessary. Preferably, approx. 70-80% of the room air (4) is returned after cleaning, whereby 30-20% fresh air (5) is added to the supply air (7) and a corresponding proportion of exhaust air (6) is discharged. The exhaust air (6) is preferably cleaned. In addition, uncleaned room air (4) can also be sucked in and discharged as exhaust air (6). Due to the small amounts of fresh air and exhaust air, the pipes and ducts can be relatively small.

The fresh air and exhaust air (5,6) can be supplied and discharged from and to the outside in one or more cavities (23) of a double-shell tunnel wall. Alternatively, they can be guided in chimneys (24), small branch ducts or in any other suitable air duct system. The supply and exhaust air lines (5,6) can be connected to the cleaning devices (9). Figure 1 illustrates this arrangement in the left half of the picture with a chimney connection on the outlet side. Alternatively, other

Arrangements possible. The right half of the picture shows a variant with a fresh air supply (5) opening separately into the zone (3) and an exhaust air line (6) connected to the outlet side of the cleaning device (9).

By cleaning the room air in zones (4), an accumulation of pollutants over the length of the tunnel is prevented. The tunnel (2) can therefore be as long as desired. Within the zones (3), a largely local air circulation or cross ventilation preferably takes place. However, air exchange can take place between the zones (3). The zones (3) can also be divided by structural measures, although this is not necessary.

The cleaning system (1) can have a central measuring and control device (8) with which, for example, the pollutant content in the room air (4) is measured at a point with a particularly high concentration and the cleaning devices (9) are controlled accordingly. The measuring device can be used to selectively measure individual pollutant contents, e.g. carbon monoxide. The control can include a regulating device that keeps the pollutant concentration at a predeterminable value by appropriately wiring the cleaning devices (9).

Figure 2 shows a cleaning device (9) in detail. It preferably has several cleaning units (15,16,17,18,19), which are preferably constructed in the form of modules (21) and are arranged one behind the other in the air flow direction (12). The components are located in a common housing (10), in which a fan (11), a blower or the like is preferably arranged on the output side.

· I

- 10 -

Connection lines for fresh air (5) and exhaust air (6) can also be located here. The exhaust air line (6) is connected to the pressure side of the fan (11) and the fresh air line (5) is preferably connected to the suction side. The contaminated room air (4) enters the cleaning device (9) on the left-hand side in Figure 2 and leaves it on the opposite side as cleaned and possibly enriched with fresh air (5) recirculated air (7).

A separate measuring device (13) for air values such as pollutant content, temperature, humidity, etc. and a control or regulation device (14) can also be arranged on the output side.

The cleaning device (9) contains a cleaning unit (18) that oxidizes carbon monoxide to carbon dioxide. It can also oxidize nitrogen monoxide to nitrogen dioxide or other nitrogen oxides. The cleaning unit (18) is preferably a catalyst. The catalyst (18) has one or more reaction elements that are coated at least in some areas with preferably pure palladium. The palladium catalyst (18) is particularly advantageous for the prevailing low temperatures and the varying humidity values.

The catalyst (18) can be designed in different ways. It can also comprise several stages connected in parallel or preferably in series. It consists, for example, of several hollow plates (20) arranged in a zigzag shape, which are inclined relative to the air flow (12) and offer a large area through which the air can flow or a large volume. The hollow plates

(20) are permeable to air and have, for example, perforated walls. They contain reaction particles that are preferably spherical and have different grain sizes, e.g.

2, 3 and 4 mm. The particles are in the form of a loose, dry bed through which the room air (4) drawn in at the beginning flows. Alternatively, instead of the hollow plates (20), any other hollow bodies or other suitable constructions can be present, e.g. filter cartridges etc.

The reaction particles consist of a suitable carrier material and a coating or coating of palladium. The carrier material can be any material. It is preferably a metal oxide, in particular aluminum oxide. The palladium coating can be applied in any suitable manner, e.g. by vapor deposition.

In the preferred embodiment of the cleaning device (9), there are one or two suitable dust filters on the inlet side, which in Figure 2, for example, are a folded mat-shaped pre-filter (15) and a downstream fine filter (16). This can be followed by an activated carbon filter (17) with a large number of longitudinally aligned cylindrical filter cartridges. This is followed by the catalyst (18).

The activated carbon filter (17) can additionally or alternatively be arranged behind the catalyst (18). A cleaning unit (19) for the disposal of the oxidized nitrogen oxides can be connected to the catalyst (18). This could also be the activated carbon filter mentioned. In the preferred embodiment, the catalyst (18) has two or more stages. The palladium catalyst can also form the cleaning unit (19).

The housing (10) is relatively small and has a length of approx. 4.6 m and a height and width of approx. 1.5 m each. The cleaning device (9) can be transportable

- 12 -

and have a container design. The housing dimensions can be based on standard container dimensions, but also on the dimensions and equipment of demountable containers, etc.

The fan (11) is designed for a throughput of approx. 10,000 m ³ /h. This design refers to a zone size of approx. 100 m for a tunnel (2). The design values can vary as appropriate. The oxidation of carbon monoxide takes place in the catalyst (18) with an efficiency of approx. 80%. Nitrogen monoxide is oxidized to more than 40%.

Figure 3 shows another application area for the cleaning device (9). It is installed in a vehicle (26). In this case, the cleaning device (9) is particularly small and can be integrated into the vehicle's ventilation system. It cleans the exhaust-containing room or outside air (4) supplied from the outside via the engine compartment and the ventilation slots and releases cleaned circulating air or supply air (7) into the vehicle interior. The air in the vehicle can also circulate, so that air (4) from the vehicle interior is also fed into the cleaning device (9) for cleaning.

For use in vehicles, the cleaning device (9) can have fewer components. For example, the dust filters (15, 16) and, if necessary, the activated carbon filter (17) can be omitted. These components can also be present separately as components of the existing vehicle ventilation and arranged outside the cleaning device (9). In the simplified embodiment, the cleaning device (9) then consists only of the catalyst (18) and, if necessary, the cleaning unit (19). The fresh air and exhaust air lines (5, 6) can also be omitted in this design variant. The fan (11) can

:: ^5S

- 13' -

as in the previously described embodiment, it can be integrated into the cleaning device (9). However, it can also be arranged separately as a vehicle component.

The cleaning device (9) can be arranged at any suitable location in the vehicle (26), e.g. in the intake tract in the area of the front of the vehicle or the dashboard. Alternatively, it can also be arranged in the trunk or at another suitable location.

Modifications to the embodiment shown are possible in various ways. Firstly, the cleaning unit for the oxidation of carbon monoxide and nitrogen monoxide can be designed differently. The activated carbon filter can be omitted or arranged elsewhere or designed differently. The other cleaning units are also variable and can be adapted to the different environmental conditions. Dust filtering can, for example, take place elsewhere and in a different way, e.g.

through ionization etc. The design and arrangement of the fan and the entire housing or modular construction can also be changed.

- 14 LIST OF REFERENCE SYMBOLS

1 cleaning system

2 rooms, tunnel, underground parking

3 Zone

4 Indoor air, outside air (vehicle)

5 Fresh air

6 Exhaust air

7 Recirculated air, supply air (vehicle)

8 Measuring and control equipment

9 Cleaning device

10 Housing

11 Fan

12 Air flow, flow direction

13 Measuring device

14 Control

15 Cleaning unit, pre-filter

16 Cleaning unit, fine filter

17 Cleaning unit, activated carbon filter

18 Cleaning unit, catalyst

19 Cleaning unit, NO _x disposal

20 hollow panels

21 Module

22 spatial axis

23 Cavity

2 4 Fireplace

25 Smoke extraction

2 6 Vehicle

Claims (1)

■5 O. Ci &kgr;· &Ogr;:'··: - 15 CLAIMS FOR PROTECTION 1.) Device for cleaning the air of vehicle exhaust gases with low temperature and concentration, the cleaning device being equipped with a palladium-containing catalyst, characterized in that the catalyst (18) has grain-shaped reaction elements with a coating or casing made of palladium, the catalyst (18) having a plurality of hollow bodies (20) through which the room air (3) can flow and with a loose bed of reaction elements in the interior. 2.) Device according to claim 1, characterized in that the catalyst (18) has several hollow bodies (20) through which the room air (3) can flow and with a loose bed of reaction elements in the interior. 3.) Device according to claim 1 or 2, characterized in that the catalyst (18) has two or more stages. 4.) Device according to claim 1 or one of the following, characterized in that the cleaning device (9) has several cleaning units (15, 16, 17, 18, 19). 5.) Device according to claim 4, characterized in that the cleaning units (15, 16, 17, 18, 19) are arranged one behind the other in a series connection in the flow direction (12). - 16 - 6.) Device according to claim 4 or 5, characterized characterized in that the cleaning device (9) has a cleaning unit (19) for the disposal of NC _x , in particular NC2.
5 7.) Device according to claim 4 or one of the following, characterized in that the cleaning device (9) has one or more cleaning units (17) with activated carbon. 10 8.) Device according to claim 7, characterized in that the activated carbon (17) is arranged in the flow direction (12) in front of and/or behind the catalyst (18). 9.) Device according to claim 4 or one of the following, characterized in that the cleaning device (9) has several dust filters (15,16).
20 10.) Device according to claim 4 or one of the following, characterized in that the cleaning units (15, 16, 17, 18, 19) are designed as modules (21). 11.) Device according to claim 10, characterized in that the modules (21) are arranged in a common transportable housing (10). 12.) Device according to claim 1 or one of the following, characterized in that the cleaning device (9) has a fan (11), measuring device(s) for the air values and a control (14). 13.) Device according to claim 1 or one of the following, characterized in that the cleaning device (9) has one or more connections for fresh air (5) and/or exhaust air (6). .) Device according to claim 1 or one of the following, characterized in that the cleaning device (9) in a vehicle (26) or in a largely closed room (2), &iacgr;&ogr; in particular a tunnel, a garage or a hall. 15.) Device according to claim 14, characterized in that several cleaning devices (9) are arranged in a cleaning system (1) distributed in zones (3) of the room (2). 16.) Device according to claim 14 or 15, characterized in that the cleaning devices (9) are arranged in the room (2) or outside in the vicinity of the room (2). 17.) Device according to claim 14, 15 or 16, characterized in that the cleaning system (1) has a central measuring and control device (8).