METHOD FOR MANUFACTURING A PHOTOCATALYTIC DEVICE, PHOTOCATALYTIC DEVICE, PHOTOCATALYTIC COMPOSITION AND GAS DEPOLLUTING APPARATUS

Abstract

The invention refers to a method for manufacturing a catalytic device, with the steps: a) providing a first catalyst having photocatalytic activity, a second catalyst, which is a different molecule than the first catalyst, and an adsorbent, each in a powdered state, b) mingling the first catalyst, the second catalyst and the adsorbent to form a catalytic composition and suspending them in a suspension liquid to form a slurry, and c) repeatedly coating the slurry onto a solid grid-like carrier having a plurality of through holes, configured to allow a gas to flow through the carrier, and evaporating the suspension liquid.

Claims

1. A method for manufacturing a catalytic device, comprising: a) providing a first catalyst having photocatalytic activity, a second catalyst which is a different molecule than the first catalyst, and an adsorbent, each in a powdered state, b) mingling the first catalyst, the second catalyst and the adsorbent to form a catalytic composition and suspending the catalytic composition in a suspension liquid to form a slurry, and c) repeatedly coating the slurry onto a solid grid-like carrier having a plurality of through holes, wherein the carrier configured to allow a gas to flow through the carrier, and evaporating the suspension liquid.

2. The method according to claim 1, wherein the through holes account for at least 80% of a volume of the carrier.

3. The method according to claim 1 wherein the slurry is binder-free.

4. The method according to claim 1 wherein the slurry is coated onto the carrier via spray-coating.

5. The method according to claim 1 wherein the first catalyst is titanium dioxide.

6. The method according to claim 5, wherein the titanium dioxide is in a form of a mixture of anatase and rutile with an anatase/rutile ratio between 60/40 and 99/1.

7. The method according to claim 1 wherein the second catalyst is a low-temperature catalyst.

8. The method according to claim 1 wherein the adsorbent is a zeolite.

9. The method according to claim 1 wherein the providing step provides in weight percent with regard to their total mass: between 27% and 30% of the first catalyst, between 11% and 17% of the second catalyst, and between 55% and 59% of the adsorbent.

10. A catalytic device obtained by a method according to claim 1.

11. A catalytic composition, comprising in weight percent with regard to its total mass and each in a powdered state, between 27% and 30% of a first catalyst having photocatalytic activity, between 11% and 17% of a second catalyst which is a different molecule than the first catalyst, and between 55% and 59% of an adsorbent.

12. The catalytic composition according to claim 11, wherein the first catalyst is titanium dioxide the second catalyst is manganese monoxide and the adsorbent is a zeolite.

13. The catalytic composition according to claim 11, wherein the adsorbent is a synthetic hydrophilic zeolite of type A.

14. The catalytic composition according to claim 11, wherein the first catalyst is photo-activated.

15. The catalytic composition according to claim 11, being a non-thermal catalyst, and comprising, in weight percent with regard to its total mass: between 27% and 30% of photo-activated titanium dioxide as the first catalyst, between 11% and 17% of manganese monoxide as the second catalyst, between 55% and 59% of synthetic hydrophilic zeolite of type A as the adsorbent.

16. A gas depolluting apparatus, comprising a catalytic device according to claim 10 and/or a catalytic composition comprising in weight percent with regard to total mass and each in a powdered state, between 27% and 30% of a first catalyst having photocatalytic activity, between 11% and 17% of a second catalyst which is a different molecule than the first catalyst, and between 55% and 59% of an adsorbent coated onto a carrier, wherein the catalytic device and/or the catalytic composition is at least partially provided within a designated flow path of gas to be depolluted.

17. The gas depolluting apparatus according to claim 16, further comprising at least one source of UV radiation arranged in the designated flow path and configured to irradiate the catalytic composition and/or the catalytic device in order to activate the first catalyst.

18. The gas depolluting apparatus according to claim 17, wherein the at least one source of UV radiation is arranged in the designated flow path and the catalytic device or catalytic composition is arranged upstream and a second catalytic device identical to the catalytic device or a second catalytic composition identical to the catalytic composition is arranged downstream of the at least one source of UV radiation.

Description

[0156] Embodiments of the invention will be explained with respect to the attached figures.

[0157] FIG. 1 shows a perspective view onto an embodiment of carrier for a catalytic device,

[0158] FIG. 2 shows a perspective section of the carrier of FIG. 1 in a coated state, thereby forming an embodiment of a catalytic device,

[0159] FIG. 3 shows an exploded view of a partially assembled depolluting unit of an embodiment of the gas depolluting apparatus, and

[0160] FIG. 4 shows a perspective view of the assembled depolluting unit from FIG. 3.

[0161] In FIG. 1, a perspective view onto a solid grid-like carrier 2 is shown. The dotted lines indicate, that only a section of the complete carrier is depicted. The carrier 2 is designed as a honeycomb panel, which preferably is formed from sheets being corrugated to form combs 4. The sheets are preferably made of an inert material such as aluminum. Each comb 4 forms a through hole 6, which allows a gas to flow through the carrier 2.

[0162] The carrier 2 has a longitudinal axis L, along which the length of the combs 4 extends. The combs 4 each have a hexagonal cross section, which preferably remains constant along their length. Correspondingly, the through holes 6 also have a hexagonal cross section.

[0163] In FIG. 2 a section of a carrier 2 as shown in FIG. 1 is shown in a coated state, thereby forming a catalytic device 8. One comb 4 is depicted with two hinted sidewalls of adjacent combs 4. In the coated state, the surface of the carrier 2 is almost, preferably completely coated with the first catalyst, the second catalyst and the adsorbent.

[0164] However, in FIG. 2, the coating 10 is depicted only on the edges of the combs 4 for clarity reasons. Notwithstanding this, the coating 10 is also applied to the inner surfaces 12 of the combs 4 as well as to the outer surfaces 14 of the combs 4, which—aside from the side ends of the carrier 2—form inner surfaces 12 of adjacent combs 4. The surfaces are coated with multiple layers to form a resulting layer having a thickness of preferably 100 μm to 250 μm.

[0165] FIG. 3 shows a partially assembled embodiment of a depolluting unit 16 of an embodiment of the gas depolluting apparatus. In one embodiment of the invention, the depolluting unit 16 is the gas depolluting apparatus. In another preferred embodiment, the gas depolluting apparatus comprises a housing, which defines a designated flow path for the gas to be depolluted. The depolluting unit 16 is then arranged within this designated flow path.

[0166] The depolluting unit 16 comprises two catalytic devices 8, of which only one is depicted in FIG. 3, with carriers 2 that are coated with the first catalyst, the second catalyst and the adsorbent. The carriers 2 are each formed from honeycomb panels, which are encased by a carrier housing 18 on their side ends. When the carriers 2 are encased in a carrier housing 18, it is possible but not necessarily the case, that only those combs 4 and/or surfaces of the combs of the carrier 2 are coated, which are exposed to the environment and not covered by the carrier housing 18.

[0167] The depolluting unit 16 further comprises a UV radiation source 20, designed as an array of four UV radiation emitting lamps 22. Preferably these are lamps emitting UV-C radiation. The lamps 22 are arranged within a unit frame 24. The unit frame 24 preferably comprises sockets 26 for removably mounting the UV emitting lamps 22. Preferably the unit frame 24 furthermore comprises at least one power supply for the UV emitting lamps 22.

[0168] The unit frame 24 also comprises two receptacles 28 to accommodate the catalytic devices 8. In FIG. 3 the receptacles 28 are formed by the supporting surfaces 30, to which the carriers 2 and the carrier housings 18 are designed correspondingly. They are either simply positioned to lie on the supporting surfaces 30 or attached to the unit frame 24 via clamps or the like. In another embodiment, the receptacles 28 are designed as slots corresponding to the catalytic devices 8 being designed as slide-in-modules.

[0169] The gas to be depolluted flows through the carriers 2 and the UV radiation source 20 along the direction of flow F. Obviously, the direction of flow F, depending on the design of the gas depolluting apparatus, can also run in the opposite direction. The direction of flow F especially runs along the longitudinal axis L.

[0170] One advantage of the depolluting unit 16 being designed as depicted is, that the catalytic devices 8 and correspondingly the catalysts within the coating 10 of the carriers 2 are spatially very close to the UV radiation source 20. Therefore, the UV radiation can be used well for activating the photocatalyst, especially because on both sides of the UV radiation source 20 a catalytic device 8 is present. In addition, the waste heat of the lamps 22 can be used to enhance the catalytic activity of the second catalyst, which preferably is a low-temperature catalyst.

[0171] FIG. 4 shows the depolluting unit 16 in an assembled state with two catalytic devices 8, attached to the unit frame 24, each abutting the support surfaces 30 of the receptacles 28. It can be seen, that the dimensions of the catalytic devices 8 are corresponding to those of the unit frame 24.

REFERENCE SIGNS

[0172] 2 carrier [0173] 4 comb [0174] 6 through hole [0175] 8 catalytic device [0176] 10 coating [0177] 12 inner surface [0178] 14 outer surface [0179] 16 depolluting unit [0180] 18 carrier housing [0181] 20 UV radiation source [0182] 22 UV emitting lamp [0183] 24 unit frame [0184] 26 socket [0185] 28 receptacle [0186] 30 support surface