Air purification device and process

Abstract

A device and a process used to purify air from pollutants are disclosed. The device has at least one empty body defining a chamber intended to receive an air flow to be purified and having at least one inlet hole for the air, and at least one outlet hole for the air. The chamber has an electric field generator, at least one photocatalyst, intended to be excited by a luminous radiation, implementing a photocatalysis process, at least one luminous radiation source intended to excite the photocatalyst, and at least one adsorbing material. The electric field generator, the at least one photocatalyst and the at least one adsorbing material are disposed in the chamber in such manner to cooperate.

Claims

1. An apparatus for purifying air from pollutants, the apparatus comprising: at least one empty body defining a chamber adapted to receive an air flow to be purified, the at least one empty body having at least one inlet hole and at least one outlet hole for the air flow, the chamber comprising: an electric field generator internal of the chamber; a luminous radiation source internal of the chamber; a photocatalyst adapted to be excited by luminous radiation from said luminous radiation source so as to cause photocatalysis; a plurality of walls formed of an absorbent material, each of said plurality of walls lying on a plane, wherein said electric field generator and said photocatalyst and said plurality of walls are cooperative with each other internal of the chamber, wherein said plurality of walls are disposed radially around said photocatalyst such that the planes of said plurality of walls converge toward said photocatalyst, said plurality of walls defining a plurality of spaces within the chamber, the at least one inlet hole and the at least one outlet hole being arranged such that the air flow enters the chamber in correspondence to the convergence of the planes of said plurality of walls and passes through the plurality of plurality of spaces and passes outward of the at least one empty body through the at least one outlet hole.

2. The apparatus of claim 1, wherein said photocatalyst comprises a composite material having a photocatalytic material applied on at least a portion of an adsorbing material of said photocatalyst.

3. The apparatus of claim 1, wherein said photocatalyst is disposed on at least one conductive element.

4. The apparatus of claim 1, wherein said electric field generator comprises a first electrode and a second electrode, said photocatalyst being disposed on at least one of the first and second electrodes.

5. The apparatus of claim 1, wherein at least a portion of said plurality of walls comprises activated carbon.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) Additional features and advantages of the present invention will be more evident from the following description, which has a merely illustrative, not limiting purpose, with reference to the following diagrammatic drawings, wherein:

(2) FIG. 1 is a plan view of a possible embodiment of the device according to the invention (the device of FIG. 1 is seen from the side from which air is introduced in the device);

(3) FIG. 2 is a side view of the same embodiment of the device according to the invention shown in FIG. 1 (the device is seen orthogonally with respect to the discharge electrode (a wire in this case));

(4) FIG. 3 is a second side view of the same embodiment of the device according to the invention shown in FIG. 1 and in FIG. 2 (the device is seen in parallel direction with respect to the discharge electrode (a wire in this case));

(5) FIG. 4 is a diagrammatic drawing of the synergetic connections between the different purification techniques obtained by means of the device and the process of the invention.

EMBODIMENTS OF THE INVENTION

(6) FIG. 1 shows an air purification device 1 according to the present invention.

(7) Said device 1 is formed of an empty body 70 that defines a chamber 60 (see for example FIG. 2) suitable for receiving an air flow to be purified.

(8) According to an embodiment of the present invention, the empty body of the device comprises a horizontal upper side (that is to say a wall) 70a and a horizontal lower side 70b parallel to the horizontal upper side. The empty body also comprises a lateral side 70c, for example in the case of an empty body having a substantially cylindrical shape, or can comprise more than one lateral side to form an empty prismatic body. The at least one lateral side (wall) is substantially perpendicular to the two horizontal sides, and suitable for connecting said horizontal upper and lower sides. According to a possible embodiment, such as the one shown for example in the attached figures, the empty body 70 is shaped as a parallelepiped having two parallel upper and lower sides (walls) 70a, 70b and four lateral sides (walls) 70c.

(9) Specifically, according to the embodiment shown in the figures, the empty body 70 comprises four lateral walls 70c that extend between the two upper and lower walls 70a, 70b with square shape.

(10) As mentioned above, the shape of the empty body 70 of the device is not limited to this embodiment. In fact, other shapes of the empty body 70 are possible, for example, a prismatic and a cylindrical shape, on condition that a chamber is formed inside the empty body, preferably a single chamber intended to receive the air flow to be purified.

(11) As illustrated in detail below, one of the two horizontal sides, such as for example the upper side 70a, is provided with at least one inlet hole 40, preferably a plurality of inlet holes that let the air to be purified in.

(12) According to a preferred embodiment of the present invention, such an upper side is provided with a fan 41, or similar means for forcedly introducing air inside the empty body, which is preferably positioned inside the chamber, and more preferably inside the chamber in correspondence of the inlet holes of the air. Therefore, air can be introduced in the device thanks to the fan, which generates an incoming air flow.

(13) Specifically, as shown in FIGS. 1-3, the air flow to be purified is generated by extracting the air with a fan 41 from the space and is introduced in the device 1 from suitable inlet holes 40 obtained on the side 70a of the empty body 70 of the device 1 where the fan 41 is provided.

(14) According to a preferred embodiment, at least one lateral side (wall), preferably all lateral sides, of the empty body of the device have at least one outlet hole 50, preferably a plurality of outlet holes that let the air out.

(15) In view of the above, the air is introduced in the device according to an incoming air flow, which is substantially perpendicular to the two upper and lower sides 70a, 70b, and comes out of the device through the outlet holes 50, from the lateral walls 70c, according to one or more outgoing flows; said outgoing flows being substantially perpendicular, preferably perpendicular and radial, with respect to the incoming flow.

(16) Means for generating an electric field 20, a photocatalyst 10, a luminous radiation source 11 and an adsorbing material 11 are provided inside the device 1.

(17) In particular, according to the embodiment of FIG. 1, the means for generating an electric field 20 comprise a metal wire 20a that passes through the chamber inside the device 1 and is tensioned between two supports 21. Said metal wire 20a acts as discharge electrode for actuating the electrofiltration process (that is to say electrostatic precipitation) of the air introduced in the device 1.

(18) Although not shown in the figures, the device comprises a suitable power supply to supply the necessary voltage to the metal wire.

(19) According to the embodiment shown in FIG. 1, the metal wire 20a (that is to say the discharge electrode) is positioned between a luminous radiation source 11 and the photocatalyst 10.

(20) FIG. 1 shows an embodiment wherein the luminous radiation source 11 is a UV lamp 11a that is maintained in position inside the chamber by the support means 12. According to a possible embodiment, the photocatalyst comprises a composite material 10a with photocatalytic and adsorbing properties. Specifically, according to a possible embodiment, the photocatalyst 10 is a sheet of composite material 10a comprising a photocatalytic material (for example titanium dioxide TiO2) applied on at least part of an adsorbing material (for example active carbon).

(21) As mentioned above, according to a possible embodiment, the device comprises a conductive material. For example, the photocatalyst 10 may comprise a composite material with conductive properties.

(22) It must be noted that a photocatalyst material can be applied on the conductive material (for example graphite) and/or on an adsorbing material.

(23) According to a possible embodiment, the photocatalyst 10 comprising a composite material with photocatalytic, adsorbing and conductive properties (diagrammatically indicated in the figures with reference 10a) can correspond to the collecting electrode for the electrofiltration process.

(24) As known, although not shown in the attached figures, also the collecting electrode is suitably connected to the power supply that provides the necessary voltage to generate a potential difference between the two (discharge and collecting) electrodes. According to other embodiments, if the photocatalyst has no conductive properties, the composite material with adsorbing and photocatalytic properties can be positioned on an electrode, for example a plate of metallic material acting as electrode.

(25) An adsorbing material 30 can be seen in the embodiment of FIG. 1; in particular, a plurality of walls (filters) of adsorbing material 30 can be seen, which are disposed radially with respect to the direction of the air flow introduced in the device 1.

(26) Specifically, such an adsorbing material 30 is disposed radially with respect to the axis that perpendicularly intercepts the two horizontal upper and lower sides of the device 1; according to the embodiment shown in FIG. 1, such an axis is orthogonal to the metal wire 20a and to the plane whereon the plate of adsorbing, photocatalytic and conductive material 10a is placed.

(27) Such a plurality of walls (filters) of adsorbing material 30 defines a plurality of spaces 31 inside the chamber of the device 1, which are intended to convey the air flow between the walls of adsorbing material 30. Then the air flow comes out of the device 1 passing through the outlet holes 50 provided on the lateral walls 70c of the empty body 70 of the device 1. According to a possible embodiment, as shown in the attached figures, the walls (filters) of adsorbing material are disposed in such manner to be perpendicular to the upper and lower sides (walls) 70a, 70b.

(28) According to the embodiment of FIG. 1, the lateral walls 70c are disposed in orthogonal position with respect to the side of the empty body 70 of the device 1 whereon the fan 41 is provided, that is to say with respect to the side of the empty body from which the air flow is introduced. According to the embodiment of FIG. 1, the outlet holes 50 are provided on the lateral walls 70c of the empty body 70 of the device 1, in correspondence of the spaces 31 defined by the walls of adsorbing material 30.

(29) As illustrated above, the air to be purified is extracted with a fan 41 from the space and is introduced in the device 1 from suitable inlet holes 40 obtained on the side (wall) 70a of the empty body 70 of the device 1 whereon the fan 41 is provided.

(30) The air flow is conveyed towards the photocatalyst, and in particular towards the adsorbing, photocatalytic and conductive material 10a, which is subject both to the electric field generated by the metal wire 20a (whereon an electric potential is applied), and to the UV light coming from the UV lamp UV 11a.

(31) As mentioned above, according to a possible embodiment, the adsorbing, photocatalytic and conductive material 10a corresponds to the collecting electrode of an electrofilter (whose discharge electrode is the metal wire 20a).

(32) In this way, the electric field generated by the electrodes (i.e. in this case the metal wire 20a and the adsorbing, photocatalytic and conductive material 10a) induces the collection of pollutants on the adsorbing, photocatalytic and conductive material 10a. The presence of the electrofilter generates ozone and increments the removal of the pollutants. The photocatalysis process by the adsorbing, photocatalytic and conductive material 10a, which is activated by means of a UV lamp 11a, oxides the pollutants (moreover, titanium dioxide (TiO2) also reduces the presence of the ozone), partially regenerating the adsorbing, photocatalytic and conductive material 10a.

(33) The adsorbing material 30, disposed radially to the adsorbing, photocatalytic and conductive material 10a, holds and confines the primary and secondary pollutants inside the device 1. Outlet holes 50 are provided on the lateral walls of the empty body 70 to let the purified air out.

(34) FIG. 2 shows a side view of the device 1 of the invention shown in FIG. 1. The device 1 is seen laterally, orthogonally with respect to the metal wire 20a that represents the discharge electrode of the electrofilter.

(35) FIG. 2 shows the chamber 60, which is intended to receive an air flow to be purified, defined by the empty body 70 of the device 1.

(36) As mentioned above, the incoming air flow 42 is generated by extracting the air with a fan 41 from the space and is introduced in the chamber 60 from suitable inlet holes 40 obtained on the side 70a of the empty body 70 of the device 1 whereon the fan 41 is provided.

(37) With reference to FIG. 2, the chamber 60 contains a UV lamp 11a with relevant support means 12, a portion of the plate of adsorbing, photocatalytic and conductive material 10a; moreover, a portion of the metal wire 20a (that is to say the discharge electrode of the electrofilter) is disposed in intermediate position between these parts.

(38) FIG. 2 also shows the plurality of walls of adsorbing material 30; said walls are disposed in radial direction with respect to the incoming air flow 42. The side view of the device 1 shows the radial position of the walls (filters) of adsorbing material 30.

(39) For the sake of clarity, FIG. 2 shows the outlet holes 50 to let the purified air out, which are obtained on the lateral walls 70c of the device, in correspondence with the spaces between two walls of adsorbing material 30.

(40) FIG. 2 diagrammatically shows the outgoing air flow 51 that comes out from the holes 50 on the side walls of the empty body 70 of the device 1 of the invention.

(41) In such an embodiment, the air flow that is purified inside the device 1 comes out from the device with an orthogonal and radial direction with respect to the incoming direction.

(42) FIG. 3 shows a second side view of the same embodiment of the device 1 according to the invention shown in FIG. 1 and in FIG. 2. The device is seen in parallel direction with respect to the metal wire 20a that forms the discharge electrode (for the implementation of the electrostatic precipitation process).

(43) Also FIG. 3 shows the chamber 60, which is intended to receive an air flow to be purified, defined by the empty body 70 of the device 1.

(44) The same figure also shows the fan 41 and the inlet holes 40 to introduce the air inside the chamber 60 of the device 1.

(45) The chamber 60 contains the UVA lamp 11a with relevant support means 12, the plate of adsorbing, photocatalytic and conductive material 10a (of which only small portions are visible in FIG. 3) and the metal wire 20a (that is to say the discharge electrode of the electrofilter) disposed in intermediate position between the UV lamp 11a and the plate of adsorbing, photocatalytic and conductive material 10a. The metal wire 20a passes through the chamber inside the device 1, being tensioned between the two supports 21 (only one support 21 is visible). The metal wire 20a is shown as a point because of the point of observation in lateral parallel position to the metal wire 20a.

(46) A plurality of walls of adsorbing material 30 is disposed radially with respect to the direction of the incoming air flow 42, not shown in FIG. 3.

(47) As shown in FIG. 2, for the sake of clarity, also FIG. 3 indicates the outlet holes 50 that are used to let the purified air out. The outlet holes 50 are obtained on the lateral walls (sides) of the device, in correspondence of the spaces 31 (not shown in FIG. 3) between two walls of adsorbing material 30.

(48) According to the embodiment of the device 1 of the invention, as shown in FIGS. 1, 2 and 3, the outlet holes 50 used to let the purified air out are provided on the four lateral walls 70c of the device 1. However, other configurations are possible.

(49) In conclusion, in the device 1 and in the process according to the present invention, a fan 41 or similar means for forcedly introducing the air inside the device generates an air flow that is introduced in the chamber 60 defined by the empty body 70 of the device through the inlet holes 40.

(50) The air flow reaches the photocatalyst and in particular the adsorbing, photocatalytic and conductive material 10a. In such a case, the adsorbing, photocatalytic and conductive material corresponds to the collecting electrode of an electrofilter, so that the electric field induces the collection of pollutants on said adsorbing, photocatalytic and conductive material and on the walls of adsorbing material.

(51) As mentioned earlier, the discharge electrode of the electrofilter is, for instance, a metal wire 20.

(52) The presence of the electrofilter generates ozone and increments the elimination of pollutants. The photocatalysis process by the photocatalyst, which is activated by means of a suitable luminous source, for example, a UV lamp 11a, oxides the pollutants, at least partially regenerating the adsorbing, photocatalytic and conductive material, and the walls (filters) of adsorbing material (for example composed of active carbon).

(53) Preferably, the adsorbing, photocatalytic and conductive material 10a reduces the presence of the ozone generated by the action of the electric field. The adsorbing material 30, for example of the active carbon walls, encloses the primary pollutants (the pollutants that are introduced directly in the space because of the process that produced them) and the secondary pollutants (that is to say by-products of the reactions that take place on the primary pollutants) inside the device.

(54) FIG. 4 diagrammatically shows the synergetic connections between the different techniques implemented by the device of the invention.

(55) The three blocks, which are indicated as ESP, Photocatalyst and Adsorbing Material, diagrammatically indicate the three purification techniques used simultaneously according to the invention, that is to say the electrostatic precipitation (ESP block), the photocatalysis (Photocatalyst) and the adsorption (Adsorbing Material).

(56) The continuous lines indicate the effects of the single techniques, whereas the broken lines represent the connections created between the effects of the different techniques, diagrammatically showing how each of the electrostatic precipitation (ESP), the photocatalysis (Photocatalyst) and the adsorption (Adsorbing Material) has some effects that synergistically interact with the effects of the other techniques.

(57) For example, in FIG. 4 the effects of electrostatic precipitation (ESP) are summarized in: elimination of particulate, increment of the adsorbing capacity of the material (that is to say of the adsorbing material) and ozone generation.

(58) The effects of photocatalysis (Photocatalyst) are summarized in: oxidation of pollutants and destruction of the ozone.

(59) The effects of the third technique, that is to say adsorption (Adsorbing Material), are summarized in: adsorption of the pollutants and adsorption of the ozone.

(60) As shown in the diagram, the capacity of the adsorbing material to adsorb pollutants is incremented by the effects of the electric field used in the electrostatic precipitation. The electric field generates ozone inside the air treated with the electrostatic precipitation (electrofiltration) that is simultaneously destroyed by the photocatalytic action of the photocatalyst and/or adsorbed by the adsorbing material. It must be noted that the photocatalytic action can be also implemented at the level of the ozone already adsorbed by the adsorbing material.

(61) The interactions indicated in the diagram of FIG. 4 are only some of the several synergetic interactions that occur between the three techniques used in the invention.

(62) For example, the additional effects of the application of an electric field to the photocatalysis (specifically heterogeneous photocatalysis) are: increased efficiency of the catalytic process, generation of activated chemical species, and their confinement inside the device of the invention thanks to the adsorbing properties, which are in turn increased by the synergies between the processes.

(63) Moreover, the association of the photocatalysis (in particular heterogeneous photocatalysis) and of an electric field induced on a solid adsorbing material generates an interaction with a higher adsorbing capacity of the material, regenerating the adsorbing material thanks to the oxidation of the pollutants that are present at adsorbing material level caused by the photocatalysis.