阅读说明：本技术 用于减少气体混合物中的污染物的装置 (Device for reducing pollutants in a gas mixture ) 是由 吉奥瓦尼·巴迪 劳拉·尼科莱 奥利维亚·比托斯 马克·比托斯 西蒙妮·博纳里 于 2018-09-04 设计创作，主要内容包括：描述了一种用于减少气体混合物中的污染物的装置(1),所述装置(1)包括：容纳本体(2),容纳本体(2)具有用于气体混合物的入口部分(3)和用于气体混合物的出口部分(4),容纳本体(2)向气体混合物施加固定的流动方向(D)；至少一个过滤单元(10),过滤单元(10)包括光催化过滤器(7),光催化过滤器(7)沿着该固定的流动方向(D)介于第一光源(6a)和第二光源(6b)之间,第一光源(6a)和第二光源(6b)均具有可见光谱(400-700nm)内的波长,光催化过滤器(7)包括光催化纳米颗粒涂层,并且该纳米颗粒涂层包括掺杂有氮掺杂剂的二氧化钛；在过滤单元(10)之前用于矫直气流的单元(5)。(An apparatus (1) for reducing contaminants in a gas mixture is described, the apparatus (1) comprising: a containment body (2), the containment body (2) having an inlet portion (3) for the gas mixture and an outlet portion (4) for the gas mixture, the containment body (2) imparting a fixed flow direction (D) to the gas mixture; at least one filter unit (10), the filter unit (10) comprising a photocatalytic filter (7), the photocatalytic filter (7) being interposed along the fixed flow direction (D) between a first light source (6a) and a second light source (6b), the first light source (6a) and the second light source (6b) each having a wavelength within the visible spectrum (400-700nm), the photocatalytic filter (7) comprising a photocatalytic nanoparticle coating, and the nanoparticle coating comprising titanium dioxide doped with a nitrogen dopant; a unit (5) for straightening the air flow before the filter unit (10).)

1. An apparatus (1) for reducing pollutants in a gas mixture, comprising:

a containment body (2), the containment body (2) having an inlet portion (3) for the gas mixture and an outlet portion (4) for the treated gas mixture, the containment body (2) imposing a fixed flow direction (D) on the gas mixture,

at least one filtering unit (10), said filtering unit (10) comprising a photocatalytic filter (7), said photocatalytic filter (7) being interposed along said fixed flow direction (D) between a first light source (6a) and a second light source (6b), said first light source (6a) and second light source (6b) each having a wavelength within the visible spectrum, said photocatalytic filter (7) comprising a photocatalytic nanoparticle coating and said nanoparticle coating comprising titanium dioxide doped with a nitrogen dopant, said device (1) further comprising a unit (5) for straightening the gas flow of said gas mixture, said unit (5) being arranged before said at least one filtering unit (10).

2. The device (1) for reducing pollutants in a gas mixture according to claim 1, wherein the light source (6a, 6b) is not in direct contact with the gas flow of the gas mixture, because the light source (6a, 6b) is inserted inside a container (8), the container (8) being at least partially transparent to the visible light emitted by the light source (6a, 6 b).

3. The device (1) for reducing contaminants in a gas mixture according to claim 2, wherein there is an air gap (9) between the container (8) and the light source (6, 6a, 6 b).

4. Device (1) for reducing pollutants in a gas mixture according to claim 3, wherein inside the air gap (9) there is air having a pressure greater than the pressure of the gas flow of the gas mixture.

5. Device (1) for reducing pollutants in gaseous mixtures according to any of the preceding claims, wherein the inner surface of the containment body (2) is at least partially reflective to the visible light.

6. Device (1) for reducing pollutants in a gas mixture, wherein the photocatalytic filter (7) is made of a ceramic material and comprises at least one of cordierite, mullite, alumina.

7. An apparatus (1) for reducing contaminants in a gas mixture, wherein the nitrogen dopant is one of an ammine complex, an amide, an organic ammonium salt, an inorganic ammonium salt.

8. Device (1) for reducing contaminants in gas mixtures, wherein the coating according to claim 7 or 8 is obtained by in situ reaction at T >300 ℃.

9. Device (1) for reducing pollutants in a gas mixture, further comprising a recirculation circuit connecting said outlet portion (4) and said inlet portion (3) of said containment body (2).

10. Device (1) for reducing pollutants according to any one of the preceding claims, wherein said containment body (2) comprises a second inlet portion (11) for an oxidizing agent (12), said second inlet portion (11) being arranged before said at least one filtering unit (10).

11. Device (1) for reducing pollutants in a gas mixture according to claim 10, wherein said second inlet portion (11) is provided for mixing said oxidant (12) with a flow of said gas mixture.

12. Device (1) for reducing pollutants according to any of the preceding claims, wherein the filter unit (10) comprises at least one tubular filter element arranged parallel to the fixed flow direction (D).

Technical Field

The present invention relates to an apparatus for reducing contaminants in a gas mixture.

The development and spread of human activities has over the years led to an increasingly significant increase in the presence of pollutants in the air breathed.

More specifically, there is an increasing concern about the impact of pollutant emissions (e.g., produced by production plants and vehicles) on the environment and on the ecosystem.

However, many studies have demonstrated that the level of contaminants accumulated in the enclosed space can be equal to (or even greater than if not equal to) the level of contaminants present in the external environment.

In general, the most commonly occurring species is Nitrogen Oxide (NO)_x) And include Volatile Organic Compounds (VOCs) which may also be derived from commonly used household items such as cleaning products, deodorants, air conditioning systems and upholstery.

The need to ensure comfort in both indoor and outdoor environments, both at home and at work, without compromising the health of the inhabitants, has led to the study of such devices: the device is capable of removing all those substances that may be harmful to human health, or at least making all those substances harmless.

The need to ensure good air quality is felt more in working environments where activities that produce substances harmful to the operator may take place and where the operator has to stay in the working environment for many hours each day.

Background

Today there are already devices for reducing pollutants, which can be installed inside a closed environment for reducing pollutants below a risk threshold.

There is usually a filter device which is inserted inside a conventional air duct of the working environment.

Prior art devices used as filtering units are generally provided with photocatalytic filters, generally based on the use of photocatalysts, often titanium dioxide, which, in the presence of oxygen and water, are capable of effectively degrading and oxidizing the polluting compounds present in the air mentioned above.

This property makes titanium dioxide a particularly useful compound in the field for manufacturing air filters, since it can significantly improve the quality of the air breathed in the indoor environment and in the working environment.

More specifically, titanium dioxide in the anatase form remains the most promising photocatalytically active semiconductor in this field and much effort has been made to try to optimize the production and application processes of this particular crystalline form.

In more detail, titanium dioxide has photocatalytic properties and can be activated when irradiated with light having a wavelength in the ultraviolet region, for example, between 300nm and 390nm, and therefore activates only 5% of the visible radiation. It follows that this type of device is very inefficient unless it is used in conjunction with an ultraviolet lamp specifically designed and manufactured to perform the function of activating titanium dioxide. This also leads to the fact that: in order to obtain a good level of performance for reducing pollutants by means of filters of the prior art, the device must comprise a series of uv light sources which are characterized by a significant energy consumption and a low durability over time.

It is clear that this energy consumption is significant for the filtering device, which in itself must be continuously operated throughout the working day, and is also problematic for the operating costs of the system in which it is installed.

Another major drawback of uv light sources is the cost of purchase and the relatively low number of life hours, especially if compared to light sources in the visible spectrum of LED types, which are characterized by: very low energy consumption, low purchase cost and at the same time a life cycle that is much larger than that of other conventional light sources.

Disclosure of Invention

In this context, the technical purpose forming the basis of the present invention is to provide a device for reducing pollutants in a gas mixture which overcomes at least some of the several drawbacks of the prior art as described above.

The object of the present invention is to provide a device for reducing pollutants in a gas mixture, which device is characterized by being very effective in removing and reducing pollutants in a gas mixture and at the same time is cheap and reliable in everyday use.

Moreover, the devices for reducing pollutants in a gas mixture with these characteristics are not only designed for treating pollutants in a chamber, but also for treating industrial types of gaseous emissions that need to be treated before being introduced into the atmosphere.

The technical purpose indicated and the aims indicated are substantially achieved by a device for reducing pollutants in a gas mixture comprising the technical features described in one or more of the appended claims.

Drawings

Further characteristics and advantages of the invention will become more apparent in the non-limiting description of a preferred embodiment of the device for reducing pollutants in a gas mixture, illustrated in the attached drawings, wherein:

FIG. 1 shows a schematic cross-sectional view and a non-limiting example of an apparatus for reducing contaminants in a gas mixture according to the present invention;

figure 2 shows a filter unit for use in a device according to the invention;

fig. 3 shows a schematic view of an embodiment of a light source for use in a device according to the invention; and

fig. 4 shows a second embodiment of the device according to the invention.

Detailed Description

Number 1 in fig. 1 indicates in general terms a device 1 for reducing pollutants in a gas mixture, for example air, the device 1 comprising a containment body 2, the containment body 2 having an inlet portion 3 and an outlet portion 4 for the gas mixture.

Advantageously, the containing body 2 can be connected in series with a ventilation duct of a building.

The containing body 2 forms a fixed physical channel imposing a fixed flow direction to the gas mixture, which flow direction is indicated for the sake of simplicity only by the letter "d" in fig. 2.

Advantageously, the containing body 2 comprises an element for resting on the ground.

Inside the containment body there is at least one filtering unit 10, the filtering unit 10 being schematically shown in fig. 1 and 2, the filtering unit 10 comprising a photocatalytic filter 7, the photocatalytic filter 7 being interposed along a fixed flow direction "d" between a first light source 6a and a second light source 6b, the first light source 6a and the second light source 6b each having a wavelength within the visible spectrum.

The light sources 6, 6a, 6b may be of any known type, advantageously of the LED type.

The photocatalytic filter 7 comprises a photocatalytic nanoparticle coating further comprising titanium dioxide doped with a nitrogen dopant.

Preferably, the photocatalytic filter 7 is made of a ceramic material and comprises at least one of cordierite, mullite, alumina.

In addition, preferably, the nitrogen dopant is one of ammonia complex, amide, organic ammonium salt and inorganic ammonium salt.

The filter 7 comprises an application surface and a photocatalytic nanoparticle coating configured for deposition on the application surface.

The nanoparticle coating is prepared by depositing photocatalytically active nanoparticles, preferably anatase titanium dioxide nanoparticles.

The nanoparticle coating is doped with a nitrogen dopant before being applied to the filter.

In other words, the application surface is coated with titanium dioxide in the form of nanoparticles doped with nitrogen.

As mentioned, preferably, the precursor used as nitrogen dopant is selected from among ammine complexes, amides, organic ammonium salts, inorganic ammonium salts.

The coating activation is carried out directly on the surface by heating at a temperature of about 500 ℃.

The presence of nitrogen causes the band gap of the titanium dioxide to be altered, in particular made smaller, so that the photocatalytic properties are activatable over a wide range of the visible spectrum, rather than being activated only with a very limited ultraviolet component (such as that present in prior art devices).

Preferably, the application surface is made of a ceramic material, which is particularly suitable since it provides a very durable and very porous inert support, thus ensuring a long service life of the device in which it is used.

As described above, preferably, at least one of cordierite, mullite, and alumina is used to prepare the application surface.

In order to guarantee optimal filtration results and to maximize the efficiency of the filter 7, the application surface is prepared by a matrix consisting of a plurality of thin ceramic walls defining a plurality of parallel ducts which are open at both ends in such a way as to allow the passage of the gas mixture. In other words, the application surface has a plurality of ducts, each covered with a nanoparticle coating, defining a plurality of oxidation sites where the decontamination of the gas mixture (in particular of the air) passing through the ducts of the application surface is obtained by the absorption and degradation of the pollutants by activating the photocatalytic properties of the titanium dioxide nanoparticles doped with nitrogen dopant using incident photons.

For example, nitrogen oxides undergo degradation to nitrates while other volatile organic species are oxidized to form carbon residues and/or carbon dioxide.

The by-products of the filtration of the air, which are not removed in the air flow, can be easily washed off the application surface, thus completely restoring operation.

Advantageously, the filter unit 10 is of the tube bundle type, that is to say, the filter unit 10 comprises a plurality of hollow tubular elements through the interior of which the gas mixture flow to be treated passes and is arranged parallel to the fixed flow direction "d" described above.

Advantageously, the nanoparticle coating described above extends at least to the inner surface of each of the tubular elements constituting the tube bundle.

Still more advantageously, a respective light source 6, 6a, 6b is arranged inside each tubular element.

In this embodiment, the light sources 6, 6a, 6b are also arranged parallel to the fixed flow direction "d".

Referring to fig. 3, in the device 1 for reducing pollutants in a gas mixture according to the invention, the light sources 6a, 6b may be positioned so that they are not in direct contact with the gas flow of the gas mixture, since the light sources 6a, 6b are inserted inside the respective containers 8.

The container 8 must be at least partially transparent to the visible light emitted by the light sources 6a, 6 b.

Furthermore, advantageously, between the container 8 and the light sources 6, 6a and 6b, there is an air gap 9.

Inside the air gap 9 there is air, the pressure of which is greater than the pressure of the gas mixture flow.

In this way, in case of fire or explosion, additional safety can be obtained.

The application of the device for reducing pollutants in a gaseous mixture with the above characteristics is not limited to the treatment of pollutants in a chamber where the concentration never exceeds the explosive limit, but can also be applied to the treatment of gaseous effluents of the industrial type which require treatment before entering the atmosphere, on the other hand, gaseous effluents of the industrial type which are generally mixtures defined as explosive. The described configuration with air gap 9 allows ATEX classification of the device.

In a preferred embodiment of the device 1 according to the invention, inside the containing body 2, in a position before the filtering units 10, there are means 5 for straightening the air flow, in such a way as to make the air flow more uniform and thus to optimize the operation of all the series of filtering units 10 present in the device 1.

More specifically, the purpose of the device 5 for straightening the air flow is to distribute evenly the flow velocity of the air mass entering from the inlet portion 2 over the working section of the filter unit 10 arranged after the straightening device 5.

The even distribution of the flow velocity of the air mass allows to maximize the contact between said mass and the filtering surface, thus obtaining a greater overall efficiency during the abatement operation.

In order to optimize the operation, and therefore the reduction of contaminants by the filtering unit, the inner surface of the containing body 2 can be made reflective with respect to visible light (or even mirror-like). It is clear that this maximizes the amount of light emitted by the light sources 6, 6a, 6 b.

Furthermore, advantageously, the device 1 according to the invention comprises a recirculation circuit connecting (for example, controlled by a control unit) the outlet portion 4 and the inlet portion 3 of the containment body 2.

The connection between the outlet portion 4 and the inlet portion of the containment body 2 may comprise hollow ducts controlled by opening respective valves.

The valve is in turn controlled by one or more sensors arranged near the outlet portion 4. The sensor is configured to detect the actual percentage of contaminants in the gas mixture after passing through the filter unit 10.

In this way, for example if a sensor located in the outlet portion 4 detects that the percentage of pollutants is greater than a limit value, the flow of gas mixture can be conveyed again through the inlet portion 3 for passing again through the filtering unit 10 instead of through the air duct in the building.

Fig. 4 shows a second solution, according to which the device 1 comprises a containing body 2, the containing body 2 having a first inlet portion 3 for the untreated mixture and an outlet portion 4 for the treated gas mixture. Advantageously, the containment body can be connected in series with a ventilation duct of the building.

The containing body 2 forms a fixed physical channel imposing a fixed flow direction (marked "d") on the gas mixture.

Inside the containment body 2 there is at least one filtering unit 10, the filtering unit 10 being arranged so that the gas mixture passes through the filtering unit 10 along a fixed flow direction "d".

The containing body 2 further comprises a second inlet portion 11 for the oxidizing agent 12, the second inlet portion 11 being arranged before the at least one filtering unit 10. According to the embodiment shown in fig. 4, the second inlet portion 11, designed to introduce the oxidizing agent inside the containment body 2, is located between the first inlet portion 3 for the gas mixture and the filtering unit 10.

According to another alternative embodiment, the second inlet portion 11 for the oxidizing agent 12 is located at the first inlet portion 3, or coincides with the first inlet portion 3.

Advantageously, the oxidizing agent 12 comprises one or more of ozone, hydrogen peroxide or oxygen, hypochlorite and potassium permanganate.

During operation, the oxidizing agent 12 is introduced inside the containing body 2 in a predetermined quantity so as to obtain a good mixing with the gas mixture flow.

Mixing occurs before the gas stream passes through the filter unit 10. The oxidizing agent 12 attacks any odorous molecules contained inside the gas mixture, causing partial or total oxidation and consequent reduction in the overall dimensions.

In short, the oxidant 12 pre-treats the gas mixture before it passes through the filter unit 10.

More specifically, when the oxidizing agent comprises oxygen, ozone, or hydrogen peroxide, or hypochlorite, or potassium permanganate, an oxidation process of chain reaction is obtained, such that when the oxidizing agent comes into contact with the activated titanium present on the photocatalytic filter 7, enhanced free radicals are generated, thus achieving a further reduction in odorous emissions.

Thus, at the outlet from the portion 4, a gas mixture is obtained from which both the odorous molecules and the contaminants have been removed.

The device according to the invention overcomes the limitations of the prior art and achieves the previously set aims.