System for air pollution control

Abstract

The invention relates to a system (1) for pollution control of the air in a zone (90). This pollution control system (10) comprises a first filtration stage (10) which comprises at least one filtering element (11), which is an electrostatic filter able to ionise the polluting particles (91) present in the air of the zone (90), this system (1) comprises a second collection stage (20) able to collect these ionised particles (91), the second stage (20) being located downstream of and separated from the first stage (10) in the direction (X) of flow of the air through the system (1), and this system (1) comprises an air movement device (80) which is intended to move and direct the air polluted with the polluting particles (91) towards the stages (10, 20).

Description

Description Title: Air pollution control system

[0001] The present invention relates to an air pollution control system for an area with the aim of removing polluting particles and possibly polluting gases.

[0002] In certain locations, emissions of fine particulate matter lead to significant airborne concentrations in open and semi-open areas where people are exposed. Examples of such areas include highway interchanges, tunnels, airports, industrial zones, construction sites, and urban areas. Furthermore, certain events, such as forest fires or fires in buildings or industrial sites, can generate polluting particles in a given area. The increasing volume of human activity makes this air pollution problem ever more critical, as this pollution is harmful to health.

[0003] Currently, filtration systems exist for enclosed spaces such as buildings, these systems generally being coupled with a heating and air conditioning system. There are also systems for semi-open areas, that is, partially enclosed spaces with permanent openings to the outside. All these systems operate with low air circulation velocities to limit the power required for this circulation. For some filtration technologies, a low circulation velocity is also necessary to allow for a sufficiently long air treatment time. Consequently, these systems can only treat low airflow rates. They are therefore better suited to enclosed spaces (buildings). Using these systems for semi-open areas requires treating higher flow rates, which is only possible if these systems have a large cross-sectional area, and therefore a large footprint.There are no viable and reliable systems for the remediation of open areas. Description of the invention

[0004] The present invention aims to remedy these drawbacks.

[0005] The invention aims to provide a pollution control system that is compact, has the lowest possible power consumption, is as quiet as possible, and is capable of effectively depolluting an open or semi-open area in order to reduce the concentration of fine particles present in that area.

[0006] This goal is achieved through the fact that the pollution control system includes a first filtration stage which has at least one filter element, the at least one filter element being an electrostatic filter capable of ionizing the polluting particles present in the air of the area, through the fact that it includes a second collection stage capable of collecting these ionized particles, the second stage being located downstream and separated from the first stage along the X direction of airflow through the system, and through the fact that it includes an air displacement device which is intended to move and direct the polluted air with the polluting particles towards these stages.

[0007] Thanks to these features, the air purification system is capable of handling a high volume of air in a compact unit while minimizing power consumption. Furthermore, unlike existing solutions based on HEPA filters that become clogged over time, this system maintains its energy efficiency throughout its operation. In addition, the system requires no consumables, as the filters do not need to be replaced. A simple washing of the electrostatic filters removes fine particles, rendering them clean and ready for use in the system. Moreover, the air displacement device accelerates the air immediately upstream of the first floor, increasing the airflow through the floors and thus enhancing the effectiveness of the purification process.

[0008] For example, at least one filter element includes at least one smooth plate parallel to the X direction of airflow.

[0009] For example, the first stage of filtration also includes a gas filter.

[0010] For example, the pollution control system further includes a third diffusion stage which is located downstream of the second stage and which is capable of dividing and diverting the air flowing through the system.

[0011] For example, the third diffusion stage includes a plurality of air guide plates that flow through the system.

[0012] For example, the pollution control system is transportable and orientable.

[0013] For example, the pollution control system includes a container that holds the stages and the air displacement device.

[0014] For example, the length of the system is less than or equal to 1200 cm and the transverse dimensions of the system are less than or equal to 250 cm.

[0015] For example, the air displacement device has an efficiency of over 80%.

[0016] The invention also relates to a method for cleaning the air of an area.

[0017] According to the invention, the process comprises the following steps: (a) A first stage of filtration is provided which includes at least one filter element which is an electrostatic filter capable of ionizing polluting particles present in the air of the area; (b) A second collection stage is provided, capable of collecting these ionized particles, the second stage being located downstream and separated from the first stage along the X direction of airflow through the stages; (c) An air displacement device is provided which is capable of moving and directing polluted air with polluting particles to the floors.

[0018] According to the invention, the method further comprises the following step: (d) A third diffusion stage is provided which is located downstream of the second stage and which is capable of dividing and diverting the air flowing through the third stage in the X direction of airflow.

[0019] According to the invention, the method further comprises the following step: (e) A container is provided in which the stages and the air displacement device are placed to enable their transport.

[0020] The invention will be better understood and its advantages will become more apparent upon reading the following detailed description of embodiments shown by way of non-limiting examples. The description refers to the accompanying drawings in which:

[0021] [Fig. 1] Figure 1 is a perspective view of a pollution control system according to the invention.

[0022] [Fig. 2] Figure 2 is a perspective view of a first filtration stage of the pollution control system of Figure 1.

[0023] [Fig. 3] Figure 3 is a perspective view of another embodiment of a pollution control system according to the invention.

[0024] [Fig. 4] Figure 4 is a perspective view of a third filtration stage of the pollution control system of Figure 3.

[0025] [Fig. 5] Figure 5 is a perspective view of an alternative embodiment of a pollution control system according to the invention Detailed description of the invention

[0026] In the description below, the terms "upstream" and "downstream" are defined with respect to the normal direction of airflow in the pollution control system 1, at least as it enters this system. The airflow direction is a longitudinal direction X, and the direction of air circulation is indicated by a solid arrow in the figures.

[0027] Figure 1 represents an air pollution control system 1 for a zone 90. This zone is open, semi-open, or closed (such as a building). An open or semi-open zone is, for example, a road interchange, a tunnel, an airport, an industrial area, a construction site, an urban area, a machine testing area (for example, an aeronautical turbomachine), or an area polluted by a weather event (forest fire). Zone 90 contains polluting particles 91, and possibly polluting gases.

[0028] The pollution control system 1 includes a first filtration stage 10 which comprises one or more filter elements 11. Each filter element 11 is an electrostatic filter which is capable of ionizing the polluting particles 91 present in the air of zone 90. Each filter element 11 comprises at least one smooth plate 115 capable of ionizing polluting particles 91 and which is parallel to the direction X of airflow. This plate or these plates 115 are electrically conductive, for example, metallic, so that an electric field can be applied to them to achieve this ionization of the polluting particles 91. In Figure 2, which represents a first filtration stage 10, only one filter element 11 is present, and contains several parallel plates 115. This alignment of the plates 115 with each other and with respect to the direction X of flow makes it possible to limit pressure losses through the first filtration stage 10 and to obtain substantially constant pressure losses over the operating time.This is an advantage compared to other filters that require air to pass through a porous medium (such as HEPA filters), which generates significant pressure drops that increase over time due to the clogging of pores by polluting particles. These pressure drops lead to a reduction in the energy efficiency of these filters.

[0029] Alternatively, the first filtration stage 10 also includes a gas filter 12. This gas filter 12 is capable of capturing the polluting gas(s) present in zone 90 and is located upstream or downstream of the filter elements 11, as shown in Figure 2. For example, these polluting gases are carbon dioxide (CO2), SOx, and NOx. Depending on the requirements, the first stage 10 can be configured with more or fewer filter elements 11 and / or gas filters 12 according to the pollution control needs. The pollution control system 1 is therefore modular.

[0030] The pollution control system 1 includes a second collection stage 20 which is capable of collecting the particles 91 after their ionization in the first filtration stage 10. The second stage 20 is located downstream and is separated from the first stage 10 along the flow direction X. Thus, the collection function (by the second stage 20) of the pollution control system 1 is separated from the ionization function (of the first stage 10), unlike existing electrostatic filters where these two functions are implemented in a single cell. This separation is achieved by positioning the second collection stage 20 at a non-zero distance downstream of the first filtration stage 10. In this way, the polluting particles 91 have time to ionize before reaching the The second collection stage 20, even when the airflow velocity through the pollution control system 1 is higher, ensures filtration of over 80% of polluting particles 91 for all particle sizes, particularly finer particles. For example, the second collection stage 20 comprises a plurality of plates parallel to the flow direction X, with alternating positively and negatively charged plates to capture ionized polluting particles 91. This plate arrangement minimizes pressure losses across the second collection stage 20.

[0031] The pollution control system 1 includes an air displacement device 80 designed to move and direct the polluted air containing particles 91 towards the stages (10, 20) of the pollution control system 1. This device 80 also accelerates the air upstream of the stages (10, 20). The air displacement device 80 is located upstream of the stages (10, 20), in which case it can also compress the air. This situation is illustrated in Figure 1. In an alternative embodiment, the air displacement device 80 is located downstream of the stages (10, 20), in which case it draws air from upstream of the first filtration stage 10 through the stages (10, 20). This situation is illustrated in Figure 5, which is identical to Figure 3 except for the placement of the air displacement device 80. For example, this device 80 is a fan or a compressor.Advantageously, device 80 exhibits an efficiency greater than 80%, for example, greater than 85%, or even greater than 90%. Efficiency is the ratio between the compression energy transferred to the air and the energy input into the compressor / fan. To achieve these high efficiencies, one or more parameters of device 80, such as blade geometry, blade area, and clearances between components, are optimized.

[0032] Thanks to the air displacement device 80, the pollution control system 1 is capable of treating air passing through it at higher flow velocities, making the pollution control system 1 more efficient and energy-saving (total electrical consumption will be lower, for example, less than 300 kW, for example, less than 200 kW). Advantageously, the air displacement device 80 is sized for to produce upstream of the first stage 10 a sufficient overpressure to overcome all pressure losses across the stages (10, 20) while maximizing the airflow. Advantageously, the power of the air displacement device 80 is optimized to adapt to the clogging of the collection stage 20 with the operating time of the pollution control system 1.

[0033] Furthermore, pollution control system 1 is more compact in a transverse plane (perpendicular to the X direction of flow). Indeed, due to the law of conservation of mass, for the air to pass through pollution control system 1 at lower speeds than its speed before entering the system, the cross-sectional area of ​​the pollution control device 1 would need to be increased, and therefore the size of this system would need to be increased.

[0034] Thus, the pollution control system 1 according to the invention is capable of efficiently treating air flow rates exceeding 100,000 m³ / s 3 / h, or even exceeding 450,000 m 3 / h through a section less than 5 m 2

[0035] In another embodiment, which is illustrated in The pollution control system 1 further includes a third diffusion stage 30 located downstream of the second stage 20. This third diffusion stage 30 is capable of dividing and diverting (from the longitudinal direction X) the air flowing through the pollution control system 1. Thus, the third diffusion stage 30 allows the treated airflow to be diverged and slowed down so that it remains as much as possible within the area 90 that is to be treated. For example, as illustrated in Figure 4, this third diffusion stage 30 comprises a plurality of guide plates (31, 32) that are oriented obliquely at different angles to each other with respect to the longitudinal direction X. For example, these plates form diverging corners in the direction of the airflow. The air displacement device 80 is located upstream of the floors (10, 20, 30), in which case it propels air through these floors (10, 20, 30).In one embodiment, the air displacement device 80 is located downstream of the stages (10, 20, 30), in which case it draws air from upstream of the first filtration stage 10 through the stages (10, 20, 30). In another embodiment, the air displacement device 80 is located downstream of the first filtration stage 10 and the second collection stage 20 and upstream of the third stage 30.

[0036] Advantageously, the pollution control system 1 is transportable from one location to another and can be oriented in space. This allows the pollution control system to be moved to a polluted site at will. Furthermore, the pollution control system 1 can be oriented so that the wind directs the pollution towards it, thereby reducing the power required by the air displacement device 80 upstream of the pollution control system 1. The energy needed to operate this system is thus minimized. The pollution control system 1 can also be positioned vertically or horizontally as needed.

[0037] To facilitate the transport of the pollution control system 1, this system includes a container 70 which houses the stages (10, 20, 30) and the air displacement device 80. The term "container" refers to any receptacle. For example, this container 70 is a shipping container whose length (along the flow direction X) is less than or equal to 1200 cm and whose transverse dimensions are less than or equal to 250 cm. The container 70 is illustrated in Figures 1, 3, and 5.

[0038] Advantageously, the 70 container is equipped with a handling interface which can be removably attached to a handling device in order to transport and orient this 70 container. For example, this transport is carried out by truck or by train.

[0039] Advantageously, container 70 has doors at its upstream and downstream ends. These doors can be opened to allow for the direct and rapid on-site use of the pollution control system 1 and can be closed during transport of the pollution control system 1.

[0040] The use of container 70 also allows several pollution control systems 1 to be positioned in series or in parallel on a site according to pollution control needs.

[0041] Advantageously, the pollution control system 1 further includes one or more outdoor air analyzers 40 and a control unit 50, which can be housed in the container 70. For example, an analyzer 40 measures the particle density 91 and / or the concentration of polluting gases. The control unit 50 is connected to the air analyzers 40, the floors (10, 20, 30), and the device 80. Air displacement is used to control the operation of these stages (10, 20, 30) and this device 80. These connections are illustrated with thick lines in Figures 1, 3, and 5. For example, the control unit 50 can stop the air displacement device 80 if the analyzers 40 measure that the outside air is becoming less polluted. For example, the control unit 50 can slow down the air displacement device 80 at night to reduce noise.

[0042] The invention also relates to a method for purifying the air in an area as described above. This method comprises the following steps: (a) A first filtration stage 10 is provided which includes at least one filter element 11 which is an electrostatic filter capable of ionizing polluting particles 91 present in the air of zone 90; (b) A second collection stage 20 is provided suitable for collecting said particles 91, the second stage 20 being located downstream and separated from the first stage 10 along the direction X of air flow through the stages (10, 20); (c) An air displacement device 80 is provided which is capable of moving and directing the polluted air with the polluting particles 91 to the floors (10, 20). (d) Optionally, a third diffusion stage 30 is provided which is located downstream of the second stage 20 and which is capable of dividing and diverting the air flowing through the third stage 30 along the X direction of airflow; (e) Optionally, a container 70 is provided in which the stages (10, 20, 30) and the air displacement device 80 are placed to allow their transport. The stages (10, 20, 30) are removable.

[0043] According to one operating mode of the air pollution control process, the following steps are also carried out: - The pollution control system, which includes these stages, is positioned in one location. - The system is anchored to the ground to prevent it from moving. - The stages (10, 20, 30) and the air displacement device 80 and analyzers 40 are connected to a control unit 50 and the content of polluting particles and polluting gases in the air is measured. - We start the pollution control system. - We stop the pollution control system and perform the reverse operations of previous steps, and we clean the filters (11, 12).

Claims

Demands

1. Air purification system (1) for an area (90), said air purification system (10) being characterized in that it comprises a first filtration stage (10) which includes at least one filter element (11), said at least one filter element (11) being an electrostatic filter capable of ionizing the polluting particles (91) present in the air of said area (90), in that it comprises a second collection stage (20) capable of collecting said ionized particles (91), said second stage (20) being located downstream of and separated from said first stage (10) along the direction (X) of airflow through said system (1), and in that it comprises an air displacement device (80) which is intended to move and direct the polluted air with said polluting particles (91) towards said stages (10, 20).

2. Pollution control system (1) according to claim 1 such that said at least one filter element (11) comprises at least one smooth plate (115) parallel to said direction (X) of air flow.

3. Pollution control system (1) according to claim 1 or 2 wherein said first filtration stage (10) further comprises a gas filter (12).

4. A pollution control system (1) according to any one of claims 1 to 3 further comprising a third diffusion stage (30) which is located downstream of said second stage (20) and which is capable of dividing and diverting the air flowing through said system (1).

5. Pollution control system (1) according to claim 4, wherein said third diffusion stage (30) comprises a plurality of air-guiding plates (31, 32) flowing through said system (1).

6. Pollution control system (1) according to any one of claims 1 to 5 such that it is transportable and steerable.

7. A pollution control system (1) according to claim 6, comprising a container (70) which contains said stages (10, 20, 30) and said air displacement device (80).

8. A pollution control system (1) according to any one of claims 1 to 7, wherein the length of said system (1) is less than or equal to 1200 cm and the cross-sectional dimensions of said system (1) are less than or equal to 250 cm.

9. Pollution control system (1) according to any one of claims 1 to 8 wherein said air displacement device (80) has an efficiency greater than 80%.

10. A method for depolluting the air of an area characterized in that it comprises the following steps: (a) A first filtration stage (10) is provided which includes at least one filter element (11) which is an electrostatic filter capable of ionizing polluting particles (91) present in the air of said zone (90); (b) A second collection stage (20) is provided, suitable for collecting said ionized particles (91), said second stage (20) being located downstream and separated from said first stage (10) along the direction (X) of air flow through said stages (10, 20); (c) An air displacement device (80) is provided which is capable of displacing and directing the polluted air with said polluting particles (91) towards said floors (10, 20).

11. A pollution control process according to claim 10, further comprising the following step: (d) A third diffusion stage (30) is provided which is located downstream of said second stage (20) and which is capable of dividing and diverting the air flowing through said third stage (30) in said direction (X) of air flow.

12. A pollution control method according to claim 10 or 11, comprising the following step: (e) A container (70) is provided in which said stages (10, 20, 30) and said air displacement device (80) are placed in order to permit their transport.

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