JP4326403B2 - Dust remover - Google Patents

Description

  The present invention relates to a dust removing device for removing dust, mist and the like contained in a gas.

  In order to efficiently collect fine dust (submicron particles), mist, and the like, the present applicant has proposed a dust removing device according to the prior patent document 1. The dust removing apparatus includes a charging unit that charges a collected substance such as dust or mist contained in a gas, a spray unit that sprays a dielectric material on the collected substance charged by the charging unit, and the spray unit. Electric field forming means for forming an electric field for dielectrically polarizing the dielectric dispersed by the means, and dielectric collecting means for collecting the dielectric that has captured the substance to be collected.

The dust removing device includes a high voltage applying electrode 100 and a ground electrode 200 shown in FIG. 7 as electric field forming means, and a substance to be collected such as dust or mist (in this example, a black circle in the figure) between the electrodes 100 and 200. an exhaust gas containing SO ₃ mists) 300 shown in, dielectric sprayed from the spray means (in this example, circulating water mist) 400.

The substance to be collected 300 is negatively charged in advance by the charging means, for example. On the other hand, the dielectric 400 is dielectrically polarized by a DC electric field formed between the electrodes 100 and 200. For this reason, the substance to be collected 300 is collected by the dielectric 400 by the Coulomb force acting between the dielectrics 400. According to the dust removal apparatus according to this prior application, submicron particles can be efficiently collected despite a compact configuration.
JP-A-10-174899

  In order to further improve the collection efficiency of the substance to be collected 300, it is necessary that the dielectric 400 is sufficiently present up to the upper part (rear part) of the electrodes 100 and 200. In the system in which the electric field is formed in parallel with the liquid crystal, the particle size of the sprayed dielectric 400 is larger than the particles of the collected material 300 to be collected. As a result, the dielectric 400 tends to be diluted at the upper part (rear part) of the electrodes 100 and 200. The present inventors have found that the above-mentioned tendency is caused by the charging of the dielectric material sprayed from the spray means. In other words, the dielectric material sprayed from the spray means exchanges charges at the boundary with the conduit through which it flows, and thus is charged positively or negatively. Therefore, the positively or negatively charged dielectric 400 is scattered from the spray means, which causes the above-described tendency as described below.

In FIG. 8 corresponding to FIG. 7, a circle mark attached to one part of the dielectric 400 (water mist in this figure) indicates a charged state of the dielectric 400. When the charged dielectric 400 is supplied between the electrodes 100 and 200, the positively charged dielectric 400 is attracted to the electrode 100 side, and the negatively charged dielectric 400 is attracted to the electrode 200 side by Coulomb force. It is done. Therefore, most of the dielectric 400 is collected by the electrodes 100 and 200 before reaching the upper part (rear part) of the electrodes 100 and 200. In this case, the trapped substance 300 is SO ₃ mist having a very small particle diameter.

  The subject of this invention is providing the dust removal apparatus which prevented the dilution of the dielectric material in the back part of an electric field formation means based on such a situation, and improved the collection efficiency.

As a result of diligent investigations to solve the above problems, the present inventors have, as a means for preventing the dilution of the dielectric behind, to hold the dielectric in the space without collecting the dielectric and to reduce the electric field. As a forming means, the inventors have conceived a configuration in which the area of the electrode for collecting the dielectric is minimized or the electrode is eliminated.
In other words, in order to achieve the above object, the present invention provides a dust removing device comprising a charging means for charging a collected substance such as dust and mist contained in a gas, and a charged object charged by the charging means. It consists of spraying means for spraying a dielectric material on the trapping material and a mesh-like material with a large aperture ratio that is perpendicular to the gas flow direction and does not impede the gas flow. It consists of a mesh electrode material with a large aperture ratio that does not impede gas flow, and a high-voltage applied electrode that does not have a thickness substantially in the gas flow direction. An electric field forming means for forming a DC electric field in the gas flow direction and dielectrically polarizing the dielectric by the DC electric field; and a dielectric collecting means for collecting the dielectric that has captured the substance to be collected. With this The features.

  In another form, the dust removing apparatus according to the present invention is a charging means for charging a collected substance such as dust or mist contained in a gas, and a dielectric material is added to the collected substance charged by the charging means. Spray means for spraying, wherein a dielectric is sprayed from charged nozzles having different polarities, and a self-electric field is formed in parallel along the gas flow direction by the charged dielectric group sprayed from the charged nozzle. A spray means and a dielectric collecting means for collecting a dielectric that has captured the substance to be collected are provided.

The dust removing apparatus according to the present invention is still another embodiment, and includes a charging means for charging the collected substance such as dust and mist contained in the gas, and a collected substance charged by the charging means. Spraying means for spraying a dielectric material from a charging nozzle to which an alternating voltage is applied, sprayed from the charging nozzle, and charged in a flow direction of the gas by a dielectric group charged with positive and negative fluctuations over time. It is characterized by comprising spray means for forming a self electric field and dielectric collecting means for collecting a dielectric that has captured the substance to be collected.
In the dust removing apparatus according to the present invention, in each of the above-described embodiments, as the spray means for spraying the dielectric material on the charged trapped substance, a liquid is used as the dielectric material, and a two-fluid nozzle is used as the spray nozzle. be able to. As the liquid used as the dielectric, it is generally preferable to use water, particularly fresh water.

  ADVANTAGE OF THE INVENTION According to this invention, the dust removal apparatus which prevented the dilution of the dielectric material in the back part of an electric field formation means, and was able to improve collection efficiency is provided.

  Embodiments of a dust removing apparatus according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic longitudinal sectional view showing the overall configuration of a dust removing apparatus to which the present invention is applied. The dust removing device includes a preliminary charging unit 1, a spray unit 2, and a dust collecting unit 3. As shown in FIG. 2, the preliminary charging unit 1 includes a plurality of ground electrodes 4 (positive electrodes) arranged in parallel and a discharge electrode (negative electrode) 5 disposed between the ground electrodes 4. . The discharge electrode 5 includes a plurality of (three in this example) conductive rods 5a arranged vertically in a plane parallel to the ground electrode 4, and a number of barbs along the vertical direction of these rods 5a. 5b is arranged at appropriate intervals.
The above configuration is the same as that of a conventional dust collector, but is not limited to the structure shown in FIG. 1 because the main purpose is to charge and collect the substance to be collected.

  As shown in FIG. 3, the spray unit 2 has a large number of dielectric spray nozzles 6 arranged below the dust collection unit 3. Each nozzle 6 is formed at a suitable interval in a plurality of tubes 7 arranged horizontally. As shown in FIG. 1, since the pipe 7 is connected to the dielectric storage tank 8 through the pipe 13, the dielectric (in this example) in the storage tank 8 is pumped by the pump P interposed in the pipe 13. When water 10 is pumped up, the mist-like dielectric 10 is sprayed from the nozzle 6.

  In the dust removal apparatus having the above-described configuration, as shown by an arrow in FIG. 1, exhaust gas to be dust-removed (for example, exhaust gas generated when coal, heavy oil, or the like is burned) is introduced into the preliminary charging unit 1. The exhaust gas passes between the ground electrode 4 and the discharge electrode 5 shown in FIG. 2, and at this time, the collected substances such as dust and mist contained in the exhaust gas are the electrodes 4, 5. Charge is given by corona discharge generated between the two. In this example, the substance to be collected is negatively charged by applying the charge.

The exhaust gas that has passed through the preliminary charging unit 1 flows into the gas absorption zone 15 shown in FIG. 1, then flows upward, and is introduced into the dust collecting unit 3 together with the dielectric 10 dispersed from the spray unit 2. . The dispersed dielectric 10 collects the substance to be collected by the dust collection unit 3.
In the present embodiment, the dielectric 10 is circulated water to be circulated, and the circulated water also has a function of absorbing exhaust gas.
In the present invention, the spray unit 2 and the dust collection unit 3 have a characteristic configuration, and the embodiment shown in FIGS. 4 to 6 to be described later will be described in further detail together with a mechanism for collecting a substance to be collected.
The dielectric 10 to which the substance to be collected adheres is collected by a dielectric collecting unit 16 constituted by a demister or the like. Therefore, a clean gas from which the substance to be collected is removed is discharged from the dielectric collecting unit 16. In addition, the dielectric material collection part 16 comprised with the demister etc. may comprise some earth electrodes mentioned later.

  By the way, since this dust removal apparatus is applied to processing of harmful gas in the embodiment of FIG. 1, the dispersed dielectric 10 absorbs part of the harmful gas. That is, for example, when the dust-containing gas contains a harmful gas such as SOx, the dielectric 10 absorbs the SOx and the like while the dielectric 10 is circulated. As described above, when the dielectric 10 absorbs the harmful gas, the PH value of the dielectric 10 is lowered, which causes problems such as corrosion. Therefore, in the present dust removing apparatus, a fresh water supply pipe 51 with a valve 50 interposed therein, a drain pipe 53 with a valve 52 interposed therein, an absorbent supply pipe 55 with a valve 54 interposed therebetween, and the valves 50 and 52 described above. And a controller 56 for controlling 54 and 54 are provided to solve the above problem.

  That is, the dielectric 10 in the storage tank 8 contains a reaction product according to the amount of absorption (processing amount) of SOx or the like contained in the dust-containing gas. Therefore, the controller 56 controls the valves 50 and 52 based on the output of the concentration sensor 57 that detects the concentration of the reaction product in the liquid so that the concentration in the liquid shows a certain range of values. That is, the amount of fresh water injected into the tank 8 and the discharge amount of the dielectric 10 from the tank 8 are adjusted. Further, the controller 56 controls the valve 54 based on the output of the PH sensor 58 that detects the PH concentration of the dielectric 10 in the tank 8 so that the PH concentration shows a value within a certain range. That is, the amount of the absorbent (for example, NaOH, Mg, etc.) that absorbs the reaction product to the tank 8 is adjusted. By controlling the concentration of the reaction product in the liquid and the pH of the dielectric 10 as described above, not only can the corrosion be prevented, but the harmful gas can be actively removed by utilizing the harmful gas absorption action of the dielectric 10. Can be removed. In the above, the concentration of the reaction product in the liquid is managed based on the output of the concentration sensor 57. However, the concentration management can be performed without using the concentration sensor 57. That is, since the average increase degree of the concentration in the liquid is known in advance by experiments or the like, the amount of new dielectric material (fresh water) injected into the tank 8 corresponding to the increase degree and the amount of dielectric material from the tank 8 If the discharge amount is determined in advance and the valves 50 and 52 are controlled so that the injection amount and the discharge amount are realized, the concentration of the reaction product in the liquid can be set within a certain range.

  Next, the specific configuration of the spray unit 2 and the dust collection unit 3 and the configuration and mechanism for collecting the substance to be collected will be described in more detail with respect to the embodiment shown in FIGS.

First, FIG. 4A shows a first embodiment of the specific configuration of the spray unit 2 and the dust collecting unit 3.
The embodiment of FIG. 4A includes an electric field forming means 60 in the dust collecting unit 3 of FIG. The electric field forming means 60 has a mesh-shaped ground electrode 61 (positive electrode) having a large aperture ratio that does not hinder the flow of two exhaust gases arranged in parallel, and the flow of the exhaust gas disposed between the ground electrodes 61. A mesh-like high voltage application electrode 62 (which is a negative electrode in this figure, but not limited) having a large aperture ratio that is not obstructed is provided so as to be orthogonal to the flow direction of the exhaust gas. A voltage is applied to the high voltage application electrode 62 by the high voltage generator 63.
The space in the gas flow direction between the electrodes 61 and 62 adjacent to each other is set so as to have a spacing of 60 cm with a voltage difference of 60 kv at 1 kv / cm, for example. In this figure, one high voltage application electrode 62 is arranged in the gas flow direction, but a plurality of high voltage application electrodes and a plurality of ground electrodes are arranged adjacent to each other in the gas flow direction to apply an electric field. It is possible to improve the performance by securing the region to be retained and the gas staying in the electric field for a longer time.

  Each of the electrodes 61 and 62 is made of a mesh-shaped material having a large aperture ratio that is orthogonal to the gas flow direction and does not inhibit the gas flow. Here, the mesh-like material may be any material that can permeate the exhaust gas, and any of a grid-like shape, a net-like shape, and a porous shape may be adopted as long as the object of the present invention is not violated. Can do. In addition, it is desirable that the material itself is basically conductive by itself, but it is not necessarily limited to conductivity as long as an electric field can be efficiently formed. In particular, even if a metal conductive material is coated with a highly corrosive and highly insulating material such as ceramic or lining material, a uniform electric field can be obtained by applying a high voltage to the internal conductive material part or connecting it to ground. Can be formed, and stable operation is possible even in a corrosive atmosphere where toxic substances are handled. And since the material does not obstruct the gas flow and by itself has little (substantially) thickness in the direction of gas flow, the dielectric is almost (substantially) collected by these electrodes. Since the electrode portion passes through the electrode portion instantaneously without being reduced, the amount of the dielectric is hardly (substantially) decreased even in the rear, and the trapped substance can be taken in efficiently.

In the embodiment of FIG. 4A, when a voltage is applied to the electrode 62 by the high voltage generator 63, an electric field is formed in the gas flow direction. Here, when the mist-like dielectric 10 is ejected from the nozzle 6 upward in the drawing, that is, in the gas flow direction, the water mist 64 is generated by the formed electric field as shown in FIG. Is positively or negatively polarized.
The dielectric 10 is a liquid. In general, when the water is not circulated, fresh water is particularly preferable. The same applies to the second and third embodiments. The nozzle 6 is a spray nozzle, and is preferably a fluid nozzle. Further, a nozzle capable of supplying a large number of mist particles with a small amount of spraying, that is, a two-fluid nozzle or a pressurizing nozzle. A single fluid nozzle is preferred. This is the same in the second and third embodiments.
Particles 65 to be collected such as dust and mist that have been negatively precharged by the precharging device 1 are attracted to the positive side of the water mist 64 and captured. And the water mist 64 which captured the to-be-collected substance is collect | recovered by the dielectric material collection part 16 (FIG. 1) comprised with the demister etc.

  In the first embodiment, since an electric field is formed in the gas flow direction, the problem that the dielectric is collected at the lower part (front part) of the left and right electrodes as in the prior art is eliminated. Therefore, the dielectric 10 diffuses to the upper part (rear part) of the dust collection part 3, and the substance to be collected can be efficiently captured.

Next, FIGS. 5A and 5B show a second embodiment of the specific configuration of the spray unit 2 and the dust collecting unit 3.
In this embodiment, the nozzle 6 on the tube 7 is configured as a set of charging nozzles 6a and 6b provided in the tube width direction.
These charging nozzles 6a and 6b are configured to be able to charge the ejected dielectric so that the dielectric 10 ejected by 6a is positive and the dielectric 10 'ejected by 6b is negative. As a result, the injected dielectric itself is charged with the positive and negative charges of the sprayed dielectric group in FIG. 5B and exists in the gas. An electric field is formed between these groups in a direction perpendicular to the gas flow.

As the configuration of the charging nozzles 6a and 6b themselves, those known to those skilled in the art can be adopted. For example, it is possible to give a charge to the dielectric using a technique such as induction charging or corona discharge.
Further, the charging nozzles 6a and 6b are not based on a method of applying an electric charge to the dielectric from the outside, but use a principle that can be charged by flowing using a filter-like material in the flow path of the nozzle, for example, organic An equivalent function can also be achieved by disposing a nozzle having a material filter inserted (positively charged in flow) and a nozzle having an inorganic filter inserted (negatively charged in flow) as shown in FIG.
The charging nozzles 6 a and 6 b are provided with positive and negative nozzles in the width direction of the tube 7, but it is also possible to form an electric field by arranging positive and negative nozzles adjacent to each other in the longitudinal direction of the tube 7.

In this second embodiment, negatively precharged particles 65 of the trapped substance are positively charged dielectric 10 (water mist group) and negatively charged dielectric 10 '(water mist group). It is guided into the formed electric field and is effectively trapped in the dielectric 10 by electrostatic force. Since the dielectric itself forms an electric field without using an external electrode, the amount of the dielectric in the gas is partially enlarged even though it is behind, but the decrease in the number is kept small. Therefore, it becomes possible to take in the substance to be collected efficiently.
After that, as in the first embodiment, the dielectric 10 (water mist group) that has captured the substance to be collected is collected by the dielectric collection unit 16 (FIG. 1) configured by a demister or the like.

  In this second embodiment, an electric field is formed perpendicular to the gas flow direction, but the conventional problem that the dielectric is collected at the lower (front) portion of the left and right electrodes is eliminated. The This is because the dielectric itself constitutes the electrode. Therefore, the dielectric material diffuses up to the upper part (rear part) of the dust collection part 3, and the substance to be collected can be efficiently captured.

Next, FIGS. 6A and 6B show a third embodiment of the specific configuration of the spray unit 2 and the dust collecting unit 3.
In this embodiment, AC is supplied to the charging nozzles 6a and 6b of the second embodiment, and an alternating electric field is applied to the charging nozzles 6a and 6b. Other components are the same as those in the embodiment of FIG.
In this embodiment, the polarity of the charge held by the dielectric 10 (10 ′) varies with time. Therefore, an electric field is formed in the gas flow direction by alternately forming dielectric groups (water mist groups 66, 67, 68,...) Having positive and negative charges in the upper and lower gas flow directions. It becomes possible to do. In addition, in this Embodiment, although formed in the up-down gas flow direction, if it is a gas flow direction, it will not be limited to up-down.
Also in the third embodiment, the negatively precharged particles 65 of the trapped substance are guided into the electric field formed by the dielectrics 10 and 10 ', and the dielectric 10 is effectively effective by electrostatic force. 10 '. After that, as in the first and second embodiments, the dielectrics 10 and 10 '(water mist group) that have captured the substance to be collected are the dielectric collecting part 16 (Fig. Collected in 1).

  In the third embodiment, as in the second embodiment, an electric field is formed by the dielectric itself. However, unlike the second embodiment, an electric field is formed in the gas flow direction. The conventional problem that the dielectric is collected at the lower part (front part) of the left and right electrodes can be solved more effectively. Therefore, the dielectric material diffuses up to the upper part (rear part) of the dust collection part 3, and the substance to be collected can be efficiently captured.

  The dust removing apparatus according to the present invention comprises the spray part 2 and the dust collecting part 3 as described in the first to third embodiments, thereby diluting the dielectric in the rear part of the electric field forming means. It is possible to prevent and improve the collection efficiency.

It is the schematic longitudinal cross-sectional view which showed the whole structure of the dust removal apparatus which concerns on this invention. It is the schematic perspective view which showed the structure of the preliminary charging part. It is the schematic perspective view which showed the structure of the spray part. It is a conceptual diagram explaining 1st Embodiment which comprises an electric field with dielectric material itself with the dust removal apparatus of this invention. (A) is a side view, (b) is the A section enlarged view. It is a conceptual diagram explaining 2nd Embodiment which comprises an electric field with dielectric material itself with the dust removal apparatus of this invention. (A) is a side view, (b) is a front view. It is a conceptual diagram explaining 3rd Embodiment which comprises an electric field with dielectric material itself with the dust removal apparatus of this invention. (A) is a side view, (b) is a front view. It is explanatory drawing which shows the principle of general dust collection in a direct current electric field. It is explanatory drawing which illustrated the behavior of the dielectric material in the direct current electric field in the conventional dust removal apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Precharge part 2 Spray part 3 Dust collection part 4 Discharge electrode 6 Nozzle 9 Collected substance 10 Dielectric 50, 52, 54 Valve 56 Controller 57 Concentration detection sensor 58 PH detection sensor 61, 62 Electrode 63 High voltage generator 64 Water mist 65 Substance to be collected

Claims (5)

A charging means for charging the collected substances such as dust and mist contained in the gas, a spray means for spraying a dielectric material on the collected substances charged by the charging means, and a direction orthogonal to the gas flow direction It is composed of a mesh material with a large opening ratio that does not hinder gas flow , and by itself, a ground electrode that does not have a substantial thickness in the gas flow direction and a mesh material with a large opening ratio that does not hinder gas flow A high voltage application electrode that is not substantially thick in the gas flow direction alone is arranged in the gas flow direction in parallel with each other to form a DC electric field in the gas flow direction, and the dielectric material is generated by the DC electric field. A dust removing apparatus comprising: an electric field forming means for dielectrically polarizing a body; and a dielectric collecting means for collecting a dielectric that has captured the substance to be collected.   The charging means for charging the collected substances such as dust and mist contained in the gas, and the spray means for spraying the dielectric material to the collected substances charged by the charging means, which are different from each other A spray means for spraying a dielectric from a charging nozzle, and forming a self electric field in parallel along the gas flow direction by the charged dielectric group sprayed from the charging nozzle, and a dielectric for capturing the collected substance A dust removing device comprising a dielectric collecting means for collecting a body.   A charging means for charging a substance to be collected such as dust or mist contained in gas, and a spray means for spraying a dielectric material on the substance to be collected charged by the charging means, wherein an alternating voltage is applied. Spray means for spraying a dielectric from a charging nozzle, spraying from the charging nozzle, and forming a self electric field in the gas flow direction by a dielectric group charged with positive and negative fluctuations with time, and the trapped substance A dust removing device comprising: a dielectric collecting means for collecting a dielectric that has captured the material.   The spraying means for spraying a dielectric on a charged substance to be collected uses a liquid as a dielectric and a two-fluid nozzle as a spray nozzle. Dust removal equipment.   The dust removing apparatus according to claim 4, wherein fresh water is used as the liquid used as the dielectric.

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