JPH02184357A - Dust collector - Google Patents

Abstract

PURPOSE:To collect granular substance by providing a discharge electrode in the gas flow contg. granular substance and providing a filter having a counter electrode oppositely to the discharge electrode and impressing high voltage between the discharge electrode and the filter and providing the closed space in the filter. CONSTITUTION:Discharge electrodes 6 are provided in the gas flow contg. granular substance and also the filters 8 having the counter electrodes are provided oppositely to the discharge electrodes 6. Further high voltage is impressed between the discharge electrodes 6 and the filters 8 by a high-voltage power source 5 and also the closed spaces 18 are provided in the filters 8 or to the rears thereof. As a result, granular substance can be filtered and collected without providing a bleeding means and therefore regulating the bleeding means and also can be sufficiently prevented from being again scattered.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a dust removal device that is applied to collect and remove particulate matter such as dust, fume, and mist contained in gas.

[Conventional technology]

Usually, the devices that collect and remove particulate matter from gas include (1) mechanical dust removal devices (Zyclone, bag filter, etc.), (2) electrical dust removal devices (electrostatic precipitators (hereinafter referred to as EP) ), etc.), but the above (1)
) can provide stable dust collection regardless of the physical properties of particulate matter of a given particle size, but it requires a large-capacity blower, and in terms of durability, equipment costs and operating costs are high. It has the disadvantage of being expensive. On the other hand, although the type (2) above requires a smaller capacity blower and is more durable than the type (1) above, the dust collection performance is easily affected by the electrical properties of particulate matter ( However, there is a drawback that general-purpose sizing that collects different types of particulate matter with the same performance is extremely difficult, and in order to prevent re-scattering of collected particulate matter, the main flow velocity is set to about 1rVS. Usually, the equipment capacity is large (it tends to be).

In order to realize a compact and high-performance dust removal means by incorporating the mutual advantages of the above-mentioned mechanical and electrical dust removal devices and compensating for their shortcomings, the following dust removal devices have been patented by this application. C patent application Sho 63-213735
No.) has been done.

That is, as shown in FIG. 7, a plurality of discharge electrodes 6 (two in case of taste 2 shown in the figure) are installed approximately parallel to the main gas flow in the casing 15 of the dust removal device having a gas population 1 and a gas outlet 3. A filtration device 8 with an added function as a ground electrode is provided parallel to the open '1itt pole 6 at a small distance (in a narrow R ising state), and a filter 8 is provided between the same discharge if pole 6 and the filtration device 8. A high voltage power supply 5 that applies high voltage to
has been established.

The space behind the filtration device 8 is connected to an air bleed pipe 16 having an air bleed blower 9, and the gas outlet 3 is connected to an air bleed duct 17 having an air blower 4. It is connected to the air extraction duct 17 on the upstream side.

In addition, in another type of device shown in FIG. 8, the air bleed blower 9 of the air bleed pipe 16 of the device shown in FIG. 6 is removed, and two gas outlets 3 are provided. A damper 10 for adjusting the pressure loss of the main gas flow is provided within the casing 15 .

As shown in FIG. 9, the filtration half stage 8 in both of the above dust removal devices includes a ground electrode 7 facing the discharge electrode 6, a ceramic filter that is a low pressure loss dielectric material, a porous dielectric material, polypropylene, etc. Fiberbed made up of
Alternatively, the dust removal filter 2 is made of a filter cloth for a bag filter, etc., and as the earth electrode 7, a material having a structure that forms an equipotential surface and does not obstruct the flow of gas, such as a wire mesh, is used.

In both the dust removal devices shown in FIGS. 7 and 8 above, the discharge electrode 6 and the filter device 8 are narrowly thrown.
When a high voltage is applied between the earth electrode 7 of the discharge chamber @
A high electric field is formed between the discharge electrode 6 and the filtration device 8, and a secondary flow a is generated from the discharge electrode 6 toward the filtration device 8 due to the action of the ion wind, as shown in the streamlines in FIG. 10, and the main gas flow is Particulate matter 1 in b moves toward the filtration device 8 under the influence of both the Coulomb force caused by the piezoelectric field and the secondary flow caused by the ion wind, and moves toward the filtration device 8 along with some of the gas flow.
It is filtered and collected as it passes through. The amount of gas passing through the filtration device 8 is optimally adjusted by the extraction means to prevent the collected particulate matter from being re-scattering.

As this air extraction means, the apparatus shown in FIG. 7 uses a blower 9 for air extraction, and the apparatus shown in FIG.
The amount of gas passing through is regulated.

The dust removal equipment shown in Figs. 7 and 8 above uses not only the Coulomb force caused by the electric field but also the secondary flow caused by the ion wind as a collection mechanism for particulate matter. The particulate matter collected by optimizing the amount of extracted air according to the main gas flow rate is guaranteed, and the influence of the electrical properties of particulate matter on dust collection performance is small. can prevent or suppress re-scattering. Therefore, since the main gas flow rate can be increased to about 5% or more, the device can be made more compact. At the same time, most of the processed gas is discharged from the gas outlet 3 without passing through the filtration half-stage, so the pressure drop is considerably lower than with mechanical dust removal devices such as bag filters ( It had many advantages, such as requiring a small capacity and reducing equipment costs, operating costs, and operating costs.

[Problem to be solved by the invention]

Although the dust removal apparatus shown in FIGS. 7 and 8 has many advantages as described above, it also has the following problems.

(1) A bleed means is required to control the amount of gas passing through the filtration device and prevent the collected particulate matter from scattering again. That is, the device shown in FIG. 7 requires an air bleed blower 9 as an air bleed means, and the device shown in FIG. 8 requires a damper 10 for pressure loss adjustment. Compared to dust collectors, it can be handled with a smaller device, but compared to electric dust collectors such as regular EP, equipment costs, operating costs, and additional maintenance items are required. .

(2) It is difficult to re-optimize the amount of extracted air. In particular, when the gas flow path in the casing is divided into multiple parts and a filtration device is installed for each flow path, it is necessary to This requires the installation of multiple blowers and pressure loss adjustment means such as dampers for each extraction pipe, which also requires increased equipment and operating costs and additional maintenance items.

(3) Requires air bleed piping. In other words, it requires extra equipment compared to normal EP and the like. In addition, especially when the gas flow path in the casing is divided into multiple parts and a filtration device is installed for each flow path, in order to optimize the amount of air bleed equally for each filtration device, the pressure drop of each bleed air piping must be It is necessary to take into account the pipe diameter and route, such as making sure that the

All of these problems are due to the addition of oil vapor means, and in order to solve them, it is necessary to find a means to replace the bleed air as a measure to prevent the collected particulate matter from being re-dispersed. desired.

The present invention attempts to solve the above problems.

[Means to solve the problem]

The present invention takes the following measures to solve the above problems.

That is, the dust removal device of the present invention includes a discharge electrode provided in a gas flow containing particulate matter, a filtration device provided opposite to the discharge electrode and having a counter electrode, and a filtration device provided between the discharge electrode and the filtration device. It was equipped with a high-voltage power source that applies a high voltage, and a closed space inside or behind the filtration device.

[For production]

In the dust removal device shown in FIGS. 7 and 8,
The streamline of the secondary flow mainly caused by the ionic wind is the 10th streamline.
The result will be as shown in the figure. Particulate matter in the gas that has flowed into the dust removal device is affected by the Coulomb force caused by the high electric field and the 10th
Under the influence of both of the secondary flows shown in the figure, it moves in the direction of the filtration device and flows into the filtration device 8 together with some of the gas flow.

The gas after particulate matter has been filtered and collected when passing through the filtration device 8 is approximately equivalent to the secondary flow gas that has flowed into the filtration device, and is extracted from the space 18 at the back of the filtration device by the above-described air extraction means. It was being bled.

In contrast, in the dust removal device of the present invention, by providing a closed space inside the filtration device or on the back side of the filtration device, the secondary flow of gas and particulate matter that flowed into the filtration device are removed from the filtration device. Secondary flow gas that enters the filtration device after particulate matter is filtered and collected while remaining in or passing through the filtration device. and the equivalent of gas is returned to the main gas stream from the filtration device again.

In the present invention, by changing the pressure drop of the filter that constitutes the filtration device (parameters such as open area ratio or porosity and thickness) and the volume of the closed space inside the filtration device or on the back thereof, the filtration device It is possible to change the residence time of the secondary flow gas in the closed space inside or at the back of the filtration device, and the residence time is selected so that a predetermined particulate matter can be filtered and collected within this residence time. Thereby, re-entrainment of particulate matter in the gas returning from the filtering means to the main gas flow is sufficiently prevented or suppressed.

As described above, the present invention allows particulate matter to be filtered and collected without providing an air extraction means (and therefore without adjusting this air extraction means), and sufficiently prevents and suppresses re-entrainment of the particulate matter. .

〔Example〕

A first embodiment of the present invention will be described with reference to FIGS. 1 and 2.

This embodiment differs from the dust removal device shown in FIGS. 7 and 8 in the following points, and the same parts are designated by the same reference numerals as in FIGS. 7 and 8 in FIG. with
The explanation will be omitted.

That is, in this embodiment, there is one gas outlet 3 on the outlet side of the casing 15, and the gas outlet 3 is connected to an air bleed pipe 16 having an air blower 4, and the air bleed pipe 16 as shown in FIG. Not prepared. In addition, the earth electrode 7 shown in FIG.
On the back side of the filtration device 8, which has a configuration similar to that in the dust removal device shown in FIGS. 18 are formed.

In this embodiment, a gas containing particulate matter is introduced from a gas population 1 into a space constituted by a discharge electrode 6 and a filtration device R8 arranged in a narrow spacing state in the dust removal device. The filtration device 8 includes a ground electrode 7 facing the discharge electrode 6 and a filter 8 for filtering and collecting particulate matter (see FIG. 9), and a high-voltage power supply 5 is connected between the discharge electrode 6 and the filtration device 8. A high voltage is being applied. Since the discharge electrode 6 and the filtration device 8 face each other with a narrow ising, a high electric field is formed and at the same time a large secondary flow due to the ionic wind is generated, as the streamlines are shown in Fig. 3. . Therefore, as shown in Fig. 2, particulate matter introduced into this space along with the main gas flow b is affected by both the Coulomb force caused by the electric field and the secondary flow caused by the ion wind. It moves in the direction of filtration device #8 and flows into the filtration device 8 together with the secondary gas flow a. At this time, the particulate matter in the charged gas forms an electric field due to its own electric charge, and is collected with high efficiency by the dust removal filter 2 of the filtration device 8 using the electrostatic force.

Pressure loss adjustment by changing the aperture ratio or porosity, thickness, etc. of the dust removal filter 2 in the above-mentioned filtration device 8;
and a closed space on the back side opposite to the main gas flow of the filtration device 8] By appropriately combining the volume adjustment of 8, the secondary gas flow containing particulate matter that has flowed into the filtration device 8 space 18 inside or on the back of the filtration device 8 for a certain period of time.
Particulate matter is collected by filtration when passing through the filtration device 8 during the residence time. Gas equivalent to the secondary stream gas that then entered the filtration device 8 returns from the filtration device 8 to the main gas stream.

As described above, in this embodiment, the dust removal filter 2 and the back space 18 are selected so that the filtration and collection efficiency meets the requirements, so that when the secondary flow gas returns from the filtration device 8 to the main gas flow, re-entrainment of particles is sufficiently prevented or suppressed.

Second to fourth embodiments of the present invention will be explained with reference to FIGS. 4 to 6.

In the second embodiment shown in FIG. 4, a closed space is provided at the back of each filtration device 8, that is, a closed space 18 is provided at the back in the first embodiment. The space is also filled with a filtration device 8.

Further, in the third embodiment shown in FIG. 5, the main gas flow path is divided into a plurality of sections, and a closed space 18 on the back side is shared by a plurality of filtration devices 8. There is.

Furthermore, in the fourth embodiment shown in FIG. 6, there is no closed space at the rear of the filtration device, and the filtration device #8 itself is shared by a plurality of main gas flow paths. That is, the space in which the back space 18 was installed in the third embodiment shown in FIG. 5 is also filled with the filtration device 8.

These second to fourth embodiments can also provide the same functions and effects as the first embodiment.

In addition, in each of the above embodiments, the counter electrode (earth electrode) and the dust removal filter in the filtration device are provided separately, but a filtration device in which both are integrated using a conductive filter can also be used. .

〔Effect of the invention〕

As explained above, the present invention eliminates the need for air extraction means in a dust removal device in which a high voltage is applied to a discharge electrode and a filtration device provided opposite thereto and having a counter electrode. It is possible to prevent the re-scattering of the particulate matter collected by the air extraction method, eliminate the need for equipment costs, operating costs, and maintenance costs required for air extraction means, and maintain dust removal efficiency.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the first embodiment of the present invention, FIG. 2 is a longitudinal cross-sectional view of the filtration device of the same embodiment and the closed space on the back thereof, and FIG. 3 is an ion ion diagram of the same embodiment. 4 to 6 are longitudinal cross-sectional views of main parts of the second to fourth embodiments of the present invention, and FIGS. 7 and 8 are illustrations of secondary flow streamline patterns caused by wind, respectively. An explanatory diagram of the dust removal device related to the applicant's patent application (Japanese Patent Application No. 63-213735), Fig. 9 is an explanatory diagram showing the filtration device part of the dust removal device, and Fig. 10 is an illustration of the dust removal device in the same FIG. 2 is an explanatory diagram of an a-turn, a streamline of a secondary flow caused by an ion wind. 1... Gas inlet, 2... Dust removal filter. 3...Gas outlet, 4...Blower. 5...High voltage power supply, 6...Discharge electrode. 7... Counter electrode, 8... Filtration device. 15...Casing, 17...Exhaust duct. 18... Closed space at the back, 19... Partition wall. a...Secondary flow, b...Main gas flow.

Claims (1)

[Claims] a discharge electrode placed in a gas stream containing particulate matter;
A filtration device provided opposite to the discharge electrode and having a counter electrode, a high-voltage power source that applies a high voltage between the discharge electrode and the filtration device, and a closed space inside or behind the filtration device. Features dust removal equipment.