JPS5941776B2 - Collected dust removal method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for removing collected dust in a dust collector in which at least one dust collection passage between narrow poles is arranged in parallel.

In recent years, electrostatic precipitators equipped with a large number of dust collection passages between narrow electrodes have been developed in such a way that the electrostatic field for collecting dust in the dust collection passages can be configured with a voltage as low as several to several tens of degrees. The supply of dust-containing gas to the dust collection passage where an electrostatic field is formed is
Because it can perform at high speeds of 10 mAec to 10 mAec, it is expected to reduce the equipment price and maintenance costs, as well as reduce the size of the equipment. It is attracting attention at sites where dust is generated.

However, this device has a dust collection passage of 10 to 50rr.
Since the distance between the poles is as narrow as R, it is very difficult to remove the dust that is collected and accumulated in the dust collection passage over time.

That is, the removal of collected dust in this type of dust collection passage is generally performed mechanically by holding a dust removal mechanism consisting of sliding members such as scrapers and brushes so as to be movable up and down between each passage. If the dust collection path becomes even slightly longer, the sliding contact member will flex and stable sliding contact will not be possible.
As a result, reliable removal of collected powder could not be expected.

In addition, since a large number of dust collection passages consisting of the narrow electrode spaces are generally arranged in parallel, the structure of the removal mechanism is inevitably complicated, so that the workability is reduced when replacing the sliding contact member due to wear. It was extremely bad.

Furthermore, it is difficult to maintain the insulation of the removal mechanism during normal operation, and in some cases, a blind spot is created in the dust collection passage, causing a reduction in dust collection efficiency.

Recently, however, attempts have been made to use a jetted liquid stream as a means for removing the collected dust in this type of narrow dust collection passage.

It is true that the removal means using the jetted liquid stream is improved in terms of reliability and simplicity compared to conventional removal means, but it requires a liquid supply source (mainly a water source), so it is difficult to install. This method could not necessarily be said to be a satisfactory solution, as it had unavoidable problems such as space restrictions and difficulty in post-processing (separation and recovery) of the collected dust. .

As explained above, this type of device consisting of a dust collection passage between narrow poles has various features compared to one between wide poles, but there are still problems to be solved in terms of removing the collected dust. Currently, it is not put into practical use much because of the remaining problems.

Therefore, the present inventors have worked hard to put into practical use a device consisting of the dust collection passage between the narrow electrodes, which can be expected to be optimally used in dust generating sites where the processing air volume is large and the installation area is limited. As a result of repeated research, by specifying the dust to be treated as non-adhesive dust, we were able to remove the dust collected on the dust collection passage surface during the treatment. It is extremely simple, just by circulating the gas remaining in the dust passage and injecting this circulating gas flow toward the dust collection surface in the dust collection passage in a direction almost parallel to the flow direction of the dust-containing gas. It was also found that it can be removed reliably.

According to the present invention based on the above knowledge, there is provided a device for removing collected dust in an electrostatic precipitator in which at least one dust collection passage between narrow electrodes is arranged in parallel, the removal device comprising: an opening/closing mechanism for closing both ends of the dust passage; a circulation passage for sucking the gas in the sealed dust collection passage from one end of the dust collection passage and reintroducing it from the other end; and the circulation passage. a circulating gas flow forming mechanism disposed at an appropriate location, and a mechanism for injecting the circulating gas flow toward the dust collection surface in the dust collection passageway in a direction substantially parallel to the flow direction of the dust-containing gas. There is provided a collected dust removal device characterized by comprising an injection mechanism.

In the present invention, the narrow inter-electrode dust collecting passage generally refers to those with an inter-electrode distance of 5 to 60 degrees.

Usually, a high voltage of approximately 5 to 30 KV is applied to one pole forming the narrow inter-electrode dust collection passage,
This creates a dust-collecting electrostatic field between the other pole and the other pole.

Furthermore, the combination of the pair of electrodes forming the dust collection passage is
Plate-to-plate or wire-to-plate is common.

In this combination, when the former flat plate-to-flat type is used, unlike the latter wire-to-flat type, since almost no charging action takes place in the dust collection passage, the dust in the exhaust gas is It is necessary to ionize the dust in advance before supplying it to the dust collecting passage.

The charge range for ionizing dust in this gas is
Any structure can be adopted without any restriction as long as it generates active and stable corona discharge between the charged electrode and the counter electrode.

It is to be noted that, as the remaining charging electrode constituting the charging region, a conductive thin wire having one or less conductive wires or a conductive member having a sharpened charging electrode surface facing the counter electrode is preferably employed.

An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a partial systematic sectional view illustrating a device for removing collected dust in a dust collector 21 in which at least one dust collection passage 1 between narrow electrodes is arranged in parallel, The device is characterized by opening/closing mechanisms 32 and 33 for closing both ends of the dust collection passage 1, and for sucking the gas inside the sealed dust collection passage 1 from one end of the dust collection passage 1 and from the other end. a circulating gas flow forming mechanism 6 such as a fan or blower disposed at an appropriate location in the circulating gas flow, and a circulating gas flow forming mechanism 6 for reintroducing the circulating gas into the dust collection channel 1. It is composed of a flat dust collecting electrode 23 and a high potential sustaining electrode 26, that is, an injection mechanism 35 for injecting the dust toward the dust collecting surface in a direction substantially parallel to the flow direction of the dust-containing gas.

The dust collection passage 1 in this embodiment includes a flat dust collection electrode 23 maintained at ground potential, and a 10rrr I
It is formed of a plate-shaped high potential sustaining electrode 26 that faces apart from each other with a gap of about n, and a high voltage of about 8 to 10 KV is electrically connected to the high voltage generator 24 via a high voltage cable 25. However, nothing is limited to this,
A flat dust-collecting electrode maintained at ground potential, and facing the flat dust-collecting electrode with a gap of about 10 m.
It may also be configured by a thin wire-shaped charged electrode having a diameter of less than -m, preferably less than 0.8 mm, at which a voltage as high as that of a mushroom can be maintained.

In addition, in this embodiment, as described above, since the dust collection passage 1 is formed by a combination of flat plates, a thin wire-shaped charging electrode 27 with a diameter of about 0.8 rIun is provided on the front side of the dust collection passage 1.
and a grid-shaped counter electrode 28 which faces the charging electrode 27 at a distance of about 10 to 20 rrvn and is maintained at ground potential.

If a lattice-like member is used as the counter electrode 28, various effects such as rectification of the gas flow and coagulation and coarsening of fine dust in the gas flow can be expected, but the configuration of the charged region 29 in the present invention is not limited to this in any way. Of course, any structure can be adopted as long as it is possible to obtain a positive and stable corona discharge between the charging electrode 27 and the counter electrode 28.

Usually, a high voltage of about 5 to 20 KV is applied to the charging electrode 27 via a high voltage cable 30 to a high voltage generator 31.
Supplied by

Therefore, the dust-containing gas formed in a dust generation source (not shown) such as a tunnel is supplied through the dust into the main body of the dust collector 21, which is equipped with a large number of dust collection passages 1 arranged in parallel. It is cleaned by electrostatic action.

In this cleaning process of dust-containing gas, in order to maintain a constant collection efficiency at all times, as is already known, the flat dust collecting electrode 23 constituting the dust collecting passage 1,
It is necessary to appropriately remove the dust that is collected and deposited over time on the flat high-potential sustaining electrode 26 which is spaced apart from and faces the flat dust collecting electrode 23.

As mentioned above, the feature of removing the collected dust in the present invention is that the collected dust is a non-adhesive substance, and both ends of the dust collecting passage 1 are closed by closing the opening/closing mechanisms 32 and 33. The flow of the dust-containing gas is cut off, a circulating gas flow is formed in the sealed dust collecting passage 1 by the circulating passage 5 and the circulating gas flow forming mechanism 6, and this circulating gas flow is passed through the dust collecting passage 1. The collected dust is blown away by spraying from the jetting mechanism 35 toward the flat dust collecting electrode 23 and the high potential maintaining electrode 26, that is, the dust collecting surface in a direction substantially parallel to the flow direction of the dust-containing gas. It's about doing.

As described above, the circulating gas flow is formed by removing the gas present in the dust collecting passage 1 from one end of the dust collecting passage 1 when the dust collecting passage 1 is sealed and the supply of high voltage is stopped. This is carried out by a circulating gas flow forming mechanism 6 disposed in the circulation passage 5 of the reservoir, which is sucked in and reintroduced from the other end.

Usually, the circulating gas flow is supplied to the dust collection passage 1 at a flow rate of at least 1 mAec or more, thereby removing the collected dust from the dust collection passage surface.

Note that when the dust removed from the dust collection passage surface by the circulating gas flow is directly discharged to the outside from the lower part of the dust collection passage 1, the wind speed of the circulating gas flow flowing inside the dust collection passage 1 is not very high. is preferable.

That is, since the dust removed from the dust collection passage surface is agglomerated and coarsened, if the wind speed is slow, most of it will settle in the lower part 13 due to its own weight, and it will not settle in the lower part 13 but will remain in the circulating gas flow. This is because even if it is mixed into the water, most of it will settle in the lower part 13 during the circulation process.

In the removal process of the collected dust, it is preferable to perform the process by slowing down the flow rate of the circulating gas flow over time rather than by maintaining the flow rate constant, because the dust can be collected reliably and in a short time.

The dust settled in the lower part 13 is collected in a dust collection tank 15 through a so-called porous member 14 formed in the lower part 13 such as a punching metal, a wire mesh, a lattice member, etc., and is then collected by the vibration action of a vibrator 16. It is collected in one place and then discharged to the outside as appropriate.

In this embodiment, the collected dust is removed using the circulating gas flow when the supply of dust-containing gas and high voltage to the dust collection passage 1 is cut off, and the inside of the main body including the dust collection passage 1 is sealed. Since the removal is carried out under the same conditions, the collected dust can be easily and reliably removed.

In order to cut off the supply of dust-containing gas to the dust collection passage 1 and to seal the passage 1, the damper 32 provided in the duct on the gas introduction side and the other damper 33 provided on the gas discharge side are closed. done by.

Further, the high voltage supply is cut off by controlling the input side or the output side of the high voltage generator 24.

Furthermore, dampers 19,
20 is arranged so that the gas in the dust collection passage is circulated through the circulation passage 5 only during the removal process of the collected dust.

Each operation of the dampers 32, 33, 19, 20, the high voltage generator 24, and the fan 6 is performed by monitoring the state of adhesion of the dust collected in the dust collection passage 1 over time to maintain a constant state. When this happens, a control signal is generated to automatically perform related controls.

Monitoring of the collected dust related to the change over time is carried out using the dust collecting electrode 2.
3 to detect changes in discharge current by installing an ammeter;
Alternatively, this can be carried out by known means such as arranging a concentration meter on the exhaust gas exhaust side to detect changes in the exhaust gas concentration.

Note that, as described above, the collected dust in the present invention is removed while the cleaning operation of the dust-containing gas is interrupted during the processing, so normally at least two or more devices 21 having the above structure are installed in parallel. It is preferable to use a selection operation.

When the removal process of the collected dust is completed, the supply of dust-containing gas and high voltage to the dust collecting passage 1 is automatically restored, thereby restarting the groove-forming process of the dust-containing gas. be done.

In this case, it is preferable to supply high voltage in advance before supplying the dust-containing gas in order to prevent the dust from scattering again when restarting the operation.

In addition, in order to more effectively remove and discharge the collected dust, as shown in this embodiment, the circulation passage 5
Gas cleaning mechanism 2 for cleaning the suction gas flow during the
2 is preferably provided, thereby actively separating and collecting dust in the circulating gas flow.

That is, the dust in the dust collection passage 1 is carried out to the outside of the dust collection passage 1 by the circulation gas flow, and the dust floating in the circulation gas flow is separated and collected by the gas cleaning mechanism 22 disposed in the middle of the circulation passage 5. Since there is no need to consider settling and discharging the dust in the dust collection passage 1, the wind speed of the circulating gas flow formed in the dust collection passage 1 can be further increased. This is because the dust on the dust passage surface can be removed faster and more reliably.

The gas cleaning mechanism 22 in the present invention is a general term for various gas cleaning mechanisms known per se, such as a back filter, an electrostatic precipitator, and a cyclone.

In particular, in the various gas cleaning mechanisms 22 used in the present invention, the dust mixed into the circulating gas flow is aggregated and coarsened, and the processing air volume is relatively small. Since there is no need to clean the gas, it can be significantly miniaturized and have a relatively simple structure.

Further, even if the device 21 having a large number of dust collection passages 1 between the narrow electrodes is unitized and installed in multiple units, only one mechanism 22 can be provided by performing a selective switching operation.

In this embodiment, a gas cleaning mechanism 2 is provided in the circulation passage 5.
2 is arranged so that the dust in the circulating gas flow supplied to the dust collection passage 1 is not only settled due to its own weight in the dust collection passage 1 part, but also is actively separated and collected by the gas cleaning mechanism 22 part. Therefore, the circulating gas flow supplied to the dust collection passage 1 can be effectively injected through the injection mechanism 35 consisting of the injection port 34 having a relatively small diameter, and as a result, even more effective removal can be achieved.

Further, by disposing the gas purifying mechanism 22 in the circulation passage 5, the flow rate of the partially circulated gas flow can be made relatively high, and furthermore,
Since there is no need to slow down the flow rate over time, the processing time can be significantly shortened.

The injection mechanism 35 in this embodiment is constructed by arranging a plurality of pipe materials having injection ports 34 corresponding to the number of dust collection passages 1 in multiple stages.

Thermal theory, the structure of the injection mechanism 35 in the present invention is not limited to this, and various structures can be adopted.

Typically, the injection mechanism 35 delivers at least ], m/sec.
Circulating gas is injected at the above flow rate.

In addition, in order to expect reliable and effective removal of the injected gas flow with a smaller air volume, the injection mechanism 35 is variable.
In some cases, it is injected as a fluctuating flow, and the choice is free and not limited to one.

Note that the circulation passage 5 is provided with a control valve 36 for adjusting the balance between the suction amount and the discharge (injection) amount of gas.

The device of the present invention based on the above-mentioned technical idea is suitable for use in actual automobile tunnels, where the processing air volume is extremely large, the main component of dust in the exhaust gas is ash, and the area occupied by the device and the water source are limited. When implemented with a dust collector, the characteristics of the device consisting of a dust collection passage between narrow electrodes can be maximized, and the collected dust, which has traditionally been considered extremely difficult with this type of device, can be removed reliably with a simple method. And it was easy to do.

In addition, in the present invention, as the gas for removing the collected dust, the gas remaining in the main body of the device is used for processing, etc., without directly using the atmosphere whose humidity changes greatly depending on the weather such as rain. There was no need for a gas drying device, and the removal process could always be performed under optimal conditions regardless of weather changes.

In particular, when a back filter was employed as the gas cleaning mechanism 22, the effect of selecting the gas for removing the collected dust was remarkable.

[Brief explanation of the drawing]

FIG. 1 is a partial systematic sectional view showing an embodiment of the present invention, in which the side illumination numeral 1 indicates a dust collection passage consisting of a narrow gap, 5 a circulation passage;
6 is a circulating gas flow forming mechanism, 21 is a dust collector, 22 is a gas cleaning mechanism, 23 is a flat dust collection electrode, 24.31 is a high voltage generator, 26 is a high potential maintenance electrode, 32 and 33 are opening/closing mechanisms , 35 indicate injection mechanisms, respectively.

Claims (1)

[Scope of Claims] 1. A device for removing collected dust in an electrostatic precipitator in which at least one dust collection passage between narrow electrodes is arranged in parallel, the removal device comprising: an opening/closing mechanism for a reservoir that closes the dust collection passage; a circulation passage for sucking the gas in the sealed dust collection passage from one end of the dust collection passage and reintroducing it from the other end; A circulating gas flow forming mechanism is provided, and an injection mechanism that injects the circulating gas flow toward a dust collection surface in the dust collection passageway in a direction substantially parallel to the flow direction of the dust-containing gas. A device for removing collected dust. 2. The device according to claim 1, characterized in that a gas cleaning mechanism for cleaning the circulating gas flow is disposed at an appropriate location in the circulation passage. 3. The apparatus according to claim 1, wherein the injection mechanism is an injection mechanism for ejecting the gas body as a fluctuating flow.