JP2009078215A - Dry electrostatic precipitator and its operation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dry electrostatic dust precipitator with structure completely preventing re-scattering of dust generated due to electrode hammering, and its operation method. <P>SOLUTION: The dry electrostatic dust precipitator has a plurality of dust precipitation vessels 8 which are disposed in the precipitator, each vessel being provided with: an inlet pipe 7 introducing exhaust gas into the vessel; discharge electrodes 2 provided in the vessel and charging dust in the exhaust gas; dust collecting electrodes 1 provided in the vessel and collecting the charged dust; a hopper 9 provided at a bottom of the vessel and recovering dust dropping from the dust collection electrodes; an outlet pipe 11 leading the exhaust gas cleaned in the vessel out of the vessel; and a shielding means shielding the gas flow entering the vessel and gas flow led out of the vessel. The inlet pipes 7 provided in the respective dust collection vessels 8 are connected with each other, and the outlet pipes 11 provided in the respective dust collection vessels 8 are connected with each other. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a dry electrostatic precipitator and a method for operating the same, and more particularly, to a dry electrostatic precipitator having a structure capable of completely preventing re-scattering of dust generated when a dust collecting electrode is beaten, and a method for operating the same. .

The dry electrostatic precipitator is configured to cause exhaust gas to flow between a discharge electrode to which a high voltage is applied and a dust collection electrode, and to charge dust contained in the exhaust gas by corona discharge generated by the application of the high voltage. Is collected at the dust collecting pole by Coulomb force.
The dust collected by the dust collecting electrode is subjected to a mechanical impact such as smashing a predetermined portion of the dust collecting electrode with a hammer or vibrating with a vibrator (hereinafter referred to as 槌). It is called a hammer.) It is peeled off from the dust collecting electrode, dropped and collected by a hopper installed at the bottom of the dust collecting container.

  By the way, since the dry electrostatic precipitator needs to continuously process the exhaust gas flowing in one after another, the latter dust recovery is performed in parallel with the former dust collection. Therefore, when the dust collecting electrode is beaten in order to collect dust, the dust separated from the dust collecting electrode is scattered on the gas flow again, and the dust collecting efficiency is lowered (for example, Patent Documents 1 and 2). reference).

  For this reason, a method of blocking a part of the flow of exhaust gas using a shielding means such as a curtain or a damper provided at the entrance or exit of the dust collection space (see, for example, Patent Documents 1 and 2), and the amount of re-scattering Various improvement measures such as a method of designing an apparatus, a method of providing fins on a dust collecting electrode, and a method of striking so as not to disperse dust have been proposed.

  Among these, in Patent Document 1, in order to prevent the dust separated from the dust collection electrode from getting on the gas flow again, as shown in FIG. 6, in the vicinity of the upstream end or the downstream end of the gas flow, An electrostatic precipitator is disclosed in which a movable curtain that blocks part of the gas flow is arranged. In addition, FIG. 6 is a figure at the time of arrange | positioning a movable curtain in the downstream edge part vicinity of a gas flow.

  However, in the electrostatic precipitator described in Patent Document 1, a region in which the gas flow is blocked in order to prevent re-scattering of the dust, that is, a region in which dust is collected by striking the dust collecting electrode, and the gas flow The area where the dust is collected and the area where dust is collected by the dust collecting electrode is located in the same dust collecting space. It cannot be a system. Therefore, as shown in FIG. 6, there is a detour of the gas flow at the upper or lower portion of the area where the gas flow is blocked using the movable curtain, and the dust separated from the dust collecting electrode by the strike is detoured. It will respray on the gas flow through the road. That is, an electrostatic precipitator that cuts off part of the gas flow using a movable curtain or the like has a limit in the ability to cut off the gas flow, and cannot completely prevent dust re-scattering.

In Patent Document 1, a movable curtain may be disposed in the vicinity of the middle stream side end or downstream end of the gas flow. In this case, even if dust re-scatters in the middle stream part or the downstream part. However, it is described that the re-scattered dust is collected by the dust collecting electrode located downstream, so that the re-scattering of dust is not a big problem (see paragraph [0038] of Patent Document 1). In the electric dust collector described in Patent Document 1, dust is re-scattered in a predetermined case, and the dust collecting capability is required as the gas flow is further downstream. It means nothing but design.
Japanese Patent Laid-Open No. 7-299387 Paragraphs [0004] to [0005] of JP-A-11-319630

  The problem to be solved by the present invention is to provide a dry electrostatic precipitator having a structure capable of completely preventing re-scattering of dust generated when the dust collecting electrode is beaten, and an operating method thereof.

  The present inventor has obtained the following technical knowledge as a result of various experimental studies and theoretical studies to solve the above problems.

(A) As described above, the area where dust is collected by striking the dust collection electrode (hereinafter referred to as the collection area) and the area where dust is collected by the dust collection electrode (hereinafter referred to as collection area). Are collected in the same dust collection space, so that dust is scattered from the collection area to the collection area. Each of them has a discharge electrode and a collection electrode inside. If a plurality of dust collecting containers each having a shielding means for shielding a gas flow introduced into the container and a gas flow led out of the container are arranged as shown in FIG. Since the collection area can be separated, dust re-scattering can be completely prevented.

(B) For example, the shielding means provided in the leftmost dust collecting container (hereinafter referred to as a No1 container for convenience) in FIG. 1 is closed and the gas flow introduced into the No1 container and outside the No1 container Since the No1 container can be a closed system when the gas flow to be derived is stopped, even if the dust collected on the dust collecting electrode is peeled off and dropped inside the No1 container, The dust should not be scattered outside the No1 container. In addition, the other five dust collection containers should be able to collect dust without being affected by dust collection performed inside the No1 container.

(C) Since a plurality of dust collection containers can be made into a closed system by the above operation, the dust collection efficiency of the entire apparatus is improved by sequentially repeating dust collection for the plurality of dust collection containers. What can be done.

(D) As described above, the electrostatic precipitator described in Patent Document 1 requires a higher dust collecting capacity toward the downstream of the gas flow, and a device design corresponding to this is required. If the dust collector has a plurality of dust collection containers, each of which can be a closed system, the device design to achieve the target dust collection efficiency should be easy.

(E) Specifically, the dust collecting apparatus in which a plurality of dust collecting containers, each of which can be a closed system using shielding means for shielding the gas flow, can completely prevent dust re-scattering. A design philosophy that gives uniform dust collection performance to the dust collection container. For example, when six dust collection containers are arranged as shown in FIG. 1, if one of them collects dust, the remaining five will be responsible for collecting dust. , Design to give each dust collection container a dust collection performance of 20% (= 100% / 5 units). Similarly, when three dust collection containers are arranged, it is necessary to design each dust collection container with 50% dust collection performance when two dust collection containers are arranged.

  Based on the above findings, the present inventor has conceived of a dry electrostatic precipitator having a structure capable of completely preventing re-scattering of dust generated when the dust collecting electrode is beaten, and an operation method thereof. The gist is as follows.

(1) An inlet pipe for introducing exhaust gas into the container, a discharge electrode provided in the container for charging dust in the exhaust gas, and a dust collecting electrode provided in the container for collecting charged dust A hopper provided at the bottom of the container for collecting the dust dropped from the dust collection electrode, an outlet pipe for leading the exhaust gas purified inside the container to the outside of the container, a gas flow introduced into the container, and A plurality of dust collecting containers provided with shielding means for shielding the gas flow led out to the outside of the container are arranged, inlet pipes provided in each dust collecting container are connected to each other, and outlet pipes provided in each dust collecting container are mutually connected Connected dry electrostatic precipitator.

(2) An inlet pipe for introducing exhaust gas into the container, a discharge electrode provided in the container for charging the dust in the exhaust gas, and a dust collecting electrode provided in the container for collecting the charged dust A hopper provided at the bottom of the container for collecting the dust dropped from the dust collection electrode, an outlet pipe for leading the exhaust gas purified inside the container to the outside of the container, a gas flow introduced into the container, and A plurality of dust collecting containers provided with shielding means for shielding the gas flow led out to the outside of the container are arranged, inlet pipes provided in each dust collecting container are connected to each other, and outlet pipes provided in each dust collecting container are mutually connected A method of operating a connected dry electrostatic precipitator, wherein a gas flow introduced into the dust collecting container by closing a shielding means of any one of a plurality of dust collecting containers arranged and the dust collecting Gas flow leading out of container In a state where the dust collecting container is stopped, the dust collecting electrode provided in the dust collecting container is beaten to drop the dust collected by the dust collecting electrode, and the shielding means closed after a predetermined time has elapsed is opened. A method for operating a dry electrostatic precipitator that sequentially repeats a plurality of dust collecting containers.

(A) The dry electrostatic precipitator according to the present invention has a structure in which a plurality of dust collecting containers each including a discharge electrode and a dust collecting electrode are arranged, and each dust collecting container has a gas flow introduced into the container. And shielding means for shielding the gas flow led out of the container.
Thus, the dry electrostatic precipitator according to the present invention closes the shielding means of any one of the plurality of disposed dust collecting containers, thereby introducing the shielding means into the closed dust collecting container. The gas flow and the gas flow led out of the dust collecting container can be stopped.
Therefore, even if the dust collecting electrode is beaten inside the dust collecting container where the gas flow is stopped and dust accumulated on the dust collecting electrode is peeled off and dropped, the dust will not be scattered outside the container. For this reason, in other dust collection containers, stable dust collection can be performed without being affected by dust collection performed inside the container where the gas flow is stopped.
That is, the dry electrostatic precipitator according to the present invention can completely prevent the dust from re-scattering when the dust collecting electrode is beaten, thereby exhibiting high dust collecting efficiency.

(B) The dry electrostatic precipitator according to the present invention can completely prevent the re-scattering of dust generated when the dust collecting electrode is beaten. Therefore, unlike the dry electrostatic precipitator according to the prior art, the target The device design for achieving the dust collection efficiency is easy.
That is, in the dry electrostatic precipitator according to the prior art, since dust re-scatters, a higher dust collection capacity is required downstream of the gas flow, and a complicated device design corresponding to this is required. Since the dry electrostatic precipitator according to the present invention can completely prevent dust from re-scattering, the dust collection performance of each dust collection container can be made uniform. For this reason, the dry electrostatic precipitator according to the present invention is very easy to design for achieving the target dust collection efficiency.
Moreover, the dry electric dust collector which concerns on this invention which repeats the operation | movement which transfers the said dust collection container to dust collection after completion | finish of dust collection of any one dust collection container, and collects the dust of the next dust collection container is repeated. According to this operating method, since the dust collection performance of each dust collection container is uniform, stable operation is possible, and the dust collection efficiency of the entire apparatus can be improved.

(C) The dry electrostatic precipitator according to the present invention can effectively use the purified exhaust gas, unlike the dry electrostatic precipitator according to the prior art.
That is, the dry electrostatic precipitator according to the prior art has limited exhaust gas cleaning performance because dust re-scatters, and when the cleaned exhaust gas is used as an industrial combustion gas, the gas is burned. Burner may be worn or damaged. Further, when recovering pressure from the cleaned exhaust gas, it is necessary to operate with low efficiency so that the blades of the turbine are not worn or damaged.
On the other hand, since the dry electrostatic precipitator according to the present invention can completely prevent dust from re-scattering, the exhaust gas is highly clean and collects pressure even when used as industrial combustion gas. Even in this case, the cleaned exhaust gas can be used effectively.

Hereinafter, the best mode for carrying out the present invention will be described with reference to FIGS.
FIG. 1 is a schematic view of a dry electrostatic precipitator according to the present invention. As shown in FIG. 1, the dry electrostatic precipitator according to the present invention is completely different from the structure of the dry electrostatic precipitator according to the prior art, and has a structure in which a plurality of dust collecting containers 8 are arranged.

  As shown in FIG. 1, the inlet pipes 7 included in the respective dust collection containers 8 are connected to each other. Further, the outlet pipes 11 included in each dust collecting container are also connected to each other. More specifically, all of the inlet pipes 7 included in each dust collecting container are connected to the inlet dust collecting main pipe 6, and all of the outlet pipes 11 included in each dust collecting container are connected to the outlet cleaning main pipe 13. The Exhaust gas discharged from industrial furnaces such as a heating furnace, a combustion furnace, a reduction furnace, a melting furnace, and a drying furnace passes through an inlet dust collecting main pipe 6 and an inlet pipe 7 connected to the main pipe, and a dust collecting container 8. The dust is collected and collected inside the dust collecting container 8. Then, the exhaust gas cleaned inside the container is led out of the dust collecting container 8 through the outlet pipe 11, and is discharged out of the dry electric dust collector through the outlet cleaning main pipe 13.

  FIG. 2 is a side sectional view of the dust collecting container 8 provided in the dry electrostatic precipitator according to the present invention. As shown in FIG. 2, the exhaust gas flowing through the inlet dust collecting main pipe 6 descends to the bottom of the container through the inlet pipe 7, and is rectified by the rectifier 10 provided at the bottom of the container.

  FIG. 3 is a layout view of the discharge electrode 2 and the dust collecting electrode 1, and is a cross-sectional view taken along the line BB in FIG. 4 is a plan view seen from the direction A in FIG. Although the cross-sectional shape of the dust collecting container 8 is not limited to a circular shape, when a dust collecting container having a circular cross-sectional shape is used, the discharge electrode 2 for charging dust in the exhaust gas is as shown in FIG. It is desirable to arrange them radially around the inlet tube 7. By disposing the discharge electrodes 2 radially around the inlet tube 7, the charging efficiency of dust is improved. The voltage application to the discharge electrode 2 is supplied from a high-voltage DC power source 3 shown in FIG.

  As shown in FIG. 3, the dust collection electrode 1 is disposed so as to surround the discharge electrode 2 and form a cellular dust collection space. In addition, the dust collection electrode 1 is arranged so that the discharge electrode 2 is positioned at the center of the cellular dust collection space. By arranging the discharge electrode at the center of the cellular dust collection space, dust collection efficiency is improved. In the process in which the exhaust gas rectified by the rectifier rises up the cellular dust collection space, the dust contained in the exhaust gas is charged by the corona discharge generated by the application of a high voltage, and the charged dust becomes coulomb. It is collected at the dust collecting electrode 1 by force. The dust collected by the dust collecting electrode 1 is peeled off and dropped from the dust collecting electrode by striking the dust collecting electrode 1 and collected by the hopper 9 installed at the bottom of the dust collecting container.

As shielding means for shielding the gas flow introduced into the container and the gas flow led out of the container, it is desirable to use a damper, a partition valve, a butterfly valve or the like.
Further, it is desirable to install the shielding means on either or both of the inlet pipe 7 and the outlet pipe 11. When the shielding means is installed in the inlet pipe 7, the gas flow introduced into the container is shut off, so that the gas flow led out of the container is also shielded. On the other hand, when the shielding means is installed in the outlet pipe 11, the gas flow led out to the outside of the container is blocked, so that the gas flow introduced into the container is also shielded. 1 and 2 are examples in which a damper 12 is installed in the outlet pipe 11.

  The dry electrostatic precipitator according to the present invention is completely different from the structure of the dry electrostatic precipitator according to the prior art as described above, and a plurality of dust collecting containers 8 including the discharge electrode 2 and the dust collecting electrode 1 are arranged inside. Structure. Each dust collecting container 8 includes shielding means for shielding the gas flow introduced into the container and the gas flow led out of the container. Therefore, the dry electrostatic precipitator according to the present invention closes the blocking means of any one of the plurality of arranged dust collecting containers 8 so that the closing means is closed inside the dust collecting container. The gas flow to be introduced and the gas flow led out to the outside of the dust collecting container can be stopped.

  In other words, in the dry electrostatic precipitator according to the present invention, the gas flow introduced into the dust collecting container by closing the shielding means of any one of the plurality of arranged dust collecting containers 8. In a state where the gas flow led out of the dust collecting container is stopped, the dust collecting electrode 1 provided in the dust collecting container is beaten to drop the dust collected by the dust collecting electrode.

  When the dust collecting electrode 1 is beaten, it is desirable to stop the voltage application from the high-voltage DC power source to the discharge electrode 2. That is, it is desirable to strike the dust collecting electrode 1 in a state where dust collection at the dust collecting electrode 1 is stopped. There is no gas flow in the vicinity of the dust collecting electrode due to the blocking of the shielding means, and most of the dust separated from the dust collecting electrode 1 passes through a predetermined settling time due to its own weight, and then a hopper installed at the bottom of the dust collecting container 8. It drops to 9 and accumulates.

  However, since the dust of some fine particles has a low descending speed, it does not descend to the hopper within the above calming time and floats near the dust collecting electrode. For this reason, in order to prevent the floating fine particle dust from re-scattering, it is desirable to start voltage application before opening the shielding means. After the voltage is applied, the fine particle dust is collected again by the dust collecting electrode 1, so that the fine particle dust floating near the dust collecting electrode is not scattered again. Then, the shielding means closed after a predetermined time has elapsed is opened, gas is introduced into the dust collecting container 8, and dust collection is resumed.

  As described above, the dry electrostatic precipitator according to the present invention strikes the dust collecting electrode 1 inside the dust collecting container 8 in which the gas flow is stopped, and peels and drops the dust accumulated on the dust collecting electrode. Even if this occurs, the dust does not scatter outside the container. Therefore, in other dust collection containers, stable dust collection can be performed without being affected by dust collection performed inside the container where the gas flow is stopped. That is, the dry electrostatic precipitator according to the present invention can completely prevent the dust from re-scattering when the dust collecting electrode is beaten, thereby exhibiting high dust collecting efficiency.

  In addition, the dry electrostatic precipitator according to the prior art has limited exhaust gas cleaning performance because dust re-scatters, and when the cleaned exhaust gas is used as an industrial combustion gas, the gas is burned. The burner may be worn and damaged, and when recovering pressure from the cleaned exhaust gas, it is necessary to operate with low efficiency so that the blades of the turbine are not worn or damaged. The dry electrostatic precipitator can completely prevent dust re-scattering, so the exhaust gas has a high cleanliness, and it has been cleaned both when used as industrial combustion gas and when recovering pressure. The exhaust gas can be used effectively.

  Furthermore, since the dry electrostatic precipitator according to the present invention can completely prevent dust re-scattering when the dust collecting electrode 1 is beaten, the dry electrostatic precipitator is different from the dry electrostatic precipitator according to the prior art. The device design for achieving the dust collection efficiency is easy. That is, in the dry electrostatic precipitator according to the prior art, since dust re-scatters, a higher dust collection capacity is required downstream of the gas flow, and a complicated device design corresponding to this is required. Since the dry electrostatic precipitator according to the present invention can completely prevent the dust from re-scattering, the dust collecting performance of each dust collecting container 8 can be made uniform. For example, when six dust collection containers 8 are arranged as shown in FIG. 1, when one of them collects dust, the remaining five units are responsible for dust collection. Therefore, the dust collection performance of 20% (= 100% / 5 units) may be given to each dust collection container. Similarly, when three dust collection containers 8 are arranged, 50% dust collection performance may be given to each dust collection container when two dust collection containers 8 are arranged.

  FIG. 5 is a schematic view showing an operation method of the dry electrostatic precipitator according to the present invention. As shown in FIG. 5, in the dry electrostatic precipitator according to the present invention, after the dust collection of any one of the dust collection containers 8 is finished, the dust collection container is shifted to dust collection, and the next dust collection container 8. It is desirable to repeat the operation of collecting the dust in sequence. As described above, the dry electrostatic precipitator according to the present invention can make the dust collecting performance of each dust collecting container uniform, so that stable operation of the entire apparatus is possible, and the dust collecting efficiency is improved. Can be improved.

Although the dry electrostatic precipitator according to the present invention shown in FIGS. 1 and 5 includes six dust collecting containers, the number of dust collecting containers 8 is not limited to this, and is required as the entire apparatus. Two or more units may be provided depending on the dust collection performance.
In the operation method illustrated in FIG. 5, first, the shielding means provided in the No1 container is closed to collect dust from the No1 container, and thereafter, the No2 container, the No3 container, and finally the No6 container arranged next to each other. This shows a cycle in which the shielding means provided in the container is closed and dust is collected from the container, and after the dust collection in the No6 container is completed, the dust is collected from the No1 container again. It is not limited to. Since the dust collection container 8 provided in the dry electrostatic precipitator according to the present invention can be each a closed system using shielding means for shielding the gas flow, the order in which dust is collected is arbitrarily set. be able to.

  Further, in the operation method illustrated in FIG. 5, dust collection is performed in all the dust collection containers 8 that do not block the shielding means, but is not necessarily limited thereto. Exhaust gas discharged from industrial furnaces such as heating furnaces, combustion furnaces, reduction furnaces, melting furnaces, drying furnaces, etc. When the dust collection performance required as a whole decreases, it is only necessary to operate dust collection containers that satisfy the reduced dust collection performance. For example, in the operation method illustrated in FIG. 5, when dust collection is performed with one dust collection container, the remaining five units are responsible for dust collection, but the exhaust gas flow rate is reduced to four units. When the dust collection performance of the minute is sufficient, the dust collection container 8 that satisfies the reduced dust collection performance may be operated.

It is a schematic diagram of the dry electric dust collector which concerns on this invention. It is side surface sectional drawing of the dust collecting container with which the dry electric dust collector which concerns on this invention is provided. FIG. 3 is a layout view of a discharge electrode and a dust collecting electrode, and is a cross-sectional view taken along line BB in FIG. 2. It is the top view seen from the A direction of FIG. It is a schematic diagram which shows the operating method of the dry-type electrostatic precipitator which concerns on this invention. It is a schematic diagram of the dry electric dust collector which concerns on a prior art, (A) is a plane sectional view, (B) is a side sectional view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Dust collection electrode 2 Discharge electrode 3 High voltage DC power source 4 Head insulator chamber 5 Support insulator chamber 6 Inlet dust collection main pipe 7 Inlet pipe 8 Dust collection container 9 Hopper 10 Rectifier 11 Exit pipe 12 Damper 13 Outlet cleaning main pipe 14 Gas flow 15 Gas detour 16 Mobile curtain 17 Mechanical hammer

Claims (2)

An inlet pipe for introducing exhaust gas into the container;
A discharge electrode provided inside the container for charging the dust in the exhaust gas;
A dust collecting electrode provided inside the container for collecting charged dust;
A hopper provided at the bottom of the container for collecting dust dropped from the dust collection electrode;
An outlet pipe for discharging the exhaust gas purified inside the container to the outside of the container;
Shielding means for shielding the gas flow introduced into the container and the gas flow led out of the container;
A plurality of dust collection containers are provided,
The inlet pipes of each dust collection container are connected to each other,
A dry electrostatic precipitator in which the outlet pipes of each dust collecting container are connected to each other.
An inlet pipe for introducing exhaust gas into the container;
A discharge electrode provided inside the container for charging the dust in the exhaust gas;
A dust collecting electrode provided inside the container for collecting charged dust;
A hopper provided at the bottom of the container for collecting dust dropped from the dust collection electrode;
An outlet pipe for discharging the exhaust gas purified inside the container to the outside of the container;
Shielding means for shielding the gas flow introduced into the container and the gas flow led out of the container;
A plurality of dust collection containers are provided,
The inlet pipes of each dust collection container are connected to each other,
A method of operating a dry electrostatic precipitator in which outlet pipes provided in each dust collecting container are connected to each other,
The dust collection container shielding means of any of the plurality of dust collection containers is closed and the gas flow introduced into the dust collection container and the gas flow led out of the dust collection container are stopped. The dust collecting electrode provided in the dust container is beaten to drop the dust collected by the dust collecting electrode, and the shielding means that has been closed after the elapse of a predetermined time is opened, and a plurality of dust collecting devices are arranged. The operation method of the dry electrostatic precipitator which repeats sequentially about a container.

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