JPH09323050A - Dry type electrostatic precipitator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deposition of dust by arranging a gas jetting nozzle at a dust deposition position of a hopper for collecting the dust by a dust collection electrode at the lower part and jetting gas from the nozzle toward the dust collection position. SOLUTION: Process gas enters the inside of a casing 2 from the inlet. Since a discharge electrode electrifies powder particles in the process gas, the powder particles stick to the dust collection electrode and are separated from the process gas. The separated powder particles drop naturally or drop with a hammering work of a hammer machine, being collected in the hopper 5 as the dust 7, loaded on a conveyer and discharged from a dust discharge port. The nozzles 11, 12 periodically jet the gas 18 to a joint part of the hopper 5 or a corner part, and the dust 7 deposited on these parts are forcedly fallen down with a jetting stream. Thus, deposition and sticking of the dust 7 are prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry type electrostatic precipitator for collecting powder particles as dust from process gas, and more particularly to means for preventing dust accumulation in a hopper portion.

[0002]

2. Description of the Related Art A dry type electrostatic precipitator is used as a facility for collecting powder particles in process gas as dust in a facility for drying powder. Generally, this dry type electrostatic precipitator has a plurality of electric wire-shaped discharge electrodes inside the casing, and flat plate-shaped dust collecting electrodes arranged in parallel so as to sandwich the electric discharge electrodes, and the lower part of the casing. Then, it has a lower hopper for collecting the dust falling from the dust collecting electrode and a conveyor for discharging the dust collected by the hopper.

In the dry electrostatic precipitator, a negative high voltage is applied to the discharge electrode and a positive voltage is applied to the dust collecting electrode to pass the process gas through the casing.
The powder particles charged by the corona discharge of the discharge electrode are adsorbed and captured by the dust collecting electrode by the Coulomb force to collect the dust. The powder particles separated from the process gas by the dust collecting electrode fall as dust naturally or by a hammering mechanism, are collected by a lower hopper, and are discharged by a discharging conveyor.

In order to quickly drop the collected powder particles from the dust collecting electrodes and discharge them, and to drop and discharge the powder particles attached to the discharge electrode, the inner surface of the hopper, etc., those electrodes are hammered. A hammer is installed. However, due to the structure of the horse-backed (roof-shaped) mating portion between the hopper and the hopper and the corner portion of the hopper, there is a problem that vibration of the hammering machine is difficult to be transmitted and powder particles are easily deposited. Furthermore, if powder particles accumulate on the hopper's mating parts or corners, the accumulated powder particles will contact the lower end of the discharge electrode and become grounded, making it impossible to apply a voltage. There was also the problem that it would not be possible to collect dust.

Conventionally, in order to prevent the above-described accumulation phenomenon, it is usually necessary to remove the dust accumulated in the hopper every two or three months. In addition, when dust cannot be collected in the above condition, the operation of the electrostatic precipitator must be stopped and the dust accumulated by the worker must be removed manually. It was work of, and the measures were desired.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a dry type electrostatic precipitator that can be operated in a stable state without causing the inability to collect dust due to dust accumulation.

[0007]

In order to solve the above-mentioned problems, the present invention is a dry type electrostatic precipitator in which a gas injection nozzle is arranged at a dust accumulation position of a lower hopper for collecting dust of a dust collecting electrode. By injecting gas from this nozzle toward the dust accumulation position, dust accumulation is prevented.

[0008]

1 and 2 show a dry type electrostatic precipitator 1 of the present invention. The dry electrostatic precipitator 1 is intended to remove exhaust gas for drying in a facility for drying powdered copper ore, which is a smelting raw material of copper, for example, and has a discharge electrode 3 formed by a plurality of electric wires inside a casing 2. , Having flat plate-shaped dust collecting electrodes 4 arranged in parallel so as to sandwich these discharge electrodes 3, and at the lower part of the casing 2, a hopper 5 for collecting dust 7 and a dust 7 collected by the hopper 5. Is provided with a conveyor 6 for discharging.

The casing 2 is a hollow rectangular parallelepiped as a whole, and forms an inlet 8 for the process gas 17 at one end and an outlet 9 at the other end, and is divided into two rows along the flow direction of the process gas 17. Moreover, since it is divided into four in the direction orthogonal to the flow direction, the inside thereof is spatially divided into eight with no partition.

The discharge electrode 3 and the dust collecting electrode 4 are
The dust collecting electrodes 4 are arranged collectively in each of eight divided sections, and are in a state parallel to the flow direction of the process gas 17. The dust collecting electrode 4 is provided with a hammer 16 for removing the dust 7.

The hopper 5 has, for example, an inverted quadrangular pyramid shape,
It is provided in the lower part of the casing 2 for every two sections divided into two rows along the flow direction of the process gas 17. Therefore, the connecting portion of the hoppers 5 has the shape of a horse's back (roof) and forms an upwardly inclined surface.
The conveyer 6 is, for example, a flow conveyer or a screw conveyer, and moves the upper conveying surface below the discharge port of the hopper 5 inside the casing 2 toward the dust discharge port 10.

The dry electrostatic precipitator 1 of the present invention is provided with a plurality of injection nozzles 11 and 12 as a characteristic configuration, as shown in FIGS. These nozzles 11 and 12 are, for example, the most upstream side, that is, the inlet 8
It is arranged at the dust accumulation position of the hopper 5 on the side, that is, at the corner portion and / or the joining portion of the adjacent hoppers 5, and is directed in the direction of blowing away the dust 7 accumulated at that position.

That is, the jet-shaped nozzles 11 are arranged in a zigzag shape along the joint portion,
Each of them is provided so as to face the apex of the joining portion and be inclined in the flow direction of the process gas 17. Further, the tubular nozzle 12 is configured by a pipe having a plurality of nozzle holes, and is provided inside the left and right hoppers 5 in parallel with each other along the upstream corner portion (surface joining line). . These nozzles 11 and 12 are guided from the inside of the hopper 5 to the outside by a pipe 13,
It is connected to a pressure gas source 15 via an on-off valve 14.

During operation of the dry electrostatic precipitator 1, process gas 1
7 enters the inside of the casing 2 through the inlet 8. here,
The discharge electrode 3 charges the powder particles in the process gas 17, so that the powder particles adhere to the dust collecting electrode 4 and the process gas 1
Separate from 7. The separated powder particles are naturally dropped or dropped by the hammering action of the hammering machine 16, and the hopper 5
Is collected as dust 7 inside, is carried on the conveyor 6, and is discharged from the dust discharge port 10.

The mating portion of the hopper 5 and the corner portion of the hopper 5 are structurally hard to transmit the vibration of the hammering machine 16, and are positions where powder particles are easily deposited. In particular, since the upstream hopper 5 has the highest dust collecting effect, the mating portion and the corner portion of the hopper 5 near it are places where the powder particles are more likely to be deposited than other portions. .

Therefore, the nozzles 11 and 12 periodically inject, for example, the gas 18 to the joining portion or the corner portion of the hopper 5, and the dust 7 accumulated on the portion is forcibly dropped by the jet flow of the gas 18. Let Gas for injection 18
Is nitrogen, air, steam, or the process gas 17 after dust removal by the dry type electrostatic precipitator 1. This is because the dust collecting effect of the dry type electrostatic precipitator 1 is not deteriorated, and the harmful gas that causes pollution is not discharged. The injection amount, speed, and injection frequency of the gas 18 may be determined according to the scale of the equipment and the deposition status of the dust 7, and are not particularly limited.

The inventor utilizes the dry type electrostatic precipitator 1 having the above-mentioned configuration and uses nitrogen gas as the gas 18 for injection,
1. At a speed of 150 [m / sec] from the nozzles 11 and 12, 2.
Injection was performed intermittently every 5 [seconds] every 5 [minutes].
As a result, over 2 [years] or more, the accumulation of dust 7 on the corner portion and the joining portion of the hopper 5 was completely eliminated, and the effect was remarkable.

When the injection operation is performed only before and after the operation of the dry electrostatic precipitator 1, the on-off valve 14 may be of a manual type. However, when the injection operation is periodically performed during the operation of the dry electrostatic precipitator 1, the opening / closing valve 14 is electrically operated, and its control is automatically performed by a timer control device or the like.

[0019]

As described above, according to the dry electrostatic precipitator of the present invention, the nozzle is provided inside the hopper at a position where dust is likely to be accumulated, and the gas is jetted from the nozzle, whereby the dust is discharged. Since it is possible to prevent the accumulation and adherence of dust, it is possible to continue stable operation without causing dust collection failure due to the accumulation of dust (powder particles).

[Brief description of drawings]

FIG. 1 is a schematic plan view of a dry electrostatic precipitator of the present invention.

FIG. 2 is a schematic sectional view of the dry electrostatic precipitator of the present invention.

FIG. 3 is a plan view of a hopper and a nozzle portion.

FIG. 4 is a cross-sectional view of a hopper and a nozzle portion viewed from a side surface.

FIG. 5 is a cross-sectional view of a hopper and a nozzle portion as viewed from the front.

[Explanation of symbols]

 1 Dry Electrostatic Precipitator 2 Casing 3 Discharge Electrode 4 Dust Collection Electrode 5 Hopper 6 Discharge Conveyor 7 Dust 8 Inlet 9 Outlet 10 Dust Discharge Port 11 Nozzle 12 Nozzle 13 Piping 14 Open / Close Valve 15 Pressure Gas Source 16 Hammer 17 Process Gas 18 gas

Claims (1)

[Claims] 1. A nozzle for injecting a gas is arranged at a dust accumulation position of a lower hopper for collecting dust of a dust collecting electrode,
A dry type electrostatic precipitator characterized by preventing dust accumulation by injecting gas from this nozzle toward the dust accumulation position.