JPH01164460A - Dust collector with electrically charged particle packing layer - Google Patents

Abstract

PURPOSE:To stably collect dust even small particles of soot with low electric resistance by flowing the gas contg. dust from lower part to upper part through the electrically charged particle packing layer dust collector in which newly charged particles are supplied from the upper part and polluted particles are discharged from the lower part. CONSTITUTION:The packing material 2 is supplied into a dust collecting vessel 1 from a supply system 3 and a discharge electrode 8 is charged with high voltage to impress voltage to the packing material 2 existing between the discharge electrode 8 and the confronting electrode, that is, the dust collecting vessel 1. On the other hand, the gas contg. dust is flowed from a dust contg. gas introducing opening 5 through the space between the electrodes 1, 8 and, at the same time, new packing material 2 is supplied from the upper part to collect dust. The polluted packing material 2 is discharged through a discharge system 4 and the gas deprived of dust is discharged from a gas discharge opening 6 in the upper part. As a result, the gas of low dust concn. is deprived of dust in the upper part and the gas of high dust concn. is deprived of dust in the lower part with the result that the utilizing efficiency of packing material and the dust collecting efficiency are raised.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electrostatic precipitator. More specifically, the present invention relates to a charged particle packed bed dust collector in which charged particles are filled between discharge electrodes to combine electrostatic dust collection and filtration dust collection.

(Prior Art) As shown in FIG. 7, in a conventional charged particle packed bed dust collector, a dust-containing gas is introduced into a dust collection container 101 filled with charged particles 103 so as to cross the container 101. There is a cross-flow type that collects dust. This dust collector collects dust by flowing a dust-containing gas in a direction perpendicular to the moving direction of charged particles 103 filling a dust collection container 101, and discharge electrodes 102 are installed from the top to the bottom of the dust collection container. Along with this j & Ijl container 1
The charged particles 103 are moved from above to below 01. Note that the reference numeral 104 is a power source.

(Problem to be solved by the invention) However, according to this orthogonal charged particle packed bed precipitator, when collecting low electrical resistance dust (such as heavy hydraulic pressure or coal gasification char), it is difficult to A leakage current begins to flow through the dust 171 deposited on the surface of the particles 103, the applied voltage decreases, and the dust collection effect by the electric field disappears. This is I! In order to achieve this, it is necessary to make the movement speed extremely fast, but as the gas flow rate increases, the collected soot and dust will be re-entrained (hydrodynamic re-entrainment phenomenon).
The drawback is that the dust collection efficiency is extremely low. Furthermore, regarding the charged particles that are discharged, that is, the filler 103, while a large amount of soot and dust is collected on the gas inlet side, almost no soot and dust is collected on the gas discharge side, and the filler is wasted. occurs. As such, conventional charged particle packed bed precipitators have the disadvantage that they are not suitable for use with soot and dust having low electrical resistance.

SUMMARY OF THE INVENTION An object of the present invention is to provide a charged particle packed bed dust collector that can continuously and stably collect particulate matter having low electrical resistance with high dust collection efficiency.

(Means for Solving the Problems) In order to achieve the above object, the charged particle packed bed precipitator of the present invention includes insulating particles having a high dielectric constant between the discharge electrode and its counter electrode in the dust collection container. A dust-containing gas is introduced between the electrodes from the lower part, and new filled particles are supplied from the upper part to collect the dust. The filled particles contaminated by the dust collection are discharged from the lower part, while the dust is removed from the L part. The remaining gas is expelled.

Further, the charged particle packed bed precipitator of the present invention is characterized by having a structure in which the length of the discharge electrode is shortened and no voltage is applied to the contaminated packed particles after collecting soot and dust at the bottom of the packed bed.

(Function) Therefore, the newly supplied filling material in the upper part collects the gas with a low dust load that has already been collected in the lower part, and also the filling material in the lower part which has already been collected for a long time and is dirty. Collects scum with a high dust load at the dust collector inlet. For this reason, the dust load in the packed bed is extremely high at the bottom as shown in Figure 2 (B), and the leakage current increase area due to the adhesion of low electrical resistance dust to the filler is as shown in Figure 2 (A). smaller than the standard dust collector.

In addition, when a short electrode is used, the precipitator becomes a precipitator that integrates a particle packed bed precipitator as a pre-dust collector and a charged particle packed bed precipitator as a precision dust collector.

(Example) Hereinafter, the configuration of the present invention will be described in detail based on an example shown in the drawings.

FIG. 1 shows an embodiment of the charged particle packed bed dust collector of the present invention. In this example, in order to conduct basic experiments such as the dust collection effect, a device for producing dust-containing gas and a measuring instrument were installed in the dust collection container 1.
However, it goes without saying that these devices are not essential to the present invention.

This dust collector includes a cylindrical dust collection container 1 filled with charged particles 2 and charged with a high voltage, and charged particles (hereinafter also referred to as filler) 2 as a filler from the upstream side of the dust collection container 1. a filler supply system 3 that supplies the filler 2, a filler discharge system 4 that discharges the filler 2 on the downstream side of the dust collector main body 1, a discharge electrode 8 installed in the dust collection container 1, and its ancillary equipment. The filling material 2 is made to flow down from above and discharged from below, while the dust-containing gas is introduced from below and taken out from the upstream side, so that the filling material 2 and the dust-containing gas are brought into self-flow contact. ing.

The dust collecting container 1 is grounded and is provided so as to constitute a counter electrode for the discharge l#18 in the center thereof. Therefore, the filling material 2 flowing down inside the dust collecting container 1 moves while filling the gap between the discharge electrode and its counter electrode. Further, the dust-containing scum inlet 6 of this dust collecting container 1 is provided at the lower part, and the gas outlet 5 is provided at the upper part.

The dust-containing gas is moved in a direction opposite to the moving direction of the filler 2, and is provided so as to come into countercurrent contact with all of the filler 2. Moreover, means for supplying and discharging the filler and controlling the amount thereof, such as roll feeders 9 and 10, are provided at the upper and lower parts of the dust collecting container 1. Therefore, the moving speed of the filler 2 can be adjusted by controlling the feeder of the filler supply system 3 and the feeder 10 of the discharge system 4, respectively. Further, the dust-containing gas inlet 5 of the above-mentioned dust collector is equipped with a dehumidifier 51, an absolute filter 52, a char supply device 53, an ejector 54, and a dust concentration measuring device in order to artificially generate and supply dust-containing gas. 55
and a temperature measuring device 56 are connected. Further, a temperature measuring device 61, a soot/dust concentration measuring device 62, an absolute filter 63, a suction fan 64, and a gas meter 65 are connected to the gas outlet 6 in this order.

Further, as the charged particles 2 serving as the filler, insulating particles with a high dielectric constant, such as mullite particles, focused particles, 10Ill
IIφ mullite particles are used.

In the figure, numeral 7 is a high-voltage charge source, and 8 is a discharge electrode. In the case of this embodiment, the discharge electrode 8 is a short electrode that does not reach the lowest part of the dust collection container 1, and the structure is such that no voltage is applied to the contaminated filling material 2 after dust collection at the bottom of the filling bed. There is. That is, the discharge electrode length may be such that it does not charge the leakage current increasing region shown in FIG. 2(B). For this reason, in the case of the device of the present invention, where the leakage current increase area is smaller than that of conventional precipitators and is located in the lower layer, it is possible to apply voltage to most parts of the packed bed, even though it is a short electrode. Since the entire amount of processing gas passes through the charged packed layer, high dust collection efficiency can be expected even with a short electrode.

According to the charged particle packed bed precipitator configured as described above, dust collection is performed in the following manner.

First, the filling material 2 is supplied from the supply system 3 into the dust collecting container 1, and a high voltage is applied to the discharge electrode 8 to place the filling material 2 between the discharge electrode 8 and the dust collecting container 1, which is the opposite electrode. Apply voltage to. On the other hand, a dust-containing gas is introduced between the electrodes 1 and 8 from a dust-containing gas inlet 5 at the bottom of the dust collection container 1, and new filling particles 2 are supplied from the top to generate S dust. Then, while the contaminated packed particles 2 are discharged from the lower discharge system 4, the gas after dust removal is discharged from the upper gas discharge port 6.

At this time, the moving speed of the filler 2 is determined by the soot and dust load in the process gas, and when the soot and dust load is high due to high soot and dust concentration or high flow rate, the movement speed is increased, and conversely, when the soot and dust load is low, the movement speed is increased. By lowering the moving speed, stable operation with high dust collection efficiency can be achieved. For example, the inlet dust concentration is 3Q7m3, the dust collection flow rate is 21
When collecting dust at cm/SeC, the moving speed is preferably 1.33 m/hr or more. As is clear from Figure 3, which shows the time-dependent change in the applied voltage in this case, and Figure 4, which shows the time-dependent change in the discharge current, in fixed bed operation, that is, when the charged particles 2 are not moved, the discharge current changes after approximately 30 seconds. begins to increase, and after 1 minute, the applied voltage begins to decrease. And about 2
After a few minutes, voltage application becomes impossible due to an extreme increase in leakage current. However, when the moving speed of the self-flowing moving bed type of the present invention is increased, the applicable time is extended, and the moving speed is 1.3.
Continuous operation is possible at 3 m/llr or more, and stable charging can be performed at all times. Furthermore, Figure 5 shows the measurement results of the filler movement speed that enabled continuous operation when a similar experiment was conducted while changing the char concentration and filtration rate. This will help you understand that continuous operation is always possible.

(Effects of the Invention) As is clear from the above explanation, the charged particle packed bed precipitator of the present invention fills insulating particles with a high dielectric constant between the discharge electrode and its counter electrode in the dust collection container. , a dust-containing gas is introduced from the bottom between the electrodes, and new filling particles are supplied from the top. The packed particles contaminated by dust collection are discharged from the lower part, while the gas after dust removal is discharged from the upper part, so the newly supplied filling material in the upper part has already been collected in the lower part. The gas with a low dust load after being dusted is collected, and the filling material at the bottom, which has already been contaminated for a long time, collects the gas with a high dust load at the entrance of the dust collector. For this reason, the dust load in the packed bed is extremely high at the bottom as shown in Figure 2 (B), and it is likely that the leakage current increases due to the adhesion of low electrical resistance dust to the filler, as shown in Figure 2 <A). smaller than the standard dust collector.

Therefore, according to the present invention, a charged particle packed bed precipitator with high dust collection performance can be used for dust with low electrical resistance, so it can handle dust with a wide range of properties from conductive dust to dust with high electrical resistance. It has high dust collection efficiency for the objects to be collected, low pressure loss, and efficient use of the filler material, which has great practical effects. For example, according to the experimental results shown in Figure 6, which compares the dust collection performance of the charged particle-filled dust collector of the present invention with that of the uncharged state (filtration current collection), it is found that the particle size is about 1 μm, which makes it difficult to collect dust. The dust collection rate is 50 in the uncharged state for particles of
Compared to the conventional charged particle packed bed precipitator, this method can reduce the charged particle concentration to about 98%, and the outlet concentration can be reduced to about one-twentieth. Since the flow of leakage current on the particle surface is small, the movement speed is small and re-scattering can be prevented.

[Brief explanation of the drawing]

Figure 1 is a principle diagram showing one embodiment of the charged particle packed bed precipitator of the present invention installed as a basic experimental device, and Figure 2 (
A>, (B) are graphs showing the relationship between the dust load and electrical resistance distribution in the layers of the conventional charged particle packed bed precipitator and the charged particle packed bed precipitator of the present invention, FIGS. 3 to 6 The figure is a graph showing the experimental results of the present invention. Figure 3 is the change in applied voltage over time with the moving speed as a parameter, Figure 4 is the change in discharge current over time with the moving speed as a parameter, and Figure 5 is the char concentration. Figure 6 shows the relationship between the filtration speed and the moving speed of the filler that enables continuous operation using the parameter . This is compared to the side. FIG. 7 is a schematic structural diagram showing an example of a conventional charged particle-filled dust collector. 1... Dust collection container (counter electrode), 2... Filler (charged particles), 3... Filler supply system, 4... Filler discharge system, 5...
- Dust-containing gas inlet, 6... Gas outlet, 7... High voltage charging power source, 8... Electrode, 9.10... Means for controlling the moving speed of charged particles (feeder). Patent applicant Central Research Institute of Electric Power Industry Figure 2 (A) (B) Figure 7

Claims (2)

[Claims] (1) Insulating particles with a high dielectric constant are filled between a discharge electrode and its counter electrode in a dust collection container, and a dust-containing gas is introduced from the bottom between the electrodes, and new filling particles are supplied from the top. A charged particle packed bed dust collector is characterized in that the charged particle packed bed dust collector collects dust and discharges the contaminated packed particles from the lower part, while the gas after dust removal is discharged from the upper part. (2) The charged electric charge according to claim 1, characterized in that the length of the discharge electrode is shortened, and a structure is adopted in which no voltage is applied to the contaminated packed particles after collecting soot and dust at the bottom of the packed bed. Particle packed bed dust collector.