JPS59127621A - Dust collecting and burning method - Google Patents

Abstract

PURPOSE:To enable longtime continuous operation, by applying voltage between electrodes each comprising a metal wire arranged in a gas inflow passage to enhance dust collecting efficiency while burning and gasifying carbon particles by utilizing electric discharge when dust is accumulated. CONSTITUTION:Exhaust gas A containing fine carbon particles is flowed to mechanically collect fine carbon particles by a porous thin wall 14. In performing this dust collection, voltage is applied between electrodes 12, 13. By the application of voltage, fine carbon particles are flocculated and grown into coarse particles mainly by AC action and an accumulated dust layer having a large void ratio is formed mainly by DC action. When dust is accmulated to a certain degree, AC or AC pulse voltage is applied between the electrodes 12, 13 to generate streamer discharge and carbon particles are oxidized and burnt by this discharge to gasify the same. In this case, the application of high voltage for burning dust is pref. performed in synchronous relation to the rising in a gas temp. when said gas temp. reaches 600-700 deg.C or more.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dust collection and incineration system that collects and incinerates fine casene particles contained in exhaust gas and the like.

Diesel engine exhaust gas and the like contain vapor-phase deposited carbon particles, and most of these particles are as fine as 1 μm or less. For this reason, a ceramic filter having fine pores is used as a dust collector for exhaust gas. As shown in FIGS. 1 and 2, this ceramic filter has gas channels 21 and 22 formed between a large number of porous thin walls 1, and the outlet side of the gas channels 21 is covered with a ceramic sealing material 3. At the same time, the inlet side of the gas flow path 22 is sealed with a ceramic sealing material 4. In this case, the gas flow path 21 whose outlet side is sealed is not sealed at its inlet side, and the gas flow path 2□ which is sealed at its inlet side is not sealed at its outlet side, so that the exhaust gas A is From the channel 21 through the porous thin wall 1 to the gas flow channel 2
2.

In this ceramic filter, the exhaust gas A is made of porous thin wall 1
Dust is collected and purified when passing through the pipe, but since this is a mechanical purification method, clogging occurs easily, resulting in extremely high pressure loss. There is a problem with this product that it cannot withstand long-term use.

The present invention has been made in view of the above circumstances, and its purpose is to improve the dust collection rate by applying voltage, reduce the rate of increase in pressure drop, and also prevent discharge when dust accumulates. By incinerating and gasifying carbon particles using the present invention, the object is to obtain a simple dust collection and incineration method that can be operated continuously for a long period of time.

That is, in the present invention, an electrode made of a thin metal wire is placed in the gas flow path on the gas inflow side, sandwiching an insulated porous filter that allows dust-containing gas to pass through and collect the dust, and an electrode is placed in the gas flow path on the gas outflow side. Then, when dust is collected, a DC or AC voltage is applied between the electrodes to collect the dust, and when the dust is incinerated, an AC or AC pulse voltage is applied between the electrodes to incinerate the collected dust. It is characterized by

The present invention will be described below with reference to illustrative embodiments. Third
The figure is a schematic sectional view of a dust collection and incineration device used in the method of the present invention. This device includes an insulating porous filter 11,
It is equipped with electrodes 12 and 13. This filter 11 is
With a structure similar to that shown in FIGS. 1 and 2, a gas flow path 151r15Z is formed between a large number of porous thin walls 14, and ceramic self-sealing is provided on the outlet and inlet sides of the gas flow path 151 * 152. Materials 16 and 17 are provided, and the exhaust gas A flows through the gas flow path 15! The gas flow path 15 passes through the porous thin wall 14 from
2. Examples of the structures include those shown in Table 1 below.

Table 1 (Filter Structural Characteristics) In the above table, the symbol L indicates the diameter and length of the filter shown in FIG. 2, and the symbols t, p, and h are shown in FIG. 4.

On the other hand, the electrode 12 is made from a fine metal wire with a wire diameter of 50 to 1000 μ made of materials such as W′ r Au r P and D.
, is inserted into the gas flow path 151 on the gas inflow side, that is, on the dust collection side. The electrode 13 is made of the same material and has the same dimensions as the electrode 12, and is inserted into the gas flow path 152 on the gas outlet side. Therefore, the electrode 151
．． 152 are opposed to each other with the porous thin wall 14 interposed therebetween. In this case, the electrodes 12.13 do not all need to be arranged in the gas flow path '5x+152, but may be inserted every other electrode or every other electrode. Further, the electrode 13' arranged in the gas flow path 152 on the gas outlet side is not limited to a thin metal wire, but may also be one in which a porous conductor is arranged along the porous thin wall 14, as shown in FIG. −.

Thus, in the method of the present invention, the exhaust gas A containing fine carbon particles is passed through and the fine carbon particles are mechanically collected by the porous thin wall 14. During this collection, a voltage is applied between the electrodes 12 and 13.

In this case, the applied voltage is a direct current, an alternating current, or a pulse voltage thereof, and is set to a relatively low voltage that does not cause the carbon particles to become heated and oxidized. By applying a voltage, fine carbon particles are aggregated and coarsened mainly by the action of alternating current, and a deposited dust layer with a thick porosity is formed mainly by the action of direct current. Therefore, since the porosity is large, an increase in pressure drop is prevented, and the particles are aggregated and coarsened, so that the dust collection rate is improved.

Next, when a certain amount of dust has accumulated, an alternating current or alternating pulse voltage is applied between the electrodes 12 and 13.

In this case, the applied voltage is set to a high voltage to generate a streamer discharge, and the carbon particles are oxidized and burned by this discharge, thereby gassing them.

In addition, when applying high voltage to the dust incineration tank, the gas temperature is 6.
It is preferable to carry out the process in synchronization with the temperature when the temperature rises to 00 to 700°C or higher.

As explained above, according to the method of the present invention, particles can be aggregated,
In addition to increasing the porosity of the deposited particle layer to improve the dust collection rate, when dust accumulates and the pressure drop increases, the carbon particles are removed using electrical discharge. It has the remarkable effect of preventing incineration, gasification, and clogging, allowing continuous operation for long periods of time.

[Brief explanation of the drawing]

FIG. 1 is a front view showing a structural model of a conventionally used ceramic filter, FIG. 2 is a cross-sectional view of the same, and FIG. 3 is a structural model diagram of a dust collection and incineration device showing an embodiment of the present invention. Figure 4 shows symbols t, p, and structural characteristics in Table 1.
FIG. 5 is a structural model diagram of a dust collection and incineration device showing another embodiment of the present invention. 11... Insulating porous filter, 12.13... Electrode, 14... Porous thin wall, 151. ．． 152... Gas flow path, 16.17... Ceramic mouth sealing material. Applicant Sub-Agent Patent Attorney Takehiko Suzue Figure 1
Figure 2-■ Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] An electrode made of thin metal wire is placed in the gas flow path on the gas inflow side between an insulated porous filter that collects dust by passing through it, and an electrode is placed in the gas flow path on the gas outflow side. The dust is collected by applying a DC or AC voltage between the electrodes, and the collected dust is incinerated by applying an AC or AC i9 voltage between the electrodes when incinerating the dust. Dust collection and incineration method.