JPH0153084B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a dust collection and incineration method for collecting and incinerating fine carbon particles contained in exhaust gas and the like. Diesel engine exhaust gas contains gas-phase deposited carbon particles, and most of these particles are
It is microscopic, less than 1μ. 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 2 ₁ and 2 ₂ formed between a large number of porous thin walls 1, and the outlet side of the gas channels 2 ₁ is sealed with ceramic plugs. 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 2 ₁ whose outlet side is sealed is not sealed at its inlet side, and the gas flow path 2 ₂ whose inlet side is sealed is not sealed at its outlet side, so that the exhaust gas A is ₁ through the porous thin wall 1 and into the gas flow path 2 ₂ . This ceramic filter collects and purifies the exhaust gas A when it passes through the porous thin wall 1, but since it is a mechanical purification method, it quickly becomes clogged, resulting in extremely high pressure loss. For this reason, there is a problem that it cannot withstand long-term use. The present invention was made in view of the above circumstances, and
The purpose is to apply voltage to improve the dust collection rate and reduce the rate of increase in pressure drop.
Furthermore, the present invention aims to provide a dust collection and incineration method that can be operated continuously for a long period of time by incinerating and gasifying carbon particles using electric discharge when dust is accumulated. That is, in the present invention, an electrode made of a thin metal wire is arranged in a gas flow path on the gas inflow side, sandwiching an insulating porous filter that allows dust-containing gas to pass through and collect dust.
An electrode is placed in the gas flow path on the gas outlet side, and a DC or AC voltage is applied between the electrodes during dust collection to collect dust, and an AC or AC pulse voltage is applied between the electrodes during dust incineration. The method is characterized in that the collected dust is incinerated. The present invention will be described below with reference to illustrative embodiments. FIG. 3 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 and electrodes 12 and 13. This filter 11 has a structure similar to that shown in FIGS. 1 and 2, and has a large number of porous thin walls 14.
Gas flow paths 15 ₁ and 15 ₂ are formed between the gas flow paths 15 ₁ and 15 ₂ , and ceramic plugging materials 16 and 17 are provided on the outlet and inlet sides of the gas flow paths 15 1 and 15 2 , so that exhaust gas A can flow from the gas flow path 15 ₁ . Gas flow path 1 through porous thin wall 14
5 It is starting to flow into ₂ . Examples of the structures include those shown in Table 1 below.

[Table] The symbols D and L in the above table indicate 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 of a thin metal wire made of a material such as W, Au, or Pt and has a wire diameter of 50 to 1000 μm, and is inserted into the gas flow path 15 ₁ on the gas inflow side, that is, on the dust collection side. The electrode 13 is made of a fine metal wire of the same material and size as the electrode 12, and is inserted into the gas flow path ₁₅₂ on the gas outlet side. Therefore, the electrodes 15 ₁ and 15 ₂ face each other with the porous thin wall 14 in between. In this case, the electrodes 12 and 13 do not all need to be placed in the gas flow paths 15 ₁ and 15 ₂ , and may be inserted every other electrode or every other electrode.
Further, the electrode 13' disposed 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 disposed along the porous thin wall 14, as shown in FIG. good. 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 pulsed voltage thereof, and is set to a relatively low voltage that does not heat and oxidize the carbon particles. By applying a voltage, fine carbon particles are aggregated and coarsened mainly due to the action of alternating current, and a deposited dust layer with a high porosity is formed mainly due to 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 accumulates, the electrode 12,
An alternating current or alternating pulse voltage is applied between 13 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, and are gasified. Note that the application of high voltage for dust incineration is preferably performed in synchronization with the gas temperature rising to 600 to 700° C. or higher. As explained above, according to the method of the present invention, the particles are aggregated and coarsened to improve the dust collection rate, and the porosity of the deposited particle layer is increased to prevent pressure loss from increasing, and the dust is further deposited. However, when the pressure drop increases, the carbon particles are incinerated using electrical discharge.
Because it is gasified, it has the remarkable effect of preventing clogging and allowing continuous operation for long periods of time.

[Brief explanation of drawings]

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. FIG. 4 is an explanatory diagram showing the symbols t, p, and h in the structural characteristics of Table 1, and FIG. 5 is a structural model diagram of a dust collection and incineration apparatus showing another embodiment of the present invention. 11... Insulating porous filter, 12, 13...
Electrode, 14... Porous thin wall, 15 ₁ , 15 ₂ ... Gas flow path, 16, 17... Ceramic sealing material.

Claims (1)

[Claims] 1. Place an electrode made of thin metal wire in the gas flow path on the gas inflow side between the insulated porous filters that collect dust by passing the dust-containing gas, and place an electrode in the gas flow path on the gas outflow side to collect the dust. At times, a DC or AC voltage is applied between the electrodes to collect the dust, and at the time of dust incineration, an AC or AC pulse voltage is applied between the electrodes to incinerate the collected dust. Dust collection and incineration method.