JP2004216201A - Method and apparatus for removing black smoke of combustion exhaust gas, incomplete combustion product and nox - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for economically removing black smoke or/and incomplete combustion products generated by combustion of carbon-based fuel or NOx when the exhaust gas further contains NOx in high efficiency, and an apparatus capable of applying the removal method and for removing the black smoke or/and incomplete combustion products generated by combustion of the carbon-based fuel or NOx when the exhaust gas further contains NOx. <P>SOLUTION: The exhaust gas generated by the combustion of the carbon-based fuel is brought into contact with the pulsative corona discharge generated along the surface of a dielectric by impressing pulsative voltage between metallic electrodes arranged on the surface of the dielectric so as to remove the black smoke or/and incomplete combustion products in the exhaust gas or NOx when the exhaust gas further contains NOx. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to black smoke (particulate matter contained in exhaust gas of diesel engine, main constituents: carbon and hydrocarbon), which is an environmentally harmful chemical substance generated by combustion of carbon-based fuel, gaseous or liquid imperfections combustion product (hereinafter, incomplete combustion products and abbreviation), method of removing such NO _X, in particular mobile combustion device, for example an automobile, motorcycle, ship, and the black smoke discharged from the aircraft or the like, incomplete combustion products, NO _{The present} invention relates to an effective and economical processing method for _{X and the} like. More particularly, a hazardous chemical substance for the human body and / or the global environment, the black smoke generated by combustion of carbonaceous fuel, incomplete combustion products, the NO _X etc., pulsed corona surface discharge in response to these emissions TECHNICAL FIELD The present invention relates to a processing method and a processing apparatus for detoxification using technology.
[0002]
[Prior art]
Gases emitted by the combustion of carbon-based fuels such as gasoline fuel, diesel light oil fuel, and LPG fuel mainly contain air pollutants such as nitrogen oxides (NOx) such as nitric oxide and nitrogen dioxide, and particulate matter. In. In particular, from diesel engine vehicles using diesel fuel, the amount of nitrogen oxides is about three times as large as that emitted from gasoline vehicles using gasoline fuel. Particulate matter having a diameter of 2.5 μm or less is discharged, causing health problems such as respiratory diseases and asthma, and has become a social problem. However, although emission regulations have been set for nitrogen oxides and measures have been taken, measures for particulate matter have not yet been implemented, such as the absence of any emission regulations for most diesel engine vehicles. Remains enough. In particular, the environmental standard as a basis for controlling particulate matter contained in diesel engine exhaust gas is also referred to as “PM2.5 environmental standard”, and legislation is an important issue. Particulate matter includes not only primary particles but also secondary particles such as black smoke or soot (black amorphous carbon particles), road dust, sulfur oxides (SOx), carcinogenic hydrocarbons such as benzopyrene, etc. Because of the fine particles, they are more easily penetrated into the respiratory tract and lungs of the human body, and are annoying entities that hinder the health of the Japanese people.
[0003]
As a method for removing both nitrogen oxides and particulate matter, a method has conventionally been proposed in which a denitration device (nitrogen oxide removal device) including a denitration catalyst and a dust collector such as a bag filter or an electric dust collector are provided. ing. Regarding the latter, various bag filters of a dust collection system for filtering and separating high concentration dusts have been developed. For diesel vehicles, a type of diesel black smoke filter (DPF) has been developed that includes a particulate filter and a regenerator to prevent clogging, which can promote particulate matter removal more strongly. Various types of devices are being considered for practical use. However, all of them have technical problems, and at present, a definitive device capable of quantitatively controlling and taking measures against particulate matter contained in diesel exhaust gas has not yet been developed.
[0004]
In addition, a method has been developed in which black smoke emitted by the combustion of carbon-based fuel used in diesel vehicles is collected by a filter and then oxidized, but practical use is difficult because the filter is expensive (Non-Patent Documents 1 to 3). 4, Patent Document 1). On the other hand, black smoke using plasma, although the development processing method of incomplete combustion products and NO _X are underway, these processing methods is limited to the power supply used and the electrode structure, etc., black smoke and NO _X removal Not only are they less effective, costly and difficult to control the plasma, they can even produce other harmful substances. For example, gases such as SO _X and NO _X are removed by a combination of corona discharge and ammonia, but have no remarkable effect on removing solid substances such as black smoke (Patent Documents 2 and 3). The method for reducing NO _X and particulate matter in combination with low-temperature plasma and the catalyst which is generated by using an AC power source (Patent Document 4) have been developed, but this method is to control the low temperature plasma by the AC power source In addition to the difficulty, NO _X can be produced in reverse. DC or with an alternating pressure field, the gas to be treated is introduced between two metal electrodes, black smoke by discharging and NO _X (Patent Document 5), a method of collecting black smoke with a filter and treating the black smoke with NO ₂ generated by plasma treatment (Patent Document 6), and a method of removing NO _{X in} exhaust gas. Methods have been developed for removal using plasma and a catalytic reduction catalyst for hydrocarbons (Patent Documents 7 and 8), but these methods have difficulty in controlling the plasma discharge itself. Nitrogen gas treatment with the active oxygen in the case of (non-patent document 5) there is a possibility of a new generation of detrimental substances NO _X, and other reducing gas addition, use of filters and catalyst is required, which is costly This method is not applicable to exhaust gas treatment of automobiles. Therefore, high efficiency and economically practical possible, for example, black smoke exhausted by the combustion of carbon-based fuels used in such diesel, practical removal techniques incomplete combustion products and NO _X was developed but now Not.
[0005]
[Patent Document 1]
JP-A-11-324652 (Claim 2)
[Patent Document 2]
Japanese Patent Application Laid-Open No. 03-267113 (Claim 1)
[Patent Document 3]
Japanese Patent No. 3101744 (Claim 1)
[Patent Document 4]
JP-A-08-105317 (Claim 1)
[Patent Document 5]
Japanese Unexamined Patent Publication No. Hei 11-512652 (abstract)
[Patent Document 6]
JP 2001-123823 A (Claim 1)
[Patent Document 7]
JP-A-06-106025 (abstract)
[Patent Document 8]
JP 07-247827 A (abstract)
[Non-patent document 1]
Takayuki Matsuura, “(DPF) Diesel Particulate Removal Filter, Key to Promotion of Low-Cost Attention in Diesel Vehicle Emission Control,” Nikkei Ecology, Nikkei BP, June 2000, p. 39-43
[Non-patent document 2]
Makoto Inomata, "Purification Catalyst for Diesel Exhaust Gas", Eco Industry, CMC Co., Ltd., February 2001, Vol. 6, No. 2, p. 27-37
[Non-Patent Document 3]
Editorial Department, "Diesel Engine Exhaust Gas Countermeasures and Market", Eco Industry, CMC Co., Ltd., June 2001, Vol. 6, No. 4, p. 46-51
[Non-patent document 4]
Isao Kataoka, "Current Status and Future Prospects of Filter Technology for Removal of Suspended Particulate Matter (SPM) from Diesel Engines", Eco Industry, CMC Corporation, September 2001, Vol. 6, No. 9, p. 24-30
[Non-Patent Document 5]
Masazumi Fujiwara, et al., "Effects of oxygen and water vapor on discharge denitration method", http: // www. etl. go. jp / jp / results / bulletin / pdf / 62-5 / Fujiwara150. pdf, August 29, 2002.
[0006]
[Problems to be solved by the invention]
The present invention aims at providing black smoke generated by the combustion of the carbon-based fuel, incomplete combustion products, a highly efficient and economically practical possible processing methods and apparatus of the NO _X hazardous substances.
[0007]
[Means for Solving the Problems]
According to the present invention, particularly, black smoke and / or incompletely combusted matters of exhaust gas generated by combustion of carbon-based fuel are efficiently removed. In the present invention, black smoke is, for example, a particulate matter contained in exhaust gas of a diesel engine and contains carbon and hydrocarbon as main components. The present inventors have, on how to be removed NO _X if it contains more NO _X black smoke and / or incomplete combustion products, or in the exhaust gas in the exhaust gas generated by the combustion of carbon-based fuels As a result of intensive studies to solve the above-mentioned various problems of the methods developed so far, black smoke or / and incompletely combusted substances in exhaust gas generated by combustion of carbon-based fuel, particularly It was found that black smoke was efficiently attached or adsorbed on the dielectric surface. Further, the present inventors apply a pulse voltage to a metal electrode provided on a dielectric surface while adhering or adsorbing black smoke or / and incompletely combusted substances in exhaust gas on the surface of the dielectric material, and apply the pulse voltage along the dielectric surface. If further contains NO _X black smoke and / or incomplete combustion products in the exhaust gases, or in the exhaust gas by contacting with a pulse corona creeping discharge generated Te can also be removed NO _X, It has been found that the above problem can be solved. Further studies have led to the completion of the present invention.
[0008]
That is, the present invention
(1) The exhaust gas generated by the combustion of the carbon-based fuel is brought into contact with a pulse corona discharge generated along the dielectric surface by applying a pulse voltage to a metal electrode provided on the dielectric surface. method for removing harmful substances in the exhaust gas, characterized by also removing NO _X If the black smoke and / or incomplete combustion products, or include further NO _X in the exhaust gas,
(2) The method according to (1), wherein the dielectric has at least one or more treated surfaces, and the thickness of the dielectric is in a range of 0.1 to 50 mm.
(3) The metal electrode provided on the dielectric surface has a square, circular or arbitrary shaped hole, and the metal electrode is provided or buried on the dielectric surface. 2) The method according to any of the above,
(4) The method according to any one of (1) to (3), wherein the metal electrode has a mesh shape.
(5) The pulse voltage is always positive, always negative or positive and negative are alternately applied, the peak absolute value of the pulse voltage is 100 V to 50 kV, the rise time of the pulse voltage is 10 ns to 0.01 s, and the pulse voltage is The method according to any one of (1) to (4), wherein the half width of the pulse voltage is 0.01 μs to 0.01 s, and the frequency of the pulse voltage is in the range of 1 Hz to 500 kHz.
(6) Exhaust gas generated by combustion of carbon-based fuel, comprising: a dielectric; a metal electrode provided or embedded on the dielectric surface; a pulse voltage supply; and a pulse frequency controller. device also remove NO _X when the black smoke and / or incomplete combustion of gas, or include further NO _X in the exhaust gas,
About.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described.
[0010]
The present invention relates to a method for removing exhaust gas generated by the combustion of carbon-based fuel while adhering or adsorbing black smoke or / and incompletely combusted substances in the exhaust gas generated by combustion of the carbon-based fuel on the dielectric surface. A pulse voltage is applied to a metal electrode provided on the surface to make contact with a pulse corona discharge generated along the surface of the dielectric, thereby causing black smoke and / or incompletely combusted substances in the exhaust gas or further into the exhaust gas. A pulse corona treatment method characterized by removing NO _X when NO _X is included.
[0011]
Next, an embodiment of the present invention will be specifically described with reference to FIG. That is, the exhaust gas generated by the combustion of the carbon-based fuel is guided to the gas inlet 8, and black smoke or / and incompletely combusted matter (hereinafter simply referred to as black smoke in the following examples) is included in the exhaust gas. However, in a state where no pulse corona surface discharge occurs, the exhaust gas flow path (gap between the glass tube 3 and the alumina tube 4) is utilized by utilizing the characteristic of efficiently adhering to the surface of the derivative (alumina tube 4). The smoke is collected by adsorbing or adhering black smoke on the surface of the derivative (alumina tube 4) located inside. Next, a pulse voltage is applied between the silver wire 5 which is a metal electrode wound around the surface of the dielectric (alumina tube 4) and the stainless steel rod 6, that is, between the anode 1 and the cathode 7 to apply the pulse voltage to the dielectric (alumina tube 4). 4) Generate a pulse corona creeping discharge along the surface. Due to the pulse corona surface discharge, black smoke mainly changes into CO ₂ and CO. It is more complicated if there are more NO _X. The generation of the pulse corona surface discharge, nitrogen oxides if they contain NO _X in the exhaust gas (NO), and oxygen from the _{(O 2)} or the like, when the nitrogen dioxide NO _X is contained in the exhaust gas _(NO 2) , And reactive oxygen active species in the form of oxygen atoms (O ^* ), ozone (O ₃ ) and OH are produced.
NO + O ^* → NO ₂ ... (1)
The generated NO ₂ is used to promote the oxidation of black smoke and the like collected on the surface of the dielectric (alumina tube 4). The reaction that proceeds here is, for example, C + 2NO ₂ becomes CO ₂ + CO + 2NO. _Furthermore, ^O * + C = CO, the oxidation of _{O 3 + C → CO + CO} 2 + O 2, 2OH + C = CO + H 2 O and made of carbon is carried out by other reactive substances. Next, for example, the generated CO reduces NO and NO ₂ to become 2CO + 2NO = N ₂ + 2CO ₂ and 4CO + 2NO ₂ = N ₂ + 4CO ₂ . When NO _X is present in the exhaust gas flowing through the pulse corona generation field and the space around the pulse corona generation field, the NO _X is oxidized (reaction (1)) or decomposed (reaction (2)).
2NO → N ₂ + O ₂ (2)
In this way, when the pulse corona surface discharge is not generated, the black smoke is trapped on the surface of the dielectric (alumina tube 4) by adhesion or adsorption, and the pulse voltage is applied between the anode 1 and the cathode 7 sandwiching the dielectric. When a pulse corona creeping discharge is generated around the surface of the derivative (alumina tube 4) and around the silver wire 5 when applied, the black smoke adhering or adsorbed on the surface of the derivative (alumina tube 4) is oxidized and decomposed as described above. If there is NO _X flowing in the pulse corona generation field and the space around it, it is reduced and decomposed as described above, and for example, C, CO, NO, NO ₂ is detoxified into CO ₂ , N ₂ , O _2, etc. From the gas outlet 9. The incomplete combustion products flowing through the pulse corona generating hall and the space around them, for example a hydrocarbon _C m _{H n} is _CO 2, CO, the _{H 2} O, in a similar manner further CO is oxidized to CO ₂ The gas is discharged from the gas outlet 9.
[0012]
The pulse corona creeping discharge that occurs between the dielectric surface and the electrode has a deep relationship with the thickness of the dielectric, and the applied pulse voltage must be increased as the thickness of the dielectric increases, resulting in the efficiency of the pulse power supply. Gets worse. If the dielectric is too thin, the dielectric may be damaged by the voltage applied to the dielectric and the high temperature exhaust gas. Generally, the thickness of the dielectric is preferably about 0.1 to about 50 mm, more preferably about 1 to about 30 mm.
[0013]
Corona creeping discharge in the case of using a dielectric mainly occurs between the metal electrode and the dielectric surface. Therefore, a conductive metal electrode and a dielectric surface are indispensable. As a material of the electrode, a metal having low resistance, such as iron, stainless steel, copper, and aluminum, can be used. The shape of the electrode may be any as long as the object of the present invention is achieved, and examples thereof include a linear shape, a net shape, a rod shape, and a plate shape. Preferably it is a mesh. In the case of a plate shape, it is preferable to have a hole of, for example, a square, a circle or an arbitrary shape. Any material that can generate a pulse corona surface discharge between the electrode and the dielectric to remove black smoke and the like as described above may be used. In this case, the metal electrode may be provided on the dielectric surface, or a part of the metal electrode may be embedded in the dielectric surface. Preferably, a metal electrode is provided on the dielectric surface.
[0014]
As a material of the dielectric, a strong material, for example, alumina, titanium oxide, glass, quartz, ceramics or the like can be used. The shape of the dielectric can be a plate shape, a tubular shape, or the like, and a plate shape is preferable. It is preferable that the surface shape of the dielectric is made uneven to secure the occurrence of discharge and to enlarge the discharge space.
[0015]
The pulse power supply is used for pulse corona discharge after storing electric energy in a capacitor or a coil. Therefore, it is necessary to adjust the charging time of the pulse voltage, the rising time, and the time width of the pulse corona discharge. When the pulse frequency is set in the range of about 1 Hz to about 500 kHz, the half width of the pulse voltage is set to about 1 ns to about 0.01 s. Considering the characteristics of the dielectric, the half width of the pulse voltage is preferably about 0.01 μs to about 0.01 s. Irrespective of whether the pulse voltage is always positive, always negative, or both positive and negative, a pulse corona surface discharge occurs. The peak absolute value of the pulse voltage is related to the thickness of the dielectric and the energy input per unit pulse, and the peak absolute value of the pulse voltage is preferably in the range of about 100 V to 50 kV.
[0016]
For example, in the case of a combustion engine such as a car, the emission amount of harmful substances such as black smoke NO _X in the combustion exhaust gas is determined by the engine speed, the fuel injection speed, the vehicle running speed, and the generator speed related to the engine speed. Number, engine operating characteristics including engine load, and combustion characteristics of the internal combustion engine. Utilizing the characteristic that the amount of black smoke emitted increases in proportion to the fuel consumption per revolution, the fuel injection speed or the engine speed, load magnitude, running speed, generator related to the fuel injection speed The pulse voltage is fixed on the basis of the rotation speed and the power generation capacity of the device, and the pulse frequency is adjusted by using a pulse frequency control device, so that black smoke or the like can be processed. The combustion exhaust gas may be directly subjected to the removal method of the present invention, or may be diluted with an appropriate gas (for example, air) and subjected to the removal method of the present invention. The dilution ratio may usually be about 1.5 to 400 times by volume. If the amount of discharge of black smoke is large, or increasing the pulse frequency, by reducing the pulse frequency when a small amount discharge of black smoke, further NO _X black smoke or the like, or in the exhaust gas If it is included, it is possible to efficiently and economically safely discharge NO _X that satisfies the emission standard.
[0017]
【Example】
The present invention will be described with reference to examples, but the present invention is not limited to these examples.
About diesel engines;
Exhaust gas from a diesel engine (total displacement: 2L) using diesel light oil fuel is diluted with air to measure black smoke emission [Measurement method: continuous filter type, equipment used: TEOM 1105, equipment manufacturer: Rupprecht & Patashick Co. , Inc. The relationship between this and the shaft output is shown in FIG. 2 (where the dilution ratio of the exhaust gas used for measurement at each engine speed with air is 1.0 krpm: 141 volumes, 1.5 krpm: 154 volumes). 2.0 krpm: 82 times the volume, 3.0 krpm: 347 times the volume). Irrespective of the rotation speed, the emission of black smoke per hour increased potential. It should be noted that this type of engine can comply with the black smoke emission regulations of 1993, but cannot comply with the new emission regulations of 1997 or later. Particulate matter (PM)). On the other hand, the relationship between the NO _X concentration and the shaft output is shown in FIG. 3 (where the dilution ratio of the exhaust gas used for measurement at each engine speed is 2.5 krpm: 347 volume times, and the other engine speed is 2 krpm. , 3 krpm was the same as in FIG. 2). As is clear from the figure, the emission concentration of NO is about 90 ppm or more in the case of 2 krpm or more and increases in proportion to the load of the engine. In addition, most of the NO _X is NO. ₂ was found to be about 10 ppm. (Analysis method of NO _X : chemiluminescence method, equipment used: NO · NO ₂ · NO _X analyzer ECL-880 US, equipment maker: Anatech Yanaco Co., Ltd.)
[0018]
[Example 1]
A silver wire 5 (diameter: 0.5 mm, number of turns) wound from the exhaust pipe of a diesel engine to the surface of an alumina tube 4 (outer diameter: 10 mm, inner diameter: 6 mm, length: 200 mm) of the pulse corona surface discharge reactor in FIG. : 14 times, the black smoke previously collected in the winding length (the length of the alumina tube 4 where the silver wire is wound: 50 mm) was oxygen (10%) and While flowing a mixed gas of nitrogen (90%), a pulse power supply (DP-10K10, rise time: about 25 ns, half-width of pulse voltage: about 700 ns, manufactured by Pulse Electronics Technology Co., Ltd.) between the anode 1 and the cathode 7 Was used to apply a pulse voltage (peak voltage: 7 kV), the frequency was changed to 1 kHz, 2 kHz, and 3 kHz, and a gas generated by generating a pulse corona surface discharge was analyzed. Oxygen: Nitrogen = 1: was the mixing ratio of 9 was determined based on the analysis of exhaust gas of a diesel engine (Fig. 4) (N _2, O 2 analytical methods: analysis by gas chromatography, using equipment: AGC280, equipment manufacturer: Okura Riken Co., Ltd.). As a result, black smoke as is clear from FIG. 5 is changed mainly to CO and CO ₂ (CO and CO ₂ Analysis method: Analysis by gas chromatography, using equipment: GC103, equipment manufacturers: Riken Okura Co.) . It is considered that the oxidation reaction and the reduction reaction are simultaneously occurring in the pulse corona discharge field since CO having the reduction reaction ability is generated. No new NO _X was found. Since the ability to remove black smoke has a maximum of 1 mg / hour, it is considered that practical application of black smoke treatment for exhaust gas from an engine is preferably possible by preferably increasing the reaction area and improving the shape of the reactor.
[0019]
[Example 2]
After diluting 0.36 L / min exhaust gas of a diesel engine 2.9 times with air, the pulse corona surface discharge reactor [in this case, an aluminum wire 5 (diameter: 0.5 mm, A pulse voltage is applied between the anode 1 and the cathode 7 while the winding number is 68 times and the winding length (the length of the alumina tube 4 where the aluminum wire is wound is 85 mm). As a result of analyzing the processing effect of black smoke by generating a pulse corona surface discharge, when the frequency is 1 kHz and the pulse voltage is 7.2 kV (peak), the processing capacity of black smoke is 0.45 mg / hour, and the black smoke is removed. The rate was 89% by weight, and the NO _X removal rate was 40% by weight (FIG. 6).
[0020]
[Example 3]
After diluting 0.15 L / min exhaust gas of a diesel engine 20 times with air, the pulse corona was introduced into the pulse corona creeping discharge reactor (in this case, using aluminum wire 5) in FIG. As a result of analyzing the processing effect of black smoke by generating discharge, when the pulse peak voltage is 5 kV and the pulse frequency is 1 kHz, 2 kHz, and 4 kHz, the processing capacity of black smoke is 0.11, 0.13, and 0.1, respectively. The amount of black smoke was 28% by weight, 19% by weight and 31% by weight, respectively. The removal rates of NO _X were 68%, 86% and 90% by weight, respectively.
[0021]
[Example 4]
A gas obtained by diluting the exhaust gas of the diesel engine at 0.015 L / min 200 times with air was introduced into the pulse corona surface discharge reactor (in this case, using the aluminum wire 5) in FIG. As a result of analyzing the black smoke treatment effect by generating a pulse corona discharge (pulse peak voltage: 5.5 kV, frequency: 2 kHz), the processing capability of black smoke was 0.04 mg / hour at maximum and the black smoke removal rate Was 50% by weight. In addition, the concentration of black smoke could be reduced to at least 0.2 mg / m ³ . The removal rate of NO _X was 50 to 60% by weight.
[0022]
【The invention's effect】
The present invention, and methods also remove high efficiency and economically NO _X when the black smoke and / or incomplete combustion products generated by the combustion of carbon-based fuels, or include further NO _X in the exhaust gas An apparatus for removing can be provided.
[Brief description of the drawings]
FIG. 1 shows a sectional view of a pulse corona surface discharge reactor.
FIG. 2 shows the relationship between black smoke (particulate matter “PM”) emission speed (g / h) and shaft output (kW).
FIG. 3 shows the relationship between NO _X concentration (ppm) and shaft output (kW).
FIG. 4 shows the relationship between the concentration of exhaust components (%) and the experiment time (second).
FIG. 5 shows the relationship between the selectivity (%) of CO / CO ₂ and the time (minutes).
FIG. 6 shows a relationship between black smoke (particulate matter “PM”) emission rate (g / h), NO _X concentration (ppm), and time (minute).
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Anode 2 Stainless steel joint tube 3 Glass tube 4 Alumina tube 5 Silver wire or aluminum wire 6 Stainless steel rod 7 Cathode 8 Gas inlet 9 Gas outlet 10 Insulator

Claims (6)

The exhaust gas generated by the combustion of the carbon-based fuel is brought into contact with a pulse corona discharge generated along the dielectric surface by applying a pulse voltage to a metal electrode provided on the surface of the dielectric to produce black smoke in the exhaust gas. and / or method for removing harmful substances in the exhaust gas, characterized by also removing NO _X when the incomplete combustion product, or further contains NO _X in the exhaust gas. The method of claim 1, wherein the dielectric has at least one or more treated surfaces, and the thickness of the dielectric ranges from 0.1 to 50 mm. The metal electrode provided on the dielectric surface has a square, circular or arbitrary shaped hole, and the metal electrode is provided or buried on the dielectric surface. The method described in. The method according to any one of claims 1 to 3, wherein the metal electrode is reticulated. The pulse voltage is always positive, always negative or positive and negative are alternately applied, the peak absolute value of the pulse voltage is 100 V to 50 kV, the rise time of the pulse voltage is 10 ns to 0.01 s, and the half width of the pulse voltage 5. The method according to claim 1, wherein the pulse voltage is in the range of 0.01 μs to 0.01 s, and the frequency of the pulse voltage is in the range of 1 Hz to 500 kHz. Dielectric, metal electrodes installed or buried on the dielectric surface, a pulse voltage supply and a pulse frequency control device, characterized in that it comprises: A device that removes black smoke and / or incompletely combusted substances, or NO _X when exhaust gas further contains NO _X.

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