JP2006329090A - Particulate matter processing device - Google Patents
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- 239000013618 particulate matter Substances 0.000 title claims abstract description 97
- 239000003054 catalyst Substances 0.000 claims abstract description 131
- 230000005684 electric field Effects 0.000 claims abstract description 9
- 230000001939 inductive effect Effects 0.000 claims abstract 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical group [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 11
- 238000010438 heat treatment Methods 0.000 claims description 9
- 239000000919 ceramic Substances 0.000 claims description 6
- 238000011144 upstream manufacturing Methods 0.000 claims description 6
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- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 21
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 4
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- 230000005686 electrostatic field Effects 0.000 description 4
- 229910052697 platinum Inorganic materials 0.000 description 4
- 230000008929 regeneration Effects 0.000 description 4
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- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
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- 239000011593 sulfur Substances 0.000 description 2
- 206010007269 Carcinogenicity Diseases 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
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- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
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- 239000000295 fuel oil Substances 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 239000010687 lubricating oil Substances 0.000 description 1
- 230000008520 organization Effects 0.000 description 1
- 229910052574 oxide ceramic Inorganic materials 0.000 description 1
- 239000011224 oxide ceramic Substances 0.000 description 1
- 239000011236 particulate material Substances 0.000 description 1
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- 239000010948 rhodium Substances 0.000 description 1
- 229910052703 rhodium Inorganic materials 0.000 description 1
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 1
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- 150000003464 sulfur compounds Chemical class 0.000 description 1
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Abstract
Description
本発明は、ディーゼルエンジンから排出される排ガス中に含まれる粒子状物質を分解処理する粒子状物質処理装置に関する。 The present invention relates to a particulate matter processing apparatus for decomposing particulate matter contained in exhaust gas discharged from a diesel engine.
ディーゼルエンジンは、ガソリンエンジンに比べて熱効率が良く燃費の点で優れているため、バスやトラック等の大型のディーゼル車に利用されている。しかしながら、ディーゼルエンジンは、有害な粒子状物質（ＰＭ：パティキュレートマター）や窒素酸化物（ＮＯＸ）を排ガス中に多く含む傾向がある。この粒子状物質は、ディーゼルエンジンから排出される粒子状の物質の総称で、一般に、炭素からなる黒煙（煤）の周囲に、燃え残った燃料や潤滑油の成分（ＳＯＦ）や、軽油燃料中の硫黄分から生成される硫黄化合物（サルフェート）等が吸着しているものと考えられている。尚、ディーゼルエンジンから排出された直後の初期の粒子状物質は、黒煙（煤）に炭化する前のアスファルト等の重合炭化水素の粒状体と考えられる。 Diesel engines are used in large diesel vehicles such as buses and trucks because they have better thermal efficiency and better fuel efficiency than gasoline engines. However, diesel engines, harmful particulate matter (PM: particulate matter) and nitrogen oxides (NO X) tend to contain a number in the exhaust gas. This particulate matter is a general term for particulate matter emitted from diesel engines. Generally, fuel and lubricating oil components (SOF), light oil fuel, and so on are left around carbon black smoke (soot). It is considered that sulfur compounds (sulfate) and the like produced from the sulfur content therein are adsorbed. The initial particulate matter immediately after being discharged from the diesel engine is considered to be a granular material of polymerized hydrocarbons such as asphalt before carbonizing into black smoke (soot).
また、大気中の粒子状物質の人体に及ぼす影響が指摘されており、多くの場合発がん性を有する等人体に有害であるため、近年、粒子状物質の排出が厳しく規制されている。 In addition, the influence of particulate matter in the atmosphere on the human body has been pointed out, and in many cases it is harmful to the human body, such as having carcinogenicity, so in recent years the emission of particulate matter has been severely regulated.
ディーゼルエンジンの排ガス中の粒子状物質や窒素酸化物の低減するための対策として、大別して２つの手法がある。一つは、エンジン本体の燃焼技術の改良により、粒子状物質や窒素酸化物の低減を図るものであり、他の一つは、ディーゼルエンジンに排ガス後処理装置を装着して、後処理装置によって粒子状物質や窒素酸化物の低減を図るものである。 There are roughly two methods for reducing particulate matter and nitrogen oxides in exhaust gas from diesel engines. One is to reduce particulate matter and nitrogen oxides by improving the combustion technology of the engine body, and the other is to install an exhaust gas aftertreatment device on the diesel engine and use the aftertreatment device. It is intended to reduce particulate matter and nitrogen oxides.
ところで、窒素酸化物は完全燃焼状態により生成され易い傾向があるのに対し、粒子状物質は不完全燃焼状態で生成され易い傾向があり、両者に相反する関係があるため、前者のエンジン本体の燃焼技術の改良では、窒素酸化物の排出を抑えながら粒子状物質の排出の低減を図るのは困難な状況にある。そのため、現状では、後者の後処理装置による粒子状物質や窒素酸化物の低減が一般的に採用されている。 By the way, while nitrogen oxides tend to be generated easily in a completely burned state, particulate matter tends to be easily generated in an incompletely burned state. In the improvement of combustion technology, it is difficult to reduce the emission of particulate matter while suppressing the emission of nitrogen oxides. Therefore, at present, reduction of particulate matter and nitrogen oxides by the latter post-treatment apparatus is generally employed.
粒子状物質の排出を低減するための後処理装置としては、排ガス中の粒子状物質をフィルタで物理的に捕集するＤＰＦ（ディーゼル・パティキュレート・フィルタ）が広く用いられている。特に、フィルタで捕集した粒子状物質が堆積して目詰まりを起こし排ガスの圧力損失が大きくなるのを防止するために、堆積した粒子状物質を除去してフィルタを再生可能な再生式ＤＰＦ（手動再生式ＤＰＦ、自動再生式ＤＰＦ、連続再生式ＤＰＦ等）が広く使用されており、中でも、フィルタによる粒子状物質の捕集機能と、触媒の酸化作用によりフィルタを再生する機能を備えた連続再生式ＤＰＦが、最も効果的で、注目されている。 As a post-treatment device for reducing particulate matter emission, DPF (diesel particulate filter) that physically collects particulate matter in exhaust gas with a filter is widely used. In particular, in order to prevent the particulate matter collected by the filter from accumulating and causing clogging and increasing the pressure loss of the exhaust gas, a regenerative DPF that removes the accumulated particulate matter and regenerates the filter ( Manual regeneration type DPF, automatic regeneration type DPF, continuous regeneration type DPF, etc.) are widely used, and in particular, continuous with a function of collecting particulate matter by a filter and a function of regenerating the filter by an oxidizing action of a catalyst. Regenerative DPF is the most effective and attracting attention.
以上のディーゼルエンジンに排ガス処理に関する解説として、下記の非特許文献１に開示がある。 The following Non-Patent Document 1 discloses the above-described diesel engine regarding exhaust gas treatment.
連続再生式ＤＰＦには、以下に示すような問題点がある。第１に、物理的なフィルタを備えているため、処理効率を上げようとすると、フィルタの目を細かくする必要がある。しかしながら、フィルタの目を細かくすると圧力損失が増えるため、所要の圧力損失に抑えようとすると触媒層が大きくなるという欠点があった。 The continuous regeneration type DPF has the following problems. First, since a physical filter is provided, it is necessary to make the filter finer in order to increase processing efficiency. However, since the pressure loss increases when the filter is made finer, there is a disadvantage that the catalyst layer becomes large if it is attempted to suppress the required pressure loss.
第２に、排ガスの全量が触媒層を通過するため、特に酸化力の強い白金触媒を使うと排ガス中のＳＯ２が酸化されてＳＯ３となり、排ガス中で硫酸が生成され下流側の排気管が腐食するという問題があった。この問題は、日本においては、製油所の脱硫装置を強化し、軽油燃料中の硫黄分の含有量を低減することにより解決しようとしているが、日本以外では、まだ具体的な対策が取られていない状況である。 Secondly, since the entire amount of exhaust gas passes through the catalyst layer, when a platinum catalyst having a particularly strong oxidizing power is used, SO 2 in the exhaust gas is oxidized to SO 3 , and sulfuric acid is generated in the exhaust gas, and the downstream exhaust pipe There was a problem of corrosion. In Japan, we are trying to solve this problem by strengthening refinery desulfurization equipment and reducing the sulfur content in light oil fuel. However, other than Japan, specific measures are still being taken. There is no situation.
第３に、車の急加速等により排ガス流量が急変した場合、フィルタで一端捕集された粒子状物質が再飛散する可能性がある。また、エンジンの運転条件を変えて排ガス温度を上げ、粒子状物質を酸化処理するとき触媒が過昇温してシンタリングする可能性があった。 Thirdly, when the exhaust gas flow rate suddenly changes due to sudden acceleration of the vehicle, etc., there is a possibility that the particulate matter once collected by the filter is scattered again. In addition, when the exhaust gas temperature is raised by changing the operating conditions of the engine and the particulate matter is oxidized, the catalyst may overheat and sinter.
本発明は、上述の問題点に鑑みてなされたものであり、その目的は、粒子状物質を高効率に除去できるとともに、排ガスの圧力損失増加や排ガス中のＳＯ２の酸化等を効果的に抑制可能な粒子状物質処理装置を提供することにある。 The present invention has been made in view of the above-mentioned problems, and its purpose is to remove particulate matter with high efficiency and to effectively increase the pressure loss of exhaust gas and oxidize SO 2 in the exhaust gas. An object of the present invention is to provide an apparatus for treating particulate matter that can be suppressed.
上記目的を達成するための本発明に係る粒子状物質処理装置は、ディーゼルエンジンから排出される排ガス中に含まれる粒子状物質を分解処理する粒子状物質処理装置であって、前記排ガス中の前記粒子状物質を大気圧プラズマにより荷電させるプラズマ処理装置と、前記プラズマ処理装置から送入される前記排ガス中の荷電した前記粒子状物質を、印加電界により選択的に触媒層に誘導して、前記触媒層の触媒作用によって分解処理する触媒処理装置と、を備えてなることを第１の特徴とする。 In order to achieve the above object, a particulate matter treatment apparatus according to the present invention is a particulate matter treatment apparatus for decomposing particulate matter contained in exhaust gas discharged from a diesel engine, wherein the particulate matter treatment apparatus includes: A plasma processing apparatus for charging the particulate matter with atmospheric pressure plasma, and the charged particulate matter in the exhaust gas sent from the plasma processing apparatus is selectively guided to the catalyst layer by an applied electric field, and The first feature is that it comprises a catalyst treatment device for performing a decomposition treatment by the catalytic action of the catalyst layer.
上記第１の特徴の粒子状物質処理装置によれば、プラズマ処理装置で荷電された粒子状物質が、触媒処理装置内の印加電界により誘起されるクーロン力によって選択的に触媒層に誘導されて分解処理されるため、送入された排ガスから粒子状物質が除去されて排出される。また、フィルタを用いるＤＰＦに比べ粒子状物質の除去率が大幅に向上する。粒子状物質が印加電界によって選択的に触媒層に誘導され、送入された排ガスの大部分は触媒層を通過せずに排出可能であり、物理的なフィルタを使用しないため、排ガスの圧力損失が増加するという従来のＤＰＦにおける問題が解消される。更に、送入された排ガスの大部分は触媒層を通過しないため、触媒層での排ガス中のＳＯ２の酸化が大幅に低減され、触媒処理装置の下流側における排気管の腐食が大幅に低減される。 According to the particulate matter processing apparatus of the first feature, the particulate matter charged in the plasma processing apparatus is selectively guided to the catalyst layer by the Coulomb force induced by the applied electric field in the catalyst processing apparatus. Since the decomposition treatment is performed, the particulate matter is removed from the sent exhaust gas and discharged. In addition, the particulate matter removal rate is greatly improved as compared with the DPF using a filter. Particulate matter is selectively guided to the catalyst layer by the applied electric field, and most of the exhaust gas that is sent in can be discharged without passing through the catalyst layer, and no physical filter is used, so exhaust gas pressure loss This solves the problem of the conventional DPF that increases. Furthermore, since most of the exhaust gas that has been sent does not pass through the catalyst layer, oxidation of SO 2 in the exhaust gas in the catalyst layer is greatly reduced, and corrosion of the exhaust pipe on the downstream side of the catalyst processing device is greatly reduced. Is done.
更に、本発明に係る粒子状物質処理装置は、上記第１の特徴に加え、前記大気圧プラズマが、パルス放電プラズマであることを第２の特徴とする。 Furthermore, in addition to the first feature, the particulate matter processing apparatus according to the present invention has a second feature that the atmospheric pressure plasma is pulsed discharge plasma.
上記第２の特徴の粒子状物質処理装置によれば、プラズマ処理装置内の放電電界が継続的な静電界でないため、プラズマ処理装置内で荷電した粒子状物質が、プラズマ処理装置内の電極で捕集されることなく、排ガスの流れに乗って下流側の触媒処理装置内に誘導され、更に、触媒処理装置内で触媒層に誘導されることになり、上記第１の特徴の作用効果をより効果的に発揮することができる。 According to the particulate matter processing apparatus of the second feature, since the discharge electric field in the plasma processing apparatus is not a continuous electrostatic field, the particulate matter charged in the plasma processing apparatus is transferred to the electrode in the plasma processing apparatus. Without being collected, it is guided into the downstream catalyst processing apparatus by riding on the flow of the exhaust gas, and further guided to the catalyst layer in the catalyst processing apparatus. It can be exhibited more effectively.
更に、本発明に係る粒子状物質処理装置は、上記第１または第２の特徴に加え、前記触媒処理装置に送入される前記排ガスの全流量の１０％以下が、前記触媒層を通過することを第３の特徴とする。 Furthermore, in the particulate matter processing apparatus according to the present invention, in addition to the first or second feature, 10% or less of the total flow rate of the exhaust gas fed to the catalyst processing apparatus passes through the catalyst layer. This is the third feature.
上記第３の特徴の粒子状物質処理装置によれば、排ガスの全流量の１０％以下しか触媒層を通過しないので、排ガスの圧力損失増加、及び、触媒層での排ガス中のＳＯ２の酸化を効果的に抑制できる。 According to the particulate matter treatment apparatus of the third feature, only 10% or less of the total flow rate of the exhaust gas passes through the catalyst layer, so that an increase in the pressure loss of the exhaust gas and oxidation of SO 2 in the exhaust gas in the catalyst layer Can be effectively suppressed.
更に、本発明に係る粒子状物質処理装置は、上記第１乃至第３の何れかの特徴に加え、前記触媒層が、多孔質セラミックスからなる担体に白金族金属の触媒を担持してなることを第４の特徴とする。 Furthermore, in the particulate matter processing apparatus according to the present invention, in addition to any of the first to third features, the catalyst layer is formed by supporting a platinum group metal catalyst on a carrier made of porous ceramics. Is the fourth feature.
上記第４の特徴の粒子状物質処理装置によれば、触媒層に誘導された粒子状物質を触媒酸化して分解する触媒層が具体的に実現される。 According to the particulate matter processing apparatus of the fourth feature, the catalyst layer that specifically decomposes the particulate matter induced in the catalyst layer by catalytic oxidation is realized.
更に、本発明に係る粒子状物質処理装置は、上記第１乃至第４の何れかの特徴に加え、前記触媒層の前記担体の細孔径が、前記触媒層の上流側から下流側に向けて小さくなっていることを第５の特徴とする。 Furthermore, in the particulate matter treatment apparatus according to the present invention, in addition to any of the first to fourth features, the pore diameter of the carrier of the catalyst layer is from the upstream side to the downstream side of the catalyst layer. The fifth feature is that it is smaller.
上記第５の特徴の粒子状物質処理装置によれば、触媒層の上流側から粒径の大きい粒子状物質から順番に担体で捕集して分解処理できるので、触媒層を通過する排ガスの圧力損失の上昇を抑制できる。 According to the particulate matter treatment apparatus of the fifth feature, since the particulate matter having a large particle diameter can be collected and decomposed in order from the upstream side of the catalyst layer, the pressure of the exhaust gas passing through the catalyst layer Increase in loss can be suppressed.
更に、本発明に係る粒子状物質処理装置は、上記第１乃至第５の何れかの特徴に加え、前記触媒層が、前記担体の上流側の端部より担体内部に後退した位置から下流側部分に前記触媒を担持していることを第６の特徴とする。 Furthermore, in the particulate matter processing apparatus according to the present invention, in addition to any one of the first to fifth features, the catalyst layer is located downstream from the position where the catalyst layer is retracted from the upstream end of the carrier. A sixth feature is that the catalyst is supported on the portion.
上記第６の特徴の粒子状物質処理装置によれば、触媒層内に誘導されずに触媒層の上流側表面に沿って通流する排ガス中に含まれるＳＯ２が触媒層により酸化されるのを抑制できる。 According to the particulate matter processing apparatus of the sixth feature, SO 2 contained in the exhaust gas flowing along the upstream surface of the catalyst layer without being guided into the catalyst layer is oxidized by the catalyst layer. Can be suppressed.
更に、本発明に係る粒子状物質処理装置は、上記第１乃至第６の何れかの特徴に加え、前記触媒層内を加熱する加熱手段を備えていることを第７の特徴とする。 Furthermore, in addition to any of the first to sixth features, the particulate matter treatment apparatus according to the present invention has a seventh feature that includes a heating means for heating the inside of the catalyst layer.
上記第７特徴の粒子状物質処理装置によれば、定常状態における触媒層の温度が粒子状物質の酸化分解に不十分である場合でも、例えばエンジン停止時に加熱手段により加熱することにより粒子状物質を分解処理することができる。また、その時の空気流量を制限することにより、触媒の過昇温を防止できる。 According to the particulate matter processing apparatus of the seventh feature, even when the temperature of the catalyst layer in the steady state is insufficient for the oxidative decomposition of the particulate matter, for example, the particulate matter is heated by heating means when the engine is stopped. Can be decomposed. Further, by restricting the air flow rate at that time, it is possible to prevent the catalyst from being overheated.
本発明に係る粒子状物質処理装置（以下、適宜「本発明装置」という。）の実施の形態につき、図面に基づいて説明する。 Embodiments of a particulate matter processing apparatus according to the present invention (hereinafter referred to as “the present apparatus” as appropriate) will be described with reference to the drawings.
図１に示すように、本発明装置１は、プラズマ処理装置１０と触媒処理装置２０を備えて構成される。ディーゼルエンジン２から排出される排ガスＧ１は、先ず、プラズマ処理装置１０に送入され、プラズマ処理装置１０内のグロー放電により発生する大気圧プラズマにより排ガスＧ１中の粒子状物質が荷電される。荷電された粒子状物質を含む排ガスＧ２は、プラズマ処理装置１０から触媒処理装置２０に送入され、排ガスＧ２の一部の排ガスＧ３（例えば、全流量の１０％以下）が、触媒処理装置２０内の主流路２１から分流して触媒層２２を通過して触媒層２２の外側の副流路２３から排出される。残りの排ガスＧ４は、主流路２１をそのまま通過して排出される。ここで、触媒処理装置２０内では、荷電された粒子状物質の略全部（例えば９９％以上）が、印加された静電界によって主流路２１から触媒層２２に向けて誘導されるため、排ガスＧ４中には粒子状物質が含まれないか、或いは、含まれても全体の１％以下程度である。また、排ガスＧ３中の粒子状物質は、触媒層２２に誘導され、触媒層２２で酸化分解されるため、触媒層２２を通過して触媒処理装置２０から排出される排ガスＧ５中には粒子状物質が含まれない。 As shown in FIG. 1, the apparatus 1 of the present invention includes a plasma processing apparatus 10 and a catalyst processing apparatus 20. The exhaust gas G1 discharged from the diesel engine 2 is first sent to the plasma processing apparatus 10, and the particulate matter in the exhaust gas G1 is charged by atmospheric pressure plasma generated by glow discharge in the plasma processing apparatus 10. The exhaust gas G2 containing charged particulate matter is sent from the plasma processing apparatus 10 to the catalyst processing apparatus 20, and a part of the exhaust gas G3 (for example, 10% or less of the total flow rate) is converted into the catalyst processing apparatus 20. The gas is diverted from the inner main flow path 21, passes through the catalyst layer 22, and is discharged from the sub flow path 23 outside the catalyst layer 22. The remaining exhaust gas G4 passes through the main channel 21 as it is and is discharged. Here, in the catalyst processing apparatus 20, almost all of the charged particulate matter (for example, 99% or more) is guided from the main flow path 21 toward the catalyst layer 22 by the applied electrostatic field, and thus the exhaust gas G4. Particulate matter is not contained in it, or even if it is contained, it is about 1% or less of the whole. Further, since the particulate matter in the exhaust gas G3 is guided to the catalyst layer 22 and is oxidized and decomposed in the catalyst layer 22, the particulate matter is contained in the exhaust gas G5 that passes through the catalyst layer 22 and is discharged from the catalyst processing apparatus 20. Contains no substances.
以下、プラズマ処理装置１０と触媒処理装置２０の構成及び動作について説明する。 Hereinafter, configurations and operations of the plasma processing apparatus 10 and the catalyst processing apparatus 20 will be described.
図２に、本実施形態で使用するプラズマ処理装置１０の概略の構成を示す。図２に示すように、プラズマ処理装置１０は、円筒状電極１１とその中心軸上に位置する線状電極１２からなる同軸円筒型電極構造を有し、円筒状電極１１と線状電極１２の間にパルス電源１３を接続して構成される。プラズマ処理装置１０は、パルス電源１３によって両電極１１，１２間にパルス状の放電電界が印加されると、グロー放電による大気圧プラズマが発生し、円筒状電極１１の内部に単極性のイオンが発生する。気体中の微粒子はイオン化され易いので、排ガスＧ１中を浮遊する微粒子である粒子状物質が選択的に荷電される。ここで、大気圧プラズマの発生に係る放電電界がパルス状の間欠的に発生する電界であるため、荷電した粒子状物質は、プラズマ処理装置１０内の電極１１，１２に捕獲されることなく、排ガスＧ１の流れに乗って、プラズマ処理装置１０から触媒処理装置２０へと搬送される。 FIG. 2 shows a schematic configuration of the plasma processing apparatus 10 used in the present embodiment. As shown in FIG. 2, the plasma processing apparatus 10 has a coaxial cylindrical electrode structure composed of a cylindrical electrode 11 and a linear electrode 12 located on the central axis thereof, and the cylindrical electrode 11 and the linear electrode 12 are A pulse power supply 13 is connected between them. In the plasma processing apparatus 10, when a pulsed discharge electric field is applied between the electrodes 11 and 12 by the pulse power supply 13, atmospheric pressure plasma is generated by glow discharge, and unipolar ions are generated inside the cylindrical electrode 11. appear. Since the fine particles in the gas are easily ionized, the particulate matter that is fine particles floating in the exhaust gas G1 is selectively charged. Here, since the discharge electric field related to the generation of the atmospheric pressure plasma is an electric field that is intermittently generated in a pulse shape, the charged particulate matter is not captured by the electrodes 11 and 12 in the plasma processing apparatus 10, It rides on the flow of the exhaust gas G1 and is conveyed from the plasma processing apparatus 10 to the catalyst processing apparatus 20.
図３に、本実施形態で使用する触媒処理装置２０の概略の構成を示す。図３に示すように、触媒処理装置２０は、円筒容器２４内に、断面ドーナツ状で円筒容器２４と同軸の円筒型の触媒層２２が形成されている。円筒容器２４の内壁と触媒層２２の外側面の間に副流路２３が形成される。また、円筒容器２４内には、触媒層２２の外側に、触媒層２２と同軸の円筒状電極２５とその中心軸上に位置する線状電極２６が設けられている。また、両電極２５，２６間に数ｋＶ程度の直流電圧を印加するための直流電源２７が接続されている。尚、図３（Ａ）は、中心軸を含む断面における構成を示し、同図（Ｂ）は、同図（Ａ）の中心軸と直交するＡ−Ａ’断面における構成を示す。 FIG. 3 shows a schematic configuration of the catalyst processing apparatus 20 used in the present embodiment. As shown in FIG. 3, in the catalyst processing apparatus 20, a cylindrical catalyst layer 22 having a donut cross section and coaxial with the cylindrical container 24 is formed in the cylindrical container 24. A sub-flow channel 23 is formed between the inner wall of the cylindrical container 24 and the outer surface of the catalyst layer 22. In the cylindrical container 24, a cylindrical electrode 25 coaxial with the catalyst layer 22 and a linear electrode 26 positioned on the central axis are provided outside the catalyst layer 22. A DC power source 27 for applying a DC voltage of about several kV is connected between the electrodes 25 and 26. 3A shows a configuration in a cross section including the central axis, and FIG. 3B shows a configuration in an A-A ′ cross section orthogonal to the central axis in FIG.
触媒層２２は、断面ドーナツ状で円筒容器２４と同軸の多孔質セラミックスからなる円筒型の担体２８に白金等の白金族金属の触媒を担持して形成される。担体２８は、例えば、アルミナ、ジルコニア、チタニア等の酸化物セラミックスからなる。また、多孔質セラミックスの細孔径は、内側（主流路２１側）から外側（副流路２３側）の方向に、つまり、同軸の軸心より外側ほど小さくなるようになっている。当該構造によって、内側から順番に粒径の大きい粒子状物質から段階的に担体２８に捕集され、触媒層２２の内側表面部での目詰まりを防止でき、排ガスＧ３の圧力損失を必要以上に上昇させずに、粒子状物質を効率的に捕集できる。尚、かかる構造は、セラミックスフィルタでは広く用いられている公知の手法で実現できる。尚、触媒としては、白金以外では、パラジウム、ロジウム等が使用できる。パラジウムは、白金に比べて酸化力が弱いため、排ガスＧ４中のＳＯ２の酸化の程度を軽減する効果がある。 The catalyst layer 22 is formed by supporting a platinum group metal catalyst such as platinum on a cylindrical support 28 made of porous ceramics having a donut cross section and coaxial with the cylindrical container 24. The carrier 28 is made of oxide ceramics such as alumina, zirconia, and titania. In addition, the pore diameter of the porous ceramics becomes smaller in the direction from the inner side (main channel 21 side) to the outer side (sub channel 23 side), that is, the outer side from the coaxial axis. With this structure, particulate matter having a large particle size is collected in stages from the inside to the support 28 step by step, so that clogging at the inner surface portion of the catalyst layer 22 can be prevented, and the pressure loss of the exhaust gas G3 is more than necessary. Particulate matter can be collected efficiently without increasing. Such a structure can be realized by a known method widely used in ceramic filters. As the catalyst, palladium, rhodium, etc. can be used other than platinum. Palladium has an effect of reducing the degree of oxidation of SO 2 in the exhaust gas G4 because it has a weaker oxidizing power than platinum.
更に、触媒層２２の触媒は、担体２８の内側表面近傍（例えば、表面から１００ミクロン程度）を除く部分（図３中、クロスハッチ部分）に、つまり、担体２８の内側表面から外側（担体内部）に向けて後退した位置から外側部分（排ガスＧ３の流れの下流側）に担持されており、主流路２１側に面する部分とその近傍には触媒は存在しない。 Further, the catalyst of the catalyst layer 22 is located in a portion (cross hatched portion in FIG. 3) except for the vicinity of the inner surface of the carrier 28 (for example, about 100 microns from the surface), that is, from the inner surface of the carrier 28 to the outer side ) Is supported on the outer part (downstream side of the flow of the exhaust gas G3) from the position retreated toward (), and there is no catalyst in the part facing the main channel 21 side and in the vicinity thereof.
本実施形態では、触媒処理装置２０には、触媒層２２内を加熱する加熱手段である電気ヒータ２９が設置されている。電気ヒータ２９は、例えば、タングステン線等を担体２８内に埋設して実現される。これにより、定常状態における触媒層２２の温度が粒子状物質の酸化分解に不十分である場合でも、例えば、ディーゼルエンジン２の停止時に電気ヒータ２９により加熱することにより、担体２８に捕集された粒子状物質を分解処理することができる。また、その時の空気流量を制限することにより、触媒の過昇温を防止できる。 In the present embodiment, the catalyst processing apparatus 20 is provided with an electric heater 29 that is a heating means for heating the inside of the catalyst layer 22. The electric heater 29 is realized by, for example, embedding a tungsten wire or the like in the carrier 28. Thereby, even when the temperature of the catalyst layer 22 in the steady state is insufficient for the oxidative decomposition of the particulate matter, the catalyst layer 22 is collected by the carrier 28 by heating with the electric heater 29 when the diesel engine 2 is stopped, for example. Particulate matter can be decomposed. Further, by restricting the air flow rate at that time, it is possible to prevent the catalyst from being overheated.
主流路２１中に存在する荷電した粒子状物質を触媒層２２の方向（外側）に誘導する方向に静電界を発生するために、直流電源２７によって両電極２５，２６間に直流電圧を印加すると、荷電した粒子状物質の略全て（例えば９９％以上）が触媒層２２に誘導される。触媒層２２に誘導された粒子状物質は、触媒層２２の触媒作用により酸化され、その粒子状態が分解し、ＣＯ２として排ガスＧ３とともに排出される。 When a DC voltage is applied between the electrodes 25 and 26 by the DC power source 27 in order to generate an electrostatic field in a direction in which the charged particulate matter existing in the main channel 21 is guided in the direction of the catalyst layer 22 (outside). Almost all of the charged particulate matter (for example, 99% or more) is guided to the catalyst layer 22. Derived particulate matter in the catalyst layer 22 is oxidized by the catalytic action of the catalyst layer 22, the particle state is decomposed and discharged together with the exhaust gas G3 as CO 2.
電極２５，２６間に印加された静電界により主流路２１内から粒子状物質が除去されるため、触媒処理装置２０に送入された排ガスＧ２の大部分（例えば９０％以上）の排ガスＧ４は、粒子状物質が除去された状態で、触媒層２２を通過せずに主流路２１を通流してそのまま排出される。主流路２１を通流する排ガスＧ４は、触媒層２２を通過せず、更に、触媒層２２の内側表面近傍にも触媒が存在しないため、触媒層２２の触媒作用は排ガスＧ４には及ばず、排ガスＧ４中のＳＯ２がＳＯ３に酸化されず、排ガスＧ４中において硫酸が生成されるのが抑制され、触媒処理装置２０の下流側排気管の腐食が抑制される。 Since the particulate matter is removed from the main flow path 21 by the electrostatic field applied between the electrodes 25 and 26, most of the exhaust gas G2 sent to the catalyst processing apparatus 20 (for example, 90% or more) In the state in which the particulate matter is removed, the particulate material passes through the main channel 21 without passing through the catalyst layer 22 and is discharged as it is. The exhaust gas G4 flowing through the main channel 21 does not pass through the catalyst layer 22, and further, there is no catalyst near the inner surface of the catalyst layer 22. Therefore, the catalytic action of the catalyst layer 22 does not reach the exhaust gas G4. The SO 2 in the exhaust gas G4 is not oxidized to SO 3 and the generation of sulfuric acid in the exhaust gas G4 is suppressed, and the corrosion of the downstream exhaust pipe of the catalyst processing device 20 is suppressed.
尚、主流路２１を通過する排ガスＧ４と、触媒層２２及び副流路２３を通過する排ガスＧ３、Ｇ５の流量比は、触媒層２２及び副流路２３における圧力損失を調整することで実現できる。 The flow rate ratio between the exhaust gas G4 passing through the main flow path 21 and the exhaust gas G3 and G5 passing through the catalyst layer 22 and the sub flow path 23 can be realized by adjusting the pressure loss in the catalyst layer 22 and the sub flow path 23. .
本発明装置１を、上記要領でプラズマ処理装置１０と触媒処理装置２０により構成することで、ディーゼルエンジン２から排出される排ガスＧ１の流量が急増した場合にも、触媒処理装置２０の触媒層２２を通過する排ガスＧ３の流速は必要以上に速くならず、担体２８で捕集された状態の粒子状物質が再飛散する可能性は低い。 Even if the flow rate of the exhaust gas G1 exhausted from the diesel engine 2 is rapidly increased by configuring the inventive device 1 with the plasma processing device 10 and the catalyst processing device 20 in the above manner, the catalyst layer 22 of the catalyst processing device 20 is used. The flow rate of the exhaust gas G3 passing through the gas does not become higher than necessary, and the possibility that the particulate matter collected by the carrier 28 is scattered again is low.
以下に、本発明に係る粒子状物質処理装置の別実施形態につき説明する。 Hereinafter, another embodiment of the particulate matter processing apparatus according to the present invention will be described.
〈１〉上記実施形態では、プラズマ処理装置１０に使用する電極構造として、同軸円筒型電極構造のものを例示したが、同電極構造は、同軸円筒型電極構造に限定されるものではない。 <1> In the above embodiment, the electrode structure used in the plasma processing apparatus 10 is exemplified by the coaxial cylindrical electrode structure, but the electrode structure is not limited to the coaxial cylindrical electrode structure.
〈２〉上記実施形態では、主流路２１を通過した排ガスＧ４と副流路２３を通過した排ガスＧ５は、夫々別々に触媒処理装置２０から排出される場合を例示したが、副流路２３が触媒処理装置２０内で主流路２１と合流するように構成し、排ガスＧ４と排ガスＧ５が触媒処理装置２０内で合流してから排出するようにしても構わない。 <2> In the above embodiment, the exhaust gas G4 that has passed through the main flow channel 21 and the exhaust gas G5 that has passed through the sub flow channel 23 have been illustrated as being separately discharged from the catalyst processing apparatus 20, but the sub flow channel 23 is A configuration may be adopted in which the main flow path 21 is merged in the catalyst processing apparatus 20, and the exhaust gas G <b> 4 and the exhaust gas G <b> 5 are merged in the catalyst processing apparatus 20 and then discharged.
〈３〉上記実施形態では、触媒処理装置２０において、触媒層２２の内側に主流路２１を、外側に副流路２３が形成される構造としたが、主流路２１と副流路２３の配置を反転させ、触媒層２２の外側に主流路２１を、内側に副流路２３が形成される構造としても構わない。この場合、担体２８の多孔質セラミックスの細孔径は、外側（主流路２１側）から内側（副流路２３側）の方向に、つまり、同軸の軸心に近いほど小さくなるようにするのが好ましい。更に、触媒層２２の触媒は、担体２８の外側表面近傍を除く部分、つまり、担体２８の外側表面から内側（担体内部）に向けて後退した位置から内側部分に担持され、主流路２１側に面する部分とその近傍には触媒は存在しないようにするのが好ましい。 <3> In the above embodiment, the catalyst processing apparatus 20 has a structure in which the main flow path 21 is formed inside the catalyst layer 22 and the sub flow path 23 is formed outside, but the arrangement of the main flow path 21 and the sub flow path 23 is used. The main channel 21 may be formed outside the catalyst layer 22 and the sub channel 23 may be formed inside. In this case, the pore diameter of the porous ceramics of the carrier 28 should be made smaller in the direction from the outer side (main channel 21 side) to the inner side (sub channel 23 side), that is, closer to the coaxial axis. preferable. Further, the catalyst of the catalyst layer 22 is supported on the inner portion from the portion excluding the vicinity of the outer surface of the carrier 28, that is, the position retracted from the outer surface of the carrier 28 toward the inner side (inside the carrier). It is preferred that no catalyst be present in the facing portion and in the vicinity thereof.
〈４〉上記実施形態では、触媒処理装置２０に使用する電極構造として、同軸円筒型電極構造のものを例示したが、同電極構造は、同軸円筒型電極構造に限定されるものではない。例えば、平行平板型電極構造としても構わない。この場合は、平行平板型電極間に、断面直方体の平板状の触媒層を使用し、一方の平板型電極と触媒層の間に主流路が形成され、他方の平板型電極と触媒層の間に副流路が形成される。また、平行平板型電極を複数組設け、その間に夫々触媒層を設けるようにしても構わない。 <4> In the above embodiment, the electrode structure used in the catalyst treatment apparatus 20 is exemplified by the coaxial cylindrical electrode structure, but the electrode structure is not limited to the coaxial cylindrical electrode structure. For example, a parallel plate type electrode structure may be used. In this case, a flat catalyst layer having a rectangular parallelepiped cross section is used between the parallel plate electrodes, a main flow path is formed between one flat electrode and the catalyst layer, and the other flat plate electrode is between the catalyst layer. A sub-flow channel is formed at the bottom. Further, a plurality of parallel plate electrodes may be provided, and a catalyst layer may be provided between them.
〈５〉上記実施形態では、触媒処理装置２０に、触媒層２２内を加熱する電気ヒータ２９を設置したが、定常状態における触媒層２２の温度が粒子状物質の酸化分解に十分な場合には、必ずしも設けなくても構わない。 <5> In the above-described embodiment, the electric heater 29 for heating the inside of the catalyst layer 22 is installed in the catalyst processing apparatus 20, but when the temperature of the catalyst layer 22 in a steady state is sufficient for the oxidative decomposition of the particulate matter , It does not necessarily have to be provided.
本発明に係る粒子状物質処理装置は、ディーゼルエンジンから排出される排ガス中に含まれる粒子状物質の分解処理に利用可能である。 The particulate matter treatment apparatus according to the present invention can be used for the decomposition treatment of particulate matter contained in exhaust gas discharged from a diesel engine.
１： 本発明に係る粒子状物質処理装置
２： ディーゼルエンジン
１０： プラズマ処理装置
１１： 円筒状電極
１２： 線状電極
１３： パルス電源
２０： 触媒処理装置
２１： 主流路
２２： 触媒層
２３： 副流路
２４： 円筒容器
２５： 円筒状電極
２６： 線状電極
２７： 直流電源
２８： 担体
２９： 加熱手段（電気ヒータ）
Ｇ１： ディーゼルエンジンから排出される排ガス
Ｇ２： プラズマ処理装置から排出される荷電された粒子状物質を含む排ガス
Ｇ３： 触媒層を通過する排ガス
Ｇ４： 触媒層を通過せずに主流路を通過する排ガス
Ｇ５： 触媒層を通過した粒子状物質除去後の排ガス
1: Particulate matter processing apparatus according to the present invention 2: Diesel engine 10: Plasma processing apparatus 11: Cylindrical electrode 12: Linear electrode 13: Pulsed power supply 20: Catalyst processing apparatus 21: Main flow path 22: Catalyst layer 23: Sub Channel 24: Cylindrical container 25: Cylindrical electrode 26: Linear electrode 27: DC power supply 28: Carrier 29: Heating means (electric heater)
G1: Exhaust gas discharged from diesel engine G2: Exhaust gas containing charged particulate matter discharged from plasma processing apparatus G3: Exhaust gas passing through catalyst layer G4: Exhaust gas passing through main flow path without passing through catalyst layer G5: Exhaust gas after removal of particulate matter that has passed through the catalyst layer
Claims (7)
前記排ガス中の前記粒子状物質を大気圧プラズマにより荷電させるプラズマ処理装置と、
前記プラズマ処理装置から送入される前記排ガス中の荷電した前記粒子状物質を、印加電界により選択的に触媒層に誘導して、前記触媒層の触媒作用によって分解処理する触媒処理装置と、
を備えてなることを特徴とする粒子状物質処理装置。 A particulate matter treatment apparatus that decomposes particulate matter contained in exhaust gas discharged from a diesel engine,
A plasma processing apparatus for charging the particulate matter in the exhaust gas with atmospheric pressure plasma;
A catalyst processing apparatus for selectively inducing the charged particulate matter in the exhaust gas sent from the plasma processing apparatus to a catalyst layer by an applied electric field and decomposing the catalyst layer by a catalytic action of the catalyst layer;
A particulate matter processing apparatus comprising:
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| JP2005154551A JP2006329090A (en) | 2005-05-26 | 2005-05-26 | Particulate matter processing device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101820994B (en) * | 2007-09-18 | 2014-12-24 | Amo株式会社 | Monolith, catalyst convertor for purifying exhaust gas using the same and method for manufacturing the catalyst |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101820994B (en) * | 2007-09-18 | 2014-12-24 | Amo株式会社 | Monolith, catalyst convertor for purifying exhaust gas using the same and method for manufacturing the catalyst |
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