JP2011169176A - Exhaust emission control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control system treating particulate matters contained in exhaust gas without applying voltage to an electrode during treatment and treating solid carbon contained in the exhaust gas while generating electricity by using the solid carbon as fuel. <P>SOLUTION: This exhaust emission control system includes a cyclone collector collecting the particulate matters contained in the exhaust gas discharged from an internal combustion engine. In the exhaust emission control system, the particulate matters collected by the cyclone collector are supplied to an electrochemical reactor in a compartment juxtaposed to the cyclone collector and the supplied particulate matters are electrochemically removed by the electrochemical reactor. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an exhaust gas purification system, and more particularly to an exhaust gas purification system that supplies solid carbon in exhaust gas to the anode side and performs an electrochemical treatment.

  Using solid electrolyte with ionic conductivity, unburned particulates such as diesel particulates are deposited on the anode material, and voltage is applied from the outside between both electrodes to electrochemically convert the solid carbon contained in the unburned particulates. A purification device for removal is known (Patent Documents 1 to 5). Such a purifying apparatus moves oxygen ions and the like to the anode side by applying a voltage from the outside, and electrochemically reacts with the solid carbon deposited on the anode material to oxidize and remove the solid carbon. As the solid electrolyte, metal oxides such as zirconia and ceria are used.

  However, it is necessary to always apply a voltage from the outside to these purification apparatuses, and the apparatus itself has no possibility of generating electric power, but rather consumes electric energy. In addition, it was essential to deposit solid carbon on the anode so as to contact the anode material, to form an anode with solid carbon, and to apply a voltage thereto. Therefore, in the technique described in the above document, since the fine particles need to be directly deposited on the anode material, not only means for moving the captured fine particles to the anode side, but also means for moving the captured fine particles to the purification device. There was nothing to be considered about.

  On the other hand, in Patent Document 6, an organic compound such as methane or propane is introduced into an anode, and solid carbon is supported on the anode material by a thermal decomposition reaction of the organic compound. Such “solid carbon supported on the anode material” A power generation method for a solid oxide battery is described, in which a gas is reacted with carbon dioxide to convert it to gaseous carbon monoxide and the gas is oxidized to oxidize the gas.

  This technology is characterized in that solid fuel is used as fuel, whereas ordinary fuel cells use methane or hydrogen as fuel, and the solid carbon supported on the anode reacts electrochemically to generate electricity. To do.

  However, such a power generation method includes an activation step of introducing an organic compound and causing a thermal decomposition reaction to once support solid carbon on the anode as an essential step, and previously supporting solid carbon as a fuel on the anode. Because solid carbon cannot be replenished in the middle of power generation, the fuel cell reaction cannot be continued continuously, and it can be applied directly to power generation systems and electrochemical reactors that require continuous operation. It was difficult to do so, and its technical value could not be fully demonstrated from the viewpoint of practical application.

  Moreover, in the technique described in Patent Document 6, solid carbon used as fuel is not included in the particulate matter in the exhaust gas, but is generated by thermal decomposition of the organic compound gas introduced into the anode in the activation process. The exhaust gas was not purified. In addition, since solid carbon is directly supported on the anode material, not only means for moving the captured fine particles (solid carbon) to the anode side, but also the captured fine particles (solid carbon) are used in the device (solid oxide battery). The means for moving to an electrochemical reactor) has not been studied since it is not necessary.

  In recent years, environmental problems have become serious, and development of an excellent purification system for exhaust gas discharged from an internal combustion engine is desired. In addition, the depletion of organic resources has become serious, and the development of an efficient power generation system is also desired.

JP 2006-198563 A JP 2006-200520 A JP 2006-299857 A JP 2008-119618 A JP 2008-237969 A JP 2008-198585 A

  The present invention has been made in view of the above-described background art, and an object thereof is to provide an exhaust gas purification system that processes particulate matter contained in exhaust gas without applying a voltage to an electrode during processing. Another object of the present invention is to provide an exhaust gas purification system that processes solid carbon contained in exhaust gas while generating power using solid carbon as fuel.

  As a result of intensive studies to solve the above problems, the inventors of the present invention have provided a compartment for storing at least solid carbon as an apparatus configuration, and reacting the solid carbon existing in the compartment with carbon dioxide for the purpose. If the processing method of converting to carbon oxide and generating power by oxidizing the carbon monoxide is adopted, the solid carbon is consumed as fuel, and as a result, continuous power generation is possible and continuous particulate matter It was found that the electrochemical removal of can be performed. Moreover, even if the solid carbon is not directly supported on the anode and is separated from the anode, it can be generated and electrochemically removed from the particulate matter as long as it is stored in a compartment provided on the anode side. I found out.

  Further, in such an electrochemical reactor, since it is not necessary to directly support solid carbon on the anode material as described above, “particulate matter containing solid carbon” collected by a cyclone collector is used. As a result, the inventors have found that the process (power generation and / or removal of particulate matter) can be performed steadily as long as it is supplied to the anode side of the electrochemical reactor without interruption.

  That is, the present invention is an exhaust gas purification system including a cyclone collector that collects particulate matter contained in exhaust gas discharged from an internal combustion engine, and the particulate matter collected by the cyclone collector An exhaust gas purification system characterized in that a substance is supplied to an electrochemical reactor in a compartment attached to a cyclone collector, and the electrochemical reactor electrochemically removes the supplied particulate matter. It is to provide.

  The present invention is also a solid oxide fuel cell in which the electrochemical reactor uses the particulate matter as a fuel, the solid oxide fuel cell having an anode material containing a composite metal oxide, A cathode having a cathode material, and an electrolyte including an ion conductive solid oxide disposed between the anode and the cathode, and reacting solid carbon in the particulate matter with carbon dioxide generated by power generation Thus, the exhaust gas purification system is provided, wherein the exhaust gas purification system is characterized in that power is generated by converting the carbon monoxide into carbon monoxide and oxidizing the carbon monoxide. Hereinafter, this invention is referred to as “embodiment 1”.

  In the present invention, the electrochemical reactor is a solid oxide processing apparatus, and the solid oxide processing apparatus includes an anode having an anode material, a cathode having a cathode material, and an anode and a cathode. At least an electrolyte containing an ion-conducting solid oxide disposed; and by applying a voltage between the anode and the cathode, oxygen ions are transferred to the anode, and the oxygen ions and the particles are formed on the anode. It is an object of the present invention to provide an exhaust gas purification system as described above, which is capable of electrochemically reacting with solid carbon in a substance. Hereinafter, this invention is referred to as “embodiment 2”.

  According to the present invention, the particulate matter collecting part and the electrochemical reactor are arranged independently, and the particulate matter contained in the exhaust gas discharged from the internal combustion engine can be interrupted efficiently and simply. Without being supplied to the anode side of the electrochemical reactor. In particular, it is possible to provide an exhaust gas purification system that processes particulate matter contained in exhaust gas without applying a voltage to the electrode during processing (system operation).

  Moreover, in aspect 1, since solid carbon can be used as fuel instead of hydrogen or organic gas as in a conventional fuel cell, solid carbon contained in particulate matter in exhaust gas can be used, and as a result, power generation However, the solid carbon contained in the particulate matter in the exhaust gas can be treated. Further, the exhaust gas can be continuously purified by continuously continuing the fuel cell reaction.

  Further, in the solid oxide fuel cell according to the present invention, the solid carbon can be removed electrochemically or generated using the solid carbon as a fuel without directly supporting the solid carbon on the anode. Taking advantage of the features, particulate matter in exhaust gas is collected by a cyclone collector, and then on the anode of the solid oxide fuel cell existing in the compartment (even on the anode current collector) In this case, the electrochemical reactor can be operated efficiently and easily without interruption, and the exhaust gas can be purified.

  Moreover, the exhaust gas purification system which processes the particulate matter contained in exhaust gas can be provided, without applying a voltage to an electrode during a process. That is, it is possible to provide an electrochemical exhaust gas purification system that is self-contained and does not require an external power source or the like and that can continuously remove particulate matter.

It is a longitudinal section conceptual diagram showing an example of the basic configuration of the exhaust gas purification system of the present invention. It is a perspective view which shows an example of the basic composition of the exhaust gas purification system of this invention. It is sectional drawing of an example of the electrostatic precipitator used for this invention. It is a figure which shows an example of the vehicle-mounted arrangement | positioning of the exhaust gas purification system of this invention. It is a schematic longitudinal cross-sectional view which shows an example of the basic composition of the electrochemical reactor used for the exhaust gas purification system of this invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the technical idea thereof.

[Exhaust gas purification system]
FIG. 1 is a longitudinal sectional conceptual diagram showing an example of a basic configuration of an exhaust gas purification system of the present invention. FIG. 2 is a perspective view showing an example of the basic configuration of the exhaust gas purification system of the present invention.

<Cyclone collector>
The exhaust gas purification system of the present invention includes a cyclone collector 2 that collects particulate matter contained in the exhaust gas H discharged from the internal combustion engine E. Exhaust gas H discharged from the internal combustion engine E is sent to the cyclone collector 2 through the intake pipe 1. Then, the particulate matter in the exhaust gas H collected by the cyclone collector 2 is supplied to the electrochemical reactor 14 in the compartment 5 attached to the cyclone collector 2, and the particulate matter is supplied. The material is removed electrochemically. The exhaust gas H from which the particulate matter has been removed electrochemically is released into the atmosphere through the exhaust pipe 11.

In the present invention, a partition plate 3 is provided between the cyclone collector 2 and the compartment 5, and is collected by the cyclone collector 2 on the cyclone collector 2 side of the partition plate 3. It is preferable that the particulate matter once stored can be stored. If the anode 111 of the electrochemical reactor 14 is directly installed in the lower part of the cyclone collector 2 itself, the electrochemical reactor 14 (the anode 111) is likely to be damaged. However, the cyclone collector 2 and the compartment 5 are easily damaged. If the partition plate 3 is provided between the two, damage can be prevented. In order to obtain high power generation characteristics in this solid oxide fuel cell, it is important that the generated CO and CO ₂ stay in the anode 111 for a long time, and air from outside the system, that is, leakage of oxygen. It is necessary to reduce dust as much as possible. Therefore, if the partition plate 3 is provided between the cyclone collector 2 and the compartment 5, the sealing performance is improved, so that high power generation efficiency is obtained.

  In the exhaust gas purification system of the present invention, the reaction proceeds even if the solid carbon 102 is not directly supported or deposited on the anode 111 or the anode material 111b as in the known techniques described in Patent Documents 1 to 5, It is only necessary to store on the cyclone collector 2 side of the plate 3 and place them intermittently on the anode 111 of the electrochemical reactor 14. That is, even if the solid carbon 102 is stacked with a certain thickness on the anode material 111b or the anode current collector 111a, the reaction proceeds in the entire thickness direction (because the solid carbon 102 can be processed). For the first time, it became possible to use the method of “cyclone collection” followed by “supply to the anode 111”.

  In the electrochemical reactor 14 in the exhaust gas purification system of the present invention, the reaction proceeds without directly supporting or depositing the solid carbon 102 on the anode 111 (anode material 111b), and only the electrochemical removal of the solid carbon 102 is performed. In addition, the configuration and principle (of the electrochemical reactor 14) that can generate power using the solid carbon 102 as fuel will be described later.

With regard to the “supply to the anode 111 collectively”, a control unit (not shown) for determining the supply timing to supply to the electrochemical reactor 14 from the cyclone collector 2 side of the partition plate 3 is provided. It is preferable that an appropriate amount of the solid carbon 102 can be supplied to the anode 111 side of the electrochemical reactor 14. The criteria for determining the timing of supplying the particulate matter once stored on the side of the cyclone collector 2 with respect to the partition plate 3 to the electrochemical reactor 14 are not particularly limited, and the operation elapsed time of the internal combustion engine, the cyclone trapping of the partition plate 3 are not limited. The weight or height of the particulate matter accumulated on the collector 2 side (mounted on the partition plate 3 in FIGS. 1 and 2), the generated gas (CO, CO ₂ ) concentration, and the like can be mentioned. Moreover, the system which always supplies at fixed time may be used.

  In particular, a partition plate 3 is provided between the cyclone collector 2 and the compartment 5, and when the collected particulate matter reaches a certain weight, the partition plate 3 opens to collect the cyclone. It is easy to control that the particulate matter is supplied from the bottom of the vessel 2 to the anode 111 of the electrochemical reactor 14, and a steady operation of the electrochemical reactor 14 is possible. This is preferable.

  Supply to the electrochemical reactor 14 in the compartment 5 is made by opening the partition plate 3. Here, “opening” is not particularly limited as long as it is an operation in which particulate matter is supplied. Specifically, for example, the partition plate 3 is removed, tilted, or like an aperture of a camera. Open to the center, open in a double door near the center, and rotate.

  The structure, type, size and the like of the cyclone collector 2 are not particularly limited as long as the particulate matter contained in the exhaust gas H discharged from the internal combustion engine can be easily collected. In FIG. 1 and FIG. 2, the particulate matter falls on the wall surface of the cyclone collector 2 while swirling, and the gas in which the particulate matter is collected is placed on the central axis portion of the cyclone collector 2. It comes to be leaked toward. The exhaust gas H that has flowed out is exhausted through the exhaust pipe 11.

  An oxygen supply pipe 13 for supplying a gas containing oxygen such as air is disposed on the cathode 131 located on the lower surface of the electrochemical reactor 14. The oxygen supply pipe 13 can supply an oxygen-containing gas such as air to the cathode 131 of the electrochemical reactor 14.

Further, on the anode 111 side of the electrochemical reactor 14 in the compartment 5, a carbon dioxide (CO ₂ ) discharge port 103 for discharging CO ₂ generated by the electrochemical reaction is installed.

  The materials such as the compartment 5, the partition plate 3, and the oxygen supply pipe 13 are not particularly limited as long as the materials have heat resistance and corrosion resistance. Preferably, iron, stainless steel, Inconel, Hastelloy, carbon molybdenum steel, carbon vanadium steel, chromium molybdenum steel, and the like can be given. In addition, the material, structure, etc. of each part which comprises the anode, cathode, electrolyte, etc. of the electrochemical reactor 14 are mentioned later.

  In aspect 1 of the present invention, the electrochemical reactor 14 is a solid oxide fuel cell using solid carbon 102 in a particulate material as fuel. Although the structure of the solid oxide fuel cell 14 will be described later, the solid carbon 102 in the particulate matter is reacted with carbon dioxide generated by power generation to be converted into carbon monoxide, and the carbon monoxide is oxidized. To generate electricity. In the aspect 1, electric power obtained from the solid oxide fuel cell 14 that is the electrochemical reactor 14 is obtained outside through the lead wire 15. Further, it is controlled by an external electronic circuit via a lead wire 15 (which may be different from an output lead wire).

  In aspect 2 of the present invention, the electrochemical reactor 14 is a solid oxide processing apparatus. By applying a voltage between the anode 111 and the cathode 131 of the solid oxide processing apparatus 14, oxygen ions are transferred to the anode 111, and on the anode 111, the oxygen ions and the solid carbon 102 in the particulate matter are Is reacted electrochemically to remove particulate matter. In the aspect 2, a voltage can be applied from the outside through the lead wire 15 between the anode 111 and the cathode 131 of the solid oxide processing apparatus 14 which is an electrochemical reactor. The voltage applied from the outside is controlled by an external electronic circuit via the lead wire 15.

<Electric dust collector>
Furthermore, in the exhaust gas purification system of the present invention, it is also preferable that an electric dust collector D as shown in FIG. 3 is provided between the cyclone collector 2 and the internal combustion engine E. By turning off the switch 19 of the electrostatic precipitator D, the particulate matter collected therein can be collectively transferred to the cyclone collector 2. Thereby, the direct collection by the cyclone collector 2 and the collection by the electric dust collector D can be used in combination. By combining the electric dust collector D, the collection efficiency of the particulate matter by the cyclone collector 2 can be increased, or can be selectively used depending on the kind of the particulate matter contained in the exhaust gas H.

  FIG. 3 is a cross-sectional view of an example of the electrostatic precipitator D according to the present invention. The electrostatic precipitator D is a substantially cylindrical body having openings at both end faces, and one end of the opening is connected to the internal combustion engine E and the other end is connected to the intake pipe 1. The exhaust gas Ha discharged from the internal combustion engine E is sent to the electric dust collector D by the combustion exhaust pressure of the internal combustion engine, and the exhaust gas Ha is electrically collected and discharged as exhaust gas Hb. As for the dust collecting mechanism, a general electric dust collecting mechanism by discharge is suitably used, and as shown in FIG. 3, it is composed of a discharge electrode 16 and a dust collecting electrode 17 in which the discharge electrode 16 is arranged in a cylindrical body. It is preferable to operate by an electric circuit such as a power source 18 and a switch 19.

<Example of arrangement>
FIG. 4 is an explanatory diagram showing an example when the exhaust gas purification system of the present invention is installed on a vehicle. In the case of an automobile C having a general front engine layout, as shown in FIG. 4, an exhaust gas purification system 100 is arranged behind the internal combustion engine E (the electric dust collector D is arranged if necessary). If it is an FR vehicle, it can be arranged in the center tunnel, and if it is an FF vehicle, it can be arranged in the engine room or immediately before the silencer. The layout itself is not particularly limited as long as the exhaust gas Hb exhausted from the exhaust gas purification system 100 is decompressed by a silencer through a muffler pipe or the like and releases the exhaust gas Hc into the atmosphere. Good.

  Furthermore, a conventional chemical catalyst can be used in combination. Moreover, as shown in FIG. 1, it is also preferable to provide a DPF (Diesel particulate filter) 4.

<Electrochemical reactor>
In the exhaust gas purification system of the present invention, as described above, the particulate matter collected by the cyclone collector 2 is supplied to the electrochemical reactor 14 in the attached compartment 5 and is electrochemically supplied. It is characterized by removing. The electrochemical reactor 14 in the present invention is a solid oxide fuel cell in the aspect 1, and is a solid oxide processing apparatus in the aspect 2.

  Hereinafter, the electrochemical reactor 14 according to the present invention will be described by taking the solid oxide fuel cell 14 of Embodiment 1 as an example.

  Even in the solid oxide processing apparatus 14 of the embodiment 2, the preferred materials (substances) and structures (forms) such as the anode 111, the cathode 131, and the electrolyte are the same as those of the solid oxide fuel cell 14 of the embodiment 1 described below. This is different from the solid oxide fuel cell 14 of Embodiment 1 in that oxygen ions are transferred to the anode 111 mainly by applying a voltage between the anode 111 and the cathode 131, and no power is generated. Only.

<Form of solid oxide fuel cell>
FIG. 5 is a schematic cross-sectional view showing the basic configuration of a preferred embodiment of the solid oxide fuel cell 14 used in the exhaust gas purification system of the present invention. FIG. 5 shows at least the compartment 5 in which the solid oxide fuel cell 14 is installed and the oxygen supply pipe 13 in addition to the solid oxide fuel cell 14. The solid oxide fuel cell 14 mainly includes an anode 111, a cathode 131, and an electrolyte 121 disposed between the anode 111 and the cathode 131. As shown in FIG. 5, the anode 111 further includes an anode material 111b and an anode current collector 111a. Further, as shown in FIG. 5, the cathode 131 includes a cathode material 131b and a cathode current collector 131a.

  A solid oxide fuel cell 14 is provided in the compartment 5, and the compartment 5 can store the solid carbon 102 in the particulate matter contained in the exhaust gas H exhausted from the internal combustion engine. Yes. Here, the compartment 5 is a space for storing the solid carbon 102 for power generation provided on the anode 111 side when viewed from the solid oxide fuel cell 14. The solid carbon 102 stored therein does not need to be in contact with the anode 111, but it is also preferable that at least a part of the solid carbon 102 is in contact with the anode 111. More specifically, it is not necessary for the solid carbon 102 to be in contact with the anode current collector 111a or the anode material 111b, but it is also preferable that a part of the solid carbon 102 is in contact with it. .

  Although not limited, for example, in FIG. 5, particulate matter (solid carbon 102) is stored in about 40% of the lower part of the compartment 5. Even during power generation, solid carbon 102 as fuel is added to the compartment 5 from the partition plate 3 adjacent to the cyclone collector 2, so that power generation can be continued.

It is preferable that oxygen contamination on the anode 111 side be reduced as much as possible from the viewpoint of power generation efficiency. In order to remove oxygen, it is also preferable to replace the inside of the compartment 5 with an inert gas such as nitrogen (N ₂ ) or carbon dioxide (CO ₂ ).

If there is solid carbon 102 in the compartment 5 and CO ₂ generated by power generation is present at 500 to 1000 ° C., for example, the CO generation reaction proceeds and power generation is continued by the solid oxide fuel cell 14. The present invention has been made on the basis of a new discovery of this surprising fact. Because of this phenomenon, the particulate matter contained in the exhaust gas H is collected by the cyclone collector 2, and the particulate matter is supplied to the solid oxide fuel cell 14 in the attached compartment 5. Thus, a system for purifying the exhaust gas H while generating electricity was completed.

Further, the solid oxide fuel cell 14 shown in FIG. 5 has a carbon dioxide (CO ₂ ) outlet 103 for discharging CO ₂ on the anode 111 side and an oxidant such as oxygen (O ₂ ) on the cathode 131 side. Is provided with an oxygen supply pipe 13.

  In addition to the basic configuration shown in FIG. 5, it is preferable that the tip of a power generation initiator introduction pipe (not shown) for supplying a power generation initiator at the start of power generation is disposed on the anode 111 side. The arrangement of the tip of the power generation initiator introduction pipe is not particularly limited as long as it is on the anode 111 side. Since the tip of the power generation initiator introduction pipe is arranged on the anode 111 side, the power generation initiator is supplied in the vicinity of the anode material 111b. As a result, the initial power generation characteristics are easily stabilized, and the electric power in the exhaust gas purification system is improved. The chemical reactor 14 is stably operated for the initial operation.

  The aspect 1 also has an electric circuit (not shown) for electrochemically injecting an oxygen source into the anode 111 in addition to the basic structure of the solid oxide fuel cell 14 shown in FIG. It is preferable. Also in the aspect 1, it is preferable that the oxygen source is electrochemically injected into the anode 111 at the start of the exhaust gas purification system, that is, at the start of power generation, from the viewpoint of stabilizing the initial power generation characteristics. The oxygen source is not particularly limited, and specific examples include air and oxygen.

The method for electrochemically injecting the oxygen source is not particularly limited. Specifically, for example, the Nernst potential of the battery cell is used between the anode 111 and the cathode 131, and the current density is 0.01 mA / It flows at a rate of cm ^{2 to 5} mA / cm ² , oxygen is taken in by the cathode 131 and becomes oxide ions (O ²⁻ ), and this O ²⁻ moves through the electrolyte 121 and reacts with the fuel at the anode 111 to give electrons. It is preferable to release and initiate the electrode reaction. If the oxygen source is not electrochemically injected into the anode 111 at the start of power generation, stable power generation cannot be obtained at the initial stage of power generation, and the exhaust gas purification system may not start stably.

<< Anode >>
The anode material 111b of the anode 111 includes a composite metal oxide. That is, the anode material 111b may include a composite metal oxide, or may include cermet. Here, “cermet” means a mixture of metal and metal oxide powder and sintered. The composite metal oxide or cermet is preferably porous. As the composite metal oxide or cermet, those generally used as the anode active material in the known solid oxide fuel cell 14 can be suitably used.

[Composite metal oxide]
As a composite metal oxide which is used as a component of the anode material 111b and also as a raw material of the cermet which is a component of the anode material 111b, it is generally used as an anode active material in the solid oxide fuel cell 14. If there is no particular limitation. From the viewpoint of reliably obtaining sufficient output characteristics, durability, etc. during power generation, stabilized zirconia (Y ₂ O ₃ —ZrO ₂ ) containing yttria (hereinafter abbreviated as “YSZ”); Gd , La, Y, Sm, Nd, Ca, Mg, Sr, Ba, Dy and Yb doped with at least one kind of CeO ₂ [Of these, CeO ₂ doped with Gd (hereinafter, Sg-doped CeO ₂ is preferred]; Sc ₂ O ₃ —ZrO ₂ (hereinafter abbreviated as “ScSZ”); Sm ₂ O ₃ —CeO ₂ (hereinafter “SDC”) Are abbreviated to be particularly preferable.

In the case of the _{YSZ, (the} content of Y 2 _{O 3)} ratio of Y 2 _{O 3,} it is preferred for Y ₂ O 3 -ZrO ₂ is 8-10 mol%. In addition, in the case of the GDC, (content of Gd) proportion of Gd is preferably 3 to 40 mol% based on doped CeO _2, more preferably 8 to 40 mol%, further 10 to 40 mol% Preferably, it is 15-40 mol%, and it is especially preferable. Furthermore, in the case of CeO ₂ doped with Sm, the ratio of Sm (content of Sm) is preferably 15 to 40 mol% with respect to doped CeO ₂ . Particularly preferable ceria-based solid solutions include Ce _0.8 Gd _0.2 O _2-δ (where δ represents the amount of oxygen deficiency), Ce _0.67 Gd _0.33 O _2-δ (wherein , Δ represents the amount of oxygen deficiency) and the like.

In addition, it is preferable to use a composite metal oxide having electrical conductivity from the viewpoint of obtaining sufficient output characteristics during power generation. The conductivity of the composite metal oxide is particularly preferably 0.01 to 10 Scm ⁻¹ at 1000 ° C.

[[cermet]]
From the viewpoint of more reliably obtaining excellent output characteristics as a battery, the anode material 111b is preferably cermet. The cermet is not particularly limited as long as it is generally used as the anode active material in the solid oxide fuel cell 14, but is selected from the group consisting of Ni, Pt, Au, Cu, Fe, W and Ta. A cermet of at least one metal and a complex metal oxide (particularly the complex metal oxide) is preferred. From the point of ensuring sufficient output characteristics during power generation, etc., cermets of nickel and composite metal oxides are preferred, and in particular, cermets of nickel and the above composite metal oxides are preferred. It is mentioned as a thing.

  Particularly preferably, in terms of output characteristics, cermet of nickel and YSZ (hereinafter abbreviated as “Ni / YSZ”), cermet of nickel and GDC (hereinafter abbreviated as “Ni / GDC”), nickel, It is a cermet with ScSZ (hereinafter abbreviated as “Ni / ScSZ”) or a cermet with nickel and SDC (hereinafter abbreviated as “Ni / SDC”).

Moreover, it is preferable from the point of ensuring electronic conductivity that the volume fraction V1 of the metal in a cermet and the volume fraction V2 of a composite metal oxide satisfy | fill the conditions represented by a following formula.
0.2 ≦ [V1 / (V1 + V2)] ≦ 0.8

  Here, if [V1 / (V1 + V2)] is less than 0.2, sufficient electron conductivity in the anode material 111b cannot be secured, and the output characteristics of the solid oxide fuel cell 14 may be insufficient. is there. If [V1 / (V1 + V2)] exceeds 0.8, the ion conductivity in the anode material 111b cannot be sufficiently secured, and the output characteristics of the solid oxide fuel cell 14 may be insufficient. . [V1 / (V1 + V2)] is preferably 0.2 to 0.8, and preferably 0.3 to 0.7 from the viewpoint of sufficiently ensuring both electron conductivity and ion conductivity in the anode material 111b. Particularly preferred is 0.4 to 0.6.

  Specifically, in Ni / YSZ, Ni / GDC, Ni / ScSZ, or Ni / SDC, the value of Ni / (such composite metal oxide + Ni) falls within the above range as the volume fraction ratio. Is preferred.

[[Composite metal oxide with electrical conductivity]]
Here, when the anode material 111b is a material containing metal particles or alloy particles such as cermet, the metal in the anode 111 causes carbide and carbon whiskers, and causes long-term electrode deterioration. There is a case. That is, when carbon dissolved in the metal precipitates and grows, the metal particles are dropped from the frame structure of the electrode, which may cause deterioration of the electrode. Moreover, the volume expansion / contraction of the metal particles during the redox cycle may cause electrode deterioration. Therefore, it is also preferable to use a composite metal oxide having electrical conductivity in place of the cermet as the anode material 111b.

In place of the cermet containing metal particles or alloy particles that cause electrode deterioration, the composite metal oxide having electrical conductivity is used for at least one anode material of the anode material 111b, thereby causing the electrode deterioration factor. Is eliminated, deterioration of the anode 111 is suppressed during the operation of the RDCFC, redox cycle characteristics are improved, and high output can be stably maintained. It is preferable that the anode material 111b includes a composite metal oxide having electrical conductivity. Here, “having electrical conductivity” means that the electrical conductivity is 10 ⁻⁴ Scm ⁻¹ or more at the operating temperature.

  Here, a metal may be contained within a range in which the above-described electrode deterioration does not occur, and the present invention does not exclude the inclusion of a small amount of “metal particles or alloy particles” from the composition of the anode material 111b. . The total amount of “metal particles or alloy particles” contained in the anode material 111b is preferably 10% by mass or less, more preferably 5% by mass or less, and particularly preferably 2% by mass or less, including both metal particles and alloy particles. More preferably not.

The electric conductivity of the above-mentioned “complex metal oxide having electric conductivity” is preferably 10 ⁻² Scm ⁻¹ or more, particularly preferably 10 ⁻¹ Scm ⁻¹ or more, at the operating temperature. Here, “electric conduction” means electric conduction consisting of at least one of electron conduction, hole conduction, oxide ion conduction and proton conduction, that is, one or more of them are combined. Means electrical conduction. If the electrical conductivity is too low, sufficient output characteristics may not be obtained.

  The anode 111 preferably contains neither metal particles nor alloy particles, or contains metal particles or alloy particles up to a range in which a three-dimensional network is not formed. The “three-dimensional network” refers to a state in which electrical conduction is possible through the anode 111 in the thickness direction. If a three-dimensional network is formed by metal particles or alloy particles, the anode 111 may deteriorate as a result of repeated expansion and contraction of the anode material 111b due to repeated oxidation and reduction.

  Further, the composite metal oxide having electrical conductivity used for the anode material 111b itself forms a three-dimensional network, that is, the three-dimensional network capable of conducting electrons by the composite metal oxide itself. Is preferable in that good electrical conductivity is realized and as a result, sufficient output characteristics can be obtained.

  It is preferable that at least one of the complex metal oxides having electrical conductivity used for the anode material 111b is composed of a complex metal oxide having a perovskite crystal structure, a pyrochlore crystal structure, or a fluorite crystal structure. .

The composite metal oxide having a perovskite crystal structure refers to a composite metal oxide having a so-called perovskite crystal structure, and a composite metal oxide represented by the following general formula (G) is preferable.
A _{1 ± a} B _{1 ± b} O _3-δ (G)
[In the composition formula (G), A represents La, Sr, Ca, Y, Ba, Pr, Ce, K, Na, Sm, Pb, Nd, Gd, Bi, Ag, Cs, Rb, Tl, Cd, Eu. , Mg, Dy, Li, and Ho, B represents Co, Cr, Mn, Ni, Ce, Gd, Al, Ti, Zr, Sc, Mg, Ga, Cu, Fe Yb, Y, Nb, I, Ni, Sr, Bi, In, Ca, Sn, Ta, W, Th, U, Hf, Mo, Lu, Tm, Tb, Dy, Ho, Os, Rh, Ag, Tr , Sb, Zn, Pa, In, Re, and Er, at least one selected from the group consisting of 0 ≦ a ≦ 0.2 and 0 ≦ b ≦ 0.2, and δ is the amount of oxygen deficiency. ]

Of these, substances based on LaMnO ₃ , LaCoO ₃ , LaCrO _{3 and the} like are more preferable. For example, (LaSr) MnO ₃ -based composite metal oxide (in the present invention, this is abbreviated as “LSM”), ( LaSr) CoO ₃ -based composite metal oxide (in the present invention, this is abbreviated as “LSC”) is particularly preferable.

  Moreover, in compositional formula (G), it is preferable for B to contain 50 mol% or more of Mn with respect to the whole B in order to exhibit the said effect more. Further, in the composition formula (G), B contains 50 mol% or more of Co with respect to the entire B, or B contains Co and Fe in total of 50 with respect to the entire B. It is preferable for the content to be at least mol% in order to achieve the above effects.

Other composite metal oxides having a perovskite crystal structure are represented by the general formula A (B _1-x M _x ) _{1 ± a} O _3-δ [where 0 ≦ x ≦ 0.8, 0 ≦ a ≦ 0. .2], A is at least one selected from divalent cations such as Ba, Sr, and Ca, B is at least one selected from tetravalent cations such as Ce, Zr, and Ti, and M Is at least one selected from trivalent rare earth, Y, Sc, In, Yb, Nd, Gd, Al, Ga and the like.

For example, Ba (Ce _1-x Gd _x ) _{1 ± a} O ₃ [where 0 ≦ x ≦ 0.8, 0 ≦ a ≦ 0.2], Ca (Al _1-x Ti _x ) _{1 ± a} O ₃ [wherein, 0 ≦ x ≦ 0.8,0 is _{≦ a ≦ 0.2], Sr (} Ce 1-x Yb x) in _{1 ±} a _{O 3} (wherein, 0 ≦ x ≦ 0. 8, 0 ≦ a ≦ 0.2), Sr (Zr _1−x Y _x ) _{1 ± a} O ₃ (where 0 ≦ x ≦ 0.8, 0 ≦ a ≦ 0.2), Those represented by Sr (Zr _1-x Sc _x ) _{1 ± a} O ₃ (where 0 ≦ x ≦ 0.8, 0 ≦ a ≦ 0.2) are also preferred. Specifically, BaCe _0.9 Gd _0.1 O ₃ , CaAl _0.7 Ti _0.3 O ₃ , SrCe _0.95 Yb _0.05 O ₃ , SrZr _0.95 Y _0.05 O ₃ , SrZr _0.9 Sc _0.1 O _{3 and the} like.

_{Formula, La 1-x Sr x Ga} 1-y-z Mg y M z O 3 [ wherein, M represents, Co, Fe, indicates any one or more elements of Ni or Cu, x = 0. It is the range of 05-0.3, y = 0-0.29, z = 0.01-0.3, y + z = 0.025-0.3. The lanthanum gallate represented by the formula is also preferable. Specific examples include La _0.8 Sr _0.2 Ga _0.8 Mg _0.15 Co _0.05 O _3-δ (where δ represents the amount of oxygen deficiency).

Specific examples of the composite metal oxide having preferable electrical conductivity include La _0.8 Sr _0.2 MnO ₃ , La _0.85 Sr _0.15 MnO ₃ , and La _0.95 Sr _0.05. La _1-b Sr _b MnO [b is 0 ≦ b ≦ 0.5], such as MnO ₃ ; La _0.8 Sr _0.2 CoO ₃ , La _0.85 Sr _0.15 CoO ₃ La _1-d Sr _d MnO ₃ [d is 0 ≦ d ≦ 0.5], such as La _0.95 Sr _0.05 CoO ₃ ; La _0.6 Sr _0.4 Fe _{0. 8 Co 0.2 O 3, La 0.6} Sr 0.4 Fe 0.2 Co 0.8 La 1-e Sr of _{O 3, e Fe f Co 1-f O} 3 [e is 0 ≦ e ≦ 0 .5, f is a compound represented by 0 ≦ f ≦ 1]; La _0.75 Sr _{0. 2} Cr _0.5 Mn _0.5 O _{3 and} other La _1-g Sr _g Cr _1-h Mn _h O ₃ [g is 0 ≦ g ≦ 0.5, h is 0 ≦ h ≦ 1] And the like.

The composite metal oxide having a pyrochlore crystal structure refers to a composite metal oxide having a so-called pyrochlore crystal structure, Ln ₂ ((Zr _1−x Ti _x ) ₂ ) _{1 ± a} O ₇ (wherein Ln represents one or more elements selected from the group consisting of Sc, Y, La and other lanthanoids, and 0 ≦ x ≦ 0.5 and 0 ≦ a ≦ 0.2) are preferred. . Specifically, for example, Gd ₂ ((Zr _1-x Ti _x ) ₂ ) _{1 ± a} O ₇ (where 0 ≦ x ≦ 0.5, 0 ≦ a ≦ 0.2), Y ₂ ( (Zr _1-x Ti _x ) ₂ ) _{1 ± a} O ₇ (where 0 ≦ x ≦ 0.5, 0 ≦ a ≦ 0.2).

The composite metal oxide having a fluorite-type crystal structure refers to a composite metal oxide having a so-called fluorite-type crystal structure. Among them, a ceria-based composite metal oxide is preferable, and Ce _1-x M _x O ₂ (wherein M is selected from the group consisting of Gd, La, Y, Sc, Sm, Pr, Nd, Ca, Mg, Sr, Ba, Dy, Yb, Tb and other divalent or trivalent lanthanoids) 1 or more elements, and 0 ≦ x ≦ 0.5). Particularly preferred ceria-based composite metal oxides include Ce _0.8 Gd _0.2 O _2-δ (where δ represents the amount of oxygen deficiency).

  As the composite metal oxide having electrical conductivity used for the anode material 111b, the composite metal oxide having a perovskite crystal structure has high electrical conductivity without containing metal particles or alloy particles, It is particularly preferable in that the effect of the present invention is further exhibited.

When the anode material 111b is a composite material composed of two or more kinds of anode materials, the anode material other than the above is preferably also a composite metal oxide. Furthermore, in the anode 111, two or more kinds of composite metal oxides having at least one of electron conductivity and hole conductivity, and composite metal oxides having at least one of oxide ion conductivity and proton conductivity. The anode material is preferably contained. Here, “having at least one of electron conductivity and hole conductivity” means that the combined electric conductivity is 10 ⁻⁴ Scm ⁻¹ or more, and “at least oxide ion conductivity. "Having either proton conductivity or proton conductivity" means that the combined electrical conductivity is 10 ⁻⁴ Scm ⁻¹ or more.

Preferred anode material 111b in the present invention is that LSM / GDC, which is a composite material of LSM and GDC, LSC alone, and a composite of LSC and GDC in that it has both relatively high electronic conductivity and oxide ion conductivity. Examples thereof include LSC / GDC which is a material. In addition, a composite material of LSM and SrCe _1-i Yb _i O ₃ (i is 0 ≦ i ≦ 1) (hereinafter abbreviated as “SCYb”) in that it has both electron conductivity and proton conductivity. And LSC / SCYb, which is a composite material of LSC and SCYb. Further, in terms of having proton conductivity in addition to electron conductivity and oxide ion conductivity, (LSM or LSC), a composite material of GDC and SCYb (LSM or LSC) / GDC / SCYb, and the like can be given. .

[Film thickness]
The thickness of the anode material 111b is not particularly limited, but is usually 10 μm to 5 mm, preferably 20 μm to 1 mm, more preferably 30 μm to 700 μm, still more preferably 40 μm to 400 μm, and most preferably 50 μm to 150 μm. The film thickness may be measured by a stylus type surface roughness meter or cross-sectional observation by SEM.

  Note that the optimum thickness of the anode 111 (fuel electrode) mentioned here varies depending on the porosity. That is, since the porosity affects the ease of gas diffusion to the anode 111 and the ease of movement of the generated carbon monoxide (CO) gas to the effective reaction site, the thickness changes as the porosity changes. Optimum conditions may vary. Therefore, it is preferable to determine the thickness of the anode 111 as appropriate in accordance with the obtained porosity of the anode 111.

[Power generation initiator]
Although the electrochemical reactor 14 is indispensable for the exhaust gas purification system of the present invention, the electrochemical reactor 14 may generate power regardless of whether or not electricity generated from the electrochemical reactor 14 is used. Therefore, in this case, starting the operation of the electrochemical reactor 14 may be referred to as “starting the power generation of the electrochemical reactor 14”. In the exhaust gas purification system of the present invention, the operation of the electrochemical reactor is started by supplying “power generation initiator” which is carbon monoxide or carbon dioxide to the solid carbon in the particulate matter supplied as fuel. It is preferable. When using the exhaust gas purification system of the present invention, it is preferable that the power generation is started by supplying a power generation initiator to the anode 111, that is, the operation of the exhaust gas purification system is started because the initial characteristics are easily stabilized. . Here, the “power generation initiator” refers to carbon monoxide or carbon dioxide. In the power generation initiator introduction step, the power generation initiator is supplied, and the power generation initiator that is carbon monoxide or carbon dioxide is brought into contact with the solid carbon 102 existing in the compartment 5.

  The means for introducing the power generation initiator is not particularly limited. If the tip of the power generation initiator introduction pipe is disposed at a position where the power generation initiator reaches the anode 111, it is disposed at any position on the anode 111 side. It may be.

[Anode mechanism, structure, physical properties, etc.]
In operation of the exhaust gas purification system of the present invention, in the first aspect, during power generation, the solid carbon 102 supplied from the cyclone collector 2 to the compartment 5 is used, and at least the reaction formulas (1) and (2) described later. ) To generate electrons. At the same time, the cathode 131 donates electrons to the oxidizing gas and injects ionized oxide ions (O ²⁻ ) into the electrolyte 121.

The size of the electrochemical reactor 14 in the present invention (the solid oxide fuel cell in aspect 1 of the present invention and the solid oxide processing apparatus in aspect 2 of the present invention) is not particularly limited, but is 1 cm ^{3 to} 500 m ^3. it is ^preferably, and particularly preferably 1000cm ³ ~50000cm 3.

  The output during power generation of the solid oxide fuel cell 14 in Embodiment 1 of the present invention is not particularly limited, but is preferably 0.001 kW to 500 kW, particularly preferably 0.01 kW to 100 kW, and 0.01 kW to 10 kW. More preferably. The output can be generated in the case of the size.

  If the constituent material of the anode current collector 111a of the anode 111 has electronic conductivity and is chemically and physically stable in the operating temperature region of the solid oxide fuel cell 14, its shape and constituent material Is not particularly limited, and those similar to those provided in the known solid oxide fuel cell 14 can be used. Those which are chemically and physically stable at 600 ° C. to 1200 ° C. are preferred.

  The anode current collector 111a also functions as a separator disposed between the unit cells when a plurality of electrochemical reactors 14 are stacked.

  The anode 111 has a gas supply port (not shown) and a discharge port (not shown), and an internal gas flow path (not shown) connected to the supply port and the discharge port. It may be provided. The electrochemical reactor 14 in the present invention is connected to a gas supply port and a discharge port, and these supply port and a discharge port, although the kind of fuel, a method of use, and a principle are different from a general known fuel cell. As a mechanical external structure such as a gas internal flow path, the same structure as that of a generally known fuel cell can be used.

  In the electrochemical reactor 14 according to the present invention, it is preferable that substantially no carrier gas for releasing the reaction product gas to the outside is introduced into the anode 111. As will be described later, it is preferable that the carrier gas is not substantially introduced because the reaction represented by the reaction formula (1) occurs more efficiently at the anode 111. This also makes the device configuration much more compact.

<< Cathode >>
During power generation, the cathode 131 is supplied with “a gas containing an oxidant (for example, oxygen)” (for example, air), and the cathode material 131b serves as a reaction field in which a reduction reaction of the oxidant proceeds. The composition and shape of the cathode material 131b are not particularly limited, and those similar to those generally used for the cathode 131 provided in the known solid oxide fuel cell 14 can be used. For example, a material composed of (LaSr) MnO ₃ -based or (LaSr) CoO ₃ -based composite metal oxide can be preferably used. Particularly preferable examples include La _0.85 Sr _0.15 MnO ₃ .

  The configuration of the cathode current collector 131a of the cathode 131 is the same as that of the anode current collector 111a of the anode 111 described above, and the constituent material and shape are not particularly limited, and a known solid oxide fuel cell 14 is used. Similar to those provided can be used. The cathode current collector 131a is formed with a gas flow path (not shown) for supplying a gas containing an oxidizing agent such as air to the cathode material 131b. Further, the cathode current collector 131a also functions as a separator disposed between the unit cells when a plurality of the solid oxide fuel cells 14 are stacked.

<< Electrolyte >>
The electrolyte 121 includes an ion conductive solid oxide. The electrolyte 121 is not only a moving medium for oxide ions (O ²⁻ ), but also a partition wall for preventing a reducing agent (the solid carbon 102 described above) and a gas (for example, air) containing an oxidizing agent from being in direct contact with each other. It functions and has a gas impermeable dense structure. The constituent material of the electrolyte 121 is not particularly limited, and a material used for a known solid oxide fuel cell 14 can be used. However, the conductivity of oxide ions is high, and an oxidizing atmosphere on the cathode 131 side is used. It is preferable to use a material that is chemically stable and resistant to thermal shock under conditions up to the reducing atmosphere on the anode 111 side.

Examples of materials that satisfy such requirements include yttria stabilized zirconia (YSZ),
Preferred examples include stabilized zirconia such as scandia-stabilized zirconia (ScSZ); lanthanum gallate; ceria-based solid solution.

Stabilized zirconia is not particularly limited, but the following general formula (ZrO ₂ ) _1-x (M ₂ O ₃ ) _x
[Wherein M represents one or more elements selected from the group consisting of Y, Sc, Sm, Al, Nd, Gd, Yb and Ce. However, here, when M is Ce, it is CeO ₂ instead of M ₂ O ₃ . Or the following general formula (ZrO ₂ ) _1-x (MO) _x
In the formula, M is preferably a solid solution in which x is 0 <x ≦ 0.3 in M represents one or more elements selected from the group consisting of Ca and Mg. Particularly preferable examples include (ZrO ₂ ) _1-x (Y ₂ O ₃ ) _x (where 0 <x ≦ 0.3), and more preferably 0.08 ≦ x ≦ 0.1. More preferable examples include (ZrO ₂ ) _0.92 (Y ₂ O ₃ ) _0.08 .

  For example, the expression “in the formula, A represents one or more elements selected from the group consisting of Q, R and T” is a solid solution in which A is Q and a solid solution in which A is R. In addition, the solid solution having Q and R simultaneously at the crystal site as A is also shown. The same applies hereinafter.

Although lanthanum gallate is not particularly limited, general _formula, La in _{1-x Sr x Ga 1-} y-z Mg y A z O 3 ( wherein, A is Co, Fe, any one or more of Ni or Cu Element is represented by x = 0.05 to 0.3, y = 0 to 0.29, z = 0.01 to 0.3, y + z = 0.025 to 0.3). A solid solution is preferred. Specific examples include La _0.8 Sr _0.2 Ga _0.8 Mg _0.15 Co _0.05 O _3-δ (where δ represents the amount of oxygen deficiency).

The ceria-based solid solution is not particularly limited, but Ce _1-x M _x O ₂ (wherein M is Gd, La, Y, Sc, Sm, Al, Pr, Nd, Ca, Mg, Sr, Ba, Dy, A solid solution in which x is 0 <x ≦ 0.5 in Yb, Tb, and one or more elements selected from the group consisting of other divalent or trivalent lanthanoids) is preferable. Among them, Ce _1-x Gd _x O ₂ where M is Gd (where 0 <x ≦ 0.5), or Ce _1-x Sm _x O ₂ where M is Sm (where 0 <x ≦ 0.5) is more preferable, and in any formula, 0.03 ≦ x ≦ 0.4 is particularly preferable, 0.08 ≦ x ≦ 0.4 is further preferable, and 0.1 ≦ x ≦ 0.4. 0.4 is most preferred. Particularly preferable ceria-based solid solutions include Ce _0.8 Gd _0.2 O _2-δ (where δ represents the amount of oxygen deficiency), Ce _0.67 Gd _0.33 O _2-δ (wherein , Δ represents an oxygen deficiency amount), Ce _0.9 Gd _0.1 O _2-δ (where δ represents an oxygen deficiency amount), and the like. In particular, it is preferable to use GDC as the material of the electrolyte 121 because the power density can be sufficiently increased even when the temperature during power generation is 750 ° C. or lower.

Moreover, from the viewpoint of obtaining sufficient output characteristics during operation of the exhaust gas purification system, the conductivity of the composite metal oxide is preferably 0.01 to 10 Scm ⁻¹ at 1000 ° C.

<Method for producing electrochemical reactor>
The manufacturing method of the electrochemical reactor 14 in this invention is not specifically limited, The well-known thin film manufacturing technique etc. which are applied to manufacture of a well-known solid oxide fuel cell can be used. For example, a squeegee method, a screen printing method, a vacuum deposition method, a sputtering method, a PVD method such as an ion plating method, a CVD method such as a thermal CVD method, a plasma CVD method, and a laser CVD method, a thermal spraying method, and the like.

  For example, as a method of forming the electrolyte 121, for example, a sheet forming and sintering method which is a known ceramic process can be exemplified. More specifically, the slurry obtained by mixing the raw material and the solvent is extended into a sheet shape, dried, and then shaped and fired as necessary using a cutter knife or the like. You may mix | blend well-known additives, such as a binder, a plasticizer, a dispersing agent, with a slurry as needed. Conditions such as molding and firing can be appropriately set according to the composition of the raw material. Further, for example, the electrolyte 121 layer can be formed on the anode 111 or the cathode 131 by a thin film forming method such as the PVD method, the CVD method, or the thermal spraying method described above.

<Driving method>
In the operation method of the exhaust gas purification system of the present invention, if necessary, after the step of supplying the power generation initiator such as carbon monoxide to the solid carbon 102 of the compartment 5 to start the cell reaction, air or the like is applied to the cathode 131. There is no particular limitation as long as the method includes at least a step of supplying a gas containing an oxidizing agent and generating electricity (removing the solid carbon 102) using the solid carbon 102 supplied from the cyclone collector 2 as a reducing agent. Usually, as long as the power generation initiator is introduced to start the cell reaction and the solid carbon 102 is continuously supplied from the cyclone collector 2, continuous operation is possible.

  The method for introducing the power generation initiator is not particularly limited, and an extremely small amount of carbon monoxide or carbon dioxide may be instantaneously flowed to the solid carbon 102 in the compartment 5. The inflow amount of the reaction initiator is not particularly limited as long as it is sufficient to start the battery reaction.

  Solid carbon 102 refers to carbon containing carbon, and “carbon” refers to simple carbon such as amorphous carbon and graphite. The solid carbon 102 is not particularly limited as long as it is contained in the particulate matter contained in the exhaust gas H discharged from the internal combustion engine.

In the power generation method of the solid oxide fuel cell 14 according to the first aspect of the exhaust gas purification system of the present invention, immediately after the start of power generation, the operation is performed while increasing the current density from its initial value, so that stable power generation and exhaust gas purification are possible. Preferred for. It is particularly preferable to gradually increase the current density immediately after the start of power generation. “Slowly increasing the current density” usually means increasing at a rate of 0.008 mA / cm ² to ² mA / cm ² per minute, and particularly preferably 0.016 mA / cm ^{2 to 1} mA / min per minute. cm ² . Outside this range, the initial power generation characteristics may not be stable.

  As mentioned above, although preferred embodiment of the electrochemical reactor 14 in this invention was described, this invention is not limited to the said embodiment.

In the first aspect of the present invention, the solid carbon 102 that has moved into the compartment 5 is reacted with carbon dioxide generated by power generation to be converted into carbon monoxide, and power is generated by oxidizing the carbon monoxide. In particular, at the time of power generation, the anode 111 generates power using at least the following reaction formulas (1) and (2).
CO ₂ + C → 2CO (1)
CO + O ²⁻ → CO ₂ + 2e ⁻ (2)

  By using the reaction formula (1), the solid carbon 102 supplied in the vicinity of the anode 111 is converted to gaseous CO and consumed as fuel, so that the influence of the location of the solid carbon 102 during power generation is extremely low. It becomes possible to make it smaller. That is, in the known solid oxide fuel cell 14, the electrode reaction generally closer to the surface of the electrolyte 121 has a greater contribution to power generation, so the solid carbon 102 distributed far from the surface of the electrolyte 121 is consumed. It is hard to be done. Therefore, in the present invention, a higher fuel utilization rate is obtained compared to the case where the reaction shown in the reaction formula (1) does not occur, and power generation is possible even when the solid carbon 102 is supplied at a position away from the anode 111. become.

  As in the case of “solid carbon stacked on the anode 111”, even if the solid carbon 102 exists at a position away from the anode 111, power generation and removal of the solid carbon 102 are possible. The particulate matter collected by the vessel 2 is temporarily held on the side partitioned by the partition plate 3, and intermittently supplied to the compartment 5 of the attached electrochemical reactor 14 to perform electrochemical It is possible to easily and continuously purify the exhaust gas H, which is to be removed.

In addition, since the CO oxidation reaction according to the reaction formula (2) has a higher reaction rate than the oxidation reaction of the solid carbon 102 according to the following reaction formula (3) or the reaction formula (4), a high output density can be obtained. In order to cause the reaction formula (2) to dominate, for example, the reaction product gas is not discharged outside the anode 111 beyond the pressure increase due to the reaction product gas, and the reaction formula (1) or the reaction formula (3) is used. Examples include increasing the time during which the produced carbon monoxide (CO) stays in the anode 111 and suppressing consumption due to oxidation of carbon monoxide (CO) caused by oxygen flowing from outside the system.
C + O ²⁻ → CO + 2e ⁻ (3)
C + 2O ²⁻ → CO ₂ + 4e ⁻ (4)

  In the present invention, it is preferable that 50 mol% or more of carbon monoxide (CO) consumed in the reaction formula (2) is generated in the reaction formula (1). That is, it is preferable that 50 mol% or more of carbon monoxide consumed during power generation is carbon monoxide generated by the reaction between the solid carbon 102 and carbon dioxide. Especially preferably, it is 60 mol% or more, More preferably, it is 70 mol% or more.

  In the present invention, it is preferable that 50% or more of the amount of charge transfer is due to oxidation of carbon monoxide obtained by the reaction between the solid carbon 102 and carbon dioxide.

  As means for predominantly starting the reaction formula (2), it is caused by extending the residence time of CO produced in the reaction formula (1) or the reaction formula (3) in the anode 111 or by oxygen flowing from outside the system. In order to suppress consumption due to oxidation of CO, for example, blocking inflow of oxygen can be mentioned. When a carrier gas is passed through the anode 111 as in a conventional method, the reaction formula (2) hardly occurs.

In order to cause the reaction represented by the reaction formula (1) in the anode 111, it is important to retain the CO ₂ produced in the electrode reaction (2) and / or (4) for a long time in the anode 111. It is preferable to eliminate the introduction of carrier gas during power generation. In order to eliminate the introduction of the carrier gas, it is preferable to reduce the leakage of air, that is, oxygen from outside the system as much as possible by improving the sealing performance and preventing the voltage drop due to the increase of the oxygen partial pressure.

  The gas containing the oxidant supplied to the cathode 131 is preferably air from the viewpoint of availability. From the same viewpoint, the oxidizing agent is preferably oxygen. In addition, from the viewpoint of improving the charge transfer amount and output density of the solid oxide fuel cell 14 during power generation in aspect 1, a carrier gas for releasing the reaction product gas in the anode 111 to the outside is supplied to the anode 111. Preferably not.

  The temperature during operation of the exhaust gas purification system of the present invention is preferably 400 to 1000 ° C, more preferably 450 to 900 ° C, and particularly preferably 500 to 750 ° C. If the temperature is too low, the reaction formula (1) is difficult to proceed, and the resistance of the cell (electrode and electrolyte) increases, which may reduce the output density. On the other hand, if it is too high, the cell and peripheral members may be deteriorated quickly.

In the aspect 1 of the present invention, the power density can be 50 (mW / cm ² ) or more at a temperature of 750 ° C. or lower during power generation. In addition, the solid oxide fuel cell 14 in which the composition, structure, setting, and the like are adjusted so that the power density is 50 (mW / cm ² ) or more is preferable. In particular, by using GDC as the electrolyte 121, the power density can be 50 (mW / cm ² ) or higher even when the temperature during power generation is 750 ° C. or lower.

Further, in aspect 1 of the present invention, the fuel utilization efficiency when generating power at a current density of 9.3 mA / cm ² can be 60% or more. In addition, the solid oxide fuel cell 14 whose composition, structure, setting, and the like are adjusted so that the fuel utilization efficiency is 60% or more is preferable. Here, the “fuel use efficiency” is the ratio of the consumed carbon amount calculated from the charge transfer amount assuming the reaction formula (4) with respect to the carbon in the solid carbon 102 supplied in the vicinity of the anode material 111b.

Moreover, in aspect 1 of this invention, the fuel utilization efficiency when it produces | generates electricity with a current density of 80 mA / cm < ² > can be made into 20% or more. In addition, the solid oxide fuel cell 14 whose composition, structure, setting, etc. are adjusted so that the fuel utilization efficiency is 20% or more is preferable. Particularly preferably, it is 30% or more, more preferably 40% or more.

  Specifically, as described above, leakage of air from outside the system, that is, oxygen, is reduced as much as possible by improving the sealing performance, or the opening diameter of the anode 111 to the atmosphere is reduced. This is realized by reducing the loss of carbon monoxide (CO) in the reaction formula (1) and / or the reaction formula (2) by suppressing the inflow of oxygen to the anode 111.

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to these Examples.

Example 1
As an electrolyte, ScSZ thickness 0.3 mm _(Sc 2 of 10 mole% _{O 3} and ZrO ₂ 1 mole% of CeO ₂ doped) using a disk, the anode material, Ni / GDC (Gd doped The CeO ₂ ) porous cermet was used, and a La _0.85 Sr _0.15 MnO ₃ porous film was used as a cathode material. The anode thickness was 50 μm. The configuration and the manufacturing method followed the configuration and manufacturing method of a general solid oxide fuel cell. That is, the anode material and cathode material powders were dispersed in a solvent, and an organic binder or the like was added to prepare a slurry. Next, the slurry was applied to a disk by a doctor blade method and fired to prepare a solid oxide fuel cell.

  In this way, a solid oxide fuel cell as shown in FIG. 5 was produced. Carbon black (“MA7” manufactured by Mitsubishi Chemical Corporation) is used as a pseudo-substance of particulate matter contained in exhaust gas in order to confirm that the particulate matter contained in exhaust gas is consumed (removed) as fuel to generate power. (Hereinafter abbreviated as “CB”), the fuel chamber was filled with 28.3 mg of CB.

  In this embodiment, CB was directly supplied to the fuel chamber. However, if the solid oxide fuel cell obtained above is used as an electrochemical reactor, the exhaust gas discharged from the internal combustion engine collected by the cyclone collector. Solid carbon contained in the particulate matter contained therein can be used as a fuel, and the particulate matter can be treated (removed).

Thereafter, pure argon (Ar) was supplied to the anode at 202 STPmL / min for about 1 hour, and residual gas such as O ₂ was exhausted sufficiently. During the treatment, pure oxygen was supplied as an oxidizing agent to the cathode side. The cell was securely sealed, a 3.5 m 1/8 inch stainless steel tube was connected from the anode, and the gas chromatograph was sandwiched between the cells and the gas was exhausted to the outside with a 5 m vinyl tube (inner diameter: 8 mm).

Electric power was generated when the current was adjusted to a constant current density at 900 ° C., and the change with time in the terminal voltage at each power density was monitored. A maximum output density of 20.3 mW / cm ² was obtained at a current density of 33.0 mA / cm ² . Therefore, it has been shown that solid carbon contained in the particulate matter contained in the exhaust gas discharged from the internal combustion engine can be consumed and generated in the same manner. In addition, it was shown that the solid carbon in the particulate matter contained in the exhaust gas is removed, and the exhaust gas can be purified.

  When a solid oxide fuel cell similar to the above is used as an electrochemical reactor and a particulate matter contained in exhaust gas discharged from the internal combustion engine is processed using an apparatus equipped with an electrostatic precipitator, it is discharged from the internal combustion engine. Electric power can be generated by consuming solid carbon in the particulate matter contained in the exhaust gas. Further, the solid carbon in the particulate matter contained in the exhaust gas is removed, and the exhaust gas can be purified.

  Since the present invention can remove particulate matter contained in exhaust gas discharged from an internal combustion engine, the present invention is widely used in the field using an internal combustion engine such as a diesel engine or a gas turbine engine.

1 Intake pipe 2 Cyclone collector 3 Partition plate 4 DPF (Diesel particulate filter)
5 Compartment 11 Exhaust pipe 13 Oxygen supply pipe 14 Electrochemical reactor
(In aspect 1, a solid oxide fuel cell, and in aspect 2, a solid oxide processing apparatus)
15 lead 16 discharge electrode 17 collection electrode 18 a DC power source 19 switch 100 exhaust gas purification system 102 solid carbon 103 carbon dioxide (CO ₂₎ outlet 111 anode 111a anode current collector 111b anode material 121 electrolyte 122 external control circuit 123 electrically Circuit 131 Cathode 131a Cathode current collector 131b Cathode material H Exhaust gas E Internal combustion engine D Electric dust collector C Automobile

Claims (11)

  An exhaust gas purification system comprising a cyclone collector for collecting particulate matter contained in exhaust gas discharged from an internal combustion engine, wherein the particulate matter collected by the cyclone collector is collected by a cyclone collector An exhaust gas purification system characterized in that the exhaust gas is supplied to an electrochemical reactor in a compartment attached to the chamber, and the electrochemical reactor electrochemically removes the supplied particulate matter.   The electrochemical reactor is a solid oxide fuel cell using the particulate matter as a fuel, the solid oxide fuel cell having an anode having an anode material containing a composite metal oxide, a cathode having a cathode material, And an electrolyte containing an ion conductive solid oxide disposed between the anode and the cathode, and reacting solid carbon in the particulate matter with carbon dioxide generated by power generation to carbon monoxide. 2. The exhaust gas purification system according to claim 1, wherein the exhaust gas purification system converts power and generates electric power by oxidizing the carbon monoxide.   The electrochemical reactor is a solid oxide processing apparatus, wherein the solid oxide processing apparatus is an anode having an anode material, a cathode having a cathode material, and an ionic conductivity disposed between the anode and the cathode. At least an electrolyte containing a solid oxide, and by applying a voltage between the anode and the cathode, oxygen ions are transferred to the anode, and the oxygen ions and solid carbon in the particulate matter are formed on the anode. The exhaust gas purification system according to claim 1, wherein the gas is electrochemically reacted.   Supplying a partition plate between the cyclone collector and the compartment, and supplying particulate matter collected by the cyclone collector to the electrochemical reactor from the cyclone collector side of the partition plate The exhaust gas purification system according to any one of claims 1 to 3, further comprising a control unit that determines timing.   A partition plate is provided between the cyclone collector and the compartment, and when the collected particulate matter reaches a certain weight, the partition plate opens and the electrochemical device starts from the bottom of the cyclone collector. The exhaust gas purification system according to any one of claims 1 to 4, wherein the particulate matter is supplied to an anode of a reactor.   The exhaust gas purification system according to any one of claims 1 to 5, further comprising an electric dust collector between the cyclone collector and the internal combustion engine.   The exhaust gas according to any one of claims 1 to 6, wherein the operation of the electrochemical reactor is started by supplying carbon monoxide or carbon dioxide to solid carbon in the particulate matter supplied as fuel. Purification system.   8. The exhaust gas purification system according to claim 2, wherein a tip of a power generation initiator introduction pipe for supplying a power generation initiator at the start of power generation is arranged on the anode side. .   9. The exhaust gas according to claim 2, wherein the exhaust gas is operated while increasing the current density from its initial value immediately after the start of power generation of the solid oxide fuel cell. Purification system.   10. The exhaust gas purification system according to claim 2, wherein an oxygen source is electrochemically injected into the anode at the start of power generation. 11. The claim according to claim 2, wherein the solid oxide fuel cell generates power using the following reaction formulas (1) and (2) during power generation. The exhaust gas purification system described.
CO ₂ + C → 2CO (1)
CO + O ²⁻ → CO ₂ + 2e ⁻ (2)

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