JP2020015636A - Fuel reformer - Google Patents

Abstract

To provide a fuel reformer which can be reduced in weight and size and can promote production of a reforming gas having high reducing power.SOLUTION: A fuel reformer 1 generates a reforming gas Gfrom a hydrocarbon fuel F. The fuel reformer has a reactor 2 and a partition wall 3. The partition wall 3 partitions the inside of the reactor 2 into an oxidation reaction chamber 21 and a fuel reforming chamber 22. The partition wall 3 has a first main surface 31 and a second main surface 32. The oxidation reaction chamber 21 faces the first main surface 31 and is exposed to an oxidation atmosphere. The fuel reforming chamber 22 faces the second main surface 32 and is supplied with a hydrocarbon fuel and exposed to a reducing atmosphere. The partition wall 3 contains a reforming catalyst composed of a metal and/or a metal oxide excluding a predetermined noble metal species.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fuel reformer provided with a partition containing a reforming catalyst for reforming fuel.

  A fuel reformer that reforms a hydrocarbon fuel to generate a reformed gas such as hydrogen is known. The reformed gas is used for, for example, purification of exhaust gas and fuel.

  As an application for purifying exhaust gas, for example, there is a reducing gas used in an SCR (selective catalytic reduction) system. Examples of fuel applications include hydrogen supplied to the fuel electrode side of a fuel cell and reformed fuel used as an energy source in a chemical factory.

  Patent Literature 1 proposes a fuel reformer that reforms a hydrocarbon-based fuel with a catalyst such as a rhodium catalyst, a platinum catalyst, a ruthenium catalyst, a palladium catalyst, and a gold catalyst to generate hydrogen. This fuel reformer aims to improve the hydrogen generation efficiency by forming a high-density part with a large specific surface area of the catalyst and a low-density part with a small specific surface area of the catalyst in the reforming part. I have.

JP-A-2002-308604

  However, in the fuel reformer described in Patent Document 1, a noble metal species having high oxidizing power such as rhodium and platinum is used as a reforming catalyst. Such a reforming catalyst tends to completely oxidize hydrocarbon fuel to carbon dioxide and water. That is, partial oxidation of the hydrocarbon fuel is less likely to occur, and the generation of reformed gas containing hydrogen, oxygen-containing hydrocarbon, and the like is suppressed. As a result, the reducing power required for the reformed gas cannot be sufficiently obtained.

  For example, a fuel reformer for a vehicle is required to be reduced in size and weight from the viewpoint of improving fuel efficiency. For applications other than vehicles, downsizing and weight saving contribute to improved transportability and diversification of installation locations. However, when the reforming catalyst contains a noble metal species having a high oxidizing power, it is necessary to control the oxidizing power of the reforming catalyst to hydrocarbon fuel to be low in order to generate a reforming gas having a high reducing power. . Therefore, it is necessary to adjust the timing of fuel supply to the reformer, the amount of fuel supply, the temperature inside the reformer, and the like. Therefore, it is necessary to mount various sensors and control devices on the fuel reformer, and the fuel reformer tends to be increased in size and weight.

  The present invention has been made in view of such problems, and aims to provide a fuel reformer that can be reduced in weight and size and that can promote generation of a reforming gas having a high reducing power. It is.

One aspect of the present invention is a fuel reformer (1) for producing a reformed gas (G _R ) from a hydrocarbon fuel (F),
A reactor (2);
A partition (3) that partitions the inside of the reactor and has a first main surface (31) and a second main surface (32);
An oxidation reaction chamber (21) facing the first main surface and exposed to an oxidizing atmosphere;
A fuel reforming chamber (22) facing the second main surface and supplied with the hydrocarbon fuel and exposed to a reducing atmosphere;
Fuel reforming, wherein the partition contains a reforming catalyst comprising a metal and / or a metal oxide, wherein the reforming catalyst is substantially free of Pt, Rh, Ru, Pd, Au, Os, and Ir. In the bowl.

  The fuel reformer has a reactor and a partition. The partition partitions the inside of the reactor into an oxidation reaction chamber and a fuel reforming chamber. The partition contains a reforming catalyst composed of a metal and / or a metal oxide. The reforming catalyst in the partition is oxidized by the oxidizing atmosphere of the oxidation reaction chamber on the first main surface side and is reduced by the hydrocarbon fuel on the second main surface side. Therefore, the reforming catalyst changes reversibly between the metal and the metal oxide.

  On the second principal surface side, the reforming catalyst is reduced and the hydrocarbon fuel is oxidized. Since hydrocarbon fuel is oxidized by oxygen in a metal oxide having weak oxidizing power, it is likely to be partially oxidized. Furthermore, since the reforming catalyst does not contain Pt, Rh, Ru, Pd, Au, Os, and Ir, the oxidizing power for the hydrocarbon fuel is suppressed even in a metal state. This suppresses generation of carbon dioxide and water due to complete oxidation of the hydrocarbon fuel, and facilitates generation of hydrogen and oxygen-containing hydrocarbon by partially oxidizing the hydrocarbon fuel. Therefore, generation of a reformed gas having a high reducing power is promoted.

  In the above embodiment, the partition contains the reforming catalyst. That is, the reforming catalyst is fixed to the partition walls to form a so-called fixed bed. Therefore, it is possible to reduce the size and weight of the fuel reformer, for example, as compared to a reformer having a fluidized bed in which the reforming catalyst flows.

  As the reforming catalyst, a catalyst having high oxidizing power is not necessarily required. Therefore, in order to control the oxidizing power of the reforming catalyst to be weak, for example, there is no need to adjust various conditions such as the fuel supply amount, the fuel supply timing, and the temperature inside the reformer. That is, it is possible to reduce or eliminate various sensors and control devices for adjusting various conditions. As a result, the size and weight of the fuel reformer can be reduced.

As described above, according to the above aspect, it is possible to provide a fuel reformer that can be reduced in weight and size and can promote generation of a reformed gas having a high reducing power.
Note that reference numerals in parentheses described in the claims and means for solving the problems indicate the correspondence with specific means described in the embodiments described below, and limit the technical scope of the present invention. Not something.

FIG. 2 is a schematic diagram illustrating a configuration of a fuel reformer according to the first embodiment. FIG. 4 is a schematic diagram of an exhaust gas purification system according to a second embodiment. The schematic diagram of the exhaust gas purification system in the modification 1. The schematic diagram of the exhaust gas purification system in the modification 2. The schematic diagram of the exhaust gas purification system in the modification 3. The schematic diagram of the exhaust gas purification system in the modification 4. FIG. 9 is a schematic diagram illustrating a configuration of a fuel reformer according to a third embodiment.

(Embodiment 1)
An embodiment according to a fuel reformer will be described with reference to FIG. The fuel reformer 1, reforming a hydrocarbon fuel F, used to generate the reformed gas G _R. Examples of the hydrocarbon fuel F include fossil fuels such as light oil, gasoline, and natural gas.

Reformed gas G _R include, for example, hydrogen, oxygenated hydrocarbons. The oxygen-containing hydrocarbon is a hydrocarbon to which oxygen is bonded, and when the hydrocarbon is represented by “HC”, the oxygen-containing hydrocarbon is represented by “HCO”.

  As illustrated in FIG. 1, the fuel reformer 1 has a reactor 2 and a partition 3. The partition 3 divides the inside of the reactor 2 into an oxidation reaction chamber 21 and a fuel reforming chamber 22.

  The partition 3 is, for example, plate-shaped, and has a first main surface 31 and a second main surface 32. The partition 3 contains a reforming catalyst composed of a metal and / or a metal oxide. The metal and the metal oxide can change mutually reversibly in the partition 3. Examples of the metal include metals other than Pt, Rh, Ru, Pd, Au, Os, and Ir. In the present specification, Pt, Rh, Ru, Pd, Au, Os, and Ir are appropriately referred to as “high oxidizing metals”. Specifically, the metal of the reforming catalyst is a transition metal, a rare earth, a noble metal other than the high oxidizing metal, or the like. Specific examples of the transition metal include Mn, Fe, Co, Ni, Cu, and Zn. Specific examples of the rare earth include Y, La, Ce, Pr, and Nd. Ag is exemplified as a noble metal other than the high oxidizing metal. The metal oxide is an oxide containing a metal other than a metal having a high oxidizing power, and is a concept including not only an oxide containing a single metal but also a composite oxide containing two or more metals. The metal oxide includes an ion-conductive solid electrolyte such as a fluorite composite oxide, a perovskite composite oxide, and a spinel composite oxide.

  The partition 3 only needs to contain a reforming catalyst, and the partition 3 may be entirely composed of a reforming catalyst. However, the partition 3 is composed of a base material and a reforming catalyst dispersed in the base material. May be configured. The partition 3 may be composed of a single layer or a laminate. FIG. 1 illustrates a single-layer partition wall 3.

The oxidation reaction chamber 21 is a reaction chamber partitioned by the partition 3 and faces the first main surface 31 of the partition 3. The oxidation reaction chamber 21 is exposed to an oxidizing atmosphere. The oxidizing atmosphere is, for example, a gas atmosphere containing oxygen. The gas containing oxygen is called “oxygen-containing gas”. By supplying the oxygen-containing gas G _O to the oxidation reaction chamber 21, the inside of the oxidation reaction chamber 21 can be easily made to have an oxidation atmosphere.

  The oxygen gas concentration in the oxidation reaction chamber 21 is, for example, preferably 5% by volume or more, more preferably 7% by volume or more, and more preferably 10% by volume or more, from the viewpoint of facilitating the oxidation reaction. Is more preferred. The oxygen gas concentration is monitored by, for example, an oxygen sensor (not shown).

Examples of the oxygen-containing gas G _O include exhaust gas discharged from the internal combustion engine, the atmosphere, and the like. That is, the oxidizing atmosphere is, for example, an exhaust gas atmosphere or an air atmosphere. By supplying the exhaust gas and the atmosphere to the oxidation reaction chamber 21, the inside of the oxidation reaction chamber 21 can be easily made to have an oxidation atmosphere. When the exhaust gas is supplied, there is also an advantage that the heat of the exhaust gas can be used for the fuel reforming reaction in the fuel reformer 1.

The oxidation reaction chamber 21 is constituted by a gas flow path, and it is preferable that the flow path adjustment valve 11 is provided upstream of the gas flow path of the oxidation reaction chamber 21. For example, a gas flow path is formed by providing a gas inlet and a gas outlet in the oxidation reaction chamber 21 and connecting an oxidizing gas inlet pipe 211 and an oxidizing gas outlet pipe 212 to the gas inlet and the gas outlet, respectively. be able to. The flow path adjustment valve 11 adjusts the flow rate of, for example, the oxygen-containing gas G _O into the oxidation reaction chamber 21. The flow path regulating valve 11 can also block the flow of the oxygen-containing gas G _O into the oxidation reaction chamber and reduce the flow rate to zero. The oxidation reaction in the oxidation reaction chamber 21 can be controlled by adjusting the flow rate of the oxygen-containing gas G _O by the flow path adjustment valve 11. The installation position of the flow path adjustment valve 11 can be appropriately adjusted.

  The partition 3 is oxidized in the oxidation reaction chamber 21. Specifically, the metal of the reforming catalyst is oxidized to generate a metal oxide. The oxidation of the partition wall 3 proceeds on the first main surface 31 side. The first main surface 31 can also be called an oxidized surface.

  The fuel reforming chamber 22 is a reaction chamber partitioned by the partition 3 and faces the second main surface 32 of the partition 3. The hydrocarbon fuel F is supplied into the fuel reforming chamber 22, and the fuel reforming chamber 22 is exposed to a reducing atmosphere.

The fuel reforming chamber 22 is constituted by a gas flow path, and the fuel injection valve 5 is preferably provided upstream of the gas flow path of the fuel reforming chamber 22. For example, a gas passage is formed by providing a gas inlet and a gas outlet in the fuel reforming chamber 22 and connecting a fuel inlet pipe 221 and a reformed gas outlet pipe 222 to the gas inlet and the gas outlet, respectively. can do. The fuel injection valve 5 supplies the hydrocarbon fuel F into the fuel reforming chamber 22. The control of the fuel injection timing and injection amount can be performed by a fuel injection control circuit (not shown) electrically connected to the fuel injection valve 5.

The fuel injection valve 5 can supply the hydrocarbon fuel F into a fuel introduction pipe 221 connected to a gas introduction port of the fuel reforming chamber 22, for example. Thereby, the hydrocarbon fuel F is supplied to the upstream of the fuel reforming chamber 22, and the hydrocarbon fuel F is introduced into the fuel reforming chamber 22 by the airflow. By adjusting the installation position of the injection port of the fuel injection valve 5, for example, the hydrocarbon fuel F can be directly supplied into the fuel reforming chamber 22. In any case, the fuel injection valve 5 is configured to supply the hydrocarbon fuel F into the fuel reforming chamber 22. Reformed gas G _R generated in the fuel reforming chamber 22 is discharged from the gas discharge port, the reformed gas G _R is used for various applications.

  A flow path adjustment valve can be provided upstream of the gas flow path of the fuel reforming chamber 22. The flow of the hydrocarbon fuel F into the fuel reforming chamber 22 and the flow rate thereof can be adjusted by the flow path adjustment valve. The installation positions of the fuel injection valve 5 and the flow path adjustment valve can be appropriately adjusted. The illustration of the flow path adjustment valve provided upstream of the gas flow path of the fuel reforming chamber is omitted.

  The fuel reformer 1 can include at least two fuel injection valves 5. Specifically, a first fuel injection valve 51 and a second fuel injection valve 52 can be provided. It is preferable that both the first fuel injection valve 51 and the second fuel injection valve 52 are configured to supply fuel into the fuel reforming chamber 22 with a temporal phase difference. In this case, the first fuel injection valve 51 and the second fuel injection valve 52 can, for example, alternately inject the hydrocarbon fuel F. Therefore, control of the injection timing and the injection amount is facilitated, and the hydrocarbon fuel F is easily supplied at the optimum timing and amount. The injection control by the first fuel injection valve 51 and the second fuel injection valve 52 is performed by, for example, a fuel injection control circuit (not shown).

  In the fuel reforming chamber 22, the partition 3 is reduced. Specifically, the metal oxide of the reforming catalyst is reduced to generate a metal. The reduction of the partition walls 3 proceeds on the second main surface 32 side. The second main surface 32 can also be referred to as a reduction surface.

  An oxidation reaction of the partition wall 3 occurs on the first main surface 31 side of the partition wall 3, and a reduction reaction of the partition wall 3 occurs on the second main surface 32 side. Specifically, on the first main surface side, the metal is oxidized to generate a metal oxide, and on the second main surface side, the metal oxide is reduced to generate a metal. Therefore, as illustrated in FIG. 1, the partition wall 3 receives the oxygen in the oxidation reaction chamber 21 on the first main surface 31 side, and receives the hydrocarbon fuel F (specifically, HC) on the second main surface 32 side. Play the role of passing to. In the partition 3, the metal of the reforming catalyst becomes a metal oxide on the first main surface 31 side and the metal oxide becomes a metal on the second main surface 32 side, so that oxygen is removed from the first main surface 31. It shows a behavior of moving to the second main surface 32 side. In FIG. 1, a metal is represented by Me, and a metal oxide is represented by MeO. From the viewpoint that the oxidation reaction and the reduction reaction in the partition walls are more likely to occur, the thickness of the partition walls 3 is preferably 0.01 mm to 0.1 mm, and more preferably 0.015 mm to 0.05 mm. .

  In the fuel reforming chamber 22, the metal oxide is reduced to generate a metal, and the hydrocarbon fuel F is oxidized. Oxygen in the metal oxide is used for the oxidation of the hydrocarbon fuel F. Since oxygen in the metal oxide has a lower oxidizing power than gaseous oxygen, partial oxidation of the hydrocarbon fuel F is promoted. Furthermore, since the reforming catalyst does not contain a metal having a high oxidizing power, a strong oxidizing effect on the hydrocarbon fuel F can be avoided. Therefore, it is possible to prevent the hydrocarbon fuel F from being completely oxidized to carbon dioxide and water by the reforming catalyst in the partition 3. As described above, in the fuel reforming chamber 22, partial oxidation of the hydrocarbon fuel F is likely to occur due to gentle oxidation by oxygen in the metal oxide and avoidance of strong oxidation. Therefore, oxygen-containing hydrocarbons and hydrogen are easily generated from the hydrocarbon fuel F.

The reforming reaction of the hydrocarbon fuel F by the partial oxidation in the fuel reforming chamber 22 is represented by the following equations (1) and (2). Equation (1) represents a reforming reaction to hydrogen, and equation (2) represents a reforming reaction to oxygen-containing hydrocarbon. In the formulas (1) and (2), HC represents a hydrocarbon, Me represents a metal, MeO represents a metal oxide, and HCO represents an oxygen-containing hydrocarbon.
HC + MeO → Me + CO + 1 / 2H ₂ (1)
HC + MeO → Me + HCO (2)

  It is preferable that the fuel reforming chamber 22 does not substantially contain oxygen gas. By making the oxygen gas concentration in the fuel reforming chamber 22 substantially equal to or close to 0% by volume, complete oxidation of the hydrocarbon fuel F is further suppressed. However, maintaining the oxygen gas concentration in the fuel reforming chamber 22 at 0% by volume makes it difficult to control the gas composition in the fuel reforming chamber 22. Therefore, from the viewpoint that the gas composition in the fuel reforming chamber 22 is easily controlled, the presence of the oxygen gas in the fuel reforming chamber 22 is allowed to some extent.

The tolerance is dependent on the type of reformed gas G _R (specifically, component composition). For example, in order to easily generate oxygen-containing hydrocarbons, it is preferable that the oxygen gas concentration in the fuel reforming chamber 22 be less than 5% by volume. In order to easily generate hydrogen, it is preferable that the oxygen gas concentration in the fuel reforming chamber 22 be less than 1% by volume. For example, when the hydrocarbon fuel F is light oil, the amount of oxygen with respect to the hydrocarbon fuel in the fuel reforming chamber 22 is preferably 0.5 to 10 by mole ratio, and more preferably 5 to 8 in molar ratio. More preferably, it is still more preferably 6 to 7. This molar ratio is expressed as oxygen (unit: mol) / fuel (unit: mol).

  The oxygen gas concentration in the fuel reforming chamber 22 is monitored by, for example, an oxygen sensor (not shown). The control of the oxygen gas concentration is performed by supplying the hydrocarbon fuel F into the fuel reforming chamber 22. Specifically, when the hydrocarbon fuel F is supplied into the fuel reformer 22, the oxygen gas in the fuel reforming chamber 22 is consumed, and the oxygen gas concentration decreases. When the fuel injection valve 5 is provided, the hydrocarbon fuel F may be injected by the fuel injection valve 5 when the oxygen gas concentration becomes equal to or higher than a predetermined value. Thus, the oxygen gas concentration in the fuel reforming chamber 22 can be kept, for example, below a predetermined value.

  The oxidation reaction of the partition walls 3 in the oxidation reaction chamber 21 is an exothermic reaction. The reduction reaction of the partition walls 3 in the fuel reforming chamber 22 is an endothermic reaction. The heat generated by the oxidation reaction is transmitted to the partition wall 3 and used for the reduction reaction. In the fuel reformer 1, the heat balance can be controlled. Specifically, the temperature of the reformer can be controlled by controlling the amount of the reduction reaction (that is, the amount of the endothermic reaction) and the amount of the oxidation reaction (that is, the amount of the exothermic reaction). In FIG. 1, “ht” indicates heat, and a dashed arrow indicates heat transfer.

The temperature in the reactor 2 is preferably adjusted to 100 to 500 ° C. In this case, the generation of oxygen-containing hydrocarbons and hydrogen is further promoted. As a result, generation of high reducing power reformed gas G _R is further promoted.

  From the viewpoint that oxygen-containing hydrocarbons are easily generated, the temperature in the reactor 2 is preferably 200 to 400 ° C. From the viewpoint that hydrogen is easily generated, the temperature in the reactor 2 is preferably 300 to 500 ° C.

  The temperature adjustment in the reactor 2 can be controlled by, for example, the balance between the oxidation reaction in the oxidation reaction chamber 21 and the reduction reaction in the fuel reforming chamber 22. This is because the oxidation reaction is an exothermic reaction and the reduction reaction is an endothermic reaction, so that the temperature of the partition wall 3 can be adjusted by adjusting the balance between the two. Therefore, it is possible to avoid installing a heater for heating the inside of the reactor 2.

Specifically, by increasing the oxygen gas concentration in the oxidation reaction chamber 21, increasing the flow rate of the oxygen-containing gas G _O , or decreasing the supply amount of the hydrocarbon fuel F into the fuel reforming chamber 22, The temperature in the vessel 2 can be increased. On the other hand, by increasing the supply amount of the hydrocarbon fuel F into the fuel reforming chamber 22, the temperature inside the reactor 2 can be lowered.

  The fuel reformer 1 may include a heater 48. In this case, the inside of the reactor 2 can be heated by the heater 48, and the temperature of the fuel reformer 1 can be adjusted. This facilitates temperature control.

As illustrated in FIG. 1, in the fuel reformer 1, the partition 3 divides the inside of the reactor 2 into an oxidation reaction chamber 21 and a fuel reforming chamber 22. The partition 3 contains a reforming catalyst composed of a metal and / or a metal oxide. The reforming catalyst in the partition wall 3 is oxidized by oxygen in the oxidation reaction chamber 21 on the first main surface 31 side, and reduced by the hydrocarbon fuel F on the second main surface 32 side. On the second main surface 32 side, the hydrocarbon fuel F is oxidized together with the reduction of the reforming catalyst. The hydrocarbon fuel F is oxidized by oxygen in the metal oxide having low oxidizing power. Therefore, partial oxidation of the hydrocarbon fuel F easily occurs. That is, complete oxidation of the hydrocarbon fuel F is suppressed, and partial oxidation is promoted. Thus, oxygen-containing hydrocarbons, including hydrogen, generation of high reformed gas G _R reducing power is promoted.

  The reforming catalyst is fixed to the partition walls 3 to form a so-called fixed bed, and the reforming catalyst itself does not flow. Therefore, a flow space and a flow device for flowing the reforming catalyst are not required, and the size and weight of the fuel reformer 1 can be reduced.

  The reforming catalyst is made of a transition metal and / or a transition metal oxide, and the partition walls 3 do not require a noble metal species having a high oxidizing power such as a high oxidizing metal as the reforming catalyst. Therefore, it is not necessary to adjust various conditions such as a fuel supply amount, a fuel supply timing, and a temperature in the reformer in order to reduce, for example, the oxidizing ability of the catalyst having a high oxidizing power. That is, it is possible to reduce or eliminate various sensors and control devices necessary for adjusting these conditions. As a result, the size and weight of the fuel reformer 1 can be reduced. The partition wall 3 may contain a noble metal such as Ag, for example, in a range that does not significantly hinder the partial oxidation. It is preferable that substantially no noble metal is contained.

  The reforming catalyst in the partition 3 does not substantially contain a high oxidizing metal. This means that a high oxidizing metal can be contained within a range that does not significantly hinder the partial oxidation of the reforming catalyst. It is preferable that the high oxidizing metal is a trace amount that does not affect the oxidation reaction or reduction reaction of the reforming catalyst. From the viewpoint of more fully suppressing the complete oxidation of the hydrocarbon fuel F, the reforming catalyst may not contain a metal having a high oxidizing power at all, and preferably does not substantially contain a noble metal.

As the reforming catalyst, a solid electrolyte can be used. In this case, oxygen in the oxidation reaction chamber 21 is taken into the solid electrolyte 3 from the first main surface 31 of the partition wall 3 as, for example, oxygen ions, and oxygen ions move to the second main surface 32 side in the solid electrolyte. I do. Then, oxygen is passed from the second main surface 32 to the hydrocarbon fuel F. In this case, the transmission of oxygen becomes smooth, and the oxidation reaction and the reduction reaction easily proceed. Furthermore, the dense partition walls 3 can be formed by the solid electrolyte. The dense partition wall 3 prevents the oxygen-containing gas _Go in the oxidation reaction chamber 21 from passing through the partition wall 3 and reaching the fuel reforming chamber 22, and the hydrocarbon fuel F and the reformed gas G in the fuel reforming chamber 22. _R is prevented from reaching the oxidation reaction chamber 21 through the partition wall 3. Examples of the solid electrolyte include yttria-stabilized zirconia (that is, YSZ), ZrO ₂ , CeO ₂ , and Bi ₂ O ₃ .

  The partition walls 3 may be formed of a laminate, and different materials may be used as the reforming catalysts constituting each layer of the partition walls 3. In this case, a plurality of metals, a plurality of solid electrolytes may be used, or a metal and a solid electrolyte may be used in combination.

The fuel reformer 1, the reformed gas G _R applications are not particularly limited. Reformed gas G _R is used, for example, as the reducing of the fuel. Specifically, the reformed gas G _R, the fuel supplied to the fuel electrode side of the fuel cell is used as a reforming fuel such as used in the factory.

Reformed gas G _R is used for purifying exhaust gas, such as purification of NOx as described in the embodiment 2 described later. In this case, the high reducing power reformed gas G _R, it is possible to sufficiently purify NOx. More specifically, it is possible to apply the reformed gas G _R in selective catalytic reduction (SCR) system. In this case, the purification performance of the SCR system is improved by the high reducing power of the reformed gas G _R.

  As described above, the fuel reformer 1 of the present embodiment can be reduced in size and weight. Therefore, the fuel reformer 1 is suitable for a vehicle. The installation space can be reduced, and the fuel efficiency can be improved.

(Embodiment 2)
An embodiment of a vehicle-mounted fuel reformer 1 used for exhaust gas purification will be described. Note that, among the reference numerals used in the second and subsequent embodiments, the same reference numerals as those used in the above-described embodiments represent the same components and the like as those in the above-described embodiments unless otherwise specified.

  As illustrated in FIG. 2, the fuel reformer 1 is used in an exhaust gas purification system 6 using selective catalytic reduction (ie, SCR). The fuel reformer 1 is used as an apparatus for generating a reducing agent in the exhaust gas purification system 6.

  The fuel reformer 1 is used for a post-processing device of an internal combustion engine such as an engine. As exemplified in FIG. 2, the fuel reformer 1 is installed between an engine 61 such as a diesel engine and an SCR catalyst 62, for example. The SCR catalyst 62 is composed of a base material having a honeycomb structure (not shown) and a purification catalyst (not shown) supported on the base material, and is disposed in a diameter-expanded pipe obtained by expanding the exhaust gas pipe 63. The fuel reformer 1 may have the same configuration as in the first embodiment, for example.

  The fuel reformer 1 is connected to an exhaust gas pipe 63 through which exhaust gas discharged from the engine 61 flows. More specifically, a bypass pipe 64 branched from the exhaust gas pipe 63 is connected to the oxidation reaction chamber 21 of the fuel reformer 1. The upstream side of the bypass pipe 64 is connected to a gas inlet of the oxidation reaction chamber 21, and the downstream side of the bypass pipe 64 is connected to a gas outlet of the oxidation reaction chamber 21.

The exhaust gas flowing through the bypass pipe 64 is supplied into the oxidation reaction chamber 21 from the gas inlet, and is discharged out of the oxidation reaction chamber 21 from the gas outlet. Next, the exhaust gas is returned to the exhaust gas pipe 63 through the bypass pipe 64 and reaches the SCR catalyst 62. Exhaust gas not passing through the bypass path is supplied from the engine 61 to the SCR through the exhaust gas pipe 63. The exhaust gas is one type of the oxygen-containing gas G _O , and makes the inside of the oxidation reaction chamber 21 an oxidizing atmosphere.

  The bypass pipe 64 can be provided with the flow path adjusting valve 11. The flow path adjusting valve 11 enables the supply of the exhaust gas into the oxidation reaction chamber 21 and the control of the supply amount.

  Hydrocarbon fuel F is supplied from a gas inlet of the fuel reforming chamber 22. The fuel injection valve 5 is used to supply the hydrocarbon fuel F. The fuel injection valve 5 injects, for example, the hydrocarbon fuel F into a fuel introduction pipe 221 connected to a gas introduction port. In the fuel introduction pipe 221, the hydrocarbon fuel F is supplied into the fuel reforming chamber while the surrounding atmosphere gas flows.

Hydrocarbon fuel F is reformed in the fuel reforming chamber 22, the reformed gas G _R is produced. The reforming of the hydrocarbon fuel F in the reformer 1 is performed in the same manner as in the first embodiment. Reformed gas G _R is supplied to the SCR catalyst 62 from the gas discharge port of the fuel reforming chamber 22. Supply path of the reformed gas G _R is not particularly limited, for example, can supply the exhaust gas resulting from the gas outlet to the exhaust gas pipe 63 connecting the engine 61 and the SCR catalyst 62. That is, the reformed gas discharge pipe 222 connected to the gas discharge port of the fuel reforming chamber 22 is connected to, for example, an exhaust gas pipe 63 connecting the engine 61 and the SCR catalyst 62. From the viewpoint of reformed gas G _R supplied to the SCR catalyst 62 while sufficiently retaining the reducing power of the reformed gas G _R, be made close to the connecting position to the exhaust gas pipe 63 of the reformed gas discharge pipe 222 to the SCR catalyst 62 preferable.

  In the exhaust gas purification system 6 of the present embodiment, for example, a urea water tank required in a urea SCR system is not required. Therefore, an installation space for the tank is not required, and replenishment of urea water is not required.

In the present embodiment, high reformed gas reducing power generated by the fuel reformer 1 G _R is supplied to the SCR catalyst 62. As a result, the SCR catalyst 62, NOx is sufficiently reduced to the N ₂ and H ₂ O, it is possible to sufficiently purify of NOx. That is, the fuel reformer 1 enables the purification performance of the SCR catalyst 62 to be improved.

(Modification 1)
For example of changing the discharge path of the reformed gas G _R and Embodiment 2 from the fuel reformer 1 is described. As illustrated in FIG. 3, this example is an example of an exhaust gas purification system 6 including an engine 61, an SCR catalyst 62, and a fuel reformer 1, as in the second embodiment.

As illustrated in FIG. 3, the reformed gas discharge pipe 222 discharged from the fuel reforming chamber 22 can be connected to a not-shown enlarged pipe in which the SCR catalyst 62 is disposed. In the expanded tube in which the SCR catalyst 62 is disposed, for example, a DPF (diesel particulate filter) (not shown) is disposed in addition to the SCR catalyst 62. The reformed gas discharge pipe 222 can be connected at least upstream of the SCR catalyst 62 in the enlarged diameter pipe. In this example, the reformed gas G _R generated in the fuel reforming chamber 22 of the fuel reformer 1 is supplied to the expanded tube containing the SCR catalyst 62 through the reformed gas discharge pipe 222. Other configurations are the same as those of the second embodiment.

(Modification 2)
An example in which the introduction path of the oxygen-containing gas G _{O to} the fuel reformer 1 and the discharge path of the oxygen-containing gas G _O from the fuel reformer 1 are changed from the second embodiment will be described. As illustrated in FIG. 4, this example is an example of an exhaust gas purification system 6 including an engine 61, an SCR catalyst 62, and a fuel reformer 1, as in the second embodiment.

  As illustrated in FIG. 4, the fuel reformer 1 can be connected to an exhaust gas pipe 63 connecting the engine 61 and the SCR catalyst 62 without using a bypass pipe. Specifically, the oxidation reaction chamber 21 of the fuel reformer 1 can be directly connected to the exhaust gas pipe 63. In this case, the exhaust gas flowing through the exhaust gas pipe 63 is supplied into the oxidation reaction chamber 21 from the gas inlet of the oxidation reaction chamber 21, and is discharged from the gas outlet of the oxidation reaction chamber 21 to the exhaust gas pipe 63.

  In the example of FIG. 4, the connection position of the reformed gas discharge pipe 222 is the exhaust gas pipe 63, as in the second embodiment, but the connection position may be an expanded pipe as in the first modification. is there. That is, the configuration of the first modification and the configuration of the second modification can be combined.

(Modification 3)
An example in which the oxygen-containing gas G _O supplied to the fuel reformer 1 is different from that of the second embodiment will be described. As illustrated in FIG. 5, this example is an example of the exhaust gas purification system 6 including the engine 61, the SCR catalyst 62, and the fuel reformer 1, as in the second embodiment.

The oxygen-containing gas G _O is supplied to the oxidation reaction chamber 21 of the fuel reformer 1. In this example, the atmosphere is used as the oxygen-containing gas G _O. In this case, as illustrated in FIG. 5, the oxidizing gas introduction pipe 211 is not connected to the exhaust gas pipe 63 or the bypass pipe 64 connected to the exhaust gas pipe 63 but is connected to an air introduction unit (not shown). . As a result, the atmosphere is introduced into the oxidation reaction chamber 21 as the oxygen-containing gas G _O. The atmosphere is discharged from the outlet of the oxidation reaction chamber 21 through the oxidizing gas discharge pipe 212.

  The oxidizing gas discharge pipe 212 is connected to, for example, the exhaust gas pipe 63 downstream of the SCR catalyst 62. Thus, the air that has passed through the oxidation reaction chamber 21 is discharged together with the exhaust gas that has passed through the SCR catalyst 62. In FIG. 5, the oxidizing gas discharge pipe 212 and the reformed gas discharge pipe 222 intersect, but they are not actually connected, and the discharge pipes 212 and 222 form different paths. .

(Modification 4)
An example in which the fuel introduction pipe 221 is connected to the engine 61 will be described. As illustrated in FIG. 6, this example is an example of the exhaust gas purification system 6 including the engine 61, the SCR catalyst 62, and the fuel reformer 1, as in the second embodiment.

As illustrated in FIG. 6, the engine 6 and the fuel reforming chamber 22 of the fuel reformer 1 are connected by a fuel introduction pipe 211. Thus, the hydrocarbon fuel F injected into the engine 61 can be directly introduced into the fuel reforming chamber 22. In this case, for example, unburned hydrocarbon fuel F is supplied from the engine 61 into the fuel reforming chamber 22 and used for reforming in the fuel reformer 1. That is directly supplied to the fuel reforming chamber 22 hydrocarbon fuels F supplied to the engine 6 through the fuel introduction pipe 211 is used to generate a reformed gas G _R.

  On the other hand, the exhaust gas from the engine 61 may be supplied to the fuel reforming chamber 22. That is, the fuel introduction pipe 211 may be the exhaust gas pipe 61. The exhaust gas contains an unburned hydrocarbon component and is deficient in oxygen, and such an exhaust gas can be used as the hydrocarbon fuel F reformed in the fuel reforming chamber 22. The gas component of the exhaust gas can be adjusted by controlling the combustion of the hydrocarbon fuel F in the engine 61, for example. When the exhaust gas is supplied into the fuel reforming chamber 22, the exhaust gas is reformed, and for example, a reducing gas and an oxygen-containing gas are generated. That is, the exhaust gas can be reformed into a useful gas.

Reformed gas G _R from the reformed gas discharge pipe 222, is supplied for example to the SCR catalyst 62. The path of the oxygen-containing gas _Go in this example is the same as, for example, the third modification.

(Embodiment 3)
An embodiment of the fuel reformer 1 having the partition walls 3 having a laminated structure will be described. As illustrated in FIG. 7, the partition wall 3 may have a laminated structure in which, for example, the materials of the respective layers are different.

  Specifically, for example, the partition wall 3 is formed by forming an oxide layer 34 facing the oxidation reaction chamber 21, a reduction layer 35 facing the fuel reforming chamber 22, and an intermediate layer 33 sandwiched between the oxide layer 34 and the reduction layer 35. And a three-layer structure. That is, the partition 3 can be a laminated structure in which the oxide layer 34, the intermediate layer 33, and the reduction layer 35 are sequentially laminated.

  The oxide layer 34 can contain, for example, a reforming catalyst made of a material capable of ionizing oxygen. Specifically, a metal and / or metal oxide are contained as a reforming catalyst. The reduction layer 35 contains a metal and / or a metal oxide as a reforming catalyst. The oxidized layer 34 and the reduced layer 35 may partially contain the reforming catalyst, but the entire oxidized layer 34 and the reduced layer 35 may be composed of metal and / or metal oxide, respectively. Oxidation layer 34 has a first main surface 31 facing oxidation reaction chamber 21, and reduction layer 35 has a second main surface 32 facing fuel reforming chamber 22.

  The oxide layer 34 and the reduction layer 35 may be the same material or different materials. When the materials of the oxide layer 34 and the reduction layer 35 are changed, the oxide layer 34 is formed of, for example, a metal or a metal oxide that easily ionizes oxygen, and the reduction layer 35 is formed of, for example, a metal or a metal oxide that is easily reduced. Can be formed. The oxide layer 34 and the reduction layer 35 are made of, for example, a metal oxide or metal other than the solid electrolyte.

  The intermediate layer 33 contains, for example, a solid electrolyte as a reforming catalyst. The intermediate layer 33 may partially contain the solid electrolyte, but the entire intermediate layer 33 may be composed of the solid electrolyte. The partition wall 3 having a laminated structure as in the present embodiment can have a structure similar to the cell structure of a fuel cell in which, for example, an oxygen electrode, an electrolyte, and a fuel electrode are sequentially laminated.

  In the partition 3, for example, metal in the oxide layer 34 is oxidized by oxygen in the oxidation reaction chamber 21. That is, oxygen in the oxidation reaction chamber 21 is taken into the partition 3 from the first main surface 31 of the oxide layer 34. Oxygen moves in the intermediate layer 33 from the oxide layer 34 side to the reduction layer 35 side, for example, in the state of ions (that is, oxygen ions). By appropriately selecting the material of the solid electrolyte of the intermediate layer 33, the conductivity of oxygen ions can be adjusted. For example, by selecting a solid electrolyte having high ion conductivity, the oxygen ion conductivity in the intermediate layer 33 is improved. The oxygen ions that have reached the reduction layer 35 oxidize, for example, a metal in the reduction layer 35 to generate a metal oxide in the reduction layer 35. Then, the metal oxide of the reduction layer 35 enables partial oxidation of the hydrocarbon fuel F as in the first embodiment.

The fuel reformer 1 can include an energy source 4 that supplies external energy to the partition 3. As illustrated in FIG. 7, when an external power supply is provided as the energy source 4, for example, a voltage can be applied to the partition 3, and an electric field is applied to the partition 3. By applying external energy to the partition 3, an oxidation reaction on the first main surface 31 side of the partition 3 and a reduction reaction on the second main surface 32 side can be promoted. In addition, the movement of ions in the solid electrolyte can be promoted. Thus, generation of high reformed gas G _R reducing power is further promoted. The external energy is not limited to an electric field, but may be other energy such as heat, a magnetic field, plasma, and light. The light is, for example, ultraviolet light.

Further, the oxide layer 34 and / or the reduction layer 35 are preferably porous, and the intermediate layer 33 is preferably a dense body. In this case, the inside of the reactor 2 is partitioned by the dense intermediate layer 33, and the porous oxide layer 34 or the porous reduction layer 35 is provided in the oxidation reaction chamber 21 and the fuel reforming chamber 22, respectively. Face to face. As a result, the inside of the reactor 2 can be partitioned by the intermediate layer 33 while increasing the specific surface areas of the oxide layer 34 and the reduction layer 35. The increase in the specific surface area of the oxide layer 34 leads to an increase in the contact area between the oxide layer 34 and the gas phase (specifically, oxygen) in the oxidation reaction chamber 21. As a result, the reactivity of the oxidation reaction in the oxide layer 34 is improved. The same applies to the reduction layer 35. That is, formation of the porous layer 37, the oxidation reaction in the oxidation layer 34 to enhance the reactivity of the reduction reaction in the reduction layer 35, it is possible to further promote the formation of high reformed gas G _R reducing power.

  Further, it is also possible to form the porous layer 37 on the oxidation reaction chamber 21 side and / or the fuel reforming chamber 22 side of the partition 3 while forming the entire partition 3 with, for example, a metal and / or a metal oxide. When having the porous layer 37, the dense layer 36 which partitions the inside of the reactor 2 is formed. The type of metal in the partition 3 may be changed like the above-described oxide layer 34, reduction layer 35, and intermediate layer 33, but may be the same. In this case, the partition 3 has a dense layer 36 and a porous layer 37 laminated on the dense layer 36, and the porous layer 37 faces the oxidation reaction chamber 21 and / or the fuel reforming chamber 22. . Since the formation of the porous layer 37 increases the specific surface area of the partition wall 3, the oxidation reaction on the first main surface 31 and the reduction reaction on the second main surface 32 can be promoted.

  The present invention is not limited to the above embodiments and modifications, and can be applied to various embodiments and modifications without departing from the gist of the invention. In the embodiment, the fuel reformer 1 for in-vehicle use has been mainly described. However, the fuel reformer 1 having the configuration of the first or third embodiment can be used as an energy supply source of a chemical factory, for example. .

DESCRIPTION OF SYMBOLS 1 Fuel reformer 2 Reactor 21 Oxidation reaction chamber 22 Fuel reforming chamber 3 Partition wall 31 1st main surface 32 2nd main surface

Claims (17)

A fuel reformer (1) for producing a reformed gas (G _R ) from a hydrocarbon fuel (F),
A reactor (2);
A partition (3) that partitions the inside of the reactor and has a first main surface (31) and a second main surface (32);
An oxidation reaction chamber (21) facing the first main surface and exposed to an oxidizing atmosphere;
A fuel reforming chamber (22) facing the second main surface and supplied with the hydrocarbon fuel and exposed to a reducing atmosphere;
Fuel reforming, wherein the partition contains a reforming catalyst comprising a metal and / or a metal oxide, and the reforming catalyst is substantially free of Pt, Rh, Ru, Pd, Au, Os, and Ir. vessel.   The fuel reformer according to claim 1, wherein the reforming catalyst comprises a solid electrolyte.   The fuel reformer according to claim 1 or 2, further comprising an energy source (4) for applying external energy to the partition. The fuel reformer according to any one of claims 1 to 4, wherein an oxygen-containing gas ( _G0 ) is supplied to the oxidation reaction chamber.   The fuel reformer according to any one of claims 1 to 4, wherein exhaust gas or air is supplied to the oxidation reaction chamber.   The said oxidation reaction chamber is comprised by the gas flow path, The flow path adjustment valve (11) is provided upstream of the said gas flow path of the said oxidation reaction chamber, The any one of Claims 1-5. A fuel reformer according to claim 1.   The fuel reforming chamber is constituted by a gas passage, and a fuel injection valve (5) is provided upstream of the gas passage in the fuel reforming chamber. A fuel reformer according to item 6.   The fuel injection valve is a first fuel injection valve (51), the fuel reforming chamber is further provided with a second fuel injection valve (52), and the first fuel injection valve and the second fuel injection are provided. The fuel reformer according to claim 7, wherein the hydrocarbon fuel is supplied into the fuel reforming chamber with a temporal phase difference from a valve.   The fuel reformer according to any one of claims 1 to 8, wherein the hydrocarbon fuel is light oil.   The partition includes an intermediate layer (33) containing the reforming catalyst composed of a solid electrolyte, an oxide layer (34) formed on the intermediate layer and facing the oxidation reaction chamber, and an intermediate layer (34) stacked on the intermediate layer. And a reduction layer (35) formed and facing the fuel reforming chamber, wherein the oxidation layer and the reduction layer contain the reforming catalyst comprising a metal and / or metal oxide. The fuel reformer according to any one of claims 1 to 9.   The fuel reformer according to claim 10, wherein the intermediate layer is a dense body, and the oxidized layer and / or the reduced layer is porous.   The partition has a dense layer (36) and a porous layer (37) laminated on the dense layer, and the porous layer faces the oxidation reaction chamber and / or the fuel reforming chamber. A fuel reformer according to any one of claims 1 to 11.   The fuel reformer according to any one of claims 1 to 12, further comprising a heater (48) for heating the inside of the reactor.   The fuel reformer according to any one of claims 1 to 13, wherein the temperature in the reactor is adjusted to 100 to 500C.   The fuel reformer according to any one of claims 1 to 14, wherein the reformed gas is used for fuel.   The fuel reformer according to any one of claims 1 to 15, wherein the reformed gas is used for purifying NOx in exhaust gas.   The fuel reformer according to any one of claims 1 to 16, wherein the fuel reformer is mounted on a vehicle.

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