KR20070025160A - Plate type reformer and fuel cell system having same - Google Patents

Abstract

A plate type reformer and a fuel cell system having the same are provided to improve the reaction efficiency between reacting units, and appropriately control a reaction temperature of each reacting unit even in case that a gap of a reacting temperature between reacting units is big. Combustion reacting units(31,32) have an oxidation catalyst layer on the inside, and generate thermal energy by making a combustion fuel react with an oxidizer. A reforming reacting unit(33) has a reforming catalyst layer on the inside, and generates reforming gas having affluent hydrogen from a reforming fuel through a reforming reaction by thermal energy of the reforming reacting unit. Heat distributing plates(41,42,43) are inserted into spaces between the combustion reacting units and the reforming reacting unit, and have thermal conductivity higher than housings of the combustion reacting units and the reforming reacting unit. A preheating unit(34) has a channel for receiving the reforming fuel and water, and preheats the reforming fuel and the water by thermal energy of the combustion reacting unit. A heat cut-off plate is inserted into a space between the preheating unit and the combustion reacting units, having thermal conductivity lower than a housing of the preheating unit.

Description

Plate type reformer and fuel cell system having same

1 is a view showing a flat plate reformer according to a first embodiment of the present invention.

2A and 2B are exploded perspective views illustrating a heat distribution plate installed in the plate reformer of FIG. 1.

3 is a view showing a plate reformer according to a second embodiment of the present invention.

4 is a view showing a plate reformer according to a third embodiment of the present invention.

5 is a block diagram showing a fuel cell system employing a flat reformer according to the present invention.

FIG. 6 is a conceptual view illustrating a polymer electrolyte fuel cell using a polymer electrolyte membrane employable of the fuel cell of FIG. 5.

Explanation of symbols on the main parts of the drawings

10: plate type reformer 11: combustion reaction part

13: reforming reaction unit 20a, 20b: cover

21: heat distribution plate

The present invention relates to a flat type reformer capable of effectively controlling the temperature of each reaction part so that the reaction catalyst can react at an appropriate reaction temperature, and a fuel cell system employing the same.

A fuel cell is a low pollution, high efficiency energy source that converts fuel energy directly into electrical energy. Fuel cells basically use an electrochemical reaction between hydrogen and oxygen. That is, the fuel cell uses electrons generated from the anode as electrical energy, and hydrogen ions pass through the electrolyte and react with oxygen of the cathode to generate water. Such fuel cells are classified into phosphoric acid fuel cells, molten carbonate fuel cells, solid oxide fuel cells, polymer electrolyte fuel cells, alkali fuel cells, and the like, depending on the type of electrolyte used. Each of these fuel cells basically operates on the same principle, but differs in the type of fuel used, operating temperature, catalyst, and electrolyte.

Among them, polymer electrolyte membrane fuel cells (PEMFCs) have significantly higher output characteristics, lower operating temperatures, and faster startup and response characteristics than other fuel cells. It has a wide range of applications, such as transportable power sources such as transportable power sources and automotive power sources, as well as distributed power sources such as stationary power plants in houses and public buildings.

Hydrogen is most suitable for the fuel cell fuel because it is the most reactive in the electrochemical oxidation reaction occurring at the anode electrode of the fuel cell and does not generate pollutants by generating water after reacting with oxygen. However, since hydrogen is hardly present in its natural state, it is obtained by reforming from other raw materials. For example, hydrogen can be obtained from hydrocarbon-based fuels such as gasoline, diesel, methanol, ethanol, natural gas and the like.

A fuel reformer (hereinafter, referred to as a reformer) is a device for generating hydrogen-rich reformed gas from a hydrocarbon-based fuel. Such reformers are classified into reformers of hydrocarbon decomposition, steam reforming, partial oxidation, autothermal reforming, and the like according to reforming methods. Among them, the reformer of the steam reforming method has the advantage of increasing the output of the fuel cell by obtaining a high concentration of hydrogen by the reaction of the hydrocarbon fuel and steam.

In addition, the reformer generates by-products such as carbon monoxide and carbon dioxide during the reforming process, and these by-products may act as harmful substances depending on the type of fuel cell. For example, in low temperature fuel cells such as polymer electrolyte fuel cells and alkaline fuel cells, carbon monoxide acts as a poisoning material for the anode. Therefore, in the reformer for low temperature fuel cells, carbon monoxide should be removed at a predetermined concentration or less. For example, in a steam reforming reformer, the concentration of carbon monoxide should be reduced to 10 ppm or less. In addition, fossil fuels used as reforming fuels contain sulfur, which acts as a hazardous substance that degrades the performance of most fuel cells and must be removed during or after the fuel reforming process.

On the other hand, the reaction temperature range required for each reaction unit of the reformer is different from each reaction catalyst to be installed. For example, the reaction temperature range of steam reforming (SR) reaction varies depending on the type of reforming raw material, and is about 600 ° C. to 900 ° C. for hydrocarbon fuels such as butane and about 250 ° C. to methanol for methanol fuel. 400 ° C. The reaction temperature range of the water gas shift (WGS) reaction, which is one of the processes for removing carbon monoxide, is approximately 200 ° C. to 350 ° C., and the reaction temperature range of the selective CO oxidation (PROX) reaction is about 100 ° C. To 250 ° C. As described above, the reaction temperature range of each reactor in the reformer is lowered in the order of the reforming reactor, the water gas conversion unit, and the selective oxidation unit. Therefore, each reaction part needs to be controlled to have a temperature atmosphere of each reaction temperature range.

In particular, as described above, in the reformer reforming a fuel containing butane, the reaction temperature difference between each reaction section is larger than that of the methanol fuel reformer, so that it is difficult to properly control the reaction temperature of each reaction section. In addition, in the case of using a fuel containing butane in a reformer having a flat plate structure in which each reaction unit is manufactured in a flat shape and stacked, that is, steam reforming of hydrocarbons in the flat reformer is carried out in the reforming reaction unit and the carbon monoxide reducing unit, such as aqueous solution. Since the gas switching unit and the selective oxidizing unit are successively stacked, the reaction temperature difference between these reaction units is large, making it more difficult to control the reaction temperature.

It is an object of the present invention to provide a planar reformer capable of easily controlling the reaction temperature gradient of each reaction section while effectively transferring the reaction heat of the combustion reaction section to the reforming reaction section.

Still another object of the present invention is to provide a flat type reformer capable of steam reforming a fuel containing butane as a main component by employing a structure capable of efficiently adjusting the reaction temperature of each reaction unit.

Still another object of the present invention is to provide a fuel cell system capable of compactly implementing the size of the entire system by using the aforementioned flat type reformer.

In order to achieve the above object, according to the first embodiment of the present invention, an oxidation catalyst layer is located therein, a combustion reaction part generating thermal energy by reaction of a combustion fuel and an oxidant, and a reforming catalyst layer is located therein. And a reforming reaction unit for generating hydrogen-rich reformed gas from the reformed fuel through the reforming reaction by the thermal energy of the combustion reaction unit, and inserted between the combustion reaction unit and the reforming reaction unit, and the combustion reaction unit and the reforming reaction unit. It is installed between the heat distribution plate with higher thermal conductivity than the housing, and the harmful substance removal unit for removing harmful substances contained in the reformed gas, for example, carbon monoxide reduction unit, and between the preheating unit and carbon monoxide reduction unit, and reducing the preheating unit and carbon monoxide reduction unit. A flat type reformer is provided that includes a thermal barrier plate having a lower thermal conductivity than a negative housing.

Preferably, at least one of two surfaces of the combustion reaction unit, the reforming reaction unit, and the combustion reaction unit and the preheating unit facing each other is provided with a recess into which the heat distribution plate and the heat shield plate are respectively inserted. In addition, the housing of the combustion reaction section and the reforming reaction section is made of any one of aluminum and an alloy containing aluminum as a main component. The heat distribution plate comprises at least one of copper, silver, gold, and alloys thereof, or a carbon composite material. The reformed fuel includes a hydrocarbon fuel mainly composed of butane.

In addition, the carbon monoxide reduction unit may include a water gas conversion unit for converting carbon monoxide to hydrogen and carbon dioxide by adding water vapor, and a selective oxidation unit for converting carbon monoxide to carbon dioxide by an oxidation reaction. In addition, at least one of the water gas conversion unit and the selective oxidation unit may include a heat exchanger for controlling the reaction temperature.

According to a second embodiment of the present invention, there is provided a fuel supply device for supplying reformed fuel and combustion fuel containing butane, a reforming device for processing reformed fuel to generate a hydrogen-rich reformed gas, and reforming gas and oxidant electricity The fuel cell includes a fuel cell that generates electrical energy by a chemical reaction, wherein the reforming apparatus includes a plate type combustion reaction unit in which an oxidation catalyst layer is positioned to generate combustion energy by reacting combustion fuel with an oxidant, and thermal energy of the combustion reaction unit. A reforming reaction layer having a reforming catalyst layer for generating a hydrogen-rich reforming gas from the reforming fuel therein is inserted between the combustion reforming unit and the reforming reaction unit, and the combustion reaction unit and the reforming reaction unit. Heat distribution plate with higher thermal conductivity than the housing of the reaction part, and harmful substances to remove harmful substances contained in the reformed gas Rejection, for example, a fuel cell system including a heat shield plate inserted between the preheating unit and the carbon monoxide reducing unit, and having a lower thermal conductivity than the housing of the preheating unit and the carbon monoxide reducing unit is provided.

Preferably, the above described reforming apparatus includes a flat plate reformer according to the first embodiment described above.

In addition, the above-described fuel cell system may further include a pipe for supplying the anode off-gas of the fuel cell to the reforming apparatus as reforming fuel. In addition, the fuel cell system described above may further include a circulation device for supplying the water flowing out from the cathode side of the fuel cell to the reformer. In addition, the fuel cell system described above may further include a water supply device for supplying water to the reformer and the electricity generating unit and an air supply device for supplying air. In addition, the fuel cell system described above may further include a desulfurization apparatus for removing organic sulfur compounds from the reformed fuel containing butane supplied from the fuel supply device to the reformer.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, when a part is combined with another part, this includes not only a case where the part is directly coupled, but also a case where other elements are interposed therebetween. In addition, in the following description, a fuel includes water and air (oxygen) as a broad fuel in addition to narrow fuel containing hydrogen, such as methanol, butane, and natural gas. However, the fuel described below is defined as the fuel of consultation. In the drawings, the thickness or size of each element is exaggerated for clarity and convenience of explanation. In the drawings, like reference numerals refer to similar or identical elements.

1 is a view showing a flat plate reformer according to a first embodiment of the present invention.

Referring to FIG. 1, the planar reformer 10 generates heat by reacting air with fuel off gas (combusted fuel) and / or some fuel of a fuel supply device (not shown) coming from an anode side outlet of a fuel cell. In addition, the reformed gas is generated by steam reforming the mixed fuel in which the fuel (reformed fuel) and water are mixed using the generated heat. At this time, in the plate-type reformer 10 is generated in the combustion reaction unit 11 by installing a heat distribution plate 21 having a higher thermal conductivity than the housing in which the combustion reaction unit 11 and the reforming reaction unit 13 are installed therebetween. The heat is effectively transferred to the reforming reaction unit 13, thereby improving the thermal efficiency of the combustion reaction unit 11 and the reforming efficiency of the reforming reaction unit 13. Here, the combustion reaction part 11 becomes a heat source part, and the reforming reaction part 13 becomes an endothermic part. And the housing is installed in a plate shape.

More specifically, the flat plate reformer 10 described above includes a combustion reaction unit 11, a reforming reaction unit 13, first and second lids 20a and 20b, and a heat distribution plate 21. And the plate-type reformer 10 is made of a laminated structure in which the edge portions of the housings in which the reaction units are installed are bonded or welded together. The housing of the flat plate reformer 10 is made of aluminum or an alloy containing aluminum as a main component having excellent thermal conductivity and workability.

The first and second lids 20a and 20b are provided outside the combustion reaction section 11 and the reforming reaction section 13. The first and second lids 20a and 20b insulate these reaction parts 11 and 13 so that heat generated in the combustion reaction part 11 is effectively transferred to the reforming reaction part 13 side. The first cover 20a includes a first inlet for inflow of fuel and water, a second inlet for inflow of fuel offgas, a third inlet for inflow of air, a first outlet for exhaust gas, and a reformed gas A second outlet for outflow of is provided. Here, the fuel offgas includes, for example, unreacted fuel flowing out of the fuel cell.

The combustion reaction section 11 burns fuel offgas flowing out of the fuel cell stack as fuel and supplies heat to the entire reformer 10. Of course, the combustion fuel supplied through a separate fuel supply device may be used. In addition, the combustion reaction unit 11 may include, for example, a distribution plate (not shown) in which a plurality of distribution holes are formed so as to be distributed evenly after the oxidant is introduced, and the oxidant supplied through the distribution holes of the distribution plate. It may be composed of a combustion plate (not shown) provided with an oxidation catalyst layer so that the fuel reacts to generate thermal energy.

The reforming reaction unit 13 generates a reformed gas from a mixed fuel in which fuel and water are mixed through a steam reforming reaction using a catalyst, for example, a nickel or ruthenium-based catalyst. The reaction formula for generating the reformed gas from the mixed fuel described above is as follows. However, the reaction formula in which methanol is converted to carbon monoxide and hydrogen is omitted.

CH ₃ OH + H ₂ O ⇔ CO ₂ + 3H ₂

In addition, it is preferable that the reforming catalyst layer inserted into the reforming reaction unit 13 is filled with a granular catalyst. In this case, in order to prevent the scattering of the granular catalyst, the outlet of the reforming reaction unit 13 is more preferably provided with a network.

The heat distribution plate 21 is provided between the combustion reaction section 11 and the reforming reaction section 13. The thermal conductivity of the heat distribution plate 21 is higher than the thermal conductivity of the housing in which the combustion reaction section 11 and the reforming reaction section 13 are installed. As the heat distribution plate 21, for example, a material selected from copper, silver, gold, and alloys thereof having a higher thermal conductivity than aluminum or an aluminum alloy used as the housing material of the combustion reaction unit 11 and the reforming reaction unit 13 is selected. Used. Here, the aluminum alloy includes a certain amount of nickel or manganese contained in aluminum. On the other hand, as the heat distribution plate 21, a carbon composite material having a thermal conductivity higher than that of aluminum or an aluminum alloy may be used. In this case, the carbon composite material preferably has heat resistance of, for example, aluminum or higher.

According to the above-described configuration, there is provided a flat type reformer capable of effectively transferring heat energy generated in the combustion reaction unit to the reforming reaction unit to generate hydrogen-rich reformed gas with high reaction efficiency and thermal efficiency.

2A and 2B are perspective views illustrating a heat distribution plate installed in the flat reformer of FIG. 1.

Referring to FIG. 2A, the heat distribution plate 21a is disposed between the heat source portion 11a and the heat absorbing portion 13a and is formed in the heat source portion 11a in contact with the surfaces of the heat source portion 11a and the heat absorbing portion 13a. Heat is efficiently transferred to the heat absorbing portion 13a. Here, the heat distribution plate 21a, the heat source portion 11a, and the heat absorbing portion 13a correspond to the heat distribution plate 21, the combustion reaction portion 11, and the reforming reaction portion 13 described above with reference to FIG.

The heat distribution plate 21a is produced in a plate shape of a predetermined thickness. In order to insert and install the heat distribution plate 21a between the heat source portion 11a and the heat absorbing portion 13a, a first concave portion 12 is provided on the lower surface of the heat source portion 11a, and the heat absorbing portion 13a The second recess 14 is provided on the upper surface. In other words, the heat distribution plate 21a is inserted between the heat source portion 11a and the heat absorbing portion 13a while being inserted into the first recessed portion 12 and the second recessed portion 14. In the above-described structure, the heat source portion 11a and the heat absorbing portion 13a are welded together. In the above-described case, the surface of the heat distribution plate 21a and the bottom surfaces of the first and second recesses 12 and 14 are processed to be flat so as to make uniform contact.

The thickness of the heat distribution plate 21a is adjusted according to the exothermic temperature of the heat source portion 11a and the temperature required by the heat absorbing portion 13a. In addition, the thickness and shape of the heat distribution plate 21a may be appropriately modified according to the temperature gradient of the heat source portion 11a and / or the heat absorbing portion 13a. For example, if the temperature of the fuel inlet portion of the heat absorbing portion 13a is lower than that of other portions, the thickness of the corresponding portion of the heat distribution plate 21a corresponding to the fuel inlet side is made thin or the heat distribution plate 21a is only on the fuel inlet side. Can be used to adjust the temperature gradient. In this case, the first and / or second recesses 12 and 14 are deformed in response to the deformation of the heat distribution plate 21a. According to the above structure, the reforming efficiency by the catalyst is improved by using the catalyst provided in the heat absorbing portion 13a more uniformly.

In addition, in the structure in which the heat distribution plate 21a is inserted into the plate-type reformer, as shown in FIG. 2B, no recess is provided in the lower surface 12a of the heat source portion 11a, and the heat absorbing portion 13a is provided. Only the upper surface of the recess 14a may be installed. In this case, the depth of the concave portion 14a provided on the upper surface of the heat absorbing portion 13a is provided almost equal to the thickness of the heat distribution plate 21a. Of course, according to the present embodiment, a structure in which the concave portion is provided on the lower surface of the heat source portion 11a and the concave portion is not provided on the upper surface of the heat absorbing portion 13a can be applied as opposed to the case described above.

According to the above configuration, by forming a recess in the reaction portions facing each other and inserting a heat distribution plate or a heat shield plate, the reaction temperature of each reaction unit can be controlled to a desired temperature using a heat distribution plate or a heat shield plate, It is possible to solidify the bonding of the reaction part.

3 is a view showing a plate reformer according to a second embodiment of the present invention.

Referring to FIG. 3, the plate reformer 30 reacts heat by reacting fuel and air mainly composed of butane supplied from a fuel off-gas (combusted fuel) and / or a fuel supply device, etc., emitted from an anode side outlet of a fuel cell. And a reformed gas is generated from a fuel mainly based on butane (reformed fuel) through a steam reforming reaction using the generated heat. At this time, in the flat reformer 30, the heat content having a higher thermal conductivity between the combustion reaction sections 31 and 32 and the reforming reaction section 33 than the housing of the combustion reaction sections 31 and 32 and the reforming reaction section 33. Inserting the back plate (41, 42) so that the heat generated in the combustion reaction section (31, 32) is efficiently transmitted to the reforming reaction section (33).

More specifically, the flat plate reformer 30 described above includes the first and second combustion reaction units 31 and 32, the reforming reaction unit 33, the preheating unit 34, the carbon monoxide (CO) reduction unit 36, First and second covers 40a and 40b, first heat distribution plates 41 and 42 and second heat distribution plate 43 are included. And the plate-type reformer 30 is made of a laminated structure in which each of the plate-shaped housings in which each reaction unit is installed is welded. Each housing is made of aluminum or an aluminum-based alloy having excellent thermal conductivity and workability.

The first and second lids 40a and 40b are provided outside the carbon monoxide reduction unit 36 and the second combustion reaction unit 32. The first cover 40a includes a first inlet for inflow of butane and water, a second inlet for inflow of fuel off gas, a third inlet for inflow of air, a first outlet for exhaust gas, and a reformed gas A second outlet for outflow of is provided.

The first and second combustion reaction units 31 and 32 react with the fuel off-gas (combustion fuel) flowing out of the fuel cell stack to generate heat, and supply the generated heat to the entire reformer. Of course, other fuels supplied separately through a fuel supply device (not shown) may be used as the combustion fuel. The first and second combustion reaction sections 31 and 32 are provided on the upper and lower sides of the reforming reaction section 33 to supply a large amount of heat to the reforming reaction section 33 so as to be suitable for the high reforming reaction temperature of the fuel containing butane. Is placed. The first and second combustion reaction units 31 and 32 have a structure in which a combustion catalyst layer (not shown) is filled in a plate-shaped housing.

The reforming reaction unit 33 generates a reformed gas from the mixed fuel through a steam reforming reaction in a temperature atmosphere of 600 ° C. or higher using a catalyst such as a nickel or ruthenium-based catalyst. Here, the mixed fuel refers to a fuel containing butane as a main component and a fuel mixed with water. The reforming reaction formula for generating the reformed gas from the mixed fuel is as follows.

nC ₄ H ₁₀ + 8H ₂ O ⇔ 4CO ₂ + 13H ₂

The reforming reaction section 33 also includes a reforming catalyst layer for generating a reformed gas rich in hydrogen from the mixed fuel. For example, the reforming catalyst layer includes a structure in which a granular catalyst is filled in the housing. In this case, a network is installed at the outlet of the reforming reaction part 33 in order to prevent the scattering of the granular catalyst.

The preheater 34 mixes and preheats fuel and water using heat generated by the combustion reaction units 31 and 32 before fuel and water are supplied to the reforming reaction unit 33. Fuel and water including butane are introduced into the preheater 34 through the first inlet of the first cover 40a.

The first heat distribution plates 41 and 42 transfer heat generated from the first and second fuel reactors 31 and 32 to both sides of the reforming reaction unit 33. By such a configuration, the reaction temperature of the reforming reaction unit 33 is easily increased to a high temperature, for example, 600 ° C to 700 ° C, so that the fuel containing butane can be reformed with high efficiency through the steam reforming reaction. The second heat distribution plate 43 efficiently transfers the heat generated by the first combustion reaction unit 31 and / or the second fuel reaction unit 32 to the preheater 34. As the above-mentioned first and second heat distribution plates 41, 42, 43, for example, at least one material or carbon composite material selected from copper, silver, gold, and alloys thereof having a thermal conductivity higher than that of aluminum or an aluminum alloy. Is used. On the other hand, the above-described heat distribution plate 41, 42, 43 may be installed in one piece or divided into a plurality of pieces. On the other hand, the second heat distribution plate 43 described above may be replaced with a heat shield plate capable of blocking the heat transmitted from the combustion reaction part 31 side to a certain extent when the reaction temperature of the preheater 44 is higher than a desired temperature. Can be. The thermal barrier plate may be another carbon composite material having a lower thermal conductivity than aluminum or an aluminum alloy.

The carbon monoxide reduction unit 36 removes carbon monoxide contained in the reformed gas by a method such as water gas conversion, catalytic reaction, and adsorption. The reaction temperature required for the carbon monoxide reduction unit 36 is controlled by adjusting the structure and thickness of the upper first heat distribution plate 41 and the second heat distribution plate 43. For example, a hole is formed in the upper first heat distribution plate 41 and / or the second heat distribution plate 43 or the thickness is adjusted to control the intensity of heat transferred to the carbon monoxide reduction unit 46.

As described above, in the planar reformer according to the present embodiment, a heat distribution plate is inserted between the housings of the respective reaction units, such that a high reaction temperature, for example, 600 ° C to 700 ° C is uniformly provided to the reforming reaction unit, thereby providing The reforming reaction of butane is performed properly, and a relatively high reaction temperature, such as 350 ° C. to 500 ° C., is provided in the preheating section to effectively mix and preheat the fuel and water in the preheating section, and a relatively low reaction temperature, eg 100 ° C. By providing the carbon monoxide reduction unit at ˜350 ° C., the reaction temperature of each reaction unit can be easily controlled so that the carbon monoxide contained in the reforming gas in the carbon monoxide reduction unit is reduced below a certain concentration. As described above, according to the present invention, each reaction unit is operated at a high reaction efficiency at an appropriate reaction temperature by using a heat distribution plate, thereby providing a flat plate reformer capable of reforming fuel including butane at high reforming efficiency.

According to the above-described configuration, since the combustion reaction section and the reforming reaction section are laminated, the heat transfer path is short and advantageous in terms of thermal efficiency. In addition, by manufacturing the heat source portion and the heat absorbing portion in a laminated structure in the same section, it is possible to realize a compact size of the overall reforming system. In addition, it is possible to provide a flat type reformer that can be suitably applied to steam reformers of hydrocarbons such as butane having a large difference in reaction temperature of each reaction unit.

In addition, in the flat reformer, the temperature gradient of the reforming reaction unit is reduced to allow a relatively uniform catalyst reforming reaction to occur in the reforming reaction unit, thereby increasing the amount of catalyst participating in the reaction, thereby increasing the hydrogen content in the reforming gas. There is an advantage. In addition, since the preheating unit is stacked together, there is no need to preheat separately the fuel supplied to the reformer during the initial operation, thus preventing the problem that the overall efficiency of the system is degraded due to the consumption of energy for preheating.

4 is a view showing a plate reformer according to a third embodiment of the present invention.

Referring to FIG. 4, the planar reformer 30a generates heat by reacting fuel off-gas (combustion fuel) coming from the anode side outlet of the fuel cell with air to generate heat, and generates butane through a steam reforming reaction using the generated heat. The reformed gas is generated from the fuel (reformed fuel) containing the main component. In this case, in the plate-type reformer 30a, the heat distribution plates 41, 42, 43, 44, and 45 are disposed between the plate-shaped housings in which the reaction units 31, 32, 33, 34, 36a, and 36b are installed. Insert and adjust the reaction temperature of each reaction unit appropriately. Here, the heat distribution plate includes a heat shield plate.

The first heat distribution plates 41 and 42 are inserted between the first and second combustion reaction units 31 and 32 and the reforming reaction unit 33. The second heat distribution plate 43 is inserted between the first combustion reaction unit 31 and the preheater 34. The third heat distribution plate 44 is inserted between the preheater 34 and the water gas switching unit 16a. The fourth heat distribution plate 45 is inserted between the water gas switching unit 36a and the selective oxidation unit 36b.

In order to appropriately adjust the reaction temperature of each reaction section, the first heat distribution plates 41 and 42 are made of a material having a higher thermal conductivity than the housing of the first and second combustion reaction sections 31 and 32 and the reforming reaction section 33. Manufactured to a certain thickness and shape. In addition, the second heat distribution plate 43 is made of a material having a higher / lower thermal conductivity than the housing of the first combustion reaction part 31 and the preheating part 34, and is manufactured to have a predetermined thickness and shape. The third heat distribution plate 44 is made of a material having a higher / lower thermal conductivity than the housing of the preheater 34 and the water gas conversion unit 36a, and is manufactured to have a predetermined thickness and shape. In addition, the fourth heat distribution plate 45 is made of a material having a higher / lower thermal conductivity than the housing of the water gas conversion unit 36a and the selective oxidation unit 36b. According to the above configuration, it is possible to easily control the reaction temperature of each reaction unit of the plate-type reformer by using a heat distribution plate having a thermal conductivity higher than the thermal conductivity of the adjacent housing and a heat distribution plate / heat shielding plate having a thermal conductivity lower than the thermal conductivity of the adjacent housing. have.

The water gas shift unit 36a described above reduces the concentration of carbon monoxide contained in the reformed gas through a water gas shift reaction in which carbon monoxide contained in the reformed gas is converted into hydrogen and carbon dioxide by adding water vapor. The water gas shift reaction is controlled by equilibrium so that the reaction composition is determined by temperature and pressure, so that the water gas shift unit maintains the appropriate temperature. For example, in the water gas conversion reaction, the carbon dioxide is generated in the direction of exothermic reaction, which is advantageous at low temperature, while at high temperature, the reverse reaction, which is an endothermic reaction, proceeds to consume hydrogen to generate carbon monoxide. Catalysts for the water gas shift reaction include pyrogenic catalysts usable at temperatures of 500 ° C. or higher, such as Cr ₂ O ₃ / Fe ₃ O ₄ or low temperature catalysts usable at temperatures of 200 ° C. or higher, such as Cu / ZnO / Al ₂ O ₃ and the like can be used. The reaction equation of the water gas shift reaction is as follows.

CO + H ₂ O ⇔ CO ₂ + H ₂

In addition, the water gas switching unit 36a may include a heat exchanger 46 as an auxiliary means for controlling the reaction temperature. For example, the heat exchanger 46 may be a pipe that surrounds the water gas switching unit 36a and circulates with the coolant. According to the above-described configuration, the reaction temperature of the water gas switching unit 36a can be more precisely controlled using the heat distribution plate and the heat exchanger.

The selective oxidation unit 36b described above converts carbon monoxide contained in the reformed gas into carbon dioxide through a selective oxidation reaction of a catalyst that selectively reacts only carbon monoxide. For example, the selective oxidation unit 36b reduces the concentration of carbon monoxide contained in the reformed gas passing through the water gas switching unit 36a to a desired concentration, for example, 10 ppm or less. Catalysts that can be employed in the selective oxidation unit 36b include Ru, Rh, Pt / Al ₂ O ₃ , TiO ₂ , ZrO ₂ , Au / Fe ₂ O _3, and the like. The reaction scheme of the selective oxidation reaction is as follows.

CO + 1 / 2O ₂ → CO ₂

In addition, the selective oxidation unit 36b may include a heat exchanger 47 as an auxiliary means for controlling the reaction temperature. For example, the heat exchanger 47 may be a pipe that surrounds the selective oxidation unit 36b and circulates with the coolant. According to the above-described configuration, it is possible to more precisely control the reaction temperature of the selective oxidation unit 36b by using a heat distribution plate and a heat exchanger.

According to the above-described configuration, it is possible to efficiently control the reaction temperature by using the heat distribution plate in the water gas conversion unit and the selective oxidation unit installed in the same section of the plate reformer. Therefore, it is possible to easily provide a highly efficient plate-type reformer capable of reducing the carbon monoxide contained in the reformed gas to a predetermined amount or less after obtaining the rich reformed gas hydrogenated from the fuel containing butane.

5 is a block diagram showing a fuel cell system employing a flat reformer according to the present invention.

Referring to FIG. 5, a fuel cell system generates electric energy by electrochemically reacting hydrogen-rich reformed gas and oxygen in air from a fuel mainly composed of butane. To this end, the fuel cell system includes a fuel storage container 110, an attachment device 120, a desulfurization device 130, a reforming device 200, a fuel cell 300, and a circulation tank 400. Here, the fuel storage container 110, the attachment device 120 and the desulfurization device 130 constitutes a fuel supply device 100 for supplying a fuel containing high quality butane to the reformer 200. The fuel containing butane as a main component may contain a predetermined amount of propane or odorant.

In more detail, the fuel storage container 110 includes a container in which fuel containing butane as a main component is stored in order to obtain hydrogen used in a fuel cell. For example, the fuel storage container 110 includes a compression storage container in which fuel mainly composed of butane is compressed and stored in the liquid phase by a predetermined pressure. The fuel storage container 110 takes away the heat of condensation of the gaseous substance around the container and releases the fuel containing butane. As the fuel storage container 110, butane cans, which are commercially available, may be used. Butane cans are usually made of a thin tin plated steel sheet and have an internal pressure of about 15 kg / cm 2. In the above-described case, the fuel storage container 110 may include a discharge valve 112 for discharging fuel containing butane, such as butane can. The discharge valve 112 has a structure that opens when the protruding valve is pressed to a predetermined pressure.

Attachment device 120 represents a coupling means for coupling fuel reservoir 110 to reformer 200 side. The attachment device 120 presses the discharge valve 112 at a predetermined pressure when combined with the fuel storage container 110 to discharge the fuel stored in the fuel storage container 110. Accordingly, the fuel storage container 110 and the attachment device 120 are provided with a coupling structure such as a screw coupling structure or a locking step structure, respectively.

For example, the attachment device 120 may include a pressure sensing safety means for allowing the fuel storage container 110 to be separated from the internal pressure of the fuel storage container 110 at 5 kg / cm 2 or more and 7 kg / cm 2 or less. . In addition, the attachment device 120 may be provided with a valve to block the discharge of the fuel in the state in which the fuel storage container 110 is coupled.

The desulfurization apparatus 130 removes harmful substances, such as organic sulfur compounds, contained in the fuel stored in the fuel storage container 110 before the reforming step. The organic sulfur compound is a harmful substance that causes the deactivation of the platinum catalyst or the nickel catalyst used in most fuel cells 300, thereby degrading the performance of the fuel cell 300. The desulfurization apparatus 130 is a desulfurization method using an adsorbent such as activated carbon, a desulfurization method using a metal and metal oxide catalyst such as ZnO-based or Cu / Zn-based materials, or a predetermined amount of hydrogen and natural gas at a temperature of 350 to 400 ° C. The gas may be reacted with an organic sulfur compound to generate hydrogen sulfide, followed by desulfurization.

The reformer 200 generates a reformed gas rich in hydrogen from the fuel supplied from the fuel supply device 100. And reducing harmful substances, such as carbon monoxide, contained in the generated reformed gas. To this end, the reforming apparatus 200 includes a reforming unit 210 and a hazardous substance removing unit 220. Here, the harmful substance removal unit 220 preferably includes a water gas conversion unit and an optional oxidation unit to reduce the carbon monoxide concentration contained in the reformed gas to less than 10 ppm. The reformer 200 or the reformer 210 according to the present embodiment employs the flat type reformer according to the present invention mentioned above. In this case, since the flat plate reformer is advantageous in miniaturization, the fuel cell system can be miniaturized.

In addition, the reforming apparatus 200 may receive the necessary air through the air pump 230 or the blower. In addition, the reforming apparatus 200 uses a fuel off gas flowing out of the anode side of the fuel cell 300 as a combustion fuel of the reforming unit 210 to improve the overall efficiency of the system, The water flowing out from the cathode side of 300 may be reprocessed and used for steam reforming reaction of the reforming unit 210. In addition, the reforming apparatus 200 may receive a portion of the combustion fuel required for the reforming unit 210 directly from the fuel storage container 110 without passing through the desulfurization apparatus 130.

The fuel cell 300 receives the reformed gas rich in hydrogen from the reformer 200, receives air containing oxygen through an air pump (not shown), and the like to generate electrical energy by electrochemically reacting hydrogen and oxygen. Let's do it. The fuel cell 300 then discharges the unreacted fuel and the reaction product. Here, the method of supplying oxygen to the fuel cell 300 is a method of directly supplying pure oxygen gas in addition to the method of using oxygen contained in the air or a method of supplying a fuel containing oxygen that can function as an oxidant in addition to air. have.

As the fuel cell 300 described above, a polymer electrolyte fuel cell in which a polymer membrane having hydrogen ion exchange characteristics is installed may be used. In this case, the fuel cell 300 may be provided with a humidifier for supplying appropriate moisture to the polymer electrolyte membrane for stable operation and improvement of operation efficiency.

The circulation tank 400 is a device into which by-products, for example, water, flows out from the cathode side of the fuel cell 300. Water is condensed while passing through a heat exchanger such as a condenser 410 installed between the fuel cell 300 and the circulation tank 400. The circulation tank 400 stores the liquid fluid in the by-products introduced thereto, and discharges an undesired gaseous fluid such as air or carbon dioxide. The water stored in the circulation tank 400 is supplied to the reformer 200 to be used for the steam reforming reaction. In this case, the overall efficiency of the fuel cell system can be improved.

The above-described circulation tank 400 is provided with, for example, a lower section having an outlet for supplying water to the outside, and an inlet through which the effluent from the cathode is introduced and a vent for venting gas. It may include an upper region. In addition, the above-described circulation tank 400 may be provided between the lower region and the upper region, and may further include a separator for improving the condensation effect by contacting water falling into the lower region with water vapor rising to the upper region. In addition, the above-described circulation tank 400 may be provided with a measuring device for detecting a change in the flow rate of water. In addition, the water stored in the circulation tank 400 may be supplied to the reformer 200 through a filter device including a pretreatment filter, an ion exchange resin filter, and the like. In this case, water can be used for a long time in the fuel cell system.

According to the above structure, even when the reaction temperature difference of each reaction part is large, such as when reforming a fuel containing butane as a main component, by adopting a compact and highly efficient plate type reformer that can easily adjust the reaction temperature of each reaction part, It is possible to improve the overall efficiency of the fuel cell system and contribute to the miniaturization of the fuel cell system.

FIG. 6 is a schematic view of a polymer electrolyte fuel cell employable in the fuel cell system of FIG. 5.

Referring to FIG. 6, the polymer electrolyte fuel cell 300a has a form in which a porous anode and a cathode are attached to both sides of the polymer electrolyte membrane. More specifically, the polymer electrolyte fuel cell 300a includes a polymer electrolyte membrane 301 having hydrogen ion exchange characteristics and an anode electrode 302 attached to both sides of the polymer electrolyte membrane 301 and called a cathode or a fuel electrode. And a cathode electrode 303 called a cathode or cathode. Electrochemical oxidation of hydrogen as a fuel occurs at the anode electrode 302, and electrochemical reduction of oxygen as an oxidant occurs at the cathode electrode 303, and electrical energy is generated due to the movement of electrons generated at this time. The reaction scheme and total reaction formula for each electrode are as follows.

_{Anode: H 2 (g) → 2H} + + 2e -

_{Cathode: 1 / 2O 2 (g)} + 2H + + 2e - → H 2 O (l)

Total reaction equation: H ₂ (g) + 1 / 2O ₂ (g) → H ₂ O (l)

In addition, the polymer electrolyte fuel cell may include a separator (not shown) for constructing a stack. In the above-described case, the stack is a unit cell including a membrane-electrode assembly (MEA) and a separator plate having an anode electrode 302 and a cathode electrode 303 attached to both sides of the polymer electrolyte membrane 301. dozens, hundreds of cells) are stacked.

The polymer electrolyte fuel cell described above has the characteristics of high efficiency, high current density and high output density, short start-up time and fast response to load changes. And because it can produce a wide range of output, it can be applied to a wide variety of fields, such as power source of pollution-free vehicle, on-site power generator, mobile power.

As mentioned above, although preferred embodiment of this invention was described in detail, this invention is not limited to the said embodiment, A various deformation | transformation by a person of ordinary skill in the art within the scope of the technical idea of this invention is carried out. This is possible.

According to the above-described configuration, the reaction efficiency can be improved by increasing the thermal conductivity between the reaction units in the plate reformer. In addition, by inserting a material having a different thermal conductivity between each of the reaction units, the reaction temperature of each reaction unit can be appropriately controlled by increasing or decreasing the thermal conductivity between the respective reaction units. In particular, there is an advantage that the reaction temperature of each reaction unit can be appropriately controlled even when the reaction temperature difference between the reaction units is large, such as steam reformers of hydrocarbons such as butane. In addition, it is possible to provide a miniaturized flat type reformer that can be easily applied to a fuel cell system using butane fuel gas.

Claims (21)

An oxidation catalyst layer disposed therein, and a combustion reaction unit generating thermal energy by reacting combustion fuel with an oxidant; A reforming reaction unit having a reforming catalyst layer disposed therein and generating a reformed gas rich in hydrogen from the reforming fuel through a reforming reaction by thermal energy of the combustion reaction unit; A heat distribution plate inserted between the combustion reaction unit and the reforming reaction unit and having a higher thermal conductivity than a housing of the combustion reaction unit and the reforming reaction unit; A preheating unit having a channel through which the reformed fuel and water are introduced therein and preheating the reformed fuel and the water by thermal energy of the combustion reaction unit; And And a heat shield plate inserted between the preheater and the combustion reaction part, the heat shield having a lower thermal conductivity than the housing of the preheater. The method of claim 1, And a concave portion into which the heat distribution plate is inserted in at least one of two surfaces of the combustion reaction unit and the reforming reaction unit facing and joined to each other. The method of claim 1, And a concave portion into which the heat shield plate is inserted, at least one of two surfaces of the combustion reaction portion and the preheating portion facing and joined to each other. The method of claim 1, And said housing is made of a material of any one of aluminum and an alloy containing aluminum as a main component. The method of claim 4, wherein Wherein said heat distribution plate is made of at least one of copper, silver, gold and alloys thereof, or a carbon composite material, and the heat shield plate is made of a carbon composite material. The method of claim 4, wherein The reforming fuel is a flat reformer that is a hydrocarbon fuel including butane. The method of claim 6, A carbon monoxide reduction unit for reducing carbon monoxide contained in the reforming gas to a predetermined content or less; And And a second heat shield plate inserted between the preheating unit and the carbon monoxide reducing unit, the second heat shield having a lower thermal conductivity than a housing of the preheating unit and the carbon monoxide reducing unit. The method of claim 7, wherein The carbon monoxide reducing unit includes a water gas conversion unit for converting carbon monoxide to hydrogen and carbon dioxide by adding steam, and a selective oxidation unit for converting carbon monoxide to carbon dioxide by an oxidation reaction. The method of claim 8, At least one of the water gas conversion unit and the selective oxidation unit comprises a heat exchanger for controlling the reaction temperature. A fuel supply device for supplying reformed fuel and combustion fuel; A reformer for treating the reformed fuel to produce a reformed gas rich in hydrogen; And It includes a fuel cell for generating electrical energy by electrochemically reacting the reforming gas and the oxidant, The reforming apparatus includes: a combustion reaction unit in which an oxidation catalyst layer is positioned inside such that the combustion fuel and the oxidant react to generate thermal energy; A reforming reaction unit having a reforming catalyst layer for generating a reformed gas rich in hydrogen from the reforming fuel through a reforming reaction by thermal energy of the combustion reaction unit; A heat distribution plate inserted between the combustion reaction unit and the reforming reaction unit and having a higher thermal conductivity than a housing of the combustion reaction unit and the reforming reaction unit; A preheating unit having a channel through which the reformed fuel and water are introduced therein and preheating the reformed fuel and the water by thermal energy of the combustion reaction unit; And a heat shield plate inserted between the preheating unit and the combustion reaction unit and having a lower thermal conductivity than the housing of the preheating unit. The method of claim 10, The housing of the combustion reaction unit and the housing of the reforming reaction unit have at least one of two surfaces facing each other with a first concave portion into which the heat distribution plate is inserted, and the housing of the preheating unit and the housing of the combustion reaction unit face each other. At least one of the two surfaces of the fuel cell system is provided with a second concave portion is inserted into the heat shield plate. The method of claim 11, wherein The housing is made of any one of aluminum and an aluminum-based alloy, the heat distribution plate is made of at least one material or carbon composite material of copper, silver, gold and their alloys, and the heat shield plate is a composite material Fuel cell system consisting of. The method of claim 12, The reformed fuel is a fuel cell system including a hydrocarbon fuel including butane. The method of claim 10, A carbon monoxide reduction unit for reducing carbon monoxide contained in the reformed gas; And And a second heat shield plate inserted between the preheating unit and the carbon monoxide reducing unit and having a lower thermal conductivity than a housing of the preheating unit and the carbon monoxide reducing unit. The method of claim 14, The carbon monoxide reducing unit may include: a water gas converting unit converting carbon monoxide into hydrogen and carbon dioxide by adding steam; And a selective oxidation unit converting carbon monoxide to carbon dioxide by an oxidation reaction. The method of claim 15, At least one of the water gas conversion unit and the selective oxidation unit has a heat exchanger for controlling a reaction temperature. The method of claim 10, And a pipe for supplying the anode off-gas of the fuel cell to the reforming device as the reforming fuel. The method of claim 10, And a circulation device for supplying the reformer with water flowing out from the cathode side of the fuel cell. The method of claim 10, And a water supply device for supplying water to the reformer, the electricity generator, and an air supply device for supplying air. The method of claim 10, And a desulfurization device for removing organic sulfur compounds from the butane-containing reformed fuel supplied from the fuel supply device to the reformer. The method of claim 10, The fuel cell is a polymer electrolyte fuel cell having a polymer electrolyte membrane.

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