JP2005183216A - Burner for reformer and fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a miniaturizable burner for a reformer while inhibiting pressure loss, and a miniaturized fuel cell system having little pressure loss. <P>SOLUTION: This burner for a reformer for providing heat for reforming reaction to a reformer obtaining reformed gas containing hydrogen by reforming material for hydrogen production for the fuel cell system comprises only two gas passages not connected to each other, wherein a gas entrance of a first gas passage is an oxygen-containing gas inlet for introducing oxygen-containing gas and a gas exit of the first gas passage includes a burner mat. The first gas passage includes a liquid fuel nozzle for forcing the liquid fuel to flow downward into the first gas passage, and a heating surface for vaporizing the liquid fuel flown downward. The gas entrance of the second gas passage is a hydrogen pole off gas inlet for introducing hydrogen pole off gas of a fuel cell, and the gas exit of the second gas passage includes a hydrogen off gas nozzle for providing the hydrogen pole off gas toward downstream of the burner mat. The fuel cell system includes this burner for a reformer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fuel cell system. The present invention also relates to a burner for supplying heat necessary for a reformer used in a fuel cell system.

  In a small burner that uses liquid fuel as a fuel, such as used in a reformer of a fuel cell system, it is difficult to diffuse and burn the fuel by pressure spraying. For this reason, in such a burner, after vaporizing the fuel, it is mixed with air (primary air) and then burned using a burner head having a plurality of flame holes.

In order to vaporize the liquid fuel, the liquid fuel is generally supplied dropwise to a cup-like container heated by an electric heater, called a vaporizer, which is heated to a temperature sufficient to vaporize the liquid fuel. In contact with the heated surface (inner wall of the container). Then, the air supplied to the burner was divided into primary air and secondary air, and first, an air-fuel mixture of primary air and vaporized liquid fuel was formed and burned, and the unburned residue was completely burned by the secondary air. . In addition, the burner used in the fuel cell system has a structure in which a hydrogen electrode offgas nozzle is provided in the vicinity of the burner head for burning the liquid fuel to burn off the hydrogen electrode offgas, and the offgas can also be combusted. Such a structure of the burner for liquid fuel is described in, for example, Japanese Patent Application Laid-Open No. 7-237902.
JP 7-237902 A

  In such a small burner for a fuel cell, since the hydrogen electrode off-gas of the fuel cell contains hydrogen having a wide explosion range, premixing with air is not preferable from the viewpoint of preventing flashback. Therefore, a passage through which the off gas communicating with the off gas nozzle flows is required in addition to the air flow path inside the burner. Therefore, in the burner having a structure represented by Patent Document 1, it is necessary to divide the interior of the burner into at least three spaces to form a gas passage through which primary air flows, a gas passage through which secondary air flows, and a gas passage through which off-gas flows. there were. For this reason, improvements have been desired in that the structure is complicated, it is difficult to reduce the size, and the sectional area of the flow path is reduced due to space subdivision and the pressure loss is increased.

  An object of the present invention is to provide a reformer burner that has a simpler structure and can be miniaturized while suppressing pressure loss. Another object of the present invention is to provide a compact fuel cell system with low pressure loss.

According to the present invention, in a reformer burner for supplying heat for reforming reaction to a reformer used in a fuel cell system to obtain a reformed gas containing hydrogen by reforming a raw material for hydrogen production. ,
Have only two gas flow paths that do not communicate with each other,
The gas inlet of the first gas channel is an oxygen-containing gas inlet for introducing the oxygen-containing gas, the gas outlet of the first gas channel is provided with a burner mat, and the first gas channel is the first gas channel A liquid fuel nozzle for flowing the liquid fuel into the gas flow path, and a heating surface for vaporizing the flowed liquid fuel,
The gas inlet of the second gas channel is a hydrogen electrode off-gas inlet for introducing the hydrogen electrode off-gas of the fuel cell, and the hydrogen electrode off-gas is supplied downstream of the burner mat to the gas outlet of the second gas channel. A reformer burner comprising a hydrogen electrode off-gas nozzle is provided.

  In the burner, the burner mat is preferably made of a woven or non-woven metal fiber.

  The burner preferably further includes a control means for controlling the combustion air ratio based on the liquid fuel to 1.5 or less.

In the burner, it is preferable that the combustion amount of the liquid fuel per unit area of the burner mat is 200 kW / m ² or more and 4500 kW / m ² or less.

  In the burner, it is preferable that the combustion amount based on the liquid fuel is 8.1 kW or less.

According to the present invention, in a fuel cell system comprising a reformer for reforming a raw material for hydrogen production to obtain a reformed gas containing hydrogen, and a fuel cell using the reformed gas as fuel,
The reformer comprises a reformer burner for supplying heat for the reforming reaction;
The reformer burner has only two gas flow paths that do not communicate with each other,
The gas inlet of the first gas channel is an oxygen-containing gas inlet for introducing the oxygen-containing gas, the gas outlet of the first gas channel is provided with a burner mat, and the first gas channel is the first gas channel A liquid fuel nozzle for flowing the liquid fuel into the gas flow path, and a heating surface for vaporizing the flowed liquid fuel,
The gas inlet of the second gas channel is a hydrogen electrode off-gas inlet for introducing the hydrogen electrode off-gas of the fuel cell, and the hydrogen electrode off-gas is supplied downstream of the burner mat to the gas outlet of the second gas channel. A fuel cell system comprising a hydrogen electrode off-gas nozzle is provided.

  In the burner of the present invention, all supplied oxygen-containing gas (for example, air) is led into the vaporizer in the first flow path, preheated in contact with the vaporizer, and mixed with the vaporized liquid fuel. And become a flammable mixture. The air-fuel mixture is guided to a burner mat installed downstream of the vaporizer, and forms a flame on the burner mat surface and / or below to burn. Since secondary air is unnecessary, the space inside the burner covered with the casing is only divided into two passages, one for oxygen-containing gas or combustible gas mixture and the other for hydrogen electrode off-gas. Therefore, the structure is simplified, the size can be easily reduced, the channel cross-sectional area can be relatively large, and the pressure loss can be suppressed.

  Since the fuel cell system of the present invention includes such a burner, it can be made compact as a whole, and pressure loss can also be suppressed.

  As the liquid fuel, a combustible substance that is liquid at normal temperature and normal pressure (25 ° C., 0.101 MPa) can be used as appropriate. For example, compounds having carbon and hydrogen in the molecule such as hydrocarbons and alcohols can be used. Preferable examples that can be obtained at low cost for industrial use or consumer use include methanol, ethanol, gasoline, kerosene, and light oil. Of these, kerosene is preferable because it is easily available for industrial use and consumer use, and is easy to handle.

  Air (atmosphere) is preferable as the oxygen-containing gas used for combustion in the burner, but oxygen-enriched air with an increased oxygen concentration can also be used, and in the fuel cell system, the air electrode of the fuel cell is used. The cathode off-gas discharged from the (cathode) can also be used.

  Hereinafter, although the form of this invention is demonstrated using drawing, this invention is not limited to these. Further, air will be described as an example of the oxygen-containing gas.

  FIG. 1 shows an embodiment of the burner of the present invention. The burner casing 1 basically has a cylindrical shape having a central axis in the vertical direction, and an upper portion serves as a connecting portion 1a for supplying gas or liquid fuel and for mounting an electric heater 9.

  There are only two gas flow paths provided in the burner, the first gas flow path 10 and the second gas flow path 20. The gas inlet of the first gas channel is only the air inlet 11. That is, the only gas supplied to the first gas flow path is air. The number of air inlets can be selected as appropriate, but one is preferable for a simpler structure.

  In the first flow path, the liquid fuel nozzle 12 is provided substantially vertically downward so that liquid fuel can flow into the first flow path from the outside. A heating surface 13 is provided substantially horizontally below the liquid fuel nozzle. The heating surface is formed integrally with the vaporizer 2 and can be heated to a temperature suitable for vaporizing the liquid fuel by heat conduction from the electric heater 9 embedded in the vaporizer.

  The liquid fuel flowing down from the liquid fuel nozzle comes into contact with the heating surface 13 and vaporizes. The liquid fuel may be dropped intermittently from the nozzle, but it is preferable that the liquid fuel is continuously flowed from the viewpoint of making the concentration of the fuel in the air-fuel mixture more constant. From the viewpoint of stably and continuously flowing down the liquid fuel, it is preferable that the discharge speed of the liquid fuel from the nozzle is 5 cm / second or more. Moreover, it is preferable to set it as 60 cm / sec or less from a viewpoint of the pressure loss of liquid feeding. In order to adjust the discharge speed in this way, the flow rate of the liquid fuel may be adjusted by a flow rate adjusting means such as a flow rate adjusting valve or a metering pump and then supplied to the liquid fuel nozzle.

  Although the liquid fuel nozzle can be provided in a direction other than substantially vertically downward, for example, horizontally, the nozzle itself is substantially vertical from the viewpoint of suppressing the formation of relatively large droplets and making the fuel concentration in the mixture more constant. It is preferable to face downward. “Substantially vertically downward” means that the extending direction of the nozzle does not necessarily have to be strictly vertically downward, and the deviation from the vertically downward is preferably within 10 °, more preferably within 5 °. Preferably, it is more preferably within 3 °.

  At least at the tip of the liquid fuel nozzle, the liquid fuel nozzle is in the air flow path, and the liquid fuel nozzle and the air flow direction are preferably in the same direction, and the liquid fuel nozzle and the air flow path are coaxial. More preferably. For example, as shown in FIG. 1, the tip of the liquid fuel nozzle faces vertically downward, and the nozzle tip is disposed in a cylindrical air flow path facing vertically downward, and the center axis of this cylinder coincides with the center axis of the nozzle. The structure which does is preferable. This is because the air flow has the effect of removing the liquid fuel from the nozzle tip, suppresses the large growth of droplets at the nozzle tip, and the liquid fuel concentration in the mixture becomes more constant. .

  The heating surface is preferably substantially horizontal in order for the dropped liquid fuel to diffuse uniformly. “Substantially horizontal” means that the heating surface does not necessarily have to be exactly horizontal, and the deviation from the horizontal is preferably within 10 °, more preferably within 5 °, and more preferably within 3 °. More preferably.

  In addition, the heating surface is preferably circular so that the liquid fuel after dripping diffuses uniformly.

  The heating surface can also be formed integrally in the vaporizer. For example, a hollow cylindrical portion that forms the outer wall of the vaporizer and a plate-like portion that forms the heating surface can be formed integrally. Alternatively, for example, a plate member having a surface to be a heating surface can be joined to a hollow cylindrical member or the like by welding or the like. The vaporizer can have a portion for embedding the heater, a convex portion, or the like.

  The material of the vaporizer is preferably a metal from the viewpoint of thermal conductivity. For example, aluminum or brass is suitable.

  The temperature of the heating surface can be appropriately set according to the type of liquid fuel to be supplied. For example, when the liquid fuel is kerosene, it is preferably 180 ° C. or higher and 250 ° C. or lower, more preferably 190 ° C. or higher and 220 ° C. or lower. This is disadvantageous in that it is near the initial distillation temperature of kerosene below 180 ° C., so the vaporization rate of the high boiling point component is slow, the fuel concentration in the mixture tends to be unstable, and the flame tends to become unstable. In addition, when the temperature exceeds 250 ° C., the dropped liquid droplet is covered with vaporized fuel vapor, so that a so-called film boiling state occurs, the vaporization speed becomes slow, the fuel concentration in the mixture becomes unstable, and the flame becomes unstable. This is disadvantageous in that it tends to be, and this is to avoid such a situation.

  Combustion air collides with the heating surface while mixing with the vaporized liquid fuel. The flow path of the air-fuel mixture of combustion air and liquid fuel turns 90 ° on the heating surface and becomes horizontal along the heating surface, and then turns 90 ° again by the side wall of the carburetor 2. Passes through the gap 14 between the heating surface and the vaporizer sidewall. The flow path of the air-fuel mixture is turned 90 ° by the convex portion 3 of the vaporizer and further turned 90 ° by the vaporizer side wall so as to face downward. In this way, the flow of the air-fuel mixture is changed four times, thereby promoting the mixing of the air and the vaporized liquid fuel. The direction change of four times is not necessarily required and the angle of the direction change may not necessarily be 90 °. However, from the viewpoint of promoting the mixing, the flow path of the air-fuel mixture is preferably changed at least once. More preferably, the direction is changed more than once. In addition, the number of times of changing the direction of the air-fuel mixture is preferably 4 times or less from the viewpoint of suppressing the complexity of the apparatus. In FIG. 1, white arrows indicate the flow direction of the air-fuel mixture.

  It is preferable that the gaps serving as the air-fuel mixture flow path in the carburetor are arranged approximately symmetrically from the viewpoint of preventing the drift of the mixed air flow.

  The air-fuel mixture passes through the extension cylinder 4 and the rectifier 5 which are connected to the downstream side of the vaporizer and form a part of the first flow path inside, and a burner mat 6 is provided. It reaches the outlet of the first channel. The extension cylinder and the rectifier provided on the upstream side of the burner mat are for adjusting the flow of the air-fuel mixture supplied to the burner mat and making the combustion uniform. The vaporizer is also heated by the combustion heat of the burner mat, but by providing an extension cylinder, the distance between the burner mat and the vaporizer can be adjusted, and the temperature control of the vaporizer, particularly the heating surface, is easy. It can also be. In the rectifier, the horizontal cross-sectional area gradually increases toward the bottom, and the opening at the lower end is substantially the same as the shape of the burner mat. The rectifier has a funnel shape as a whole.

  In order to improve combustion stability, a flame holder can be provided on the downstream side of the burner mat.

  The electric heater 9 has a function of supplying heat for preheating the combustion air in addition to supplying heat for vaporizing the liquid fuel. The combustion air is preheated by heat exchange with a vaporizer or the like. In some cases, it is possible to preheat the fuel air separately before supplying it to the burner. When the combustion air is sufficiently preheated separately, it is possible to eliminate the electric heater for heating the vaporizer, but it is preferable to use an electric heater as a heating means from the viewpoint of temperature controllability. A thermocouple (not shown) for measuring the temperature of the vaporizer can be provided as appropriate in order to control the temperature of the heating surface within an appropriate range by operating the output of the electric heater.

  The combustible mixed gas derived from the burner mat can be appropriately ignited and burned by the igniter 8 or the like. It is preferable that the derived direction of the mixed gas is vertically downward. In this case, since the flame is also formed vertically downward, the burner can be placed on the upper part of the reformer or the like to which the burner is attached, and the burner is placed on the lower part of the reformer or the like This is because access to the burner is facilitated during maintenance, and space can be saved while ensuring good maintainability as a whole reformer.

  By burning the mixed gas using the burner mat, the combustion stability is excellent even if the combustion amount is small. For this reason, it is possible to completely burn the fuel without supplying the air in two stages, that is, all the supplied air is mixed with the vaporized liquid fuel and no air is supplied to the other. it can.

As the burner mat, a non-woven fabric or woven fabric of metal fibers, or a non-woven fabric or woven fabric of fibers made of ceramics such as cordierite, titania, mullite, alumina, silica, and alumina-silica can be used. From the viewpoint of heat uniformity and prevention of backfire, a mat made of woven or non-woven metal fibers is preferable as the burner mat. In addition, when the burner mat is a woven fabric or a non-woven fabric, since the opening ratio is larger than that of a punching plate or the like, the speed of the air-fuel mixture when passing through the burner mat becomes slow. For this reason, for example, in a low combustion region of about 200 kW / m ² , a flame is formed in the vicinity of the burner mat, and the burner mat is immediately red hot by the flame, so that good combustion stability is obtained. In addition, in a high combustion range of, for example, about 4500 kW / m ^2, the speed of the air-fuel mixture passing through the burner mat is relatively slow, so that flame blow-off can be suppressed.

Combustion amount of vaporized liquid fuel per unit area of the burner mat, preferably 200 kW / m ² or more in terms of combustion stability, and more preferably from 600 kW / m ² or more, 1000 kW / m ² or more is more preferable. Further, from the viewpoint of the flame blown off suppression, preferably 4500kW / m ² or less, more preferably 4000 kW / m ² or less, more preferably 3500kW / m ² or less. Therefore, a burner mat having an area suitable for realizing such a range with respect to the combustion amount range required by the reformer may be provided.

  The burner of the present invention is particularly suitable for a burner with a small combustion amount. This is because a burner of a type in which liquid fuel is vaporized by a heating surface and burned is suitable for a burner with a small combustion amount, and particularly combustion with a burner mat can be stably burned even with a small combustion amount. This is also because there is a strong demand for compactness in such a small combustion amount burner. Specifically, the effect of the present invention is remarkable in a burner having a maximum combustion amount based on liquid fuel of 8.1 kW (7000 kcal / h) or less, and further in a burner having 5.8 kW (5000 kcal / h) or less. It is.

  Here, the combustion air ratio of the burner will be described with reference to FIG. 3 (FIG. 3 will be described in detail later). In the burner 101, the air ratio based on the liquid fuel is preferably 1.8 or less, more preferably 1.5 or less, and further preferably 1.3 or less. This is because the burner mat is well red hot, the flame is stabilized by the radiant heat from the burner mat, and complete combustion can be performed more reliably. In order to completely burn the liquid fuel, the air ratio is preferably 1.0 or more, more preferably 1.1 or more, and further preferably 1.2 or more. As the means for controlling the air ratio itself, a known flow rate control technique can be used. For example, it is assumed that the flow rate of the liquid fuel is controlled by the flow meter 121, the flow rate regulator 122, and the flow rate control valve 123, and a signal corresponding to the flow rate detected by the flow meter 121 is sent to the arithmetic processing unit 111 such as a computer. The required air flow rate is calculated from the flow rate of the liquid fuel and a preset air ratio, and a signal corresponding to the air flow rate is sent to the flow controller 132 on the air side. The flow control valve 133 can also be used for control.

  The burner of the present invention is used by being mounted on a reformer in a fuel cell system. From the viewpoint of effectively using the hydrogen electrode off-gas of the fuel cell (the hydrogen electrode of the fuel cell, ie, the combustible gas discharged from the anode), the hydrogen electrode off-gas is supplied downstream of the burner mat 6 and burned. The hydrogen electrode off gas is supplied to the burner from the hydrogen electrode off gas inlet 21 which is the inlet of the second flow path 20. The hydrogen electrode off-gas passes through the gap between the vaporizer 2 and the outer burner casing 1 and flows downstream from the hydrogen electrode off-gas nozzle 22 provided at the outlet of the second channel (on the flame holding surface side). That is, it is supplied to the surface side opposite to the first flow path. The burner preferably has a structure in which the hydrogen electrode off-gas can be ignited by the flame of the liquid fuel formed downstream of the burner mat, but the liquid fuel may be blown off by excessive off-gas injection at the time of switching. For this reason, it is desirable that the hydrogen electrode off-gas nozzle be installed at a position where the hydrogen electrode off-gas can be ignited by the igniter 8 for igniting the liquid fuel mixture. Further, as described above, since the hydrogen electrode off gas contains, for example, 20 mol% to 50 mol% of hydrogen that tends to form an explosive mixture, diffusion combustion without premixing with air is preferable. A structure for direct ejection is preferred. In FIG. 1, the black arrows indicate the flow direction of the hydrogen electrode off-gas. Air for burning the hydrogen electrode off gas is supplied downstream of the burner mat via the first flow path. The above-mentioned igniter 8 can also be used to ignite the hydrogen electrode off-gas.

  When burning the hydrogen electrode off-gas, it is not necessary to supply the liquid fuel to the first flow path. However, in some cases, the liquid fuel is supplied to the first flow path, and both the liquid fuel and the hydrogen electrode off-gas are mixed. It can also be burned at the same time.

  As a method of using such a burner, for example, the electric heater 9 is operated to heat the heating surface, and the air is boosted by a gas boosting means such as a blower as needed and supplied from the combustion air inlet 11. After the heating surface 13 reaches a predetermined temperature, the liquid fuel is boosted by a liquid boosting means such as a pump as needed to cause the liquid fuel to flow down from the liquid fuel nozzle 12 and the ignition means such as the igniter 8 is operated. Just do it. When burning the hydrogen electrode off-gas, the hydrogen electrode off-gas can be boosted by a gas booster such as a blower and supplied to the hydrogen electrode off-gas inlet 21 as necessary.

[Reformer]
FIG. 2 shows an example in which this burner 101 is attached to a reformer 102 used in a fuel cell system. The burner is attached to the top of the reformer and is accessible from above.

  The reformer is an apparatus for producing a reformed gas containing hydrogen by reacting a raw material for hydrogen production with water and / or oxygen. In this apparatus, the raw material for hydrogen production is mainly decomposed into hydrogen and carbon monoxide. Usually, carbon dioxide and methane are also contained in the cracked gas. Examples of the decomposition reaction include a steam reforming reaction and an autothermal reforming reaction. The steam reforming reaction involves a large endotherm, and a burner or the like is used to supply heat for this purpose from the outside. Even in the autothermal reforming reaction, heat may be supplied from the outside in some cases. The burner of the present invention can be suitably used for a so-called external heat reformer that supplies heat to the reforming reaction region from the outside. Inside the reformer, a reforming tube 102a containing a catalyst capable of promoting a reforming reaction such as a steam reforming reaction is disposed inside, and this reforming tube is heated by the combustion heat of the burner, and the reforming reaction is performed. Heat is supplied to advance the process.

  The raw material for hydrogen production can be appropriately selected from substances that can obtain a reformed gas containing hydrogen by a steam reforming method or an autothermal reforming method. For example, compounds having carbon and hydrogen in the molecule such as hydrocarbons, alcohols and ethers can be used. Preferable examples that can be obtained inexpensively for industrial use or consumer use include methanol, ethanol, dimethyl ether, city gas, LPG (liquefied petroleum gas), gasoline, kerosene and the like. Of these, kerosene is preferable because it is easily available for industrial use and consumer use, and is easy to handle. The liquid fuel supplied to the burner may be different from the raw material for hydrogen production, but it is preferable to use the same one from the viewpoint of making the entire fuel cell system compact. This is because a storage means such as a tank for these and a supply system such as a pump can be used together.

The steam reforming reaction is a reaction between steam and hydrocarbons, but usually involves heating from the outside because it involves a large endotherm. Usually, the reaction is carried out in the presence of a metal catalyst typified by a Group VIII metal such as nickel, cobalt, iron, ruthenium, rhodium, iridium and platinum. The reaction temperature can be 450 ° C to 900 ° C, preferably 500 ° C to 850 ° C, more preferably 550 ° C to 800 ° C. The amount of steam introduced into the reaction system is defined as the ratio of the number of moles of water molecules to the number of moles of carbon atoms contained in the raw material for hydrogen production (steam / carbon ratio), and this value is preferably 0.5-10. Preferably it is 1-7, More preferably, it is 2-5. When the raw material for hydrogen production is liquid, the space velocity (LHSV) at this time is A / B when the flow rate in the liquid state of the raw material for hydrogen production is A (L / h) and the volume of the catalyst layer is B (L). This value is preferably set in the range of 0.05 to 20 h ⁻¹ , more preferably 0.1 to 10 h ⁻¹ , and still more preferably 0.2 to 5 h ⁻¹ .

  Autothermal reforming is a method of reforming while maintaining a balance of reaction heat by advancing the steam reforming reaction with the heat generated at this time while oxidizing part of the raw material for hydrogen production. In recent years, it has attracted attention as a method for producing hydrogen for fuel cells because it has a short start-up time and is easy to control. Also in this case, the reaction is usually carried out in the presence of a metal catalyst, typically a Group VIII metal such as nickel, cobalt, iron, ruthenium, rhodium, iridium and platinum. The amount of steam introduced into the reaction system is preferably 0.3 to 10, more preferably 0.5 to 5, and still more preferably 1 to 3 as a steam / carbon ratio.

  In autothermal reforming, oxygen is added to the raw material in addition to steam. The oxygen source may be pure oxygen, but in many cases air is used. Usually, oxygen is added to such an extent that it can generate an amount of heat that can balance the endothermic reaction associated with the steam reforming reaction, but the amount added is appropriately determined in relation to heat loss and the amount of external heating by the burner. The amount is preferably from 0.05 to 1, more preferably from 0.1 to 0.75, even more preferably as the ratio of the number of moles of oxygen molecules to the number of moles of carbon atoms contained in the raw material for hydrogen production (oxygen / carbon ratio). Is set to 0.2 to 0.6. The reaction temperature of the autothermal reforming reaction is set in the range of 450 ° C. to 900 ° C., preferably 500 ° C. to 850 ° C., more preferably 550 ° C. to 800 ° C., as in the case of the steam reforming reaction. When the raw material for hydrogen production is liquid, the space velocity (LHSV) at this time is preferably selected in the range of 0.1 to 30, more preferably 0.5 to 20, and still more preferably 1 to 10.

  To control the reaction temperature, for example, the temperature of the reaction region is detected by a thermocouple, etc., the amount of liquid fuel supplementarily supplied to the burner is increased, the combustion air is increased, the hydrogen in the fuel cell Means such as increasing or decreasing the amount of hydrogen contained in the hydrogen electrode off-gas by changing the amount used is used.

[Fuel cell system]
Further, FIG. 3 shows an outline of an example of a fuel cell system having a reformer equipped with the burner. The fuel cell system includes a burner 101, a reformer 102 that performs a steam reforming reaction using the combustion heat of the burner 101, and a fuel in which a reformed gas containing hydrogen obtained by the reformer is supplied to a hydrogen electrode. A battery 103 is included.

  As the fuel cell 103, a fuel cell of a type in which hydrogen is a reactant of electrode reaction at the hydrogen electrode can be appropriately employed. For example, a fuel cell of a solid polymer type, a phosphoric acid type, a molten carbonate type, or a solid oxide type can be employed.

  For example, a solid polymer fuel cell is composed of a hydrogen electrode (anode) 103a and an air electrode (cathode) 103c and a solid polymer electrolyte sandwiched between them, and a reformed gas (hydrogen-containing gas) is placed on the hydrogen electrode side. An oxygen-containing gas such as air is introduced to the pole side after appropriate humidification treatment if necessary. Since a combustible component remains in the hydrogen electrode off-gas discharged from the hydrogen electrode, the hydrogen electrode off-gas is supplied to the burner 101 and burned.

  When the fuel cell system is started, the liquid fuel is vaporized and burned with combustion air, and this heat can be used to warm up the reformer and other devices. After the start-up, the hydrogen off-gas is burned in the burner and the liquid fuel does not have to be burned. In some cases, the hydrogen electrode off-gas and the liquid fuel can be combusted simultaneously.

  Various devices that can be used in the fuel cell system can be provided as appropriate. For example, a reforming gas line between the reformer 102 and the fuel cell 103 can be provided with a CO shift reactor that reduces the CO concentration in the reformed gas and a selective oxidation reactor that further reduces the CO concentration. . A desulfurizer that reduces the concentration of sulfur in the raw material for hydrogen production can also be provided upstream of the reformer. In addition to this, a means for supplying oxygen-containing gas such as air to the air electrode of the fuel cell, a steam generator for generating steam for humidifying the gas supplied to the fuel cell, and various devices such as the fuel cell are cooled. Cooling system, pressurizing means such as pumps, compressors and blowers for pressurizing various fluids, flow regulating means such as valves for regulating the flow rate of fluids, or shutting off / switching the flow of fluids Channel shut-off / switching means, heat exchanger for heat exchange / recovery, vaporizer for vaporizing liquid, condenser for condensing gas, heating / heat-retaining means for externally heating various devices with steam, etc. Examples include storage means, instrumentation air and electrical systems, control signal systems, control devices, and output and power electrical systems.

  The reformer burner of the present invention can be easily miniaturized, and can be suitably used, for example, in a reformer provided in a fuel cell system for moving bodies such as automobiles or small-scale power generation.

  The fuel cell system of the present invention can be easily made compact, and can be suitably applied to the fuel cell system as described above.

It is sectional drawing which shows an example of the burner of this invention. It is typical sectional drawing which shows the example of the reformer with which the burner of this invention was mounted | worn. It is a block diagram which shows the outline of the fuel cell system which has a reformer equipped with the burner of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Burner casing 1a Joint part 2 Vaporizer 4 Extension cylinder 5 Rectifier 6 Burner mat 8 Igniter 9 Electric heater 10 First gas flow path 11 Air inlet 12 Liquid fuel nozzle 13 Heating surface 14 Heating surface and vaporizer side wall Air gap 20 Second gas flow path 21 Hydrogen electrode off-gas inlet 101 Burner 102 Reformer 103 Fuel cell 103a Hydrogen electrode 103c Air electrode 111 Processing unit 121 Flow meter (for liquid fuel)
122 Flow controller (for liquid fuel)
123 Flow control valve (for liquid fuel)
131 Flow meter (for air)
132 Flow controller (for air)
133 Flow control valve (for air)

Claims (6)

In a reformer burner for supplying heat for reforming reaction to a reformer used in a fuel cell system to reform a raw material for hydrogen production to obtain a reformed gas containing hydrogen,
Have only two gas flow paths that do not communicate with each other,
The gas inlet of the first gas channel is an oxygen-containing gas inlet for introducing the oxygen-containing gas, the gas outlet of the first gas channel is provided with a burner mat, and the first gas channel is the first gas channel A liquid fuel nozzle for flowing the liquid fuel into the gas flow path, and a heating surface for vaporizing the flowed liquid fuel,
The gas inlet of the second gas channel is a hydrogen electrode off-gas inlet for introducing the hydrogen electrode off-gas of the fuel cell, and the hydrogen electrode off-gas is supplied downstream of the burner mat to the gas outlet of the second gas channel. A reformer burner comprising a hydrogen electrode off-gas nozzle.   The reformer burner according to claim 1, wherein the burner mat is made of a woven or non-woven fabric of metal fibers.   The reformer burner according to claim 1 or 2, further comprising control means for controlling the combustion air ratio based on liquid fuel to 1.5 or less. The burner according to any one of claims 1 to 3, wherein a combustion amount of the liquid fuel per unit area of the burner mat is 200 kW / m ² or more and 4500 kW / m ² or less.   The burner according to any one of claims 1 to 4, wherein a combustion amount based on a liquid fuel is 8.1 kW or less. In a fuel cell system comprising a reformer that reforms a raw material for hydrogen production to obtain a reformed gas containing hydrogen, and a fuel cell that uses the reformed gas as fuel,
The reformer comprises a reformer burner for supplying heat for the reforming reaction;
The reformer burner has only two gas flow paths that do not communicate with each other,
The gas inlet of the first gas channel is an oxygen-containing gas inlet for introducing an oxygen-containing gas, the gas outlet of the first gas channel is provided with a burner mat, and the first gas channel is the first gas channel A liquid fuel nozzle for flowing the liquid fuel into the gas flow path, and a heating surface for vaporizing the flowed liquid fuel,
The gas inlet of the second gas channel is a hydrogen electrode off-gas inlet for introducing the hydrogen electrode off-gas of the fuel cell, and the hydrogen electrode off-gas is supplied downstream of the burner mat to the gas outlet of the second gas channel. A fuel cell system comprising a hydrogen electrode off-gas nozzle.

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