JP4074617B2 - Catalyst combustor, combustion heater, and fuel cell system - Google Patents

Description

  The present invention relates to a catalytic combustor that generates heat by a catalytic reaction, a combustion heater that heats a cooling medium using the heat generated by the catalytic combustor, and a fuel cell system equipped with the catalytic combustor.

  Conventionally, various types of catalytic combustors have been proposed. For example, the catalytic combustor described in Patent Document 1 is mounted on a fuel cell system, and when the system is started, a mixed gas composed of methanol as fuel gas and air as oxidant gas is heated by a heater. It is sent to the catalyst combustion section later, and during normal operation, the air supplied without heating by the heater and the exhaust reformed gas and exhaust air discharged from the downstream side of the heater are mixed and sent to the catalyst combustion section. It is configured.

By the way, in this type of catalytic combustor, it is difficult to mix the fuel gas and oxidant gas in the catalytic reaction at a uniform concentration. As a result, the combustion temperature in the catalytic combustion section is uneven and the system performance is lowered. There is a problem to do. Therefore, as a means for obtaining a mixed gas having a uniform concentration of the fuel gas and the oxidant gas, the fuel gas and the oxidant gas are mixed so that the fuel is opposed to the inlet-side surface of the catalyst combustion part. A catalytic combustor in which a plurality of tubular fuel supply ports for gas supply are arranged in parallel and a plurality of fuel injection holes are provided in each fuel supply port has been proposed (for example, see Patent Document 2).
JP 2001-21112 (paragraphs 0013 to 0020, FIG. 1) JP 2003-21945 (paragraphs 0060-0069, FIG. 6)

  However, in the conventional catalytic combustor described in Patent Document 2, the supply amount of the fuel gas supplied to the catalyst combustion unit is likely to vary with respect to the surface direction, and the mixing ratio of the fuel gas and the oxidant gas is uneven. Therefore, when the ratio of the fuel gas is large, the calorific value increases and the temperature of the catalyst becomes high, and the catalyst may be locally degraded. Further, in the catalytic combustor of Patent Document 2, since the fuel gas is supplied immediately before the catalytic combustion portion, it is difficult for the fuel gas and the oxidant gas to be mixed evenly.

  Further, as shown in Patent Document 1, in the case where a heat exchanger that transmits the heat of combustion gas to the refrigerant is provided on the downstream side of the catalyst combustion unit, the fuel gas and the oxidant gas supplied to the catalyst combustion unit If the mixing ratio varies in the surface direction, the amount of heat generated by the combustion gas supplied to the heat exchanger varies, resulting in a decrease in heat conversion efficiency or a locally high temperature of the cooling medium passing through the heat exchanger. Thus, the cooling medium may be deteriorated.

The present invention solves the above-mentioned conventional problems, and makes the mixing ratio of the fuel gas and the oxidant gas supplied to the catalytic combustion section uniform so that the temperature distribution in the catalytic combustion section is uniform. It is an object of the present invention to provide a catalytic combustor that can be made to operate.
The present invention also includes a heat exchanger that heats the cooling medium using the combustion gas generated by the catalytic combustor as a heat source, and is intended to improve the combustion heater excellent in heat conversion efficiency and system performance. An object of the present invention is to provide a fuel cell system that can be used.

The catalytic combustor of the present invention is a catalytic combustor having a catalytic combustion section for burning a mixed gas of a fuel gas and an oxidant gas supplied from a mixer, and is provided upstream of the catalytic combustion section. A rectifying plate that gives at least a pressure loss to the mixed gas, and the rectifying plate has a three-dimensional network structure in which an opening diameter through which the mixed gas passes is set to be equal to or smaller than a flame extinguishing diameter of the mixed gas. The reinforcing plate having a plurality of through holes is laminated on both surfaces of the rectifying plate, and the pores inside the porous body communicate with each other from the surface of one reinforcing plate to the other reinforcing plate. It is characterized by a pore structure .

  According to the present invention, the mixing ratio of the fuel gas and the oxidant gas in the mixed gas flowing into the catalytic combustion section can be made uniform by providing a flow rectifying plate and generating a pressure loss in the mixed gas. It can prevent that the combustion temperature in a combustion part becomes non-uniform | heterogenous.

  Thus, the opening diameter of the opening formed in the current plate is set to be equal to or smaller than the flame extinguishing diameter of the mixed gas, so that the current plate can also be used as a flame extinguishing plate. Therefore, when a flame is generated in the catalytic combustion section, a function to prevent the flame from propagating to the upstream fuel gas supply side, that is, a so-called backfire prevention function can be exhibited. In addition, since it is not necessary to provide a separate flame extinguishing plate, the catalytic combustor can be reduced in size and weight.

  For example, the current plate is made of a foam metal. By selecting the foam metal as the rectifying plate, the fuel gas and the oxidant gas are mixed in the direction in which the pressure loss becomes uniform, and the fuel gas and the oxidant gas are further stirred in the foam metal, The mixing ratio of the fuel gas and the oxidant gas can be made uniform with high accuracy.

  The combustion heater of the present invention includes the catalytic combustor, and a heat exchanger that is provided on the downstream side of the catalytic combustor and heats a cooling medium using combustion gas generated by the catalytic combustor as a heat source. It is characterized by that.

  According to the combustion heater of the present invention, uneven combustion in the catalytic combustor can be prevented, so that the cooling medium can be heated with a heat source in a uniform temperature range, and heat conversion efficiency can be increased.

  The fuel cell system of the present invention includes a fuel cell that generates power by a chemical reaction between a fuel gas and an oxidant gas, a cooling unit that circulates a cooling medium in the fuel cell to cool the fuel cell, and the catalyst. A combustor, a mixer for mixing the fuel gas and the oxidant gas and supplying the mixture to the catalytic combustor, and a heat exchanger for heating the cooling medium using the combustion gas generated by the catalytic combustor as a heat source It is characterized by providing.

  According to the fuel cell system of the present invention, since the temperature distribution of the combustion gas supplied from the catalytic combustor can be made uniform, the pressure inside the cooling means can be stabilized.

  According to the catalytic combustor of the present invention, uneven combustion can be prevented, and deterioration of the catalyst due to local high temperatures can be prevented. Moreover, according to the combustion heater of this invention, while being able to improve heat conversion efficiency, the quality change of a cooling medium can be prevented. Moreover, according to the fuel cell system of the present invention, the system performance can be improved.

(First embodiment)
Hereinafter, a combustion heater equipped with the catalytic combustor of the first embodiment will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing a combustion heater, FIG. 2 shows a rectifying plate of the catalytic combustor of the first embodiment, (a) is a plan view, (b) is a cross-sectional view along line BB in FIG. 3 is a diagram schematically showing the flow of the mixed gas introduced into the catalytic combustor of the first embodiment, and FIG. 4 is a cross-sectional view taken along line AA of FIG.

  As shown in FIG. 1, the combustion heater 10 includes a catalytic combustor 11 </ b> A and a heat exchanger 1. A mixer 52 is connected to the upstream side of the combustion heater 10 via a pipe 15. The mixer 52 is provided in a fuel cell system F1 (see FIG. 5), which will be described later, and supplies a mixed gas Mg composed of hydrogen as fuel gas and air as oxidant gas to the catalytic combustor 11A. It is configured.

  The catalytic combustor 11A includes a metal case 12 formed in a cylindrical shape, a catalyst combustion part 13 accommodated in the case 12, and a support member 14 that supports the catalyst combustion part 13 in the case 12. And the current plate 9A.

  The catalytic combustion section 13 is formed by supporting an oxidation catalyst such as platinum or palladium on a cylindrical base material having a large number of fine gas flow passages.

  The current plate 9A is formed in a disc shape as shown in FIG. 2A, and is disposed in the case 12 on the upstream side of the catalytic combustion unit 13 as shown in FIG. As shown in FIG. 2B, the rectifying plate 9 </ b> A is made of a foam metal plate 9, and reinforcing plates 19 are provided so as to sandwich both surfaces of the foam metal plate 9.

  Although not shown, the foam metal plate 9 is a metal porous body having a three-dimensional network structure similar to that of a resin foam such as sponge, and the internal pores are formed from one reinforcing plate 19 side surface. It has a continuous pore structure communicating with the surface of the other reinforcing plate 19. The foam metal plate 9 is formed of a metal such as stainless steel, aluminum, copper, or nickel, but is not limited to a metal and may be a non-metal such as ceramic. The opening diameter of the pores formed in the metal foam plate 9 is preferably set to be equal to or less than the flame extinguishing diameter of the mixed gas (hydrogen and air in the case of the fuel cell system F1 shown in FIG. 3) Mg. The extinguishing diameter is the maximum dimension through which no flame can pass.

  Thus, by setting the opening diameter of the metal foam plate 9 to be equal to or smaller than the extinguishing diameter, it is possible to prevent the flame from being transmitted to the mixer 52 through the rectifying plate 9A. For example, the flame extinguishing diameter is preferably set to about 0.6 mm or less when the mixed gas (fuel gas / oxidant gas) Mg is hydrogen / air, and the mixed gas (fuel gas / oxidant gas) Mg If propane gas / air, it is preferable to set it to about 2.7 mm or less. However, the illustrated flame extinguishing diameter is not determined only by the type of the mixed gas, but varies depending on the concentration and pressure of the fuel gas and the oxidant gas. It is preferable to set. Moreover, the pressure loss given to the mixed gas can be changed by changing the opening diameter of the metal foam plate 9.

  The reinforcing plate 19 is made of a metal material such as stainless steel or aluminum, and has a plurality of through holes 19a formed on one surface thereof. In addition, you may make it change the diameter of each through-hole 19a suitably according to the loss amount of the pressure given to mixed gas Mg. Further, the reinforcing plate 19 may not be provided as long as a sufficient strength can be ensured only by the current plate 9A formed of foam metal.

  As shown in FIGS. 1 and 4, the heat exchanger 1 includes a housing 2 and a heat exchanging unit 5 that is housed in the housing 2. The housing 2 is formed in a cylindrical shape from a metal material or the like. The heat exchanging unit 5 includes a heat supply tube group 3 and a heat recovery tube unit 4 each formed of a metal material or the like, and the heat supply tube group 3 is provided inside the heat recovery tube unit 4.

  As shown in FIG. 4, the heat supply pipe group 3 includes a plurality of (seven in this embodiment) heat supply pipes 3 a, 3 b, 3 b, each having a channel cross-section elongated in the vertical direction of the paper with a predetermined width dimension. 3c, 3c, 3d, and 3d, and the heat supply pipes 3a to 3d are arranged in parallel with a space therebetween. As for these heat supply pipes 3a-3d, the both ends of the longitudinal direction (paper surface up-down direction) all extend to the vicinity of the inner wall 4a of the heat recovery pipe part 4.

  The heat recovery pipe portion 4 has a substantially cylindrical shape, and the heat supply pipes 3a to 3d are supported by support members (not shown) in the above-described state in the inner space.

  In the heat exchanger 1, the heat recovery pipe portion 4 is provided inside the housing 2. At this time, the heat recovery is performed so that the air layer 6 is provided between the housing 2 and the heat recovery pipe portion 4. The tube portion 4 is supported by support members 4b and 4b (see FIG. 1). The space between the housing 2 and the heat recovery pipe portion 4 is not limited to the air layer 6. For example, an inorganic fiber-based heat insulating material such as glass wool, polystyrene foam, expanded polystyrene, rigid urethane foam, high foam You may fill with foamed plastic type heat insulating materials, such as polyethylene and a phenol resin foam. Moreover, it may be configured only by the heat supply tube group 3 and the heat recovery tube portion 4 without providing the housing 2.

  As shown in FIG. 1, the heat recovery pipe section 4 is provided with an introduction port 7 to which a cooling medium Mr is supplied at a lower portion located on the downstream side (right side in the figure) of the heat supply pipe group 3, A discharge port 8 through which the cooling medium Mr is discharged is provided at an upper portion located on the upstream side (the left side in the drawing) of the heat supply pipe group 3.

Next, the operation of the combustion heater 10 provided with the catalytic combustor 11A of the first embodiment will be described.
As shown in FIG. 1, the fuel gas and the oxidant gas are mixed in the mixer 52, and the mixed gas Mg is sent to the catalytic combustor 11 </ b> A through the pipe 15. At this time, when the mixed gas Mg hits the rectifying plate 9A provided on the upstream side of the catalyst combustion unit 13, the mixed gas Mg is temporarily retained and pressure loss occurs (see FIG. 3). As described above, once the flow (flow velocity or flow rate) of the mixed gas Mg is once suppressed, the fuel gas and the oxidant gas in the mixed gas Mg are evenly mixed. Moreover, since the mixed gas Mg is agitated in the foam metal by using the rectifying plate 9A as the foam metal, the fuel gas and the oxidant gas can be mixed evenly. The mixed gas Mg in an evenly mixed state is a through hole 19a (see FIGS. 2A and 2B) of one reinforcing plate 19, the inside of the metal foam plate 9, and the through hole of the other reinforcing plate 19. It is discharged toward the catalytic combustion section 13 through 19a. Thereby, it becomes possible to supply the mixed gas Mg with a uniform mixing degree of the fuel gas and the oxidant gas to the inlet side surface 13a (see FIG. 3) of the catalytic combustion unit 13, and the catalytic combustion unit The combustion temperature in 13 can be made uniform. Therefore, in the catalytic combustor 11 </ b> A, the combustion gas Ms having a uniform combustion temperature distribution can be supplied to the heat exchange unit 5.

  In the catalytic combustor 11A of the present embodiment, uneven combustion in the catalytic combustion unit 13 can be prevented, so that the combustion temperature in the catalytic combustion unit 13 becomes locally high, the catalyst deteriorates, It will be possible to prevent alteration.

  As shown in FIG. 4, the combustion gas Ms supplied to the heat exchanger 1 passes through the heat supply pipes 3 a to 3 d of the heat supply pipe group 3 and is discharged from the pipe 16. The cooling medium Mr supplied to the heat exchanger 1 is supplied from the introduction port 7 and is in a space (flow path) surrounded by the outside of each of the heat supply pipes 3a to 3d and the inside of the heat recovery pipe section 4. And is discharged from the discharge port 8 so as to flow in the opposite direction to the combustion gas Ms (see FIG. 1). In this way, the mixed gas Mg is combusted in the catalytic combustion unit 13 to generate the combustion gas Ms, and the cooling medium Mr is heated by using the combustion gas Ms as a heat source.

  In the combustion heater 10 of the present embodiment, the combustion gas Ms having a uniform temperature distribution can be obtained in the catalyst combustion unit 13, and therefore the cooling medium Mr passing through the heat exchange unit 5 is also heated so that the temperature distribution is uniform. The As described above, since the temperature distribution of the cooling medium Mr can be made uniform, the heat conversion efficiency can be increased. As a result, the temperature of the cooling medium Mr is locally increased, and the cooling medium Mr can be prevented from being altered or deteriorated.

  Next, the operation of the combustion heater 10 equipped with the catalytic combustor 11A of the present embodiment will be described by taking as an example the case where it is installed in a vehicle fuel cell system F1 (see FIG. 5). The combustion heater 10 is used when the fuel cell FC is warmed up by heating a coolant (cooling medium) Mr flowing in the cooling system 40 of the fuel cell FC, which will be described later.

First, the overall configuration of the fuel cell system F1 will be described with reference to FIG.
The fuel cell system F1 includes a fuel cell FC, a hydrogen supply system 20, an air supply system 30, a cooling system 40, a warm-up system 50, a dilution system 70, and a control device 80.

  The fuel cell FC is a PEM (Proton Exchange Membrane) type fuel cell having an anode electrode (hydrogen electrode) P1 and a cathode electrode (oxygen electrode) P2, and hydrogen as a fuel gas is supplied to the anode electrode P1, and the cathode Electric power is generated by supplying air as an oxidant gas to the pole P2.

  The hydrogen supply system 20 is provided with a high-pressure hydrogen tank 21, a shut-off valve 22, and a regulator (pressure reduction means) 23 on the upstream side of the anode P <b> 1. A check valve 24 and a fuel pump 25 are provided on the downstream side of the anode P1. Each device of the hydrogen supply system 20 is connected by fuel pipes 29a to 29f. Hydrogen from the high-pressure hydrogen tank 21 is supplied to the anode P <b> 1 through the shut-off valve 22 and the regulator 23. The anode off-gas discharged from the anode P1 flows into the fuel pump 25 through the check valve 24, is pumped to the fuel pump 25, and is introduced (recirculated) to the anode P1 again.

  In the air supply system 30, an air pump 31 is provided on the upstream side of the cathode electrode P2, and a back pressure valve 32 is provided on the downstream side of the cathode electrode P2. The air pump 31 is a supercharger or the like driven by a motor, and the rotational speed of the motor is controlled by a signal from the control device 80. Each device of the air supply system 30 is connected by air pipes 39a and 39b. The back pressure valve 32 is actuated by a signal from the control device 80. Note that the air supplied to the fuel cell FC is humidified by a humidifier (not shown).

  The cooling system 40 includes a radiator 41, a thermostat valve 42, a water pump 43, and a three-way electromagnetic valve 44. Each device of the cooling system 40 is connected by coolant pipes 49a to 49f, and a temperature sensor 45 that detects the outlet side coolant temperature of the fuel cell FC as the temperature of the fuel cell FC is installed in the coolant pipe 49a. . The thermostat valve 42 circulates the coolant without passing through the radiator 41 when the fuel cell FC is warmed up so as to promote warming up of the fuel cell FC. The three-way solenoid valve 44 is actuated by a signal from the control device 80, and a normal operation position for supplying the coolant from the water pump 43 directly to the fuel cell FC without passing through the combustion heater 10, and the combustion heater. 10 is switched to the warm-up operation position to be supplied to 10. The radiator 41, the thermostat valve 42, the water pump 43, the three-way solenoid valve 44, and the coolant pipes 49a to 49f constitute the cooling means of this embodiment.

  The warming-up system 50 includes the combustion heater 10 according to the present embodiment. The combustion heater 10 burns anode off gas and hydrogen (fuel gas), and plays a role of warming up the fuel cell FC with the thermal energy. In addition to the combustion heater 10, the warm-up system 50, as described above, mixes the anode off-gas or hydrogen (combustion gas) introduced into the combustion heater 10 and the cathode off-gas (oxidant gas). And. The warm-up system 50 includes a first fuel gas line 67 that guides the anode off gas to the mixer 52, a third fuel gas line 68 that guides hydrogen to the mixer 52, and a first cathode that guides the cathode off gas to the mixer 52. An off-gas line 64 and a warm-up system coolant line 69 that guides the coolant of the fuel cell FC to the combustion heater 10 are provided.

  The first fuel gas line 67 includes fuel pipes 67a to 67c communicating with the fuel pipe 29d on the downstream side of the anode P1 and the mixer 52, a steam / water separator 53 connected by the fuel pipes 67a to 67c, The first gas flow control valve 54 is configured. The first gas flow rate control valve 54 is actuated by a signal from the control device 80. The steam / water separator 53 separates the moisture in the anode offgas flowing from the fuel pipe 67a by a plate (not shown), and flows the anode offgas from which the moisture has been removed into the fuel pipe 67b on the mixer 52 side, so that the dilution apparatus 71 side An anode off gas containing moisture is caused to flow into a fuel pipe 79a described later. A flow rate sensor 55 that detects the amount of fuel gas supplied to the mixer 52 is installed in the fuel pipe 67c.

  The third fuel gas line 68 is interposed between the fuel pipes 68a and 68b that connect the fuel pipe 29c of the hydrogen supply system 20 and the fuel pipe 67c of the first fuel gas line 67, and the fuel pipes 68a and 68b. And a third gas flow rate control valve 56. The third gas flow rate control valve 56 is controlled by a signal from the control device 80.

  The first cathode off-gas line 64 has air pipes 64a and 64b connecting the outlet side of the back pressure valve 32 in the air supply system 30 and the mixer 52, and a steam / water separation interposed between the air pipes 64a and 64b. And a device 57. The steam / water separator 57 is of the same plate type as the steam / water separator 53 and separates moisture in the cathode off-gas flowing in from the air pipe 64a on the cathode P2 side by a plate, and the air pipe on the mixer 52 side. The cathode off gas from which moisture has been removed is caused to flow into 64b, and the cathode off gas containing moisture is caused to flow into an air pipe 78a described later on the dilution device 71 side.

  The warm-up system coolant line 69 supplies the coolant supplied from the three-way solenoid valve 44 to the combustion heater 10 and supplies the coolant heated by the combustion heater 10 to the fuel cell FC. And a coolant pipe 69b.

  The dilution system 70 includes a dilution device 71 connected to the combustion heater 10, and plays a role of diluting the anode off-gas and the exhaust gas of the combustion heater 10 with the oxygen-containing gas in the dilution device 71 and releasing it into the atmosphere. Is responsible. The diluting device 71 has a storage chamber 71b and a diffusion chamber 71c partitioned by a perforated plate 71a. The anode off gas flowing into the storage chamber 71b gradually flows into the diffusion chamber 71c through the perforated plate 71a, and is diluted by mixing with the oxygen-containing gas in the diffusion chamber 71c, and then discharged into the atmosphere. The dilution system 70 also has a second fuel gas line 79 that guides the anode off gas to the diluting device 71 and a second cathode off gas line 78 that guides the cathode off gas to the diluting device 71.

  The second fuel gas line 79 includes fuel pipes 79a and 79b that connect the steam / water separator 53 and the storage chamber 71b of the dilution device 71, and a second gas flow rate control interposed between the fuel pipes 79a and 79b. And a valve 72. The second gas flow rate control valve 72 is actuated by a signal from the control device 80.

  The second cathode off-gas line 78 includes air pipes 78a and 78b that connect the steam / water separator 57 and the diluting device 71, and an orifice 73 interposed between the air pipes 78a and 78b.

Next, warm-up control of a vehicle equipped with the fuel cell system F1 will be described.
When an ignition switch (not shown) of the vehicle is turned on by the driver, the control device 80 starts warm-up control. The control device 80 switches the three-way solenoid valve 44 to a warm-up operation position where the cooling medium Mr from the water pump 43 is supplied to the combustion heater 10. Then, the third gas flow control valve 56 is driven by a predetermined amount in the valve opening direction, the first gas flow control valve 54 and the second gas flow control valve 72 are closed, and the third fuel gas is supplied to the mixer 52. Hydrogen (fuel gas) in the high-pressure hydrogen tank 21 is introduced through the line 68 and the fuel pipe 67c. The amount of hydrogen introduced at this time is monitored by the flow sensor 55. On the other hand, the cathode off-gas (oxidant gas) discharged from the cathode electrode P 2 is almost entirely introduced into the mixer 52 via the first cathode off-gas line 64.

  Hydrogen and cathode off gas (oxygen) are mixed in the mixer 52 and then introduced into the catalytic combustion section 13 of the combustion heater 10. Then, in the catalytic combustion unit 13, hydrogen and oxygen in the cathode off gas undergo catalytic combustion, and combustion gas Ms (see FIG. 1) as a heat source is generated. The generated combustion gas Ms is sent to the heat exchanger 1, and in this heat exchanger 1, the heat of the combustion gas Ms is given to the cooling medium Mr via the heat supply pipes 3a to 3d, and the cooling medium Mr is Heated. The heated cooling medium Mr is supplied to the fuel cell FC through the coolant pipe 69b and the coolant pipe 49e. At this time, the temperature of the fuel cell FC is monitored by the temperature sensor 45, and hydrogen and cathode offgas (oxygen) are supplied to the combustion heater 10 until the temperature at which the fuel cell FC can generate power is reached to continue warming up. . After the warm-up is completed, the three-way solenoid valve 44 is driven to the normal operation position so that the cooling medium Mr from the water pump 43 is directly supplied to the fuel cell FC without passing through the combustion heater 10.

  Thus, the heat conversion efficiency in the heat exchanger 1 can be increased by mounting the combustion heater 10 of the present embodiment on the fuel cell system F1. As a result, fuel consumption during warm-up can be reduced. Further, by increasing the heat conversion efficiency, the heat exchanger 1 can be reduced in size and weight, and the combustion heater 10 can be reduced in size and weight.

  The warm-up control described above is an example, and can be changed as appropriate based on the temperature of the fuel cell FC during warm-up. For example, hydrogen is not supplied directly from the high-pressure hydrogen tank 21 to the mixer 52, but remains in the anode P1 and the fuel pipes 29c to 29f when the fuel cell system F1 is started (when the ignition switch is turned on). The fuel cell system F <b> 1 may be warmed up using the anode off-gas discharged from the fuel cell FC as a fuel gas, using a process (purge process) for discharging water and impurities.

  When warming up using the anode off-gas in the purge process in this way, the three-way solenoid valve 44 is driven to the warm-up operation position under the control of the control device 80. Then, the third gas flow rate control valve 56 is closed, the first gas flow rate control valve 54 is opened, the second gas flow rate control valve 72 is closed, and the total amount of the anode off gas purged from the anode P1 is supplied to the mixer 52. Then, approximately the entire amount of the cathode off-gas discharged from the cathode electrode P2 flows in, and the anode off-gas and the cathode off-gas are catalytically combusted in the combustion heater 10 to generate combustion gas Ms (thermal energy). As described above, the anode off gas that has been conventionally discharged can be used for warming up the fuel cell FC, so that the amount of fuel consumption can be reduced.

  The moisture contained in the anode off-gas is separated in the steam / water separator 53, and the moisture contained in the cathode off-gas is separated in the steam / water separator 57. Therefore, the combustion heater 10 does not contain moisture. Off-gas and cathode off-gas are supplied, thereby enabling stable combustion.

  Thus, by mounting the combustion heater 10 of the present embodiment on the fuel cell system F1, the system performance can be improved by increasing the heat conversion efficiency in the heat exchanger 1.

  In the fuel cell system F1 of the present embodiment, since the mixer 52 is provided in the vicinity of the upstream side of the catalytic combustor 11A, the fuel gas and the oxidant gas mixed in the mixer 52 are further mixed. Thus, the mixing ratio of the fuel gas and the oxidant gas can be further increased, and the combustion temperature distribution in the catalytic combustion unit 13 can be made uniform with high accuracy.

(Second Embodiment)
FIG. 6 shows a current plate provided in the catalytic combustor of the second embodiment, (a) is a plan view, (b) is a sectional view taken along the line CC of (a), and FIG. 7 is a catalyst of the second embodiment. It is a figure which shows typically the flow of the mixed gas introduce | transduced into a combustor.
As shown in FIG. 6 (a), the rectifying plate 9B of the catalytic combustor 11B of the second embodiment is composed of a plurality of flat plates 19b and a plurality of corrugated plates 19c. The wave fronts of the plates 19c are joined to each other by brazing or the like. A plurality of structural plates in which the flat plate 19b and the corrugated plate 19c are joined are stacked so as to be concentric. Further, the pitch of the corrugations of the corrugated plate 19c is formed constant, and the size of the gap 19d having a substantially triangular cross section surrounded by the flat plate 19b and the corrugated plate 19c is set constant.

  Note that the structure of the rectifying plate 9B is not limited to a concentrically stacked one, and a structure in which one flat plate 19b and a corrugated plate 19c each formed in a long shape are stacked from the center to the outer periphery. It may be configured to be spirally wound toward the side. Alternatively, a plurality of flat plates 19b and corrugated plates 19c may be stacked so as to extend linearly. Further, the corrugated plate 19c may have an angular uneven shape.

  In the second embodiment, even when the rectifying plate 9B is provided, as shown in FIG. 7, the mixed gas Mg of the fuel gas and the oxidant gas from the mixer 52 (see FIG. 5) is the catalyst. When supplied to the combustor 11B, the mixed gas Mg hits the rectifying plate 9B, and pressure loss is given to the mixed gas Mg. As a result, the mixed gas Mg once stays in front of the rectifying plate 9B, so that the mixing ratio of the fuel gas and the oxidant gas of the mixed gas Mg is further uniformed, and the uniform mixed gas Mg is rectified. The catalyst 9 is supplied to the catalytic combustion unit 13 through the gaps 19d of 9B. In the second embodiment, unlike the first embodiment, the mixing ratio is not increased in the direction of equalizing inside the rectifying plate 9B, but a pressure loss occurs in the mixed gas Mg before the rectifying plate 9B. Therefore, the combustion temperature in the catalyst combustion part 13 can be made uniform. As a result, it is possible to prevent local high temperature in the catalytic combustion unit 13, and therefore, deterioration of the catalyst in the catalytic combustion unit 13 can be prevented. Even when this catalytic combustor 11B is mounted on the combustion heater 10, it is possible to prevent the cooling medium Mr from being deteriorated due to local high temperatures. Furthermore, by setting the opening diameter of each gap 19d formed in the rectifying plate 9B to be equal to or smaller than the extinguishing diameter, it is possible to prevent the flame from passing through the rectifying plate 9B, and it is not necessary to provide the extinguishing plate separately.

  The catalytic combustors 11A and 11B, the combustion heater 10, and the fuel cell system F1 according to the present invention are not limited to vehicles, and can be applied as various other combustion heaters such as for ships and for hot water supply.

It is sectional drawing which shows a combustion heater. The baffle plate of the catalytic combustor of 1st Embodiment is shown, (a) is a top view, (b) is the BB sectional drawing of (a). It is a figure which shows typically the flow of the mixed gas introduce | transduced into the catalytic combustor of 1st Embodiment. It is the sectional view on the AA line of FIG. It is a block diagram when the combustion heater of this embodiment is mounted in the fuel cell system for vehicles. The baffle plate of the catalyst combustor of 2nd Embodiment is shown, (a) is a top view, (b) is CC sectional view taken on the line of (a). It is a figure which shows typically the flow of the mixed gas introduced into the catalytic combustor of 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heat exchanger 9 Foamed metal plate 9A, 9B Rectification plate 10 Combustion heater 11A, 11B Catalytic combustor 13 Catalytic combustion part 19 Reinforcement plate 19a Through-hole 19b Flat plate 19c Corrugated plate 52 Mixer Mg Mixed gas Mr Cooling medium Ms Combustion gas

Claims (3)

A catalytic combustor comprising a catalytic combustion section for combusting a mixed gas of a fuel gas and an oxidant gas supplied from a mixer,
Provided upstream of the catalytic combustion portion has a rectifying plate to provide at least pressure loss in the mixed gas,
The rectifying plate is a porous body having a three-dimensional network structure in which an opening diameter through which the mixed gas passes is set to be equal to or smaller than a flame extinguishing diameter of the mixed gas,
A reinforcing plate having a plurality of through holes is laminated on both surfaces of the rectifying plate, and the pores inside the porous body have a continuous pore structure that communicates from the surface of one reinforcing plate to the other reinforcing plate. catalytic combustor, characterized in that there. A catalyst combustor according to claim 1, and a heat exchanger that is provided on the downstream side of the catalyst combustor and heats a cooling medium by using combustion gas generated by the catalyst combustor as a heat source. A combustion heater. 2. A fuel cell that generates electric power by a chemical reaction between a fuel gas and an oxidant gas; cooling means for circulating a cooling medium in the fuel cell to cool the fuel cell; and the catalytic combustor according to claim 1, A mixer that mixes fuel gas and the oxidant gas and supplies the mixed gas to the catalytic combustor; and a heat exchanger that heats the cooling medium using the combustion gas generated by the catalytic combustor as a heat source. A fuel cell system.

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