JP2000323161A - Fuel cell fuel reformer - Google Patents

Abstract

(57) [Problem] To provide a fuel reformer for a fuel cell capable of immediately changing the generation amount of reformed gas in response to a load change. SOLUTION: A sub-evaporator 6 for storing a mixture of water and fuel in a heated and pressurized state, and an evaporator using the heated and pressurized mixture as an auxiliary fuel vapor in response to a request for increasing the amount of reformed gas generated. The fuel reformer 1 is provided with a control means for supplying the fuel to the fuel reformer 3. When the heated and pressurized liquid mixture is supplied to the evaporator 3, the pressure of the liquid mixture drops rapidly, so that the liquid mixture is evaporated under reduced pressure to generate new fuel gas, that is, auxiliary fuel vapor. According to such a fuel reforming apparatus 1, when an increase in the reformed gas generation amount is requested, the fuel gas amount can be made larger than before the request for the increase in the reformed gas. It becomes possible to increase.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel reformer for a fuel cell for producing a reformed gas from a fuel gas, and more particularly to a reformed gas immediately supplied to a reformed gas in response to a demand for increasing the reformed gas. The present invention relates to a fuel reformer for a fuel cell which can be increased.

[0002]

2. Description of the Related Art A polymer electrolyte fuel cell comprises a stack cell in which a polymer electrolyte membrane is sandwiched between an anode and a cathode. Hydrogen is supplied to the anode and oxygen is supplied to the cathode. A reaction is generated to generate electricity. Conventionally, a fuel reformer has been used as a hydrogen supply source of the fuel cell. This fuel reformer generates a fuel gas by vaporizing a hydrocarbon or alcohol fuel and water, and reforms it using a reforming catalyst to produce a reformed gas containing hydrogen. It is. The fuel cell and the fuel reformer constitute a fuel cell system.

[0003] This conventional fuel cell system will be described with reference to the drawings. FIG. 7 shows a conventional fuel cell system 101.
FIG. The fuel cell system 101 includes a fuel cell 102, a fuel reformer 103, and a secondary battery 111
It is composed of The fuel cell 102 is of a solid polymer type, and is configured by stacking a plurality of stack cells each having a polymer electrolyte membrane sandwiched between an anode and a cathode. The fuel reformer 103 supplies a reformed gas containing hydrogen to the fuel cell 102. Secondary battery 111
Is a device that charges the electric power generated by the fuel cell 102, and includes, for example, a lead battery, a nickel-metal hydride battery, and a lithium ion battery. The fuel cell system 101 (secondary battery 111) includes a load device 1
12 are connected.

The fuel reformer 103 includes a combustor 104 for generating a combustion gas, and an evaporator 105 for evaporating a mixture of fuel and water by the heat of the combustion gas to generate a fuel gas.
And a reformer 106 that includes a reforming catalyst (not shown) and reforms fuel gas with the reforming catalyst to generate a reformed gas containing hydrogen. Evaporator 10
5 is a mixed liquid tank 1 filled with a mixed liquid of water and fuel.
07 is provided so that water and fuel can be supplied to the evaporator 105. As the fuel, for example, methanol is used. Exhaust gas containing unreacted gas is supplied from the fuel cell 102 to the combustor 104,
Combustion gas can be generated by burning this exhaust gas.

In this fuel cell system 101,
The reformed gas is generated in the fuel reformer 103, and the reformed gas is supplied to the anode of the fuel cell 102 to generate power. The generated power is temporarily charged in the secondary battery 111, and the load device 112 Of the secondary battery 11
1 to the load device 112.

In the above-described fuel cell system 101, the secondary battery 111 is charged with a certain amount of power, and power corresponding to the load of the load device 112 is supplied from the secondary battery 111 to the load device 112. Because it is composed, 2
The secondary battery 111 plays a role as a power buffer, and can supply power stably even when the load amount increases rapidly.

By the way, the above-mentioned fuel cell system 101
Since the secondary battery 111 plays a role as a buffer, it is necessary to secure a large charging capacity, so that the size and weight of the secondary battery 111 become large.
There is a problem that 01 itself becomes large.

In order to solve this problem, a secondary battery 1
A fuel cell system that does not require the use of the fuel cell 11 or has a small and small-capacity secondary battery is required. For this purpose, it is necessary to cause the power generation amount of the fuel cell 102 to immediately follow a load change, To achieve this, the fuel cell 1
In view of the fact that the power generation amount of 02 is mainly controlled by the supply amount of the reformed gas, it is necessary to immediately change the generation amount of the reformed gas in the fuel reformer 103 according to the load change.

[0009]

In the fuel reformer 103 for a fuel cell, the amount of reformed gas generated depends on the amount of fuel gas generated. In order to change the amount, it is necessary to change the amount of fuel gas generated in accordance with the change in the load amount. However, during normal operation, the evaporator 105 of the conventional fuel reformer 103 uses combustion gas generated by burning the exhaust gas of the fuel cell 102 as a heat source, and the amount of combustion gas generated is substantially equal to the amount of raw fuel generated. There is a problem that it is difficult to fluctuate the amount of fuel gas generated in accordance with the fluctuation of the load amount because it is constant so as to be in equilibrium.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a fuel reformer for a fuel cell capable of immediately changing the amount of reformed gas generated in response to a load change. The purpose is to provide.

[0011]

In order to achieve the above object, the present invention employs the following constitution. The fuel reformer for a fuel cell of the present invention evaporates water and fuel to generate a fuel gas (evaporator 3 in the embodiment), and reforms the fuel gas to generate a reformed gas. A sub-evaporator (in the embodiment, the sub-evaporators 6 and 56) for storing a mixed liquid of water and fuel in a heated and pressurized state; Control means for supplying the auxiliary fuel vapor generated by evaporating the mixed solution in the heated and pressurized state under reduced pressure in response to a request for increasing the amount of reformed gas generated, to the evaporator.

When the heated and pressurized liquid mixture is supplied to the evaporator through the control valve, the pressure of the liquid mixture drops rapidly, so that the liquid mixture is evaporated under reduced pressure to generate auxiliary fuel vapor. Steam is supplied to the evaporator. Therefore, according to such a fuel reforming apparatus, auxiliary fuel vapor (fuel gas) is additionally supplied from the sub-evaporator in response to a request for increasing the amount of reformed gas generated. Therefore, the amount of the fuel gas is larger than that of the fuel gas, thereby making it possible to increase the amounts of the reformed gas and the combustion gas generated.

The sub-evaporator may include one or more sub-evaporators (in the embodiment, sub-evaporators 7, 7A, 7B, 7B).
C), and the sub-evaporation section is provided with a heating passage (a heating passage 3 in the embodiment) through which a heating medium passes.
1), a heat storage chamber filled with the heat storage material and provided adjacent to the heating passage (heat storage chamber 32 in the embodiment), and provided adjacent to the heat storage chamber while storing the mixed liquid. A liquid mixture chamber (a liquid mixture chamber 33 in the embodiment), and the control means includes at least one or more control valves (a control valve 25 in the embodiment) provided on the outlet side of each of the liquid mixture chambers. , 71, 72, 73), and when a signal for requesting an increase in the amount of reformed gas generated is input, the control valve is partially or entirely opened based on the required value of the signal, whereby Adjustment unit for adjusting the supply amount of the auxiliary fuel vapor to the evaporator (adjustment units 22, 62 in the embodiment)
Is preferably provided.

In such a sub-evaporator, when the heating medium passes through the heating passage, heat is exchanged between the heating medium and the heat storage material to heat the heat storage material. Further, heat exchange is performed between the heat storage material and the mixed liquid to heat the mixed liquid, and the mixed liquid is stored in a heated and pressurized state. In this manner, the heat exchange between the heating medium and the mixed liquid via the heat storage material allows the mixed liquid to be efficiently heated by the heat of the heating medium. Further, according to the control means, when the auxiliary fuel vapor is supplied to the evaporator by newly opening part or all of the control valve in accordance with the required amount of reformed gas generated, The amount of the supplementary fuel vapor to be added can be adjusted by the number of control valves to be operated, thereby making it possible to generate an amount of fuel gas corresponding to the required amount of reformed gas.

In the fuel reformer for a fuel cell according to the present invention, the evaporator is provided with a combustor (in the embodiment, a combustor 2) for generating a heating medium, and the heating medium passes through the evaporator. It is configured to be introduced into the sub-evaporator. Thus, the heating medium generated in the combustor can be reused in the sub-evaporator, and the thermal efficiency of the fuel reformer can be improved.

The evaporator is configured to heat the auxiliary fuel vapor supplied from the sub-evaporator. As a result, the mixed solution supplied from the sub-evaporator is heated by the evaporator at the same time as being evaporated under reduced pressure,
High-temperature fuel gas can be used.

Further, the control means includes a temperature detector (a thermometer 27 in the embodiment) for detecting a temperature of the heat storage material,
When the temperature of the heat storage material reaches the heat storage upper limit temperature, a temperature control unit (the temperature control unit 23 in the embodiment) that opens a part or all of the control valve may be provided. According to this control means, when the temperature of the heat storage material reaches the heat storage upper limit temperature, the mixed liquid is supplied to the evaporator and a new mixed liquid is supplied to the sub-evaporator at the same time. Since the temperature of the heat storage material is lower than the temperature of the heat storage material, the heat storage material is cooled, so that an excessive rise in temperature of the heat storage material can be prevented. At this time, the amount of water and fuel supplied to the evaporator is
By reducing the amount of the auxiliary fuel vapor supplied from the sub-evaporator to a reduced amount, fuel is saved and the efficiency of the fuel reformer does not decrease.

Further, a mixed liquid introducing passage (in the embodiment, mixed liquid introducing pipes 33F, 56B, 56) is provided at the inlet side of the sub-evaporator.
C, 56D and an introduction pipe 56H) are provided, and a check valve (in the embodiment, check valves 26, 74, 75, 76) is provided in the middle of the mixture introduction passage. The control means includes a pressurizer (a pump 28 in the embodiment) provided in the mixture introduction passage and located upstream of the check valve, and the pressurizer based on a temperature inside the sub-evaporator. And a pressure control unit (in the embodiment, the pressure control unit 24) for adjusting the pressure in the mixed liquid introduction passage.

The check valve prevents the mixed liquid from flowing backward from the sub-evaporator. When the pressure of the pressurizer becomes higher than the pressure in the sub-evaporator, the check valve is opened and the mixed liquid is supplied to the sub-evaporator. It can be supplied to the evaporator. Therefore, by adjusting the pressure in the mixture introduction passage downstream of the pressurizer in accordance with the temperature inside the sub-evaporator, the pressure in the sub-evaporator is adjusted, and the temperature inside the sub-evaporator is adjusted. Can be supplied to the sub-evaporator. Further, it is preferable that the pressure control unit controls the pressurizer so as to supply a new mixture to the inside of the sub-evaporator after the control valve is opened and the entire amount of the mixture is discharged from the sub-evaporator. Thus, the supply amount of the auxiliary fuel vapor from the sub-evaporator can always be kept constant.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A fuel reformer for a fuel cell according to a first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a fuel reformer 1 for a fuel cell according to a first embodiment of the present invention. FIGS. 2 to 5 show details of a sub-evaporator provided in the fuel reformer 1. The structure is shown.

In FIG. 1, a fuel reformer 1 reforms a raw material gas to generate a reformed gas, and includes a combustor 2 for generating a combustion gas (heating medium), and a heat source for the combustion gas. An evaporator 3 for evaporating a mixture of fuel and water to generate a fuel gas, a reformer 4 for reforming the fuel gas to generate a reformed gas containing hydrogen, and a sub-evaporator 6, The control device 21 is mainly configured.

The combustor 2 is provided with a combustion catalyst (not shown). When the fuel for combustion is supplied to the combustor 2, the fuel for combustion is burned on the catalyst for combustion to generate high-temperature combustion gas. This combustion gas is supplied to the evaporator 3.

The evaporator 3 is provided with an injection device (not shown), and the injection device is provided with a mixed liquid tank 5 via a pipe. The mixed liquid tank 5 is filled with a mixed liquid of fuel and water. As the fuel, for example, methanol is used. The mixed liquid injected into the evaporator 3 from the injection device is evaporated by the heat of the combustion gas to generate a fuel gas. The combustion gas exchanges heat with the mixed liquid, the temperature of which is reduced, and the combustion gas is discharged from the evaporator 3.

The reformer 4 is provided with a reforming catalyst (not shown). The reforming catalyst is heated to 300 ° C. or higher, and fuel gas is supplied to the reformer 4 together with oxygen in the air. Then, on the reforming catalyst, the following reaction formulas (1) to (1)
The reaction shown in (3) proceeds, and a reformed gas is generated.

CH ₃ OH + H ₂ O → 3H ₂ + CO ₂ (1) CH ₃ OH + 2O ₂ → 2H ₂ O + CO ₂ (2) CH ₃ OH → 2H ₂ + CO (3)

Reaction equation (1) shows that methanol as a fuel is
It is a reforming reaction with water and hydrogen (H _Two) Produces and reacts
Equation (2) is an oxidation reaction of methanol, and the water (H
_TwoO) is produced, and the reaction formula (3) is
And a small amount of carbon monoxide (CO) is produced as a by-product. Reform
The reaction (reaction formula (1)) is an endothermic reaction,
Is required, the oxidation of methanol (reaction formula
This is compensated for by the heat of oxidation generated by (2)). this
Including hydrogen, water vapor and traces of carbon monoxide
Reformed gas is generated. Although not shown, the reformer 4
By installing a carbon monoxide remover on the downstream side,
Reforming gas by oxidizing carbon to carbon dioxide
It is preferable to remove carbon monoxide therein.

A fuel cell 11 is connected downstream of the reformer 4. The fuel cell 11 is of a solid polymer type, and is configured by stacking a plurality of stack cells each having a polymer electrolyte membrane sandwiched between an anode and a cathode.
The generated reformed gas is supplied to the anode of the fuel cell 11, and at the same time, air (oxygen) is supplied to the cathode of the fuel cell 11, and the electrochemical reaction between oxygen and hydrogen proceeds to generate power. .

Exhaust gas containing unreacted gas discharged from the fuel cell 11 is supplied to the combustor 2, and the combustor 2 burns the exhaust gas to generate a combustion gas. I have.

A load device 12 such as a motor is connected to the fuel cell 11, and power generated by the fuel cell 11 is supplied to the load device 12 so that the load device 12 operates. .

The sub-evaporator 6 stores a mixed liquid of water and fuel in a heated and pressurized state, and includes a sub-evaporator 7. As shown in FIGS. 2 to 5, the sub-evaporation unit 7 includes a heating passage 31, a heat storage chamber 32, and a mixed liquid chamber 33.

In FIG. 2, the mixed liquid chamber 33 has a heat storage chamber 3
, A plurality of mixed liquid pipes 33A.
Are provided on the lower side in FIG.
The lower mixed liquid tank 33C which communicates with the heat storage chamber 3B.
2 and an upper mixed liquid tank 33E communicating with the other ends 33D of the mixed liquid pipes 33A. Further, a mixed liquid introducing pipe 33F is connected to the lower mixed liquid tank 33C, and an auxiliary vapor outlet pipe 33G is connected to the upper mixed liquid tank 33E. As shown in FIGS. 1 and 2, the mixed liquid tank 5 is connected to the upstream side of the mixed liquid introduction pipe 33F, and the control valve 25 and the evaporator 3 are connected to the downstream side of the auxiliary vapor outlet pipe 33G. Have been.

The mixed liquid is supplied to the mixed liquid chamber 33 from the mixed liquid introducing pipe 33F, and the mixed liquid is supplied to the lower mixed liquid tank 33.
C, a mixed liquid pipe 33A,..., And an upper mixed liquid tank 33E.

In FIG. 2, the heating passage 31 is provided with a plurality of heating pipes 31A... Passing through the heat storage chamber 32 and the upper mixed liquid tank 33E, and a heating pipe provided on the lower side of the lower mixed liquid tank 33C in the drawing. 31A, the lower heating tank 31C communicating with each end 31B, and the upper mixed liquid tank 33.
Each of the other ends 3 of the heating pipes 31A provided on the upper side in FIG.
1D and an upper heating tank 31E communicating with the upper heating tank 31E. A plurality of passage holes 33 are provided in the lower mixed liquid tank 33C.
H are provided, and the heating pipes 31A are connected to the lower heating tank 31C through the through holes 33H. A heating medium outlet pipe 31F is connected to the lower heating tank 31C, and a heating medium introduction pipe 31G is connected to the upper heating tank 32E. 1 and 2
As shown in the figure, the evaporator 3 is connected to the upstream side of the heating medium introduction pipe 31G.

The combustion gas discharged from the evaporator 3 is introduced into the heating passage 31 through the heating medium introduction pipe 31G, and passes through the upper heating tank 31E, the heating pipe 31A..., And the lower heating tank 31C in this order. Have been.

Further, as shown in FIG. 2, the heat storage chamber 32 includes a main heat storage chamber 32A sandwiched between an upper mixed liquid tank 33E and a lower mixed liquid tank 33C, and a lower mixed liquid tank 33C and a lower heated tank 31C. The main heat storage chamber 32A and the sub heat storage chamber 32B are communicated with each other through through holes 33H of a lower mixed liquid tank 33C. Further, a heat storage material introduction pipe 32C is attached to the main heat storage chamber 32A so that the heat storage material can be charged from the outside.

As the heat storage material, for example, a mixture of potassium hydroxide and sodium hydroxide, silicon oil and the like are used.

The control valve 2 is provided in the middle of the auxiliary steam outlet pipe 33G.
The control valve 25 is provided with a control device 21.
Are connected to the adjustment unit 22 and the temperature control unit 23. A pump 28 as a pressurizer is provided in the middle of the mixture introduction pipe 33F, and a check valve 26 (a check valve) is provided on the downstream side of the pump 28. It is connected to the control unit 24. The check valve 26 prevents the mixed liquid from flowing backward from the sub-evaporator 6 (mixed liquid chamber 33). When the pressure in the mixed liquid chamber 33 decreases, the check valve 26 opens to allow the mixed liquid to flow. 3
3 is supplied.

Further, a thermometer 27 which is a temperature detector for detecting the temperature of the heat storage material is attached to the sub-evaporator 6, and the thermometer 27 includes a temperature control unit 23 and a pressure control unit 2.
4 is connected. These control valve 25, pump 28,
The control unit is configured by the adjustment unit 22, the temperature control unit 23, and the pressure control unit 24.

When a signal for requesting an increase in the amount of reformed gas generated is input, the adjusting unit 22 opens the control valve 25 based on the required value of the signal, and controls the mixed liquid in the heated and pressurized state. The fuel is evaporated under reduced pressure to form auxiliary fuel vapor, and the auxiliary fuel vapor is supplied to the evaporator 3. When the temperature of the heat storage material reaches the heat storage upper limit temperature, the temperature control unit 23 opens the control valve 25 to supply the heated and pressurized mixture to the evaporator 3. The maximum heat storage temperature varies depending on the type of heat storage material.
The range is 0 to 250 ° C. Further, the pressure control unit 24
Controls the pressure of the mixture in the mixture introduction pipe 33F downstream of the pump 28 by controlling the pump 28 based on the open / close state of the control valve 25 and the temperature of the heat storage material. Further, the pressure control unit 24 controls the pump 28 so as to supply a new mixture to the inside of the sub-evaporator 6 after the control valve 25 is opened and the entire amount of the mixture is discharged from the sub-evaporator 6. Is configured.

Next, the operation of the fuel reformer 1 for a fuel cell will be described. First, the mixed liquid is supplied from the mixed liquid tank 5 to the evaporator 3, and the mixed liquid is evaporated by the heat of the combustion gas supplied from the combustor 2 to the evaporator 3 to generate a fuel gas.

The fuel gas generated by the evaporator is supplied to the reformer 4
And the reforming reaction represented by the above-mentioned reaction formulas (1) to (3) proceeds on the reforming catalyst provided in the reformer 4 to generate a reformed gas containing hydrogen. The reformed gas is supplied to the anode of the fuel cell 11 and the fuel cell 11 generates power. The electric power obtained by the power generation
2 to drive the load device 12.

The mixed liquid is filled from the mixed liquid tank 5 into the mixed liquid chamber 33 of the sub-evaporator 6 through the mixed liquid introducing pipe 33F, the pump 28 and the check valve 26. Mixed liquid chamber 33
Is performed by controlling the pump 28 by the pressure control unit 24. The pressure at this time is 10 kPa to 2 M
It is preferable to set the range of Pa.

At the same time, the combustion gas discharged from the evaporator 3 is supplied to the heating passage 31 of the sub-evaporator 6 through the heating introduction pipe 31G.
And discharged from the heating outlet pipe 31F. When the combustion gas passes through the heating passage 31, heat exchange is performed with the heat storage material filled in the heat storage chamber 32, and the heat storage material is heated. Further, by performing heat exchange between the heat storage material and the mixed liquid, the mixed liquid is heated, and the mixed liquid is heated and pressurized. The temperature of the mixture at this time is preferably in the range of 130 to 230 ° C., and the pressure of the mixture is 10 kP
It is preferably in the range of a to 2 MPa.

Here, when a large load is applied to the load device 12, it is necessary to increase the electric power supplied from the fuel cell 11 to the load device 12. For that purpose, it is necessary to increase the amount of reformed gas generated in the fuel reformer 1. In the fuel reforming apparatus 1 of the present invention, when there is a request to increase the reformed gas generation amount due to a change in the load amount, the control device 21
The request signal is input to the adjustment unit 22 of. Then, an operation signal is sent from the adjustment unit 22 to the control valve 25, and the control valve 25 is in an “open” state. As a result, the mixed liquid stored in the mixed liquid chamber 33 in a heated and pressurized state is evaporated under reduced pressure in the auxiliary vapor outlet pipe 33G to become auxiliary fuel vapor, and this auxiliary fuel vapor is supplied to the evaporator 3. When the auxiliary fuel vapor is supplied from the liquid mixture chamber 33 to the auxiliary vapor outlet pipe 33G, the pressure of the liquid mixture sharply decreases, so that the liquid mixture is evaporated under reduced pressure. This auxiliary fuel vapor is reheated in the evaporator 3 to generate new fuel gas. Control valve 2
After 5 is opened and the entire amount of the mixed liquid is discharged, the pump 28 is operated by the pressure control unit 24, and a new mixed liquid is supplied into the sub-evaporator.

In this way, in addition to the fuel gas normally generated in the evaporator 3, the evaporator 3
Since the fuel gas is generated by the auxiliary fuel vapor supplied to the control device 21, it is possible to temporarily increase the amount of the fuel gas as compared to before the increase signal is input to the control device 21,
As a result, the amount of reformed gas generated can be temporarily increased. Thus, when a large load is applied to the load device 12, the power generation amount of the fuel cell 11 can be immediately increased, and the load responsiveness of the fuel reformer 1 can be improved. Therefore, the fuel reforming apparatus 1 of the present invention
Is adopted in a fuel cell system, unlike a conventional fuel cell system, there is no need to provide a large-capacity secondary battery serving as a power buffer, and the fuel cell system can be downsized.

Further, by performing heat exchange between the combustion gas and the mixed liquid via the heat storage material, the mixed liquid can be efficiently heated by the heat of the combustion gas. Further, the combustion gas is introduced into the evaporator 3 to evaporate water and fuel,
Since the heating medium is introduced into the heating passage 31 of the sub-evaporator 7, the heating medium can be reused in the sub-evaporator 6, and the thermal efficiency of the fuel reformer 1 can be improved.

Since the evaporator 3 is configured to heat the heated and pressurized mixture supplied from the sub-evaporator 6, the mixture supplied from the sub-evaporator 6 is evaporated under reduced pressure. At the same time, the fuel gas is heated by the evaporator 3 and turned into a high-temperature fuel gas, so that the thermal efficiency of the fuel reformer 1 can be improved.

If the load of the load device 12 is kept constant for a long period of time, the mixed liquid is heated and pressurized in the sub-evaporator 6.
For a long time. During this time, the combustion gas continues to be supplied to the sub-evaporator 6, so that the temperature of the heat storage material inside the sub-evaporator 6 gradually increases. When the temperature of the heat storage material detected by the thermometer 27 exceeds the heat storage upper limit temperature,
An operation signal is sent from the temperature control unit 23 of the control device 21 to the control valve 25, and the control valve 25 is in an "open" state.
Thus, the mixed liquid stored in the mixed liquid chamber 33 in a heated and pressurized state is blown out to the evaporator 3 through the auxiliary vapor outlet pipe 33G, and the heat storage material is cooled by the reduced pressure evaporation of the mixed liquid, The temperature of the sub-evaporator 6 becomes lower than the heat storage upper limit temperature, so that it is possible to prevent the temperature of the heat storage material from rising excessively, and it is possible to prevent the temperature of the sub-evaporator 6 from rising excessively.
Such a state is likely to occur during a high load operation of the fuel cell, and when an excessive temperature rise of the sub-evaporator 6 occurs, the amount of fuel directly supplied to the evaporator 3 is reduced from the sub-evaporator 6. It may be a value that is smaller than the supplied auxiliary fuel vapor amount.

By the way, the request time of the increase of the reformed gas is often random, and therefore, the storage time in which the mixed liquid is stored in the mixed liquid chamber is not always constant, and therefore,
The temperature of the heat storage material will always fluctuate. Therefore, to always fill the mixed liquid chamber with a fixed amount of the mixed liquid in this state,
It is necessary to change the filling pressure of the mixed liquid depending on the temperature of the heat storage material inside the sub-evaporator 6. In the fuel reformer 1 of the present invention,
When a new mixed liquid is supplied to the mixed liquid chamber 33, the pump 28 is controlled according to the temperature inside the sub-evaporator 6 (heat storage material) to adjust the pressure of the mixed liquid introduction pipe 33F downstream of the pump 28. I do. For example, when the temperature of the heat storage material is high, the pressure of the mixed liquid introduction pipe 33F is increased, and when the temperature of the heat storage material is low, the pressure of the mixed liquid introduction pipe 33F is reduced.

The mixed liquid introduction pipe 33F on the downstream side of the pump 28
Is provided with a check valve 26, the pressure of the mixed liquid chamber 33 becomes equal to the pressure of the mixed liquid inlet pipe 33F downstream of the pump 28, and the pressure of the mixed liquid inlet pipe 33F is changed according to the temperature of the heat storage material. By adjusting the pressure, the pressure of the mixed liquid chamber 33 can be adjusted, and the amount of the mixed liquid to be filled in the mixed liquid chamber 33 can always be constant regardless of the temperature of the heat storage material.

Next, a fuel reforming apparatus 51 according to a second embodiment of the present invention will be described with reference to FIGS.
In these drawings, the same components as those shown in FIGS. 1 to 4 are denoted by the same reference numerals, and the description thereof will be simplified or the description will be omitted.

The fuel reformer 51 is provided with a sub-evaporator 56 having three sub-evaporators 7A, 7B and 7C. As shown in FIG. 6, the sub-evaporator 56 is configured by stacking three sub-evaporators 7A, 7B, and 7C. These sub-evaporators 7A, 7B, 7C have the same structure as the sub-evaporator 7 in the fuel reformer 1 described above. The sub-evaporator 56 includes a heating introduction pipe 56A for introducing combustion gas from the evaporator 3, and each sub-evaporator 7A,
A mixed liquid introduction tube 56B, 5B for introducing the mixed liquid into 7B, 7C.
6C, 56D, and auxiliary steam derivation pipes 56E, 56 for deriving the mixed liquid from each of the sub-evaporators 7A, 7B, 7C in a vapor state.
F, 56G are connected. Further, a discharge pipe 56J connecting each of the auxiliary vapor discharge pipes 56E, 56F, 56G to the evaporator 3, a mixed liquid tank 5, a mixed liquid introduction pipe 56B, and a mixed liquid introduction pipe 56B,
An introduction pipe 56H for connecting 6C and 56D is provided.

Each auxiliary steam outlet pipe 56E, 56F,
Control valves 71, 72, 73 are provided in the middle of 56G, and each of the control valves 71, 72, 73 is connected to the adjustment unit 62 and the temperature control unit 23 of the control device 61. Further, a pump 28 as a pressurizer is provided in the middle of the introduction pipe 56H, and the pump 28 is connected to the pressure control unit 24 of the control device 61. Check valves 74, 75, and 76, which are check valves, are provided in the mixed liquid introduction pipes 56B, 56C, and 56D downstream of the pump 28, respectively. These check valves 74, 75, 76 are the same as the check valve 26 described above.

When a signal for requesting an increase in the amount of reformed gas generated is input, the adjusting section 62 opens part or all of the check valves 74, 75, and 76 based on the request value of the signal. Thereby, the supply amount of the auxiliary fuel vapor to the evaporator 3 is adjusted.

Further, the sub-evaporator 56 has a thermometer 2 as a temperature detector for detecting the temperature of the heat storage material inside the sub-evaporator 56.
The thermometer 27 is connected to the temperature control unit 23 and the pressure control unit 24. These control valves 71, 72, 73, the pump 28, the adjusting unit 62, the temperature control unit 23, and the pressure control unit 24 constitute a control unit.

Next, the operation of the fuel reformer 51 will be described focusing on the operation of the sub-evaporator 56. The mixed liquid is supplied from the mixed liquid tank 5 to the pump 28 and the check valves 74 and 7.
5 and 76, the respective sub-evaporators 7A, 7B and 7 of the sub-evaporator 6
Fill each mixed liquid chamber of C. The filling pressure of the mixture is controlled by controlling the pump 28 by the pressure control unit 24.
The filling pressure at this time is preferably in the range of 10 kPa to 2 MPa.

At the same time, the combustion gas discharged from the evaporator 3 is passed through the heating passage of the sub-evaporator 56 via the heating introduction pipe 56A. When the combustion gas passes through the heating passage, heat exchange is performed with the heat storage material to heat the heat storage material. Then, heat exchange is performed between the heat storage material and the mixed liquid filled in the mixed liquid chamber, whereby the mixed liquid is heated, and the mixed liquid is heated and pressurized. At this time, the temperature of the mixture was 13
The pressure is preferably in the range of 0 to 230 ° C, and the pressure of the mixed solution is preferably in the range of 10 kPa to 2 MPa.

When there is a request to increase the amount of reformed gas generated due to a change in the load, a request signal is input to the adjusting unit 62 of the control device 61. The request signal has one of the request values “1”, “2”, and “3” depending on the magnitude of the load. Here, the required value is set to increase as the magnitude of the load increases. Based on the input request signal, the adjusting unit 62 sets only the control valve 71 to the “open” state when the request value is “1”, for example, and sets the two control valves when the request value is “2”. 71, 72
Is set to the "open" state, and when the required value is "3", all the control valves 71, 72, 73 are set to the "open" state.
An operation signal is sent to each of the control valves 71, 72, 73.

Thus, each of the sub-evaporators 7A, 7B, 7C
A part or the whole of the mixed liquid stored in the heated and pressurized state is evaporated under reduced pressure in the auxiliary vapor outlet pipes 56E, 56F, 56G to become auxiliary fuel vapor, and this auxiliary fuel vapor is supplied to the evaporator 3. . Auxiliary fuel vapor flows from each of the sub-evaporators 7A, 7B, 7C to auxiliary vapor outlet pipes 56E, 56F,
When supplied to 56G, the pressure of the mixed liquid drops rapidly, so that the mixed liquid is evaporated under reduced pressure to become auxiliary fuel vapor. This auxiliary fuel vapor is reheated in the evaporator 3 to generate new fuel gas.

As described above, in addition to the fuel gas normally generated in the evaporator 3, the fuel gas is generated by the auxiliary fuel vapor supplied from the sub-evaporator 56 to the evaporator 3. Can be temporarily increased as compared to before the increase signal is input to the control device 61, whereby the generation amount of the reformed gas can be temporarily increased. Thus, when a large load is applied to the load device 12, the power generation amount of the fuel cell 11 can be immediately increased, and the load responsiveness of the fuel reforming device 51 can be improved. Therefore, when the fuel reforming apparatus 51 of the present invention is used in a fuel cell system, unlike the conventional fuel cell system, it is not necessary to provide a large-capacity secondary battery serving as an electric power buffer. The size can be reduced.

In particular, in the above-described fuel reforming apparatus 51, the control valves 74, 75, 76 correspond to the required amount of reformed gas.
The auxiliary fuel vapor is supplied to the evaporator 3 by opening a part or all of the auxiliary fuel vapor, so that the amount of newly added auxiliary fuel vapor can be adjusted by the number of control valves to be operated. It is possible to generate an amount of fuel gas according to the required amount of the quality gas.

Further, by performing heat exchange between the combustion gas and the mixed liquid via the heat storage material, the mixed liquid can be efficiently heated by the heat of the combustion gas. Further, the combustion gas is introduced into the evaporator 3 to evaporate water and fuel,
Since the heating medium is introduced into the sub-evaporators 7A, 7B and 7C, the heating medium can be reused in the sub-evaporators 7A, 7B and 7C,
The thermal efficiency of the fuel reformer 51 can be improved.

Since the evaporator 3 is configured to heat the auxiliary fuel vapor, the mixed liquid supplied from the sub-evaporator 56 is heated by the evaporator 3 at the same time when the mixed liquid supplied from the sub-evaporator 56 is evaporated under reduced pressure. And the thermal efficiency of the fuel reformer 51 can be improved.

When the temperature of the heat storage material inside the sub-evaporator 56 exceeds the heat storage upper limit temperature, the temperature control unit 2 of the control device 61
An operation signal is sent from 3 to a part or all of the control valves 71, 72, 73, and a part or all of the control valves 71, 72, 73 is in an "open" state. As a result, part or all of the mixed liquid stored in each of the sub-evaporators 7A, 7B, 7C in a heated and pressurized state is jetted to the evaporator 3, and the heat storage material is cooled by the reduced-pressure evaporation of the mixed liquid Then, the temperature of the sub-evaporator 56 becomes lower than the heat storage upper limit temperature, so that an excessive temperature rise of the heat storage material can be prevented, and an excessive temperature rise of the sub-evaporator 56 can be prevented. Such a state is likely to occur during a high-load operation of the fuel cell, and when an excessive temperature rise of the sub-evaporator 56 occurs, the amount of fuel directly supplied to the evaporator 3 is reduced from the sub-evaporator 56. It may be a value that is smaller than the supplied auxiliary fuel vapor amount.

By the way, the request time for the increase in the supply amount of the reformed gas is often random, and therefore, the storage time in which the mixed liquid is stored in the sub-evaporators 7A, 7B, 7C is not always constant, and therefore, The temperature of the heat storage material will always fluctuate. In addition, the number of sub-evaporation units that operate when the request signal is input changes depending on the request value of the operation signal, so that the temperature of the heat storage material also constantly changes.

In this state, in order to always fill the sub-evaporation sections 7A, 7B, 7C with a fixed amount of the liquid mixture, it is necessary to change the filling pressure of the liquid mixture depending on the temperature of the heat storage material. In the fuel reformer 51, the new mixed liquid is supplied to the sub-evaporators 7A, 7B,
7C, the pump 28 is controlled according to the temperature of the heat storage material, and the mixed liquid introduction pipe 7 downstream of the pump 28 is controlled.
4. Adjust the pressure at 75, 76. For example, when the temperature of the heat storage material is high, the pressure of the mixed liquid introduction pipes 74, 75, 76 is increased, and when the temperature of the heat storage material is low, the mixed liquid introduction pipe 74,
The pressure at 75 and 76 is reduced. By doing this,
The amount of the mixed liquid filled in each of the sub-evaporation sections 7A, 7B, 7C is
It can be kept constant regardless of the temperature of the heat storage material.

[0067]

As described above, the fuel reformer for a fuel cell according to the present invention has a sub-evaporator for storing a mixed solution in a heated and pressurized state and a demand for increasing the amount of reformed gas generated. Control means for supplying the mixed liquid to the evaporator as auxiliary fuel vapor, so that when there is a request to increase the amount of reformed gas generated, additional fuel gas is supplied from the sub-evaporator As a result, the amount of reformed gas generated can be increased, and the responsiveness to a change in the load of the fuel cell can be increased. Therefore, when the fuel reforming apparatus of the present invention is used in a fuel cell system, unlike the conventional fuel cell system, it is not necessary to provide a large-capacity secondary battery serving as an electric power buffer, and the fuel cell system can be reduced in size. Can be

Further, the fuel reformer for a fuel cell of the present invention is provided with a combustor for generating a heating medium, and the heating medium is introduced into the sub-evaporator via the evaporator. Therefore, the heating medium can be reused in the sub-evaporator, and the thermal efficiency of the fuel reformer can be improved.

Further, since the evaporator is configured to heat the auxiliary fuel vapor, the auxiliary fuel vapor supplied from the sub-evaporator can be used as high-temperature fuel gas.
The thermal efficiency of the fuel reformer can be improved.

Further, the control means includes a pressurizer and a pressure controller for controlling the pressurizer based on the temperature inside the sub-evaporator. The pressure in the mixed liquid chamber can be adjusted by adjusting the pressure in the mixed liquid introduction passage downstream of the pressurizer, so that the mixed liquid can be supplied to the sub-evaporator even if the temperature inside the sub-evaporator changes. The amount can always be constant.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a configuration of a fuel reformer for a fuel cell according to a first embodiment of the present invention.

FIG. 2 is a front sectional view of a sub-evaporator of the fuel reformer shown in FIG.

FIG. 3 is a top sectional view of a sub-evaporator of the fuel reformer shown in FIG.

FIG. 4 is a side sectional view of a sub-evaporator of the fuel reformer shown in FIG.

FIG. 5 is a configuration diagram illustrating a configuration of a fuel reformer for a fuel cell according to a second embodiment of the present invention.

FIG. 6 is a front sectional view of a sub-evaporator of the fuel reformer shown in FIG.

FIG. 7 is a configuration diagram showing a configuration of a fuel cell system including a conventional fuel cell fuel reformer.

[Explanation of symbols]

1, 51: fuel reformer for fuel cell, 2: combustor, 3 ...
Evaporator, 4 ... reformer, 6, 56 ... sub-evaporator, 7, 7A,
7B, 7C: sub-evaporation unit, 11: fuel cell, 12: load device, 22, 62: adjustment unit (control unit), 23: temperature control unit (control unit), 24: pressure control unit (control unit), 2
5, 71, 72, 73 ... control valve (control means), 26, 7
4, 75, 76: check valve (check valve), 27: thermometer (temperature detector (control means)), 28: pump (pressurizer (control means)), 31: heating passage, 32: heat storage chamber, 3
3: mixed liquid chamber, 33F, 56B, 56C, 56D: mixed liquid introduction pipe (mixed liquid introduction passage)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yuji Asano 1-4-1 Chuo, Wako-shi, Saitama Prefecture Inside Honda R & D Co., Ltd. (72) Takahiro Tachihara 1-4-1 Chuo, Wako-shi, Saitama F-term in Honda R & D Co., Ltd. (reference) 5H027 AA06 BA01 KK05 KK41 MM09 MM16

Claims (4)

[Claims] 1. A fuel cell comprising: an evaporator for evaporating water and fuel to generate a fuel gas; and a reformer for reforming the fuel gas to generate a reformed gas containing hydrogen. A fuel reformer, comprising: a sub-evaporator for storing a mixed liquid of water and fuel in a heated and pressurized state; Control means for supplying auxiliary fuel vapor generated by evaporation to the evaporator, wherein the fuel reformer for a fuel cell is provided. 2. The evaporator is provided with a combustor for generating a heating medium, and the heating medium is configured to be introduced into the sub-evaporator via the evaporator. 2. The fuel reformer for a fuel cell according to claim 1. 3. The fuel reformer for a fuel cell according to claim 1, wherein the evaporator is configured to heat the auxiliary fuel vapor supplied from the sub-evaporator. 4. A mixed liquid introduction passage is provided on the inlet side of the sub-evaporator, a check valve is provided in the middle of the mixed liquid introduction passage, and the control means is provided in the mixed liquid introduction passage. And a pressure control unit that controls the pressurizer based on the temperature inside the sub-evaporator to adjust the pressure in the mixed liquid introduction passage based on the temperature inside the sub-evaporator. The fuel reformer for a fuel cell according to claim 1, wherein: