JP2002154807A - Reforming system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reforming system, in which damage to a catalyst and the heat strain of an apparatus are prevented by preventing the radical change of the temperature in the system when the operation is stopped and simultaneously the entering of air from the outside is easily prevented. SOLUTION: In the reforming system provided with a reformer 6 for producing a reformed gas by reforming fuel and a power source 8 working by using the reformed gas produced in the reformer as fuel, a refluxing passage for refluxing an exhaust gas to the reformer from valves V6 and V7 when the operation is stopped is formed and a gas circulating passage is formed by sealing the gas in the system by valves V1, V3, V4, V6 and V7 and the sealed gas is circulated by a pump 12. It is prevented that the pressure in the system becomes negative by controlling the quantity of the combustion gas (exhaust gas produced in the reforming system) produced in a combustor 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reforming system including a reformer for producing a reformed gas from a hydrocarbon fuel and a power source operating with the reformed gas as a fuel. Related to shutdown technology.

[0002]

2. Description of the Related Art As a technique for stopping the operation of a reforming system, there is known a technique in which an exhaust gas of a fuel cell is subjected to a combustion treatment, and then an inert gas obtained by removing oxygen gas is used to remove the reformed gas remaining in the system. Reforming remaining in the system using a replacement gas (see Japanese Patent Application Laid-Open No. 6-203865) or an inert gas (combustion exhaust gas) obtained by burning a hydrocarbon fuel as a raw material of the reformed gas. Replacement with gas (Japanese Unexamined Patent Publication No. 8-7)
No. 8037).

[0003]

However, in the above prior art, in order to prepare a sufficient amount of inert gas to replace the entire system, the former requires installation of a tank for storing the inert gas. The latter requires the use of a large capacity combustor. For this reason, the size of the system is increased, and there is a problem particularly as a vehicle-mounted system that requires a reduction in size.

[0004] Further, since the gas flow in the system stops when the system stops operating, in a reforming system that operates at a high temperature, the temperature in the system rises sharply to damage the catalyst, or the low-temperature inertness occurs. Immediately after the gas is charged, the temperature in the system suddenly drops, and thereafter, the temperature rises sharply as described above, so that there has been a problem that the temperature change is large and thermal distortion occurs in the apparatus.

Further, since the pressure in the system becomes negative due to a decrease in the temperature inside the system immediately after the filling of the inert gas, an expensive piping system is required to prevent intrusion of air from the outside. Therefore, the present invention has been made in view of the above-described conventional problems, and aims to reduce the size of the system, prevent a sudden change in the temperature in the system when the operation is stopped, and prevent damage to the catalyst and the device. It is an object of the present invention to provide a reforming system capable of preventing heat distortion of the slag and further easily preventing the invasion of air from the outside.

[0006]

SUMMARY OF THE INVENTION Therefore, the invention according to claim 1 comprises a reformer for reforming a hydrocarbon fuel to produce a reformed gas, and a reformer for producing a reformed gas from the reformer. A power source that operates as a fuel, and in a reforming system, the system is annularly sealed so that exhaust gas generated by the reforming system when operation is stopped is returned to the reformer, The gas is circulated by a pump.

According to a second aspect of the present invention, in the first aspect of the present invention, the pressure in the reforming system is made equal to or higher than the atmospheric pressure by controlling the amount of exhaust gas generated in the reforming system. It is characterized by. According to a third aspect of the present invention, in the first or second aspect of the present invention, the pump for circulating the sealed gas also serves as an air pump for sending air to the reformer during operation. .

According to a fourth aspect of the present invention, in the first aspect of the present invention, the cooling rate of the system is controlled by adjusting the flow velocity of the gas circulating in the system. It is characterized by. The invention according to claim 5 is the invention according to any one of claims 1 to 4, further comprising a cooling device for cooling gas circulating in the system.

According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the temperature of the gas circulating in the system is controlled by adjusting the flow rate of the refrigerant in the cooling device. The invention according to claim 7 is characterized in that, in the invention according to claim 5 or 6, the waste heat of the cooling device is used in the reforming system.

The invention according to claim 8 is the invention according to any one of claims 1 to 7, wherein the power source is a fuel cell, and the exhaust gas is an exhaust gas from the fuel cell or a combustion gas of the exhaust gas. It is characterized by being. According to a ninth aspect of the present invention, in the invention according to any one of the first to seventh aspects, the power source uses at least one of a reformed gas and a hydrocarbon fuel used as a raw material of the reformed gas as a fuel. And the exhaust gas is exhaust gas from the engine.

According to a tenth aspect of the present invention, in the invention according to any one of the first to ninth aspects, the reformer performs a steam reforming reaction with a hydrocarbon fuel and water. And The invention according to claim 11 is the invention according to claim 10
In the invention according to the first aspect, waste heat of the power source is supplied to the reformer.

[0012] According to a twelfth aspect of the present invention, in the invention according to the eleventh aspect, when the waste heat of the supplied power source is insufficient, the reformer is configured to use a part of the hydrocarbon fuel and the air to partially generate the waste heat. It is characterized by being supplemented by performing an oxidation reaction.

[0013]

According to the first aspect of the present invention, the exhaust gas generated in the reforming system is annularly sealed in the system so that the exhaust gas is returned to the reformer. Since both the reformed gas and the reformed gas are sealed in the system, a space for preparing an inert gas or a combustor having a large capacity is not required in advance, and the system can be downsized. In addition, since the gas sealed in the system is circulated by the pump, the sealed residual reformed gas is consumed and a rapid change in the temperature in the system can be suppressed.
Damage to the catalyst and thermal distortion of the device can be prevented.

According to the second aspect of the present invention, by controlling the amount of exhaust gas generated in the reforming system, the pressure in the system is prevented from becoming negative and is set to be higher than the atmospheric pressure. Air can easily be prevented from entering the system from the inside. According to the third aspect of the present invention, an air pump for supplying air to the reformer during operation is also used as a gas circulation pump in the system, so that an air pump dedicated to circulation can be omitted.

According to the fourth aspect of the present invention, since the cooling efficiency can be adjusted by adjusting the flow velocity of the gas flowing in the circulation path, the cooling rate of the system can be controlled. According to the fifth aspect of the present invention, since the temperature in the system can be adjusted by the cooling device, the cooling rate of the system can be controlled.

According to the invention of claim 6, since the cooling efficiency of the gas circulating in the system can be adjusted by adjusting the flow rate of the refrigerant in the cooling device, the cooling rate of the system can be controlled. According to the invention according to claim 7, the energy efficiency can be improved by using the waste heat of the cooler in a system device such as a vaporizer.

According to the eighth aspect of the invention, by using the exhaust gas on the fuel electrode side of the fuel cell or the combustion gas of the exhaust gas, the size of the system can be reduced, and damage when the system is stopped can be prevented. According to the invention according to claim 9,
By using the exhaust gas of the engine, the size of the system can be reduced, and damage when the system is stopped can be reliably prevented.

According to the tenth aspect of the present invention, a reformed gas which is a fuel of a power source can be generated by performing a steam reforming reaction between a hydrocarbon fuel and water. According to the eleventh aspect of the present invention, since the steam reforming reaction between the hydrocarbon fuel and water is an endothermic reaction, by supplying waste heat of the power source to the reformer, energy efficiency is improved, and Waste heat recovery of the source can be performed.

According to the twelfth aspect, when the calorific value of the waste heat of the power source to be supplied is insufficient, a partial oxidation reaction by a part of the hydrocarbon fuel which is an exothermic reaction and air is performed. , Can compensate for the shortage of heat.

[0020]

Embodiments of the present invention will be described below. FIG. 1 is an embodiment of a reforming system using a fuel cell as a power source. As shown in FIG. 1, the reforming system includes a fuel tank 1, a water tank 2, liquid sending pumps 3, 4, a vaporizer 5, a thermometer T1, a reformer 6, a carbon monoxide removing device 7, a fuel cell 8, , Water recovery device 9, combustor 10,
A cooling device 11, a pump 12 for sending air to the reformer 6, and flow passage switching valves (V1 to V4, V
6, V7) and stop valves (V5, V8).

The hydrocarbon fuel in the fuel tank 1 is sent to the vaporizer 5 by the liquid feed pump 3 and the water in the water tank 2 is sent to the vaporizer 5 by the liquid feed pump 4. The vaporizer 5 vaporizes and mixes the hydrocarbon fuel and water to generate a raw material gas. Vaporizer 5 and valve V
The reformer 6 communicating via 1 reforms the raw material gas into a gas containing hydrogen and carbon monoxide as main components (reformed gas).

The reformed gas, from which carbon monoxide is removed by a carbon monoxide removing device 7, is sent to a fuel cell 8. Fuel cell 8
Generates electricity by reacting reformed gas (hydrogen) supplied to the fuel electrode side with oxygen in the air supplied to the air electrode side by a pump (not shown). Here, in the present system, a polymer electrolyte fuel cell (PEFC) is used as the fuel cell 8.

A valve V3 is provided in an exhaust flow path on the fuel electrode side of the fuel cell 8, and a water recovery device 9 is provided by switching.
Alternatively, a flow path to the combustor 10 located downstream thereof is formed. The exhaust passage on the air electrode side of the fuel cell 8 has a valve V2
Is provided, and a water recovery device or a flow path to the outside is formed by switching. A valve V4 is provided on the downstream side of the water recovery device 9, and a flow path to the combustor 10 or the outside is formed by switching.

The combustor 10 is configured so that air is supplied through a valve V5 and fuel is supplied through a valve V8. The combustor 10 combusts exhaust gas containing unconsumed hydrogen from the fuel cell 8. The cooling device 11 is provided on the downstream side of the combustor 10 and cools combustion-treated exhaust gas (combustion exhaust gas). The cooling device 11 has a heat exchange function, and is configured so that waste heat is used in the vaporizer 5 and the like.

A valve V6 is provided downstream of the cooling device 11, and by switching the valve V6, a flow path to the outside or to the valve V7 is formed. Therefore, in the present embodiment, by connecting the valve V6 and the valve V7, a recirculation path for recirculating the combustion gas obtained by burning the exhaust gas of the fuel cell to the reformer 6 is formed. The operation of the reforming system configured as described above during operation will be described.

The raw material gas generated by the vaporizer 5 has a valve V
1, the air is sent to the reformer 6 by the pump 12 through the valve V7 and the valve V1. After the raw material gas is reformed in the reformer 6 to remove carbon monoxide, it is sent to the fuel electrode side of the fuel cell 8. Here, in the PEFC, during system operation, water is generated on the air electrode side, and no water is generated on the fuel electrode side.

Therefore, since the exhaust gas on the fuel electrode side of the fuel cell 8 does not contain moisture but contains hydrogen that has not been consumed by the fuel cell 8, it is sent to the combustor 10 through the valve V3 and consumed hydrogen. Thereafter, the gas is discharged to the outside via the cooling device 11 and the valve V6. On the other hand, since the exhaust gas on the air electrode side of the fuel cell 8 contains moisture, it is sent to the moisture recovery device 9 through the valve V2, and after the moisture is recovered, the valve V4
Is discharged to the outside through

Next, the operation when the operation is stopped will be described with reference to the flowchart of FIG. Step 1 (S in the figure)
Write 1. In response to the command to cut off the supply of the raw material (gas) to the reformer 6 in step 2), in step 2, the vaporizer 5 side of the valve V1 is closed to cut off the supply of the raw material to the system, and the flow path side ( The pump 12 side) is kept open.

In step 3, the exhaust (external) side of the valve V2 provided in the exhaust passage of the air side electrode of the fuel cell 8 is opened, and the water recovery device 9 side is closed. That is, in PEFC, water is not generated on the air electrode side during operation stop,
The water is discharged to the outside without passing through the water recovery device 9. In step 4, the water recovery device 9 side of the valve V3 provided in the exhaust flow path on the fuel electrode side of the fuel cell 8 is opened, and the combustor 10 side is closed. As a result, since the exhaust flow path on the fuel electrode side during the operation stop passes through the water recovery device 9, water generated when the residual reformed gas is burned in the combustor 10 is removed from the line to remove the water. Catalyst damage due to condensation can be prevented.

In step 5, the water recovery device 9 and the combustor 1
The combustor 10 side of the valve V4 provided between 0 is opened, and the exhaust side is closed. In Step 6, the recirculation path side (the valve V7 side) of the valve V6 provided downstream of the cooling device 11 is opened, and the exhaust side is closed. In step 7, the air side of the valve V7 is closed, and the recirculation path side (the valve V6 side) is opened.

By the above steps 2 to 7,
The valve V6 and the valve V7 form a recirculation path for returning the combustion gas of the exhaust gas of the fuel cell 8 to the reformer, and the valves V1, V3, V4, V6, and V7 allow the combustion gas, which is an inert gas, in the system. The residual reformed gas is sealed in the system to form a gas circulation path. As a result, it is not necessary to use a tank for storing the inert gas or a large capacity combustor, and the system can be downsized.

By circulating the gas in the system by the pump 12, rapid changes in the temperature in the system can be suppressed, and damage to the catalyst and thermal distortion of the device can be prevented. Further, while the residual reformed gas is consumed by the circulation, the ratio of the exhaust gas is increased, and the system is cooled by the control described later to stop the operation. In step 8, the temperature T in the gas circulation path is measured by the thermometer T1.

In step 9, the number of moles ng of gas present in the circulation path is calculated from the measured temperature T in the circulation path. In step 10, at room temperature, the number of moles (target mole number n) for maintaining the pressure in the circulation path at about atmospheric pressure.
By subtracting ng of the number of moles in the circulation path calculated in step 9 from t), the gas shortage n (= nt−ng) is calculated.

In step 11, the supply time t of the fuel and air to be supplied to the combustor 10 is determined in order to generate the combustion gas that compensates for the gas shortage n. That is, since the flow rates of the fuel and the air supplied to the combustor 10 are fixed, the supply amounts are adjusted by changing the supply time t. In step 12, the valve 8 and the valve 5 are opened for the supply time t, and fuel and air are supplied to the combustor 10 and burned, thereby generating combustion exhaust gas.

As described above, by the steps 8 to 12,
By maintaining the pressure in the system at or above the atmospheric pressure, intrusion of air from the outside can be easily prevented. Next, the cooling control of the reforming system will be described. In the present embodiment, the flow rate (flow rate) of the circulating gas is adjusted by the reformer 6 during operation.
This is controlled by the pump 12 that sends air to the circulation path so that the temperature change ΔT in the circulation path per predetermined time approaches the target change ΔTt. FIG. 3 shows specific control.

In step 21, the temperature in the circulation path is measured by the thermometer T1. In step 22, the amount of change ΔT in temperature in the circulation path per predetermined time is calculated. Step 2
In step 3, the flow rate after correction Fc is calculated by equation (1), where Fc0 is the circulating gas flow rate before correction and c is the correction gain. Fc = Fc0 + c × (△ Tt- △ T) (1) In step 24, the pump 12 is adjusted based on the calculated corrected flow rate Fc. Here, the flow rates Fc, Fc0
Is measured by a flow meter (not shown) or determined by a method such as measuring the rotation speed of the pump 12 and referring to a flow rate map correlated with the rotation speed.

In step 25, it is determined whether or not the temperature in the circulation path has become equal to or lower than the target temperature Tt. If the temperature in the circulation path has become equal to or lower than the target temperature Tt, the routine proceeds to step 26, where the pump 12 is stopped. . If the temperature in the circulation path is not lower than the predetermined temperature T1, the process returns to step 21 and the flow rate of the circulation gas is adjusted again to cool the system. As described above, the cooling rate of the system can be optimally controlled.

The temperature of the circulating gas may be controlled by a cooling device to control the cooling rate of the system. The system in this case is shown in FIG. 4 that are common to those in FIG. 1 are denoted by the same reference numerals. In the present embodiment, the cooling of the circulating gas is performed by sending the refrigerant that has exchanged heat with the circulating gas in the cooling device 11 to the radiator 13 by the liquid sending pump 14 and releasing the heat. The cooling rate of the circulating gas is controlled by the liquid feed pump 14.
This is done by adjusting the flow rate of the refrigerant sent from the refrigeration system.
FIG. 5 shows specific control.

As shown in FIG. 5, the present control can be performed by the same control as that for controlling the cooling rate of the system by adjusting the flow rate of the circulating gas. In step 31,
The temperature T in the circulation path is measured by the thermometer T1. In step 32, the amount of change in temperature in the circulation path per predetermined time ΔT
Is calculated. In step 33, the corrected refrigerant flow rate F
c ′ is calculated by equation (2), where FcO ′ is the refrigerant flow rate before correction and c ′ is the correction gain.

Fc ′ = FcO ′ + c ′ × (△ Tt− △ T) (2) In step 34, the liquid feed pump 14 is adjusted based on the calculated corrected refrigerant flow rate Fc ′. Here, the flow rate F
c ′ and Fc0 ′ are measured by a flow meter (not shown) or determined by a method such as measuring the rotation speed of the liquid feed pump 14 and referring to a flow rate map correlated with the rotation speed.

In step 35, it is determined whether or not the temperature in the circulation path has become equal to or lower than the target temperature Tt. When the temperature in the circulation path becomes equal to or lower than the target temperature Tt, step 3
Proceeding to 6, the liquid supply pump 14 is stopped. If the temperature in the circulation path is not lower than the target temperature Tt, the flow returns to step 31 to adjust the refrigerant flow again to cool the system.

Next, a reforming system (reformed gas engine system) using an engine as a power source will be described. FIG. 6 shows a reformed gas engine system. Here, the reformed gas system engine is a system in which all or part of a hydrocarbon fuel is reformed and introduced into the engine as a reformed gas mainly composed of hydrogen and carbon monoxide to operate the engine. is there. Since lean combustion can be performed by adding hydrogen to the fuel, fuel efficiency can be improved.

As shown in FIG. 6, the reformed gas engine system includes a fuel tank 1, a water tank 2, liquid feed pumps 3, 4,
27, vaporizer 5, thermometer T1, reformer 6, engine 2
8, is configured to include a cooling device and water recovery device 29, a pump 32, and a flow path switching valve (V11 to V14);
By appropriately switching the flow path switching valve, the valve V11
A return path for returning the exhaust gas to the reformer 6 is formed by the valves V11 and V14, and a gas circulation path is formed by the valves V11, V12, V13, and V14. As a result, there is no need to use a tank for storing inert gas or a large-volume combustor,
The system can be downsized.

Next, the operation of the reformed gas engine system during operation will be described. The hydrocarbon fuel is sent from the fuel tank 1 to the vaporizer 5 by the liquid feed pump 3 and the water is sent from the water tank 2 to the vaporizer 5 by the liquid feed pump 4 to be vaporized and mixed to form a mixed gas. The mixed gas is sent to the reformer 6 through the valve V11, and is reformed into a gas (reformed gas) containing hydrogen and carbon monoxide as main components.

Here, the reformer 6 generates a reformed gas by utilizing a steam reforming reaction using hydrocarbon fuel and water as raw materials. Since this reaction is an endothermic reaction, It is heated by the engine waste heat via the combined water recovery device 29. If the engine waste heat capacity is not enough,
Air is sent from an air introduction passage (not shown) to the reformer 6, and a part of the fuel undergoes a partial oxidation reaction, which is an exothermic reaction, to supplement the heat.

The reformed gas passes through the valve V12, is mixed with air and the fuel supplied by the liquid feed pump 27 without passing through the reformer 6, and is supplied to the engine 28. The exhaust gas of the engine 28 is sent to the cooling device / moisture recovery device 29 through the valve V13,
The heat exchange with the refrigerant is performed in the refrigerant 9, and the refrigerant is cooled and discharged to the outside through the valve V 14.

Next, the operation when the operation is stopped will be described with reference to the flowchart of FIG. In step 41, in response to the input of the raw material (gas) supply cut-off command to the reformer 6, in step 42, the supply of the raw material to the system is cut off by closing the vaporizer 5 side of the valve V11, and the flow path side (pump 32 side)
open. In step 43, the circulation path side (valve V13 side) of the valve V12 is opened, and the engine 28 side is closed.

In step 44, both the circulation path side of the valve V13 (the valve V12 side) and the exhaust flow path side of the engine 28 are opened. In step 45, the recirculation path side (the pump 32 side) of the valve V14 is opened, and the exhaust (external) side is closed.
By the above steps 42 to 45, a recirculation path (V14 to V11) for recirculating the exhaust gas of the engine 28 is formed, and the exhaust gas of the engine 28 and the residual reformed gas, which are inert gases, are sealed in the system. Are formed (V11 to V14). The gas in the system is circulated by the pump 32, thereby preventing a sudden rise in the temperature in the system due to the stop of the gas flow.

In step 46, the temperature T0 in the circulation path is measured by the thermometer T1. In step 47, the number of moles ng of gas present in the circulation path is calculated from the measured temperature T0 in the circulation path. In step 48, the number of moles ng calculated in step 47 is subtracted from the number of moles (target number of moles nt) for maintaining the pressure in the circulation path at about atmospheric pressure at room temperature, and the gas shortage n (= nt−ng) is obtained. Is calculated.

In step 49, an operating time te during which the engine 28 operates only with the hydrocarbon fuel is calculated in order to compensate for the gas shortage n with the exhaust gas of the engine 28. In step 50, the engine 28 is operated using only hydrocarbon fuel as fuel.
Is operated for a time te, the routine proceeds to step 51, where the engine 28 is stopped, and the exhaust passage side of the engine 28 of the valve V13 is closed.

By the above steps 46 to 51, it is possible to easily prevent the invasion of air from the outside while maintaining the pressure in the system above the atmospheric pressure (by preventing the pressure in the system from becoming negative). In this system, as in the case of the above-described fuel cell system, by adjusting the gas flow rate circulating in the system, or by adjusting the refrigerant flow rate of the cooling device and moisture recovery device 29,
The cooling rate of the system can be controlled.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a reforming system according to an embodiment of the present invention.

FIG. 2 is a flowchart showing control when the operation of the reforming system is stopped.

FIG. 3 is a flowchart showing control of a cooling rate of the reforming system.

FIG. 4 is a configuration diagram of a reforming system according to another embodiment.

FIG. 5 is a flowchart showing control of the cooling rate of the reforming system by the cooling device.

FIG. 6 is a configuration diagram of a reforming system (reformed gas engine system) according to another embodiment.

FIG. 7 is a flowchart showing control when the operation of the reformed gas engine system is stopped.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Fuel tank 2 ... Water tank 5 ... Vaporizer 6 ... Reformer 7 ... Carbon monoxide removal apparatus 8 ... Fuel cell 9 ... Water recovery apparatus 10 ... Combustor 11 ... Cooler 13 ... Radiator 28 ... Engine 29 ... Cooling Container and water recovery device

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H01M 8/04 H01M 8/04 J 8/06 8/06 GB 8/10 8/10 (72) Inventor Kazuhiko Ishiwatari Hiroshi Komatsu, Nissan Motor Co., Ltd. (72) Inventor Hiroshi Komatsu, Nissan Motor Co., Ltd. 2 Nissan Motor Co., Ltd., Nissan Motor Co., Ltd. 4G040 EA03 EA06 EB31 EB43 EB44 4G140 EA03 EA06 EB31 EB43 EB44 5H026 AA06 5H027 AA06 BA09 BA17 BA20 KK10 KK42 MM03 MM08 MM12 MM16

Claims (12)

[Claims] 1. A reforming system comprising: a reformer for reforming a hydrocarbon fuel to generate a reformed gas; and a power source for operating the reformed gas generated by the reformer as a fuel. A reforming system characterized in that the system is annularly sealed so that exhaust gas generated by the reforming system is returned to the reformer when the operation is stopped, and the gas in the sealed system is circulated by a pump. 2. The reforming system according to claim 1, wherein the pressure in the reforming system is made equal to or higher than the atmospheric pressure by controlling the amount of exhaust gas generated in the reforming system. 3. A pump for circulating the enclosed gas,
The reforming system according to claim 1, wherein the system also serves as an air pump that sends air to the reformer during operation. 4. The reforming system according to claim 1, wherein a cooling rate of the system is controlled by adjusting a flow rate of a gas circulating in the system. 5. The reforming system according to claim 1, further comprising a cooling device for cooling gas circulating in the system. 6. The reforming system according to claim 5, wherein the temperature of the gas circulating in the system is controlled by adjusting the flow rate of the refrigerant in the cooling device. 7. The reforming system according to claim 5, wherein waste heat of the cooling device is used in the reforming system. 8. The reformer according to claim 1, wherein the power source is a fuel cell, and the exhaust gas is an exhaust gas from the fuel cell or a combustion gas of the exhaust gas. system. 9. The engine according to claim 1, wherein the power source is an engine using at least one of a reformed gas and a hydrocarbon fuel used as a raw material of the reformed gas, and the exhaust gas is an exhaust gas from the engine. The reforming system according to any one of claims 1 to 7. 10. The reforming system according to claim 1, wherein the reformer performs a steam reforming reaction with a hydrocarbon fuel and water. 11. The reforming system according to claim 10, wherein waste heat from said power source is supplied to said reformer. 12. When the waste heat of the power source supplied is insufficient, the reformer compensates for the insufficient amount of heat by performing a partial oxidation reaction with a part of the hydrocarbon fuel and air. The reforming system according to claim 11, wherein