JP2010030801A - Reformer for fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reformer for a fuel cell which performs stable operation by always maintaining the inlet temperature of a reforming catalyst to be proper for a reforming reaction in a fuel cell generating apparatus using a heavy liquid fuel such as kerosene. <P>SOLUTION: The reformer for a fuel cell can be stably operated, because the temperature of a raw fuel gas at the inlet of a reforming catalyst is maintained at a temperature proper for reforming reaction or above by making the length of flow direction of a flow passage for cooling a reformed gas shorter than the length of a catalyst loading flow passage and installing a raw fuel gas preheating flow passage at the inlet part of the catalyst loading flow passage, and the inlet temperature to the reforming catalyst is always maintained at a temperature proper for reforming reaction or above even when the operation starts and the flow amount of the fuel gas is varied by installing an electric heater for preheating the raw fuel gas. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a fuel cell reformer capable of reforming a fuel having 5 to 15 carbon atoms such as kerosene as raw fuel.

A fuel cell reformer is a device that generates hydrogen-rich gas from a hydrocarbon-based fuel by a chemical reaction such as steam reforming, partial reforming, or autothermal using a catalyst, and is used for supplying hydrogen to a fuel cell power plant. Yes.

In recent years, solid polymer fuel cell power generators with a power output of several hundred watts to 10 kW have been developed for home and small-scale business use, and fuel cell reformers are also highly efficient, small and light. For the purpose, a heat exchanger, a CO converter (carbon monoxide converter), a CO selective oxidizer (carbon monoxide selective oxidizer) and the like that have been integrated or combined have been proposed (for example, Patent Document 1). , See Patent Document 2).

These reformers for fuel cells use gas fuels such as city gas mainly composed of methane and LP gas mainly composed of propane, which are easy to reform, and gas fuel has low energy density per volume. Because of its large volume for storage, development of a fuel cell reformer that can use liquid fuel such as kerosene, which has high energy density and is easy to store and handle, is desired in areas where pipelines are undeveloped. .
Re-publication WO2002 / 025762 JP 2002-187705 A

  The reforming of liquid fuel from 5 to 15 carbon atoms to hydrogen gas has harsher reaction conditions compared to city gas and LP gas fuels having 1 to 4 carbon atoms, especially from 10 to 10 carbon atoms. When 15 kerosene is used as fuel, under conditions where the reforming catalyst inlet temperature is 450 ° C. or lower, carbon deposition on the catalyst or reduction in conversion rate to hydrogen gas occurs, and unreacted liquefied components flow out from the reforming catalyst outlet. However, there has been a problem of deteriorating the downstream CO conversion catalyst and the fuel cell body.

The present invention can use liquid fuel such as kerosene that is easy to store and handle, can reduce the amount of carbon deposited on the catalyst, can increase the conversion rate to hydrogen fuel, and the unreacted liquefied component can be used as a reforming catalyst. An object of the present invention is to provide a fuel cell reformer capable of preventing outflow from an outlet and capable of performing stable operation.

In order to achieve the above object, the invention corresponding to claim 1 forms a combustion space for combusting the fuel of the combustor in a housing provided with a combustor for combusting fuel at the center, An annular catalyst filling flow path is formed concentrically on the outer peripheral side of the combustion space, and an annular reformed fuel cooling flow path is formed concentrically on the outer peripheral side of the catalyst filling flow path. In the fuel cell reformer in which a raw fuel preheater for preheating the raw fuel concentrically is formed on the outer peripheral side of the flow path, the length in the flow direction of the raw fuel in the reformed fuel cooling flow path is set. The fuel cell reformer is characterized in that it is shorter than the length of the raw fuel in the flow direction of the catalyst.

In order to achieve the above object, an invention corresponding to claim 5 forms a combustion space for combusting the fuel of the combustor in a housing provided with a combustor for combusting fuel at the center, A non-catalyst filling passage is formed on the outer peripheral side of the combustion space, a non-reforming fuel cooling passage is formed on the outer peripheral side of the catalyst filling passage, and on the outer peripheral side of the reforming fuel cooling passage. In a fuel cell reformer in which a raw fuel preheater for preheating non-raw fuel is formed, a length of the raw fuel in a flow direction of the raw fuel in the reformed fuel cooling flow path is set in the catalyst filling flow path. The fuel cell reformer is shorter than a length in a flow direction of the raw fuel.

  According to the present invention, liquid fuel such as kerosene that can be easily stored and handled can be used, carbon deposited on the catalyst can be reduced, the conversion rate to hydrogen fuel can be increased, and unreacted liquefied components can be improved. It is possible to provide a fuel cell reformer that can prevent outflow from the catalyst outlet and can perform stable operation.

  Hereinafter, an embodiment of a reformer for a fuel cell according to the present invention will be described with reference to the drawings.

(First embodiment)
The fuel cell reformer of FIG. 1 roughly burns the burner fuel of the combustor 1 with burner air in the center of the inside of the housing 2 provided with the combustor 1 that burns fuel at the center of the upper wall surface. A combustion space 23 is formed, and an annular catalyst filling flow path 3 is formed concentrically on the outer peripheral side of the combustion space 23, and a concentric annular reforming fuel cooling flow is formed on the outer peripheral side of the catalyst filling flow path 3 A path 4 is formed, and an annular raw fuel preheater 5 for preheating the raw fuel concentrically on the outer peripheral side of the reformed fuel cooling flow path 4 is formed. The length in the flow direction of the raw fuel is made shorter than the length in the flow direction of the raw fuel in the catalyst filling channel 3. As a result, fuel such as kerosene having 5 to 15 carbon atoms, such as raw fuel gas, can be reformed as raw fuel.

The housing 2 includes a bottomed cylindrical portion and a closed portion that closes the opening of the bottomed cylindrical portion, and a heat insulating material 24 is provided on the inner wall surface of the bottomed cylindrical portion and the closed portion. The combustion space 23 inside the housing 2 is
The cylindrical member 31 is constituted by a lid member 25 and a bottom member 26 joined to both ends of the cylindrical member 31, and the combustor 1 passes through the lid member 25 and the upper wall portion (closed portion) of the housing 2. The steam generator 9 is provided so as to pass through the bottom member 26 and the lower wall portion (bottom portion) of the housing 2.

The steam generator 9 has a combustion gas outlet 101 for discharging the combustion gas generated in the combustor 1 to the outside of the casing, and is a cylindrical combustion gas discharge pipe provided so as to penetrate the bottom member 26 and the casing 2. 91
A steam pipe 93 that is spirally disposed on the outer peripheral side of the combustion gas discharge pipe 91, discharges water introduced from outside as steam and discharges it to the outside, and the outer peripheral side of the steam pipe 93 and the combustion gas discharge pipe 91. The center plug 92 is provided so as to surround the upper space. In this case, the combustion gas combusted by the combustor 1 passes through the radiant heat transfer section 21 existing on the upper side (combustor 1 side) in the combustion space 23 and passes through the lower center plug 92 in the combustion space 23. After passing through the convection heat transfer section 22 existing at a position where the outer peripheral side and the cylindrical member 31 face each other, the gas is discharged outside from the combustion gas discharge pipe 91 through the space existing on the outer circumference of the water vapor pipe inside the center plug 92. ing.

  The catalyst filling flow path 3 is disposed with a space from the outer peripheral surface of the cylindrical member 31, and a cylindrical flow path constituting member 32 constituting a catalyst filling path that is short in the axial direction length of the cylindrical member 31; The upper and lower ends of the flow path component 32 so that the space between the flow path component 32 and the cylindrical member 31 can be filled with the reforming catalyst 33 and the raw fuel gas flows inside the reforming catalyst 33. And partition members 34 and 35 fixed to the outer peripheral surface of the cylindrical member 31.

  In the above configuration, in the space where the outer peripheral surface of the flow path component 32 on the outer peripheral side of the catalyst filling flow path 3 and the inner wall surface of the upper half of the housing 2 face each other, the reformed fuel cooling flow path 4 and the raw fuel In order to form the preheater 5 and the raw fuel preheater 5, a cylindrical partition wall 41 that hangs vertically is provided inside the upper wall of the housing 2. In this case, the space between the inner peripheral surface of the partition wall 41 and the outer peripheral surface of the flow path component 32 of the catalyst filling flow path 3 is called the reformed fuel cooling flow path 4, and the raw fuel in the reformed fuel cooling flow path 4 The length in the flow direction refers to a portion in which the axial length of the inner peripheral surface of the partition wall 41 and the axial length of the outer peripheral surface of the flow path constituting member 32 of the catalyst filling flow path 3 opposed thereto are matched. .

  The raw fuel preheater 5 supplies a raw fuel preheating pipe 51 spirally disposed in a space between the outer peripheral side of the partition wall 41 and the housing 2 and a raw fuel gas connected to one end of the raw fuel preheating pipe 51. In order to heat the inside of the connecting pipe 7, the raw fuel inlet pipe 6 penetrating the wall surface of the housing 2, the connecting pipe 7 connecting the other end of the raw fuel preheating pipe 51 and one end of the catalyst filling flow path are connected. It consists of the electric heater 10 provided in the outer peripheral surface of the connecting pipe 7, or the inside of the connecting pipe 7.

  It is the housing | casing 2 which consists of a bottomed cylindrical part and the obstruction | occlusion part which obstruct | occludes the opening part of a bottomed cylindrical part, Comprising: The heat insulating material 24 is provided in the inner wall face of the housing | casing 2, and it has in this internal space. Both end portions on the inner side of the catalyst filling flow path 3 are closed by a lid member 25 and a bottom member 26 to form a combustion space 23. A reforming catalyst 33 is filled between the cylindrical inner partition wall 31 and the cylindrical outer partition wall 32 of the catalyst filling channel 3. The reforming catalyst 33 is held by partitions 34 and 35 so that the raw fuel gas can flow through the reforming catalyst 33.

A concentric reforming fuel cooling channel 4 is formed on the outer peripheral side of the outer partition wall 32 of the catalyst filling channel 3, and the length of the reforming fuel cooling channel 4 in the axial direction is the reforming catalyst. The length in the axial direction of 33, that is, the length of the flow path through which the raw fuel gas flows is, for example, 60% shorter.

The raw fuel preheater 4 installed on the outer peripheral side of the reformed fuel cooling channel 4 includes a preheater cooling channel 52 through which the reformed gas from the reformed gas cooling channel 4 flows, and the preheater cooling flow. The raw fuel preheating pipe 51 is arranged inside the passage 52 so as to be spirally continuous. Fuel reformed reformed fuel, that is, hydrogen gas, flowing through the reformed gas cooling passage 52 of the raw fuel preheater 5 can be taken out from the reformed gas outlet pipe 8 connected to the reformed gas cooling passage 52. One end of the raw fuel preheating pipe 51 of the raw fuel preheater 5 connected to the raw fuel inlet pipe 6 for supplying raw fuel gas from the outside of the reformer is connected to the other end of the raw fuel preheating pipe 51. The one end of the connecting pipe 7 is connected, and the other end of the connecting pipe 7 is led to the lower end of the catalyst filling flow path 3. An annular heating means such as an electric heater 10 is installed inside or on the outer peripheral surface of the connecting pipe 7.

In the combustion space 23, a steam generator 9 including a partition wall 91, a cylindrical center plug 92, and a steam pipe 93 is disposed. Specifically, one end of a partition wall 91 is joined to the bottom member 26 so that the combustion gas in the combustion space 23 can be taken out of the reformer through the partition wall 91. A center plug 92 is disposed on the outer peripheral side of the partition wall 91 so as to form a predetermined space therebetween, and a steam pipe 93 is spirally disposed in the center plug 92. Water is introduced from one end, and water vapor generated in the water vapor pipe 93 is discharged to the outside.

Next, the operation of the fuel cell reformer having the above configuration will be described. The raw fuel gas mixed with vaporized liquid fuel and water vapor at 100 ° C. to 150 ° C. is supplied to the inlet side of the catalyst filling flow path 3 through the raw fuel inlet pipe 6, the raw fuel preheating pipe 51 and the connecting pipe 7 in order. This passes through the gap in the reforming catalyst 33 of the catalyst filling flow path 3, and the raw fuel gas flows from the outlet side of the catalyst filling flow path 3 to the reformed fuel cooling flow path 4 and the preheater cooling flow path. 52 and the reformed gas outlet pipe 8 are sequentially discharged to the outside of the housing 2.

  In this way, the raw fuel gas is supplied to the raw fuel preheating pipe 51 of the raw fuel preheater 5, receives heat energy from the preheater cooling flow path 52, and is heated to 450 ° C. or higher. And flows into the catalyst-filled flow path 3. The raw fuel gas that has flowed into the catalyst filling flow path 3 receives heat energy from the convection heat transfer section 22 in the combustion space, and the temperature is raised to, for example, about 500 ° C., and steam reforming is performed by the action of the reforming catalyst 33. As a result, a part of the raw fuel gas is reformed into hydrogen, carbon monoxide, and carbon dioxide to become a mixed gas with a high hydrogen concentration.

  Further, when receiving heat energy from the radiant heat transfer portion 21 of the combustion gas and the reformed fuel cooling flow path 4, a similar steam reforming reaction is caused to reform into a reformed gas having a predetermined hydrogen concentration. The temperature of the mixed gas at this time is raised to about 700 ° C., for example.

  Then, the reformed gas exiting the catalyst filling flow path 3 flows into the reformed fuel cooling flow path 4 and gives thermal energy to the catalyst filling flow path 3 so that the temperature is lowered to 500 ° C., for example. The reformed gas exiting the reformed fuel cooling flow path 4 flows into the preheater cooling flow path 52 of the fuel preheater 5 and gives thermal energy to the raw fuel preheat pipe 51 to decrease the temperature to 280 ° C., for example. It is discharged from the reformed gas outlet pipe 8 and supplied to a CO converter and a CO selective oxidizer (not shown).

  On the other hand, the burner fuel and burner air are burned in the combustor (burner) 1 to become a combustion gas of about 1200 ° C. to 1300 ° C., flow into the radiant heat transfer section 21 and give thermal energy to the catalyst filling flow path 3 to increase the temperature. For example, the temperature drops to about 800 ° C. and flows into the convection heat transfer section 22. Further, while the combustion gas flows through the convection heat transfer section 22, the temperature is reduced to, for example, 450 ° C. by giving thermal energy to the catalyst filling channel 3. Thereafter, the combustion gas flows into the center plug 92, gives heat energy to the steam pipe 93 constituted by a spiral pipe, is cooled to about 100 ° C., and is supplied from the combustion gas outlet 101 to a heat recovery heat exchanger (not shown). The Moisture flowing into the steam generator 9 receives heat energy from the combustion gas in the center plug 92, and all or part of it evaporates into water vapor, which is used as water vapor for the raw fuel gas.

  The raw fuel gas flowing into the catalyst filling channel 3 is heated by the raw fuel preheater 5, and the low temperature raw fuel gas from the raw fuel gas inlet pipe 6 is heated at a high temperature from the reforming and cooling channel 4. Heat is obtained by obtaining heat energy from gas. When the inlet temperature to the reforming catalyst 33 is set to 450 ° C. or higher, the outlet temperature of the raw fuel gas of the raw fuel preheater 5 needs to be heated to 450 ° C. or higher, and the reformed fuel cooling that is a heat source for heating is used. The outlet temperature of the reformed gas in the working channel 4 also needs to be at least 450 ° C. or higher.

  The reformed gas outlet temperature of the reformed fuel cooling channel 4 varies depending on the contact area between the reformed gas cooling channel 4 and the catalyst charging channel 3, and the reformed fuel cooling channel 4 and the catalyst charging channel are changed. 3 have the same contact area, the heat exchange from the reformed gas flowing in the reformed fuel cooling flow path 4 to the mixed gas flowing in the catalyst-filled flow path 3 becomes excessive. The outlet temperature of the reformed gas in the quality gas cooling channel 4 becomes 450 ° C. or lower.

  In the present embodiment, the length of the reformed fuel cooling flow path 4 in the flow direction is made shorter than the length of the catalyst filling flow path 3, and the heat exchange amount from the reformed gas to the mixed gas is appropriately set. The reformed gas outlet temperature of the quality fuel cooling flow path 4 is set to about 500 ° C., the raw fuel gas outlet temperature of the raw fuel preheater 5 and the inlet temperature to the reforming catalyst 33 are set to 450 ° C. or higher.

  Further, when the raw fuel gas outlet temperature of the raw fuel preheater 5 becomes 450 ° C. or lower at the time of starting or changing the flow rate of the raw fuel gas, the raw fuel gas is provided by the electric heater 10 disposed in the communication pipe 7. Is heated to 450 ° C. or higher.

  According to the embodiment having the above configuration, liquid fuel such as kerosene that can be easily stored and handled can be used, carbon deposited on the catalyst can be reduced, conversion rate to hydrogen fuel can be increased, and An unreacted liquefied component can be prevented from flowing out from the reforming catalyst outlet, and a fuel cell reformer capable of performing stable operation can be provided.

  Incidentally, the heat exchange amount from the reformed gas to the mixed gas can be appropriately set by making the length in the flow direction of the reformed fuel cooling channel 4 shorter than the length of the catalyst-filled channel 3. In addition, the inlet temperature of the raw fuel gas from the raw fuel preheater 5 to the reforming catalyst 33 can be set to 450 ° C. or more, and an electric heater 10 is installed in the connecting pipe 7 to add a raw fuel gas preheating function. In addition, since the inlet temperature to the reforming catalyst 33 can always be 450 ° C. or higher even when starting up or when the flow rate of the raw fuel gas is changed, the inlet temperature to the reforming catalyst 33 suitable for the reforming reaction is always maintained and stable. It becomes possible to drive.

(Second Embodiment)
The second embodiment will be specifically described with reference to FIG. In FIG. 2, the same members as those in FIG.

  In the second embodiment, a raw fuel (raw fuel gas) preheating flow path 102 is installed at the inlet of the catalyst filling flow path 3. The raw fuel preheating channel 102 is filled with a particle or fibrous heat transfer promoting material 103 made of ceramic or metal. Further, a porous partition plate 104 that can be fixed or floated is installed between the catalyst filling channel 3 and the raw fuel preheating channel 102. In addition, an electric heater 105 is installed in a partition wall outside the raw fuel preheating channel 102. The other points are the same as in FIG.

  The operation of the present embodiment having the above-described configuration is as follows. The raw fuel gas emitted from the raw fuel preheater 5 passes through the connecting pipe 7 and flows into the raw fuel preheat flow path 102. Even if the temperature of the raw fuel gas flowing into the raw fuel preheating flow path 102 is less than 450 ° C., it flows from the convection heat transfer section 22 of the combustion gas while flowing through the raw fuel preheating flow path 102 filled with the heat transfer promoting material 103. In response to the thermal energy, it is heated to 450 ° C. or higher and flows into the catalyst-filled flow path 3. Further, the reforming catalyst 33 in the catalyst filling flow path 3 and the heat transfer promoting material 103 in the raw fuel preheating flow path 102 are not mixed by the porous partition plate 104.

  Further, when the outlet temperature of the raw fuel gas in the raw fuel preheating channel 102 becomes 450 ° C. or lower at the time of starting or changing the flow rate of the raw fuel gas, the raw fuel gas is disposed in the partition wall outside the raw fuel preheating channel 102. The raw fuel gas is heated to 450 ° C. or higher by the electric heater 105.

  The effects of the present embodiment having the above-described configuration are as follows.

Since the raw fuel preheating flow path 102 is installed at the inlet of the catalyst filling flow path 3 and the raw fuel gas preheating function is added, the reforming catalyst is provided even if the raw fuel gas outlet temperature of the raw fuel preheater 5 is less than 450 ° C. The inlet temperature of 33 can be set to 450 ° C. or higher.

  Since heat transfer from the combustion gas to the raw fuel gas is made good by the heat transfer promoting member 103 inside the raw fuel preheating channel 102, the raw fuel gas can be efficiently heated.

  The porous partition plate 104 prevents the raw fuel and the reformed fuel from being mixed in the reforming catalyst 33 and the raw fuel preheating channel 102. It is possible to prevent a steam reforming reaction at 450 ° C. or lower from occurring inside.

  Furthermore, since the electric heater 105 is installed in the partition wall outside the raw fuel preheating flow path 102 and the preheating function of the raw fuel gas is added, the inlet temperature to the reforming catalyst 33 at the time of starting or when the flow rate of the raw fuel gas is changed. Can always be maintained at 450 ° C. or higher.

(Modification)
In the above-described embodiment, the catalyst filling flow path, the reformed fuel cooling flow path, and the raw fuel preheater are each in an annular shape in the combustion space inside the casing, and these are described as being concentrically arranged. In addition, the catalyst filling flow path, the reformed fuel cooling flow path, and the raw fuel preheater are each non-annular, for example, plate-shaped, and are arranged in order in one direction in the combustion space inside the casing. But you can.

1 is a longitudinal sectional view showing a first embodiment of a reformer for a fuel cell according to the present invention. The longitudinal cross-sectional view which shows 2nd Embodiment of the reformer for fuel cells which concerns on this invention.

Explanation of symbols

    DESCRIPTION OF SYMBOLS 1 ... Combustor, 2 ... Housing, 3 ... Catalyst filling flow path, 4 ... Reformed fuel cooling flow path, 5 ... Raw fuel preheater, 6 ... Raw fuel inlet pipe, 7 ... Communication pipe, 8 ... Reforming Gas outlet pipe, 9 ... Steam generator, 10 ... Electric heater, 21 ... Radiation heat transfer section, 22 ... Convection heat transfer section, 23 ... Combustion space, 24 ... Insulating material, 25 ... Cover member, 26 ... Bottom member, 31 DESCRIPTION OF SYMBOLS ... Cylindrical member, 32 ... Flow path component, 33 ... Reforming catalyst, 34, 35 ... Partition member, 41 ... Partition, 51 ... Raw fuel preheating pipe, 52 ... Preheater cooling flow path, 91 ... Combustion gas discharge pipe, 92 ... Center plug, 93 ... Steam pipe, 101 ... Combustion gas outlet, 102 ... Raw fuel preheating flow path, 103 ... Heat transfer accelerator, 104 ... Porous partition plate, 105 ... Electric heater.

Claims (8)

A combustion space for combusting the fuel of the combustor is formed inside a housing having a combustor that combusts fuel in the center, and a concentric annular catalyst filling channel is formed on the outer peripheral side of the combustion space. Forming a concentric annular reformed fuel cooling channel on the outer peripheral side of the catalyst filling channel, and preheating the raw fuel concentrically on the outer peripheral side of the reformed fuel cooling channel. In a fuel cell reformer that forms an annular raw fuel preheater,
A reformer for a fuel cell, wherein a length in the flow direction of the raw fuel in the reformed fuel cooling flow path is shorter than a length in the flow direction of the raw fuel in the catalyst filling flow path. The reformer for a fuel cell according to claim 1, further comprising an annular reformed fuel preheating channel filled with a heat transfer promoting material at an inlet portion of the raw fuel in the catalyst charging channel.   3. The reformer for a fuel cell according to claim 2, further comprising an annular porous partition member that can be fixed or floating between the catalyst filling channel and the reformed fuel preheating channel.   The heating means is provided in the pipe line or the reformed fuel preheating flow path through which the raw fuel flows from the raw fuel preheater to the catalyst filling flow path. Fuel cell reformer. A combustion space for combusting the fuel of the combustor is formed inside a housing having a combustor that burns fuel in the center, and a non-circular catalyst filling channel is formed on the outer peripheral side of the combustion space. A raw fuel preheater for forming a non-annular reformed fuel cooling channel on the outer peripheral side of the catalyst filling channel and preheating the non-annular raw fuel on the outer peripheral side of the reformed fuel cooling channel In the fuel cell reformer formed with
A reformer for a fuel cell, wherein a length in the flow direction of the raw fuel in the reformed fuel cooling flow path is shorter than a length in the flow direction of the raw fuel in the catalyst filling flow path. 6. The reformer for a fuel cell according to claim 5, further comprising a non-annular reformed fuel preheating channel filled with a heat transfer promoting material at an inlet portion of the raw fuel in the catalyst charging channel.   The reformer for a fuel cell according to claim 6, further comprising a non-circular porous partition member that can be fixed or floating between the catalyst filling channel and the reformed fuel preheating channel.   The heating means is provided in the pipe line through which the raw fuel flows from the raw fuel preheater to the catalyst filling flow path or the reformed fuel preheating flow path, according to any one of claims 5 to 7. Fuel cell reformer.

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