JPH11106204A - Hydrogen production apparatus and hydrogen production process - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydrogen production apparatus capable of generating steam and heating a fuel without using a boiler or a heat-exchanger or complicating the apparatus construction. SOLUTION: A raw fuel mixture composed of a raw fuel, air and water is heated by the sensible heat of partial oxidization reaction in the course of flowing through an end (a spiral part in the Figure) depressed in the reforming catalyst layer 100 of a pipe L3 and introduced into the reforming catalyst layer 100 together with the produced steam. The apparatus can dispense with additional heating means to simplify the apparatus construction since the heating of the raw fuel and the generation of steam are carried out by effectively utilizing the sensible heat in the reaction system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved technology of a hydrogen producing apparatus for producing a hydrogen-rich reformed gas by reforming a fuel such as a hydrocarbon using steam.

[0002]

2. Description of the Related Art In a hydrogen production apparatus for supplying hydrogen to a fuel cell or the like, a hydrocarbon-based raw fuel such as natural gas, methanol, and naphtha is mixed with steam to form a hydrogen-rich gas with a reforming catalyst. A so-called steam reforming method for reforming is employed. In the case of butane as an example, this steam reforming is represented by the following reaction formula 1 and is usually from 600 ° C. to 800 ° C.
It is performed at a high temperature of about ° C.

[0003]

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[0004] The reformed gas generated here contains carbon monoxide to some extent (several ten percent). Since carbon monoxide CO is a factor that lowers the catalytic activity of the electrode, it is necessary to prevent this. Through a CO converter equipped with a shift catalyst,
In many cases, carbon monoxide CO in the reformed gas is subjected to a shift reaction to carbon dioxide CO ₂ by the reaction shown below, and then supplied to the fuel cell.

[0005]

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[0006] Such a steam reforming apparatus is sometimes used at home or outdoors, and in such a case, the apparatus design is required to be as compact as possible in terms of arrangement space and transportation convenience. As an example of a conventional relatively compact steam reformer, as disclosed in JP-A-2-264903 and JP-A-5-186201, a reforming reaction catalyst is provided in a double cylindrical tube. There is known a method in which raw fuel and steam are fed into a reaction tank while heating the reaction tank filled with the gas with a burner to reform the reaction tank.

Further, as disclosed in Japanese Patent Application Laid-Open No. Hei 7-335238, raw fuel is first mixed with air and partially oxidized using a partial oxidation catalyst. A device has been developed that mixes with steam and reforming with a reforming catalyst. In this device, the heat generated by the partial oxidation reaction is transferred to the reforming catalyst and used for the reforming reaction. I have.

[0008]

However, such a hydrogen production system using the steam reforming system is operated while receiving the supply of steam, and therefore cannot be operated in the field without a heat source such as a boiler. . If a steam supply source such as a boiler is newly provided, the apparatus can be operated, but there is a problem that the apparatus configuration becomes complicated.

In addition, when the raw fuel is supplied after being preheated, it is necessary to separately provide a heating means such as a heat exchanger outside the reactor. Become. Accordingly, a first object of the present invention is to provide a hydrogen production apparatus capable of generating steam and heating fuel without complicating the apparatus configuration and without a boiler or a heat exchanger. I do.

Further, when the hydrogen production apparatus is used in a polymer electrolyte fuel cell system or the like where the influence of carbon monoxide remaining in the reformed gas is large, in order to lower the carbon monoxide CO concentration, Usually, in addition to the CO transformer, C
An O remover is provided to reduce the carbon monoxide CO concentration in multiple stages. However, if there are many reactors, the monitoring burden on the operator must be increased, and the reaction must be performed accordingly. The configuration of the hydrogen production apparatus becomes complicated.

Therefore, a second object of the present invention is to provide a method for producing hydrogen which can sufficiently reduce the concentration of carbon monoxide CO even with a small number of reactors. In addition, after the hydrogen production equipment heats the reaction tank to a certain temperature,
A general operation procedure is to enter a steady operation. As a method for raising the temperature, a so-called external heating method in which a combustion gas of a burner is forcibly circulated outside a reaction tank is a normal method.

It is desirable that the time for raising the temperature be as short as possible, and that the temperature of the inside of the reaction catalyst layer be raised so that the temperature distribution becomes as uniform as possible. Japanese Patent Laid-Open No. 6-2 is a technique for responding to such a demand.
Japanese Patent Application Laid-Open No. 19705 discloses that, in the case of the external heating, for example, a combustion burner having a large number of nozzles is arranged around a catalyst layer so that the heat transfer rate of heat is as large as possible. Although a technique of increasing the area of the surface and the reaction tank facing each other has been disclosed, in this technique, the catalyst layer includes the passage space through which the combustion gas flows because the burner is opposed to the peripheral surface. It becomes large.

Therefore, a third object of the present invention is to provide a compact hydrogen production apparatus capable of rapidly raising the temperature without increasing the size of the apparatus.

[0014]

In order to achieve the first object, the present invention provides a hydrogen production apparatus, comprising: a partial oxidation section having a partial oxidation reaction layer for partially oxidizing fuel;
A reforming section provided with a steam reforming catalyst layer for generating a hydrogen-rich reformed gas by performing a steam reforming reaction on the fuel by receiving a supply of steam, heating the fuel, and subjecting the heated fuel to the partial oxidation; A fuel supply unit for supplying the steam to the reforming unit, wherein at least one of the fuel supply unit and the steam supply unit serves as a heat source. It is characterized by using heat generated by the oxidation reaction.

[0015] In addition, the steam reforming reaction is performed by receiving the supply of steam to generate a hydrogen-rich reformed gas by performing a steam reforming reaction on the fuel and simultaneously performing a partial oxidation reaction for partially oxidizing the fuel using oxygen. A reforming unit provided with a catalyst layer, a fuel supply unit for heating the fuel and supplying the heated fuel to the steam reforming unit, and a steam for generating the steam and supplying the steam to the reforming unit A steam supply means, wherein at least one of the fuel supply means and the steam supply means uses heat generated by a partial oxidation reaction as a heat source.

[0016] Accordingly, even if a heating device such as a boiler or a heat exchanger for heating fuel or generating steam is not provided,
Since heating and generation of steam are performed by effectively using the sensible heat of the partial oxidation reaction, which is an exothermic reaction, heating of fuel and generation of steam can be performed with a simple configuration without complicating the device configuration. it can. Further, in order to achieve the second object, the hydrogen production method of the present invention provides a partial oxidation reaction step in which a fuel is reacted with oxygen to perform a partial oxidation reaction, and a combustion heat generated by the partial oxidation reaction. A reformed gas generating step of generating a hydrogen-rich reformed gas by performing a steam reforming reaction on the fuel at a temperature of not more than 0 ° C., and reacting carbon monoxide in the reformed gas with residual oxygen in the reformed gas. Selective oxidation step of selectively oxidizing.

According to this hydrogen production method, since the reformed gas is generated at a low temperature of 500 ° C. or less, there is no need to provide a CO converter, and oxygen supply means for the selective oxidation reaction becomes unnecessary. Sufficient carbon monoxide C with less equipment
O concentration can be reduced. Further, in order to achieve the third object, there is provided a hydrogen production apparatus provided with a reforming catalyst for producing a hydrogen-rich reformed gas by performing a steam reforming reaction on the fuel, wherein the combustion gas is burned by burning the fuel. A fuel combustion section to be generated, wherein the reforming catalyst is communicated with the fuel combustion section by a combustion gas passage, and the combustion gas is introduced into the reforming catalyst from the combustion gas passage, and the reforming catalyst is heated. It is characterized by that.

As described above, since the combustion gas is introduced into the reforming catalyst and the reforming catalyst is directly heated, as described above, the apparatus is quickly and uniformly raised from the inside of the catalyst layer without increasing the size of the apparatus. Can be warmed.

[0019]

[Embodiment 1]

[Overall Configuration of Hydrogen Production Apparatus] FIG. 1 is a perspective view showing a main configuration of a hydrogen production apparatus according to one embodiment of the present invention, and FIG. 2 is a fuel cell system using the hydrogen production apparatus. FIG. 2 is a block diagram (including a sectional view of a main part of the hydrogen production apparatus) illustrating the configuration of FIG.

The hydrogen production apparatus is composed of a hydrogen production apparatus main body 1
A control unit 40 for controlling the supply amounts of raw fuel, air and water in accordance with the amount of load current of the fuel cell 50; a pump P1 for supplying raw fuel; air fans F1 and F2; A raw fuel / air mixing unit 15 where mixing is performed, and a water pump P
2, various measuring meters M1, M2, M3, a burner B, and piping systems L1 to L6.

In the claims, the term "raw fuel" used in each embodiment is described as "fuel", but this is used differently for convenience and has a substantial meaning. It is not different. The hydrogen production apparatus main body 1 is roughly oxidized using a mixture of raw fuel (for example, butane), air and steam (hereinafter, referred to as “raw fuel mixture”) (typically represented by Chemical Formula 3 below). (Reaction between raw fuel and oxygen) together with steam reforming to produce a hydrogen-rich reformed gas, and convert carbon monoxide CO in the reformed gas into carbon dioxide CO ₂ ,
It comprises a shift reaction tank 20 for reducing the concentration of carbon monoxide CO in the reformed gas, and a heating tank 30 for raising the temperature of the reforming reaction tank 10 to a predetermined temperature when the apparatus is started.

[0022]

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In the reforming reaction tank 10, a reforming catalyst layer 100 is disposed substantially at the center of a cylindrical container 101 having a bottom and a bottom.
1 is a columnar first buffer layer 110 for uniformly distributing the raw fuel mixture throughout the reforming catalyst layer 100.
However, in the upper container 101 of the reforming catalyst layer 100, a columnar second buffer layer 120 for collecting the reformed gas having passed through the reforming catalyst layer 100 is secured. The second buffer layer 1
The space volume of 20 is designed to be larger than the space volume of the first buffer layer 110, thereby improving the reforming gas cooling efficiency described later. Further, a temperature sensor Se1 is provided in the center of the reforming catalyst layer 100.

The reforming catalyst layer 100 comprises the container 101
A pair of mesh members 100a are arranged near the upper and lower ends of the inside, and catalyst particles 100b are filled between the mesh members 100a. As the catalyst particles 100b used here, for example, a known catalyst in which an active site is formed by sintering Rh, Ru, Ni, or the like on a ceramic particle carrier such as silica or γ-AlO ₂ may be used. it can.

The shift reaction tank 20 is a cylindrical body provided around the reforming reaction tank 10.
To reduce the concentration of carbon monoxide CO in the reformed gas generated in step (1). A shift catalyst layer 200 that performs a shift reaction is disposed in the center. The shift catalyst layer 2
00, a pair of mesh members 200a are arranged near the upper and lower ends of the cylindrical body, similarly to the reforming catalyst layer 100, and the catalyst particles 200b
Is formed by filling. It is sufficient to use a conventional catalyst as the shift catalyst.

A third buffer layer 210 for uniformly distributing the reformed gas recovered by the second buffer layer 120 to the entire shift catalyst layer 200 is formed above the shift catalyst layer 200. Below the catalyst layer 200, a fourth buffer layer 220 for recovering reformed gas in which carbon monoxide CO has been reduced by a shift reaction is secured. In addition, a heat insulating member (not shown) is provided on a wall surface of the shift reaction tank 20 near the reforming reaction tank 10 so that heat of the reforming reaction tank 10 is not easily transmitted.

The heating tank 30 is provided with the shift reaction tank 20.
And a bottomless cylindrical body 301 having an outer diameter substantially equal to the inner circumference of the shift reaction tank 20 inserted into the inner peripheral side of the shift reaction tank 20, and a burner B disposed below the cylindrical body 301. .
Then, the reforming reaction tank 10 is in a state of being inserted into the heating tank 30, and in a space 300 portion surrounded by the outer peripheral wall surface of the reforming reaction tank 10 and the inner peripheral wall surface of the cylindrical body 301. The combustion gas generated by the burner B flows. The combustion gas introduced into the space 300 is supplied to the reforming reaction tank 1
The heat is released to the 0 and shift reaction tanks 20 and is supplied to heating from outside the tanks and exhausted to the outside air.

Next, the piping system and various measuring instruments will be described. In the raw fuel / air mixing section 15, a pipe L1 through which raw fuel flows from a raw fuel supply pump P1 and an air fan F
The pipe L2 through which the air from 1 flows is connected. A raw fuel flow meter M1 for measuring the flow rate of the raw fuel is provided in the pipe L1.
An air flow meter M2 for measuring the air flow rate is attached to the pipe L2. During operation, each flow rate is measured, and the measurement data is transmitted to the control unit 40.
The driving force of the raw fuel supply pump P1 and the air fan F1 is controlled in accordance with the instruction, and the air-fuel ratio (weight ratio of air to raw fuel) is set to a predetermined value.

The raw fuel / air mixing section 15 is connected to a pipe L3.
Is connected to the reforming reaction tank 10. The piping L3
Is inserted from the upper part of the reforming reaction tank 10, penetrates the second buffer layer 120 and the reforming catalyst layer 100, and an end (exit) thereof faces the first buffer layer 110. As a result, the raw fuel mixture in the pipe L3 and the reaction gas in the reforming catalyst layer 100 and the second buffer layer 120 flow countercurrently.

In the present embodiment, the portion of the pipe L3 inserted into the inside of the reforming reaction tank 10 is formed into a spiral with a predetermined pitch, and the heat exchange area is designed to be large to improve the heat exchange efficiency. Is being planned. The pipe L4 is a pipe for supplying water, and is provided so as to spirally turn above the burner B and then run vertically in the space 300. When the burner B burns, the pipe L4 flows through the pipe L4. The flowing water is vaporized to generate steam.

The pipe L3 joins the pipe L4. Water is further mixed into the mixture of the raw fuel and air to be supplied to the reforming reaction tank 10 as the raw fuel mixture. A water flow meter M3 is attached to the pipe L4, the flow rate is measured during operation, and the measurement data is transmitted to the control unit 40,
The liquid sending power of the water pump P2 is controlled by the control unit 40.

The reforming reaction tank 10 and the shift reaction tank 2
0 indicates the upper part thereof, that is, the second buffer layer 120 and the third
A plurality of connection pipes L at positions where the connection pipes communicate with the buffer layer 210.
They are linked by 5 ... A pipe L6 is connected to a lower portion of the shift reaction tank 20, and a reformed gas having a reduced carbon monoxide CO concentration is led out to the fuel cell 50.

The control unit 40 includes a CPU (not shown) that controls the entire apparatus, and a raw fuel supply pump P 1,
A ROM containing a program for adjusting the driving force of the water pump P2 and the fans F1 and F2, and an RA for temporarily storing flow rate data, temperature data, and load current values of the fuel cell.
M, raw fuel supply pump P1, water pump P2 and fan F
1, a drive circuit for sending a drive signal to F2, etc., and each flow meter M1, M
2, M3 and an extended I / O connected to the temperature sensor Se1.

[Regarding Operation of Hydrogen Production Apparatus] (1) At the time of starting the apparatus At the time of starting the apparatus, the temperature is raised from room temperature to a predetermined temperature (400
C.). Here, the temperature is raised as follows. First, when a start button (not shown) is turned on by an operator, fuel for combustion such as hydrocarbons is supplied to the burner B by the instruction of the control unit 40, and the air fan F2 is driven to generate combustion air. The high-temperature combustion gas is generated by being supplied and burned by the burner B. This combustion gas is supplied to the space 300
And the reforming reaction tank 10 is heated.

As the temperature rise proceeds, a predetermined temperature (for example,
400 ° C. is detected by the temperature sensor Se1. )
, The raw fuel supply pump P1, the water pump P2, and the air fan F1 are driven by the instruction of the control unit 40 to start supplying the raw fuel, water, and reaction air, and gradually become a steady operation state. Stabilize to get closer. That is, at this stage, the reaction tank is heated both from the inside of the catalyst layer by the combustion heat of the partial oxidation reaction and from the outside of the catalyst layer by the combustion of the burner B.

Here, the reforming catalyst layer 100 is heated to a predetermined temperature (55
When the temperature reaches about 0 ° C.), the supply of the fuel for the burner B is stopped, and the combustion of the burner B is stopped. Then, the supply amounts of the raw fuel, air, and water become predetermined amounts so that the burner B is operated and the steady operation is performed independently only by the combustion heat of the partial oxidation reaction without supplementing heat from the outside. Is controlled as follows.

(2) Steady State Operation The supply amounts of the raw fuel, air and water supplied during the steady state operation are controlled as follows, and the generation of the reformed gas is performed stably. The controller 40 controls the raw fuel supply pump P1, the air fan F1,
Each flow rate is set by controlling the driving force of the water pump P2.

First, the raw fuel supply amount of the raw fuel supply pump P1 is adjusted so that the fuel (hydrogen gas) utilization rate in the fuel cell 50 becomes a predetermined value (for example, 80%).
0 is set according to the load current. Next, the control unit 40 controls the air amount of the air fan F1 based on the measurement data of the air flow meter so that the air-fuel ratio becomes a predetermined ratio.

This ratio (air-fuel ratio) is set by the operator in advance, and is set so that the heat of combustion required for the partial oxidation reaction can sufficiently obtain the heat required for the steam reforming reaction. It is set to a value that allows the hydrogen production apparatus to operate autonomously and steadily by the combustion heat of the partial oxidation reaction alone without operating the burner B, that is, a value that causes an exothermic reaction in the entire reaction system (for example, a value exceeding 11) Is done. This will be described later.

The water flow rate of the water pump P2 depends on the set value of the fuel flow rate and the steam-carbon ratio (hereinafter referred to as S
Abbreviated as / C. ) Is set based on the setting value. The set value of S / C can be set arbitrarily, and it is desirable that the amount of water is large. However, the combustion heat in the partial oxidation reaction, the latent heat of evaporation of water, and the reaction heat of the steam reforming reaction are balanced. It is desirable to set it in such a range. Here, the operation is performed with S / C = 1.

During such a steady operation, the pipe L3
The cold raw fuel mixture flowing through the second buffer layer 1
The cold raw fuel mixture is heated by heat exchange with the hot reformed gas in 20. Then, when passing through the reforming reaction layer 100, steam is generated by receiving the reaction heat of the reforming catalyst layer 100. In other words, by effectively utilizing the sensible heat of the reaction layer in the device, the raw fuel and air can be heated with a simple configuration without using a special heating device such as a boiler, and the steam required for the reforming reaction is generated. Will be done.

On the other hand, the reformed gas supplied to the shift reaction tank 20 exchanges heat with the cold raw fuel mixture flowing in the pipe L3 to a temperature (250 ° C. to 300 ° C.) suitable for the shift reaction.
(° C). The shift reaction is performed by a reaction with the residual steam in the reformed gas. this is,
This is because the concentration of carbon monoxide CO, which is a by-product of the steam reforming reaction, is low, so that even if the residual amount of steam is small, the reaction can be sufficiently performed using this residual amount.

[Relationship between air-fuel ratio and heat value in reforming reaction tank] Next, the relationship between air-fuel ratio (butane / air) and heat value in the reforming reaction tank will be specifically described. FIG.
FIG. 4 is a characteristic diagram illustrating a relationship between a calorific value (W, a theoretical value) and an air-fuel ratio when the hydrogen production apparatus is operated with the S / C kept constant and the air-fuel ratio changed.

This characteristic diagram is derived by the following procedure. The butane reforming reaction (partial oxidation reaction and steam reforming reaction) is performed according to the following reaction formula 4 and the reaction path shown in FIG. It was derived assuming that it would be implemented.

[0045]

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First, the heat required for butane reforming is the sensible heat, the latent heat of vaporization of water, and the heat of reaction required for raising the temperature of the reactants butane, air and water (heating from T0 to T1). The heat of reaction is determined by the composition of the reactant and product (reformed gas) and the reaction temperature (T
Calculated based on 1). The composition of the product is assumed to reach equilibrium as shown in FIG. 5 at the reaction temperature T1 (in FIG. 5, the equilibrium constant of each reaction is represented by Kp1 and Kp2), The thermal mass balance calculation was performed using the supply temperature (T0), the reaction temperature (T1) and the reaction pressure (P) as input parameters.

FIG. 3 is a graph based on the above calculations. In FIG. 3, a minus (-) area of the calorific value indicates a heating state. As shown in FIG.
If only the heat balance between the partial oxidation reaction, which is an exothermic reaction, and the steam reforming reaction, which is an endothermic reaction, even if the amount of air is small, it is exothermic as shown by the line (◆-◆) in the figure. The combustion heat of the partial oxidation reaction is used not only for the steam reforming reaction but also for the latent heat of evaporation of water and the temperature rise of the reactants. If it is less than the above, an endothermic reaction will occur as represented by the (xx) line in the figure.

Therefore, the autonomous operation becomes possible only when the air-fuel ratio is set to a value larger than 11. Of course,
If the calorific value is supplemented by the burner B, it is needless to say that the operation can be performed even if the air-fuel ratio is set to an endothermic reaction region (a value smaller than 11) as the whole reaction system. The operating cost is slightly increased by the amount of the combustion fuel of B.

[Other effects] Since the water in the pipe L3 and the gas in the reforming catalyst layer 100 are countercurrent as described above,
The temperature difference between the inlet side and the outlet side in the reforming catalyst layer 100 is small. That is, the inlet side is warmed by the heated raw fuel mixture, and the outlet side is cooled by the raw fuel mixture flowing through the pipe L3.
The temperature difference becomes smaller in the flow direction of the reaction gas (vertical direction, the upstream side to the downstream side in the reaction progress direction). As a result, the reforming reaction is performed uniformly, the local progress of the reaction is prevented, and the catalyst is partially prevented from being deteriorated.

Further, as in the case of the reforming catalyst layer, the temperature in the shift catalyst layer is also made uniform to some extent in the flow direction of the reaction gas. [Embodiment 2] The hydrogen production apparatus of the present embodiment employs a double cylindrical tube structure similar to the hydrogen production apparatus in which a selective oxidation reaction tank (CO remover) is provided instead of the shift reaction tank. It is the device body.

In the selective oxidation reaction tank, carbon monoxide CO is removed by a selective oxidation reaction as shown in the following chemical formula 5.

[0052]

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In this embodiment, the reforming catalyst layer 100 is
By operating at a low temperature of 00 ° C. or lower, the amount of carbon monoxide CO by-produced by the reforming reaction is reduced by shifting the chemical equilibrium of Chemical Formula 1 to the left. Therefore, even without a shift reaction tank (CO converter), only one reaction tank (CO remover) responsible for the selective oxidation reaction can reduce the carbon monoxide CO concentration to such an extent that the power generation of the polymer electrolyte fuel cell is not hindered. It can be reduced sufficiently.

The operation temperature is controlled by the temperature sensor Se1.
In order to detect the temperature and to reach a predetermined temperature of 500 ° C. or less,
The water supply amount is calculated by the control unit based on data indicating the relationship between the operating temperature and the water amount experimentally obtained in advance, and the water amount is set based on the calculation result. In addition, the operating conditions such as the amount of air and the space velocity are set so that sufficient oxygen is supplied to the selective oxidation reaction on the downstream side in the flow direction of the reaction gas.

By supplying air in this manner, the selective oxidation reaction is carried out using the remaining oxygen in the reformed gas, so that it is not necessary to forcibly supply air to the selective oxidation reaction tank again with a fan or the like. This also contributes to simplification of the device configuration. In addition,
The operating conditions are obtained experimentally with respect to the supply amount of raw fuel, the supply amount of steam, the catalytic activity of the reforming catalyst layer, the reaction temperature, and the like.

In storing the shift reaction tank, it is customary to purge an inert gas to prevent the catalyst from being oxidized. However, in the selective oxidation reaction tank, the catalyst is oxidized by air. Even if there is no problem, such an operation as purging the inert gas is unnecessary and the operator can easily handle the operation. In addition, the reforming reaction tank 10
Since is operated at low temperature, there is also an advantage that the container of the reaction tank can be constituted by a low-cost material (for example, SUS).

Next, the operation at a low temperature will be exemplified. During the steady operation, the S / C was set to a predetermined value of 2 to 5, the air-fuel ratio was set to 6, and the burner B was operated so that the reaction temperature reached 500 ° C. while operating appropriately. Table 1 below shows the measurement results of the gas composition immediately downstream of the reforming reaction tank when the steady operation was performed. In addition, each S / C of Table 1
The numerical value of the gas with respect to is expressed in volume% per unit volume.

[0058]

[Table 1]

As shown in Table 1, when the reforming temperature is 500.degree. C., it is 1.6 to 2.4%, whereas when the reforming temperature is 600.degree. ℃ is CO
It can be seen that the concentration is reduced. Focusing on the carbon monoxide CO concentration at each set value of S / C, setting the S / C to a large value (increase the amount of water vapor) increases the hydrogen generation amount by 32.7, 38.4, and 42. It can be seen that the carbon monoxide CO concentration can be further reduced by increasing to 0.5,45.5%.
When the hydrogen production apparatus is used in a polymer electrolyte fuel cell system, setting such a large S / C has an advantage that humidification of the polymer electrolyte fuel cell is not required.

As described above, since the reformed gas immediately after the reforming reaction has a lower carbon monoxide CO content than at a high temperature (600 ° C.), the selective oxidation reaction alone does not sufficiently interfere with the operation of the fuel cell. It is possible to reduce the CO concentration to the extent that there is no occurrence. [Embodiment 3] The hydrogen production apparatus according to the present embodiment
The other configuration is the same as that of the first embodiment except that the structure of the apparatus main body 60 is slightly different, so only the differences will be described.

FIG. 6 is a sectional view of an essential part of the hydrogen production apparatus. Note that the shift reaction tank is not shown for simplicity. As shown in FIG. 6, the hydrogen production device main body 60 includes a raw fuel mixture supply pipe L7, a buffer layer 61 secured above the reforming catalyst layer 63, the buffer layer 61 and the reforming catalyst layer 63. The buffer layer 62 (corresponding to the first buffer layer 110 according to the first embodiment) secured below communicates with the buffer layer 62 and is dispersed and disposed so as to penetrate the reforming catalyst layer 63. With piping L8 ...
The raw fuel mixture from the pipe L7
, And is distributed from the buffer layer 61 to the pipes L8... To flow into the buffer layer 62.

The buffer layer 6 for recovering the reformed gas corresponding to the second buffer layer 120 in the first embodiment
4 is secured between the buffer layer 61 and the reforming catalyst layer 63. The basic operation of the hydrogen production apparatus having such a configuration is the same as that of the first embodiment,
The raw fuel mixture is supplied to the reforming catalyst layer 100 through a plurality of pipes L8.
Is distributed uniformly in the surface direction of the reforming catalyst layer 100.

[Embodiment 4] This embodiment has the same configuration as that of the hydrogen production apparatus of Embodiment 1 except that the temperature raising mechanism is different, so only the differences will be described. FIG. 7 is a sectional view of a main part of the hydrogen production apparatus. For convenience, the reaction tank for reducing the carbon monoxide CO concentration is:
Not shown.

As shown in FIG. 7, the apparatus main body of the hydrogen production apparatus includes a combustion section 70 (composed of a burner and a combustion catalyst) for burning fuel to generate high-temperature combustion gas. The portion 70 is adjacent to the first buffer layer 110 via a partition plate 71 (for example, a net material) having an appropriate number of through holes (not shown). Through the buffer layer 110, the reforming catalyst layer 10
0 is supplied.

Further, the hydrogen producing apparatus is provided with
A pipe L9 for supplying a mixture of fuel and air to the fuel tank and a pipe L10 for supplying a mixture of fuel and air to the reforming catalyst layer 100 and forming a spiral shape inside the reforming reaction tank 10 (corresponding to the pipe L3). Pipes), control valves V1 and V2 inserted in the pipes L9 and L10 for switching the flow paths between the pipes L9 and L10, and these control valves V1 and V2 based on the temperature detected by the temperature sensor Se1. And a control unit 75 for controlling V2.

A mixture of the raw fuel from the pump P1 and the air from the fan F1 in the raw fuel / air mixing section 15 is fed into the pipe L9. The combustion fuel and air to the combustion unit 70 have the same raw fuel and air for the reforming reaction and the same supply driving source. Based on the temperature of the reforming catalyst layer 100, the control valves V1 and V2 are controlled by the control unit 75. Control is switched from supply to the combustion section 70 to supply to the reforming reaction tank 10.

Specifically, at the time of startup, only the control valve V1 is opened to supply the mixture of the raw fuel and air, and the fuel is ignited and completely burned by energizing the ignition plug G. Then, when the temperature of the reforming catalyst layer reaches a predetermined temperature (for example, 400 ° C.), the control valve V1 is closed, the control valve V2 is opened, and the water pump P2 is also driven to mix water to form the reforming catalyst layer. The raw fuel mixture is supplied to stabilize the reaction environment and approach a steady state. When stabilized, the steady operation is performed while controlling the supply amounts of the raw fuel, air and water.

As described above, instead of flowing outside the reforming catalyst layer and the shift catalyst layer to heat the catalyst layer, the catalyst itself is brought into direct contact with the high-temperature combustion gas to directly and directly contact the reforming catalyst layer. By heating from the inside, the temperature can be raised quickly and uniformly without increasing the size of the apparatus main body unlike the external heating. Moreover, since the fuel used for the reforming reaction is sent out by the same pump P1 as the fuel burned by the burner B, the burner B
There is also an effect that it is not necessary to provide a fuel supply pump or the like, and the device configuration is simplified.

It is to be noted that the combustion gas of the combustion section 70 can be supplied not only to the reforming catalyst layer but also to a shift reaction layer, a selective oxidation catalyst layer, etc. disposed downstream of the reforming catalyst layer in the flow direction of the reforming gas. In this case, the temperature of the reaction layers can be quickly raised. [Embodiment 5] The hydrogen production apparatus according to the embodiment has a configuration in which the raw fuel is preheated and the steam is generated in a pipe section around which a reforming catalyst is disposed. Such a hydrogen production apparatus is configured to perform preheating of raw fuel and generation of steam in a packed bed of heat transfer particles provided around a reforming catalyst layer. Hereinafter, only differences from the above embodiment will be described.

FIG. 8 is a sectional view of the hydrogen production apparatus main body according to the present embodiment. As shown in FIG. 8, between the reforming reaction tank 10 and the shift reaction tank 20, a raw fuel mixture heating tank 80 having a cylindrical body having a bottom and a bottom is closely attached to the reforming catalyst tank 10. It is arranged in the state where it did. The raw fuel mixture heating tank 80 has a pair of mesh members 8 at the center of the cylindrical body.
A heat transfer layer 82, which is filled with a good heat transfer material 82b such as metal particles, is provided between 2a, on which a buffer layer 81 for diffusing the introduced cold raw fuel mixture and the heat transfer layer A buffer layer 83 from which the raw fuel mixture passed through 82 is recovered is secured.

The buffer layer 81 is located around the second buffer layer 120,
The raw fuel mixture inside is preheated before being introduced into the heat transfer layer 82 by heat exchange with the high temperature reformed gas generated by the reforming reaction, and conversely, the reformed gas is cooled to a temperature suitable for the shift reaction. Is done. The heat transfer layer 82 is located around the reforming catalyst layer 100, and becomes a high-temperature layer by transferring heat of combustion due to a partial oxidation reaction of the reforming catalyst layer 100. Then, the raw fuel mixture from the buffer layer 81 is further heated in the high-temperature heat transfer layer 82 to generate steam.

The buffer layer 83 communicates with the first buffer layer 110, and the heated raw fuel mixture from the heat transfer layer 82 is recovered by the buffer layer 83 and is mixed with the first buffer layer 110. Is distributed to the reforming catalyst layer 100 and subjected to the reaction. As described above, in the hydrogen production apparatus according to the present embodiment, the raw fuel mixture heating tank 80 is provided around the reforming catalyst layer 100, and the combustion heat in the reforming catalyst layer 100 is effectively used based on this structure. The raw fuel and air are heated or steam is generated.

It is to be noted that the raw fuel mixture heating tank 80 is provided around the reforming catalyst tank 10 as in the present embodiment, and the raw fuel mixture heating tank 80 is provided in the reforming catalyst layer as in the first to fourth embodiments. The configuration in which the fuel heating tank is inserted (internally installed) is a more desirable form from the viewpoint of heat transfer efficiency and from the viewpoint that the apparatus is compact. [Modifications] It is needless to say that the present invention is not limited to the above embodiments, but can be implemented in various forms without departing from the gist of the present invention, and the following modifications are possible.

That is, (1) In the operation of the hydrogen production apparatus according to the above-described embodiment, the S / C and the air-fuel ratio are not limited to the above-mentioned values, but can be arbitrarily set according to the operation conditions. (2) In the above embodiment, the hydrogen production apparatus in which the catalyst layer for the partial oxidation reaction and the catalyst layer for the steam reforming reaction are integrated is shown, but the present invention is not limited to this. In the case where the layer and the catalyst layer for the steam reforming reaction are independently provided separately and the partial oxidation reaction and the steam reforming reaction are sequentially performed, the raw fuel mixture is similarly applied to the catalyst layer for the partial oxidation reaction. A similar effect can be obtained by providing a passage for heating the. In this case, since the heat of the partial oxidation reaction is likely to be lost when the heat is transferred to the steam reforming layer, a larger air-fuel ratio is set to generate more combustion heat or the burner B is operated. It is desirable to operate while supplementing the amount of heat from outside.

(3) The reforming catalyst layer 100 is a layer filled with filler particles. However, the present invention is not limited to this. For example, a plurality of heat transfer fin plates having a metal catalyst supported on the surface thereof may be used. The catalyst layer may be provided. However, in this case, at the stage of manufacturing the structure in which the pipe L3 is inserted, the heat transfer fins must be partially cut or formed, so that the simplicity of device manufacturing is taken into consideration. It is more preferable to use a filler.

(4) Further, in the above embodiment, both heating of fuel and generation of water vapor are performed in the same passage made of piping or a packed bed of good heat transfer using sensible heat of the partial oxidation reaction. The heating of the fuel and the generation of steam can be performed in separate passages, or the sensible heat of the partial oxidation reaction can be used for either heating of the fuel or generation of steam. Also in this case, there is no need to separately provide a heating means for utilizing the sensible heat of the partial oxidation reaction, so that the effect of simplifying the configuration can be obtained.

[0077]

As described above, the hydrogen production apparatus according to the present invention is characterized in that, in the hydrogen production apparatus, a partial oxidation section provided with a partial oxidation reaction layer for partially oxidizing fuel is supplied to the hydrogen production apparatus. A reforming section provided with a steam reforming catalyst layer that generates a hydrogen-rich reformed gas by performing a steam reforming reaction on fuel;
A fuel supply unit for heating the fuel and supplying the heated fuel to the partial oxidation unit; and a steam supply unit for generating steam and supplying the steam to the reforming unit. And at least one of the steam supply means uses heat generated by the partial oxidation reaction as a heat source.

Alternatively, a steam reforming reaction is performed on the fuel in response to the supply of steam to generate a hydrogen-rich reformed gas and a partial oxidation reaction for partially oxidizing the fuel using oxygen is performed. And a fuel supply unit for heating the fuel and supplying the heated fuel to the steam reforming unit, and generating steam to supply the steam to the reforming unit. Wherein at least one of the fuel supply means and the water vapor supply means uses heat generated by a partial oxidation reaction as a heat source.

In any of these cases, the sensible heat of the partial oxidation reaction, which is an exothermic reaction, can be effectively used without providing a heating device such as a boiler or heat exchanger for heating the fuel or generating steam. Heating and steam generation, fuel heating and steam generation can be performed with a simple configuration without complicating the device configuration. Further, in the case where the partial oxidation reaction occurs simultaneously, the steam supply means is provided with a steam generation unit that generates steam using heat generated in the partial oxidation unit, and the flow of steam in the steam generation unit is controlled. Is made to flow countercurrent to the flow of the reaction gas in the partial oxidation section reaction, so that the heat of the hot steam is transferred to the fuel inlet portion of the steam reforming catalyst layer, while the outlet portion is formed by cold water. Since there is a cooling effect, there is an effect that the temperature of the steam reforming catalyst layer in the reaction gas flow direction is made uniform.

If the steam generating section is provided in the steam reforming catalyst layer, the apparatus becomes more compact,
The sensible heat of the partial oxidation reaction is efficiently transferred to the steam generator. Further, the fuel supply means is provided with a fuel heating unit for heating fuel using heat generated in the partial oxidation reaction as a heat source, and the flow of the fuel in the fuel heating unit with respect to the flow of the reaction gas in the partial oxidation reaction. The countercurrent flow has the effect of making the temperature of the steam reforming catalyst layer in the flow direction of the reaction gas uniform, as in the case of the steam generation section.

If the fuel heating section is provided in the steam reforming catalyst layer similarly to the steam generation section, there are effects such as a reduction in the size of the apparatus. Further, from the viewpoint of making the apparatus compact, it is desirable that the steam generation section and the fuel heating section are formed as a common passage. This passage, for example,
A simple pipe may be used, or the pipe may be filled with good heat transfer particles to improve thermal conductivity, and the form is not particularly limited.

Further, the hydrogen production apparatus of the present invention has a fuel combustion section for burning fuel to generate combustion gas, wherein the reforming catalyst is communicated with the fuel combustion section by a combustion gas passage, and Is introduced into the reforming catalyst from the combustion gas passage, and the reforming catalyst is heated, so that the temperature can be quickly and uniformly increased from the inside of the catalyst layer without increasing the size of the apparatus body.

Further, a partial oxidation reaction step of reacting the fuel of the present invention with oxygen to cause a partial oxidation reaction is performed, and the fuel is subjected to a steam reforming reaction at 500 ° C. or lower using combustion heat generated by the partial oxidation reaction. A reformed gas generating step of generating a hydrogen-rich reformed gas; and a selective oxidation step of selectively oxidizing by reacting carbon monoxide in the reformed gas with residual oxygen in the reformed gas. According to the hydrogen production method, the carbon monoxide CO concentration can be sufficiently reduced with a small apparatus configuration without providing a CO converter. In addition, since the selective oxidation reaction step is performed using the residual oxygen in the reformed gas, there is no need to forcibly supply air again with a fan or the like for the selective oxidation reaction, which contributes to simplification of the apparatus. .

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a main body configuration of a hydrogen production apparatus according to one embodiment.

FIG. 2 is a block diagram showing a configuration of a fuel cell system to which the hydrogen production apparatus is applied (including a cross-sectional view of a main part of the hydrogen production apparatus).

FIG. 3 is a characteristic diagram showing a relationship between a calorific value (W) and an air-fuel ratio when the hydrogen production apparatus is operated while changing an air-fuel ratio.

FIG. 4 is a schematic view of a reaction path of a butane reforming reaction.

FIG. 5 is a schematic diagram showing an equilibrium state between a butane reforming reaction and a shift reaction.

FIG. 6 is a cross-sectional view of a main part of a hydrogen production apparatus according to another embodiment.

FIG. 7 is a sectional view of a main part of still another hydrogen production apparatus.

FIG. 8 is a sectional view of a main part of still another hydrogen production apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 hydrogen production apparatus main body 10 reforming reaction tank 15 raw fuel / air mixing section 20 shift reaction tank 30 heating tank 40 control section 50 fuel cell 60 hydrogen production apparatus main body 61 buffer layer 62 buffer layer 63 reforming catalyst layer 64 buffer layer 70 Combustion unit 71 Partition plate 80 Raw fuel mixture heating tank 81 Buffer layer 82 Heat transfer layer 83 Buffer layer 100 Reforming catalyst layer 101 Container 110 First buffer layer 120 Second buffer layer 200 Shift catalyst layer 210 Third buffer layer 220 Fourth Buffer layer P1 Raw fuel supply pump P2 Water pump M1 Raw fuel flow meter M2 Air flow meter M3 Water flow meter F1, F2 Fan Se1 Temperature sensor

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Katsuya Oda 2-5-2-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Yasuo Miyake 2-5-2 Keihanhondori, Moriguchi-shi, Osaka No. 5 Sanyo Electric Co., Ltd.

Claims (9)

[Claims] 1. A partial oxidation unit having a partial oxidation reaction layer for partially oxidizing a fuel, and a steam reforming unit that receives a supply of steam and performs a steam reforming reaction on the fuel to generate a hydrogen-rich reformed gas. A reforming section provided with a catalyst layer, a fuel supply means for heating the fuel and supplying the heated fuel to the partial oxidation section, and a steam for generating steam and supplying the steam to the reforming section A hydrogen supply device, wherein at least one of the fuel supply unit and the water vapor supply unit uses heat generated by the partial oxidation reaction as a heat source. 2. A steam reforming system that receives a supply of steam to perform a steam reforming reaction on a fuel to generate a hydrogen-rich reformed gas, and also involves a partial oxidation reaction for partially oxidizing the fuel using oxygen. A reforming section provided with a catalyst layer, fuel supply means for heating the fuel and supplying the heated fuel to the reforming section, and steam for generating steam and supplying the steam to the reforming section A hydrogen production apparatus, comprising: a supply unit; and at least one of the fuel supply unit and the steam supply unit uses heat generated by a partial oxidation reaction as a heat source. 3. The steam supply unit has a steam generation unit that generates steam by using heat generated by the partial oxidation reaction as a heat source, and the flow of the steam in the steam generation unit is in the steam reforming catalyst layer. 3. The hydrogen production apparatus according to claim 2, wherein the flow is countercurrent to the flow of the reaction gas in the step. 4. The fuel supply unit has a fuel heating unit that heats fuel by using heat generated by the partial oxidation reaction as a heat source, and the flow of the fuel in the fuel heating unit is controlled by the steam reforming catalyst layer. 4. The hydrogen production apparatus according to claim 2, wherein the flow is countercurrent to the flow of the reaction gas. 5. The hydrogen production apparatus according to claim 2, wherein the steam generation section is provided inside the steam reforming catalyst layer. 6. The hydrogen production apparatus according to claim 2, wherein the fuel heating section is provided inside the steam reforming catalyst layer. 7. The fuel cell according to claim 2, wherein the steam generation section and the fuel heating section are configured by a common passage.
The hydrogen production apparatus according to any one of the above. 8. A hydrogen production apparatus comprising a reforming catalyst for producing a hydrogen-rich reformed gas by performing a steam reforming reaction on a fuel, comprising a fuel combustion section for burning a fuel to produce a combustion gas. The reforming catalyst is communicated with the fuel combustion section by a combustion gas passage, the combustion gas is introduced from the combustion gas passage to the reforming catalyst, and the reforming catalyst is heated. Manufacturing equipment. 9. A partial oxidation reaction step in which a fuel is reacted with oxygen to cause a partial oxidation reaction, and a steam reforming reaction is performed on the fuel at 500 ° C. or lower using combustion heat generated in the partial oxidation reaction to form a hydrogen-rich fuel. A reformed gas generating step of generating a reformed gas, and a selective oxidation step of selectively oxidizing by reacting carbon monoxide in the reformed gas with the remaining oxygen in the reformed gas. Hydrogen production method.