JP2002160902A - Device for generating hydrogen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To actualize a stable state of combustion at a burner and an excellent property of exhausted combustion gas concerning ingredients and change in flow rate of produced gas at the start of a hydrogen generating device which comprises a reformer, a converter and a cleaning part and whose structure is the produced gas coming from the cleaning part is supplied to the burner. SOLUTION: A device for generating hydrogen can actualize a stable state of combustion at a burner and an excellent property of the exhausted combustion gas by having a passageway which leads the produced gas emitted from the device tot the burner and a detector which measures temperature at the reformer, estimating the flow rate of inflammable gas in the produced gas by signals from a raw materials supplying part and the temperature detecting part in the reformer and controlling the amount of air supplied from an air supplying part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to natural gas, LP
The present invention relates to a hydrogen generator that uses a hydrocarbon-based substance such as G, gasoline, naphtha, kerosene, or methanol as a main raw material and generates a hydrogen-rich gas to be supplied to a hydrogen utilization device such as a fuel cell.

[0002]

2. Description of the Related Art A method of starting a conventional hydrogen generator for a fuel cell will be described below with reference to FIG.

[0003] Reference numeral 1 denotes a raw material supply unit, and 2 denotes a water supply unit, which is connected to a reforming unit 3 in which a reforming catalyst is filled. The raw material supplied by the raw material supply unit 1 flows out of the reforming unit 3, flows into the conversion unit 4 filled with the shift catalyst, and is further converted.
From the gas flows into the purification section 5 filled with the CO removal catalyst. The gas flowing out of the purification section 5 passes through the three-way valve 6 as a generated gas, and one of the flow paths is configured to lead from the hydrogen generator to the fuel cell 7 and the other to the burner 8 installed near the reforming section 3. are doing. The burner 8 is provided with 9 fuel supply units and an air supply unit 10 for supplying combustion air. The combustion gas in the burner 8 is exhausted from an exhaust port 11 provided in the reforming section 3.

At the time of startup, the three-way valve 6 supplies the generated gas to be sent from the purifying unit 5 to the burner 8 at the time of startup. The ignition device (not shown in the drawing) is supplied while the combustion air is supplied from the air supply unit 10. The fuel is supplied from the fuel supply unit 9 while performing the ignition operation in step (1) to form a flame in the burner 8. After confirming the stable state of the flame, the raw material supply unit 1
By supplying more raw material, the burner 8 has a fuel supply unit 9.
The fuel supplied from the reactor and the raw material supplied from the raw material supply unit 1 combust the generated gas that has passed through the reforming unit 3, the shift unit 4, and the purification unit 5 to heat the reforming unit 3. Thereafter, by reducing the amount of fuel from the fuel supply unit 1 and stopping the operation, a flame is formed only by the supply of the raw material from the raw material supply unit 1, and the reforming unit 3,
The temperature of the shift unit 4 and the purification unit 5 is raised to an optimum temperature state to start the hydrogen generator.

At this time, the supply amount of air is supplied in accordance with the supply amount of the raw material from the raw material supply unit 1. However, in this method of controlling the amount of air, since the amount of air corresponds to the amount of raw material supplied, the amount of air does not sufficiently correspond to the flow rate of combustible gas in the product gas to be actually burned. The characteristics of the combustion exhaust gas may be deteriorated or an unstable combustion state may be caused.

[0006]

The above problems will be further described.

The gas components and the gas flow rate in the produced gas are determined by the reaction state of each catalyst, that is, the temperature of each catalyst. For example, when methane is used as a source gas, the reforming reaction in the reforming section is mainly represented by (Equation 1) and (Equation 2).

(Equation 1) CH ₄ + 2H ₂ O → 4H ₂ + CO ₂ (Equation 2) CH ₄ + H ₂ O → 3H ₂ + CO When the temperature of the reforming catalyst is low and the reforming reaction does not occur,
The product gas sent from the hydrogen generator to the burner is methane supplied as a raw material. However, if the temperature rises to a temperature at which the reforming reaction is sufficiently performed, the reformed gas delivered from the reforming section mainly becomes hydrogen and carbon dioxide or carbon monoxide from (Equation 1) and (Equation 2). The total flow will be 4-5 times the supplied methane. Until the temperature of the reforming catalyst rises sufficiently, the product gas component and the flow rate will be values between them, and the reaction in the shift section and the purification section will be added to this, so the product gas will depend on the temperature of each section. It changes in various ways.

As described above, since the flow rate of the combustible gas in the generated gas changes due to the change in the component and the flow rate of the generated gas depending on the temperature of each part, excess or deficiency occurs in the air amount corresponding to the raw material supply amount, and the burner is good. It was difficult to always maintain a good combustion state. Especially, when the temperature of the reforming catalyst is around 400 ° C, 10deg
As the reaction rate rises by several tens of percent due to the temperature rise, the gas flow rate sent from the reforming section sharply increases, and a large amount of combustible gas present in the shift section and the purification section is pushed out to the burner section.
For this reason, the air amount corresponding to the raw material supply amount is considerably insufficient, and the flame tends to be unstable, and sometimes there is a possibility of misfire.

The present invention has been made to solve these problems, and an object of the present invention is to provide a hydrogen generator which stably burns a gas produced from the hydrogen generator with a burner and which is excellent in operability and convenience. It was done.

[0011]

SUMMARY OF THE INVENTION In order to solve this problem, the present invention relates to a reforming apparatus having a raw material supply section for supplying a hydrocarbon-based raw material and a water supply section for supplying water, the reforming catalyst being filled with a reforming catalyst. And a fuel supply unit for supplying a hydrocarbon-based fuel and an air supply unit for supplying air, and a burner for heating the reforming unit. A flow path for guiding gas to the burner; and a reforming temperature detecting section for measuring a temperature of the reforming section, wherein a flammable gas in the product gas is supplied by a signal from the raw material supply section and a signal from the reforming temperature detecting section. The flow rate of the reactive gas is predicted, and the amount of air supplied from the air supply unit is controlled.

[0012] The present invention also includes a shift section filled with a shift catalyst, which is provided downstream of the reforming section, and a shift temperature detecting section for measuring the temperature of the shift section, wherein a signal from the raw material supply section is provided. And predicting the flammable gas flow rate in the generated gas by the signal from the reforming temperature detection unit and the signal from the shift temperature detection unit, and controlling the amount of air supplied from the air supply unit. Is what you do.

[0013] The present invention further comprises a purifying section provided downstream of the shift section and filled with a purifying catalyst, and a purifying temperature detecting section for measuring the temperature of the purifying section. A signal from the reforming temperature detector, a signal from the shift temperature detector, and a signal from the purification temperature detector predict a flow rate of combustible gas in the generated gas, and supply air from the air supply unit. The amount is controlled.

Further, the present invention predicts a total flow rate of the combustible gas in the burner from a predicted flow rate of the combustible gas in the generated gas and a fuel flow rate based on a signal from the fuel supply unit. It is characterized in that the amount of air supplied from the supply unit is controlled.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a configuration diagram of a hydrogen generator according to Embodiment 1 of the present invention. Reference numeral 1 denotes a raw material supply unit, and 2 denotes a water supply unit, which is connected to a reforming unit 3 in which a reforming catalyst is filled. The raw material supplied by the raw material supply unit 1 flows out of the reforming unit 3 and flows into the conversion unit 4 filled with the shift catalyst, and the gas flowing out of the shift unit 4 is CO.
It flows into the purification section 5 filled with the removal catalyst. The gas flowing out of the purification unit 5 passes through the three-way valve 6 as a generated gas. One of the gas flows from the hydrogen generator to the fuel cell 7 and the other flows to a burner 8 installed near the reforming unit 3. Make up. The burner 8 is provided with a fuel supply unit 9 and an air supply unit 10 for supplying combustion air. The combustion gas in the burner 8 is exhausted from an exhaust port 11 provided in the reforming section 3.

Here, the raw material supply unit 1 and the fuel supply unit 9
Is a gaseous hydrocarbon fuel such as natural gas (city gas) or LPG, or a liquid hydrocarbon fuel such as gasoline, kerosene or methanol. However, when a liquid fuel is used, a fuel vaporization unit is required. However, it is possible to configure a vaporization unit that uses conduction heat from the reforming unit 3 and the burner 8 and sensible heat in the combustion exhaust gas. It is.

The flow rates of the raw material supply unit 1, the fuel supply unit 9, and the air supply unit 10 are adjusted by using a pump, a fan, or the like to control the operation thereof, or a valve is provided downstream of the pump, the fan, or the like. Although there is a method of installing a flow regulator, etc., these are shown as respective supply units in the present description.

The arrows in the figure indicate raw materials, reactants,
It shows the direction of flow of fuel material and the like. Further reforming unit 3
Is provided with a reforming temperature detection unit 12 for measuring the temperature of the reforming catalyst, and the air supply amount can be controlled by the air supply unit 10 according to the detected temperature. Here, as the reforming temperature detecting unit 12, a thermocouple, a high-temperature thermistor, or the like can be used.

In the above configuration, the activation of the hydrogen generator will be described below.

In order to supply the generated gas sent from the purifying section 5 to the burner 8 at startup, the flow path of the three-way valve 6 is set to the burner side. In a state where air is supplied from the air supply unit 10, fuel is supplied from the fuel supply unit 9 to form a flame in the burner 8 while performing an ignition operation with an ignition device (omitted in the drawing).

After confirming the stable state of the flame, the raw material is supplied from the raw material supply unit 1 so that the fuel supplied from the fuel supply unit 9 and the raw material supplied from the raw material supply unit 1 are reformed in the burner 8. The section 3, the shift section 4, the purification section 5 and the passing product gas burn to burn the reforming section 3.

Thereafter, the fuel from the fuel supply unit 1 is reduced and stopped, and the temperature of each unit is increased by forming a flame in the burner 8 by the supply of the raw material from the raw material supply unit 1 to obtain an optimal temperature state. Complete the startup of the hydrogen generator.

In the reforming reaction, hydrogen and carbon dioxide are used in a total of 5 moles or 1 mole of methane, or hydrogen and carbon monoxide are used for 1 mole of methane mainly by the two reactions shown in (formula 1) and (formula 2). A total of 4 moles are produced.

FIG. 2 shows the reaction rate of methane with respect to the temperature of the reforming catalyst. It can be seen that the reaction rate of methane rapidly increases near 400 ° C., and the reforming reaction proceeds rapidly. From these facts, it is understood that the component and the flow rate of the reformed gas sent out from the reforming section 3 greatly change depending on the temperature of the reforming catalyst. The generated gas delivered from the hydrogen generator is a gas in which the gas near the outlet of the purifying unit 5 closest to the burner 8 is pushed out by the reformed gas.
At about ゜ C, the temperature of the metamorphic section 4 and the purification section 5 is not so high, so that the metamorphic reaction and the selective oxidation reaction are not sufficiently performed.
The reformed gas passes through the shift section 4 and the purification section 5 with little reaction.

Therefore, by predicting the component and flow rate of the reformed gas from the supply amount of the raw material and the temperature of the reforming catalyst, and grasping the change over time, the gas component extruded by the reformed gas in the vicinity of the outlet of the purification unit 5 can be detected. By the prediction, the combustible gas flow rate in the generated gas can be captured.

For example, if methane is supplied at a rate of 1 NL / min as a raw material when the temperature of the reforming catalyst is 400 ° C., the reaction rate of methane becomes 50% from FIG. 2, and (Formula 1) and (Formula 2) are 1
Occurs at a ratio of 0: 1. (The ratio at which (Equation 1) and (Equation 2) occur with respect to the catalyst temperature is not shown.) Therefore, the reformed gas is unreacted methane 0.5 NL / min. NL / min, carbon dioxide from (Equation 1)
It can be considered that the gas composed of 0.45 NL / min and 0.05 NL / min of carbon monoxide is in a temperature state of 400 ° C. from (Equation 2). Similarly, it is possible to calculate the total flow rate of the reformed gas and the flow rates of each component according to the reforming catalyst temperature, and to grasp the change over time. Here, the burner 8
Since the volume of the flow path up to 400 ° C. is known, the reformed gas from the reforming catalyst at 400 ° C. is pushed by the reformed gas generated thereafter, passes through the shift section 4 and the purification section 5 and reaches the burner 8. I know when to do it. Therefore, this reformed gas is supplied to the burner 8
When the flammable gas flow in the reformed gas (methane
0.5NL / min, hydrogen 1.95NL / min, carbon monoxide 0.05NL / min)
Can be calculated, the theoretical air amount for each component can be calculated (theoretical air amount: 4.76NL / min (vs. methane), 4.64
NL / min (relative to hydrogen), 0.12 NL / min (relative to carbon monoxide), and an optimal amount of air can be supplied from the air supply unit 10.

Therefore, the raw material supply unit 1 and the reforming temperature detecting unit 1
2, it is possible to determine an appropriate amount of air to the burner 8 and to supply the air from the air supply unit 10, so that a stable combustion state and good combustion exhaust can be obtained even under conditions in which the flow rate and components of the generated gas change. Gas characteristics can be realized.

FIG. 3 shows that a platinum group-based shift catalyst has CO: 10
%, CO ₂ : 10%, H ₂ : 80% shows the reactivity to the catalyst temperature when a standard gas is supplied. It can be seen that a shift reaction, a reverse shift reaction, and a methanation reaction occur depending on the temperature of the catalyst, and the amounts of CO and CH ₄ are determined.

In order to grasp the reaction state of the shift catalyst, a shift temperature detecting unit 13 is installed in the shift unit 4 to measure the catalyst temperature of the shift unit 4, and the reformed gas is determined by the flow rate of the raw material and the reforming catalyst temperature. From the flow rate and the component of the gas, the flow rate and the component of the metamorphic gas at the outlet of the metamorphic unit 4 can be predicted. If the transformed gas is regarded as the product gas from the hydrogen generator, the flow rate of the combustible gas in the product gas can be more accurately predicted than if the reformed gas is regarded as the product gas.

Therefore, the raw material supply unit 1 and the reforming temperature detection unit 1
Based on the prediction of the reformed gas based on the signal from the second unit 2 and the signal from the shift temperature detecting unit 13, it is possible to more accurately determine an appropriate amount of air to the burner 8 and supply the appropriate amount of air from the air supply unit 10.

FIG. 4 shows a platinum group CO removal catalyst containing CO:
It shows the reactivity with respect to the catalyst temperature when a standard gas of 1%, CO ₂ : 19% and H ₂ : 80% is supplied.
Depending on the temperature of the catalyst, the oxidation reaction or reverse shift reaction
It can be seen that the amount of O is determined.

In order to grasp the reaction state of such a CO removal catalyst, a purification temperature detecting section 14 is installed in the purification section 5 and the catalyst temperature of the purification section 5 is measured. From the flow rate and the component of the transformed gas depending on the catalyst temperature, the flow rate and the component of the generated gas at the outlet of the purification unit 5 can be predicted. Therefore, the flow rate of the combustible gas in the generated gas can be accurately predicted.

Therefore, the prediction of the flow rate and components of the transformed gas based on the signals from the raw material supply section 1 and the reforming temperature detecting section 12 and the signal from the transforming temperature detecting section 13 and the purification temperature detecting section 14
Based on the signal from, the flow rate of the flammable gas in the generated gas is grasped, and the supply of the optimum amount of air from the air supply unit 10 to the burner 8 can be realized.

(Embodiment 2) FIG. 5 is a configuration diagram of a hydrogen generator according to Embodiment 2 of the present invention. The hydrogen generator of Embodiment 1 shown in FIG. Thus, the total flow rate of the flammable gas to the burner 8 is predicted by comprehending the fuel flow rate with the prediction of the flammable gas flow rate in the generated gas.

With this configuration, when fuel is supplied from the fuel supply unit 9 and the amount of combustion in the burner 8 is increased, for example, when the temperature of the reforming unit 3 does not sufficiently rise only by supplying the raw material, the fuel supply unit The flow rate of the combustible gas to the burner 8 is predicted by grasping the fuel flow rate from the signal from the fuel gas 9 and predicting the flow rate of the combustible gas in the generated gas, and an appropriate amount of air is supplied from the air supply unit 10. By doing so, a stable state of combustion in the burner 8 and good combustion exhaust gas characteristics can be realized.

The temperature detecting section of each section may be provided not at one place but at a plurality of places to more precisely grasp the temperature state of the catalyst and predict the state of the generated gas.

In the above description, the present invention has been described with respect to the start-up of the hydrogen generator. However, during normal operation, when the amount of hydrogen generation is changed, for example, when the output of the fuel cell is changed, etc. It can also be applied when the temperature changes.

[0039]

As described above, according to the present invention, in the configuration in which the generated gas delivered from the hydrogen generator at the time of startup is supplied to the burner, the reformed gas component and the flow rate are determined by the supply amount of the raw material and the temperature of the reforming section. By grasping the time change of the fuel gas, the flow rate of the combustible gas in the produced gas is predicted, and by supplying an appropriate amount of air, a stable combustion state and good combustion exhaust gas characteristics are realized.

Furthermore, by taking into account the reaction in the metamorphic section and the reaction in the purifying section by measuring the temperature in the metamorphic section and the purifying section,
The purpose is to more accurately predict the flow rate of the combustible gas in the produced gas and to supply the optimum amount of air.

In addition, even when fuel is supplied, the amount of air is controlled by grasping the total flow rate of combustible gas in the burner by predicting the fuel supply amount and the flow rate of combustible gas in the generated gas, thereby controlling the combustion. And a good combustion exhaust gas characteristic.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a hydrogen generator according to Embodiment 1 of the present invention.

FIG. 2 is a graph showing a conversion rate of methane by a reforming catalyst.

FIG. 3 is a graph showing reactivity by a shift catalyst.

FIG. 4 is a graph showing the reactivity of a CO purification catalyst.

FIG. 5 is a configuration diagram of a hydrogen generator according to Embodiment 2 of the present invention.

FIG. 6 is a configuration diagram of a conventional hydrogen generator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Raw material supply part 2 Water supply part 3 Reforming part 4 Transformation part 5 Purification part 6 Three-way valve 7 Fuel cell 8 Burner 9 Fuel supply part 10 Air supply part 11 Exhaust port 12 Reformation temperature detection part 13 Transformation temperature detection part 14 Purification Temperature detector

Continued on the front page (72) Inventor Takeshi Tomizawa 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F-term (reference) 4G040 EA02 EA03 EA06 EB12 EB31 EB32 EB43 4G140 EA02 EA03 EA06 EB12 EB31 EB32 EB02 5H01A KK42 MM12 MM13

Claims (4)

[Claims] 1. A reforming section having a raw material supply section for supplying a hydrocarbon-based raw material and a water supply section for supplying water, and a reforming section filled with a reforming catalyst; a fuel supply section for supplying a hydrocarbon-based fuel; In a hydrogen generator including an air supply unit that supplies air and a burner that heats the reforming unit, a flow path that guides a product gas delivered from the hydrogen generator to the burner; Providing a reforming temperature detector for measuring the temperature, predicting the flammable gas flow rate in the generated gas based on the signal from the raw material supply unit and the signal from the reforming temperature detector, and supplying the gas from the air supply unit A hydrogen generator characterized by controlling the amount of air. 2. A shift unit filled with a shift catalyst installed downstream of the reforming unit, and a shift temperature detecting unit for measuring a temperature of the shift unit, wherein a signal from the raw material supply unit and the shift temperature 2. The method according to claim 1, wherein a flow rate of the flammable gas in the generated gas is predicted based on a signal from a temperature detection unit and a signal from the shift temperature detection unit, and an amount of air supplied from the air supply unit is controlled. The hydrogen generator as described in the above. 3. A purifying section, which is provided downstream of the shift section and is filled with a purifying catalyst, and a purifying temperature detecting section for measuring a temperature of the purifying section, wherein a signal from the raw material supply section and the reforming temperature are provided. A signal from the detection unit, a signal from the shift temperature detection unit, and a signal from the purification temperature detection unit predict a combustible gas flow rate in the generated gas, and control a supply air amount from the air supply unit. 3. The hydrogen generator according to claim 2, wherein: 4. A total flow rate of combustible gas in the burner is predicted from a predicted flow rate of combustible gas in the generated gas and a fuel flow rate based on a signal from the fuel supply section, 4. The hydrogen generator according to claim 1, wherein the amount of supplied air is controlled.