JP2002020103A - Method for starting and method for stopping hydrogen producing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for starting and a method for stopping a hydrogen producing device by which the operation cost or the installation area is reduced and dangerous works such as the exchange of nitrogen cylinder or hydrogen cylinder become unnecessary. SOLUTION: When starting, a combustion reaction occurs with hydrogen and air in a catalytic combustion part 14 and when the temperature of a steam reforming part 13 is raised and reaches the starting temperature, steam and a raw material hydrocarbon are supplied and a hydrogen-containing gas and air are supplied to a CO selective oxidation part 17. When stopping, the hydrogen-containing gas freed of CO from the CO selective oxidation part 17 is supplied to the catalytic combustion part 14 to be combusted, the supply of air to the CO selective oxidation part 17 is stopped to reduce the concentration of oxygen in the waste gas from the catalytic combustion part 14 and the waste gas is circulated in a reaction system to reduce the concentration of the inflammable gas and finally replaced with nitrogen, carbon dioxide or steam and the operation is stopped. As a result, the operation cost or the installation area is reduced and the works such as the exchange of nitrogen or hydrogen cylinder become unnecessary.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for starting and stopping a hydrogen production apparatus including a steam reforming section, or a hydrogen production apparatus used for a fuel cell system or other uses.

[0002]

2. Description of the Related Art A general hydrogen production apparatus is started and stopped by:
Use an inert gas such as nitrogen filled in a cylinder.
During startup, hydrogen is supplied from a hydrogen cylinder as a hydrogenation gas for heating and desulfurization using a burner while flowing nitrogen into the system from the cylinder. During shutdown, the temperature is reduced after replacing the combustible gas with nitrogen. With this method, oxidation of the catalyst can be prevented, and the operation can be performed safely. However, disadvantages of this method are that a nitrogen cylinder, a hydrogen cylinder, and the like are required, resulting in high costs and a large installation space. In addition, when the inert gas is exhausted, starting and stopping operations cannot be performed, and replacement of the cylinder is troublesome and high pressure, which is dangerous.
In addition, it is conceivable that a nitrogen cylinder or hydrogen cylinder cannot be installed due to a small device (for example, a hydrogen production device for home or on-vehicle fuel cells) and other circumstances, and furthermore, the infrastructure for hydrogen and nitrogen is not provided. There are also problems such as.

[0003] It is also conceivable that after the supply of the raw material hydrocarbons is stopped, the temperature is gradually lowered to such an extent that the catalyst is not oxidized, and then the air is replaced with air. However, according to this method, since air is supplied into the combustible gas, there is a concern that there is a danger. Further, although the use of a burner is generally used for heating the steam reforming section, there is a problem that the combustion stops when the combustible gas concentration decreases.

[0004]

SUMMARY OF THE INVENTION The present invention has been made on the background of the prior art, and does not require a cylinder such as a nitrogen cylinder or a hydrogen cylinder in a hydrogen production apparatus. A method for starting and stopping a hydrogen production apparatus, which can reduce the size of the apparatus because the installation space for the cylinder is not required, and can reduce the time required for replacing the cylinder which is troublesome and dangerous. It provides a method. In addition, the present invention relates to a home fuel cell and a vehicle fuel cell in which a cylinder cannot be installed, other fuel cells, an on-site hydrogen production device, and the like. Without using
It is an object of the present invention to provide a method of starting a safe hydrogen production apparatus and a method of stopping the same.

[0005]

According to a first aspect of the present invention, there is provided a desulfurizing section for removing a sulfur content of a raw hydrocarbon, and steam reforming by adding steam to the raw hydrocarbon desulfurized in the desulfurizing section. A steam reforming section that generates a hydrogen-containing gas by the above, a gas conversion section that converts carbon monoxide in the hydrogen-containing gas into carbon dioxide and hydrogen, and an air-converted hydrogen-containing gas in the gas conversion section. Is mixed to selectively convert carbon monoxide remaining in the hydrogen-containing gas into carbon dioxide and oxidize and remove the same, thereby producing a CO-removed hydrogen-containing gas.
The method for starting a hydrogen production apparatus, comprising: a catalytic oxidation unit for heating the steam reforming unit by causing a combustion reaction between an O selective oxidation unit and a combustible gas containing hydrogen and oxygen in air to heat the steam reforming unit. When the temperature of the steam reforming section is increased by supplying a CO-containing hydrogen-containing gas and air to the section to cause a catalytic combustion reaction, and the temperature of the steam reforming section reaches the steam reforming start temperature. , A method for starting a hydrogen production apparatus for starting supply of steam, raw material hydrocarbons.

According to a second aspect of the present invention, there is provided the method for starting a hydrogen production apparatus according to the first aspect, wherein the concentration of carbon monoxide in the CO-removed hydrogen-containing gas is set to 10 ppm or less.

According to a third aspect of the present invention, there is provided a method for starting a hydrogen production apparatus according to the first or second aspect, wherein the CO-removed hydrogen-containing gas is supplied to a fuel cell.

According to a fourth aspect of the present invention, the desulfurizing section comprises:
The hydrodesulfurization unit according to any one of claims 1 to 3, wherein the hydrodesulfurization unit is configured to desulfurize and remove sulfur in the raw material hydrocarbon after adding hydrogen for hydrodesulfurization to the raw material hydrocarbon. This is a method for starting the hydrogen production apparatus.

According to a fifth aspect of the present invention, there is provided any one of the first to fourth aspects of the present invention, further comprising a hydrogen storage unit for storing the CO-removed hydrogen-containing gas obtained from the CO selective oxidation unit. This is a method for starting the hydrogen production apparatus.

[0010] According to a sixth aspect of the present invention, there is provided a desulfurizing section for removing the sulfur content of the raw material hydrocarbon, and adding a steam to the raw material hydrocarbon desulfurized in the desulfurizing section to reform the hydrogen-containing gas by steam reforming. A steam reforming unit to be generated, a gas conversion unit that converts carbon monoxide in the hydrogen-containing gas into carbon dioxide and hydrogen, and air mixed with the gas-converted hydrogen-containing gas in the gas conversion unit A CO selective oxidizing unit for selectively converting carbon monoxide remaining in the contained gas to carbon dioxide and removing it by oxidation to produce a CO-removed hydrogen-containing gas, a hydrogen-containing combustible gas and oxygen in the air. A method for shutting down the hydrogen production apparatus comprising a catalytic combustion section for heating the steam reforming section by causing a combustion reaction,
O-removed hydrogen-containing gas is supplied directly to the catalytic combustion section,
The supply of air to the O selective oxidizing section is stopped, and the amount of air supplied to the catalytic combustion section is gradually reduced to reduce the oxygen concentration in the combustion gas discharged from the catalytic combustion section, thereby reducing the catalytic combustion. The combustion gas from the section is supplied into the reaction system of the hydrogen production device,
While gradually reducing the supply amounts of the raw material hydrocarbons and steam, the concentration of the combustible gas in the reaction system is reduced, and then the supply of air to the catalytic combustion section is stopped, and the temperature in the reaction system is reduced. This is a method for stopping the hydrogen production apparatus in which the above-mentioned hydrogen production apparatus is stopped after the temperature decreases.

The invention according to claim 7 is the method according to claim 6, wherein the hydrogen gas containing CO is supplied to a fuel cell.

[0012] In the invention described in claim 8, the desulfurization unit is configured to:
The method for stopping a hydrogen production apparatus according to claim 6 or 7, wherein the hydrogen desulfurization unit is configured to desulfurize and remove sulfur in the raw material hydrocarbon after adding hydrogen for the hydrodesulfurization to the raw material hydrocarbon. It is.

[0013]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a system diagram showing a starting method of a hydrogen production apparatus according to one embodiment of the present invention. FIG.
FIG. 3 is a system diagram showing a method for stopping the hydrogen production apparatus according to one embodiment of the present invention. In FIG. 1, reference numeral 10 denotes a hydrogen production apparatus using city gas, LPG, kerosene, methanol, or the like as a raw material. Here, city gas is used. Hereinafter, each component of the hydrogen production apparatus 10 will be described. Reference numeral 11 denotes a blower that supplies city gas (raw material hydrocarbon) to a hydrodesulfurization unit (desulfurization unit) 12. Note that a compressor may be used instead of the blower. The hydrodesulfurization unit 12 is divided into an upstream hydrogenation catalyst layer and a downstream desulfurization agent layer. In the hydrodesulfurization unit 12, by adding a part of the hydrogen-containing gas produced in the gas conversion unit 15 described later as hydrogen for hydrodesulfurization to the city gas supplied by the blower 11, the sulfur in the city gas is reduced. Minutes are desulfurized.
The CO-removed hydrogen-containing gas produced in the CO selective oxidizing section 17 may be used as hydrogen for hydrodesulfurization.

As the hydrogenation catalyst, NiM in which an oxide or sulfide such as nickel-molybdenum or cobalt-molybdenum is supported on a carrier such as silica or alumina is used.
ox catalyst or CoMox catalyst. Under low pressure, nickel-molybdenum catalysts are preferred. Also,
As the desulfurizing agent, zinc oxide, a nickel-based sorbent, or the like may be used alone or appropriately supported on a carrier. In the hydrogenation catalyst layer, sulfur in the raw hydrocarbon is hydrogenated to generate hydrogen sulfide. The reaction temperature is 300-400 ° C. In the desulfurizing agent layer, for example, H ₂ S + ZnO = ZnS +
The reaction of H ₂ O takes place. The raw hydrocarbon after desulfurization is supplied to the steam reforming section 13. Here, a method of hydrodesulfurizing a sulfur compound in a raw material hydrocarbon is employed, but a method of directly adsorbing a sulfur compound to a catalyst, for example, may also be used. Examples of the catalyst in this case include metals such as nickel, zinc, and copper, and oxides or sulfides thereof.
Furthermore, zeolite, activated carbon, etc. are mentioned. As the activated carbon, those impregnated with an alkali metal such as sodium, activated carbon adsorbing bromine, and the like can be used.

The steam reforming section 13 produces a high-concentration hydrogen-containing gas by adding water or steam to the desulfurized city gas and bringing the reformed catalyst into contact with the steam to reform the steam. The steam reforming section 13 is filled with a reforming catalyst in which an element such as ruthenium or nickel is supported on a carrier such as alumina or silica. Among these, a ruthenium-based catalyst is preferable when a raw material such as kerosene having a large number of carbon atoms is used, because carbon deposition can be suppressed. In the steam reforming section 13, steam reforming of the desulfurized hydrocarbon is performed. The reaction here is shown below.

Reference numeral 14 denotes a catalytic combustion section which is provided around the steam reforming section 13 and catalytically combusts hydrogen and oxygen in the air. Note that the catalytic combustion unit 14 is a steam reforming unit 1
3, and may be a heat exchange type reactor having high heat conductivity. As the catalyst of the catalytic combustion unit 14, a catalyst in which platinum, palladium, or the like is supported on alumina or the like is used. The temperature of the steam reforming unit 13 at the time of starting the hydrogen production device 10 is 380 ° C. or more, for example, 380 to 380 ° C.
500 ° C. If it is lower than 380 ° C., the reaction conversion rate is low,
Further, when a combustible gas containing hydrogen, methane, carbon monoxide and the like is reused in the catalytic combustion section, there is a disadvantage that the oxidation reaction of the combustible gas does not proceed. And finally, about 800 ° C. is preferable.

Reference numeral 15 denotes a gas conversion unit filled with a conversion catalyst for converting carbon monoxide in the high-concentration hydrogen-containing gas produced in the steam reforming unit 13 into carbon dioxide and hydrogen. As the shift catalyst, iron-chromium (for example, Fe ₂
O ₃ -Cr ₂ O ₃ catalyst) and, copper - copper-based catalyst is an oxide such as zinc is used. The reaction temperature was Fe ₂ O ₃ −
In the case of a Cr ₂ O ₃ catalyst, the temperature is preferably 300 to 450 ° C., and for the copper catalyst, the temperature is preferably 200 to 250 ° C. The reaction here is CO + H ₂ O = CO ₂ + H ₂ .

Reference numeral 17 denotes a hydrogen-containing gas from which gas has been converted in the gas conversion section 15 and water vapor has been removed by the KO drum 16, and air is mixed therewith to selectively remove carbon monoxide remaining in the high-concentration hydrogen-containing gas. Is converted to carbon dioxide and oxidized and removed.
This is a CO selective oxidizing unit for producing high-concentration hydrogen (CO-containing hydrogen-containing gas). Here, the CO selective oxidation method refers to CO
This is a method for selectively oxidizing and removing CO on a metal catalyst by adding an oxidizing agent such as air to a reformed gas containing hydrogen as a main component. The reactor is simple, and a catalyst in the form of a sphere or a pellet is packed in a reaction tube, or a catalyst carrying a honeycomb is used. The amount of oxygen to be supplied is C
0.5 to 4 times, preferably 1 to 2 times (molar ratio) the amount of O
Is generally supplied. Steam reformer 13
The reformed gas immediately after leaving the gas contains about 10% of carbon monoxide.
Reduce the concentration to the 10 ppm level. The reason for this is
This is because CO contained in high-concentration hydrogen supplied to a polymer electrolyte fuel cell (PEFC) 19 described later adsorbs on the electrode catalyst and blocks a hydrogen reaction site, thereby deteriorating cell performance.

As a catalyst of the CO selective oxidizing section 17, for example, platinum, ruthenium, palladium,
A catalyst supporting rhodium or the like is used. In the CO selective oxidation section 17, carbon monoxide is selectively adsorbed on these catalysts, and a small amount of air is added to convert carbon monoxide into carbon dioxide. The reaction temperature is 100 to 200 ° C. .

The reference numeral 16 denotes the CO selective oxidizing unit 1
The CO-removed hydrogen-containing gas obtained by oxidizing and removing CO in step 7 is cooled, and the water contained in the gas is condensed and removed.
O (knockout) drum.

Reference numeral 18 denotes a hydrogen storage tank (hydrogen storage unit) for storing high-concentration hydrogen (gas containing CO-removed hydrogen) purified in the CO selective oxidation unit 17. This high-concentration hydrogen (CO-removed hydrogen-containing gas) includes hydrogen, methane,
It contains carbon dioxide, etc., and the hydrogen concentration is 65% ~ 7
About 5%. The hydrogen storage tank 18 is capable of storing a necessary amount of hydrogen for catalytic combustion and hydrogenation gas at the time of startup, and is preferably a tank filled with a hydrogen storage alloy in order to achieve compactness.

Reference numeral 19 denotes a polymer electrolyte fuel cell (hereinafter referred to as a fuel cell 19) to which the CO-containing hydrogen-containing gas temporarily stored in the hydrogen storage tank 18 is supplied. As the use, for example, a home fuel cell, an in-vehicle fuel cell and the like can be mentioned. This fuel cell 19 has an electrolyte material. This electrolyte material generally has a polymer ion exchange membrane having a sulfonic acid group as an ion exchange group. When hydrogen (fuel) and oxygen (oxidant) are supplied to the cell, electric energy can be extracted to the outside by the following reaction.

H ₂ → 2H ⁺ + 2e ⁻ (1) 1 / 2O ₂ + 2H ⁺ + 2e ⁻ → H ₂ O (2) (All reactions) H ₂ + 1 / 2O ₂ → H ₂ O (3) According to the equation (1) The generated hydrogen ions move together with water (xH ₂ O) via ion exchange groups in the polymer ion exchange membrane, and react with oxygen as shown in formula (2) to form water (H ₂ O).
O). The air (oxygen) discharged from the oxygen side of the fuel cell 19 may be supplied to the catalytic combustion unit 14 and used as a supporting gas. The CO-removed hydrogen-containing gas whose CO concentration has been reduced to 10 ppm or less in the CO selective oxidizing section 17 is supplied to the fuel cell 19 after water content adjustment, where electric energy is obtained while generating water. The CO concentration in the CO-removed hydrogen-containing gas produced in the CO selective oxidizing section 17 is 10 ppm or less. Therefore, the possibility that the electrodes of the polymer electrolyte fuel cell 19 are poisoned by carbon monoxide and the cell performance is reduced is eliminated. The surplus CO-removed hydrogen-containing gas from the fuel cell 19 is supplied to the catalytic combustion unit 14 and burned.

The symbol E1 indicates that the blower 11 is
This is a heat exchanger that heat-exchanges the city gas supplied to 2 and the combustion gas from the catalytic combustion unit 14 to increase the city gas to a hydrodesulfurization temperature of 300 to 400 ° C. The symbol E2 represents water supplied to the steam reforming section 13 by the supply pump P,
The heat exchanger exchanges heat with the combustion gas from the catalytic combustion unit 14 to generate steam for steam reforming. Symbol E3
Is a gas (100 to 200 ° C.) from which CO is oxidized and removed by the CO selective oxidizing unit 17 and is supplied to the catalytic burning unit 14 by being selectively oxidized by the CO in the CO selective oxidizing unit 17 and bypassing the hydrogen storage tank 18 and the fuel cell 19 This is a heat exchanger for exchanging heat between the CO-removed hydrogen-containing gas and the surplus CO-removed hydrogen-containing gas supplied from the fuel cell 19 to the catalytic combustion unit 14. The combustible gas containing hydrogen, methane, carbon monoxide, etc., which is reused in the catalytic combustion unit 14 by the heat exchanger E3,
Heated to 380 ° C or higher and heated. Below 380 ° C,
This is because the oxidation reaction of a combustible gas such as methane is not performed smoothly.

The hydrogen production apparatus 10 includes a blower 11, a hydrodesulfurization unit 12, a steam reforming unit 13, a catalytic combustion unit 14, a gas conversion unit 15, a CO selective oxidizing unit 17, and a hydrogen storage tank 18. It is configured. However, when the hydrogen production apparatus 10 is a methanol fuel type PEFC system, the gas conversion section 15 is provided after the steam reforming section 13.
May not be provided. In the figure, reference numeral 20 denotes a four-way valve type flow path switching device (hereinafter, referred to as a four-way valve).

The method of starting and stopping the hydrogen production apparatus 10 having the above configuration will be described in detail below. First, FIG.
The operation at the time of startup will be described based on FIG. As shown in FIG. 1, the valve V10 is opened, and air outside the system is supplied to the catalytic combustion unit 14 via the four-way valve 20. Next, the valve V8 is opened and high-concentration hydrogen (CO-removed hydrogen-containing gas) is supplied from the hydrogen storage tank 18 filled with the hydrogen storage alloy to the four-way valve 20.
To the catalytic combustion unit 14 via In this way,
The supply of air and hydrogen causes a catalytic combustion reaction to take place in the catalytic combustion section 14. The combustion gas (exhaust gas) of the catalytic combustion unit 14 is heat-exchanged by the heat exchangers E1 and E2,
After that, it is discharged out of the system through the valve V14. When the combustion reaction in the catalytic combustion section 14 proceeds and the temperature (380 to 800 ° C.) of the steam reforming section 13 is stabilized, the valve V3 is opened, and the water pumped from the supply pump P is supplied to the heat exchanger E2.
Is converted into steam and supplied to the steam reforming section 13. Then, the valve V2 is opened and the hydrogen storage tank 18 is opened.
Further, hydrogen for hydrodesulfurization is supplied to the hydrodesulfurization unit 12, and similarly, V1 is opened to supply city gas (raw material hydrocarbon) to the hydrodesulfurization unit 12, and the blower 11 is started. This allows
Hydrogen desulfurization hydrogen from the hydrogen storage tank 18 is supplied to the blower 1
1 is added to the city gas supplied to the hydrodesulfurization unit 12. Thereafter, the city gas and the hydrogen for hydrodesulfurization are heat-exchanged by the heat exchanger E1, and heated and heated to 300 to 400 ° C.

Next, while gradually supplying the city gas to the hydrodesulfurization unit 12, the reforming reaction in the steam reforming unit 13 is started to produce a high-concentration hydrogen-containing gas. The high-concentration hydrogen-containing gas is supplied to the gas shift section 15, and carbon monoxide in the gas is converted into carbon dioxide and hydrogen by the shift catalyst. Further, the valve V9 is opened to supply the high-concentration hydrogen-containing gas and the air from which water has been removed to the CO selective oxidizing section 17, thereby starting the CO selective oxidizing reaction. The CO-removed hydrogen-containing gas is cooled by the heat exchanger E3, and the water contained in the gas is condensed and removed by the KO (knockout) drum 16. Thereafter, the valve V12 is opened, and the hydrogen is supplied to the catalytic combustor 14 through the heat exchanger E3 and the four-way valve 20 and burned until the hydrogen content of the CO-removed hydrogen-containing gas obtained in the CO selective oxidizing section 17 is stabilized. .

While stabilizing the reaction in the reaction system, the valves V4 and V5 are opened, and the valves V2 and V8 are closed. By opening the valve V5 and closing the valve V8, high-concentration hydrogen (CO-removed hydrogen-containing gas) with the CO concentration reduced to 10 ppm or less is supplied from the CO selective oxidizing section 17 to the hydrogen storage tank 18, and the valve V8 is opened. By closing the valve, the catalytic combustion unit 1 is removed from the hydrogen storage tank 18.
The supply of high-concentration hydrogen (CO-containing hydrogen-containing gas) toward 4 is stopped. Further, the valve V4 is opened, and the valve V2 is opened.
By closing the valve, the supply of hydrogen for desulfurization from the hydrogen storage tank 18 to the hydrodesulfurization unit 12 is stopped, and the high-concentration hydrogen-containing gas from which gas has been transformed and water has been removed is converted to hydrogen-desulfurized hydrogen. Is supplied to the hydrodesulfurization unit 12.
Then, the reaction in the hydrodesulfurization unit 12 and the steam reforming unit 13 is stabilized, and the purification of high-concentration hydrogen (CO-removed hydrogen-containing gas) in the CO selective oxidation unit 17 is stabilized. V7 and V11 are opened, and the valve V12 is closed.
Thus, the hydrogen storage tank 1 via the valve V6
From 8, high-concentration hydrogen (CO-removed hydrogen-containing gas) is supplied to the fuel cell 19. On the other hand, air outside the system is supplied to the fuel cell 19 via the valve V11. As a result, an ionic reaction occurs in the fuel cell 19, and electric energy can be extracted to the outside. Further, excess high-concentration hydrogen (CO-removed hydrogen-containing gas) is supplied from the fuel cell 19 to the catalytic combustion unit 14 through the heat exchanger E3 and the four-way valve 20 via the valve V7.

When the hydrogen production apparatus 10 is started, by adopting the catalytic combustion method as described above, high-concentration hydrogen (CO-containing hydrogen-containing gas) previously stored in the hydrogen storage tank 18 is supplied to the catalytic combustion section 14. By simply doing so, each reaction of hydrogen production in the system can be easily started. Similarly, hydrogen for hydrodesulfurization can be supplied from the hydrogen storage tank 18. This eliminates the need for a conventional hydrogen cylinder for desulfurization and a nitrogen cylinder for start-up. As a result, it is possible to obtain effects such as a reduction in the installation area of the cylinder and a reduction in the operation cost, and further, the need to replace the cylinder. Further, the CO concentration of the high-concentration hydrogen (CO-removed hydrogen-containing gas) produced in the CO selective oxidation section 17 is 1
Since it is 0 ppm or less, the influence of poisoning by the carbon monoxide of the electrode catalyst of the fuel cell 19 is reduced, and a decrease in cell performance can be prevented. The valve V15 in the figure is
It is always closed during this start-up and operation.

Next, the operation at the time of stop will be described with reference to FIG. As shown in FIG. 2, first, valves V6, V7, V
11 is closed, the supply of high-concentration hydrogen (CO-containing hydrogen-containing gas) from the hydrogen storage tank 18 to the fuel cell 19 and the supply of air from outside the system are stopped, and the ion reaction in the fuel cell 19 is stopped. Then, the valve V5 is closed, the valve V12 is opened, and the high-concentration hydrogen (CO-removed hydrogen-containing gas) from the CO selective oxidizing unit 17 is heated in the heat exchanger E3,
The fuel is supplied to the catalytic combustion section 14 through the way valve 20 and burned. Next, the valve V9 is closed, the supply of air to the CO selective oxidizing unit 17 is stopped, and the CO selective oxidizing reaction is stopped. Then, by adjusting the valve V10, the supply amount of air from outside the system is gradually reduced, and the oxygen concentration in the combustion gas from the catalytic combustion unit 14 is reduced to zero. At this time, in order to adjust the oxygen concentration of the combustion gas and to prevent a rapid temperature drop, the valve V8
If necessary, the valve V13 may be adjusted to supply high-concentration hydrogen (CO-containing hydrogen-containing gas) or city gas in the hydrogen storage tank 18 to the catalytic combustion unit 14 as auxiliary fuel. Such an adjustment of the oxygen concentration is necessary when the amount of air supplied to the catalytic combustion unit 14 is gradually reduced. For example, when the amount of air is insufficient, the oxygen This is to prevent oxygen from being mixed into the system such as the steam reforming unit 13 and a sharp drop in temperature. Subsequently, by adjusting the valve V1, the valve V15 is opened while gradually reducing the supply amount of the city gas, and the combustion gas from the catalytic combustion unit 14 is gradually supplied to the reaction system by the blower 11 and circulated. At this time, the exhaust of the combustion gas is stopped by closing the valve V14 which is the exhaust valve of the combustion gas.

The valves V2 and V4 and the valve V
3, the supply of hydrogen for desulfurization from the hydrogen storage tank 18 into the system and the supply of steam to the system by the supply pump P are gradually reduced while the hydrogen in the reaction system (hydrodesulfurization Unit 12, steam reforming unit 13, catalytic combustion unit 1
4. Reduce the flammable gas concentration in the gas conversion section 15 and the CO selective oxidation section 17). Finally, the supply of the city gas is stopped by completely closing the valve V1. Further, the valve V2
V3, V4 and, if necessary, valves V8, V13
To shut off the supply of steam, the supply of hydrogen for hydrodesulfurization, and the supply of auxiliary fuel to the catalytic combustion section.

Subsequently, the combustible gas in the system is completely replaced with nitrogen, carbon dioxide and water vapor, and the valve V10 is closed to stop the supply of air to the catalytic combustion unit 14. Further, when the temperature in the system (steam reforming section 13) drops to 100 ° C. or less, the blower 11 is stopped, and all operations are stopped. In addition, the temperature at the time of the stop is preferably lowered to room temperature because water in the system can be removed. When it is necessary to purge the gas in the system, the valve V14 is opened, and when the purge is completed, all the valves V1 to V1 are opened.
5 is closed. At this time, if all the valves V1 to V15 are closed while maintaining the pressure in the system, air does not flow into the system from outside during stoppage. As a result, oxidation of the catalyst can be prevented at the next start operation.

As described above, when the system of the hydrogen production apparatus 10 is stopped, the combustion gas (exhaust gas) containing no oxygen is recycled into the reaction system while gradually lowering the concentration of the flammable gas. Thereby, it is finally converted into nitrogen, carbon dioxide, and water vapor and stopped. As a result, the activity of each catalyst is reduced, especially in the case of ruthenium-based catalysts, etc., which prevents oxidation of catalysts that have problems such as high toxicity at high temperatures, and eliminates the need for replacement cylinders. Become. In addition, in this catalytic combustion method, the oxidation reaction can be performed even at a low concentration. Therefore, when the concentration of the flammable gas is gradually reduced during the stop operation, incomplete combustion can be prevented and the combustion reaction can be continued.

[0034]

According to the present invention, the hydrogen production apparatus can be started / stopped without using a nitrogen cylinder and a hydrogen cylinder, so that the operation cost and installation area can be reduced, and dangerous nitrogen and hydrogen cylinder replacement can be performed. The effect that work becomes unnecessary can be obtained. In addition, the start / stop operation can be automated by forming a sequence. Since the temperature of the steam reforming section is raised by the catalytic combustion method, it is possible to obtain effects such as downsizing of the apparatus and reduction of NOx.

Also, since the CO selective oxidation method is employed as the hydrogen purification section, it can be used at a relatively low temperature and at a normal pressure. Further, since high-concentration hydrogen (CO-removed hydrogen-containing gas) having a CO concentration of 10 ppm or less can be supplied to the polymer electrolyte fuel cell, the poisoning of the electrode catalyst by carbon monoxide is reduced, and the performance of the cell is prevented from being deteriorated. Can be. Further, it is possible to cope with a case where a cylinder cannot be placed in a hydrogen production apparatus for a vehicle-mounted or household fuel cell.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a starting method of a hydrogen production apparatus according to one embodiment of the present invention.

FIG. 2 is a system diagram showing a method for stopping the hydrogen production apparatus according to one embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 10 hydrogen production apparatus 11 blower 12 hydrodesulfurization section (desulfurization section) 13 steam reforming section 14 catalytic combustion section 15 gas conversion section 17 CO selective oxidation section 18 hydrogen storage tank (hydrogen storage section) 19 polymer electrolyte fuel cell ( Fuel cell)

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01M 8/04 H01M 8/04 J 8/06 8/06 G // H01M 8/10 8/10 F term (Reference) 4G040 EA03 EA06 EB03 EB31 EB43 4H060 AA01 BB08 BB11 BB12 CC13 FF02 GG02 5H026 AA06 5H027 AA06 BA01 BA13 BA14 BA16 BA17 KK42 MM12 MM13 MM14

Claims (8)

[Claims] 1. A desulfurization unit for removing a sulfur content of a raw hydrocarbon, a steam reforming unit for generating a hydrogen-containing gas by adding steam to the raw hydrocarbon desulfurized in the desulfurization unit and performing steam reforming. A gas conversion unit for converting carbon monoxide in the hydrogen-containing gas into carbon dioxide and hydrogen; and mixing air with the gas-converted hydrogen-containing gas in the gas conversion unit to remain in the hydrogen-containing gas. Selectively converting carbon monoxide to carbon dioxide for oxidative removal to produce a CO-removed hydrogen-containing gas, and combusting the hydrogen-containing flammable gas with oxygen in the air, In a method for starting a hydrogen production apparatus having a catalytic combustion section for heating a steam reforming section, the method comprises supplying a CO-containing hydrogen-containing gas and air to the catalytic combustion section to cause a catalytic combustion reaction, thereby causing the catalytic reforming reaction to occur. Temperature rise , When the temperature of the water vapor reforming unit has reached the starting temperature of the steam reforming, starting the hydrogen production apparatus starts supplying steam and hydrocarbon feedstock. 2. The method according to claim 1, wherein the concentration of carbon monoxide in said CO-removed hydrogen-containing gas is 10 ppm or less. 3. The method according to claim 1, wherein the CO-removed hydrogen-containing gas is supplied to a fuel cell. 4. The hydrodesulfurization unit according to claim 1, wherein the desulfurization unit is configured to add hydrogen for hydrodesulfurization to the raw material hydrocarbons, and then desulfurize and remove sulfur in the raw material hydrocarbons. 3
The method for starting a hydrogen production apparatus according to any one of the preceding claims. 5. A hydrogen storage unit for storing a CO-removed hydrogen-containing gas obtained from the CO selective oxidation unit.
The method for starting a hydrogen production apparatus according to claim 1. 6. A desulfurization unit for removing a sulfur content of a raw hydrocarbon, a steam reforming unit for generating a hydrogen-containing gas by adding steam to the raw hydrocarbon desulfurized in the desulfurization unit and performing steam reforming. A gas conversion unit that converts carbon monoxide in the hydrogen-containing gas into carbon dioxide and hydrogen; and mixing air with the hydrogen-containing gas that has been gas-converted in the gas conversion unit to form a gas remaining in the hydrogen-containing gas. A CO selective oxidizing unit for selectively converting carbon oxide to carbon dioxide to produce a CO-removed hydrogen-containing gas, and a combustion reaction between a hydrogen-containing flammable gas and oxygen in the air to form the steam reforming unit In the method for stopping a hydrogen production apparatus having a catalytic combustion unit to be heated, the CO-containing hydrogen-containing gas from the CO selective oxidation unit is supplied directly to the catalytic combustion unit, and the supply of air to the CO selective oxidation unit is stopped. And the above catalyst fuel The amount of air supplied to the catalytic combustion section is gradually reduced to reduce the oxygen concentration in the combustion gas discharged from the catalytic combustion section, and the combustion gas from the catalytic combustion section is supplied into the reaction system of the hydrogen production device. The concentration of combustible gas in the reaction system is reduced while gradually reducing the supply amounts of the raw material hydrocarbon and steam, and thereafter, the supply of air to the catalytic combustion section is stopped, and the A method for stopping the hydrogen production device, wherein the hydrogen production device is stopped after the temperature has dropped. 7. The method according to claim 6, wherein the CO-containing hydrogen-containing gas is supplied to a fuel cell. 8. The hydrodesulfurization unit according to claim 6, wherein the desulfurization unit is configured to add hydrogen for hydrodesulfurization to the raw material hydrocarbon, and then desulfurize and remove sulfur in the raw material hydrocarbon. 8. The method for stopping the hydrogen production apparatus according to 7.