JP7108832B2 - Hydrogen generator, fuel cell system using the same, and method of operating the same - Google Patents

Description

The present invention provides a hydrogen generator equipped with a CO remover that reduces the concentration of carbon monoxide contained in hydrogen-containing gas discharged from a reformer by an oxidation reaction, a fuel cell system using the same, and its The present invention relates to a method of operating a hydrogen generator.

Many fuel cells, for example polymer electrolyte fuel cells, use hydrogen as fuel during power generation operation. However, the hydrogen supply means required for the power generation operation of these fuel cells has not yet been developed as an infrastructure.

Therefore, in order to obtain electric power from a fuel cell system including a polymer electrolyte fuel cell, it is necessary to generate hydrogen as fuel at the location where the fuel cell system is installed.

Therefore, in conventional fuel cell systems, a hydrogen generator is often installed together with the fuel cell. This hydrogen generator includes, for example, a reformer that generates a hydrogen-containing gas by a steam reforming reaction.

In this steam reforming reaction, a hydrocarbon-based raw material (raw material gas) such as natural gas, propane gas, naphtha, gasoline, or kerosene, or an alcohol-based raw material such as methanol is used. The raw material is supplied together with water to a reformer equipped with a reforming catalyst, and a steam reforming reaction proceeds to generate a hydrogen-containing gas.

On the other hand, the hydrogen-containing gas produced in the reformer by the steam reforming reaction contains carbon monoxide (CO) produced as a by-product. For example, the hydrogen-containing gas produced in the reformer of the hydrogen generator contains carbon monoxide at a concentration of about 10-15%.

Here, the carbon monoxide contained in the hydrogen-containing gas significantly poisons the electrode catalyst of the polymer electrolyte fuel cell. This poisoning of the electrode catalyst significantly reduces the power generation performance of the polymer electrolyte fuel cell.

Therefore, in the conventional hydrogen generator, in addition to the reformer that generates hydrogen-containing gas, a CO remover equipped with an oxidation catalyst is provided in order to sufficiently reduce the carbon monoxide concentration in the hydrogen-containing gas. There are many things.

This CO remover reduces the concentration of carbon monoxide in the hydrogen-containing gas produced by the reformer to 100 ppm or less, preferably 10 ppm or less. This hydrogen-containing gas from which carbon monoxide has been sufficiently removed is supplied to the fuel cell of the fuel cell system during power generation operation. This prevents poisoning of the electrode catalyst in the polymer electrolyte fuel cell.

In order to perform the steam reforming reaction stably and efficiently, it is necessary to supply an amount of water suitable for the composition of the feedstock. For example, in the steam reforming reaction of hydrocarbons shown in Chemical Formula 1, theoretically, the amount of water required for 1 mol of methane (CH ₄ ) is 2 mol. Also, the amount of water required is 4 moles for 1 mole of ethane (C ₂ H ₆ ).

On the other hand, simultaneously with the steam reforming reaction, the reverse shift reaction shown in (Chem. 2) proceeds, and carbon monoxide and water are produced from the hydrogen and carbon dioxide produced in the steam reforming reaction.

This reaction consumes the hydrogen produced from the hydrocarbon and reduces the amount of hydrogen in the hydrogen-containing gas. Therefore, in order to efficiently generate the hydrogen-containing gas supplied to the fuel cell by the steam reforming reaction, the steam reforming reaction (Chem. 1) is promoted and the reverse shift reaction (Chem. 2) is suppressed. Therefore, it is preferable to increase the amount of water supplied to the reformer more than the theoretical amount of water supplied.

Further, by increasing the amount of water supplied to the reformer to a theoretical amount, it is possible to suppress problems such as carbon deposition on the reforming catalyst. Therefore, the ratio of the number of carbon atoms in the hydrocarbon in the raw material to the number of water atoms in the water supplied to the reformer (hereinafter referred to as S/C) is usually the theoretical water It is set so that about 1.5 times the amount of water supplied to the reformer is supplied to the reformer.

By the way, natural gas, which is the main raw material used in the reformer of the hydrogen generator, usually contains nitrogen, which is a type of nitrogen compound. This nitrogen content varies, for example, depending on the region to which natural gas is supplied. Then, when the natural gas containing nitrogen is supplied to the reformer of the hydrogen generator during the power generation operation of the fuel cell system, the hydrogen generated on the reforming catalyst reacts with the nitrogen in the natural gas. and ammonia may be produced.

If ammonia is contained in the hydrogen-containing gas, the catalyst of the fuel cell is poisoned by the ammonia, making it impossible to generate electricity. Therefore, in the hydrogen generator that supplies the hydrogen-containing gas to the fuel cell, it is necessary to decompose the ammonia in the hydrogen-containing gas and reduce the ammonia concentration in the hydrogen-containing gas to a concentration suitable for supply to the fuel cell. .

By the way, among the oxidation catalysts provided in the CO remover, those in which ruthenium or platinum is supported on alumina are known to be capable of decomposing carbon monoxide and ammonia.

However, in general, in a CO remover provided in a hydrogen generator that generates a hydrogen-containing gas by a steam reforming reaction, the ammonia decomposition activity rapidly decreases. is supplied to the fuel cell.

The mechanism is assumed as follows. First, the chemical reaction represented by the reaction formula (Chem. 3) between the oxidizing gas and the ammonia contained in the hydrogen-containing gas proceeds on the oxidation catalyst to produce nitrosyl (NO).

The generated nitrosyl is strongly adsorbed on the surface of the oxidation catalyst, and in order to remove it, the nitrosyl is decomposed into nitrogen and desorbed by the nitrosyl reduction reaction shown in (Chem. 4) or (Chem. 5). I can think of a way to make it work.

However, the CO remover is supplied with an oxidizing gas to oxidize the carbon monoxide. Under the conditions in which the oxidizing gas is supplied, the above reduction reaction is difficult to proceed, and the nitrosyl quickly forms on the surface of the oxidation catalyst. and the ammonia decomposition activity decreases. Therefore, the hydrogen-containing gas containing ammonia is supplied from the CO remover to the fuel cell.

Therefore, in order to reduce the concentration of ammonia in the hydrogen-containing gas to a concentration suitable for supply to the fuel cell, an ammonia remover is provided between the reformer and the CO remover, and the ammonia discharged from the reformer is A configuration has been proposed in which ammonia in a hydrogen-containing gas is absorbed by water to remove it (see, for example, Patent Document 1).

JP 2012-46395 A

However, in the above conventional configuration, in order to generate a hydrogen-containing gas with a reduced ammonia concentration, it is necessary to separately provide an ammonia remover, which increases equipment costs and increases the size of the hydrogen generator. .

The present invention solves the conventional problems described above, and by promoting the ammonia decomposition reaction of the oxidation catalyst of the CO remover, hydrogen-containing gas with a reduced ammonia concentration is generated without providing an ammonia remover separately. It is an object of the present invention to provide a hydrogen generator capable of reducing equipment costs and a fuel cell system using the same.

In order to solve the conventional problems, the hydrogen generator of the present invention includes a reformer that reforms a raw material containing hydrocarbons as a main component to generate a hydrogen-containing gas, and a reformer that generates a hydrogen-containing gas. a CO remover equipped with an oxidation catalyst capable of reducing the concentration of carbon by an oxidation reaction and decomposing ammonia; a raw material supplier supplying raw materials to the reformer; and a water supplier supplying water to the reformer; an oxidizing gas supplier for supplying an oxidizing gas to the CO remover; and a controller, wherein the feedstock includes a nitrogen compound, and the controller adjusts to parameters relating to the concentration of ammonia in the hydrogen-containing gas supplied to the CO remover. Accordingly, S/C, which is the ratio of the number of carbon atoms in the hydrocarbons in the raw material to the number of water molecules in the water supplied to the reformer, is set to a water supply device to change the water vapor partial pressure in the hydrogen-containing gas supplied from the reformer to the CO remover to a value within a range of a first set value or less, which is the S/C of and a raw material feeder.

As a result, the S / C is changed to a value within the range of the first set value or less so as to reduce the water vapor partial pressure in the hydrogen-containing gas supplied from the reformer to the CO remover, thereby reforming The water vapor partial pressure in the hydrogen-containing gas supplied from the reactor to the CO remover is lower than when the S/C is set to the first set value, and the amount of water vapor adsorption on the oxidation catalyst surface is reduced.

In addition, since water vapor and carbon monoxide compete with each other for adsorption on the oxidation catalyst surface, the amount of water vapor adsorption on the oxidation catalyst surface decreases, thereby increasing the adsorption amounts of carbon monoxide and hydrogen. At this time, the nitrosyl reduction reaction shown in (Chem. 4) or (Chem. 5) proceeds on the surface of the oxidation catalyst following the formation reaction of nitrosyl shown in (Chem. 3).

(Chem. 4) and (Chem. 5) are equilibrium reactions. In (Chem. 4), the adsorption amount of the product water vapor decreases, and in (Chem. 5), the adsorption amount of the reactant carbon monoxide increases. As a result, the reactions of both (4) and (5) proceed to the right side, promoting the decomposition of nitrosyl.

By decomposing the nitrosyl adsorbed on the surface of the oxidation catalyst in this way, the ammonia decomposition activity of the oxidation catalyst is improved, and the ammonia concentration in the hydrogen-containing gas can be reduced without providing an ammonia remover, thereby reducing the equipment cost. can be reduced.

Also, a fuel cell system of the present invention includes the hydrogen generator of the present invention and a fuel cell that generates power using the hydrogen-containing gas supplied from the hydrogen generator.

As a result, even if power is generated using raw materials containing nitrogen compounds, deterioration of the fuel cell can be suppressed without providing an ammonia remover, and a fuel cell system capable of reducing equipment costs can be provided.

According to the hydrogen generator of the present invention, hydrogen-containing gas with a sufficiently reduced ammonia concentration can be supplied without an ammonia remover, so the hydrogen generator can be made smaller and less expensive. .

In addition, according to the fuel cell system of the present invention, power generation can be performed using a hydrogen-containing gas with a sufficiently reduced ammonia concentration without an ammonia remover, and miniaturization and cost reduction are possible. It is possible to provide a long-life fuel cell system in which ammonia poisoning of the fuel cell is suppressed.

FIG. 1 is a block diagram showing the configuration of a hydrogen generator according to Embodiment 1 of the present invention; Flowchart showing the operation of the hydrogen generator in Embodiment 1 of the present invention A characteristic diagram showing the relationship between the S/C and the ammonia decomposition rate of the CO remover in Embodiment 1 of the present invention. FIG. 2 is a block diagram showing the configuration of a fuel cell system according to Embodiment 2 of the present invention; Flowchart showing the first part of the operation of the fuel cell system according to Embodiment 2 of the present invention Flowchart showing the latter part of the operation of the fuel cell system according to Embodiment 2 of the present invention A characteristic diagram showing the relationship between the nitrogen concentration in natural gas, the ammonia concentration in the CO remover outlet gas, and the amount of hydrogen in Embodiment 2 of the present invention.

A first invention is a reformer that reforms a raw material containing hydrocarbons as a main component to generate a hydrogen-containing gas, and a reformer that reduces the concentration of carbon monoxide contained in the hydrogen-containing gas by an oxidation reaction and reduces the concentration of ammonia a CO remover equipped with an oxidation catalyst capable of decomposing CO, a raw material supplier for supplying raw materials to the reformer, a water supplier for supplying water to the reformer, and an oxidizing gas for supplying oxidizing gas to the CO remover and a controller, wherein the feedstock comprises nitrogen compounds, the controller controlling the amount of hydrocarbon carbon atoms in the feedstock in response to a parameter relating to the concentration of ammonia in the hydrogen-containing gas fed to the CO remover. S/C, which is the ratio of the number of water molecules to the number of water molecules in the water supplied to the reformer, is equal to or less than the first set value, which is the S/C during operation when the raw material does not contain nitrogen compounds. The water feeder and the raw material feeder are controlled so as to change the water vapor partial pressure in the hydrogen-containing gas supplied from the reformer to the CO remover to a value within the range of It is a hydrogen generator that

As a result, the S / C is changed to a value within the range of the first set value or less so as to reduce the water vapor partial pressure in the hydrogen-containing gas supplied from the reformer to the CO remover, thereby reforming The water vapor partial pressure in the hydrogen-containing gas supplied from the reactor to the CO remover is lower than when the S/C is set to the first set value, and the amount of water vapor adsorption on the oxidation catalyst surface is reduced.

In addition, since water vapor and carbon monoxide compete with each other for adsorption on the oxidation catalyst surface, the amount of water vapor adsorption on the oxidation catalyst surface decreases, thereby increasing the adsorption amounts of carbon monoxide and hydrogen. At this time, the nitrosyl reduction reaction shown in (Chem. 4) or (Chem. 5) proceeds on the surface of the oxidation catalyst following the formation reaction of nitrosyl shown in (Chem. 3).

(Chem. 4) and (Chem. 5) are equilibrium reactions. In (Chem. 4), the adsorption amount of the product water vapor decreases, and in (Chem. 5), the adsorption amount of the reactant carbon monoxide increases. As a result, the reactions of both (4) and (5) proceed to the right side, promoting the decomposition of nitrosyl.

By decomposing the nitrosyl adsorbed on the surface of the oxidation catalyst in this way, the ammonia decomposition activity of the oxidation catalyst is improved, and the ammonia concentration in the hydrogen-containing gas can be reduced without providing an ammonia remover, thereby reducing equipment costs. can be reduced.

In the second invention, particularly, the controller in the first invention sets the S/C to the first set value when the parameter is less than the predetermined threshold, and sets the S/C to the first set value when the parameter is greater than or equal to the predetermined threshold. , and S/C at a second set value less than the first set value.

As a result, operation can be performed without changing the S/C until the parameter exceeds the predetermined threshold value. For this reason, it is possible to supply a hydrogen-containing gas with a sufficiently reduced ammonia concentration while suppressing a decrease in the amount of hydrogen-containing gas produced by changing the S/C to a low value and suppressing carbon deposition on the reforming catalyst. It becomes possible.

The third invention is particularly characterized in that the parameters in the first or second invention are determined based on information related to the concentration of nitrogen compounds in the raw material.

As a result, the concentration of ammonia in the hydrogen-containing gas supplied to the CO remover can be calculated from information related to the concentration of nitrogen compounds in the raw material, and an appropriate S/ It is possible to change to C. Therefore, it is possible to supply a hydrogen-containing gas with a sufficiently reduced ammonia concentration while reducing the amount of hydrogen-containing gas produced and suppressing carbon deposition on the reforming catalyst.

A fourth aspect of the invention is characterized by further comprising an information acquirer for acquiring the information according to the third aspect of the invention.

This makes it possible to more accurately determine the concentration of nitrogen compounds in the raw material, so CO
It is possible to change the S/C to an appropriate one according to the ammonia concentration in the hydrogen-containing gas supplied to the remover, thereby improving the ammonia decomposition activity. Therefore, it is possible to supply a hydrogen-containing gas with a sufficiently reduced ammonia concentration while reducing the amount of hydrogen-containing gas produced and suppressing carbon deposition on the reforming catalyst.

In a fifth aspect of the invention, particularly, the information in the third or fourth aspect includes information on the concentration of nitrogen compounds, information on the type of raw material, information on the location of the hydrogen generator , and information on the main supplier of the raw material. It is characterized by being either.

This makes it possible to accurately grasp the concentration of nitrogen compounds in the raw material regardless of the area where the hydrogen generator is installed and the supplier of the raw material.

Therefore, the ammonia decomposition activity of the oxidation catalyst can be improved according to the concentration of the nitrogen compound in the raw material, and the hydrogen-containing gas with sufficiently reduced ammonia concentration can be more reliably supplied.

A sixth invention is particularly characterized in that the controller in any one of the first to fifth inventions controls the raw material feeder so as to change the raw material supply amount when changing the S/C. It is something to do.

As a result, while suppressing changes in the amount of hydrogen-containing gas produced in the reformer, which fluctuates according to changes in S/C, the concentration of ammonia in the hydrogen-containing gas is adjusted to a concentration suitable for supplying to the fuel cell. can be reduced to

In a seventh invention, in particular, in any one of the first to sixth inventions, further comprising a heater for heating the reformer, wherein the controller changes the S/C to a value equal to or less than the first set value characterized by controlling the heater so as to raise the temperature of the reformer to a temperature higher than the first set value, which is the temperature of the reformer when the raw material does not contain a nitrogen compound, when the raw material contains no nitrogen compound. It is something to do.

As a result, by promoting the steam reforming reaction in the reformer, the amount of hydrogen in the hydrogen-containing gas in the reformer increases, and the hydrogen-containing gas supplied from the reformer to the CO remover can further reduce the water vapor partial pressure of As a result, it is possible to further improve the ammonia decomposition activity of the oxidation catalyst while suppressing a decrease in the amount of hydrogen produced, and to supply a hydrogen-containing gas with a sufficiently reduced ammonia concentration.

An eighth invention is a fuel cell system comprising, in particular, the hydrogen generator of any one of the first to seventh inventions and a fuel cell that generates electricity using the hydrogen-containing gas supplied from the hydrogen generator. be.

As a result, even if power is generated using a raw material containing a nitrogen compound, it is possible to generate power using a hydrogen-containing gas with a sufficiently reduced ammonia concentration, so deterioration of the fuel cell can be suppressed. It is possible to extend the life of the fuel cell system.

A ninth invention is a reformer for reforming a raw material containing hydrocarbons as a main component to produce a hydrogen-containing gas, and a reformer for reducing the concentration of carbon monoxide contained in the hydrogen-containing gas by an oxidation reaction and reducing ammonia a CO remover equipped with an oxidation catalyst capable of decomposing CO, a raw material supplier for supplying raw materials to the reformer, a water supplier for supplying water to the reformer, and an oxidizing gas for supplying oxidizing gas to the CO remover a feeder, wherein the feed comprises nitrogen compounds, and depending on a parameter relating to the concentration of ammonia in the hydrogen-containing gas fed to the CO remover, carbon of the hydrocarbons in the feed. S/C, which is the ratio of the number of atoms to the number of water molecules in the water supplied to the reformer, is a value within the range below the S/C during operation when the raw material does not contain nitrogen compounds. A method of operating a hydrogen generator, characterized in that the water vapor partial pressure in the hydrogen-containing gas supplied from the reformer to the CO remover is changed so as to be lowered .

As a result, the partial pressure of water vapor in the hydrogen-containing gas supplied from the reformer to the CO remover decreases, and the amount of water vapor adsorbed on the surface of the oxidation catalyst decreases. In addition, since water vapor and carbon monoxide compete with each other for adsorption on the surface of the oxidation catalyst, the adsorption amount of carbon monoxide and hydrogen increases as the amount of water vapor adsorption on the surface of the oxidation catalyst decreases. At this time, the nitrosyl reduction reaction shown in (Chem. 4) or (Chem. 5) proceeds on the surface of the oxidation catalyst following the formation reaction of nitrosyl shown in (Chem. 3).

(Chem. 4) and (Chem. 5) are equilibrium reactions. In (Chem. 4), the adsorption amount of the product water vapor decreases, and in (Chem. 5), the adsorption amount of the reactant carbon monoxide increases. As a result, the reactions of both (4) and (5) proceed to the right side, promoting the decomposition of nitrosyl.

By decomposing the nitrosyl adsorbed on the surface of the oxidation catalyst in this way, the ammonia decomposition activity of the oxidation catalyst is improved, and the ammonia concentration in the hydrogen-containing gas can be reduced without providing an ammonia remover, thereby reducing equipment costs. can be reduced.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the present invention is not limited by this embodiment.

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

As shown in FIG. 1, the hydrogen generator 350 of the present embodiment uses natural gas containing nitrogen, which is a type of nitrogen compound, as a raw material and fuel gas, and air as an oxidizing gas to produce a hydrogen-containing gas. A hydrogen generator 350 that generates hydrogen, comprising a reformer 100 that reforms natural gas to generate a hydrogen-containing gas, a reformer temperature detector 50 that detects the temperature of the reformer 100, and a reformer a raw material supplier 20 that supplies natural gas to 100; an evaporator 31 that evaporates water and supplies steam to the reformer 100; a water supplier 30 that supplies water to the evaporator 31; A CO remover 150 that reduces the concentration of carbon monoxide contained in the hydrogen-containing gas produced by an oxidation reaction, an oxidizing gas supplier 40 that supplies air to the CO remover 150, and a CO remover 150 to the outside. A hydrogen-containing gas supply channel 60 that supplies hydrogen-containing gas, a heater 10 that heats the reformer 100, a fuel gas supply channel 70 that supplies natural gas to the heater 10, an information input device 310, and a controller 300 that controls the hydrogen generator 350 .

The reformer 100 generates a hydrogen-containing gas through a reforming reaction from a mixed gas of natural gas and steam. The reformer 100 is made of a stainless steel structure, and is filled with a reforming catalyst that advances the reforming reaction.

In this embodiment, the reforming catalyst used is a reforming catalyst in which ruthenium is carried by using alumina beads as a carrier. The reforming reaction in the reformer 100 requires reaction heat of 550° C. to 660° C. In the present embodiment, the heat transferred from the heater 10 arranged adjacent to the reformer 100 is used to heat the reformer. 100 reforming catalysts are heated from 550°C to 660°C.

The evaporator 31 evaporates water supplied from the water supply device 30 and supplies steam to the reformer 100 .

The reformer temperature detector 50 detects the temperature of the reformer 100. Here, a thermocouple installed in a sheath pipe provided inside the reformer 100 is used to directly measure the catalyst temperature. do.

The raw material supplier 20 supplies natural gas as a raw material to the reformer 100, and here, a pump capable of adjusting the flow rate is used.

The water supply device 30 supplies water to the evaporator 31, and here, a pump capable of adjusting the flow rate is used.

The CO remover 150 is necessary for a hydrogen utilization device (not shown) connected to the outside of the hydrogen generator 350 to utilize the concentration of carbon monoxide in the hydrogen-containing gas discharged from the reformer 100. concentration, for example, 10 ppm or less, by an oxidation reaction, and an oxidation catalyst is filled inside. Here, as the oxidation catalyst, ruthenium supported by alumina beads is used.

The oxidizing gas supplier 40 is a fan that supplies air as an oxidizing gas to the CO remover 150 .

The hydrogen-containing gas supply channel 60 is a channel for supplying the hydrogen-containing gas, the concentration of carbon monoxide of which has been reduced by the CO remover 150 , to the outside of the hydrogen generator 350 .

The fuel gas supply channel 70 is a channel for supplying natural gas as fuel gas to the heater 10 .

The heater 10 heats the reformer 100, and is a combustor that uses the natural gas supplied from the fuel gas supply passage 70 as fuel.

The information input device 310 is for inputting information necessary to determine the parameters regarding the ammonia concentration in the hydrogen-containing gas supplied to the CO remover 150 and is electrically connected to the controller 300 . Here, it is a DIP switch for inputting the supply main of natural gas to be supplied to the hydrogen generator 350 .

The controller 300 controls the operation of the hydrogen generator 350, and includes a signal input/output unit (not shown), an arithmetic processing unit (not shown), and a storage unit (not shown) for storing control programs. (not shown).

The operation and action of the hydrogen generator 350 of the present embodiment configured as described above will be described.

The following operations are performed by the controller 300 controlling the heater 10 , the raw material supplier 20 , the water supplier 30 and the oxidizing gas supplier 40 . Here, the water supplier 30 supplies the necessary amount of water, which is determined by the S/C set value and the amount of natural gas supplied from the raw material supplier 20, to the reformer 100 via the evaporator 31. do.

Here, S/C is the ratio between the number of carbon atoms in the hydrocarbons in the natural gas supplied to the reformer 100 and the number of water molecules in the steam supplied to the reformer 100 .

In addition, the oxidizing gas supplier 40 controls the temperature of the reformer 100 detected by the reformer temperature detector 50, the set value of the S/C, and the amount of natural gas supplied from the raw material supplier 20. It is set to supply a sufficient amount of air for the calculated carbon monoxide concentration in the hydrogen-containing gas supplied to the CO remover 150 .

FIG. 2 is a flow chart showing the operation of the hydrogen generator 350 according to the first embodiment.

As shown in FIG. 2, the controller 300 first determines whether there is a request to start the operation of the hydrogen generator 350 (S11).

At this time, if there is a request to start the operation of the hydrogen generator 350, the controller 300 controls the heater 10 to burn the natural gas supplied to the heater 10 via the fuel gas supply path 70. An operation is performed to heat the reformer 100 (S12). Thereby, the reformer 100 is heated by the heater 10 to 660° C., which is a temperature suitable for the steam reforming reaction.

In (S11), if there is no request to start operation of the hydrogen generator 350, the controller 300 continues to check whether there is a request to start operation of the hydrogen generator 350 until there is a request to start operation of the hydrogen generator 350. Repeat the judgment.

Next, the controller 300 determines whether or not the temperature of the reformer 100 detected by the reformer temperature detector 50 has reached 660° C. (S13).

At this time, if the temperature of the reformer 100 detected by the reformer temperature detector 50 has reached 660° C., the raw material supplier 20, the water supplier 30, and the oxidizing gas supplier 40 are all supplied. (S14).

In (S13), if the temperature of the reformer 100 detected by the reformer temperature detector 50 has not reached 660° C., the temperature of the reformer 100 detected by the reformer temperature detector 50 is Until reaching 660°C, the controller 300 repeatedly determines whether the temperature of the reformer 100 detected by the reformer temperature detector 50 has reached 660°C.

Next, the S/C set value, the amount of water supplied from the water supplier 30, and the amount of air supplied from the oxidant gas supplier 40 are determined from the information input to the information input device 310 (S15).

In the present embodiment, the storage unit of the controller 300 stores the nitrogen concentration in the natural gas supplied by the supplier of the natural gas supplied to the hydrogen generator 350 and the nitrogen concentration in the supplied natural gas. , the ammonia concentration in the hydrogen-containing gas produced by the reformer 100 is stored.

Here, the method of determining the S/C set value will be described by taking as an example the case where the average nitrogen concentration in the natural gas supplied from the natural gas supplier input from the information input device 310 is 15%. .

In the present embodiment, the natural gas supply rate from the raw material supplier 20 is 3.0 L/min, the nitrogen concentration in the natural gas is 15% on average, and the reformer temperature detector 50 detects The temperature of the qualityr 100 is 660°C.

Under these conditions, the concentration of ammonia in the hydrogen-containing gas supplied to the CO remover 150 is experimentally determined in advance and is 6 ppm, which is stored in the storage section of the controller 300 . Also, the target value of the concentration of ammonia in the hydrogen-containing gas discharged from the CO remover 150 is assumed to be 1 ppm.

Based on the above conditions, S/C is set. The setting of the S/C is determined based on the relationship between the S/C and the ammonia decomposition rate of the CO remover 150 so that the ammonia concentration in the hydrogen-containing gas can be reduced to the target concentration.

FIG. 3 is a characteristic diagram showing the relationship between the S/C in the hydrogen generator 350 of Embodiment 1 and the ammonia decomposition rate of the CO remover 150. As shown in FIG.

As shown in FIG. 3, the S/C in the present embodiment and the ammonia decomposition rate of the CO remover 150 are in a relationship such that the ammonia decomposition rate of the CO remover 150 improves as the S/C decreases. be. Based on this relationship, the set value of S/C is calculated by the following (Equation 1).

Here, a is the set value of S/C, b is the target value (ppm) of the ammonia concentration in the hydrogen-containing gas at the outlet of the CO remover 150, and c is ammonia in the hydrogen-containing gas supplied to the CO remover 150. concentration (ppm).

In the present embodiment, as described above, b is 1 ppm and c is 6 ppm, so these values are substituted into (Equation 1) to obtain the S/C set value a, and the S/C set value a is determined to be 2.5.

The water supply rate from the water supply device 30 is 3.0 L/min for the natural gas supply rate from the raw material supply device 20 as described above, the S/C is 2.5, and the nitrogen concentration in the natural gas is Since it is 15%, the water supply rate from the water supply device 30 is determined to be 5.12 mL/min based on the number of carbon atoms in the hydrocarbons in the natural gas.

Also, the amount of air supplied from the oxidizing gas supplier 40 is set based on the temperature of the reformer 100 and the theoretical value of the carbon monoxide concentration in the hydrogen-containing gas calculated from the S/C. In this embodiment, the air supply rate is set to 0.85 L/min so as to supply twice as many oxygen molecules as the number of carbon monoxide molecules contained in the hydrogen-containing gas.

Next, the supply amounts of the material supplier 20, the water supplier 30, and the oxidizing gas supplier 40 are adjusted to the values determined in (S15), thereby starting hydrogen-containing gas generation (S16).

The reformer 100 generates a hydrogen-containing gas by a steam reforming reaction from the natural gas and water (steam) supplied to the reformer 100 . On the other hand, the hydrogen-containing gas produced by the reformer 100 contains ammonia produced from nitrogen contained in natural gas.

The generated hydrogen-containing gas flows into the CO remover 150, and carbon monoxide is oxidized by an oxidation reaction with oxygen in the air supplied from the oxidizing gas supplier 40 on the oxidation catalyst in the CO remover 150. be.

Ammonia is then oxidized to nitrosyl by the oxygen in the air and then reduced to nitrogen by hydrogen or carbon monoxide in the hydrogen-containing gas. The hydrogen-containing gas in which ammonia is sufficiently reduced is supplied to the outside of the hydrogen generator 350 via the hydrogen-containing gas supply channel 60 .

After (S16), the controller 300 determines whether there is a request to stop the operation of the hydrogen generator 350 (S17). At this time, if there is a request to stop the operation of the hydrogen generator 350 , the controller 300 stops the operation of the hydrogen generator 350 . On the other hand, in (S17), if a request to stop the operation of the hydrogen generator 350 is not generated, the determination operation of (S17) is repeated until a request to stop the operation of the hydrogen generator 350 is generated.

The S/C is set based on the information input to the information input device 310 as described above, and the hydrogen generator 350 is operated. The concentration of ammonia in the hydrogen-containing gas is 0.87 ppm.

In the hydrogen generator 350 of the present embodiment, the first set value of S/C when nitrogen is not contained is 3.2. When the S/C is 3.2, the ammonia concentration in the hydrogen-containing gas when the hydrogen-containing gas is generated using the natural gas containing 15% nitrogen is 2.04 ppm, and the S/C is the first By setting the value within the range equal to or less than the set value, it is possible to reduce the concentration of ammonia in the hydrogen-containing gas.

This is for the following reasons. When the S/C is set to a value within a range lower than the first set value of 3.2, which is the S/C during operation when the natural gas does not contain nitrogen, the reformer 100 to the CO remover The water vapor partial pressure in the hydrogen-containing gas supplied to 150 is lower than during normal operation, and the water vapor adsorption amount on the oxidation catalyst surface is reduced.

In addition, since water vapor and carbon monoxide are competitively adsorbed on the surface of the oxidation catalyst, the amount of carbon monoxide and hydrogen adsorbed increases as the amount of water vapor on the surface of the oxidation catalyst decreases. At this time, the nitrosyl reduction reaction shown in (Chem. 4) or (Chem. 5) proceeds on the surface of the oxidation catalyst following the formation reaction of nitrosyl shown in (Chem. 3).

(Chem. 4) and (Chem. 4) are equilibrium reactions. In (Chem. 4), the adsorption amount of water vapor, which is a product, decreases, and in (Chem. 4), the adsorption amount of carbon monoxide, which is a reactant, increases. As a result, the reactions of both (4) and (4) proceed to the right side, promoting the decomposition of nitrosyl.

By decomposing the nitrosyl adsorbed on the surface of the oxidation catalyst in this way, the ammonia decomposition activity on the oxidation catalyst is improved, and the concentration of ammonia in the hydrogen-containing gas can be reduced without providing an ammonia remover.

As described above, the hydrogen generator 350 of the present embodiment includes the reformer 100 that reforms natural gas containing hydrocarbons as a main component to generate a hydrogen-containing gas, and the hydrogen-containing gas contained in the hydrogen-containing gas. A CO remover 150 equipped with an oxidation catalyst capable of reducing the concentration of carbon monoxide by an oxidation reaction and decomposing ammonia, a raw material supplier 20 supplying natural gas to the reformer 100, and evaporating water for reforming. an evaporator 31 that supplies steam to the evaporator 100; a water supplier 30 that supplies water to the evaporator 31; an oxidizing gas supplier 40 that supplies oxidizing gas to the CO remover 150; a heater 10 that heats the mass container 100; a fuel gas supply channel 70 that supplies natural gas to the heater 10; a hydrogen-containing gas supply channel 60 that supplies hydrogen-containing gas from the CO remover 150 to the outside; Reformer temperature detector 50 for detecting the temperature of reformer 100 and information input for inputting information necessary to determine parameters relating to ammonia concentration in hydrogen-containing gas supplied to CO remover 150 and a controller 300 .

Then, the controller 300 controls the carbonization of the natural gas supplied to the reformer 100 according to the information of the natural gas supplier, which is a parameter related to the ammonia concentration in the hydrogen-containing gas supplied to the CO remover 150 . S/C, which is the ratio between the number of carbon atoms in hydrogen and the number of water molecules in water supplied to the reformer 100, is the S/C during operation when the natural gas does not contain nitrogen. The water feeder 30 and the raw material feeder 20 are controlled so as to be 2.5, which is a value within the range lower than the first set value of 3.2.

As a result, the ammonia decomposition reaction of the oxidation catalyst of the CO remover 150 can be promoted, and even when the hydrogen-containing gas is generated using the nitrogen-containing natural gas, the hydrogen-containing gas with the ammonia concentration reduced without the ammonia remover is provided. Gas can be produced and equipment costs can be reduced.

In this embodiment, the configuration and operation method of the hydrogen generator 350 described above are used, but the present invention is not limited to this, and the following configuration and operation method can be used.

In the present embodiment, the case of steam reforming the natural gas containing nitrogen as the raw material was mentioned, but the reforming reaction may be an autothermal system in which the partial oxidation reaction and the steam reforming reaction proceed simultaneously. . In this case, even if nitrogen-containing air is mixed with nitrogen-free hydrocarbons and supplied to the reformer 100 as a raw material, the same effect as in the present embodiment can be obtained.

The reforming catalyst is not limited to one supporting ruthenium, and may be one supporting nickel, for example. Moreover, the oxidation catalyst is not limited to one supporting ruthenium, and may be one supporting platinum, rhodium, or palladium, for example.

Further, in the present embodiment, the amount of air supplied from the oxidizing gas supplier 40 is set so as to supply twice as many oxygen molecules as the number of carbon monoxide molecules in the hydrogen-containing gas. However, it is not limited to this, and may be set as appropriate according to the carbon monoxide concentration in the hydrogen-containing gas discharged from the CO remover 150 .

In addition, in the present embodiment, the information of the natural gas supplier is input by the information input device 310, but the present invention is not limited to this, and the ammonia concentration in the hydrogen-containing gas supplied to the CO remover 150 is estimated. For example, it may be information on the concentration of nitrogen in natural gas, information on the type of natural gas, and location information.

Alternatively, without having the information input device 310, the ratio of the amount of natural gas supplied to the heater 10 and the calorific value of the heater 10, or the amount of natural gas supplied from the raw material supplier 20 and the reforming reaction of the reformer 100 It may be estimated by the ratio of the amount of heat absorbed at .

In the present embodiment, the hydrogen-containing gas produced by the reformer 100 is stored in the storage unit of the controller 300 with respect to the nitrogen concentration in the natural gas supplied from the supplier input to the information input device 310. Ammonia concentration inside is stored.

However, since the ammonia concentration in the hydrogen-containing gas changes depending on the amount of natural gas supplied and the change in the temperature value of the reformer 100, the ammonia concentration in the hydrogen-containing gas can be calculated using a plurality of tables or calculation formulas. can be calculated.

Further, in the present embodiment, the target value of the concentration of ammonia in the hydrogen-containing gas is set to 1 ppm, but the present invention is not limited to this. You can change it.

Also, since (Equation 1) is an experimentally obtained relational expression, it may be changed according to the ammonia resolution of the CO remover 150 .

Further, in the present embodiment, the first set value is set to 3.2 and the target value after change is set to 2.5, but it is not limited to this, and set to any effective value. I don't mind.

(Embodiment 2)
Next, Embodiment 2 of the present invention will be described.

FIG. 4 is a block diagram showing the configuration of a fuel cell system according to Embodiment 2 of the present invention. In the fuel cell system 400 of Embodiment 2 shown in FIG. 4, the same components as those of the hydrogen generator 350 of Embodiment 1 shown in FIG.

As shown in FIG. 4, the fuel cell system 400 of the present embodiment uses a natural gas containing nitrogen, which is a type of nitrogen compound, as a raw material and a fuel gas, and uses air as an oxidizing gas to produce a hydrogen-containing fuel cell system 400 . A fuel cell system 400 for generating electricity using gas, comprising: a reformer 100 for reforming natural gas to produce a hydrogen-containing gas; a reformer temperature detector 50 for detecting the temperature of the reformer 100; a raw material supplier 20 that supplies natural gas to the reformer 100; an evaporator 31 that evaporates water and supplies steam to the reformer 100; a water supplier 30 that supplies water to the evaporator 31; A CO remover 150 that reduces the concentration of carbon monoxide contained in the hydrogen-containing gas produced by the qualityr 100 by an oxidation reaction, an oxidizing gas supplier 40 that supplies air to the CO remover 150, and a CO remover 150. A hydrogen-containing gas supply channel 61 that supplies hydrogen-containing gas from the fuel cell 200 to the fuel cell 200, a fuel gas supply channel 70 that supplies natural gas to the heater 10, and a heater that heats the reformer 100. an information acquirer 311 that acquires information related to the concentration of nitrogen in the natural gas; and a controller 301 that controls the fuel cell system 400 .

The hydrogen-containing gas supply channel 61 is a channel for supplying the hydrogen-containing gas that has flowed out of the CO remover 150 to the fuel cell 200 .

The fuel cell 200 is a fuel cell 200 that generates power using the hydrogen-containing gas supplied from the hydrogen-containing gas supply channel 61, and is a PEFC using a polymer electrolyte membrane here.

The information acquirer 311 acquires information related to the nitrogen concentration in the natural gas, and here is a nitrogen concentration sensor that measures the nitrogen concentration in the natural gas.

The controller 301 controls the operation of the fuel cell system 400, and includes a signal input/output unit (not shown), an arithmetic processing unit (not shown), and a storage unit (not shown) for storing control programs. (not shown).

The operation and function of the fuel cell system 400 of the present embodiment configured as described above will be specifically described below, focusing on the differences from the first embodiment.

5 and 6 are flow charts showing the operation of the fuel cell system 400 according to the second embodiment.

As shown in FIGS. 5 and 6, the controller 301 first determines whether there is a request to start operation of the fuel cell system 400 (S21).

At this time, if there is a request to start operation of the fuel cell system 400, the controller 301 controls the heater 10 to burn the natural gas supplied to the heater 10 via the fuel gas supply path 70. An operation is performed to heat the reformer 100 (S22). Thereby, the reformer 100 is heated by the heater 10 to 660° C., which is a temperature suitable for the steam reforming reaction.

In (S21), if there is no request to start operation of the fuel cell system 400, the controller 301 continues to check whether there is a request to start operation of the fuel cell system 400 until there is a request to start operation of the fuel cell system 400. Repeat the judgment.

Next, controller 301 determines whether or not the temperature of reformer 100 detected by reformer temperature detector 50 has reached 660° C. (S23).

At this time, if the temperature of the reformer 100 detected by the reformer temperature detector 50 has reached 660° C., the raw material supplier 20, the water supplier 30, and the oxidizing gas supplier 40 are all supplied. (S24).

In (S23), if the temperature of the reformer 100 detected by the reformer temperature detector 50 has not reached 660° C., the temperature of the reformer 100 detected by the reformer temperature detector 50 is Until reaching 660°C, the controller 301 repeatedly determines whether the temperature of the reformer 100 detected by the reformer temperature detector 50 has reached 660°C.

Next, the controller 301 adjusts the raw material supplier 20, the water supplier 30, and the oxidizing gas supplier 40 to predetermined values, thereby starting hydrogen-containing gas generation (S25).

In the present embodiment, the natural gas supply rate from the raw material supplier 20 is 3.0 L/min, and the first set value, which is the S/C during operation when the natural gas does not contain nitrogen, is 3.0. The first set value of S/C of 3.0 is an appropriate value for preventing problems such as a decrease in the amount of hydrogen produced and the occurrence of carbon deposition in the reforming catalyst.

At this time, the amount of water supplied from the water supply device 30 is set at 8.43 mL/min, which is the necessary amount of water obtained from the natural gas supply amount and the S/C set value. Also, the amount of air supplied from the oxidizing gas supplier 40 is set based on the theoretical value of the carbon monoxide concentration in the hydrogen-containing gas calculated from the temperature of the reformer 100 and the S/C.

In the present embodiment, the air supply amount is set so as to supply twice as many oxygen molecules as the number of carbon monoxide molecules contained in the hydrogen-containing gas. In this embodiment, it is set to 0.81 L/min.

Next, the controller 301 adjusts the water supply device 30 and the oxidizing gas supply device 40 according to the nitrogen concentration in the natural gas detected by the information acquisition device 311 (S26), and the water supply amount is (Equation 2) , the air supply amount is changed to the value calculated by (Equation 3). Accordingly, the S/C is maintained at the first set value of 3.0 by changing the amount of water supply according to the amount of hydrocarbons in the natural gas that changes with the change in the nitrogen concentration in the natural gas. .

Here, c is the water supply rate (mL/min) from the water supplier 30, d is the nitrogen concentration (%) in the natural gas, and e is the air supply rate (L/min) from the oxidizing gas supplier 40. be.

The hydrogen-containing gas produced by the reformer 100 has carbon monoxide sufficiently reduced by the CO remover 150 and is supplied to the fuel cell 200 via the hydrogen-containing gas supply channel 61 to start power generation.

Next, the controller 301 determines whether the nitrogen concentration in the natural gas is equal to or higher than the threshold value of 2.5% (S27), and if the nitrogen concentration is equal to or higher than 2.5%, the process proceeds to (S28). If the nitrogen concentration is less than 2.5%, the process returns to (S26).

The controller 301 adjusts the raw material supplier 20, the water supplier 30, and the oxidizing gas supplier 40 to increase the natural gas supply rate and change the S/C to the second set value (S28). .

In the present embodiment, the natural gas supply rate from the raw material supplier 20 is changed to 3.2 L/min, the second set value, which is a value below the S/C of the first set value, is set to 2.5, The water supply rate from the water supply 30 is changed to 7.50 ml/min, which is the required water rate determined from the natural gas supply rate and the S/C set point.

In addition, the amount of hydrogen-containing gas supplied to the CO remover 150 increases due to the increase in the amount of natural gas supplied and the change in S/C, and the concentration of carbon monoxide in the hydrogen-containing gas increases. is changed to 1.47 L/min.

The controller 301 also adjusts the heater 10 to change the temperature of the reformer 100 to 680° C. (S29).

Next, the controller 301 adjusts the amount of water supplied from the water supplier 30 and the amount of air supplied from the oxidizing gas supplier 40 according to the nitrogen concentration in the natural gas detected by the information acquirer 311 (number 4) Change to the value calculated by (Equation 5) (S30). Accordingly, the S/C is maintained at the second set value of 2.5 by changing the amount of water supply according to the amount of hydrocarbons in the natural gas that changes due to the change in the nitrogen concentration in the natural gas. .

Next, the controller 301 determines whether the nitrogen concentration in the natural gas is less than the threshold of 2.5% (S31). At this time, if the nitrogen concentration in the natural gas is less than 2.5%, the process shifts to (S32), and if the nitrogen concentration in the natural gas is 2.5% or more, the process returns to (S30).

The controller 301 adjusts the raw material supplier 20, the water supplier 30, and the oxidizing gas supplier 40 to adjust the natural gas supply rate to 3.0 L/min, and the S/C to the first set value. is set to 3.0 (S32).

The amount of water supplied from the water supplier 30 and the amount of air supplied from the oxidizing gas supplier 40 are as follows: It is set to 8.22 mL/min, and the air supply rate from the oxidizing gas supplier 40 is also set to 0.79 L/min.

The controller 301 also adjusts the heater 10 to change the target temperature of the reformer 100 to 660° C. (S33).

Next, the controller 301 determines whether there is a request to stop the operation of the fuel cell system 400 (S34). At this time, if there is no operation stop request, the process returns to (S26) to continue operation, and if there is an operation stop request, the fuel cell system 400 stops operation.

FIG. 7 is a characteristic diagram showing the relationship between the nitrogen concentration in the natural gas, the ammonia concentration in the outlet gas of the CO remover 150, and the amount of hydrogen in the fuel cell system 400 of the second embodiment.

As shown in FIG. 7, the ammonia concentration in the hydrogen-containing gas supplied to the fuel cell 200 from the CO remover 150 via the hydrogen-containing gas supply channel 61 gradually increases as the nitrogen concentration in the natural gas increases. and reaches 0.88 ppm at a nitrogen concentration of 2.5%.

However, by changing the S/C to the second set value of 2.5 and changing the temperature of the reformer 100 from 660° C. to 680° C., the ammonia in the hydrogen-containing gas supplied to the fuel cell 200 The concentration is reduced to 0.34 ppm.

In addition, the amount of hydrogen in the hydrogen-containing gas supplied to the fuel cell 200 from the CO remover 150 via the hydrogen-containing gas supply channel 61 tends to decrease as the nitrogen concentration in the natural gas increases. , the S/C is changed to the second set value, the natural gas supply rate is increased, and the temperature of the reformer 100 is increased to 680° C., thereby increasing the S/C from 3.0 to 2.0. Even if the ratio is lowered to 5, the amount of hydrogen supplied to the fuel cell 200 can be kept substantially the same.

This makes it possible to supply the fuel cell 200 with hydrogen-containing gas in which the concentration of ammonia has been reduced to a low level while suppressing the influence on the power generation amount of the fuel cell 200 .

As described above, fuel cell system 400 of the present embodiment includes reformer 100 that reforms natural gas containing hydrocarbons and nitrogen to produce hydrogen-containing gas, and carbon monoxide contained in hydrogen-containing gas. A CO remover 150 that reduces the concentration of by oxidation reaction, a raw material supplier 20 that supplies natural gas to the reformer 100, an evaporator 31 that evaporates water and supplies steam to the reformer 100, a water supplier 30 that supplies water to the reactor 31; an oxidizing gas supplier 40 that supplies air to the CO remover 150; an information acquirer 311 that acquires information related to the concentration of nitrogen in the natural gas; A fuel cell system 400 comprising a vessel 301 and a fuel cell 200 .

Then, when the nitrogen concentration in the natural gas, which is a parameter related to the ammonia concentration in the hydrogen-containing gas supplied to the CO remover 150, reaches or exceeds a predetermined threshold value, the controller 301 controls the ratio of water to hydrocarbons. water supply 30 to change a certain S/C to a second setpoint of 2.5 below the first setpoint of 3.0 which is the operating S/C without nitrogen in the natural gas; , the raw material supplier 20 is controlled, and when changing to the second set value, the natural gas supply rate is increased and the temperature of the reformer 100 is raised.

As a result, even without an ammonia remover, the hydrogen-containing gas with sufficiently reduced ammonia concentration is supplied from the CO remover 150 to the fuel cell 200 without reducing the supply amount, resulting in a low-cost, long-life fuel cell. A system 400 can be provided.

Although the configuration and operation method of the fuel cell system 400 described above are used in the second embodiment, the present invention is not limited to this, and the following configuration and operation method can be used.

In the present embodiment, the natural gas supply rate and the water supply rate are changed at the same time, and the S/C is changed. You may

Further, in the present embodiment, the amount of air supplied from the oxidizing gas supply device 40 is set so as to supply twice as many oxygen molecules as the number of carbon monoxide molecules in the hydrogen-containing gas, which is obtained by theoretical calculation. However, it is not limited to this, and may be changed according to the carbon monoxide concentration in the hydrogen-containing gas discharged from the CO remover 150 outlet.

Further, in the present embodiment, the nitrogen concentration in the natural gas is used as the parameter related to the ammonia concentration in the hydrogen-containing gas supplied to the CO remover, but the parameter is not limited to this.

For example, the ammonia concentration in the hydrogen-containing gas discharged from the reformer 100 may be measured directly, or the nitrogen concentration in the hydrogen-containing gas discharged from the reformer 100 may be measured. Further, the estimation may be performed by acquiring information that can estimate the nitrogen concentration in the natural gas, such as information on the type of natural gas, location information, and information on the supplier of the natural gas.

Further, in the present embodiment, the threshold was set to 2.5% with respect to the nitrogen concentration in the natural gas, but it is not limited to this, and the ammonia concentration in the hydrogen-containing gas flowing out from the CO remover 150 However, it may be set within a range that can be estimated not to exceed the upper limit of the ammonia concentration required by the fuel cell 200. For example, if the upper limit of the ammonia concentration required by the fuel cell is 2 ppm, it may be set high. You can set it to a lower value to be safe.

In addition, in the present embodiment, the nitrogen concentration in the natural gas is changed to the second set value, which is the S/C of the threshold value of 2.5% or more and the first set value or less, and is less than 2.5%. Although it is changed to the first setting value, it is not limited to this, and another threshold value may be set.

Alternatively, the ammonia concentration in the reformer 100 at the nitrogen concentration in the natural gas is determined by experiment, and an appropriate S/C for the nitrogen concentration is set with reference to (Equation 1) or FIG. May be changed in response to change.

Further, in the present embodiment, the temperature of the reformer 100 is changed to 680° C. and 660° C. in (S29) and (S33) immediately after the S/C set value is changed. The temperature is not limited and may be another temperature. Also, in order to suppress the influence of the S/C change on the temperature of the reformer 100, the timing of the temperature change of the reformer 100 and the S/C change may be changed.

Further, in the present embodiment, when changing the S/C to the second set value, the natural gas supply rate is changed to 3.2 L/min, but the present invention is not limited to this, and the fuel cell 200 is required. The natural gas supply rate may be varied to produce a hydrogen-containing gas amount of .

Further, in the present embodiment, in (S25), (S28), and (S32), the natural gas supply rates are set to 3.0 L/min, 3.2 L/min, and 3.0 L/min, respectively, Although the set value is changed only when the threshold is crossed, it is not limited to this, and may be changed according to the nitrogen concentration in the natural gas.

As described above, the hydrogen generator of the present invention can supply a hydrogen-containing gas with a sufficiently reduced ammonia concentration without an ammonia remover. It is most suitable for a hydrogen generator that generates a hydrogen-containing gas with a low carbon concentration and a fuel cell system using the same.

20 raw material supplier 30 water supplier 40 oxidizing gas supplier 100 reformer 150 CO remover 200 fuel cell 300 controller 301 controller 310 information input device 311 information acquisition device 350 hydrogen generator 400 fuel cell system

Claims (9)

A reformer that reforms a raw material containing hydrocarbon as a main component to generate a hydrogen-containing gas, and an oxidation that reduces the concentration of carbon monoxide contained in the hydrogen-containing gas by an oxidation reaction and decomposes ammonia. A CO remover equipped with a catalyst, a raw material supplier for supplying the raw material to the reformer, a water supplier for supplying water to the reformer, and an oxidizing gas supplier for supplying the oxidizing gas to the CO remover. and a controller, wherein the feedstock includes a nitrogen compound, and the controller controls carbonization in the feedstock according to a parameter relating to ammonia concentration in the hydrogen-containing gas supplied to the CO remover. S/C, which is the ratio of the number of carbon atoms of hydrogen and the number of water molecules of the water supplied to the reformer, is the S/C during operation when the raw material does not contain nitrogen compounds. The water feeder and the water feeder so as to change the water vapor partial pressure in the hydrogen-containing gas supplied from the reformer to the CO remover to a value within the range of C or less than the first set value so as to decrease. , and the raw material supplier. The controller sets the S/C to the first set value when the parameter is less than the predetermined threshold, and sets the S/C to the first set value when the parameter is greater than or equal to the predetermined threshold. 2. The hydrogen generator according to claim 1, wherein said water supplier and said raw material supplier are controlled to set a second set value less than a first set value. 3. The hydrogen generator according to claim 1, wherein said parameter is determined based on information relating to the concentration of nitrogen compounds in said raw material. 4. The hydrogen generator according to claim 3, further comprising an information acquirer for acquiring said information. The information is any one of information on the concentration of the nitrogen compound, information on the type of the raw material, information on the location of the hydrogen generator , and information on the supplier of the raw material. 5. The hydrogen generator according to 3 or 4. 6. The hydrogen generator according to any one of claims 1 to 5, wherein the controller controls the raw material supplier so as to change the raw material supply amount when changing the S/C. . A heater for heating the reformer is further provided, and the controller adjusts the temperature of the reformer to a value equal to or lower than the first set value when changing the S/C to a value equal to or lower than the first set value. 7. The method according to any one of claims 1 to 6, characterized in that the heater is controlled to raise the temperature above a first setpoint, which is the temperature of the reformer when no compound is contained. hydrogen generator. A fuel cell system comprising: the hydrogen generator according to any one of claims 1 to 7; and a fuel cell that generates power using the hydrogen-containing gas supplied from the hydrogen generator. A reformer that reforms a raw material containing hydrocarbon as a main component to generate a hydrogen-containing gas, and an oxidation that reduces the concentration of carbon monoxide contained in the hydrogen-containing gas by an oxidation reaction and decomposes ammonia. A CO remover equipped with a catalyst, a raw material supplier for supplying the raw material to the reformer, a water supplier for supplying water to the reformer, and an oxidizing gas supplier for supplying the oxidizing gas to the CO remover. wherein the feedstock contains nitrogen compounds, and carbonization in the feedstock is controlled according to a parameter relating to ammonia concentration in the hydrogen-containing gas supplied to the CO remover. S/C, which is the ratio of the number of carbon atoms of hydrogen to the number of water molecules of water supplied to the reformer, is equal to or less than the S/C during operation when the raw material does not contain nitrogen compounds. A method of operating a hydrogen generator, characterized in that the water vapor partial pressure in the hydrogen-containing gas supplied from the reformer to the CO remover is changed to a value within the range of .

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