JP6846714B2 - Catalyst composition, hydrogen production equipment, and hydrogen production method - Google Patents

Description

The present invention relates to a catalyst composition that promotes a hydrocarbon decomposition reaction, a hydrogen production apparatus, and a hydrogen production method.

Conventionally, a technique for producing hydrogen by steam reforming a hydrocarbon such as methane has been put into practical use (for example, Patent Document 1).

However, when hydrocarbons are reformed by steam, there is a problem that not only hydrogen but also carbon dioxide is generated. Since carbon dioxide is a factor of global warming, it is required to reduce its emission to the atmosphere.

Therefore, a technique for producing hydrogen by reducing carbon dioxide emissions by thermally decomposing hydrocarbons in the presence of a catalyst has been developed.

Japanese Unexamined Patent Publication No. 2014-136655

There is a need for the development of a catalyst composition that more efficiently promotes the decomposition reaction of the above hydrocarbons.

In view of such problems, the present invention provides a catalyst composition capable of more efficiently promoting the decomposition reaction of hydrocarbons, a hydrogen production apparatus using the catalyst composition, and a hydrogen production method. I am aiming.

In order to solve the above problems, the catalyst composition according to the present invention is supported on a proton-conducting solid oxide that functions as a carrier and a solid oxide, and directly decomposes hydrocarbons into solid carbon and hydrogen. comprising a catalyst to accelerate the decomposition reaction, a pellet shape or a particle diameter of Ru 300μm following powder der least 150 [mu] m.

Further, the proton-conducting solid _{oxide, Ba (Zr 1-y Ce} y) 1-x (A 1-z B z) x O 3-δ ( However, x = 0.05 to 0.5, y = 0 or more and 1 or less, z = 0 or more and 1 or less, A = Y, Yb, Sc, Gd, or In, or B = Y, Yb, Sc, Gd, or In) , LaYbO _3-δ , and LaScO _3-δ may be any one or more.

In order to solve the above problems, the hydrogen production apparatus according to the present invention is supported on a proton-conducting solid oxide that functions as a carrier and a solid oxide, and directly decomposes hydrocarbons into solid carbon and hydrogen. The catalyst composition comprises a reaction unit containing a catalyst composition having a catalyst for promoting the decomposition reaction, and a raw material gas supply unit for supplying a raw material gas containing a hydrocarbon to the reaction unit, and the catalyst composition has a pellet shape or a pellet shape. , a particle size of Ru 300μm or less of the powder der more than 150μm.

Further, a regenerated gas supply unit that supplies a regenerated gas containing any one or more of water vapor, oxygen, and carbon dioxide to the reaction unit may be provided.

In order to solve the above problems, the hydrogen production method according to the present invention directly decomposes hydrocarbons into solid carbon and hydrogen, which are supported on a proton-conducting solid oxide and a solid oxide that function as a carrier. the reaction section in which the catalyst composition is housed with a catalyst which promotes the decomposition reaction of, look including the step of supplying a raw material gas containing hydrocarbon, the catalyst composition, a pellet shape 300μm or a particle size of 150μm or more, The following powders .

Further, after performing the step of supplying the raw material gas, a step of supplying the regenerated gas containing any one or more of steam, oxygen, and carbon dioxide to the reaction unit may be included.

According to the present invention, it is possible to more efficiently promote the decomposition reaction of hydrocarbons.

It is a figure explaining the hydrogen production apparatus. It is a flowchart explaining the process flow of a hydrogen production method. It is a figure explaining the change of the weight of a catalyst composition. It is a figure explaining the temperature dependence of an Example. It is a figure explaining the repetition characteristic of an Example.

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in such an embodiment are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are designated by the same reference numerals to omit duplicate description, and elements not directly related to the present invention are not shown. To do.

(Hydrogen production device 100)
FIG. 1 is a diagram illustrating a hydrogen production apparatus 100. In FIG. 1, the gas flow is indicated by a solid arrow. As shown in FIG. 1, the hydrogen production apparatus 100 includes a reaction unit 110, a raw material gas supply unit 120, and a regenerated gas supply unit 130. In this embodiment, CH ₄ (methane) will be described as an example of hydrocarbon.

The catalyst composition is contained in the reaction unit 110. The catalyst composition is a solid oxide in which a catalyst is supported. The catalyst promotes a hydrocarbon decomposition reaction (for example, a methane decomposition reaction represented by the following reaction formula (1)), and for example, Fe (iron), Ni (nickel), Co (cobalt), Cu ( (Copper), Mn (manganese), Mo (molybdenum), or any one or more.
CH ₄ → C + 2H ₂ … Reaction equation (1)

The solid oxide is a proton- ^{conducting solid oxide having a proton (H +} ) as a conducting ion. Proton conductive solid oxide, for _{example, Ba (Zr 1-y Ce} y) 1-x (A 1-z B z) x O 3-δ ( However, x = 0.05 to 0.5, y = 0 or more and 1 or less, z = 0 or more and 1 or less, A = Y, Yb, Sc, Gd, or In, or B = Y, Yb, Sc, Gd, or In) , LaYbO _3-δ , and LaScO _3-δ , preferably one or more, preferably BrZrYO _3-δ , and more preferably BrZr _0.9 Y _0.1 O _3-δ .

The reaction unit 110 maintains the storage space of the catalyst composition at a predetermined temperature of, for example, 500 ° C. or higher, preferably 600 ° C. or higher.

The raw material gas supply unit 120 is composed of, for example, a pump. The raw material gas supply unit 120 is connected to the methane supply source 102 on the suction side and to the reaction unit 110 on the discharge side. When methane is supplied to the reaction unit 110 by the raw material gas supply unit 120, the decomposition reaction (pyrolysis reaction) represented by the above reaction formula (1) proceeds on the catalyst composition. As a result, H ₂ (hydrogen) is produced from methane.

As described above, the catalyst composition contains a proton-conducting solid oxide as a carrier of the catalyst. As a result, in the catalyst composition, protons can be transferred from the hydrocarbon (extracting the proton from the hydrocarbon) via the solid oxide. Therefore, it is possible to further promote the decomposition reaction of hydrocarbons as compared with the conventional catalyst composition containing no proton conduction type solid oxide.

The regenerated gas supply unit 130 is composed of, for example, a pump. In the regenerated gas supply unit 130, the suction side is connected to the regenerated gas supply source 104, and the discharge side is connected to the reaction unit 110. The regenerated gas supply unit 130 is driven exclusively with the raw material gas supply unit 120. The regenerated gas is a gas that gasifies solid carbon, and is, for example, one or more of water vapor, oxygen, and carbon dioxide.

When the reaction represented by the reaction formula (1) is carried out, solid carbon is precipitated on the catalyst composition (catalyst), and the function (activity) of the catalyst is lowered. Therefore, the solid carbon precipitated on the catalyst composition can be gasified and removed by the configuration including the regenerated gas supply unit 130. This makes it possible to regenerate the function of the catalyst.

When the regenerated gas supply unit 130 supplies a gas containing water vapor as a regenerated gas to the reaction unit 110, the reaction represented by the following reaction formula (2) proceeds, and a useful synthetic gas (carbon monoxide and hydrogen) is converted from solid carbon. Mixed gas) can be produced.
C + H ₂ O → CO + H ₂ … Reaction equation (2)

(Hydrogen production method)
Subsequently, a hydrogen production method using the hydrogen production apparatus 100 will be described. FIG. 2 is a flowchart illustrating a processing flow of the hydrogen production method.

(Hydrogen production process S110)
The hydrogen production step S110 is a step of driving the raw material gas supply unit 120 to supply the raw material gas to the reaction unit 110. By carrying out the hydrogen production step S110, for example, the reaction represented by the above reaction formula (1) proceeds, and hydrogen can be produced in the reaction unit 110.

(First determination step S120)
The first determination step S120 is a step of determining whether or not the catalyst composition (catalyst) contained in the reaction unit 110 has deteriorated. The first determination step S120 is executed until it is determined that the catalyst composition has deteriorated (NO in S120), and when it is determined that the catalyst composition has deteriorated (YES in S120), the raw material gas supply unit 120 is stopped. Then, the process is transferred to the regeneration step S130.

In the first determination step S120, it is sufficient that it can be determined whether or not the catalyst composition has deteriorated, and the specific processing of the determination is not limited. For example, it may be determined that the catalyst composition has deteriorated when a predetermined time has elapsed from the start of the hydrogen production step S110. Further, when the weight of the catalyst composition exceeds a predetermined value, that is, when the solid carbon precipitated in the catalyst composition exceeds a predetermined value, it may be determined that the catalyst composition has deteriorated. Further, when the content (concentration) of hydrogen in the produced gas sent from the reaction unit 110 is less than a predetermined value, it may be determined that the catalyst composition has deteriorated.

(Regeneration step S130)
The regeneration step S130 is a step of driving the regeneration gas supply unit 130 to supply the regeneration gas to the reaction unit 110. By carrying out the regeneration step S130, for example, the reaction represented by the above reaction formula (2) proceeds, and the solid carbon precipitated on the catalyst composition can be gasified and removed from the catalyst composition.

(Second determination step S140)
The second determination step S140 determines whether the function of the catalyst composition (catalyst) has improved, that is, whether the activity of the catalyst has improved as compared with the state determined to have deteriorated in the first determination step S120. It is a process. The second determination step S140 is performed until it is determined that the function of the catalyst composition is improved (NO in S140), and when the function of the catalyst composition is improved (YES in S140), the regenerated gas supply unit 130 is operated. The process is stopped and the process from the hydrogen production step S110 is repeated.

In the second determination step S140, it is sufficient that it can be determined whether or not the function of the catalyst composition is improved, and the specific processing of the determination is not limited. For example, it may be determined that the function of the catalyst composition has improved when a predetermined time has elapsed from the start of the regeneration step S130.

As described above, the hydrogen production apparatus 100 of the present embodiment and the hydrogen production method using the hydrogen production apparatus 100 include a catalyst that promotes a hydrocarbon decomposition reaction and a proton-conducting solid oxide. Since the hydrocarbon is decomposed using the above, the decomposition reaction of the hydrocarbon can be further promoted as compared with the conventional catalyst composition containing no proton conduction type solid oxide.

(Example)
A catalyst composition in which Fe was supported on BaZr _0.9 Y _0.1 O _{3-δ was produced by the solid phase method.} Specifically, _{61.8 wt% (weight%) of BaCO 3} (barium carbonate), 3.5 wt% of Y ₂ O ₃ (yttrium oxide), and 34.7 wt% of ZrO ₂ (zirconia) are mixed and powdered. Made into a body (crushed). Then, the mixture was calcined at 1400 ° C. for 5 hours in an air atmosphere to produce BaZr _0.9 Y _0.1 O _3-δ (proton conduction type solid oxide). Subsequently, 0.135 g of graphite (to form multiple pores), BaZr _0.9 Y _0.1 O _3-δ 2.1 g, Fe ₂ O ₃ (iron (III) oxide) 0.9 g, ethyl cellulose 0.03 g (binder) was mixed in ethanol for 20 hours to prepare a powder. Then, ethanol was evaporated and removed from the mixture, and then compression-molded into pellets at 32 MPa. Subsequently, the pellets were calcined at 1000 ° C. for 5 hours in an air atmosphere. Then, the calcined pellets were crushed and sieved to obtain a catalyst composition (Example) having a particle size of 150 μm or more and 300 μm or less and _{carrying 30 wt% of Fe 2} O _3.

(Methane decomposition characteristics)
10 mg of the catalyst composition was contained in the reaction unit 110, the raw material gas was supplied to the reaction unit 110, and the change in weight (wt%) of the catalyst composition was measured. The temperature of the reaction unit 110 was set to 800 ° C. The raw material gas was a mixed gas of 5% methane and 95% argon (Ar). Further, the raw material gas supply unit 120 supplied the raw material gas to the reaction unit 110 at 200 ml / min. Moreover, the weight change of the catalyst composition was measured for each of the cases where Example, Comparative Example A, Comparative Example B, and Comparative Example C were contained as the catalyst composition. An example is _{BaZr 0.9} Y _0.1 O _3-δ in which _{the above Fe 2} O ₃ is supported by 30 wt%. Comparative Example A is yttria-stabilized zirconia (YSZ, an oxide ion-conducting solid oxide) in which 30 wt% of _{Fe 2} O _{3 is supported.} Comparative Example B is a BaZrO _{3 to Fe} 2 _{O 3} is carried 30 wt%. Comparative Example C is BaZr _0.8 Fe _0.2 O _3-δ .

FIG. 3 is a diagram illustrating a change in the weight of the catalyst composition. In FIG. 3, the vertical axis represents the weight change (wt%), and the horizontal axis represents the time (seconds). Further, in FIG. 3, Examples are shown by a solid line, Comparative Example A is shown by a broken line, Comparative Example B is shown by a alternate long and short dash line, and Comparative Example C is indicated by a two-dot chain line.

As shown in FIG. 3, in Examples, Comparative Example A, and Comparative Example B containing the catalyst (Fe), it was found that the weight of the catalyst composition increased with the passage of time. That is, in Examples, Comparative Example A, and Comparative Example B, the amount of solid carbon precipitated increases with the passage of time. Therefore, in Examples, Comparative Example A, and Comparative Example B, it was confirmed that the methane decomposition reaction proceeded. On the other hand, in Comparative Example C containing no catalyst, the weight hardly changes over time.

Further, it was found that in the examples, the amount of increase in the weight of the catalyst composition was larger than that in the comparative examples A and B. From this, it was confirmed that the examples can decompose methane more efficiently than the comparative examples A and B. That is, a catalyst composition using a proton-conducting solid oxide as a carrier efficiently decomposes hydrocarbons as compared with a catalyst composition using another solid oxide such as an oxide ion-conducting type as a carrier. It turns out that it can be promoted.

(Temperature dependence)
10 mg of the catalyst composition of the example was contained in the reaction unit 110, the raw material gas was supplied to the reaction unit 110, and the amount of solid carbon produced was measured. The temperature of the reaction unit 110 was 700 ° C, 800 ° C, and 900 ° C. The raw material gas was a mixed gas of 5% methane and 95% argon. Further, the raw material gas supply unit 120 supplied the raw material gas to the reaction unit 110 at 200 ml / min.

FIG. 4 is a diagram illustrating the temperature dependence of the embodiment. In FIG. 4, the vertical axis indicates the production ratio of solid carbon normalized by the final amount of solid carbon produced (the amount of solid carbon produced when the reaction is carried out for infinite time), and the horizontal axis represents the production ratio of solid carbon. Indicates time (seconds). Further, in FIG. 4, the case where the reaction unit 110 is set to 900 ° C. is shown by a solid line. The case of 800 ° C. is indicated by a broken line, and the case of 700 ° C. is indicated by a dashed line.

As shown in FIG. 4, it was confirmed that when the reaction unit 110 was at 900 ° C., it reached a steady state in about 180 seconds. It was also found that when the reaction unit 110 was at 800 ° C., it reached a steady state in about 250 seconds. Furthermore, it was confirmed that methane can be efficiently decomposed even when the reaction unit 110 is at 700 ° C.

(Repeat characteristics)
10 mg of the catalyst composition of the example was housed in the reaction unit 110, and the hydrogen production step S110 and the regeneration step S130 were repeated 12 times.

In the hydrogen production step S110, the temperature of the reaction unit 110 was set to 800 ° C. The raw material gas was a mixed gas of 5% methane and 95% argon. Further, the raw material gas supply unit 120 supplied the raw material gas to the reaction unit 110 at 200 ml / min.

In the regeneration step S130, the temperature of the reaction unit 110 was set to 800 ° C. The regenerated gas was hydrogen. Further, the regenerated gas supply unit 130 supplied the regenerated gas to the reaction unit 110 at 200 ml / min.

FIG. 5 is a diagram illustrating the repeating characteristics of the embodiment. In FIG. 5, the left vertical axis shows the amount of solid carbon precipitated (wt%), the right vertical axis shows the Fe reduction time (1 / sec) in the examples, and the horizontal axis shows the hydrogen production process. The number of times S110 and the regeneration step S130 are performed is shown. Further, in FIG. 5, the amount of solid carbon precipitated (wt%) is indicated by a black circle, and the reduction time of Fe is indicated by a white square.

As shown in FIG. 5, the amount of solid carbon precipitated by carrying out the hydrogen production step S110 is the largest at the first time and decreases as the number of times increases from the second time to the third time. However, after the third time, it was confirmed that the amount of solid carbon precipitated did not decrease even if the number of times increased.

Further, the reduction time of Fe by carrying out the regeneration step S130 is the shortest in the first time, and increases as the number of times increases in the second and third times. However, it was confirmed that the reduction time of Fe did not increase even if the number of times increased after the third time. As a result, it can be inferred that the fine structure of the catalyst composition is stable even if the hydrogen production step S110 and the regeneration step S130 are repeated.

From the above results, it was confirmed that the catalyst composition using the proton conduction type solid oxide as a carrier does not deteriorate the function of the catalyst even if the hydrogen production step S110 and the regeneration step S130 are repeatedly carried out.

The conventional catalyst composition that does not contain a proton-conducting solid oxide has a problem that the catalyst composition cannot be repeatedly used because the function of the catalyst is deteriorated when the treatment for removing the solid carbon is performed. On the other hand, in the catalyst composition of the present embodiment, even if the hydrogen production step S110 and the regeneration step S130 are repeated a plurality of times, deterioration of the catalyst function can be prevented. Therefore, the catalyst composition can be used repeatedly, and the cost required for the catalyst composition can be reduced. As a result, hydrogen can be produced at low cost.

Although the preferred embodiment of the present invention has been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such an embodiment. It is clear that a person skilled in the art can come up with various modifications or modifications within the scope of the claims, which naturally belong to the technical scope of the present invention. Understood.

For example, in the above embodiment, methane has been described as an example of the hydrocarbon that the catalyst composition decomposes. Hydrocarbons are not limited to methane. For example, it may be ethane, propane, butane, ethylene, propylene, butylene, etc., or a mixed gas of two or more of methane, ethane, propane, butane, ethylene, propylene, and butylene (for example, city gas, Natural gas, oil gas) may be used.

Further, in the above embodiment, a catalyst composition in which a catalyst is supported on a proton-conducting solid oxide has been described as an example. However, the catalyst composition may contain a catalyst that promotes the decomposition reaction of hydrocarbons and a proton-conducting solid oxide.

Further, in the above embodiment, the configuration in which the hydrogen production apparatus 100 includes the regenerated gas supply unit 130 has been described as an example. However, the regenerated gas supply unit 130 is not an indispensable configuration. Similarly, in the hydrogen production method, the case where the regeneration step S130 is carried out has been described as an example. However, the regeneration step S130 is not an essential process.

The present invention can be used in a catalyst composition that promotes a hydrocarbon decomposition reaction, a hydrogen production apparatus, and a hydrogen production method.

100 Hydrogen production equipment 120 Raw material gas supply unit 130 Recycled gas supply unit S110 Hydrogen production process S130 Regeneration process

Claims (6)

A proton-conducting solid oxide that functions as a carrier,
A catalyst supported on the solid oxide that promotes a decomposition reaction that directly decomposes hydrocarbons into solid carbon and hydrogen.
With
Pellet form, or a particle diameter of Ru 300μm following powder der than 150μm catalyst composition. The proton conductive solid _{oxide, Ba (Zr 1-y Ce} y) 1-x (A 1-z B z) x O 3-δ ( However, x = 0.05 to 0.5, y = 0 or more and 1 or less, z = 0 or more and 1 or less, A = Y, Yb, Sc, Gd, or In, B = Y, Yb, Sc, Gd, or In), The catalyst composition according to claim 1, which is any one or more of LaYbO _3-δ and LaScO _3-δ. It contained a proton-conducting solid oxide that functions as a carrier , and a catalyst composition that is supported on the solid oxide and has a catalyst that promotes a decomposition reaction that directly decomposes hydrocarbons into solid carbon and hydrogen. Reaction part and
A raw material gas supply unit that supplies a raw material gas containing a hydrocarbon to the reaction unit, and a raw material gas supply unit.
Equipped with a,
The catalyst composition, pellet form, or a particle diameter of 150μm or more 300μm following powder Der Ru hydrogen production apparatus. The hydrogen production apparatus according to claim 3, further comprising a regenerated gas supply unit that supplies a regenerated gas containing any one or more of steam, oxygen, and carbon dioxide to the reaction unit. It contained a proton-conducting solid oxide that functions as a carrier and a catalyst composition that is supported on the solid oxide and has a catalyst that promotes a decomposition reaction that directly decomposes hydrocarbons into solid carbon and hydrogen. the reaction section, viewed including the step of supplying a raw material gas containing hydrocarbon,
The method for producing hydrogen , wherein the catalyst composition is a powder having a pellet shape or a particle size of 150 μm or more and 300 μm or less. After performing the step of supplying the raw material gas,
The hydrogen production method according to claim 5, further comprising a step of supplying a regenerated gas containing any one or more of steam, oxygen, and carbon dioxide to the reaction unit.

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