Ammonia dehydrogenation catalyst and method for producing hydrogen

Abstract

Disclosed are an ammonia dehydrogenation catalyst with which hydrogen can be produced from ammonia in a high yield, and a method for producing hydrogen. The disclosed ammonia dehydrogenation catalyst includes nickel (Ni), lanthanide elements (M), and aluminum (Al).

Description

Catalyst for ammonia dehydrogenation and method for producing hydrogen

[0001] A catalyst for ammonia dehydrogenation and a method for producing hydrogen are disclosed. More specifically, a catalyst for ammonia dehydrogenation and a method for producing hydrogen are disclosed, which can produce hydrogen from ammonia at a high yield.

[0002] Recently, global interest in the production and utilization of hydrogen energy (blue and green hydrogen) as a sustainable and environmentally friendly alternative energy source that does not emit carbon dioxide has been increasing.

[0003] Hydrogen energy production methods include green hydrogen production through water electrolysis using electricity generated from eco-friendly energy sources such as solar and wind power, and pink hydrogen production based on nuclear power. However, in countries lacking eco-friendly energy sources, the high cost of producing hydrogen using these methods makes it commercially unviable, leading to dependence on imports. Liquefied hydrogen, ammonia, and liquid organic hydrogen carriers (LOHCs) are being discussed as hydrogen carriers. Among these, ammonia is expected to have the highest potential for commercialization in the near future due to its ease of storage and transportation compared to liquefied hydrogen and the ability to utilize existing infrastructure. Notably, ammonia is not only a hydrogen carrier but can also be utilized as an energy source itself, and with the right catalyst, hydrogen can be produced through dehydrogenation.

[0004] The potential applications of producing hydrogen from ammonia using the above method are as follows. First, refineries such as Hyundai Oilbank are planning to modify and supplement existing gas stations that already provide gasoline, diesel, and LPG to create future gas stations (combined energy stations) that will provide a full range of transportation fuels and energy, including gasoline, diesel, and LPG, along with hydrogen and electric charging, all in one place. In particular, if "hydrogen-based vehicles utilizing fuel cells" currently under development by Hyundai Motor Company and others are commercialized, refineries are expected to supply hydrogen to these future gas stations. Therefore, hydrogen produced from ammonia is expected to be supplied to gas stations and utilized as a raw material for fuel cells. In addition, the oil refining and petrochemical industries require large amounts of hydrogen to produce various products. If this hydrogen is produced through an environmentally friendly ammonia dehydrogenation process that does not emit carbon dioxide, rather than through processes that emit significant amounts of carbon dioxide, such as the existing steam methane reforming or natural gas reforming, it is expected that carbon dioxide emissions can be reduced. Furthermore, the use of hydrogen produced through ammonia dehydrogenation for power generation can be considered. Ammonia itself can be used as a power generation feedstock to produce energy through combustion without emitting carbon dioxide. However, ammonia has inherent characteristics that cause chronic problems such as low calorific value and difficulty in ignition. To solve these problems, methods have been proposed that convert only a portion of ammonia to hydrogen and then produce energy through ammonia-hydrogen co-firing, or convert all ammonia to hydrogen and then produce energy through hydrogen combustion. In this case, it is thought that it will be possible to produce energy in an environmentally friendly manner by utilizing the advantages of hydrogen, such as its high calorific value and ease of ignition.Moreover, ammonia can not only produce energy through co-firing or combustion with hydrogen, but also can be converted to hydrogen and used in fuel cells, resulting in environmentally friendly energy production. More specifically, depending on the target power generation capacity, it is thought that it is possible to convert only some or all of the ammonia into hydrogen and then use the hydrogen produced in this way as a raw material for fuel cells to produce energy corresponding to the required power generation capacity. Another possible use of ammonia is as a fuel for ships. Similar to the previous power generation example, ammonia can be used as fuel to produce energy for ship propulsion. Therefore, if ammonia is converted only some or all of the way to hydrogen, it is thought that it is possible to propel ships by co-firing ammonia and hydrogen, combustion of hydrogen, or through linkage with additional fuel cells.

[0005] Accordingly, interest in the technology for producing hydrogen by dehydrogenating ammonia is increasing worldwide, and it is expected that if a high-performance ammonia dehydrogenation catalyst is developed, hydrogen production through such a catalyst and the application of the hydrogen produced in this way to various purposes will be possible.

[0006] Ruthenium (Ru)-based catalysts, typically used to manufacture highly active ammonia dehydrogenation catalysts, are expensive. When converting existing onshore natural gas reforming hydrogen production plants to ammonia dehydrogenation, the process can vary depending on the purity of the hydrogen to be produced. However, pressure swing adsorption (PSA) is typically used to increase the purity of the produced hydrogen. To improve the economic efficiency and energy efficiency of the overall process, liquid ammonia is vaporized and injected into the reaction chamber at pressures exceeding 10 atm before ammonia dehydrogenation is performed. In this case, ammonia dehydrogenation is a volume-intensive reaction, which results in lower ammonia conversion compared to atmospheric pressure. To compensate for this, an increased catalyst loading or a higher reaction temperature is likely required. High ammonia dehydrogenation reaction temperatures can accelerate catalyst deactivation due to factors such as metal agglomeration. Therefore, it is essential to develop a catalyst that has high activity even at low temperatures while minimizing the Ru content or replacing it with a non-precious metal, and the development of such a catalyst is currently in demand worldwide.

[0007] One embodiment of the present invention provides a catalyst for ammonia dehydrogenation capable of producing hydrogen from ammonia at a high yield.

[0008] Another embodiment of the present invention provides a method for producing hydrogen from ammonia using the ammonia dehydrogenation catalyst.

[0009] One aspect of the present invention is:

[0010] A catalyst for ammonia dehydrogenation comprising nickel (Ni), a lanthanide element (M), and aluminum (Al) is provided.

[0011] The above lanthanide element (M) may include La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu or a combination thereof.

[0012] The content of the above aluminum (Al) may be 1 to 8 parts by weight based on 100 parts by weight of the ammonia dehydrogenation catalyst.

[0013] The molar ratio (Ni / M) of the nickel (Ni) to the lanthanide element (M) may be 1 to 6.

[0014] In the above ammonia dehydrogenation catalyst, the nickel (Ni), the lanthanide element (M), and the aluminum (Al) may exist in the form of a mixed metal oxide.

[0015] The above ammonia dehydrogenation catalyst is 50 to 300 m 2 / g can have a BET surface area.

[0016] Another aspect of the present invention is:

[0017] A method for producing hydrogen is provided, including a step (S100) of contacting ammonia with a catalyst for ammonia dehydrogenation to produce hydrogen.

[0018] The above step (S100) can be performed at a temperature of 300°C to 700°C.

[0019] The above step (S100) is 500hr -1 25,000hr -1 can be performed at the spatial velocity of .

[0020] A catalyst for ammonia dehydrogenation according to one embodiment of the present invention can produce hydrogen from ammonia at a high yield.

[0021] Hereinafter, a catalyst for ammonia dehydrogenation according to one embodiment of the present invention will be described in detail.

[0022] In this specification, “mixed metal oxide” means a metal oxide containing three or more metals, manufactured by a method other than the impregnation method.

[0023] Also, in this specification, the term "impregnation method" generally refers to a method used when supporting an active metal and / or a co-catalyst on a support (or carrier), which means a method of adding a solution in an amount corresponding to the pore volume of the support to the support to support the active metal or co-catalyst on the surface of the support.

[0024] Also, in this specification, the term "precipitation method" means a method of forming a solid particle with low solubility by reacting a metal precursor solution and a precipitant solution with each other, and then precipitating the solid particle to obtain a metal oxide catalyst, and then filtering the precipitated solid particle from the solution, washing it, and, if necessary, heat treating it.

[0025] Also, in this specification, “conversion of ammonia” means a value calculated according to the following mathematical formula 1:

[0026] [Mathematical Formula 1]

[0027] Ammonia conversion rate (%) = moles of ammonia reacted / moles of ammonia initially supplied × 100.

[0028] A catalyst for ammonia dehydrogenation according to one embodiment of the present invention comprises nickel (Ni), a lanthanide element (M), and aluminum (Al).

[0029] The above lanthanide element (M) may include La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu or a combination thereof.

[0030] The content of the above aluminum (Al) (based on the metal, not the metal oxide) may be 1 to 8 parts by weight per 100 parts by weight of the ammonia dehydrogenation catalyst. When the content of the above aluminum is within the above range, an ammonia dehydrogenation catalyst capable of improving the ammonia conversion rate can be obtained.

[0031] The molar ratio (Ni / M) of the nickel (Ni) to the lanthanide element (M) (based on the metal, not the metal oxide) may be 1 to 6. When the molar ratio (Ni / M) of the nickel (Ni) to the lanthanide element (M) is within the above range, an ammonia dehydrogenation catalyst capable of improving the ammonia conversion rate can be obtained.

[0032] In the above ammonia dehydrogenation catalyst, the nickel (Ni), the lanthanide element (M), and the aluminum (Al) may exist in the form of a mixed metal oxide.

[0033] 50-300m of the above ammonia dehydrogenation catalyst 2 / g can have a BET surface area.

[0034] Hereinafter, a hydrogen production method according to one embodiment of the present invention using the ammonia dehydrogenation catalyst will be described in detail.

[0035] A method for producing hydrogen according to one embodiment of the present invention may include a step (S100) of producing hydrogen by contacting ammonia with the ammonia dehydrogenation catalyst described above.

[0036] The above step (S100) can be performed at a temperature of 300°C to 700°C.

[0037] In addition, the above step (S100) is 500hr -1 25,000hr -1 It can be performed at gas hourly space velocity (GHSV).

[0038] Hereinafter, the present invention will be described with reference to the following examples, but the present invention is not limited to the following examples.

[0039] Example 1: Preparation of a catalyst for ammonia dehydrogenation

[0040] A catalyst for ammonia dehydrogenation was prepared using a precipitation method. Specifically, a basic precipitant was used to prepare a carbonate anion (CO3) in an aqueous solution. 2- ) is used to generate carbonate, and nickel cations (Ni) in aqueous solution are used as a nickel (Ni) source. 2+ ) is used to generate nickel compounds, and cerium (Ce) cations (Ce) in aqueous solution are used as a cerium (Ce) source. 3+ , Ce 4+ ) is used to generate cerium compounds, and aluminum cations (Al) in aqueous solution are used as aluminum (Al) sources. 3+ ) was used to produce an aluminum compound.

[0041] Then, after the completion of the precipitation process, the precipitated solid was dried at 80°C for 12 hours and then calcined at 500°C for 4 hours to obtain an ammonia dehydrogenation catalyst. At this time, the content of aluminum (Al) in the prepared ammonia dehydrogenation catalyst (based on the metal, not the metal oxide) was adjusted to 2 parts by weight (i.e., based on 100 parts by weight of the prepared ammonia dehydrogenation catalyst), and the molar ratio of nickel (Ni) to cerium (Ce) (Ni / Ce) (based on the metal, not the metal oxide) was adjusted to 2.

[0042] Example 2: Preparation of a catalyst for ammonia dehydrogenation

[0043] An ammonia dehydrogenation catalyst was manufactured in the same manner as in Example 1, except that the content of aluminum (Al) (based on metal, not metal oxide) in the manufactured ammonia dehydrogenation catalyst was adjusted to 1 part by weight (i.e., based on 100 parts by weight of the manufactured ammonia dehydrogenation catalyst).

[0044] Example 3: Preparation of a catalyst for ammonia dehydrogenation

[0045] An ammonia dehydrogenation catalyst was manufactured in the same manner as in Example 1, except that the content of aluminum (Al) (based on metal, not metal oxide) in the manufactured ammonia dehydrogenation catalyst was adjusted to 6 parts by weight (i.e., based on 100 parts by weight of the manufactured ammonia dehydrogenation catalyst).

[0046] Example 4: Preparation of a catalyst for ammonia dehydrogenation

[0047] An ammonia dehydrogenation catalyst was manufactured in the same manner as in Example 1, except that the content of aluminum (Al) (based on metal, not metal oxide) in the manufactured ammonia dehydrogenation catalyst was adjusted to 8 parts by weight (i.e., based on 100 parts by weight of the manufactured ammonia dehydrogenation catalyst).

[0048] Example 5: Preparation of a catalyst for ammonia dehydrogenation

[0049] An ammonia dehydrogenation catalyst was manufactured in the same manner as in Example 1, except that the molar ratio of nickel (Ni) to cerium (Ce) (Ni / Ce) (based on metal, not metal oxide) was adjusted to 1 in the ammonia dehydrogenation catalyst manufactured above.

[0050] Example 6: Preparation of a catalyst for ammonia dehydrogenation

[0051] An ammonia dehydrogenation catalyst was manufactured in the same manner as in Example 1, except that the molar ratio of nickel (Ni) to cerium (Ce) (based on metal, not metal oxide) was adjusted to 6 in the ammonia dehydrogenation catalyst manufactured above.

[0052] Example 7: Preparation of a catalyst for ammonia dehydrogenation

[0053] A catalyst for ammonia dehydrogenation was prepared in the same manner as in Example 1, except that lanthanum (La) was used instead of cerium (Ce).

[0054] Example 8: Preparation of a catalyst for ammonia dehydrogenation

[0055] A catalyst for ammonia dehydrogenation was prepared in the same manner as in Example 1, except that praseodymium (Pr) was used instead of cerium (Ce).

[0056] Example 9: Preparation of a catalyst for ammonia dehydrogenation

[0057] A catalyst for ammonia dehydrogenation was prepared in the same manner as in Example 1, except that neodymium (Nd) was used instead of cerium (Ce).

[0058] Example 10: Preparation of a catalyst for ammonia dehydrogenation

[0059] A catalyst for ammonia dehydrogenation was prepared in the same manner as in Example 1, except that samarium (Sm) was used instead of cerium (Ce).

[0060] Example 11: Preparation of a catalyst for ammonia dehydrogenation

[0061] A catalyst for ammonia dehydrogenation was prepared in the same manner as in Example 1, except that gadolinium (Gd) was used instead of cerium (Ce).

[0062] Example 12: Preparation of a catalyst for ammonia dehydrogenation

[0063] A catalyst for ammonia dehydrogenation was prepared in the same manner as in Example 1, except that terbium (Tb) was used instead of cerium (Ce).

[0064] Example 13: Preparation of a catalyst for ammonia dehydrogenation

[0065] A catalyst for ammonia dehydrogenation was prepared in the same manner as in Example 1, except that dysprosium (Dy) was used instead of cerium (Ce).

[0066] Example 14: Preparation of a catalyst for ammonia dehydrogenation

[0067] A catalyst for ammonia dehydrogenation was prepared in the same manner as in Example 1, except that holmium (Ho) was used instead of cerium (Ce).

[0068] Example 15: Preparation of a catalyst for ammonia dehydrogenation

[0069] A catalyst for ammonia dehydrogenation was prepared in the same manner as in Example 1, except that erbium (Er) was used instead of cerium (Ce).

[0070] Example 16: Preparation of a catalyst for ammonia dehydrogenation

[0071] A catalyst for ammonia dehydrogenation was prepared in the same manner as in Example 1, except that the same molar ratio of cerium (Ce) and lanthanone (La) was used instead of cerium (Ce).

[0072] Example 17: Preparation of a catalyst for ammonia dehydrogenation

[0073] A catalyst for ammonia dehydrogenation was prepared in the same manner as in Example 1, except that the same molar ratio of cerium (Ce) and praseodymium (Pr) was used instead of cerium (Ce).

[0074] Example 18: Preparation of a catalyst for ammonia dehydrogenation

[0075] A catalyst for ammonia dehydrogenation was prepared in the same manner as in Example 1, except that cerium (Ce), lanthanone (La), and praseodymium (Pr) were used in the same molar ratio instead of cerium (Ce).

[0076] Reference Example 1: Preparation of a catalyst for ammonia dehydrogenation

[0077] An ammonia dehydrogenation catalyst was manufactured in the same manner as in Example 1, except that the content of aluminum (Al) (based on metal, not metal oxide) in the manufactured ammonia dehydrogenation catalyst was adjusted to 0 parts by weight (i.e., based on 100 parts by weight of the manufactured ammonia dehydrogenation catalyst).

[0078] Reference Example 2: Preparation of a catalyst for ammonia dehydrogenation

[0079] An ammonia dehydrogenation catalyst was manufactured in the same manner as in Example 1, except that the content of aluminum (Al) (based on metal, not metal oxide) in the manufactured ammonia dehydrogenation catalyst was adjusted to 0.5 parts by weight (i.e., based on 100 parts by weight of the manufactured ammonia dehydrogenation catalyst).

[0080] Reference Example 3: Preparation of a catalyst for ammonia dehydrogenation

[0081] An ammonia dehydrogenation catalyst was manufactured in the same manner as in Example 1, except that the content of aluminum (Al) (based on metal, not metal oxide) in the manufactured ammonia dehydrogenation catalyst was adjusted to 9 parts by weight (i.e., based on 100 parts by weight of the manufactured ammonia dehydrogenation catalyst).

[0082] Reference Example 4: Preparation of a catalyst for ammonia dehydrogenation

[0083] An ammonia dehydrogenation catalyst was manufactured in the same manner as in Example 1, except that the molar ratio of nickel (Ni) to cerium (Ce) (Ni / Ce) (based on metal, not metal oxide) was adjusted to 0.5 in the ammonia dehydrogenation catalyst manufactured above.

[0084] Reference Example 5: Preparation of a catalyst for ammonia dehydrogenation

[0085] An ammonia dehydrogenation catalyst was manufactured in the same manner as in Example 1, except that the molar ratio of nickel (Ni) to cerium (Ce) (based on metal, not metal oxide) was adjusted to 8 in the ammonia dehydrogenation catalyst manufactured above.

[0086] The compositions of the catalysts manufactured in Examples 1 to 18 and Reference Examples 1 to 5 are summarized and shown in Table 1 below.

[0087] Aluminum (Al) content (parts by weight) (based on metal, not metal oxide, and based on 100 parts by weight of catalyst for ammonia dehydrogenation) Molar ratio of nickel (Ni) to lanthanide element (M) (Ni / M) (based on metal, not metal oxide) Example 122 Example 212 Example 362 Example 482 Example 521 Example 626 Example 722 Example 822 Example 922 Example 1022 Example 1122 Example 1222 Example 1322 Example 1422 Example 1522 Example 1622 Example 1722 Example 1822 Reference Example 102 Reference Example 20.52 Reference Example 392 Reference Example 420.5 Reference Example 528

[0088] Evaluation Example 1: Ammonia Conversion Rate Evaluation

[0089] The catalysts prepared in Examples 1 to 18 and Reference Examples 1 to 5 were activated by in-situ hydrogen treatment. Thereafter, the catalysts were activated under atmospheric pressure (1 atm), 400°C, and a space velocity of 1,500 hr. -1 After contacting the ammonia / helium mixture gas (5% NH3 / He) having an ammonia concentration of 5% by volume under the conditions of each catalyst, the ammonia conversion rate was evaluated according to the above mathematical formula 1, and the results are shown in Table 2 below.

[0090] Example 12345678 Ammonia conversion rate (%) 94.587.280.579.492.783.291.288.7 Example Ammonia conversion rate (%) 91011121314151685.184.681.281.879.581.082.192.9 Example Reference Example 171812345 Ammonia conversion rate (%) 89.791.155.865.968.269.169.7

[0091] Referring to Table 2 above, the catalysts manufactured in Examples 1 to 18 were found to have higher ammonia conversion rates than the catalysts manufactured in Reference Examples 1 to 5.

[0092] In addition, in this specification, an ammonia dehydrogenation catalyst was prepared by supporting only one to three types of lanthanide elements, and the activity (i.e., ammonia conversion rate) of the ammonia dehydrogenation catalyst thus prepared was evaluated. However, since all lanthanide elements have substantially the same characteristics, even when an ammonia dehydrogenation catalyst is prepared using a different combination of two or more lanthanide elements, substantially the same results as the data described in Table 2 can be obtained, which is obvious to a person having ordinary skill in the art.

[0093] While preferred embodiments of the present invention have been described above with reference to the examples, these are merely exemplary, and those skilled in the art will appreciate that various modifications and equivalent implementations are possible. Accordingly, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A catalyst for ammonia dehydrogenation comprising nickel (Ni), a lanthanide element (M), and aluminum (Al).

2. In paragraph 1, A catalyst for ammonia dehydrogenation, wherein the above lanthanide element (M) comprises La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu or a combination thereof.

3. In paragraph 1, An ammonia dehydrogenation catalyst wherein the content of the above aluminum (Al) is 1 to 8 parts by weight per 100 parts by weight of the above ammonia dehydrogenation catalyst.

4. In paragraph 1, A catalyst for ammonia dehydrogenation, wherein the molar ratio (Ni / M) of nickel (Ni) to the lanthanide element (M) is 1 to 6.

5. In paragraph 1, A catalyst for ammonia dehydrogenation, wherein the nickel (Ni), the lanthanide element (M), and the aluminum (Al) exist in the form of a mixed metal oxide.

6. In paragraph 1, 50~300m 2 A catalyst for ammonia dehydrogenation having a BET surface area of ​​ / g.

7. A method for producing hydrogen, comprising a step (S100) of contacting ammonia with an ammonia dehydrogenation catalyst according to any one of claims 1 to 6 to produce hydrogen.

8. In paragraph 7, The above step (S100) is a hydrogen production method performed at a temperature of 300°C to 700°C.

9. In paragraph 7, The above step (S100) is 500hr -1 25,000hr -1 A method for producing hydrogen performed at a space velocity of .

10. An air pollution prevention facility configured to remove ammonia by a catalytic reaction by contacting ammonia with an ammonia dehydrogenation catalyst according to any one of claims 1 to 6.