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AMMONIA SYNTHESIS CATALYST NEW

外国特許コード F210010596
整理番号 AF40-08WO
掲載日 2021年11月4日
出願国 世界知的所有権機関(WIPO)
国際出願番号 2021JP003257
国際公開番号 WO 2021153738
国際出願日 令和3年1月29日(2021.1.29)
国際公開日 令和3年8月5日(2021.8.5)
優先権データ
  • 特願2020-015552 (2020.1.31) JP
発明の名称 (英語) AMMONIA SYNTHESIS CATALYST NEW
発明の概要(英語) The present invention is a composite oxide which comprises an oxide of a metal element L and an oxide of a metal element N, has a composition represented by general formula (1), and has the properties (a) to (d). LnN1-n (1) (a) The metal element L comprises (i) a Group-1 element, (ii) a Group-2 element, or (iii) a Group-1 element and a Group-2 element; (b) the metal element N comprises a Group-1 or Group-2 element other than the metal element L; (c) n is 0.001 to 0.300 inclusive; and (d) the oxide of the metal element L and the oxide of the metal element N do not form a solid solution, and particles of the oxide of the metal element L are deposited on the surfaces of particles of the oxide of the metal element N. The present invention also provides: a metal-supported product in which particles M of at least one metal selected from the group consisting of cobalt, iron and nickel are supported on the composite oxide; and an ammonia synthesis catalyst.
従来技術、競合技術の概要(英語) BACKGROUND ART
Ammonia is an important raw material in modern chemical industries. 80% or more of the ammonia produced has been used to produce chemical fertilizers for cultivating. In addition, ammonia has attracted much attention as a carrier for energy and hydrogen. This is because (1) the hydrogen content thereof is high (17.6 wt%), (2) the energy density is high (12.8GJ/m3), and (3) carbon dioxide is not generated when decomposed to produce hydrogen. Being able to efficiently produce ammonia from renewable energy, such as solar energy and wind power, reduces global problems associated with energy and food hazards.
Currently, the Haber Bosch process used to produce ammonia consumes a large amount of energy, which accounts for about 1~ 2% of the worldwide energy consumption. In this way, about 60% of the energy consumed is recovered and ensured as the enthalpy of ammonia. However, most of the remaining energy is lost during the production of hydrogen from natural gas, during the synthesis of ammonia, and during the separation of gases. Ammonia synthesis by the Haber Bosch method is performed at a very high temperature (> 450 °C) and pressure (> 20 MPa), and thus a large amount of energy used in this method is required to be reduced. To reduce global energy consumption, there is a need for catalysts capable of synthesizing ammonia under milder conditions (lower temperatures and pressures) than iron-based catalysts used in the Haber Bosch process.
In recent years, methods for producing ammonia under low pressure conditions of approximately 1 MPa (10 atmospheres) have been known. Ruthenium catalysts used in ammonia production are generally supported on supports. For example, Patent Document 1 discloses that when a rare earth oxide is used as a support for supporting ruthenium, the amount of ruthenium used can be reduced and the reaction temperature can be lowered. However, in the method of producing ammonia of Patent Document 1, the yield of ammonia in the case of producing ammonia under lower pressure conditions is insufficient. Therefore, the present inventors developed a ruthenium catalyst including La0.5Ce0.5O1.75 reduced at 650 °C as a support, and reported that the ruthenium catalyst exhibits excellent properties even under low pressure conditions (Non-Patent Document 4).
Furthermore, the present inventors have developed a binary complex oxide including two types of metal elements and a metal-supported material (ammonia synthesis catalyst) in which a catalyst such as ruthenium is supported on the binary complex oxide (Patent Documents 5 and 6). As a catalyst for ammonia synthesis using a binary complex oxide (carrier) disclosed in this document, the following are disclosed.
Ru/Ce0.85La0.15Ox_ (500 °C, 600 °C, 650 °C, 700 °C) reduction, Ru/Ce0.67La0.33Ox_ (500 °C, 600 °C, 650 °C, 700 °C) reduction, Ru/Ce0.33La0.67Ox_ (500 °C, 600 °C, 650 °C, 700 °C) reduction; Ru/Ce0.15La0.85Ox_ (500 °C, 600 °C, 650 °C, 700 °C) reduction, Ru/Ce0.5La0.5Ox_ (500 °C, 650 °C, 800 °C) reduction, Ru/Ce0.5Zr0.5Ox_ 700 °C reduction, Ru/Ce0.5Pr0.5Ox_ (500 °C; 600 °C, 650 °C, 700 °C, 800 °C) reduction, Ru/La0.5Pr0.5Ox_ (450 °C, 500 °C, 600 °C, 650 °C, 700 °C) reduction, Ru/Ba0.1La0.9Ox_ (500 °C, 700 °C, 800 °C, 900 °C) reduction, Ru/Ba0.1Ce0. 9Ox_ (500 °C, 700 °C) reduction, Co/Ba0.05La0.95Ox_ (500 °C, 600 °C, 700 °C, 800 °C) reduction, Co/Ba0.01La0.99Ox_ 700 °C reduction, Co/Ba0.03La0.97Ox_ 700 °C reduction, Co/Ba0.1La0.9Ox_ 700 °C reduction.
Furthermore, this document also describes 8.4 wt% Ba/4.5wt% Ru/MgO_ (500 °C and 700 °C) reduction (Working Example 80 and Working Example 81). These oxides are obtained by impregnating MgO, which is a support with a Ru solution, calcining the impregnated MgO, and further supporting Ba using Ba (OH) 2 • 8H2O.
In addition to Patent Document 1 and Non-Patent Document 4, various Patent Documents disclose ammonia synthesis catalysts in which ruthenium is supported on various rare earth oxide supports. Exemplary examples include Patent Document 2~ 4 and Non-Patent Document 1~ 3. Patent Documents 2 and 4 disclose lanthanide oxides, Patent Document 3 discloses praseodymium oxide, and Non-Patent Document 1 discloses Ce oxide. Non-Patent Document 2 discloses a Ru/CeO2-La2O3 catalyst produced by co-precipitating a hydroxide of Ru, Ce, La, drying, and activating the catalyst.
Documents of the related art including Patent Document 1,2,4 and Non-Patent Document 1 describe that Ru is present as particles on the support surface of a ruthenium catalyst used in ammonia synthesis. When present as particles, the average diameter thereof is reported to be greater than 5 nm (see NpL 2) and less than 2 nm (NpL 4). Patent Document 3 describes that Ru has an egg shell structure. On the other hand, Non-Patent Document 3 discloses that Y (La)-M-O (M on which Ru is supported, when evaluating the ammonia synthesis activity of an Ca, Sr, Ba) catalyst, Regarding the support oxide prior to supporting the Ru, it is stated that the specific surface area was large when the calcination temperature of the support oxide was set to 450 °C, and the specific surface area was reduced when the calcination temperature was raised to 650 °C. In addition, in view of the fact that Ru is expensive, a catalyst for ammonia synthesis in which a transition metal compound other than Ru, for example, Co, is supported on a support has also been proposed (for example, see NpL 5 and NpL 6). However, Non-Patent Document 6 discloses Co-BaO/C in which cobalt is supported on barium oxide, but ammonia synthesis activity was low. Furthermore, in Non-Patent Document 5, calcium amide was used instead of oxide (Co/Ba-Ca (NH2) 2)), but the ammonia yield of the catalyst supporting Co at 1 MPa was not as high as that of the catalyst supporting Ru.
  • 出願人(英語)
  • ※2012年7月以前掲載分については米国以外のすべての指定国
  • JAPAN SCIENCE AND TECHNOLOGY AGENCY
  • 発明者(英語)
  • NAGAOKA Katsutoshi
  • OGURA Yuta
  • SATO Katsutoshi
  • MIYAHARA Shin-ichiro
国際特許分類(IPC)
指定国 National States: AE AG AL AM AO AT AU AZ BA BB BG BH BN BR BW BY BZ CA CH CL CN CO CR CU CZ DE DJ DK DM DO DZ EC EE EG ES FI GB GD GE GH GM GT HN HR HU ID IL IN IR IS IT JO JP KE KG KH KN KP KR KW KZ LA LC LK LR LS LU LY MA MD ME MG MK MN MW MX MY MZ NA NG NI NO NZ OM PA PE PG PH PL PT QA RO RS RU RW SA SC SD SE SG SK SL ST SV SY TH TJ TM TN TR TT TZ UA UG US UZ VC VN WS ZA ZM ZW
ARIPO: BW GH GM KE LR LS MW MZ NA RW SD SL SZ TZ UG ZM ZW
EAPO: AM AZ BY KG KZ RU TJ TM
EPO: AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR
OAPI: BF BJ CF CG CI CM GA GN GQ GW KM ML MR NE SN ST TD TG
参考情報 (研究プロジェクト等) CREST Creation of Innovative Core Technology for Manufacture and Use of Energy Carriers from Renewable Energy AREA
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