Catalysts and apparatus for synthesis gas production

Abstract

To provide a catalyst for producing synthesis gas that can suppress excessive heat generation during the reaction and has excellent heat resistance and durability Do. 【Solution means】 A catalyst for producing synthesis gas from hydrocarbons, which is represented by the following formula (1) and satisfies the following formula (2). M / A x B y O x+2y (1) [In formula (1), M is Pt or Rh, A is at least one element selected from divalent metal elements, B is at least one element selected from tetravalent metal elements, O is oxygen, and x is a real number satisfying 0 ≦ x ≦ 1, and y is a real number satisfying 0 < y ≦ 1.] R = S2 / (S1 + S2) ≦ 0.1 (2) [In formula (2), S1: Peak area derived from Linear-CO adsorbed on Pt particles or Rh particles in CO-DRIFTS measurement, S2: Peak area derived from Bridge-CO adsorbed on Pt particles or Rh particles in CO-DRIFTS measurement.]

Description

[Technical Field]

[0001] This invention relates to a catalyst for synthesis gas production and a synthesis gas production apparatus. [Background technology]

[0002] Synthesis gas is an important mixed gas that is used in a wide range of applications, not only as a raw material for basic chemicals such as methanol and liquid hydrocarbons, but also in the synthesis of various chemicals such as ammonia and oxo.

[0003] Known methods for producing synthesis gas include steam reforming of hydrocarbons (Patent Document 1, Non-Patent Document 1), dry reforming (Patent Document 2, Non-Patent Document 1), and autothermal reforming (Patent Document 3). Steam reforming and dry reforming are endothermic reactions, and therefore require fuel to be used to heat the reaction chamber to allow the reaction to proceed sufficiently. These processes typically produce synthesis gas while maintaining a temperature of 800°C or higher. Autothermal reforming, on the other hand, is a synthesis gas production process that reduces fuel consumption by adding oxygen to hydrocarbons to induce an exothermic reaction, and then using that heat to carry out steam reforming or dry reforming. The reaction chamber in autothermal reforming reaches temperatures of around 2000°C due to the exothermic reaction. As mentioned above, steam reforming and dry reforming are endothermic reactions that use large amounts of fuel, resulting in high greenhouse gas (GHG) emissions and a significant environmental burden. On the other hand, autothermal reforming is an exothermic reaction that reaches temperatures of around 2000°C, raising concerns about the durability (heat resistance) of the catalysts used, as well as requiring expensive refractory materials for the reactor, which presents problems from an economic standpoint.

[0004] As a method for producing syngas, a catalytic partial oxidation reaction (CPOx) process (Non-Patent Document 2) that directly supplies hydrocarbons and oxygen to a catalyst layer has also been proposed and studied. The CPOx process utilizes a catalyst for the oxidation of hydrocarbons and is expected to start the reaction under mild conditions and control the heat generation rate, thereby controlling the temperature distribution inside the reactor without external heat supply. As a result, it is possible to reduce the environmental impact and the cost of the reactor.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document  2

Patent Document 3

Non-Patent Documents

[0006]

Non-Patent Document 1

Non-Patent Document 2

[0007] However, the CPOx process suffers from the problem of excessive temperature unevenness (hot spots) in the catalyst layer. A catalytic process that can suppress these hot spots while simultaneously achieving high heat resistance and durability of the catalyst has not yet been industrialized.

[0008] This invention was made to solve the above-mentioned problems, and aims to provide a catalyst for synthesis gas production that can suppress hot spots and has excellent heat resistance and durability. [Means for solving the problem]

[0009] In order to solve the above problems, the present inventors conducted diligent research and found that the above problems can be solved by using a catalyst in which platinum or rhodium is supported on a specific metal oxide. That is, the present invention is as follows.

[0010] [1] A catalyst for producing synthesis gas containing carbon monoxide and hydrogen from hydrocarbons, which is represented by the following formula (1) and satisfies the following formula (2). M / A x B y O x+2y (1) [In equation (1), M is either Pt or Rh. A is at least one element selected from divalent metal elements, B is at least one element selected from tetravalent metal elements, O is oxygen, x is a real number satisfying 0 ≦ x ≦ 1, y is a real number satisfying 0 < y ≦ 1. R = S2 / (S1 + S2) ≦ 0.1 (2) [In formula (2), S1: The peak area of Linear-CO adsorbed on Pt particles or Rh particles in CO-DRIFTS measurement. S2: The peak area of Bridge-CO adsorbed on Pt particles or Rh particles in CO-DRIFTS measurement. [2] The catalyst according to [1] above, wherein in formula (1), A is at least one element selected from the group consisting of Ca, Sr, and Ba. [3] The catalyst according to [1] or [2] above, wherein in formula (1), B is at least one element selected from the group consisting of Zr and Ti. [4] The catalyst according to any one of [1] to [3] above, wherein in formula (1), when x = 0, B is Zr. [5] The catalyst according to any one of [1] to [4] above, wherein the supported amount of Pt or Rh is less than 1% by mass. [6] The catalyst according to any one of [1] to [5] above, wherein M in formula (1) is Pt, and in formula (2), R ≦ 0.09. [7] The catalyst according to any one of [1] to [6] above, wherein M in formula (1) is Pt, and in formula (2), R ≦ 0.040. [8] The catalyst according to any one of [1] to [5] above, wherein M in formula (1) is Rh, and in formula (2), 0.01 ≦ R ≦ 0.1. [9] A synthesis gas production apparatus comprising a reactor through which a gas to be treated containing at least hydrocarbons flows, and a catalyst disposed at a position where the gas to be treated contacts inside the reactor, wherein the catalyst is the catalyst according to any one of [1] to [8] above.

Advantages of the Invention

[0011] Since the catalyst of the present invention has high activity, by starting the oxidation (combustion) of hydrocarbons, which is an exothermic reaction, from a low temperature, an excessive bias in the temperature distribution (hot spot) can be suppressed, and since it has excellent heat resistance and durability, the ability to produce synthesis gas at high temperatures can be maintained.

[0012] Hereinafter, embodiments of the present invention (hereinafter, may also be referred to as "the present embodiments") will be described in detail. However, the following description is an example of the embodiments of the present invention, and the present invention is not limited to these contents at all.

[0013] One embodiment of the present invention relates to a catalyst for producing synthesis gas containing carbon monoxide and hydrogen from hydrocarbons, and relates to a catalyst represented by the following general formula (1). M / A x B y O x+2y (1)

[0014] In the above general formula, M is Pt or Rh, A is at least one element selected from the group consisting of divalent metal elements, B is at least one element selected from the group consisting of tetravalent metal elements, O is oxygen, x is a real number satisfying 0 ≦ x ≦ 1, and y is a real number satisfying 0 < y ≦ 1. That is, the catalyst represented by the general formula (1) is a platinum-supported metal oxide catalyst (hereinafter, may also be simply abbreviated as "Pt-supported catalyst") or a rhodium-supported metal oxide catalyst (hereinafter, may also be simply abbreviated as "Rh-supported catalyst") in which platinum or rhodium is supported on a metal oxide carrier [A x B y O x+2y 〔A x B y O x+2y 〕 〔A x B​​​​​y O x+2y represents a metal oxide and serves as a carrier supporting platinum or rhodium. A is not particularly limited as long as it is at least one element selected from the group consisting of divalent metal elements (hereinafter, may be abbreviated as A element). An element of Group 2 of the periodic table can be selected as the A element. As is clear from the definition, the A element may be a single kind or two or more kinds. The A element is preferably an alkaline earth metal. As the A element, at least one is preferably selected from the group consisting of Ca, Sr, and Ba, and more preferably at least one is selected from the group consisting of Sr and Ba. In one aspect of this embodiment, the A element is preferably Sr.

[0016] B is not particularly limited as long as it is at least one element selected from the group consisting of tetravalent metal elements (hereinafter, may be abbreviated as B element). An element of Group 4 of the periodic table can be selected as the B element. As is clear from the definition, the B element may be a single kind or two or more kinds. The B element is preferably at least one selected from Ti and Zr. In one aspect of this embodiment, the B element is preferably Zr.

[0017] x is a real number satisfying 0 ≦ x ≦ 1, and y is a real number satisfying 0 < y ≦ 1. When the lower limit value of x exceeds 0, it becomes a composite metal oxide. When x is 0, if one kind is selected alone as the B element, it becomes a single metal oxide, and if two or more kinds are selected in combination as the B element, it becomes a composite metal oxide. According to one aspect of this embodiment, when x is 0, it is preferably a single metal oxide in which one kind is selected as the B element. That is, the carrier [A x B y O x+2y may be a composite metal oxide, a single metal oxide, or a mixture thereof, and can be appropriately selected according to the metal elements actually applied.

[0018] [A x B y Ox+2y When ] is a composite metal oxide, elements A and B can be any combination as described above, but combinations selected from the group consisting of Ca-Ti, Ca-Zr, Sr-Ti, Sr-Zr, Ba-Ti, and Ba-Zr are preferred.

[0019] For example, if Zr is selected as element B, it may be zirconia, which is a single metal oxide where x is 0, or a composite metal oxide where the lower limit of x is greater than 0. In the case of a composite metal oxide, as mentioned above, examples include combinations such as Ca-Zr, Sr-Zr, and Ba-Zr. According to one aspect of the present invention, element B is Zr and a single metal oxide where x is 0 is more preferable. Alternatively, if element B is Zr and it is a composite metal oxide, a combination of Ca-Zr or Sr-Zr is preferred, and a combination of Sr-Zr is more preferable.

[0020] When designing the catalyst of this embodiment, the metal oxide that serves as the support [A x B y O x+2y If the material is a complex oxide, the electronegativity of element A constituting the support is also one factor that can enhance catalytic activity. Designing the material to have low electronegativity of element A improves electron donation from the support to platinum or rhodium, which can further improve catalytic activity for hydrocarbon combustion and contribute to lowering the combustion initiation temperature. Designing the material to have high electronegativity of element A reduces electron donation from the support to platinum or rhodium, which weakens the back donation of electrons to the product carbon monoxide, promotes desorption, and can contribute to improving synthesis gas production capacity.

[0021] [A x B y O x+2y The BET specific surface area of ​​a metal oxide represented by [ ] is not particularly limited, and is usually 0.1 m². 2 / g or more, preferably 0.5m 2 / g or more, comfortably 1m 2 / g or more, usually 200m 2 Less than or equal to / g, preferably 100m 2 / g or less, more preferably 50m 2 / g or less, more preferably 20m 2 It is less than / g. The specific surface area of ​​BET is 0.1m². 2 By increasing the amount to over / g, the dispersibility of the supported platinum, which is the active site, can be improved, which can contribute to improving the synthesis gas production capacity. BET specific surface area is 200m² 2 By reducing the amount to less than / g, hot spots caused by excessive combustion can be suppressed.

[0022] [Platinum (Pt) supported catalyst / Rhodium (Rh) supported catalyst] The Pt-supported catalyst or Rh-supported catalyst of this embodiment is, as described above, a metal oxide [A x B y O x+2y This is a material in which platinum or rhodium is supported on a carrier. The Pt-supported catalyst or Rh-supported catalyst of this embodiment is suitable for catalytic partial oxidation (CPOx) reactions. The Pt-supported catalyst or Rh-supported catalyst of this embodiment functions as a catalyst for synthesis gas production in a multi-stage reaction, which includes (i) a step of reacting hydrocarbons with oxygen to produce hydrocarbons, carbon dioxide (CO2), and water (H2O) (hydrocarbon combustion step), and (ii) a hydrocarbon reforming step of reacting hydrocarbons, CO2, and H2O to produce carbon monoxide (CO) and hydrogen (H2).

[0023] The hydrocarbon combustion process (i) is an exothermic reaction, while the hydrocarbon reforming process (ii) is an endothermic reaction. In the hydrocarbon combustion process (i), the rapid heat generation associated with the combustion of hydrocarbons, known as the formation of hot spots, is a problem. The formation of such hot spots can lead to catalyst degradation and catalyst deactivation. Since the hydrocarbon reforming process (ii) is an equilibrium reaction, it is preferable to reach the maximum equilibrium state in which synthesis gas (CO and H2) is produced at the set process temperature. The Pt-supported catalyst or Rh-supported catalyst of this embodiment is placed in an oxidizing atmosphere in step (i) and in a reducing atmosphere in step (ii), but it exhibits good catalytic activity in both steps and can withstand fluctuations in the redox atmosphere.

[0024] The catalytic activity in each step (i) and (ii) can be determined and confirmed by various methods. In this specification, the following criteria were considered for determining catalytic activity in each step. For step (i), the temperature (T50) at which the oxygen addition rate (hereinafter sometimes abbreviated as O2 addition rate), which is a raw material for the hydrocarbon combustion reaction, reaches 50% is used as the standard. A lower T50 is preferable because it results in superior combustion performance at low temperatures. T50 is preferably 600°C or lower, more preferably 550°C or lower, even more preferably 350°C or lower, and even more preferably 300°C or lower. A T50 within the above range indicates that the catalyst has excellent catalytic activity, allowing the hydrocarbon combustion reaction to proceed at low temperatures. A lower T50 allows the reaction to start at a lower temperature, lowering the maximum temperature reached in the reactor's temperature distribution, thereby improving the catalyst's durability and enabling it to exhibit excellent catalytic activity in the subsequent hydrocarbon reforming step (ii). Furthermore, by suppressing excessive heat generation, expensive refractory materials (such as bricks) around the reactor become unnecessary, allowing for the design of a less expensive process.

[0025] For process (ii), the ratio of the actual yield of the products CO and H2 to the equilibrium yield (actual yield / equilibrium yield) at the furnace temperature set in the reaction design is used as the standard, and this ratio is called the "equilibrium attainment level." From the above definition, a high equilibrium attainment level is desirable. The reason for this is that in process (ii), which is an endothermic reaction, the equilibrium yield is equivalent to the maximum yield value under any reaction conditions, and the actual yield is equal to the ratio of the equilibrium yield to the actual yield. Therefore, a high ratio indicates a high synthesis gas production capacity at high temperatures. Since the catalyst of this embodiment has high catalytic activity for synthesis gas production at high temperatures, it is clear that it also has excellent heat resistance. For both CO and H2, the equilibrium level is preferably 0.4 or higher, more preferably 0.5 or higher, even more preferably 0.7 or higher, and even more preferably 0.8 or higher. Achieving an equilibrium level within this range indicates excellent catalytic activity that enhances synthesis gas production at high temperatures.

[0026] In this embodiment, by supporting platinum or rhodium on the catalyst, excessive heat generation in step (i) can be suppressed, leading to the suppression of hot spots.

[0027] [Platinum (Pt)] The average particle size of the supported platinum particles is not particularly limited as long as it does not impair the effects of the present invention. However, the inventors have found that the larger the average particle size of the platinum particles, the greater the tendency for the value of S2 in equation (2) described later to increase. When comparing with the same amount of supported material, the larger the average particle size of the platinum particles, the higher the proportion of particles that are aligned with each other. This increases the tendency for carbon monoxide to be adsorbed as a bridge on two platinum atoms, as shown by S2, and this becomes one of the factors that reduces catalytic activity, as described later. It was found that the tendency for S2 to increase is significantly observed when the average particle size of the platinum particles is greater than 2 nm.

[0028] From the above, the average particle size of the platinum particles is preferably 10 nm or less, more preferably 8 nm, even more preferably 5 nm or less, even more preferably 2 nm or less, even more preferably 1.9 nm or less, particularly preferably 1.7 nm or less, and most preferably 1.5 nm or less. The lower limit of the average particle size of the platinum particles is about 1.0 nm from the viewpoint of platinum particle stability and adjustment of the amount of supported platinum. If the size of the supported platinum particles is 2 nm or less, high catalytic activity can be maintained.

[0029] [Rhodium (Rh)] The average particle size of the supported rhodium particles is not particularly limited as long as it does not impair the effects of the present invention. However, the inventors have found that the larger the average particle size of the rhodium particles, the greater the tendency for the value of S2 in equation (2) described later to increase. When comparing with the same loading amount, the larger the average particle size of the rhodium particles, the higher the proportion of particles that are aligned with each other. This increases the tendency for carbon monoxide to be adsorbed as a bridge on two rhodium atoms, as shown by S2, and this becomes one of the factors that reduces catalytic activity, as described later. It was found that the tendency for S2 to increase is significantly observed when the average particle size of the rhodium particles is greater than 2 nm.

[0030] From the above, the average particle size of the rhodium particles is preferably 10 nm or less, more preferably 8 nm or less, even more preferably 5 nm or less, even more preferably 2 nm or less, even more preferably 1.9 nm or less, particularly preferably 1.7 nm or less, and most preferably 1.5 nm or less. The lower limit of the average particle size of the rhodium particles is about 1.0 nm from the viewpoint of rhodium particle stability and adjustment of the supported amount. If the size of the supported rhodium particles is 2 nm or less, high catalytic activity can be maintained.

[0031] The "average particle diameter" mentioned above can be measured using a transmission electron microscope (TEM). Fifty platinum or rhodium particles are randomly selected from the TEM image of the platinum or rhodium particles. For each of the 50 selected particles, the major axis (the length of the longest straight line when connecting one end of the particle to the other) is measured, and the arithmetic mean of the measured major axes of the 50 particles is defined as the "average particle diameter." The platinum or rhodium particles to be measured are the smallest particles (primary particles) in which no grain boundaries can be observed. The average particle size of platinum or rhodium particles can be measured by TEM, and if it falls below the TEM's measurement limit, it means that the platinum or rhodium particles have a suitable particle size.

[0032] The amount of platinum or rhodium supported in the catalyst of this embodiment is not particularly limited as long as it does not impair the effects of the present invention, but is preferably less than 1% by mass, more preferably 0.9% by mass or less, even more preferably 0.7% by mass or less, even more preferably 0.5% by mass or less, and even more preferably 0.4% by mass or less. The lower limit of the amount of platinum or rhodium supported is not particularly limited, but from the viewpoint of maintaining excellent catalytic activity, it is preferably about 0.05% by mass, and more preferably about 0.1% by mass.

[0033] [S2 / (S1+S2)] In this embodiment, the Pt-supported catalyst or Rh-supported catalyst must satisfy the requirements of the following formula (2). R = S² / (S1+S²) ≤ 0.1 (2)

[0034] In equation (2), S1 is the peak area derived from Linear-CO adsorbed on Pt or Rh particles in CO-DRIFTS measurement, and S2 is the peak area derived from Bridge-CO adsorbed on Pt or Rh particles in CO-DRIFTS measurement. "CO-DRIFTS measurement" means measuring the CO spectrum on a Pt-supported catalyst or an Rh-supported catalyst by diffuse reflectance FT-IR spectroscopy (DRIFTS). "Linear-CO" means that carbon monoxide is adsorbed linearly (single-phase) on one platinum atom or rhodium atom, while "Bridge-CO" means that carbon monoxide is adsorbed in a bridge configuration on two platinum atoms or rhodium atoms. The conditions for DRIFTS measurement described in the examples can be used.

[0035] If the value of R in equation (2) is greater than 0.1, it is not possible to achieve both excellent catalytic activity in hydrocarbon combustion in step (i) and excellent catalytic activity in hydrocarbon reforming in step (ii). Metal oxide [A x B y O x+2y In the design of the support, although the trend differs depending on the elements A and B selected, it is not always possible to achieve both, and depending on the selected support, the T50 temperature in process (i) becomes high, making it difficult to suppress hot spots, and consequently the catalytic activity in hydrocarbon reforming in the subsequent process (ii) also decreases. Depending on the selected support, a relatively low T50 can be achieved, and even if the catalytic activity in process (i) is good, the catalytic activity in hydrocarbon reforming in the subsequent process (ii) may decrease.

[0036] The mechanism by which the above trend is obtained based on the value of R in equation (2) has not been identified, but the following phenomenon is considered to be one of the causes. A low R, that is, a low S2 value, means that the proportion of carbon monoxide bridging and adsorbing on two or more platinum atoms or rhodium atoms is low. When carbon monoxide desorbs from the bridging site, it is necessary to dissociate two or more Pt-C bonds or Rh-C bonds, and desorption of carbon monoxide is more difficult compared to linear sites where only one Pt-C bond or Rh-C bond can be dissociated, so this is considered to be one of the causes related to catalytic activity.

[0037] The researchers investigated methods to control the value of R shown in equation (2), and found that, for example, (a) the size of the supported platinum or rhodium particles, (b) the amount of platinum supported in the Pt-supported catalyst, or the amount of rhodium supported in the Rh-supported catalyst, and (c) the amount of platinum or rhodium and the metal oxide that serves as the support [A x B y O x+2y We found that the value of R can be controlled by combining it with (d) the calcination temperature and atmosphere during the preparation of the Pt-supported catalyst or Rh-supported catalyst, etc.

[0038] The R value of the Pt catalyst represented by formula (2) is preferably 0.09 or less, more preferably 0.08 or less, even more preferably 0.05 or less, and even more preferably 0.040 or less, and may be 0. That is, this includes cases in which carbon monoxide is not adsorbed by bridging on the platinum atoms. Note that R=0, or "zero peak area originating from Bridge-CO adsorbed on Pt or Rh particles in CO-DRIFTS measurement," means that there are no peaks that can be clearly identified as originating from Bridge-CO.

[0039] The upper limit of R in the Rh catalyst shown in formula (2) is preferably 0.1 or less, more preferably 0.09 or less, and even more preferably 0.08 or less, and may be 0. That is, this includes the case in which carbon monoxide is not adsorbed by bridging on the rhodium atom. The meaning of R=0 is as described above. The lower limit of R in the Rh catalyst represented by formula (2) is preferably 0.01 or higher, more preferably 0.02 or higher, even more preferably 0.03 or higher, even more preferably 0.04 or higher, and even more preferably 0.05 or higher, and may also be 0.06 or higher. In one embodiment of the present invention, the R value of the Rh catalyst represented by formula (2) is preferably 0 ≤ R ≤ 0.1, and more preferably 0.01 ≤ R ≤ 0.1.

[0040] As described above, the Pt-supported catalyst or Rh-supported catalyst of this embodiment exhibits excellent catalytic activity in both (i) the hydrocarbon combustion step and (ii) the hydrocarbon reforming step in the catalytic partial oxidation (CPOx) reaction. Specifically, it can suppress hot spots, has excellent durability, and also has excellent heat resistance. The Pt-supported catalyst or Rh-supported catalyst of this embodiment can be used in a catalytic partial oxidation (CPOx) reaction having (i) a hydrocarbon combustion step and (ii) a hydrocarbon reforming step. Therefore, it is not necessary to supply heat from an external source during synthesis gas production, thereby suppressing GHG emissions and reducing the environmental burden. Furthermore, the reaction heat generated by the oxidation of the raw hydrocarbons can be efficiently utilized in the reforming reaction, improving process efficiency.

[0041] [Method for producing synthesis gas] One embodiment of a method for producing synthesis gas using the Pt-supported catalyst or Rh-supported catalyst of this embodiment will be described. The method for producing synthesis gas of this embodiment comprises at least (i) a hydrocarbon combustion step and (ii) a hydrocarbon reforming step. As a synthesis gas production method having steps (i) and (ii) described above, a known gas-phase reaction process can be applied. The reaction may be carried out in batch, semi-continuous, or continuous form, but steps (i) and (ii) are preferably carried out continuously.

[0042] [Step (i)] Step (i) is a hydrocarbon combustion step in which hydrocarbons and oxygen are brought into contact with the Pt-supported catalyst or Rh-supported catalyst. The reaction mode of step (i) is not particularly limited as long as the hydrocarbons and oxygen are in the gas phase in the reaction region.

[0043] [Hydrogen] Examples of hydrocarbons that can be used in this embodiment include those mainly composed of natural gas (mainly methane and ethane), biogas (mainly methane, and may contain sulfur compounds, nitrogen, or nitrogen compounds as impurities), and liquefied petroleum gas (mainly propane), but those mainly composed of methane are particularly preferred. Methane (CH4) has a hydrogen / carbon ratio of 4, which is the largest hydrogen / carbon ratio among hydrocarbon compounds. In synthesis gas production reactions, it is known that when the hydrogen / carbon ratio is small, carbon deposition becomes advantageous due to thermodynamic equilibrium. By using methane as the hydrocarbon, it is possible to suppress carbon deposition on the catalyst and thus suppress catalyst degradation.

[0044] In a hydrocarbon gas mainly composed of methane, the methane content may be preferably 20% by mass or more, more preferably 50% by mass or more, and even more preferably 80% by mass or more, based on the total mass of the hydrocarbons, and methane may be 100% by mass. According to one aspect of this embodiment, it is preferable to use methane as the hydrocarbon, and the above-mentioned Pt-supported catalyst or Rh-supported catalyst can be used as a methane reforming catalyst.

[0045] [Diluent] In addition to hydrocarbons and oxygen, helium, argon, nitrogen, carbon monoxide, carbon dioxide, hydrogen, water, paraffins, aromatic compounds, and mixtures thereof can also be used as diluents. Among these, the presence of at least one of water (water vapor), nitrogen, and carbon dioxide is preferable because it can suppress excessive heat generation in step (i). As a diluent, the impurities contained in the reaction raw materials may be used as is, or a separately prepared diluent may be used. The diluent may be mixed with the reaction raw materials before being placed in the reactor, or it may be supplied to the reactor separately from the reaction raw materials.

[0046] As an example of the supply ratio in process (i), a raw material supply ratio of 5-35 mol% methane, 5-25 mol% oxygen, 5-35 mol% water (diluent), and the remainder being carbon dioxide (diluent) can be given.

[0047] Since step (i) is an exothermic reaction, a temperature distribution occurs within the catalyst layer. The lower limit of the maximum temperature that the catalyst layer can reach is usually about 500°C or higher, preferably 600°C or higher, and the upper limit of the maximum temperature that the catalyst layer can reach is usually 1400°C or lower, preferably 1200°C or lower, more preferably 1000°C or lower, and most preferably 800°C or lower. A maximum temperature of 500°C or higher is preferable because it provides sufficient heat to carry out the reaction in the subsequent step (ii). On the other hand, a maximum temperature of 1400°C or lower is preferable because it prevents catalyst sintering and allows the reaction in step (ii) to proceed sufficiently, and a temperature of 1200°C or lower is preferable because it eliminates the need for expensive refractory materials in the reactor, thus reducing reactor costs.

[0048] [Step (ii)] After all the oxygen used as a raw material in step (i) is consumed, the hydrocarbon reforming step (ii) follows. Using the reaction heat generated by the oxidation of hydrocarbons in step (i), the hydrocarbons, carbon dioxide, and water present in the system are reacted to synthesize carbon monoxide and hydrogen.

[0049] The lower limit of the maximum temperature reached in the catalyst layer in step (ii) is usually about 500°C or higher, preferably 600°C or higher, and the upper limit of the maximum temperature reached in the catalyst layer is usually 1400°C or lower, preferably 1200°C or lower, more preferably 1000°C or lower, and most preferably 800°C or lower. A maximum temperature of 500°C or higher in the catalyst layer is preferable because it increases the reaction rate, improves the degree of equilibrium attainment as described above, and provides sufficient synthesis gas. A maximum temperature of 1400°C or lower in the catalyst layer is preferable because it prevents catalyst sintering and allows the reaction to proceed sufficiently, and a temperature of 1200°C or lower is preferable because it eliminates the need for expensive refractory materials in the reactor, thus reducing reactor costs.

[0050] Step (ii) is an endothermic reaction, and the product distribution when equilibrium is reached strongly depends on the reactor outlet temperature. The reactor outlet temperature is usually about 500°C or higher, preferably 600°C or higher, and the upper limit of the reactor outlet temperature is usually 1400°C or lower, preferably 1200°C or lower, more preferably 1000°C or lower, and most preferably 800°C or lower. A reactor outlet temperature of 500°C or higher is preferable because it is advantageous for product formation according to Le Chatelier's principle. A reactor outlet temperature of 1400°C or lower is preferable because it can prevent catalyst sintering and allow the reaction to proceed sufficiently, and a temperature of 1200°C or lower is preferable because it eliminates the need for expensive refractory materials in the reactor, thus reducing reactor costs.

[0051] [Synthesis gas production equipment] The synthesis gas production apparatus used in this embodiment comprises a reactor through which a gas to be treated, containing at least hydrocarbons, flows, and a catalyst positioned inside the reactor at a location in contact with the gas to be treated. The catalyst used is the Pt-supported catalyst or Rh-supported catalyst of this embodiment described above. The shape of the reactor is not particularly limited, but it is preferably tubular since steps (i) and (ii) are carried out in succession. In this embodiment, the heat generated in step (i) can be used directly in step (ii), resulting in excellent energy efficiency. A synthesis gas production apparatus equipped with a reactor can be a fluidized bed reactor, a moving bed reactor, or a fixed bed reactor. A fixed bed reactor offers advantages in terms of equipment costs (including ancillary equipment), catalyst costs, and operational management.

[0052] Synthesis gas production may be carried out in batch, semi-continuous, or continuous form, but continuous production is preferred. In the case of continuous production, a single reactor may be used, or multiple reactors arranged in series or parallel may be used. For example, steps (i) and (ii) may be carried out separately or continuously, and can be carried out in the same reactor whether continuously or separately. When carried out continuously or in the same reactor, it is preferable to operate under conditions that are within the wider operating range of each step. In one embodiment of this product, it is preferable from the viewpoint of manufacturing efficiency to carry out steps (i) and (ii) in a continuous manner, and it is preferable to use a single reactor as the synthesis gas production apparatus.

[0053] When filling a fixed-bed reactor with the Pt-supported catalyst or Rh-supported catalyst of this embodiment, in order to minimize the temperature distribution of the catalyst layer, reaction-inert granular material such as quartz sand, alumina, silica, or silica-alumina may be mixed with the catalyst before filling. In this case, there are no particular restrictions on the amount of reaction-inert granular material such as quartz sand used. From the standpoint of uniform mixing with the catalyst, it is preferable that the particle size of this granular material is similar to that of the catalyst. The reaction substrate (reaction raw material) may be supplied to the above reactor in divided portions for the purpose of dispersing the heat generated by the reaction.

[0054] [Reaction conditions] The following describes an example of suitable reaction conditions for synthesis gas production. When carried out in a batch process, the C / O2 ratio and reaction start temperature described later are conditions for process (i), but all other conditions can be applied to both process (i) and process (ii). When carried out in a continuous process, these conditions are applied as the overall reaction conditions.

[0055] The ratio of hydrocarbons to oxygen supplied to the reactor is not particularly limited, but from the viewpoint of hydrocarbon combustion efficiency and safety, the molar ratio of hydrocarbons to oxygen (C / O2) is preferably 0.2 to 5.0, more preferably 0.5 to 3.0, and even more preferably 0.7 to 2.5.

[0056] The weight-to-space velocity (WHSV) of the reaction raw materials is preferably 0.1 hr. -1 Above, a more comfortable 0.5 hours -1 More preferably 0.7hr -1 That concludes the explanation. On the other hand, the gravitational space velocity is preferably 10hr. -1 More conveniently, 5hr -1 More preferably, 3 hours -1 The following is true: A gravitational space velocity within this range is advantageous for synthesis gas production.

[0057] The reaction initiation temperature (catalyst inlet temperature) is not particularly limited as long as partial oxidation of hydrocarbons is possible, but is usually 0°C or higher, preferably 100°C or higher. The upper limit of the reaction initiation temperature is 800°C or lower, preferably 500°C or lower, and more preferably 300°C or lower. A reaction initiation temperature of 0°C or higher is preferable because it increases the reaction rate in step (i) and generates sufficient heat to carry out the reaction in the subsequent step (ii). A reaction initiation temperature of 800°C or lower is preferable because it reduces the energy required for preheating and suppresses the maximum temperature reached in the catalyst layer.

[0058] In the production of synthesis gas, the upper limit of the reaction pressure during the reaction is preferably 3 MPa (absolute pressure, the same applies hereinafter) or less, and more preferably less than 1 MPa. A reaction pressure of 3 MPa or less suppresses the formation of undesirable by-products. Furthermore, a reaction pressure of 3 MPa or less allows for a lower reactor design pressure, thereby reducing construction costs. A reaction pressure of less than 1 MPa exempts the reactor from the High-Pressure Gas Safety Act, significantly reducing construction costs.

[0059] The lower limit of the reaction pressure is not particularly limited, but it is usually 0.1 kPa or higher, preferably 1 kPa or higher, and more preferably 10 kPa or higher. A sufficient reaction rate can be obtained by keeping the pressure above these lower limits.

[0060] According to this embodiment, synthesis gas (CO + H2) can be obtained as the final reaction product. The selectivity of carbon dioxide in the product can be 40.0% or less, allowing for more selective production of the above synthesis gas. In this embodiment, the conversion rate of hydrocarbons is 50-100%, the selectivity of carbon monoxide is 60-100%, and the selectivity of hydrogen is 60-100%. The mixed gas containing unreacted raw materials, by-products, and diluents at the reactor outlet can be introduced into known separation and purification equipment and treated for recovery, purification, recycling, or discharge according to each component.

[0061] [Method for preparing Pt-supported catalyst or Rh-supported catalyst] One example of a method for preparing the Pt-supported catalyst or Rh-supported catalyst of this embodiment is the following preparation method.

[0062] [Method for preparing the carrier] In this embodiment, the method for preparing the carrier is not particularly limited, and complex polymerization, solid-phase polymerization, sol-gel polymerization, hydrothermal synthesis, etc., can be used as appropriate. In one embodiment of this model, solid-phase polymerization or complex polymerization is preferably employed.

[0063] In solid-phase or complex polymerization methods, a metal oxide (in powder form) can be obtained as a support by mixing powders of element A-containing compounds (e.g., alkaline earth metal-containing compounds) and element B-containing compounds (e.g., Ti or Zr-containing compounds) as starting materials and performing a calcination treatment. Examples of the above-mentioned A-element-containing compounds and B-element-containing compounds include carbonates, halides, nitrates, hydroxides, oxides, and alkoxides. Among these, oxides are preferred because they suppress the formation of impurity phases and can be synthesized at low temperatures.

[0064] The support material may contain trace amounts of impurity elements. For example, typical elements and transition metal elements can be used as impurity elements, but typical elements and 3d transition metal elements are particularly preferred. These impurities contribute to improved catalytic activity by altering the electronic structure of the valence band and conduction band. The impurity content is preferably 5% by mass or less. Preferably, the impurity content is 1% by mass or less, and more preferably 0.1% by mass or less. When the impurity content is within the above range, the selectivity of the reaction is improved.

[0065] The solid-phase method and the complex polymerization method will be described in detail below. Here, the same preparation conditions can be used whether x=0 and one element B is selected as a single metal oxide, or whether x is greater than 0 and it is a complex metal oxide.

[0066] [Solid phase method] Generally, when synthesizing using the solid-phase method, the compositional distribution of each element tends to be uneven at the precursor stage and the post-calcination stage. Therefore, it is preferable to control the particle size of the raw material powder and ensure uniform mixing of the powder. For example, using raw material powder with small particle size and low aggregation, and mixing using a ball mill or the like are effective methods.

[0067] [Complex polymerization legal] In the complex polymerization method, the raw material powder is dissolved in a solvent as a starting material, a ligand is added, and the mixture is stirred at around 25°C (room temperature) or under heating to obtain a metal complex as a precursor. This obtained precursor is heated and organic matter is burned to obtain a complex oxide (in powder form). From the viewpoint of controlling the composition of the product, the raw materials are more preferably carbonates, halides, sulfates, acetates, and nitrates, and particularly preferably nitrates. This is because when the metal-containing raw materials are these salts, the by-products associated with the production of the complex oxide are gases or water containing nitrogen, oxygen, chlorine, carbon, sulfur, etc., which can be easily removed from the system. Ligands that can be used include ammonia, amines, pyridines, azides, imidazoles, hydrazines, nitrososides, isonitriles, aniline, isocyanates, nitriles, carboxylic acids, hydroxosides, carbamates, phosphonates, ethers, formyl, sulfides, thioates, thiocyanates, phosphines, phospides, cyanides, and carbenes. Both monodentate and polydentate ligands can be used. Among these, citric acid is preferred due to its low cost and low environmental impact.

[0068] In both the solid-phase method and the complex polymerization method, the calcination temperature and calcination time are not particularly limited as long as the catalyst of this embodiment can be obtained. From the viewpoint of reducing impurity phases, it is preferable that the calcination temperature and calcination time are such that the target phase is formed as the main phase or a single phase. By having the target phase as the main phase or a single phase, it is possible to suppress the decrease in oxygen permeation rate and the decrease in molded product strength caused by impurity phases. The firing temperature is preferably 800 to 1400°C, more preferably 900 to 1200°C. If the firing temperature is 800°C or higher, perovskite-type metal oxides are mainly obtained, and the formation of non-perovskite-type phases can be suppressed. If the firing temperature is 1400°C or lower, the decrease in specific surface area and the reduction of side reactions with the crucible can be reduced.

[0069] The firing atmosphere is not particularly limited and can be appropriately selected depending on the target metal oxide. For example, it may be in an air atmosphere or an inert gas atmosphere such as nitrogen. The firing pressure is typically between 0.01 and 1 MPa.

[0070] The solid-phase method may be either a high-pressure solid-phase synthesis method performed under high pressure or an atmospheric-pressure solid-phase synthesis method. As a known pressurizing device, for example, a DIA-type high-pressure generator, which is a multi-anvil device capable of generating high pressures up to about 10 GPa, can be used. In the case of the high-pressure solid-phase synthesis method, the pressure when heat-treating the mixture is 0.1 to 50 GPa, preferably 0.5 to 40 GPa, more preferably 1 to 20 GPa, for example, about 10 to 18 GPa.

[0071] [Platinum-carrying] The raw materials for the supported platinum are not particularly limited, and at least one can be used as a platinum precursor, selected from platinum salts such as chlorides, sulfides, hydrochlorides, sulfates, carbonates, and nitrates, and complexes such as dinitrodiammineplatinum complex and its nitrate solution. Examples of chlorides include chloroplatinic acid and hexachloroplatinic acid hexahydrate, and examples of nitrates include platinum nitrate and tetraammineplatin nitrate. As the nitrate solution of the dinitrodiammineplatinum complex, for example, a nitrate solution containing 0.5% dinitrodiammineplatinum complex can be used.

[0072] [Supported Rhodium] The raw material for the supported rhodium is not particularly limited, and at least one selected from rhodium salts such as chlorides, sulfides, hydrochlorides, sulfates, carbonates, and nitrates, and rhodium acetylacetonate can be used as the rhodium precursor. Examples of chlorides include rhodium chloride and rhodium chloride trihydrate, and examples of nitrates include rhodium nitrate hydrate.

[0073] [Platinum-supported method / Rhodium-supported method] The method for supporting platinum or rhodium on the above-mentioned carrier is not particularly limited. For example, an impregnation method can be used. For example, a platinum precursor or rhodium precursor equivalent to the amount to be charged is dissolved in a solvent, and the metal oxide that will serve as the carrier [A x B y O x+2y After adding [the specified substance] and stirring thoroughly, a Pt-supported catalyst or an Rh-supported catalyst can be prepared by drying and calcining. The solvent used in the impregnation method is not particularly limited as long as it can dissolve the platinum precursor or rhodium precursor, but water or acetone is preferred. Any drying conditions can be used as long as the solvent used can be removed. For example, vacuum evaporation or evaporation to dryness can be employed under reduced pressure in the range of room temperature to 80°C.

[0074] After drying, a Pt-supported catalyst or an Rh-supported catalyst can be prepared by final calcination. The firing temperature is preferably 300 to 990°C, more preferably 500 to 900°C. If the temperature is 300°C or higher, the remaining anions of the raw materials can be suppressed, and the interaction between platinum or rhodium and the support can be sufficient, resulting in excellent dispersibility of platinum or rhodium. If the temperature is 990°C or lower, problems such as a decrease in catalytic activity due to a decrease in the specific surface area of ​​the support, a decrease in interaction between the support materials, and the resulting platinum sintering or rhodium sintering can be avoided. As described above, for the Pt-supported catalyst or rhodium-supported catalyst of this embodiment, one method of controlling R represented by formula (2) is the firing temperature and atmosphere during the preparation of the Pt-supported catalyst or Rh-supported catalyst. By setting the firing temperature within the above range, it is possible to prepare a Pt-supported catalyst or Rh-supported catalyst that satisfies R represented by formula (2). The firing atmosphere is not particularly limited; for example, it may be in an air atmosphere or an inert gas atmosphere such as nitrogen. From the viewpoint of removing raw material anions, it is preferable to carry out the firing in an air atmosphere.

[0075] Because the Pt-supported catalyst or Rh-supported catalyst of this embodiment has high activity, it is possible to suppress hot spots by starting the exothermic reaction of hydrocarbon oxidation (combustion) at a low temperature, while maintaining synthesis gas production capacity at high temperatures. Furthermore, according to the present invention, since the catalyst is a catalyst in which the catalytic partial oxidation (CPOx) reaction is the target reaction, it is not necessary to supply heat from the outside during synthesis gas production, thus suppressing GHG emissions and reducing the environmental burden. [Examples]

[0076] The present invention will be described in detail below with reference to examples. However, the present invention is not limited in any way by the following examples. In the following examples, percentages are based on mass unless otherwise specified. The following items were evaluated.

[0077] (1) Measurement method of FT-IR (CO-DRIFTS) The FT-IR (CO-DRIFTS) spectra of the Pt-supported or Rh-supported catalysts prepared in each example were measured using a Bruker Optics "VERTEX 70v" instrument. The measurement conditions were a resolution of 4 cm. -1 , wavenumber range 600~7500cm -1 The detector was an MCT, and the number of integrations was set to 32 (data acquired at 1-minute intervals during continuous measurement). Measurements were taken using the diffuse reflectance method with a Specac "Selector" and an environmental chamber. As a pretreatment, the sample was heated to 150°C at a rate of 10°C / min under degassing conditions, held for 30 minutes, and then cooled to 35°C. The background spectrum was measured at 35°C under degassing conditions after pretreatment. Subsequently, CO was introduced into the sample and held for 30 minutes, then degassed again, and the IR spectrum was obtained after 30 minutes of degassing. The analysis was baseline-corrected using improved asymmetric reweighted penalized least squares (IarPLS) [Ye, J. et al., Applied Optics, 2020, 59, 10933-10943]. Baseline correction was applied from 1600 to 2300 cm. -1 The procedure is performed within the specified range, and the parameters of IARPLS are the smoothing parameter λ = 1 × 10 8 Difference degree = 2, maximum number of iterations = 50, convergence criterion = 1 × 10⁻¹⁰ -3 This was done. For the baseline-corrected absorbance (Abs) spectrum, 1700-1900 cm⁻¹ -1 , 1900~2200cm -1 For peaks with peak tops, we fitted them using the Voigt function. When multiple peaks were observed, we performed fitting with multiple Voigt functions. S1 is 1900-2100cm -1 The sum of the areas of the Voigt function with a peak top, S2, is 1800-1900 cm². -1 It was calculated as the sum of the areas of the Voigt function with peak tops at [location].

[0078] (2) Catalyst activity evaluation test 100 mg of the catalyst obtained in each example was packed into a quartz tube (6 mm inner diameter) and placed in the reactor. A thermocouple was inserted into the quartz tube to measure the internal temperature of the catalyst layer. The reactor was set to 288°C and heated under a nitrogen atmosphere. After heating, synthesis gas raw materials having the composition described later were supplied. After the raw material was supplied and the internal temperature of the catalyst layer stabilized, the outlet gas that had passed through the catalyst layer was analyzed using a gas chromatograph (Inficon Micro GC Fusion) with helium and argon as carrier gases, and Rt Molsieve 5A and Rt-Q-BOND (Restec) as columns, using a TCD detector to calculate the conversion rate and yield as shown in (2-1) and (2-2) below. The reaction temperature was increased from 288°C in 50°C increments while supplying the raw materials, up to 788°C. The pressure was set to atmospheric pressure (0.1 MPa).

[0079] [Raw materials for synthesis gas] CH4:5mL / min, O2:2.5mL / min, N2:12.5mL / min, total 20mL / min (2-1) Conversion rate of substance X to be measured (Flow rate at quartz tube inlet X - Flow rate at quartz tube outlet X) / (Flow rate at quartz tube inlet X) × 100 (2-2) Yield of substance X to be measured For CO: (CO flow rate at quartz tube outlet) / (CH4 flow rate at quartz tube inlet) × 100 For H2: (H2 flow rate at the quartz tube outlet) / (CH4 flow rate at the quartz tube inlet × 2) × 100

[0080] Example 1 (0.3wt%Pt / CaTiO3) To 180 mL of water, 400 mmol of citric acid and 20 mmol each of Ca(NO3)2·4H2O and [(CH3)2CHO]4Ti were added in a molar ratio of Ca:Ti=1:1, and the mixture was stirred at 100°C for 2 hours. Then, 25 mL of ethylene glycol was added, followed by calcination at 350°C for 3 hours. The resulting powder was then fully calcined at 1000°C for 2 hours to obtain the support CaTiO3 (A=Ca, B=Ti, x=1, y=1 in formula (1)). As a platinum precursor, a predetermined amount of Pt(NH3)2(NO2)2 was weighed and thoroughly dissolved in 5 mL of acetone. Then, a predetermined amount of CaTiO3 was added and the mixture was stirred for 3 hours to obtain a slurry. This slurry was evaporated to dryness while maintaining the temperature at 80°C to obtain a powder. The powder was calcined at 800°C for 2 hours to obtain 0.3 wt% Pt / CaTiO3. The results of the catalyst evaluation are shown in Table 1.

[0081] Example 2 (0.3wt%Pt / SrTiO3) SrCO3 and TiO2 were weighed in a molar ratio of 1:1 and physically mixed in an agate mortar for 30 minutes. The resulting physically mixed powder was calcined at 1000°C for 2 hours to obtain SrTiO3 (A=Sr, B=Ti, x=1, y=1 in equation (1)). As a platinum precursor, a predetermined amount of 0.5% Pt(NH3)2(NO2)2 nitric acid solution was weighed and thoroughly dissolved in water. A predetermined amount of SrTiO3 was then added, and the mixture was stirred for 3 hours to obtain a slurry. This slurry was evaporated under reduced pressure in an evaporator while maintaining the temperature at 50°C to obtain a powder. The powder was dried at 100°C for 2 hours, and then calcined at 800°C for 2 hours to obtain 0.3 wt% Pt / SrTiO3. The results of the catalyst evaluation are shown in Table 1.

[0082] Example 3 (0.3wt%Pt / BaTiO3) Except for using Ba(NO3)2 instead of Ca(NO3)2·4H2O, the same conditions as in Example 1 were used to prepare the support BaTiO3 (A=Ba, B=Ti, x=1, y=1 in formula (1)) and the platinum-supported catalyst (0.3wt%Pt / BaTiO3). The results of the catalyst evaluation are shown in Table 1.

[0083] Example 4 (0.3wt%Pt / ZrO2) Except for using ZrO2 instead of SrCO3, the same conditions as in Example 2 were used to prepare the ZrO2 support (B=Zr, x=0, y=1 in formula (1)) and the platinum-supported catalyst (0.3wt%Pt / ZrO2). The results of the catalyst evaluation are shown in Table 1.

[0084] Example 5 (0.3wt%Pt / CaZrO3) Except for using ZrO(NO3)2·2H2O instead of [(CH3)2CHO]4Ti to achieve a Ca:Zr=1:1 (molar ratio), the support CaZrO3 (A=Ca, B=Zr in formula (1), x=1, y=1) and the platinum-supported catalyst (0.3wt%Pt / CaZrO3) were prepared under the same conditions as in Example 1. The results of the catalyst evaluation are shown in Table 1.

[0085] Example 6 (0.3wt%Pt / SrZrO3) Except for using Sr(NO3)2 instead of Ca(NO3)2·4H2O and ZrO(NO3)2·2H2O instead of [(CH3)2CHO]4Ti, a support CaZrO3 (A=Sr, B=Zr, x=1, y=1 in formula (1)) and a platinum-supported catalyst (0.3wt%Pt / SrZrO3) were prepared under the same conditions as in Example 1, except that Sr(NO3)2 was used instead of Ca(NO3)2·4H2O and ZrO(NO3)2·2H2O was used instead of [(CH3)2CHO]4Ti, resulting in a Sr:Zr=1:1 (molar ratio). The catalyst evaluation results are shown in Table 1.

[0086] Example 7 (0.3wt%Pt / BaZrO3) Except for using Ba(NO3)2 instead of Ca(NO3)2·4H2O and ZrO(NO3)2·2H2O instead of [(CH3)2CHO]4Ti, a Ba:Zr=1:1 (molar ratio) was used to prepare a support BaZrO3 (A=Ba, B=Zr, x=1, y=1 in formula (1)) and a platinum-supported catalyst (0.3wt%Pt / BaZrO3). The results of the catalyst evaluation are shown in Table 1.

[0087] Comparative example 1 (0.3wt%Pt / TiO2) A TiO2 support and a platinum-supported catalyst (0.3 wt% Pt / TiO2) were prepared using the same conditions as in Example 2, except that TiO2 was used. The evaluation results of the catalysts are shown in Table 1.

[0088] Example 8 (0.3wt%Rh / CaTiO3) To 180 mL of water, 400 mmol of citric acid and 20 mmol each of Ca(NO3)2·4H2O and [(CH3)2CHO]4Ti were added in a molar ratio of Ca:Ti=1:1, and the mixture was stirred at 100°C for 2 hours. Then, 25 mL of ethylene glycol was added, followed by calcination at 350°C for 3 hours. The resulting powder was then fully calcined at 1000°C for 2 hours to obtain the support CaTiO3 (A=Ca, B=Ti, x=1, y=1 in formula (1)). As a rhodium precursor, [CH3COCH=C(O - A predetermined amount of [CH3]3Rh was weighed and thoroughly dissolved in 5 mL of acetone. A predetermined amount of CaTiO3 was then added, and the mixture was stirred for 3 hours to obtain a slurry. This slurry was evaporated to dryness while maintaining the temperature at 80°C to obtain a powder. The powder was calcined at 800°C for 2 hours to obtain 0.3 wt% Rh / CaTiO3. The catalyst evaluation results are shown in Table 2.

[0089] Example 9 (0.3wt%Rh / SrTiO3) Except for using Sr(NO3)2 instead of Ca(NO3)2·4H2O, the same conditions as in Example 8 were used to prepare the support SrTiO3 (A=Sr, B=Ti, x=1, y=1 in formula (1)) and the rhodium-supported catalyst (0.3wt%Rh / SrTiO3). The results of the catalyst evaluation are shown in Table 2.

[0090] Example 10 (0.3wt%Rh / BaTiO3) Except for using Ba(NO3)2 instead of Ca(NO3)2·4H2O, the same conditions as in Example 8 were used to prepare the support BaTiO3 (A=Ba, B=Ti, x=1, y=1 in formula (1)) and the rhodium-supported catalyst (0.3wt%Rh / BaTiO3). The results of the catalyst evaluation are shown in Table 2.

[0091] Example 11 (0.3 wt% Rh / ZrO2) ZrO2 was pre-calcined at 1000°C for 2 hours to obtain the ZrO2 support (B=Zr, x=0, y=1 in formula (1)). As a rhodium precursor, [CH3COCH=C(O -A predetermined amount of [CH3]3Rh was weighed and thoroughly dissolved in 20 mL of acetone. A predetermined amount of ZrO2 was then added, and the mixture was stirred for 3 hours to obtain a slurry. This slurry was evaporated under reduced pressure in an evaporator while maintaining the temperature at 25°C to obtain a powder. The powder was calcined at 800°C for 2 hours to prepare a rhodium-supported catalyst (0.3 wt% Rh / ZrO2). The results of the catalyst evaluation are shown in Table 2.

[0092] Example 12 (0.3wt%Rh / CaZrO3) CaCO3 and ZrO2 were weighed in a molar ratio of 1:1 and physically mixed in an agate mortar for 30 minutes. The resulting physically mixed powder was calcined at 1000°C for 2 hours to obtain the support CaZrO3 (A=Ca, B=Zr, x=1, y=1 in formula (1)). Rh was supported in the same manner as in Example 11 to prepare a rhodium-supported catalyst (0.3 wt% Rh / CaZrO3). The evaluation results of the catalyst are shown in Table 2.

[0093] Example 13 (0.3wt%Rh / SrZrO3) A support SrZrO3 (A=Sr, B=Zr, x=1, y=1 in formula (1)) and a rhodium-supported catalyst (0.3wt%Rh / SrZrO3) were prepared under the same conditions as in Example 12, except that SrCO3 was used instead of CaCO3. The results of the catalyst evaluation are shown in Table 2.

[0094] Example 14 (0.3wt%Rh / BaZrO3) A support BaZrO3 (A=Ba, B=Zr, x=1, y=1 in formula (1)) and a rhodium-supported catalyst (0.3wt%Rh / BaZrO3) were prepared under the same conditions as in Example 12, except that BaCO3 was used instead of CaCO3. The results of the catalyst evaluation are shown in Table 2.

[0095] [Table 1]

[0096] [Table 2]

Claims

1. A catalyst for producing synthesis gas containing carbon monoxide and hydrogen from hydrocarbons, wherein the catalyst is represented by the following formula (1) and satisfies the following formula (2). M / A ｘ B ｙ O ｘ＋２ｙ (1) [In equation (1), M is either Pt or Rh. A is at least one element selected from divalent metallic elements, B is at least one element selected from tetravalent metallic elements. O is oxygen, A real number satisfying 0 ≤ x ≤ 1, It is a real number satisfying the condition 0 < y ≤ 1. R=S2 / (S1+S2)≦0.1 (2) [In equation (2), S1: Peak area derived from Linear-CO adsorbed on Pt particles or Rh particles in CO-DRIFTS measurement. S2: Peak area derived from Bridge-CO adsorbed on Pt particles or Rh particles in CO-DRIFTS measurement.

2. The catalyst according to claim 1, wherein in formula (1), A is at least one element selected from the group consisting of Ca, Sr, and Ba.

3. The catalyst according to claim 1, wherein in formula (1), B is at least one element selected from the group consisting of Zr and Ti.

4. The catalyst according to claim 1, wherein in formula (1), when x = 0, B is Zr.

5. The catalyst according to claim 1, wherein the amount of Pt or Rh supported in formula (1) is less than 1% by mass.

6. The catalyst according to claim 1, wherein M in formula (1) is Pt, and R ≤ 0.09 in formula (2).

7. The catalyst according to claim 1, wherein M in formula (1) is Rh, and in formula (2), 0 ≤ R ≤ 0.

1.

8. A synthesis gas production apparatus comprising: a reactor through which a gas to be treated containing at least hydrocarbons flows; and a catalyst disposed inside the reactor at a position in contact with the gas to be treated, wherein the catalyst is the catalyst described in claim 1.

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