Ammonia-hydrogen mixed fuel production apparatus, fuel supply system, and hydrogen production method

Abstract

[Problem] To provide: an ammonia-hydrogen mixed fuel production apparatus capable of stably obtaining hydrogen from ammonia even when there is a change in the required ratio of fuel; and a fuel supply system. [Solution] An ammonia-hydrogen mixed fuel production apparatus 1010A comprises: an oxygen separation device 13 that separates oxygen (O2) 12 at a desired concentration from air 11; a reforming reactor 15 that converts ammonia (NH3) supplied from a raw material supply unit 14 into hydrogen (H2) by using the oxygen having the desired concentration from the oxygen separation device 13; and a gas component analyzer 17 that measures the concentration of one or both of hydrogen and ammonia in a reformed gas 16 from the reforming reactor 15.

Description

Ammonia-hydrogen blended fuel production device, fuel supply system, and hydrogen production method

[0001] The present invention relates to an apparatus for producing ammonia-hydrogen mixed fuel, a fuel supply system, and a method for producing hydrogen.

[0002] Recently, ammonia utilization technology has been attracting attention as a way to achieve carbon neutrality. ３ ) to hydrogen (H ２ One example of a method for producing ethylenediaminetetraacetic acid is the ammonia decomposition method (see Patent Document 1).

[0003] JP 2022-144912 A JP 2023-83706 A

[0004] However, the proposed decomposition method for obtaining hydrogen from ammonia disclosed in Patent Document 1 requires the use of an ammonia decomposition device that supplies heat from outside the reactor. This ammonia decomposition device using external heating uses, for example, a burner to decompose ammonia (NH ３ ) and H2, which is the off-gas from the PSA (Pressure Swing Adsorption) unit. ２ / N ２ This method involves mixing ammonia gas with air (oxygen) and burning it, but the main fuel, ammonia, burns slower than other fuels such as methane, and there are challenges not only in ensuring reliable ignition and stabilizing combustion, but also in suppressing the production of nitrogen oxides.

[0005] Incidentally, the fuel composition (hydrogen / ammonia composition ratio) and flow rate may vary depending on the requirements of downstream boilers, gas engines, industrial furnaces, etc. When the turndown is large (for example, the turndown ratio fluctuates from 100% to 20%, or the hydrogen ratio fluctuates from 100% to 20%), it becomes difficult to stably burn ammonia by external heating or to quickly respond to fluctuations when converting ammonia to hydrogen in an ammonia cracker.

[0006] In an ATR (Autothermal Reformer) device that oxidatively decomposes ammonia, ammonia is oxidized by oxygen in an oxidative decomposition catalyst section. Self-heating due to oxidation causes oxidative decomposition and decomposition reactions of ammonia in the ATR catalyst section, resulting in reforming into hydrogen. In the prior art technology described in Patent Document 2, ammonia, the raw material for ammonia reforming, itself oxidizes on the catalyst. Therefore, oxidation does not occur unless the catalyst is heated to 200°C or higher, so the catalyst or raw material gas must be preheated in advance.

[0007] In addition, the target of the present invention is 100 m per hour. ３ ~2,000m ３ Small- to medium-sized systems capable of generating hydrogen of this magnitude produce fuel for heating furnaces, gas engines, and boilers, which have large load fluctuations and require frequent daily start and stop (DSS), so they need to respond quickly to load fluctuations and DSS. Furthermore, because they are small- to medium-sized, the reactor size is small, and if a lot of heat is released from the reactor, the amount of ammonia oxidation must be increased to compensate for the heat required for the ammonia decomposition reaction, resulting in lower hydrogen yield and thermal efficiency. Furthermore, in order to package the system, the number of devices must be reduced and the reactor must be compact.

[0008] Furthermore, when hydrogen is supplied to boilers, industrial furnaces, etc., these are subject to frequent turndown, shutdown, and startup, so a self-sustaining system that can respond easily and quickly is desirable. In the case of conventional technology, these devices require heating to 200°C or higher at startup, at which point the oxidative decomposition reaction can begin, which necessitates the installation of separate heating equipment, making the equipment more complex and making it difficult to respond quickly.

[0009] In view of the above problems, the present invention provides an ammonia-hydrogen mixed fuel production device, a fuel supply system, and a hydrogen production method that can stably and quickly obtain hydrogen from ammonia even when the required composition ratio or amount of fuel changes.

[0010] (1) An ammonia-hydrogen mixed fuel manufacturing apparatus according to one aspect of the present invention comprises: an oxygen supply unit that supplies oxygen at a desired concentration; a reforming reactor that converts ammonia to hydrogen using the oxygen at the desired concentration from the oxygen supply unit to produce a reformed gas; and a gas component analyzer that measures the concentration of either hydrogen or ammonia, or both, in the reformed gas from the reforming reactor.

[0011] (2) In another aspect of the ammonia-hydrogen mixed fuel production apparatus according to the present invention, the oxygen supply unit is an oxygen separation device that separates oxygen from air to a desired concentration.

[0012] (3) In another aspect of the present invention, there is provided an apparatus for producing ammonia and hydrogen mixed fuel, wherein the oxygen supply unit is an air dryer that removes moisture from the supplied air.

[0013] (4) In another aspect of the present invention, the apparatus for producing ammonia-hydrogen mixed fuel is characterized in that the oxygen supply unit adds 3 to 20% by volume of oxygen to the amount of ammonia supplied.

[0014] (5) Another aspect of the ammonia-hydrogen mixed fuel manufacturing apparatus according to the present invention is characterized in that the amount of oxygen supplied from the oxygen supply unit is controlled based on the concentration of either or both of the hydrogen and the ammonia from the gas component analyzer.

[0015] (6) Another aspect of the ammonia-hydrogen mixed fuel manufacturing apparatus according to the present invention is characterized in that a bypass line for supplying the ammonia from the raw material supply unit is provided between the reforming reactor and a measurement point of the gas component analyzer downstream of the reforming reactor.

[0016] (7) Another aspect of the ammonia-hydrogen mixed fuel manufacturing apparatus according to the present invention comprises: a bypass line for supplying ammonia from a raw material supply unit between the reforming reactor and a measurement point of the gas component analyzer downstream of the reforming reactor; and a storage tank provided between the ammonia introduction position of the bypass line and the reforming reactor; and the apparatus adjusts the gas composition of the reformed gas and ammonia according to the composition ratio of ammonia and hydrogen measured by the gas component analyzer and a required fuel composition ratio.

[0017] (8) Another aspect of the ammonia-hydrogen mixed fuel production device according to the present invention is characterized in that the reforming reactor comprises: a housing having an inlet for introducing ammonia and a flammable gas other than ammonia and an outlet for discharging a generated gas; a first catalyst unit disposed inside the housing and having a first catalyst that generates heat by burning the flammable gas introduced from the inlet; and a second catalyst unit disposed between the first catalyst unit and the outlet, heated by the heat generated in the first catalyst unit, and having a second catalyst that generates hydrogen from ammonia.

[0018] (9) In another aspect of the present invention, there is provided an apparatus for producing ammonia and hydrogen mixed fuel, wherein the first catalyst section is disposed between the inlet and the second catalyst section.

[0019] (10) In another aspect of the present invention, there is provided an ammonia-hydrogen mixed fuel production apparatus, wherein the reactor includes a dispersion section between the first catalyst section and the second catalyst section, which disperses the gas flowing out from the first catalyst section toward the second catalyst section.

[0020] (11) Another aspect of the present invention is an ammonia-hydrogen mixed fuel manufacturing apparatus comprising: an outlet flow path for discharging hydrogen from the outlet; a tank provided in the outlet flow path for storing the discharged hydrogen; and a return flow path branched from a branching portion of the outlet flow path for returning the hydrogen to the inlet.

[0021] (12) A fuel supply system according to another aspect of the present invention is characterized in that it uses the ammonia-hydrogen mixed fuel production device according to (1) or (2) and supplies ammonia reformed fuel to a fuel demand section.

[0022] (13) Another aspect of the method for producing hydrogen according to the present invention includes: an introduction step of introducing an introduction gas containing ammonia and a combustible gas other than ammonia into a reactor; a combustion step of selectively combusting the combustible gas in the introduced introduction gas with a first catalyst; a second catalyst heating step of heating a second catalyst that generates hydrogen from ammonia with heat generated in the combustion step; and a reforming step of stopping the introduction of the combustible gas after the temperature of the second catalyst reaches a predetermined temperature and generating hydrogen from ammonia using the second catalyst.

[0023] According to the present invention, hydrogen can be stably obtained from ammonia even when the required fuel ratio changes. The present disclosure provides a reactor and a hydrogen production method with high thermal efficiency that can quickly respond to load fluctuations and start-up / shutdown on the demand side.

[0024] 1 is a schematic diagram of an apparatus for producing ammonia and hydrogen mixed fuel according to a first embodiment of the present invention. FIG. 1 is a schematic diagram of an apparatus for producing ammonia and hydrogen mixed fuel according to a second embodiment of the present invention. FIG. 2 is a schematic diagram of an apparatus for producing ammonia and hydrogen mixed fuel according to a third embodiment of the present invention. FIG. 3 is a schematic diagram of an apparatus for producing ammonia and hydrogen mixed fuel according to a fourth embodiment of the present invention. FIG. 4 is a cross-sectional view showing the internal structure of a reactor according to a fifth embodiment. FIG. 5 is a structural diagram of a distribution section to be installed inside the reactor according to the fifth embodiment. FIG. 6 is a structural diagram of another distribution section to be installed inside the reactor according to the fifth embodiment. FIG. 7 is a cross-sectional view showing the internal structure of another reactor according to the fifth embodiment. FIG. 8 is a perspective view of a first catalyst section, illustrating the size of the first catalyst section. FIG. 9 is a perspective view of a second catalyst section, illustrating the size of the second catalyst section. FIG. 10 is a diagram illustrating a temperature gradient between the second catalyst section and a housing. FIG. 11 is a diagram illustrating a structure for starting a reactor using at least a part of hydrogen produced in the second catalyst section. FIG. 12 is a graph showing the temperature distribution inside a reactor when a combustible gas is combusted in a catalyst section under specific reaction conditions in the fifth embodiment. FIG. 13 is a graph showing the temperature distribution inside a reactor when ammonia reforming is performed in the reactor without adding a combustible gas. FIG. 14 is a flowchart showing a method for producing hydrogen. 14 is a cross-sectional view showing the internal structure of a reactor according to a sixth embodiment. FIG. 15 is a cross-sectional view showing the internal structure of a reactor according to a seventh embodiment. FIG. 16 is a cross-sectional view taken along line A-A in FIG. 14, and is a cross-sectional view of a second catalyst section installed in the second stage.

[0025] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the embodiments of this specification, the same components are designated by the same reference numerals throughout.

[0026] [First embodiment] Fig. 1 is a schematic diagram of an ammonia-hydrogen mixed fuel production apparatus according to a first embodiment of the present invention. As shown in Fig. 1, an ammonia-hydrogen mixed fuel production apparatus 1010A of this embodiment converts air 1011 into oxygen (O ２ ) to a desired concentration, and ammonia (NH ３ ) to hydrogen (H ２and a gas component analyzer 1017 that measures the concentration of either hydrogen or ammonia, or both, in reformed gas 1016 from the reforming reactor 1015.

[0027] The raw material supply unit 1014 supplies ammonia (NH ３ ) is supplied from the raw material supply unit 1014 to the reforming reactor 1015 via an ammonia supply line L1. ３ The reformed gas 1016 from the reforming reactor 1015 is passed through a reformed gas discharge line L2 and is used as fuel 1018 on the external demand side X.

[0028] An oxygen separation device 1013 is also provided to obtain oxygen from air 1011, and the separated oxygen is supplied to an ammonia supply line L1 via an oxygen supply line L3. Examples of this oxygen separation device 1013 include a cryogenic separation device, a pressure swing adsorption (PSA) device, and a membrane separation device, but the present invention is not limited to these. In the following description, a pressure swing adsorption (hereinafter also referred to as "PSA") device will be described as an example, but the present invention is not limited thereto.

[0029] The reformed gas discharge line L2 is supplied with fuel 1018, which is a mixture of ammonia (NH3) and hydrogen (H ２ ) and the composition ratio (NH ３ / H ２ A gas component analyzer 1017 is provided to measure the gas composition.

[0030] The gas component analyzer 1017 may be, for example, a hydrogen detector for detecting hydrogen, an ammonia detector for detecting ammonia, or an ammonia-hydrogen composition ratio detector for detecting the composition ratio of hydrogen to ammonia, but the present invention is not limited to these. Here, the main analyzer used as the gas component analyzer 1017 is, for example, a gas chromatograph (H ２ , N.H. ３ Gas), thermal conductivity gas analyzer (H ２ gas), infrared absorption spectrophotometer (NH３ However, the present invention is not limited to such a gas.

[0031] In this way, the composition ratio (NH3 / H2) in the reformed gas 1016 obtained by reforming the raw material ammonia in the reforming reactor 1015 is measured by the gas component analyzer 17, thereby constantly or intermittently measuring the fuel composition required by the downstream demand section X. This measurement may be sent online to a separate control device and automatically controlled. As an example, a control device (not shown) may be configured to correct the difference between the fuel composition required by the demand section X and the measured fuel composition.

[0032] In this embodiment, ammonia (NH ３ ) with respect to the supply amount of oxygen (O ２ It is preferable to add 3% by volume or less of H O ... ２ This is because it leads to a decrease in yield and thermal efficiency, which is undesirable.

[0033] Here, to produce hydrogen from ammonia, as shown in the following formula (1), in the case of external heating, this endothermic heat is converted into NH ３ / N ２ is burned and fed to the reaction tube. ３ →0.5N ２ +1.5H ２ Endotherm ΔH=+45.9 kJ / mol (1) However, as the NH3 decomposition reaction progresses, the reaction temperature drops, and the reaction will eventually stop unless heat is supplied.

[0034] In the present invention, when 12 to 16% by volume of oxygen is added, the heat generated by the two oxidation reactions of the following formulas (2) and (3) can cover the endothermic heat of the ammonia decomposition reaction, thereby achieving a high decomposition rate. ３ +0.25O ２ →H ２ +0.5N ２ +0.5H ２O Heat generation △H = -75 kJ / mol ... (2) H ２ +0.5O ２ →H ２ O Heat generation △H = -284 kJ / mol ... (3)

[0035] As described above, the conversion rate increases as the reaction temperature (the amount of oxygen added) and the amount of catalyst increase. However, if the amount of oxygen added is too large, ammonia and the generated hydrogen are oxidized (consumed) by oxygen, so there is an upper limit to the conversion rate of ammonia (NH ３ On the other hand, if the amount is too small, the increase in reaction temperature due to heat generation is small, and the reaction (decomposition rate) does not proceed below the temperature required for the ammonia decomposition reaction, so there is a lower limit, and the amount is set to, for example, 3% by volume relative to the amount of ammonia (NH3) supplied.

[0036] As the reforming catalyst for the reforming reactor 1015, it is preferable to use a known NH3-ATR catalyst and a known NH3 decomposition catalyst, either singly or in combination. When these are used in combination, the "NH3-ATR catalyst" and the "NH ３ The ratio of the catalyst to the decomposition catalyst is preferably 1:0 to 1:10, more preferably 1:2 to 1:6.

[0037] In the above-mentioned ammonia decomposition (1) and ammonia oxidation (2) + (3) combined with the optimal catalyst, the oxidation reaction proceeds 100% in 20-30% of the entire catalyst layer because of its fast reaction rate, whereas the decomposition reaction is slower than the oxidation reaction and requires a large amount of catalyst because the reaction temperature drops as the reaction progresses.

[0038] Therefore, it is preferable to divide the optimal catalyst for each reaction in the amount required for the above reactions in a ratio of 1:2 to 1:6. Also, some catalysts are suitable for both reactions, and in such cases, one type of catalyst (1:0) may be used.

[0039] The ATR catalyst is preferably a catalyst made of one or more of ruthenium (Ru), platinum (Pt), nickel (Ni), cobalt (Co), iron (Fe), manganese (Mn), and molybdenum (Mo), but the present invention is not limited to this.

[0040] The NH3 decomposition catalyst is preferably a catalyst made of one or more of ruthenium (Ru), nickel (Ni), cobalt (Co), iron (Fe), manganese (Mn), and molybdenum (Mo), but the present invention is not limited to this.

[0041] The reaction temperature in the reforming reactor 1015 is, for example, 150 to 850°C, preferably 300 to 700°C, and the pressure is 0.03 to 0.9 MPa, preferably 0.07 to 0.7 MPa. The reason for specifying the temperature and pressure within the predetermined ranges is to allow the reforming reaction to proceed efficiently.

[0042] The reaction depends on the performance of the catalyst, but for example, it starts at 150 to 200°C, and the reaction rate increases with the reaction temperature. For example, if the temperature is above 650 to 700°C, the activity of the catalyst may decrease (for example, if the heat promotes aggregation of the active metal, reducing the active surface area). Therefore, the reaction temperature is preferably in the range of 150 to 850°C.

[0043] Furthermore, high temperatures cause nitriding of the reaction tube material, which is undesirable for both the catalyst and the reaction tube. Lower pressures are more favorable for hydrogen production in terms of chemical equilibrium, but considering the supply pressure to downstream combustion equipment and pressure losses due to catalyst layers, etc., a pressure of 0.03 to 0.9 MPa is preferable. Note that when a honeycomb catalyst (which has low pressure loss) is used as the catalyst, or depending on the downstream equipment, a low pressure such as 0.07 MPa may be more favorable for the reaction.

[0044] This ammonia-hydrogen mixed fuel production device is used to supply the ammonia (NH ３ ) to create a fuel supply system.

[0045] Here, the gas component analyzer 17 can measure either or both of the hydrogen concentration and the ammonia concentration, but in this embodiment, hydrogen measurement will be described as an example.

[0046] That is, in response to a request (NH3 / H2 composition, flow rate) for fuel 1018 from a demand unit X such as an engine, boiler, or heating furnace arranged downstream, a gas component analyzer (hydrogen detector) 1017 installed downstream of the reforming reactor 15 detects the hydrogen (H2) concentration in the reformed gas 1016 and calculates the requested H ２ The amount of oxygen supplied from the oxygen separator 1013 is controlled so as to satisfy the concentration (NH3 decomposition rate).

[0047] The decomposition rate of ammonia (NH3) is ３ ) increases with the amount of oxygen (O2) added. ３ ) 0 to 16 vol% oxygen (O ２ ) can be added to control the range of 0 to 100 vol%. ３ →0.5N ２ +1.5H ２ ... (4) <Endothermic reaction> 2NH ３ +O ２ →N ２ +H ２ +2H ２ O → NH ３ +0.25O2 →H ２ +0.5N ２ +0.5H ２ O...(5) <Exothermic reaction> H ２ +0.5O ２ →H ２ O... (6) <Exothermic reaction>

[0048] NH in the above-mentioned formulas (5) and (6) ３ ,H ２ The heat generated by the oxidation reaction is used to react with NH ３ This promotes the decomposition reaction. As a result, ammonia is used as a raw material. The product ammonia (NH3) / hydrogen (H ２ ) mixed gas supply amount and its hydrogen (H ２ ) concentration can be freely controlled.

[0049] As described above, according to the present invention, ammonia (NH ３ ) to hydrogen (H ２ ) to produce hydrogen (H ２) production, for example, to supply fuel to engines, boilers, heating furnaces, etc., and depending on the purpose and demand, ammonia (NH ３ ) / Hydrogen (H ２ ) composition ratio (composition ratio combustable by, for example, a combustion appliance on the fuel demand section X side) can be adjusted according to demand.

[0050] Test Example A test example according to the first embodiment will be described below, but the present invention is not limited thereto. Ammonia (NH ３ ) and oxygen (O ２ ) and H ２ / NH ３ The mixed gas fuel was produced under the following conditions. Here, an air separation PSA was used as the oxygen separator 13, and air 11 was supplied and separated to a concentration of 90% (O ２ ) was used.

[0051] The test conditions were as follows: Pressure: 0.1 MPa Inlet temperature: 230°C NH3 flow rate: 280 Nm 3 / hr O2 flow rate: 42Nm ３ / hr (N2 containing flow rate: 4.6Nm ３ / hr)

[0052] Hydrogen (H2) concentration 95 vol% (H ２ and N.H. ３ (mixture gas base) against the demand for ammonia (NH ３ ) to oxygen (O ２ The composition of the mixed gas obtained under the above operating conditions with 15 vol% of H added is as follows: ２ / NH ３ / N ２ = 67.8 / 3 / 29.2 vol ratio This is H ２ / NH ３ Hydrogen (H ２ ) concentration is 95.8%.

[0053] On the other hand, hydrogen (H ２ When the required hydrogen (H) concentration is changed from 95% to 50%,２ ) concentration is measured by the gas component analyzer 1017 ２ While detecting with a detector, oxygen (O ２ As a result of controlling the supply of oxygen (O ２ ) is ammonia (NH ３ A gas that met the requirements was obtained at 10 vol% of H. ２ / NH ３ / N ２ = 42 / 19.9 / 38.1 vol ratio This is H ２ / NH ３ Hydrogen (H ２ ) concentration is 52.3%.

[0054] [Second embodiment] Fig. 2 is a schematic diagram of an ammonia-hydrogen mixed fuel production apparatus. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted. As shown in Fig. 2, an ammonia-hydrogen mixed fuel production apparatus 1010B of this embodiment has a reformed gas discharge line L for discharging reformed gas 1016 from a reforming reactor 1015. ２ The raw material ammonia (NH ３ ) is directly supplied from the raw material supply unit 14 through a bypass line L4. ４ The ammonia introduction position B is located between the reforming reactor 15 and the measurement point A of the gas component analyzer 17 downstream of the reforming reactor 15. １１ is the first signal line, V １ is the first on-off valve.

[0055] In this way, the bypass line L ４ By installing the hydrogen (H ２ ) concentration is low, or hydrogen (H ２ When it is necessary to quickly respond to a request to reduce the concentration from a high concentration (for example, 100 Vol%) to a low concentration (for example, 30 Vol%), the gas component analyzer 17 controls the first on-off valve V １ The first signal S １ and the first shut-off valve V １ is opened, and ammonia (NH ３) to bypass line L ４ This allows the reforming reactor 15 to be bypassed and the ammonia to be directly supplied to the hydrogen detector, which is the gas component analyzer 17, so that the ammonia concentration can be quickly adjusted to the required low concentration (for example, 30 Vol%).

[0056] [Third embodiment] Fig. 3 is a schematic diagram of an apparatus for producing ammonia-hydrogen mixed fuel. Note that the same components as those in the first and second embodiments are denoted by the same reference numerals, and the description thereof will be omitted. As shown in Fig. 3, an apparatus for producing ammonia-hydrogen mixed fuel 1010C of this embodiment has a reformed gas discharge line L for discharging reformed gas 1016 from a reforming reactor 1015. ２ A reservoir tank 1021 for temporarily storing the reformed gas 1016 is provided in the １２ is the second signal line, V ２ is a second on-off valve. The reservoir 1021 is designed to store the reformed gas 16 at a constant concentration.

[0057] In this embodiment, by providing the bypass line L4 and the storage tank 1021, when the required hydrogen (H2) concentration in the fuel 1018 gas is low or when it is necessary to quickly respond to a request to reduce the hydrogen (H2) concentration from a high concentration (for example, 100 Vol%) to a low concentration (for example, 30 Vol%), the gas component analyzer 1017 sends a first signal S1 to the first on-off valve V1, and ammonia from the raw material supply unit 1014 that adjusts the first on-off valve V1 bypasses the reforming reactor 15 via the bypass line L4, and the ammonia is supplied directly before the gas component analyzer 1017, making it possible to quickly adjust the composition of the adjusted gas 16A to the required concentration (low concentration (for example, 30 Vol%)).

[0058] At this time, the gas component analyzer 1017 may send a second signal S2 to the second on-off valve V2 to adjust the second on-off valve V2, thereby adjusting the supply ratio of the modified gas 1016 to produce the adjusted gas 16A.

[0059] This makes it possible to adjust the gas composition of the reformed gas and ammonia (for example, from 30 / 70 to, for example, 20 / 80) according to the composition of ammonia and hydrogen (for example, 30 / 70) measured by the gas component analyzer 1017.

[0060] [Fourth Embodiment] FIG. 4 is a schematic diagram of an ammonia-hydrogen mixed fuel production apparatus. Note that the same components as those in the first to third embodiments are denoted by the same reference numerals, and their description will be omitted. In the first to third embodiments, the oxygen separation device 13A was used. However, the oxygen supply unit for supplying oxygen in the present invention is not limited to this. For example, an air dryer 1013B may be used to remove moisture from the supplied air. As shown in FIG. 4, the ammonia-hydrogen mixed fuel production apparatus 10D of this embodiment is equipped with an air dryer 1013B that removes moisture from the air 1011 supplied by, for example, an air compressor. The oxygen supply unit of this embodiment is composed of an air compressor (not shown) that supplies air and the air dryer 1013B installed downstream. Here, the air dryer 1013B can be either an adsorption type or a cooling type.

[0061] This air dryer 1013B removes moisture from the air and prevents water from poisoning a catalyst such as platinum (Pt) used in the reforming reactor 1015. The adsorption method is a method of removing moisture using, for example, zeolite.

[0062] The cooling method can remove moisture by adjusting the saturated vapor pressure corresponding to the cooling temperature (for example, by cooling to 20°C or less). The cooling temperature is preferably 20°C or less, and more preferably -20°C or less.

[0063] According to this embodiment, when oxygen is supplied from air, moisture in the air is removed, thereby preventing, for example, a platinum (Pt) catalyst used in the reforming reactor 1015 from being poisoned.

[0064] [Fifth Embodiment] Next, specific variations of the reforming reactors of the first to fourth embodiments will be described. Fig. 5 is a cross-sectional view showing the internal structure of a reactor 10 of the fifth embodiment. The reactor 10A is a reactor that performs autothermal reforming (ATR) of ammonia. The reactor 10 includes a first catalyst section 13 and a second catalyst section 21.

[0065] In the reactor 10A, heat is generated by combustion of a combustible gas such as hydrogen in the first catalytic section 13. The gas G2 having the generated heat flows into the second catalytic section 21, thereby heating the second catalytic section 21. In the second catalytic section 21, the reaction heat of the ammonia decomposition reaction (endothermic reaction) is supplied by utilizing the heat generated by the partial oxidation reaction (exothermic reaction) of ammonia using oxygen. Therefore, the reactor 10A is thermally self-sustaining without the need for an external heat source (such as a heating furnace), and can decompose ammonia (produce hydrogen) with an efficient and simple reactor configuration.

[0066] The reactor 10A has a configuration that can generate a reaction for heating the second catalyst section 21 used for ammonia reforming before the ammonia reforming. This reaction proceeds inside the reactor 10A, and there is no need to provide a heat source outside the reactor 10A that supplies heat to the inside of the reactor 10A. With this configuration, the reactor 10A can be quickly started up when ammonia reforming is performed, and the time required for starting reforming and changing the load can be shortened.

[0067] The reactor 10A includes a housing 1, which includes an inlet 2 and an outlet 3. The housing 1 has a cylindrical shape that is circular when viewed from above, but may also have a rectangular, angular shape when viewed from above. The cross-sectional areas of the inlet 2 and a flow path 11 formed therein are different, and the inlet 2 and the outlet 3 are narrower than the internal flow path 11 (a portion with a locally expanded cross-sectional area). The flow path 11 is formed between the inlet 2 and the outlet 3. Gas G (gases G1, G2, and G3) flows through the flow path 11, as will be described in detail later.

[0068] The flow path 11 is defined by a heat insulating material 12 arranged along the inner wall of the housing 1. The housing 1 is not completely cylindrical, but has a shape that locally narrows inside near the inlet 2. Furthermore, near the outlet 3, the housing 1 has a shape that narrows toward the outlet 3. Of the flow path 11 formed by being surrounded by the heat insulating material 12, the shape between the inlet 2 and the upper end of the locally widened portion formed below the inlet 2 has a cylindrical shape (circular in top view). However, the shape between the inlet 2 and the upper end of the locally widened portion formed below the inlet 2 may have a square tube shape (rectangular in top view).

[0069] The inlet 2 is an opening for introducing the gas G1 into the inside of the housing 1 (reactor 10A). The gas G1 is a gas containing ammonia and flammable gases other than ammonia. Therefore, ammonia and flammable gases other than ammonia are introduced into the inside of the housing 1 through the inlet 2. Hereinafter, the term "flammable gas" refers to flammable gases excluding ammonia. The definition and examples of flammable gases will be described later.

[0070] It is not necessary for ammonia and the flammable gas to be supplied simultaneously in a mixed state. Therefore, for example, ammonia and the flammable gas are introduced into the reactor 10 through the inlet 2, either together or independently. The flammable gas may be, for example, hydrogen. The gas G1 may also contain components used in the combustion of the flammable gas and the ammonia reforming, such as oxygen. The gas G1 may also contain gases other than ammonia, the flammable gas, and oxygen. The gas G1 introduced into the housing 1 is supplied to the first catalyst unit 13. The gas G1 introduced into the first catalyst unit 13 generates the gas G2 by a catalytic reaction.

[0071] Gas G2 flows out from the first catalytic section 13 and flows into the second catalytic section 21. Gas G2 contains ammonia heated by heat generated by the combustion of the combustible gas in gas G1 and oxygen not used in the first catalytic section 13. Gas G2 may also contain unburned combustible gas.

[0072] Gas G3 generated by the catalytic reaction flows out from the second catalyst section 21 and flows out from the outlet 3. The outlet 3 is an opening that allows the gas G3 to flow out from the inside of the housing 1 (reactor 10). The gas G3 is, for example, hydrogen generated in the reactor 10, nitrogen generated in association with the hydrogen, unreacted gas or associated gas of the introduced gas G1, etc. Hereinafter, the gases G1, G2, and G3 will be collectively referred to as gas G.

[0073] The reactor 10 can be operated at a rate of, for example, 100 m per hour. ３ ~2,000m ３The reactor 10 has a small to medium size capable of generating hydrogen of 1000 kJ / s. The gas hourly space velocity (GHSV) of the gas G that can flow through the inside of the reactor 10 is, for example, 3,000 / hr or more and 50,000 / hr or less, preferably 5,000 / hr or more and 30,000 / hr or less. Therefore, as for the size of the reactor 10, for example, if the housing 1 has a cylindrical (approximately cylindrical) shape, the diameter of the housing 1 can be set to 300 mm or more and 800 mm or less. Furthermore, if the housing 1 is a square housing having a rectangular shape when viewed from above, the width and depth of the housing 1 can both be set to 300 mm or more and 800 mm or less.

[0074] As in the present disclosure, if the diameter, width, and depth are less than 1 m, for example, the outer surface area of ​​the casing 1 per unit volume of the first catalytic section 13 and the second catalytic section 21 becomes large, making heat radiation to the outside of the wall surface of the reactor 10A more likely. Furthermore, if the diameter, width, and depth of the casing 1 are increased to suppress heat radiation, the height of the casing 1 becomes smaller. This reduces the flow rate of the gas G, which may result in the gas G not dispersing uniformly inside the casing 1 or making it difficult for the gas G to diffuse into the catalyst. Therefore, in the example of the present disclosure, the reactor 10A is made compact, and sufficient insulation is provided for the first catalytic section 13 and the second catalytic section 21. This minimizes the radiation of heat generated by the combustion of the combustible gas and the oxidation of ammonia from the outer wall of the reactor 10A, thereby covering the heat absorbed by the ammonia decomposition reaction and achieving high hydrogen yield and thermal efficiency.

[0075] The first catalytic part 13 is disposed inside the housing 1, between the inlet 2 and the second catalytic part 21. By disposing the first catalytic part 13 in this position, the second catalytic part 21 can be heated by the heat generated by the catalytic reaction of the first catalytic part 13, and this heating can reform ammonia in the second catalytic part 21. This makes it possible to shorten the time until ammonia reforming (start-up time).

[0076] The first catalyst part 13 and the second catalyst part 21 are provided in the flow path 11 inside the housing 1. The first catalyst part 13 is provided on the upstream side of the gas flow in the flow path 11, and the second catalyst part 21 is provided on the downstream side of the gas flow in the flow path 11. Therefore, the gas G2 flowing out from the first catalyst part 13 flows into the second catalyst part 21.

[0077] The first catalyst section 13 includes a first catalyst. The first catalyst generates heat by burning (oxidizing) the combustible gas in the gas G1 introduced from the inlet 2. In the example of the present disclosure, the combustible gas is introduced from the inlet 2 together with ammonia. However, the combustible gas may be introduced from the inlet 2 separately from the ammonia. In the example of the present disclosure, first, the gas G1 containing ammonia and the combustible gas is introduced from the inlet 2, and the combustible gas is, for example, selectively combusted in the first catalyst section 13. As a result, the reaction gas containing ammonia is heated by the heat generated by the combustion of the combustible gas, and the reaction gas serves as a heat medium to heat the second catalyst section 21 in the subsequent stage.

[0078] As described above, it is preferable that no ammonia or only a very small amount of ammonia is burned by selectively burning the combustible gas in the first catalyst section 13. Therefore, for example, the combustible gas can be selectively burned by using a catalyst that can selectively burn the combustible gas or by setting the temperature (for example, 80°C or lower) at which the combustible gas can be selectively ignited (burned).

[0079] The type of flammable gas is not particularly limited as long as it is a gas other than ammonia and is easily combustible at room temperature (e.g., 30° C.), for example, flammable gases specified in the Container Safety Regulations (Ministry of International Trade and Industry Ordinance No. 50 of 1966), which is a Japanese law, as well as at least one type of alcohol gas (vapor) such as methanol, ethanol, or propanol.

[0080] In the example of the present disclosure, the first catalyst provided in the first catalyst section 13 is platinum, and the combustible gas is hydrogen. Therefore, the reaction shown in the following thermochemical reaction formula (11) proceeds: H ２ +1 / 2O ２ →H ２ O Heat generation ΔH = -284 kJ / mol ... (11)

[0081] The heat generated by combustion in the first catalyst part 13 is heat generated by the combustion of the combustible gas. Therefore, the amount of heat generated can be controlled by the amount of combustible gas burned, i.e., the amount of combustible gas in the gas G1. Therefore, by providing the first catalyst part 13 that burns the combustible gas, the amount of heat generated can be controlled and the heating temperature of the housing 1 can be suppressed.

[0082] The first catalyst section 13 is configured by disposing (packing) a particulate first catalyst on, for example, a porous plate. The particle diameter of the first catalyst is, for example, 1 mmφ or more and 10 mmφ or less.

[0083] FIG. 6 is a perspective view of the first catalyst section 13 and illustrates the size of the first catalyst section 13. FIG. 6 also illustrates the insulating material 12 surrounding the first catalyst section 13. For convenience, FIG. 6 depicts the insulating material 12 as having a rectangular shape, but this is not limited thereto. The first catalyst section 13 is cubic or rectangular (rectangular) and has a width W1, a depth D1, and a height H1. When the first catalyst section 13 is particulate, the width W1, depth D1, and height H1 of the entire particles when the particles are arranged (packed) in a rectangular shape are specified. When the first catalyst section 13 is a honeycomb catalyst, the distance between opposing outer surfaces of the honeycomb catalyst is the width W1, depth D1, and height H1.

[0084] H1 / W1 is, for example, 0.1 or more and 1.0 or less, preferably 0.3 or more and 0.7 or less. W1 / D1 is, for example, 0.5 or more and 2 or less, preferably 0.9 or more and 1.1 or less, and more preferably 1. The thickness T1 of the heat insulating material 12 in the portion surrounding the first catalyst section 13 is, for example, 50 mm or more and 300 mm or less, preferably 100 mm or more and 200 mm or less.

[0085] Returning to FIG. 5 , the inner wall of the housing 1 is provided with a thermal insulator 12. Different thermal insulators may be used in the vicinity of the inlet 2 and outlet 3 and in the portion housing the first catalyst section 13 and the second catalyst section 21. The thermal insulator 12 is made of a material that is heat-resistant and has excellent mechanical strength, and has some flexibility (elasticity). Therefore, although the thermal insulators 12 and 14 are made of different materials in the example of the present disclosure, they may be made of the same material by adjusting their shapes, for example. The thermal insulator 12 is made of, for example, a heat-resistant material having a filamentous or fibrous shape, specifically, for example, ceramic fiber or cement castable, but is not limited thereto. Note that the flexibility (elasticity) of the thermal insulator 12 in this embodiment is not as great as that of the thermal insulator 14 described later with reference to the third embodiment.

[0086] The reactor 10A includes a first distribution section 18A as shown in Fig. 5A and a second distribution section 18B as shown in Fig. 5D. As shown in Fig. 5A, the first distribution section 18A is installed between the first catalytic section 13 and the second catalytic section 21. By installing the first distribution section 18A between the first catalytic section 13 and the second catalytic section 21 in this manner, the gas G2 flowing out from the first catalytic section 13 is dispersed toward the second catalytic section 21.

[0087] Furthermore, by providing a first dispersion section 18A between the first catalyst section 13 and the second catalyst section 21 as shown in Figure 5A, it is possible to prevent the heat (gas G2) generated in the first catalyst section 13 from being transmitted only to the area directly below the first catalyst section 13, making it easier for the heat (gas G2) to come into uniform and even contact with the entire second catalyst section 21 located below the first catalyst section 13.

[0088] As shown in Fig. 5A, the first dispersion section 18A of the present disclosure provided between the first catalyst section 13 and the second catalyst section 21 may be configured to blow out the gas G2 obliquely downward from the center of the first catalyst section 13. In this case, the gas G2 may be blown out directly downward in addition to obliquely downward. Alternatively, a porous plate filled with particulate first catalyst 13 may also serve as the first dispersion section 18A. Alternatively, the first dispersion section 18A may be separately and independently installed below the first catalyst 13.

[0089] 5B and 5C are enlarged views of the X portion of the first dispersion section 18A in Fig. 5A, showing modified examples of the first dispersion section 18A. In Fig. 5B, the pores 18b are uniformly formed in the dispersion plate 18a that constitutes the first dispersion section 18A-1.

[0090] 5C, two types of holes (pores 18b-1 and 18b-2) are formed in the dispersion plate 18a that constitutes the first dispersion section 18A-2, with the small-diameter pores 18b-1 being formed on the central side and the large-diameter pores 18b-2 being formed on the peripheral side of the small-diameter pores 18b-1, thereby adjusting the aperture ratio. This may result in the outflow of gas G2 being more uniformly discharged on the peripheral side of the first dispersion section 18A-2 in the horizontal direction than on the central side.

[0091] 5D, the second dispersion section 18B in another example can be installed between the inlet 2 and the first catalyst section 13 to disperse the introduced gas G1 toward the first catalyst section 13. In the disclosure shown in FIG. 5D, the first dispersion section 18A is also installed, but if the dispersion conditions are good, the first dispersion section 18A may not be installed.

[0092] In addition, the second dispersion section 18B shown in Figure 5D may be provided above the first catalyst section 13 to form a uniform gas flow inside the second dispersion section 18B and minimize the temperature distribution in the arranged second catalyst section 21.

[0093] When the second dispersion section 18B is provided between the inlet 2 and the first catalyst section 13, for example, a basket filled with spherical or raschling-shaped filler material may be placed. Alternatively, a bottomed tube with openings on the side or bottom, or a member for adjusting the wind direction, such as a louver or wind direction plate, may be installed.

[0094] Furthermore, as shown in FIG. 5D of the present disclosure, a spherical wire mesh cage 18 filled with alumina balls 18d may be provided at a position where the flow path expands from the inlet 2 of the housing 1 (the bottom of the cage protrudes into the space of the flow path 11), and the rectified gas may pass through a packed bed formed of spherical alumina balls 18c, so that the rectified gas is dispersed from the inlet 2 to the expanding part of the reactor.

[0095] The reactor 10A includes a second catalyst section 21. The second catalyst section 21 has a honeycomb shape, and the specific structure of the second catalyst section 21 will be described later with reference to a third embodiment. The second catalyst section 21 is disposed between the first catalyst section 13 and the outlet 3 and includes a second catalyst. The second catalyst is heated by the heat generated in the first catalyst section 13 and generates hydrogen from ammonia contained in the gas G2.

[0096] The second catalyst supported on the second catalytic section 21 is a catalyst that reforms ammonia. Hydrogen is produced from ammonia through reforming. The specific components of the catalyst are not particularly limited as long as the catalyst is capable of reforming ammonia. For example, it is preferable that the catalyst contains a transition metal such as Ru, Co, Ni, Fe, or Pt as its main component.

[0097] 7 is a perspective view of the second catalyst section 21, illustrating the size of the second catalyst section 21. Insulators 12 and 22 surrounding the second catalyst section 21 are also shown in FIG.

[0098] The second catalyst section 21 is surrounded by multiple types of heat insulating materials 12, 22. The second catalyst section 21 is cubic or rectangular parallelepiped (rectangular) in shape and has a width W2, a depth D2, and a height H2. H2 / W2 is, for example, 0.5 to 3, preferably 0.8 to 2. W2 / D2 is, for example, 0.5 to 2, preferably 0.9 to 1.1, and more preferably 1. The total thickness T2 of the heat insulating materials 12, 22 surrounding the second catalyst section 21 is, for example, 50 mm to 300 mm, preferably 100 mm to 200 mm.

[0099] In the relationship between the first catalyst portion 13 and the second catalyst portion 21, W2 / W1 is, for example, 1 or more and 5 or less, preferably 2 or more and 3 or less. The first catalyst portion 13 and the second catalyst portion 21 are both covered on the sides with heat insulating material. The ratio (T1 / T2) of the thickness T1 of the heat insulating material covering the first catalyst portion 13 to the thickness T2 of the heat insulating material covering the second catalyst portion 21 is, for example, 1 or more and 3 or less, preferably 1 or more and 2 or less.

[0100] Returning to FIG. 5 , reforming in the second catalyst section 21 mainly proceeds in two stages. Specifically, for example, it includes partial oxidation of ammonia (reaction formula (12) below), an oxidation reaction of ammonia (reaction formula (13) below), and a decomposition reaction of ammonia (reaction formula (14) below). The reactions of reaction formulas (2) and (13) mainly proceed on the upper side (front stage) of the second catalyst section 21, and the reaction of reaction formula (14) mainly proceeds on the lower side (lower stage) of the second catalyst section 21. However, reforming does not necessarily proceed in two stages. NH ３ +1 / 4 O ２ →H ２ +1 / 2N ２ +1 / 2H ２ O Heat generation △H = -75 kJ / mol ... (12) NH ３ +3 / 4O ２ →1 / 2N ２ +3 / 20 ２　 Heat generation △H=-317kJ / mol...(13) NH ３ →3 / 2H ２ +1 / 2N ２　 Endotherm = +45.9kJ / mol…(14)

[0101] In particular, hydrogen is produced by the reaction of reaction formula (14), and a hydrogen-containing gas G3 is obtained.

[0102] FIG. 8 illustrates the temperature gradient between the second catalyst section 21 and the housing 1. For example, gas G2 at temperature T1 (e.g., approximately 630°C) reaches the second catalyst section 21 (particularly the second flow path 211). As a result of heat conduction within the end 213 of the second catalyst section 21, the temperature of the outer surface of the second catalyst section 21 drops to temperature T2 (e.g., approximately 450°C). Furthermore, the heat insulation 22 surrounding the second catalyst section 21 further impedes heat conduction, causing the temperature of the surface of the heat insulation 22 opposite the second catalyst section 21 to drop to temperature T3 (e.g., approximately 350°C). Finally, heat conduction is also impeded by the heat insulation 12, 22, causing the temperature of the surface of the heat insulation 12, 22 opposite the second catalyst section 21 to drop to temperature T4 (e.g., below 70°C). Finally, slight heat conduction occurs within the housing 1, causing the temperature at the outer surface of the housing 1 to drop to temperature T5 (e.g., below 50°C). Therefore, damage (oxidation, corrosion) caused by heat to the material (for example, carbon steel) that constitutes the housing 1 can be suppressed.

[0103] Compared to catalytic cracking, another technology for producing hydrogen from ammonia, ATR can achieve a higher GHSV, which is advantageous in terms of hydrogen production volume. However, the high GHSV results in a large pressure loss in the second catalyst section 21. In addition, the oxidation reaction in the second catalyst section 21 generates a large amount of heat, causing the inside of the reactor 10A to reach a high temperature of 600°C or higher.

[0104] In the ammonia decomposition reaction, lower pressure and higher temperature are advantageous from the standpoint of chemical equilibrium, as the reaction shifts toward the product (hydrogen). However, if the pressure loss is large, the inlet pressure of the reactor 10 is set high, which is unfavorable in terms of both chemical equilibrium and the compression energy of the gas G1 (raw material gas). However, higher temperatures are advantageous in terms of chemical equilibrium. However, by setting the temperature high, the reactor 10A (particularly the housing 1) is used in a temperature range where nitriding is likely to occur. Specifically, for example, at the internal temperature of the reactor 10, for example, in the temperature range of 500°C to 700°C, the nitrogen generated by the decomposition of ammonia promotes nitriding of iron, cobalt, molybdenum, etc., making the structures constituting the reactor 10 brittle. For this reason, it is necessary to use high-quality materials that are as resistant to nitriding as possible (e.g., "Inconel 600" (registered trademark) etc.) and keep the internal temperature of the reactor 10 low. This increases the cost of hydrogen production and makes it difficult for the ammonia decomposition reaction to proceed.

[0105] Therefore, in the reactor 10A of the present disclosure, in order to suppress heat radiation to the outside of the reactor 10 and to lower the temperature of the structures constituting the reactor 10 to a temperature lower than the nitriding temperature of approximately 600°C (for example, 450°C or lower), the side surfaces of the first catalyst section 13 are wrapped (covered) with a heat insulating material 12, and the side surfaces of the second catalyst section 21 are wrapped (covered) with heat insulating materials 12 and 22. This suppresses heat radiation through the side surfaces of the first catalyst section 13 and the second catalyst section 21, and makes it possible to lower the surface temperature (outside temperature) of the reactor 10 to a temperature lower than the nitriding temperature (for example, 80°C or lower).

[0106] FIG. 9 shows a structure for starting the reactor 10A using at least a portion of the hydrogen generated in the second catalyst section 21. The reactor 10A includes a heat exchanger 51, a tank 52, a pump 53, an outlet flow path 54, and a return flow path 54b. The tank 52 stores hydrogen generated in the second catalyst section 21 and discharged from the outlet 3. The hydrogen discharged from the outlet 3 is cooled to, for example, 40°C or less by cooling water CW in the heat exchanger 51 and flows into the tank 52. The tank 52 is provided in the outlet flow path 54 and stores the discharged hydrogen. The outlet flow path 54 discharges hydrogen from the outlet 3 and is, for example, a pipe. The return flow path 54b branches from a branching portion 54a of the outlet flow path 54 and returns hydrogen to the inlet 2 and is, for example, a pipe. The hydrogen in the tank 52 is returned to the inlet 2 by the operation of the pump 53. The return flow path 54b is provided with a valve 54c for regulating the flow rate of hydrogen. The hydrogen from the outlet passage 54 is used as a product.

[0107] The initial start-up of the reactor 10A is performed using a combustible gas (e.g., hydrogen in a hydrogen cylinder) stored in a separately installed cylinder or the like. As the reforming progresses, hydrogen is generated in the second catalyst section 21 as shown in reaction formula (4), and the generated hydrogen is stored in the tank 52. When the reactor 10A is started up, some or all of the hydrogen stored in the tank 52 is used as the combustible gas. This eliminates the need for a cylinder or the like when starting up the reactor 10 for the second time or later.

[0108] Fig. 10 is a graph showing an example of the temperature distribution inside the reactor 10 when combustible gas is combusted in the first catalytic section 13 under specific reaction conditions in the first embodiment. The graph shown in Fig. 10 shows the temperature distribution at the start of the reactor 10 for ammonia reforming. The horizontal axis represents the height position (cm) from the upper end of the first catalytic section 13 toward the second catalytic section 21 (downstream in the gas flow), and the vertical axis represents the temperature. For reference, the first catalytic section 13 and the second catalytic section 21 are shown at corresponding positions among the height positions shown on the horizontal axis of Fig. 10.

[0109] The reaction conditions are as follows: ３In the reactor 10 that produces hydrogen at 1000kJ / hr, an alumina catalyst (3 mmφ spherical) carrying 2 wt % platinum was used as the first catalyst section 13. A honeycomb catalyst (W1 = 150 mm, D1 = 150 mm, H1 = 50 mm) carrying cobalt was used as the second catalyst section 21. The width ratio: W2 / W1 was 1, and the thickness ratio of the heat insulating material: T1 / T2 was 1. The first catalyst section 13 was disposed between the inlet 2 and the second catalyst section 21 in a portion having the same cross-sectional area as the second catalyst section 21. Specifically, the horizontal cross-sectional areas of both the first catalyst section 13 and the second catalyst section 21 were 300 mm x 300 mm = 90,000 mm. ２ The amount of the first catalyst packed was 3 L, and the amount of the second catalyst packed was 40.5 L.

[0110] After hydrogen reduction at 600°C, the flow rates of ammonia and oxygen in gas G1 were set to 250 Nm ３ / hr, 40Nm ３ / hr, plus 10 Nm of hydrogen ３ / hr was added and supplied to the first catalyst section 13 (startup of the reactor 10). The temperature distribution in the first catalyst section 13 and the second catalyst section 21 at this time is shown in FIG.

[0111] When gas G1 is introduced and ignited in first catalytic section 13, the heat of combustion of hydrogen causes a rapid rise in the temperature in first catalytic section 13. The temperature near the outlet of first catalytic section 13 then reaches a temperature of, for example, about 180°C to 300°C, at which the partial oxidation reaction of ammonia (the reaction represented by reaction formula (2)) that proceeds near the inlet of second catalytic section 21 in the subsequent stage can proceed.

[0112] The interior of the reactor 10B is insulated by heat insulating materials 12, 22, etc. For example, the second catalyst section 21 is heated by the inflow of gas G2, which has reached a temperature of approximately 200°C or higher. At the same time, the partial oxidation reaction and oxidation reaction of ammonia, represented by reaction formulas (2) and (3), proceed near the inlet of the second catalyst section 21. Because these are exothermic reactions, the temperature of the gas G flowing through the second catalyst section 21 further increases, and the temperature of the flowing gas G increases, for example, to 600°C or higher. However, toward the downstream side of the second catalyst section 21, the ammonia decomposition reaction (hydrogen production reaction), represented by reaction formula (4), becomes dominant. Therefore, the temperature of the gas G flowing through the second catalyst section 21 begins to decrease.

[0113] Fig. 11 is a graph showing the temperature distribution inside the reactor 10 when ammonia reforming is performed in the reactor 10A without adding a combustible gas. The graph shown in Fig. 11 is a graph when ammonia reforming is performed using the second catalyst part 21 that has already been heated as shown in the graph of Fig. 10.

[0114] The temperature of the second catalyst section 21 is already about 600°C to 700°C in an adiabatic state. For this reason, when gas G1 containing, for example, ammonia (but not hydrogen) and at about 30°C (room temperature) is introduced, the gas G1 passes through the first catalyst section 13 without igniting and flows into the second catalyst section 21 as gas G2. The gas G (gas G1) that has flowed into the second catalyst section 21 undergoes a reaction in the second catalyst section 21, which has been heated to about 600°C to 700°C.

[0115] For example, when gas G2 at about 30°C flows into the second catalytic section 21, the temperature near the inlet of the second catalytic section 21 may drop. However, the reaction that proceeds near the inlet of the second catalytic section 21 (the reaction shown in reaction formulas (12) and (13)) is an exothermic reaction. Therefore, even if a relatively low-temperature gas G2 flows in, the temperature of the second catalytic section 21 hardly drops. Therefore, the temperature of the second catalytic section 21 is maintained high in an adiabatic state, and the ammonia decomposition reaction continues as shown in FIG. 11 even without the addition of a flammable gas.

[0116] FIG. 12 is a flowchart showing a hydrogen production method (hereinafter referred to as the production method of the present disclosure). The production method shown in FIG. 12 can be performed using, for example, the reactor 10 (FIG. 5). Therefore, the description of FIG. 12 will be made with reference to FIG. 5 as appropriate. For convenience, FIG. 12 illustrates hydrogen as an example of the combustible gas. The production method of the present disclosure also includes an ammonia reforming method and includes steps S1 to S4. As shown in FIG. 12, step S1 (introduction step) is a step of introducing a gas G1 (introduced gas) containing ammonia and a combustible gas other than ammonia into the reactor 10A. This causes the hydrogen to combust in the first catalyst section 13, heating the second catalyst section 21. The amount of combustible gas added to ammonia is not particularly limited, but is, for example, 0.02 to 0.06 moles, preferably 0.03 to 0.05 moles, of the combustible gas (e.g., hydrogen) per mole of ammonia.

[0117] Step S2 (heating step, combustion step) is a step in which combustible gas in the introduced gas G1 is selectively combusted by the first catalyst. Combustion can be performed, for example, by igniting the gas G1 in the first catalyst section 13. Also, selective combustion of the combustible gas can be performed, for example, by setting the temperature of the gas G1 to a temperature equal to or higher than the ignition temperature of the combustible gas and lower than the ignition temperature of ammonia.

[0118] Step S2 (heating step, combustion step) is a step of further heating the second catalytic section 21 (an example of a second catalyst) by, for example, heat generated by burning the combustible gas in the first catalytic section 13. As described above, the second catalytic section 21 is a catalytic section that generates hydrogen from ammonia. By heating the second catalytic section 21, the second catalytic section 21 is heated to a predetermined temperature. The predetermined temperature is not particularly limited, but is preferably a temperature at which the reactions of the above reaction formulas (12) to (14) can proceed. Furthermore, raising the temperature to the predetermined temperature can be performed by appropriately adjusting the concentration of the combustible gas in the gas G1.

[0119] Step S3 (reforming step) is a step in which the introduction of the combustible gas (hydrogen) is stopped after the temperature of the second catalyst section 21 (an example of a second catalyst) reaches a predetermined temperature. Since the introduction of the combustible gas (hydrogen) is stopped, the combustible gas (hydrogen) is no longer supplied to the first catalyst section 13, and combustion of the combustible gas (hydrogen) in the first catalyst section 13 is stopped.

[0120] Step S4 (reforming step) is a step of generating hydrogen from ammonia using the second catalyst section 21. The introduction of the combustible gas (hydrogen) can be stopped while continuing the introduction of the gas G1 containing ammonia. However, the introduction of the combustible gas may also be stopped by stopping the introduction of the gas G1 containing ammonia and the combustible gas (hydrogen), and then introducing the gas G1 containing ammonia but not the combustible gas (hydrogen).

[0121] When the introduction of the combustible gas is stopped, the gas G1 containing ammonia and oxygen does not react in the first catalytic section 13 and is supplied as gas G2 to the second catalytic section 21. Immediately after the introduction of the combustible gas is stopped, the gas G2 contains products produced by the combustion of the combustible gas in the first catalytic section 13. When the combustible gas is hydrogen, for example, the products are water.

[0122] The reaction pressure in the second catalytic section 21 (particularly the pressure at which the reactions of reaction formulas (2) and (3) proceed) is, for example, 0.02 MPaG to 0.6 MPaG, preferably 0.05 MPaG to 0.3 MPaG. The reaction temperature is, for example, 180°C to 800°C, preferably 200°C to 650°C. The oxygen content in the gas G2 supplied to the second catalytic section 21 is, for example, 0.1 mol to 0.2 mol, preferably 0.12 mol to 0.16 mol per mol of ammonia. Oxygen is also consumed in the first catalytic section 13 installed upstream of the second catalytic section 21. Therefore, it is preferable to determine the amount of oxygen in the gas G1 introduced into the reactor 10, taking into account the amount of oxygen consumed in both the first catalytic section 13 and the second catalytic section 21.

[0123] The above points can be summarized as follows: In the present disclosure, combustible gas (hydrogen) is combusted in the first catalytic section 13. This causes the temperature of the second catalytic section 21 to rise to a temperature at which an oxidation reaction of ammonia can be initiated. Then, hydrogen is produced by the oxidative decomposition of ammonia in the second catalytic section 21.

[0124] In boilers and heating furnaces that are frequently started and stopped, the reaction gas must be preheated to 200°C or higher before each start-up. Conventionally, a heater (e.g., an electric heater or burner) was required for this heating, and it took time to heat up the reaction gas. Therefore, in the present disclosure, when a combustible gas such as hydrogen and oxygen are added to gas G1 (reaction gas), a combustion reaction proceeds in the first catalyst section 13 from room temperature (e.g., 30°C). This heat generation raises the temperature of gas G1 in the reactor 10 to a temperature at which the ammonia oxidation reaction begins in the downstream second catalyst section 21. This eliminates the need for a heating furnace and allows for a faster temperature rise response. This is because the reaction gas can be heated directly, rather than indirectly from the outside.

[0125] In addition, in the present disclosure, the second catalyst part 21 is a honeycomb catalyst having a honeycomb shape, which improves the insulating properties of the second catalyst part 21 and the housing 1, and suppresses the dissipation of heat generated by the combustion of combustible gas in the first catalyst part 13 and the heat generated by the oxidation of ammonia in the second catalyst part 21.

[0126] The main subject of this disclosure is "hydrogen production capacity of 10 Nm ３ / hr~2,000Nm ３In small- to medium-sized reactors (e.g., 1 / hr), the ratio of the reactor's outer surface area to the catalyst unit volume is large. This facilitates heat dissipation, lowering the temperature of the gas G and resulting in a lower ammonia decomposition rate. On the other hand, thickening the insulation material 12 increases the outer diameter of the reactor 10, hindering the compactness of the small-scale device. Alternatively, a large amount of oxygen must be supplied to maintain the temperature equivalent to the heat dissipation, resulting in a decrease in the hydrogen yield. Therefore, a honeycomb catalyst is used in this disclosure. Because no reaction occurs on the outer surface of the honeycomb in a honeycomb catalyst, no heat is generated on the surface in contact with the inner surface of the reactor 10 (the surface of the insulation material 12). Furthermore, because the outer wall of the honeycomb is ceramic, the catalyst itself has excellent thermal insulation properties. This allows for both compactness and improved hydrogen yield.

[0127] Furthermore, in the present disclosure, the first catalyst part 13 and the second catalyst part 21 are arranged in a portion having the same cross-sectional area (a locally expanding portion inside the housing 1). This makes it possible to suppress heat dissipation. Furthermore, as will be described in detail later with reference to the second embodiment, the first catalyst part 13 is arranged between the inlet 2 and the upper end of the locally expanding portion formed below the inlet 2. This makes it possible to increase the thickness T1 of the heat insulating material 12 covering the first catalyst part 13, thereby significantly suppressing heat dissipation from the first catalyst part 13.

[0128] Furthermore, in the present disclosure, the sizes of the first catalytic section 13 and the second catalytic section 21 are set as described above. Producing hydrogen from ammonia to achieve carbon neutrality requires high thermal efficiency during the production process. Therefore, the reactor 10A must meet the following requirements: high insulation, low pressure loss, and high one-pass conversion. To reduce pressure loss and improve insulation, H1 / (W1×D1) and H2 / (W2×D2) should be small. However, if these values ​​are too small, the flow rate of gas G decreases, making it difficult for gas G to diffuse into the first catalytic section 13 and the second catalytic section 21, resulting in a decrease in the ammonia conversion rate. Furthermore, the uniformity of the gas G dispersion is impaired, resulting in uneven flow and a decrease in the ammonia decomposition rate. Therefore, in the present disclosure, the sizes of the first catalytic section 13 and the second catalytic section 21 are optimized and set as described above, thereby improving the ammonia decomposition efficiency.

[0129] According to this embodiment, a reactor and a method for producing hydrogen with high thermal efficiency that can quickly respond to load fluctuations and start-up / shutdown on the demand side X can be provided, and the obtained hydrogen can be sent to, for example, a boiler, an industrial furnace, etc. for use.

[0130] [Sixth Embodiment] Figure 13 is a cross-sectional view showing the internal structure of a reactor 10B according to a sixth embodiment. Note that components identical to those in the fifth embodiment are denoted by the same reference numerals, and their description will be omitted. In the sixth embodiment, the first catalyst section 13 is installed near the inlet 2, unlike the first embodiment. Therefore, the first catalyst section 13 is disposed in a portion having a smaller horizontal cross-sectional area than the cross-sectional area of ​​the installation location of the second catalyst section 21. Furthermore, the shape between the inlet 2 and the upper end of the locally widened portion formed below the inlet 2 is a rectangular tube (rectangular in top view). However, the shape of the inlet 2 may also be cylindrical (circular in top view).

[0131] A dispersion section 18 is provided below the first catalyst section 13, and the lower surface of the dispersion section 18 is located in the locally widened portion. The thickness T1 of the insulating material 12 surrounding the first catalyst section 13 in the second embodiment is longer than the thickness T1 of the insulating material 12 surrounding the first catalyst section 13 in the first embodiment. Furthermore, in the second embodiment, the shape of the first catalyst section 13 is honeycomb-shaped, unlike the first embodiment. Therefore, the first catalyst section 13 is a honeycomb catalyst, similar to the second catalyst section 21. The specific structure of the first catalyst section 13 will be described later with reference to the third embodiment.

[0132] The experiment shown in FIG. 10 was also conducted for the sixth embodiment to verify its effectiveness. The experimental conditions were as follows: the first catalyst portion 13 was a honeycomb catalyst supporting platinum. The honeycomb catalyst had dimensions of width W1 = 150 mm, depth D1 = 150 mm, and height H1 = 50 mm. The amount of the first catalyst packed was 2.25 L. The other experimental conditions were the same as those shown in FIG. 10. The cross-sectional area of ​​the first catalyst portion 13 was 150 mm x 150 mm, W2 / W1 = 2, and T1 / T2 = 1.4.

[0133] Even when verified under such experimental conditions, the same effect as in the fifth embodiment (temperature distribution shown in FIG. 10) was obtained.

[0134] Seventh Embodiment Figure 14 is a cross-sectional view showing the internal structure of a reactor 10C according to a seventh embodiment. Components identical to those in the fifth and sixth embodiments are designated by the same reference numerals, and their description will be omitted. In the seventh embodiment, the housing 1 has an enlarged portion 17 between the inlet 2 and the second catalyst section 21, in which the cross-sectional area of ​​the flow path 11 formed inside the housing 1 expands toward the downstream side of the gas flow. The thermal insulator 12 is disposed along the inner surface of the housing 1, and the thickness of the thermal insulator 12 is the same regardless of the location. Therefore, the cross-sectional area of ​​the flow path 11 defined by the thermal insulator 12 expands in the enlarged portion 17 of the housing 1.

[0135] The first catalyst section 13 is disposed in the expansion section 17. By disposing the first catalyst section 13 in this position, the heated gas G2 generated in the first catalyst section 13 spreads downward along the heat insulating material 12. This makes it possible to prevent the heated gas G2 from being blown against the heat insulating material 12, and to prevent heat from being released to the outside of the reactor 10 through the heat insulating material 12.

[0136] In the example of the present disclosure, the first catalyst section 13 is installed inside the expansion section 17. Because both the first catalyst section 13 and the cylindrical body 15 have a rectangular shape, the size of the gap 16 increases the further downstream the gas flow is. In the first catalyst section 13, the temperature increases due to heat generated in the first flow path 131 the further downstream the gas flow is, so by making the gap 16 larger the further downstream the gas flow is, the insulating effect due to the presence of a gas phase can be increased.

[0137] By installing the first catalyst section 13 inside the reactor 10, for example, near the inlet 2, it is possible to prevent heat generated by the combustion of the combustible gas from being unintentionally released to the outside, and to raise the temperature of the gas G2 supplied to the second catalyst section 21 to a temperature effective for ammonia reforming (for example, 200°C or higher). This makes it possible to prevent damage to the reactor 10 (particularly the casing 1) due to heat. Furthermore, in order to perform ammonia reforming, the reactor 10 can be quickly started up (prepared before ammonia reforming).

[0138] The first catalyst section 13 is disposed with a gap 16 between it and the surface 121 of the thermal insulator 12. The surface 121 faces the flow path 11 (the surface that defines the flow path 11) and is the surface that comes into contact with the gas G flowing inside the reactor 10. Therefore, because gas G is present in the gap 16, a gas phase exists between the thermal insulator 12 and the first catalyst section 13. This makes it difficult for heat generated in the first catalyst section 13 to be transferred to the thermal insulator 12. While the thermal insulator 12 has an insulating effect, some heat transfer (heat dissipation to the outside) may occur. Therefore, by using the gap 16 to avoid thermal contact between the first catalyst section 13 and the thermal insulator 12 (including contact via the solid cylindrical body 15), heat dissipation to the outside of the reactor 10 is suppressed, allowing for effective use of heat. Furthermore, thermal damage to the housing 1 can be suppressed.

[0139] The first catalyst section 13 is, for example, a honeycomb catalyst having a honeycomb shape, and has a first flow path 131 that is rectangular, for example, when viewed from above (not shown). However, the first flow path 131 may also be circular, honeycomb-shaped, or hexagonal. The first catalyst section 13 has a rectangular shape (cubic, rectangular parallelepiped, etc.) with a certain thickness. The first catalyst section 13 includes the first flow path 131 and a first holder 132. The first flow path 131 is a flow path that follows the gas flow (gas flow in the flow path 11) formed between the inlet 2 and the outlet 3. The flow paths of the second catalyst section 21 of the first embodiment and the first catalyst section 13 and second catalyst section 21 of the second embodiment may also be circular, honeycomb-shaped, or hexagonal, for example.

[0140] The first holder 132 is a holder that partitions the first flow path 131 and holds the first catalyst. By providing the first catalyst section 13 with the first flow path 131 and the first holder 132, a catalytic reaction can proceed with the gas G flowing through the first flow path 131 without significantly increasing the pressure loss of the gas G flowing through the flow path 11. More specifically, by suppressing the pressure loss of the first catalyst section 13 (pressure loss is proportional to the square of the linear velocity) while increasing the GHSV of the gas G flowing through the first catalyst section 13 as much as possible, the amount of the first catalyst used can be reduced and the reactor 10 can be made more compact.

[0141] The method for supporting the first catalyst on the first holder 132 is not particularly limited. In the example of the present disclosure, for example, a raw material containing a binder (e.g., clay powder) can be extruded into the shape of the first catalyst portion 13, and the catalyst component can be supported after firing. For example, in the first catalyst portion 13 manufactured in this manner, the gas G1 flowing through the first flow path 131 diffuses into the first holder 132, and a catalytic reaction progresses inside the first holder 132 near the first flow path 131. However, the first catalyst may also be supported on, for example, the surface of the first holder 132 so as to face the first flow path 131.

[0142] The number of first flow paths 131 is not particularly limited. For example, when viewed from above the first catalyst section 13 (when the first catalyst section 13 is viewed from the inlet 2), the number of first flow paths 131 is 645.16 mm. ２ (1 inch ２ The number of cells in the first flow paths 131 per first catalyst section 13 is 200 to 2,000, preferably 400 to 1,200. The first flow paths 131 have the same cross-sectional area throughout the thickness direction of the first catalyst section 13 and extend linearly in the vertical direction. The first flow paths 131 are also regularly arranged at equal intervals.

[0143] The first flow path 131 is formed in a first holder 132. In the first catalyst section 13, the thickness of the corner wall (peripheral wall thickness) surrounding the first flow path 131, i.e., the thickness of the first end 133 (the end formed on the side of the first flow path 131) of the first holder 132, is thicker than the distance between adjacent first flow paths 131. A flammable gas such as hydrogen flows through the first flow path 131, and combustion of the flammable gas progresses in the first flow path 131. As a result, the first flow path 131 becomes hot (e.g., 150°C to 250°C, e.g., approximately 200°C), and heat generated in the first catalyst section 13 is supplied to the second catalyst section 21 in the subsequent stage. Therefore, even if some heat radiation to the housing 1 is unavoidable, it is preferable to suppress the amount of heat unintentionally radiated from the first catalyst section 13 to the outside of the reactor 10 (heat radiation amount).

[0144] The sides of the first catalyst part 13 are surrounded by, for example, flexible (elastic) heat insulating material 14. This can promote the inflow and outflow of gas G and suppress heat radiation to the sides. In particular, since the housing 1 is present on the sides of the first catalyst part 13, the heat insulating material 14 can suppress heat radiation to the housing 1. The heat insulating material 14 is made of, for example, a heat-resistant material having a filamentous or fibrous shape, and specifically, for example, rock wool, but is not limited to this.

[0145] The first catalyst section 13 is housed in, for example, a cylindrical body 15 having a bottom. The dispersion section 18 is provided on the bottom surface of the cylindrical body 15. As described above, the inlet 2 is formed in the housing 1, and the cylindrical body 15 is housed so as to fit into the inlet 2. Therefore, the gas G1 introduced through the inlet 2 flows into the cylindrical body 15, and then flows inside the cylindrical body 15, which also serves as the flow path 11.

[0146] The cylindrical body 15 includes a main body 151 that houses the first catalyst section 13. The outer shape of the main body 151 (e.g., a square tube, a cylinder, etc.) matches the shape of the inlet 2 (e.g., a rectangle, a circle, etc.).

[0147] A heat insulating material 14 is provided between the inner wall surface 154 of the cylindrical body 15 and the side surface 134 of the first catalyst section 13. The heat insulating material 14 is arranged so as to fill the space between the inner wall surface 154 and the side surface 134 as closely as possible. Furthermore, since the heat insulating material 14 is provided between the inner wall surface 154 and the side surface 134, the gas G1 introduced from the inlet 2 flows into the first flow path 131 without passing between the inner wall surface 154 and the side surface 134.

[0148] In this way, by disposing the heat insulating material 14 between the inner wall surface 154 and the side surface 134, a heat insulating effect is obtained. Furthermore, the first end 133 of the heat insulating material 14 is disposed so as to surround the first flow path 131, and heat is not generated at the first end 133 where the gas G1 does not flow, or outside the first end 133. Furthermore, the first end 133 makes it difficult for heat generated in the first flow path 131 to be transferred to the outside. Therefore, it is possible to suppress unintentional heat dissipation to the outside of the reactor 10 and to improve the heat utilization efficiency. It is also possible to suppress damage to the housing 1 due to heat.

[0149] The second catalyst section 21 is constructed by arranging a plurality of (e.g., four) unit second catalyst sections 215 horizontally in a square shape and stacking them vertically in a plurality of tiers (e.g., eight tiers). By constructing the second catalyst section 21 from a combination of a plurality of unit second catalyst sections 215 in this manner, the shape of the second catalyst section 21 can be flexibly changed to suit the design conditions, such as the shape and size of the second catalyst section 21, and the placement location, etc. However, the second catalyst section 21 does not need to be constructed from a plurality of unit second catalyst sections 215, and may be constructed in a single shape. Furthermore, the second catalyst section 21 is not limited to a rectangular shape (prism), and may be, for example, a round shape (cylinder), etc.

[0150] The unit second catalyst portion 215 is the same as the first catalyst portion 13 except for the supported catalyst. Therefore, the explanations (manufacturing method, dimensions, shape, etc.) for the first catalyst portion 13 can also be applied to the unit second catalyst portion 215.

[0151] FIG. 15 is a cross-sectional view taken along line A-A in FIG. 140, showing the second catalyst section 21 installed in the second stage. For example, the rectangular second catalyst section 21 is arranged inside the cylindrical housing 1, in the center of the housing 1 when viewed from above. The housing 1 may also be rectangular (cylindrical with corners). The insulating material 22 is wrapped around the second catalyst section 21 in the same manner as the first catalyst section 13. The insulating material 22 is the same as the insulating material 14, except that it is wrapped around a different object. Furthermore, the insulating material 12 is arranged on the outside of the insulating material 22, in the same manner as the first catalyst section 13.

[0152] Returning to FIG. 14 , the second catalyst section 21 is a honeycomb catalyst having a honeycomb shape, similar to the first catalyst section 13. In the illustrated example, the honeycomb shape has second flow paths 211 that are rectangular in top view, but the second flow paths 211 may also have, for example, a circular, honeycomb, or hexagonal shape. The second catalyst section 21 includes the second flow paths 211 and a second holder 212. The second flow paths 211 (second flow path) are flow paths along the gas flow (gas flow in the flow path 11) formed between the inlet 2 and the outlet 3. In the example of the present disclosure, the second flow paths 211 have the same cross-sectional area throughout the thickness direction of the second catalyst section 21 and extend linearly in the vertical direction. Furthermore, the second flow paths 211 are regularly arranged at equal intervals.

[0153] The second holder 212 is a holder that partitions the second flow path 211 and holds the second catalyst. With the second catalyst section 21 having such a structure, a catalytic reaction can proceed with the gas G flowing through the second flow path 211 without significantly increasing the pressure loss of the gas G flowing through the flow path 11. As a result, by suppressing the pressure loss of the second catalyst section 21 (pressure loss is proportional to the square of the linear velocity) while increasing the GHSV of the gas G flowing through the second catalyst section 21 as much as possible, the amount of catalyst used can be reduced and the reactor 10 can be made compact.

[0154] The second flow path 211 is formed in the second holder 212. The thickness of the end 213 (the lateral end of the second flow path 211) of the second holder 212 is thicker than the distance between adjacent second flow paths 211 so as to surround the second flow path 211. An exothermic reaction, described below, proceeds in the second flow path 211. As a result, the second flow path 211 reaches a high temperature (e.g., 600°C or higher and 800°C or lower), and heat generated in the first catalyst section 13 is supplied to the downstream second catalyst section 21. Therefore, even if some heat radiation to the housing 1 is unavoidable, it is preferable to suppress the amount of heat unintentionally radiated from the first catalyst section 13 to the outside of the reactor 10 (heat radiation amount). Therefore, similar to the first catalyst section 13, providing the end 213 can suppress heat radiation to the outside.

[0155] In the seventh embodiment, an experiment similar to that shown in FIG. 10 was also conducted to verify the effects. The experimental conditions were the same as those of the second embodiment except that T1 / T2 = 1. Even when verified under these experimental conditions, the same effects as those of the fifth embodiment (temperature distribution shown in FIG. 10) were obtained.

[0156] The present invention can be applied to all ammonia-hydrogen mixed fuel production devices.

[0157] 1010A to 1010D Ammonia-hydrogen mixed fuel production apparatus 1011 Air 1013 Oxygen separation device 1014 Raw material supply section 1015 Reforming reactor 1016 Reformed gas 1017 Gas component analyzer 1018 Fuel 1 Housing 10A, 10B, 10C Reactor 11 Flow path 12 Heat insulating material 121 Surface 13 First catalyst section 131 First flow path 132 First holder 133 First end 134 Side surface 14 Heat insulating material 15 Cylinder 151 Main body 154 Inner wall surface 16 Gap 17 Expanded section 18A First dispersion section 18B Second dispersion section 2 Inlet 21 Second catalyst section 211 Second flow path 212 Second holder 213 End 215 Second catalyst unit section 22 Heat insulating material 3 Outlet 51 Heat exchanger 52 Tank 53 Pump 54 Outlet flow path 54a Branching section 54b Return flow path S1 Step (introduction step) S2 Step (heating step) S3 Step (reforming step) S4 Step (reforming step)

Claims

1. An apparatus for producing an ammonia-hydrogen mixed fuel, comprising: an oxygen supply unit that supplies oxygen at a desired concentration; a reforming reactor that converts ammonia to hydrogen using oxygen at the desired concentration from the oxygen supply unit to produce a reformed gas; and a gas component analyzer that measures the concentration of either hydrogen or ammonia, or both, in the reformed gas from the reforming reactor.

2. The ammonia / hydrogen mixed fuel production apparatus according to claim 1, wherein the oxygen supply unit is an oxygen separation device which separates oxygen from air to a desired concentration.

3. The ammonia / hydrogen mixed fuel production device according to claim 1, characterized in that the oxygen supply unit is an air dryer that removes moisture from the supplied air.

4. The ammonia / hydrogen mixed fuel production device according to claim 1, characterized in that the oxygen supply unit adds 3 to 20 volume % of oxygen to the amount of the ammonia supplied.

5. An ammonia / hydrogen mixed fuel production device as described in claim 1 or 2, characterized in that the amount of oxygen supplied from the oxygen supply unit is controlled based on the concentration of either or both of the hydrogen and the ammonia from the gas component analyzer.

6. An ammonia / hydrogen mixed fuel production device as described in claim 1 or 2, characterized in that a bypass line for supplying the ammonia from the raw material supply unit is provided between the reforming reactor and the measurement location of the gas component analyzer downstream of the reforming reactor.

7. An ammonia / hydrogen mixed fuel production device as described in claim 1 or 2, characterized in that it comprises: a bypass line for supplying ammonia from a raw material supply unit between the reforming reactor and a measurement point of the gas component analyzer on the downstream side of the reforming reactor; and a storage tank provided between the ammonia introduction position of the bypass line and the reforming reactor, and adjusts the gas composition of the reformed gas and ammonia according to the composition ratio of ammonia and hydrogen in the gas component analyzer and a required fuel composition ratio.

8. The apparatus for producing ammonia and hydrogen mixed fuel as described in claim 1, characterized in that the reforming reactor comprises: a housing having an inlet for introducing ammonia and a combustible gas other than ammonia, and an outlet for discharging a generated gas; a first catalyst unit disposed inside the housing and having a first catalyst that generates heat by burning the combustible gas introduced from the inlet; and a second catalyst unit disposed between the first catalyst unit and the outlet, heated by the heat generated by the first catalyst unit, and having a second catalyst that generates hydrogen from ammonia.

9. The ammonia and hydrogen mixed fuel production device according to claim 8, characterized in that the first catalyst section is disposed between the inlet and the second catalyst section.

10. The ammonia and hydrogen mixed fuel production device according to claim 8, characterized in that the reactor is provided with a dispersion section between the first catalyst section and the second catalyst section, which disperses the gas flowing out from the first catalyst section toward the second catalyst section.

11. The ammonia and hydrogen mixed fuel production device as described in claim 8, characterized in that it comprises: an outlet flow path for discharging hydrogen from the outlet; a tank provided in the outlet flow path for storing the discharged hydrogen; and a return flow path branched off from a branching portion of the outlet flow path and for returning the hydrogen to the inlet.

12. A fuel supply system using the ammonia / hydrogen mixed fuel production device according to claim 1 or 2, for supplying ammonia reformed fuel to a fuel demand section.

13. A method for producing hydrogen comprising: an introduction step of introducing an introduction gas containing ammonia and a combustible gas other than ammonia into a reactor; a combustion step of selectively combusting the combustible gas in the introduced introduction gas with a first catalyst; a second catalyst heating step of heating a second catalyst that generates hydrogen from ammonia with heat generated in the combustion step; and a reforming step of stopping the introduction of the combustible gas after the temperature of the second catalyst reaches a predetermined temperature, and generating hydrogen from ammonia using the second catalyst.

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