Ammonia supply systems, hydrogen production systems, carbon-free power generation systems, and fuel cell systems

Abstract

We provide ammonia supply systems, hydrogen production systems, carbon-free power generation systems, and fuel cell systems with improved reaction reliability and energy efficiency. [Solution] The ammonia supply system includes an ammonia supply unit; an ammonia demand unit; a connecting line connecting the ammonia supply unit and the ammonia demand unit; a hydrogen supply unit; and one or more first hydrogen supply lines connecting the hydrogen supply unit and the connecting line to supply a hydrogen gas stream, wherein the connecting line includes a first pipe controlled to an average temperature of 410°C or less and a second pipe controlled to an average temperature of over 410°C, and the second pipe includes a nickel-based alloy (NT) that satisfies the following formula 1. [Formula 1] T≦15μm T is the maximum nitrided depth when a cylindrical specimen of NT is exposed to a gas stream containing NH3, H2, and N2 in a 500°C environment for 100 hours.

Description

[Technical Field]

[0001] The disclosures of this application relate to ammonia supply systems, hydrogen production systems, carbon-free power generation systems, and fuel cell systems. [Background technology]

[0002] In various industrial sectors, hydrocarbon fossil fuels such as coal and oil are used as energy sources. However, hydrocarbon fossil fuels are limited in quantity and face the problem of future depletion, as well as the problem of accelerating climate change and global warming by continuously emitting carbon during combustion.

[0003] Therefore, there is a growing global need for new, renewable, and environmentally friendly energy sources, and interest in ammonia as such an energy source is increasing. [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] One objective of this disclosure is to provide an ammonia supply system with improved reaction reliability and energy efficiency.

[0005] One objective of this disclosure is to provide a hydrogen production system with improved reaction reliability and energy efficiency.

[0006] One of the objectives of this disclosure is to provide a carbon-free power generation system with improved reaction reliability and energy efficiency.

[0007] One objective of this disclosure is to provide a fuel cell system with improved reaction reliability and energy efficiency. [Means for solving the problem]

[0008] An ammonia supply system according to an embodiment of the present disclosure includes an ammonia supply unit; an ammonia demand unit; a connecting line connecting the ammonia supply unit and the ammonia demand unit; a hydrogen supply unit; and one or more first hydrogen supply lines connecting the hydrogen supply unit and the connecting line and supplying a hydrogen gas stream, wherein the connecting line includes a first pipe controlled to an average temperature of 410°C or less and a second pipe controlled to an average temperature of over 410°C, and the second pipe is made of a nickel-based alloy (N) satisfying the following formula 1. T ) can include

[0009] [Formula 1] T ≤ 15 μm

[0010] In the above formula 1, T is the nickel alloy (N T A cylindrical specimen with a cross-sectional diameter of 2 mm and a height of 200 mm is prepared. When the cylindrical specimen is exposed to a gas stream containing 97.2 volume% NH3, 2.1 volume% H2, and 0.7 volume% N2, and a temperature environment of 500°C for 100 hours, the maximum depth of nitrided material is obtained from the side of the cylindrical specimen in the direction of the central axis. This depth can be measured by SEM (Scanning Electron Microscopy) and EDS (Energy Dispersive X-ray Spectroscopy) analysis.

[0011] In some embodiments, T ≤ 13 μm may be used in Equation 1.

[0012] In some embodiments, the first piping may include at least one selected from the group consisting of carbon steel, low-alloy steel, stainless steel, and nickel-based alloys.

[0013] In some embodiments, the ammonia supply system further includes a connecting section that connects the first pipe and the second pipe, and the first hydrogen supply line can be connected to at least one of the first pipe and the second pipe, or to the connecting section.

[0014] In some embodiments, the first hydrogen supply line is connected to the second piping or the connecting portion, and the hydrogen gas stream flowing from the first hydrogen supply line into the second piping may contain hydrogen at a concentration of 50% by volume or more.

[0015] In some embodiments, the ammonia supply unit and the first piping are connected, and the ammonia gas stream flowing from the ammonia supply unit into the first piping may contain ammonia at a concentration of 99% to 100% by volume, based on the total volume of the ammonia gas stream.

[0016] In some embodiments, the ratio of the flow rate of the ammonia gas stream in the first piping to the flow rate of the hydrogen gas stream in the first hydrogen supply line may be 1:0.02 to 1:0.5.

[0017] In some embodiments, the temperature difference between the ammonia gas stream in the first piping and the hydrogen gas stream in the first hydrogen supply line may be between 0°C and 400°C.

[0018] In some embodiments, an ammonia gas stream flows from the first pipe into the second pipe, and the ammonia gas stream and the hydrogen gas stream are mixed in the second pipe to form a mixed gas stream, and the average volume ratio of ammonia (NH3) and hydrogen (H2) contained in the mixed gas stream may be 70:30 to 98:2.

[0019] In some embodiments, the first hydrogen supply line is connected to the second piping, and the temperature in the second piping from the connection point where the first hydrogen supply line is connected to the rear end can be controlled to more than 410°C to 800°C.

[0020] In some embodiments, when the entire length of the first pipe is divided into 100 equal parts and numbered from the front end to the rear end as the first region to the 100th region, the first hydrogen supply line can be connected to the first pipe between the 51st region and the 100th region.

[0021] In some embodiments, one or more second hydrogen supply lines that branch from at least one of the first hydrogen supply lines to supply a hydrogen gas stream can be included.

[0022] In some embodiments, one or more third hydrogen supply lines that branch from the second hydrogen supply lines to supply a hydrogen gas stream can be included.

[0023] In some embodiments, the hydrogen supply unit includes an external hydrogen supply unit and an internal hydrogen supply unit. The first hydrogen supply line is connected to the external hydrogen supply unit to form a non-circulating line, and the second hydrogen supply line can be connected to the internal hydrogen supply source to form a circulating line together with the first hydrogen supply line.

[0024] In some embodiments, the second hydrogen supply line may be a return line that supplies the hydrogen gas stream recovered from the ammonia demand unit back to the first hydrogen supply line.

[0025] The hydrogen production system according to an embodiment of the present disclosure includes the aforementioned ammonia supply system, and the ammonia demand unit can include an ammonia decomposition unit and a hydrogen collection unit.

[0026] The carbon-free power generation system according to an embodiment of the present disclosure includes the aforementioned ammonia supply system, and the ammonia demand unit can include an ammonia combustion unit and a turbine power generation unit.

[0027] The fuel cell system according to an embodiment of the present disclosure includes the aforementioned ammonia supply system, and the ammonia demand unit can include a fuel cell unit including one or more fuel cell stacks. [Effects of the Invention]

[0028] The ammonia supply system according to the embodiments of this disclosure can suppress or reduce corrosion caused by ammonia.

[0029] The hydrogen production system according to the embodiments of this disclosure can have improved reaction reliability and energy efficiency.

[0030] The carbon-free power generation system according to the embodiments of this disclosure can have improved reaction reliability and energy efficiency.

[0031] The fuel cell system according to the embodiments of this disclosure can have improved reaction reliability and energy efficiency.

[0032] Increased corrosion on the internal surfaces of piping or other components within an ammonia supply system can lead to reduced hydrogen production efficiency or uneven flow rates and purity of the hydrogen produced.

[0033] However, in the ammonia supply system according to the embodiments of this disclosure, the structural stability of equipment such as piping is maintained, thereby ensuring the efficiency and / or reproducibility of the hydrogen production reaction, and as a result, a more stable supply of hydrogen of uniform quality can be achieved. Furthermore, according to the ammonia supply system according to the embodiments of this disclosure, combustion reactions and electrochemical reactions (e.g., carbon-free power generation or fuel cell reactions) using hydrogen as fuel are carried out stably even during long-term operation, thereby reducing the degradation of the overall system performance and the non-uniformity of output. [Brief explanation of the drawing]

[0034] [Figure 1] Figure 1 is a schematic block diagram of an ammonia supply system according to one embodiment of the present disclosure. [Figure 2] Figure 2 is a schematic block diagram of a carbon-free power generation system according to one embodiment of the present disclosure. [Figure 3]Figure 3 is a schematic block diagram of a fuel cell system according to one embodiment of the present disclosure. [Figure 4] Figure 4 is a graph showing the evaluation results of corrosion resistance based on operating temperature when the operating time of the first chamber in Example 1, Example 1-1, and Example 1-2 is set to 36 hours. [Figure 5] Figure 5 is a graph showing the evaluation results of corrosion resistance based on operating temperature, assuming an operating time of 100 hours for the first chamber in Examples 1, 1-1, and 1-2. [Figure 6] Figure 6 shows SEM (Scanning Electron Microscopy) images of the cross-sections of nitrided test specimens after evaluating the corrosion resistance based on the operating time of the first chamber in Examples 1 to 5. [Figure 7] Figures 7a and 7b are SEM (Scanning Electron Microscopy) images of the cross-sections of nitrided test specimens after evaluating the corrosion resistance based on the operating time of the second chamber in Examples 1-5 and Comparative Examples 1-4. [Figure 8] Figure 8 is a graph showing the evaluation results of the corrosion rate for the first chamber in Examples 1 to 5. [Figure 9] Figure 9 is a graph showing the evaluation results of the corrosion rate for the second chamber in Example 1 and Comparative Examples 2 and 3. [Modes for carrying out the invention]

[0035] Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the drawings, so as to be easily implemented by a person ordinary skill in the art to which the present invention pertains. The drawings include exemplary block diagrams for a clearer illustration of the principles of the present invention and should not be construed as limiting the technical scope of the present disclosure. Furthermore, a person ordinary skill will understand that various modifications, substitutions, or additions are possible within the technical idea and scope of the present disclosure.

[0036] <Ammonia supply system> Figure 1 is a schematic block diagram of an ammonia supply system according to one embodiment of the present disclosure.

[0037] An ammonia supply system 100 according to an embodiment of the present disclosure may include one or more ammonia supply units 10A, 10B, 10C (hereinafter referred to as "10"), ammonia demand units 70A, 70B, 70C (hereinafter referred to as "70"), connecting lines 20A, 20B, 20C (hereinafter referred to as "20") that connect the ammonia supply unit 10 and the ammonia demand unit 70, a hydrogen supply unit, and first hydrogen supply lines 30A, 30B, 30C (hereinafter referred to as "30") that connect the hydrogen supply unit and the connecting line 20 and supply a hydrogen gas stream.

[0038] The connecting line 20 may include first pipes 21A, 21B, 21C (hereinafter referred to as "21") controlled to an average temperature of 410°C or less, and second pipes 22A, 22B, 22C (hereinafter referred to as "22") controlled to an average temperature of over 410°C.

[0039] For example, the ammonia supply system 100 may include an ammonia supply unit 10, an ammonia demand unit 70, a connecting line 20 arranged to connect the ammonia supply unit 10 and the ammonia demand unit 70, a hydrogen supply unit, and one or more first hydrogen supply lines 30 arranged to connect the hydrogen supply unit and the connecting line 20 and configured to supply a hydrogen gas stream, wherein the connecting line 20 may include a first pipe 21 configured to have an average temperature of 410°C or less, or 250°C to 410°C, or 300°C to 410°C, and a second pipe 22 configured to have an average temperature of 450°C to 800°C, or 500°C to 800°C, or 500°C to 750°C.

[0040] The second pipe 22 is made of a nickel-based alloy (N) that satisfies the following formula 1. T ) can include:

[0041] [Formula 1] T ≤ 15 μm

[0042] In the above formula 1, T is the nickel alloy (N T A cylindrical specimen with a cross-sectional diameter of 2 mm and a height of 200 mm is prepared. When the cylindrical specimen is exposed to a gas stream containing 97.2 volume% NH3, 2.1 volume% H2, and 0.7 volume% N2, and a temperature environment of 500°C for 100 hours, the maximum depth of nitrided material is obtained from the side of the cylindrical specimen in the direction of the central axis. This depth can be measured by SEM (Scanning Electron Microscopy) and EDS (Energy Dispersive X-ray Spectroscopy) analysis.

[0043] As a result, the ammonia supply system 100 can suppress or reduce corrosion in the devices, equipment, and piping during the process of supplying ammonia.

[0044] In this specification, the term "nickel-based alloy" can be used to encompass all alloys in which nickel is the main component and one or more metallic elements such as chromium (Cr), iron (Fe), molybdenum (Mo), cobalt (Co), aluminum (Al), titanium (Ti), and tungsten (W) are added.

[0045] Furthermore, in this specification, an alloy satisfying formula 1 is referred to as "nickel alloy (N)" to distinguish it from the aforementioned nickel-based alloy. T ) is referred to as ").

[0046] In the case of high-purity ammonia, there is a problem in that corrosion increases rapidly at high temperatures exceeding 410°C. When transporting ammonia at the aforementioned high temperatures, the piping, for example, the inside or the entirety of the piping, is made of the nickel-based alloy (N T By forming it in this way, nitriding can be effectively prevented.

[0047] For example, when a metal is exposed to an environment with high temperature and high-purity ammonia, the ammonia may react with the metal to cause a nitriding reaction. This nitriding reaction can cause a nitride product to form in the inner region from the surface of the metal.

[0048] For example, T, represented by equation 1, can be measured as follows.

[0049] The aforementioned nickel alloy (N T This substance does not significantly accelerate the nitriding reaction even at temperatures exceeding 410°C, and can suppress or reduce the formation of nitride products.

[0050] For example, the nickel-based alloy (N T When a cylindrical specimen of ) is exposed to a gas stream containing 97.2 volume% NH3, 2.1 volume% H2, and 0.7 volume% N2, and a temperature environment of 500°C for 100 hours, a nitrided cylindrical specimen can be obtained.

[0051] As used herein, the term "nitrided layer or nitrided portion" refers to a region in which nitrogen has diffused into the metal to form a metal nitride (MxNy) structure, which can be experimentally confirmed, for example, by XRD analysis or SEM-EDS. In the said region, the metal nitride phase may be detected by X-ray diffraction (XRD) analysis at a 2θ value corresponding to MxNy, such as Fe4N, CrN, or other metal nitride phases, depending on the substrate metal. On the other hand, the term "non-nitrided layer or non-nitrided portion" refers to a region of the metal substrate in which such a nitride phase is not observed under the same analytical conditions.

[0052] For example, 41 specimens can be obtained by cutting a nitrided cylindrical specimen at 5 mm intervals along its height from one end, perpendicular to the height. Scanning electron microscope (SEM) images can be taken of the circular cross-sections of the obtained specimens. The elemental composition of the SEM images can be analyzed using the energy-dispersive X-ray spectroscopy (EDS) function of the scanning electron microscope (SEM).

[0053] As a non-limiting example, a focused ion beam-scanning electron microscope (FIB-SEM) can be used as the scanning electron microscope. For example, a plasma focused ion beam-scanning electron microscope (FIB-SEM) manufactured by Thermo Fisher Scientific can be used.

[0054] In other words, in unnitrided metals, nitrides are either absent or undetectable. The elemental composition in a SEM image can be analyzed using the energy-dispersive X-ray spectroscopy (EDS) function of a scanning electron microscope (SEM), which allows for the identification of nitrides.

[0055] Nitriding depth refers to how deeply nitrogen penetrates the metal surface during the ammonia treatment process, and is used here as a measure related to corrosion resistance.

[0056] Based on the analysis results of the elemental composition, the nitrided depth can be measured from any three points on the outermost frame of the circular cross-section in the direction of the central axis. The "nitrided depth" may refer to the depth in the direction perpendicular to the side surface of the cylindrical test piece, that is, the depth in the direction extending along the central axis.

[0057] The smaller the maximum value of the aforementioned nitrided depth, the higher the corrosion resistance can be evaluated.

[0058] Each of the aforementioned average temperatures can be calculated, for example, as the arithmetic mean temperature of the inlet and outlet temperatures of each pipe, or as the mass flow rate average temperature or spatial average temperature within each pipe. The average temperature can be selected in an appropriate manner depending on the flow conditions, measurement environment, and system configuration, and may include an error range of ±10°C or ±1°C depending on the measurement conditions and environment.

[0059] In some embodiments, the temperature of the entire first pipe 21 can be controlled to 410°C or less, while the temperature of the entire second pipe 22 can be controlled to exceed 410°C.

[0060] In some embodiments, in Formula 1, T may be ≤ 13 μm, for example, T may be ≤ 12 μm. Thereby, it is possible to reduce the consumption of ammonia due to the generation of by-products in the ammonia supply process and prevent the performance degradation of devices and the like for a long period of time.

[0061] In some embodiments, the nickel-based alloy (N T ) can contain 40 wt% to 80 wt% of nickel. The content of the nickel is based on the total weight of the nickel-based alloy (N T ).

[0062] In some embodiments, the content of nickel contained in the nickel-based alloy (N T ) may be, for example, 40 wt% to 78 wt%, 50 wt% to 75 wt%, 52 wt% to 75 wt%, or 55 wt% to 70 wt%.

[0063] In some embodiments, the nickel-based alloy (N T ) can contain, for example, Ni-Cu-Fe-based alloys, Ni-Cr-Mo-W-based alloys, Ni-Cr-Fe-Mo-based alloys, and / or Ni-Cr-Co-W-based alloys.

[0064] The nickel-based alloy (N T ) can contain, for example, one or more alloys classified into any one selected from the group consisting of UNS (Unified Numbering System) N06601, UNS N06625, UNS N06690, UNS N07718, UNS N07792, and UNS N06002. Thereby, the ammonia supply system 100 can realize improved reaction reliability and energy efficiency by effectively preventing or suppressing corrosion in the connection line 20.

[0065] In some embodiments, the first piping 21 may include at least one selected from the group consisting of carbon steel, low-alloy steel, stainless steel, and nickel-based alloys.

[0066] The low-alloy steel may, for example, contain alloying elements in amounts of 1% to 35% by weight, 1% to 30% by weight, or 5% to 35% by weight, based on the total weight. For example, the alloying elements may include carbon, silicon, manganese, nickel, aluminum, chromium, phosphorus, sulfur, molybdenum, copper, and / or nitrogen. The stainless steel may, for example, include austenitic stainless steel, ferritic stainless steel, and / or martensitic stainless steel.

[0067] This makes it possible to suppress or reduce damage to the first pipe 21, prevent leakage of toxic ammonia, and achieve cost reductions.

[0068] In some embodiments, the interior or entirety of the second pipe 22 is made of a nickel-based alloy (N) satisfying formula 1. T This can be configured as follows. As a result, the thermal conductivity of the second pipe 22 does not easily decrease even after repeated use, and improved operational stability and energy efficiency can be achieved.

[0069] In some embodiments, the first hydrogen supply line 30 further includes a connecting section that connects the first pipe 21 and the second pipe 22, and the first hydrogen supply line 30 can be connected to at least one of the first pipe 21 and the second pipe 22, or to the connecting section.

[0070] As a non-limiting example, the connecting portion may include a connecting member, which may include a connector, flange, fitting, valve, etc.

[0071] In some embodiments, the first hydrogen supply line 30 may be connected to, for example, the first piping 21.

[0072] In some embodiments, the first hydrogen supply line 30 may be connected to the second piping 22.

[0073] In some embodiments, the first hydrogen supply line 30 may be connected to the first pipe 21 and the second pipe 22, respectively.

[0074] In some embodiments, the first hydrogen supply line 30 may be connected to the connecting portion together with the first pipe 21 and the second pipe 22 by a connector, and the connector may be a T-shaped connector.

[0075] In some embodiments, when the entire length of the first piping 21 is divided into 100 equal parts and numbered from the front end to the rear end as regions 1 to 100, the first hydrogen supply line 30 may be connected to the first piping 21 between regions 51 to 100.

[0076] In some embodiments, when the total length of the second pipe 22 is divided into 100 equal parts and numbered from the front end to the rear end as regions 1 to 100, the first hydrogen supply line 30 may be connected to the second pipe 22 between regions 1 to 80, for example, between regions 1 to 50, or between regions 1 to 40.

[0077] In some embodiments, the first hydrogen supply line 30 is connected to the second piping 22 or the connecting section, and the hydrogen gas stream flowing from the first hydrogen supply line 30 to the second piping 22 may contain 50% by volume of hydrogen or more, for example, 50% to 100% by volume, or 70% to 100% by volume. This can reduce the volume, cost, and power consumption of the required equipment.

[0078] In some embodiments, the ammonia supply unit 10 and the first piping 21 are connected, and the ammonia gas stream flowing from the ammonia supply unit 10 into the first piping 21 can contain 99% to 100% by volume, for example, 99.9% to 100% by volume. This improves the supply efficiency of the ammonia supply system 100, effectively reduces the overall volume of the device, saves energy required during operation, and stably achieves excellent ammonia decomposition efficiency. In some embodiments, the ratio of the flow rate of the ammonia gas stream in the first piping 21 to the flow rate of the hydrogen gas stream in the first hydrogen supply line 30 may be 1:0.02 to 1:0.5, for example, 1:0.05 to 1:0.30, 1:0.05 to 1:0.25, or 1:0.05 to 1:0.16. This allows for a more effective reduction in the corrosion rate due to nitriding in the overall internal region of the connecting line 20.

[0079] In some embodiments, the temperature difference between the ammonia gas stream in the first piping 21 and the hydrogen gas stream in the first hydrogen supply line 30 may be between 0°C and 400°C, for example, between 0°C and 300°C, 0°C and 200°C, 0°C and 250°C, or 0°C and 100°C. This allows for easy control of temperature changes (increases and decreases) in the ammonia gas stream throughout the interior of the connecting line 20.

[0080] In some embodiments, an ammonia gas stream flows from the first pipe 21 to the second pipe 22, where the ammonia gas stream and the hydrogen gas stream mix to form a mixed gas stream. The average volume ratio of ammonia (NH3) and hydrogen (H2) in the mixed gas stream may be 70:30 to 98:2. This can suppress or reduce the formation of nitriding products in the second pipe 22.

[0081] In some embodiments, the first hydrogen supply line 30 is connected to the second piping 22, and the temperature from the connection point between the second piping 22 and the first hydrogen supply line 30 to the rear end can be controlled to over 410°C and 800°C. This can further prevent corrosion of the second piping 22.

[0082] In some embodiments, the system may include one or more second hydrogen supply lines 50A, 50B, 50C (hereinafter referred to as "50") that branch off from at least one of the first hydrogen supply lines 30 and supply a hydrogen gas stream.

[0083] In some embodiments, the system may include one or more third hydrogen supply lines 60A, 61A, 62A, 63A, 60C (hereinafter referred to as "60") that branch off from the second hydrogen supply line 50 and supply a hydrogen gas stream.

[0084] The hydrogen gas streams supplied through the first to third hydrogen supply lines can be referred to as the first to third hydrogen gas streams, respectively.

[0085] In some embodiments, the hydrogen supply unit may include external hydrogen supply units 40A, 40B, and 40C, and an internal hydrogen supply unit.

[0086] As a non-limiting example, the external hydrogen supply unit may include high-pressure containers such as bombs, tanks, pipelines, etc., in which hydrogen (H2) is stored.

[0087] In some embodiments, the first hydrogen supply line 30 can be connected to the external hydrogen supply unit 40 to form a non-circulating line.

[0088] In some embodiments, the internal hydrogen supply unit may include a second hydrogen supply line 50, or a second hydrogen supply line 50 and a third hydrogen supply line 60. For example, the second hydrogen supply line 50 may be connected to the first hydrogen supply line 30 to form a circulation line together. For example, the third hydrogen supply line 60, the second hydrogen supply line 50, and the first hydrogen supply line 30 may be connected in sequence to form a circulation line together.

[0089] In some embodiments, the second hydrogen supply line 50, or the second hydrogen supply line 50 and the third hydrogen supply line 60, may be return lines that supply the hydrogen gas stream recovered from the ammonia demand unit 70 back to the first hydrogen supply line 30.

[0090] For example, the first hydrogen supply line 30 connected to the external hydrogen supply unit can independently supply a hydrogen gas stream in one direction.

[0091] For example, the second hydrogen supply line 50 can resupply the hydrogen gas stream recovered from the ammonia demand unit 70 to the first hydrogen supply line 30, and the supplied hydrogen gas stream can flow into the second piping 22 and be circulated.

[0092] For example, the third hydrogen supply line 60 can supply the hydrogen gas stream recovered from the ammonia demand unit 70 to the second hydrogen supply line 50, the second hydrogen supply line 50 can resupply the hydrogen gas stream back to the first hydrogen supply line 30, and the supplied hydrogen gas stream can flow into the second piping 22 and be circulated.

[0093] Referring to Figure 1, if the ammonia supply system 100 includes both a non-circulating line and a circulating line, the ammonia supply system 100 may include two or more first hydrogen supply lines 30-1, 30-2 connected to the external hydrogen supply unit 40 and the second hydrogen supply line 50, respectively, or it may include one or more first hydrogen supply lines 30-1 connected to one end of the external hydrogen supply unit 40 and connected between both ends of the second hydrogen supply line 50, or it may include both of these (30-1 and 30-2).

[0094] A first hydrogen supply line 30-1, to which an external hydrogen supply unit 40 is connected at one end and a second hydrogen supply line 50 is connected between its ends, may include a first sub-line 30-1a connected from the external hydrogen supply unit 40 to the point where the second hydrogen supply line 50 is connected, and a second sub-line 30-1b connected from the point where the second hydrogen supply line 50 is connected to the opposite end of the first hydrogen supply line 30-1. From the point where the second hydrogen supply line 50 is connected to the first hydrogen supply line 30-1, the hydrogen gas stream supplied from the external hydrogen supply unit 40 and the hydrogen gas stream supplied from the second hydrogen supply line 50 may be mixed and supplied as a single stream to the opposite end. For the point where the second hydrogen supply line 50 is connected, refer to the description of the connection point in this specification.

[0095] In some embodiments, the ammonia supply system 100 may further include a monitoring unit, which may include a temperature sensor, a flow rate sensor, and the like. The monitoring unit may include, for example, a controller that detects temperature and flow rate and controls them within a set range based on the detected values, and may further include a pressure sensor, a gas composition analyzer, a leak detection sensor, or an alarm unit.

[0096] In some embodiments, the system may further include connecting members that connect each connecting line 20 and / or each pipe, etc. In non-limiting examples, the connecting members may include connectors, flanges, fittings, valves, etc.

[0097] As a non-limiting example, the first to third hydrogen supply lines 60 can each be formed by piping, tubes, or the like.

[0098] As a non-limiting example, the first to third hydrogen supply lines 60 may include at least one selected from carbon steel, low-alloy steel, and stainless steel.

[0099] In some embodiments, the ammonia supply unit 10 can store and supply ammonia. The ammonia supply unit 10 can store and supply, for example, ammonia in gaseous form (hereinafter sometimes abbreviated as "gas-phase ammonia") or ammonia in liquid form (hereinafter sometimes abbreviated as "liquid-phase ammonia").

[0100] When the ammonia supply unit 10 stores and supplies liquid-phase ammonia, for example, the ammonia supply unit 10 further includes a vaporization unit, and for example, liquid-phase ammonia can be supplied from an ammonia storage container to the vaporization unit, and gaseous ammonia vaporized from the vaporization unit by a vaporizer can be supplied to the connecting line 20.

[0101] As a non-limiting example, the ammonia supply unit 10 may include a high-pressure container such as a cylinder (bomb) or a tank in which ammonia (NH3) is stored.

[0102] The ammonia supply unit 10 may further include a preheating unit connected to the vaporization unit, and the ammonia in the preheating unit can be preheated by a preheater before being supplied to the connecting line 20.

[0103] In some embodiments, the ammonia demand unit 70 may include a hydrogen generator that converts ammonia into hydrogen, a combustion device that uses ammonia directly as fuel, or a fuel cell device that uses hydrogen derived from ammonia.

[0104] These devices can be used in a variety of applications within an ammonia supply system 100, such as generating energy, providing a heat source, generating power, or supplying reducing agents for chemical reactions.

[0105] The aforementioned connecting line 20 and / or the first to third hydrogen supply lines 60, etc., can be modified in various ways as needed.

[0106] As a non-limiting example, the ammonia supply unit 10, the ammonia demand unit 70, the hydrogen supply unit, the aforementioned connecting line 20 and / or the first to third hydrogen supply lines 60, etc., may each include one or more inlets and / or outlets through which a gas stream flows in or out, and may further include one or more communication valves that control them.

[0107] In a non-limiting embodiment, the ammonia supply system 100 may include a first temperature control device configured to maintain the average temperature of the first pipe 21 at 410°C or below, and a second temperature control device configured to maintain the average temperature of the second pipe 22 at 410°C or above. For example, the first and second temperature control devices may include heaters, thermocouples, and / or controllers. The heaters may be, for example, electric resistance heaters, induction heaters, or heating means operating using an external heat source. The thermocouples may be able to detect the internal temperatures of the first pipe 21 and the second pipe 22 in real time, and the controllers may be able to control the operation of the heaters based on the detected temperature information so that the temperature is maintained within a predetermined range. The configuration and installation method of the temperature control devices are not particularly limited.

[0108] <Hydrogen Production System> The hydrogen production system according to the embodiments of the present disclosure includes the ammonia supply system 100 described above, and the ammonia demand unit 70 may include an ammonia decomposition unit 71A and a hydrogen collection unit 72A.

[0109] For example, if the ammonia demand unit 70 includes an ammonia decomposition unit 71A and a hydrogen collection unit 72A, the ammonia supply system 100 can be provided as a hydrogen production system.

[0110] In some embodiments, the hydrogen production system may include, for example, a vaporization and / or preheating unit included in the ammonia supply unit 10, an ammonia decomposition chamber and hydrogen collection unit 72A included in the ammonia decomposition unit 71A, and may further include a heat supply unit including a hydrogen purification unit 73A, a hydrogen storage unit 74A, an ammonia collection unit and / or a combustor, which may be connected to each other via sublines.

[0111] Each of the aforementioned sub-lines can be formed using pipes, tubes, or the like.

[0112] As a non-limiting example, the subline may include at least one selected from carbon steel, low-alloy steel, and stainless steel.

[0113] The arrangement and length of the aforementioned sub-lines can be changed in various ways as needed.

[0114] In some embodiments, the ammonia demand unit 70 may include an ammonia decomposition unit 71A, a hydrogen collection unit 72A, and a hydrogen purification unit 73A.

[0115] The hydrogen collection section 72A may include a device for collecting and separating hydrogen gas produced by the ammonia decomposition reaction, such as a gas-solid separator, adsorption tower, absorption tower, TSA (Temperature Swing Adsorption) device, scrubber, condenser, membrane separator, etc.

[0116] The hydrogen purification section 73A may include equipment to remove impurities (e.g., nitrogen, unreacted ammonia, water, etc.) from the collected hydrogen gas to obtain high-purity hydrogen, and may include, for example, a PSA (Pressure Swing Adsorption) device, a VPSA (Vacuum Pressure Swing Adsorption) device, a membrane separator, a purifier, etc.

[0117] For example, the aforementioned gases can be separated and / or collected using temperature swing adsorption (TSA), pressure swing adsorption (PSA), or vacuum pressure swing adsorption (VPSA) methods.

[0118] The hydrogen collection section 72A and / or the hydrogen purification section 73A may contain an adsorbent, which may include, for example, CaCl2 / Al2O3, MgCl2 / Al2O3, silica, alumina, activated carbon, and / or zeolite. The structure of the zeolite may be, for example, in the form of MFI, CHA, CHA-Cs, CHI, ERI, FAU, FER, GOO, HEU, LTA, MER, MON, MOR, RHO, AEI, AFX, DDR, LEV, RTH, etc.

[0119] In some embodiments, the structure of the zeolite may be, for example, in the form of CHA, LTA, and / or FAU.

[0120] The hydrogen collection section 72A may include an adsorption tower filled with an adsorbent. The adsorption tower may be, for example, one or more adsorption towers connected together, one adsorption tower with one or more towers connected together, or a combination thereof.

[0121] In some embodiments, the hydrogen gas stream recovered from the ammonia decomposition unit 71A, the hydrogen collection unit 72A, and / or the hydrogen purification unit 73A can be supplied to the first hydrogen supply line 30 via a second hydrogen supply line 50 and / or a third hydrogen supply line 60. The second hydrogen supply line 50 and / or the third hydrogen supply line 60 can be provided as a circulation line or a return line.

[0122] For example, a sub-line can be connected between the ammonia decomposition unit 71A and the hydrogen collection unit 72A, a sub-line can be connected between the hydrogen collection unit 72A and the hydrogen purification unit 73A, and / or the hydrogen purification unit 73A can be connected to the third hydrogen supply line 60, the third hydrogen supply line 60 can be connected to the second hydrogen supply line 50, and the second hydrogen supply line 50 can be connected to the first hydrogen supply line 30.

[0123] The hydrogen gas stream contains hydrogen (H2) and may further contain, for example, ammonia (NH3) and / or water (H2O).

[0124] In some embodiments, the ammonia decomposition section 71A may include an ammonia decomposition reactor, and the ammonia decomposition reactor may include a catalyst section filled with a catalyst.

[0125] In some embodiments, the hydrogen gas stream recovered after ammonia decomposition in the ammonia demand unit 70 can be supplied to the second hydrogen supply line 50 and / or the third hydrogen supply line 60.

[0126] In some embodiments, after ammonia is separated, the recovered hydrogen gas stream can be supplied to the second hydrogen supply line 50 and / or the third hydrogen supply line 60.

[0127] In some embodiments, the hydrogen gas stream recovered unpurified after hydrogen purification can be supplied to the second hydrogen supply line 50 and / or the third hydrogen supply line 60. Here, the composition of the hydrogen gas stream may include, for example, 10 to 30 volume percent hydrogen.

[0128] For example, the composition of the hydrogen gas stream supplied from the subline connecting the ammonia decomposition unit 71A and the hydrogen collection unit 72A to the second hydrogen supply line 50 and / or the third hydrogen supply line 60 may be the same as the composition of the gas stream flowing from the ammonia decomposition unit 71A to the gas inlet of the hydrogen collection unit 72A.

[0129] For example, the composition of the hydrogen gas stream supplied from the sub-line connecting the hydrogen collection unit 72A and the hydrogen purification unit 73A to the second hydrogen supply line 50 and / or the third hydrogen supply line 60 may be the same as the composition of the gas stream flowing from the hydrogen collection unit 72A to the gas inlet of the hydrogen purification unit 73A.

[0130] The aforementioned hydrogen gas stream can also contain nitrogen, water vapor, and other elements.

[0131] In some embodiments, the hydrogen production system may further include a hydrogen storage unit 74A.

[0132] The hydrogen storage unit 74A can store hydrogen separated from, for example, the hydrogen collection unit 72A and the hydrogen purification unit 73A.

[0133] As a non-limiting example, the hydrogen storage unit 74A may be a hydrogen storage tank.

[0134] In some embodiments, the purity of the hydrogen produced by the hydrogen production system and stored in the hydrogen storage unit 74A may be 99% by volume or higher, for example, 99.9% by volume or higher.

[0135] In some embodiments, the production rate of hydrogen stored in the hydrogen storage unit 74A is 1,300 Nm³. 3 It may be greater than or equal to / h, for example, 1,300 Nm 3 / h~800,000Nm 3 / h is also acceptable.

[0136] <Carbon-free power generation system> Figure 2 is a schematic block diagram of a carbon-free power generation system according to one embodiment of the present disclosure.

[0137] The carbon-free power generation system 200 according to the embodiments of the present disclosure includes the ammonia supply system 100 described above, and the ammonia demand unit 70 may include an ammonia combustion unit 71B and a turbine power generation unit 72B. This makes it possible to stably generate electrical energy without reducing long-term reaction reliability and energy efficiency.

[0138] The turbine power generation unit may include a gas turbine generator.

[0139] As a non-limiting example, a gas turbine generator may include a gas turbine that converts thermal energy generated by the combustion of fuel into rotational energy, and a generator that generates electricity using the rotational energy of the gas turbine.

[0140] The aforementioned gas turbine generator can produce electricity by driving a turbine through the combustion of fuel, and in this process, it can achieve carbon-free power generation without emitting carbon dioxide (CO2).

[0141] In the aforementioned gas turbine generator, waste heat can be generated through various paths in the form of combustion gas, exhaust gas, etc.

[0142] In some embodiments, the carbon-free power generation system may further include a waste heat recovery and supply unit that recovers waste heat generated in the gas turbine power generation unit and supplies the heat to a connecting line 20 or the like. In non-limiting examples, the waste heat recovery unit may include a heat exchanger, a waste heat recovery boiler (WHRB), a condensate tube type heat recovery unit, or an organic Rankine cycle (ORC) system.

[0143] In some embodiments, the carbon-free power generation system may further include an exhaust gas processing unit 73B. The exhaust gas processing unit can process exhaust gas generated in, for example, a gas turbine power generation unit or combustion unit by methods such as cooling, filtering, neutralizing, or adsorption.

[0144] As a non-limiting example, the exhaust gas processing unit may include a scrubber, a selective catalytic reduction (SCR), an oxidation catalyst, or an activated carbon adsorption device.

[0145] In some embodiments, the carbon-free power generation system may further include waste heat control valves, exhaust gas regulators, and / or intermediate heat storage units for improving heat exchange efficiency or controlling operating conditions.

[0146] <Fuel cell system> Figure 3 is a schematic block diagram of a fuel cell system according to one embodiment of the present disclosure.

[0147] The fuel cell system 300 according to the embodiments of this disclosure includes the ammonia supply system 100 described above, and the ammonia demand unit 70 may include a fuel cell unit 71C that includes one or more fuel cell stacks. This makes it possible to generate electrical energy without reducing long-term reaction reliability and energy efficiency.

[0148] In some embodiments, the fuel cell system may be a solid oxide fuel cell (SOFC) system.

[0149] As a non-limiting example, the solid oxide fuel cell unit may further include a fuel supply unit connected to a fuel supply pipe, a fuel storage unit connected to the fuel supply unit, a fuel cell unit connected to the fuel storage unit that receives fuel and generates electrical energy, a heat supply unit, a waste heat recovery unit, and / or a refrigerant circulation channel.

[0150] For example, the fuel cell stack may include a cathode and an anode, and a solid electrolyte may be included between them. The solid electrolyte may include, for example, a solid oxide that can permeate oxygen or hydrogen ions.

[0151] As a non-limiting example, the cathode may be connected to an air supply unit and receive pressurized and heated air supplied from an external source.

[0152] As a non-limiting example, the anode may be connected to the fuel supply unit and receive a supply of fuel such as hydrogen or hydrogen-containing gas from the fuel supply unit.

[0153] In some embodiments, the fuel cell system may further include the ammonia decomposition unit described above, and may further include the hydrogen collection unit together with the ammonia decomposition unit. This allows for the effective supply of hydrogen and / or hydrogen-containing gas to the fuel supply unit.

[0154] In some embodiments, a second hydrogen supply line 50 and / or a third hydrogen supply line 60 can be connected to the fuel cell unit. After the fuel cell unit produces electricity, the hydrogen gas stream contained in the unreacted feed can be supplied to the circulation line including the second hydrogen supply line 50 and / or the third hydrogen supply line 60.

[0155] In some embodiments, the fuel cell system may further include an exhaust gas processing unit 72C. The exhaust gas processing unit can be described in the preceding text.

[0156] The embodiments of this disclosure will be further described below with reference to specific experimental examples. The examples and comparative examples included in the experimental examples are illustrative of this disclosure and do not limit the scope of the attached claims.

[0157] Example 1 An ammonia supply system was designed, comprising an ammonia storage tank made of SUS304 material; a first pipe made of SUS304 material connected to the ammonia storage tank; a second pipe made of Inconel625 material connected to the first pipe; and a hydrogen generator connected to the second pipe. In the ammonia supply system, the first pipe and the second pipe are connected using a T-shaped connector, and a first hydrogen supply line is connected to the connector, and the first hydrogen supply line is connected to a cylinder (bomb) in which hydrogen (H2) is stored. Furthermore, the hydrogen generator and the first hydrogen supply line are connected via a second hydrogen supply line to form a circulation line. The ammonia supply system described above was implemented according to the conditions shown in Tables 1 and 2 below. In this case, the operating temperature may refer to the average temperature.

[0158] Example 2 Except for the second pipe being made of Inconel 601 material, the same system as in Example 1 was implemented according to the conditions in Tables 1 and 2 below.

[0159] Example 3 Except for the first pipe being made of carbon steel, the same system as in Example 1 was implemented according to the conditions in Tables 1 and 2 below.

[0160] Example 4 A system similar to that in Example 1 was implemented according to the conditions in Tables 1 and 2 below.

[0161] Example 5 A system similar to that in Example 1 was implemented according to the conditions in Tables 1 and 2 below.

[0162] Comparative Example 1 A system similar to that in Example 1 was implemented according to the conditions in Tables 1 and 2 below, except that the first piping was excluded and the second piping was connected to the ammonia storage tank.

[0163] Comparative Example 2 Except for the second pipe being made of SUS304, the same system as in Example 1 was implemented according to the conditions in Tables 1 and 2 below.

[0164] Comparative Example 3 Except for the second pipe being made of SUS316, the same system as in Example 1 was implemented according to the conditions in Tables 1 and 2 below.

[0165] Comparative Example 4 Except for the second pipe being made of Inconel 601 material, the same system as in Comparative Example 1 was implemented according to the conditions in Tables 1 and 2 below.

[0166] [Table 1]

[0167] [Table 2]

[0168] Experimental example Experimental Example 1: Evaluation of Corrosion Resistance In the above-described examples and comparative examples, the corrosion resistance of the inner surfaces of the first and second pipes was evaluated using metal test specimens made of the same material as their inner surfaces (hereinafter referred to as "corresponding metal test specimens").

[0169] Under substantially identical atmospheric conditions, the nitriding reaction by ammonia occurring on the inner surfaces of the first and second pipes proceeds at substantially the same rate and using the same reaction equation on the corresponding metal test specimens, even considering the effects of test errors and differences in surface conditions.

[0170] Therefore, the evaluation results of corrosion resistance on corresponding metal test pieces were used as an index for evaluating the corrosion resistance on the internal surface of the piping.

[0171] (1) Corrosion resistance of the first piping at its operating temperature 1) In Example 1, a metal test piece made of the same material (SUS304) as the first pipe was prepared as a cylindrical shape with a circular cross-sectional diameter of 2 mm and a height of 200 mm (hereinafter referred to as "cylindrical test piece").

[0172] Furthermore, cylindrical test specimens made of SUS316 and Inconel625 were prepared using the same method, and these were designated as Example 1-1 and Example 1-2, respectively.

[0173] A gas stream supply section, a gas stream discharge section, and a vertical quartz tube reactor connected to a furnace were prepared.

[0174] Each cylindrical test specimen was placed in the vertical quartz tube reactor, and the internal temperature of the vertical quartz tube reactor was raised to the operating temperature at a heating rate of 10°C / min. At this time, a gas stream containing 99.99999 volume% NH3 was continuously supplied to the vertical quartz tube reactor.

[0175] The operating temperature of the vertical quartz tube reactor was increased by 10°C increments from 300°C to 450°C, and the vertical quartz tube reactor was operated at the operating temperature for 36 hours to obtain nitrided cylindrical test specimens.

[0176] Forty-one specimens were obtained by cutting a nitrided cylindrical specimen at 5 mm intervals along its height from one end, perpendicular to the height. Scanning electron microscope (SEM) images were taken of the circular cross-sections of the obtained specimens using a Thermo Fisher Scientific Helios PFIB instrument. The magnification conditions were selected to accurately measure the nitriding depth; for example, magnifications of 2000x and 500x were used depending on whether the nitriding depth was 40 μm or less or 40 μm or more.

[0177] The elemental composition within the aforementioned SEM images was analyzed using the energy-dispersive X-ray spectroscopy (EDS) function of the same SEM instrument. The specific analysis conditions were as follows. - Acceleration voltage: kV -Analysis mode: Point analysis (Point)? Area analysis (Map)? - Presence or absence of coating on the cross-section of the test specimen: - Analysis time:

[0178] Based on the elemental composition analysis, the nitridation depth was measured in the direction of the central axis from three arbitrary points on the outermost frame of the circular cross-section. We evaluated that the smaller the maximum depth of nitriding, the higher the corrosion resistance. The results are shown in Table 3 and Figure 4. Since it is not possible to show the nitriding depth at all temperatures in Table 3, the results are shown separately for 390°C, 410°C, and 430°C.

[0179] [Table 3]

[0180] 2) Cylindrical test specimens made of SUS304, SUS316, and Inconel625 were prepared using the same method as described above. For the cylindrical specimens, the maximum nitrided depth was evaluated using the same method as described above, except that the operating time of the vertical quartz tube reactor was changed to 100 hours. The results are shown in Table 4 and Figure 5.

[0181] [Table 4]

[0182] From Tables 3 and 4 and Figures 4 and 5 above, it was confirmed that corrosion of the internal surface of the first pipe begins to increase rapidly at temperatures above 410°C. Furthermore, as the operating time increased under conditions above 410°C, the corrosion rate of the internal surface of the first pipe accelerated even further.

[0183] (2) Corrosion resistance of the first piping based on operating time In Examples 1 to 5, a metal test piece made of the same material as the first pipe was prepared as a cylindrical shape with a circular cross-sectional diameter of 2 mm and a height of 200 mm (hereinafter referred to as "cylindrical test piece").

[0184] A gas stream supply section, a gas stream discharge section, and a vertical quartz tube reactor connected to a furnace were prepared.

[0185] A cylindrical test specimen was placed in the vertical quartz tube reactor, and the internal temperature of the vertical quartz tube reactor was increased at a heating rate of 10°C / min to the operating temperature of the first piping corresponding to Table 1.

[0186] Subsequently, the cylindrical test specimen was exposed to the environment corresponding to Table 1 for 100 hours from the time the operating temperature of the first piping was reached, thereby obtaining a nitrided cylindrical test specimen.

[0187] For the nitrided cylindrical specimens, the maximum nitrided depth was evaluated using the same method as described above. The results are shown in Table 5 and Figure 6.

[0188] (3) Corrosion resistance of the second piping based on operating time In Examples 1-5 and Comparative Examples 1-4, metal test specimens made of the same material as the second pipe were prepared in a cylindrical shape with a circular cross-section diameter of 2 mm and a height of 200 mm (hereinafter referred to as "cylindrical test specimens").

[0189] A gas stream supply section, a gas stream discharge section, and a vertical quartz tube reactor connected to a furnace were prepared.

[0190] A cylindrical test specimen was placed in the vertical quartz tube reactor, and the internal temperature of the vertical quartz tube reactor was increased at a heating rate of 10°C / min to the operating temperature of the second pipe corresponding to Table 2.

[0191] Subsequently, the cylindrical specimens were exposed to the environment corresponding to Table 2 for 100 hours from the point when the operating temperature of the second pipe was reached, thereby obtaining nitrided cylindrical specimens.

[0192] For the nitrided cylindrical specimens, the maximum nitrided depth was evaluated using the same method as described above. The results are shown in Table 5, Figures 7a and 7b. The SEM measurement conditions for Examples 1-5 and Comparative Example 1 are as follows. HV (High voltage): 15.00kV CURR (Beam Current): 1.6nA MAG (Magnification): 2000x DET(Detector): CBS(Circular Backscatter Detector) The SEM measurement conditions for Comparative Examples 2-4 are as follows: HV (High voltage): 15.00kV CURR (Beam Current): 1.6nA MAG (Magnification): 500x

[0193] [Table 5]

[0194] Referring to Table 5 above, in Example 3, where the first piping was made of carbon steel, the corrosion level during long-term operation was relatively high.

[0195] In contrast, nickel alloys (N) satisfy the aforementioned equation 1. T The second piping in the example, including the above, was evaluated as having a low level of corrosion even after long-term operation, demonstrating improved reliability and stability.

[0196] In Example 5, the hydrogen concentration in the gas stream supplied to the second piping was relatively low, resulting in reduced corrosion resistance compared to the other examples.

[0197] In Comparative Examples 1 and 4, a gas stream containing 99.99999 volume% ammonia was supplied directly to the high-temperature second pipe without passing through the first pipe, resulting in very rapid nitriding and degraded reliability and stability during long-term operation. In Comparative Example 4, the corrosion rate increased even more than in Comparative Example 1 because the second pipe was made of Inconel 601 material.

[0198] In Comparative Examples 2 and 3, the second piping was manufactured from SUS304 and SUS316 materials, respectively. However, since these materials do not satisfy the above formula 1, the corrosion resistance after long-term operation deteriorated further.

[0199] Experimental Example 2: Evaluation of Corrosion Rate (1) Corrosion rate of the first pipe In Examples 1 to 5, a metal test piece made of the same material as the first pipe was prepared as a cylindrical shape with a circular cross-sectional diameter of 2 mm and a height of 200 mm (hereinafter referred to as "cylindrical test piece").

[0200] A gas stream supply section, a gas stream discharge section, and a vertical quartz tube reactor connected to a furnace were prepared.

[0201] A cylindrical test specimen was placed in the vertical quartz tube reactor, and the internal temperature of the vertical quartz tube reactor was increased at a heating rate of 10°C / min to the temperature of the first pipe corresponding to Table 1.

[0202] Subsequently, cylindrical test specimens were exposed to the environmental conditions corresponding to Table 1 for 36 hours, 100 hours, 200 hours, and 400 hours, respectively, starting from the time the operating temperature of the first piping was reached, to obtain nitrided cylindrical test specimens.

[0203] For the nitrided cylindrical specimens, the maximum nitrided depth was evaluated using the same method as described above. The results are shown in Table 6 and Figure 8.

[0204] [Table 6]

[0205] According to Table 6 above, in Example 3, where carbon steel piping was used, the increase in corrosion rate was greater than in the other examples as the operating time increased at an operating temperature of 350±10℃.

[0206] (2) Corrosion rate of the second pipe In Example 1 and Comparative Examples 2 and 3, metal test specimens made of the same material as the second pipe were prepared in a cylindrical shape with a circular cross-section diameter of 2 mm and a height of 200 mm (hereinafter referred to as "cylindrical test specimens").

[0207] A vertical quartz tube reactor connected to the gas stream supply unit and furnace was prepared.

[0208] A cylindrical test specimen was placed in the vertical quartz tube reactor, and the temperature of the vertical quartz tube reactor was increased at a heating rate of 10°C / min to the operating temperature of the second piping corresponding to Table 2.

[0209] Subsequently, cylindrical specimens were exposed to the atmospheres corresponding to those shown in Table 2 for 36 hours, 100 hours, 200 hours, and 400 hours, starting from the time the operating temperature of the second piping was reached, to obtain nitrided cylindrical specimens.

[0210] For the nitrided cylindrical specimens, the maximum nitrided depth was evaluated using the same method as described above. The results are shown in Table 7 and Figure 9.

[0211] [Table 7]

[0212] Referring to Table 7 above, at an operating temperature of 510±10℃, a nickel-based alloy (N) that satisfies the aforementioned formula 1 is T The degree of nitriding to the second pipe in Example 1, including the above, was very low, and the increase in the maximum nitrided depth was small even after long-term operation, demonstrating improved reliability and safety.

[0213] In contrast, in the comparative example, since the second piping was made of SUS304 and SUS316 material, respectively, the corrosion resistance deteriorated at the operating temperature, and the rate of corrosion increased significantly as the operating time increased.

Claims

1. Ammonia supply unit; Ammonia demand section; A connecting line that connects the ammonia supply unit and the ammonia demand unit; Hydrogen supply unit; and It includes one or more first hydrogen supply lines that connect the hydrogen supply unit and the connecting line and supply a hydrogen gas stream, The connecting line includes a first pipe controlled to an average temperature of 410°C or less, and a second pipe controlled to an average temperature of over 410°C. The second pipe is made of a nickel-based alloy (N) that satisfies the following formula 1. Ｔ Ammonia supply systems, including: [Formula 1] T ≤ 15 μm (In formula 1 above, T is the nickel alloy (N Ｔ A cylindrical test specimen with a cross-sectional diameter of 2 mm and a height of 200 mm was prepared, and the cylindrical test specimen was subjected to 97.2 volume% NH ３ , 2.1 volume% H ２ , and 0.7 volume% N ２ This is the maximum depth of nitridation from the side of the cylindrical specimen in the direction of the central axis after exposure to a gas stream containing and a temperature environment of 500°C for 100 hours, and this depth is measured by SEM (Scanning Electron Microscopy) and EDS (Energy Dispersive X-ray Spectroscopy) analysis.

2. The ammonia supply system according to claim 1, wherein in the above formula 1, T ≤ 13 μm.

3. The ammonia supply system according to claim 1, wherein the first piping includes at least one selected from the group consisting of carbon steel, low-alloy steel, stainless steel, and nickel-based alloys.

4. It further includes a connecting portion that connects the first pipe and the second pipe, The ammonia supply system according to claim 1, wherein the first hydrogen supply line is connected to at least one of the first pipe and the second pipe, or to the connecting portion.

5. The ammonia supply system according to claim 4, wherein the first hydrogen supply line is connected to the second piping or the connecting portion, and the hydrogen gas stream flowing from the first hydrogen supply line into the second piping contains hydrogen in an amount of 50% by volume or more.

6. The ammonia supply unit and the first piping are connected, The ammonia supply system according to claim 4, wherein the ammonia gas stream flowing from the ammonia supply unit into the first piping contains ammonia at a concentration of 99% to 100% by volume, based on the total volume of the ammonia gas stream.

7. The ammonia supply system according to claim 6, wherein the ratio of the flow rate of the ammonia gas stream in the first piping to the flow rate of the hydrogen gas stream in the first hydrogen supply line is 1:0.02 to 1:0.

5.

8. The ammonia supply system according to claim 6, wherein the temperature difference between the ammonia gas stream in the first piping and the hydrogen gas stream in the first hydrogen supply line is 0°C to 400°C.

9. An ammonia gas stream flows from the first pipe to the second pipe. In the second piping, the ammonia gas stream and the hydrogen gas stream are mixed to form a mixed gas stream. Ammonia (NH) contained in the aforementioned mixed gas stream ３ ) and hydrogen (H ２ The ammonia supply system according to claim 6, wherein the average volume ratio of ) is 70:30 to 98:

2.

10. The first hydrogen supply line is connected to the second piping, The ammonia supply system according to claim 4, wherein the temperature in the second piping from the connection point to which the first hydrogen supply line is connected to the rear end is controlled to be greater than 410°C and 800°C.

11. The ammonia supply system according to claim 4, wherein when the total length of the first piping is divided into 100 equal parts and numbered from the front end to the rear end as regions 1 to 100, the first hydrogen supply line is connected to the first piping between regions 51 to 100.

12. The ammonia supply system according to claim 1, further comprising one or more second hydrogen supply lines that branch off from at least one of the first hydrogen supply lines and supply a hydrogen gas stream.

13. The ammonia supply system according to claim 12, further comprising one or more third hydrogen supply lines that branch off from the second hydrogen supply line and supply a hydrogen gas stream.

14. The hydrogen supply unit includes an external hydrogen supply unit and an internal hydrogen supply unit. The ammonia supply system according to claim 12, wherein the first hydrogen supply line is connected to the external hydrogen supply unit to form a non-circulating line, and the second hydrogen supply line is connected to the internal hydrogen supply source to form a circulating line together with the first hydrogen supply line.

15. The ammonia supply system according to claim 14, wherein the second hydrogen supply line is a return line that supplies the hydrogen gas stream recovered from the ammonia demand section back to the first hydrogen supply line.

16. The ammonia supply system includes the ammonia supply system described in claim 1, The ammonia demand unit is a hydrogen production system that includes an ammonia decomposition unit and a hydrogen collection unit.

17. The ammonia supply system includes the ammonia supply system described in claim 1, The ammonia demand unit is a carbon-free power generation system that includes an ammonia combustion unit and a turbine power generation unit.

18. The ammonia supply system includes the ammonia supply system described in claim 1, The ammonia demand unit includes a fuel cell unit which includes one or more fuel cell stacks, in a fuel cell system.

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