Corrosion control systems, carbon-free power generation systems, and fuel cell systems

Abstract

To provide corrosion suppression systems, carbon-free power generation systems, and fuel cell systems with improved reaction reliability and energy efficiency. [Solution] A corrosion suppression system, a carbon-free power generation system, and a fuel cell system are provided. The corrosion suppression system includes an ammonia supply unit, a first conduit connected to the ammonia supply unit, an ammonia decomposition unit including a chamber connected to the first conduit, and a second conduit connected to the chamber, wherein the operating temperature of the chamber is 410°C or lower, the first conduit and the chamber include at least one selected from the group consisting of carbon steel, low alloy steel, stainless steel, and nickel alloys, and the second conduit is a nickel alloy (N) satisfying the following formula 1. T (This can include) (Equation 1) T ≤ 15 μm

Description

[Technical Field]

[0001] The disclosures of this application relate to corrosion suppression systems, carbon-free power generation systems, and fuel cell systems. Embodiments of this disclosure also relate to methods for decomposing ammonia using corrosion suppression 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 project] [Problems that the invention aims to solve]

[0004] One objective of this disclosure is to provide a corrosion suppression system with improved reaction reliability and energy efficiency.

[0005] One of the objectives of this disclosure is to provide a carbon-free power generation system with improved reaction reliability and energy efficiency.

[0006] One objective of this disclosure is to provide a fuel cell system with improved reaction reliability and energy efficiency. [Means for solving the problem]

[0007] A corrosion suppression system according to an embodiment of the present disclosure includes an ammonia supply unit, a first conduit connected to the ammonia supply unit, an ammonia decomposition unit including a chamber connected to the first conduit, and a second conduit connected to the chamber, wherein a first gas stream containing ammonia flows into the chamber via the first conduit, the ammonia is partially decomposed in the chamber to produce hydrogen and nitrogen, and a second gas stream containing unreacted ammonia, hydrogen and nitrogen that was not decomposed in the chamber is discharged from the chamber, the operating temperature of the chamber is 410°C or lower, the first conduit and the chamber include at least one selected from the group consisting of carbon steel, low alloy steel, stainless steel and nickel alloys, and the second conduit is a nickel alloy (N) satisfying the following formula 1. T ) can include

[0008] [Formula 1] T ≤ 15 μm

[0009] (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 was prepared. When the cylindrical specimen was exposed to a gas stream containing 97.2 vol% NH3, 2.1 vol% H2, and 0.7 vol% N2, and a temperature environment of 500°C for 100 hours, the maximum depth of nitridation from the side of the cylindrical specimen in the direction of the central axis was measured by SEM (Scanning Electron Microscopy) and EDS (Energy Dispersive X-ray Spectroscopy).

[0010] In some embodiments, T ≤ 13 μm may be used in Equation 1.

[0011] In some embodiments, the first gas stream may contain ammonia at a concentration of 90% to 100% by volume, based on the total volume of the first gas stream.

[0012] In some embodiments, the second conduit may be made of the nickel-based alloy (N T ).

[0013] In some embodiments, the nickel-based alloy (N T ) may include 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.

[0014] In some embodiments, the conversion rate of ammonia in the chamber may be 1.4% or more.

[0015] In some embodiments, the chamber includes an inlet through which a first gas stream flows and an outlet through which a second gas stream is discharged. While ammonia is partially decomposed in the chamber, the inlet temperature of the chamber may be controlled to be 300°C to 410°C, and the outlet temperature of the chamber may be controlled to be 300°C to 600°C.

[0016] In some embodiments, the outlet temperature of the chamber may be controlled to be 300°C to 550°C.

[0017] In some embodiments, the difference between the inlet temperature and the outlet temperature of the chamber may be controlled to be 0°C to 200°C.

[0018] In some embodiments, the chamber may further include a catalyst-filled portion filled with a catalyst.

[0019] In some embodiments, the catalyst in the chamber may have a space velocity of 4,000 hr -1 or more.

[0020] In some embodiments, the inlet temperature of the first conduit may be controlled to 0°C to 200°C and the outlet temperature of the first conduit may be controlled to 200°C to 410°C while the first gas stream moves through the first conduit.

[0021] In some embodiments, the inlet temperature of the second conduit may be controlled to 410°C to 650°C and the outlet temperature of the second conduit may be controlled to 450°C to 700°C while the second gas stream moves through the second conduit.

[0022] In some embodiments, while the second gas stream moves through the second conduit, the temperature of the second gas stream from the inlet to the outlet of the second conduit may increase at a heating rate of 0.1°C / min to 10°C / min.

[0023] In some embodiments, the chamber may include at least one selected from the group consisting of low-alloy steel, stainless steel, and nickel-based alloys.

[0024] A carbon-free power generation system according to an embodiment of the present disclosure may include the aforementioned corrosion suppression system and a turbine power generation unit.

[0025] In some embodiments, the second gas stream can be supplied to the fuel supply conduit of the turbine power generation section.

[0026] The fuel cell system according to the embodiments of this disclosure may include the aforementioned corrosion suppression system and a fuel cell section comprising at least one fuel cell stack.

[0027] In some embodiments, the second gas stream can be supplied to the fuel supply conduit of the fuel cell section. [Effects of the Invention]

[0028] The corrosion suppression system according to the embodiments of this disclosure can achieve improved reaction reliability and energy efficiency.

[0029] The carbon-free power generation system according to the embodiments of this disclosure can achieve improved reaction reliability and energy efficiency.

[0030] The solid oxide fuel cell system according to the embodiments of this disclosure can achieve improved reaction reliability and energy efficiency.

[0031] If corrosion increases on the internal surfaces of the chamber, piping, or other components while ammonia is being supplied, hydrogen production efficiency may decrease, or the flow rate and purity of the hydrogen produced may become uneven.

[0032] However, in the corrosion suppression system according to the embodiments of the present disclosure, the structural stability of devices such as chambers and / or 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 embodiments of the present 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]

[0033] [Figure 1] Figure 1 is a schematic block diagram of a corrosion suppression 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 solid oxide 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, assuming an operating time of 36 hours for the chambers in Example 1, Example 1-1, and Example 1-2. [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 chambers in Example 1, Example 1-1, and Example 1-2. [Figure 6] Figure 6 shows SEM (Scanning Electron Microscope) images of the cross-sections of nitrided test specimens after evaluating the corrosion resistance based on the operating time of the chambers in Examples 1 to 5. [Figure 7] Figures 7a and 7b are SEM (Scanning Electron Microscope) images of the cross-sections of nitrided test specimens after evaluating the corrosion resistance of the second piping over operating time 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 chambers in Examples 1 to 5. [Figure 9] Figure 9 is a graph showing the evaluation results of the corrosion rate for the second pipe in Example 1 and Comparative Examples 2 and 3. [Modes for carrying out the invention]

[0034] 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. However, these embodiments are illustrative and not limiting to the present invention.

[0035] <Corrosion Inhibition System> Figure 1 is a schematic block diagram of a corrosion suppression system 100 according to an exemplary embodiment.

[0036] A corrosion suppression system 100 according to an exemplary embodiment of the present disclosure may include an ammonia supply unit 5, first conduits 10a and 10b (hereinafter referred to as "10") connected to the ammonia supply unit 5, an ammonia decomposition unit including a chamber 20 connected to the first conduit 10, and a second conduit 30 connected to the chamber 20.

[0037] A first gas stream containing ammonia may flow into the chamber 20 via the first conduit 10, where the ammonia is partially decomposed to produce hydrogen and nitrogen. A second gas stream containing unreacted ammonia, hydrogen, and nitrogen that was not decomposed in the chamber 20 may be discharged from the chamber 20 via the second conduit 30. The operating temperature of the chamber 20 may be 410°C or lower.

[0038] In other words, the chamber 20 can be configured to receive a first gas stream containing ammonia via the first conduit 10, partially decompose the ammonia to produce hydrogen (H2) and nitrogen (N2), and discharge a second gas stream containing unreacted ammonia, hydrogen (H2), and nitrogen (N2), and the chamber 20 can be configured to operate at an operating temperature of 410°C or lower.

[0039] The first conduit 10 and chamber 20 include at least one selected from the group consisting of carbon steel, low alloy steel, stainless steel, and nickel-based alloys, and the second conduit 30 is a nickel-based alloy (N) satisfying the following formula 1. T ) can include

[0040] [Formula 1] T ≤ 15 μm

[0041] In Equation 1, T is the nickel alloy (N T The specimen may be prepared as a cylindrical specimen with a cross-sectional diameter of 2 mm and a height of 200 mm, and 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 nitridation from the side of the cylindrical specimen in the direction of the central axis may be used. The depth can be measured by SEM (Scanning Electron Microscopy) and EDS (Energy Dispersive X-ray Spectroscopy) analysis.

[0042] As a result, the corrosion suppression system 100 can suppress or reduce corrosion in conduits and / or chambers during the process of decomposing or transferring ammonia.

[0043] As used herein, the term "nickel-based alloy" can be used to comprehensively include all alloys with nickel as the main component and one or more metal elements such as chromium (Cr), iron (Fe), molybdenum (Mo), cobalt (Co), aluminum (Al), titanium (Ti), tungsten (W), etc. added thereto.

[0044] Also, in this specification, an alloy satisfying the formula 1 is referred to as a "nickel-based alloy (N T )" to distinguish it from the above nickel-based alloy.

[0045] In some embodiments, the corrosion suppression system 100 can be provided as a system for decomposing ammonia into hydrogen or nitrogen.

[0046] In the case of high purity ammonia, it may rapidly corrode conduits and / or chambers at a high temperature exceeding 410°C.

[0047] In some embodiments, the conduit may be a pipe. For example, the first conduit may be the first pipe, and the second conduit may be the second pipe.

[0048] In the corrosion suppression system 100, by forming the second conduit 30, which can control the operating temperature of the chamber 20 to 410°C or lower and, if necessary, control the temperature to exceed 410°C, with the nickel-based alloy (N T ), nitridation within the entire system can be effectively prevented or reduced.

[0049] When metals forming components such as conduits and chambers are exposed to high-temperature, high-purity ammonia, they can undergo nitriding reactions with the ammonia, potentially forming nitride products from the surface into the interior of the metal. If these nitride products form inside the conduit or chamber, microscopic cracks may develop, reducing the flow characteristics of the gas stream and hindering reaction uniformity. This can ultimately lead to problems such as shortened conduit and chamber replacement cycles and increased maintenance costs.

[0050] The corrosion suppression system 100 ensures that even when high-purity ammonia comes into contact with the inner surface of the chamber 20, the nitriding reaction on the surface is significantly reduced or not accelerated in a temperature environment of 410°C or below.

[0051] Furthermore, the corrosion suppression system 100 ensures that nickel-based alloys satisfy the above formula 1 (N T On the inner surface of the second conduit 30, including the above, the nitriding reaction by ammonia can be suppressed or reduced even in high-temperature environments exceeding 410°C, thereby ensuring improved nitriding resistance.

[0052] For example, T, represented by equation 1, can be measured as follows.

[0053] Nickel alloy (N T When a 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, a nitrided cylindrical specimen can be obtained.

[0054] As used herein, the term "nitrided layer or nitrided portion" refers to a metal nitride formed by the diffusion of nitrogen into the metal (M x N y This refers to a region that has formed a structure, which can be experimentally confirmed, for example, by XRD analysis or SEM-EDS. In this region, the substrate metal forms a M such as Fe4N, CrN or other metal nitride phase. x Ny At the corresponding 2θ value, a metallic nitride phase may be detected by X-ray diffraction (XRD) analysis. On the other hand, the term "non-nitrided layer or non-nitrided portion" refers to a region of the metal substrate where such a nitride phase is not observed under the same analytical conditions.

[0055] 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).

[0056] 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.

[0057] 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.

[0058] 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.

[0059] Based on the elemental composition analysis, 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" can refer to the depth in the direction perpendicular to the outer surface (side) of the cylindrical test specimen, that is, the depth in the direction extending along the central axis of the cylinder. The smaller the maximum value of the nitrided depth, the higher the corrosion resistance can be evaluated.

[0060] The operating temperature of chamber 20 can refer to the average temperature and can be controlled to an average temperature of 410°C or less. The average temperature of chamber 20 can be calculated, for example, as the arithmetic mean temperature of the inlet and outlet temperatures of each conduit, or as the mass flow rate average temperature or spatial average temperature within each conduit. 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.

[0061] In some embodiments, the overall temperature of the chamber 20 can be controlled to 410°C or less.

[0062] In chamber 20, the ammonia contained in the first gas stream can be partially decomposed with an ammonia conversion rate of 1.4% or more, generating hydrogen and nitrogen.

[0063] The decomposition reaction of ammonia proceeds as shown in the following reaction equation and is an endothermic reaction.

[0064] [Reaction Equation] 2NH3 → N2 + 3H2

[0065] In some embodiments, the ammonia conversion rate in the chamber 20 may be 1.4% or higher, for example, 2.0% or higher, 7% or higher, 7.5% or higher, 10% or higher, 11% to 30%, or 15% to 25%.

[0066] The ammonia conversion rate (%) can be calculated using the following formula.

[0067] [Calculation formula] Ammonia conversion rate (%) = {(supplied ammonia flow rate) - (unreacted ammonia flow rate) / (supplied ammonia flow rate)} × 100

[0068] As a non-limiting example, the concentration of each gas in a gas mixture stream can be measured using conventional gas concentration analysis methods and corresponding analyzers. Examples of these methods and analyzers include gas chromatography (GC), Fourier transform infrared (FT-IR) spectroscopy, and mass spectrometry (MS).

[0069] In some embodiments of the corrosion suppression system 100, a second gas stream containing unreacted ammonia, hydrogen, and nitrogen that were not decomposed in the chamber 20 may be discharged from the chamber 20 and flow into the second conduit 30.

[0070] According to several embodiments of the corrosion suppression system 100, corrosion in the chamber 20 and the second conduit 30 can be suppressed, and improved reaction reliability and energy efficiency can be achieved.

[0071] As a non-limiting example, the corrosion suppression system 100 may include one or more first conduits 10 and / or second conduits 30, for example, one to ten, or one to seven, or one to five.

[0072] In some embodiments, T in formula 1 may be, for example, 13 μm or less, 12 μm or less, or 10 μm or less. This allows the corrosion suppression system 100 to further improve operational stability and energy efficiency.

[0073] In some embodiments, the corrosion suppression system 100 may further include, for example, an ammonia supply unit 5, a vaporization unit, a preheating unit, an adsorption unit, and / or a recovery unit, which can be connected to each other via connecting lines. The connecting lines may be, for example, connecting pipes. The connecting pipes may be made of carbon steel, low-alloy steel, stainless steel, and / or nickel-based alloys. The arrangement, length, etc., of the connecting pipes can be varied as needed.

[0074] In some embodiments, the first gas stream may contain ammonia in amounts of, for example, 90% to 100% by volume, 95% to 99.9% by volume, or 99% to 99.999% by volume.

[0075] As a non-limiting example, the first gas stream may contain 99.9% by volume of ammonia and trace amounts of impurities, such as water vapor, nitrogen, oxygen, and hydrogen.

[0076] In some embodiments, the chamber 20 may include an inlet into which a first gas stream flows and an outlet into which a second gas stream is discharged.

[0077] While ammonia is partially decomposed in chamber 20, the inlet temperature of chamber 20 can be controlled to 300°C to 410°C, and the outlet temperature of chamber 20 can be controlled to 300°C to 600°C.

[0078] In some embodiments, the outlet temperature of the chamber 20 can be controlled to 300°C to 550°C.

[0079] In some embodiments, the outlet temperature of the chamber 20 can be controlled to be 410°C or less, for example, between 300°C and 410°C.

[0080] In some embodiments, the temperature difference between the inlet temperature and outlet temperature of the chamber 20 can be controlled to 0°C to 200°C, for example, to 10°C to 150°C or 10°C to 100°C. This allows for better suppression of corrosion within the chamber 20 and enables control of the amount of hydrogen and nitrogen contained in the second gas stream.

[0081] In some embodiments, the internal temperature of the chamber 20 is 410°C or lower during the ammonia decomposition reaction and can be maintained at, for example, 250°C to 410°C, 270°C to 390°C, 270°C to 370°C, or 310°C to 370°C.

[0082] This allows for greater suppression of corrosion within the chamber 20 and enables control over the amounts of hydrogen and nitrogen contained in the second gas stream.

[0083] As a non-limiting example, the chamber 20 may have a heat exchanger type structure in which heat is continuously supplied, or it may have an adiabatic reactor type structure in which a preheated gas stream is supplied and the decomposition reaction takes place.

[0084] In some embodiments, while the first gas stream moves through the first conduit 10, the inlet temperature of the first conduit 10 can be controlled to, for example, 0°C to 200°C or 70°C to 160°C, and the outlet temperature of the first conduit 10 can be controlled to, for example, 200°C to 410°C or 250°C to 350°C.

[0085] In some embodiments, while the second gas stream moves through the second conduit 30, the inlet temperature of the second conduit 30 can be controlled to, for example, 410°C to 650°C or 450°C to 600°C, and the outlet temperature of the second conduit 30 can be controlled to, for example, 450°C to 700°C, 450°C to 600°C, or 600°C to 700°C.

[0086] In some embodiments, as the second gas stream moves through the second conduit 30, the temperature of the second gas stream from the inlet to the outlet of the second conduit 30 can be increased at a heating rate of 0.1°C / min to 10°C / min, or 1°C / min to 5°C / min.

[0087] This makes it possible to further suppress corrosion inside the second conduit 30.

[0088] In some embodiments, the second gas stream may contain 97.2% by volume or less of ammonia. The concentration of ammonia in the second gas stream may be, for example, 70.0% to 97.2% by volume, 70.0% to 90.0% by volume, 75.0% to 85.0% by volume, or 75.0% to 81.8% by volume.

[0089] This allows the reaction suppression system to achieve improved operational stability and energy efficiency.

[0090] In some embodiments, the chamber 20 may further include a catalyst-filled section packed with a catalyst. The catalyst-filled section may be, for example, a catalyst-filled tube. The catalyst-filled tube may be mounted inside the chamber 20.

[0091] In some embodiments, the catalyst in the chamber 20 is used for 4,000 hours. -1 The above space velocities can be obtained. Here, "space velocity" may also be volumetric space velocity, and the amount of gas that the catalyst can process per unit time (Nm³) 3 ( / hr) catalyst packing amount (Nm³ 3 This is the value obtained by dividing by ), and this can represent the amount of gas that a unit amount of catalyst can process per unit time.

[0092] The aforementioned spatial velocity is, for example, 4,000 hours. -1 ~120,000hr -1 , or 10,000hr -1~100,000hr -1 This may also be the case. This will suppress corrosion in the chamber 20 and effectively control the ammonia conversion rate.

[0093] In some embodiments, the catalyst may include an active metal supported on a carrier, and the carrier may be doped with a metal element. The carrier may be, for example, a zeolite or silica-alumina, and the metal element may include, for example, Zn, Co, Cu, K, Na, Cs, Mo, Se, Pd, Pt, Ba, Mg, Ca, etc.

[0094] In some embodiments, the first conduit 10 and the chamber 20 may be made of carbon steel, low-alloy steel, stainless steel, and / or nickel-based alloy.

[0095] In some embodiments, the first conduit 10 and the chamber 20 may include low-alloy steel, stainless steel, and / or nickel-based alloys.

[0096] 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. Non-limiting examples include alloying elements such as carbon, silicon, manganese, nickel, aluminum, chromium, phosphorus, sulfur, molybdenum, copper, and nitrogen.

[0097] The aforementioned stainless steel may include, for example, austenitic stainless steel, ferritic stainless steel, martensitic stainless steel, and the like.

[0098] In some embodiments, the first conduit 10 and the chamber 20 are made of a nickel-based alloy (N T ) can include

[0099] In some embodiments, the second conduit 30 is made of a nickel-based alloy (N TThis may include the following: This prevents or suppresses a decrease in the thermal conductivity of the second conduit 30, thereby achieving improved operational stability and energy efficiency.

[0100] In some embodiments, nickel alloys (N T The alloy may contain 40% to 80% by weight of nickel. The nickel content is based on the total weight of the nickel-based alloy.

[0101] In some embodiments, nickel alloys (N T The nickel content in the product may be, for example, 40% to 78% by weight, or 52% to 75% by weight.

[0102] In some embodiments, nickel alloys (N T These may include, for example, Ni-Cu-Fe alloys, Ni-Cr-Mo-W alloys, Ni-Cr-Fe-Mo alloys, and / or Ni-Cr-Co-W alloys.

[0103] The aforementioned nickel alloy (N T For example, it may include one or more alloys that are classified into any one of the groups selected from UNS N06601, UNS N06625, UNS N06690, UNS N07718, UNS N07792, and UNS N06002, based on the UNS (Unified Numbering System).

[0104] In some embodiments, the flow rate of at least one of the first gas stream and the second gas stream can be controlled from 1,000 kg / hr to 500,000 kg / hr, for example, from 1,000 kg / hr to 10,000 kg / hr, from 10,000 kg / hr to 250,000 kg / hr, or from 250,000 kg / hr to 500,000 kg / hr.

[0105] In some embodiments, the ammonia decomposition unit may further include an additional chamber connected to the chamber 20. The additional chamber connected to the chamber 20 may be included in the ammonia decomposition unit, for example, as a main cracker, and the nickel alloy (N T ) may include. Chamber 20 and the additional chamber can be connected via a connecting line. The connecting line may be, for example, a connecting tube, and the connecting tube may be made of the nickel alloy (N T ) can include

[0106] In some embodiments, the ammonia supply unit 5 can store and supply ammonia. The ammonia supply unit 5 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").

[0107] When the ammonia supply unit 5 stores and supplies liquid-phase ammonia, the corrosion suppression system 100 may include a vaporization unit that vaporizes the liquid-phase ammonia. For example, liquid-phase ammonia may be supplied from the ammonia supply unit 5 to the vaporization unit, and the vaporized gaseous ammonia from the vaporization unit by a vaporizer may be supplied to the chamber 20.

[0108] As a non-limiting example, the ammonia supply unit 5 may be an ammonia storage tank.

[0109] The corrosion suppression system 100 may include a preheating section connected to the vaporization section, in which the gaseous ammonia can be preheated by a preheater.

[0110] In some embodiments, the adsorption unit can separate or collect, for example, hydrogen, nitrogen, and / or ammonia.

[0111] The adsorption unit can separate and / or collect the aforementioned gases using methods such as temperature swing adsorption (TSA), pressure swing adsorption (PSA), or vacuum pressure swing adsorption (VPSA).

[0112] The adsorption section may include, for example, an adsorption tower filled with an adsorbent. The adsorption tower may be, for example, a configuration in which one or more adsorption towers are connected, a configuration in which one or more towers are connected to a single adsorption tower, or a combination thereof.

[0113] The adsorbent may include, for example, a hydrogen-selective adsorbent, a nitrogen-selective adsorbent, and / or an ammonia-selective adsorbent. The adsorbent 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.

[0114] In one embodiment, the structure of the zeolite may be, for example, in the form of CHA, LTA, and / or FAU.

[0115] In some embodiments, the recovery unit can recover and / or store, for example, off-gas streams, trim gas streams, etc., discharged from the second conduit 30 and / or the adsorption unit.

[0116] In some embodiments, the corrosion suppression system 100 may further include a power generation unit. The power generation unit can generate electricity by receiving fuel from the second conduit 30.

[0117] As a non-limiting example, the ammonia supply unit 5, ammonia decomposition unit, vaporization unit, preheating unit, adsorption unit, recovery unit, reaction heat supply unit, power generation unit, etc., may each include one or more inlets and / or outlets into which the gas stream flows in or out. They may also include one or more connecting lines connecting them, and such connecting lines may be connecting pipes. The connecting pipes may be made of, for example, carbon steel, low-alloy steel, stainless steel, and / or nickel-based alloys. The arrangement, length, etc., of the connecting pipes can be varied as needed.

[0118] In some embodiments, the corrosion suppression system 100 may further include a monitoring unit that includes a temperature sensor, a flow rate sensor, and the like. The monitoring unit may include a controller that, after detecting, for example, temperature, flow rate, etc., controls them within a set range.

[0119] As a non-limiting example, the corrosion suppression system 100 may include an operating temperature control device to maintain the operating temperature of the chamber 20 at approximately 410°C or lower. For example, the operating temperature control device may include a heater, a thermocouple, and / or a controller. The heater may be a heating means operated by, for example, an electric resistance heater, an induction heater, or an external heat source. The thermocouple can maintain the temperature range by sensing the temperature inside the chamber 20 in real time, and the controller can maintain the temperature range by controlling the operation of the heater based on the temperature information. The operating temperature control device is not particularly limited in its configuration or installation method.

[0120] According to embodiments of the present disclosure, ammonia can be decomposed using a corrosion suppression system 100. The ammonia decomposition method according to embodiments of the present disclosure may include the step of using a corrosion suppression system 100.

[0121] According to some embodiments, an ammonia decomposition method using a corrosion suppression system 100 may include an ammonia supply unit 5, a first conduit 10 fluidly connected to the ammonia supply unit 5, an ammonia decomposition unit including a chamber 20 fluidly connected to the first conduit 10, and a second conduit 30 fluidly connected to the chamber 20.

[0122] A first gas stream containing ammonia is introduced into the chamber 20 via the first conduit 10, where the ammonia is partially decomposed to produce hydrogen and nitrogen. A second gas stream containing the remaining ammonia, hydrogen, and nitrogen can then be discharged from the chamber 20. The operating temperature of the chamber 20 may be 410°C or lower.

[0123] The first conduit 10 and the chamber 20 may include at least one selected from the group consisting of carbon steel, low-alloy steel, stainless steel, and nickel-based alloys.

[0124] The second conduit 30 is made of a nickel-based alloy (N) that satisfies the following formula 1. T ) can include

[0125] [Formula 1] T ≤ 15 μm

[0126] In Equation 1, T may be the maximum depth of nitrided material from the side of the cylindrical specimen in the central axis direction when the nickel alloy (NT) is prepared as a cylindrical specimen with a cross-sectional diameter of 2 mm and a height of 200 mm, and the cylindrical specimen is exposed for 100 hours 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. The depth can be measured by SEM (Scanning Electron Microscopy) and EDS (Energy Dispersive X-ray Spectroscopy) analysis.

[0127] According to some embodiments, the ammonia decomposition method includes introducing a first gas stream containing ammonia into a chamber 20 via first conduits 10a and 10b, partially decomposing the ammonia in the chamber 20 to produce hydrogen and nitrogen, and discharging a second gas stream containing the remaining ammonia, hydrogen, and nitrogen from the chamber 20, wherein the operating temperature of the chamber 20 may be 410°C or lower.

[0128] For example, in the ammonia decomposition method described above, while the first gas stream flows through the first conduits 10a and 10b, the inlet temperatures of the first conduits 10a and 10b can be controlled to a range of 0°C to 200°C, and the outlet temperatures of the first conduits 10a and 10b can be controlled to a range of 200°C to 410°C.

[0129] For example, in the ammonia decomposition method described above, while the second gas stream flows through the second conduit 30, the inlet temperature of the second conduit 30 may be controlled to be in the range of 410°C to 650°C, and the outlet temperature of the second conduit 30 may be controlled to be in the range of 450°C to 700°C.

[0130] <Carbon-free power generation system> Figure 2 is a schematic block diagram of a carbon-free power generation system 200 according to one embodiment of the present disclosure.

[0131] The carbon-free power generation system 200 includes the aforementioned corrosion suppression system 100 and the turbine power generation unit 40, and can generate electrical energy without reducing long-term reaction reliability and energy efficiency.

[0132] In some embodiments, the turbine power generation unit may include a gas turbine generator.

[0133] In some embodiments, the second gas stream can be supplied to the fuel supply conduit of the turbine power generation unit 40. The turbine power generation unit 40 can generate electricity using the second gas stream as fuel.

[0134] The second conduit 30 and the turbine generator can be connected via a connecting line. The connecting line may be a connecting pipe and may be made of, for example, carbon steel, low-alloy steel, stainless steel, and / or nickel-based alloys.

[0135] The connecting pipe is, for example, made of a nickel-based alloy (N T ) can include

[0136] As a non-limiting example, the 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.

[0137] 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).

[0138] In the aforementioned gas turbine generator, waste heat can be generated through various paths in the form of combustion gas, exhaust gas, etc.

[0139] 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 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.

[0140] In some embodiments, the carbon-free power generation system may further include an exhaust gas processing unit. The exhaust gas processing unit can process the exhaust gas generated in, for example, a gas turbine power generation unit or a combustion unit by methods such as cooling, filtering, neutralizing, or adsorption.

[0141] 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.

[0142] 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.

[0143] <Fuel cell system> Figure 3 is a schematic block diagram of a fuel cell system 300 according to one embodiment of the present disclosure.

[0144] The solid oxide fuel cell system 300 includes the aforementioned corrosion suppression system 100 and a fuel cell unit 50 including at least one fuel cell stack, and can generate electrical energy without long-term degradation of reaction reliability and energy efficiency.

[0145] In some embodiments, the fuel cell system may be a solid oxide fuel cell (SOFC) system.

[0146] In some embodiments, the second gas stream can be supplied to the fuel supply conduit of the fuel cell unit 50. The fuel cell unit 50 can generate electricity using the second gas stream as fuel.

[0147] As a non-limiting example, the fuel cell unit 50 may further include a fuel supply unit connected to a fuel supply conduit, 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.

[0148] 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.

[0149] As a non-limiting example, the cathode may be connected to an air supply unit and receive pressurized and heated air.

[0150] As a non-limiting example, the anode may be connected to the fuel supply unit and receive a supply of fuel containing hydrogen produced in the fuel supply unit.

[0151] The second conduit 30 and the fuel cell stack can be connected via a connecting line. The connecting line may be a connecting pipe and may be made of, for example, carbon steel, low-alloy steel, stainless steel, and / or nickel-based alloys.

[0152] The connecting pipe is, for example, made of a nickel-based alloy (N T ) can include

[0153] In some embodiments, the fuel cell system may further include an exhaust gas processing unit. The above description can be used to describe the exhaust gas processing unit.

[0154] The corrosion suppression system 100, the carbon-free power generation system 200, and / or the fuel cell system 300 according to embodiments of the present disclosure can be used in various application fields, such as fuel cell systems, ship power generation systems, power supply systems, and combined heat and power generation systems.

[0155] 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.

[0156] Example 1 A corrosion-inhibiting system was designed that sequentially includes an ammonia storage tank made of SUS304 material, a first piping made of SUS304 material, an ammonia decomposition section including a chamber made of SUS304 material, and a second piping made of Inconel 625 material. The corrosion-inhibiting system was implemented according to the conditions in Tables 1 and 2 below. Here, the operating temperature may refer to the average temperature. The chamber is fitted with a filled tube that is filled with a catalyst.

[0157] 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.

[0158] Example 3 Except for the chamber being made of carbon steel, the same system as in Example 1 was carried out according to the conditions in Tables 1 and 2 below.

[0159] Example 4 A system similar to that in Example 1 was implemented according to the conditions in Tables 1 and 2 below.

[0160] Example 5 A system similar to that in Example 1 was implemented according to the conditions in Tables 1 and 2 below.

[0161] 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 it did not include a chamber.

[0162] 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.

[0163] 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.

[0164] 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.

[0165] [Table 1]

[0166] [Table 2]

[0167] 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 chamber and the second pipe was evaluated using metal test specimens made of the same material as their inner surfaces (hereinafter referred to as "corresponding metal test specimens").

[0168] Under substantially identical atmospheric conditions, the nitriding reaction by ammonia occurring on the inner surfaces of the chamber and the second pipe can be carried out on the surface of the corresponding metal test piece using the same reaction equation and at substantially the same rate, even taking into account the effects of test errors and differences in surface conditions.

[0169] Therefore, the evaluation results of corrosion resistance on corresponding metal test pieces were used as an index for evaluating the corrosion resistance of the inner surfaces of the chamber and the second pipe.

[0170] (1) Corrosion resistance due to chamber operating temperature 1) In Example 1, a metal test piece made of the same material as the chamber (SUS304) 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").

[0171] 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.

[0172] A gas stream supply section, a gas stream discharge section, and a vertical quartz tube reactor connected to a furnace were prepared.

[0173] 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.

[0174] 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.

[0175] 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.

[0176] 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:

[0177] 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.

[0178] [Table 3]

[0179] 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.

[0180] [Table 4]

[0181] From Tables 3 and 4 and Figures 4 and 5 above, it was confirmed that corrosion on the inner surface of the chamber begins to increase rapidly at temperatures above 410°C. Furthermore, as the operating time under conditions above 410°C increased, the corrosion rate on the inner surface of the chamber accelerated even further.

[0182] (2) Corrosion resistance due to chamber operating time In Examples 1 to 5, metal test specimens made of the same material as the chamber were prepared in a cylindrical shape with a circular cross-sectional diameter of 2 mm and a height of 200 mm (hereinafter referred to as "cylindrical test specimens").

[0183] A gas stream supply section, a gas stream discharge section, and a vertical quartz tube reactor connected to a furnace were prepared.

[0184] 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 chamber corresponding to Table 1.

[0185] Subsequently, the cylindrical specimens were exposed to the environment corresponding to Table 1 for 100 hours from the time the chamber reached its operating temperature to obtain nitrided cylindrical specimens.

[0186] 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.

[0187] (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").

[0188] A gas stream supply section, a gas stream discharge section, and a vertical quartz tube reactor connected to a furnace were prepared.

[0189] 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.

[0190] 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.

[0191] 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

[0192] [Table 5]

[0193] Referring to Table 5 above, in Example 3, where a carbon steel chamber was used, the corrosion level during long-term operation was relatively high.

[0194] 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.

[0195] In Example 5, the hydrogen concentration in the gas stream supplied to the second piping was relatively low, resulting in reduced corrosion resistance.

[0196] In Comparative Examples 1 and 4, a gas stream containing 99.99999 volume% ammonia was supplied directly to the high-temperature second piping without passing through the chamber, resulting in rapid nitriding and degraded reliability and stability during long-term operation. In Comparative Example 4, the corrosion rate increased even further because the second piping was manufactured from Inconel 601 material.

[0197] 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.

[0198] Experimental Example 2: Evaluation of Corrosion Rate (1) Corrosion rate of the chamber In Examples 1 to 5, metal test specimens made of the same material as the chamber were prepared in a cylindrical shape with a circular cross-sectional diameter of 2 mm and a height of 200 mm (hereinafter referred to as "cylindrical test specimens").

[0199] A gas stream supply section, a gas stream discharge section, and a vertical quartz tube reactor connected to a furnace were prepared.

[0200] 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 chamber corresponding to Table 1.

[0201] Subsequently, cylindrical 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 chamber reached its operating temperature, to obtain nitrided cylindrical specimens.

[0202] 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.

[0203] [Table 6]

[0204] According to Table 6, in Example 3, where a carbon steel chamber 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℃.

[0205] (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").

[0206] A vertical quartz tube reactor connected to the gas stream supply unit and furnace was prepared.

[0207] 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.

[0208] 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.

[0209] 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.

[0210] [Table 7]

[0211] 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.

[0212] 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. It includes an ammonia supply unit, a first conduit connected to the ammonia supply unit, an ammonia decomposition unit including a chamber connected to the first conduit, and a second conduit connected to the chamber, A first gas stream containing ammonia flows into the chamber via the first conduit, where the ammonia is partially decomposed to produce hydrogen and nitrogen, and a second gas stream containing unreacted ammonia, hydrogen, and nitrogen that was not decomposed in the chamber is discharged from the chamber. The operating temperature of the chamber is 410°C or lower. The first conduit and the chamber include at least one selected from the group consisting of carbon steel, low alloy steel, stainless steel, and nickel-based alloys. The second conduit is made of a nickel-based alloy (N) that satisfies the following formula 1. Ｔ Corrosion control 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 central axis direction after exposure to a gas stream containing and a temperature environment of 500°C for 100 hours, and the depth was measured by SEM (Scanning Electron Microscope) and EDS (Energy Dispersive X-ray Spectroscopy).

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

3. The corrosion suppression system according to claim 1, wherein the first gas stream contains ammonia at a concentration of 90% to 100% by volume, based on the total volume of the first gas stream.

4. The second conduit is made of the nickel-based alloy (N Ｔ A corrosion suppression system according to claim 1, comprising the following components.

5. The aforementioned nickel alloy (N Ｔ The corrosion suppression system according to claim 1, comprising one or more alloys classified into any one selected from the group consisting of UNS N06601, UNS N06625, UNS N06690, UNS N07718, UNS N07792, and UNS N06002, based on the UNS (Unified Numbering System).

6. The corrosion suppression system according to claim 1, wherein the ammonia conversion rate in the chamber is 1.4% or more.

7. The chamber includes an inlet into which a first gas stream flows and an outlet into which a second gas stream is discharged. The corrosion suppression system according to claim 1, wherein, while ammonia is partially decomposed in the chamber, the inlet temperature of the chamber is controlled to 300°C to 410°C, and the outlet temperature of the chamber is controlled to 300°C to 600°C.

8. The corrosion suppression system according to claim 7, wherein the outlet temperature of the chamber is controlled to 300°C to 550°C.

9. The corrosion suppression system according to claim 7, wherein the difference between the inlet temperature of the chamber and the outlet temperature of the chamber is controlled to be between 0°C and 200°C.

10. The corrosion suppression system according to claim 1, wherein the chamber further includes a catalyst-filled section filled with a catalyst.

11. The catalyst in the chamber is 4,000 hr －１ The corrosion suppression system according to claim 10, having the above spatial velocity.

12. The corrosion suppression system according to claim 1, wherein, while the first gas stream moves through the first conduit, the inlet temperature of the first conduit is controlled to be between 0°C and 200°C, and the outlet temperature of the first conduit is controlled to be between 200°C and 410°C.

13. The corrosion suppression system according to claim 1, wherein, while the second gas stream moves through the second conduit, the inlet temperature of the second conduit is controlled to 410°C to 650°C, and the outlet temperature of the second conduit is controlled to 450°C to 700°C.

14. The corrosion suppression system according to claim 1, wherein while the second gas stream moves through the second conduit, the temperature of the second gas stream from the inlet to the outlet of the second conduit is increased at a heating rate of 0.1°C / min to 10°C / min.

15. The corrosion suppression system according to claim 1, wherein the chamber comprises at least one selected from the group consisting of low-alloy steel, stainless steel, and nickel-based alloys.

16. A carbon-free power generation system comprising the corrosion suppression system described in claim 1 and a turbine power generation unit.

17. The carbon-free power generation system according to claim 16, wherein the second gas stream is supplied to the fuel supply conduit of the turbine power generation unit.

18. A fuel cell system comprising the corrosion suppression system according to claim 1 and a fuel cell section including at least one fuel cell stack.

19. The fuel cell system according to claim 18, wherein the second gas stream is supplied to the fuel supply conduit of the fuel cell section.

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