Hydrogen production plant for producing hydrogen from ammonia

Abstract

The hydrogen production apparatus of the present invention comprises: an ammonia decomposition reactor, which decomposes ammonia to discharge a mixed gas containing hydrogen, nitrogen, and unreacted ammonia; an ammonia remover, which receives the mixed gas, adsorbs and removes unreacted ammonia contained in the mixed gas, and discharges a first generated gas and a first tail gas containing hydrogen and nitrogen; and a nitrogen remover, which receives the first generated gas, removes nitrogen contained in the first generated gas, and discharges a second generated gas and a second tail gas containing hydrogen, wherein the second generated gas discharged from the nitrogen remover is supplied back to the nitrogen remover as a cleaning gas and a pressurizing gas. The hydrogen production apparatus according to the present invention can continuously produce high-purity hydrogen in large quantities.

Description

Technical Field

[0001] This invention relates to a hydrogen production apparatus for producing hydrogen from ammonia. Background Technology

[0002] Hydrogen production technologies can generally be divided into: gray hydrogen technology, which produces carbon dioxide during the process of producing hydrogen from fossil fuels; blue hydrogen technology, which uses low-rank coal, petroleum coke, biomass, waste, etc., which are unused energy sources, to produce syngas and then modifies it to produce hydrogen; and green hydrogen technology, which uses renewable energy and produces hydrogen through the electrolysis of water.

[0003] Green hydrogen is considered a next-generation energy source, but due to the high cost of hydrogen production, research on hydrogen production through natural gas reforming and ammonia decomposition is ongoing. However, the natural gas reforming process emits carbon dioxide again during hydrogen production; therefore, the importance of hydrogen production processes utilizing ammonia, which does not produce carbon dioxide during the reaction, is gradually increasing.

[0004] In particular, ammonia has a concentration of 120 kg / m³. 3 With its ultra-high capacity hydrogen storage and transport capabilities, it can utilize almost directly existing storage and transport infrastructure, and is therefore emphasized as an essential technology for achieving carbon neutrality.

[0005] Hydrogen produced from ammonia decomposition has various applications. To ensure its use as a fuel of high quality, ammonia removal and high-purity hydrogen are necessary. The removal of unreacted residual ammonia and hydrogen / nitrogen separation processes are core elements in producing high-purity hydrogen. These processes typically employ temperature swing adsorption (TSA) or pressure swing adsorption (PSA). PSA separates gases by changing the pressure of the adsorbent to adsorb the adsorbate. The PSA process involves a series of steps including adsorption / desorption / pressurization / depressurization. By varying the pressure, temperature, and gas flow rate at each step, product quality and recovery rate can be ensured. However, due to the trade-off between recovery rate and purity, a process that can improve recovery rate while ensuring high purity is needed in the PSA process. Summary of the Invention

[0006] (a) Technical problems to be solved According to one aspect of the present invention, a hydrogen production apparatus for mass production of high-purity hydrogen can be provided.

[0007] According to one aspect of the present invention, a hydrogen production apparatus that reduces the amount of raw materials added and the amount of emitted gases can be provided.

[0008] (II) Technical Solution According to one embodiment of the present invention, a hydrogen production apparatus is provided, comprising: an ammonia decomposition reactor, which decomposes ammonia to discharge a mixed gas containing hydrogen, nitrogen, and unreacted ammonia; an ammonia remover, which receives the mixed gas, adsorbs and removes unreacted ammonia contained in the mixed gas, and discharges a first product gas and a first tail gas; and a nitrogen remover, which receives the first product gas, removes nitrogen contained in the first product gas, and discharges a second product gas and a second tail gas, wherein the second product gas discharged from the nitrogen remover is supplied back to the nitrogen remover as a cleaning gas and a pressurizing gas.

[0009] According to another specific embodiment of the present invention, a hydrogen production apparatus is provided, wherein the first tail gas discharged from the ammonia remover is supplied again to the ammonia decomposition reactor as a combustion gas for burning to remove unreacted ammonia, the first generated gas discharged from the ammonia remover is supplied again to the ammonia remover as a pressurizing gas, and the second tail gas discharged from the nitrogen remover is supplied again to the ammonia remover as a cleaning gas.

[0010] According to another specific embodiment of the present invention, a hydrogen production apparatus is provided, wherein the first generated gas comprises 75-80% by volume hydrogen and 20-25% by volume nitrogen.

[0011] According to another specific embodiment of the present invention, a hydrogen production apparatus is provided, wherein a first tail gas comprises 10-20% by volume hydrogen, 40-45% by volume nitrogen and 40-45% by volume ammonia.

[0012] According to another specific embodiment of the present invention, a hydrogen production apparatus is provided, wherein the first generated gas contains 0.3-1 ppm of ammonia.

[0013] According to another specific embodiment of the present invention, a hydrogen production apparatus is provided, wherein the second generated gas contains more than 99% by volume hydrogen.

[0014] According to another specific embodiment of the present invention, a hydrogen production apparatus is provided, wherein a second tail gas comprises 25-30% by volume hydrogen and 70-75% by volume nitrogen.

[0015] According to another specific embodiment of the present invention, a hydrogen production apparatus is provided, wherein the second tail gas contains 0.5-1 ppm of ammonia.

[0016] According to another specific embodiment of the present invention, a hydrogen production apparatus is provided, wherein the ammonia remover and the nitrogen remover comprise carbon molecular sieve (CMS), zeolite, metal-organic framework (MOF), or covalent organic framework (COF) as adsorbents.

[0017] According to another specific embodiment of the present invention, a hydrogen production apparatus is provided, wherein the adsorption time in the ammonia remover is 360-480 seconds and the adsorption pressure is 7-8 bar (gauge pressure) (barG).

[0018] According to another specific embodiment of the present invention, a hydrogen production apparatus is provided, wherein the adsorption time in the nitrogen remover is 240-360 seconds and the adsorption pressure is 7-8 bar (gauge pressure) (barG).

[0019] (III) Beneficial Effects According to one specific embodiment of the present invention, the purity of the produced hydrogen can be improved.

[0020] According to one specific embodiment of the present invention, high-purity hydrogen can be produced continuously in large quantities.

[0021] According to a specific embodiment of the present invention, environmental pollution generated during hydrogen production can be reduced. Attached Figure Description

[0022] Figure 1 This is a schematic diagram illustrating a hydrogen production apparatus according to a specific embodiment of the present invention.

[0023] Figure 2 This is a schematic diagram illustrating the process of an ammonia decomposition reactor according to a specific embodiment of the present invention.

[0024] Figure 3 This is a schematic diagram illustrating the process of an ammonia removal device according to a specific embodiment of the present invention.

[0025] Figure 4 This is a schematic diagram illustrating the process of a nitrogen removal device according to a specific embodiment of the present invention.

[0026] Figure 5 This is a graph showing the pressure changes inside the ammonia remover.

[0027] Figure 6 This is a graph showing the pressure changes inside the nitrogen remover.

[0028] Figure 7This is a graph showing the concentration of ammonia in the first generated gas and the concentration of ammonia in the second generated gas.

[0029] Figure 8 This is a graph showing the hydrogen concentration of the second generated gas. Best practice

[0030] The present invention will now be described in detail with reference to the accompanying drawings. However, this is merely exemplary, and the present invention is not limited to the specific embodiments described herein.

[0031] Figure 1 This is a schematic diagram illustrating a hydrogen production apparatus according to a specific embodiment of the present invention.

[0032] Referring to the above Figure 1 According to a specific embodiment of the present invention, a hydrogen production apparatus includes an ammonia decomposition reactor 101, an ammonia remover 201, and a nitrogen remover 301.

[0033] The ammonia remover 201 and nitrogen remover 301 of the present invention can remove ammonia and nitrogen respectively through pressure swing adsorption (PSA) process. By operating the two processes in tandem, the generated gases and tail gases produced in each process can be recovered and reused.

[0034] Figure 2 This diagram schematically illustrates the process of an ammonia decomposition reactor 101 according to a specific embodiment of the present invention. The ammonia decomposition reactor 101 decomposes ammonia to produce hydrogen and nitrogen. Specifically, the ammonia decomposition reactor 101 decomposes ammonia to discharge a mixed gas containing hydrogen, nitrogen, and unreacted ammonia.

[0035] There can be one or more ammonia decomposition reactors 101. When there are two or more ammonia decomposition reactors 101, ammonia can be divided into small portions and decomposed simultaneously, and the temperature of the ammonia decomposition reactors 101 can be uniformly controlled, thus improving efficiency.

[0036] The reaction equation for the decomposition of ammonia can be shown below; it is an endothermic reaction.

[0037] Ammonia decomposition reaction: 2NH3 → N2 + 3H2 (ΔH = 46 kJ / mol) According to one specific embodiment, the ammonia decomposition reactor 101 may include a reaction section 102 that generates the aforementioned ammonia decomposition reaction to produce nitrogen and hydrogen. The internal temperature of the reaction section 102 may be, for example, 500-650°C, but the temperature conditions can vary depending on the process configuration and the catalyst used. The internal pressure of the reaction section 102 is not particularly limited, and may be, for example, 0-7 bar (gauge pressure). This pressure range can vary depending on the operating pressure of downstream ammonia remover 201, nitrogen remover 301, etc., of the ammonia decomposition reactor 101.

[0038] According to one specific embodiment, the ammonia decomposition reactor 101 may include a combustion section 103 that supplies heat to the reaction section 102. The combustion section 103 can heat the reaction section 102 by burning air and fuel, and can supply the heat to the reaction section 102.

[0039] Fuel and combustion air can be supplied to the combustion unit 103, and heat can be generated through the combustion reaction with oxygen in the combustion air. The fuel is not particularly limited, as long as it is a fuel commonly used in combustion reactions, such as fossil fuel-based LNG or LPG. However, in order to preemptively block CO2 emissions, hydrogen and ammonia can be mixed and used for combustion.

[0040] The internal temperature of the combustion section 103 is not particularly limited, for example, it can be 700-1000°C. Within the above temperature range, the combustion section 103 can efficiently heat the reaction section 102 to carry out the ammonia decomposition reaction.

[0041] The ammonia decomposition reactor 101 may include a catalyst as needed to improve the decomposition reaction efficiency. The catalyst may be a conventional catalyst used in ammonia decomposition, specifically a nickel-based catalyst, a ruthenium-based catalyst, etc.

[0042] One specific embodiment may further include a liquid ammonia storage tank 104 for supplying liquid ammonia to the ammonia decomposition reactor 101. It may also further include an ammonia pump (not shown) for supplying the liquid ammonia.

[0043] One specific implementation may further include an air blower 105 that supplies combustion air to the combustion section 103 from the outside in the ammonia decomposition reaction process.

[0044] Figure 3 This diagram schematically illustrates the process of an ammonia removal device 201 according to a specific embodiment of the present invention. The ammonia removal device 201 according to one embodiment receives a mixed gas discharged from the ammonia decomposition reactor 101 and can adsorb and remove unreacted ammonia contained in the mixed gas. Specifically, the ammonia removal device 201 adsorbs and removes unreacted ammonia contained in the mixed gas and discharges a first product gas and a first tail gas containing hydrogen and nitrogen. The first product gas discharged from the ammonia removal device 201 is supplied to a nitrogen removal device 301.

[0045] According to a specific embodiment of the present invention, the first tail gas discharged from the ammonia remover 201 can be supplied again to the ammonia decomposition reactor 101 as a combustion gas for burning to remove unreacted ammonia.

[0046] According to a specific embodiment of the present invention, a portion of the first generated gas discharged from the ammonia remover 201 can be supplied back to the ammonia remover 201 as pressurized gas.

[0047] The first generated gas may contain 75-80% by volume hydrogen, 20-25% by volume nitrogen, and 0.3-1 ppm ammonia.

[0048] The first exhaust gas may contain 10-20% by volume hydrogen, 40-45% by volume nitrogen, and 40-45% by volume ammonia.

[0049] The first tail gas discharged from the ammonia remover 201 can be supplied back to the ammonia decomposition reactor 101 as combustion gas. For example, the first tail gas can be fed to the combustion section 103 of the ammonia decomposition reactor for use as fuel. The first tail gas contains ammonia. By using unreacted ammonia as fuel for combustion, the energy efficiency of the ammonia decomposition reactor 101 can be improved, and unreacted ammonia can be removed by combustion. Alternatively, the ammonia contained in the first tail gas fed to the combustion section 103 can be mixed with fuel used for the decomposition reaction and burned as fuel.

[0050] When a portion of the first generated gas discharged from ammonia remover 201 is supplied back to ammonia remover 201 as pressurized gas, the nitrogen partial pressure within ammonia remover 201 decreases, reducing nitrogen adsorption and improving the adsorption performance of ammonia remover 201. Improved adsorption performance of ammonia remover 201 increases the breakthrough time of the adsorption tower, ultimately reducing the total cycle time of the ammonia removal process. Reduced circulation in the ammonia removal process of ammonia remover 201 reduces the amount of gas consumed as purge gas, thus reducing the amount of hydrogen ultimately wasted. Consequently, the overall recovery rate of the process increases.

[0051] Ammonia adsorption is the selective adsorption of ammonia from a mixture of hydrogen, nitrogen, and unreacted ammonia. An adsorbent can be used to adsorb ammonia. The ammonia remover 201 may include multiple adsorption towers. The adsorbent is not particularly limited as long as it is a substance that can selectively adsorb ammonia, but it must be an adsorbent with high ammonia selectivity. The ammonia selectivity of the adsorbent must be the highest, and it is preferably an adsorbent with higher nitrogen selectivity than hydrogen selectivity. For example, it can be at least one selected from carbon molecular sieves (CMS), zeolites, metal-organic frameworks (MOFs), covalent organic frameworks (COFs), activated carbon, alumina, silica, etc. Table 1 shows the adsorption performance of CMS adsorbent as an example.

[0052] [Table 1] In the ammonia remover 201, the adsorbent that adsorbs ammonia undergoes processes such as depressurization and cleaning. This regeneration of the adsorbent allows for the desorption and recovery of ammonia, and the desorbed ammonia can be reused. Specifically, to regenerate the adsorbent, the ammonia remover 201 can desorb ammonia through a cleaning process. The cleaning of the ammonia remover 201 can be divided into high-temperature cleaning and low-temperature cleaning. High-temperature cleaning refers to the process of desorbing ammonia adsorbed in the adsorbent of the ammonia remover 201 using high-temperature nitrogen gas, while low-temperature cleaning refers to the process of cooling the adsorbent.

[0053] The ammonia remover 201 may include: a first generated gas storage tank 202, which stores a first generated gas containing hydrogen and nitrogen for ammonia removal; and a first tail gas storage tank 203, which stores the ammonia removed from the ammonia remover 201. In this case, the first generated gas stored in the first generated gas storage tank 202 is supplied to the nitrogen remover 301.

[0054] The ammonia removal unit 201 can undergo processes of equalization, pressurization, adsorption, depressurization and desorption. Figure 5 The diagram shows the internal pressure changes of an adsorption tower for both the ammonia and nitrogen removal units.

[0055] The ammonia removal unit 201 may include multiple adsorption towers. In this case, the adsorption towers operate simultaneously and in conjunction. Table 2 shows the cycle of four adsorption towers according to an exemplary specific embodiment. One cycle may have a required time of approximately 28 minutes. After one cycle is completed, the next cycle begins immediately. By repeating the cycle in multiple adsorption towers, the ammonia removal process can be carried out continuously.

[0056] The following description of the adsorption tower circulation according to an exemplary embodiment is merely illustrative of the invention and is not intended to limit the scope of the claims. Various changes and modifications can be made within the scope and technical concept of the invention, which will be apparent to those skilled in the art.

[0057] [Table 2] Each symbol represents the following process.

[0058] ADS (Adsorption): Adsorption process EQ1 (Pressure Equalization): Primary pressure equalization process EQ2 (Equalizing Pressure): Secondary equalizing pressure process REST (rest): Rest process BD (Blowdown): Pressure Reduction Process PR (pressurization): Pressurization process PG (purge): Desorption process Pressure equalization is the process of uniformizing the pressure between two or more adsorption towers. It can be divided into two steps: primary pressure equalization and secondary pressure equalization. Each adsorption tower includes valves connected to different adsorption towers. The pressure equalization process can be performed by opening and closing these valves according to the process sequence.

[0059] The first equalization process involves opening the valves of both the adsorption tower that has undergone the desorption process and the adsorption tower that has undergone the resting phase, thus equalizing the pressure of the adsorption tower after the desorption process with that of the adsorption tower after the resting phase. The first equalization process can last approximately 30 seconds. The pressure of the adsorption tower after the first equalization process can reach approximately 1 bar (gauge pressure).

[0060] The secondary pressure equalization process involves opening the valves of both the adsorption tower that underwent the primary pressure equalization process and the adsorption tower that underwent the secondary pressure equalization process, bringing their pressures together. This secondary pressure equalization process can last approximately 30 seconds. The pressure in the adsorption tower after the secondary pressure equalization process can reach approximately 4 bar (gauge pressure).

[0061] After the secondary pressure equalization process is completed, a pressurization process is performed. The first generated gas discharged from the ammonia remover 201 is used as the pressurization gas for the ammonia remover 201 and supplied again. The supply of pressurization gas can pressurize the pressure inside the adsorption tower from about 4 bar (gauge pressure) to about 7.5 bar (gauge pressure) in about 390 seconds.

[0062] After the pressurization process is completed, the adsorption process is carried out. Mixed gas is received from the ammonia decomposition reactor 101, and ammonia is adsorbed and removed. The adsorption time of the ammonia remover 201 is 360-480 seconds, and the adsorption pressure can be 7-8 bar (gauge pressure). When the adsorption time is 360-480 seconds, it has the advantage of maintaining the ammonia removal rate. When the adsorption time is greater than 480 seconds, the adsorption tower no longer adsorbs ammonia and discharges it, thus resulting in a decrease in the ammonia removal rate. When the adsorption pressure is 7-8 bar (gauge pressure), it has the advantage of maximizing the ammonia removal rate. When the adsorption pressure is less than 7 bar (gauge pressure), due to impurities, the amount of ammonia that the adsorbent can adsorb decreases, thus resulting in the ammonia being discharged without being removed.

[0063] After the adsorption process is completed, a secondary pressure equalization process is performed. Open the valves of both the adsorption tower that underwent the initial adsorption process and the adsorption tower that underwent the primary pressure equalization process, so that the pressure in the adsorption tower after the initial process is the same as the pressure in the adsorption tower after the primary pressure equalization process. The secondary pressure equalization process can last approximately 30 seconds. The pressure in the adsorption tower after the secondary pressure equalization process can be approximately 4 bar (gauge pressure).

[0064] Afterward, the adsorption tower enters a resting phase. The resting phase can last for approximately 360 seconds.

[0065] After the resting step, a pressure equalization process is performed. Open the valves of both the adsorption tower that has undergone the resting step and the adsorption tower that has undergone the desorption process, so that the pressure of the adsorption tower after the resting step is the same as that of the adsorption tower after the desorption process. The pressure of the adsorption tower after the pressure equalization process can be approximately 1 bar (gauge pressure). The pressure equalization process can last approximately 30 seconds.

[0066] Next, a depressurization process is performed. This process adjusts the pressure in the adsorption tower to 0 bar (gauge pressure) in preparation for the desorption process. The depressurization process can last approximately 30 seconds.

[0067] The desorption process then proceeds. With the valve at the top of the adsorption tower closed, a vacuum pump is used to reduce the pressure. As the pressure in the adsorption tower decreases, the weakly physically bound adsorbate within the adsorbent is removed. In the desorption process, the pressure in the adsorption tower can be reduced to approximately -0.9 bar (gauge pressure) to remove the adsorbate.

[0068] Figure 4 This diagram schematically illustrates the process of a nitrogen remover 301 according to a specific embodiment of the present invention. The nitrogen remover 301 according to one embodiment removes nitrogen contained in a first generated gas and discharges a second generated gas containing hydrogen and a second tail gas. A portion of the second generated gas discharged from the nitrogen remover 301 can be supplied back to the nitrogen remover 301 as a cleaning gas and pressurizing gas, and the remainder of the second generated gas can be recovered.

[0069] When the second generated gas discharged from the nitrogen remover 301 is supplied to the nitrogen remover 301 as a cleaning gas and a pressurizing gas, the purity stability of the nitrogen remover 301 can be ensured.

[0070] The second generated gas containing hydrogen recovered from the nitrogen remover 301 can also be used for hydrogen energy, etc. The second generated gas storage tank 302 can store the recovered second generated gas.

[0071] A portion of the second generated gas stored in the second generated gas storage tank 302 can be supplied to the nitrogen remover 301 as a cleaning gas and pressurizing gas.

[0072] A portion of the second generated gas stored in the second generated gas storage tank 302 can be supplied to where it is needed, such as for use in fuel cells, petrochemical processes, ammonia synthesis, ironmaking processes, etc.

[0073] The second tail gas discharged from the nitrogen remover 301 can be supplied to the ammonia remover 201 again as a cleaning gas.

[0074] The second generated gas can contain more than 99% hydrogen by volume.

[0075] The second exhaust gas may contain 25-30% by volume hydrogen, 70-75% by volume nitrogen, and 0.5-1 ppm ammonia.

[0076] The nitrogen-containing second tail gas removed from the nitrogen remover 301 can be used to clean the ammonia remover 201. When the second tail gas is supplied to the ammonia remover 201 again as a cleaning gas, it is reused instead of being discarded. Therefore, the amount of hydrogen wasted in the hydrogen production process is reduced, thereby improving the recovery rate of the hydrogen production process.

[0077] By linking the ammonia remover and the nitrogen remover in a coordinated process, the hydrogen recovery rate and the purity of the produced hydrogen can be improved. Furthermore, by reusing raw materials and minimizing waste gas, environmental pollution generated during hydrogen production can be prevented.

[0078] The nitrogen remover 301 may include multiple adsorption towers. The nitrogen remover 301 may include an adsorbent as a substance that selectively adsorbs nitrogen. The adsorbent is not particularly limited as long as it is a substance that can selectively adsorb nitrogen, but may be, for example, at least one selected from CMS, zeolite, MOF, COF, activated carbon, alumina, silica, etc.

[0079] The nitrogen remover 301 may include: a second tail gas storage tank 303, which stores the second tail gas discharged from the nitrogen remover 301; and a second generated gas storage tank 302, which stores the second generated gas.

[0080] The nitrogen remover 301 can undergo processes of equalization, pressurization, adsorption, depressurization and desorption. Figure 6 The internal pressure changes of an adsorption tower for both ammonia and nitrogen removal are shown.

[0081] The nitrogen remover 301 may include multiple adsorption towers. In this case, the adsorption towers operate simultaneously and in conjunction. Table 3 shows the cycle of four adsorption towers according to an exemplary embodiment. One cycle has a required time of 20 minutes. The following cycle of the adsorption towers according to an exemplary embodiment is for illustrative purposes only and is not intended to limit the scope of the claims. Various changes and modifications can be made within the scope and technical concept of the invention, which will be apparent to those skilled in the art.

[0082] [Table 3] The symbols are the same as those shown in Table 2.

[0083] The pressure equalization process is the same as that described in the ammonia remover 201.

[0084] After completing the primary and secondary pressure equalization processes, a pressurization process is performed. The second generated gas discharged from the nitrogen remover 301 is used as the pressurizing gas for the nitrogen remover 301. Supplying the pressurizing gas can pressurize the pressure inside the adsorption tower from about 4 bar (gauge pressure) to about 7.5 bar (gauge pressure) in about 270 seconds.

[0085] After the pressurization process is completed, the adsorption process is carried out. The first generated gas is received from the ammonia remover 201, and nitrogen is adsorbed and removed. The adsorption time of the nitrogen remover 301 is 240-360 seconds, and the adsorption pressure can be 7-8 bar (gauge pressure). The maximum adsorption capacity of the adsorbent for ammonia and the maximum adsorption capacity for nitrogen are different. Compared with ammonia, the adsorption process for nitrogen has a relatively shorter duration.

[0086] When the adsorption time is 240-360 seconds, it has the advantage of maintaining a high nitrogen removal rate. When the adsorption time is greater than 360 seconds, the adsorption tower stops adsorbing nitrogen and discharges it, thus resulting in a decrease in the nitrogen removal rate. When the adsorption pressure is 7-8 bar (gauge pressure), it has the advantage of maximizing the nitrogen removal rate. When the adsorption pressure is less than 7 bar (gauge pressure), due to impurities, the amount of nitrogen that the adsorbent can adsorb decreases, thus resulting in the inability to remove nitrogen and its discharge.

[0087] The adsorption pressure of the nitrogen remover 301 can be lower than that of the ammonia remover 201. The pressure difference (0.1 bar (gauge pressure)) between the ammonia remover 201 and the nitrogen remover 301 can be used as the driving force for the gas. In this case, even if the ammonia remover 301 does not have a separate gas delivery device, the gas can be delivered to the nitrogen remover.

[0088] After the adsorption process is completed, a secondary pressure equalization process, a rest step, a depressurization process, and a desorption process are performed. Each process is the same as that described in ammonia remover 201. Detailed Implementation

[0089] Example The present invention will be further described below with reference to specific experimental examples. The embodiments of the present invention are not limited to the examples; high-purity hydrogen can be ensured by changing operating conditions, and the invention can adapt to variations in ammonia decomposition rate.

[0090] Ammonia is added to an ammonia decomposition reactor to obtain a mixed gas containing hydrogen, nitrogen, and unreacted ammonia. An ammonia remover consisting of four adsorption towers and a nitrogen remover consisting of four adsorption towers are used.

[0091] In the ammonia remover, after a 30-second initial pressure equalization process at 1 bar (gauge pressure), followed by a 30-second secondary pressure equalization process at 4 bar (gauge pressure), the mixed gas is then added at 20 standard liters per minute (SLPM) to the adsorption tower of the ammonia remover after a 390-second pressurization process at 7.5 bar (gauge pressure). CMS is used as the adsorbent. The adsorption process is then carried out for 420 seconds at 7.5 bar (gauge pressure), emitting a first product gas and a first tail gas containing hydrogen and nitrogen. The first product gas is then supplied to a first product gas storage tank, and the first tail gas is supplied to a first tail gas storage tank for storage. The adsorption tower is then subjected to a 30-second secondary pressure equalization process at 4 bar (gauge pressure), followed by a 360-second rest period. The adsorption tower was then subjected to a 30-second pressure equalization process at 1 bar (gauge pressure), followed by a 30-second pressure reduction process to reduce the pressure to 0 bar (gauge pressure). Finally, a 360-second desorption process was performed to reduce the pressure to -0.9 bar (gauge pressure) to remove the adsorbate. The desorption flow rate was 1.3 SLPM.

[0092] Subsequently, in the nitrogen remover, after a 30-second pressure equalization process at 1 bar (gauge pressure) and a 30-second second pressure equalization process at 4 bar (gauge pressure), the first generated gas stored in the first generated gas storage tank is added at 18.9 SLPM to the adsorption tower of the nitrogen remover after a 270-second pressurization process at 7.5 bar (gauge pressure). CMS is used as the adsorbent. Afterward, an adsorption process is performed for 300 seconds at 7.4 bar (gauge pressure) to remove nitrogen contained in the first generated gas, and a second generated gas and a second tail gas containing hydrogen are discharged. The adsorption pressure of the ammonia remover is 7.5 bar (gauge pressure), and the adsorption pressure of the nitrogen remover is 7.4 bar (gauge pressure); therefore, the pressure difference between the two processes (0.1 bar (gauge pressure)) is used as the driving force for the gas. The second generated gas is supplied to a second generated gas storage tank, and the second tail gas is supplied to a second tail gas storage tank for storage. Next, the adsorption tower underwent a secondary pressure equalization process for 30 seconds at a pressure of 4 bar (gauge pressure), followed by a 240-second rest period. Then, the adsorption tower underwent a primary pressure equalization process for 30 seconds at a pressure of 1 bar (gauge pressure), followed by a depressurization process for 30 seconds to reduce the pressure to 0 bar (gauge pressure), and finally a desorption process for 240 seconds to reduce the pressure to -0.9 bar (gauge pressure) to remove the adsorbate. The desorption flow rate was 1.0 SLPM.

[0093] Repeat the above sequence 3 times as one cycle, and repeat the cycle 10 times.

[0094] Starting from the second cycle, the first tail gas stored in the first tail gas storage tank is supplied again to the ammonia decomposition reactor as combustion gas for burning to remove unreacted ammonia, the first generated gas stored in the first generated gas storage tank is supplied again to the ammonia remover as pressurizing gas, the second tail gas stored in the second tail gas storage tank is supplied again to the ammonia remover as cleaning gas, and the second generated gas stored in the second generated gas storage tank is supplied again to the nitrogen remover as both cleaning gas and pressurizing gas.

[0095] The operating conditions for the ammonia remover and nitrogen remover are shown in Table 4.

[0096] [Table 4] The concentrations of ammonia in the first and second generated gases were measured during the process, and the results are presented. Figure 7 middle.

[0097] The concentrations of ammonia in the first generated gas, the second tail gas, and the second generated gas were measured using an Antaris IGS analyzer (analyzer model) Fourier transform infrared spectrometer (FT-IR). Peaks corresponding to the ammonia concentrations were identified, and concentration calibration curves were constructed from these peaks to analyze the ammonia concentration.

[0098] The concentration of hydrogen in the second generated gas was analyzed using an Agilent 8890GC gas chromatograph. Since high-purity hydrogen could not be directly measured, N2 and NH3, which are impurities, were analyzed, and the hydrogen concentration was calculated by relative integration.

[0099] The concentrations of each component in the first exhaust gas, and the concentrations of nitrogen and hydrogen in the first generated gas and the second exhaust gas, were analyzed using a Hiden Analytical Instruments HPR-20R&D model. This analytical method is quadrupole mass spectrometry, which allows for the detection of specific ions when substances with different voltages reach the detector. Calibration curves for each substance were then created for analysis.

[0100] It can be confirmed that the concentration of ammonia in the first generated gas after passing through the ammonia remover is approximately 0.3 ppm, which is significantly low. It can also be confirmed that the concentration of ammonia in the second generated gas after passing through the nitrogen remover is at the 0.04 ppm level, resulting in high-purity hydrogen gas that contains almost no ammonia.

[0101] After 10 cycles, the composition of the first tail gas, the first generated gas, the second tail gas, and the second generated gas is shown in Table 5.

[0102] [Table 5] The hydrogen concentration of the second generated gas was measured during the process, and the results are presented in... Figure 8 It can be confirmed that, with the coordinated operation of the ammonia remover and nitrogen remover processes, high-purity hydrogen of over 99.99% by volume can be continuously produced.

[0103] The hydrogen recovery rate is calculated using the following formula.

[0104] Hydrogen recovery rate = (H2 production rate - nitrogen remover pressurization rate - nitrogen remover cleaning rate) / H2 injection rate in the integrated process The results showed that the hydrogen recovery rate was 87.9%, which is a significantly high hydrogen recovery rate.

[0105] Explanation of reference numerals in the attached figures 101: Ammonia decomposition reactor 102: Reaction Section 103: Combustion section 104: Liquid ammonia storage tank 105: Air blower 201: Ammonia Removal Unit 202: First generated gas storage tank 203: First tail gas storage tank 301: Nitrogen Remover 302: Second generated gas storage tank 303: Second tail gas storage tank

Claims

1. A hydrogen production apparatus, comprising: An ammonia decomposition reactor that decomposes ammonia to discharge a mixture of hydrogen, nitrogen and unreacted ammonia. An ammonia remover receives the mixed gas, adsorbs and removes unreacted ammonia contained in the mixed gas, and discharges a first generated gas and a first tail gas; and A nitrogen remover receives the first generated gas, removes nitrogen contained in the first generated gas, and discharges a second generated gas and a second tail gas. The second generated gas discharged from the nitrogen remover is supplied back to the nitrogen remover as a cleaning gas and a pressurizing gas.

2. The hydrogen production apparatus according to claim 1, wherein The first tail gas discharged from the ammonia remover is supplied again to the ammonia decomposition reactor as combustion gas for burning to remove unreacted ammonia. The first generated gas discharged from the ammonia remover is supplied again to the ammonia remover as pressurizing gas. The second tail gas discharged from the nitrogen remover is supplied again to the ammonia remover as cleaning gas.

3. The hydrogen production apparatus according to claim 1, wherein The first generated gas contains 75-80% by volume hydrogen and 20-25% by volume nitrogen.

4. The hydrogen production apparatus according to claim 1, wherein The first exhaust gas contains 10-20% by volume hydrogen, 40-45% by volume nitrogen, and 40-45% by volume ammonia.

5. The hydrogen production apparatus according to claim 3, wherein The first generated gas contains 0.3-1 ppm of ammonia.

6. The hydrogen production apparatus according to claim 1, wherein The second generated gas contains more than 99% hydrogen by volume.

7. The hydrogen production apparatus according to claim 1, wherein The second exhaust gas contains 25-30% by volume hydrogen and 70-75% by volume nitrogen.

8. The hydrogen production apparatus according to claim 7, wherein The second exhaust gas contains 0.5-1 ppm of ammonia.

9. The hydrogen production apparatus according to claim 1, wherein, The ammonia remover and the nitrogen remover contain carbon molecular sieve (CMS), zeolite, metal-organic framework (MOF) or covalent organic framework (COF) as adsorbents.

10. The hydrogen production apparatus according to claim 1, wherein, The adsorption time in the ammonia remover is 360-480 seconds, and the adsorption pressure is 7-8 bar.

11. The hydrogen production apparatus according to claim 1, wherein, The adsorption time in the nitrogen remover is 240-360 seconds, and the adsorption pressure is 7-8 bar.

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