Positive pressure explosion-proof system coupled with ammonia decomposition and control method

Abstract

The invention discloses a positive pressure explosion-proof system coupled with ammonia decomposition and a control method. The system comprises an ammonia gas supply module, a positive pressure explosion-proof cabinet, a first purification module, a second purification and drying module, a palladium catalyst reactor, a purification and drying module and a nitrogen storage tank which are connected in sequence. Ammonia is catalytically decomposed into hydrogen and nitrogen mixed gas in the reactor in the explosion-proof cabinet, after purification and separation, nitrogen and residual hydrogen enter the palladium catalyst reactor to react with air to remove hydrogen, and finally high-purity nitrogen is obtained, stored and reused for maintaining the positive pressure of the explosion-proof cabinet. According to the system, comprehensive utilization of hydrogen and nitrogen in desorption gas is innovatively realized, and the pressure of the explosion-proof cabinet is accurately controlled through cooperative pressure regulation of the supercharger and the palladium catalyst reactor. By adopting a low-temperature catalyst and an optimally designed square tube type reactor structure, the device is high in heat efficiency, low in energy consumption, compact in size, safe, reliable and suitable for explosive dangerous environments.

Description

Technical Field

[0001] This invention relates to the field of explosion-proof electrical equipment technology, specifically to a positive pressure explosion-proof system and control method coupled with ammonia decomposition. Background Technology

[0002] Ammonia decomposition for hydrogen production involves high-temperature cracking of ammonia to obtain a mixture of hydrogen and nitrogen. This technology can be widely applied in industrial protective atmospheres in metallurgy, semiconductors, glass manufacturing, and other industrial gas applications. Traditional ammonia decomposition hydrogen production units place a reactor with a built-in catalyst inside an electric heating furnace, using thermal radiation to heat the reactor at high temperatures to crack ammonia and produce hydrogen. This process results in high temperatures, low thermal conductivity, and high energy consumption. Furthermore, the large size of the unit makes it difficult to meet overall explosion-proof requirements, hindering its application in hazardous environments. Existing ammonia decomposition hydrogen production equipment requires installation in a spacious, well-ventilated, independent Class A plant building, with the building designed for explosion-proof measures. This necessitates a large space volume and floor area, and strict adherence to relevant safety regulations and operating procedures is required to ensure safety. The electrical explosion-proof cabinet used in the ammonia decomposition reaction process continuously consumes high-purity nitrogen, creating an additional resource burden and waste for the system. Traditional ammonia hydrogen purification units only utilize the hydrogen from the desorbed gas, neglecting nitrogen, resulting in significant resource waste. Summary of the Invention

[0003] To address the issues of existing explosion-proof equipment used in ammonia-to-hydrogen processes being complex to operate and consuming large amounts of energy, making it difficult to accurately control the equipment to meet overall explosion-proof requirements, and resulting in significant energy consumption, this paper proposes a positive-pressure explosion-proof system coupled with ammonia decomposition. This system effectively utilizes the heat generated during system operation and accurately controls the pressure of the explosion-proof equipment, thereby improving the adaptability of ammonia-to-hydrogen units in explosive hazardous environments.

[0004] The technical solution adopted by this invention to solve its technical problem is: a positive pressure explosion-proof system coupled with ammonia decomposition, including an ammonia supply module, a positive pressure explosion-proof cabinet, a first purification module, a second purification and drying module; a palladium catalyst reactor, a purification and drying module, and a nitrogen storage tank; the ammonia supply module is connected to the ammonia inlet on the positive pressure explosion-proof cabinet and is used to supply ammonia to the inside of the positive pressure explosion-proof cabinet; an inlet valve and an exhaust valve are respectively opened on both sides of the shell of the positive pressure explosion-proof cabinet; a reactor is set in the center of the shell; the reactor includes a horizontally arranged ammonia inlet pipe, multiple vertically arranged gas channels, and a decomposition gas outlet pipe; the gas channels are rectangular tubular structures and are spaced apart from each other; one of the gas channels... One end is connected to the ammonia inlet pipe; the other end of the gas channel is connected to the decomposition gas outlet pipe; the ammonia inlet pipe is connected to the ammonia inlet; the decomposition gas outlet pipe is connected to the decomposition gas outlet; the ammonia inlet and the decomposition gas outlet extend out of the shell; the decomposition gas outlet is connected to the first purification module; the first purification module is then connected to the second purification and drying module; the second purification and drying module is connected to the palladium catalyst reactor; a booster is installed between the second purification and drying module and the palladium catalyst reactor; the palladium catalyst reactor is connected to the outside air; the palladium catalyst reactor is then connected to the nitrogen storage tank; a purification and drying module is installed between the palladium catalyst reactor and the nitrogen storage tank; the nitrogen storage tank is connected to the inside of the positive pressure explosion-proof cabinet.

[0005] Furthermore, the ammonia supply module includes a liquid ammonia tank, a liquid ammonia evaporator, an ammonia buffer tank, and a heat exchanger; the liquid ammonia tank is connected to the liquid ammonia evaporator; the liquid ammonia evaporator is then connected to the ammonia buffer tank; the ammonia buffer tank is then connected to the heat exchanger; and the heat exchanger is then connected to the positive pressure explosion-proof cabinet.

[0006] Furthermore, on the left side of the casing, near the lower surface of the casing, a first intake valve and a second intake valve are provided; the first intake valve is connected to a nitrogen source; the second intake valve is connected to a nitrogen source; an auxiliary valve is also provided in parallel above the first intake valve; a second intake valve is also provided in parallel above the first intake valve; flow meters are provided at the front end of both the first and second intake valves; the first and second intake valves are simultaneously connected to a distribution pipe inside the casing; multiple openings are provided at intervals from bottom to top on the distribution pipe; the multiple openings are evenly distributed along the length of the distribution pipe; on the right side of the casing, near the upper part of the casing, a heat exchange exhaust valve and a heat dissipation exhaust valve are provided; the heat exchange exhaust valve and the heat dissipation exhaust valve are arranged in parallel, one above the other.

[0007] Furthermore, the reactor includes an ammonia inlet, a decomposition gas outlet, multiple gas channels, an ammonia inlet pipe, and a decomposition gas outlet pipe; the ammonia inlet pipe is located at the top of the reactor and is horizontally arranged; the decomposition gas outlet pipe is located at the bottom of the reactor and is horizontally arranged; multiple gas channels are located between the ammonia inlet pipe and the decomposition gas outlet pipe; the ammonia inlet pipe is connected to the ammonia inlet; the ammonia inlet pipe is divided into a first inlet section and a second inlet section; the volume of the first inlet section is smaller than that of the second inlet section; the first inlet section is connected to the ammonia inlet; the first inlet section is simultaneously connected to one end of multiple gas channels; the decomposition gas outlet pipe is divided into a first outlet pipe and a second outlet pipe with different volumes; the volume of the first outlet pipe is... The volume is greater than that of the second discharge pipe; the other end of the gas channel connected to the first inlet is also connected to the first discharge pipe; the first discharge pipe is also connected to one end of multiple other gas channels; the other ends of multiple other gas channels are connected to the second inlet; the second inlet is then connected to the remaining gas channels; the other end of the remaining gas channels is then connected to the second discharge pipe; the second discharge pipe is connected to the decomposed gas outlet; multiple gas channels are spaced apart; multiple electric heating elements are installed in the gap between two adjacent gas channels; the electric heating elements are installed close to the gas channels; multiple electric heating elements located between two adjacent gas channels are spaced apart from each other; each electric heating element extends into the interior of the housing.

[0008] Furthermore, the gas channel is a hollow rectangular structure; the total volume of the solid part of the gas channel is greater than the total volume of the hollow part of the gas channel; the hollow part of the gas channel is filled with an ammonia decomposition catalyst; the ammonia decomposition catalyst is a ruthenium-based catalyst.

[0009] Furthermore, a control box is provided on the side of the housing; a temperature sensor and a pressure sensor are provided inside the housing; the control box is electrically connected to the first intake valve, the second intake valve, the ventilation exhaust valve, the heat dissipation exhaust valve, the temperature sensor, the pressure sensor, and multiple electric heating elements.

[0010] Furthermore, the positive pressure explosion-proof cabinet is connected to the heat exchanger; the heat exchanger is connected to the first purification module; the first purification module includes a water cooler, a TSA purification device, and a first buffer tank; the water cooler, the TSA purification device, and the first buffer tank are connected in series sequentially; the heat exchanger is connected to the water cooler; the second purification and drying module includes a hydrogen-nitrogen compressor, a second buffer tank, and a PSA purification device; the hydrogen-nitrogen compressor, the second buffer tank, and the PSA purification device are connected in series sequentially; the hydrogen-nitrogen compressor is also connected to the first buffer tank; the PSA purification device is connected to the booster compressor.

[0011] Furthermore, the purification and drying module includes a condenser, a dryer, and a water tank connected in sequence; the condenser is connected to the dryer; the dryer is connected to the nitrogen storage tank; the gas outlet of the palladium catalyst reactor is connected to the condenser; the nitrogen storage tank is then connected to the positive pressure explosion-proof cabinet, the dryer, and the TSA purification device; the condenser is circulated to the water tank; the cooling water in the water tank circulates between the water tank and the condenser; the water tank is also connected to the hydrogen-nitrogen compressor and the water cooler respectively; the water cooler is then connected to the liquid ammonia evaporator; the liquid water in the water tank can circulate between the water tank and the hydrogen-nitrogen compressor; the liquid water in the water tank can circulate between the water tank and the liquid ammonia evaporator and the water cooler.

[0012] A control method for a positive pressure explosion-proof system using coupled ammonia decomposition includes the following steps: Step 1: Evaporating liquid ammonia into ammonia gas and introducing the evaporated ammonia gas into a reactor in a positive pressure explosion-proof cabinet; Step 2: Controlling the reactor to decompose the ammonia gas into a hydrogen-nitrogen mixture; passing the hydrogen-nitrogen mixture sequentially through a first purification device and a second purification device; respectively completing the adsorption and removal of ammonia gas and the separation of hydrogen and nitrogen gas; Step 3: Adjusting the internal pressure of the second purification device and introducing the desorbed nitrogen gas and a small amount of hydrogen gas into a palladium catalyst reactor through a booster compressor; introducing air into the palladium catalyst reactor; controlling the palladium catalyst reactor to react hydrogen and oxygen to generate water vapor; Step 4: [The text abruptly ends here, likely due to an incomplete translation or missing information.] Nitrogen and water vapor are discharged and introduced into the purification and drying module for cooling and drying; nitrogen is obtained; the nitrogen is then introduced into a nitrogen storage tank for storage; Step 5: The nitrogen in the nitrogen storage tank is introduced into the positive pressure explosion-proof cabinet; the pressure in the positive pressure explosion-proof cabinet is detected; when the pressure is less than the lower limit of the positive pressure explosion-proof cabinet; first increase the power of the booster or increase the gas flow rate into the palladium catalyst reactor, and then increase the opening of the inlet valve and decrease the opening of the exhaust valve; when the pressure is greater than the upper limit of the positive pressure explosion-proof cabinet; first decrease the power of the booster or decrease the gas flow rate into the palladium catalyst reactor, and then increase the opening of the exhaust valve and decrease the opening of the inlet valve; until the internal pressure of the positive pressure explosion-proof cabinet stabilizes within the preset pressure range.

[0013] Furthermore, in step five, first increase the power of the booster or increase the gas flow rate into the palladium catalyst reactor, and introduce nitrogen into the positive pressure explosion-proof cabinet by opening the inlet valve to continuously fill the positive pressure explosion-proof cabinet with nitrogen; monitor the pressure in the positive pressure explosion-proof cabinet; make the pressure in the positive pressure explosion-proof cabinet reach the upper limit; when the pressure in the positive pressure explosion-proof cabinet reaches the upper limit; first reduce the power of the booster or reduce the gas flow rate into the palladium catalyst reactor, and then open the exhaust valve to depressurize the inside of the positive pressure explosion-proof cabinet and monitor the pressure in the positive pressure explosion-proof cabinet; when the pressure in the positive pressure explosion-proof cabinet reaches the lower limit, increase the opening of the inlet valve to introduce nitrogen into the positive pressure explosion-proof cabinet, and continue to monitor the pressure in the positive pressure explosion-proof cabinet; when the pressure in the positive pressure explosion-proof cabinet is detected to be greater than the upper limit for more than 30 seconds; or the pressure in the positive pressure explosion-proof cabinet is detected to be less than the lower limit for more than 10 seconds; immediately stop heating the ammonia in the reactor.

[0014] The positive pressure explosion-proof system and control method coupled with ammonia decomposition described in this invention have the following advantages:

[0015] 1) Effectively solves the problem of efficient utilization of desorption gas in the ammonia-to-hydrogen purification process. Innovatively, it proposes a comprehensive utilization scheme of hydrogen and nitrogen, which not only utilizes the heat generated by the reaction of hydrogen and oxygen, but also recovers and utilizes the nitrogen in it, thus achieving efficient resource recovery and utilization. It also provides a continuous nitrogen source for the explosion-proof system of the system, and can be output for use.

[0016] 2) By utilizing the combined effects of booster pressurization and palladium tactile reaction, the exhaust gas pressure is increased (e.g., 10-50 kPa) and precisely adapted to the downstream operating pressure requirements. Considering the pressure drop along the process, the pressure reaching the nitrogen storage tank and the positive pressure explosion-proof cabinet is within the operating range of the explosion-proof cabinet, and the operating pressure can be adjusted more precisely within a smaller range, such as 1000-1100 Pa. Compared with the traditional manual pressure adjustment mode, this system adjusts pressure more accurately.

[0017] 3) The reactor in the positive pressure explosion-proof cabinet uses a new type of low-temperature catalyst, which greatly reduces the ammonia cracking temperature. The reactor structure is also optimized, using parallel square tubes that can directly contact the heating elements. This not only reduces the reactor volume but also changes the traditional electric furnace thermal radiation heating scheme, using direct contact heat conduction to improve heat transfer efficiency and reduce overall energy consumption. This provides a solution for using ammonia decomposition hydrogen production equipment in explosive hazardous environments. It has low operating temperature, low energy consumption, compact equipment, relatively relaxed installation conditions, simple operation, excellent protection effect, and high reliability. Due to its low operating temperature and small size, it can be installed in a positive pressure explosion-proof protective device, effectively solving the safety problems of traditional ammonia hydrogen production equipment in explosive hazardous environments. Its equipment is compact, easy to operate, safe and reliable, and suitable for indoor and outdoor Zone I and Zone II explosive hazardous environments. This technology can be applied to industrial protective gas stations, hydrogen refueling stations, and other industrial sites. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the specific embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of a positive pressure explosion-proof system coupled with ammonia decomposition according to the present invention;

[0020] Figure 2 This is a schematic diagram of the internal structure of a positive pressure explosion-proof cabinet of a positive pressure explosion-proof system coupled with ammonia decomposition as described in this invention.

[0021] Figure 3 This is a cross-sectional view of the internal structure of a positive pressure explosion-proof cabinet of a positive pressure explosion-proof system coupled with ammonia decomposition as described in this invention.

[0022] Figure 4 This is a schematic diagram of the positive pressure explosion-proof cabinet of the positive pressure explosion-proof system coupled with ammonia decomposition described in this invention from another angle. Detailed Implementation

[0023] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] like Figures 1-4 As shown, the positive pressure explosion-proof system coupled with ammonia decomposition according to the present invention includes an ammonia supply module 1, a positive pressure explosion-proof cabinet 2, a first purification module 3, a second purification module 4; a palladium catalyst reactor 6, a purification and drying module 7, and a nitrogen storage tank 9;

[0025] The ammonia supply module 1 is connected to the ammonia inlet 221 on the positive pressure explosion-proof cabinet 2 and is used to supply ammonia to the inside of the positive pressure explosion-proof cabinet 2.

[0026] The positive pressure explosion-proof cabinet 2 has an inlet valve and an exhaust valve on both sides of its shell 21. A control box is fixed on the side wall of the shell 21. A reactor 22 is located at the center of the shell 21. The reactor 22 includes a horizontally arranged ammonia gas inlet pipe 225, multiple vertically arranged gas channels 223, and a decomposition gas outlet pipe 226. The gas channels 223 are rectangular tubular structures and are spaced apart from each other. One end of the gas channel 223 is connected to the ammonia gas inlet pipe 225. The other end of the gas channel 223 is connected to the decomposition gas outlet pipe 226. The ammonia gas inlet pipe 225 is connected to the ammonia gas inlet 221. The decomposition gas outlet pipe 226 is connected to the decomposition gas outlet 222. The ammonia gas inlet 221 and the decomposition gas outlet 222 extend out of the shell 21.

[0027] The decomposed gas outlet 222 is connected to the first purification module 3; the first purification module 3 is then connected to the second purification module 4; the second purification module 4 is connected to the palladium catalyst reactor 6; a booster 5 is provided between the second purification module 4 and the palladium catalyst reactor 6; the palladium catalyst reactor 6 is connected to the outside air; the palladium catalyst reactor 6 is then connected to the nitrogen storage tank 9; the purification and drying module 7 is provided between the palladium catalyst reactor 6 and the nitrogen storage tank 9; the nitrogen storage tank 9 is internally connected to the positive pressure explosion-proof cabinet 2.

[0028] exist Figure 1 In this system, the ammonia supply module 1 includes a liquid ammonia tank 11, a liquid ammonia evaporator 12, an ammonia buffer tank 13, and a heat exchanger 14. The liquid ammonia tank 11 is connected to the liquid ammonia evaporator 12. The liquid ammonia evaporator 12 is then connected to the ammonia buffer tank 13. The ammonia buffer tank 13 is then connected to the heat exchanger 14. The heat exchanger 14 is then connected to the positive pressure explosion-proof cabinet. The liquid ammonia discharged from the liquid ammonia tank 11 first enters the liquid ammonia evaporator 12 for heating and evaporation to form ammonia gas. The evaporated ammonia gas enters the ammonia buffer tank 13 for buffering and pressure regulation. Then it enters the heat exchanger 14 to exchange heat with a heat source, and after heat exchange, it enters the positive pressure explosion-proof cabinet 2 for ammonia decomposition reaction.

[0029] The positive pressure explosion-proof cabinet 2 has a reactor 22 inside its shell 21. The reactor 22 is fixed to the lower surface of the shell 21 and has a gap between the inner wall of the shell 21. A first air inlet valve V1 and a second air inlet valve V2 are provided on the left side of the shell 21, near the lower surface. The first air inlet valve V1 is connected to a nitrogen source, and the second air inlet valve V2 is also connected to a nitrogen source. By adjusting the opening of the first air inlet valve V1 and the second air inlet valve V2, the volume of nitrogen entering the shell 21 is controlled, thereby controlling the pressure inside the shell 21. Preferably, an auxiliary valve is also connected in parallel above the first air inlet valve V1. The first air inlet valve V1 serves as the main control valve for introducing nitrogen into the shell 21. Combined with the auxiliary valve connected in parallel above the first air inlet valve V1, this improves the stability of nitrogen supply to the shell 21 and avoids... This design addresses two main issues: firstly, it overcomes the limitation of uncontrollable nitrogen flow when the valve is damaged; secondly, it improves the versatility of pressure adjustment for the gas introduced into the housing 21; by separately controlling the first inlet valve V1 and the auxiliary valve, the gas flow path into the housing 21 is adjusted, thereby controlling the pressure of nitrogen entering the housing 21 and achieving flexible pressure control within the housing 21; specifically, to further improve pressure control within the housing 21 and increase the pressure control range, a second inlet valve V2 is connected in parallel above the first inlet valve V1; by adjusting the second inlet valve V2, nitrogen entering the housing 21 is replenished, thereby increasing the pressure inside the housing 21; flow meters are installed at the front ends of both the first inlet valve V1 and the second inlet valve V2 to monitor the nitrogen pressure entering the housing 21 through the first inlet valve V1 and the second inlet valve V2.

[0030] This system uses nitrogen as the protective gas, requiring a clean and dry gas source with a nitrogen purity ≥95%. To ensure gas source reliability, the system employs a dual gas source supply. During normal operation, the main gas source (i.e., gas intake through the first inlet valve V1) is used. When the main gas source fails, the backup gas source (intake through the second inlet valve V2) can continue to maintain the pressure and flow required for positive pressure operation within the cabinet, ensuring the reactor can cool down and shut down normally. The backup gas source can be supplied by an independent nitrogen generator or nitrogen cylinder, with a pressure ≥0.1MPa and a flow rate ≥100L / min (maximum leakage flow rate of the positive pressure cabinet). The shell 21 is made of stainless steel or carbon steel, with a thickness ≥1.5mm, pressure resistance ≥2kPa, protection level IP65, and maximum leakage flow rate ≤100L / min.

[0031] like Figures 2-4As shown, the reactor 22 includes an ammonia inlet 221, a decomposition gas outlet 222, multiple gas channels 223, an ammonia inlet pipe 225, and a decomposition gas outlet pipe 226. The ammonia inlet pipe 225 is located at the upper part of the reactor 22 and is horizontally arranged. The decomposition gas outlet pipe 226 is located at the lower part of the reactor 22 and is horizontally arranged. The multiple gas channels 223 are all located between the ammonia inlet pipe 225 and the decomposition gas outlet pipe 226. The ammonia inlet pipe 225 is connected to the ammonia inlet 221. The ammonia inlet pipe 225 is divided into a first inlet section and a second inlet section. The volume of the first inlet section is smaller than that of the second inlet section. The first inlet section is connected to the ammonia inlet 221. The first inlet section is connected to the three gas channels 223. One end of 3 is simultaneously connected; wherein, the decomposition gas discharge pipe 226 is divided into a first discharge pipe and a second discharge pipe with different volumes; the volume of the first discharge pipe is larger than the volume of the second discharge pipe; the other ends of the three gas channels 223 connected to the first inlet are simultaneously connected to the first discharge pipe; the first discharge pipe is also simultaneously connected to one end of the other four gas channels 223; the other ends of the other four gas channels 223 are simultaneously connected to the second inlet; the second inlet is then connected to the remaining three gas channels 223; the other ends of the remaining three gas channels 223 are then connected to the second discharge pipe; the second discharge pipe is connected to the decomposition gas outlet 222; the ammonia inlet 221 is connected to the heat exchanger 14.

[0032] After heat exchange, the ammonia gas enters the first inlet section through the ammonia inlet 221. The ammonia gas is then diverted through the first inlet section into three gas channels 223 and flows along the installation direction of the gas channels 223 towards the direction of approaching the first outlet pipe. After entering the first outlet pipe, the gas continues to collect inside the first outlet pipe and is diverted into four other gas channels 223. The diverted gas then flows towards the direction of approaching the second inlet section in these four gas channels 223 and enters the second inlet section. Subsequently, it further collects in the second inlet section and continues to be diverted into the remaining three gas channels 223. Finally, the gas flows towards the direction of approaching the second outlet pipe in the last three gas channels 223 and collects into the second outlet pipe. Finally, the gas is discharged through the decomposed gas outlet 223 on the second discharge pipe; wherein, the plurality of gas channels 223 are arranged parallel to each other and spaced apart from each other; the installation direction of the gas channels 223 is perpendicular to the installation direction of the ammonia inlet pipe 225 and the decomposed gas outlet pipe 226; when ammonia enters the first inlet section, the ammonia is then diverted to three of the gas channels 223, and enters the first discharge section through the three gas channels 223; in the first discharge section, it is diverted to four other gas channels 223 and flows along the flow direction of these four gas channels 223, entering the second inlet section; in the second inlet section, it is diverted to the remaining three gas channels 223, and finally enters the second discharge section; and then is discharged through the decomposed gas outlet 222.

[0033] Therefore, the gas flows vertically between the ammonia inlet pipe 225 and the decomposition gas outlet pipe 226. Compared to a straight flow, this extends the ammonia flow distance, increases the heating time, and promotes the complete endothermic decomposition of ammonia. Multiple electric heating elements 224 are installed in the gap between adjacent gas channels 223. These elements use nickel-chromium alloy heating wires, are insulated with ceramic, and protected by an outer metal shell, and are installed close to the gas channel. The multiple electric heating elements 224 located between adjacent gas channels 223 are spaced apart. Each electric heating element 224 extends into the housing 21. Each gas channel 223 is a hollow rectangular structure. The total volume of the solid portion of each gas channel 223 is greater than the total volume of the hollow portion. The hollow portion of the gas channel 223 is used for ammonia flow. The hollow portion of the gas channel 223 is filled with an ammonia decomposition catalyst, such as a ruthenium-based catalyst, to improve ammonia decomposition efficiency. Ammonia flows through the multiple gas channels 225. During flow, under the catalytic action of the ammonia decomposition catalyst filled in its hollow part and the heating action of the electric heating element 224, the ammonia is decomposed into a mixed gas of hydrogen and nitrogen through endothermic decomposition. By adopting a rectangular gas channel with multiple gas channels arranged in parallel, it can directly contact the heating element, which not only reduces the reactor volume and improves the compactness between multiple gas channels, but also changes the traditional electric furnace thermal radiation heating scheme. Heating is carried out through direct contact heat conduction, which improves heat transfer efficiency and reduces overall energy consumption. Similarly, by increasing the total volume of the solid part in the gas pipeline, the high pressure resistance of the gas pipeline is improved, which compensates for the reduced pressure resistance caused by the use of a rectangular gas channel structure to improve space utilization. The pressure adaptability of reactor 22 inside shell 21 is improved. The gas channels of the reactor are made of stainless steel metal material, and all connection points of the reactor are welded with stainless steel welding wire. The reactor is a closed container, and it only needs to be heated to about 500°C to catalytically crack ammonia to produce hydrogen during normal operation. Compared with traditional reactors, it has the characteristics of low temperature, low energy consumption, and small size.

[0034] The first intake valve V1 and the second intake valve V2 are simultaneously connected to the diversion pipe 23 inside the housing 21. The diversion pipe 23 has multiple openings spaced apart from bottom to top. These openings are evenly distributed along the length of the diversion pipe 23. Nitrogen gas introduced through the first intake valve V1 or the second intake valve V2 first gathers and enters the diversion pipe 23. It flows upwards along the installation direction of the diversion pipe 23 and exits through the spaced openings, entering the interior of the housing 21. This achieves uniform inflation of all parts inside the housing 21, improving the pressure distribution uniformity within the housing 21. A heat exchange exhaust valve V3 and a heat dissipation exhaust valve V4 are located on the right side of the housing 21 near the upper part. The heat exchange exhaust valve V3 and the heat dissipation exhaust valve V4 are arranged vertically in parallel. The ventilation exhaust valve V3 and the heat dissipation exhaust valve V4 are both used to discharge nitrogen gas inside the housing 21 and reduce the pressure inside the housing 21. The ventilation exhaust valve V3 is mainly used to discharge gas from inside the housing 21. When the temperature inside the housing 21 becomes too high due to heating ammonia gas, the heat dissipation exhaust valve V4 is opened to further discharge the overheated nitrogen gas from the housing 21, preventing excessive pressure inside the housing 21. By positioning the heat dissipation exhaust valve V4 and the ventilation exhaust valve V3 diagonally opposite the first intake valve V1 and the second intake valve V2, nitrogen gas is evenly filled inside the housing 21, preventing localized high or low pressure situations. Combined with the vertically arranged ventilation exhaust valve V3 and heat dissipation exhaust valve V4, the pressure inside the housing 21 is slowly and steadily released, allowing for stable and accurate control of the pressure inside the housing 21.

[0035] Furthermore, a control box V6 is also provided on the side of the housing 21; a temperature sensor and a pressure sensor are provided inside the housing 21; the control box V6 is electrically connected to the first intake valve V1, the second intake valve V2, the ventilation exhaust valve V3, the heat dissipation exhaust valve V4, the temperature sensor, the pressure sensor, and multiple electric heating elements 224; the temperature sensor is a thermocouple, which is used as a temperature acquisition instrument to collect the temperature of the heating elements, the reactor bed, and the positive pressure cabinet, that is, as a reactor heating temperature control instrument, and also interlocks to stop heating the reactor when the temperature of the heating elements / bed / positive pressure cabinet exceeds the set temperature, protecting the equipment to operate within the normal range; through the control box V6, based on the display data of the pressure sensor and the temperature sensor, the first intake valve V1, the second intake valve V2, the ventilation exhaust valve V3, the heat dissipation exhaust valve V4, and the multiple electric heating elements 224 are controlled accordingly; improving the system control efficiency and pressure regulation accuracy.

[0036] exist Figure 1In this process, the decomposition gas outlet 222 is connected to the heat exchanger 14; the hydrogen-nitrogen mixture discharged from the decomposition gas outlet 222 serves as the heat source for the heat exchanger 14 and exchanges heat with the ammonia discharged from the ammonia buffer tank 13; the cooled hydrogen-nitrogen mixture after heat exchange enters the first purification module 3 for preliminary adsorption and purification; the first purification module 3 includes a water cooler 31, a TSA purification device 32, and a first buffer tank 33; the water cooler 31, the TSA purification device 32, and the first buffer tank 33 are connected in series; the water cooler 31 is used to further cool the hydrogen-nitrogen mixture to meet the temperature requirements of subsequent purification processes; the hydrogen-nitrogen mixture cooled by the water cooler 31 enters the TSA purification device 32 for further purification; removing the small amount of unreacted ammonia remaining in the hydrogen-nitrogen mixture; the purified hydrogen-nitrogen mixture is discharged from the TSA purification device 32 and then enters the first buffer tank 33 for buffer storage and gas pressure adjustment; the first buffer tank 33 is connected to the second purification module 4.

[0037] The second purification module 4 includes a hydrogen-nitrogen compressor 41, a second buffer tank 42, and a PSA purification device 43. The hydrogen-nitrogen compressor 41 is connected in series with the second buffer tank 42 and the PSA purification device 43. The hydrogen-nitrogen compressor 41 is also connected to the first buffer tank 33. The hydrogen-nitrogen mixture discharged from the first buffer tank 33, after pressure adjustment, is further compressed by the hydrogen-nitrogen compressor 41 to suit subsequent PSA purification. The compressed hydrogen-nitrogen mixture enters the second buffer tank 42 for pressure adjustment. After being discharged from the second buffer tank 42, it enters the PSA purification device 43 for pressure swing adsorption. By adjusting the internal pressure, the hydrogen-nitrogen mixture is purified according to the yield of the adsorption column inside the PSA purification device 43. Nitrogen in the combined gas is adsorbed, achieving separation of hydrogen and nitrogen. The separated hydrogen is discharged from the PSA purification device 43 and stored and collected. During depressurization desorption of the PSA purification device, the desorbed gas (including nitrogen and a small amount of hydrogen) in the adsorption column due to the pressure reduction is discharged from the PSA purification device 43 and enters the booster 5, and then enters the palladium catalyst reactor 6 for further reaction. The booster 5 is used to introduce the desorbed gas into the palladium catalyst reactor 6 and increase the pressure of the desorbed gas. By adjusting the power of the booster 5, the pressure entering the palladium catalyst reactor 6 is controlled accordingly, improving the controllability of the pressure of nitrogen entering the nitrogen storage tank 9 and the positive pressure explosion-proof cabinet 2, thereby improving the pressure stability in the positive pressure explosion-proof cabinet 2.

[0038] Nitrogen and a small amount of hydrogen desorbed from the PSA purification device 43 enter the palladium catalyst reactor 6. The palladium catalyst reactor 6 is also connected to the external air. Inside the palladium catalyst reactor 6, nitrogen, hydrogen, and oxygen from the air contact the palladium metal membrane. Under the catalytic action of the palladium metal, hydrogen and oxygen react on the surface of the palladium metal membrane to generate water molecules and release a large amount of heat. The amount of dry air is adjusted so that the hydrogen in the desorbed gas reacts completely with the oxygen. The gas after the palladium catalyst reaction is mainly nitrogen (containing water, and small amounts of O2, CO2, and rare gases, etc.). This achieves the removal of hydrogen from the mixed gas, completing the purification of the nitrogen for subsequent positive pressure maintenance and pressure adjustment inside the positive pressure explosion-proof cabinet 2, realizing the effective application of the nitrogen generated by the ammonia decomposition reaction. Preferably, the palladium catalyst reactor 6 is thermally connected to the heat storage device 8. The heat generated by the reaction of hydrogen and oxygen is carried away and stored through the heat storage device and then output for utilization, for example, as heating during the desorption process of purification devices such as TSA.

[0039] The gas outlet of the palladium catalyst reactor 6 is connected to the purification and drying module 7. The purification and drying module 7 includes a condenser 71, a dryer 72, and a water tank 73 connected in sequence. The condenser 71 is connected to the dryer 72. The dryer 72 is connected to the nitrogen storage tank 9. The mixed gas of nitrogen, water vapor, and a small amount of carbon dioxide discharged after the reaction in the palladium catalyst reactor 6 first enters the condenser 71 for cooling. The nitrogen is cooled to room temperature. At the same time, the water vapor is cooled into liquid water and the liquid water is separated from the nitrogen. After separation, the mixed gas of nitrogen and carbon dioxide enters the dryer 72 for drying and purification. The carbon dioxide, residual water vapor, oxygen, etc. are adsorbed and removed. The resulting high-purity nitrogen enters the nitrogen storage tank for storage and provides a stable nitrogen source for the positive pressure explosion-proof cabinet. It can also provide a nitrogen source for the desorption process of the purification dryer and TSA purification device; the purified nitrogen enters the nitrogen storage tank 9 for storage; the nitrogen storage tank 9 is then connected to the first inlet valve V1 of the positive pressure explosion-proof cabinet 2; used to maintain the positive pressure inside the positive pressure explosion-proof cabinet 2; improving the explosion-proof effect of the positive pressure explosion-proof cabinet 2; preferably, the nitrogen storage tank 9 is also connected to the dryer 72 and the TSA purification device 32 respectively; for the desorption process of the dryer 72 and the TSA purification device 32 respectively. The process provides a nitrogen source; the condenser 71 is connected to the water tank 73; the cooling water in the water tank 73 circulates between the water tank 73 and the condenser 71; the liquid water cooled and separated in the condenser 71 is promptly discharged and returned to the water tank 73; more preferably, the water tank 73 is also connected to the hydrogen-nitrogen compressor 41 and the water cooler 31 respectively; the water cooler 31 is then connected to the liquid ammonia evaporator 12; the liquid water in the water tank 73 can also be... The liquid water circulates between the water tank 73 and the hydrogen-nitrogen compressor 41; it continuously provides cooling water to the hydrogen-nitrogen compressor 41 and promptly discharges any remaining liquid water produced after compression; the liquid water in the water tank 73 can also circulate between the water tank 73, the liquid ammonia evaporator 12, and the water cooler 31; the liquid water in the water tank first enters the water cooler 31 and is used to cool the hydrogen-nitrogen mixture; the heated liquid water is discharged from the water cooler 31 and enters the liquid ammonia evaporator 12 to utilize the absorbed heat. The liquid ammonia is vaporized and evaporated into ammonia gas; liquid water is continuously supplied to the water cooler 31 for cooling the hydrogen-nitrogen mixture, and liquid water is continuously supplied to the liquid ammonia evaporator 12 for heat exchange with liquid ammonia to vaporize the liquid ammonia into ammonia gas; the circulation of liquid water between the condenser 71, water tank 73, hydrogen-nitrogen compressor 41, water cooler 31 and liquid ammonia evaporator 12 is realized; the liquid water is effectively utilized while the coordinated operation between the components is realized; the overall control efficiency of the components is improved.

[0040] This application also discloses a control method for a positive pressure explosion-proof system coupled with ammonia decomposition; including the following steps:

[0041] Step 1: Evaporate liquid ammonia into ammonia gas and introduce the evaporated ammonia gas into the reactor in the positive pressure explosion-proof cabinet;

[0042] Step 2: Control the reactor to decompose ammonia into a hydrogen-nitrogen mixture; pass the hydrogen-nitrogen mixture sequentially through the first purification device and the second purification device; respectively complete the adsorption and removal of ammonia and the separation of hydrogen and nitrogen.

[0043] Step 3: Adjust the internal pressure of the second purification unit and introduce the desorbed nitrogen and a small amount of hydrogen into the palladium catalyst reactor through a booster compressor; introduce air into the palladium catalyst reactor; control the palladium catalyst reactor to react hydrogen and oxygen to generate water vapor; complete the removal of hydrogen.

[0044] Step 4: The nitrogen and water vapor in the palladium catalyst reactor are discharged and introduced into the purification and drying module for cooling and drying; nitrogen is obtained; the nitrogen is then introduced into a nitrogen storage tank for storage.

[0045] Step 5: Introduce nitrogen from the nitrogen storage tank into the positive pressure explosion-proof cabinet; check the pressure inside the positive pressure explosion-proof cabinet; when the pressure is lower than the lower limit of the positive pressure explosion-proof cabinet; first increase the power of the booster or increase the gas flow rate into the palladium catalyst reactor, then increase the opening of the inlet valve and decrease the opening of the exhaust valve; when the pressure is higher than the upper limit of the positive pressure explosion-proof cabinet; first reduce the power of the booster or reduce the gas flow rate into the palladium catalyst reactor, then increase the opening of the exhaust valve and decrease the opening of the inlet valve; until the internal pressure of the positive pressure explosion-proof cabinet stabilizes within the preset pressure range.

[0046] In step five, first increase the power of the booster or increase the gas flow rate into the palladium catalyst reactor. Nitrogen is introduced into the positive pressure explosion-proof cabinet by opening the inlet valve, continuously filling the cabinet with nitrogen. The pressure inside the cabinet is monitored until it reaches its upper limit. When the pressure reaches its upper limit, the booster power is reduced or the gas flow rate into the palladium catalyst reactor is decreased. Then, the exhaust valve is opened to depressurize the inside of the cabinet, and the pressure is monitored again. When the pressure inside the cabinet reaches its lower limit, the opening of the inlet valve is increased to allow nitrogen to flow into the cabinet, and the pressure is monitored again. This process is repeated until the pressure inside the cabinet stabilizes within the specified range. If the pressure inside the cabinet remains above the upper limit for more than 30 seconds, or remains below the lower limit for more than 10 seconds, the heating of the reactor is immediately disconnected.

[0047] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A positive pressure explosion-proof system coupled with ammonia decomposition, comprising an ammonia supply module, a positive pressure explosion-proof cabinet, a first purification module, a second purification and drying module; a palladium catalyst reactor, the purification and drying module, and a nitrogen storage tank; characterized in that: The ammonia supply module is connected to the ammonia inlet on the positive pressure explosion-proof cabinet and is used to supply ammonia to the inside of the positive pressure explosion-proof cabinet. The positive pressure explosion-proof cabinet has an inlet valve and an exhaust valve on both sides of its shell. A reactor is located at the center of the shell. The reactor includes a horizontally arranged ammonia inlet pipe, multiple vertically arranged gas channels, and a decomposition gas outlet pipe. The gas channels are rectangular tubular structures spaced apart from each other. One end of each gas channel is connected to the ammonia inlet pipe, and the other end is connected to the decomposition gas outlet pipe. The ammonia inlet pipe is connected to the ammonia inlet. The decomposition gas outlet pipe is connected to the decomposition gas outlet. The ammonia inlet and the decomposition gas outlet extend out of the shell. The decomposed gas outlet is connected to the first purification module; the first purification module is then connected to the second purification and drying module; the second purification and drying module is connected to the palladium catalyst reactor; a booster compressor is installed between the second purification and drying module and the palladium catalyst reactor; the palladium catalyst reactor is connected to the outside air; the palladium catalyst reactor is then connected to the nitrogen storage tank; the purification and drying module is installed between the palladium catalyst reactor and the nitrogen storage tank; the nitrogen storage tank is internally connected to the positive pressure explosion-proof cabinet.

2. The positive pressure explosion-proof system coupled with ammonia decomposition according to claim 1, characterized in that: The ammonia supply module includes a liquid ammonia tank, a liquid ammonia evaporator, an ammonia buffer tank, and a heat exchanger; the liquid ammonia tank is connected to the liquid ammonia evaporator; the liquid ammonia evaporator is then connected to the ammonia buffer tank; the ammonia buffer tank is then connected to the heat exchanger; and the heat exchanger is then connected to the positive pressure explosion-proof cabinet.

3. The positive pressure explosion-proof system coupled with ammonia decomposition according to claim 1, characterized in that: On the left side of the housing, near the lower surface of the housing, a first air inlet valve and a second air inlet valve are provided; the first air inlet valve is connected to a nitrogen source; the second air inlet valve is connected to a nitrogen source; an auxiliary valve is also provided in parallel above the first air inlet valve; the second air inlet valve is also provided in parallel above the first air inlet valve; a flow meter is provided at the front end of both the first air inlet valve and the front end of the second air inlet valve; the first air inlet valve and the second air inlet valve are simultaneously connected to a diversion pipe inside the housing; the diversion pipe has multiple openings spaced apart from bottom to top; Multiple openings are evenly distributed along the length of the diversion pipe; a ventilation exhaust valve and a heat dissipation exhaust valve are provided on the right side of the housing near the upper part of the housing; the heat exchange exhaust valve and the heat dissipation exhaust valve are arranged in parallel, one above the other.

4. The positive pressure explosion-proof system coupled with ammonia decomposition according to claim 3, characterized in that: The reactor includes an ammonia inlet, a decomposition gas outlet, multiple gas channels, an ammonia inlet pipe, and a decomposition gas outlet pipe. The ammonia inlet pipe is located at the top of the reactor and is horizontally arranged. The decomposition gas outlet pipe is located at the bottom of the reactor and is horizontally arranged. The multiple gas channels are all located between the ammonia inlet pipe and the decomposition gas outlet pipe. The ammonia inlet pipe is connected to the ammonia inlet. The ammonia gas inlet pipeline is divided into a first inlet section and a second inlet section. The volume of the first introduced portion is smaller than that of the second introduced portion; The first inlet portion is connected to the ammonia inlet; the first inlet portion is simultaneously connected to one end of multiple gas channels; the decomposition gas discharge pipe is divided into a first discharge pipe and a second discharge pipe with different volumes; the volume of the first discharge pipe is larger than the volume of the second discharge pipe; the other end of the gas channel connected to the first inlet portion is simultaneously connected to the first discharge pipe; the first discharge pipe is also simultaneously connected to one end of multiple other gas channels; the other end of multiple other gas channels is simultaneously connected to the second inlet portion; the second inlet portion is then connected to the remaining gas channels; the other end of the remaining gas channels is then connected to the second discharge pipe; the second discharge pipe is connected to the decomposition gas outlet; multiple gas channels are spaced apart; multiple electric heating elements are arranged in the gap between two adjacent gas channels; the electric heating elements are installed close to the gas channels; multiple electric heating elements located between two adjacent gas channels are spaced apart from each other; each electric heating element extends into the interior of the housing.

5. The positive pressure explosion-proof system coupled with ammonia decomposition according to claim 4, characterized in that: The gas channel is a hollow rectangular structure; the total volume of the solid part of the gas channel is greater than the total volume of the hollow part of the gas channel; the hollow part of the gas channel is filled with an ammonia decomposition catalyst; the ammonia decomposition catalyst is a ruthenium-based catalyst.

6. The positive pressure explosion-proof system coupled with ammonia decomposition according to claim 4, characterized in that: A control box is provided on the side of the housing; a temperature sensor and a pressure sensor are provided inside the housing; the control box is electrically connected to a first intake valve, a second intake valve, an exhaust valve, a heat dissipation exhaust valve, a temperature sensor, a pressure sensor, and multiple electric heating elements.

7. The positive pressure explosion-proof system coupled with ammonia decomposition according to claim 2, characterized in that: The positive pressure explosion-proof cabinet is connected to the heat exchanger; the heat exchanger is connected to the first purification module; the first purification module includes a water cooler, a TSA purification device, and a first buffer tank; the water cooler, the TSA purification device, and the first buffer tank are connected in series sequentially; the heat exchanger is connected to the water cooler; the second purification and drying module includes a hydrogen-nitrogen compressor, a second buffer tank, and a PSA purification device; the hydrogen-nitrogen compressor, the second buffer tank, and the PSA purification device are connected in series sequentially; the hydrogen-nitrogen compressor is also connected to the first buffer tank; the PSA purification device is connected to the booster compressor.

8. The positive pressure explosion-proof system coupled with ammonia decomposition according to claim 2, characterized in that: The purification and drying module includes a condenser, a dryer, and a water tank connected in sequence; the condenser is connected to the dryer; the dryer is connected to the nitrogen storage tank; the gas outlet of the palladium catalyst reactor is connected to the condenser; the nitrogen storage tank is then connected to the positive pressure explosion-proof cabinet, the dryer, and the TSA purification device. The condenser is circulatedly connected to the water tank; the cooling water in the water tank circulates between the water tank and the condenser; the water tank is also connected to the hydrogen-nitrogen compressor and the water cooler respectively; the water cooler is then connected to the liquid ammonia evaporator; the liquid water in the water tank can circulate between the water tank and the hydrogen-nitrogen compressor; the liquid water in the water tank can circulate between the water tank, the liquid ammonia evaporator, and the water cooler.

9. A control method for a positive pressure explosion-proof system coupled with ammonia decomposition as described in any one of claims 1 to 8; characterized in that: Includes the following steps: Step 1: Evaporate liquid ammonia into ammonia gas and introduce the evaporated ammonia gas into the reactor in the positive pressure explosion-proof cabinet; Step 2: Control the reactor to decompose ammonia into a hydrogen-nitrogen mixture; pass the hydrogen-nitrogen mixture sequentially through the first purification device and the second purification device; respectively complete the adsorption and removal of ammonia and the separation of hydrogen and nitrogen. Step 3: Adjust the internal pressure of the second purification unit and introduce the desorbed nitrogen and a small amount of hydrogen into the palladium catalyst reactor through a booster compressor; introduce air into the palladium catalyst reactor; control the palladium catalyst reactor to react hydrogen and oxygen to generate water vapor; Step 4: The nitrogen and water vapor in the palladium catalyst reactor are discharged and introduced into the purification and drying module for cooling and drying; nitrogen is obtained; the nitrogen is then introduced into a nitrogen storage tank for storage. Step 5: Introduce nitrogen from the nitrogen storage tank into the positive pressure explosion-proof cabinet; check the pressure inside the positive pressure explosion-proof cabinet; when the pressure is lower than the lower limit of the positive pressure explosion-proof cabinet; first increase the power of the booster or increase the gas flow rate into the palladium catalyst reactor, then increase the opening of the inlet valve and decrease the opening of the exhaust valve; when the pressure is higher than the upper limit of the positive pressure explosion-proof cabinet; first reduce the power of the booster or reduce the gas flow rate into the palladium catalyst reactor, then increase the opening of the exhaust valve and decrease the opening of the inlet valve; until the internal pressure of the positive pressure explosion-proof cabinet stabilizes within the preset pressure range.

10. A control method according to claim 9; characterized in that: In step five, first increase the power of the booster or increase the gas flow rate into the palladium catalyst reactor, and introduce nitrogen into the positive pressure explosion-proof cabinet by opening the inlet valve to continuously fill the positive pressure explosion-proof cabinet with nitrogen; detect the pressure in the positive pressure explosion-proof cabinet; and make the pressure in the positive pressure explosion-proof cabinet reach the upper limit. When the pressure of the positive pressure explosion-proof cabinet reaches the upper limit, first reduce the power of the booster or reduce the gas flow rate into the palladium catalyst reactor, then open the exhaust valve to depressurize the inside of the positive pressure explosion-proof cabinet and check the pressure in the positive pressure explosion-proof cabinet. When the pressure inside the positive pressure explosion-proof cabinet reaches the lower limit, increase the opening of the air inlet valve to introduce nitrogen into the positive pressure explosion-proof cabinet, and continue to monitor the pressure inside the positive pressure explosion-proof cabinet; If the pressure inside the positive pressure explosion-proof cabinet is detected to be greater than the upper limit for more than 30 seconds, or the pressure inside the positive pressure explosion-proof cabinet is detected to be less than the lower limit for more than 10 seconds, the heating of ammonia in the reactor should be stopped immediately.

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