Metal hydride reactor dehydrogenation helium extraction apparatus and method

Abstract

The present application relates to helium purification device and method, specifically relates to a kind of metal hydride reactor dehydrogenation helium extraction device and method, purpose is to solve the problems of insufficient pressure fluctuation suppression ability, energy utilization efficiency, energy consumption is higher or the problem of insufficient safety that helium purification technology exists.The present application device includes heat exchanger, first reactor and second reactor are filled with metal hydride and are in parallel, and hydrogen storage tank and related monitoring and control components;First reactor, second reactor and heat exchanger are connected with external public heat exchange equipment.The present application method includes alternately using first reactor, second reactor carries out adsorption and desorption work, and according to actual situation, hydrogen storage tank releases hydrogen, and the system is self-pressurized.The present application improves energy utilization efficiency, reduces the energy consumption of device overall, and the pressure fluctuation of entire system is stable.

Description

Technical Field

[0001] This invention relates to helium purification apparatus and methods, specifically to a dehydrogenation helium extraction apparatus and method based on a metal hydride reactor. Background Technology

[0002] Helium (He), as an important and scarce resource, has irreplaceable applications in semiconductor manufacturing, nuclear reactor cooling, optical fiber drawing, and low-temperature superconductivity. Efficiently purifying helium from industrial waste gas or natural gas containing hydrogen (H2) is a key technological path to address helium resource scarcity. Currently, helium purification technologies mainly include catalytic oxidation, low-temperature adsorption, and the emerging metal hydride separation method, but each technology has significant limitations.

[0003] Existing research indicates that the low thermal and mass transfer efficiency of metal hydrides in the clinical layer is a core bottleneck in hydrogen-helium separation applications. As described in the article "Metal hydride hydrogen compressors: A review" (see LOTOTSKYY MV, YARTYS VA, POLLET BG, et al. Metal hydride hydrogen compressors: Areview[J]. International Journal of Hydrogen Energy, 2014, 39(11): 5818-5851.), the effective thermal conductivity of metal hydride powder beds is extremely low (typically below 1 W / m·K), resulting in the inability to timely dissipate the adsorption heat generated during the hydrogen absorption / desorption reaction, leading to a severe lag in temperature response. This thermal lag effect directly causes drastic fluctuations in equilibrium hydrogen pressure, making it difficult to stably control the system pressure. Existing technologies typically rely solely on the pressure regulating valve at the inlet for passive adjustment, but the mechanical response speed of the valve is far from matching the transient pressure changes inside the bed, resulting in large fluctuations in product gas purity and even the risk of hydrogen permeation. The article clearly points out that relying solely on valve pressure regulation is insufficient to achieve stable matching of the pressure platform, and the system design must consider complex control strategies such as multi-stage compression and platform pressure synchronization.

[0004] In terms of energy utilization, existing technologies generally suffer from the energy waste problem of "heat-pressure decoupling". According to the summary of the article "Heat transfer techniques in metal hydride hydrogen storage: A review" (see AFZAL M, MANE R, SHARMA P. Heat transfer techniques in metal hydride hydrogenstorage: A review[J]. International Journal of Hydrogen Energy, 2017, 42(52):30661-30682.), the adsorption heat released during the adsorption process of metal hydrides is usually regarded as waste heat and needs to be discharged by external cooling systems (such as cooling towers or fans); while the desorption process requires external electric heating or steam heating to provide heat. This operation mode of simultaneously discharging heat and heating heat leads to high overall system energy consumption. More importantly, the pressure potential energy contained in the high-pressure hydrogen gas (pressure can reach 1~2 MPa) generated during the desorption process is often directly wasted, or output as a low-pressure product after depressurization, or directly discharged, failing to achieve the cascade utilization of energy. This thermodynamic decoupling design results in low energy efficiency for existing metal hydride systems.

[0005] Furthermore, traditional catalytic oxidation helium extraction processes are lengthy and pose safety hazards. For example, the process described in the article "The heliumpurification system of the HTR-10" (see YAO MS, WANG RP, LIU ZY, et al. Thehelium purification system of the HTR-10[J]. Nuclear Engineering and Design,2002, 218(1): 163-167.) includes multiple unit operations such as catalytic oxidation for hydrogen removal, molecular sieve adsorption for water removal, and low-temperature adsorption for nitrogen removal. This process requires continuous injection of oxygen into the bed to catalytically combust hydrogen to produce water, which is then removed. This not only results in large equipment investments and a long process chain, but the introduction of oxygen also poses a serious explosion hazard, placing stringent requirements on system sealing, oxygen content monitoring, and safety interlock control. For feed gas with fluctuating hydrogen content, catalytic oxidation is also prone to runaway temperatures or explosions due to uncontrolled hydrogen-oxygen ratios.

[0006] In addition, Chinese patent CN1066004A discloses a method for extracting helium from methanol tail gas and ammonia synthesis off-gas using a metal hydride method, while simultaneously obtaining high-purity hydrogen. This method employs a dual-tower process route combining a static hydrogen absorption separation process with a dynamic hydrogen absorption and helium release process. However, it also suffers from problems such as energy waste due to "thermal-pressure decoupling," reliance on external compressors, and insufficient pressure fluctuation suppression.

[0007] In summary, existing helium purification technologies suffer from three major drawbacks: first, insufficient pressure fluctuation suppression capabilities, with valve regulation alone insufficient to handle transient conditions; second, low energy utilization efficiency, as neither the heat of adsorption nor the pressure potential energy of desorbed hydrogen is effectively recovered, resulting in high energy consumption; and third, insufficient process safety, with the introduction of oxygen in traditional catalytic methods posing an explosion risk. Therefore, developing a highly efficient and safe helium extraction device capable of achieving thermo-pressure coupling and energy self-balancing has become a pressing technical challenge in this field. Summary of the Invention

[0008] The purpose of this invention is to solve the problems of insufficient pressure fluctuation suppression, low energy utilization efficiency, high energy consumption or insufficient safety in helium purification technology, and to provide a metal hydride reactor dehydrogenation helium extraction device and method.

[0009] To achieve the above objectives, the technical solution provided by this invention is as follows:

[0010] A metal hydride reactor for dehydrogenation and helium extraction is characterized by the following features:

[0011] It includes a heat exchanger, and a first reactor and a second reactor, both filled with metal hydrides; the first reactor, the second reactor, and the heat exchanger are all connected to an external common heat exchange device.

[0012] The first reactor and the second reactor are connected in parallel via pipelines. A first reactor inlet control valve is installed on the inlet pipeline of the first reactor, and a second reactor inlet control valve is installed on the inlet pipeline of the second reactor. The inlet pipelines of the first reactor and the second reactor are split at a branch point located upstream of the first and second reactor inlet control valves. A main inlet pipeline is installed upstream of the branch point, and a mixer and a hydrogen-helium mixture inlet control valve are sequentially installed on the main inlet pipeline from the farthest point to the nearest point. The first input end of the mixer is used to introduce the hydrogen-helium mixture.

[0013] The hydrogen output pipelines of the first reactor and the second reactor converge at a first junction point, and the helium output pipelines of the first reactor and the second reactor converge at a second junction point. A hydrogen circulation pipeline is located downstream of the first junction point, and its end is connected to the second input end of the mixer. A hydrogen recovery outlet control valve, a hydrogen storage tank, and a hydrogen storage tank pressure regulating valve are sequentially installed on the hydrogen circulation pipeline from near to far from the first junction point. A helium product output pipeline is located downstream of the second junction point, and a product gas outlet control valve is installed on the helium product output pipeline. The end of the helium product output pipeline is connected to an external helium collection device.

[0014] The heat exchanger is connected to the heat exchange pipelines of the first reactor and the second reactor respectively through heat circulation pipelines, and is used for heat transfer between the first reactor and the second reactor.

[0015] Furthermore, a hydrogen-helium mixture flow meter is installed between the hydrogen-helium mixture inlet control valve and the diversion point;

[0016] A product gas flow meter is also installed on the helium product output pipeline, and the product gas flow meter is located downstream of the product gas outlet control valve.

[0017] Furthermore, the metal hydride is a lanthanum-nickel based, titanium-iron based, or titanium-manganese based material.

[0018] Furthermore, a monitoring pipeline is installed at the second confluence point, and a product gas sampling control valve and a hydrogen concentration monitoring platform are sequentially installed on the monitoring pipeline from the nearest point to the farthest point from the second confluence point; a first temperature sensor for monitoring its internal temperature is installed on the first reactor, a second temperature sensor for monitoring its internal temperature is installed on the second reactor, and a hydrogen storage tank pressure sensor for monitoring its internal pressure is installed on the hydrogen storage tank; a total pipeline pressure sensor is installed on the pipeline between the mixer and the hydrogen-helium mixture inlet control valve.

[0019] Furthermore, the heat exchanger is a built-in finned tube heat exchanger; the heat transfer fluid in the heat exchanger is water or an aqueous solution of ethylene glycol.

[0020] Furthermore, a vacuum pump is installed on the pipeline between the first confluence point and the hydrogen recovery outlet control valve.

[0021] Furthermore, it also includes a control module;

[0022] The hydrogen-helium mixture inlet control valve, the first reactor inlet control valve, the second reactor inlet control valve, the product gas outlet control valve, the hydrogen recovery outlet control valve, the hydrogen storage tank pressure regulating valve, and the product gas sampling control valve are all solenoid valves.

[0023] The hydrogen-helium mixture inlet control valve, the first reactor inlet control valve, the second reactor inlet control valve, the product gas outlet control valve, the hydrogen recovery outlet control valve, the hydrogen storage tank pressure regulating valve, the product gas sampling control valve, the heat exchanger, the external common heat exchange equipment, the first temperature sensor, the second temperature sensor, the hydrogen storage tank pressure sensor, the hydrogen-helium mixture flow meter, the product gas flow meter, and the hydrogen concentration monitoring platform are all electrically connected to the control module.

[0024] The metal hydride is LaNi5.

[0025] Meanwhile, the present invention also provides a method for helium extraction via a metal hydride reactor, employing the aforementioned metal hydride reactor helium extraction apparatus, characterized by the inclusion of the following steps:

[0026] Step 1: Turn on the external common heat exchange equipment to preheat the first reactor until its internal temperature T1 reaches 20℃~30℃, and then turn off the external common heat exchange equipment.

[0027] Step 2: Introduce the hydrogen-helium mixture through the first input terminal of the mixer, and open the hydrogen-helium mixture inlet control valve and the first reactor inlet control valve to allow the hydrogen-helium mixture to reach the first reactor, where adsorption begins; monitor the hydrogen concentration at the second junction of the pipeline in real time. Real-time monitoring of the internal temperature T1 of the first reactor; real-time monitoring of the internal temperature T2 of the second reactor; real-time monitoring of the pressure inside the hydrogen storage tank. Open the product gas outlet control valve and collect helium products in real time through an external helium collection device;

[0028] Step 3: During the adsorption process in the first reactor, its internal temperature T1 begins to rise. When the hydrogen concentration at the second confluence point... When the hydrogen concentration is ≥0.8 ppm, or the internal temperature T1 of the first reactor is ≥35℃, open the pressure regulating valve of the hydrogen storage tank to allow hydrogen to flow out of the storage tank, mix with the hydrogen-helium mixture through the second input terminal of the mixer, and then enter the first reactor. Simultaneously monitor the total pressure in the pipeline. And the opening degree of the pressure regulating valve of the hydrogen storage tank is adjusted by feedback, so that... Maintain within the preset pressure range;

[0029] With the pressure regulating valve of the hydrogen storage tank open, the hydrogen concentration at the second junction point... When the concentration is ≥1.0 ppm, close the product gas outlet control valve;

[0030] When the hydrogen concentration at the second confluence point When the concentration is ≥1.5 ppm and the duration is greater than or equal to t (where t is the duration threshold in seconds), the inlet control valve of the first reactor and the pressure regulating valve of the hydrogen storage tank are closed. The inlet control valve of the second reactor, the hydrogen recovery outlet control valve, and the vacuum pump are opened, ensuring that all external common heat exchange equipment is shut off. The heat exchanger is then turned on, and heat exchange between the first and second reactors is carried out in real time through the heat transfer fluid. The internal temperature of the first reactor is maintained at 80 ℃~90 ℃, while the temperature of the second reactor is maintained at 20 ℃~30 ℃. This allows the first reactor to begin desorption, and the desorbed hydrogen is extracted by the vacuum pump and sent to the hydrogen storage tank. The second reactor then begins adsorption, and the product gas outlet control valve is opened. When the temperature difference between the first and second reactors is detected to be less than the preset temperature difference, the heat exchanger is turned off and the external common heat exchange equipment is turned on.

[0031] Step 4: During the adsorption process in the second reactor, its internal temperature T2 begins to rise. When the hydrogen concentration at the second confluence point... When the hydrogen concentration is ≥0.8 ppm, or the internal temperature T2 of the second reactor is ≥35℃, open the pressure regulating valve of the hydrogen storage tank to allow hydrogen to flow out of the storage tank, mix with the hydrogen-helium mixture through the second input terminal of the mixer, and then enter the second reactor. Simultaneously monitor the total pressure in the pipeline. And the opening degree of the pressure regulating valve of the hydrogen storage tank is adjusted by feedback, so that... Maintain within the preset pressure range;

[0032] With the pressure regulating valve of the hydrogen storage tank open, the hydrogen concentration at the second junction point... When the concentration is ≥1.0 ppm, close the product gas outlet control valve;

[0033] When the hydrogen concentration at the second confluence point When the concentration is ≥1.5 ppm and the duration is greater than or equal to t, close the inlet control valve of the second reactor and the pressure regulating valve of the hydrogen storage tank, open the inlet control valve of the first reactor and the hydrogen recovery outlet control valve, so that all external common heat exchange equipment is in the off state, turn on the heat exchanger, and conduct heat exchange between the first reactor and the second reactor in real time through the heat transfer fluid, so that the internal temperature of the second reactor is maintained at 80 ℃~90 ℃, while the temperature of the first reactor is maintained at 20 ℃~30 ℃, so that the second reactor begins desorption, the desorbed hydrogen is extracted by the vacuum pump and sent to the hydrogen storage tank, and the first reactor begins adsorption, then open the product gas outlet control valve, and when the temperature difference between the first reactor and the second reactor is detected to be less than the preset temperature difference, turn off the heat exchanger and turn on the external common heat exchange equipment;

[0034] Step 5: Repeat steps 3 and 4 sequentially until the pressure inside the hydrogen storage tank reaches a certain level. When the critical warning value is reached, or when the volume of helium product collected by the external helium collection device reaches the actual required volume, the cycle ends and the metal hydride reactor dehydrogenation and helium extraction unit is shut down.

[0035] Furthermore, step 2 also includes: monitoring the flow rate of helium products in real time using a product gas flow meter; simultaneously, monitoring the flow rate of the hydrogen-helium mixture in real time using a hydrogen-helium mixture flow meter, and adjusting the hydrogen-helium mixture inlet control valve in real time based on the monitored flow rate value of the hydrogen-helium mixture to stabilize the flow rate of the hydrogen-helium mixture within the preset flow range.

[0036] In step 2, the hydrogen concentration at the second junction of the pipeline is monitored in real time using the opened product gas sampling control valve and the hydrogen concentration monitoring platform. The internal temperature T1 of the first reactor is monitored in real time using a first temperature sensor; the internal temperature T2 of the second reactor is monitored in real time using a second temperature sensor; and the pressure inside the hydrogen storage tank is monitored in real time using a hydrogen storage tank pressure sensor. ;

[0037] In step 3, the total pipeline pressure is monitored using a pipeline total pressure sensor. .

[0038] Further, in step 3, the preset pressure range is 119.5 kPa to 120.5 kPa; t The value range is 30 s to 60 s.

[0039] Compared with the prior art, the present invention has the following beneficial technical effects:

[0040] 1. The metal hydride reactor dehydrogenation and helium extraction device provided by this invention, wherein the first reactor and the second reactor alternately perform absorption and desorption operations, with at most one reactor performing absorption and at most one reactor performing desorption operations at the same time. The "heat of adsorption" is used to generate "high pressure for desorption", and the "high pressure for desorption" is then used to stabilize the "adsorption process", forming a dual cycle of heat and matter. That is, the heat generated by the adsorption of one reactor is effectively used to heat the other reactor, making the adsorption operation of one reactor more sustained, and the other reactor can also fully desorb hydrogen, thereby improving energy utilization efficiency. With this setup, the required external additional heat or cold is also less, reducing the overall energy consumption of the device and improving economic efficiency.

[0041] 2. The metal hydride reactor dehydrogenation and helium extraction device provided by this invention collects the desorbed hydrogen gas through a hydrogen storage tank. By adjusting the opening of the pressure regulating valve of the hydrogen storage tank, the high-pressure potential energy of the desorbed hydrogen gas is used as the pressurization power for the hydrogen-helium mixture. The raw material gas pressure sensor monitors the pressure in real time, realizing the overall device's precise self-pressurization on demand. It can compensate for adsorption capacity loss without the intervention of external compressors or other pressurization devices, solving the problem of insufficient pressure fluctuation suppression capability in the prior art, and also improving safety.

[0042] 3. The metal hydride reactor helium extraction device provided by this invention requires only two reactors, making the process simple. Both the first and second reactors are metal hydride reactors, filled with lanthanum-nickel (such as LaNi5), titanium-iron, or titanium-manganese materials. Metal hydrides have a specific chemical adsorption capacity for hydrogen, and when heated to a certain temperature, they can release high-pressure hydrogen. The hydrogen adsorption and desorption reactions are completely reversible, reusable, and the energy can be utilized in stages. No dangerous gases such as oxygen are required, thus improving safety.

[0043] 4. The metal hydride reactor dehydrogenation and helium extraction device provided by the present invention uses water or ethylene glycol aqueous solution as the heat exchange fluid in its heat exchanger. Water has extremely high specific heat capacity and excellent convective heat transfer coefficient, and has no phase change (i.e., it does not boil or vaporize) and low viscosity, enabling efficient heat exchange with extremely low pumping power consumption. If the heat exchanger is deployed in an environment with a risk of freezing, ethylene glycol aqueous solution can be selected as the heat exchange fluid with antifreeze function. The heat exchanger is preferably a built-in finned tube heat exchanger with high heat transfer efficiency.

[0044] 5. The metal hydride reactor dehydrogenation and helium extraction method provided by this invention does not require the intervention of an external compressor, saving overall energy consumption. Furthermore, by coordinating the first reactor, the second reactor, and the heat exchanger that alternately perform adsorption and desorption operations, heat recycling is achieved, and the final helium product has high purity with a hydrogen impurity concentration of less than 1 ppm. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of an embodiment of the metal hydride reactor helium extraction device of the present invention.

[0046] The annotations in the attached figures are explained as follows:

[0047] 1-First reactor, 2-Second reactor, 3-Hydrogen storage tank, 4-Heat exchanger, 5-Hydrogen concentration monitoring platform, 6-Vacuum pump, 7-Hydrogen-helium mixed gas flow meter, 8-Product gas flow meter, 9-Mixer, 10-Hydrogen-helium mixed gas inlet control valve, 11-First reactor inlet control valve, 12-Second reactor inlet control valve, 13-Product gas outlet control valve, 14-Hydrogen recovery outlet control valve, 15-Hydrogen storage tank pressure regulating valve, 16-Product gas sampling control valve, 17-First temperature sensor, 18-Second temperature sensor, 19-Hydrogen storage tank pressure sensor, 20-Pipeline total pressure sensor, 21-Branch point, 22-First junction point, 23-Second junction point. Detailed Implementation

[0048] To make the objectives, advantages, and features of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0049] like Figure 1 As shown, this embodiment provides a metal hydride reactor dehydrogenation and helium extraction device, which is a set of dehydrogenation and helium extraction devices composed of two metal hydride reactors; it includes a heat exchanger 4, and a first reactor 1 and a second reactor 2, both filled with metal hydride; the first reactor 1, the second reactor 2 and the heat exchanger 4 are all connected to an external common heat exchange equipment.

[0050] The first reactor 1 and the second reactor 2 are connected in parallel via pipelines, each with an input end, a hydrogen output end, and a helium output end. The input end pipeline of the first reactor 1 is equipped with a first reactor inlet control valve 11, and the input end pipeline of the second reactor 2 is equipped with a second reactor inlet control valve 12. The input end pipelines of the first reactor 1 and the second reactor 2 are split at a split point 21 located upstream of the first reactor inlet control valve 11 and the second reactor inlet control valve 12. A main input pipeline is located upstream of the split point 21, and a mixer 9, a pipeline total pressure sensor 20, a hydrogen-helium mixture inlet control valve 10, and a hydrogen-helium mixture flow meter 7 are arranged sequentially from the distance from the split point 21 to the distance from the main input pipeline. The mixer 9 has two input ends and one output end, and the first input end of the mixer 9 is used to introduce hydrogen-helium mixture.

[0051] The hydrogen output pipeline of the first reactor 1 and the hydrogen output pipeline of the second reactor 2 converge at the first junction point 22, and the helium output pipeline of the first reactor 1 and the helium output pipeline of the second reactor 2 converge at the second junction point 23.

[0052] A hydrogen circulation pipeline is provided downstream of the first confluence point 22, and the end of the hydrogen circulation pipeline is connected to the second input end of the mixer 9; a hydrogen recovery outlet control valve 14, a hydrogen storage tank 3 and a hydrogen storage tank pressure regulating valve 15 are provided on the hydrogen circulation pipeline from the first confluence point 22 in order from the nearest to the farthest point.

[0053] Downstream of the second confluence point 23, there is a helium product output pipeline, and the helium product output pipeline is equipped with a product gas outlet control valve 13 and a product gas flow meter 8; the end of the helium product output pipeline is connected to an external helium collection device.

[0054] A monitoring pipeline is installed at the second confluence point 23, and a product gas sampling control valve 16 and a hydrogen concentration monitoring platform 5 are installed sequentially from the second confluence point 23 to the farthest point (when the adsorption is close to saturation, the hydrogen concentration will gradually increase, so a hydrogen concentration monitoring platform 5 is required for real-time monitoring); a first temperature sensor 17 for monitoring its internal temperature is installed on the first reactor 1, a second temperature sensor 18 for monitoring its internal temperature is installed on the second reactor 2, and a hydrogen storage tank pressure sensor 19 for monitoring its internal pressure is installed on the hydrogen storage tank 3.

[0055] Heat exchanger 4 is connected to the heat exchange pipelines of the first reactor 1 and the second reactor 2 via heat circulation pipelines, and is used for heat transfer between the first reactor 1 and the second reactor 2. Heat exchanger 4 is a built-in finned tube heat exchanger; the heat transfer fluid in heat exchanger 4 can be water or an aqueous ethylene glycol solution. In this embodiment, water is chosen because it has extremely high specific heat capacity and excellent convective heat transfer coefficient, and it has no phase change (i.e., does not boil or vaporize), low viscosity, and can achieve efficient heat exchange with extremely low pumping power consumption. If heat exchanger 4 is deployed in an environment with a risk of freezing, an aqueous ethylene glycol solution can be used as a heat exchange fluid with antifreeze function. Heat exchanger 4 is preferably a built-in finned tube heat exchanger, which has high heat transfer efficiency.

[0056] In practical applications, metal hydrides can be selected from lanthanum-nickel, titanium-iron, or titanium-manganese materials. In this embodiment, LaNi5 is selected because it has a specific and highly selective chemical adsorption capacity for hydrogen, and its energy can be utilized in a cascade manner without the need for the introduction of dangerous gases such as oxygen, thus improving safety.

[0057] A vacuum pump 6 is installed on the pipeline between the first junction point 22 and the hydrogen recovery outlet control valve 14 for transporting hydrogen.

[0058] The hydrogen-helium mixture inlet control valve 10, the first reactor inlet control valve 11, the second reactor inlet control valve 12, the product gas outlet control valve 13, the hydrogen recovery outlet control valve 14, the hydrogen storage tank pressure regulating valve 15, and the product gas sampling control valve 16 are all solenoid valves. The hydrogen-helium mixture inlet control valve 10, the first reactor inlet control valve 11, the second reactor inlet control valve 12, the product gas outlet control valve 13, the hydrogen recovery outlet control valve 14, the hydrogen storage tank pressure regulating valve 15, the product gas sampling control valve 16, the heat exchanger 4, the vacuum pump 6, the external common heat exchange equipment, the first temperature sensor 17, the second temperature sensor 18, the hydrogen storage tank pressure sensor 19, the hydrogen-helium mixture flow meter 7, the product gas flow meter 8, and the hydrogen concentration monitoring platform 5 are all electrically connected to the control module.

[0059] This embodiment also provides a method for helium extraction via a metal hydride reactor, employing the aforementioned metal hydride reactor helium extraction apparatus, and includes the following steps:

[0060] Step 1: Turn on the external common heat exchange equipment to preheat the first reactor 1, so that its internal temperature T1 reaches 20 ℃~30 ℃, and then turn off the external common heat exchange equipment; the external common heat exchange equipment can intelligently deliver cold or heat to the first reactor 1, the second reactor 2 and the heat exchanger 4, and realize a certain degree of intelligent temperature regulation so that the first reactor 1 and the second reactor 2 meet the working temperature requirements.

[0061] Step 2: Introduce the hydrogen-helium mixture through the first input terminal of mixer 9, and open the hydrogen-helium mixture inlet control valve 10 and the first reactor inlet control valve 11 to allow the hydrogen-helium mixture to reach the first reactor 1, where adsorption begins. The product gas sampling control valve 16, after being opened, monitors the hydrogen concentration at the second confluence point 23 of the pipeline in real time via the hydrogen concentration monitoring platform 5. The internal temperature T1 of the first reactor 1 is monitored in real time by the first temperature sensor 17; the internal temperature T2 of the second reactor 2 is monitored in real time by the second temperature sensor 18; and the pressure inside the hydrogen storage tank 3 is monitored in real time by the hydrogen storage tank pressure sensor 19. Open the product gas outlet control valve 13, and the external helium collection device collects helium products in real time; monitor the flow rate of helium products in real time through the product gas flow meter 8; at the same time, monitor the flow rate of hydrogen-helium mixture in real time through the hydrogen-helium mixture flow meter 7, and adjust the hydrogen-helium mixture inlet control valve 10 in real time according to the monitored flow rate value of hydrogen-helium mixture, so that the flow rate of hydrogen-helium mixture from the outside is stabilized within the preset flow range.

[0062] Step 3: During the adsorption process in the first reactor 1, its internal temperature T1 begins to rise. When the concentration is ≥0.8 ppm or T1 ≥35 ℃ (indicating localized adsorption heat accumulation and adsorption kinetic decay in the first reactor 1), the pressure regulating valve 15 of the hydrogen storage tank is opened, allowing hydrogen to flow out of the hydrogen storage tank 3. This hydrogen then mixes with the hydrogen-helium mixture through the second input terminal of the mixer 9 before entering the first reactor 1. Simultaneously, the total pipeline pressure is monitored by the pipeline total pressure sensor 20. And the opening degree of the hydrogen storage tank pressure regulating valve 15 is adjusted by feedback, so that... Maintain within the preset pressure range; with the hydrogen storage tank pressure regulating valve 15 open, when Immediately close the product gas outlet control valve 13 when the concentration is ≥1.0 ppm to ensure the purity of the helium product; when When the continuous maintenance time of ≥1.5 ppm is greater than or equal to t=60 s (indicating that the LaNi5 bed has completely reached its thermodynamic saturation capacity and the reactor must be switched immediately; in actual practice, the maintenance time threshold t can be adjusted, and if the purity requirement of the helium product is higher, it can also be adjusted to 30 s), close the first reactor inlet control valve 11 and the hydrogen storage tank pressure regulating valve 15, and open the second reactor inlet control valve 12, the hydrogen recovery outlet control valve 14, and the vacuum pump 6, so that all external common heat exchange equipment is in a cut-off state. Turn on the heat exchanger 4, and conduct heat exchange between the first reactor 1 and the second reactor 2 in real time through the heat transfer fluid, so that the internal temperature T1 of the first reactor 1 is maintained at 80 ℃~90 ℃ (preferably 85 ℃), while the temperature of the second reactor 2 is maintained at 20 ℃~30 ℃. The temperature is set to ℃, causing the first reactor 1 to begin desorption. The desorbed hydrogen is extracted by the vacuum pump 6 and sent to the hydrogen storage tank 3, and the second reactor 2 begins adsorption. Then the product gas outlet control valve 13 is opened. When the temperature difference between the first reactor 1 and the second reactor 2 is detected to be less than the preset temperature difference, the heat exchanger 4 is shut down and the external common heat exchange equipment is turned on.

[0063] Step 4: During the adsorption process in the second reactor 2, its internal temperature T2 begins to rise. When the concentration of hydrogen gas is ≥0.8 ppm or T2 is ≥35 °C (indicating localized heat accumulation and adsorption kinetic decay in the second reactor 2), the pressure regulating valve 15 of the hydrogen storage tank is opened, allowing hydrogen gas to flow out of the hydrogen storage tank 3, mix with the hydrogen-helium mixture through the second input terminal of the mixer 9, and then enter the second reactor 2. Simultaneously, the total pressure in the pipeline is monitored. And the opening degree of the hydrogen storage tank pressure regulating valve 15 is adjusted by feedback, so that... Maintaining the pressure at 119.5 kPa to 120.5 kPa is to compensate for the decrease in adsorption capacity caused by temperature fluctuations, forcing the metal hydride to maintain adsorption activity at a higher partial pressure, thus locking in the purity of the product helium; with the pressure regulating valve 15 of the hydrogen storage tank open, when Immediately close the product gas outlet control valve 13 when the concentration is ≥1.0 ppm to ensure the purity of the helium product; when When the continuous maintenance time of ≥1.5 ppm is greater than or equal to 60 s, close the second reactor inlet control valve 12 and the hydrogen storage tank pressure regulating valve 15, and open the first reactor inlet control valve 11, the hydrogen recovery outlet control valve 14 and the vacuum pump 6 to ensure that all external common heat exchange equipment is in the off state. Turn on the heat exchanger 4 and conduct heat exchange between the first reactor 1 and the second reactor 2 in real time through the heat transfer fluid to maintain the internal temperature of the second reactor 2 at 80 ℃~90 ℃ (preferably 85 ℃), while maintaining the temperature of the first reactor 1 at 20 ℃~30 ℃, so that the second reactor 2 begins desorption. The desorbed hydrogen is extracted by the vacuum pump 6 and sent to the hydrogen storage tank 3, and the first reactor 1 begins adsorption. Then, open the product gas outlet control valve 13. When the temperature difference between the first reactor 1 and the second reactor 2 is less than the preset temperature difference, turn off the heat exchanger 4 and turn on the external common heat exchange equipment.

[0064] Step 5: Repeat steps 3 and 4 in sequence until... When the critical warning value is reached, or when the volume of helium product collected by the external helium collection device reaches the actual required volume, the cycle ends, the metal hydride reactor dehydrogenation and helium extraction unit is shut down, and the entire dehydrogenation and helium extraction process ends.

[0065] Note: The heat transfer fluid forms a closed-loop circulation only between the internal heat exchangers of the first reactor 1 and the second reactor 2. High-grade waste heat (80℃~90℃) from the bed of the second reactor 2 is used to directly heat the first reactor 1, which is at 20℃~30℃. During this process, the second reactor 2 is physically cooled, while the first reactor 1 is physically heated. The closed-loop heat recovery stage ends when the temperature difference monitored by the first temperature sensor 17 and the second temperature sensor 18 is less than a preset temperature difference.

[0066] In this embodiment, the working principle of the adsorption and desorption processes of the first reactor 1 and the second reactor 2 is based on a variation of the van Horowough equation, as shown in the following formula:

[0067]

[0068] Where ln is the natural logarithm function, P eq P is the equilibrium pressure for the hydrogen absorption or desorption reaction of the metal hydride, ΔH is the enthalpy change for the hydrogen absorption or desorption reaction of the metal hydride, R is the ideal gas constant, taken as 8.314 J / (mol·K), T is the reaction temperature in K, and ΔS is the entropy change for the hydrogen absorption or desorption reaction of the metal hydride. From the above formulas, it can be seen that P... eqThe growth rate increases exponentially with increasing temperature (T), meaning that during desorption, either reactor 1 or reactor 2 can directly "press out" high-pressure hydrogen using heat without the need for an external compressor.

[0069] Table 1 is a comparison table of the effects of this embodiment and the prior art.

[0070] Table 1. Comparison of the effects of this embodiment with existing technologies.

[0071]

[0072] As can be seen from Table 1, the helium product prepared in this embodiment has extremely high purity and stability with no risk of penetration; at the same time, the pressure curve in the entire device is flat, maximizing the utilization rate of adsorption capacity; this embodiment utilizes physical pressure increase by temperature difference, eliminating the need for mechanical compression equipment; compared with the prior art, it can save approximately 55% of energy.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present invention.

Claims

1. A metal hydride reactor for dehydrogenation and helium extraction, characterized in that: It includes a heat exchanger (4), and a first reactor (1) and a second reactor (2) both filled with metal hydrides; the first reactor (1), the second reactor (2) and the heat exchanger (4) are all connected to an external common heat exchange device; The first reactor (1) and the second reactor (2) are connected in parallel via pipelines. The first reactor (1) is provided with a first reactor inlet control valve (11) on the input pipeline and the second reactor (2) is provided with a second reactor inlet control valve (12) on the input pipeline. The input pipelines of the first reactor (1) and the second reactor (2) are connected by a split point (21) located upstream of the first reactor inlet control valve (11) and the second reactor inlet control valve (12). A main input pipeline is provided upstream of the split point (21), and a mixer (9) and a hydrogen-helium mixture inlet control valve (10) are provided on the main input pipeline from far to near the split point (21). The first input end of the mixer (9) is used to introduce hydrogen-helium mixture. The hydrogen output pipeline of the first reactor (1) and the hydrogen output pipeline of the second reactor (2) converge at the first junction (22), and the helium output pipeline of the first reactor (1) and the helium output pipeline of the second reactor (2) converge at the second junction (23). A hydrogen circulation pipeline is provided downstream of the first junction (22), and the end of the hydrogen circulation pipeline is connected to the second input end of the mixer (9). A hydrogen recovery outlet control valve (14), a hydrogen storage tank (3) and a hydrogen storage tank pressure regulating valve (15) are provided in sequence from near to far from the first junction (22) on the hydrogen circulation pipeline. A helium product output pipeline is provided downstream of the second junction (23), and a product gas outlet control valve (13) is provided on the helium product output pipeline. The end of the helium product output pipeline is connected to an external helium collection device. The heat exchanger (4) is connected to the heat exchange pipelines of the first reactor (1) and the second reactor (2) respectively through the heat circulation pipeline, and is used for heat transfer between the first reactor (1) and the second reactor (2).

2. The metal hydride reactor dehydrogenation and helium extraction apparatus according to claim 1, characterized in that: A hydrogen-helium mixture flow meter (7) is installed between the hydrogen-helium mixture inlet control valve (10) and the diversion point (21). A product gas flow meter (8) is also installed on the helium product output pipeline, and the product gas flow meter (8) is located downstream of the product gas outlet control valve (13).

3. The metal hydride reactor dehydrogenation and helium extraction apparatus according to claim 1, characterized in that: The metal hydride is a lanthanum-nickel based, titanium-iron based, or titanium-manganese based material.

4. The metal hydride reactor dehydrogenation and helium extraction apparatus according to claim 1, characterized in that: A monitoring pipeline is provided at the second junction point (23), and a product gas sampling control valve (16) and a hydrogen concentration monitoring platform (5) are provided on the monitoring pipeline from the second junction point (23) in order from the nearest to the farthest point. A first temperature sensor (17) for monitoring its internal temperature is provided on the first reactor (1), a second temperature sensor (18) for monitoring its internal temperature is provided on the second reactor (2), and a hydrogen storage tank pressure sensor (19) for monitoring its internal pressure is provided on the hydrogen storage tank (3). A total pipeline pressure sensor (20) is provided on the pipeline between the mixer (9) and the hydrogen-helium mixture inlet control valve (10).

5. The metal hydride reactor dehydrogenation and helium extraction apparatus according to any one of claims 1 to 4, characterized in that: The heat exchanger (4) is a built-in finned tube heat exchanger; the heat transfer fluid in the heat exchanger (4) is water or an aqueous solution of ethylene glycol.

6. The metal hydride reactor dehydrogenation and helium extraction apparatus according to claim 5, characterized in that: A vacuum pump (6) is installed on the pipeline between the first junction (22) and the hydrogen recovery outlet control valve (14).

7. The metal hydride reactor dehydrogenation and helium extraction apparatus according to claim 6, characterized in that: It also includes a control module; The hydrogen-helium mixture inlet control valve (10), the first reactor inlet control valve (11), the second reactor inlet control valve (12), the product gas outlet control valve (13), the hydrogen recovery outlet control valve (14), the hydrogen storage tank pressure regulating valve (15), and the product gas sampling control valve (16) are all solenoid valves. The hydrogen-helium mixed gas inlet control valve (10), the first reactor inlet control valve (11), the second reactor inlet control valve (12), the product gas outlet control valve (13), the hydrogen recovery outlet control valve (14), the hydrogen storage tank pressure regulating valve (15), the product gas sampling control valve (16), the heat exchanger (4), the external common heat exchange equipment, the first temperature sensor (17), the second temperature sensor (18), the hydrogen storage tank pressure sensor (19), the hydrogen-helium mixed gas flow meter (7), the product gas flow meter (8), and the hydrogen concentration monitoring platform (5) are all electrically connected to the control module; The metal hydride is LaNi5.

8. A method for dehydrogenation and helium extraction using a metal hydride reactor, employing the metal hydride reactor dehydrogenation and helium extraction apparatus according to any one of claims 1 to 7, characterized in that, Includes the following steps: Step 1: Turn on the external common heat exchange equipment to preheat the first reactor (1) until its internal temperature T1 reaches 20℃~30℃, and then turn off the external common heat exchange equipment. Step 2: Introduce the hydrogen-helium mixture through the first input end of the mixer (9), open the hydrogen-helium mixture inlet control valve (10) and the first reactor inlet control valve (11) to allow the hydrogen-helium mixture to reach the first reactor (1), and the first reactor (1) begins adsorption; monitor the hydrogen concentration at the second junction (23) of the pipeline in real time. Real-time monitoring of the internal temperature T1 of the first reactor (1); real-time monitoring of the internal temperature T2 of the second reactor (2); real-time monitoring of the pressure inside the hydrogen storage tank (3). ; Open the product gas outlet control valve (13) and collect helium products in real time through an external helium collection device; Step 3: During the adsorption process in the first reactor (1), its internal temperature T1 begins to rise. When the hydrogen concentration at the second confluence point (23) increases... When the hydrogen concentration is ≥0.8 ppm, or the internal temperature T1 of the first reactor (1) is ≥35℃, the pressure regulating valve (15) of the hydrogen storage tank is opened, allowing hydrogen to flow out from the hydrogen storage tank (3), pass through the second input end of the mixer (9), mix with the hydrogen-helium mixture, and then enter the first reactor (1). At the same time, the total pressure of the pipeline is monitored. And the opening degree of the hydrogen storage tank pressure regulating valve (15) is adjusted by feedback, so that Maintain within the preset pressure range; With the hydrogen storage tank pressure regulating valve (15) open, the hydrogen concentration at the second junction point (23) is... When the concentration is ≥1.0 ppm, close the product gas outlet control valve (13). When the hydrogen concentration at the second confluence point (23) When the concentration is ≥1.5 ppm and the duration is greater than or equal to t, where t is the duration threshold in seconds, the first reactor inlet control valve (11) and the hydrogen storage tank pressure regulating valve (15) are closed, and the second reactor inlet control valve (12), the hydrogen recovery outlet control valve (14), and the vacuum pump (6) are opened, so that all external common heat exchange equipment is cut off. The heat exchanger (4) is turned on, and heat exchange between the first reactor (1) and the second reactor (2) is carried out in real time through the heat transfer fluid, so that the internal temperature of the first reactor (1) is maintained at 80 ℃~90 ℃, and the temperature of the second reactor (2) is maintained at 20 ℃~30 ℃, so that the first reactor (1) begins to desorb, and the desorbed hydrogen is extracted by the vacuum pump (6) and sent into the hydrogen storage tank (3), and the second reactor (2) begins to adsorb. Then the product gas outlet control valve (13) is turned on. When the temperature difference between the first reactor (1) and the second reactor (2) is less than the preset temperature difference, the heat exchanger (4) is turned off and the external common heat exchange equipment is turned on. Step 4: During the adsorption process in the second reactor (2), its internal temperature T2 begins to rise. When the hydrogen concentration at the second confluence point (23) increases... When the hydrogen concentration is ≥0.8 ppm, or the internal temperature T2 of the second reactor (2) is ≥35℃, the pressure regulating valve (15) of the hydrogen storage tank is opened, allowing hydrogen to flow out from the hydrogen storage tank (3), pass through the second input end of the mixer (9), mix with the hydrogen-helium mixture, and then enter the second reactor (2). At the same time, the total pressure of the pipeline is monitored. And the opening degree of the hydrogen storage tank pressure regulating valve (15) is adjusted by feedback, so that Maintain within the preset pressure range; With the hydrogen storage tank pressure regulating valve (15) open, the hydrogen concentration at the second junction point (23) is... When the concentration is ≥1.0 ppm, close the product gas outlet control valve (13). When the hydrogen concentration at the second confluence point (23) When the concentration is ≥1.5 ppm and the duration is greater than or equal to t, the second reactor inlet control valve (12) and the hydrogen storage tank pressure regulating valve (15) are closed, the first reactor inlet control valve (11) and the hydrogen recovery outlet control valve (14) are opened, so that all external common heat exchange equipment is cut off, the heat exchanger (4) is turned on, and the heat exchange between the first reactor (1) and the second reactor (2) is carried out in real time through the heat transfer fluid, so that the internal temperature of the second reactor (2) is maintained at 80 ℃~90 ℃, and the temperature of the first reactor (1) is maintained at 20 ℃~30 ℃, so that the second reactor (2) begins to desorb, and the desorbed hydrogen is extracted by the vacuum pump (6) and sent into the hydrogen storage tank (3), and the first reactor (1) begins to adsorb. Then the product gas outlet control valve (13) is turned on. When the temperature difference between the first reactor (1) and the second reactor (2) is less than the preset temperature difference, the heat exchanger (4) is turned off and the external common heat exchange equipment is turned on. Step 5: Repeat steps 3 and 4 in sequence until the pressure inside the hydrogen storage tank (3) reaches a certain level. When the critical warning value is reached, or when the volume of helium product collected by the external helium collection device reaches the actual required volume, the cycle ends and the metal hydride reactor dehydrogenation and helium extraction unit is shut down.

9. The method for dehydrogenation and helium extraction from a metal hydride reactor according to claim 8, characterized in that: Step 2 also includes: monitoring the flow rate of helium products in real time through the product gas flow meter (8); at the same time, monitoring the flow rate of hydrogen-helium mixture in real time through the hydrogen-helium mixture flow meter (7), and adjusting the hydrogen-helium mixture inlet control valve (10) in real time according to the monitored flow rate value of hydrogen-helium mixture, so that the flow rate of hydrogen-helium mixture is stable within the preset flow range. In step 2, the hydrogen concentration at the second junction (23) of the pipeline is monitored in real time by the opened product gas sampling control valve (16) and the hydrogen concentration monitoring platform (5). The internal temperature T1 of the first reactor (1) is monitored in real time by the first temperature sensor (17); the internal temperature T2 of the second reactor (2) is monitored in real time by the second temperature sensor (18); and the pressure inside the hydrogen storage tank (3) is monitored in real time by the hydrogen storage tank pressure sensor (19). ; In step 3, the total pipeline pressure is monitored by the total pipeline pressure sensor (20). .

10. The method for dehydrogenation and helium extraction using a metal hydride reactor according to claim 9, characterized in that: In step 3, the preset pressure range is 119.5 kPa to 120.5 kPa; t The value range is 30 s to 60 s.

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