Rapid hydrogen filling system, inerting system and control method thereof

Abstract

The invention provides a rapid hydrogen filling system which comprises a plurality of high-pressure hydrogen cylinders connected in parallel and is characterized in that one ends of the high-pressure hydrogen cylinders connected in parallel are provided with conveying pipelines connected with a gas receiving cylinder, and the other ends of the high-pressure hydrogen cylinders connected in parallel are provided with input pipelines connected with one end of a compressor; the other end of the compressor is connected with the gas collecting bottle through a third pipeline, and a fourth pipeline is connected between the gas collecting bottle and the gas receiving bottle. A delayed filling strategy is designed by applying a temperature rise steep drop mechanism, the temperature rise of the first scheme and the temperature rise of the second scheme are 54.8 DEG C and 61.2 DEG C respectively after filling is completed, and the temperature rise of the first scheme and the temperature rise of the second scheme are reduced by 15.7% and 5.8% respectively compared with an original scheme; the rising rate of the average pressure of the scheme 1 and the scheme 2 is obviously reduced compared with that of the original scheme; the filling rate (SOC) of the first scheme and the filling rate (SOC) of the second scheme reach 87.33% and 87.36% respectively, and the filling rate of the first scheme and the filling rate of the second scheme are improved by 21.83% and 21.84% respectively compared with an original scheme.

Description

Technical Field

[0001] The present invention belongs to the technical field of pressure vessels, and in particular relates to a hydrogen rapid filling system, an inerting system and a control method thereof. Background Art

[0002] Safe, economical and efficient hydrogen storage technology is an important guarantee for the application and industrialization of hydrogen energy. At present, compressed hydrogen is stored in gas cylinders, which can obtain the advantages of high-density storage, low weight and low cost. However, the rapid filling process of high-pressure hydrogen storage cylinders is accompanied by a temperature rise effect. The drastic pressure and temperature changes will affect the mechanical properties of epoxy resin, threaten the fatigue life of high-pressure hydrogen storage cylinders, and also affect their filling rate (State of Charge, SOC). Therefore, in order to prevent the maximum temperature of hydrogen from exceeding the temperature threshold, it is very important to study the temperature rise characteristics of the gas and the hydrogenation strategy.

[0003] Many scholars have paid attention to the temperature rise and pressure during the hydrogen filling process of high-pressure hydrogen storage cylinders from multiple angles, and have obtained some meaningful conclusions. For example, Sung Chan Kim et al. studied the influence of different initial pressures in the bottle on the temperature rise change during the hydrogen filling process of high-pressure hydrogen storage cylinders. The results showed that the maximum temperature rise in the bottle during the filling process decreased with the increase of initial pressure. M. Heitsch, M. Cristina Galassi et al. further studied the influence of adiabatic filling, pressure rise rate and precooling during the filling of hydrogen storage cylinders on the basis of studying the initial pressure. Zheng et al. studied the influence of ambient temperature conditions on the final temperature rise of the gas. The results showed that with the increase of ambient temperature, the final gas temperature increased linearly. Ramasamy et al. studied the configuration of the inlet of the gas cylinder. The results showed that by distributing the hydrogen injection between different nozzles, the heat transfer between the hydrogen and the inner wall of the gas cylinder can be enhanced and the peak gas temperature can be reduced.

[0004] He Guangli, R. Ortiz Cebolla, N. de Miguel and others studied the effects of the initial temperature and mass flow rate of type III and type IV hydrogen storage cylinders on the cylinder filling rate (SOC). The results showed that the effects of mass flow rate and initial temperature on SOC in type IV cylinders were greater than those in type III cylinders. Kim et al. studied the relationship between the maximum temperature rise inside the cylinder and SOC. Seung et al. studied the Reynolds number and Nusselt number during the filling process, and systematically analyzed the relationship between these data and SOC. The results showed that the temperature rise of the hydrogen storage device can be controlled by setting the hydrogen temperature. Wu et al. proposed various delayed hydrogenation strategies under different conditions based on the control of mass flow rate to meet the requirements of shortening the filling time as much as possible without exceeding the maximum temperature limit.

[0005] In summary, most previous studies have focused on the effects of the filling parameters and structural parameters of the gas cylinder on the temperature rise, pressure and filling rate (SOC) during the filling process, while research on filling strategies is quite limited. Therefore, conducting research on the filling strategy of high-pressure hydrogen storage cylinders and further developing efficient hydrogenation technology are of great significance to improving the safety and economy of high-pressure hydrogen filling. This application uses a numerical simulation method to establish a two-dimensional axisymmetric high-pressure hydrogen storage cylinder model, analyzes the filling process of the high-pressure hydrogen storage cylinder, and further analyzes the sharp drop in temperature during the exhaust process from the perspective of convective heat transfer. Two filling strategies are proposed, namely, by standing or exhausting the method, to achieve the goal of increasing the filling rate while controlling the temperature and pressure, laying the foundation for the safety of hydrogen storage and use. Summary of the invention

[0006] In view of the above problems in the prior art, the purpose of the present invention is to provide a hydrogen rapid filling system, an inerting system and a control method thereof, so as to improve the filling efficiency of high-pressure hydrogen storage cylinders by setting different filling strategies.

[0007] In a first aspect, the present invention provides a hydrogen rapid filling system, comprising a plurality of high-pressure hydrogen cylinders connected in parallel, wherein one end of the plurality of high-pressure hydrogen cylinders connected in parallel is provided with a delivery pipeline connected to a receiving gas cylinder, the other end of the plurality of high-pressure hydrogen cylinders connected in parallel is provided with an input pipeline connected to one end of a compressor, the other end of the compressor is connected to a gas collecting cylinder via a pipeline three, and a pipeline four is connected between the gas collecting cylinder and the receiving gas cylinder; an electromagnetic valve one is provided at the input end of the high-pressure hydrogen cylinder, an electromagnetic valve two is provided at the output end, an electromagnetic valve three is provided on the delivery pipeline, an electromagnetic valve four is provided on pipeline four, and an electromagnetic valve five is provided on the input pipeline.

[0008] In a second aspect, the present invention provides a method for rapid hydrogen filling, comprising the following steps:

[0009] 1) According to the hydrogen storage conditions in each high-pressure gas cylinder, open the solenoid valve 2 in one of the high-pressure hydrogen cylinders and the solenoid valve 3 in the delivery pipeline to inflate the receiving gas cylinder, while the solenoid valve 1, the solenoid valve 4 and the solenoid valve 5 are closed;

[0010] 2) During the inflation process, the opening and closing control time flow of the solenoid valve three is as follows: after the start of 38-40 seconds, close for 23-25 ​​seconds, open for 38-40 seconds, close for 23-25 ​​seconds, open for 38-40 seconds, close for 23-25 ​​seconds, and open the solenoid valve three again until the system displays that the filling is complete.

[0011] The present invention further provides another method for rapid hydrogen filling in a third aspect, comprising the following steps:

[0012] 1) According to the hydrogen storage conditions in each high-pressure gas cylinder, open the solenoid valve 2 in one of the high-pressure hydrogen cylinders and the solenoid valve 3 on the delivery pipeline to inflate the receiving gas cylinder, while the solenoid valve 1, the solenoid valve 4 and the solenoid valve 5 are closed;

[0013] 2) The opening and closing control time flow of solenoid valve 3 and solenoid valve 4 during inflation is as follows:

[0014] Solenoid valve 3 is opened for 38-40 seconds and then closed;

[0015] Solenoid valve 4 is opened for 4-5 seconds and then closed to allow part of the gas in the receiving gas cylinder to enter the gas collecting bottle through pipeline 4;

[0016] Let stand for 7-8 seconds;

[0017] 3) Repeat step 2) twice; control solenoid valve 3 to open and fill for 45 seconds; then close for 7-8 seconds and open again until filling is completed;

[0018] 4) Open solenoid valve 5 and the input end of one of the high-pressure hydrogen bottles is equipped with solenoid valve 1. The hydrogen in the gas collecting bottle is compressed by the compressor and then enters the corresponding high-pressure hydrogen bottle, and the recovery is completed.

[0019] The system of the present invention is multifunctional. In addition to filling hydrogen cylinders, it can also inertate produced hydrogen cylinders filled with air.

[0020] In a fourth aspect, the present invention also provides a hydrogen cylinder rapid inerting system, comprising a plurality of high-pressure nitrogen cylinders connected in parallel, characterized in that one end of the plurality of high-pressure nitrogen cylinders connected in parallel is provided with a delivery pipeline connected to a receiving cylinder, and the receiving cylinder is also connected to a discharge pipeline four; an input end of the high-pressure nitrogen cylinder is provided with an electromagnetic valve one, an output end is provided with an electromagnetic valve two, a delivery pipeline is provided with an electromagnetic valve three, and a discharge pipeline is provided with an electromagnetic valve four.

[0021] The present invention further provides a method for rapid inerting of a hydrogen cylinder in a fifth aspect, characterized in that it comprises the following steps:

[0022] 1) According to the nitrogen storage situation in each high-pressure gas cylinder, open the solenoid valve 2 in one of the high-pressure hydrogen cylinders and the solenoid valve 3 on the delivery pipeline to inflate the receiving gas cylinder. At this time, the solenoid valve 1 and the solenoid valve 4 are closed;

[0023] 2) The opening and closing control time flow of solenoid valve 3 and solenoid valve 4 during inflation is as follows:

[0024] Solenoid valve 3 is opened for 38-40 seconds and then closed;

[0025] Solenoid valve 4 is opened for 4-5 seconds and then closed to discharge part of the gas in the receiving cylinder into the air through pipe 4;

[0026] Let stand for 7-8 seconds;

[0027] 3) Repeat step 2) twice; control solenoid valve 3 to open for filling for 45 seconds; then close for 7-8 seconds and open again until the filling is completed.

[0028] This paper conducts numerical simulation research on the filling process of 35MPa hydrogen storage cylinders, explores the reason for the sharp drop in temperature rise during the exhaust phase in the filling strategy of high-pressure hydrogen storage cylinders, and analyzes the action mechanism of speed and synergy angle; further reveals the influence of two delayed filling strategies on temperature rise, pressure and filling rate in high-pressure hydrogen storage cylinders. The main conclusions are summarized as follows:

[0029] 1) During the filling process of the high-pressure hydrogen storage cylinder, the maximum temperature rise inside the cylinder can be effectively controlled by using the method of static or exhaust. At the beginning of exhaust, the maximum temperature inside the cylinder drops sharply;

[0030] 2) The temperature rise and steep drop phenomenon is the result of the combined influence of the velocity field and the temperature gradient field in the bottle. At the beginning of exhaust, due to the reverse impulse brought by the exhaust, the velocity in the X direction of the bottom area of ​​the bottle shows a trend of first rising and then falling. In the implementation of the third aspect of the present invention, in the time period of 40-40.2s, the circulation velocity field and field coordination degree of the bottom of the bottle increase, and the convective heat transfer effect is enhanced; from the time period of 40.2-41.0s, the velocity in the X direction of the bottom area of ​​the bottle gradually decreases but is still large, the convective heat transfer effect gradually weakens, and the maximum temperature rise in the bottom area of ​​the bottle drops rapidly, eventually forming a steep drop phenomenon.

[0031] (3) Using the mechanism of temperature rise and steep drop, a delayed filling strategy is designed, that is, at a certain time point in the filling process, measures such as standing or venting are taken to allow the hydrogen storage cylinder to cool naturally, and then filling is carried out, and this cycle is repeated many times until the filling of the cylinder is completed. The temperature rises of the two filling methods of the present invention when filling is completed are 54.8℃ and 61.2℃ respectively, and the temperature rises of the two filling methods of the present invention are reduced by 15.7% and 5.8% respectively compared with the existing filling schemes; the average pressure increase rate of the two filling methods of the present invention is significantly reduced compared with the existing filling schemes; the filling rates (SOC) of the two filling methods of the present invention reach 87.33% and 87.36% respectively, and the filling rates of the two filling methods of the present invention are increased by 21.83% and 21.84% respectively compared with the existing filling schemes. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0033] Figure 1 It is a schematic diagram of the hydrogen rapid filling system of the present invention;

[0034] Figure 2 This is a characteristic diagram of the maximum temperature rise change inside the gas cylinder of the present invention;

[0035] Figure 3 This is a graph showing the maximum temperature rise variation within 40-41 seconds of the initial exhaust stage of the gas cylinder of the present invention;

[0036] Figure 4 This is a characteristic diagram of average velocity variation in the X direction of the bottle bottom area of ​​the present invention;

[0037] Figure 5 It is a velocity cloud diagram and a velocity vector diagram of the bottom area of ​​the gas cylinder within 40-41 seconds at the beginning of the exhaust of the gas cylinder of the present invention;

[0038] Figure 6 It is a dimensionless synergistic angle variation characteristic diagram within 40-41s of the initial exhaust stage of the gas cylinder of the present invention;

[0039] Figure 7 It is the synergy angle cloud diagram within 40-41s of the initial exhaust stage of the gas cylinder of the present invention;

[0040] Figure 8 is a graph showing changes in the maximum temperature rise inside the gas cylinder under different filling strategies of the present invention;

[0041] Fig. 9 It is the specific filling method and filling time diagram of the three filling strategies of the present invention;

[0042] Fig.10 It is a temperature cloud diagram within 40-41 seconds of the initial exhaust stage of the gas cylinder of the present invention;

[0043] Fig.11 is a graph showing changes in the average pressure inside the gas cylinder under different filling strategies of the present invention;

[0044] Fig.12 is a graph showing changes in filling rate inside a gas cylinder under different filling strategies of the present invention; DETAILED DESCRIPTION

[0045] Embodiment 1

[0046] The hydrogen quick filling system includes a plurality of high-pressure hydrogen cylinders connected in parallel. In the present embodiment, there are two high-pressure hydrogen cylinders, one end of the two high-pressure hydrogen cylinders connected in parallel is provided with a delivery pipeline connected to a receiving gas cylinder, the other end of the plurality of high-pressure hydrogen cylinders connected in parallel is provided with an input pipeline connected to one end of a compressor, the other end of the compressor is connected to a gas collecting cylinder through a pipeline three, and a pipeline four is connected between the gas collecting cylinder and the receiving gas cylinder; the input end of the high-pressure hydrogen cylinder is provided with an electromagnetic valve one, the output end is provided with an electromagnetic valve two, the delivery pipeline is provided with an electromagnetic valve three, the pipeline four is provided with an electromagnetic valve four, and the input pipeline is provided with an electromagnetic valve five.

[0047] Based on the above device, the present invention proposes a first filling method. The filling steps of scheme 1 are as follows:

[0048] 1) According to the hydrogen storage conditions in each high-pressure gas cylinder, open the solenoid valve 2 in one of the high-pressure hydrogen cylinders and the solenoid valve 3 in the delivery pipeline to inflate the receiving gas cylinder, while the solenoid valve 1, the solenoid valve 4 and the solenoid valve 5 are closed;

[0049] 2) During the inflation process, the opening and closing control time flow of the solenoid valve three is as follows: after the start of 38-40 seconds, close for 23-25 ​​seconds, open for 38-40 seconds, close for 23-25 ​​seconds, open for 38-40 seconds, close for 23-25 ​​seconds, and open the solenoid valve three again until the system displays that the filling is complete.

[0050] Based on the above device, the present invention also proposes a second filling method. The filling steps of scheme 2 are as follows:

[0051] 1) According to the hydrogen storage conditions in each high-pressure gas cylinder, open the solenoid valve 2 in one of the high-pressure hydrogen cylinders and the solenoid valve 3 on the delivery pipeline to inflate the receiving gas cylinder, while the solenoid valve 1, the solenoid valve 4 and the solenoid valve 5 are closed;

[0052] 2) The opening and closing control time flow of solenoid valve 3 and solenoid valve 4 during inflation is as follows:

[0053] Solenoid valve 3 is opened for 38-40 seconds and then closed;

[0054] Solenoid valve 4 is opened for 4-5 seconds and then closed to allow part of the gas in the receiving gas cylinder to enter the gas collecting bottle through pipeline 4;

[0055] Let stand for 7-8 seconds;

[0056] 3) Repeat step 2) twice; control solenoid valve 3 to open and fill for 45 seconds; then close for 7-8 seconds and open again until filling is completed;

[0057] 4) Open solenoid valve 5 and the input end of one of the high-pressure hydrogen bottles is equipped with solenoid valve 1. The hydrogen in the gas collecting bottle is compressed by the compressor and then enters the corresponding high-pressure hydrogen bottle, and the recovery is completed.

[0058] During the rapid filling process of the high-pressure hydrogen storage cylinder, the temperature of hydrogen will continue to rise. When the temperature of hydrogen inside the high-pressure hydrogen storage cylinder is higher than 85°C, the cylinder will be deformed. Therefore, under the nominal working pressure of 35MPa, assuming that the initial pressure of the cylinder is 3MPa, the initial temperature inside the cylinder is 20°C, and the mass flow rate is 19g / s, the following working condition table is designed to study and analyze the temperature rise characteristics of the hydrogen cylinder filling process to verify the creativity of the present invention.

[0059]

[0060] Note: “ ” indicates a non-existent stage, and “√” indicates an existing stage.

[0061] According to national standards, the following requirements should be met when the 35MPa high-pressure hydrogen storage cylinder is filled with hydrogen:

[0062] (1) The internal temperature of the gas cylinder shall not exceed 85°C (temperature rise 65°C).

[0063] (2) The maximum pressure inside the gas cylinder shall not exceed 35MPa.

[0064] (3) The filling rate of gas cylinders should be between 90% and 100% (100% is used as the unified standard in this article). The filling rate is expressed as follows:

[0065]

[0066] Wherein ρ(P, T) is the real-time density of hydrogen at the end of filling, and ρ(NWP, 15°C) is the density of hydrogen at the nominal working pressure (NWP) at a temperature of 15°C, which is 24 g / L.

[0067] Guo Zengyuan et al. conducted a detailed analysis using the two-dimensional flat plate laminar boundary problem as an example, obtained the relationship between the Nusselt number and the temperature gradient vector, and defined the synergy number Fc that characterizes the degree of synergy between the velocity field and the temperature gradient field:

[0068] In the formula, u * is the dimensionless velocity vector, is the dimensionless temperature gradient vector. The larger the field synergy factor Fc is, the better the synergy between the velocity field and the temperature gradient field is.

[0069] The change of the angle (cooperation angle) between the temperature gradient vector and the velocity vector reflects the efficiency of convection diffusion. The cosine value of the angle (cooperation angle) between the temperature gradient vector and the velocity vector is expressed as follows:

[0070]

[0071]

[0072] In the formula, is the velocity vector of the bottom area of ​​the bottle; dc is the discrete element volume of the bottom area of ​​the bottle; is the temperature gradient vector of the bottle bottom area.

[0073] During the filling process of the high-pressure hydrogen storage cylinder, the temperature in the bottle mouth area is the lowest and the temperature in the bottle bottom area is the highest, so the temperature gradient vector points from the bottle mouth area to the bottle bottom area. When the synergy angle is closer to 0°, the direction of the velocity vector and the temperature gradient vector are consistent, the cosine value of the angle (synergy angle) is closer to 1, and the convective heat transfer efficiency is also higher, which intensifies the convective heat transfer from the bottle mouth area to the bottle bottom area, so the bottle bottom area is prone to high temperature areas; when the synergy angle is closer to 180°, the direction of the velocity vector and the temperature gradient vector is opposite, the cosine value of the angle (synergy angle) is closer to -1, and the convective heat transfer efficiency is higher, which intensifies the convective heat transfer from the bottle bottom area to the bottle mouth area, and also weakens the heat conduction from the bottle mouth area to the bottle bottom area, so the bottle bottom area is prone to temperature drop; when the synergy angle is closer to 90°, the cosine value of the angle (synergy angle) between the velocity vector and the temperature gradient vector is closer to 0, and the convective heat transfer efficiency is lower; when the synergy angle is 90°, heat transfer mainly relies on diffusion mechanism.

[0074] The temperature rise change inside the gas cylinder is crucial to the safety of gas cylinder filling. Figure 2 It is the variation characteristic of the maximum temperature rise inside the gas cylinder. Figure 2 It can be seen that the overall change law of the maximum temperature rise of Scheme 1 and Scheme 2 of the present invention is divided into two stages. The first stage is the filling stage, during which the maximum temperature rise of Scheme 1 and Scheme 2 shows an upward trend; the second stage is the static (exhaust) start stage, during which the maximum temperature rise of Scheme 1 and Scheme 2 shows a downward trend, among which Scheme 2 has a steep drop in the maximum temperature rise within 1s after the start of exhaust, that is, between 40 and 41s. The maximum temperature rise of Scheme 2 drops from 42.8℃ to 41.3℃, with a decrease rate of 3.5%; while the maximum temperature rise of Scheme 2 drops from 42.8℃ to 33.2℃, with a decrease rate of 22.4%; the decrease in the maximum temperature rise of Scheme 2 is 6.4 times that of Scheme 1.

[0075] In order to clearly analyze the phenomenon of the maximum temperature rise and steep drop at the beginning of exhaust, a detailed analysis is carried out. Figure 3 It is the maximum temperature rise variation characteristic within 40-41s at the beginning of cylinder exhaust. Figure 3It can be seen that the maximum temperature rise of Scheme 2 decreases fastest at 40.0-40.2s, and then the decrease rate begins to slow down at 40.2-41.0s. In the process of studying the change of the maximum temperature inside the gas cylinder, it is found that in the exhaust start stage of Scheme 2, within 1s after the exhaust starts, that is, between 40-41s, the maximum temperature inside the gas cylinder of Scheme 2 drops sharply at this stage, such as Figure 2 The following takes the time period of 40-41s as an example to analyze the phenomenon of the sudden drop in temperature inside the cylinder at the beginning of exhaust in Scheme 2, as well as the influence of various factors.

[0076] In order to better analyze the influence of the change of speed at the beginning of exhaust on the steep drop of the maximum temperature inside the gas cylinder, the speed change characteristics of the bottom area of ​​the bottle at the beginning of exhaust were further analyzed. Figure 4 is the characteristic curve of the average velocity (VX) in the X direction of the bottom area of ​​the bottle, which is Figure 4 It can be seen that the VX of the original scheme and scheme 1 has been in the speed range of 0.003m / s since the filling stage, and the VX of scheme 2 is also in the speed range of 0.003m / s during the filling stage, but after the exhaust stage of scheme 2, VX shows a trend of first rising and then falling. The peak height value of scheme 2 appears at 40.1s, and the peak height value is 0.8m / s, which is basically consistent with the moment when the maximum temperature inside the gas cylinder drops sharply.

[0077] What is special in the velocity field is that the velocity in the X direction in the bottle is still increasing without adding hydrogen. Through analysis, it is believed that the reverse impulse caused by the exhaust stage causes the velocity in the X direction to increase. Figure 5 The velocity cloud map and the velocity vector map of the bottom area of ​​the gas cylinder within 40-41 seconds at the beginning of the cylinder exhaust are Figure 5 It can be seen that as the exhaust process begins, the flow field structure inside the cylinder of Scheme 2 presents a three-stage distribution from left to right. According to the principle of conservation of momentum, the reverse impulse generated by the high-speed area of ​​the bottle mouth during the exhaust phase is transmitted to the bottom area of ​​the bottle through the middle area of ​​the cylinder, ultimately leading to an increase in the velocity in the bottom area. This indicates that the emergence of the high-speed area and the reflux of the velocity in the bottom area of ​​the bottle strengthen the convective heat transfer effect, causing the maximum temperature inside the cylinder to drop sharply at the beginning of the exhaust phase.

[0078] In addition to the velocity, the factors that affect the convective heat transfer efficiency also depend on the angle between the velocity vector and the temperature gradient vector (cooperation angle). Figure 6 It is a characteristic diagram of the change of the dimensionless coordination angle β (the ratio of the average coordination angle in the bottom area of ​​the bottle to the average coordination angle inside the bottle) within 40-41 seconds at the beginning of the cylinder exhaust. Figure 7 It is the synergy angle cloud diagram within 40-41 seconds of the initial exhaust stage of the cylinder. Figure 6 and Figure 7It can be seen that β increases first and then decreases at the beginning of exhaust. The maximum β of Scheme 2 is 98.8% at 40.12s. In Scheme 2, the proportion of the coordination angle close to 180° in the bottom area increases in the period of 40-40.2s, and its flow field is a ring flow structure (see Figure 5 ), the synergistic effect is good. At this time, due to the reverse impulse caused by the exhaust, the X-direction speed of the bottom area of ​​the bottle increases to the maximum value (see Figure 7 ), so the convective heat transfer effect is the best at this time. From 40.2s to 41.0s, the proportion of the coordination angle close to 0° in the bottom area of ​​the bottle increases, β gradually decreases, and the flow field is a ring flow structure (see Figure 5 ). At this time, the X-direction velocity of the bottom area of ​​the bottle drops rapidly, the convective heat transfer effect gradually weakens, and the maximum temperature of the bottom area drops rapidly and finally forms a steep drop phenomenon. From 41.0s onwards, although there is still circulation at the bottom of the bottle, the X-direction velocity of the bottom area of ​​the bottle is too small, and the convective heat transfer efficiency is poor, so the maximum temperature of the bottom area of ​​the bottle changes little.

[0079] The rapid filling process of high-pressure hydrogen storage cylinders is accompanied by temperature and pressure effects. When the temperature of the hydrogen inside the cylinder exceeds 85°C (i.e., the temperature rise is 65°C) or the hydrogen pressure inside the cylinder exceeds 35MPa, safety issues will be induced. Therefore, during the hydrogen filling process, it is crucial to effectively control the temperature and pressure inside the high-pressure hydrogen storage cylinder. This article studies the strategy of delayed filling, that is, at a certain time point in the filling process, measures such as standing or venting are taken to allow the hydrogen storage cylinder to cool naturally, and then filling is carried out, and this cycle is repeated many times until the cylinder is filled. The schematic diagram of the specific optimized hydrogen filling process is shown below. Figure 1 As shown. The gas collecting bottle uses a 70L empty hydrogen storage bottle, and the exhaust volume of the valve is set to 19g\s.

[0080] Temperature rise change:

[0081] Figure 8 The figure shows the changes in the maximum temperature rise inside the cylinder under three different filling strategies. Figure 8 It can be seen that when the mass flow rate is 19g / s, the original solution requires 165s of filling to fill the hydrogen cylinder. However, due to the temperature limit inside the cylinder, the temperature inside the cylinder has reached 65°C after 115s of filling. If the cylinder continues to be filled with hydrogen at this time, the solid material inside the cylinder will denature, causing safety problems. Therefore, in order to more efficiently control the temperature rise during the hydrogenation process without considering the internal pressure of the cylinder, a method is proposed. Figure 8 In Scheme 1 and Scheme 2, the entire filling process is evenly divided into four parts: 40s, 40s, 40s, and 45s (since Scheme 2 involves the exhaust process, an additional 15s is required later). The specific filling method and time are as follows: Fig. 9 shown.

[0082] from Fig.10 It can also be seen that when the gas cylinder in the original scheme was filled for 115s, the temperature rise inside the gas cylinder exceeded 65°C, while the temperature rise of Scheme 1 and Scheme 2 did not exceed the maximum temperature rise limit of 65°C. This shows that Scheme 1 and Scheme 2 can effectively control the maximum temperature rise inside the gas cylinder. In addition, compared with Scheme 1, Scheme 2 is more time efficient in filling, with an increase of 5.5%. This is because Scheme 2 has an exhaust stage. Within 1s after the exhaust starts, that is, between 40-41s, 93-94s, and 146-147s, the internal temperature of the gas cylinder drops sharply, reducing the static cooling time originally required, as shown below Fig.10 shown. Fig.10 The temperature cloud diagram is shown in the 40-41s period at the beginning of the cylinder exhaust. Fig.10 It can be seen that in the exhaust stage of Scheme 2, the temperature rise dropped by 8°C in just 1 second, effectively controlling the maximum temperature rise in the bottle.

[0083] Pressure changes:

[0084] Fig.11 The figure shows the changes in the average pressure inside the cylinder under three different filling strategies. Fig.11 It can be seen that without considering the temperature rise of the gas cylinder, the hydrogen storage cylinder in the original scheme needs to be filled with hydrogen for 165s. However, due to the average pressure inside the gas cylinder, the average pressure inside the gas cylinder rises to 35MPa when the hydrogen storage cylinder is filled for 145s. The average pressure inside the gas cylinder of Scheme 1 and Scheme 2 rises to 35MPa when the filling is 221s and 199s respectively. This shows that the rate of increase of the average pressure inside the gas cylinder in Scheme 1 and Scheme 2 is significantly lower than that in the original scheme.

[0085] Filling rate:

[0086] During the filling process of the high-pressure hydrogen storage cylinder, the filling rate (SOC) inside the cylinder is low due to the dual restrictions of the internal pressure and temperature of the cylinder. Therefore, it is hoped to achieve the purpose of increasing the filling rate (SOC) by standing and exhausting. According to the analysis of the maximum temperature rise and the average pressure in the bottle, when the mass flow rate is 19g / s, the filling time of Scheme 1 and Scheme 2 is longer than that of the original scheme, so their filling rate (SOC) is also increasing.

[0087] The changes of the internal filling rate (SOC) of the gas cylinder under three different filling strategies are shown in the following table and Fig.11As shown in the figure, when the mass flow rate is 19g / s, the hydrogen storage cylinder in the original scheme needs to be filled with hydrogen for 165s. However, due to the limitation of the internal temperature of the cylinder, the temperature rise inside the cylinder has reached 65℃ when the hydrogen storage cylinder is filled for 115s. At this time, the internal filling rate (SOC) of the cylinder of the original scheme reaches 71.7%. When Scheme 1 and Scheme 2 are filled for 221s and 199s respectively, the internal temperature rise of the cylinder does not reach 65℃ due to the limitation of the average pressure and temperature inside the cylinder, while the average pressure has risen to 35MPa. At this time, the internal filling rate (SOC) of the cylinder of Scheme 1 and Scheme 2 reaches 87.33% and 87.36% respectively. The filling rates of Scheme 1 and Scheme 2 are increased by 21.83% and 21.84% respectively compared with the original scheme. In addition, compared with Scheme 1, Scheme 2 has a higher time efficiency of filling, which is increased by 10%.

[0088]

[0089] Note: “ ” indicates that the threshold value is not reached, and “√” indicates that the threshold value is reached.

[0090] Embodiment 2

[0091] The system of the present invention is multifunctional. In addition to filling hydrogen cylinders, it can also inertate produced hydrogen cylinders filled with air.

[0092] A rapid inerting system for hydrogen cylinders comprises a plurality of high-pressure nitrogen cylinders connected in parallel, wherein one end of the plurality of high-pressure nitrogen cylinders connected in parallel is provided with a delivery pipeline connected to a receiving cylinder, and the receiving cylinder is also connected to a discharge pipeline four; an input end of the high-pressure nitrogen cylinder is provided with a solenoid valve one, an output end is provided with a solenoid valve two, the delivery pipeline is provided with a solenoid valve three, and the discharge pipeline four is provided with a solenoid valve four.

[0093] A method for rapid inerting of a hydrogen cylinder based on the above device comprises the following steps:

[0094] 1) According to the nitrogen storage situation in each high-pressure gas cylinder, open the solenoid valve 2 in one of the high-pressure hydrogen cylinders and the solenoid valve 3 on the delivery pipeline to inflate the receiving gas cylinder. At this time, the solenoid valve 1 and the solenoid valve 4 are closed;

[0095] 2) The opening and closing control time flow of solenoid valve 3 and solenoid valve 4 during inflation is as follows:

[0096] Solenoid valve 3 is opened for 38-40 seconds and then closed;

[0097] Solenoid valve 4 is opened for 4-5 seconds and then closed to discharge part of the gas in the receiving cylinder into the air through pipe 4;

[0098] Let stand for 7-8 seconds;

[0099] 3) Repeat step 2) twice; control solenoid valve 3 to open for filling for 45 seconds; then close for 7-8 seconds and open again until the filling is completed.

[0100] The principle of this embodiment is the same as that of Embodiment 1 and will not be described again here.

[0101] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A hydrogen rapid filling system, comprising a plurality of high-pressure hydrogen cylinders connected in parallel, characterized in that: One end of the multiple high-pressure hydrogen cylinders connected in parallel is provided with a delivery pipeline connected to a receiving gas cylinder, and the other end of the multiple high-pressure hydrogen cylinders connected in parallel is provided with an input pipeline connected to one end of a compressor. The other end of the compressor is connected to a gas collecting bottle through pipeline three, and pipeline four is connected between the gas collecting bottle and the receiving gas cylinder.

2. The hydrogen rapid filling system according to claim 1, characterized in that: The input end of the high-pressure hydrogen cylinder is provided with a solenoid valve 1, the output end is provided with a solenoid valve 2, the delivery pipeline is provided with a solenoid valve 3, the pipeline 4 is provided with a solenoid valve 4, and the input pipeline is provided with a solenoid valve 5.

3. A method for rapid filling using the hydrogen rapid filling system as claimed in claim 2, characterized in that: The following steps are included: 1) According to the hydrogen storage conditions in each high-pressure gas cylinder, open the solenoid valve 2 in one of the high-pressure hydrogen cylinders and the solenoid valve 3 in the delivery pipeline to inflate the receiving gas cylinder, while the solenoid valve 1, the solenoid valve 4 and the solenoid valve 5 are closed; 2) During the inflation process, the opening and closing control time flow of the solenoid valve three is as follows: after the start of 38-40 seconds, close for 23-25 ​​seconds, open for 38-40 seconds, close for 23-25 ​​seconds, open for 38-40 seconds, close for 23-25 ​​seconds, and open the solenoid valve three again until the system displays that the filling is complete.

4. A method for rapid filling using the hydrogen rapid filling system as claimed in claim 2, characterized in that: The following steps are included: 1) According to the hydrogen storage conditions in each high-pressure gas cylinder, open the solenoid valve 2 in one of the high-pressure hydrogen cylinders and the solenoid valve 3 on the delivery pipeline to inflate the receiving gas cylinder, while the solenoid valve 1, the solenoid valve 4 and the solenoid valve 5 are closed; 2) The opening and closing control time flow of solenoid valve 3 and solenoid valve 4 during inflation is as follows: Solenoid valve 3 is opened for 38-40 seconds and then closed; Solenoid valve 4 is opened for 4-5 seconds and then closed to allow part of the gas in the receiving gas cylinder to enter the gas collecting bottle through pipeline 4; Let stand for 7-8 seconds; 3) Repeat step 2) twice; control solenoid valve 3 to open and fill for 45 seconds; then close for 7-8 seconds and open again until filling is completed; 4) Open solenoid valve 5 and the input end of one of the high-pressure hydrogen bottles is equipped with solenoid valve 1. The hydrogen in the gas collecting bottle is compressed by the compressor and then enters the corresponding high-pressure hydrogen bottle, and the recovery is completed.

5. A hydrogen cylinder rapid inerting system, comprising a plurality of high-pressure nitrogen cylinders connected in parallel, characterized in that: One end of multiple high-pressure nitrogen cylinders connected in parallel is provided with a delivery pipeline connected to a receiving gas cylinder, and the receiving gas cylinder is also connected to a discharge pipeline four; the input end of the high-pressure nitrogen cylinder is provided with a solenoid valve one, the output end is provided with a solenoid valve two, the delivery pipeline is provided with a solenoid valve three, and the discharge pipeline four is provided with a solenoid valve four.

6. A method for rapid inerting using the hydrogen cylinder rapid inerting system as claimed in claim 5, characterized in that: The following steps are included: 1) According to the nitrogen storage situation in each high-pressure gas cylinder, open the solenoid valve 2 in one of the high-pressure hydrogen cylinders and the solenoid valve 3 on the delivery pipeline to inflate the receiving gas cylinder. At this time, the solenoid valve 1 and the solenoid valve 4 are closed; 2) The opening and closing control time flow of solenoid valve 3 and solenoid valve 4 during inflation is as follows: Solenoid valve 3 is opened for 38-40 seconds and then closed; Solenoid valve 4 is opened for 4-5 seconds and then closed to discharge part of the gas in the receiving cylinder into the air through pipe 4; Let stand for 7-8 seconds; 3) Repeat step 2) twice; control solenoid valve 3 to open for filling for 45 seconds; then close for 7-8 seconds and open again until the filling is completed.

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