A sampling method of a high-pressure fuel hydrogen online sampling system

Abstract

The application discloses a sampling method of a high-pressure fuel hydrogen online sampling system. Fuel hydrogen flows into a sampling pipe, and then is subjected to stepwise pressure reduction, stable pressure and temperature control, and sampling. Another part of the fuel hydrogen is discharged through a pipeline connected with exhaust. The stepwise pressure reduction of the fuel hydrogen includes first fuel hydrogen pressure reduction, first fuel hydrogen pressure stabilization and temperature control, second fuel hydrogen pressure reduction, and second fuel hydrogen pressure stabilization and temperature reduction. The cooling water after the second fuel hydrogen temperature reduction is used for the first fuel hydrogen temperature control. The online sampling system can be applied to fuel hydrogen with a temperature in the range of 25 DEG C to 50 DEG C, and the temperature of the sample hydrogen gas at the sampling port is controlled in the range of 20 DEG C to 36 DEG C after the fuel hydrogen in the system is cooled.

Description

Technical Field

[0001] This invention relates to the field of gas sampling technology, and more specifically to a sampling method for a high-pressure fuel hydrogen online sampling system. Background Technology

[0002] Currently, the hydrogen energy industry is developing rapidly both domestically and internationally. Hydrogen refueling stations are a crucial link in the industrial chain. The quality of hydrogen has a close relationship with the operating efficiency and lifespan of hydrogen compressors and fuel cells. Strict purity control is required throughout the processes of hydrogen production, purification, compression at refueling stations, and refueling. At refueling stations, regular sampling and testing of fuel hydrogen is necessary, placing extremely high demands on equipment performance. Fuel hydrogen sampling and testing technologies largely rely on imported equipment, which is expensive and its core technology is difficult to master. Therefore, developing a domestically produced online fuel hydrogen sampling system is extremely important.

[0003] Existing hydrogen refueling stations operate at pressures as high as 70 MPa. During fuel hydrogen sampling, the equipment must possess high-pressure resistance and safety features. The sampling process requires pressure reduction of the fuel hydrogen, which inevitably leads to a decrease in the stability of the sampling system and an increase in the temperature of the hydrogen gas and pressure-reducing valve components within the pipeline, especially pronounced during high-pressure fuel hydrogen sampling. Decreased stability of the sampling system directly affects its safety; while increased temperature of the hydrogen gas and pressure-reducing valve components within the pipeline affects not only the safety of the sampling system but also the authenticity of the sample.

[0004] In high-pressure environments, continuous sampling using online sampling systems raises significant safety concerns. Firstly, the high pressure necessitates minimizing pressure drop during decompression to ensure system stability. Secondly, it requires simultaneous control and reduction of temperature rise in both the hydrogen gas and pressure-reducing valve components within the system's pipelines. Since online sampling systems operate continuously, the temperature fluctuations of hydrogen gas within the pipelines are greater than during single sampling. Thirdly, the environment in which the online sampling system operates further influences the hydrogen temperature, especially during hot summer months, leading to further temperature increases in both the hydrogen gas and pressure-reducing valve components. Therefore, temperature and pressure drop control are crucial in online sampling systems. Designing a high-pressure online fuel hydrogen sampling system that meets the requirements of safety, sample authenticity, and system practicality is an urgent problem to be solved. Summary of the Invention

[0005] This invention addresses the problems in existing technologies by disclosing a high-pressure fuel hydrogen online sampling system. This system is applicable to high-pressure fuel hydrogen environments (35 MPa-100 MPa). It addresses the technical difficulties in continuous sampling of existing online sampling systems by simultaneously controlling the pressure drop, the hydrogen temperature in the gas pipe, and the temperature of the pressure-reducing valve components during the sampling process. This improves the stability of the online sampling system during high-pressure fuel hydrogen sampling, ensures that the sampled fuel hydrogen temperature is within the standard range, and controls the temperature variation of the pressure-reducing valve components. This invention not only solves the safety issues of online sampling systems but also further ensures the authenticity of the fuel hydrogen samples.

[0006] This invention is achieved through the following technical solution:

[0007] This invention provides an online high-pressure fuel hydrogen sampling system, which includes an injection zone, a depressurization and cooling zone, an exhaust zone, and a sampling zone.

[0008] In the hydrogen flow path, the sample injection section, the decompression and cooling section, and the exhaust section are connected in series.

[0009] The sampling interval is connected in parallel with the pressure reduction and cooling interval;

[0010] The pressure reduction and cooling zone includes a pressure reducing valve, a cooling and flow stabilizing device, a pressure reducing valve, and a cooling and flow stabilizing device.

[0011] In the hydrogen flow path, the No. 1 pressure reducing valve, the No. 1 cooling and flow stabilizing device, the No. 2 pressure reducing valve, and the No. 2 cooling and flow stabilizing device are connected in series.

[0012] The first cooling and stabilizing device is also connected to the second cooling and stabilizing device via a cooling pipe.

[0013] The above-described design of this invention, through the coordinated operation of the No. 1 pressure reducing valve, the No. 1 cooling and flow stabilizing device, the No. 2 pressure reducing valve, and the No. 2 cooling and flow stabilizing device, achieves a step-wise pressure drop of high-pressure fuel hydrogen while effectively reducing the temperature of the hydrogen in the gas pipe and controlling a large-scale temperature rise of the pressure reducing valve. The No. 1 and No. 2 pressure reducing valves enable a step-wise decrease in the pressure of the fuel hydrogen in the gas pipe. Through their coordinated operation, not only is the vibration of the pressure reducing valve reduced, but the significant temperature rise of the pressure reducing valve during the pressure drop process is also controlled. This improves both the stability and safety of the entire sampling system. The No. 1 pressure reducing valve and the No. 1 cooling and flow stabilizing device work together so that when the hydrogen in the gas pipe passes through the No. 1 pressure reducing valve, not only will the temperature rise, but the volume of the hydrogen will also expand. The No. 1 cooling and flow stabilizing device can buffer the fuel hydrogen after the first stage of pressure reduction, improve the stability of the system, and also control the temperature of the hydrogen in the gas pipe. The cooperation between the No. 1 pressure reducing valve and the No. 1 cooling and flow stabilizing device helps to improve the stability and safety of the sampling system, while promoting a second pressure reduction of hydrogen with more stable pressure and temperature, thus laying the foundation for the second stable pressure reduction process of hydrogen. With the cooperation of pressure reducing valve No. 2 and cooling and stabilizing device No. 2, hydrogen gas after passing through cooling and stabilizing device No. 1 enters pressure reducing valve No. 2 for a second pressure reduction. Cooling and stabilizing device No. 2 buffers the fuel hydrogen after passing through pressure reducing valve No. 2, improving system stability while cooling the hydrogen temperature in the gas pipe, ensuring the final temperature of the fuel hydrogen remains within the standard range. The cooperation of pressure reducing valve No. 2 and cooling and stabilizing device No. 2 facilitates the stable completion of the stepped pressure reduction process of high-pressure fuel hydrogen and the reduction of hydrogen temperature in the gas pipe during the pressure reduction process, thereby improving the stability and safety of the entire system. The cooperation of cooling and stabilizing devices No. 1 and No. 2 achieves staged stabilization of hydrogen pressure while controlling and reducing the hydrogen temperature in the gas pipe. This not only ensures the stable pressure drop of hydrogen during the stepped pressure reduction process but also ultimately reduces the temperature of the fuel hydrogen in the gas pipe, thus improving the safety of the entire sampling process and ensuring the authenticity of the fuel hydrogen sample.

[0014] As a further embodiment, the sampling system also includes a safety zone; the safety zone is connected in parallel with the decompression and cooling zone.

[0015] As a further embodiment, the first cooling and flow stabilizing device includes a first fuel hydrogen cooling channel and a first fuel hydrogen pressure stabilizing channel, with the first fuel hydrogen cooling channel surrounding the first fuel hydrogen pressure stabilizing channel to form a first sealed cavity; the second cooling and flow stabilizing device includes a second fuel hydrogen cooling channel and a second fuel hydrogen pressure stabilizing channel, with the second fuel hydrogen cooling channel surrounding the second fuel hydrogen pressure stabilizing channel to form a second sealed cavity; the first fuel hydrogen cooling channel of the first cooling and flow stabilizing device is also connected to the second fuel hydrogen cooling channel of the second cooling and flow stabilizing device via a cooling pipe. The first fuel hydrogen cooling channel controls the temperature of the hydrogen in the first fuel hydrogen pressure stabilizing channel, and the first fuel hydrogen pressure stabilizing channel buffers the hydrogen after it has been depressurized by the first pressure reducing valve. Thus, the first cooling and flow stabilizing device simultaneously achieves buffering of fuel hydrogen pressure and control of fuel hydrogen temperature. The No. 2 fuel hydrogen cooling channel lowers the temperature of the hydrogen in the No. 2 fuel hydrogen pressure stabilization channel. The No. 2 fuel hydrogen pressure stabilization channel also buffers the hydrogen after it has been depressurized by the No. 2 pressure reducing valve. The No. 2 cooling and flow stabilization device simultaneously buffers the fuel hydrogen pressure and lowers its temperature. The connection between the No. 1 and No. 2 fuel hydrogen cooling channels, within the same cooling pipe, allows for the initial control and subsequent reduction of hydrogen temperature during the step-wise depressurization process. This achieves stable depressurization of the hydrogen while simultaneously lowering the temperature of the hydrogen within the pipe, thereby improving the stability and safety of the sampling system and the authenticity of the final sample. Furthermore, it makes full use of cooling water, reducing costs.

[0016] As a further embodiment, the first fuel hydrogen pressure stabilizing channel is a coiled first spiral pipe; the second fuel hydrogen pressure stabilizing channel is a coiled second spiral pipe.

[0017] The first spiral conduit is a 3 / 8 inch seamless conduit; the second spiral conduit is a 3 / 8 inch seamless conduit.

[0018] The curvature of the first and second spiral pipes is not less than the minimum bending radius;

[0019] The wall thickness of the No. 1 spiral pipe and the No. 2 spiral pipe shall not be less than 3mm;

[0020] The diameter of the hydrogen flow through the No. 1 spiral pipe and the No. 2 spiral pipe is not less than 9.5 mm;

[0021] The diameter of the first spiral pipe is not less than 200 mm and the diameter of the second spiral pipe is not less than 200 mm;

[0022] The length of the first spiral conduit is h1, and the length of the second spiral conduit is h2.

[0023]

[0024]

[0025] in:

[0026] A1 and A2 are the heat transfer areas (m²) of spiral pipe No. 1 and spiral pipe No. 2, respectively. 2 ); d1 and d2 are the diameters (mm) of hydrogen flow through the first spiral pipe and the second spiral pipe, respectively.

[0027] The length of the first sealed cavity is not less than 1.5 times the diameter of the first spiral pipe; the height of the first sealed cavity is not less than 1.5 times the diameter of the first spiral pipe; the volume of the first sealed cavity meets the pressure requirements of the cooling water circulation.

[0028] The length of the second sealed cavity is not less than 1.5 times the diameter of the second spiral pipe; the height of the second sealed cavity is not less than 1.5 times the diameter of the second spiral pipe; the volume of the second sealed cavity meets the pressure requirements of the cooling water circulation.

[0029] The height ratio of the second sealed cavity to the first sealed cavity is 2:3, that is, the design volume ratio of the sealed cavities with the same diameter is 2:3.

[0030] The length, wall thickness, and diameter of both the No. 1 and No. 2 spiral pipes are related to the heat transfer area of ​​the heat exchange. By controlling the pipes, the heat exchange area when hydrogen flows through the circulating cooling device can be further controlled. The diameters of the No. 1 and No. 2 spiral pipes, and the size of the cavity of the circulating cooling device, are related to the volume of cooling water flowing through. By controlling the flow of cooling water through the cavity, the cooling rate and temperature change can be controlled. Under these conditions, the No. 1 cooling and stabilizing device can control the hydrogen temperature reduction range of 2℃-15℃, and the No. 2 cooling and stabilizing device can control the hydrogen temperature reduction range of no less than 5℃-20℃. The No. 2 cooling and stabilizing device reduces the hydrogen temperature more significantly than the No. 1 device. Specifically, the No. 2 cooling and stabilizing device mainly stabilizes and cools the hydrogen after the No. 2 pressure reducing valve. The pressure drop of the No. 2 pressure reducing valve is greater and is the main pressure drop process in the sampling system; therefore, the cooling range of the No. 2 cooling and stabilizing device is larger. The No. 1 cooling and stabilizing device mainly reduces the pressure and controls the temperature of the hydrogen after the No. 1 pressure reducing valve. The No. 1 pressure reducing valve first applies a small gradient pressure reduction to the hydrogen in the sampling system. If a large gradient pressure reduction is applied at the beginning, it will affect the stability of the sampling system. Therefore, the pressure drop of the No. 1 pressure reducing valve is smaller. The No. 1 cooling and stabilizing device mainly stabilizes the temperature of the hydrogen after the No. 1 pressure reducing valve and can reduce the temperature of the hydrogen within a small range.

[0031] As a further step, A1 and A2 are:

[0032]

[0033] in:

[0034] Q is the heat transfer rate (J / s); U is the heat transfer coefficient (J / m²). 2 ·s·℃); △T is the average temperature difference (℃);

[0035]

[0036] in:

[0037] T h1 T represents the temperature (°C) of the hot fluid before cooling. h2 Temperature (°C) of the hot fluid after cooling; T c1 T represents the temperature (°C) of the cold fluid before heating. c2 Temperature (°C) of the cold fluid after heating; Th1-Th2 is not less than 5°C;

[0038]

[0039] in:

[0040] h i The heat transfer coefficient of the inner surface of the spiral heat exchanger (J / m) 2 ·s·℃); h o The heat transfer coefficient of the outer surface of the spiral heat exchanger (J / m) 2 ·s·℃); δ is the wall thickness of the spiral heat exchanger tube (m); λ is the thermal conductivity of the tube material (J / m·s·℃); ki and ko are the reciprocals of the thermal resistance of the scale layer inside and outside the tube, respectively (k is the reciprocal of the thermal resistance of the scale layer when there is no scale layer). i k o Both are 1)(J / m 2 ·s·℃); For the overall efficiency of the ribbed surface (if the outer surface is ribbed, then...) ); This is the ratio of the outer surface area to the inner surface area of ​​the heat exchange tube. Using these parameters, the required length of the hydrogen pipeline can be further calculated based on the range of temperature to be cooled and the heat transfer coefficient of the hydrogen pipeline. This allows for obtaining more suitable lengths for the first and second spiral pipelines in this invention, thus improving the stability and safety of the sampling system.

[0041] As a further embodiment, the injection zone includes an injection port, a high-pressure needle valve, and a flow stabilizing tube; in the hydrogen flow path, the injection port, the high-pressure needle valve, and the flow stabilizing tube are connected in series.

[0042] As a further option, the flow stabilizing pipe is connected to the No. 1 pressure reducing valve. The cooperation between the flow stabilizing pipe and the No. 1 pressure reducing valve helps stabilize the pressure of hydrogen flowing into the sampling system from the filling port, thus preparing for the stable decompression and cooling processes of the hydrogen, and improving the stability and safety of the entire system.

[0043] As a further option, the flow stabilizing pipe is a 3 / 8-inch seamless pipe;

[0044] The wall thickness of the flow stabilizing pipe is not less than 3mm;

[0045] The diameter of the current stabilizing tube is not less than 9.5 mm;

[0046] The bending radius of the flow stabilizing tube is not less than 200mm;

[0047] The length of the flow stabilizing tube is not less than 1.8m. The flow stabilizing tube helps to stabilize the high-pressure fuel hydrogen entering the sampling system, thus facilitating the step-by-step pressure drop and cooling of the fuel hydrogen.

[0048] As a further embodiment, the pressure reduction and cooling zone also includes an inlet, an outlet, an inlet pipe, and an outlet pipe; the inlet pipe connects the inlet to the second cooling and flow stabilizing device; the outlet pipe connects the outlet to the first cooling and flow stabilizing device; and a control valve is installed on the inlet pipe. Through the above design, the cooling water after heat exchange in the second cooling and flow stabilizing device flows into the first cooling and flow stabilizing device to stabilize the temperature of the hydrogen in the first device, thus achieving full utilization of resources. Furthermore, by adjusting the control valve to control the flow rate of the cooling water in the first and second cooling and flow stabilizing devices, the efficiency of heat exchange can be adjusted. Ultimately, it can be successfully achieved that the cooling water flowing from the first to the second cooling and flow stabilizing device can not only control the hydrogen temperature but also further reduce the temperature of the hydrogen in the first cooling and flow stabilizing device.

[0049] As a further embodiment, the pressure reduction and cooling zone also includes a first thermometer, a second thermometer, a pressure gauge, and a sampling needle valve. The first thermometer is positioned between the second pressure reducing valve and the second cooling and flow stabilizing device. The second thermometer is positioned between the second cooling and flow stabilizing device and the pressure gauge. The pressure gauge is positioned between the second thermometer and the sampling needle valve. Along the hydrogen flow path, the second cooling and flow stabilizing device, the second thermometer, the pressure gauge, and the sampling needle valve are sequentially arranged. The first and second thermometers directly reflect the hydrogen temperature after passing through the first and second cooling and flow stabilizing devices, and can directly indicate whether the efficiency of heat exchange control within these devices is appropriate.

[0050] As a further embodiment, the exhaust zone includes a flame arrester and an vent; the flame arrester and the vent are connected in series along the hydrogen flow path; an exhaust pipe is provided between the flame arrester and the sampling needle valve. The flame arrester installed at the vent is used to prevent the flame of flammable gas and flammable liquid vapor from spreading to the safety device, which can further improve the safety of the sampling system.

[0051] As a further embodiment, the safety zone includes a venting needle valve, a first safety valve, and a second safety valve. The venting needle valve is positioned between the first cooling and flow stabilizing device and the second pressure reducing valve. The first safety valve is positioned between the second pressure reducing valve and the second cooling and flow stabilizing device. The second safety valve is positioned between the second cooling and flow stabilizing device and the second thermometer. The venting needle valve, the first safety valve, and the second safety valve are connected in parallel to the exhaust pipe between the sampling needle valve and the flame arrester. This design allows for the discharge of hydrogen from the sampling system through the coordinated operation of the valves. When the first inlet pressure gauge or the first outlet pressure gauge on the first pressure reducing valve malfunctions, the venting needle valve can be opened to quickly release the hydrogen from the pipeline. The first safety valve is used to discharge hydrogen between the second pressure reducing valve and the second cooling and flow stabilizing device. The second safety valve is used to discharge hydrogen between the second cooling and flow stabilizing device and the second thermometer. This coordinated operation of the valves enhances the safety of the pressure reducing and cooling zone.

[0052] As a further embodiment, the exhaust pipeline includes a venting needle valve; in the hydrogen flow path, the venting needle valve is located at the connection point between the sampling needle valve and the sampling needle valve on the exhaust pipeline between the venting needle valve, the first safety valve, and the second safety valve, which are connected in parallel.

[0053] As a further embodiment, the sampling area includes a sampling cylinder group. The inlet of the sampling cylinder group is connected between the venting needle valve and the sampling needle valve on the exhaust pipe. The outlet of the sampling cylinder group is connected via a gas exchange pipe to the middle of the connection point on the exhaust pipe between the sampling needle valve and the flame arrester, after the exhaust pipe is connected in parallel with the flame arrester, the relief needle valve, the first safety valve, and the second safety valve.

[0054] As a further embodiment, the ventilation pipeline includes a one-way valve.

[0055] As a further embodiment, the sampling cylinder assembly includes a cylinder inlet needle valve, a cylinder pressure gauge, a sampling cylinder, and a cylinder outlet needle valve; in the hydrogen flow path, the cylinder inlet needle valve, the cylinder pressure gauge, the sampling cylinder, and the cylinder outlet needle valve are connected in series.

[0056] As a further embodiment, the first pressure reducing valve includes a first inlet pressure gauge and a first outlet pressure gauge; the second pressure reducing valve includes a second inlet pressure gauge and a second outlet pressure gauge.

[0057] As a further option, the set relief pressure limit of the first safety valve includes one of the options i-iii:

[0058] i-solution:

[0059] When the pressure at the filling port is 35 MPa, the first safety valve is set to release pressure limit of 35 MPa-44 MPa.

[0060] Option ii:

[0061] When the pressure at the filling port is 75 MPa, the first safety valve is set to release pressure limit of 75 MPa-85 MPa.

[0062] Option iii:

[0063] When the pressure at the filling port is 90 MPa, the first safety valve is set to release pressure limit of 90 MPa-100 MPa.

[0064] The set pressure limit for the No. 1 safety valve shall not exceed the set pressure of the safety valve. The specific overpressure relief pressure value of the safety valve shall be set according to specific requirements and sealed for confirmation when the equipment is manufactured and shipped. It shall not be changed by the user.

[0065] As a further option, the second safety valve is set to release pressure limit of 10 MPa-15 MPa.

[0066] As a further option, the working pressure of both the No. 1 pressure reducing valve and the No. 2 pressure reducing valve can meet the working conditions of 0-15000psig.

[0067] As a further option, the hardware, valves, pipelines, and joints in the sampling system can all operate at pressures ranging from 0 to 15000 psi g, ensuring the safety and stability of the system.

[0068] As a further solution, the valves, pipelines, and hardware facilities in the sampling system undergo inert passivation treatment. This helps extend the service life of the sampling system.

[0069] As a further embodiment, the pressure of the first inlet pressure gauge is 35 MPa-90 MPa; the pressure of the first outlet pressure gauge is 25 MPa-55 MPa; the pressure of the second inlet pressure gauge of the second pressure reducing valve is 25 MPa-55 MPa; the pressure of the second outlet pressure gauge is 2 MPa-10 MPa; and the flow rate of the cooling water in the first cooling and flow stabilizing device is 0.5 m³ / h. 3 / h-3.5m 3 / h; the flow rate of cooling water in the second cooling and stabilizing device is 0.5m³ / h. 3 / h-3.5m 3The cooling water temperature in the first cooling and flow stabilizing device is 35℃-45℃; the cooling water temperature in the second cooling and flow stabilizing device is 15℃-30℃; the cooling water temperature at the inlet is 5℃-10℃; the hydrogen temperature at the first inlet pressure gauge is 30℃-45℃; the hydrogen flow rate in the first cooling and flow stabilizing device is 7m / sec-12m / sec; and the hydrogen flow rate in the second cooling and flow stabilizing device is 7m / sec-9m / sec. By controlling the above parameters in the online sampling system, this invention can ensure a stable and continuous sampling process, and the temperature of the sample hydrogen taken from the outlet of the sampling system can be between 20℃ and 36℃, and the pressure of the sample hydrogen can be between 2MPa and 10MPa. This improves the stability and safety of the online sampling system and ensures the authenticity of the sampled product data.

[0070] The present invention also provides a method for sampling fuel hydrogen using the sampling system, the method comprising:

[0071] Fuel hydrogen is injected through a gas tube, and then the fuel hydrogen is subjected to step-by-step depressurization while the pressure and temperature of the fuel hydrogen after step-by-step depressurization are stabilized. Then, a portion of the fuel hydrogen is sampled, and the other portion of the fuel hydrogen is discharged through a pipeline connected to the exhaust.

[0072] The step-by-step pressure reduction of fuel hydrogen includes the first fuel hydrogen pressure reduction, the first fuel hydrogen pressure stabilization and temperature control, the second fuel hydrogen pressure reduction, and the second fuel hydrogen pressure stabilization and temperature reduction.

[0073] The cooling water from the second cooling of the fuel hydrogen is used for the first fuel hydrogen temperature control.

[0074] The method of this invention achieves step-by-step depressurization of high-pressure fuel hydrogen while simultaneously controlling and cooling the hydrogen gas during the step-by-step depressurization process. This ensures that the entire sampling system is in a stable sampling state and that fuel hydrogen samples with temperatures within the standard range are obtained. The combined effect of the first and second fuel hydrogen depressurization steps facilitates step-by-step depressurization of the fuel hydrogen in the sampling system. This not only reduces vibration during the depressurization process but also controls the significant temperature rise of the depressurization components due to pressure drop, thus contributing to the stability and safety of the sampling system. The combined effect of the first fuel hydrogen depressurization and the first fuel hydrogen pressure stabilization and temperature control allows for control of the hydrogen pressure and temperature after the first depressurization. This improves the stability of the sampling system and ensures that the hydrogen gas maintains a stable pressure and temperature after the first depressurization, thus facilitating the second depressurization process. This further enhances the stability and safety of the sampling system and lays the foundation for the second fuel hydrogen depressurization process. With the combined effects of the second fuel hydrogen depressurization and the second fuel hydrogen pressure stabilization and cooling, the hydrogen gas after the second depressurization was stabilized in pressure and cooled, successfully improving the stability and safety of the entire sampling system and also achieving the temperature reduction of the fuel hydrogen. The combined effect of the first fuel hydrogen pressure stabilization and temperature control with the second fuel hydrogen pressure stabilization and cooling achieved a step-by-step pressure stabilization process while simultaneously controlling and reducing the temperature of the hydrogen gas. This not only improved the stability of the hydrogen gas during the step-by-step depressurization process but also effectively controlled and reduced the temperature of the fuel hydrogen.

[0075] As a further option, fuel hydrogen subjected to step-down depressurization can flow into a safe zone before being discharged.

[0076] As a further step, any residual fuel hydrogen after sampling can also be discharged.

[0077] As a further embodiment, the fuel hydrogen undergoing the stepped pressure reduction can flow into the safety zone through at least three branches; the first branch is used to drain the fuel hydrogen between the completion of the first fuel hydrogen pressure stabilization and temperature control and before the second fuel hydrogen pressure reduction; the second branch is used to drain the fuel hydrogen between the completion of the second fuel hydrogen pressure reduction and before the second fuel hydrogen pressure stabilization and cooling; the third branch is used to drain the fuel hydrogen after the completion of the second fuel hydrogen pressure stabilization and cooling; the three branches are connected to the same gas path exiting the safety zone, and the fuel hydrogen exiting the safety zone flows into the pipeline connected to the exhaust after the second fuel hydrogen pressure stabilization and cooling, and is then discharged.

[0078] As a further measure, a portion of the fuel hydrogen that has undergone the second fuel hydrogen stabilization and cooling process is sampled, while the remaining portion, along with the fuel hydrogen from the safety zone, flows into the pipeline connected to the exhaust gas after the second fuel hydrogen stabilization and cooling process, and is then discharged together.

[0079] As a further option, the residual fuel hydrogen after sampling can be combined with the fuel hydrogen flowing from the safe zone into the pipeline connected to the exhaust after the second fuel hydrogen stabilization and cooling process, and then discharged together.

[0080] As a further embodiment, the sampling temperature of the fuel hydrogen in the sampling system is 20℃-36℃; the pressure of the fuel hydrogen during the injection of the sampling system is 35MPa-90MPa; and the pressure of the fuel hydrogen during the sampling is 2MPa-10MPa.

[0081] As a further improvement, the temperature range during the first fuel hydrogen pressure stabilization and temperature control is 2℃ to 15℃; the temperature range during the second fuel hydrogen pressure stabilization and temperature reduction is 5℃ to 20℃.

[0082] As a further refinement, the flow rate of fuel hydrogen during the first fuel hydrogen pressure stabilization and temperature control is 7 m / sec-12 m / sec; the flow rate of fuel hydrogen during the second fuel hydrogen pressure stabilization and temperature control is 7 m / sec-12 m / sec; and the flow rate of cooling water during the first fuel hydrogen pressure stabilization and cooling is 0.5 m / sec. 3 / h-3.5m 3 / h; the flow rate of cooling water during the second fuel hydrogen pressure stabilization and cooling process is 0.5m. 3 / h-3.5m 3 / h; the temperature of the fuel hydrogen before the first pressure reduction is 30℃-45℃; the temperature of the cooling water during the first fuel hydrogen pressure stabilization and cooling is 35℃-45℃; the temperature of the cooling water during the second fuel hydrogen pressure stabilization and cooling is 15℃-30℃; the temperature of the cooling water before the second fuel hydrogen pressure stabilization and cooling is 5℃-10℃. By controlling the parameters of the above method, the temperature of the fuel hydrogen can be reduced by 2℃-15℃ during the first fuel hydrogen pressure stabilization and temperature control, and by 5℃-20℃ during the second fuel hydrogen pressure stabilization and cooling.

[0083] As a further refinement, the pressure of the fuel hydrogen during the first depressurization is 35-90 MPa; the pressure of the fuel hydrogen during the first pressure stabilization and temperature control is 25-55 MPa; the pressure of the fuel hydrogen during the second depressurization is 25-55 MPa; and the pressure of the fuel hydrogen during the second pressure stabilization and temperature reduction is 2-10 MPa. By controlling the parameters of the above methods, the stability of fuel hydrogen sampling in the sampling system can be achieved, and the pressure of the sampled hydrogen can be maintained between 2-10 MPa.

[0084] The features and beneficial effects of this invention are as follows:

[0085] (1) This invention can be used in different fuel hydrogen storage sites such as 35 MPa, 70 MPa, and 90 MPa, and meets the requirements of fuel hydrogen sampling safety and sampling stability.

[0086] (2) The present invention can effectively reduce pressure, cool down and stabilize the flow of high-pressure fuel hydrogen by addressing physical problems such as high pressure, temperature rise and vibration, thereby improving the safety performance of high-pressure fuel hydrogen sampling.

[0087] (3) During the continuous sampling of fuel hydrogen in the sampling system of the present invention, the pressure and temperature can be effectively controlled within the standard range, making the sampler more stable and the sampled gas more representative.

[0088] (4) The present invention relates to the corresponding outer casing and safety grounding, which can be directly applied to high-pressure fuel hydrogen sites, and can be rainproof, sunproof, and corrosion-resistant to a certain extent, thereby improving the service life of the system.

[0089] (5) During the high-pressure sampling process of the present invention, the sampling system can effectively reduce the temperature rise caused by high pressure. During the overall sampling process, the temperature can be effectively reduced by at least 7°C. The online sampling system of the present invention is applicable to fuel hydrogen with a temperature range of 25°C-50°C. After cooling the fuel hydrogen in the system, the temperature of the sample hydrogen at the sampling port is controlled at 20°C-36°C. Attached Figure Description

[0090] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0091] Figure 1 This is a schematic diagram of an online fuel hydrogen sampling system provided in an embodiment of the present invention.

[0092] Figure 2 This is a three-dimensional schematic diagram of an online fuel hydrogen sampling system provided in an embodiment of the present invention.

[0093] Figure 3 The variation of hydrogen pressure in the online sampling system provided in this embodiment of the invention.

[0094] Figure 4 The variation of hydrogen temperature in the online sampling system provided in this embodiment of the invention.

[0095] Figure 5 The change in hydrogen pressure during continuous sampling at the sampling port of the online sampling system provided in this embodiment of the invention.

[0096] The above figures include the following reference numerals:

[0097] 1- Filling port; 2- High-pressure needle valve; 3- Flow stabilizing pipe; 4- Pressure reducing valve No. 1; 5- Inlet pressure gauge No. 1; 6- Outlet pressure gauge No. 1; 7- Pressure reducing and flow stabilizing device No. 1; 8- Pressure reducing valve No. 2; 9- Inlet pressure gauge No. 2; 10- Outlet pressure gauge No. 2; 11- Thermometer No. 1; 12- Pressure reducing and flow stabilizing device No. 2; 13- Thermometer No. 2; 14- Pressure gauge; 15- Sampling needle valve; 16- Cylinder inlet needle valve; 17- Cylinder pressure gauge; 18- Sampling cylinder; 19- Steel cylinder Bottle outlet needle valve; 20-One-way valve; 21-Relief needle valve; 22-Safety valve No. 1; 23-Safety valve No. 2; 24-Vacuum needle valve; 25-Flame arrester; 26-Vacuum outlet; 27-Water inlet; 28-Control valve; 29-Water outlet; 30-Cooling pipe; 31-Water inlet pipe; 32-Water outlet pipe; 33-Exhaust pipe; 34-Ventilation pipe; 35-Sample injection zone; 36-Pressure reduction and cooling zone; 37-Safety zone; 38-Exhaust zone; 39-Sampling zone. Detailed Implementation

[0098] To facilitate understanding of the present invention, a more comprehensive description of the invention will be provided below, along with preferred embodiments. However, it should be understood that these embodiments are for more detailed description only and should not be construed as limiting the invention in any way, i.e., not limiting the scope of protection of the invention; relational terms such as "number one" and "number two" are merely used to distinguish one component from another with the same name, and do not necessarily require or imply any such actual relationship or order between these components.

[0099] We are provided Figures 1-2The structure of an online sampling system can be obtained from the above. The sampling system mainly includes an injection zone 35, a pressure reduction and cooling zone 36, an exhaust zone 38, a safety zone 37, and a sampling zone 39. In the hydrogen flow path, the injection zone 35, pressure reduction and cooling zone 36, and exhaust zone 38 are connected sequentially. The safety zone 37 and sampling zone 39 are connected in parallel with the pressure reduction and cooling zone 36. The pressure reduction and cooling zone 36 is equipped with a first pressure reducing valve 4, a first cooling and flow stabilizing device 7, a second pressure reducing valve 8, and a second cooling and flow stabilizing device 12. In the hydrogen flow path, the first pressure reducing valve 4, the first cooling and flow stabilizing device 7, the second pressure reducing valve 8, and the second cooling and flow stabilizing device 12 are connected in series. The first cooling and flow stabilizing device 7 is also connected to the second cooling and flow stabilizing device 12 via a cooling pipe 30. Through the coordinated operation of pressure reducing valve 4, cooling and flow stabilizing device 7, pressure reducing valve 8, and cooling and flow stabilizing device 12, a step-wise pressure drop of high-pressure fuel hydrogen is achieved, effectively reducing the temperature of the hydrogen in the gas pipe and controlling the large-scale temperature rise of the pressure reducing valves. Pressure reducing valve 4 and pressure reducing valve 8 enable a step-wise decrease in the pressure of the fuel hydrogen in the gas pipe. Their coordinated operation not only reduces pressure reducing valve vibration but also controls the significant temperature rise of the pressure reducing valves during the pressure drop process, thus improving the stability and safety of the entire sampling system. The cooperation between pressure reducing valve 4 and cooling and stabilizing device 7 ensures that the hydrogen gas in the gas pipe will not only increase in temperature and expand in volume after passing through pressure reducing valve 4, but also buffer the fuel hydrogen after the first stage of pressure reduction, thereby improving the stability of the system and controlling the temperature of the hydrogen gas in the gas pipe. The cooperation between pressure reducing valve 4 and cooling and stabilizing device 7 helps to improve the stability and safety of the sampling system, while promoting the second pressure reduction of hydrogen gas with more stable pressure and temperature, thus laying the foundation for the second stable pressure reduction process of hydrogen gas. With the cooperation of pressure reducing valve 8 and cooling and stabilizing device 12, the hydrogen gas after passing through cooling and stabilizing device 7 enters pressure reducing valve 8 for a second pressure reduction. Cooling and stabilizing device 12 can buffer the fuel hydrogen after passing through pressure reducing valve 8, improving system stability while cooling the temperature of the hydrogen in the gas pipe, which helps keep the final temperature of the fuel hydrogen within the standard range. With the cooperation of pressure reducing valve 8 and cooling and stabilizing device 12, it is beneficial to stably complete the step-by-step pressure reduction process of high-pressure fuel hydrogen and control and reduce the temperature of hydrogen in the gas pipe during the pressure reduction process, thereby improving the stability and safety of the entire system.With the cooperation of the No. 1 cooling and flow stabilizing device 7 and the No. 2 cooling and flow stabilizing device 12, the hydrogen pressure is stabilized in stages while the temperature of the hydrogen in the gas pipe is controlled and reduced. This not only ensures the stability of the hydrogen pressure drop process during the step-by-step decompression, but also ultimately reduces the temperature of the fuel hydrogen in the gas pipe, thereby improving the safety of the entire sampling process and ensuring the authenticity of the fuel hydrogen sample.

[0100] Regarding the parameter settings for the No. 1 cooling and flow stabilizing device 7 and the No. 2 flow stabilizing device 12: The No. 1 cooling and flow stabilizing device 7 includes a No. 1 fuel hydrogen cooling channel and a No. 1 fuel hydrogen pressure stabilizing channel, with the No. 1 fuel hydrogen cooling channel surrounding the No. 1 fuel hydrogen pressure stabilizing channel to form a No. 1 sealed cavity; the No. 2 cooling and flow stabilizing device 12 includes a No. 2 fuel hydrogen cooling channel and a No. 2 fuel hydrogen pressure stabilizing channel, with the No. 2 fuel hydrogen cooling channel surrounding the No. 2 fuel hydrogen pressure stabilizing channel to form a No. 2 sealed cavity; the No. 1 fuel hydrogen cooling channel of the No. 1 cooling and flow stabilizing device 7 is also connected to the No. 2 fuel hydrogen cooling channel of the No. 2 cooling and flow stabilizing device 12 via a cooling pipe 30. The No. 1 fuel hydrogen pressure stabilizing channel is a coiled No. 1 spiral pipe; the No. 2 fuel hydrogen pressure stabilizing channel is a coiled No. 2 spiral pipe. Both the first and second spiral conduits are 3 / 8 inch seamless pipes; the curvature of both spiral conduits is not less than the minimum bending radius; the wall thickness of both spiral conduits is not less than 3 mm; the diameter through which hydrogen flows through both spiral conduits is not less than 9.5 mm; the diameter of both spiral conduits is not less than 200 mm; the length of the first spiral conduit is h1, and the length of the second spiral conduit is h2.

[0101]

[0102]

[0103] Where: A1 and A2 are the heat transfer areas (m²) of spiral pipe No. 1 and spiral pipe No. 2, respectively. 2 ); d1 and d2 are the diameters (mm) of hydrogen flow through the first spiral pipe and the second spiral pipe, respectively; the length of the first sealed cavity is not less than 1.5 times the diameter of the first spiral pipe; the height of the first sealed cavity is not less than 1.5 times the diameter of the first spiral pipe; the volume of the first sealed cavity meets the pressure requirements for cooling water circulation; the length of the second sealed cavity is not less than 1.5 times the diameter of the second spiral pipe; the height of the second sealed cavity is not less than 1.5 times the diameter of the second spiral pipe; the volume of the second sealed cavity meets the pressure requirements for cooling water circulation; the height ratio of the second sealed cavity to the first sealed cavity with the same diameter is 2:3.

[0104] The pressure reduction and cooling zone 36 also includes an inlet 27, an outlet 29, an inlet pipe 31, and an outlet pipe 32. The inlet pipe 31 connects the inlet 27 to the second cooling and flow stabilizing device 12; the outlet pipe 32 connects the outlet 29 to the first cooling and flow stabilizing device 7; and a control valve 28 is installed on the inlet pipe 31. Through the above design, the cooling water after heat exchange in the second cooling and flow stabilizing device 12 flows into the first cooling and flow stabilizing device 7 to stabilize the temperature of the hydrogen in the first cooling and flow stabilizing device 7, thereby achieving full utilization of resources. In addition, by adjusting the control valve 28, the flow rate of the cooling water in the first cooling and flow stabilizing device 7 and the second cooling and flow stabilizing device 12 is controlled, thereby regulating the efficiency of heat exchange. Ultimately, it can be successfully achieved that the cooling water flowing from the first cooling and flow stabilizing device 7 into the second cooling and flow stabilizing device 12 can not only control the temperature of the hydrogen, but also further reduce the temperature of the hydrogen in the first cooling and flow stabilizing device 7. The pressure reduction and cooling zone 36 further includes a first temperature gauge 11, a second temperature gauge 13, a pressure gauge 14, and a sampling needle valve 15. The first temperature gauge 11 is positioned between the second pressure reducing valve 8 and the second cooling and flow stabilizing device 12. The second temperature gauge 13 is positioned between the second cooling and flow stabilizing device 12 and the pressure gauge 14. The pressure gauge 14 is positioned between the second temperature gauge 13 and the sampling needle valve 15. Along the hydrogen flow path, the second cooling and flow stabilizing device 12, the second temperature gauge 13, the pressure gauge 14, and the sampling needle valve 15 are sequentially arranged. The first temperature gauge 11 and the second temperature gauge 13 can directly reflect the hydrogen temperature after passing through the first cooling and flow stabilizing device 7 and the second cooling and flow stabilizing device 9. The first temperature gauge 11 and the second temperature gauge 13 can directly reflect whether the efficiency of heat exchange in the first cooling and flow stabilizing device 7 and the second cooling and flow stabilizing device 9 is reasonably controlled.

[0105] The safety zone 37 can improve the safety of the pressure reduction and cooling zone 36, thus benefiting the safety of the sampling system. On the other hand, the safety zone 37 can discharge residual hydrogen in the sampling system into the exhaust zone 38 through the connected pressure reduction and cooling zone 36, thus helping to improve the lifespan of the sampling system. Safety zone 37 includes a venting needle valve 21, a first safety valve 22, and a second safety valve 23. The venting needle valve 21 is located between the first cooling and flow stabilizing device 7 and the second pressure reducing valve 8. The first safety valve 23 is located between the second pressure reducing valve 8 and the second cooling and flow stabilizing device 12. The second safety valve 23 is located between the second cooling and flow stabilizing device 12 and the second thermometer 13. The venting needle valve 21, the first safety valve 22, and the second safety valve 13 are connected in parallel to the exhaust pipe 33 between the sampling needle valve 15 and the flame arrester 25. The exhaust pipe 33 includes a venting needle valve 24. In the hydrogen flow path, the venting needle valve 24 is located at the connection point between the venting needle valve 21, the first safety valve 22, and the second safety valve 23, which are connected in parallel, and the sampling needle valve 15. The above design allows for the discharge of hydrogen from the sampling system through the coordinated operation of the valves. When the pressure gauge 5 at the inlet of pressure relief valve 4 or the pressure gauge 6 at the outlet of pressure relief valve 4 malfunctions, the hydrogen in the pipeline can be quickly released by opening the venting needle valve 21. Safety valve 22 is used to discharge hydrogen between pressure relief valve 8 and cooling / stabilizing device 12. Safety valve 23 is used to discharge hydrogen between cooling / stabilizing device 12 and thermometer 13. This coordinated operation of the valves enhances the safety of the pressure relief and cooling zone 36.

[0106] The sample injection section includes the injection port 1, the high-pressure needle valve 2, and the flow stabilizer 3. In the hydrogen flow path, the injection port 1, high-pressure needle valve 2, and flow stabilizer 3 are connected in series, with flow stabilizer 3 connected to pressure reducing valve 4. The cooperation between flow stabilizer 3 and pressure reducing valve 4 helps stabilize the pressure of hydrogen flowing into the sampling system from the injection port, thus preparing for the stable decompression and cooling processes of the hydrogen, and improving the stability and safety of the entire system. We also designed the flow stabilizer 3 as a 3 / 8 inch seamless pipe; the wall thickness of flow stabilizer 3 is not less than 3 mm; the diameter of flow stabilizer 3 is not less than 9.5 mm; the bending radius of flow stabilizer 3 is not less than 200 mm; and the length of flow stabilizer 3 is not less than 1.5 m.

[0107] The exhaust section 38 includes a flame arrester 25 and an exhaust port 26; the flame arrester 25 and the exhaust port 26 are connected in series along the hydrogen flow path; an exhaust pipe 33 is provided between the flame arrester 25 and the sampling needle valve 15. The flame arrester 25 installed at the exhaust port 26 is used to prevent the flame of flammable gas and flammable liquid vapor from spreading to the safety device, which can further improve the safety of the sampling system.

[0108] Sampling section 39 includes a sampling cylinder group. The inlet of the sampling cylinder group is connected to the exhaust pipe 33 between the venting needle valve 24 and the sampling needle valve 15 on the exhaust pipe 33. The outlet of the sampling cylinder group is connected to the exhaust pipe 33 via a gas exchange pipe 34, which connects the flame arrester 25, the relief needle valve 21, the first safety valve 22, and the second safety valve 23 in parallel at the midpoint of the connection between the sampling needle valve 15 and the flame arrester 25 on the exhaust pipe 33. The gas exchange pipe 34 also includes a one-way valve 20. The sampling cylinder group includes a cylinder inlet needle valve 16, a cylinder pressure gauge 17, a sampling cylinder 18, and a cylinder outlet needle valve 19. In the hydrogen flow path, the cylinder inlet needle valve 16, the cylinder pressure gauge 17, the sampling cylinder 18, and the cylinder outlet needle valve 19 are connected in series.

[0109] Pressure reducing valve 4 includes an inlet pressure gauge 5 and an outlet pressure gauge 6; pressure reducing valve 8 includes an inlet pressure gauge 9 and an outlet pressure gauge 10. When the pressure at filling port 1 is 35 MPa, the first safety valve 22 is set to release pressure at a range of 35 MPa-44 MPa; when the pressure at filling port 1 is 75 MPa, the first safety valve 22 is set to release pressure at a range of 75 MPa-85 MPa; when the pressure at filling port 1 is 90 MPa, the first safety valve 22 is set to release pressure at a range of 90 MPa-100 MPa. The second safety valve 23 is set to release pressure at a range of 10 MPa. Both pressure reducing valves 4 and 8 can operate at pressures suitable for conditions ranging from 0 to 15000 psi g. The operating pressures of all hardware, valves, pipelines, and joints in the sampling system can also meet the requirements for conditions ranging from 0 to 15000 psi g, ensuring the safety and stability of the system. The valves, pipelines, and hardware in the sampling system undergo inert passivation treatment. This helps extend the service life of the sampling system. The invention also includes an outer casing and safety grounding, allowing direct application to high-pressure fuel hydrogen sites. It provides rain and sun protection, and to some extent, corrosion resistance, further improving the system's lifespan.

[0110] This invention also provides a sampling method for the online sampling system, wherein fuel hydrogen flows sequentially through the sampling system's injection zone, depressurization and cooling zone, and exhaust zone. During the depressurization and cooling zone, the fuel hydrogen undergoes a first depressurization, a first pressure stabilization and temperature control, a second depressurization, and a second pressure stabilization and cooling. The cooling water from the second cooling is used for the first temperature control. This method achieves step-by-step depressurization of high-pressure fuel hydrogen while simultaneously controlling and cooling the hydrogen during this process, ensuring the entire sampling system remains in a stable sampling state and yields fuel hydrogen samples with temperatures within the standard range. The combined effect of the first and second depressurizations facilitates step-by-step depressurization of the fuel hydrogen in the sampling system, reducing vibration during the depressurization process and controlling the significant temperature increase of the depressurization components due to pressure drop, thus contributing to the stability and safety of the sampling system. The combined action of the first fuel hydrogen depressurization and the first fuel hydrogen pressure stabilization and temperature control allows for control of the hydrogen pressure and temperature after the first depressurization. This improves the stability of the sampling system and ensures that the hydrogen gas maintains a stable pressure and temperature after the first depressurization, facilitating a stable second depressurization process. The combined action of the second fuel hydrogen depressurization and the second fuel hydrogen pressure stabilization and temperature reduction stabilizes the hydrogen gas after the second depressurization, successfully enhancing the stability and safety of the entire sampling system and achieving temperature reduction of the fuel hydrogen. The combined action of the first and second fuel hydrogen pressure stabilization and temperature control achieves a step-by-step pressure stabilization process while controlling and reducing the hydrogen temperature, thus improving the stability of the hydrogen gas during the step-by-step depressurization process and effectively controlling and reducing the temperature of the fuel hydrogen.

[0111] Fuel flowing into the depressurization and cooling zone can also flow into the safety zone and then into the exhaust zone. Fuel hydrogen flowing into the depressurization and cooling zone can flow into the safety zone through at least three branches. The first branch is used to drain the fuel hydrogen between the completion of the first fuel hydrogen pressure stabilization and temperature control and before the second fuel hydrogen depressurization. The second branch is used to drain the fuel hydrogen between the completion of the second fuel hydrogen depressurization and before the second fuel hydrogen pressure stabilization and cooling. The third branch is used to drain the fuel hydrogen after the completion of the second fuel hydrogen pressure stabilization and cooling. The three branches are connected to the same gas path that flows out of the safety zone. The fuel hydrogen flowing out of the safety zone flows into the pipeline connecting the depressurization and cooling zone and the exhaust zone, and then flows into the exhaust zone.

[0112] After the second stabilization and cooling of the fuel hydrogen, it can flow into the sampling zone after exiting the depressurization and cooling zone. Part of the fuel hydrogen flowing out of the depressurization and cooling zone flows into the sampling zone for sampling, while the other part flows into the exhaust zone through the pipeline from the safety zone to the exhaust zone. The residual fuel hydrogen flowing out of the sampling zone can be combined with the fuel hydrogen in the pipeline connecting the safety zone to the depressurization and cooling zone and the exhaust zone and then flow into the exhaust zone together.

[0113] To clarify the specific operation of this invention, the following operation method is provided: Sampling reference standard T / CECA-G0186-2022 "Hydrogen Sampling Specification for Proton Exchange Membrane Fuel Cells", the specific operation is as follows:

[0114] Before sampling, check the online sampling system to confirm its connection status with the main pipeline and the connection status of the sampling system's filling port 1, venting port 26, and the on-site recovery pipeline. Also confirm that all valves in the online sampling system are closed. Confirm that the safety grounding clamp is connected to the static electricity point. Verify that all pressure gauges in the online sampling system are at zero, that the temperature gauges are functioning normally, and that the external inlet control valve 28 of the inlet pipe 31 is closed. If any pressure gauge in the sampling system displays a non-zero reading, release pressure through the venting needle valve 21, safety valve 22 (number one), and safety valve 23 (number two) until the pressure gauges in the sampling system return to zero. If the pressure gauges cannot return to zero, check for blockages in the pipelines of the sampling zone 35, pressure reduction and cooling zone 36, sampling zone 39, safety zone 37, and venting zone 38 in sequence. After confirmation, the cylinder is connected to the sampling zone 39 and the exhaust zone 38 via the cylinder inlet needle valve 16 and the cylinder outlet needle valve 19, and then the cylinder inlet needle valve 16 and the cylinder outlet needle valve 19 are closed. In addition, the external inlet control valve 28 of the water inlet pipe 31 needs to be opened in advance to circulate cooling water for the first cooling and flow stabilizing device 7 and the second cooling and flow stabilizing device 12.

[0115] (1) Open the high pressure needle valve 2 and the fuel hydrogen field main pipeline valve to introduce fuel hydrogen into the system and open the sampling needle valve 15 and the venting needle valve 24.

[0116] (2) After the fuel hydrogen enters the system, adjust the first pressure reducing valve 4 to set a small gradient pressure reducing value; then adjust the second pressure reducing valve 8 to the required sampling pressure value.

[0117] (3) After the pressure is set, open the cylinder inlet needle valve 16 and the cylinder outlet needle valve 19, and close the venting needle valve 24. Operate the cylinder inlet needle valve 16. When the cylinder pressure gauge 17 is 0, reopen the cylinder inlet needle valve 16 to replace the system. The replacement should be done at least 3 times.

[0118] (4) After the replacement is completed, close the cylinder outlet needle valve 19 and take system samples. The specific sampling pressure is determined by the cylinder pressure gauge 17. If there are records of fuel hydrogen temperature and sampling port pressure, the values ​​of the system temperature gauge 13 and the sampling pressure gauge 14 can be recorded.

[0119] (5) After sampling is completed, close the main pipeline valve and the system high-pressure needle valve 2, open the venting needle valve 21, and close the sampling needle valve 15 and the cylinder inlet needle valve 16. Adjust the No. 1 pressure reducing valve 4 to the fully open state of 0 MPa to empty the system high-pressure stage pressure. The specific emptying pressure is detected by the pressure at both ends of the pressure reducing valve. After the high-pressure pipeline is emptied, open the venting needle valve 24 to vent the pipeline behind the system No. 2 pressure reducing valve 8.

[0120] (6) After the system is emptied, remove the sampling cylinder 18, disconnect the electrostatic connection, restore the system, and close the system cabinet door. Sampling is now complete.

[0121] Validation Result Analysis

[0122] To illustrate the specific technical points of the embodiments of the present invention, the main technical specifications of the main components of the online fuel hydrogen sampling system of the embodiments are shown in Table 1 below:

[0123] (1) It can be used for on-site online sampling of 35Mpa, 70Mpa and 90Mpa high-pressure fuel hydrogen in places such as hydrogen storage stations, fuel hydrogen receiving stations and hydrogen production and storage stations;

[0124] (2) The overall system sampling pipeline fittings are designed with a minimum pressure resistance of 20,000 psi g and a maximum design pressure of 15,000 psi g, or 110 MPa.

[0125] (3) The system has cooling, pressure reduction and flow stabilization processes, which can maintain the temperature of fuel hydrogen within 55°C during the sampling process and perform stable pressure sampling.

[0126] Table 1. Technical Specifications of Main Components of the Online Sampling System

[0127] 1 High-pressure needle valve 20000psig 0-15000psig 316L / 2 No. 1 pressure reducing valve 20000psig 0-15000psig 316L / 3 No. 2 pressure reducing valve 20000psig 0-15000psig 316L / 4 Safety Valve No. 1 20000psig 35 / 75 / 90Mpa 316L Optional use 5 Safety valve No. 2 15000psig 15Mpa 316L Factory settings 6 vent needle valve 20000psig 0-15000psig 316L / 7 Evacuation needle valve 20000psig 0-15000psig 316L / 8 No. 1 Cooling and Stabilizing Device 15000psig / 316L Medium Piping Parameters 9 No. 2 Cooling and Flow Stabilizing Device 15000psig / 316L Medium Piping Parameters 10 Sampling needle valve 20000psig 0-15000psig 316L / 11 one-way valve 15000psig 0.01Mpa 316L Startup pressure 12 Sampling cylinder 30Mpa 0-20Mpa 316L / 13 Pressure reducing valve pressure gauge 20000psig 0-14000psig 316L Pressure display range 14 No. 2 outlet pressure gauge 15000psig 0-3000psig 316L Operating parameters 15 Outer box / / 316L Anti-corrosion coating

[0128] Table 2 Online sampling results for different embodiments

[0129]

[0130] We from Figure 3As can be seen, the online sampling system of this invention can continuously sample fuel hydrogen at pressures ranging from 35 MPa to 90 MPa. The fuel hydrogen undergoes a stepped pressure drop process within the system, and even at 90 MPa, the stepped pressure drop is very gradual. This demonstrates that the coordinated operation of the first pressure-reducing valve, the first cooling and flow-stabilizing device, the second pressure-reducing valve, and the second cooling and flow-stabilizing device in the sampling system of this invention enables continuous and stable sampling, and the hydrogen pressure at the sampling port does not exceed 10 MPa, which is beneficial for improving the safety of the sampling system. The stepped pressure drop of pressure reducing valves No. 1 and No. 2 improves the stability of the sampling system and can also alleviate the rapid temperature rise of the pressure reducing components caused by the pressure drop during the pressure reduction process. This effectively controls the temperature rise of fuel hydrogen and related hardware facilities such as pressure reducing valves No. 1 and No. 2 caused by the pressure drop, which is beneficial to improving the safety of the sampling system. Meanwhile, cooling and stabilizing devices No. 1 and No. 2 can stabilize the hydrogen after the stepped pressure reduction of pressure reducing valves No. 1 and No. 2, which further improves the stability of the sampling system and also helps to promote the stability of the pressure reduction process.

[0131] We from Figure 4 As can be seen, the temperature change of hydrogen in the gas tube of the sampling system of this invention is observed. The cooperation of the first and second cooling and stabilizing devices significantly reduces the temperature rise of hydrogen caused by the pressure drop process. The temperature at the sampling port of the sampling system is effectively controlled at 36°C, ensuring the authenticity of the sample. Furthermore, the first and second cooling and stabilizing devices also improve the temperature stability of the hydrogen after cooling. Firstly, the first cooling and stabilizing device is connected after the first pressure reducing valve, which reduces the temperature rise of hydrogen caused by the first pressure reducing valve. Similarly, the second cooling and stabilizing device is connected after the second pressure reducing valve, which reduces the temperature rise of hydrogen caused by the second pressure reducing valve. Therefore, the cooperation of the first and second cooling and stabilizing devices, along with the coordination between the first and second pressure reducing valves, facilitates the step-by-step cooling process of fuel hydrogen during the step-by-step pressure reduction process, thereby improving the safety and stability of the sampling system.

[0132] As shown in Table 2, in Examples 1-5, when the online sampling system samples hydrogen gas at pressures between 35 MPa and 90 MPa, we can control the pressure drop during the first and second pressure reduction processes, the flow rate of cooling water in the first and second cooling and stabilizing devices, the flow rate of hydrogen gas in these devices, the temperature of the cooling water in these devices, the temperature of the cooling water flowing into the first cooling and stabilizing device, and the temperature of the hydrogen gas at the first inlet pressure gauge. By controlling these parameters in the online sampling system, we can ensure a stable and continuous sampling process, and the temperature of the sample hydrogen gas taken out at the system outlet can be between 20°C and 36°C, with a pressure between 2 MPa and 10 MPa. Furthermore, we can... Figure 5 The verification results show that the sampling pressure at the sampling port of the sampling system remains stable, indicating that the stability of the online sampling system of the present invention is improved.

[0133] It should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A sampling method for a high-pressure fuel hydrogen online sampling system, characterized in that, Fuel hydrogen is injected through a gas tube, and then the fuel hydrogen is subjected to step-by-step depressurization while the pressure and temperature of the fuel hydrogen after step-by-step depressurization are stabilized. Then, a portion of the fuel hydrogen is sampled, and the other portion of the fuel hydrogen is discharged through a pipeline connected to the exhaust. The step-by-step pressure reduction of fuel hydrogen includes the first fuel hydrogen pressure reduction, the first fuel hydrogen pressure stabilization and temperature control, the second fuel hydrogen pressure reduction, and the second fuel hydrogen pressure stabilization and temperature reduction. The cooling water from the second cooling of the fuel hydrogen is used for the first temperature control of the fuel hydrogen. The sampling temperature of the fuel hydrogen in the sampling system is 20℃-36℃; the pressure of the fuel hydrogen during the injection of the sampling system is 35MPa-90MPa; the pressure of the fuel hydrogen during the sampling system is 2MPa-10MPa. The temperature range during the first fuel hydrogen pressure stabilization and temperature control is 2℃-15℃; the temperature range during the second fuel hydrogen pressure stabilization and temperature reduction is 5℃-20℃. The flow rate of fuel hydrogen during the first fuel hydrogen pressure stabilization and temperature control is 7 m / sec-12 m / sec; the flow rate of fuel hydrogen during the second fuel hydrogen pressure stabilization and temperature control is 7 m / sec-12 m / sec; and the flow rate of cooling water during the first fuel hydrogen pressure stabilization and cooling is 0.5 m / sec. 3 / h-3.5m 3 / h; the flow rate of cooling water during the second fuel hydrogen pressure stabilization and cooling process is 0.5m. 3 / h-3.5m 3 / h; the temperature of the fuel hydrogen before the first pressure reduction is 30℃-45℃; the temperature of the cooling water during the first fuel hydrogen pressure stabilization and cooling is 35℃-45℃; the temperature of the cooling water during the second fuel hydrogen pressure stabilization and cooling is 15℃-30℃; the temperature of the cooling water before the second fuel hydrogen pressure stabilization and cooling is 5℃-10℃; The pressure of the fuel hydrogen during the first depressurization is 35 MPa-90 MPa; the pressure of the fuel hydrogen during the first stabilization and temperature control is 25 MPa-55 MPa; the pressure of the fuel hydrogen during the second depressurization is 25 MPa-55 MPa; the pressure of the fuel hydrogen during the second stabilization and temperature control is 2 MPa-10 MPa. By controlling the parameters of the above methods, the stability of the fuel hydrogen sampling in the sampling system is achieved, and the pressure of the sampled hydrogen is between 2 MPa and 10 MPa. The fuel hydrogen undergoing step-wise pressure reduction flows into the safety zone and is then discharged. This step-wise pressure reduction occurs through at least three branches: the first branch discharges the fuel hydrogen between the completion of the first fuel hydrogen pressure stabilization and temperature control and before the second fuel hydrogen pressure reduction; the second branch discharges the fuel hydrogen between the completion of the second fuel hydrogen pressure reduction and before the second fuel hydrogen pressure stabilization and temperature reduction; and the third branch discharges the fuel hydrogen after the completion of the second fuel hydrogen pressure stabilization and temperature reduction. These three branches are then connected to the same gas path exiting the safety zone. The fuel hydrogen exiting the safety zone flows into the pipeline connected to the exhaust gas after the second fuel hydrogen pressure stabilization and temperature reduction, and is then discharged.

2. The sampling method of the high-pressure fuel hydrogen online sampling system according to claim 1, characterized in that, The residual fuel hydrogen was discharged after sampling.

3. The sampling method of the high-pressure fuel hydrogen online sampling system according to claim 1, characterized in that, After the second fuel hydrogen pressure stabilization and cooling process is completed, a portion of the fuel hydrogen is sampled, while the other portion, along with the safe zone fuel hydrogen, flows into the pipeline connected to the exhaust after the second fuel hydrogen pressure stabilization and cooling process is completed. The fuel hydrogen is then discharged together.

4. The sampling method of the high-pressure fuel hydrogen online sampling system according to claim 1, characterized in that, The residual fuel hydrogen after sampling is combined with the fuel hydrogen flowing from the safe zone into the pipeline connected to the exhaust after the second fuel hydrogen stabilization and cooling process, and then discharged together.

Images