Emptying device for liquid-phase hydrogen

Abstract

The emptying device comprises an emptying pipe, and the input end of the emptying pipe is communicated with a liquid-phase hydrogen source; the partial pressure vaporization emptying mechanism comprises a plurality of partial pressure pipes, the input ends of the partial pressure pipes are communicated with the output end of the emptying pipe, the partial pressure pipes are provided with heating devices, and the output ends of the partial pressure pipes are provided with primary emptying torches; and the throttling depressurization emptying mechanism comprises a plurality of throttling pipes, the input ends of the throttling pipes are communicated with any one of the partial pressure pipes, the throttling pipes are provided with throttling valves, and the output ends of the throttling pipes are provided with second-stage emptying torches. The technical problems that when liquid-phase hydrogen is emptied, personnel frostbite, explosion overpressure and fire and rain hazards are likely to be caused can be solved, and safe emptying of the liquid-phase hydrogen is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of liquid phase hydrogen venting, and in particular to a venting device for liquid phase hydrogen. Background Art

[0002] Hydrogen is widely present in natural environments such as the earth's crust, oceans and atmosphere. Its critical temperature is about -239.96°C and its critical pressure is about 1.3MPa. It is separated through a preparation process and is mainly used as a raw material for combustion and energy supply in industry. In addition, it can also be used in the production of on-board hydrogen batteries.

[0003] When transporting liquid hydrogen through a pipeline, safety accidents such as leakage may occur due to factors such as damage to the pipeline itself and by a third party. Once a safety accident occurs, the liquid inside the accident pipe section needs to be drained at the valve chamber before pipeline maintenance can be carried out. At this time, the pipeline liquid is usually vented.

[0004] Since the critical temperature of liquid hydrogen is much lower than normal temperature, compared with liquefied natural gas, liquid ethane and other transport media, the liquid hydrogen transport temperature needs to be lower than its critical temperature of -239.96°C, which belongs to the category of ultra-low temperature transport. During the venting process, liquid hydrogen will undergo a more drastic gas-liquid phase change. At this time, gaseous hydrogen, gas-liquid two-phase hydrogen, saturated hydrogen and supercooled hydrogen may exist, which greatly increases the complexity of the flow of liquid hydrogen in the pipeline, and also has very high requirements for the safe venting device when a leak occurs in the transport pipeline.

[0005] There are currently two types of venting methods: cold venting and hot venting. Cold venting refers to the direct discharge of vented materials into the environment without treatment, and hot venting refers to the use of a torch to ignite the vented materials before discharge. Since the temperature of liquid hydrogen transportation is much lower than the ambient temperature, when an accident occurs in the pipeline or maintenance and inspection conditions are in place, if the cold venting process of a conventional liquid pipeline is used, the liquid hydrogen in the pipe will boil violently and evaporate into a gas phase. In this process, liquid hydrogen absorbs a large amount of heat from the environment, causing the temperature of the surrounding environment and pipelines to drop sharply, posing a frostbite hazard to nearby workers; in addition, the flammable limit range of hydrogen in the air is 4-75%, and the detonation limit range is 18.3-59%. This concentration range is much larger than that of combustible media such as natural gas. Liquid hydrogen is prone to generate and accumulate static electricity when it flows. Compared with liquid media such as liquid ethane, direct venting is more likely to cause explosion overpressure and other hazards.

[0006] In summary, the following problems exist when venting liquid hydrogen: (1) frostbite caused by phase change; (2) explosion overpressure caused by the flammable limit and detonation limit of hydrogen and static electricity; (3) possible fire rain hazards during venting; and (4) the problem of exhausting residual hydrogen after venting. All of the above problems may cause serious hazards and need to be effectively dealt with. Summary of the invention

[0007] The purpose of the present invention is to provide a venting device for liquid hydrogen to solve the technical problems of frostbite, explosion overpressure and fire rain hazards that are easily caused when liquid hydrogen is vented, so as to achieve safe venting of liquid hydrogen.

[0008] The present invention is achieved through the following technical solutions:

[0009] A venting device for liquid hydrogen comprises: a venting pipe, the input end of which is connected to a liquid hydrogen source; a pressure-dividing vaporizing venting mechanism, the pressure-dividing vaporizing venting mechanism comprises a plurality of pressure-dividing pipes, the input end of which is connected to an output end of the venting pipe, the pressure-dividing pipe is provided with a heating device, and the output end of the pressure-dividing pipe is provided with a primary venting torch; a throttling and pressure-reducing venting mechanism, the throttling and pressure-reducing venting mechanism comprises a plurality of throttling pipes, the input end of which is connected to any one of the pressure-dividing pipes, the throttling pipe is provided with a throttling valve, and the output end of the throttling pipe is provided with a secondary venting torch.

[0010] Optionally, a pressure relief pipe is connected to the output end of the throttling pipe, and the output ends of all the pressure relief pipes are commonly connected to a surplus gas pipe, and the output end of the surplus gas pipe is provided with a three-stage venting torch.

[0011] Optionally, the pressure dividing tube corresponds to the throttling tube one by one and is connected.

[0012] Optionally, the input ends of the first-stage venting flare, the second-stage venting flare and the third-stage venting flare are all provided with flame arresters.

[0013] Optionally, the vent pipe, the pressure dividing pipe, the pressure relief pipe and the residual gas pipe are all provided with flow meters.

[0014] Optionally, the vent pipe, the pressure dividing pipe, the throttling pipe, the pressure relief pipe and the residual gas pipe are all provided with a plurality of pressure gauges.

[0015] Optionally, the vent pipe, the pressure dividing pipe, the pressure relief pipe and the residual gas pipe are all provided with a plurality of temperature gauges.

[0016] Optionally, the vent pipe, the pressure dividing pipe, the throttling pipe, the pressure relief pipe and the residual gas pipe are all provided with a plurality of control valves.

[0017] Optionally, a recoil pipe is connected to the vent pipe, and the recoil pipe is connected to a nitrogen purge device.

[0018] Optionally, the recoil pipe is provided with the temperature increasing device, the pressure gauge, the temperature gauge and the control valve.

[0019] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0020] The present invention provides a venting device for liquid hydrogen. By setting a venting pipe, the venting pipe is used to connect with the leaking liquid hydrogen pipeline to guide the liquid hydrogen. On this basis, by setting a pressure-dividing vaporization venting mechanism, the venting mechanism includes a plurality of pressure-dividing pipes. First, the liquid hydrogen guided out of the venting pipe is diverted and the flow rate is evenly distributed. Then, the diverted liquid hydrogen is heated by a heating device arranged in the pressure-dividing pipe to make it initially vaporized in the pressure-dividing pipe, thereby solving the hazards of low temperature injuries and fire rain. On this basis, by setting a first-level venting torch, the initial The vaporized hydrogen is ignited for preliminary emptying; on this basis, a throttling and pressure-reducing emptying mechanism is set up, which includes multiple throttling tubes to divert the initially vaporized hydrogen, reduce the probability of explosion at the first-stage emptying torch, and throttle and reduce the pressure of the hydrogen that expands in volume after initial vaporization through the throttling valve to adjust the pressure of the hydrogen after phase change, and further prevent accidents such as flames and deflagration caused by excessive pressure during the emptying process; on this basis, a second-stage emptying torch is set up to ignite the hydrogen after heating and pressure reduction for effective emptying. Through the mutual cooperation of the above mechanisms, the emptying device for liquid hydrogen can solve the technical problems of frostbite, explosion overpressure and fire rain hazards that are easy to cause when liquid hydrogen is emptied, and realize the safe emptying of liquid hydrogen. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0022] Figure 1 A schematic diagram of a venting device for liquid hydrogen provided in an embodiment of the present invention;

[0023] Figure 2 A schematic diagram of the input end of a vent pipe of a venting device for liquid hydrogen provided in an embodiment of the present invention;

[0024] Figure 3 A schematic diagram of a recoil pipe of a venting device for liquid hydrogen provided in an embodiment of the present invention;

[0025] Figure 4 A schematic diagram of a partial pressure vaporization venting mechanism of a venting device for liquid hydrogen provided in an embodiment of the present invention;

[0026] Figure 5 A schematic diagram of a throttling, pressure-reducing and venting mechanism for a venting device for liquid hydrogen provided in an embodiment of the present invention;

[0027] Figure 6 A schematic diagram of the residual gas pipe of a venting device for liquid hydrogen provided in an embodiment of the present invention.

[0028] Marks and corresponding parts names in the attached drawings:

[0029] 10- vent pipe; 20- pressure dividing pipe; 21- heating device; 22- first-stage venting torch; 30- throttling pipe; 31- throttling valve; 32- second-stage venting torch; 40- pressure relief pipe; 41- residual gas pipe; 42- third-stage venting torch; 50- flame arrester; 60- flow meter; 61- pressure gauge; 62- temperature gauge; 63- control valve; 70- recoil pipe; 71- nitrogen purge device. DETAILED DESCRIPTION

[0030] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0031] Please refer to Figures 1 to 6 The embodiment of the present invention provides a venting device for liquid hydrogen, comprising: a venting pipe 10, the input end of which is connected to a liquid hydrogen source; a second pressure-dividing vaporization venting mechanism, the pressure-dividing vaporization venting mechanism comprising a plurality of pressure-dividing pipes 20, the input end of which is connected to the output end of the venting pipe 10, the pressure-dividing pipe 20 is provided with a heating device 21, and the output end of the pressure-dividing pipe 20 is provided with a primary venting torch 22; a third throttling and pressure-reducing venting mechanism, the throttling and pressure-reducing venting mechanism comprising a plurality of throttling pipes 30, the input end of the throttling pipe 30 is connected to any one of the pressure-dividing pipes 20, the throttling pipe 30 is provided with a throttling valve 31, and the output end of the throttling pipe 30 is provided with a secondary venting torch 32.

[0032] The present invention provides a venting device for liquid hydrogen. By setting a venting pipe 10, the venting pipe is connected with the leaking liquid hydrogen pipeline to guide the liquid hydrogen. On this basis, by setting a partial pressure vaporization venting mechanism, the venting mechanism includes a plurality of pressure dividing pipes 20. First, the liquid hydrogen guided out of the venting pipe 10 is diverted to evenly distribute the flow. Then, the diverted liquid hydrogen is heated by a heating device 21 arranged on the pressure dividing pipe 20 to make it initially vaporized in the pressure dividing pipe 20, thereby solving the hazards of low temperature injuries and fire rain. On this basis, by setting a first-level venting torch 22 , ignite the initially vaporized hydrogen and perform initial emptying; on this basis, by setting a throttling and pressure-reducing emptying mechanism, it is set to include multiple throttling tubes 30, divert the initially vaporized hydrogen, reduce the probability of explosion at the first-level emptying torch 22, and throttle and reduce the pressure of the hydrogen that expands after initial vaporization through the throttling valve 31, so as to adjust the pressure of the hydrogen after phase change, and further prevent accidents such as flames and deflagration caused by excessive pressure during the emptying process; on this basis, by setting a second-level emptying torch 32, ignite the hydrogen after heating and pressure reduction, and perform effective emptying. Through the mutual cooperation of the above-mentioned mechanisms, the emptying device for liquid hydrogen can solve the technical problems of frostbite, explosion overpressure and fire rain hazards that are easy to cause when liquid hydrogen is emptied, and realize the safe emptying of liquid hydrogen.

[0033] It should be noted that the input end of the throttling tube 30 is connected to the vicinity of the output end of the pressure dividing tube 20 to avoid premature drainage.

[0034] It should be noted that the above-mentioned temperature increasing device 21 can adopt any heating device in the prior art, such as an electric heating rod, an electric heating copper tube, an electric heating jacket, etc.

[0035] In order to process the very small amount of hydrogen remaining after the pressure divider tube 20 and the throttling tube 30 are processed, a pressure relief pipe 40 is connected to the output end of the throttling tube 30, and the output ends of all the pressure relief pipes 40 are commonly connected to a residual gas pipe 41, and the output end of the residual gas pipe 41 is provided with a three-stage venting torch 42.

[0036] The pressure relief pipe 40 conducts the residual hydrogen, and then the three-stage venting torch 42 is used to ignite the generated water to implement complete venting.

[0037] Preferably, in order to improve the simplicity of the overall structure while ensuring the processing capacity, the pressure dividing tube 20 corresponds to and is connected to the throttling tube 30 one by one.

[0038] It should be noted that other embodiments may also adopt a one-to-many setting for further processing, depending on the air pressure in the pressure dividing tube 20. The higher the air pressure, the more throttling tubes 30 can be connected to achieve better diversion and pressure reduction.

[0039] In order to prevent flashback accidents from occurring in the primary flare 22 , the secondary flare 32 , and the tertiary flare 42 , which may lead to explosions in the pipeline, flame arresters 50 are provided at the input ends of the primary flare 22 , the secondary flare 32 , and the tertiary flare 42 .

[0040] By providing the flame arrester 50, specifically, providing it at the tail end of the first-stage flare 22, the second-stage flare 32 and the third-stage flare 42, and providing it on the corresponding pipeline, a flashback accident is avoided, which may lead to an explosion in the pipeline.

[0041] It should be noted that the flame arrester 50 may be any torch flame arrester in the prior art as long as it can prevent flashback accidents.

[0042] Preferably, in order to measure the hydrogen flow in each pipeline in real time, the vent pipe 10 , the pressure dividing pipe 20 , the pressure relief pipe 40 and the residual gas pipe 41 are all provided with a flow meter 60 .

[0043] Specifically, the installation position is determined according to actual needs. Generally speaking, a flow meter 60 is respectively installed at the input end and the output end of each section of the pipeline. Preferably, on this basis, a flow meter 60 is also installed in the middle of the pipeline.

[0044] Preferably, in order to measure the hydrogen pressure in each pipeline in real time, the vent pipe 10 , the pressure dividing pipe 20 , the throttling pipe 30 , the pressure relief pipe 40 and the residual gas pipe 41 are all provided with a plurality of pressure gauges 61 .

[0045] Specifically, the installation position is determined according to actual needs. Generally speaking, a pressure gauge 61 is respectively installed at the input end and the output end of each section of the pipeline. Preferably, on this basis, a pressure gauge 61 is also installed in the middle of the pipeline.

[0046] Preferably, in order to measure the temperature in each pipeline in real time, the vent pipe 10 , the pressure dividing pipe 20 , the pressure relief pipe 40 and the residual gas pipe 41 are all provided with a plurality of temperature gauges 62 .

[0047] Specifically, the setting position is determined according to actual needs. Generally speaking, a temperature meter 62 is respectively set at the input end and the output end of each section of the pipeline. Preferably, on this basis, a temperature meter 62 is also set in the middle of the pipeline.

[0048] It should be noted that, in order to independently control the opening and closing of each pipeline, the vent pipe 10 , the pressure dividing pipe 20 , the throttling pipe 30 , the pressure relief pipe 40 and the residual gas pipe 41 are all provided with a plurality of control valves 63 .

[0049] In order to process the residual hydrogen in the pipeline after venting and prevent the remaining hydrogen in the pipeline from reaching the explosion limit, and at the same time ensure that the inside of the pipeline is isolated from the air to prevent pipeline corrosion, the venting pipe 10 is connected to a recoil pipe 70, and the recoil pipe 70 is connected to a nitrogen purge device 71.

[0050] By setting up a nitrogen purge device 71 and cooperating with the above-mentioned control valves 63, nitrogen is filled into the pipeline after being emptied, and the residual hydrogen in the pipeline is flushed with nitrogen to prevent the remaining hydrogen in the pipeline from reaching the explosion limit. At the same time, it ensures that the interior of the pipeline is filled with nitrogen and isolated from the air to prevent pipeline corrosion.

[0051] It should be noted that the above-mentioned nitrogen purge device 71 can adopt any relevant mechanism in the prior art, which generally has a discharge mechanism and a nitrogen storage mechanism, such as using a pump body to discharge liquid nitrogen, such as using a fan to discharge nitrogen, etc. Preferably, a pump body is used to discharge liquid nitrogen to improve nitrogen discharge efficiency and transfer efficiency.

[0052] Preferably, the recoil pipe 70 is provided with the temperature increasing device 21 , the pressure gauge 61 , the temperature gauge 62 and the control valve 63 .

[0053] Through the above arrangement, the temperature increasing device 21 is used to increase the temperature of the liquid nitrogen so that it vaporizes in the pipeline, instantly increasing the gas pressure in the pipeline, thereby facilitating the purging operation.

[0054] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A venting device for liquid hydrogen, characterized in that: include: A vent pipe (10), wherein an input end of the vent pipe (10) is connected to a liquid hydrogen source; A partial pressure vaporization venting mechanism, the partial pressure vaporization venting mechanism comprising a plurality of partial pressure pipes (20), the input end of the partial pressure pipe (20) being connected to the output end of the venting pipe (10), the partial pressure pipe (20) being provided with a temperature increasing device (21), and the output end of the partial pressure pipe (20) being provided with a primary venting torch (22); A throttling, pressure-reducing and venting mechanism, the throttling, pressure-reducing and venting mechanism comprises a plurality of throttling tubes (30), the input end of the throttling tube (30) is connected to any one of the pressure-dividing tubes (20), the throttling tube (30) is provided with a throttling valve (31), and the output end of the throttling tube (30) is provided with a secondary venting torch (32).

2. The venting device for liquid hydrogen according to claim 1, characterized in that: The output end of the throttling tube (30) is connected to a pressure relief tube (40), and the output ends of all the pressure relief tubes (40) are connected to a surplus gas tube (41) in common. The output end of the surplus gas tube (41) is provided with a three-stage venting torch (42).

3. The venting device for liquid hydrogen according to claim 1 or 2, characterized in that: The pressure dividing tube (20) corresponds to the throttling tube (30) one by one and is in communication with each other.

4. The venting device for liquid hydrogen according to claim 3, characterized in that: The input ends of the first-stage venting flare (22), the second-stage venting flare (32) and the third-stage venting flare (42) are all provided with flame arresters (50).

5. The venting device for liquid hydrogen according to claim 3, characterized in that: The vent pipe (10), the pressure dividing pipe (20), the pressure relief pipe (40) and the residual gas pipe (41) are all provided with a flow meter (60).

6. The venting device for liquid hydrogen according to claim 3, characterized in that: The vent pipe (10), the pressure dividing pipe (20), the throttling pipe (30), the pressure relief pipe (40) and the residual gas pipe (41) are all provided with a plurality of pressure gauges (61).

7. The venting device for liquid hydrogen according to claim 3, characterized in that: The vent pipe (10), the pressure dividing pipe (20), the pressure relief pipe (40) and the residual gas pipe (41) are all provided with a plurality of temperature gauges (62).

8. The venting device for liquid hydrogen according to claim 3, characterized in that: The vent pipe (10), the pressure dividing pipe (20), the throttling pipe (30), the pressure relief pipe (40) and the residual gas pipe (41) are all provided with a plurality of control valves (63).

9. The venting device for liquid hydrogen according to claim 3, characterized in that: The vent pipe (10) is connected to a recoil pipe (70), and the recoil pipe (70) is connected to a nitrogen purge device (71).

10. The venting device for liquid hydrogen according to claim 9, characterized in that: The recoil pipe (70) is provided with the temperature increasing device (21), the pressure gauge (61), the temperature gauge (62) and the control valve (63).

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