Spontaneous combustion prevention and control system and method for emptying system of hydrogen station yard

Abstract

The invention discloses a spontaneous combustion prevention and control system and method for a hydrogen station emptying system. The system comprises an emptying pipeline isolation system; the emptying main pipeline is used for connecting one end of the hydrogen station yard and is connected with a gas source branch so as to be connected with a gas source device, and an injection block valve is arranged on the emptying main pipeline; a replacement branch is arranged at the end, used for being connected with the emptying vertical pipe, of the emptying main pipe, and a replacement outlet block valve is arranged on the replacement branch. Gas in the replacement emptying main pipeline is controlled by opening or closing the injection block valve and the replacement outlet block valve; the emptying main pipeline at the downstream of the replacement branch comprises at least two emptying branches which are connected in parallel, one emptying branch is provided with a bypass block valve, and the other emptying branches are provided with rupture disks; the bypass block valve is used for being opened in the planned emptying state and the normal operation state of the hydrogen station, and the rupture disk is used for being broken in the non-planned emptying state. The system can solve the problem of spontaneous combustion in the unplanned emptying process of the hydrogen station.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen spontaneous combustion prevention and control, and in particular to a spontaneous combustion prevention and control system and method for a hydrogen station venting system. Background Art

[0002] Hydrogen energy is recognized as a clean and efficient energy source. Affected by the geographical differences in hydrogen production and utilization, medium and long-distance hydrogen transportation has gradually become a key link in the efficient utilization of hydrogen energy. Among them, pipeline transportation is a popular choice and development direction for hydrogen energy transportation. At present, the more suitable medium and long-distance hydrogen pipeline transportation modes include pure hydrogen pipeline transportation, high hydrogen-natural gas blended pipeline transportation, and low hydrogen-natural gas transportation. The specific selection can be based on the transportation distance and the adaptable hydrogen energy, natural gas resources and user market, and the above transportation modes can provide sufficient development support for hydrogen energy utilization.

[0003] In the pipeline transportation system, there are several typical stations, such as the first station, intermediate distribution station, booster station, and terminal station. These stations have their own metering, cleaning, booster, distribution, and pressure regulation functions. Although these stations have their own characteristics, they generally have planned and unplanned venting conditions. Planned venting is mainly to vent the station and its connected pipelines before maintenance, to empty the flammable media in the closed pipelines and equipment; unplanned venting is mainly for the station, in the case of overpressure, fire, etc., to discharge the flammable media accumulated in the pipelines and equipment as soon as possible.

[0004] Since hydrogen has a low ignition energy and a special reverse coke soup effect, in the early stage of high-pressure release, the high-speed released fluid will cause instantaneous compression of the local gas downstream of the vent valve in the venting system, forming a high shock wave, thereby causing temperature rise (reaching the gas auto-ignition temperature) and possibly causing hydrogen to spontaneously ignite downstream of the vent valve (which can be called "diffusion auto-ignition"), which in turn causes hydrogen to deflagrate in the vent pipe of the venting system; for the venting system originally designed for the release mode (i.e., no ignition, direct release to the atmosphere), it may deviate from the design intent, causing the release riser to become a "torch". Especially for unplanned venting systems, more attention should be paid to the problem of untimely or uneconomical replacement before venting. Summary of the invention

[0005] The inventors of the present application have found that there is currently little research on the prevention and control of spontaneous combustion of hydrogen venting systems, and the existing technology mainly uses air isolation measures to continuously inject non-combustible gases to perform long-term, real-time replacement of the venting system, thereby achieving the spontaneous combustion prevention function of the hydrogen venting system. However, this type of air isolation measure has serious resource consumption and poor economic efficiency.

[0006] In view of the above problems, the present invention is proposed to provide a spontaneous combustion prevention system and method for a hydrogen station venting system that overcomes the above problems or at least partially solves the above problems.

[0007] The embodiment of the present invention provides a spontaneous combustion prevention system for a hydrogen station venting system, including: a venting pipeline isolation system;

[0008] The venting isolation system comprises: a venting main line for connecting the hydrogen station and the venting riser, the venting main line is used to connect one end of the hydrogen station to the gas source branch, and the gas source branch is used to connect the gas source device;

[0009] The gas source branch is provided with an injection shutoff valve; the end of the vent main line for connecting to the vent riser is provided with a replacement branch, and the replacement branch is provided with a replacement outlet shutoff valve; so that the non-flammable gas of the gas source device is controlled to be injected into the vent main line through the injection shutoff valve and the replacement outlet shutoff valve to replace the gas in the vent main line;

[0010] The vent main line downstream of the replacement branch line includes at least two parallel vent branches, one of which is provided with a bypass shut-off valve, and the other vent branches are provided with bursting discs; the bypass shut-off valve is used to allow the gas in the vent main line to be discharged from the vent riser through the bypass shut-off valve under planned venting conditions and normal operating conditions of the hydrogen station; the bursting disc is used to rupture under unplanned venting conditions, so that the gas released from the hydrogen station is mixed with non-flammable gas in the vent main line and then discharged from the vent riser through the bursting discs.

[0011] In an optional embodiment, the spontaneous combustion prevention system of the hydrogen station venting system provided by the embodiment of the present invention further includes: a plurality of buffer branches;

[0012] The buffer branch is used to communicate with the bottom of the venting riser, and a plurality of the buffer branches are sequentially arranged along the radial direction of the venting riser to buffer the gas entering the venting riser from the venting main line.

[0013] In an optional embodiment, the spontaneous combustion prevention system of the hydrogen station venting system provided in the embodiment of the present invention also includes: an anti-backflow system; the anti-backflow system is used to communicate with the drain port of the venting riser to discharge the accumulated liquid in the venting riser through the anti-backflow system.

[0014] In an optional embodiment, the anti-backflow system includes: a first liquid discharge cut-off valve, a relay pipeline and a second liquid discharge cut-off valve connected in sequence;

[0015] The first liquid discharge cut-off valve is in communication with the liquid discharge port of the venting riser.

[0016] In an optional embodiment, the spontaneous combustion prevention system of the hydrogen station venting system provided in the embodiment of the present invention further includes a sampling device, which is connected to the replacement outlet shut-off valve to sample the gas in the venting main line.

[0017] In an optional embodiment, a venting element is provided between the hydrogen station and the venting main line;

[0018] The venting element comprises: an overpressure safety valve, an emergency relief valve and a regulating relief valve which are connected in parallel with each other and communicated with the hydrogen station and the venting main pipeline.

[0019] In an optional embodiment, a pressure transmitter is further provided on the main vent line to detect the sealing performance of the main vent line.

[0020] In an optional embodiment, the main vent line is made of carbon steel.

[0021] In an optional embodiment, the preset bursting pressure of the bursting disc is 0.1-0.2 barg.

[0022] Based on the same inventive concept, an embodiment of the present invention provides a method for realizing spontaneous combustion prevention and control of a hydrogen station venting system by using the spontaneous combustion prevention and control system of the hydrogen station venting system described above; comprising:

[0023] Before the normal gas supply at the hydrogen station, open the injection shutoff valve and the displacement outlet shutoff valve, and inject non-flammable gas into the vent main line until the oxygen content of the gas discharged from the displacement outlet shutoff valve is lower than the preset oxygen content threshold, and then close the injection shutoff valve and the displacement outlet shutoff valve;

[0024] Under normal gas supply conditions at the hydrogen station, the injection shut-off valve and bypass shut-off valve are opened at preset intervals to replace the gas in the vent main pipeline with non-combustible gas;

[0025] In the unplanned venting state, the vented gas enters the vent main line through the overpressure safety valve or emergency relief valve of the venting element, mixes with the non-combustible gas in the vent main line, and after reaching the preset bursting pressure of the bursting disc, flows from the vent main line into the vent riser for discharge;

[0026] When venting is planned, open the bypass shutoff valve and then open the relief valve of the venting element to allow the vented gas to enter the venting main line and mix with the non-flammable gas in the venting main line, and then flow from the bypass shutoff valve into the venting riser and be discharged.

[0027] In an optional embodiment, the spontaneous combustion prevention method provided by the embodiment of the present invention further includes: the gas flowing from the vent main line into the vent riser is discharged from the vent riser after being buffered by the buffer branch.

[0028] In an optional embodiment, the spontaneous combustion prevention and control method provided by the embodiment of the present invention, after the amount of accumulated liquid at the bottom of the vent riser is higher than a preset upper limit of the accumulated liquid amount, opens the first liquid discharge shut-off valve to allow the accumulated liquid in the vent riser to flow into the relay pipeline until the amount of accumulated liquid at the bottom of the vent main pipeline is lower than the preset lower limit of the accumulated liquid amount, closes the first liquid discharge shut-off valve, then opens the second liquid discharge shut-off valve to discharge the accumulated liquid in the relay pipeline, and closes the second liquid discharge shut-off valve.

[0029] In an optional embodiment, the spontaneous combustion prevention method provided in the embodiment of the present invention further includes: using a pressure transmitter to detect the sealing performance of the vent main line.

[0030] The beneficial effects of the above technical solution provided by the embodiment of the present invention include at least:

[0031] The spontaneous combustion prevention system provided in the embodiment of the present invention is designed according to the operating characteristics of the hydrogen station and the feature that hydrogen is prone to spontaneous combustion after leakage, and can meet the needs of planned and unplanned venting of the venting system of the hydrogen station; before the normal operation of the hydrogen station, non-combustible gas is injected into the venting main line to replace the gas in the venting main line. After the gas in the venting main line is replaced with non-combustible gas, the injection shut-off valve, bypass shut-off valve and replacement outlet shut-off valve are in a closed state, and the bursting disc provided in combination provides a long-term sealing effect for the non-combustible gas in the venting main line. When the hydrogen station is operating normally, it only needs to be closed within a preset time. It is sufficient to replace the gas in the venting main line. Compared with the existing air isolation measures of performing long-term and real-time replacement of the venting system by continuous injection of non-combustible gas, the venting pipeline isolation system proposed in the embodiment of the present invention optimizes the continuous replacement into an intermittent replacement + long-term static mode, which greatly reduces the loss of non-combustible gas and the energy consumption when introducing non-combustible gas, and increases the economic benefits; and in the venting state, after the gas in the hydrogen station is released, it will be mixed with the non-combustible gas enclosed in the venting main line, thereby achieving the effect of isolating the air after the gas is discharged from the release point, essentially reducing the possibility of hydrogen spontaneous combustion. At the same time, with the help of the non-combustible gas injection function provided by the venting pipeline isolation system of the present invention, when the venting system selects the venting torch, in the middle and late stages of the discharge, the non-combustible gas can be filled into the venting main line by opening the injection shut-off valve and the bypass shut-off valve, thereby providing a positive pressure seal for the venting main line in the middle and late stages of the venting, eliminating the flame arrester, and making the structure of the entire venting system simpler; and it can prevent and control the flashback problem that may be caused by the reduction in the flow rate of the lowered medium.

[0032] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description, claims, and drawings.

[0033] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0035] Figure 1 Schematic diagram of a spontaneous combustion prevention system of a hydrogen station venting system in an embodiment of the present invention.

[0036] Description of Reference Numerals

[0037] 1-vent main line, 2-gas source branch, 3-displacement branch, 4-vent branch, 5-buffer branch, 6-anti-backflow system, 7-vent element, 8-vent riser, 9-pressure transmitter;

[0038] 21-injection shut-off valve, 31-replacement outlet shut-off valve, 41-bursting disc, 42-spare bursting disc, 43-bypass shut-off valve; 61-first liquid discharge shut-off valve, 62-relay pipeline, 63-third liquid discharge shut-off valve; 71-overpressure safety valve, 72-emergency relief valve, 73-regulating relief valve. DETAILED DESCRIPTION

[0039] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0040] In order to overcome the deficiencies of the prior art and further improve the spontaneous combustion prevention technology of the hydrogen station venting system, the embodiment of the present invention provides a spontaneous combustion prevention system for the hydrogen station venting system from the perspectives of the spontaneous combustion principle of the hydrogen venting system and efficient response.

[0041] Reference Figure 1 As shown, the spontaneous combustion prevention system of the hydrogen station venting system provided by the embodiment of the present invention includes: a venting pipeline isolation system;

[0042] The venting isolation system includes: a venting main line 1 for connecting the hydrogen station and the venting riser, the venting main line 1 is used to connect one end of the hydrogen station to the gas source branch line 2, and the gas source branch line 2 is used to connect the gas source device;

[0043] An injection shutoff valve 21 is provided on the gas source branch line 2; a displacement branch line 3 is provided on one end of the vent main line 1 for connecting to the vent riser 8, and a displacement outlet shutoff valve 31 is provided on the displacement branch line 3; so that the non-flammable gas of the gas source device is injected into the vent main line 1 through the injection shutoff valve 21 and the displacement outlet shutoff valve 31 to replace the gas in the vent main line 1;

[0044] The vent main line 1 downstream of the replacement branch includes at least two parallel vent branches 4, one of which is provided with a bypass shut-off valve 43, and the other vent branches are provided with bursting discs 41; the bypass shut-off valve 43 is used to discharge the gas in the vent main line 1 from the vent riser 8 through the bypass shut-off valve 43 under planned venting conditions and normal operation of the hydrogen station; the bursting disc 41 is used to rupture under unplanned venting conditions, so that the gas released from the hydrogen station is mixed with non-flammable gas in the vent main line 1 and then discharged from the vent riser through the bursting disc 41.

[0045] The spontaneous combustion prevention system provided in the embodiment of the present invention is designed according to the operating characteristics of the hydrogen station and the feature that hydrogen is prone to spontaneous combustion after leakage, and can meet the needs of planned and unplanned venting of the venting system of the hydrogen station; before the normal operation of the hydrogen station, non-combustible gas is injected into the venting main line to replace the gas (i.e., air) in the venting main line. After the gas in the venting main line is replaced with non-combustible gas, the injection shut-off valve, bypass shut-off valve and replacement outlet shut-off valve are in a closed state, and the bursting disc provided in combination provides a long-term sealing effect for the non-combustible gas in the venting main line. When the hydrogen station is operating normally, it is only necessary to replace the gas in the venting main line at a preset time to prevent To prevent the occurrence of internal leakage in the replacement outlet shut-off valve, bypass relief valve, etc., which allows other gases to enter the venting main line, compared with the existing air isolation measures of long-term and real-time replacement of the venting system by continuous injection of non-combustible gas, the venting pipeline isolation system proposed in the embodiment of the present invention optimizes the continuous replacement to an intermittent replacement + long-term static mode, which greatly reduces the loss of non-combustible gas and the energy consumption when introducing non-combustible gas, and increases the economic benefit; and in the venting state, after the gas in the hydrogen station is released, it will mix with the non-combustible gas enclosed in the venting main line, thereby achieving the effect of isolating the air after the gas is discharged from the release point, essentially reducing the possibility of hydrogen spontaneous combustion. At the same time, with the help of the non-combustible gas injection function provided by the venting pipeline isolation system of the present invention, when the venting system selects the venting torch, in the middle and late stages of the discharge, the non-combustible gas can be filled into the venting main line by opening the injection shut-off valve and the bypass shut-off valve, thereby providing a positive pressure seal for the venting main line in the middle and late stages of the venting, eliminating the flame arrester, and making the structure of the entire venting system simpler; and it can prevent and control the flashback problem that may be caused by the reduction in the flow rate of the lowered medium.

[0046] Specifically, the venting pipeline isolation system is used to isolate the non-combustible gas in the venting main pipeline for a long time, provide non-combustible gas mixing for the front end of hydrogen released during unplanned venting, and isolate it from the air, so as to prevent the high-pressure venting gas from diffusing and spontaneously igniting due to medium compression and temperature rise, or friction between the medium and the pipeline in the initial stage of unplanned venting.

[0047] In the vent pipeline isolation system provided by the embodiment of the present invention, the injection shut-off valve 21 and the replacement outlet shut-off valve 31 can be carbon steel ball valves and can be manually controlled valves. During use, the injection shut-off valve 21 and the replacement outlet shut-off valve 31 are in a normally closed state, wherein the injection shut-off valve is only opened when non-combustible gas is injected into the vent main pipeline, and is used to control the gas source device to inject non-combustible gas into the vent main pipeline; the replacement outlet shut-off valve 3 is generally opened when the gas in the vent main pipeline is initially replaced under normal operating conditions of the hydrogen station.

[0048] Furthermore, the vent main line 1 connects the hydrogen station and the vent riser to provide a flow channel for the vent gas; the vent main line 1 can be made of carbon steel. Since non-flammable gas is sealed in the vent main line 1 for a long time, the gas released at the hydrogen station will mix with the non-flammable gas in the vent main line after entering the vent main line. Therefore, in the process of gas flow, the spontaneous combustion phenomenon caused by the friction between the released gas and the pipe wall of the vent main line can be reduced. Therefore, the material requirements for the vent main line are reduced, and the vent main line set can be selected to be made of carbon steel to replace the stainless steel material in the prior art, which further improves the economic benefits and reduces the investment.

[0049] Optionally, the spontaneous combustion prevention system of the embodiment of the present invention may further include a sampling device (not shown in the figure), which is connected to the replacement outlet shut-off valve 31 to sample the gas in the vent main line; before the normal operation of the hydrogen station, when the injection shut-off valve 21 and the replacement outlet shut-off valve 31 are opened to replace the gas in the vent main line, after the preset replacement time, the gas in the vent main line is sampled from the replacement outlet shut-off valve 31 using the sampling device, and the sampled gas is subjected to component detection. When the oxygen content in the gas discharged from the replacement outlet shut-off valve 31 is lower than the preset oxygen content value, it indicates that the replacement of the gas in the vent main line is completed, and the injection shut-off valve 21 and the replacement outlet shut-off valve 31 are closed at this time; preferably, the preset replacement time is not less than 5 minutes, and the preset oxygen content is a volume fraction of oxygen content lower than 1% of the total gas content. Specifically, the specific values ​​of the preset replacement time and the preset oxygen content are not specifically limited in the embodiment of the present invention and can be set according to actual needs, and the sampling device can specifically be a sampling tube.

[0050] Among them, the gas source device can be a non-combustible gas storage bottle; at the same time, the spontaneous combustion prevention system of the embodiment of the present invention can reduce the number of replacements of non-combustible gas storage bottles, further reduce the spontaneous combustion of hydrogen caused by the replacement of non-combustible gas storage bottles, and improve the reliability of the spontaneous combustion prevention system. And the injected non-combustible gas can preferably be carbon dioxide or nitrogen.

[0051] At the same time, the spontaneous combustion prevention and control system provided in the embodiment of the present invention may be provided with a plurality of bursting discs 41. The bursting discs 41 are used to rupture after the upstream hydrogen station is discharged, and to guide the discharged gas into the venting riser. Before the hydrogen station is discharged, the gas in the venting main line 1 is kept from being discharged into the venting riser 8, so as to prevent the air from flowing back into the venting main line through the venting riser. The structure of providing a plurality of bursting discs may provide spare bursting discs, so as to prevent the problem of unplanned venting failure caused by the failure of a certain bursting disc to rupture during unplanned venting, and improve the reliability of the venting rupture of the bursting disc. Among them, the embodiment of the present invention does not specifically limit the number of parallel venting branches. Preferably, it may be set to at least 3. For details, refer to Figure 1 As shown, a bypass shut-off valve 43 is provided on one of the vent branches, and a bursting disc 41 and a spare bursting disc 42 are provided on the other two vent branches; further, the bursting disc can be a micro-positive pressure bursting disc, and the preset rupture pressure of each bursting disc can be 0.1-0.2 barg.

[0052] The bypass shut-off valve 43 can be a manual ball valve, which is arranged in parallel with the bursting disc 41 and the spare bursting disc 42, and is in a normally closed working state. It is opened when the gas in the venting main line 1 is periodically replaced. That is, when the gas is replaced, the replacement outlet shut-off valve 31 is closed and the bypass shut-off valve 43 is used for replacement. The purpose is that if unplanned venting occurs during the gas replacement process, the unplanned vented gas can flow through the venting main line 1 and be discharged from the venting riser, thereby avoiding the venting gas from being discharged from the replacement outlet shut-off valve and causing danger; the reliability of the entire system is further improved.

[0053] Optionally, a pressure transmitter 9 may be provided on the vent main line 1 to detect the sealing performance of the vent main line 1; it is used to characterize the sealing performance of the bursting disc 41, the spare bursting disc 42, and the bypass shut-off valve 43, so as to prevent the vent main line 1 from losing its sealing effect on the non-flammable gas inside it due to accidental rupture of the bursting disc 41 or looseness of the bypass shut-off valve 43, thereby causing the vent system to lose its self-ignition prevention function. Specifically, the pressure transmitter is provided before the replacement branch 4, and the monitoring pressure value of the pressure transmitter 9 can be set to 0.1 barg, that is, when the pressure detected by the pressure transmitter is less than 0.1 barg, it indicates that the gas pressure in the vent main line 1 is at normal pressure, further indicating that the vent main line may be in a state of connection with the outside world. At this time, the vent line isolation system needs to be inspected and repaired to ensure that the vent main line 1 has a sealing effect on the non-flammable gas inside it, further improving the reliability of the vent line isolation system.

[0054] In an optional embodiment, the spontaneous combustion prevention system provided by the embodiment of the present invention may further include: a plurality of buffer branches 5;

[0055] The buffer branch 5 is used to communicate with the bottom of the venting riser 8, and multiple buffer branches 5 are sequentially arranged along the radial direction of the venting riser 8 to buffer the gas entering the venting riser 8 from the venting main line 1.

[0056] A plurality of buffer branches 5 constitute a vent pipeline discharge buffer system, which is used to provide a buffer for the gas flowing from the vent main line 1 into the vent riser 8 during the venting initial stage and venting process of planned venting and unplanned venting, that is, the gas entering the vent riser 8 from the vent main line 1 will flow through the buffer branch 5, and after being buffered by the gas in the buffer branch 5, the flow path is changed and then discharged from the vent riser. Compared with the method of directly colliding with the vent riser wall after entering the vent riser and then changing the flow path, the buffer branch 5 absorbs the kinetic energy of the high-speed vent gas when it is transferred from the horizontal vent main line to the vertical vent riser, slowing down the vibration and friction of the vented gas under high-speed impact, and reducing the probability of sparks under high flow diversion. Specifically, the buffer branch 5 may include a buffer pipeline and a blind plate arranged at the end of the buffer pipeline.

[0057] Optionally, the spontaneous combustion prevention system of the embodiment of the present invention further includes: an anti-backflow system 6; the anti-backflow system 6 is used to communicate with the drain port of the venting riser to discharge the accumulated liquid in the venting riser through the anti-backflow system.

[0058] Specifically, the anti-backflow system includes: a first liquid discharge cut-off valve 61, a relay pipeline 62 and a second liquid discharge cut-off valve 63 which are connected in sequence;

[0059] The first liquid discharge shut-off valve is connected to the liquid discharge port of the vent riser.

[0060] Among them, the first drain shutoff valve 61 and the second drain shutoff valve 63 can be manual ball valves, which are in a normally closed state and are only opened when draining the vent riser. In use, the first drain shutoff valve 61 and the second drain shutoff valve 63 are not opened at the same time.

[0061] Under normal operation of the hydrogen station, the accumulated liquid at the bottom of the venting riser (or venting flare) is discharged manually. When the amount of accumulated liquid at the bottom of the venting riser reaches the preset upper limit of the accumulated liquid amount (after reaching the upper limit of the liquid level gauge), the first liquid discharge shut-off valve 61 is first opened, and the accumulated liquid is discharged into the relay pipeline 62. When the amount of liquid collected at the bottom of the venting riser 8 is lower than the preset lower limit of the accumulated liquid amount (the lower limit of the liquid level gauge), the first liquid discharge shut-off valve 61 is closed; the second liquid discharge shut-off valve 63 is opened to discharge the accumulated liquid in the relay pipeline 62, and then the second liquid discharge shut-off valve 63 is closed. This ensures that the upstream of the first liquid discharge shut-off valve 61 remains liquid-tight, and the two shut-off valves (the first liquid discharge shut-off valve 61 and the second liquid discharge shut-off valve 63) of the relay pipeline are not opened at the same time, to avoid the problem of outside air entering the venting riser through the opened first liquid discharge shut-off valve 61 and the second liquid discharge shut-off valve 63 into the venting riser due to the low pressure in the bottom area of ​​the venting riser during high-speed discharge, thereby causing the mixing of hydrogen and air in the riser, and can prevent the venting system from backflow.

[0062] Further, the spontaneous combustion prevention system of the embodiment of the present invention refers to Figure 1 As shown, a venting element 7 is provided between the hydrogen station and the venting main line 1;

[0063] The venting element 7 comprises: an overpressure safety valve 71, an emergency relief valve 72 and a regulating relief valve 73 which are connected in parallel with each other and communicated with the hydrogen station and the venting main pipeline.

[0064] Specifically, the gas source branch 2 is arranged downstream of the venting element 7; wherein the overpressure safety valve 71 and the emergency relief valve 72 are in an open state during unplanned venting, at which time the gas released from the hydrogen station flows through the overpressure safety valve 71 or the emergency relief valve 72 and flows into the venting main line and mixes with the gas in the venting main line to suppress its diffusion and spontaneous combustion; when the pressure of the mixed gas is slightly higher than the preset rupture pressure of the bursting disc, the mixed gas enters the venting riser to achieve safe discharge and treatment, and a limiting flow orifice plate can also be arranged behind the emergency relief valve 72 so that the pressure of the gas released from the hydrogen station can be released after flowing through the limiting flow orifice plate.

[0065] The regulating relief valve 73 is opened when the venting is planned, and the flow rate of the gas during the planned venting can be controlled by controlling the opening of the regulating relief valve 73. At this time, the bypass shut-off valve 43 is also in an open state. The gas released from the hydrogen station flows through the regulating relief valve 73 and enters the venting main line. The released front-end gas is mixed with the non-combustible gas accumulated in the venting main line 1 and then flows through the opened bypass shut-off valve and is discharged from the venting riser to achieve safe discharge and treatment of the gas.

[0066] In order to overcome the shortcomings of the existing technology and further improve the spontaneous combustion prevention and control technology of the hydrogen station venting system, this paper proposes a spontaneous combustion prevention and control system and method for the hydrogen station venting system. Based on the unplanned venting characteristics of hydrogen stations and the possible spontaneous combustion of hydrogen under low-pressure venting, from the perspectives of long-term air isolation of the venting system, efficient use of replacement gas, and prevention of air entry during the venting process, a venting pipeline isolation system, a venting buffer system, an anti-backflow system, etc. are set up to avoid spontaneous combustion problems caused by medium compression and temperature rise, medium and pipeline friction, etc. in the venting main pipeline during unplanned venting of hydrogen stations. In addition, it also includes necessary station facilities that constitute the complete functions of this system, such as hydrogen stations, venting risers, venting elements, etc. It should be noted that the above elements belong to the prior art and do not belong to the innovation of the present invention.

[0067] The spontaneous combustion prevention system provided in the embodiment of the present invention has a venting line isolation system that isolates the venting main line through bursting discs and valves, etc., to ensure that the gas in the venting main line is isolated from the air (mostly non-combustible gas), and a periodic replacement function is set to prevent air from entering the venting main line due to internal leakage of the valve during normal operation of the hydrogen station, and fully ensure that the hydrogen released from the high-pressure end cannot contact the air after entering the venting main line, thereby avoiding spontaneous combustion; this method is more energy-efficient than the method of long-term supply of sealing gas. When the pressure of the venting main line exceeds the preset rupture pressure of the bursting disc, the bursting disc ruptures, but the front end of the gas passing through the bursting disc is non-combustible gas, which serves as a barrier to dispel the air downstream of the bursting disc and can also effectively prevent spontaneous combustion. In order to ensure the reliability of the bursting disc, a spare bursting disc is set. In addition, in order to ensure the function of emergency discharge when the venting line is replaced, a temporarily opened bypass shut-off valve is also set.

[0068] And because the density of hydrogen is extremely small and the venting speed is fast, it is very easy to form negative pressure inside the venting riser. For this reason, the drainage system of the venting riser is set to a double-cut-off mode (the first drainage cut-off valve and the second drainage cut-off valve), and the two cannot be opened at the same time to avoid the bottom of the venting riser being directly connected to the atmosphere during the drainage process, causing the hidden danger of atmospheric back suction.

[0069] Based on the same inventive concept, an embodiment of the present invention further provides a natural prevention method using the spontaneous combustion prevention system of the above-mentioned hydrogen station venting system, comprising the following steps:

[0070] Before the normal operation of the hydrogen station, open the injection shutoff valve and the displacement outlet shutoff valve, inject non-flammable gas into the vent main line until the oxygen content of the gas discharged from the displacement outlet shutoff valve is lower than the preset oxygen content threshold, and then close the injection shutoff valve and the displacement outlet shutoff valve;

[0071] When the hydrogen station is in normal operation, the injection shut-off valve and bypass shut-off valve are opened at preset intervals to replace the gas in the vent main pipeline with non-combustible gas;

[0072] In the unplanned venting state, the vented gas enters the vent main line through the overpressure safety valve or emergency relief valve of the venting element, mixes with the non-combustible gas in the vent main line, and after reaching the preset bursting pressure of the bursting disc, flows from the vent main line into the vent riser for discharge;

[0073] When venting is planned, open the bypass shutoff valve and then open the relief valve of the venting element to allow the vented gas to enter the venting main line and mix with the non-flammable gas in the venting main line, and then flow from the bypass shutoff valve into the venting riser and be discharged.

[0074] Specifically, when replacing the gas in the vent main line before the normal operation of the hydrogen station, the duration should be no less than 5 minutes, and the gas in the vent main line should be tested for components by sampling at the outlet of the replacement outlet shut-off valve. The gas replacement is qualified if the volume fraction of oxygen content in the discharged medium is lower than 1% of the total gas content.

[0075] When the hydrogen station is in normal operation, the preset time for replacing the gas in the vent main line can be once a week.

[0076] The spontaneous combustion prevention method provided in an embodiment of the present invention further includes: the vented gas flowing from the vent main line into the vent riser is buffered by the buffer branch line and then discharged from the vent riser.

[0077] The spontaneous combustion prevention method provided by the embodiment of the present invention further includes: after the amount of accumulated liquid at the bottom of the venting riser is higher than the preset upper limit of the accumulated liquid, opening the first drain shutoff valve to allow the accumulated liquid in the venting riser to flow into the relay pipeline until the amount of accumulated liquid at the bottom of the venting main pipeline is lower than the preset lower limit of the accumulated liquid, closing the first drain shutoff valve, then opening the second drain shutoff valve to discharge the accumulated liquid in the relay pipeline, and closing the second drain shutoff valve to discharge the liquid collected at the bottom of the venting riser. Specifically, the amount of accumulated liquid in the venting riser can be measured by a liquid level meter arranged at the bottom of the venting riser.

[0078] The spontaneous combustion prevention method provided by the embodiment of the present invention further includes: using a pressure transmitter to detect the sealing performance of the vent main line.

[0079] Regarding the natural prevention method of the spontaneous combustion prevention system of the hydrogen station venting system in the above-mentioned embodiment, the specific manner in which each module performs the operation has been described in detail in the embodiment of the spontaneous combustion prevention system, and will not be elaborated here.

[0080] The spontaneous combustion prevention system and method provided by the embodiment of the present invention provides safety assurance from aspects such as isolating air in the initial stage of discharge, slowing down the steering impact during discharge, and avoiding the back-inhalation of air during discharge, thus forming a more economical and reliable spontaneous combustion prevention system for the venting system of medium and high pressure hydrogen stations. Specifically, it is as follows:

[0081] (1) Scientific setting

[0082] In view of the operating characteristics of hydrogen stations and the fact that hydrogen is prone to spontaneous combustion after being released, the present invention modifies the existing discharge method from the perspectives of isolating air, reducing static electricity caused by steering collisions, premixing the discharged hydrogen and non-combustible gases, and preventing the introduction of air into the drain port, thereby greatly reducing the probability of spontaneous combustion caused by hydrogen release in the venting system. For example, the venting pipeline isolation system provided provides a long-term sealing effect for non-combustible gases, achieves the effects of isolating air and fully mixing with non-combustible gases after hydrogen is discharged from the release point, and essentially reduces the possibility of spontaneous combustion; the venting pipeline anti-air backflow system provided is targeted for hydrogen with a relatively high discharge flow rate (the sound velocity of hydrogen is extremely high, which can reach 1300m / s), and adopts a strategy of strengthening protection to avoid the problem of external air inhaling into the venting system caused by excessively fast hydrogen flow rate.

[0083] (2) Good economic performance

[0084] Compared with the traditional spontaneous combustion control mode, the vent pipe isolation system proposed in the present invention optimizes the continuous purge into an intermittent purge + long-term static mode, which greatly reduces the non-combustible gas consumption and the energy consumption of introducing non-combustible gas; further, due to the support of the essential isolation of the present invention, the vent system can be selected to be made of carbon steel, which reduces the investment; at the same time, with the help of the non-combustible gas injection function provided by the vent pipe isolation system of the present invention, in the vent ignition scenario, it can be used to provide the vent main line gas sealing function in the later stage of venting, and the flame arrester can be eliminated.

[0085] (3) Promoting technological development

[0086] The present invention focuses on the problem of spontaneous combustion prevention and control of hydrogen station venting systems, which is in line with the development plan for efficient utilization of hydrogen energy. In the absence of relevant public information, it can serve as a support for effectively promoting technological progress in the safe operation of such stations, and has good social benefits while ensuring safety.

[0087] Regarding the device in the above embodiment, the specific manner of performing the operation has been described in detail in the embodiment of the method, and will not be elaborated here.

[0088] The above description includes examples of one or more embodiments. Of course, it is impossible to describe all possible combinations of components or methods for the purpose of describing the above embodiments, but it should be recognized by those skilled in the art that the various embodiments may be further combined and arranged. Therefore, the embodiments described herein are intended to cover all such changes, modifications and variations that fall within the scope of protection of the appended claims. In addition, with respect to the term "comprising" used in the specification or claims, the word is covered in a manner similar to the term "including", just as "including," is explained as a transitional word in the claims. In addition, any term "or" used in the specification of the claims is intended to mean "non-exclusive or".

[0089] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A spontaneous combustion prevention system for a hydrogen station venting system, characterized in that: include: Vent line isolation system; The venting isolation system comprises: a venting main line for connecting the hydrogen station and the venting riser, the venting main line is used to connect one end of the hydrogen station to the gas source branch, and the gas source branch is used to connect the gas source device; The gas source branch is provided with an injection shutoff valve; the end of the vent main line for connecting to the vent riser is provided with a replacement branch, and the replacement branch is provided with a replacement outlet shutoff valve; so that the non-flammable gas of the gas source device is controlled to be injected into the vent main line through the injection shutoff valve and the replacement outlet shutoff valve to replace the gas in the vent main line; The vent main line downstream of the replacement branch line includes at least two parallel vent branches, one of which is provided with a bypass shut-off valve, and the other vent branches are provided with bursting discs; the bypass shut-off valve is used to allow the gas in the vent main line to be discharged from the vent riser through the bypass shut-off valve under planned venting conditions and normal operating conditions of the hydrogen station; the bursting disc is used to rupture under unplanned venting conditions, so that the gas released from the hydrogen station is mixed with non-flammable gas in the vent main line and then discharged from the vent riser through the bursting discs.

2. The spontaneous combustion prevention system of the hydrogen station venting system according to claim 1, characterized in that: Also includes: Multiple buffer branches; The buffer branch is used to communicate with the bottom of the venting riser, and a plurality of the buffer branches are sequentially arranged along the radial direction of the venting riser to buffer the gas entering the venting riser from the venting main line.

3. The spontaneous combustion prevention system according to claim 1, characterized in that: Also includes: Anti-backflow system; the anti-backflow system is used to communicate with the discharge port of the venting riser to discharge the accumulated liquid in the venting riser through the anti-backflow system.

4. The spontaneous combustion prevention system according to claim 3, characterized in that: The anti-backflow system comprises: a first liquid discharge cut-off valve, a relay pipeline and a second liquid discharge cut-off valve connected in sequence; The first liquid discharge cut-off valve is in communication with the liquid discharge port of the venting riser.

5. The spontaneous combustion prevention system according to claim 1, characterized in that: It also includes a sampling device, which is communicated with the replacement outlet cut-off valve to sample the gas in the venting main pipeline.

6. The spontaneous combustion prevention system of the hydrogen station venting system according to claim 1, characterized in that: A venting element is provided between the hydrogen station and the venting main line; The venting element comprises: an overpressure safety valve, an emergency relief valve and a regulating relief valve which are connected in parallel with each other and communicated with the hydrogen station and the venting main pipeline.

7. The spontaneous combustion prevention system according to claim 1, characterized in that: The main vent line is also provided with a pressure transmitter to detect the sealing performance of the main vent line.

8. The spontaneous combustion prevention system according to claim 1, characterized in that: The main vent pipe is made of carbon steel.

9. The spontaneous combustion prevention system according to any one of claims 1 to 8, characterized in that: The preset bursting pressure of the bursting disc is 0.1-0.2 barg.

10. A method for preventing and controlling spontaneous combustion of a hydrogen station venting system, characterized in that: The method is implemented by using the spontaneous combustion prevention system of the hydrogen station venting system as described in any one of claims 1 to 9; comprising: Before the normal gas supply at the hydrogen station, open the injection shutoff valve and the displacement outlet shutoff valve, and inject non-flammable gas into the vent main line until the oxygen content of the gas discharged from the displacement outlet shutoff valve is lower than the preset oxygen content threshold, and then close the injection shutoff valve and the displacement outlet shutoff valve; Under normal gas supply conditions at the hydrogen station, the injection shut-off valve and bypass shut-off valve are opened at preset intervals to replace the gas in the vent main pipeline with non-combustible gas; In the unplanned venting state, the vented gas enters the vent main line through the overpressure safety valve or emergency relief valve of the venting element, mixes with the non-combustible gas in the vent main line, and after reaching the preset bursting pressure of the bursting disc, flows from the vent main line into the vent riser for discharge; When venting is planned, open the bypass shutoff valve and then open the relief valve of the venting element to allow the vented gas to enter the venting main line and mix with the non-flammable gas in the venting main line, and then flow from the bypass shutoff valve into the venting riser and be discharged.

11. The spontaneous combustion prevention method according to claim 10, characterized in that: Also includes: The gas flowing into the vent riser from the vent main line is buffered by the buffer branch and then discharged from the vent riser.

12. The spontaneous combustion prevention method according to claim 11, characterized in that: Also includes: After the amount of accumulated liquid at the bottom of the venting riser is higher than the preset upper limit of the accumulated liquid volume, open the first drain shut-off valve to allow the accumulated liquid in the venting riser to flow into the relay pipeline until the amount of accumulated liquid at the bottom of the venting main pipeline is lower than the preset lower limit of the accumulated liquid volume, close the first drain shut-off valve, and then open the second drain shut-off valve to discharge the accumulated liquid in the relay pipeline, and then close the second drain shut-off valve.

13. The spontaneous combustion prevention method according to any one of claims 10 to 12, characterized in that: Also includes: The pressure transmitter is used to detect the sealing performance of the main vent line.

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