Pipeline safety isolation and maintenance valve group device for hydrogen

Abstract

The present application relates to hydrogen energy transportation and pipeline repair safety technical field, specifically for hydrogen pipeline safety isolation repair valve group equipment, including for connecting upstream hydrogen pipeline gas pipeline, first shunt and second shunt, first shunt and second shunt are fixedly connected with gas pipeline through tee, first shunt and second shunt are respectively provided with first stop valve;The present application adopts two groups of parallel type hydrogen removal unit, independent control is realized through connecting unit and third stop valve, can form one spare, redundant hydrogen removal system, when main hydrogen removal unit appears catalyst failure, blockage, poisoning or needs maintenance replacement, control system can quickly close main circuit, open standby circuit, realize no shutdown, uninterrupted, no leakage switching, completely solve the problem that traditional single channel hydrogen removal equipment is paralyzed once fails, ensure that hydrogen removal operation continues stably, improve the intrinsic safety level of hydrogen pipeline repair from structure.

Description

Technical Field

[0001] This invention relates to the field of hydrogen energy transmission and pipeline maintenance safety technology, specifically to a safety isolation and maintenance valve assembly for hydrogen pipelines. Background Technology

[0002] Hydrogen is widely used as a clean energy source in industry, hydrogen storage and transportation, hydrogen refueling stations, and pipeline transportation systems. However, its flammable and explosive properties pose extremely high safety risks: the explosive limits of hydrogen in air are 4.0% to 75.6%, and it can be ignited and exploded with very little energy. When hydrogen pipelines, skid-mounted stations, valve groups, and other facilities are shut down for maintenance, a large amount of hydrogen will remain inside the pipeline. If it is directly disassembled, cut, or repaired, an explosion is very likely to occur, causing casualties and significant property damage. Current technology usually uses nitrogen purging and replacement methods. This method involves introducing a large amount of nitrogen into the pipeline to dilute and replace the residual hydrogen.

[0003] However, this method has some shortcomings: the hydrogen-nitrogen mixture is directly emitted into the atmosphere during the purging process, which not only wastes hydrogen resources but also poses environmental pollution and safety hazards to the surrounding area. The purging effect is difficult to monitor in real time, and operators cannot accurately determine whether the hydrogen concentration in the pipeline has truly dropped to a safe level. They usually rely on experience to estimate, which poses a significant risk of human error. Therefore, hydrogen pipeline safety isolation and maintenance valve group equipment is needed to improve the above problems. Summary of the Invention

[0004] To address the issues of direct emission of hydrogen-nitrogen mixture into the atmosphere during purging, which not only wastes hydrogen resources but also poses environmental pollution and safety hazards to surrounding areas, but also makes it difficult to monitor purging effectiveness in real time and for operators to accurately determine whether the hydrogen concentration in the pipeline has truly dropped to a safe level, often relying on experience-based estimations that carry a significant risk of human error, this invention provides a safety isolation and maintenance valve assembly for hydrogen pipelines to solve the aforementioned problems.

[0005] To achieve the above objectives, the present invention provides the following technical solution: Hydrogen pipeline safety isolation and maintenance valve assembly equipment, including: An inlet pipe used to connect to the upstream hydrogen pipeline.

[0006] The first and second split pipes are fixedly connected to the intake pipe via a tee, and each of the first and second split pipes is equipped with a first shut-off valve.

[0007] The air inlet of the steam-water separator is connected to the outlet of the second splitter pipe.

[0008] At least two hydrogen removal units are provided, with the inlet and outlet ends of the two units respectively fixedly connected to the same connecting unit. One of the connecting units is connected to a gas-water separator, and the outlet end of the other connecting unit is connected to a fixed hydrogen alarm. The outlet end of the fixed hydrogen alarm is fixedly connected to a discharge pipe, and the end of the discharge pipe away from the fixed hydrogen alarm is fixedly connected to a No. 2 tee pipe. One end of the No. 2 tee pipe is fixedly connected to one end of a first diversion pipe.

[0009] A gas replenishment unit is installed on the pipeline between the gas-water separator and the hydrogen removal unit.

[0010] As a preferred embodiment of the present invention, the gas outlet of the gas-water separator is provided with a conveying pipe, and a second shut-off valve and a regulating valve are sequentially provided on the conveying pipe, and the gas outlet of the conveying pipe is connected to the connecting unit.

[0011] As a preferred embodiment of the present invention, there are two hydrogen removal units, which are arranged in parallel. Each hydrogen removal unit includes an installation cylinder, an upper sealing cover disposed on the top of the installation cylinder, a lower sealing cover disposed on the bottom of the installation cylinder, and a grid support plate, a honeycomb hydrogen removal plate, and a filter screen arranged sequentially from top to bottom inside the installation cylinder. The outer wall of the mounting cylinder is fixedly fitted with an input pipe and an output pipe that communicate with the inside of the mounting cylinder, and the input pipe and the output pipe are arranged one at the bottom and one at the top.

[0012] As a preferred embodiment of the present invention, a drain pipe is provided at the bottom of the lower sealing cover, and a drain valve is provided on the drain pipe.

[0013] As a preferred embodiment of the present invention, the mounting cylinder is further provided with an annular support plate. There are two annular support plates. The grid support plate and the filter screen are respectively placed on the annular support plates. The grid support plate is located above the filter screen. The input pipe is located between the grid support plate and the filter screen. The output pipe is located above the honeycomb hydrogen removal plate. The honeycomb hydrogen removal plate has a multi-layer structure.

[0014] As a preferred embodiment of the present invention, the connecting unit includes two connecting pipes, each of which is fixedly equipped with a third shut-off valve, and the two third shut-off valves are fixedly connected to a No. 1 tee pipe.

[0015] The connection unit has two parts. The output end of the No. 1 three-way pipe of one of the connection units is fixedly connected to the delivery pipe, and the other part is fixedly connected to the exhaust pipe, which is fixedly connected to the inlet end of the fixed hydrogen alarm.

[0016] The two connecting pipes of the two connecting units are fixedly connected to the input pipe and output pipe of the two hydrogen removal units, respectively.

[0017] As a preferred embodiment of the present invention, the gas replenishment unit includes a gas storage tank, a hydrogen supply pipe, a pulse solenoid valve, and an injection pipe. The gas outlet of the gas storage tank is connected to the gas inlet of the pulse solenoid valve through the hydrogen supply pipe. The gas outlet of the pulse solenoid valve is fixedly connected to the injection pipe. The end of the injection pipe extends into the delivery pipe on the side away from the gas-water separator.

[0018] As a preferred embodiment of the present invention, the pulse solenoid valve of the air replenishment unit is an explosion-proof two-position two-way direct-acting solenoid valve, and a turbulence nozzle is provided at the end of the injection pipe. The turbulence nozzle adopts an expansion structure, with the nozzle axis forming an angle of ° to ° with the pipeline axis, and the nozzle outlet facing the airflow direction.

[0019] As a preferred embodiment of the present invention, the side wall of the fixed hydrogen alarm is fixedly connected with a column.

[0020] Compared with existing technologies, this invention adopts two sets of parallel hydrogen removal units and achieves independent control through a connection unit and a third shut-off valve, forming a hydrogen removal system with one unit in use and one in standby, which is redundant. When the main hydrogen removal unit experiences catalyst failure, blockage, poisoning, or requires maintenance and replacement, the control system can quickly shut down the main circuit and open the standby circuit, achieving uninterrupted, seamless, and leak-free switching. This completely solves the problem that traditional single-channel hydrogen removal equipment will be completely paralyzed once it fails, ensuring the continuous and stable operation of hydrogen removal and structurally improving the inherent safety level of hydrogen pipeline maintenance.

[0021] Compared with existing technologies, this invention, by setting an explosion-proof pulse gas supply unit on the delivery pipe, injects dry nitrogen or compressed air from the gas storage tank into the pipeline at high speed with a period of 30-60 seconds and a pulse width of 0.2-0.5 seconds. Combined with the oblique turbulence nozzle, it forms a strong vortex and shock wave, which can effectively flush, agitate and carry out hydrogen gas trapped in long-distance pipelines, bends, diameter changes, blind pipes, valve cavities and other locations, so that hydrogen and oxygen are mixed more evenly and the catalytic reaction efficiency is significantly improved.

[0022] Compared with existing technologies, the honeycomb hydrogen removal plate of this invention uses a Fe-Cr-Al metal honeycomb matrix to support a Pt-Pd dual noble metal catalyst. With the support of the high specific surface area of ​​the γ-Al2O3 whisker layer, it can achieve flameless catalytic oxidation of hydrogen at room temperature. It has a low ignition temperature, fast reaction rate, no open flame, and no high-temperature hot spots. The catalyst surface temperature is always lower than the auto-ignition point of hydrogen, eliminating the risk of combustion and explosion from the reaction mechanism. At the same time, the hydrogen removal efficiency is ≥99.5%, and the outlet concentration can be stably lower than 50ppm, meeting the safety standards for hydrogen pipeline maintenance. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the hydrogen removal unit of the present invention; Figure 3 This is a schematic diagram of the internal structure of the mounting cylinder of the present invention; Figure 4 This is a schematic diagram of the air replenishment unit of the present invention; Figure 5 This is a schematic diagram of the bottom structure of the hydrogen removal unit of the present invention; Figure 6 This is a schematic diagram of the top structure of the hydrogen removal unit of the present invention.

[0024] In the diagram: 1. Inlet pipe; 2. First branch pipe; 3. Second branch pipe; 4. First shut-off valve; 5. Gas-water separator; 51. Delivery pipe; 511. Second shut-off valve; 512. Regulating valve; 6. Hydrogen removal unit; 61. Mounting cylinder; 611. Input pipe; 612. Output pipe; 62. Upper sealing cover; 63. Lower sealing cover; 64. Circular support plate; 65. Grille support plate; 66. Honeycomb hydrogen removal plate; 67. Filter screen; 68. Drain pipe; 681. Drain valve; 7. Connection unit; 71. Connection pipe; 72. Third shut-off valve; 73. No. 1 tee pipe; 8. Exhaust pipe; 9. Fixed hydrogen alarm; 10. Discharge pipe; 101. No. 2 tee pipe; 11. Gas replenishment unit; 111. Gas storage tank; 112. Hydrogen delivery pipe; 113. Pulse solenoid valve; 114. Injection pipe. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0026] Example: Please refer to Figure 1-6 The hydrogen pipeline safety isolation and maintenance valve assembly shown includes an inlet pipe 1, which connects to the upstream hydrogen pipeline. It is made of 316L stainless steel seamless pipe with a nominal diameter of DN50, a wall thickness of 3.5mm, and a design pressure of 1.6MPa, capable of withstanding the corrosion and high-pressure impact of hydrogen. The inlet end of the inlet pipe 1 is equipped with a standard flange interface for easy and quick connection to the upstream pipeline.

[0027] The first branch pipe 2 and the second branch pipe 3 are fixedly connected to the intake pipe 1 via an equal-diameter tee. The tee is made of precision-cast 316L stainless steel and is fully penetrated by argon arc welding to each pipe. The weld is inspected by 100% radiographic testing to ensure connection strength and sealing. The first branch pipe 2 and the second branch pipe 3 are respectively equipped with a first shut-off valve 4. Both first shut-off valves 4 are pneumatic shut-off valves with valve bodies made of 316L stainless steel and valve seat sealing surfaces made of polytetrafluoroethylene (PTFE) or flexible graphite material, suitable for hydrogen media. The arrangement of the two first shut-off valves 4 forms a dual-valve isolation structure: the first shut-off valve 4 on the first branch pipe 2 is used to control the opening and closing of the main gas path under normal delivery conditions, and the first shut-off valve 4 on the second branch pipe 3 is used to control the opening and closing of the bypass gas path under maintenance conditions. The two are backups for each other to ensure reliable isolation under any condition.

[0028] The air inlet of the steam-water separator 5 is connected to the air outlet of the second diversion pipe 3 via a flange. The steam-water separator 5 adopts a cyclone structure with spiral guide vanes inside. It uses centrifugal force to separate the free water mist carried in the gas, with a separation efficiency of ≥95%. The shell of the steam-water separator 5 is made of 316L stainless steel plate rolled and welded with a wall thickness of 4mm. The bottom is conical to facilitate the collection of condensate. The bottom of the steam-water separator 5 is equipped with a drain port, and a manual drain ball valve is installed on the drain port for periodically discharging the separated free water.

[0029] At least two hydrogen removal units 6 are provided. The inlet and outlet ends of the two hydrogen removal units 6 are respectively fixedly connected to the same connecting unit 7. One of the connecting units 7 is connected to the gas-water separator 5, and the outlet end of the other connecting unit 7 is connected to a fixed hydrogen alarm 9. The outlet end of the fixed hydrogen alarm 9 is fixedly connected to a discharge pipe 10. The end of the discharge pipe 10 away from the fixed hydrogen alarm 9 is fixedly connected to a No. 2 tee pipe 101. One end of the No. 2 tee pipe 101 is fixedly connected to one end of the first diversion pipe 2.

[0030] Gas replenishment unit 11 is installed on the pipeline between gas-water separator 5 and hydrogen removal unit 6.

[0031] As a preferred embodiment of the present invention, the gas outlet of the gas-water separator 5 is provided with a delivery pipe 51, which is made of DN25 stainless steel. A second shut-off valve 511 and a regulating valve 512 are arranged sequentially along the airflow direction. The second shut-off valve 511 is a manual shut-off valve used to cut off the gas source when repairing or replacing downstream equipment. The regulating valve 512 is a precision needle valve with a conical valve core. It can be infinitely adjusted from 0 to 100% opening by rotating the handwheel. It is used to control the gas flow rate entering the hydrogen removal unit 6, so that the gas residence time in the honeycomb hydrogen removal plate 66 is ≥0.5 seconds, ensuring that the hydrogen is fully catalytically oxidized. The gas outlet of the delivery pipe 51 is connected to the connecting unit 7.

[0032] In this embodiment, specific references Figure 1 , Figure 2 , Figure 3 , Figure 5 and Figure 6 The hydrogen removal unit 6 consists of two units, which are connected in parallel to form a redundant structure with one unit in use and one in standby. Each hydrogen removal unit 6 includes a mounting cylinder 61, which is made of 316L stainless steel plate rolled and welded, with an inner diameter of 350mm, a height of 650mm, a wall thickness of 4mm, and a design pressure of 1.0MPa. The top of the mounting cylinder 61 is connected to an upper sealing cover 62 by flange bolts. A silicone rubber sealing gasket with a temperature resistance of 200℃ is provided between the upper sealing cover 62 and the mounting cylinder 61 to ensure reliable sealing. The bottom of the mounting cylinder 61 is connected to a lower sealing cover 63 by flange bolts. A sealing gasket is also provided between the lower sealing cover 63 and the mounting cylinder 61 to facilitate bottom drainage and maintenance.

[0033] An input pipe 611 and an output pipe 612, which communicate with the interior of the mounting cylinder 61, are fixedly installed on the outer wall of the mounting cylinder 61. The input pipe 611 is located in the lower middle part of the mounting cylinder 61, between the grid support plate 65 and the filter screen 67, and is used to introduce the gas to be treated into the mounting cylinder 61. The output pipe 612 is located in the upper part of the mounting cylinder 61, above the honeycomb hydrogen removal plate 66, and is used to lead the treated gas out of the mounting cylinder 61. The input pipe 611 and the output pipe 612 are made of DN25 stainless steel pipes and are welded to the shell of the mounting cylinder 61 with a full penetration weld structure. The weld is inspected by dye penetrant testing.

[0034] The installation cylinder 61 is provided with two annular support plates 64, which are welded and fixed to the inner wall of the installation cylinder 61. The two annular support plates 64 are arranged vertically. The upper annular support plate 64 is used to place the grid support plate 65, and the lower annular support plate 64 is used to place the filter screen 67.

[0035] The grid support plate 65 is made of 316L stainless steel mesh with a thickness of 3mm, an opening rate of 60%, and a hole diameter of 8mm. A 2mm gap is left between the edge of the mesh plate and the annular support plate 64 for easy placement and removal. The grid support plate 65 is placed on the annular support plate 64 above to support the honeycomb hydrogen removal plate 66 above, while ensuring that the gas can pass through evenly.

[0036] The honeycomb hydrogen removal plate 66 has a multi-layer structure. In this embodiment, three layers of honeycomb hydrogen removal plates 66 are provided, each layer is 50mm thick, and the total thickness is 150mm. The three layers of honeycomb hydrogen removal plates 66 are stacked on the grid support plate 65 in sequence. A 20mm flow guide gap is provided between two adjacent honeycomb hydrogen removal plates 66 so that the gas can be redistributed before entering the next layer, avoiding short-circuiting of the gas flow and improving the catalytic efficiency.

[0037] The honeycomb hydrogen removal plate 66 uses a Fe-Cr-Al metal honeycomb substrate with a pore density of 300 mesh, a wall thickness of 0.05 mm, a porosity ≥85%, and a specific surface area ≥800 m² / m³. A porous γ-Al₂O₃ whisker layer with a thickness of 10–20 μm and a specific surface area ≥150 m² / g is loaded onto the substrate surface using a vacuum impregnation process, providing a highly dispersed support for the noble metal catalyst. A Pt-Pd dual noble metal catalyst is loaded onto the whisker layer surface using a vacuum impregnation-high-temperature calcination process, with a total noble metal loading of 0.5 wt% and a Pt to Pd mass ratio of 3:1. Noble metal nanoparticles are uniformly dispersed on the surface of the γ-Al₂O₃ whisker layer, with a particle size controlled at 2–5 nm to maximize the exposure of active sites. This catalyst can react hydrogen and oxygen in a flameless catalytic oxidation reaction to generate water vapor at room temperature, with a hydrogen removal efficiency ≥99.5% and an ignition temperature as low as room temperature, requiring no additional heating equipment.

[0038] The filter screen 67 is made of 316L stainless steel sintered mesh with a filtration accuracy of 50μm and a thickness of 1.5mm. It is placed on the lower annular support plate 64. The filter screen 67 is located below the honeycomb hydrogen removal plate 66 and above the inlet pipe 611. It is used to intercept catalyst powder, rust and other solid impurities carried in the water generated by the catalytic reaction, and to prevent impurities from clogging the downstream pipeline or affecting the sealing performance of the drain valve 681.

[0039] A drain pipe 68 is provided at the bottom of the lower sealing cover 63. The drain pipe 68 is made of DN15 stainless steel and is welded and fixed at the lowest point of the lower sealing cover 63. A drain valve 681 is provided on the drain pipe 68. The drain valve 681 is an automatic timed drain valve with a built-in electromagnetic drive mechanism and is electrically connected to the control unit. It automatically opens once every 2 hours for 5 seconds each time to drain the condensate collected at the bottom of the installation cylinder 61 to a designated container. The drain valve 681 is also equipped with a manual operation handle for easy on-site manual intervention.

[0040] In this embodiment, specific references Figure 1 and Figure 6 There are two connection units 7, which are used for connecting the gas inlet end and the gas outlet end of the hydrogen removal unit 6, respectively.

[0041] Each connection unit 7 includes two connecting pipes 71, and a third shut-off valve 72 is fixedly installed on each of the two connecting pipes 71. A first-way tee pipe 73 is fixedly connected between the two third shut-off valves 72. The connecting pipes 71 are made of DN25 stainless steel pipes, and the third shut-off valves 72 are pneumatic shut-off valves with 316L valve bodies. They are connected to the connecting pipes 71 through compression fittings for easy disassembly and maintenance.

[0042] The connection unit 7 on the intake side: the output end of its No. 1 three-way pipe 73 is fixedly connected to the delivery pipe 51 of the steam-water separator 5, and the two connection pipes 71 are fixedly connected to the input pipes 611 of the two hydrogen removal units 6 respectively. By controlling the opening and closing state of the two third shut-off valves 72, the two hydrogen removal units 6 can be independently switched on and off.

[0043] The connection unit 7 on the gas outlet side: its No. 1 three-way pipe 73 is fixedly connected to the exhaust pipe 8. The exhaust pipe 8 is made of DN25 stainless steel pipe. The gas outlet end of the exhaust pipe 8 is fixedly connected to the gas inlet end of the fixed hydrogen alarm 9. The two connecting pipes 71 are fixedly connected to the output pipes 612 of the two hydrogen removal units 6 respectively.

[0044] When one of the two hydrogen removal units 6 is operating as the primary unit, the control unit opens the third shut-off valve 72 corresponding to that unit and simultaneously closes the third shut-off valve 72 of the backup unit. When the primary unit fails or the honeycomb hydrogen removal plate 66 malfunctions, the control unit automatically closes the third shut-off valve 72 corresponding to the primary unit and opens the third shut-off valve 72 corresponding to the backup unit, achieving seamless switching without shutting down the system.

[0045] In this embodiment, specific references Figure 1 and Figure 4 The gas replenishment unit 11 includes a gas storage tank 111, a hydrogen delivery pipe 112, a pulse solenoid valve 113, and an injection pipe 114. The gas storage tank 111 has a volume of 8L, a design pressure of 1.0MPa, and an operating pressure of 0.5~0.8MPa. The tank body is made of 316L stainless steel. A pressure gauge and safety valve (opening pressure 0.9MPa) are installed on the top, and a drain valve is installed at the bottom. The gas inlet of the gas storage tank 111 is equipped with a two-stage pressure reducing valve, which can be connected to an external nitrogen cylinder or instrument air system. The working medium is high-purity nitrogen (purity ≥99.99%) or dry compressed air (dew point ≤-40℃). The gas storage tank 111 integrates molecular sieve desiccant (capacity 200g) to ensure that the gas replenishment medium is dry and clean, and to prevent moisture from entering the pipeline and affecting the catalyst activity.

[0046] The outlet of the gas storage tank 111 is connected to the inlet of the pulse solenoid valve 113 via the hydrogen supply pipe 112. The hydrogen supply pipe 112 is made of 6mm stainless steel and has compression fittings at both ends. The pulse solenoid valve 113 is an explosion-proof two-position two-way direct-acting solenoid valve with a valve body made of 316L, an interface size of 1 / 2″NPT, a working pressure of 0.1~1.0MPa, a response time of ≤20ms, an explosion-proof rating of ExdIICT4, and is suitable for hydrogen environments. The solenoid valve coil is powered by 24VDC and has a power of 8W.

[0047] The outlet of the pulse solenoid valve 113 is fixedly connected to the injection pipe 114. The injection pipe 114 is made of 6mm stainless steel pipe, and its length is determined according to the site layout. Its end extends into the conveying pipe 51 on the side away from the steam-water separator 5. That is, the outlet of the injection pipe 114 is located inside the conveying pipe 51 between the regulating valve 512 and the connecting unit 7, and the outlet direction is towards the connecting unit 7 (i.e., the airflow direction).

[0048] The end of the injection pipe 114 is equipped with a turbulence nozzle. The turbulence nozzle adopts a converging-expanding (Laval tube) structure with a throat diameter of 2 mm and an outlet diameter of 5 mm. It can convert the potential energy of high-pressure gas into the kinetic energy of high-speed jet. The nozzle axis forms an angle of 25° to 45° with the pipeline axis (preferably 35° in this embodiment). The nozzle outlet faces the airflow direction. When the high-pressure gas passes through the nozzle, a jet is formed at the nozzle outlet, generating strong shock waves and vortices, which effectively disturb the gas flow in the pipeline and flush out the residual hydrogen in dead corners.

[0049] In this embodiment, specific references Figure 1 The fixed hydrogen alarm 9 has its inlet end fixedly connected to the exhaust pipe 8. The fixed hydrogen alarm 9 uses a catalytic combustion hydrogen sensor with a range of 0–1000 ppm, a resolution of 1 ppm, and a response time ≤3 seconds. It also has a built-in audible and visual alarm. A column is fixedly connected to the side wall of the fixed hydrogen alarm 9, and a mounting base is provided at the bottom of the column, allowing the alarm to be fixed in a convenient location next to the equipment.

[0050] The outlet end of the fixed hydrogen alarm 9 is fixedly connected to a discharge pipe 10, which is made of DN25 stainless steel. The end of the discharge pipe 10 away from the fixed hydrogen alarm 9 is fixedly connected to a No. 2 tee pipe 101. One end of the No. 2 tee pipe 101 is fixedly connected to one end of the first diversion pipe 2, forming a gas circulation loop. When the treated gas passes the test of the fixed hydrogen alarm 9, it can flow back to the upstream pipeline through the discharge pipe 10, the No. 2 tee pipe 101, and the first diversion pipe 2, realizing gas recycling and avoiding direct emission that would waste resources.

[0051] When the safety isolation and maintenance valve assembly for hydrogen pipelines is in operation, and maintenance of downstream equipment is required, the operator issues a maintenance command through the control unit, and the control unit automatically performs the following operations: Shutting down the main gas path: The control unit outputs a shut-off signal to the first shut-off valve 4 on the first branch pipe 2. The valve closes slowly (closing time 5-8 seconds) to avoid pressure surges that could impact the pipeline.

[0052] Open the bypass gas path: The control unit outputs an open signal to the first shut-off valve 4 on the second split pipe 3, so that the hydrogen gas remaining in the downstream pipe section of the first shut-off valve 4 enters the gas-water separator 5 through the second split pipe 3. At this time, the first shut-off valve 4 on the first split pipe 2 and the first shut-off valve 4 on the second split pipe 3 form a double isolation, the upstream gas source is reliably cut off, and the downstream pipe section to be repaired is completely isolated from the upstream gas source, ensuring the safety of the repair operation.

[0053] The residual hydrogen enters the steam-water separator 5 through the second diversion pipe 3. Inside the steam-water separator 5, the gas enters the cyclone chamber tangentially. Under the action of centrifugal force, the free water mist carried in the gas is thrown against the inner wall of the chamber and collects at the bottom. It is periodically discharged through the drain port. The hydrogen gas after removing the free water enters the conveying pipe 51 from the gas outlet at the top of the steam-water separator 5.

[0054] The control unit activates the gas replenishment unit 11 and controls the pulse solenoid valve 113 to operate according to a preset timing sequence. The specific control parameters are: the pulse solenoid valve 113 opens once every 45 seconds, each opening lasting 0.4 seconds. When the pulse solenoid valve 113 opens, the 0.6MPa high-pressure nitrogen gas stored in the gas storage tank 111 is injected at high speed into the delivery pipe 51 through the hydrogen delivery pipe 112, the pulse solenoid valve 113, and the injection pipe 114. Because the turbulence nozzle at the end of the injection pipe 114 adopts a converging-expanding structure, the high-pressure gas exits the nozzle... A jet is formed at the inlet, generating strong shock waves and eddies. The shock waves generated by the high-speed jet propagate along the pipeline, flushing out residual hydrogen in dead zones formed by bends, diameter changes, valves, and other structures, allowing it to enter the mainstream gas. At the same time, the turbulent airflow creates turbulence in the pipeline, ensuring that the hydrogen is fully mixed with the trace amounts of oxygen (or subsequently introduced compressed air) in the pipeline, preventing excessively high local hydrogen concentrations. In addition, the pulsed disturbance breaks the laminar flow state of the gas in the pipeline, preventing hydrogen from accumulating in the upper part of the pipeline due to density differences.

[0055] After being uniformly mixed by pulse disturbance, the gas enters the connection unit 7 through the regulating valve 512. The regulating valve 512 controls the gas flow rate so that the residence time of the gas in the honeycomb hydrogen removal plate 66 is ≥0.5 seconds, ensuring that the hydrogen and the catalyst are in full contact.

[0056] According to the preset primary / standby configuration, the control unit opens the third shut-off valve 72 corresponding to the primary hydrogen removal unit 6 and closes the third shut-off valve 72 corresponding to the standby hydrogen removal unit 6. The gas enters the mounting cylinder 61 of the primary hydrogen removal unit 6 through the No. 1 three-way pipe 73, the connecting pipe 71, and the input pipe 611.

[0057] After the gas enters the installation cylinder 61, it first reaches the area where the input pipe 611 is located (between the grid support plate 65 and the filter screen 67), and then passes upward through the filter screen 67 and the grid support plate 65 to enter the honeycomb hydrogen removal plate 66 area. The filter screen 67 intercepts trace solid impurities that may be carried in the gas, protecting the honeycomb hydrogen removal plate 66 from being blocked.

[0058] When the gas flows through the three-layer honeycomb hydrogen removal plate 66, the following catalytic reaction occurs: Step 1: Adsorption and Activation Hydrogen molecules (H2) and oxygen molecules (O2) diffuse to the surface of Pt-Pd noble metal nanoparticles. Pt and Pd, with their moderate chemical adsorption strength, dissociate HH bonds and O=O bonds respectively, forming active adsorbed hydrogen atoms (H) and adsorbed oxygen atoms (O), thus completing the activation process before the reaction.

[0059] Step 2: Rapid Surface Reaction Adsorbed H and O undergo a low-energy-barrier reaction on the catalyst surface, first forming the intermediate hydroxyl group (OH), and finally stabilizing to form adsorbed water molecules (H2O). This reaction process requires no external energy input, can proceed rapidly at room temperature, and is entirely flameless, thus eliminating the risk of combustion and explosion from a mechanistic perspective.

[0060] Overall reaction equation: 2H₂ + O₂ → 2H₂O + heat Step 3: Desorption and Thermal Diffusion Adsorbed water molecules (H2O) desorb from the catalyst surface and are discharged with the main gas flow. The heat released by the reaction is rapidly conducted to the entire catalytic unit through the highly thermally conductive Fe-Cr-Al metal honeycomb matrix and evenly dispersed in the gas flow, avoiding the formation of hot spots due to local temperature rise. This ensures that the catalyst surface temperature is always below 200℃, which is far below the auto-ignition point of hydrogen (585℃), thus achieving intrinsic safety.

[0061] As the water vapor generated by the reaction flows upward with the airflow, its temperature gradually decreases, and it condenses into liquid water. The liquid water flows downward under the action of gravity, and after being filtered by the filter screen 67 to remove any catalyst dust it may be carrying, it collects at the bottom of the mounting cylinder 61. The collected water is automatically discharged at regular intervals through the drain pipe 68 and the drain valve 681. The treated gas enters the fixed hydrogen alarm 9 through the output pipe 612 at the top of the mounting cylinder 61, the connecting unit 7, and the exhaust pipe 8.

[0062] The fixed hydrogen alarm 9 monitors the hydrogen concentration in the treated gas in real time. When the concentration remains below 50 ppm for 30 seconds, the fixed hydrogen alarm 9 outputs a compliance signal to the control unit. The control unit then illuminates the maintenance indicator light, allowing operators to perform maintenance on downstream equipment.

[0063] During the hydrogen removal operation, if the main hydrogen removal unit 6 is not operating properly, the third shut-off valve 72 corresponding to the main hydrogen removal unit 6 is closed, and the third shut-off valve 72 corresponding to the backup hydrogen removal unit 6 is opened at the same time. The airflow is switched to the backup hydrogen removal unit 6 to continue hydrogen removal. The entire switching process is completed quickly, the hydrogen removal operation is uninterrupted, and the maintenance preparation work is carried out continuously.

[0064] All standard parts used in this application can be purchased from the market. The specific connection methods of each part adopt conventional methods such as bolts, rivets, and welding that are mature in the prior art. The machinery, parts and equipment adopt conventional models in the prior art and are also general components, which are common knowledge in this field.

[0065] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A safety isolation and maintenance valve assembly for hydrogen pipelines, comprising an inlet pipe (1) for connecting to an upstream hydrogen pipeline, characterized in that, Also includes: The first branch pipe (2) and the second branch pipe (3) are fixedly connected to the air intake pipe (1) through a tee. The first branch pipe (2) and the second branch pipe (3) are respectively equipped with a first shut-off valve (4). The air inlet of the steam-water separator (5) is connected to the outlet of the second diverter pipe (3); At least two hydrogen removal units (6) are provided. The inlet and outlet ends of the two hydrogen removal units (6) are respectively fixedly connected to the same connecting unit (7). One of the connecting units (7) is connected to the gas-water separator (5). The outlet end of the other connecting unit (7) is connected to a fixed hydrogen alarm (9). The outlet end of the fixed hydrogen alarm (9) is fixedly connected to a discharge pipe (10). The end of the discharge pipe (10) away from the fixed hydrogen alarm (9) is fixedly connected to a No. 2 three-way pipe (101). One end of the No. 2 three-way pipe (101) is fixedly connected to one end of the first diversion pipe (2). Gas replenishment unit (11) is installed on the pipeline between the gas-water separator (5) and the hydrogen removal unit (6).

2. The hydrogen pipeline safety isolation and maintenance valve assembly equipment according to claim 1, characterized in that: The gas outlet of the gas-water separator (5) is provided with a delivery pipe (51), and a second shut-off valve (511) and a regulating valve (512) are sequentially provided on the delivery pipe (51). The gas outlet of the delivery pipe (51) is connected to the connecting unit (7).

3. The hydrogen pipeline safety isolation and maintenance valve assembly equipment according to claim 1, characterized in that, The hydrogen removal unit (6) consists of two units, which are arranged in parallel. The hydrogen removal unit (6) includes an installation cylinder (61), an upper sealing cover (62) located at the top of the installation cylinder (61), a lower sealing cover (63) located at the bottom of the installation cylinder (61), and a grid support plate (65), a honeycomb hydrogen removal plate (66), and a filter screen (67) arranged sequentially from top to bottom inside the installation cylinder (61). The outer wall of the mounting cylinder (61) is fixedly fitted with an input pipe (611) and an output pipe (612) that communicate with the inside of the mounting cylinder (61), and the input pipe (611) and the output pipe (612) are arranged one below the other.

4. The hydrogen pipeline safety isolation and maintenance valve assembly equipment according to claim 3, characterized in that: The bottom of the lower sealing cover (63) is provided with a drain pipe (68), and a drain valve (681) is provided on the drain pipe (68).

5. The hydrogen pipeline safety isolation and maintenance valve assembly equipment according to claim 3, characterized in that: The mounting cylinder (61) is also provided with an annular support plate (64). There are two annular support plates (64). The grid support plate (65) and the filter screen (67) are respectively placed on the annular support plate (64). The grid support plate (65) is located above the filter screen (67). The input pipe (611) is located between the grid support plate (65) and the filter screen (67). The output pipe (612) is located above the honeycomb hydrogen removal plate (66). The honeycomb hydrogen removal plate (66) has a multi-layer structure.

6. The hydrogen pipeline safety isolation and maintenance valve assembly equipment according to claim 1, characterized in that: The connection unit (7) includes a connection pipe (71), there are two connection pipes (71), and a third shut-off valve (72) is fixedly installed on each of the two connection pipes (71). A first three-way pipe (73) is fixedly connected between the two third shut-off valves (72). There are two connection units (7). The output end of the No. 1 three-way pipe (73) of one of the connection units (7) is fixedly connected to the delivery pipe (51), and the other is fixedly connected to the exhaust pipe (8). The exhaust pipe (8) is fixedly connected to the air inlet of the fixed hydrogen alarm (9). The two connecting pipes (71) of the two connecting units (7) are fixedly connected to the input pipe (611) and output pipe (612) of the two hydrogen removal units (6), respectively.

7. The hydrogen pipeline safety isolation and maintenance valve assembly equipment according to claim 1, characterized in that: The gas replenishment unit (11) includes a gas storage tank (111), a hydrogen supply pipe (112), a pulse solenoid valve (113), and an injection pipe (114). The gas outlet of the gas storage tank (111) is connected to the gas inlet of the pulse solenoid valve (113) through the hydrogen supply pipe (112). The gas outlet of the pulse solenoid valve (113) is fixedly connected to the injection pipe (114). The end of the injection pipe (114) extends into the delivery pipe (51) on the side away from the gas-water separator (5).

8. The hydrogen pipeline safety isolation and maintenance valve assembly equipment according to claim 7, characterized in that: The pulse solenoid valve (113) of the air replenishment unit (11) is an explosion-proof two-position two-way direct-acting solenoid valve. The end of the injection pipe (114) is provided with a turbulence nozzle. The turbulence nozzle adopts an expansion structure. The nozzle axis is at an angle of 25° to 45° with the pipeline axis, and the nozzle outlet faces the airflow direction.

9. The hydrogen pipeline safety isolation and maintenance valve assembly equipment according to claim 1, characterized in that: The side wall of the fixed hydrogen alarm (9) is fixedly connected to a column.

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