A blocking device and method for flammable gas pipeline backfire

Abstract

This invention relates to the field of hydrogen and oxygen production technology via water electrolysis, and discloses a device and method for preventing backfire in combustible gas pipelines. The device includes a flame arrester tank, with a gas-water separation plate above the inner cavity of the tank and a gas distribution plate below the inner cavity. An inlet pipe is located below the gas-water separation plate, with its lower end penetrating the gas distribution plate and extending to the bottom of the tank, and its upper end extending outwards from the tank. An explosion-proof end cap is sealed at the top of the flame arrester tank, with its upper end connected to a main gas outlet pipe, which is connected to both the main gas outlet pipe and an exhaust port. A water inlet and a drain pipe are connected to the bottom of the flame arrester tank. This invention uses ordinary water as the fire extinguishing medium, employing multi-stage fire arresting for coordinated protection, ensuring the safety of upstream equipment and pipelines. The device boasts high fire arresting efficiency, good operational stability, strong safety and reliability, long service life, low overall cost, and convenient daily maintenance, demonstrating excellent comprehensive practicality.

Description

Technical Field

[0001] This invention relates to the field of hydrogen and oxygen production technology through water electrolysis, and in particular to a device and method for preventing backfire in a combustible gas pipeline. Background Technology

[0002] With the rapid development of industrial manufacturing, metal processing, and new energy fields, hydrogen-oxygen mixtures produced by water electrolysis are widely used as clean and efficient industrial fuels and gas sources in many production scenarios such as flame cutting, welding heating, and glass tube processing. The combustible gas transmission pipeline network is the core hub connecting the electrolysis gas production equipment and the gas-consuming end; its operational safety directly determines the stability and reliability of the entire production system.

[0003] Backfire is the most common and extremely dangerous safety accident during the transportation and use of combustible gases. When the combustion rate at the gas-consuming end exceeds the gas output flow rate, pipeline pressure fluctuates, or operation is improper, the combustion flame can propagate backward along the gas pipeline. If not effectively blocked, the flame will spread to the upstream electrolysis gas-generating equipment, causing gas deflagration, equipment rupture, or even a factory fire, seriously threatening the lives of on-site personnel and the safety of company property. Therefore, a reliable backfire prevention device is an essential core safety protection device in the electrolysis water gasification and transportation system.

[0004] Currently, the mainstream combustible gas flame arresters used in the industry are dry-type structures, commonly employing corrugated plate, metal mesh, filled / gravel, and parallel plate / perforated plate designs. All are based on the flame quenching principle, utilizing the tiny slits and perforations formed by the flame-arresting element to rapidly absorb flame heat through the wall's heat dissipation effect, extinguishing the flame as it passes through the channel. While these devices are compact and space-saving, and have some applicability in dry, clean conventional gas transportation scenarios, they suffer from numerous problems when used in highly alkaline and high-humidity conditions such as water electrolysis for hydrogen and oxygen production. These problems include short lifespan, high cost, poor reliability, high maintenance costs, and complex maintenance operations. The hydrogen-oxygen mixture produced by water electrolysis has extremely high humidity and easily carries alkaline electrolyte droplets and electrolytic impurities. After being passed through a dry flame arrester for a long time, the alkaline medium will cause corrosion and damage to the metal corrugated plate, metal mesh, perforated plate and other flame arrestor cores. At the same time, the impurities carried by water vapor are prone to deposit and scale in the slits and gravel pores, causing blockage of the flame arrestor channel. This will not only greatly increase the flow resistance of the pipeline and reduce the gas transmission efficiency, but also directly weaken the flame arrestor performance, resulting in a significant reduction in the overall service life of the device.

[0005] Therefore, those skilled in the art urgently need to develop a device and method for preventing backfire in combustible gas pipelines. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art by proposing a device and method for preventing backfire in combustible gas pipelines.

[0007] Based on one objective of the present invention, the following technical solution is proposed: a device for preventing backfire in a combustible gas pipeline, comprising a flame arrester tank, a gas-water separation plate provided above the inner cavity of the flame arrester tank, a gas distribution plate provided below the inner cavity of the flame arrester tank, an air inlet pipe provided below the gas-water separation plate, the lower end of the air inlet pipe vertically penetrating the gas distribution plate and extending to the bottom of the flame arrester tank, and the upper end of the air inlet pipe horizontally extending outward from the flame arrester tank; The top of the flame arrester tank is sealed with an explosion-proof end cap. The upper end of the explosion-proof end cap is connected to the main gas outlet pipe. The top end of the main gas outlet pipe is connected to an emergency pressure relief valve. The main gas outlet pipe branches into two pipes, which are respectively connected to the gas outlet pipe and the exhaust port. Both the air outlet and air inlet pipes are equipped with check valves. The bottom of the flame arrester tank is connected to a water inlet and a drain outlet. On / off valves are installed on the air outlet, exhaust outlet, water inlet, and drain outlet pipes.

[0008] Preferably, the gas-water separation plate is inclined, the gas distribution plate is horizontal, and the outer edges of both the gas-water separation plate and the gas distribution plate are sealed to the inner wall of the flame arrester tank.

[0009] Preferably, the explosion-proof end cap includes an upwardly arched upper arc plate, which is sealed and fixed to the top opening of the flame arrester tank, and the main gas outlet pipe vertically passes through the upper arc plate to form a sealed connection.

[0010] Preferably, the lower side of the upper arc plate is connected to a downwardly arched lower arc plate, a circular air hole is opened at the bottom center of the lower arc plate, and four semi-circular air holes are symmetrically distributed around the lower arc plate to achieve uniform and dispersed airflow.

[0011] Preferably, a small arc-shaped plate with an upward arch is arranged coaxially between the upper arc-shaped plate and the lower arc-shaped plate. The small arc-shaped plate is fixedly connected to the lower arc-shaped plate. The small arc-shaped plate has four semi-circular small air holes symmetrically opened around its circumference. The multi-layer arc-shaped plates work together to extend the airflow path and help buffer the shock wave.

[0012] Preferably, a level gauge is connected to the outer wall of the flame arrester tank, and a support base plate is fixedly connected to the outer bottom of the flame arrester tank.

[0013] Based on another objective of this invention, a method for preventing backfire in a combustible gas pipeline is proposed, comprising the following steps: S1. Connect the inlet pipe to the hydrogen and oxygen gas source, connect the outlet pipe to the combustible gas delivery pipeline at the rear end, connect the water inlet to the water supply pipeline, and connect the drain pipe to the drain pipeline; open the water inlet shut-off valve and inject water into the flame arrester tank so that the water level is higher than the gas distribution plate and the bottom of the inlet pipe to form a continuous water seal layer, and complete the equipment pre-preparation. S2. The hydrogen-oxygen mixed combustible gas is introduced into the water at the bottom of the tank through the inlet pipe. The gas rises and passes through the water layer, hitting the gas distribution plate. Large bubbles are broken into tiny bubbles. The bubbles continue to rise and escape from the water surface. The gas flows upward through the gas-water separation plate. The water vapor carried by the gas condenses on the surface of the plate. The dried combustible gas is transported to the rear pipeline through the outlet pipe. S3. When backfire occurs in the back-end pipeline and the flame is transmitted in reverse to the outlet pipeline port, the check valve on the outlet pipeline closes quickly to achieve the first backfire prevention. S4. If the flame breaks through the check valve and enters the upper space of the flame arrester tank and flashover occurs, the instantaneously increased pressure inside the tank will trigger the emergency pressure relief valve to open, quickly releasing the shock wave pressure. The water seal in the lower part of the tank will block the flame from spreading downwards, forming a second fire barrier to prevent the flame from spreading towards the air intake pipe. S5. The check valve on the intake pipeline forms the third protective barrier. Relying on the one-way isolation of the check valve, the water seal flame isolation, and the emergency pressure relief of overpressure, multiple protections reliably block backfire, preventing backfire from being transmitted back to the front-end hydrogen-oxygen generating equipment and protecting the safety of the entire gas production system and transmission pipeline.

[0014] Compared with the prior art, the beneficial effects of the present invention are: 1. Multi-level fire-resistant and coordinated protection with high reliability in preventing backfire: Constructing multiple progressive fire barriers, combined with an overpressure emergency relief mechanism, can curb the spread of backfire from multiple dimensions such as physical isolation, media flame isolation, and pressure relief, effectively blocking the reverse propagation of flames and shock waves, and ensuring the safety of front-end equipment and pipelines.

[0015] 2. The explosion-proof buffer design is well-developed and the structural safety performance is outstanding. The multi-layer arc-shaped buffer head structure extends the propagation path of the shock wave and weakens the peak impact level step by step. Combined with the rapid pressure relief mechanism, it can directionally release the flashover pressure, effectively reduce the damage of backfire flashover to the tank structure, and improve the overall explosion-proof and impact-resistant performance of the device.

[0016] 3. Low operation and maintenance costs and wide range of application scenarios. It uses clean water as the core flame arrestor, which is easy to obtain and has no special consumable requirements. The device has a compact and intuitive structure, and is easy to maintain and operate. It can be adapted to a variety of combustible gas transportation scenarios and is compatible with gas production and transportation systems of different scales. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a front structural cross-sectional view of the present invention; Figure 3 This is a side view of the structural cross-section of the present invention; Figure 4 This is a top view of the structure of the present invention; Figure 5 This is a top perspective view of the explosion-proof end cap described in this invention; Figure 6 This is a front perspective view of the explosion-proof end cap described in this invention; Figure 7 for Figure 5 A cross-sectional view along the BB direction.

[0018] In the diagram: 1-Emergency pressure relief valve; 2-Flame arrester tank; 3-Level gauge; 4-Inlet pipe; 5-Outlet pipe; 6-Water inlet; 7-Drain outlet; 8-Gas distribution plate; 9-Gas-water separator plate; 10-Explosion-proof end cap; 11-Exhaust pipe outlet; 12-Base plate; 13-Upper arc plate; 14-Lower arc plate. Detailed Implementation

[0019] The present invention will now be clearly described with reference to the accompanying drawings and specific embodiments. This description is merely illustrative and is not intended to limit the scope of the invention. Any modifications, equivalent substitutions, or improvements made by those skilled in the art based on the embodiments of the present invention without inventive effort to obtain all other embodiments should be included within the scope of protection of the present invention.

[0020] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0021] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0022] Example 1 Please see Figures 1-7 The present invention provides a device for preventing backfire in a combustible gas pipeline, comprising a vertically arranged flame arrester tank 2, a gas-water separation plate 9 above the inner cavity of the flame arrester tank 2, a gas distribution plate 8 below the inner cavity of the flame arrester tank 2, an air inlet pipe 4 below the gas-water separation plate 9, the lower end of the air inlet pipe 4 vertically downward through the gas distribution plate 8 and extending to the bottom of the flame arrester tank 2, and the upper end of the air inlet pipe 4 horizontally outward through the flame arrester tank 2 and forming a sealed fit.

[0023] The top of the flame arrester tank 2 is sealed with an explosion-proof head 10. The upper end of the explosion-proof head 10 is connected to the main gas outlet pipeline. The top end of the main gas outlet pipeline is connected to the emergency pressure relief valve 1. The main gas outlet pipeline branches into two pipelines, which are respectively connected to the gas outlet pipeline 5 and the exhaust port 11.

[0024] Check valves are installed on both the exhaust pipe 5 and the inlet pipe 4. Water inlet 6 and drain pipe 7 are connected to the bottom of the flame arrester tank 2 respectively. On / off valves are installed on the exhaust pipe 5, exhaust pipe 11, water inlet 6 and drain pipe 7.

[0025] Preferably, the gas-water separation plate 9 is inclined at an angle of 5°-15°, and the plate body is evenly distributed with ventilation micropores; the gas distribution plate 8 is horizontally arranged, and the plate body is arranged with an array of circular ventilation holes. The outer edges of both the gas-water separation plate 9 and the gas distribution plate 8 are sealed and fixedly connected to the inner wall of the flame arrester tank 2. The inclined arrangement of the gas-water separation plate allows the liquid water condensed on the plate surface to flow along the slope to the inner wall of the tank and fall back to the lower water body, avoiding water accumulation and affecting the ventilation area.

[0026] Preferably, the explosion-proof end cap 10 includes an upwardly arched upper arc plate 13, which is sealed and fixed to the top opening of the flame arrester tank 2. The main vent pipe runs vertically through the upper arc plate 13 and forms a sealed connection. The lower side of the upper arc plate 13 is connected to a downwardly arched lower arc plate 14. A circular vent hole is opened at the bottom center of the lower arc plate 14, and four semi-circular vent holes are symmetrically distributed around the lower arc plate to achieve uniform and dispersed airflow and avoid localized concentrated airflow impacting the end cap structure.

[0027] Furthermore, a small arc-shaped plate arching upwards is coaxially arranged between the upper arc-shaped plate 13 and the lower arc-shaped plate 14. The small arc-shaped plate is fixedly connected to the lower arc-shaped plate 14. The small arc-shaped plate has four semi-circular small air holes symmetrically opened around its circumference. The multi-layer arc-shaped plates work together to extend the airflow path, gradually weaken the peak value of the shock wave, and help buffer the instantaneous impact force generated by the backfire and flashover.

[0028] Preferably, a level gauge 3 is connected to the outer wall of the flame arrester tank 2. The upper and lower ends of the level gauge 3 are respectively connected to the upper air chamber and the lower water body of the tank for real-time observation of the water seal level in the tank. A support base plate 12 is fixedly connected to the outer bottom of the flame arrester tank 2 for stable installation and fixation of the tank.

[0029] Example 2 The present invention also provides a method for preventing backfire in a combustible gas pipeline, including the backfire prevention device for combustible gas pipelines in the above embodiments, and further including the following steps: S1. Connect the inlet pipe 4 to the hydrogen and oxygen gas source, the outlet pipe 5 to the combustible gas delivery pipeline at the rear end, the water inlet 6 to the water supply pipeline, and the drain pipe 7 to the drain pipeline; open the on / off valve of the water inlet 6 and inject water into the flame arrester tank 2, observe the liquid level through the level gauge 3 until the water level is higher than the upper surface of the gas distribution plate 8, forming a continuous and stable water seal layer, close the on / off valve of the water inlet 6, and complete the equipment pre-preparation.

[0030] S2. The hydrogen-oxygen mixed combustible gas is introduced into the water at the bottom of the tank through the inlet pipe 4. The gas rises and passes through the water layer, hitting the gas distribution plate 8. Large bubbles are broken into tiny bubbles. The bubbles continue to rise and escape from the water surface. The gas flows upward through the gas-water separation plate 9. The water vapor carried by the gas condenses on the surface of the plate. The dried combustible gas is transported to the rear pipeline through the outlet pipe 5.

[0031] S3. When backfire occurs in the back-end pipeline and the flame is transmitted in reverse to the port of the outlet pipeline 5, the check valve on the outlet pipeline 5 is quickly closed by the reverse airflow and pressure, physically blocking the reverse airflow channel and achieving the first backfire barrier.

[0032] S4. If the flame breaks through the check valve and enters the upper space of the flame arrester tank 2 and flashover occurs, the pressure inside the tank will rise sharply and instantaneously, triggering the emergency pressure relief valve 1 at the top to open rapidly and release the shock wave and high-temperature gas generated by the flashover in a directional manner to prevent the tank from being damaged by overpressure. At the same time, the continuous water seal layer at the bottom of the tank uses the cooling and flame-insulating effect of water to block the flame and high-temperature airflow from spreading downward, forming a second fire barrier to prevent the flame from spreading to the side of the air intake pipe 4.

[0033] S5 and the check valve on the intake pipe 4 form the third protective barrier, which can further block the reverse airflow and flame from propagating to the gas source side under extreme conditions. Through the coordinated action of the check valve's one-way blocking, water seal flame isolation cooling, and overpressure emergency pressure relief, the multiple protective structures reliably block backfire, preventing backfire from being transmitted back to the front-end hydrogen-oxygen generating equipment and protecting the operational safety of the entire gas production system and transmission pipeline.

[0034] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A device for preventing backfire in a combustible gas pipeline, characterized in that: The device includes a flame arrester tank (2), with a gas-water separation plate (9) above the inner cavity of the flame arrester tank (2), a gas distribution plate (8) below the inner cavity of the flame arrester tank (2), an air inlet pipe (4) below the gas-water separation plate (9), the lower end of the air inlet pipe (4) vertically penetrating the gas distribution plate (8) and extending to the bottom of the flame arrester tank (2), and the upper end of the air inlet pipe (4) horizontally extending outward from the flame arrester tank (2). The top of the flame arrester tank (2) is sealed with an explosion-proof head (10). The upper end of the explosion-proof head (10) is connected to the main gas outlet pipeline. The top end of the main gas outlet pipeline is connected to the emergency pressure relief valve (1). The main gas outlet pipeline branches into two pipelines, which are respectively connected to the gas outlet pipeline (5) and the exhaust port (11). Check valves are installed on the air outlet pipe (5) and the air inlet pipe (4). The bottom of the flame arrester tank (2) is connected to the water inlet (6) and the drain pipe (7). On / off valves are installed on the air outlet pipe (5), the exhaust pipe (11), the water inlet pipe (6) and the drain pipe (7).

2. The backfire prevention device for combustible gas pipelines according to claim 1, characterized in that: The gas-water separation plate (9) is inclined, the gas distribution plate (8) is horizontal, and the outer edges of the gas-water separation plate (9) and the gas distribution plate (8) are sealed to the inner wall of the flame arrester tank (2).

3. The backfire prevention device for combustible gas pipelines according to claim 1, characterized in that: The explosion-proof end cap (10) includes an upwardly arched upper arc plate (13), which is sealed and fixed at the top opening of the flame arrester tank (2). The main gas outlet pipe runs vertically through the upper arc plate (13) and forms a sealed connection.

4. The backfire prevention device for a combustible gas pipeline according to claim 3, characterized in that: The lower side of the upper arc plate (13) is connected to the lower arc plate (14) that arches downwards. A circular air hole is opened at the bottom center of the lower arc plate (14), and four semi-circular air holes are symmetrically distributed around the lower arc plate to achieve uniform airflow.

5. The backfire prevention device for a combustible gas pipeline according to claim 4, characterized in that: A small arc plate that arches upwards is arranged coaxially between the upper arc plate (13) and the lower arc plate (14). The small arc plate is fixedly connected to the lower arc plate (14). The small arc plate has four semi-circular small air holes symmetrically opened around its circumference. The multi-layer arc plates work together to extend the airflow path and help buffer the shock wave.

6. The backfire prevention device for a combustible gas pipeline according to claim 1, characterized in that: A level gauge (3) is connected to the outer wall of the flame arrester tank (2), and a support base plate (12) is fixedly connected to the outer bottom of the flame arrester tank (2).

7. A method for preventing backfire in a combustible gas pipeline, characterized in that: The method, using the backfire prevention device for combustible gas pipelines as described in any one of claims 1 to 6, further includes the following steps: S1. Connect the inlet pipe (4) to the hydrogen and oxygen gas source, connect the outlet pipe (5) to the combustible gas delivery pipeline at the rear end, connect the water inlet (6) to the water supply pipeline, and connect the drain pipe (7) to the drain pipeline; open the on / off valve of the water inlet (6) and inject water into the flame arrester tank (2) so that the water level is higher than the bottom of the gas distribution plate (8) and the inlet pipe (4) to form a continuous water seal layer and complete the equipment pre-preparation; S2. The hydrogen-oxygen mixed combustible gas is introduced into the water body at the bottom of the tank through the inlet pipe (4). The gas floats up and passes through the water layer and hits the gas distribution plate (8). The large bubbles are broken into small bubbles. The bubbles continue to float up and escape from the water surface. The gas flows upward through the gas-water separation plate (9). The water vapor carried by the gas condenses on the surface of the plate. The dried combustible gas is transported to the rear pipeline through the outlet pipe (5). S3. When backfire occurs in the back-end pipeline and the flame is transmitted in reverse to the port of the gas outlet pipeline (5), the check valve on the gas outlet pipeline (5) closes quickly to achieve the first backfire barrier. S4. If the flame breaks through the check valve and enters the upper space of the flame arrester tank (2) and flashover occurs, the instantaneously increased tank pressure triggers the emergency pressure relief valve (1) to open, quickly releasing the shock wave pressure. The water seal in the lower part of the tank blocks the flame from spreading downward, forming a second fire barrier to prevent the flame from spreading towards the air intake pipe (4). S5. The check valve on the intake pipeline (4) forms the third protective barrier. Relying on the check valve's one-way blocking, water seal flame isolation, and overpressure emergency pressure relief, multiple protections are used to reliably block backfire, prevent backfire from being transmitted back to the front-end hydrogen and oxygen generating equipment, and protect the safety of the entire gas production system and transmission pipeline.

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