Soundproof safety valve explosion testing device

Abstract

The utility model belongs to hydrogen energy safety technology, concretely relates to a sound insulation type safety valve explosion testing device, including pressure release valve test board, its characterized in be: still include sound insulation storehouse, set up mounting platform in sound insulation storehouse, mounting platform fixed connection pressure release valve test board, and pressure release valve test board is used for connecting the input of measured valve body, and mounting platform side sets up n level expansion cavity, and n level expansion cavity is connected in turn, and the cross section area is gradually larger, wherein the head of first level expansion cavity sets up the connecting port that is connected with the output of measured valve body, and the top of sound insulation storehouse sets up the muffler, and the muffler one end communicates the nth level expansion cavity, and the muffler other end sets up the exhaust outlet that projects sound insulation storehouse.

Description

Technical Field

[0001] This utility model belongs to hydrogen energy safety technology, specifically relating to a soundproof safety valve explosion testing device. Background Technology

[0002] Safety valves, or pressure relief valves, are used to release pressure from high-pressure, sealed environments created during system failures. To ensure safety performance, the safety valves must undergo pressure relief capacity testing after leaving the factory. Existing safety valve tests typically simulate operating conditions such as those of transformers, testing their ability to discharge inert gases under high-pressure conditions. The testing equipment, such as CN201190820Y or CN210829978U, includes a sealed storage tank. The tank is used to create a high-pressure environment, and a fixture for installing the safety valve is located at the top output end of the tank. During testing, the safety valve is installed on the tank, and the tank releases pressure to test the performance of the safety valve.

[0003] In the hydrogen production process, there is a lack of dedicated testing structures and environments for hydrogen, a flammable and explosive gas. However, the country attaches great importance to production safety and requires the implementation of safety valve explosion tests to conduct fault simulation tests on safety valves used for pressure relief in hydrogen production.

[0004] The safety valve explosion test refers to the test of a safety valve's ability to expel hydrogen gas at a specific pressure from a closed environment within a specific time, causing an explosion. Safety valves that exceed the specified time are considered unqualified products.

[0005] Since hydrogen can explode when it comes into contact with air, the existing detection device that exposes the safety valve poses a great safety hazard. In addition, the noise level at 2 meters from the safety valve outlet reaches 135dB(A), which does not meet the sound level limit standard, so it cannot be put into practical use. Utility Model Content

[0006] To address the problem that existing safety valve pressure release testing equipment exposes the safety valve during testing, making it unsuitable for explosion testing, this utility model provides a soundproof safety valve explosion testing device.

[0007] The purpose of this utility model is achieved in the following manner: a soundproof safety valve explosion testing device, including a pressure relief valve test bench 1 and a soundproof chamber 2, wherein an installation platform 21 is provided inside the soundproof chamber 2, the installation platform 21 is fixedly connected to the pressure relief valve test bench 1, the pressure relief valve test bench 1 is used to connect to the input end of the valve body under test, an n-stage expansion chamber is provided on the side of the installation platform 21, the n-stage expansion chambers are connected end to end, and the cross-sectional area increases sequentially, wherein the head end of the first-stage expansion chamber is provided with a connection port 31 connected to the output end of the valve body under test, a silencer 5 is provided on the top of the soundproof chamber 2, one end of the silencer 5 is connected to the n-stage expansion chamber, and the other end of the silencer 5 is provided with an exhaust outlet 51 extending out of the soundproof chamber 2.

[0008] Furthermore, the gap between the outer wall of the installation platform 21 and the inner wall of the soundproof chamber 2 forms a U-shaped channel 4, which serves as the second-stage expansion cavity. One side of the U-shaped channel 4 is fixedly connected to one end of the guide tube 3, and the other end of the guide tube 3 is a connection port 31, which serves as the first-stage expansion cavity. The other side of the U-shaped channel 4 connects to the inner cavity of the soundproof chamber 2 above the installation platform 21, which serves as the third-stage expansion cavity, and the third-stage expansion cavity connects to the silencer 5.

[0009] Furthermore, an inert gas inlet pipe 41 is provided on the wall of the soundproof chamber 2 on the side of the U-shaped channel 4, which is connected to the outside of the soundproof chamber 2. A sealing cover 42 is fixed on the outer wall of the soundproof chamber 2 and is sleeved on the outside of the inert gas inlet pipe 41. The sealing cover 42 is an openable and closable structure.

[0010] Furthermore, the muffler 5 includes a channel structure formed by the plate structure and the inner wall of the soundproof chamber 2. A sound-absorbing plate 52 extending along the channel direction is fixedly connected inside the channel structure. A hydrogen sensor 53 is provided on the exhaust outlet 51 of the muffler 5.

[0011] Furthermore, the bottom of the soundproof compartment 2 is fixedly connected to the forklift bracket 6.

[0012] Furthermore, the total volume of the n expansion cavities is V. e V e satisfy in, The total volume of the expansion chamber is the theoretical minimum, S is the volume safety factor (S≥1), V0 is the initial volume of the container, P0 is the initial absolute pressure, P2 is atmospheric pressure, γ is the hydrogen adiabatic index, and T is the total volume of the expansion chamber. f T0 represents the flame temperature during the hydrogen explosion, and T0 represents the initial temperature.

[0013] Furthermore, the connection port 31 is the point with the smallest cross-sectional area in the n-stage expansion cavity, and the cross-sectional area of ​​the connection port 31 is... , satisfy in, To minimize the required cross-sectional area for drainage, This is the explosion reduction factor. The total mass of hydrogen gas released; The standard time for emitting hydrogen; Let be the critical mass flux of hydrogen, where: in, γ is the gas pressure at the output end when the hydrogen tail section of the valve body under test is emptied; γ is the hydrogen adiabatic index; R is the universal gas constant; T0 is the initial temperature; and M is the gas molar mass.

[0014] Compared to existing technologies, this invention uses a soundproof chamber to cover the safety valve and testing equipment, and sets up multiple expansion chambers to reduce pressure and noise, making it suitable for safety valve explosion testing environments. Attached Figure Description

[0015] Figure 1 This is a front sectional view of a soundproof safety valve explosion testing device; Figure 2 This is a front sectional view of a soundproof safety valve explosion testing device after the safety valve is installed. Figure 3 This is a top sectional view of a soundproof safety valve explosion testing device; Figure 4 yes Figure 1 The sectional view at point aa.

[0016] The components include: pressure relief valve test bench 1, soundproof chamber 2, installation platform 21, flange 22, guide pipe 3, connection port 31, U-shaped channel 4, inert gas inlet pipe 41, sealing cover 42, silencer 5, exhaust outlet 51, sound-absorbing plate 52, hydrogen sensor 53, forklift bracket 6, observation window 7, and safety valve 8. Detailed Implementation

[0017] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0018] In this utility model, unless otherwise explicitly specified and limited, the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" 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 this utility model and 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 this utility model.

[0019] As attached Figure 1-4As shown, a soundproof safety valve explosion testing device includes a pressure relief valve test bench 1, which is prior art (refer to CN201190820Y or CN210829978U). The test bench 1 includes a sealed storage tank, inside which a high-pressure environment is set. A fixing device for installing a safety valve is provided at the output end of the top of the tank. During testing, the safety valve is installed on the tank, and the tank releases pressure to test the performance of the safety valve. The tank is equipped with pressure and temperature measuring devices to detect the state during pressure release. It also includes a soundproof chamber 2. The soundproof chamber 2 is... The soundproof chamber 2 is a cylindrical structure made of explosion-proof material. An installation platform 21 is set inside the soundproof chamber 2. The installation platform 21 is fixedly connected to the pressure relief valve test bench 1. The pressure relief valve test bench 1 is used to connect to the input end of the valve body under test. The installation platform 21 has n-stage expansion chambers on its side. The n-stage expansion chambers are connected end to end and the cross-sectional area increases sequentially. The first stage expansion chamber has a connection port 31 at its head end that is connected to the output end of the valve body under test. The soundproof chamber 2 has a silencer 5 at its top. One end of the silencer 5 is connected to the n-stage expansion chamber, and the other end of the silencer 5 has an exhaust outlet 51 that extends out of the soundproof chamber 2.

[0020] After high-pressure hydrogen enters the first and smallest chamber, the space suddenly expands, and the pressure and flow rate generated by the explosion will decrease significantly for the first time. Then it enters the next larger chamber, where the pressure and speed are reduced again. Through this step-by-step and controllable expansion, the pressure, speed and concentration of the gas flow have been reduced to a safe level, and its explosive energy is greatly weakened, rather than a destructive explosion.

[0021] Preferably, the effective cross-sectional area of ​​each expansion cavity satisfies "A(n+1) / A(n)≥ k (k takes 1.5~3.0), that is, the effective cross-sectional area of ​​each expansion cavity is greater than k times the effective cross-sectional area of ​​the previous expansion cavity, to ensure the smooth expansion of the explosion airflow.

[0022] Furthermore, the installation platform 21 is a U-shaped plate, which extends to the inner wall of the soundproof chamber 2 on the front and rear sides and forms a fixed structure. A cylindrical structure is set inside the U-shaped plate for setting the pressure relief valve test bench 1. The gap between the outer wall of the left and right sides of the installation platform 21 and the inner wall of the soundproof chamber 2 forms a U-shaped channel 4, which serves as the second-stage expansion cavity. One side of the U-shaped channel 4 is fixedly connected to one end of the guide tube 3, and the other end of the guide tube 3 is a connection port 31, which is used to cooperate with the output end of the safety valve 8. The guide tube 3 serves as the first-stage expansion cavity. The other side of the U-shaped channel 4 connects to the inner cavity of the soundproof chamber 2 above the installation platform 21. The inner cavity of the soundproof chamber 2 above the installation platform 21 serves as the third-stage expansion cavity, which connects to the silencer 5.

[0023] This scheme allows for the rational arrangement of three expansion chambers within a regular cubic space, enabling the explosion pressure to be diluted sequentially.

[0024] Furthermore, an inert gas inlet pipe 41 is installed on the wall of the soundproof chamber 2 on the side of the U-shaped channel 4, which is connected to the outside of the soundproof chamber 2. A sealing cover 42 is fixed on the outer wall of the soundproof chamber 2 and fitted onto the outside of the inert gas inlet pipe 41. The sealing cover 42 is an openable and closable structure. The openable and closable structure can be a threaded cover or a hinged cover. Regardless of the type, a sealing strip and a locking structure are provided between the sealing cover 42 and the soundproof chamber 2 to prevent gas from overflowing from the inert gas inlet pipe 41 during an explosion.

[0025] The inert gas inlet pipe 41 is used to connect to the nitrogen flushing hydrogen equipment. After a single test, the hydrogen in the soundproof chamber 2 is flushed immediately, and after the standard is met, subsequent tests are carried out to ensure the safety of the test bench.

[0026] Furthermore, the silencer 5 includes a channel structure formed by the plate structure and the inner wall of the soundproof chamber 2. The silencer 5 can be one of resistive / reactive / composite silencing structures. Preferably, a silencing plate 52 extending along the channel direction is fixedly connected inside the channel structure to reduce noise from the high-speed exhaust airflow. Preferably, the A-weighted noise reduction at 1m of the equipment is ≥50 dB. A hydrogen sensor 53 is installed on the exhaust outlet 51 of the silencer 5 to detect whether the hydrogen content in the exhaust gas meets the standard. In actual use, the chamber door is allowed to be opened / the next test is allowed only if the hydrogen volume fraction at the outlet is ≤0.4%.

[0027] Furthermore, a channel steel is fixedly connected to each of the bottom sides of the soundproof compartment 2, and the two channel steels are arranged in parallel to serve as forklift brackets 6.

[0028] Furthermore, an observation window 7 is provided on the side of the soundproof chamber 2. The observation window 7 is made of explosion-proof glass and is used to observe the condition inside the chamber.

[0029] Preferably, the soundproof chamber 2 is composed of two interlocking shell parts, with flanges 22 respectively provided at the interlocking points of the two shell parts, and the two flanges are connected and fixed by connectors.

[0030] Preferably, since the environment containing hydrogen is generally defined as hazardous zone 2, the explosion-proof function needs to be reasonably designed, such as setting flame arrestor elements / cellular flow limiting before and after the expansion cavity or silencer section; setting explosion relief guide and safety boundary in the exhaust direction; the soundproof chamber 2 and the installation platform 21 are made of carbon steel or alloy steel, such as Q345R, 16MnDR, SA-516 Gr.70, etc., with a thickness requirement of 20~50mm.

[0031] Because the safety valve is enclosed in a nearly enclosed space, in order to ensure that the safety valve 8 can release pressure normally without obstruction, the expansion chamber needs to have a sufficiently large cross-sectional area to allow for normal airflow, and the expansion chamber also needs to have a sufficiently large total volume to accommodate the expansion caused by the explosion. A design that is too small may interfere with the normal release of hydrogen, but a design that is too large will also lead to an increase in manufacturing and transportation costs. Therefore, the following section will discuss how to obtain the minimum and recommended values ​​of these two parameters based on specific operating conditions.

[0032] First, obtain the required parameters using the following method: S1. Prepare pressure relief valve test bench 1. Determine V0, i.e., the original "old space" of the system, based on the storage space of pressure relief valve test bench 1. Determine the initial pressure P0 before pressure relief according to the performance requirements of the valve body under test. The value of P0 is generally between 1 and 4 MPa, as well as the required pressure relief time. , The value is typically between 1 and 3 ms; S2. Based on the required value P0, fill the pressure relief valve test bench 1 with hydrogen gas until the pressure inside the test bench 1 reaches P0, and determine the volume V of hydrogen gas filled. H2 The total mass of hydrogen is obtained based on the hydrogen density. ; In S2, the pressure relief valve test bench 1 can measure the proportion of hydrogen introduced, thereby obtaining the volume V of hydrogen in the pressure relief valve test bench 1 after the filling process is completed. H2 ,calculate At that time, the hydrogen density in test bench 1 was measured using the pressure relief valve. Perform calculations, specifically. Where 0.089 is the density of hydrogen at room temperature and pressure, in units of... , This is the normal pressure value.

[0033] S3. Install and fix the valve body under test on the pressure relief valve test bench 1, perform a pressure relief operation, and detect the temperature T at the output end of the valve body under test during the pressure relief process. f And the pressure at the output end, taking the pressure at the tail end during the discharge process as... ; The purpose of taking the pressure at the tail end of the emission process is to understand that in the later stages of emission, the pressure drops significantly, the emission capacity weakens, and the critical mass flux is reached. As the value decreases, a larger cross-sectional area is required for successful discharge; therefore, the value of the tail section is taken. If measurement is inconvenient, 10% P0 can be taken; S4. Determine the atmospheric pressure of the test scenario. Values ​​and room temperature T0 value; S5. Calculate the theoretical minimum total volume of the expansion cavity based on the parameters obtained from S1-S4. The size of the soundproof chamber 2 and the minimum cross-sectional area required for venting are designed accordingly. The size of the guide tube 3 and the connection port 31 are designed accordingly.

[0034] Specifically, the total volume of the n expansion cavities is V. e V e satisfy in, The total volume of the expansion chamber is the theoretical minimum. S is the volume safety factor, which is generally taken as 2. When S is 1, it is the limit value. When S is 2 or greater, it means that sufficient redundancy design is provided. V0 is the initial volume of the container. The initial volume of the container V0 can be calculated only for the volume of the pressure relief valve test bench 1, or the volume of the safety valve 8 can be included. P0 is the initial absolute pressure, that is, the pressure inside the tank of the pressure relief valve test bench 1. P2 is the atmospheric pressure. γ is the hydrogen adiabatic index, which is taken as 1.41. T f T is the flame temperature during the hydrogen explosion. f It can be measured, or 2000K can be chosen. The explosion temperature of hydrogen is generally between 2000K and 3000K. The reason for choosing 2000K is to be the "earliest time point" peak temperature under a given compression ratio and adiabatic index. As the mixture continues to expand, the temperature rises further to 2500–3000K, but at this time the pressure has dropped significantly to a low pressure, so the impact on the volume requirement is relatively small. T0 is the initial temperature.

[0035] The derivation of this formula: Calculate the isentropic expansion volume using the Poisson equation. The Poisson equation itself applies to systems with no heat exchange (Q=0) and no friction or dissipation. However, in this depressurization condition, we only use the Poisson stage to describe the depressurization start-up from 0 to 0.3 ms. Within this window, the reaction has not yet fully ignited, and the internal structure remains approximately adiabatic and reversible. The paper "Dryer & Shepherd 2009 (Comb. Sci. Tech.)" indicates that the induction period of H2–O2 at 2 MPa and 300 K is ~0.4 ms; the Poisson stage modeling interval is ≤0.3 ms; after which the exothermic stage begins, which is uniformly considered by the equation (temperature rise).

[0036] Although the hydrogen explosion produces water vapor during this process, the heat release > temperature increase > volume expansion; the phase change produces a mixture of H2O(g) and N2 / O2, resulting in a slight decrease in the total molar volume, but the temperature rise is the dominant factor. CFD-CHEMKIN comparison: the volume difference between the phase change and non-phase change phases is <5%.

[0037] The expansion factor required to reduce the pressure to atmospheric pressure when the gas undergoes only mechanical expansion without releasing heat.

[0038] Calculate the volume correction value after the temperature rise following the explosion. : The combustion of hydrogen raises the temperature from T0 to the flame temperature Tf, and the volume continues to increase.

[0039] Actual design volume It is the expansion of gas from its initial state to T f , The "new" volume required in this state is equivalent to the "extra" buffer space that must be provided.

[0040] The safety factor S is referenced in NFPA 68-2023 8.5.3 (expansion chambers or explosion-proof cavities should be ≥1.5–2.5 times the calculated volume), with a minimum value of 1, but preferably 1.5–2.5, while also covering manufacturing tolerances, flow resistance and ambient temperature fluctuations.

[0041] Substituting into the above formula, we get Specific calculation formula.

[0042] Specifically, the connection port 31 is the point with the smallest cross-sectional area in the n-stage expansion cavity, and the cross-sectional area of ​​the connection port (31) is... , satisfy in, To determine the minimum required cross-sectional area for drainage; The explosion reduction factor is generally taken as 1.3. The explosion reduction factor kexo = 1.1-1.3 (NFPA 68 recommendation) is introduced to form the final design formula. That is, the designer only needs to input the operating parameters to calculate the "must ≥ how much" pipe cross-section, and then leave a safety margin of 10-30% on this basis. The total mass of hydrogen gas released; For the standard time to release hydrogen, safety valve 8 generally requires a venting time of 1~3ms; According to the EN 14994 criterion for explosive venting, under the condition of a hydrogen-oxygen cloud of 0.2 m³ / 1.6 MPa, the arrival time of the first peak of the shock wave is 2–3 ms, so it is required to complete the depressurization within this period.

[0043] The critical mass flux of hydrogen refers to the physical limiting flow rate (kg m⁻² s⁻¹) of a hydrogen jet at a specific pressure and temperature, where: in, The pressure at the output end can be measured when the hydrogen tail section of the valve body under test is purged. Alternatively, 10% P0 can be taken; γ is the adiabatic index of hydrogen, taken as 1.41; R is the universal gas constant, taken as 8.314 J / (mol·K); T0 is the initial temperature, which can be taken as 298K. M is the molar mass of the gas, which can be taken as 2 g / mol.

[0044] Only when both of the above formulas are true can the device guarantee operation at a specific time under the most unfavorable operating conditions. Internal pressure The hydrogen gas is safely reduced to atmospheric pressure and meets all the limits of GB 50177-2021 for residual pressure, temperature rise and noise. When the silent test device is working, the noise at one meter outside its chamber is ≤85dB(A), which meets the equivalent sound level limit requirements for 8 hours of working time specified in the "Hygienic Standard for Industrial Enterprise Design" (GBZ1-2002).

[0045] The above description is only a preferred embodiment of the present utility model. It should be noted that those skilled in the art can make several changes and improvements without departing from the overall concept of the present utility model, and these should also be considered within the protection scope of the present utility model.

Claims

1. A soundproof safety valve explosion testing device, comprising a pressure relief valve test bench (1), characterized in that: It also includes a soundproof chamber (2), in which an installation platform (21) is set up. The installation platform (21) is fixedly connected to a pressure relief valve test bench (1). The pressure relief valve test bench (1) is used to connect to the input end of the valve body under test. The installation platform (21) is provided with an n-stage expansion chamber on the side. The n-stage expansion chambers are connected end to end and their cross-sectional areas increase sequentially. The first-stage expansion chamber has a connection port (31) at the head end that is connected to the output end of the valve body under test. A silencer (5) is set on the top of the soundproof chamber (2). One end of the silencer (5) is connected to the n-stage expansion chamber, and the other end of the silencer (5) is provided with an exhaust outlet (51) extending out of the soundproof chamber (2).

2. The soundproof safety valve explosion testing device as described in claim 1, characterized in that: The gap between the outer wall of the installation platform (21) and the inner wall of the soundproof chamber (2) forms a U-shaped channel (4). The U-shaped channel (4) serves as the second-stage expansion cavity. One side of the U-shaped channel (4) is fixedly connected to one end of the guide tube (3), and the other end of the guide tube (3) is the connection port (31). The guide tube (3) serves as the first-stage expansion cavity. The other side of the U-shaped channel (4) is connected to the inner cavity of the soundproof chamber (2) above the installation platform (21). The inner cavity of the soundproof chamber (2) above the installation platform (21) serves as the third-stage expansion cavity. The third-stage expansion cavity is connected to the silencer (5).

3. The soundproof safety valve explosion testing device as described in claim 2, characterized in that: An inert gas inlet pipe (41) connected to the outside of the soundproof chamber (2) on the side of the U-shaped channel (4) is provided on the chamber wall. A sealing cover (42) sleeved on the outside of the inert gas inlet pipe (41) is fixed on the outer wall of the soundproof chamber (2). The sealing cover (42) is an openable structure.

4. The soundproof safety valve explosion testing device as described in claim 1, characterized in that: The muffler (5) includes a channel structure formed by the plate structure and the inner wall of the sound insulation chamber (2). A muffler plate (52) extending along the channel direction is fixedly connected inside the channel structure. A hydrogen sensor (53) is installed on the exhaust outlet (51) of the muffler (5).

5. The soundproof safety valve explosion testing device as described in claim 1, characterized in that: The bottom of the soundproof compartment (2) is fixedly connected to the forklift bracket (6).

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