A method and apparatus for selectively measuring hydrogen concentration based on acoustic technology

Abstract

The application discloses a device for selectively measuring hydrogen concentration based on acoustic technology, comprising: a measuring cavity module comprising a reference gas measuring cavity and a target gas measuring cavity; an ultrasonic transceiver module, at least two pairs of ultrasonic transducers are arranged in the reference gas measuring cavity and the target gas measuring cavity respectively; a signal generation module, connected with the ultrasonic transceiver module, outputs homologous signals with different frequencies to the ultrasonic transducers; a signal processing module, connected with the ultrasonic transceiver module, collects and processes received ultrasonic signals to obtain hydrogen concentration; part of the to-be-measured gas flows through a hydrogen adsorption module and then enters the reference gas measuring cavity, and the other part of the to-be-measured gas enters the target gas measuring cavity. The application also discloses a method corresponding to the device. The device can realize selective measurement of hydrogen and improve the measurement accuracy of hydrogen.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of hydrogen concentration measurement, and particularly relates to a method and device for selectively measuring hydrogen concentration based on acoustic technology. BACKGROUND

[0002] Hydrogen is widely used in aerospace, military, clean power generation, transportation and chemical industry as a pollution-free, efficient and clean energy and important chemical raw material. However, hydrogen is a flammable and explosive gas with high diffusivity, which can easily explode when the volume ratio in air is above 4% at normal temperature and pressure. Effective detection of hydrogen is crucial to ensure the safety of hydrogen in industrial production.

[0003] At present, the hydrogen detectors at home and abroad mainly include optical type, electrochemical type, catalytic type and semiconductor type. The optical gas sensor has high accuracy, but the price is too high and the environmental adaptability is weak, which cannot work stably for a long time in a severe polluted environment. The electrochemical and catalytic sensors generally have poor long-term stability, high power consumption and short service life. The metal oxide semiconductor type sensor has poor stability and linearity and high power consumption, which is not suitable for high accuracy environmental application.

[0004] With the development of hydrogen energy application, how to further reduce the cost of hydrogen sensor and detect the hydrogen concentration composition with low cost and high accuracy needs to be further solved.

[0005] Using acoustic technology to measure hydrogen concentration has the advantages of fast response, low cost, small power consumption, long service life, good stability and strong environmental adaptability. However, the hydrogen detection technology based on acoustics has the problems of poor hydrogen selectivity and low detection accuracy due to the interference of other gases, dust particles and temperature and humidity. For example, the Chinese patent with the application number CN201710633542.6 provides a method for determining the concentration and pressure of each gas in a plurality of gases, which can be summarized as measuring the concentration and pressure of the gas based on calibration. However, this invention does not consider the influence of dust particles and air humidity, and does not provide an effective selective measurement scheme for specific gases, especially hydrogen. The Chinese patent with the application number CN202110251272.9 provides a hydrogen measurement system and method based on ultrasonic double-frequency phase difference, which provides a solution to the problem of small hydrogen concentration detection range based on ultrasonic phase difference method, but does not provide a solution to how to improve the hydrogen measurement selectivity and exclude the interference of other gases, dust particles and temperature and humidity.

[0006] Up to now, there is still lack of effective and feasible solutions to how to exclude the interference of other gases, dust particles and temperature and humidity, and improve the hydrogen selectivity and measurement accuracy of the hydrogen measurement technology based on acoustics. SUMMARY

[0007] The application aims to provide a method and device for selectively measuring hydrogen concentration based on acoustic technology, which can selectively measure hydrogen and improve the measurement accuracy of hydrogen.

[0008] The application provides the following technical solutions:

[0009] A device for selectively measuring hydrogen concentration based on acoustic technology, comprising:

[0010] A measurement cavity module comprising a reference gas measurement cavity and a target gas measurement cavity;

[0011] An ultrasonic transceiver module comprising six pairs of ultrasonic transducers, three pairs of which are arranged at the same positions of the reference gas measurement cavity and the target gas measurement cavity: one pair is placed at the two ends of the reference gas measurement cavity and the target gas measurement cavity along the axis, and the other two pairs are placed on the outer side of the wall surface of the reference gas measurement cavity and the target gas measurement cavity in axial symmetric positions;

[0012] A hydrogen adsorption module for adsorbing hydrogen in the gas to be measured;

[0013] A signal generation module connected to the ultrasonic transceiver module for outputting homologous signals of different frequencies to the three pairs of ultrasonic transducers;

[0014] A signal processing module connected to the ultrasonic transceiver module for collecting and processing the received ultrasonic signals to obtain the hydrogen concentration;

[0015] A part of the gas to be measured flows through the hydrogen adsorption module and enters the reference gas measurement cavity, and the other part of the gas to be measured enters the target gas measurement cavity.

[0016] The ultrasonic transducers comprise three pairs of ultrasonic transducers arranged at the same positions of the reference gas measurement cavity and the target gas measurement cavity: one pair is placed at the two ends of the reference gas measurement cavity and the target gas measurement cavity along the axis, and the other two pairs are placed on the outer side of the wall surface of the reference gas measurement cavity and the target gas measurement cavity in axial symmetric positions; specifically:

[0017] The first ultrasonic transducer and the second ultrasonic transducer are placed at the two ends of the reference gas measurement cavity along the axis, and the third ultrasonic transducer and the fourth ultrasonic transducer, as well as the fifth ultrasonic transducer and the sixth ultrasonic transducer, are placed on the outer side of the wall surface of the reference gas measurement cavity in axial symmetric positions;

[0018] The seventh ultrasonic transducer and the eighth ultrasonic transducer are oppositely arranged at two ends of the target gas measuring cavity along the axis, and the ninth ultrasonic transducer and the tenth ultrasonic transducer and the eleventh ultrasonic transducer and the twelfth ultrasonic transducer are oppositely arranged on the outside of the wall surface of the target gas measuring cavity in an axisymmetric position.

[0019] The signal generation module is connected with the first ultrasonic transducer and the seventh ultrasonic transducer, and outputs a homologous signal with a frequency f1; the signal generation module is connected with the third ultrasonic transducer and the ninth ultrasonic transducer, and outputs a homologous signal with a frequency f2; the signal generation module is connected with the fifth ultrasonic transducer and the eleventh ultrasonic transducer, and outputs a homologous signal with a frequency f3.

[0020] The signal processing module is connected with the second ultrasonic transducer, the fourth ultrasonic transducer, the sixth ultrasonic transducer, the eighth ultrasonic transducer, the tenth ultrasonic transducer and the twelfth ultrasonic transducer.

[0021] The hydrogen adsorption module comprises an adsorption material container and hydrogen adsorption material, and the hydrogen adsorption material is selected from AB5 type alloy, AB2 type alloy, AB type alloy, A2B type alloy, palladium-based material, metal hydride, carbon material, coordination hydride, gas hydrate, porous carbon material, metal organic framework compound, microporous organic polymer or zeolite.

[0022] Preferably, the device comprises a dust and moisture removal module comprising a first dust and moisture removal device and a second dust and moisture removal device, the first dust and moisture removal device is connected with the gas inlet of the reference gas measuring cavity, and the second dust and moisture removal device is connected with the gas inlet of the target gas measuring cavity; the part of the to-be-measured gas sequentially flows through the hydrogen adsorption module and the first dust and moisture removal device into the reference gas measuring cavity.

[0023] The dust and moisture removal module provided by the application avoids the interference of dust particles and gas humidity by using a particulate filter screen and a water removal agent to remove dust and moisture from the to-be-measured gas.

[0024] The first dust and moisture removal device and the second dust and moisture removal device are structurally identical and comprise a dust particle filter screen and a water removal agent.

[0025] Preferably, the device comprises a temperature measuring module arranged inside the reference gas measuring cavity and the target gas measuring cavity. The real-time temperature of the gas is measured by the temperature measuring module to avoid interference caused by temperature changes.

[0026] The temperature measuring module comprises a first temperature sensor and a second temperature sensor, and the first temperature sensor and the second temperature sensor are arranged inside the reference gas measuring cavity and the target gas measuring cavity, respectively.

[0027] In the present application, the reference gas measuring cavity and the target gas measuring cavity are provided with air inlets and air outlets at two ends, and the two cavities have consistent structure and size.

[0028] The signal generation module comprises a signal generator and a signal connection line, and is connected with the ultrasonic transceiver module; the signal processing module comprises a signal processor and a signal connection line, and is connected with the ultrasonic transceiver module, the temperature measuring module and the signal generation module.

[0029] The present application also provides a method for selectively measuring hydrogen concentration based on acoustic technology by using the above device, which comprises the following steps:

[0030] (1) a part of the gas to be measured flows through the hydrogen adsorption module and the first dust and moisture remover in sequence and then enters the reference gas measuring cavity to form a reference measurement channel;

[0031] (2) another part of the gas to be measured flows through the second dust and moisture remover and then enters the target gas measuring cavity to form a target measurement channel;

[0032] (3) the signal generation module sends signals with frequency f1 to the first ultrasonic transducer and the seventh ultrasonic transducer, so that the first ultrasonic transducer and the seventh ultrasonic transducer respectively send ultrasonic waves to the second ultrasonic transducer and the eighth ultrasonic transducer, and the signal processing module obtains the sound wave attenuation coefficient a1 between the first ultrasonic transducer and the second ultrasonic transducer, the ultrasonic wave phase difference between the second ultrasonic transducer in the reference measurement channel and the eighth ultrasonic transducer in the target measurement channel

[0033] (4) the signal generation module sends signals with frequency f2 to the third ultrasonic transducer and the ninth ultrasonic transducer, so that the third ultrasonic transducer and the ninth ultrasonic transducer respectively send ultrasonic waves to the fourth ultrasonic transducer and the tenth ultrasonic transducer, and the signal processing module obtains the sound wave attenuation coefficient a2 between the third ultrasonic transducer and the fourth ultrasonic transducer, the ultrasonic wave phase difference between the fourth ultrasonic transducer in the reference measurement channel and the tenth ultrasonic transducer in the target measurement channel

[0034] (5) the signal generation module sends signals with frequency f3 to the fifth ultrasonic transducer and the eleventh ultrasonic transducer, so that the fifth ultrasonic transducer and the eleventh ultrasonic transducer respectively send ultrasonic waves to the sixth ultrasonic transducer and the twelfth ultrasonic transducer, and the signal processing module obtains the sound wave attenuation coefficient a3 between the fifth ultrasonic transducer and the sixth ultrasonic transducer, the ultrasonic wave phase difference between the sixth ultrasonic transducer in the reference measurement channel and the twelfth ultrasonic transducer in the target measurement channel

[0035] (6) The signal processing module collects the sound wave attenuation coefficients a1, a2, a3 of the reference measurement channel, and solves the volume fractions u1, u2, u3 of the interference gas components in the reference gas measurement cavity by simultaneously solving the sound attenuation equation set;

[0036] (7) The signal processing module collects the ultrasonic phase difference of the reference measurement channel and the target measurement channel Solves the volume fraction u0' of the measured hydrogen in the target gas measurement cavity and the volume fractions u1', u2', u3' of the interference gas components by simultaneously solving the sound velocity equation set.

[0037] Preferably, the ranges of f1, f2 and f3 are 1000 Hz to 100 MHz.

[0038] The present application utilizes the principle that the sound velocity and the sound attenuation coefficient are different in different gas media, calculates the component difference of different gases by measuring the difference of the sound velocity and the sound attenuation coefficient between different gases, uses a material with hydrogen selective adsorption function to adsorb and remove hydrogen in the target gas, and then places the original target gas and the reference gas after hydrogen selective adsorption in a cavity with the same structure: first, in the reference measurement channel, the sound attenuation coefficients of the reference gas under different frequency ultrasonic waves are measured, the sound attenuation equation set is solved, and the concentrations of multiple interference gases are solved; second, in the target measurement channel, multiple sets of sound velocity phase differences of the same source ultrasonic waves in the two cavities are measured, the sound velocity phase difference equation set is solved, the concentration information of the multiple interference gases obtained in the reference measurement channel is combined, and the concentration of the measured hydrogen in the target gas is calculated, thereby realizing selective measurement of hydrogen in the mixed gas and improving the measurement accuracy.

[0039] On the basis of realizing hydrogen selective measurement, the dust removal and dehumidification module in the present application can further avoid the interference of dust particles and gas humidity, and the temperature measurement module in the present application can monitor the real-time temperature of the measured gas to avoid interference caused by temperature changes, thereby further improving the measurement accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 The structure diagram of a device for selectively measuring the concentration of hydrogen based on acoustic technology is schematically shown.

[0041] Figure 1Each of the number legends in the figure represents: 1 - first ultrasonic transducer; 2 - second ultrasonic transducer; 3 - third ultrasonic transducer; 4 - fourth ultrasonic transducer; 5 - fifth ultrasonic transducer; 6 - sixth ultrasonic transducer; 7 - seventh ultrasonic transducer; 8 - eighth ultrasonic transducer; 9 - ninth ultrasonic transducer; 10 - tenth ultrasonic transducer; 11 - eleventh ultrasonic transducer; 12 - twelfth ultrasonic transducer; 13 - reference gas measuring cavity; 14 - target gas measuring cavity; 15 - first temperature sensor; 16 - second temperature sensor; 17 - first dust and moisture remover; 18 - second dust and moisture remover; 19 - hydrogen adsorption module; 20 - signal processing module; 21 - signal generating module;

[0042] Figure 2 Actual measurement signal result graph for measuring low concentration hydrogen leaked into air in the embodiment of the present application. DETAILED DESCRIPTION

[0043] The substantial features and advancement of the present application are further illustrated by the embodiments of the accompanying drawings, but the present application is by no means limited to the embodiments, i.e. the present application is not limited to the embodiments.

[0044] In the description of the embodiments, the positions or structural relationships indicated by the terms "side", "left end", "right end", "both ends", "interior", "symmetry", "mounted on", "connected", "injected" are based on the positions or structural relationships shown in the drawings, and are only for the purpose of describing the present application, and do not mean that the present application must have such positions or structural relationships, and the positions, sizes, shapes and structural relationships of the components in the drawings do not completely reflect the actual positions, sizes, shapes and structural relationships of the components, and are only schematic structural diagrams, and therefore cannot be understood as limitations on the present application.

[0045] Similarly, in the embodiments, the terms "first", "second", etc. are only used to describe the features, and cannot be understood as the number of features of the invention or the priority of the examples of the invention. The terms "in this preferred embodiment", "embodiment", "for example", etc. are used to describe an optional but not necessary specific embodiment, and are not the invention itself.

[0046] The first embodiment of the application provides a device for selectively measuring hydrogen concentration based on acoustic technology, which comprises a first ultrasonic transducer 1, a second ultrasonic transducer 2, a third ultrasonic transducer 3, a fourth ultrasonic transducer 4, a fifth ultrasonic transducer 5, a sixth ultrasonic transducer 6, a seventh ultrasonic transducer 7, an eighth ultrasonic transducer 8, a ninth ultrasonic transducer 9, a tenth ultrasonic transducer 10, an eleventh ultrasonic transducer 11, a twelfth ultrasonic transducer 12, a reference gas measuring cavity 13, a target gas measuring cavity 14, a first temperature sensor 15, a second temperature sensor 16, a first dust and moisture remover 17, a second dust and moisture remover 18, a hydrogen adsorption module 19, a signal processing module 20 and a signal generating module 21.

[0047] The reference gas measuring cavity 13 and the target gas measuring cavity 14 form a measuring cavity module, and gas inlets and outlets are arranged at both ends of the cavity, and the structures and sizes of the two cavities are consistent.

[0048] The first ultrasonic transducer 1, the second ultrasonic transducer 2, the third ultrasonic transducer 3, the fourth ultrasonic transducer 4, the fifth ultrasonic transducer 5, the sixth ultrasonic transducer 6, the seventh ultrasonic transducer 7, the eighth ultrasonic transducer 8, the ninth ultrasonic transducer 9, the tenth ultrasonic transducer 10, the eleventh ultrasonic transducer 11 and the twelfth ultrasonic transducer 12 form six pairs of ultrasonic transducers, and the six pairs of ultrasonic transducers are installed on the reference gas measuring cavity 13 and the target gas measuring cavity 14.

[0049] The first dust and moisture remover 17 and the second dust and moisture remover 18 form a dust and moisture removal module, the first dust and moisture remover 17 is connected with the gas inlet of the reference gas measuring cavity 13, and the second dust and moisture remover 18 is connected with the gas inlet of the target gas measuring cavity 14.

[0050] The hydrogen adsorption module 19 comprises an adsorption material container and hydrogen adsorption material, and is connected with the first dust and moisture remover 17.

[0051] The first temperature sensor 15 and the second temperature sensor 16 form a temperature measuring module, and the first temperature sensor 15 and the second temperature sensor 16 are arranged in the reference gas measuring cavity 13 and the target gas measuring cavity 14, respectively.

[0052] The signal generating module 21 comprises a signal generator and a signal connection line, and is connected with the first ultrasonic transducer 1, the third ultrasonic transducer 3, the fifth ultrasonic transducer 5, the seventh ultrasonic transducer 7, the ninth ultrasonic transducer 9 and the eleventh ultrasonic transducer 11.

[0053] The signal processing module 20 comprises a signal processor and signal connection lines, which are connected with the second ultrasonic transducer 2, the fourth ultrasonic transducer 4, the sixth ultrasonic transducer 6, the eighth ultrasonic transducer 8, the tenth ultrasonic transducer 10, the twelfth ultrasonic transducer 12, the first temperature sensor 15, the second temperature sensor 16, and the signal generating module 21.

[0054] In the preferred embodiment, the reference gas measuring cavity 13 and the target gas measuring cavity 14 are columnar bodies.

[0055] In the preferred embodiment, the to-be-measured gas flows through the hydrogen adsorption module 19 and the first dust and moisture remover 17 in sequence, enters the reference gas measuring cavity 13 from the gas inlet of the cavity, and forms a reference measurement channel.

[0056] In the preferred embodiment, the to-be-measured gas flows through the second dust and moisture remover 18, enters the target gas measuring cavity 14 from the gas inlet of the cavity, and forms a target measurement channel.

[0057] In the preferred embodiment, the first ultrasonic transducer 1 and the second ultrasonic transducer 2 are oppositely arranged along the axis at the two ends of the reference gas measuring cavity 13; the seventh ultrasonic transducer 7 and the eighth ultrasonic transducer 8 are oppositely arranged along the axis at the two ends of the target gas measuring cavity 14; the third ultrasonic transducer 3 and the fourth ultrasonic transducer 4, and the fifth ultrasonic transducer 5 and the sixth ultrasonic transducer 6 are oppositely arranged in axial symmetry on the wall surface of the reference gas measuring cavity 13; and the ninth ultrasonic transducer 9 and the tenth ultrasonic transducer 10, and the eleventh ultrasonic transducer 11 and the twelfth ultrasonic transducer 12 are oppositely arranged in axial symmetry on the wall surface of the target gas measuring cavity 14.

[0058] In the preferred embodiment, the signal generating module 21 is connected with the first ultrasonic transducer 1 and the seventh ultrasonic transducer 7, and outputs a homologous signal with a frequency f1; the signal generating module 21 is connected with the third ultrasonic transducer 3 and the ninth ultrasonic transducer 9, and outputs a homologous signal with a frequency f2; and the signal generating module 21 is connected with the fifth ultrasonic transducer 5 and the eleventh ultrasonic transducer 11, and outputs a homologous signal with a frequency f3.

[0059] In the preferred embodiment, the signal processing module 20 is connected with the second ultrasonic transducer 2, the fourth ultrasonic transducer 4, the sixth ultrasonic transducer 6, the eighth ultrasonic transducer 8, the tenth ultrasonic transducer 10, and the twelfth ultrasonic transducer 12, and collects and processes signals.

[0060] In the preferred embodiment, the first dust and moisture remover 17 and the second dust and moisture remover 18 have the same specific structure, and comprise a dust particle filter screen and a moisture removing agent.

[0061] The second embodiment of the present application proposes a method for selectively measuring hydrogen concentration based on acoustic technology, the steps comprising:

[0062] (1) The to-be-measured gas is injected into the reference gas measurement cavity 13 after the hydrogen in the to-be-measured gas is selectively adsorbed and removed by the hydrogen adsorption module 19, and the particulate matter and water vapor in the to-be-measured gas are filtered and removed by the first dust and moisture remover 17;

[0063] (2) The to-be-measured gas is injected into the target gas measurement cavity 14 after the particulate matter and water vapor in the to-be-measured gas are filtered and removed by the second dust and moisture remover 18;

[0064] (3) The signal generation module 21 sends a signal with frequency f1 to the first ultrasonic transducer 1 and the seventh ultrasonic transducer 7, so that the first ultrasonic transducer 1 and the seventh ultrasonic transducer 7 respectively send ultrasonic waves to the second ultrasonic transducer 2 and the eighth ultrasonic transducer 8, and the signal processing module 20 obtains the acoustic attenuation coefficient a1 between the first ultrasonic transducer 1 and the second ultrasonic transducer 2, the ultrasonic phase difference between the second ultrasonic transducer 2 in the reference measurement channel and the eighth ultrasonic transducer 8 in the target measurement channel

[0065] (4) The signal generation module 21 sends a signal with frequency f2 to the third ultrasonic transducer 3 and the ninth ultrasonic transducer 9, so that the third ultrasonic transducer 3 and the ninth ultrasonic transducer 9 respectively send ultrasonic waves to the fourth ultrasonic transducer 4 and the tenth ultrasonic transducer 10, and the signal processing module 20 obtains the acoustic attenuation coefficient a2 between the third ultrasonic transducer 3 and the fourth ultrasonic transducer 4, the ultrasonic phase difference between the fourth ultrasonic transducer 4 in the reference measurement channel and the tenth ultrasonic transducer 10 in the target measurement channel

[0066] (5) The signal generation module 21 sends a signal with frequency f3 to the fifth ultrasonic transducer 5 and the eleventh ultrasonic transducer 11, so that the fifth ultrasonic transducer 5 and the eleventh ultrasonic transducer 11 respectively send ultrasonic waves to the sixth ultrasonic transducer 6 and the twelfth ultrasonic transducer 12, and the signal processing module 20 obtains the acoustic attenuation coefficient a3 between the fifth ultrasonic transducer 5 and the sixth ultrasonic transducer 6, the ultrasonic phase difference between the sixth ultrasonic transducer 6 in the reference measurement channel and the twelfth ultrasonic transducer 12 in the target measurement channel

[0067] (6) The first temperature sensor 15 and the second temperature sensor 16 respectively transmit the gas temperature information in the reference gas measurement cavity 13 and the target gas measurement cavity 14 to the signal processing module 20, and the signal processing module 20 obtains the temperature T, T' of the gas in the reference measurement channel and the target measurement channel;

[0068] (7) The volume fractions u1, u2, and u3 of the interfering gas components in the reference gas measurement chamber 13 are solved according to the equation group (1);

[0069]

[0070] Wherein, the subscript i represents the i-th interfering gas, c is the gas sound velocity, M is the relative molecular mass of the gas, R is the universal gas constant, f is the sound wave frequency, ω is the sound wave angular frequency, and γ = C p / C v is the specific heat ratio, C p is the constant pressure specific heat of gas molecules, C v is the constant volume specific heat of gas molecules, μ' is the gas viscosity coefficient, k is the thermal conductivity, p0 and ρ0 are the gas static pressure and density respectively, C v0 with C v∞ are the specific heat of gas at constant volume under extremely high frequency excitation and without excitation, respectively, and τ is the gas relaxation time. When calculating the gas sound velocity, the temperature T of the reference measurement channel is used for calculation, which plays a certain role in temperature compensation.

[0071] Solve equation group (1) to calculate the volume fractions u1, u2, and u3 of each interfering gas component in the reference gas;

[0072] (8) The volume fraction u0' of the hydrogen gas to be measured in the target gas measurement chamber 14 and the volume fractions u1', u2', and u3' of each interfering gas component are solved according to equation group (2);

[0073]

[0074] Wherein, L is the length of the reference gas measurement cavity 13 and the target gas measurement cavity 14, and D is the diameter of the reference gas measurement cavity 13 and the target gas measurement cavity 14. When calculating the gas sound velocity, the temperature T' of the target measurement channel is used for calculation, which has a certain effect on temperature compensation.

[0075] Solve equation group (2) to calculate the hydrogen gas integral fraction u0' to be measured in the target gas.

[0076] In this preferred embodiment, the frequencies f1, f2, and f3 range from 1000 Hz to 100 MHz.

[0077] Figure 2 This is a diagram showing the actual measurement signal results of measuring low-concentration hydrogen leaking into the air in this embodiment. Figure 2 It can be seen that the ultrasonic phase and amplitude attenuation signals of different target gases measured using the present invention vary significantly, and the measurement signals of trace hydrogen leaks of different concentrations differ significantly, which can effectively detect hydrogen with a concentration as low as 100 ppm in mixed gases.

[0078] The above merely provides the preferred embodiment of the application, and the protection scope of the application is not limited thereto. Any modification or replacement easily conceived by those skilled in the art within the technical scope disclosed by the application should be covered within the protection scope of the application. Therefore, the protection scope of the application should be subject to the protection scope of the claims.

Claims

1. A method for selectively measuring hydrogen concentration based on acoustic technology, characterized by, The method comprises the following steps: (1) a part of the to-be-tested gas sequentially flows through the hydrogen adsorption module and the first dust and moisture remover, and then enters the reference gas measuring cavity, forming a reference measuring channel; (2) another part of the to-be-tested gas flows through the second dust and moisture remover and enters the target gas measuring cavity, forming a target measuring channel; (3) the signal generating module sends a signal with frequency f1 to the first ultrasonic transducer and the seventh ultrasonic transducer, so that the first ultrasonic transducer and the seventh ultrasonic transducer send ultrasonic waves to the second ultrasonic transducer and the eighth ultrasonic transducer respectively, and the signal processing module obtains the ultrasonic wave phase difference between the second ultrasonic transducer in the reference measurement channel and the eighth ultrasonic transducer in the target measurement channel (4) the signal generating module sends signals with frequency f2 to the third ultrasonic transducer and the ninth ultrasonic transducer, so that the third ultrasonic transducer and the ninth ultrasonic transducer send ultrasonic waves to the fourth ultrasonic transducer and the tenth ultrasonic transducer respectively, and the signal processing module obtains the ultrasonic wave phase difference between the fourth ultrasonic transducer in the reference measurement channel and the tenth ultrasonic transducer in the target measurement channel (5) the signal generating module sends signals with frequency f3 to the fifth and eleventh ultrasonic transducers, so that the fifth and eleventh ultrasonic transducers send ultrasonic waves to the sixth and twelfth ultrasonic transducers respectively, and the signal processing module obtains the acoustic wave attenuation coefficient a3 between the fifth and sixth ultrasonic transducers, and the ultrasonic wave phase difference between the sixth ultrasonic transducer in the reference measurement channel and the twelfth ultrasonic transducer in the target measurement channel (6) the signal processing module collects the sound wave attenuation coefficients a1, a2 and a3 of the reference measuring channel, and solves the volume fractions u1, u2 and u3 of each interfering gas component in the reference gas measuring cavity by simultaneously solving the sound attenuation equation set; The volume fractions u1, u2 and u3 of each interfering gas component in the reference gas are calculated according to the equation set (1); where i represents the i-th interfering gas, c is the sound speed of the gas, M is the relative molecular mass of the gas, R is the universal gas constant, f is the sound wave frequency, ω is the sound wave angular frequency, γ = C p / C v is the specific heat ratio, C p is the specific heat at constant pressure of the gas molecules, C v is the specific heat at constant volume of the gas molecules, μ' is the gas viscosity coefficient, k is the thermal conductivity, p0 and ρ0 are the static pressure and density of the gas, respectively, C v0 and C v∞ are the specific heat at constant volume of the gas under very high frequency excitation and without excitation, respectively, and τ is the gas relaxation time; in calculating the sound speed of the gas, the temperature T of the reference measurement channel is used for calculation, which has a certain effect on temperature compensation; (7) The signal processing module collects the ultrasonic phase difference of the reference measurement channel and the target measurement channel and Solve the target gas measurement cavity volume fraction u0' of the measured hydrogen gas and the volume fractions u1', u2', and u3' of each interfering gas component by simultaneously solving the sound velocity equation set. The volume fraction u0' of the to-be-tested hydrogen in the target gas is calculated according to the equation set (2): Wherein, L is the length of the reference gas measuring cavity and the target gas measuring cavity, and D is the diameter of the reference gas measuring cavity and the target gas measuring cavity; wherein, when calculating the sound speed of the gas, the temperature T' of the target measuring channel is calculated, which has a certain effect on temperature compensation.

2. The method of claim 1, wherein the concentration of hydrogen is selectively measured based on acoustic technology. The device used in the method comprises: A measuring cavity module comprising a reference gas measuring cavity and a target gas measuring cavity; An ultrasonic transceiver module comprising at least two pairs of ultrasonic transducers arranged in the reference gas measuring cavity and the target gas measuring cavity, respectively; A hydrogen adsorption module for adsorbing hydrogen in the to-be-tested gas; A signal generation module connected to the ultrasonic transceiver module for outputting homologous signals of different frequencies to the ultrasonic transducers; A signal processing module connected to the ultrasonic transceiver module for collecting and processing the received ultrasonic signals to obtain the hydrogen concentration; A part of the to-be-tested gas flows through the hydrogen adsorption module and then enters the reference gas measuring cavity, and another part of the to-be-tested gas enters the target gas measuring cavity.

3. The method of claim 2, wherein the acoustic-based selective measurement of hydrogen concentration is performed by, The ultrasonic transducers comprise three pairs of ultrasonic transducers arranged at the same positions in the reference gas measuring cavity and the target gas measuring cavity, respectively: one pair is placed at the two ends of the reference gas measuring cavity and the target gas measuring cavity along the axis, and the other two pairs are placed on the outer side of the wall surface of the reference gas measuring cavity and the target gas measuring cavity in an axisymmetric position; specifically: The first ultrasonic transducer and the second ultrasonic transducer are placed at the two ends of the reference gas measuring cavity along the axis, and the third ultrasonic transducer and the fourth ultrasonic transducer, and the fifth ultrasonic transducer and the sixth ultrasonic transducer are placed on the outer side of the wall surface of the reference gas measuring cavity in an axisymmetric position; The seventh ultrasonic transducer and the eighth ultrasonic transducer are placed at the two ends of the target gas measuring cavity along the axis, and the ninth ultrasonic transducer and the tenth ultrasonic transducer, and the eleventh ultrasonic transducer and the twelfth ultrasonic transducer are placed on the outer side of the wall surface of the target gas measuring cavity in an axisymmetric position.

4. The method of claim 3, wherein the acoustic-based selective measurement of hydrogen concentration is performed by, The signal generation module is connected to the first ultrasonic transducer and the seventh ultrasonic transducer, and outputs homologous signals of frequency f1; the signal generation module is connected to the third ultrasonic transducer and the ninth ultrasonic transducer, and outputs homologous signals of frequency f2; the signal generation module is connected to the fifth ultrasonic transducer and the eleventh ultrasonic transducer, and outputs homologous signals of frequency f3; The signal processing module is connected with the second ultrasonic transducer, the fourth ultrasonic transducer, the sixth ultrasonic transducer, the eighth ultrasonic transducer, the tenth ultrasonic transducer and the twelfth ultrasonic transducer.

5. The method of claim 2, wherein the acoustic-based selective measurement of hydrogen concentration is performed by, The hydrogen adsorption module comprises an adsorption material container and hydrogen adsorption material selected from AB5-type alloy, AB2-type alloy, AB-type alloy, A2B-type alloy, palladium-based material, metal hydride, carbonaceous material, coordination hydride, gas hydrate, porous carbon material, metal organic framework compound, microporous organic polymer or zeolite.

6. The method of claim 2, wherein the acoustic-based selective measurement of hydrogen concentration is performed by, The device comprises a dust and moisture removal module comprising a first dust and moisture removal device and a second dust and moisture removal device, the first dust and moisture removal device being connected with the gas inlet of the reference gas measuring cavity, and the second dust and moisture removal device being connected with the gas inlet of the target gas measuring cavity; the part of the gas to be measured flows into the reference gas measuring cavity through the hydrogen adsorption module and the first dust and moisture removal device in sequence.

7. The method of claim 6, wherein the acoustic-based selective measurement of hydrogen concentration is performed by, The first dust and moisture removal device and the second dust and moisture removal device are of the same structure and comprise a dust particle filter screen and a moisture removal agent.

8. The method of claim 2, wherein the acoustic-based selective measurement of hydrogen concentration is performed by, The device comprises a temperature measuring module arranged inside the reference gas measuring cavity and the target gas measuring cavity.

9. The method of claim 8, wherein the acoustic-based selective measurement of hydrogen concentration is performed by, The temperature measuring module comprises a first temperature sensor and a second temperature sensor, and the first temperature sensor and the second temperature sensor are arranged inside the reference gas measuring cavity and the target gas measuring cavity respectively.

10. The method of claim 1, wherein the method is based on acoustic technology. The range of f1, f2 and f3 is 1000 Hz to 100 MHz.

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