A device and method for monitoring calorific value of hydrogen-blended natural gas based on piezoelectric transducer

Abstract

The present invention discloses a calorific value monitoring device and method for hydrogen-blended natural gas based on a piezoelectric transducer, and belongs to the technical field of gas metering. A calorific value monitoring device for hydrogen-blended natural gas based on a piezoelectric transducer comprises a first ultrasonic generator, a first ultrasonic receiver, a second ultrasonic generator, a second ultrasonic receiver, a signal conversion module, a signal processing module and a calorific value calculation module; the first ultrasonic generator, the first ultrasonic receiver, the second ultrasonic generator and the second ultrasonic receiver are all installed inside a natural gas pipeline in an inclined shape, and the distance from the first ultrasonic generator to the first ultrasonic receiver is equal to the distance from the second ultrasonic generator to the second ultrasonic receiver. By collecting the time difference between the upstream and downstream of the sound wave in the natural gas pipeline, the time difference is used to calculate the sound velocity of the sound wave in the natural gas, and the concentration of hydrogen and methane in the natural gas is solved, and then the calorific value of the natural gas per unit volume is calculated.

Description

Technical Field

[0001] The present invention relates to the technical field of gas metering, and more specifically to a device and method for monitoring the calorific value of hydrogen-blended natural gas based on a piezoelectric transducer. Background Art

[0002] Hydrogen is often added to natural gas to effectively improve its combustion efficiency and reduce carbon emissions. However, existing measurement methods generally use volume measurement methods to measure natural gas. This method ignores the differences in the composition and calorific value of natural gas, resulting in all gases being traded and settled according to the same volume standard, which fails to reflect the true value of natural gas.

[0003] For example, the patent document with publication number CN116930318A provides a method for measuring the concentration of a mixed gas based on an ultrasonic flowmeter. In this method, a flowmeter with two groups of ultrasonic transducer groups is adopted, and the ultrasonic propagation paths of the two groups of ultrasonic transducer groups are cross-distributed. The relaxation absorption amplitude is used to measure the concentrations of hydrogen and methane respectively, and two groups of values ​​are obtained. The two groups of values ​​are then averaged to reduce errors and improve the accuracy of measuring gas concentration.

[0004] The detection method provided by the above literature can be used to measure the concentration of hydrogen and methane in natural gas, which is conducive to accurately determining the actual calorific value and true value of natural gas; however, in the calculation process, this method ignores the influence of temperature and pressure factors in the natural gas pipeline on the measurement accuracy, resulting in a deviation between the calculated result and the actual value. In view of this, we propose a hydrogen-blended natural gas calorific value monitoring device and method based on piezoelectric transducer. Summary of the invention

[0005] 1. Technical issues to be solved

[0006] The object of the present invention is to provide a device and method for monitoring the calorific value of hydrogen-blended natural gas based on a piezoelectric transducer to solve the problems raised in the above background technology.

[0007] 2. Technical solution

[0008] The present invention is achieved through the following technical solutions:

[0009] A device and method for monitoring the calorific value of hydrogen-blended natural gas based on a piezoelectric transducer, comprising a first ultrasonic generator, a first ultrasonic receiver, a second ultrasonic generator, a second ultrasonic receiver, a signal conversion module, a signal processing module and a calorific value calculation module;

[0010] The first ultrasonic generator, the first ultrasonic receiver, the second ultrasonic generator, and the second ultrasonic receiver are all installed inside the natural gas pipeline in an inclined state, and the distance from the first ultrasonic generator to the first ultrasonic receiver is equal to the distance from the second ultrasonic generator to the second ultrasonic receiver;

[0011] The first ultrasonic generator is coupled to the first ultrasonic receiver, and the transmitting end of the first ultrasonic generator faces the flow direction of the natural gas;

[0012] The second ultrasonic generator is coupled to the second ultrasonic receiver, and the transmitting end of the second ultrasonic generator faces the direction opposite to the flow of natural gas;

[0013] The first ultrasonic generator, the first ultrasonic receiver, the second ultrasonic generator, and the second ultrasonic receiver are all equipped with a pressure sensor and a temperature sensor;

[0014] The signal conversion module is electrically connected to the first ultrasonic receiver, the second ultrasonic receiver, the pressure sensor, and the temperature sensor, and is used to convert the physical signal into an electrical signal;

[0015] The signal processing module is electrically connected to the signal conversion module and is used to filter, amplify and remove noise from the received electrical signal;

[0016] The calorific value calculation module is electrically connected to the signal processing module and is used to calculate the calorific value of natural gas according to the electrical signal.

[0017] As an optional solution of the technical solution of the present application document, the first ultrasonic generator includes: a transducer housing, an acoustic impedance matching layer, a cylindrical piezoelectric ceramic element, a circuit board and a backing layer.

[0018] As an optional solution of the technical solution of the present application document, the operating frequencies of the first ultrasonic generator and the second ultrasonic generator are different.

[0019] As an optional solution of the technical solution of this application document, the operating frequency of the first ultrasonic generator is 200 KHz±5 KHz; the operating frequency of the second ultrasonic generator is 40 KHz±1 KHz.

[0020] As an optional solution of the technical solution of this application document, it also includes a calorific value detection module and a communication module;

[0021] The calorific value detection module is electrically connected to the calorific value calculation module and is configured to: obtain the hydrogen concentration in the natural gas and automatically trigger an alarm when the hydrogen concentration is abnormal;

[0022] The communication module is electrically connected to the calorific value detection module and is configured to receive data transmitted by the calorific value detection module and transmit the data to a monitoring center or a cloud platform.

[0023] A method for monitoring the calorific value of hydrogen-blended natural gas based on a piezoelectric transducer comprises the following steps:

[0024] S1. The first ultrasonic receiver and the second ultrasonic receiver collect the time of the sound wave flowing in the natural gas pipeline and the time of the sound wave flowing in the pipeline, and calculate the flow rate of the natural gas in the pipeline:

[0025] u=(L / t1-L / t2) / 2cosθ;

[0026] Where u is the flow rate of natural gas in the pipeline; L is the distance between the acoustic wave generator and the acoustic wave receiver, L=D / sinθ, D is the inner diameter of the pipeline, θ is the angle between the ultrasonic pulse direction and the natural gas flow rate; t1 is the time for the acoustic wave to flow downstream in the pipeline, and t2 is the time for the acoustic wave to flow upstream in the pipeline;

[0027] S2, collecting the temperature and pressure in the first ultrasonic generator, the first ultrasonic receiver, the second ultrasonic generator, and the second ultrasonic receiver, and correcting the flow rate of the natural gas in the pipeline;

[0028] U = λu;

[0029] Wherein, U is the corrected flow rate of natural gas in the pipeline, and λ is a correction coefficient, which depends on the temperature and pressure in the first ultrasonic generator, the first ultrasonic receiver, the second ultrasonic generator, and the second ultrasonic receiver;

[0030] S3. Calculate the speed of sound waves in stationary natural gas using the corrected flow rate of natural gas in the pipeline:

[0031] ;

[0032] Where c is the speed of sound waves in stationary natural gas;

[0033] S4. Calculate the concentration of hydrogen and methane in natural gas based on the relationship between sound velocity, concentration, specific heat capacity and molecular weight:

[0034] c 2 =r mix RT0 / M mix ;

[0035] r mix =(ρ a c pa +ρ b c pb ) / (ρ a c va +ρ b cvb );

[0036] M mix =ρ a M a +ρ b M b ;

[0037] ;

[0038] Where R is the universal gas constant, T0 is the temperature of natural gas in the pipeline under standard conditions, and ρ a is the percentage concentration of hydrogen in natural gas; ρ b is the percentage concentration of methane in natural gas; r mix is the specific heat capacity ratio of natural gas; c pa 、c va and M a are the specific heat at constant pressure, specific heat at constant volume and molecular weight of hydrogen respectively; c pb 、c vb and M b They are the specific heat at constant pressure, specific heat at constant volume and molecular weight of methane respectively;

[0039] S5. Calculate the calorific value per unit volume of natural gas based on the concentration of hydrogen and methane in the natural gas:

[0040] K=q a ρ a + q b ρ b :

[0041] Among them, q a is the calorific value of hydrogen, q b is the calorific value of methane.

[0042] As an optional solution of the technical solution of this application document, in S2, the correction coefficient is calculated using the following formula:

[0043] ;

[0044] Among them, α, β are constants, T i , P i The temperature and pressure are measured by each transducer, and T and P are the temperature and pressure of the gas under standard working conditions.

[0045] As an optional solution of the technical solution of this application document, it also includes:

[0046] S6. Use the integral method to calculate the calorific value of the natural gas flowing through the pipeline.

[0047] 3. Beneficial effects

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] 1) The present invention collects the time difference between the upstream and downstream sound waves in the natural gas pipeline, uses the time difference to calculate the speed of the sound wave in the natural gas, and solves the concentration of hydrogen and methane in the natural gas, and then calculates the calorific value of the natural gas per unit volume.

[0050] 2) The present invention collects the working temperature and pressure of the transducer assembly and corrects the calculated flow rate of the natural gas in the pipeline, thereby increasing the measurement accuracy and avoiding the adverse effects of temperature and pressure changes on the calculation accuracy of the calorific value of natural gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a schematic diagram of the installation structure of a hydrogen-blended natural gas calorific value monitoring device based on a piezoelectric transducer;

[0052] Figure 2 The schematic diagram of the transducer structure of a hydrogen-blended natural gas calorific value monitoring device based on a piezoelectric transducer;

[0053] Figure 3 It is a flow chart of a method for monitoring the calorific value of hydrogen-blended natural gas based on a piezoelectric transducer;

[0054] In the figure: 1. first ultrasonic generator; 2. first ultrasonic receiver; 3. second ultrasonic generator; 4. second ultrasonic receiver; 101. transducer housing; 102. acoustic impedance matching layer; 103. cylindrical piezoelectric ceramic element; 104. circuit board; 105. backing layer. DETAILED DESCRIPTION

[0055] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings.

[0056] Embodiment 1:

[0057] The present invention provides a calorific value monitoring device for hydrogen-blended natural gas based on a piezoelectric transducer, comprising a first ultrasonic generator 1, a first ultrasonic receiver 2, a second ultrasonic generator 3, a second ultrasonic receiver 4, a signal conversion module, a signal processing module, a calorific value calculation module, a calorific value detection module and a communication module;

[0058] like Figure 1 As shown, the first ultrasonic generator 1, the first ultrasonic receiver 2, the second ultrasonic generator 3, and the second ultrasonic receiver 4 are all installed inside the natural gas pipeline in an inclined state, and the distance from the first ultrasonic generator 1 to the first ultrasonic receiver 2 is equal to the distance from the second ultrasonic generator 3 to the second ultrasonic receiver 4;

[0059] The first ultrasonic generator 1 is coupled to the first ultrasonic receiver 2, and the transmitting end of the first ultrasonic generator 1 faces the direction of natural gas flow; the second ultrasonic generator 3 is coupled to the second ultrasonic receiver 4, and the transmitting end of the second ultrasonic generator 3 faces the direction opposite to the natural gas flow; the first ultrasonic generator 1 emits an ultrasonic wave which is received by the first ultrasonic receiver 2, and the second ultrasonic generator 3 emits an ultrasonic wave which is received by the second ultrasonic receiver 4, thereby measuring the time of the sound wave flowing upstream and downstream in the natural gas pipeline for subsequent calculation of the calorific value of the natural gas.

[0060] Pressure sensors and temperature sensors are installed inside the first ultrasonic generator 1, the first ultrasonic receiver 2, the second ultrasonic generator 3, and the second ultrasonic receiver 4. The pressure sensors and temperature sensors are used to detect the working status of the ultrasonic generator and the receiver, and are used to correct the time difference of the sound wave flowing upstream and downstream in the natural gas pipeline.

[0061] The signal conversion module is electrically connected to the first ultrasonic receiver 2, the second ultrasonic receiver 4, the pressure sensor, and the temperature sensor, and is used to convert the physical signal into an electrical signal; the signal processing module is electrically connected to the signal conversion module, and is used to filter, amplify and remove noise from the received electrical signal; the calorific value calculation module is electrically connected to the signal processing module, and is used to calculate the calorific value of natural gas based on the electrical signal; the calorific value detection module is electrically connected to the calorific value calculation module, and is configured to: obtain the hydrogen concentration in the natural gas, and automatically trigger an alarm when the hydrogen concentration is abnormal; the communication module is electrically connected to the calorific value detection module, and is configured to: receive the data transmitted by the calorific value detection module, and transmit it to the monitoring center or cloud platform.

[0062] like Figure 2 As shown, the first ultrasonic generator 1 includes: a transducer housing 101, an acoustic impedance matching layer 102, a cylindrical piezoelectric ceramic element 103, a circuit board 104 and a backing layer 105, and a pressure sensor and a temperature sensor are installed in the transducer housing 101; the first ultrasonic receiver 2, the second ultrasonic generator 3, and the second ultrasonic receiver 4 all adopt the same structure as the first ultrasonic generator 1. The transducer housing 101 is used to protect the internal core components, provide structural support and enhance signal transmission. The acoustic impedance matching layer 102 is optimized by using composite materials, and the sudden change of sound waves at the interface is reduced through the continuous change of its internal structure design, thereby achieving a smooth transition between different media, reducing reflection, and increasing the transmittance of the matching layer. The backing layer 105 is used to absorb the acoustic energy radiated by the cylindrical piezoelectric ceramic element 103 due to vibration to the inside of the probe, so as to prevent this part of the acoustic energy from being reflected back and transmitted to the piezoelectric element, thereby causing interference.

[0063] The piezoelectric ceramic parameters used by the cylindrical piezoelectric ceramic element 103 are shown in Table 1.

[0064] Table 1: Parameters of piezoelectric ceramic PSnN-5

[0065]

[0066] The selection of the operating frequency of the ultrasonic generator directly affects the measurement accuracy. Low-frequency sound waves have less energy loss during propagation, which allows the sound waves to propagate farther in water or air; while high-frequency ultrasonic waves have better directivity and resolution, but at the same time they decay faster. Therefore, the key to improving measurement accuracy is to reasonably select the operating frequency of the transducer. In order to avoid interference between different ultrasonic generators and receivers, ultrasonic generators and receivers with different operating frequencies are required. In combination with practical applications, the operating frequencies of the first ultrasonic generator 1 and the first ultrasonic receiver 2 used in the present invention are 200 KHz±5 KHz, and the operating frequencies of the second ultrasonic generator 3 and the second ultrasonic receiver 4 are 40 KHz±1 KHz.

[0067] Embodiment 2:

[0068] See also Figure 3 The present invention provides a method for monitoring the calorific value of hydrogen-blended natural gas based on a piezoelectric transducer, which is applied to a device for monitoring the calorific value of hydrogen-blended natural gas based on a piezoelectric transducer described in Example 1, and comprises the following steps:

[0069] S1, collecting the time of the sound wave flowing downstream and upstream in the natural gas pipeline through the first ultrasonic receiver 2 and the second ultrasonic receiver 4, and calculating the flow rate of the natural gas in the pipeline;

[0070] u=(L / t1-L / t2) / 2cosθ;

[0071] Where u is the flow rate of natural gas in the pipeline; L is the distance between the acoustic wave generator and the acoustic wave receiver, L=D / sinθ, D is the inner diameter of the pipeline, θ is the angle between the ultrasonic pulse direction and the natural gas flow rate; t1 is the time for the acoustic wave to flow downstream in the pipeline, and t2 is the time for the acoustic wave to flow upstream in the pipeline;

[0072] S2, collecting the temperature and pressure in the first ultrasonic generator 1, the first ultrasonic receiver 2, the second ultrasonic generator 3, and the second ultrasonic receiver 4, and correcting the flow rate of the natural gas in the pipeline;

[0073] U = λu;

[0074] ;

[0075] Among them, α and β are constants, Ti and Pi are the temperature and pressure measured by each transducer, T and P are the temperature and pressure of the gas under standard working conditions, which are 273.15 K and 101 KPa respectively;

[0076] S3. Use the corrected natural gas flow rate in the pipeline to calculate the speed of sound waves in stationary natural gas:

[0077] ;

[0078] Where c is the speed of sound waves in stationary natural gas;

[0079] S4. Based on the physical relationship between sound velocity, concentration, specific heat capacity and molecular weight, calculate the concentration of hydrogen and methane in natural gas:

[0080] c 2 =r mix RT0 / M mix ;

[0081] r mix =(ρ a c pa +ρ b c pb ) / (ρ a c va +ρ b c vb );

[0082] M mix =ρ a M a +ρ b M b ;

[0083] ;

[0084] Where c is the velocity of the sound wave in a stationary natural gas pipeline, R is the universal gas constant, T0 is the temperature of the natural gas in the pipeline under standard conditions, and ρ a is the percentage concentration of hydrogen in natural gas; ρ b is the percentage concentration of methane in natural gas; r mix is the specific heat capacity ratio of natural gas; c pa 、c va and M a are the specific heat at constant pressure, specific heat at constant volume and molecular weight of hydrogen respectively; c pb 、c vb and M b They are the specific heat at constant pressure, specific heat at constant volume and molecular weight of methane respectively;

[0085] S5. Calculate the calorific value per unit volume of natural gas based on the concentration of hydrogen and methane in the natural gas:

[0086] K=q a ρ a + q b ρ b :

[0087] Among them, q a is the calorific value of hydrogen, q b is the calorific value of methane;

[0088] S6. Use the integral method to calculate the calorific value of the natural gas flowing through the pipeline.

[0089] When sound waves propagate downstream and upstream in a natural gas pipeline, the following relationships exist:

[0090] t1=L / (c+ucosθ);

[0091] t2=L / (c-ucosθ);

[0092] L = D / sinθ;

[0093] According to the above formula, the formula for calculating the flow rate of natural gas in the pipeline in S1 can be obtained by transforming it;

[0094] u=(L / t1-L / t2) / 2cosθ;

[0095] Changes in temperature and pressure will affect the propagation speed of ultrasound in the fluid, because the speed of sound is directly related to the temperature and density of the medium. In order to avoid differences in measurement accuracy under different working conditions, the measured flow rate of natural gas in the pipeline needs to be corrected in S2.

[0096] In this application, the pressure sensor model used is WF5803F, the temperature sensor model is CWD200, α and β are 0.98 and 1.01 respectively; the above method is used to measure the flow rate of natural gas at different pressures, temperatures and flow rates in the pipeline, and the measurement results are shown in Table 2:

[0097] Table 2: Natural gas flow rate measurement table

[0098]

[0099] Since the speed of sound wave propagation in static natural gas is very fast and the measured time is short, the flow rate of sound wave in static natural gas is calculated by reverse and downstream time difference in S3 to eliminate some errors caused by temperature and pressure differences.

[0100] Combined with the influence of the molecular weight and specific heat capacity of the propagation medium on the speed of sound, the concentration of methane and hydrogen in natural gas is solved, and then the calorific value of natural gas per unit volume is calculated. Finally, based on the calorific value of natural gas per unit volume and the natural gas flow rate, the calorific value of the natural gas flowing through the natural gas pipeline is calculated using the integral method as a pricing reference to increase the rationality of natural gas billing.

Claims

1. A device for monitoring the calorific value of hydrogen-blended natural gas based on a piezoelectric transducer, characterized in that: It comprises a first ultrasonic generator (1), a first ultrasonic receiver (2), a second ultrasonic generator (3), a second ultrasonic receiver (4), a signal conversion module, a signal processing module and a calorific value calculation module; The first ultrasonic generator (1), the first ultrasonic receiver (2), the second ultrasonic generator (3), and the second ultrasonic receiver (4) are all installed in an inclined manner inside the natural gas pipeline, and the distance from the first ultrasonic generator (1) to the first ultrasonic receiver (2) is equal to the distance from the second ultrasonic generator (3) to the second ultrasonic receiver (4); The first ultrasonic generator (1) is coupled to the first ultrasonic receiver (2), and the transmitting end of the first ultrasonic generator (1) faces the flow direction of the natural gas; The second ultrasonic generator (3) is coupled to the second ultrasonic receiver (4), and the transmitting end of the second ultrasonic generator (3) faces in a direction opposite to the flow of natural gas; The first ultrasonic generator (1), the first ultrasonic receiver (2), the second ultrasonic generator (3), and the second ultrasonic receiver (4) are all equipped with a pressure sensor and a temperature sensor; The signal conversion module is electrically connected to the first ultrasonic receiver (2), the second ultrasonic receiver (4), the pressure sensor, and the temperature sensor, and is used to convert the physical signal into an electrical signal; The signal processing module is electrically connected to the signal conversion module and is used to filter, amplify and remove noise from the received electrical signal; The calorific value calculation module is electrically connected to the signal processing module and is used to calculate the calorific value of natural gas based on the electrical signal; The invention also includes a method for monitoring the calorific value of hydrogen-blended natural gas based on a piezoelectric transducer, which comprises the following steps: S1. The first ultrasonic receiver (2) and the second ultrasonic receiver (4) collect the time of the sound wave flowing in the natural gas pipeline and the time of the sound wave flowing in the pipeline, and calculate the flow rate of the natural gas in the pipeline: u=(L / t1 -L / t2) / 2cosθ; Where u is the flow rate of natural gas in the pipeline; L is the distance between the acoustic wave generator and the acoustic wave receiver, L=D / sinθ, D is the inner diameter of the pipeline, θ is the angle between the ultrasonic pulse direction and the natural gas flow rate; t1 is the time for the acoustic wave to flow downstream in the pipeline, and t2 is the time for the acoustic wave to flow upstream in the pipeline; S2, collecting the temperature and pressure in the first ultrasonic generator (1), the first ultrasonic receiver (2), the second ultrasonic generator (3), and the second ultrasonic receiver (4), and correcting the flow rate of the natural gas in the pipeline; U = λu; Wherein, U is the corrected flow rate of natural gas in the pipeline, and λ is a correction coefficient, which depends on the temperature and pressure in the first ultrasonic generator (1), the first ultrasonic receiver (2), the second ultrasonic generator (3), and the second ultrasonic receiver (4); S3. Calculate the speed of sound waves in stationary natural gas using the corrected flow rate of natural gas in the pipeline: ； Where c is the speed of sound waves in stationary natural gas; S4. Calculate the concentration of hydrogen and methane in natural gas based on the relationship between sound velocity, concentration, specific heat capacity and molecular weight: c 2 =r mix RT0 / M mix ; r mix =(ρ a c pa +r b c pb ) / (p a c va +r b c vb ); M mix =p a M a +r b M b ; ； Where R is the universal gas constant, T0 is the temperature of natural gas in the pipeline under standard conditions, and ρ a is the percentage concentration of hydrogen in natural gas; ρ b is the percentage concentration of methane in natural gas; r mix is the specific heat capacity ratio of natural gas; c pa 、c va and M a are the specific heat at constant pressure, specific heat at constant volume and molecular weight of hydrogen respectively; c pb 、c vb and M b They are the specific heat at constant pressure, specific heat at constant volume and molecular weight of methane respectively; S5. Calculate the calorific value per unit volume of natural gas based on the concentration of hydrogen and methane in the natural gas: K=q a ρ a + q b ρ b : Among them, q a is the calorific value of hydrogen, q b is the calorific value of methane; In S2, the correction factor is calculated using the following formula: ； Among them, α and β are constants, T i , P i The temperature and pressure are measured by each transducer, and T and P are the temperature and pressure of the gas under standard working conditions.

2. The device for monitoring the calorific value of hydrogen-blended natural gas based on a piezoelectric transducer according to claim 1, characterized in that: The first ultrasonic generator (1) comprises: a transducer housing (101), an acoustic impedance matching layer (102), a cylindrical piezoelectric ceramic element (103), a circuit board (104) and a backing layer (105).

3. The device for monitoring the calorific value of hydrogen-blended natural gas based on a piezoelectric transducer according to claim 1, characterized in that: The first ultrasonic generator (1) and the second ultrasonic generator (3) have different operating frequencies.

4. The device for monitoring the calorific value of hydrogen-blended natural gas based on a piezoelectric transducer according to claim 3 is characterized in that: The operating frequency of the first ultrasonic generator (1) is 200 KHz±5 KHz; the operating frequency of the second ultrasonic generator (3) is 40 KHz±1 KHz.

5. The device for monitoring the calorific value of hydrogen-blended natural gas based on a piezoelectric transducer according to claim 1, characterized in that: It also includes a calorific value detection module and a communication module; The calorific value detection module is electrically connected to the calorific value calculation module and is configured to: obtain the hydrogen concentration in the natural gas and automatically trigger an alarm when the hydrogen concentration is abnormal; The communication module is electrically connected to the calorific value detection module and is configured to receive data transmitted by the calorific value detection module and transmit the data to a monitoring center or a cloud platform.

6. The device for monitoring the calorific value of hydrogen-blended natural gas based on a piezoelectric transducer according to claim 1, characterized in that: Also includes: S6. Use the integral method to calculate the calorific value of the natural gas flowing through the pipeline.

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