A continuously adjustable natural gas extraction detection system and method

Abstract

This invention belongs to the field of gas turbine safety monitoring technology, and relates to a continuously adjustable natural gas extraction and detection system and method. The system includes a compressed air supply pipeline, a gas storage tank, a condensate drain device with a liquid level sensor and a drain valve, an electric regulating valve, a venturi tube, a gas analyzer, and a unit control system. The gas storage tank stabilizes compressed air pressure fluctuations, and the condensate drain device automatically drains water based on the liquid level signal to prevent moisture from entering the sampling system. The regulating valve is controlled by the unit control system to achieve continuous adjustment of the compressed air pressure, thereby precisely controlling the venturi tube extraction intensity. The sampled gas is filtered and then sent to the gas analyzer for detection; data feedback forms a closed-loop control. This invention solves the problems of unstable gas supply, moisture interference, and unadjustable extraction, significantly improving the response speed, accuracy, and operational reliability of natural gas leak detection.

Description

Technical Field

[0001] This invention belongs to the field of gas turbine safety monitoring technology, and relates to a continuously adjustable natural gas extraction and detection system and method. Background Technology

[0002] Gas turbines have wide applications in power generation, drive systems, and other industrial fields, but their operational safety has always been a major concern. During operation, components inside the gas turbine casing, such as fuel pipeline interfaces, valve seals, and turbine body sealing surfaces, can age or wear over time, potentially leading to natural gas leaks. Because gas turbine casings are typically semi-enclosed or enclosed, leaked natural gas cannot diffuse naturally. Once it accumulates inside and reaches the explosive limit, it can easily cause equipment explosions and serious safety accidents resulting in casualties. Therefore, achieving real-time extraction and accurate detection of natural gas inside the gas turbine casing has become a core technical challenge for ensuring the safe operation of gas turbines.

[0003] Currently, the industry mainly uses two sampling methods for natural gas leak detection, but both have significant technical drawbacks. The first is the diffusion sampling method, which involves installing gas sensors directly inside the gas turbine casing and relying on the natural diffusion of natural gas for detection. However, in practical applications, due to the complex structure of the equipment inside the casing, leaked gas can take several minutes or even tens of minutes to diffuse to the sensor location, resulting in a slow response time that may miss the optimal response opportunity. Furthermore, the high-temperature environment inside the casing, as well as contaminants such as metal dust and lubricating oil mist, can easily corrode and contaminate the sensor probe, leading to decreased detection accuracy or even signal anomalies. Sensors need to be replaced on average every 3-6 months, resulting in high maintenance costs. In addition, the effective monitoring range of a single sensor is limited; achieving comprehensive coverage requires a dense deployment of multiple sensors, increasing equipment investment and necessitating the laying of numerous power and signal cables, thus increasing construction complexity.

[0004] To overcome the shortcomings of diffusion sampling, the industry has developed active extraction sampling methods, which use a power unit to extract gas from the casing to an external analyzer for testing. This method mainly falls into two categories: sampling pump driven and compressed air driven. While the sampling pump driven method improves response speed, it carries the risk of mechanical failure. Its impeller and seals are prone to wear in high-temperature and high-humidity environments, typically requiring replacement every 1-2 years. Furthermore, the vibration generated by the pump operation may interfere with surrounding precision equipment. More importantly, the sampling pump has limited negative pressure; when the sampling pipeline length exceeds 10 meters, the extraction flow rate significantly decreases, making it difficult to meet the sampling requirements of large gas turbine casings. The compressed air driven method utilizes power plant instrumentation compressed air, generating negative pressure through a venturi tube to extract gas. While this improves reliability, it still faces several key technical challenges. Firstly, there is the issue of power source stability. Power plant compressed air sources need to power multiple devices simultaneously; fluctuations in air load can lead to unstable air source pressure, directly affecting the stability of the extracted flow rate, potentially causing abnormal test data or even extraction interruptions. Secondly, there is the issue of moisture interference from the air source. Condensate generated during the preparation and transportation of compressed air is difficult to remove effectively. Existing drainage methods are either prone to malfunction or fail to drain water in a timely manner, potentially allowing moisture to enter the sampling system, clogging pipelines or contaminating the analyzer. Finally, there is the issue of pressure regulation. The inlet pressure of the venturi tube is fixed, making it impossible to adjust the pumping intensity according to the leakage situation. In the case of a small leak, excessive pumping may dilute the sample, while in the case of a large leak, insufficient pumping will result in a slow response. Summary of the Invention

[0005] To address the problems in the prior art, this invention provides a continuously adjustable natural gas extraction and detection system and method, which significantly improves the response speed, accuracy, and operational reliability of natural gas leak detection.

[0006] To achieve the above objectives, the present invention employs the following technical solution: In a first aspect, the present invention provides a continuously adjustable natural gas extraction and detection system, comprising: Compressed air supply pipeline; An air storage tank, the air inlet of which is connected to the compressed air supply pipeline; A water-draining device includes a liquid level sensor and a water-draining valve; the liquid level sensor is mounted on the gas storage tank; the water-draining valve is located at the bottom of the gas storage tank and is connected to the gas storage tank. A regulating valve, the inlet of which is connected to the outlet of the gas storage tank; The venturi tube has its power air inlet connected to the outlet of the regulating valve, and its negative pressure sampling port extends to the area to be measured through a sampling pipeline. A gas analyzer, the inlet of which is connected to the mixed gas outlet of the venturi tube; The unit control system has its signal input terminal connected to the liquid level sensor and the gas analyzer, and its control signal output terminal connected to the drain valve and the regulating valve.

[0007] Preferably, the volume of the air storage tank is determined based on the pressure fluctuation characteristics of the compressed air supply pipeline and the system's stable operating time requirements.

[0008] Preferably, the volume calculation formula for the gas storage tank is:

[0009] In the formula, This refers to the volume of the gas storage tank; This represents the maximum pressure fluctuation value of compressed air. This refers to the system's instantaneous gas consumption. This is the initial pressure of the gas storage tank; This represents the minimum operating pressure for the system.

[0010] Preferably, it also includes a differential pressure sensor; the high-pressure side port of the differential pressure sensor is connected to the inlet pipe of the venturi tube, and the low-pressure side port is connected to the outlet pipe of the venturi tube.

[0011] Preferably, the unit control system and the audible and visual alarm device are connected.

[0012] Preferably, a filter assembly is provided at the inlet end of the sampling pipeline.

[0013] Preferably, the negative pressure sampling port of the venturi tube extends through the sampling pipeline to the natural gas accumulation area inside the gas turbine casing, and the natural gas accumulation area includes at least one of the gas turbine fuel valve assembly, sealing surface, or bottom corner of the casing.

[0014] Preferably, the liquid level sensor is a capacitive liquid level sensor or a float liquid level sensor.

[0015] Preferably, the regulating valve is an electric regulating valve.

[0016] Secondly, the present invention provides a continuously adjustable natural gas extraction and detection method, comprising the following steps: Compressed air is supplied to the air storage tank through the compressed air supply pipeline; The air storage tank is used to buffer the input compressed air to stabilize its pressure fluctuations and to cause the moisture in the compressed air to condense and accumulate at the bottom of the tank. The liquid level sensor monitors the condensate level in the gas storage tank in real time and transmits the liquid level signal to the unit control system. When the liquid level reaches the preset upper limit, the unit control system controls the drain valve to open for drainage. When the liquid level drops to the preset lower limit, the unit control system controls the drain valve to close. The unit control system outputs a control signal to the regulating valve to regulate the pressure and flow rate of the compressed air flowing from the air storage tank to the venturi tube; The regulated compressed air flows through the venturi tube and generates negative pressure at its negative pressure sampling port through the jet effect, thereby drawing the gas to be tested from the area to be tested through the sampling pipeline; the gas to be tested and the compressed air are mixed in the venturi tube to form a mixed gas output. The mixed gas output from the venturi tube is delivered to the gas analyzer, which analyzes the concentration of natural gas in the mixed gas and feeds back the concentration analysis signal to the unit control system.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention effectively mitigates pressure fluctuations from the external compressed air source by installing a gas storage tank, thereby improving gas supply stability. Through the linkage control of a liquid level sensor and a drain valve, precise discharge of condensate is achieved, preventing moisture from entering downstream pipelines and causing blockages or contamination. By using a closed-loop control system to regulate the opening of the regulating valve, the controllability of compressed air pressure and the flow rate of the gas being measured is achieved, thus ensuring stable venturi pumping intensity. Overall, this invention improves the response speed, detection accuracy, and system reliability of natural gas detection. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of a continuously adjustable natural gas extraction and detection system according to the present invention.

[0020] The components include: 1. Compressed air supply pipeline; 2. Air storage tank; 3. Drainage device; 31. Liquid level sensor; 32. Drainage valve; 4. Regulating valve; 5. Venturi tube; 6. Sampling pipeline; 7. Differential pressure sensor; 8. Gas analyzer. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0023] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0024] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention 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, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0025] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0026] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0027] The present invention will now be described in further detail with reference to the accompanying drawings: The first objective of this invention is to provide a continuously adjustable natural gas extraction and detection system, such as... Figure 1 As shown, it includes: Compressed air supply line 1; The air storage tank 2 has its air inlet connected to the compressed air supply pipeline 1; The drainage device 3 includes a liquid level sensor 31 and a drainage valve 32; the liquid level sensor 31 is disposed on the gas storage tank 2; the drainage valve 32 is disposed at the bottom of the gas storage tank 2 and is connected to the gas storage tank 2. The regulating valve 4 has its inlet connected to the outlet of the gas storage tank 2; The Venturi tube 5 has its power air inlet connected to the outlet of the regulating valve 4, and its negative pressure sampling port extends to the area to be tested through the sampling pipeline 6. The gas analyzer 8 has its inlet connected to the mixed gas outlet of the venturi tube 5; The unit control system has its signal input terminal connected to the liquid level sensor 31 and the gas analyzer 8, and its control signal output terminal connected to the drain valve 32 and the regulating valve 4.

[0028] The compressed air supply line 1 is used to introduce an external instrument compressed air source into the system, serving as the power source for the entire detection process. The air storage tank 2 is connected to the compressed air supply line 1 through its air inlet. It receives compressed air from upstream sources with large pressure fluctuations and forms a buffer space of a certain volume inside, thereby effectively smoothing out instantaneous pressure changes and improving the stability of downstream air supply. The air storage tank 2 can be made of pressure-resistant steel, and its geometry can be a vertical cylindrical shape or a horizontal elliptical head structure to adapt to on-site installation conditions.

[0029] The condensate trap 3 is used to remove condensate that precipitates from compressed air after cooling in the gas storage tank 2, preventing moisture from entering subsequent pipelines with the airflow and causing corrosion, blockage, or interference with gas analysis results. This device includes a level sensor 31 and a condensate trap 32. The level sensor 31 is installed on the outer wall of the gas storage tank 2 or has an internal probe, enabling real-time sensing of the condensate level inside the tank and transmitting analog or digital signals to the unit control system. The condensate trap 32 is located at the lowest point of the bottom of the gas storage tank 2, ensuring complete drainage of accumulated water. It is connected to the gas storage tank 2 and controlled by the unit control system to automate its opening and closing actions. The level sensor 31 is a capacitive or float-type level sensor, which detects the liquid level through capacitive sensing or float mechanical transmission, featuring fast response and strong anti-interference capabilities.

[0030] The regulating valve 4 is located downstream of the outlet of the gas storage tank 2, with its inlet connected to the gas storage tank 2. It is used to precisely regulate the pressure of the compressed air flowing to the venturi tube 5 and the flow rate of the detected hazardous gas. The regulating valve 4 has continuous adjustment capability and can dynamically adjust its opening according to system requirements to avoid abnormal pumping efficiency due to excessively high or low gas source pressure.

[0031] The Venturi tube 5 is a fluid dynamic element operating based on the Venturi effect. Its power gas inlet is connected to the outlet of the regulating valve 4. When compressed air flows at high speed through the throat, a local negative pressure is generated, thereby extracting gas samples from the external test area through the negative pressure sampling port. For example, one end of the sampling pipeline 6 is connected to this negative pressure sampling port, and the other end extends to areas inside the gas turbine casing where natural gas may accumulate, such as near the fuel valve assembly, around the sealing surface, or at the bottom corner, achieving targeted and directional sampling. The Venturi tube 5 can be made entirely of stainless steel or aluminum alloy, and its internal flow channels are precision-machined to ensure stable aerodynamic performance.

[0032] Gas analyzer 8 receives the mixed gas (i.e., a mixture of compressed air and the extracted gas) output from venturi tube 5 and determines the volume concentration of natural gas (mainly methane) in it using infrared absorption, catalytic combustion, or other applicable methods. The analysis results are fed back to the unit control system in the form of an electrical signal, serving as an important basis for determining whether a leak exists.

[0033] The unit control system, as the central control unit of the entire system, possesses dual functions of data acquisition and logic control. Its signal input terminals are connected to the liquid level sensor 31 and the gas analyzer 8, enabling real-time acquisition of the liquid level in the gas storage tank 2 and the natural gas concentration in the sampled gas. Its control signal output terminals are connected to the drain valve 32 and the regulating valve 4, allowing it to issue control commands based on preset thresholds or operating strategies. For example, when the liquid level sensor 31 detects that the condensate has reached the high limit setting, the control system automatically opens the drain valve 32 to drain the condensate, and closes the valve when the liquid level drops back to the low limit. Simultaneously, the control system can dynamically adjust the opening of the regulating valve 4 based on data from the gas analyzer 8 to maintain a stable pumping rate and analysis conditions.

[0034] For example, the volume of the air storage tank 2 is determined based on the pressure fluctuation characteristics of the compressed air supply pipeline 1 and the system's stable operating time requirements. The formula for calculating the volume of the air storage tank 2 is as follows:

[0035] In the formula, This refers to the volume of the gas storage tank; This represents the maximum pressure fluctuation value of compressed air. This refers to the system's instantaneous gas consumption. This is the initial pressure of the gas storage tank; This represents the minimum operating pressure for the system.

[0036] when Increase or When the temperature rises, in order to maintain the same steady-state time, the pressure must be increased. Conversely, if and If the difference is large, then it can be smaller. Under the same conditions, it achieves the same energy storage effect. Therefore, this formula is essentially an energy conservation expression based on the ideal gas law, reflecting the minimum volume constraint condition for meeting transient gas demand within a limited pressure variation range. This formula makes gas storage capacity no longer dependent on subjective experience or excessive redundancy configuration, solving the problem of gas supply interruption and response delay in the detection system caused by insufficient estimation of gas source fluctuations in traditional designs.

[0037] The system of this invention also includes a differential pressure sensor 7; the differential pressure sensor 7 is a sensing device used to measure the pressure difference between two measuring points, and is used to collect the flow signal of the gas to be measured. Its high-pressure side port is connected to the inlet pipe of the Venturi tube 5, that is, the upstream pipe before the compressed air enters the Venturi tube 5; the low-pressure side port is connected to the outlet pipe of the Venturi tube 5, that is, the downstream pipe from which the gas mixture flows out, used to obtain the pressure level of the outlet gas. The differential pressure sensor 7 can be manufactured using piezoresistive, capacitive, or silicon resonant principles, and has high sensitivity, good temperature stability, and anti-electromagnetic interference capabilities, making it suitable for long-term reliable operation in complex industrial environments.

[0038] The Venturi tube 5, as the core component utilizing the Bernoulli effect to generate negative pressure, has an internal flow channel with a contraction-throat-expansion structure. When compressed air flows at high speed through the throat, a local low-pressure zone is formed, thereby drawing the gas to be measured from the outside through the negative pressure sampling port. During this process, the pressure difference between the inlet and outlet directly reflects the flow rate of the gas to be measured, thus determining the strength of the negative pressure generation capability. Therefore, the pressure difference value measured by the differential pressure sensor 7 can serve as an important indicator for evaluating the operating performance of the Venturi tube 5: under normal operating conditions, it should maintain a stable differential pressure range; if the differential pressure decreases significantly or even approaches zero, it may indicate abnormal conditions such as the front-end regulating valve 4 not being open or the gas supply from the gas tank 2 being interrupted.

[0039] For example, the differential pressure sensor 7 is also connected to the unit control system, enabling it to continuously feed back real-time differential pressure signals to the unit control system. The unit control system can issue continuous adjustment commands to the regulating valve 4 based on preset PI (Proportional-Integral) parameters, achieving closed-loop control and further improving the response accuracy and robustness of the gas analyzer 8.

[0040] The unit control system is connected to the audible and visual alarm device. The unit control system outputs an alarm signal based on the natural gas concentration. For example, when the detected concentration exceeds a set limit, the unit control system immediately generates an alarm trigger signal. This unit control system can be implemented using a PLC (Programmable Logic Controller), DCS (Distributed Control System), or a dedicated embedded controller, possessing good anti-interference capabilities and adaptability to industrial environments. Furthermore, the audible and visual alarm device can be linked with other safety interlock systems, such as triggering the start of ventilation equipment, closing fuel valves, or executing emergency shutdown procedures, thus forming a complete safety protection chain.

[0041] The inlet of the sampling pipeline 6 is equipped with a filter assembly. This filter assembly removes impurities such as solid particles, oil mist, and liquid droplets carried in the gas to be tested through physical interception, preventing these contaminants from entering the Venturi tube 5 and the subsequent gas analyzer 8 with the airflow. The filter assembly can adopt a porous media structure, and its core filter element can be selected from sintered metal filter elements, ceramic filter tubes, polymer microporous membranes, or fiber woven meshes, etc., with a filtration accuracy of not less than 5μm to ensure effective interception of the vast majority of suspended particles.

[0042] The regulating valve 4 is an electrically operated regulating valve. The working mechanism of the electrically operated regulating valve depends on the deviation between the actual differential pressure data collected by the unit control system and the set target value. The unit control system uses the PI (Proportional-Integral) algorithm to calculate the output control quantity based on this deviation: the proportional action quickly responds to instantaneous errors, and the integral action eliminates steady-state deviations. The combination of the two makes the regulation process both rapid and stable.

[0043] A second objective of this invention is to provide a continuously adjustable natural gas extraction and detection method, comprising the following steps: S1. Compressed air is supplied to the air storage tank 2 through the compressed air supply pipeline 1; The compressed air supply line 1 connects to an external instrument compressed air source to introduce high-pressure air into the system. This compressed air source typically comes from the instrument air system in a power plant or industrial site.

[0044] S2. The compressed air is buffered by the air storage tank 2 to stabilize its pressure fluctuations and to cause the moisture in the compressed air to condense and accumulate at the bottom of the tank. When compressed air enters the air storage tank 2, due to the reduced flow rate and extended residence time, the water vapor carried in the gas undergoes a phase change due to the temperature drop, forming liquid condensate which is deposited at the bottom of the tank. Simultaneously, the air storage tank 2 acts as a buffer, absorbing pressure fluctuations from the upstream air source and reducing pressure shocks to downstream equipment.

[0045] S3. The liquid level sensor 31 monitors the condensate level in the gas storage tank 2 in real time and transmits the liquid level signal to the unit control system. When the liquid level reaches the preset upper limit, the unit control system controls the drain valve 32 to open for drainage. When the liquid level drops to the preset lower limit, the unit control system controls the drain valve 32 to close. S4. The unit control system outputs a control signal to the regulating valve 4 to regulate the pressure and flow rate of the compressed air flowing out of the gas storage tank 2 and onto the venturi tube 5, thereby controlling the flow rate of the gas to be measured through the venturi tube 5. The unit control system generates control commands based on preset target parameters or real-time feedback data, and dynamically adjusts the opening of regulating valve 4 through PID algorithm to make the flow rate of the gas to be measured entering venturi tube 5 continuously adjustable.

[0046] S5. The regulated compressed air flows through the Venturi tube 5 and generates negative pressure at its negative pressure sampling port through the jet effect, thereby extracting the gas to be tested from the area to be tested through the sampling pipeline 6; the gas to be tested and the compressed air are mixed in the Venturi tube 5 to form a mixed gas output. S6. The mixed gas output from the Venturi tube 5 is delivered to the gas analyzer 8, which analyzes the concentration of natural gas in the mixed gas and feeds back the concentration analysis signal to the unit control system. Gas analyzer 8 is used to detect the volume concentration of combustible gases such as methane in a gas mixture. It can employ various technologies, including non-dispersive infrared (NDIR), catalytic beam, or laser spectroscopy. NDIR analyzers offer advantages such as high selectivity, long lifespan, and immunity to background gas interference, making them suitable for high-precision monitoring applications. Analysis results are fed back to the unit control system in real-time as electrical signals to determine the presence and extent of natural gas leaks. When the concentration exceeds a preset alarm threshold, the unit control system can activate audible and visual alarms or initiate an emergency shutdown procedure to ensure equipment and personnel safety. Additionally, the system can be equipped with a differential pressure sensor 7, with its high-pressure side port connected to the inlet of the venturi tube 5 and its low-pressure side port connected to the outlet, used to monitor the jet gas flow status and detect the flow rate of the gas to be measured.

[0047] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A continuously adjustable natural gas extraction and detection system, characterized in that, include: Compressed air supply pipeline (1); An air storage tank (2) has its air inlet connected to the compressed air supply pipeline (1); The water-draining device (3) includes a liquid level sensor (31) and a water-draining valve (32); the liquid level sensor (31) is installed on the gas storage tank (2); the water-draining valve (32) is installed at the bottom of the gas storage tank (2) and is connected to the gas storage tank (2); The regulating valve (4) has its inlet connected to the outlet of the gas storage tank (2); The Venturi tube (5) has its power air inlet connected to the outlet of the regulating valve (4), and its negative pressure sampling port extends to the area to be measured through the sampling pipeline (6); The gas analyzer (8) has its inlet connected to the mixed gas outlet of the venturi tube (5); The unit control system has its signal input terminal connected to the liquid level sensor (31) and the gas analyzer (8), and its control signal output terminal connected to the drain valve (32) and the regulating valve (4).

2. The continuously adjustable natural gas extraction and detection system according to claim 1, characterized in that, The volume of the air storage tank (2) is determined based on the pressure fluctuation characteristics of the compressed air supply pipeline (1) and the system's stable operating time requirements.

3. The continuously adjustable natural gas extraction and detection system according to claim 2, characterized in that, The volume calculation formula for the gas storage tank (2) is as follows: In the formula, This refers to the volume of the gas storage tank; This represents the maximum pressure fluctuation value of compressed air. This refers to the system's instantaneous gas consumption. This is the initial pressure of the gas storage tank; This represents the minimum operating pressure for the system.

4. The continuously adjustable natural gas extraction and detection system according to claim 1, characterized in that, It also includes a differential pressure sensor (7); the high-pressure side port of the differential pressure sensor (7) is connected to the inlet pipe of the venturi tube (5), and the low-pressure side port is connected to the outlet pipe of the venturi tube (5).

5. The continuously adjustable natural gas extraction and detection system according to claim 1, characterized in that, The unit's control system and audible and visual alarm device are connected.

6. The continuously adjustable natural gas extraction and detection system according to claim 1, characterized in that, A filter assembly is provided at the inlet end of the sampling pipeline (6).

7. The continuously adjustable natural gas extraction and detection system according to claim 1, characterized in that, The negative pressure sampling port of the Venturi tube (5) extends through the sampling pipeline (6) to the natural gas accumulation area inside the gas turbine casing, the natural gas accumulation area including at least one of the gas turbine fuel valve group, sealing surface or bottom corner of the casing.

8. The continuously adjustable natural gas extraction and detection system according to claim 1, characterized in that, The liquid level sensor (31) is a capacitive liquid level sensor or a float liquid level sensor.

9. The continuously adjustable natural gas extraction and detection system according to claim 1, characterized in that, The regulating valve (4) is an electric regulating valve.

10. A continuously adjustable method for natural gas extraction and detection, characterized in that, The system based on any one of claims 1 to 9 includes the following steps: Compressed air is supplied to the air storage tank (2) through the compressed air supply pipeline (1); The compressed air is buffered by the air storage tank (2) to stabilize its pressure fluctuations and to cause the moisture in the compressed air to condense and accumulate at the bottom of the tank. The liquid level sensor (31) monitors the condensate level in the gas storage tank (2) in real time and transmits the liquid level signal to the unit control system. When the liquid level reaches the preset upper limit, the unit control system controls the drain valve (32) to open for drainage. When the liquid level drops to the preset lower limit, the unit control system controls the drain valve (32) to close. The unit control system outputs a control signal to the regulating valve (4) to regulate the pressure and flow rate of the compressed air flowing out of the air tank (2) and into the venturi tube (5); The regulated compressed air flows through the Venturi tube (5) and generates negative pressure at its negative pressure sampling port through the jet effect, thereby extracting the gas to be tested from the area to be tested through the sampling pipeline (6); the gas to be tested and the compressed air are mixed in the Venturi tube (5) to form a mixed gas output. The mixed gas output from the venturi tube (5) is delivered to the gas analyzer (8), which analyzes the concentration of natural gas in the mixed gas and feeds back the concentration analysis signal to the unit control system.

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