TDLAS (tunable diode laser absorption spectroscopy)-based methane and VOCs (volatile organic compounds) collaborative detection system and detection method

Abstract

The invention discloses a TDLAS (Tunable Diode Laser Absorption Spectroscopy)-based methane and VOCs (Volatile Organic Compounds) collaborative detection system and detection method, and relates to the technical field of oil and gas field methane and VOCs detection, the system comprises a sampling module, a data measurement module and a display module; the sampling module is connected with the data measurement module through a pipeline, and the display module performs data interaction with the sampling module and the data measurement module in a wireless mode; wherein the sampling module is used for sampling background gas and leakage gas; the data measurement module is used for measuring the sampled background gas and leakage gas; and the display module is used for displaying the concentration of the background gas and the leakage gas. According to the system and the method disclosed by the invention, the cooperative measurement of methane and VOCs can be realized, the detection efficiency is effectively improved, and targeted cooperative management and control of methane and VOCs are carried out.

Description

Technical Field

[0001] The present invention relates to the technical field of methane and VOCs detection in oil and gas fields, and in particular to a methane and VOCs collaborative detection system and detection method based on TDLAS. Background Art

[0002] The "Emission Standards of Air Pollutants for Onshore Petroleum and Natural Gas Exploitation Industry" (GB 39728-2020), which was implemented in January 2021, proposed for the first time the control requirements for methane and VOCs (Volatile Organic Compounds) in conventional oil and gas fields. The simultaneous detection of methane and VOCs is the basis of control. The control of methane and VOCs in domestic oil and gas fields is still in its infancy and has a large application market. The core device of the gas detector is the detection sensor. Tunable Diode Laser Absorption Spectroscopy (TDLAS) is a technology that has gradually matured in recent years. It uses a tunable diode laser as a light source and obtains the concentration of the gas to be measured by the absorption intensity of the measured component to light of a specific wavelength.

[0003] The utility model patent with Chinese patent application number "CN201720119383.3" discloses "Toxic and Hazardous Gas Online Monitoring System Based on TDLAS Technology". The system includes a laser gas analyzer and a pipeline online optical-mechanical structure. The laser gas analyzer includes a semiconductor laser, a signal processing board, and a main control board. The pipeline online optical-mechanical structure is divided into two types: the beam type and the reflection type, which are suitable for online monitoring in industrial production. This patent can achieve the purpose of measuring multiple positions with a laser gas analyzer, but it cannot achieve the simultaneous measurement of two or more gases.

[0004] The invention patent with Chinese patent application number "CN201911052941.9" discloses "a detection device and detection method of methane gas concentration based on TDLAS". The device includes a coverless housing, a power supply, a data acquisition module, a circuit control room, a laser transceiver room and a porous ceramic gas chamber, which is suitable for detecting methane gas concentration in rice fields. The patent only realizes a single measurement of methane.

[0005] The utility model patent with Chinese patent application number "CN202023158898.5" discloses "a methane leakage monitoring system based on TDLAS technology". The device contains a CPU, a gas detection module, a wireless data acquisition module, a signal processing module, a data acquisition gateway, a pan / tilt, a methane laser telemetry terminal, a data analysis module, a laser module and a data storage module, which can realize long-distance methane leakage monitoring. The patent only realizes a single measurement of methane.

[0006] The invention patent with Chinese patent application number "CN202110569178.8" discloses a "gas leakage telemetry system based on TDLAS", which includes a laser transmitter and receiver, a starlight-level video camera module, a data acquisition gateway, a pan / tilt, a local workstation, a 5G base station and a data center, and is a gas telemetry system. This patent only realizes online monitoring of leaking gas, and cannot realize detection near the leak source.

[0007] The master's thesis "Research on the Method of Online Detection of VOCs by Tuned Laser Spectroscopy and Instrument Design" designed an experimental system for online detection of VOCs based on TDLAS technology, including signal generator, laser driver, laser and collimator, long optical path gas cell, photodetector and preamplifier, phase-locked amplifier, data acquisition card, data storage and processing unit, etc. It improved the traditional TDLAS system structure, expanded the detection range of TDLAS technology, and can realize continuous, rapid and on-site analysis of VOCs. This document only achieved a single measurement of VOCs.

[0008] The above patents and research results only measure methane or VOCs, and cannot achieve simultaneous measurement of methane and VOCs, or cannot detect leaking gas near the leak source. At present, two types of instruments are required for methane and VOCs emission detection at oil and gas field stations, one is a methane detector, and the other is a volatile organic compound detector. In oil and gas field production platforms, transfer stations, joint stations, processing stations and oil depots, methane and VOCs come from the same emission source. Using two instruments for detection is inefficient, time-consuming and labor-intensive. The methane or VOCs leak detectors on the market mainly target one gas and do not meet the current emission characteristics of oil and gas fields. Summary of the invention

[0009] The purpose of the present invention is to provide a methane and VOCs collaborative detection system and detection method based on TDLAS, which can realize the collaborative measurement of methane and VOCs, effectively improve the detection efficiency, and carry out targeted methane and VOCs collaborative management and control. To achieve the above purpose, the present invention provides the following technical solutions:

[0010] The present invention provides a methane and VOCs collaborative detection system based on TDLAS, the detection system comprising: a sampling module, a data measurement module and a display module; the sampling module is connected to the data measurement module through a pipeline, and the display module performs data exchange with the sampling module and the data measurement module in a wireless manner; wherein,

[0011] The sampling module is used to sample background gas and leaked gas;

[0012] The data measurement module is used to measure the sampled background gas and leaked gas;

[0013] The display module is used to display the concentration of background gas and leaked gas.

[0014] As a preferred embodiment, the sampling module includes: a micro gas sampling pump, a background gas inlet, a gas sampler, a sampling hose and connecting accessories; wherein,

[0015] The background gas inlet is arranged on the explosion-proof housing of the detection device and is connected to a micro gas sampling pump through a pipeline for sampling the background gas;

[0016] The middle part of the gas sampler is located in the accommodating space of the explosion-proof housing of the detection device, and the two ports are located outside the explosion-proof housing of the detection device. The gas sampler is connected to the connecting accessories through a sampling hose for sampling the leaked gas.

[0017] As a preferred embodiment, the gas sampler includes an inlet filter screen, a gas sampling point, a large flow gas sampling pump and a first gas outlet; wherein,

[0018] The inlet filter screen is arranged at one end of the gas sampler and is connected to a large flow gas sampling pump through a pipeline;

[0019] The gas sampling point is arranged on the side wall of the gas sampler;

[0020] The first gas outlet is arranged at the other end of the gas sampler.

[0021] As a preferred embodiment, the data measurement module includes: a circuit board, a first solenoid valve, a second solenoid valve, a first TDLAS sensor, a second TDLAS sensor and a second gas outlet; wherein,

[0022] The first solenoid valve and the second solenoid valve are both welded on the circuit board. The first solenoid valve is connected to the background gas inlet, the gas sampling point and the micro gas sampling pump through pipelines; the second solenoid valve is connected to the micro gas sampling pump, the first TDLAS sensor and the second TDLAS sensor through pipelines; the first TDLAS sensor and the second TDLAS sensor are both connected to the second gas outlet through pipelines.

[0023] As a preferred implementation, the display module includes a handheld terminal and a menu button; wherein,

[0024] The menu button is arranged on the handheld terminal.

[0025] As a preferred implementation, the detection system further comprises: a power supply module and a safety module; the power supply module and the safety module are connected; wherein,

[0026] The power supply module is used to supply power to the sampling module, the data measurement module and the display module;

[0027] The safety module is used to ensure the safety of the power supply module.

[0028] As a preferred implementation, the power supply module includes a rechargeable battery and a plurality of connecting wires; wherein the rechargeable battery is connected to the explosion-proof housing of the detection device via the connecting wires.

[0029] As a preferred implementation, the safety module includes an explosion-proof housing of the detection device and a grounding wire; wherein the grounding wire is connected to the explosion-proof housing of the detection device.

[0030] The present invention also provides a TDLAS-based methane and VOCs collaborative detection method, the method comprising the following steps:

[0031] Step (1), after the safety module is grounded, the sampling module is started to sample the background gas; then the data measurement module is started to measure the background gas; finally, the display module displays the concentration of methane and VOCs in the background gas;

[0032] Step (2), using the detection system to inspect the dynamic and static sealing points of the enterprise equipment, or using a gas imaging infrared camera to observe gas leakage at oil and gas field stations;

[0033] Step (3), where a gas leak is found, select a suitable connection accessory according to the shape and size of the component, connect the connection accessory to the location of the leak source, and use the detection system to collect all leaked gases;

[0034] Step (4), start the sampling module to sample the leaked gas; then start the data measurement module to measure the leaked gas; finally, the display module displays the concentration of methane and VOCs in the leaked gas.

[0035] As a preferred embodiment, the dynamic and static sealing points include: a pump, a compressor, an agitator, a valve, a pressure relief device sampling connection system, an open valve, an open pipeline, a flange and a connector.

[0036] Technical effects and advantages of the present invention:

[0037] First, the high-sensitivity TDLAS detector used in the present invention has the advantages of accurate linear response range of methane and VOCs, good selectivity, high reliability, no poisoning, no dependence on oxygen, little environmental interference factors, no need for regular calibration, wide operating temperature range, and strong field adaptability;

[0038] Second, the present invention uses a dual-range (TDLAS) sensor combination to achieve simultaneous measurement of methane and VOCs concentrations during operation, thereby improving work efficiency.

[0039] Third, the large-flow gas sampling pump used in the detection system of the present invention performs measurement by actively suctioning air at a large flow rate, and can detect tiny leakage sources.

[0040] Other features and advantages of the present invention will be described in the following description, and partly become obvious from the description, or be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 Schematic diagram of a methane and VOCs collaborative detection system based on TDLAS according to an embodiment of the present invention;

[0042] Figure 2 This is a schematic diagram of the overall structure of a methane and VOCs collaborative detection system based on TDLAS according to an embodiment of the present invention;

[0043] Figure 3 This is a schematic diagram of the partial structure of a methane and VOCs collaborative detection system based on TDLAS according to an embodiment of the present invention;

[0044] In the figure, 101, sampling module; 102, data measurement module; 103, display module; 104, power supply module; 105, safety module; 1, explosion-proof housing of detection device; 2, handheld terminal; 3, rechargeable battery; 4, grounding wire; 11, gas sampler; 12, circuit board; 111, inlet filter screen; 112, gas sampling point; 113, large-flow gas sampling pump; 114, first gas outlet; 121, first solenoid valve; 122, micro gas sampling pump; 123, second solenoid valve; 124, first TDLAS sensor; 125, second TDLAS sensor; 126, second gas outlet; 127, background gas inlet; 21, menu button; 22, sampling hose; 23, connecting accessories. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] In the description of the present invention, it should be noted that the specific methods and conditions not specified are conventional methods known in the art, or methods recommended by instrument manufacturers. Unless otherwise clearly specified and limited, the terms "install", "connect", and "connect" are broad in meaning, for example, fixed connection, detachable connection, mechanical connection, electrical connection, connection through an intermediate medium, and internal communication between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0047] In order to solve the deficiencies of the prior art, the present invention discloses a methane and VOCs collaborative detection system based on TDLAS. Figure 1 FIG. 1 is a schematic diagram of a methane and VOCs collaborative detection system based on TDLAS according to an embodiment of the present invention. Figure 1 As shown, the detection system is divided into functions, including: a sampling module 101, a data measurement module 102, a display module 103, a power supply module 104 and a safety module 105; the sampling module 101 is connected to the data measurement module 102 through a pipeline, and the display module 103 exchanges data with the sampling module 101 and the data measurement module 102 in a wireless manner; the power supply module 104 is used to provide a power source for the sampling module 101, the data measurement module 102 and the display module 103; the safety module 105 is used to provide safety protection for the power supply module 104; wherein,

[0048] The sampling module 101 includes: a micro gas sampling pump 122, a background gas inlet 127, a gas sampler 11, a sampling hose 22 and a connecting accessory 23; wherein the background gas inlet 127 is arranged on the explosion-proof casing 1 of the detection device, and is connected to the micro gas sampling pump 122 through a pipeline for sampling the background gas; the middle part of the gas sampler 11 is located in the accommodating space of the explosion-proof casing 1 of the detection device, and the two ports are located outside the explosion-proof casing 1 of the detection device; the gas sampler 11 is connected to the connecting accessory 23 through the sampling hose 22 for sampling the leaked gas.

[0049] Furthermore, the gas sampler 11 includes an inlet filter screen 111, a gas sampling point 112, a large-flow gas sampling pump 113 and a first gas outlet 114; wherein, the inlet filter screen 111 is arranged at one end of the gas sampler 11 and is connected to the large-flow gas sampling pump 113 through a pipeline; the gas sampling point 112 is arranged on the side wall of the gas sampler 11; and the first gas outlet 114 is arranged at the other end of the gas sampler 11.

[0050] The data measurement module 102 includes: a circuit board 12, a first solenoid valve 121, a second solenoid valve 123, a first TDLAS sensor 124, a second TDLAS sensor 125 and a second gas outlet 126; wherein, the first solenoid valve 121 and the second solenoid valve 123 are both welded on the circuit board 12, and the first solenoid valve 121 is connected to the background gas inlet 127, the gas sampling point 112 and the micro gas sampling pump 122 through pipelines; the second solenoid valve 123 is connected to the micro gas sampling pump 122, the first TDLAS sensor 124 and the second TDLAS sensor 125 through pipelines; the first TDLAS sensor 124 and the second TDLAS sensor 125 are both connected to the second gas outlet 126 through pipelines.

[0051] The display module 103 includes a handheld terminal 2 and a menu button 21 ; wherein the menu button 21 is disposed on the handheld terminal 2 .

[0052] The power supply module 104 includes a rechargeable battery 3 and a plurality of connecting wires; wherein the rechargeable battery 3 is directly connected to the explosion-proof housing 1 of the detection device via the connecting wires.

[0053] The safety module 105 includes an explosion-proof housing 1 of a detection device and a grounding wire 4 ; wherein the grounding wire 4 is directly connected to the explosion-proof housing 1 of the detection device.

[0054] Figure 2 This is a schematic diagram of the overall structure of a methane and VOCs collaborative detection system based on TDLAS according to an embodiment of the present invention; Figure 3 FIG. 1 is a schematic diagram of a local structure of a methane and VOCs collaborative detection system based on TDLAS according to an embodiment of the present invention; Figure 2-3 As shown, the detection system includes: an explosion-proof housing 1 of a detection device, a handheld terminal 2, a rechargeable battery 3, and a grounding wire 4. The explosion-proof housing 1 of the detection device partially wraps a gas sampler 11, and the gas sampler 11 includes an inlet filter screen 111, a gas sampling point 112, a large-flow gas sampling pump 113 and a first gas outlet 114; the gas sampling point 112 is connected to a circuit board 12, and a first solenoid valve 121, a second solenoid valve 123 and other electronic components are installed on the circuit board 12. Through circuit control and the suction of a micro gas sampling pump 122, the gas to be tested is passed into the second solenoid valve 123, and the gas after testing is discharged through the second gas outlet 126. The inlet filter screen 111 is connected to the sampling hose 22, and the sampling hose 22 is connected to the connecting accessory 23 according to different measuring positions; the handheld terminal 2 is connected to other modules of the detection system by wireless means, and a menu button 21 is provided on the handheld terminal. The rechargeable battery 3 is directly connected to the explosion-proof housing 1 of the detection device, and the grounding wire 4 is directly connected to the explosion-proof housing 1 of the detection device.

[0055] Based on the above detection system, the present invention also discloses a TDLAS-based methane and VOCs collaborative detection method, the method comprising the following steps:

[0056] Step (1), after the safety module 105 is grounded, the sampling module 101 is started to sample the background gas; then the data measurement module 102 is started to measure the relevant data of the background gas; finally, the display module 103 displays the concentration of methane and VOCs in the background gas;

[0057] Step (2), using the detection system to inspect the dynamic and static sealing points of the enterprise equipment, or using a gas imaging infrared camera to observe gas leakage at oil and gas field stations;

[0058] Step (3), where a gas leak is found, select a suitable connection accessory 23 according to the shape and size of the component, connect the connection accessory 23 to the location of the leak source, and use the detection system to collect all leaked gases;

[0059] Step (4), start the sampling module 101 to sample the leaked gas; then start the data measurement module 102 to measure the relevant data of the leaked gas; finally, the display module 103 displays the concentration of methane and VOCs in the leaked gas.

[0060] Furthermore, the method of using the detection system to test the methane and VOCs emission concentrations at a leakage point in this embodiment specifically includes the following steps:

[0061] Step (1), after grounding the grounding wire 4 of the safety module 105, turn on the menu button 21 on the handheld terminal 2, start the background gas measurement, and in a clean atmospheric environment, start the micro gas sampling pump 122 to measure the background gas concentration; the background gas enters through the background gas inlet 127, flows through the first solenoid valve 121, starts the micro gas sampling pump 122 to pump gas, starts the second solenoid valve 123, and divides the gas into two paths, one path enters the first TDLAS sensor 124 for methane measurement, and the other path enters the second TDLAS sensor 125 for VOCs measurement. After the methane and VOCs concentrations in the background gas are measured by the first TDLAS sensor 124 and the second TDLAS sensor 125 respectively, they are displayed on the handheld terminal 2, and the gas is discharged through the second gas outlet 126.

[0062] Step (2), using the detection system to patrol and inspect the dynamic and static sealing points of the enterprise equipment, including pumps, compressors, agitators, valves, pressure relief equipment sampling connection systems, open valves or open pipelines, flanges, connectors and other systems, and can also be used in conjunction with a gas imaging infrared camera to observe gas leaks at oil and gas field stations.

[0063] Step (3), where a gas leak is found, use a TDLAS-based methane and VOCs collaborative detection system; select a suitable connection accessory 23 according to the shape and size of the component to collect all the leaked gases, complete the connection between the inlet filter screen 111, the sampling hose 22 and the connection accessory 23, and connect the connection accessory 23 to the location of the leak source.

[0064] Step (4), turn on the menu button 21 on the handheld terminal 2, after all components display normally, start the large-flow gas sampling pump 113, the leaked methane and VOCs gas enters the gas sampler 11 through the inlet filter screen 111, passes through the gas sampling point 112, flows through the first solenoid valve 121, starts the micro gas sampling pump 122 to extract gas, starts the second solenoid valve 123, and divides the gas into two paths, one path enters the first TDLAS sensor 124 for methane measurement, and the other path enters the second TDLAS sensor 125 for VOCs measurement. The final reading is displayed on the handheld terminal 2, and the gas that has not entered the gas sampling point 112 is discharged through the first gas outlet 114.

[0065] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A TDLAS-based methane and VOCs collaborative detection system, characterized in that: The detection system comprises: a sampling module (101), a data measurement module (102) and a display module (103); the sampling module (101) is connected to the data measurement module (102) via a pipeline, and the display module (103) performs data exchange with the sampling module (101) and the data measurement module (102) via a wireless method; wherein: The sampling module (101) is used to sample background gas and leaked gas; The data measurement module (102) is used to measure the sampled background gas and leakage gas; The display module (103) is used to display the concentrations of background gas and leaked gas.

2. According to claim 1, a TDLAS-based methane and VOCs collaborative detection system is characterized in that: The sampling module (101) comprises: a micro gas sampling pump (122), a background gas inlet (127), a gas sampler (11), a sampling hose (22) and a connecting accessory (23); wherein: The background gas inlet (127) is arranged on the explosion-proof housing (1) of the detection device, and is connected to the micro gas sampling pump (122) through a pipeline, and is used for sampling the background gas; The middle part of the gas sampler (11) is located in the accommodating space of the explosion-proof housing (1) of the detection device, and the two ports are located outside the explosion-proof housing (1) of the detection device. The gas sampler (11) is connected to the connecting accessory (23) through a sampling hose (22) for sampling leaked gas.

3. According to claim 2, a TDLAS-based methane and VOCs collaborative detection system is characterized in that: The gas sampler (11) comprises an inlet filter screen (111), a gas sampling point (112), a large-flow gas sampling pump (113) and a first gas outlet (114); wherein, The inlet filter screen (111) is arranged at one end of the gas sampler (11) and is connected to a large-flow gas sampling pump (113) through a pipeline; The gas sampling point (112) is arranged on the side wall of the gas sampler (11); The first gas outlet (114) is arranged at the other end of the gas sampler (11).

4. A TDLAS-based methane and VOCs collaborative detection system according to claim 1 or 2, characterized in that: The data measurement module (102) comprises: a circuit board (12), a first solenoid valve (121), a second solenoid valve (123), a first TDLAS sensor (124), a second TDLAS sensor (125) and a second gas outlet (126); wherein: The first solenoid valve (121) and the second solenoid valve (123) are both welded on the circuit board (12); the first solenoid valve (121) is connected to the background gas inlet (127), the gas sampling point (112) and the micro gas sampling pump (122) through pipelines; the second solenoid valve (123) is connected to the micro gas sampling pump (122), the first TDLAS sensor (124) and the second TDLAS sensor (125) through pipelines; the first TDLAS sensor (124) and the second TDLAS sensor (125) are both connected to the second gas outlet (126) through pipelines.

5. The TDLAS-based methane and VOCs collaborative detection system according to claim 2, characterized in that: The display module (103) comprises a handheld terminal (2) and a menu button (21); wherein: The menu button (21) is arranged on the handheld terminal (2).

6. The TDLAS-based methane and VOCs collaborative detection system according to claim 1, characterized in that: The detection system further comprises: a power supply module (104) and a safety module (105); the power supply module (104) and the safety module (105) are connected; wherein, The power supply module (104) is used to supply power to the sampling module (101), the data measurement module (102) and the display module (103); The safety module (105) is used to ensure the safety of the power supply module (104).

7. The TDLAS-based methane and VOCs collaborative detection system according to claim 6, characterized in that: The power supply module (104) comprises a rechargeable battery (3) and a plurality of connecting wires; wherein the rechargeable battery (3) is connected to the explosion-proof housing (1) of the detection device via the connecting wires.

8. The TDLAS-based methane and VOCs collaborative detection system according to claim 6, characterized in that: The safety module (105) comprises a detection device explosion-proof housing (1) and a grounding wire (4); wherein the grounding wire (4) is connected to the detection device explosion-proof housing (1).

9. A TDLAS-based method for collaborative detection of methane and VOCs, the method using the system of claims 1-8, characterized in that: The method comprises the following steps: Step (1), after the safety module (105) is grounded, the sampling module (101) is started to sample the background gas; then the data measurement module (102) is started to measure the background gas; finally, the display module (103) displays the concentration of methane and VOCs in the background gas; Step (2), using the detection system to inspect the dynamic and static sealing points of the enterprise equipment, or using a gas imaging infrared camera to observe gas leakage at oil and gas field stations; Step (3), where a gas leak is found, a suitable connection accessory (23) is selected according to the shape and size of the component, and the connection accessory (23) is connected to the location of the leak source, and all leaked gases are collected using the detection system; Step (4), start the sampling module (101) to sample the leaked gas; then start the data measurement module (102) to measure the leaked gas; finally, the display module (103) displays the concentrations of methane and VOCs in the leaked gas.

10. A TDLAS-based methane and VOCs collaborative detection method according to claim 9, characterized in that: The dynamic and static sealing points include: pumps, compressors, agitators, valves, pressure relief equipment sampling connection systems, open valves, open pipelines, flanges and connectors.

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