Gas detection control system and detection method

Abstract

The invention discloses a gas detection control system and a detection method.The control system comprises a controller, the controller is in communication connection with an audible and visual alarm, a laser gas detector and a sampling unit, the laser gas detector is connected with a detection cavity, and the detection cavity is connected with one end of a gas conveying pipeline and one end of an exhaust pipeline; an exhaust port is formed in the other end of the exhaust pipeline, and the other end of the gas conveying pipeline is connected with the sampling unit. The detection method adopts a half-division exclusion method for detection. According to the method, few detection devices are adopted, and calibration and maintenance are easy.

Description

Technical Field

[0001] This invention belongs to the field of gas monitoring technology, specifically relating to a gas detection and control system, and also to a method for detecting gas using the aforementioned gas detection and control system. Background Technology

[0002] The safe and stable production of oil and gas fields is of paramount importance. Combustible and toxic gas detection (hereinafter referred to as gas detection) at oil and gas field stations mainly employs fixed gas detectors to detect the concentration of leaked gases in oil and gas sites. The installation location must be selected based on factors such as the gas's physicochemical properties, release source characteristics, production site layout, geographical conditions, environmental climate, and operational inspection routes, ensuring the gas easily accumulates and is convenient for maintenance. In outdoor open-air or open-plan plant buildings, the protection radius for combustible gas detectors is 10m, and for toxic gas detectors, it is 4m. In enclosed or poorly ventilated semi-open plant buildings, the protection radius for combustible gas detectors is 5m, and for toxic gas detectors, it is 2m. Since gases lighter than air tend to accumulate at the highest point within the plant building, a gas detector must also be installed at the highest point of the plant building.

[0003] In summary, using fixed gas detectors for gas detection requires deploying a large number of detectors at high locations, which makes subsequent calibration and maintenance difficult. Summary of the Invention

[0004] The purpose of this invention is to provide a gas detection and control system that uses fewer detection devices, has a low installation position, and is easy to calibrate and maintain.

[0005] Another object of the present invention is to provide a gas detection method.

[0006] The technical solution adopted in this invention is a gas detection and control system, including a controller. The controller is communicatively connected to an audible and visual alarm, a laser gas detector, and a sampling unit. The laser gas detector is connected to a detection chamber. The detection chamber is connected to one end of a gas supply pipeline and an exhaust pipeline. An exhaust port is provided at the other end of the exhaust pipeline. The other end of the gas supply pipeline is connected to the sampling unit.

[0007] The invention is further characterized in that,

[0008] The sampling unit includes at least one main pipeline. One end of each main pipeline is connected to the end of the gas supply pipeline away from the detection chamber. The other end of each main pipeline is connected to at least one branch pipeline. Each branch pipeline is provided with a sampling port at the end away from the main pipeline. Each main pipeline is provided with a solenoid valve, and each solenoid valve is communicatively connected to the controller.

[0009] Each main pipeline is equipped with an air pump, and each air pump is connected to the controller.

[0010] The solenoid valve, air pump, detection chamber, laser gas detector, and controller are all housed inside the explosion-proof junction box, while the audible and visual alarm is located on the outer wall of the explosion-proof junction box.

[0011] Electrical interfaces are provided on the side wall of the explosion-proof junction box.

[0012] Each sampling port is equipped with a sieve.

[0013] Another technical solution adopted in this invention is a gas detection method, which uses the above-mentioned gas detection and control system and is implemented according to the following steps:

[0014] In the initial state, the controller opens all solenoid valves and the vacuum pump, and all sampling ports sample the gas. The collected gas enters the detection chamber, and the controller controls the laser gas detector to detect the concentration of the gas collected in the detection chamber. When the detected gas concentration exceeds the comprehensive gas concentration alarm limit, the controller uses a semi-exclusion method to detect the concentration of the gas collected in the detection chamber. When the detected gas concentration does not exceed the comprehensive gas concentration alarm limit, it indicates that there is no gas leak.

[0015] The invention is further characterized in that,

[0016] The controller uses a semi-exclusion method to detect the concentration of gas collected in the detection chamber. The specific process is as follows:

[0017] When the number of branch pipes on each main pipe is 1:

[0018] If the detected gas concentration exceeds the overall gas concentration alarm limit in the initial state, the controller closes 50% of the solenoid valves and simultaneously shuts down the corresponding pumps. The remaining 50% of the sampling ports continue to collect gas into the detection chamber, where the laser gas detector monitors the gas concentration. If the detected gas concentration still exceeds the overall gas concentration alarm limit, the above process is repeated. If the detected gas concentration does not exceed the overall gas concentration alarm limit, the controller opens the last closed solenoid valve and pump, while simultaneously shutting down all other solenoid valves and pumps. The laser gas detector then monitors the gas concentration.

[0019] When the remaining sampling port can sample normally, if the detected gas concentration still exceeds the comprehensive gas concentration alarm limit, the controller will activate the audible and visual alarm and display the area where the gas concentration exceeds the limit; if the detected gas concentration does not exceed the comprehensive gas concentration alarm limit, all solenoid valves and air pumps will be opened to continue the detection.

[0020] The controller uses a semi-exclusion method to detect the concentration of gas collected in the detection chamber. The specific process is as follows:

[0021] When the number of branch pipes on a part of the main road is 1, the number of branch pipes on another part of the main road is several, or the number of branch pipes on each main road is several, the main roads with the same number of branch pipes are grouped according to the number of branch pipes on each main road.

[0022] If the detected gas concentration exceeds the overall gas concentration alarm limit in the initial state, the controller will open all solenoid valves and vacuum pumps on one group of main pipelines, and close all solenoid valves and vacuum pumps on the remaining groups of main pipelines. If the detected gas concentration exceeds the overall gas concentration alarm limit, the detection process for that group of branch pipelines will be performed according to the detection process when the number of branch pipelines on each main pipeline is 1. All solenoid valves and vacuum pumps on the remaining groups of main pipelines will remain closed. After the entire group of main pipelines has been processed, the above operation will be performed on the next group of main pipelines, until all groups of main pipelines have been processed.

[0023] The expression for the comprehensive gas concentration alarm limit is:

[0024]

[0025] In the formula, OLT is the comprehensive gas concentration alarm limit, SAV is the alarm value specified in the standard, and N is the number of open sampling ports.

[0026] The beneficial effects of this invention are as follows: The gas detection and control system of this invention adopts active pump suction cyclic sampling detection. By setting up multiple remote gas sampling ports, it actively and remotely collects possible leaked gas, realizing multi-release source and ultra-high point gas collection and monitoring. It reduces the number of gas detectors and the laser gas detector is installed at a low position, shortening the detection alarm time, reducing the workload and difficulty of construction, calibration and maintenance, effectively reducing the safety risks to personnel during inspection and calibration, and improving work efficiency. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the gas detection and control system of the present invention;

[0028] Figure 2 This is a flowchart of Embodiment 4 of the present invention.

[0029] In the diagram, 1. Main pipe, 2. Electrical interface, 3. Explosion-proof junction box, 4. Audible and visual alarm, 5. Laser gas detector, 6. Controller, 7. Solenoid valve, 8. Air pump, 9. Exhaust port, 10. Sampling port, 11. Detection chamber, 12. Branch pipe, 13. Exhaust pipe, 14. Gas transmission pipe. Detailed Implementation

[0030] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0031] Example 1

[0032] The gas detection and control system of the present invention includes an explosion-proof junction box 3, inside which is a controller 6. The controller 6 is connected to an audible and visual alarm 4, a laser gas detector 5, and a sampling unit. The audible and visual alarm 4 is used to issue an alarm, facilitating timely handling by personnel. The laser gas detector 5 is used to detect the concentration of the collected gas. The sampling unit is used to collect gas from various locations. The laser gas detector 5 is connected to a detection chamber 11, which is connected to one end of a gas supply pipeline 14 and an exhaust pipeline 13. The other end of the exhaust pipeline 13 is provided with an exhaust port 9. The other end of the gas supply pipeline 14 is connected to the sampling unit. The laser gas detector 5 and the detection chamber 11 are both located inside the explosion-proof junction box 3. The audible and visual alarm 4 is located on the outer wall of the explosion-proof junction box 3. An electrical interface 2 is provided on the side wall of the explosion-proof junction box 3, which is connected to the controller 6. The controller 6 is connected to a 220VAC power supply for powering the controller 6.

[0033] Furthermore, the explosion-proof junction box 3 is internally divided into three spaces by a partition. The controller 6 is located in the first space. The laser gas detector 5, the detection chamber 11, one end of the gas supply pipe 14, and one end of the exhaust pipe 13 are all located in the second space, with the other end of the exhaust pipe 13 extending out of the side wall of the explosion-proof junction box 3. One end of the sampling unit and the other end of the gas supply pipe 14 are located in the third space, with the other end of the sampling unit extending out of the side wall of the explosion-proof junction box 3. The controller 6 modulates the driving current of the tunable semiconductor laser in the laser gas detector 5, causing the laser to emit a laser of a specific wavelength. The laser passes through the gas being measured in the detection chamber 11. After the gas being measured absorbs the laser of the specific wavelength, the concentration of the gas being measured is determined by measuring the attenuation of the laser. The controller 6 is also used to acquire the gas concentration data detected by the laser gas detector 5 and compare it with the comprehensive gas concentration alarm limit. Simultaneously, based on the comparison result, the controller controls the audible and visual alarm 4 to sound an alarm.

[0034] Example 2

[0035] Based on Embodiment 1, the sampling unit includes at least one main pipeline 1. One end of each main pipeline 1 is connected to the end of the gas supply pipeline 14 away from the detection chamber 11. The other end of each main pipeline 1 is connected to at least one branch pipeline 12. Each branch pipeline 12 is provided with a sampling port 10 at the end away from the main pipeline 1. Each sampling port 10 is provided with a screen to prevent mosquitoes from entering and clogging the pipeline. Each branch pipeline 12 is vertically arranged and each sampling port 10 is downward-facing to prevent rainwater from entering the branch pipeline 12. Each main pipeline 1 is provided with a solenoid valve 7 and a vacuum pump 8. The solenoid valve 7 is used to control the opening and closing of the main pipeline 1, and the vacuum pump 8 is used to draw gas into the detection chamber 11. The solenoid valve 7 and the vacuum pump 8 are both located in the third space of the explosion-proof junction box 3. The solenoid valve 7 and the vacuum pump 8 are both communicatively connected to the controller 6. The controller 6 is used to control the opening and closing of the solenoid valve 7 and the vacuum pump 8.

[0036] The gas detection and control system of the present invention is deployed as follows: according to the equipment layout of the oil and gas field station, an explosion-proof junction box 3 is set up at a certain point, and the main pipeline 1 is laid to each detection area. Branch pipelines are laid in each detection area to the sampling point of the detection area. One device area or equipment room is divided into one detection area, which is one sampling point.

[0037] Example 3

[0038] The gas detection method of the present invention, employing the aforementioned gas detection and control system, is implemented specifically according to the following steps:

[0039] In the initial state, the controller 6 controls all solenoid valves 7 and the air pump 8 to open, so all sampling ports 10 will sample. The collected gas enters the detection chamber 11. The controller 6 controls the laser gas detector 5 to detect the gas concentration collected in the detection chamber 11. When the gas concentration exceeds the comprehensive gas concentration alarm limit, the controller 6 uses a half-exclusion method to detect the gas concentration collected in the detection chamber 11. When the gas concentration does not exceed the comprehensive gas concentration alarm limit, it indicates that there is no gas leakage.

[0040] The expression for the comprehensive gas concentration alarm limit is:

[0041]

[0042] In the formula, OLT is the comprehensive gas concentration alarm limit, SAV is the alarm value specified in the standard, and N is the number of open sampling ports. If each main pipeline 1 is equipped with several branch pipelines 12, then the number of sampling ports is the number on a single main pipeline 1. If each main pipeline 1 is equipped with one branch pipeline 12, then the number of sampling ports is the number of open main pipelines 1.

[0043] The controller 6 uses a semi-exclusion method to detect the concentration of gas collected in the detection chamber 11. The specific process includes two cases: the first case is that the number of branch pipes 12 on each main pipe 1 is 1, that is, multiple pipes with a single sampling port; the second case is that the number of branch pipes 12 on some main pipes 1 is 1, and the number of branch pipes 12 on other main pipes 1 is several, or the number of branch pipes 12 on each main pipe 1 is several, that is, multiple pipes with a combined sampling port.

[0044] (1) When the number of branch pipes 12 on each main pipe 1 is 1:

[0045] If the detected gas concentration exceeds the overall gas concentration alarm limit in the initial state, the controller 6 controls 50% of the solenoid valves 7 to close, and simultaneously controls the corresponding vacuum pump 8 to close. Then, the remaining 50% of the sampling ports 10 continue to collect gas into the detection chamber 11, and the laser gas detector 5 detects the gas concentration. If the detected gas concentration still exceeds the overall gas concentration alarm limit, the above process is repeated. If the detected gas concentration does not exceed the overall gas concentration alarm limit, the controller 6 controls the last closed solenoid valve 7 and vacuum pump 8 to open, and simultaneously closes all other solenoid valves 7 and vacuum pump 8. The laser gas detector 5 then detects the gas concentration.

[0046] When the remaining sampling port 10 can sample normally, if the gas concentration is still detected to exceed the comprehensive gas concentration alarm limit, the controller 6 will activate the audible and visual alarm 4 to sound an alarm and display the area where the gas concentration exceeds the limit; if the gas concentration is not detected to exceed the comprehensive gas concentration alarm limit, all solenoid valves 7 and the air pump 8 will be opened to continue the detection.

[0047] (2) When the number of branch pipes 12 on a part of the main road 1 is 1, the number of branch pipes 12 on another part of the main road 1 is several, or the number of branch pipes 12 on each main road 1 is several, group them according to the number of branch pipes 12 on each main road 1, and group the main roads 1 with the same number of branch pipes 12 into one group.

[0048] If the detected gas concentration exceeds the overall gas concentration alarm limit in the initial state, the controller 6 controls all solenoid valves 7 and vacuum pumps 8 on one group of main pipelines 1 to open, and all solenoid valves 7 and vacuum pumps 8 on the remaining groups of main pipelines 1 to close. If the detected gas concentration exceeds the overall gas concentration alarm limit, the detection process of the group of main pipelines 1 is executed according to the first case (when the number of branch pipes 12 on each main pipeline 1 is 1). All solenoid valves 7 and vacuum pumps 8 on the remaining groups of main pipelines 1 remain closed. After the group of main pipelines 1 has been fully executed, the above operation is performed on the next group of main pipelines 1 until all groups of main pipelines 1 have been fully executed.

[0049] Example 4

[0050] Taking a scenario with four pipelines and combustible gas as the detection medium as an example, the controller is laid to the field device area... Main pipelines are set up separately in the plant area. Branch pipelines, communication and power cables are connected via electrical interfaces, and the sampled gas collected on-site is discharged through exhaust ports.

[0051] When the system is powered on, controller 6 controls the opening of solenoid valves 7 (1# to 4#) and pumps 8 (1# to 4#). The sample gas is transported from the site to the detection chamber connected to the laser gas detector via branch pipelines, main pipelines, and gas delivery pipelines. Controller 6 modulates the drive current to enable the tunable semiconductor laser of the laser gas detector to emit laser light of a specific wavelength. The laser light passes through the gas to be measured in the detection chamber. After the gas to be measured absorbs the laser light of the specific wavelength, the concentration of the gas to be measured is determined by measuring the attenuation of the laser light.

[0052] When the gas leakage concentration in the chamber exceeds the limit, the intelligent controller shuts down solenoid valves 7 (3# and 4#) and the air pump 8, and the gas detector detects the gas in pipelines 1# and 2#. When the concentration of combustible gas leaking in the detection chamber exceeds the alarm limit for the comprehensive gas concentration, controller 6 closes solenoid valve 7 (2#) and pump 8. The laser gas detector detects the gas in pipeline 1. If the concentration of combustible gas leaking in the chamber exceeds the alarm limit for the comprehensive gas concentration, then there is a combustible gas leak in the corresponding device area of ​​pipeline 1, and the system issues an audible and visual alarm, opening solenoid valves 7 (2#, 3#, and 4#) and pump 8. If the concentration of combustible gas in the sample gas from pipeline 1 does not exceed the alarm limit for the comprehensive gas concentration, controller 6 closes solenoid valve 7 (1#) and pump 8, and opens solenoid valve 7 (2#) and pump 8. The laser gas detector detects the gas in pipeline 2. If the concentration of combustible gas leaking in the detection chamber exceeds the alarm limit for the comprehensive gas concentration, then there is a combustible gas leak in the corresponding device area of ​​pipeline 2, and the system issues an audible and visual alarm, opening solenoid valves 7 (1#, 3#, and 4#) and pump 8. If the concentration of combustible gas coming from pipeline #2 does not exceed the alarm limit for overall gas concentration, controller #6 will activate solenoid valves #1, #3, and #4, and the air pump #8.

[0053] If the concentration of combustible gas in the gas coming from pipelines 1 and 2 does not exceed the comprehensive gas concentration alarm limit after controller 6 closes solenoid valves 7 and 4 and pump 8, then controller 6 closes solenoid valves 7 and 4 and pump 8 and opens solenoid valves 7 and 4 and pump 8. When the concentration of combustible gas leaking in the detection chamber exceeds the comprehensive gas concentration alarm limit, controller 6 closes solenoid valve 7 (4#) and pump 8. The laser gas detector then detects the gas in pipeline 3. If the concentration exceeds the comprehensive gas concentration alarm limit, a combustible gas leak is detected in the corresponding area of ​​pipeline 3, and the system issues an audible and visual alarm. If the concentration of combustible gas in the sample gas from pipeline 3 does not exceed the comprehensive gas concentration alarm limit, controller 6 closes solenoid valve 7 (3#) and pump 8, and opens solenoid valve 7 (4#) and pump 8. The laser gas detector 5 then detects the gas in pipeline 4. If the concentration exceeds the comprehensive gas concentration alarm limit, a combustible gas leak is detected in the corresponding area of ​​pipeline 4, and the system issues an audible and visual alarm. If the concentration of combustible gas in the sample gas from pipeline 4 does not exceed the comprehensive gas concentration alarm limit, controller 6 opens all solenoid valves 7 and pump 8.

Claims

1. A gas detection control system, characterized by, Including controller (1), the controller (6) is connected with sound and light alarm (4), laser gas detector (5) respectively, sampling unit, laser gas detector (5) is connected with detection chamber (11), detection chamber (11) is connected with gas pipeline (14), exhaust pipeline (13) one end respectively, the other end of exhaust pipeline (13) is provided with exhaust port (9), the other end of gas pipeline (14) is connected with sampling unit.

2. The gas detection control system of claim 1, wherein, The sampling unit includes at least one main pipeline (1), one end of each main pipeline (1) is connected with the end of the gas pipeline (14) away from the detection chamber (11), the other end of each main pipeline (1) is connected with at least one branch pipeline (12), the end of each branch pipeline (12) away from the main pipeline (1) is provided with a sampling port (10), and each main pipeline (1) is provided with an electromagnetic valve (7), and each electromagnetic valve (7) is connected with the controller (6).

3. The gas detection control system of claim 2, wherein, Each main pipeline (1) is provided with an air pump (8), and each air pump (9) is connected with the controller (6).

4. The gas detection control system of claim 3, wherein, The electromagnetic valve (7), air pump (8), detection chamber (11), laser gas detector (5), controller (6) are arranged in the explosion-proof junction box (3), and the sound and light alarm (4) is arranged on the outer wall of the explosion-proof junction box (3).

5. The gas detection control system of claim 4, wherein, The side wall of the explosion-proof junction box (3) is provided with an electrical interface (2).

6. The gas detection control system of claim 2, wherein, Each sampling port (10) is provided with a screen.

7. A method of gas detection, characterised in that, The gas detection control system of any one of claims 1-6 is implemented according to the following steps: In the initial state, the controller (6) controls all electromagnetic valves (7) and air pumps (8) to open, then all sampling ports (10) sample, and the collected gas enters the detection chamber (11), the controller (6) controls the laser gas detector (5) to detect the concentration of the gas collected in the detection chamber (11), when the concentration of the gas is detected to exceed the comprehensive gas concentration alarm limit, the controller (6) uses the half exclusion method to detect the concentration of the gas collected in the detection chamber (11), when the concentration of the gas is detected to not exceed the comprehensive gas concentration alarm limit, it indicates that there is no gas leakage.

8. The gas detection method of claim 7, wherein, The specific process of the controller (6) using the half exclusion method to detect the concentration of the gas collected in the detection chamber (11) is as follows: When the number of branch pipelines (12) on each main pipeline (1) is 1: If the detected gas concentration exceeds the comprehensive gas concentration alarm limit in the initial state, the controller (6) controls 50% of the electromagnetic valves (7) to close, and controls the corresponding gas suction pump (8) of the closed electromagnetic valve (7) to close, then the remaining 50% of the sampling port (10) continues to collect gas into the detection chamber (11), and the laser gas detector (5) detects the gas concentration, and when the detected gas concentration still exceeds the comprehensive gas concentration alarm limit, the above process is repeatedly executed; when the detected gas concentration does not exceed the comprehensive gas concentration alarm limit, the controller (6) controls the last closed electromagnetic valve (7) and the gas suction pump (8) to open, while closing all the remaining electromagnetic valves (7) and gas suction pumps (8), and the laser gas detector (5) detects the gas concentration; When there is only one sampling port (10) that can normally sample, if the detected gas concentration still exceeds the comprehensive gas concentration alarm limit, the controller (6) starts the audible and visual alarm (4) to alarm and displays the area where the gas concentration exceeds the limit; if the detected gas concentration does not exceed the comprehensive gas concentration alarm limit, all electromagnetic valves (7) and gas suction pumps (8) are opened for continuous detection.

9. The gas detection method of claim 8, wherein, The specific process of the controller (6) using the half-elimination method to detect the concentration of the gas collected into the detection chamber (11) is as follows: When the number of branch pipes (12) on one part of the main pipe (1) is 1, and the number of branch pipes (12) on the other part of the main pipe (1) is several, or the number of branch pipes (12) on each main pipe (1) is several, the main pipes (1) with the same number of branch pipes (12) are grouped according to the number of branch pipes (12) on each main pipe (1). If the detected gas concentration exceeds the comprehensive gas concentration alarm limit in the initial state, the controller (6) controls all electromagnetic valves (7) and gas suction pumps (8) on one group of main pipes (1) to open, and all electromagnetic valves (7) and gas suction pumps (8) on the remaining groups of main pipes (1) to close, if the detected gas concentration exceeds the comprehensive gas concentration alarm limit, the detection process of the group of branch pipes (1) is executed according to the detection process when the number of branch pipes (12) on each main pipe (1) is 1, and the remaining groups of main pipes (1) remain in the closed state, and after the group of main pipes (1) is executed completely, the next group of main pipes (1) is executed according to the above operation, until all groups of main pipes (1) are executed completely.

10. The gas detection method of claim 9, wherein, The expression of the comprehensive gas concentration alarm limit is: In the formula, OLT is the comprehensive gas concentration alarm limit, SAV is the alarm value specified in the specification, and N is the number of open sampling ports.

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