Variable-frequency gas extraction regulation and control system

Abstract

The utility model discloses a variable-frequency gas extraction regulation and control system which comprises an extraction main pipe, a plurality of extraction branch pipes, a methane concentration sensor, an electric regulating valve, a main pipe pressure sensor, a variable-frequency water ring vacuum pump, a gas-water separator, a pressure type liquid level sensor, a drainage electromagnetic valve and an electric control device. The gas concentration of each extraction branch pipe is detected in real time through a methane concentration sensor, and when the concentration is lower than a preset threshold value, the electric control valve of the corresponding branch pipe is closed; a main pipe pressure sensor monitors system pressure and dynamically adjusts the rotating speed of the variable-frequency water ring vacuum pump to meet the load requirement; water level monitoring and drainage of the gas-water separator are achieved through the pressure type liquid level sensor and the drainage electromagnetic valve. The water circulation system integrates a frequency conversion fan and a temperature sensor, and the cooling efficiency of the cooling tower is adjusted as needed. According to the utility model, the low-concentration branch pipe can be closed timely, and invalid extraction is avoided; the frequency conversion technology dynamically matches the load to reduce energy consumption; timely drainage and temperature control guarantee equipment stability; branch pipe pressure balance control reduces air mixing, and the service life of equipment is prolonged.

Description

Technical Field

[0001] This utility model relates to the field of coal mine gas extraction, and in particular to energy-saving technology and centralized control technology in gas extraction. Background Technology

[0002] Current coal mine gas extraction systems generally operate in power frequency mode, which has the following key drawbacks:

[0003] 1. High energy consumption and low efficiency:

[0004] Water ring vacuum pumps operate at a fixed speed and their power cannot be adjusted, resulting in significant energy waste during low-concentration gas extraction.

[0005] 2. Control relies on manual on-site inspections:

[0006] Traditionally, manual on-site inspections are required to shut down low-concentration branch pipes (e.g., concentration <0.5%), resulting in delayed response and ineffective sampling.

[0007] The drain solenoid valve of the gas-liquid separator needs to be operated manually, and failure to control the liquid level in a timely manner can easily lead to equipment damage.

[0008] 3. The temperature control of the water ring vacuum pump subsystem is unstable, resulting in high energy consumption.

[0009] When the cooling tower fan operates at a constant speed, it cannot match the actual heat load of the working fluid, often causing the working fluid temperature to exceed the optimal range of 35℃–45℃, thus reducing the sealing efficiency of the vacuum pump. High actual heat dissipation demand can easily lead to excessively high coolant (water) temperatures, while low actual heat dissipation demand can easily lead to excessively low coolant (water) temperatures, wasting energy.

[0010] The aforementioned defects severely restrict the achievement of the goal of "extracting all coal mine gas and utilizing it efficiently." Especially under the background of the "dual carbon" strategy, there is an urgent need for an innovative solution that integrates variable frequency speed regulation, multi-sensor closed-loop control, and remote centralized control to simultaneously solve the problems of energy consumption, efficiency, and equipment stability. Utility Model Content

[0011] The purpose of this invention is to address the problems in the existing technology by providing a variable frequency gas extraction control system that eliminates the need for manual on-site inspections, can promptly close ineffective boreholes, avoids wasting energy through ineffective extraction, concentrates the extraction negative pressure on effective boreholes, and improves extraction efficiency.

[0012] To achieve the above objectives, the variable frequency gas extraction and control system of this utility model includes an extraction main pipe, which extends longitudinally and is connected to multiple extraction branch pipes; each extraction branch pipe is connected to a gas extraction hole in a one-to-one correspondence for transporting gas; each extraction branch pipe is connected to a methane concentration sensor and an electric regulating valve, which is used to control the gas flow rate.

[0013] A main pipe pressure sensor is installed on the extraction main pipe; the extraction main pipe is connected to the inlet of the variable frequency water ring vacuum pump, which is used to generate negative pressure to extract gas; the exhaust port of the variable frequency water ring vacuum pump is connected to the storage container or gas-using unit through the gas delivery pipeline; the methane concentration sensor, electric regulating valve and main pipe pressure sensor are all connected to the same electronic control device through the circuit, and the electronic control device has a concentration threshold P1 pre-stored in it.

[0014] When the methane concentration detected by the methane concentration sensor is lower than P1, the corresponding electric regulating valve is closed.

[0015] The electrical control device is connected to a computer, which has a display screen; the electrical control device, computer, and display screen are located in the monitoring room.

[0016] Each extraction branch pipe is connected to a branch pipe pressure sensor, which is connected to the electrical control device via wiring.

[0017] The exhaust port of the variable frequency water ring vacuum pump is connected to a gas-liquid separator. The top of the gas-liquid separator is connected to the gas delivery pipeline and then connected to a storage container or a gas-using unit through the gas delivery pipeline.

[0018] A pressure-type liquid level sensor is installed at the bottom of the gas-liquid separator, and a drain solenoid valve is connected downwards to the gas-liquid separator; the drain solenoid valve and the pressure-type liquid level sensor are respectively connected to the electronic control device through wiring.

[0019] The variable frequency water ring vacuum pump is connected to a water circulation system, which ensures the pump's sealing. The water circulation system includes an upper water tank, a lower water tank, and a cooling tower. A drain solenoid valve is connected to a drain pipe, which leads to the lower water tank. A water pump is connected to the lower water tank, and the pump's outlet pipe is connected to the upper water tank. The upper water tank is higher than the cooling tower and is connected to the cooling tower's input end via a pipeline. The cooling tower's output end is connected to the variable frequency water ring vacuum pump via a pipeline. The cooling tower has a variable frequency fan. A temperature sensor is installed on the pipeline between the cooling tower and the variable frequency water ring vacuum pump. The temperature sensor, water pump, and variable frequency fan are connected to the electrical control device via wiring.

[0020] This utility model has the following advantages:

[0021] Using this invention, when the methane concentration detected by the methane concentration sensor is lower than P1, there is no need for manual on-site inspection. Ineffective boreholes can be closed in time, avoiding wasted energy from ineffective extraction, and the extraction negative pressure is concentrated on effective boreholes, thereby improving extraction efficiency.

[0022] Staff in the monitoring room can centrally monitor the status of the entire system and each extraction branch pipe through the display screen.

[0023] When the overall pressure value detected by the main pressure sensor rises, the operator can increase the operating frequency of the variable frequency water ring vacuum pump through the electronic control device. Conversely, when the overall pressure value detected by the main pressure sensor falls, the operator can decrease the operating frequency of the variable frequency water ring vacuum pump through the electronic control device. This ensures that the working state of the variable frequency water ring vacuum pump matches the actual load requirements, avoiding both the energy waste of a constant speed pump underpowered at low loads and the inefficient extraction of a constant speed pump underpowered at high loads.

[0024] When the pressure sensors on different branch pipes detect significant differences, operators can adjust the electric regulating valves. Specifically, for extraction branch pipes with relatively lower pressure, the opening degree of the corresponding electric regulating valve is reduced; for extraction branch pipes with relatively higher pressure, the opening degree of the corresponding electric regulating valve is increased. This maintains uniform extraction from each gas extraction hole. Uniform extraction reduces air contamination, increases the concentration of extracted gas, and reduces equipment wear caused by localized high loads, extending the lifespan of vacuum pumps, pipelines, and other facilities. The above control process can be centrally completed in the monitoring room where the electrical control device is located, eliminating the need for on-site inspections.

[0025] Gas-liquid separators can prevent excessive moisture in the methane gas supplied downstream, ensuring gas quality and preventing liquid water from entering the gas storage tank or subsequent pipelines, thus avoiding corrosion and blockage of related equipment.

[0026] When staff in the monitoring room find that the water level in the gas-liquid separator is high, they can promptly open the drain solenoid valve through the electronic control device to drain the water, and then close the drain solenoid valve after draining. The entire process does not require on-site inspection or manual valve operation, which can prevent the water level from being too high and affecting the normal operation of the system.

[0027] The water circulation system ensures the sealing efficiency of the variable frequency water ring vacuum pump and improves system stability. When the temperature sensor detects a high temperature, the operator increases the operating frequency of the variable frequency fan to improve the cooling tower's heat dissipation efficiency, thereby lowering the water temperature. Conversely, when the temperature sensor detects a low temperature, the operator decreases the operating frequency of the variable frequency fan to reduce the cooling tower's heat dissipation efficiency, thus lowering energy consumption. The water circulation system provides the equipment foundation for operators to stabilize water temperature and balance heat dissipation and energy consumption. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of this utility model. Figure 1 The thick black solid line represents the water pipeline, the thick red solid line represents the gas pipeline, and the electrical control circuit is represented by the thin black solid line. To simplify the diagram and avoid clutter, only the methane concentration sensor, electric regulating valve, and branch pressure sensor are shown on one extraction branch pipe. Detailed Implementation

[0029] like Figure 1 As shown, the variable frequency gas extraction and control system of this utility model includes an extraction main pipe 6, which extends longitudinally and is connected to multiple extraction branch pipes 2; each extraction branch pipe 2 is connected to a gas extraction hole in a one-to-one manner for transporting gas; each extraction branch pipe 2 is connected to a methane concentration sensor 1 and an electric regulating valve 4, which is used to control the gas flow rate.

[0030] The extraction main pipe 6 is equipped with a main pipe pressure sensor 5 for monitoring the main pipe pressure; the extraction main pipe 6 is connected to the inlet of the variable frequency water ring vacuum pump, which is used to generate negative pressure to extract gas; the exhaust port of the variable frequency water ring vacuum pump is connected to the storage container or gas-using unit through the gas supply pipeline 13; the storage container or gas-using unit is of conventional technology and is not shown in the figure.

[0031] The methane concentration sensor 1, the electric regulating valve 4, and the main pipe pressure sensor 5 are all connected to the same electronic control device 21 via wiring. The electronic control device 21 has a concentration threshold P1 pre-stored (e.g., 0.5%, which can be displayed on the screen). The electronic control device 21 is an integrated circuit or a microcontroller, preferably a microcontroller.

[0032] When the methane concentration detected by methane concentration sensor 1 is lower than P1, the corresponding electric regulating valve 4 is closed.

[0033] In this invention, the concentration threshold is pre-stored as a fixed parameter in the microcontroller. The comparison logic is implemented by the microcontroller hardware or basic firmware, and the level signal directly drives the electric regulating valve 4 to close. Alternatively, the comparison logic can be implemented without a microcontroller, and the staff in the monitoring room can monitor the methane concentration status through the electronic control device 21 and the display screen. When the staff detects that the methane concentration detected by a certain methane concentration sensor 1 is lower than P1, they manually close the corresponding electric regulating valve 4 through the electronic control device 21. The variable frequency water ring vacuum pump includes a water ring vacuum pump 7, a frequency converter 8, and a variable frequency motor 9. The frequency converter 8 controls the variable frequency motor 9, and the variable frequency motor 9 drives the water ring vacuum pump 7. This is conventional technology and will not be described in detail. The specific value of P1 is specified by the staff based on the extraction target and the specific on-site conditions.

[0034] When the methane concentration detected by the methane concentration sensor 1 is lower than P1, there is no need for manual on-site inspection and actual valve operation. Ineffective boreholes can be closed in time, avoiding wasted energy from ineffective extraction, and the extraction negative pressure is concentrated on the effective boreholes, thereby improving extraction efficiency.

[0035] The electronic control device 21 is connected to the computer 20, which has a display screen; the electronic control device 21, the computer 20, and the display screen are located in the monitoring room;

[0036] Each extraction branch pipe 2 is connected to a branch pipe pressure sensor 3, which is connected to the electrical control device 21 via a circuit.

[0037] The exhaust port of the variable frequency water ring vacuum pump is connected to a gas-water separator 11. The top of the gas-water separator 11 is connected to the gas supply pipeline 13 and is connected to the storage container or gas-using unit through the gas supply pipeline 13.

[0038] A pressure-type liquid level sensor 14 is installed at the bottom of the gas-liquid separator 11, and a drain solenoid valve 15 is connected downward to the gas-liquid separator 11. The drain solenoid valve 15 and the pressure-type liquid level sensor 14 are respectively connected to the electronic control device 21 through lines.

[0039] The gas-water separator 11 can prevent excessive moisture in the methane gas supplied downstream, ensuring the quality of the gas supply and preventing liquid water from entering the gas storage tank or subsequent pipelines, which could cause corrosion, blockage, or other problems to related equipment.

[0040] When staff in the monitoring room find that the water level in the gas-water separator 11 is high, they can open the drain solenoid valve 15 in time through the electronic control device 21 to drain the water, and then close the drain solenoid valve 15 after draining the water. The whole process does not require on-site inspection or manual operation of the valve, which can prevent the water level from being too high and affecting the normal operation of the system. The variable frequency water ring vacuum pump is connected to a water circulation system, which is used to ensure the sealing of the variable frequency water ring vacuum pump. The water circulation system includes an upper water tank 17, a lower water tank 16, and a cooling tower 12. A drain solenoid valve 15 is connected to a drain pipe 23, which leads to the lower water tank 16. A water pump 18 is connected to the lower water tank 16, and the outlet pipe of the water pump 18 is connected to the upper water tank, which is higher than the cooling tower 12 (the upper water tank is not shown above the cooling tower 12 in the figure for the sake of neatness) and is connected to the input end of the cooling tower 12 through a pipeline. The cooling tower 12 is higher than the variable frequency water ring vacuum pump, and the output end of the cooling tower 12 is connected to the variable frequency water ring vacuum pump through a pipeline. The cooling tower 12 has a variable frequency fan 24. A temperature sensor 10 is installed on the pipeline between the cooling tower 12 and the variable frequency water ring vacuum pump. The temperature sensor 10, the water pump 18, and the variable frequency fan 24 are respectively connected to the electrical control device 21 through lines.

[0041] The water circulation system ensures the sealing efficiency of the variable frequency water ring vacuum pump and improves system stability. The water circulation system also provides the equipment foundation for operators to stabilize water temperature and balance heat dissipation and energy consumption.

[0042] The working process of this utility model is described below.

[0043] I. Gas Drainage and Flow Control

[0044] During the extraction phase, the gas intake and branch pipes are regulated. Methane gas enters the corresponding extraction branch pipe 2 from each extraction hole, and the methane concentration sensor 1 on the branch pipe monitors the methane concentration in real time.

[0045] When the methane concentration detected by a methane concentration sensor 1 in a branch pipe is lower than a preset threshold (P1, e.g., 0.5%), the staff in the monitoring room close the electric regulating valve 4 of that branch pipe via the electronic control device 21, stopping ineffective extraction. This avoids energy waste from low-concentration gas extraction, concentrates negative pressure resources on effective boreholes, and improves extraction efficiency. This process eliminates the need for manual on-site inspection, reduces response delays, and lowers labor intensity.

[0046] During the extraction phase, the pressure of the main pipe is regulated. The main pipe pressure sensor 5 monitors the pressure of the extraction main pipe 6 in real time. When the pressure is too high, the operator increases the speed of the variable frequency water ring vacuum pump via the electronic control device 21 to increase the extraction volume; when the pressure is too low, the operator decreases the speed to reduce energy consumption. There is no absolute standard for "too high" or "too low" here; it is determined by the operator. Variable frequency technology avoids the problems of a constant speed pump being underpowered or underpowered, significantly reducing energy consumption and matching the operating conditions of the variable frequency water ring vacuum pump with the system pressure state, maintaining stable system pressure and ensuring continuous extraction.

[0047] II. Gas-liquid separation and drainage

[0048] The gas discharged from the variable frequency water ring vacuum pump enters the gas-water separator 11, where liquid water is separated, and then sent to the downstream storage container (gas tank) or the gas-using unit.

[0049] The pressure-type liquid level sensor 14 continuously monitors the water level at the bottom of the separator. When the staff in the monitoring room find that the water level in the gas-water separator 11 is high, they can open the drain solenoid valve 15 through the electronic control device 21 to drain the water. After draining the water, the drain solenoid valve 15 is closed, eliminating the need for on-site inspection.

[0050] III. Temperature control of water circulation system

[0051] Cooling tower 12 adjusts its heat dissipation efficiency via variable frequency fan 24. Temperature sensor 10 monitors the cooling water temperature in real time. When the temperature sensor 10 detects a high temperature, the operator increases the operating frequency of variable frequency fan 24 to improve the cooling tower 12's heat dissipation efficiency, thereby lowering the water temperature. Conversely, when the temperature sensor 10 detects a low temperature, the operator decreases the operating frequency of variable frequency fan 24 to reduce the cooling tower 12's heat dissipation efficiency, thus reducing energy consumption. This allows for on-demand adjustment of heat dissipation intensity, avoiding the ineffective energy consumption of constant-speed fans. It also maintains the water temperature within the optimal range for the specific water ring vacuum pump, ensuring the vacuum pump's sealing performance.

[0052] IV. Centralized Monitoring and Balanced Sampling

[0053] The electrical control device 21 is connected to the computer 20 and the display screen, which centrally displays parameters such as the pressure of each branch pipe, methane concentration, and main pipe pressure. Staff in the monitoring room can centrally monitor the overall system and the status of each extraction branch pipe 2 via the display screen.

[0054] When the overall pressure value monitored by the main pressure sensor 5 increases, the operator can increase the operating frequency of the variable frequency water ring vacuum pump through the electronic control device 21. Conversely, when the overall pressure value monitored by the main pressure sensor 5 decreases, the operator can decrease the operating frequency of the variable frequency water ring vacuum pump through the electronic control device 21. This allows the operating state of the variable frequency water ring vacuum pump to match the actual load requirements, thus avoiding both the energy waste of a constant speed pump under low load and the inefficient extraction of a constant speed pump under high load.

[0055] When the pressure detected by the pressure sensors 3 in each branch pipe differs too much, the operator can adjust the electric regulating valves 4.

[0056] Specifically, for the extraction branch pipe 2 with relatively low pressure, the operator reduces the opening degree of its corresponding electric regulating valve 4; for the extraction branch pipe 2 with relatively high pressure, the operator increases the opening degree of its corresponding electric regulating valve 4. This maintains uniform extraction from each gas extraction hole. Uniform extraction reduces air mixing, increases the concentration of extracted gas, and reduces equipment wear caused by localized high loads, extending the lifespan of vacuum pumps, pipelines, and other facilities. The above control process can be centrally completed in the monitoring room where the electrical control device 21 is located, without the need for on-site inspection.

[0057] The above embodiments are only used to illustrate and not limit the technical solutions of this utility model. Although the utility model has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the utility model without departing from the spirit and scope of the utility model. Any modifications or partial substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A variable frequency gas extraction control system, comprising an extraction main pipe, the extraction main pipe extending longitudinally and being connected to a plurality of extraction branch pipes; each extraction branch pipe is connected to a gas extraction hole one by one, and is used for conveying gas; characterized in that: Each extraction branch pipe is connected to a methane concentration sensor and an electric regulating valve, which is used to control the gas flow rate. A main pipe pressure sensor is installed on the extraction main pipe; the extraction main pipe is connected to the inlet of the variable frequency water ring vacuum pump, which is used to generate negative pressure to extract gas; the exhaust port of the variable frequency water ring vacuum pump is connected to the storage container or gas-using unit through the gas delivery pipeline. The methane concentration sensor, electric regulating valve, and main pipe pressure sensor are all connected to the same electronic control device via a circuit. The electronic control device is a microcontroller or integrated circuit. The main pipe pressure sensor transmits the pressure signal to the microcontroller or integrated circuit via a circuit. The microcontroller or integrated circuit adjusts the operating frequency of the variable frequency water ring vacuum pump according to the pressure signal. The electronic control device has a pre-stored concentration threshold P1; When the methane concentration detected by the methane concentration sensor is lower than P1, the corresponding electric regulating valve is closed. The exhaust port of the variable frequency water ring vacuum pump is connected to a gas-liquid separator. The top of the gas-liquid separator is connected to the gas delivery pipeline and then connected to a storage container or a gas-using unit through the gas delivery pipeline. A pressure-type liquid level sensor is installed at the bottom of the gas-liquid separator, and a drain solenoid valve is connected downwards to the gas-liquid separator; the drain solenoid valve and the pressure-type liquid level sensor are respectively connected to the electronic control device through wiring. The variable frequency water ring vacuum pump is connected to a water circulation system, which is used to ensure the sealing condition of the variable frequency water ring vacuum pump. The water circulation system includes an upper water tank, a lower water tank, and a cooling tower; a drain solenoid valve is connected to a drain pipe, which leads to the lower water tank; a water pump is connected to the lower water tank, and the water pump's outlet pipe is connected to the upper water tank, which is higher than the cooling tower and connected to the input end of the cooling tower via a pipeline; the output end of the cooling tower is connected to a variable frequency water ring vacuum pump via a pipeline; the cooling tower has a variable frequency fan; a temperature sensor is installed on the pipeline between the cooling tower and the variable frequency water ring vacuum pump, and the temperature sensor, water pump, and variable frequency fan are respectively connected to the electrical control device via wiring.

2. The variable frequency gas extraction regulation system according to claim 1, characterized in that: The electrical control device is connected to a computer, which has a display screen; the electrical control device, computer, and display screen are located in the monitoring room. Each extraction branch pipe is connected to a branch pipe pressure sensor, which is connected to the electrical control device via wiring.

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