Dual-loop control system for stable operation of gas extraction pumps

Abstract

A dual-loop control system for the stable operation of a gas extraction pump is provided, comprising a programmable control cabinet, a host computer, a gas-water circulation pump, a pump motor, and a water-gas separator. The pump motor output is connected to the gas-water circulation pump power input via a pump reducer. The gas-water circulation pump water-gas outlet is connected to the water-gas inlet of the water-gas separator. The water outlet of the water-gas separator is connected to the cooling water pool inlet. The cooling water pool outlet is connected to the high-level water pool inlet. The high-level water pool outlet is connected to the gas-water circulation pump inlet via an inlet pipe. The connecting pipe between the gas-water circulation pump and the high-level water pool is equipped with a PLC constant pressure control box and a position-type electric regulating valve. A pipeline flow meter is provided on the underground gas extraction and prevention pipeline. This system truly monitors the various working states and operating parameters of the gas extraction pump and can remotely control operations, enabling unmanned operation in hazardous underground environments, thereby saving energy, reducing labor intensity, lowering operating costs, and extending equipment life.

Description

Technical Field

[0001] The patent of this invention belongs to the field of gas extraction technology, and specifically relates to a complex regulation and control system for the stable operation of a gas extraction pump. Background Art

[0002] The main function of a gas drainage pumping station is to aggregate the capillary drainage pipes of the existing coal seam and the empty coal seams underground, and then lead them to the surface drainage pumping station through the main pipeline. When the drainage pump is running, the pipeline creates a negative pressure, which draws the underground gas through the pipeline to the surface for discharge or to a gas power plant for gas utilization. When the gas drainage pumping station is in operation, it first opens the exhaust valve and starts the pump motor. The operation of the pump motor drives the reducer to rotate, thereby driving the water circulation pump to work. The air inlet valve is then opened; the water inlet valve of the water circulation pump is opened, and the water circulation pump rotates, dispersing the water entering the cavity until the shell and the rotating body form a seal, creating a vacuum, which pushes the gas into the steam-water separator and discharges the gas.

[0003] The water intake of the water circulation pump has two functions:

[0004] First, it determines the vacuum degree of the circulating pump. When the water volume is small, the vacuum degree is small and cannot meet the requirements, which affects the pumping efficiency. When the water volume is large, the vacuum degree can meet the requirements, but the motor load current increases.

[0005] Secondly, the pump body is water-cooled. A large amount of water removes more heat, keeping the pump body temperature low; a small amount of water removes less heat, causing the equipment to overheat and affect its stable operation. At the same time, because underground working conditions are changeable and irregular, changes in working conditions can seriously affect the gas concentration and the gas flow entering the gas extraction pump. Therefore, it is necessary to adjust the water intake of the extraction pump in real time according to the actual working conditions on site to achieve an appropriate amount of water intake, so that the water circulation pump can maintain the negative pressure within a normal range and operate stably.

[0006] That is, the water inlet flow and the vacuum degree of the vacuum pump reach a balance value. The two main specific parameters that characterize the vacuum degree of the vacuum pump are negative pressure and load current. Currently, manual on-site operation and manual adjustment are used to adjust the valve opening.

[0007] Based on the comprehensive consideration of measured negative pressure, flow, temperature, gas concentration and other parameters, the water inlet of the water ring pump is adjusted by local, manual and artificial operation. It is impossible to grasp the operating status of the equipment in real time, and it is impossible to monitor and control the field data in real time. The level of modern mine management is low. Therefore, it is necessary to propose improvements. Summary of the Invention

[0008] The technical problem solved by the present invention is: to provide a dual-loop control system for the stable operation of a gas extraction pump, a gas extraction pump control system based on a programmable control cabinet and adopting a dual-loop control system. The control system of the present invention can truly monitor various working states and operating parameters of the gas extraction pump, and can remotely and conveniently control and operate the monitoring on-site equipment, thereby realizing unmanned supervision of dangerous underground environments, ensuring the safety of system on-duty personnel, improving the level of modern mine management, and achieving the purpose of effectively saving energy, reducing labor intensity, reducing operating costs and extending equipment service life.

[0009] The technical solution adopted by the present invention is as follows: a gas extraction pump control system, comprising a programmable control cabinet, a host computer, a gas-water circulation pump, a pump motor and a water-gas separator, wherein the output end of the pump motor is connected to the power input end of the gas-water circulation pump through a pump reducer, the water-gas outlet of the gas-water circulation pump is connected to the water-gas inlet of the water-gas separator, the water outlet of the water-gas separator is connected to the water inlet of the cooling water pool, the water outlet of the cooling water pool is connected to the water inlet of the high-level water pool, the water outlet of the high-level water pool is connected to the water inlet of the gas-water circulation pump through a water inlet pipe, and the connecting pipe between the gas-water circulation pump and the high-level water pool is connected. A PLC constant pressure control box and a position electric regulating valve are provided on the road. A boosting valve is provided in the PLC constant pressure control box. The boosting valve inlet is connected to the water inlet of the high-level water tank, and the boosting valve outlet is connected to the inlet of the position electric regulating valve. The outlet of the position electric regulating valve is connected to the water inlet of the gas-water circulating pump. A pipeline flow meter is provided on the underground gas extraction pipeline connected to the air inlet of the gas-water circulating pump. The gas-water circulating pump, the position electric regulating valve, the pipeline flow meter, the pump motor and the water-gas separator are all electrically connected to the programmable control cabinet, and the programmable control cabinet is electrically connected to the host computer.

[0010] Further limitation of the above technical solution: a PID controller is provided in the PLC constant pressure control box, and the PID controller ensures the constant pressure of the circulating water pipeline, and provides a guarantee for accurately controlling the water inlet accuracy of the water circulating pump when the position of the water inlet regulating valve is adjusted; the programmable control cabinet is provided with a PID controller, and the PID controller adopts a dual-loop control system, which takes the negative pressure of the gas-water circulating pump and the load of the pump motor as dual set quantities, thereby adjusting the opening of the water inlet valve of the gas-water circulating pump and detecting the feedback of the negative pressure and load.

[0011] To further limit the above technical solution, a pressure gauge is connected between the boost valve and the position electric regulating valve, and the PLC constant pressure control box is also provided with a pressure transmitter and a frequency converter electrically connected to the boost valve.

[0012] To further limit the above technical solution, a pump air inlet valve is provided on the air inlet of the gas-water circulation pump connected to the underground gas extraction and prevention pipeline, and a pump exhaust valve is provided on the exhaust port of the water-gas separator connected to the gas exhaust pipeline.

[0013] The advantages of the control algorithm proposed in this paper compared with the existing technology are:

[0014] This system is improved on the basis of the original gas drainage pump control. It adopts a dual-loop control system. It can truly monitor the various working conditions and operating parameters of the gas drainage pump, and can remotely and conveniently control the monitoring on-site equipment, realizing unmanned supervision in dangerous underground environments, ensuring the safety of system on-duty personnel, improving the level of modern mine management, and achieving the goals of effectively saving energy, reducing labor intensity, reducing operating costs and extending equipment life. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the structure of the gas drainage pump station in the present invention;

[0016] Figure 2 Schematic diagram of the control of the dual-loop control system of the present invention;

[0017] Figure 3 This is a schematic diagram of the overall control of the gas extraction pump station in the present invention. DETAILED DESCRIPTION

[0018] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts are within the scope of protection of the present invention.

[0019] In the present invention, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, the phrase "comprising an element" does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0020] See also Figure 1-3 , details the embodiments of the present invention.

[0021] Dual-loop control system for stable operation of gas extraction pumps, such as Figure 1 and 3As shown, it includes a programmable control cabinet 1, a host computer 2, a gas-water circulating pump 3, a pump motor 4 and a water-gas separator 6. The output end of the pump motor 4 is connected to the power input end of the gas-water circulating pump 3 through a pump reducer 5. The water-gas outlet of the gas-water circulating pump 3 is connected to the water-gas inlet of the water-gas separator 6. A pump air inlet valve 7 is provided on the air inlet of the gas-water circulating pump 3 connected to the underground gas extraction and prevention pipeline. A pump exhaust valve 8 is provided on the exhaust port of the water-gas separator 6 connected to the gas exhaust pipeline. The water outlet of the water-gas separator 6 is connected to the water inlet of the cooling water pool 14, the water outlet of the cooling water pool 14 is connected to the water inlet of the high-level water pool 13, the water outlet of the high-level water pool 13 is connected to the water inlet of the gas-water circulating pump 3 through an inlet pipe, and a PLC constant pressure control box 11 and a position electric regulating valve 9 are provided on the connecting pipe between the gas-water circulating pump 3 and the high-level water pool 13. A boosting valve 12 is provided in the PLC constant pressure control box 11, and a pressure transmitter and a frequency converter electrically connected to the boosting valve 12 are also provided in the PLC constant pressure control box 11. The inlet of the boosting valve 12 is connected to the water outlet of the high-level water pool 13, and the outlet of the boosting valve 12 is connected to the inlet of the position electric regulating valve 9. A pressure gauge 10 is connected between the boosting valve 12 and the position electric regulating valve 9, and the outlet of the position electric regulating valve 9 is connected to the water inlet of the gas-water circulating pump 3.

[0022] Preferably, the position type electric regulating valve 9 is controlled by a CPU module in a programmable control cabinet 1, wherein a PID controller is provided. Figure 2 As shown, the programmable control cabinet 1 employs a dual-loop control system, using the negative pressure of the gas-water circulating pump 3 and the load of the pump motor 4 as dual setpoints to adjust the opening of the gas-water circulating pump 3's water inlet valve and the feedback from the negative pressure and load detection to achieve stability. A pipeline flowmeter 15 is installed on the underground gas extraction and prevention pipeline connected to the gas-water circulating pump 3's air inlet. The gas-water circulating pump 3, position-type electric regulating valve 9, pipeline flowmeter 15, pump motor 4, and water-gas separator 6 are all electrically connected to the programmable control cabinet 1, which is in turn electrically connected to the host computer 2.

[0023] Working principle:

[0024] During operation, the pump exhaust valve 8 is first opened, and the pump motor 4 is started. The operation of the pump motor 4 drives the pump reducer 5 to rotate, thereby driving the gas-water circulation pump 3 to work, and then the pump inlet valve 7 is opened. The water inlet valve of the gas-water circulation pump 3 is opened, and the gas-water circulation pump 3 rotates, rotating and dispersing the water entering the cavity until the shell and the rotating body form a seal, forming a vacuum, thereby pushing the gas into the water-gas separator 6 and exhausting the gas. The opening of the water circulation valve of the gas-water circulation pump 3, that is, the water flow entering the gas-water circulation pump 3, determines the stable operation of the pump. When the valve opening is too small, the water flow is small, the pump vacuum is low, and the air extraction efficiency is low. When the valve opening is too large, the water flow is large, and the pump vacuum is high, the load on the pump motor 4 increases, and the load on the water-gas separator 6 increases. The water inlet volume and the negative pressure reach a balanced relationship, which is a typical large hysteresis inertia link. The control system of the present invention changes the water inlet valve of the gas-water circulating pump 3 into a position-type electric regulating valve 9 with a feedback value. The controller unit in the programmable control cabinet is used to take the load and the negative pressure as dual given quantities, adjust the valve opening, and detect the feedback of the negative pressure and the load, so as to achieve a balance.

[0025] 1. Gas pump stable control method:

[0026] First, the water supply should be adjusted. Since the pipeline pressure is not constant, the liquid level of the high-level water tank is changing, which affects the control accuracy. Therefore, in the improvement of the system, a PLC constant pressure control box 11 and its internal booster valve 12, pressure transmitter and frequency converter are added to achieve constant pressure water supply in the water inlet pipeline.

[0027] The negative pressure standard of the gas-water circulating pump 3 is a variable range (30kPa_40kPa). It is not that the smaller the negative pressure, the greater the water flow; the larger the negative pressure, the smaller the water flow, forming a suitable vacuum degree;

[0028] This system program is written to run on the controller unit in the programmable control cabinet 1. The control cabinet can collect the negative pressure of the water ring pump 3 and the gas-water circulation pump 3 during operation, as well as the load current of the pump motor 4 that drives the gas-water circulation pump 3 to rotate, obtain the above parameters, and establish a mathematical model to control the size of the water inlet regulating valve when the gas-water circulation pump 3 is running, thereby controlling the negative pressure of the gas-water circulation pump 3 to be maintained within a stable range.

[0029] Second, the control strategy of this system focuses on the two main parameters that characterize the vacuum degree of the gas-water circulating pump 3: negative pressure and load current; these are used as the main control indicators.

[0030] The specific strategies are as follows:

[0031] 1) Under normal circumstances, the water inlet is adjusted so that the negative pressure of the gas-water circulation pump 3 is controlled between 30-45Kpa, and the load current is within 0.8 times the rated current. The system does not make any adjustments.

[0032] 2) The negative pressure of the gas-water circulating pump 3 is controlled between 30-45KPa. Even if the negative pressure is normal, if the load current is greater than 0.8 times the rated current, the outer loop current control should be given priority to reduce the water intake so that the load current is reduced to the normal range.

[0033] 3) If the negative pressure increases beyond 45kPa to 50kPa, as long as the load current is within the normal range and the water inlet is not adjusted, it is regarded as a disturbance signal and the system is allowed to automatically adjust to the stable range.

[0034] 4) If the negative pressure increases by more than 50 kPa, adjust the water inlet so that the negative pressure of the gas-water circulating pump 3 returns to between 30 and 45 kPa. At the same time, refer to the characteristic value of the load current. If the current is greater than 0.8 times the rated current, the water inlet should be reduced immediately to first reduce the load current to the normal range. Then, delay, collect various parameters, and adjust the water inlet so that the negative pressure characteristic value enters the stable range.

[0035] This system is improved on the basis of the original gas drainage pump control. It can truly monitor the various working conditions and operating parameters of the gas drainage pump, and can conveniently control the monitoring equipment remotely as needed, realizing unmanned supervision in dangerous underground environments, ensuring the safety of system on-duty personnel, improving the level of modern mine management, and achieving the goals of effectively saving energy, reducing labor intensity, reducing operating costs and extending equipment service life.

[0036] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0037] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A dual-loop control system for stable operation of a gas extraction pump, comprising a programmable control cabinet (1), a host computer (2), a gas-water circulation pump (3), a pump motor (4) and a water-gas separator (6), wherein the output end of the pump motor (4) is connected to the power input end of the gas-water circulation pump (3) through a pump reducer (5), the water-gas outlet of the gas-water circulation pump (3) is connected to the water-gas inlet of the water-gas separator (6), the water outlet of the water-gas separator (6) is connected to the water inlet of a cooling water pool (14), the water outlet of the cooling water pool (14) is connected to the water inlet of a high-level water pool (13), and the water outlet of the high-level water pool (13) is connected to the water inlet of the gas-water circulation pump (3) through a water inlet pipeline, characterized in that: A PLC constant pressure control box (11) and a position-type electric regulating valve (9) are provided on the connecting pipeline between the gas-water circulation pump (3) and the high-level water tank (13). A booster valve (12) is provided in the PLC constant pressure control box (11). The inlet of the booster valve (12) is connected to the water outlet of the high-level water tank (13). The outlet of the booster valve (12) is connected to the inlet of the position-type electric regulating valve (9). The outlet of the position-type electric regulating valve (9) is connected to the water inlet of the gas-water circulation pump (3). A pipeline flowmeter (15) is provided on the underground gas extraction pipeline connected to the air inlet of the gas-water circulation pump (3). The gas-water circulation pump (3), the position-type electric regulating valve (9), the pipeline flowmeter (15), the pump motor (4) and the water-gas separator (6) are all electrically connected to the programmable control cabinet (1). The programmable control cabinet (1) is electrically connected to the host computer (2). The position-type electric regulating valve (9) is connected to the water inlet of the gas-water circulation pump (3). The programmable control cabinet (1) is controlled, and a CPU module in the programmable control cabinet (1) is provided with a double-loop control system. The double-loop control system uses the negative pressure of the gas-water circulation pump (3) and the load current of the pump motor (4) as dual set quantities to adjust the opening of the water inlet valve of the gas-water circulation pump (3), and simultaneously detects the negative pressure and load current parameters. The control strategy of the double-loop control system includes: if the negative pressure is maintained at 30-45KPa and the load current is ≤ 0.8 times of the rated current, the system does not adjust; if the load current is greater than 0.8 times of the rated current, the water inlet is preferentially reduced to reduce the motor load; if the negative pressure increases to 45-50KPa but the current is normal, it is regarded as a "disturbance signal" and the system is waiting for automatic adjustment; if the negative pressure is greater than 50KPa, the water inlet is adjusted to make the negative pressure fall back to 30-45KPa; if the current is greater than 0.8 times of the rated current during the adjustment process, the water inlet is immediately preferentially reduced and the negative pressure is readjusted.

2. The dual-loop control system for stable operation of a gas extraction pump according to claim 1, characterized in that: An intelligent pressure gauge (10) is connected between the boost valve (12) and the position electric regulating valve (9), and a pressure transmitter and a frequency converter electrically connected to the boost valve (12) are also provided in the PLC constant pressure control box (11).

3. The dual-loop control system for stable operation of a gas extraction pump according to claim 1, characterized in that: The gas-water circulation pump (3) is provided with a pump air inlet valve (7), a pressure sensor, and a gas concentration detection unit at its air inlet connected to the underground gas extraction and prevention pipeline, and the water-gas separator (6) is provided with a pump air exhaust valve (8), a temperature sensor, and a liquid level meter at its air outlet connected to the gas exhaust pipeline.

Images