Device for detecting content of methane gas in crude oil

Abstract

The utility model discloses a device for detecting the content of methane gas in crude oil, which comprises a mounting frame, a controller and a speed reduction linear motor, a hydraulic cylinder and a heat preservation oil tank are arranged on the mounting frame, a pressure transmitter is arranged in the hydraulic cylinder, and the heat preservation oil tank is of an annular box body structure and is arranged around the outer side of the hydraulic cylinder; piston holes are formed in the lower ends of the hydraulic cylinders; piston rods are arranged in the piston holes through deceleration linear motors; a grating ruler for measuring the moving distance of the piston rod is arranged on the mounting frame; and the controller is electrically connected with the pressure transmitter, the deceleration linear motor and the grating ruler. According to the utility model, a crude oil sample is pressurized in the hydraulic cylinder, so that gas in crude oil can be dissolved in oil liquid, volume difference is generated, and the content of the gas in the crude oil can be accurately judged; gas-liquid separation of the crude oil is not needed, so that inaccurate measurement results caused by incomplete gas-liquid separation when the content of methane gas in the crude oil is detected are avoided.

Description

Technical Field

[0001] This utility model relates to the field of crude oil detection technology, specifically to a device for detecting the methane content in crude oil. Background Technology

[0002] Crude oil often contains gaseous impurities such as water vapor, hydrogen sulfide, carbon dioxide, and methane during extraction and transportation. The mixing state of these gases with crude oil changes with temperature and pressure. For example, methane is a flammable and explosive gas; excessive levels can pose safety hazards and affect crude oil quality and subsequent processing efficiency. Therefore, a precise crude oil methane content detection device is needed to ensure the safety and stability of the crude oil extraction and transportation process.

[0003] In the prior art, utility model patent CN202020943352.1 discloses an oil and gas metering device, including a separation device, a pipeline, a valve, a gas flow meter, and a crude oil flow meter. The outlet end of the separation device is connected to the valve through a pipeline. The valve is a gas phase pipeline valve controlled by the liquid level. The gas phase outlet end of the valve is connected to the inlet end of the gas flow meter through a pipeline. The liquid phase outlet end of the valve is connected to the inlet end of the crude oil flow meter through a pipeline. This oil and gas metering device achieves gas-liquid separation. The gas flow meter is used to detect the gas flow rate, and the crude oil flow meter is used to detect the amount of liquid crude oil. The gas in the liquid crude oil is separated, reducing its influence on the liquid phase metering and significantly improving the metering accuracy.

[0004] The aforementioned patent provides a device that can first separate the gas and liquid phases of crude oil and then detect the gas. This device can also be used to assist in the detection of methane gas content in crude oil. However, when using this device to assist in the detection of methane gas in crude oil, it is necessary to first separate the oil and gas phases. Incomplete oil and gas separation will lead to errors in the detection data of methane gas content in crude oil, resulting in inaccurate detection results. Utility Model Content

[0005] The purpose of this invention is to provide a device for detecting the methane content in crude oil, aiming to improve the problem that the existing technology requires the separation of oil and gas phases before detecting methane in crude oil, which can easily lead to inaccurate detection results due to incomplete oil and gas separation.

[0006] This invention is implemented as follows: A device for detecting methane content in crude oil includes a mounting frame and a controller, as well as a geared linear motor; the mounting frame is equipped with a hydraulic cylinder and an insulated oil tank, the hydraulic cylinder contains a pressure transmitter, and the insulated oil tank has an annular structure and surrounds the outside of the hydraulic cylinder; the lower end of the hydraulic cylinder has a piston hole, and a piston rod is mounted in the piston hole via the geared linear motor; the mounting frame is equipped with a grating ruler for measuring the movement distance of the piston rod; the controller is electrically connected to the pressure transmitter, the geared linear motor, and the grating ruler.

[0007] Preferably, the mounting frame is provided with a seating plate, support legs and a base from top to bottom, and the seating plate is mounted on the base via the support legs; the hydraulic cylinder and the insulated oil tank are mounted on the seating plate; and multiple casters are arranged in sequence along the circumference of the bottom of the base.

[0008] Preferably, the landing plate further includes a through groove, and the piston hole extends through the through groove to the lower end of the landing plate.

[0009] Preferably, a first support frame is provided on the base, the decelerated linear motor is mounted on the first support frame, the decelerated linear motor is provided with a linear motion output shaft, a piston rod is provided at the upper end of the output shaft, and the piston rod is slidably disposed in a piston hole.

[0010] Preferably, the base is further provided with a second support frame, the grating ruler is mounted on the second support frame and its measuring direction is parallel to the output shaft, and the measuring component of the grating ruler is connected to the shaft body of the output shaft.

[0011] Preferably, the upper end of the hydraulic cylinder is provided with an exhaust port, and the lower end is provided with an oil inlet and outlet located in the through groove; both the exhaust port and the oil inlet and outlet are provided with ball valve switches for opening and closing.

[0012] Preferably, the upper end of the insulated oil tank is provided with an oil filling port, and the inside of the insulated oil tank is provided with a heater and a temperature transmitter; the oil filling port is provided with a ball valve switch for opening and closing, and the heater and the temperature transmitter are both electrically connected to the controller.

[0013] Compared with the prior art, the beneficial effects of this utility model are:

[0014] 1. This utility model pressurizes the crude oil sample in a hydraulic cylinder, thereby dissolving the gas in the crude oil into the oil and creating a volume difference. This allows for accurate determination of the gas content in the crude oil without the need for gas-liquid separation, thus avoiding the problem of inaccurate measurement results caused by incomplete gas-liquid separation when detecting methane gas content in crude oil.

[0015] 2. This utility model, by setting universal wheels at the bottom of the base, allows for easy movement of the equipment and facilitates the adjustment of the equipment position by the measuring personnel at any time. Attached Figure Description

[0016] Figure 1 This is a three-dimensional structural schematic diagram of the present invention;

[0017] Figure 2 This is a cross-sectional structural schematic diagram of the present invention;

[0018] Figure 3 This is a cross-sectional structural diagram of the mounting bracket, the deceleration linear motor, and the grating ruler of this utility model;

[0019] Figure 4 This is a three-dimensional structural diagram of the mounting bracket, the deceleration linear motor, and the grating ruler of this utility model;

[0020] Figure 5 This is a schematic diagram of the structure of the hydraulic cylinder of this utility model;

[0021] Figure 6 This is a schematic diagram of the structure of the insulated oil tank of this utility model.

[0022] In the diagram: 1. Mounting frame; 101. Sealing plate; 102. Support leg; 103. Base; 104. First support frame; 105. Second support frame; 106. Through slot; 107. Caster wheel; 2. Hydraulic cylinder; 201. Piston hole; 202. Exhaust port; 203. Oil inlet / outlet; 204. Pressure transmitter; 3. Insulated oil tank; 301. Oil inlet; 302. Heater; 303. Temperature transmitter; 4. Controller; 5. Geared linear motor; 501. Output shaft; 6. Grating ruler; 7. Piston rod. Detailed implementation method:

[0023] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0024] The following description, in conjunction with the accompanying drawings and specific embodiments, provides further details:

[0025] Example 1

[0026] like Figure 1 and Figure 2As shown, an apparatus for detecting methane content in crude oil includes a mounting frame 1, a controller 4, and a geared linear motor 5. The geared linear motor is a device that converts rotary motion into linear motion through a reduction mechanism. It uses gears, worm gears, synchronous belts, and other reduction transmission components to convert the motor's rotary motion into linear motion, simultaneously reducing speed and increasing thrust. The mounting frame 1 is equipped with a hydraulic cylinder 2 and an insulated oil tank 3. The hydraulic cylinder 2 contains a pressure transmitter 204. The insulated oil tank 3 has an annular structure and surrounds the outside of the hydraulic cylinder 2. The hydraulic cylinder 2 is designed to withstand 16 MPa, and its parameters have been verified using existing experimental methods to ensure its safety and sealing. The insulated oil tank 3 insulates the hydraulic cylinder 2, ensuring the temperature of the crude oil during methane detection. A piston hole 201 is provided at the lower end of the hydraulic cylinder 2, and a piston rod 7 is installed in the piston hole 201 through a reduction linear motor 5. A lip seal ring (contact seal) is used between the piston rod 7 and the piston hole 201. The seal is achieved through the tight contact between the lip of the seal ring and the sealing surface, which is suitable for reciprocating motion scenarios. A grating ruler 6 is provided on the mounting bracket 1 for measuring the movement distance of the piston rod 7. The reduction linear motor 5 controls the piston rod 7 to compress the crude oil in the hydraulic cylinder 2. As the pressure increases, the solubility of gas in the crude oil continuously increases, thereby causing some free gas to dissolve into the crude oil and become dissolved gas. When the saturation pressure is reached, all the free gas becomes dissolved gas and dissolves in the crude oil. Subsequent compression only compresses the liquid. The crude oil sample changes from the original two-phase gas-liquid phase to a single liquid phase. The movement distance of the piston rod 7 is detected by the grating ruler 6. During the compression process, the internal pressure can be monitored in real time by the pressure transmitter 204. The node where the gas-liquid two-phase inside the hydraulic cylinder 2 becomes a single liquid phase can be determined by the pressure and displacement change curve. The gas content in crude oil can be detected by the compression volume that produces this change node.

[0027] like Figure 1 , Figure 3 and Figure 4As shown, the mounting frame 1 is arranged from top to bottom as follows: a seating plate 101, a support leg 102, and a base 103. The seating plate 101 is mounted on the base 103 via the support leg 102. The hydraulic cylinder 2 and the insulated oil tank 3 are mounted on the seating plate 101. Multiple casters 107 are arranged sequentially along the circumference of the bottom of the base 103. The seating plate 101 also includes a through groove 106, which is formed on the seating plate 101. A piston hole 201 extends through the through groove 106 to the lower end of the seating plate 101. A first support frame 104 is provided on the base 103. A reduction linear motor 5 is mounted on the first support frame 104. The reduction linear motor 5 is provided with a linear motion output shaft 501. A piston rod 7 is provided at the upper end of the output shaft 501 and is slidably disposed in the piston hole 201. A second support frame 105 is also provided on the base 103. The grating ruler 6 is installed on the second support frame 105, and its measuring direction is parallel to the output shaft 501. The measuring component of the grating ruler 6 is connected to the shaft of the output shaft 501.

[0028] like Figure 1 , Figure 5 and Figure 6As shown, the upper end of the hydraulic cylinder 2 is provided with an exhaust port 202, and the lower end is provided with an oil inlet / outlet port 203 located in the through groove 106; both the exhaust port 202 and the oil inlet / outlet port 203 are provided with ball valve switches for opening and closing. The upper end of the heat-insulating oil tank 3 is provided with an oil filling port 301, and the interior of the heat-insulating oil tank 3 is provided with a heater 302 and a temperature transmitter 303; the oil filling port 301 is provided with a ball valve switch for opening and closing, and both the heater 302 and the temperature transmitter 303 are electrically connected to the controller 4. The controller 4 is electrically connected to the pressure transmitter 204, the geared linear motor 5, and the grating ruler 6. The heating wire of the heater 302 is usually made of a high resistivity, high temperature resistant alloy material (such as nickel-chromium alloy, iron-chromium-aluminum alloy), which has good thermal conductivity and oxidation resistance, and can work stably for a long time in high temperature environments. When the controller 4 issues a heating command, current flows through the heating wire, and due to the resistance, the current does work to generate heat. The heating wire rapidly heats up and transfers heat to the oil in the insulation tank 3 through conduction, convection, or radiation. When the CPU of the controller 4 determines that the humidity or temperature does not meet the requirements, it sends corresponding control commands to the heating wire according to the degree of deviation and a pre-programmed control program. These commands are transmitted to the heating wire as electrical signals through the controller's output interface circuit, starting or adjusting the heating wire's operating state to achieve temperature control. When the temperature transmitter 303 detects that the temperature is below a preset threshold, the controller 4 activates the heating wire circuit to start heating; when the temperature reaches the threshold, the circuit is disconnected to stop heating. For more precise temperature control, the controller 4 can adjust the input power of the heating wire using pulse width modulation (PWM) technology or a thyristor power regulator. For example, by changing the on / off time ratio (duty cycle), the average heat generation can be controlled without frequent start-stop cycles, avoiding excessive temperature fluctuations.

[0029] In actual operation, the linear motor 5 first provides power to push the piston rod 7 to compress the crude oil sample in the hydraulic cylinder 2. The pressure change in the cylinder is detected by the pressure transmitter 204 until the pressure reaches 10 MPa. During this process, the volume of the crude oil sample changes significantly with pressure as it transforms from a two-phase gas-liquid mixture to a single liquid phase. This allows for accurate determination of the volume compressed from the start of compression until it becomes a single liquid phase. The displacement of the piston is measured using a grating ruler 6 to calculate the volume of the liquid sample compressed. Finally, the gas content in the oil is calculated using a derived formula. Throughout the process, the heater 302 heats the insulating oil in the insulating oil tank 3. The temperature inside the tank is observed by the temperature transmitter 303, ensuring that the temperature remains within a certain range. After the test, the sample is discharged from the inlet / outlet 203 at the bottom. Controller 4, centered around a human-machine interface and a PLC, uses pressure transmitter 204 and temperature transmitter 303 to transmit the acquired analog signals to the PLC's external A / D conversion module. These signals are then converted to digital signals, and the PLC's data processing function obtains the accurate current temperature and pressure values, which are displayed on the host computer's human-machine interface. The movement of the grating ruler generates two-phase TTL voltage pulse signals, which are input to the PLC's high-frequency counting module to count and calculate the displacement. The PLC's output terminals are connected to the external terminals of the frequency converter, enabling functions such as controlling the motor's forward and reverse rotation and changing its speed. Finally, using the acquired data and the functions described above, ladder logic is used to program the PLC to achieve fully automated control.

[0030] Example 2

[0031] like Figure 1 and Figure 2 As shown, a device for detecting methane content in crude oil includes a mounting frame 1 and a controller 4, as well as a reduction linear motor 5. A hydraulic cylinder 2 and an insulated oil tank 3 are mounted on the mounting frame 1. A pressure transmitter 204 is installed inside the hydraulic cylinder 2. The insulated oil tank 3 has an annular structure and is arranged around the outside of the hydraulic cylinder 2. A piston hole 201 is provided at the lower end of the hydraulic cylinder 2. A piston rod 7 is installed in the piston hole 201 through the reduction linear motor 5. A grating ruler 6 for measuring the movement distance of the piston rod 7 is provided on the mounting frame 1.

[0032] like Figure 1 , Figure 3 and Figure 4As shown, the mounting frame 1 is arranged from top to bottom as follows: a seating plate 101, a support leg 102, and a base 103. The seating plate 101 is mounted on the base 103 via the support leg 102. The hydraulic cylinder 2 and the insulated oil tank 3 are mounted on the seating plate 101. Multiple casters 107 are arranged sequentially along the circumference of the bottom of the base 103. The casters 107 are casters with a self-locking structure. The seating plate 101 also includes a through groove 106, which is formed on the seating plate 101. A piston hole 201 extends through the through groove 106 to the lower end of the seating plate 101. A first support frame 104 is provided on the base 103. A reduction linear motor 5 is mounted on the first support frame 104. The reduction linear motor 5 is provided with a linear motion output shaft 501. A piston rod 7 is provided at the upper end of the output shaft 501 and is slidably disposed in the piston hole 201. A second support frame 105 is also provided on the base 103. The grating ruler 6 is installed on the second support frame 105, and its measuring direction is parallel to the output shaft 501. The measuring component of the grating ruler 6 is connected to the shaft of the output shaft 501.

[0033] like Figure 1 , Figure 5 and Figure 6 As shown, the upper end of the hydraulic cylinder 2 is provided with an exhaust port 202, and the lower end is provided with an oil inlet / outlet port 203 located in the through groove 106; both the exhaust port 202 and the oil inlet / outlet port 203 are provided with ball valve switches for opening and closing. The upper end of the heat-insulating oil tank 3 is provided with an oil filling port 301, and the interior of the heat-insulating oil tank 3 is provided with a heater 302 and a temperature transmitter 303; the oil filling port 301 is provided with a ball valve switch for opening and closing, and both the heater 302 and the temperature transmitter 303 are electrically connected to the controller 4. The controller 4 is electrically connected to the pressure transmitter 204, the reduction linear motor 5, and the grating ruler 6.

[0034] The working principle of this invention is as follows: The liquid sample enters the hydraulic cylinder 2 through the inlet / outlet 203 at the lower end. As the liquid level rises, air inside the cylinder is discharged through the exhaust port 202 at the upper end. After the liquid sample overflows from the exhaust port 202, the ball valves on both the exhaust port 202 and the inlet / outlet 203 are closed to ensure the hydraulic cylinder 2 is sealed before pressurization begins. A linear reduction motor 5 provides power to push the piston rod 7 to compress the crude oil sample inside the hydraulic cylinder 2. The pressure change inside the hydraulic cylinder 2 is detected by a pressure transmitter 204. A clear difference in volume change with pressure indicates the transition from a two-phase gas-liquid system to a single liquid phase. The displacement of the piston rod 7 is measured using a grating ruler 6, and the volume of the liquid sample compressed is calculated from this displacement. Finally, the gas content in the oil is determined. Throughout the process, a heater heats the insulating oil in the insulating oil tank 3. The temperature inside the tank is observed by a temperature transmitter 303, ensuring the temperature remains within a certain range. After the test, the sample is discharged through the inlet / outlet 203 at the lower end.

[0035] In summary, this invention pressurizes the crude oil sample in the hydraulic cylinder 2, allowing the gas in the crude oil to dissolve in the oil, thus creating a volume difference that can accurately determine the gas content in the crude oil. It eliminates the need for gas-liquid separation of the crude oil, avoiding inaccurate measurement results due to incomplete gas-liquid separation when detecting methane gas content in crude oil. Furthermore, the use of casters 107 at the bottom of the base 103 facilitates easy movement of the equipment, allowing measurement personnel to adjust its position at any time.

[0036] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. An apparatus for detecting the methane content in crude oil, comprising a mounting frame (1) and a controller (4), characterized in that, It also includes a decelerated linear motor (5); a hydraulic cylinder (2) and a heat-insulating oil tank (3) are provided on the mounting frame (1), a pressure transmitter (204) is provided inside the hydraulic cylinder (2), and the heat-insulating oil tank (3) is an annular box structure and is arranged around the outside of the hydraulic cylinder (2); a piston hole (201) is provided at the lower end of the hydraulic cylinder (2), and a piston rod (7) is provided in the piston hole (201) through the decelerated linear motor (5); a grating ruler (6) for measuring the moving distance of the piston rod (7) is provided on the mounting frame (1); the controller (4) is electrically connected to the pressure transmitter (204), the decelerated linear motor (5) and the grating ruler (6).

2. The apparatus for detecting methane content in crude oil according to claim 1, characterized in that, The mounting frame (1) is provided with a seating plate (101), a support leg (102) and a base (103) from top to bottom. The seating plate (101) is mounted on the base (103) via the support leg (102). The hydraulic cylinder (2) and the heat-insulating oil tank (3) are mounted on the seating plate (101). The bottom of the base (103) is provided with a plurality of casters (107) along its circumference.

3. The apparatus for detecting methane content in crude oil according to claim 2, characterized in that, The landing plate (101) also includes a through groove (106), on which the landing plate (101) has a through groove (106), and the piston hole (201) extends through the through groove (106) to the lower end of the landing plate (101).

4. The apparatus for detecting methane content in crude oil according to claim 3, characterized in that, The base (103) is provided with a first support frame (104), the deceleration linear motor (5) is mounted on the first support frame (104), the deceleration linear motor (5) is provided with a linear motion output shaft (501), the upper end of the output shaft (501) is provided with a piston rod (7), and the piston rod (7) is slidably disposed in the piston hole (201).

5. The apparatus for detecting methane content in crude oil according to claim 4, characterized in that, A second support frame (105) is also provided on the base (103). The grating ruler (6) is installed on the second support frame (105) and its measuring direction is parallel to the output shaft (501). The measuring component of the grating ruler (6) is connected to the shaft of the output shaft (501).

6. The apparatus for detecting methane content in crude oil according to claim 3, characterized in that, The upper end of the hydraulic cylinder (2) is provided with an exhaust port (202), and the lower end is provided with an oil inlet and outlet port (203) located in the through groove (106); both the exhaust port (202) and the oil inlet and outlet port (203) are provided with ball valve switches for opening and closing.

7. The apparatus for detecting methane content in crude oil according to claim 3, characterized in that, The upper end of the insulated oil tank (3) is provided with an oil inlet (301), and the inside of the insulated oil tank (3) is provided with a heater (302) and a temperature transmitter (303); the oil inlet (301) is provided with a ball valve switch for opening and closing, and the heater (302) and the temperature transmitter (303) are both electrically connected to the controller (4).

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