A method for on-line monitoring of solid-liquid level of a desanding tank

Abstract

The application provides a solid-liquid level online monitoring method of a sand removal tank to solve the problem that the solid-liquid level of the sand removal tank cannot be monitored online and relates to the technical field of natural gas and shale gas. The solid-liquid level online monitoring method of the sand removal tank comprises the following steps: multiple temperature measuring points are arranged on the outside of the tank wall of the sand removal tank along the height direction; a heating device is used to heat each temperature measuring point; the temperature of each temperature measuring point is measured; and the solid-liquid level of the sand removal tank is determined according to the measured temperature of each temperature measuring point. The method can accurately determine the solid-liquid level of the sand removal tank online, and is convenient for timely sand and liquid discharge of the sand removal tank.

Description

Technical Field

[0001] This invention relates to the field of natural gas and shale gas technology, and specifically to a method for online monitoring of solid and liquid levels in a sand removal tank. Background Technology

[0002] Currently, the main production process for natural gas and shale gas wellheads involves desanding followed by gas-liquid separation, and then metering and export. The desanding process primarily employs filter-type or cyclone-type desanding tanks to remove sand particles from the gas-liquid two-phase mixture. The desanded gas-liquid mixture then enters a conventional gravity separator for further gas-liquid separation. Because the high-speed movement of sand particles in pipelines and equipment causes severe erosion and corrosion to production facilities, potentially leading to perforation of pipes or valves, it is necessary to periodically drain the sand and liquid from the desander to prevent them from entering downstream pipelines. However, due to the high operating pressure of the equipment, the high-speed erosion of sand particles on the inner walls of the drain pipes and elbows during sand discharge can exacerbate wall thinning and even perforation. Furthermore, the amount of sand and liquid produced is typically large in the early stages of production, decreasing irregularly and without a fixed pattern during the middle stages, making it impossible to discharge based on experience. Therefore, online monitoring of the solid-liquid level inside the desander is crucial for accurately determining the solid-liquid level in the desander tank and ensuring timely discharge.

[0003] However, due to the high pressure of natural gas inside the desanding tank, installing solid or liquid level monitoring devices in the sand-liquid storage area is not only extremely inconvenient but also difficult to maintain. Traditional level gauges can only measure liquid level and not the solid phase. Therefore, current desanding tanks typically do not have online solid-liquid level monitoring devices, resulting in the inability to monitor solid and liquid levels online. Consequently, in daily production, the separated materials are usually only periodically removed and cleaned based on production experience, making timely discharge difficult and potentially causing adverse effects on production or equipment. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an online solid-liquid level monitoring method for a sand removal tank, so as to solve the problem of the inability to monitor the solid-liquid level of the sand removal tank online.

[0005] The technical solution adopted by this invention to solve its technical problem is: an online solid-liquid level monitoring method for a sand removal tank, the method comprising:

[0006] Multiple temperature measuring points are set along the height direction on the outer side of the sand removal tank wall;

[0007] Each temperature measuring point is heated using a heating device;

[0008] Measure the temperature at each measuring point;

[0009] The solid-liquid level of the sand removal tank is determined by measuring the temperature at each temperature measuring point.

[0010] Furthermore, a heating device is used to heat each temperature measuring point simultaneously for the same amount of time.

[0011] Furthermore, the temperature measuring points are arranged on the same vertical line.

[0012] Furthermore, the temperature measuring points are all distributed along the same vertical line.

[0013] Furthermore, the outer side of the sand removal tank is provided with a scale bar, which is located on one side of the temperature measuring point.

[0014] Furthermore, a vertically arranged heating wire is provided on the outer side of the sand removal tank wall as a heating device for heating each temperature measuring point.

[0015] Furthermore, the temperature at each measurement point was measured using an infrared imager.

[0016] The beneficial effects of this invention are:

[0017] 1. The present invention provides an online solid-liquid level monitoring method for a sand removal tank. By setting temperature measuring points and heating devices on the outside of the sand removal tank wall, and taking advantage of the different heat transfer capabilities and heat capacities of different media, the solid-liquid level of the sand removal tank can be accurately determined online based on the temperature of each measuring point, which facilitates timely sand and liquid discharge from the sand removal tank.

[0018] 2. This method is a non-invasive detection method. The equipment does not enter the pressure vessel for detection. It is easy to operate and train, and will not affect production. Attached Figure Description

[0019] Figure 1 This is a flowchart of an online solid-liquid level monitoring method for a sand removal tank according to the present invention;

[0020] Figure 2 This is a schematic diagram of the temperature measuring point setting of a sand removal tank according to an embodiment of the present invention;

[0021] Figure 3 This is a schematic diagram of the temperature measuring point setting of a sand removal tank according to an embodiment of the present invention;

[0022] The diagram shows: sand removal tank 1, heating device 2, scale bar 3, temperature measuring point 11, solid-liquid boundary line 12, and liquid-gas boundary line 13. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0024] like Figures 1 to 2 As shown, the present invention provides an online solid-liquid level monitoring method for a sand removal tank, the method comprising:

[0025] Step 1: Set multiple temperature measuring points 11 along the height direction on the outer side of the sand removal tank 1;

[0026] Step 2: Use heating device 2 to heat each temperature measuring point 11;

[0027] Step 3: Measure the temperature at each temperature measuring point 11;

[0028] Step 4: Determine the solid-liquid level of the sand removal tank based on the measured temperatures at each temperature measuring point 11.

[0029] The material inside the sand removal tank is distributed from bottom to top in the order of solid phase (sand), liquid phase (water), and gas phase. The thermal conductivity and heat capacity of these three phases differ significantly. After heating each temperature measuring point 11 by the heating device 2, the temperature rise of each measuring point 11 within each phase region will be different. Therefore, by measuring the temperature of each measuring point 11, the solid-liquid level of the sand removal tank can be determined online based on the measured temperatures. Specifically, if the heating device 2 heats each temperature measuring point 11 for the same time, the solid-liquid level can be determined directly based on the measured temperatures of each measuring point 11. If the heating device 2 heats each temperature measuring point 11 for different times, the temperature rise rate of each measuring point is calculated based on the measured temperatures, and the solid-liquid level can then be determined based on the temperature rise rate of each measuring point. Since the initial temperature of each temperature measuring point 11 is the same, which is the ambient temperature, the temperature rise rate V of the temperature measuring point 11 can be simplified as: V = S / t, where S is the temperature of the measured temperature measuring point and t is the heating time.

[0030] The specific methods for determining solid and liquid levels are as follows:

[0031] Taking the heating time of each temperature measuring point 11 by the heating device 2 as an example, the temperature rise rate of the two temperature measuring points 11 adjacent to the solid-liquid boundary line 12 and the two temperature measuring points 11 adjacent to the liquid-gas boundary line 13 will have obvious differences. Therefore, from bottom to top, the height of the solid phase in the sand removal tank is between the two temperature measuring points with the larger temperature rise rate in the first pair, and the height of the liquid phase is between the two temperature measuring points with the larger temperature rise rate in the second pair.

[0032] This monitoring method does not require the equipment to enter the desanding tank during online monitoring, making it easy to operate and allowing for uninterrupted production. Furthermore, the method's operating principle is simple, unaffected by the internal pressure of the desanding tank, and its conclusions are reliable.

[0033] For ease of comparison, it can be understood that during the heating process of heating device 2 to each temperature measuring point 11, the amount of heat transferred by heating device 2 to each temperature measuring point 11 per unit time is equal or approximately equal.

[0034] In this invention, heating of each temperature measuring point 11 can be performed simultaneously or separately, preferably simultaneously with the same heating time, which is more accurate.

[0035] In this invention, the temperature measuring points 11 are arranged on the same vertical line. Of course, the temperature measuring points 11 may not be arranged on the same vertical line, but this method has the problem of inconvenience in temperature measurement compared with the first method.

[0036] In some embodiments, the temperature measuring points 11 are evenly distributed along the same vertical line. In some embodiments, the temperature measuring points 11 are not evenly distributed along the same vertical line.

[0037] To facilitate reading the solid and liquid phase heights, in this invention, a scale bar 3 is provided on the outer side of the sand removal tank 1, and the scale bar 3 is located on one side of the temperature measuring point 11. Thus, by determining the solid-liquid boundary line 12 and the liquid-gas boundary line 13, the values ​​on the scale bar 3 of the sand removal tank can be obtained.

[0038] Within the same height range, the more temperature measuring points there are, the more accurate the detection of solid and liquid levels. When the spacing between temperature measuring points is infinitely close, the measuring points form a temperature measuring band (see...). Figure 3 Each temperature measuring point 11 can be equipped with an independent heating device, that is, each temperature measuring point is equipped with an independent heating device (see...). Figure 2 In one embodiment of the present invention, as follows: Figure 3 As shown, a vertically arranged heating wire 4 is provided on the outer side of the desanding tank 1 as a heating device 2 for heating each temperature measuring point 11. Using a single heating wire 4 to heat each temperature measuring point 11 can ensure that the heat transfer to each temperature measuring point 11 is equal or approximately equal per unit time, and the heating operation is more convenient. Specifically, the heating wire 4 can be installed on the tank wall of the desanding tank 1 by welding, bolting, snap-fitting, or other methods.

[0039] This invention can measure the temperature of each measuring point 11 using an infrared thermometer, infrared imager, etc. When all measuring points 11 are evenly distributed on the same vertical line, there will be a significant rate of temperature rise on both sides of the liquid-gas boundary 13 and the solid-liquid boundary 12. When observing the sand removal tank with an infrared imager, the solid and liquid levels in the sand removal tank can be directly determined by the image color of the infrared imager, which is faster.

Claims

1. A method for on-line monitoring of solid-liquid level of a desanding tank, characterized in that, The method comprises: a plurality of temperature measuring points (11) are arranged along the height direction outside the tank wall of the desanding tank (1); each temperature measuring point (11) is heated by a heating device (2); the temperature of each temperature measuring point (11) is measured; the solid-liquid level of the desanding tank is determined according to the measured temperature of each temperature measuring point (11); when the heating time of the heating device (2) on each temperature measuring point (11) is different, the temperature rising rate of each temperature measuring point is calculated according to the measured temperature of each temperature measuring point (11), and from bottom to top, the height of the solid phase in the desanding tank is between the two temperature measuring points with a larger temperature rising rate in the first pair of temperature measuring points, and the height of the liquid phase is between the two temperature measuring points with a larger temperature rising rate in the second pair of temperature measuring points; when the heating time of the heating device (2) on each temperature measuring point (11) is the same, from bottom to top, the height of the solid phase in the desanding tank is between the two temperature measuring points with a larger temperature difference in the first pair of temperature measuring points, and the height of the liquid phase is between the two temperature measuring points with a larger temperature difference in the second pair of temperature measuring points.

2. The method for on-line monitoring of solid-liquid level of a desanding tank according to claim 1, characterized in that, Each temperature measuring point (11) is heated by the heating device (2) for the same time.

3. The method for on-line monitoring of solid-liquid level of a desanding tank according to claim 1, characterized in that, The temperature measuring points (11) are arranged on the same vertical line.

4. The method for on-line monitoring of solid-liquid level of a desanding tank according to claim 3, characterized in that, The temperature measuring points (11) are evenly arranged on the same vertical line.

5. The method for on-line monitoring of solid-liquid level of a desanding tank according to claim 4, characterized in that, A scale bar (3) is arranged outside the tank wall of the desanding tank (1), and the scale bar (3) is arranged on one side of the temperature measuring points (11).

6. The method for on-line monitoring of solid-liquid level of a desanding tank according to claim 4, characterized in that, A vertical electric heating wire (4) is arranged outside the tank wall of the desanding tank (1) as the heating device (2) for heating each temperature measuring point (11).

7. The method of claim 1, wherein the method comprises: determining the solid-liquid level of the desanding tank by using the ultrasonic sensor and the infrared sensor. An infrared imager is used to measure the temperature of each temperature measuring point (11).

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