Liquid level monitoring and automatic liquid discharging device of gas-liquid separation tank

Abstract

The utility model discloses a liquid level monitoring and automatic liquid discharging device of a gas-liquid separation tank, and belongs to the technical field of gas-liquid separation. The device comprises a buffer tank, the top of the buffer tank is connected with a gas-liquid separation tank, the buffer tank is located at the bottom of the gas-liquid separation tank, the buffer tank and the gas-liquid separation tank are connected through a pipeline, the pipeline is a straight pipe and is not provided with a U-shaped bend, and liquid seal is prevented from being formed between the buffer tank and the gas-liquid separation tank; a first pressure gauge is arranged at the top of the gas-liquid separation tank, a second pressure gauge is arranged at the bottom or middle-lower part of the buffer tank, and a liquid outlet at the bottom of the buffer tank is connected with a liquid discharge regulating valve. According to the utility model, the liquid level of the gas-liquid separation tank is monitored; the monitoring on the liquid discharge effect of the gas-liquid separation tank is realized; holes do not need to be formed in the gas-liquid separation tank, so that the difficulty of modifying the gas-liquid separation tank is reduced; and automatic liquid discharge is realized.

Description

Technical Field

[0001] The utility model relates to a liquid level monitoring and automatic liquid discharging device for a gas-liquid separation tank, belonging to the technical field of gas-liquid separation. Background Technique

[0002] As a device for separating liquid phase and gas phase, the gas-liquid separation tank usually has a small volume and a low height. Usually, the gas-liquid separation tank for separating air and water is not equipped with a remote transmission and on-site liquid level gauge, and a pressure gauge is installed at the top. To drain water, the bottom drain usually needs to be opened and it is necessary to judge whether the water has been drained completely based on experience, which is not convenient for operation. Some gas-liquid separation tanks are equipped with liquid level gauges, but the liquid discharging situation at the bottom of the liquid level gauge cannot be evaluated, and it can only be handled according to operation experience.

[0003] Therefore, there is an urgent need to provide a device for monitoring the liquid level and facilitating subsequent operations. Content of the Utility Model

[0004] In order to overcome the above deficiencies, the utility model provides a liquid level monitoring and automatic liquid discharging device for a gas-liquid separation tank, which not only realizes the monitoring of the liquid discharging situation at the bottom of the gas-liquid separation tank, but also facilitates liquid discharging and reduces the operation difficulty.

[0005] The utility model uses the pressure difference to judge the liquid level height of the gas-liquid separation tank and realizes the rapid detection of whether there is liquid in the infrequently used gas-liquid separation tank; the on-site liquid discharging monitoring is realized by adding a sight glass, and at the same time, the liquid discharging effect is judged by using the pressure difference relationship. The theoretical basis of the design of the utility model is as follows: when the upper part of the gas-liquid separation tank is gas and the lower part is liquid, the liquid pressure at the bottom is higher than the gas pressure at the top; the flow of gas or liquid usually flows from high pressure to low pressure. For the same volume of liquid, there is an inverse relationship between the bottom area and the height. According to the hydrostatic pressure formula, the pressure difference is converted into a height difference to realize the monitoring of the liquid level.

[0006] The technical solution adopted by the utility model is as follows:

[0007] A liquid level monitoring and automatic liquid discharging device for a gas-liquid separation tank includes a buffer tank. The top of the buffer tank is connected to the gas-liquid separation tank, and the buffer tank is located at the bottom of the gas-liquid separation tank. The buffer tank and the gas-liquid separation tank are connected by a pipeline, and the pipeline is a straight pipe without a U-shaped bend to prevent the formation of a liquid seal between the buffer tank and the gas-liquid separation tank.

[0008] A first pressure gauge is provided at the top of the gas-liquid separation tank, a second pressure gauge is provided at the bottom or the middle and lower part of the buffer tank, and the liquid discharging outlet at the bottom of the buffer tank is connected to a liquid discharging regulating valve. When there is no liquid at the bottom of the gas-liquid separation tank and the buffer tank, the pressure difference between the two is 0; when the liquid enters the buffer tank through the gas-liquid separation tank, when the liquid level in the buffer tank submerges the pressure measuring port of the second pressure gauge, there is a pressure difference between the bottom of the buffer tank and the top of the gas-liquid separation tank shown by the pressure gauge.

[0009] When the pressure difference between the pressure gauge at the bottom of the buffer tank and the pressure gauge at the top of the gas-liquid separation tank reaches a certain value, the drain regulating valve at the bottom of the buffer tank is opened, and the drain regulating valve automatically drains. After draining for a period of time and when the pressure difference reaches the normal range, the draining is stopped. Or the pressure difference is converted into a height difference. When the height difference reaches a certain value, the drain regulating valve is opened in a chain manner, and the drain regulating valve automatically drains. After draining for a period of time, and when the height difference is within the normal range, the draining is stopped.

[0010] A drain valve is provided on the connecting pipe between the gas-liquid separation tank and the buffer tank, an air inlet valve is provided at the bottom of the gas-liquid separation tank, and a gas-liquid separation tank safety valve and an air outlet valve are provided at the top.

[0011] Connect the gas-liquid separation tank drainage sight glass to the drainage outlet of the buffer tank. The gas-liquid separation tank drainage sight glass is used to monitor when the liquid at the bottom of the buffer tank and the liquid in the gas-liquid separation tank are completely discharged. When the liquid needs to be completely discharged, first manually open the drainage regulating valve; when the liquid content in the sight glass is less than 1 / 2, the liquid at the bottom of the buffer tank and the liquid in the gas-liquid separation tank are completely discharged; when the liquid in the sight glass is greater than 1 / 2, the liquid at the bottom of the buffer tank and the liquid in the gas-liquid separation tank are not completely discharged. When the liquid is completely discharged, close the drainage regulating valve.

[0012] Specifically, the top of the buffer tank is connected to the gas-liquid separation tank at the discharge port, there is a certain height difference between the buffer tank and the gas-liquid separation tank, and the installation position of the second pressure gauge should be 0.5m~1m lower than the bottom outlet of the gas-liquid separation tank.

[0013] The automatic liquid discharge device of the gas-liquid separation tank provided by the utility model has the following beneficial effects:

[0014] (1) The utility model realizes the monitoring of the liquid level of the gas-liquid separation tank by setting a buffer tank and a liquid discharge sight glass;

[0015] (2) By setting up a pressure gauge, the drainage effect of the gas-liquid separation tank can be monitored;

[0016] (3) There is no need to drill holes in the gas-liquid separation tank, which reduces the difficulty of modifying the gas-liquid separation tank;

[0017] (4) There is a pressure difference between the bottom of the buffer tank and the top of the gas-liquid separation tank, which is interlocked with the discharge regulating valve to achieve automatic discharge; or the pressure difference is converted into a liquid level, and the liquid level is interlocked with the discharge regulating valve to achieve automatic discharge.

[0018] The utility model is further described below in conjunction with the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the utility model.

[0020] In the figure: 1 is a gas-liquid separation tank, 2 is an intake valve, 3 is an outlet valve, 4 is a first pressure gauge, 5 is a second pressure gauge, 6 is a drain valve, 7 is a sight glass for draining the gas-liquid separation tank, 8 is a safety valve for the gas-liquid separation tank, 9 is a drain regulating valve, and 10 is a buffer tank. Detailed implementation mode

[0021] Embodiment

[0022] As Figure 1 shown, a liquid level monitoring and automatic drainage device for a gas-liquid separation tank includes a buffer tank 10. The top of the buffer tank 10 is connected to the gas-liquid separation tank 1, and the buffer tank 10 is located at the bottom of the gas-liquid separation tank 1. The buffer tank 10 and the gas-liquid separation tank 1 are connected by a pipeline, and the pipeline is a straight pipe without a U-shaped bend to prevent liquid seal formation between the buffer tank and the gas-liquid separation tank.

[0023] A first pressure gauge 4 is provided at the top of the gas-liquid separation tank 1, a second pressure gauge 5 is provided at the bottom or the middle and lower part of the buffer tank 10, and a drain regulating valve 9 is provided at the bottom drain outlet of the buffer tank 10. When there is no liquid in the gas-liquid separation tank 1 and the buffer tank 10, the pressure difference between the two is 0. When the liquid enters the buffer tank through the gas-liquid separation tank, when the liquid level in the buffer tank submerges the pressure measuring port of the pressure gauge, the pressure gauge shows the pressure difference between the bottom of the buffer tank and the top of the gas-liquid separation tank.

[0024] When the pressure difference between the pressure gauge at the bottom of the buffer tank and the pressure gauge at the top of the gas-liquid separation tank reaches a certain value, open the drain regulating valve at the bottom of the buffer tank. The drain regulating valve performs automatic drainage. When the drainage lasts for a certain period and the pressure difference reaches the normal range, stop the drainage. Or convert the pressure difference into a height difference. When the height difference reaches a certain value, interlock to open the drain regulating valve. The drain regulating valve performs automatic drainage. After draining for a certain period and the height difference is within the normal range, stop the drainage.

[0025] A drain valve 6 is provided on the connecting pipeline between the gas-liquid separation tank 1 and the buffer tank 10. An intake valve 2 is provided at the bottom of the gas-liquid separation tank, and a safety valve 8 and an outlet valve 3 for the gas-liquid separation tank are provided at the top. The bottom drain outlet of the buffer tank is connected to the drain regulating valve 9.

[0026] A sight glass for draining the gas-liquid separation tank is connected to the drain outlet of the buffer tank. The sight glass 7 for draining the gas-liquid separation tank is used to monitor when the liquid at the bottom of the buffer tank and the liquid in the gas-liquid separation tank are all drained. When all the liquid needs to be drained, first manually open the drain regulating valve 9. When the liquid content in the sight glass is less than 1 / 2, then the liquid at the bottom of the buffer tank and the liquid in the gas-liquid separation tank are all drained. When the liquid in the sight glass is greater than 1 / 2, then the liquid at the bottom of the buffer tank and the liquid in the gas-liquid separation tank are not all drained. After all the liquid is drained, close the drain regulating valve 9.

[0027] The specific operation method is as follows:

[0028] (1) Connect the top of the buffer tank to the liquid discharge port of the gas-liquid separation tank. There is a certain height difference between the buffer tank and the gas-liquid separation tank. The installation position of the second pressure gauge 5 should be 0.5 m to 1 m lower than the bottom outlet of the gas-liquid separation tank.

[0029] (2) A second pressure gauge is provided at the bottom or the middle and lower part of the buffer tank, and a first pressure gauge is provided at the top of the gas-liquid separation tank.

[0030] (3) The liquid discharge port at the bottom of the buffer tank is connected to a liquid discharge regulating valve.

[0031] (4) When there is liquid at the bottom of the buffer tank and when the liquid level in the buffer tank submerges the pressure measuring port of the pressure gauge, there is a pressure difference between the bottom of the buffer tank and the top of the gas-liquid separation tank shown by the pressure gauge. Establish a linkage with the liquid discharge regulating valve through the pressure difference to achieve automatic liquid discharge. Or convert the pressure difference into a liquid level and establish a linkage with the liquid discharge regulating valve through the liquid level to achieve automatic liquid discharge.

[0032] The implementation process of the present utility model will be described below through specific embodiments:

[0033] In the on-site drainage of the air compressor gas-liquid separation tank in a chemical plant, there is no on-site liquid level gauge for the gas-liquid separation tank. Whether the liquid is drained cleanly needs to be judged based on experience during on-site liquid discharge. Due to differences in operating levels, the liquid discharge effects vary. If the amount of water discharged from the gas-liquid separation tank every day is less than the amount of water separated by the gas-liquid separation tank, the liquid in the gas-liquid separation tank will become more and more, eventually causing the air compressor to start and stop frequently, affecting normal operation. Because the chemical plant cannot detect the liquid discharge, after long-term operation, the gas-liquid separation tank is full of water, affecting the operation of the air compressor. After the transformation using the present utility model, the monitoring of the liquid discharge effect and automatic liquid discharge are realized through the pressure difference.

[0034] As Figure 1 shown, the operating pressure of the gas-liquid separation tank 1 is higher than the atmospheric pressure. The air inlet of the gas-liquid separation tank is set at the low point, the gas outlet valve 3 is at the highest point at the top of the gas-liquid separation tank 1, and the liquid discharge port is at the bottom of the gas-liquid separation tank. The gas-liquid mixture enters the gas-liquid separation tank 1, the liquid falls to the bottom of the gas-liquid separation tank, and the gas is discharged from the top; when the gas-liquid separation tank is operating, the intake valve 2 and the outlet valve 3 of the gas-liquid separation tank are in the open state;

[0035] The first pressure gauge 4 of the gas-liquid separation tank is generally installed at the top of the gas-liquid separation tank for monitoring the pressure of the gas-liquid separation tank; a buffer tank 10 is added below the gas-liquid separation tank 1, and a second pressure gauge 5 is provided at the bottom of the buffer tank 10 for comparison with the first pressure gauge 4 to judge whether there is liquid at the bottom of the gas-liquid separation tank and whether liquid discharge is required. The installation position of the second pressure gauge 5 should be 0.5 m to 1 m lower than the bottom outlet of the gas-liquid separation tank, which is convenient for judging whether liquid discharge is required.

[0036] The liquid discharge valve 6 at the bottom of the gas-liquid separation tank is in the normally open state.

[0037] The liquid discharge sight glass 7 of the gas-liquid separation tank is used to assist personnel in monitoring the liquid discharge situation and can be installed according to actual conditions. The safety valve 8 of the gas-liquid separation tank is used for discharging overpressure gas.

[0038] The above-mentioned liquid discharge regulating valve 9 can be manually controlled or automatically controlled. When the pressure difference between the second pressure gauge 5 and the first pressure gauge 4 is large, the liquid discharge regulating valve 9 is opened.

[0039] Further description of the above device:

[0040] I. Selection of pressure gauges

[0041] For the first pressure gauge 4 and the second pressure gauge 5, the selected accuracy class of the pressure gauge should be high. Otherwise, it will cause errors in the instrument itself and lead to deviations in judging whether there is liquid.

[0042] If a pressure gauge with a low pressure grade is selected, when the pressure gauge measures the same pressure, the absolute pressure should be relatively small. Otherwise, it is impossible to judge whether there is liquid through the pressure.

[0043] II. Criteria for judging whether there is liquid and the amount of liquid

[0044] When there is liquid in the gas-liquid separation tank, the pressure of the second pressure gauge 5 is higher than that of the first pressure gauge 4. When the bottom of the gas-liquid separation tank is the same substance, the greater the pressure difference between the upper and lower pressure gauges, the higher the liquid level. When the liquid at the bottom of the gas-liquid separation tank is more than two substances and the substances are compatible and the density is stable, the greater the pressure difference between the upper and lower pressure gauges, the higher the liquid level. When the liquid at the bottom of the gas-liquid separation tank is more than two substances and the substances are incompatible, it is described in the following three cases: ① When the pressure difference is constant, the height of the liquid level depends on the amount of the substance; ② When the pressure is constant and the volume of the high-density substance is large, the liquid level is low; ③ When the pressure is constant and the volume of the low-density substance is large, the liquid level is high.

[0045] The height of the liquid at the bottom of the gas-liquid separation tank can be calculated through the hydrostatic pressure calculation formula. For the convenience of operation, the pressure difference can be converted into a height difference, and the conversion formula is as follows:

[0046]

[0047] In the formula: P5 represents the pressure shown at the second pressure gauge 5, with the unit of Pa;

[0048] P4 represents the pressure shown at the first pressure gauge 4, with the unit of Pa;

[0049] ρ 液 represents the density of the liquid at the bottom of the gas-liquid separation tank, with the unit of kg / m³;

[0050] g represents the acceleration of gravity, generally taken as 9.81 N / kg;

[0051] h represents the vertical distance from the bottom outlet of the gas-liquid separation tank to the second pressure gauge 5, with the unit of m;

[0052] H represents the actual liquid level height in the gas-liquid separation tank, with the unit of cm;

[0053] When calculating H=- h, it means that there is no liquid at the bottom of the gas-liquid separation tank 1 and no liquid at the position of the second pressure gauge 5 installed in the buffer tank;

[0054] When calculating - h﹤ H ﹤0, it means that there is no liquid at the bottom of the gas-liquid separation tank 1, there is liquid at the position of the second pressure gauge 5 installed in the buffer tank, and the buffer tank 10 is not full;

[0055] When calculating H=0 it means that there is no liquid at the bottom of the gas-liquid separation tank 1, there is liquid at the position of the second pressure gauge 5 installed in the buffer tank, and the buffer tank 10 is full of liquid;

[0056] When calculating H﹥0 it means that there is liquid at the bottom of the gas-liquid separation tank 1, there is liquid at the position of the second pressure gauge 5 installed in the buffer tank, and the buffer tank 10 is full of liquid;

[0057] III. Influence of liquid density on judging the liquid level height

[0058] When the liquid level is constant, different liquid densities will result in different pressure differences. The pressure difference is related to the liquid density and the liquid level height. When the liquid level is constant, the density and the pressure difference are in a direct proportion relationship, and the pressure difference between the upper and lower pressure gauges will be affected by the pressure.

[0059] IV. Liquid drainage conditions

[0060] When the pressure of the first pressure gauge 4 is greater than the atmospheric pressure, it is necessary to select whether to collect according to the material properties. When the pressure of the first pressure gauge 4 is less than the atmospheric pressure, liquid cannot be drained locally, otherwise air will enter the gas-liquid separation tank, and the liquid drainage needs to be designed separately.

[0061] V. Setting of automatic liquid drainage interlock

[0062] When there is liquid at the second pressure gauge 5, the pressure of the second pressure gauge 5 is greater than the pressure of the first pressure gauge 4, and it is impossible to directly judge the liquid height. The pressure difference between the second pressure gauge 5 and the first pressure gauge 4 is converted into a height difference, and the interlock liquid level is assumed to be L;

[0063] ① When the interlock liquid drainage is required when there is no liquid in the gas-liquid separation tank 1 and the buffer tank 10 is not full, the value range of L is set as - h < A1 < 0. When the height H ≥ L, the interlock opens the liquid drainage regulating valve 9 of the gas-liquid separation tank for liquid drainage.

[0064] ②When the liquid in the gas-liquid separation tank 1 needs to be drained in interlock when there is no liquid in the gas-liquid separation tank 1 and the buffer tank 10 is full of liquid, the value of L is equal to 0. When the height H≥L, the gas-liquid separation tank drain regulating valve 9 is opened in interlock for drainage.

[0065] ③When the gas-liquid separation tank 1 needs to drain with a certain liquid level, at this time the buffer tank 10 is full of liquid, the value of L is greater than 0. When the measured height H≥L, the gas-liquid separation tank drain regulating valve 9 is opened in interlock for drainage.

[0066] When the liquid level value is not used as the interlock, when the differential pressure is used as the interlock, the differential pressure △P is set according to the need, △P = P5 - P4 for interlock, and the height value is converted into a height difference through the differential pressure.

Claims

1. A liquid level monitoring and automatic liquid discharging device for a gas-liquid separation tank, characterized in that: It includes a buffer tank. The top of the buffer tank is connected to a gas-liquid separation tank, and the buffer tank is located at the bottom of the gas-liquid separation tank. The buffer tank and the gas-liquid separation tank are connected by a pipeline, and the pipeline is a straight pipe without a U-bend to prevent liquid seal formation between the buffer tank and the gas-liquid separation tank. A first pressure gauge is provided at the top of the gas-liquid separation tank, and a second pressure gauge is provided at the bottom or the middle and lower part of the buffer tank. The liquid discharge outlet at the bottom of the buffer tank is connected to a liquid discharge regulating valve.

2. The liquid level monitoring and automatic liquid discharging device for the gas-liquid separation tank according to claim 1, wherein: A liquid discharge valve is provided on the connecting pipeline between the gas-liquid separation tank and the buffer tank. An intake valve is provided at the bottom of the gas-liquid separation tank, and a gas-liquid separation tank safety valve and an outlet valve are provided at the top.

3. The liquid level monitoring and automatic liquid drainage device for the gas-liquid separation tank according to claim 1, characterized in that: Connect the buffer tank top at the liquid discharge port of the gas-liquid separation tank. The installation position of the second pressure gauge should be 0.5 m to 1 m lower than the bottom outlet of the gas-liquid separation tank.

4. The liquid level monitoring and automatic liquid discharging device for the gas-liquid separation tank according to claim 1, characterized in that: Connect the liquid discharge sight glass of the gas-liquid separation tank at the liquid discharge outlet of the buffer tank for monitoring when all the liquid at the bottom of the buffer tank and the liquid in the gas-liquid separation tank are discharged.

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