Three-phase liquid level interface detection device of electric desalting tank and electric desalting tank

Abstract

The utility model relates to a three-phase liquid level interface detection device of an electric desalting tank and the electric desalting tank. The three-phase liquid level interface detection device comprises at least two viscosity sensors arranged in the electric desalting tank, wherein the arrangement positions of the viscosity sensor at least comprise a first detection position located between an oil distribution pipe and a water flushing pipe in the electric desalting tank and a second detection position located between the oil distribution pipe and the water flushing pipe in the electric desalting tank; and the second detection position is positioned below the water flushing pipe in the electric desalting tank. According to the three-phase liquid level interface detection device for the electric desalting tank, three-phase liquid level interface detection is achieved based on the viscosity difference principle of oil, water and emulsified liquid, the oil content in water of a setting layer can be monitored in time through arrangement of the viscosity sensor, and therefore the purpose that the oil-water separation effect does not need to be prepared and judged through manual on-site recheck is achieved. The problems that the manual sampling observation result lags behind interface control in the tank, organic gas is discharged disorderly in the sampling process, and toxic and harmful components in a medium may cause occupational health injury to operators are solved.

Description

Technical Field

[0001] The utility model relates to a three-phase liquid level interface detection device for an electric desalting tank and an electric desalting tank. Background Art

[0002] The electric desalting device is an essential device in a refinery enterprise. Accurately controlling the oil-water interface of the electric desalting tank is an important guarantee for the stable operation of the atmospheric and vacuum distillation unit. If the oil-water interface is too high, it will cause the desalted crude oil to carry water, resulting in tower flooding accidents in the pre-fractionating tower, increased power consumption, and waste of water resources. If the oil-water interface is too low, it will cause an increase in the oil content of the discharged sewage, increasing the difficulty of subsequent oily and saline sewage treatment and significantly increasing the sewage treatment cost. Even oil leakage accidents and environmental protection accidents where the discharged sewage does not meet the standards may occur. Therefore, controlling the oil-water interface of the desalting tank is an important factor to ensure the normal operation of the device.

[0003] Most of the oil-water interface detection sensors equipped in existing electric desalting devices are instruments based on electromagnetic principles such as radio frequency admittance and microwave. Changes in crude oil varieties, salt content in oil and water, and the form of sewage emulsification will cause the level meters to be inaccurate, making it difficult to accurately and stably detect the oil-water separation situation. To avoid production anomalies caused by sensor errors, most domestic enterprises adopt the method of manually discharging media from different height discharge ports at regular intervals on-site, and observing the oil-water condition of the media by the naked eye to check and determine the oil-water interface in the tank, providing a basis for controlling the oil-water interface in the tank. This operation method is backward, with a large labor intensity, potential safety hazards, and unordered emissions of organic gases during the sampling process. The toxic and harmful components in the media may cause occupational health damage to operators. Summary of the Utility Model

[0004] The first object of the utility model is to provide a three-phase liquid level interface detection device for an electric desalting tank.

[0005] To achieve the above object, the utility model adopts the following technical solutions:

[0006] A three-phase liquid level interface detection device for an electric desalting tank, comprising at least two viscosity sensors arranged in the electric desalting tank;

[0007] Among them, the arrangement positions of the viscosity sensors at least include:

[0008] A first detection position between the oil distribution pipe and the water flushing pipe in the electric desalting tank; and

[0009] A second detection position below the water flushing pipe in the electric desalting tank.

[0010] As a preferred embodiment, the arrangement position of the viscosity sensor further includes a third detection position between the electrode plate and the oil distribution pipe above the first detection position.

[0011] As a preferred embodiment, the installation position of the viscosity sensor further includes a fourth detection position below the second detection position and above the sewage discharge pipe.

[0012] As a preferred embodiment, the first detection position is 1-2 cm above the water flushing pipe in the electro - desalting tank;

[0013] The second detection position is 1-5 cm below the water flushing pipe in the electro - desalting tank.

[0014] As a preferred embodiment, the third detection position is below the electrode plate in the electro - desalting tank and 2-4 cm above the oil distribution pipe;

[0015] The fourth detection position is below the third detection position in the electro - desalting tank and 1-5 cm above the sewage discharge pipe.

[0016] As a preferred embodiment, the viscosity sensor is a vibrating - type viscosity sensor. The principle of the vibrating - type on - line viscometer is that the sensor probe makes an amplitude motion at a certain frequency in the fluid. Due to the action of the fluid viscous damping, the amplitude of the probe will decay. By supplementing the energy lost due to the fluid viscous damping to keep the amplitude of the probe in the state before the interaction with the fluid, this part of the supplemented energy is related to the viscosity of the fluid. Measuring this part of the supplemented energy, the viscosity of the fluid can be calculated according to a certain relationship. Therefore, when measuring the viscosities of each layer in the electro - desalting tank, since the viscosity values of the water layer, the emulsion layer and the oil layer vary greatly, using a vibrating - type viscometer, according to the size of the supplemented amplitude energy, the position of the water layer can be directly reflected.

[0017] As a preferred embodiment, the installation direction of the viscosity sensor is perpendicular to the liquid flow direction.

[0018] As a preferred embodiment, the output signal of the viscosity sensor is sent to the DCS system through a signal collector.

[0019] Further, the signal output end of the DCS system is connected to the valve of the sewage discharge pipe to control the opening and closing of the valve.

[0020] The second object of the present invention is to provide an electro - desalting tank, in which the above - mentioned three - phase liquid level interface detection device for the electro - desalting tank is provided.

[0021] The three-phase liquid level interface detection device of the electric desalting tank of the present utility model realizes the detection of the three-phase liquid level interface based on the principle of the viscosity difference of oil, water, and emulsion. Through the arrangement of viscosity sensors, the oil content in the water of the set layer can be monitored in a timely manner, so as to achieve the purpose of judging the oil-water separation effect without manual on-site review. It avoids the problems that the result of manual sampling observation lags behind the interface control in the tank and the disordered emission of organic gases during the sampling process, and the possible occupational health hazards caused by toxic and harmful components in the medium to the operators. Brief Description of the Drawings

[0022] Figure 1 It is a schematic diagram of the three-phase liquid level interface detection device of the electric desalting tank of the present utility model.

[0023] In the figure, 1 is an electric desalting tank; 2 is an electrode plate; 3 is an oil distribution pipe; 4 is a water flushing pipe; 5 is a sewage cut-off pipe; 6 is a signal collector; 7 is a DCS system; 8 is a valve; 91 is the first detection position; 92 is the second detection position; 93 is the third detection position; 94 is the fourth detection position. Specific Embodiments

[0024] The technical solution of the present utility model will be further elaborated below in conjunction with the description of the drawings and specific embodiments.

[0025] Embodiment 1

[0026] As Figure 1 shown in the electric desalting tank 1, a number of viscosity sensors are arranged in the tank body, including viscosity sensors located at the first detection position 91 and the second detection position 92 respectively.

[0027] The installed viscosity sensors can be connected through the bottom drainage line of the tank. The sensors are connected to the drainage line pipeline with flanges. Preferably, the installation direction of the viscosity sensors is perpendicular to the liquid flow direction.

[0028] The first detection position 91 is located between the oil distribution pipe 3 and the water flushing pipe 4, and the second detection position 92 is located below the water flushing pipe 4 in the electric desalting tank. Preferably, the first detection position 91 is 1-2 cm above the water flushing pipe 4 in the electric desalting tank 1 and needs to be kept below the electrode plate 2; the second detection position 92 is 1-5 cm below the water flushing pipe 4 in the electric desalting tank 1 and needs to be above the sewage cut-off pipe 5.

[0029] The output signal of the viscosity sensor is input into the DCS system 7 of the electric desalting tank through the signal collector 6. Based on the existing principle that viscosity: crude oil > emulsion zone > water, the area where the corresponding viscometer is located can be judged as the water zone, emulsion zone, or oil zone based on the measured value of the viscosity sensor. The DCS system is a common system for valve control. The output signal of the DCS system can be connected to the valve to control the opening and closing and the opening degree of the valve. It can also adjust the valve by itself according to the measured viscosity value.

[0030] In this embodiment, the viscosity sensor is a vibrating viscosity sensor.

[0031] Embodiment 2

[0032] In this embodiment, viscosity sensors are also arranged at the third detection position 93 between the electrode plate 2 and the oil distribution pipe 3 above the first detection position 91 in the electric desalting tank 1, and at the fourth detection position above the sewage discharge pipe 5 below the second detection position 92. Preferably, the third detection position 93 is located below the electrode plate 2 in the electric desalting tank and 2-4 cm above the oil distribution pipe 3; the fourth detection position 94 is located below the third detection position 93 in the electric desalting tank 1 and 1-5 cm above the sewage discharge pipe 5.

[0033] At the third detection position 93 close to the electrode plate, the interface level can be confirmed whether it is close to the electrode plate according to the viscosity measured at the third detection position 93, and the valve can be adjusted in time for interface level control to avoid causing short circuit of the electrode plate. The fourth detection position 94 is close to the sewage discharge pipe 5. Whether the oil content in the sewage increases can be determined according to the viscosity value here, and whether to adjust the valve to control the interface level can be judged according to the viscosity value at the fourth detection position 94.

Claims

1. A three-phase liquid level interface detection device for an electric desalting tank, characterized in that, Comprising at least two viscosity sensors disposed inside the electro - desalting tank; Among them, the installation positions of the viscosity sensors at least include: A first detection position between the oil distribution pipe and the water flushing pipe inside the electro - desalting tank; and A second detection position below the water flushing pipe inside the electro - desalting tank.

2. The device according to claim 1, wherein The installation position of the viscosity sensor further includes a third detection position between the electrode plate and the oil distribution pipe, above the first detection position.

3. The device according to claim 1, characterized in that, The installation position of the viscosity sensor further includes a fourth detection position between the sewage discharge pipe and above the sewage cut - off pipe, below the second detection position.

4. The device according to claim 1, characterized in that, The first detection position is 1 - 2 cm above the water flushing pipe inside the electro - desalting tank; The second detection position is 1 - 5 cm below the water flushing pipe inside the electro - desalting tank.

5. The device according to claim 2, wherein, The third detection position is 2 - 4 cm above the oil distribution pipe and below the electrode plate inside the electro - desalting tank.

6. The device according to claim 3, characterized in that The fourth detection position is 1 - 5 cm above the sewage cut - off pipe and below the third detection position inside the electro - desalting tank.

7. The device according to claim 1, characterized in that, The viscosity sensor is a vibrating - type viscosity sensor.

8. The device according to claim 1, characterized in that, The installation direction of the viscosity sensor is perpendicular to the liquid flow direction.

9. The device according to claim 1, characterized in that, The output signal of the viscosity sensor is sent to the DCS system through a signal collector.

10. The device according to claim 9, characterized in that, The signal output end of the DCS system is connected to the valve of the sewage discharge pipe to control the opening and closing and the opening degree of the valve.

11. An electric desalting tank, characterized in that, The electro - desalting tank is provided with the three - phase liquid level interface detection device of the electro - desalting tank according to any one of claims 1 - 10.

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