Heavy oil storage tank dehydration system

Abstract

The invention discloses a dehydration system of a heavy oil storage tank. The dehydration system solves the problem that water in a heavy oil storage tank with heavy oil density larger than water density cannot be removed in the prior art. Comprising a heavy oil storage tank, a dehydration oil scavenger pump and a three-way diverter valve, at least three dehydration valves are sequentially arranged on the heavy oil storage tank from the upper portion to the lower portion of the tank, an inlet of the dehydration oil scavenger pump is connected with an outlet of a pump inlet pipeline of a dehydration pipe, and the heavy oil storage tank is communicated with an inlet of the pump inlet pipeline of the dehydration pipe through the dehydration valves at different positions on the heavy oil storage tank. The three-way diverter valve comprises a three-way diverter valve inlet, a three-way diverter valve first outlet and a three-way diverter valve second outlet, the dehydration oil return pump outlet is connected with the three-way diverter valve inlet through a pump outlet pipeline of the dehydration pipe, and the three-way diverter valve first outlet is connected with the drainage pipeline; a second outlet of the three-way diverter valve is connected with the heavy oil storage tank through an oil return pipeline, a tank inlet valve is arranged on the oil return pipeline, and a flow meter, a first water content analyzer and a second water content analyzer are sequentially arranged on a pump outlet pipeline of the dewatering pipe in the direction from the dewatering oil return pump to an inlet of the three-way diverter valve.

Description

Technical Field

[0001] This invention belongs to the field of oil storage and transportation safety technology for petrochemical enterprises, and specifically relates to a dehydration system for heavy oil storage tanks. Background Technology

[0002] Currently, the density of most petroleum and its distillate fractions is less than that of water. In these oil storage tanks, water is located at the bottom of the tank, and is removed through a dehydration pipe at the bottom. However, the proportion of heavy and low-quality petroleum is increasing, especially the proportion of heavy fractions in crude oil. These heavy oils have a high density, some with a specific gravity greater than 1.0. This causes water to rise to the top of the heavy oil. When the tank level rises above the height of the dehydration pipe, water cannot be removed through it, accumulating inside the heavy oil tank. This not only reduces the effective storage capacity of the heavy oil tank but also wastes heating steam and increases the risk of corrosion. Currently, there is no effective method for removing water from heavy oil storage tanks with a density greater than water. Summary of the Invention

[0003] The purpose of this invention is to provide a dehydration system for heavy oil storage tanks, so as to overcome the shortcomings of existing technologies, such as the inability to remove water from heavy oil storage tanks where the density of heavy oil is greater than that of water.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A heavy oil storage tank dehydration system includes a heavy oil storage tank, characterized in that: the heavy oil storage tank dehydration system further includes a dehydration return oil pump and a three-way diverter valve; at least three dehydration valves are sequentially arranged from the top to the bottom of the heavy oil storage tank; the inlet of the dehydration return oil pump is connected to the outlet of the pump inlet pipe of the dehydration pipe; the heavy oil storage tank is connected to the inlet of the pump inlet pipe of the dehydration pipe through dehydration valves at different positions on the heavy oil storage tank; the three-way diverter valve includes a three-way diverter valve inlet, a three-way diverter valve first outlet, and a three-way diverter valve second outlet; the outlet of the dehydration return oil pump is connected to the inlet of the three-way diverter valve through the pump outlet pipe of the dehydration pipe; the first outlet of the three-way diverter valve is connected to a drainage pipe; the second outlet of the three-way diverter valve is connected to the heavy oil storage tank through a return oil pipe; a tank inlet valve is provided on the return oil pipe; and a flow meter, a first moisture content analyzer, and a second moisture content analyzer are sequentially arranged on the pump outlet pipe of the dehydration pipe along the direction from the dehydration return oil pump to the inlet of the three-way diverter valve.

[0006] The present invention discloses a dehydration system for a heavy oil storage tank, the further technical feature of which is that: the heavy oil storage tank is provided with three dehydration valves in sequence from the top to the bottom of the tank, namely the upper dehydration valve, the middle dehydration valve and the lower dehydration valve, and the heavy oil storage tank is connected to the pump inlet pipe of the dehydration pipe through the upper dehydration valve, the middle dehydration valve and the lower dehydration valve respectively.

[0007] The present invention discloses a dehydration system for a heavy oil storage tank, wherein the dehydration valve is connected to the heavy oil storage tank via a connecting flange.

[0008] The present invention discloses a dehydration system for heavy oil storage tanks, the further technical feature of which is that all dehydration valves are valves with actuators.

[0009] The present invention discloses a dehydration system for a heavy oil storage tank, the further technical feature of which is that: the dehydration valve at the top of the tank is set at a height of 80% to 90% of the height of the tank wall, the dehydration valve at the middle of the tank is set at a height of 40% to 60% of the height of the tank wall, and the dehydration valve at the bottom of the tank is set at a height of 10% to 20% of the height of the tank wall.

[0010] The present invention discloses a dehydration system for heavy oil storage tanks, the further technical feature of which is that the level gauge has a local display function.

[0011] The present invention discloses a dehydration system for heavy oil storage tanks, the further technical feature of which is that the dehydration return oil pump is a pump with strong self-priming capability, such as a gear pump, screw pump, roots pump, vane pump, or cam pump.

[0012] The present invention discloses a dehydration system for heavy oil storage tanks, the further technical feature of which is that the first water content analyzer and the second water content analyzer have online detection functions and can control the operation of the three-way diverter valve through a PLC (programmable logic controller).

[0013] This invention relates to a heavy oil storage tank dehydration system, primarily used for dehydrating heavy oil storage tanks with a specific gravity greater than 1.0. Compared with existing technologies, the advantages of this invention's heavy oil storage tank dehydration system are: (1) At least three dehydration valves are sequentially installed from the top to the bottom of the heavy oil storage tank, preferably at the top, middle, and bottom, enabling dehydration at multiple liquid levels; (2) By installing a dehydration return oil pump, the disadvantage of poor oil return in existing gravity-flow dehydration processes is avoided; (3) By installing two water content analyzers (AND gate control and OR gate control), the concentration of the removed oily wastewater meets environmental protection requirements; (4) By installing a three-way diversion valve, dehydration and oil return are synchronized, avoiding misoperation. Furthermore, this invention can also smoothly remove water from heavy oil storage tanks. This heavy oil storage tank dehydration system features a simple process, convenient installation, low investment, good energy-saving effect, and easy operation.

[0014] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but this does not limit the scope of the invention. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a heavy oil storage tank dehydration system according to the present invention.

[0016] The reference numerals in the figure are:

[0017] 1. Heavy oil storage tank; 2-1. Upper dehydration valve of the tank; 2-2. Middle dehydration valve of the tank; 2-3. Lower dehydration valve of the tank; 3. Pump inlet pipe of the dehydration pipe; 4. Dehydration return oil pump; 5. Pump outlet pipe of the dehydration pipe; 6-1. First water content analyzer; 6-2. Second water content analyzer; 7. Three-way diverter valve inlet; 8. First outlet of the three-way diverter valve; 9. Second outlet of the three-way diverter valve; 10. Three-way diverter valve; 11. Drainage pipe; 12. Return oil pipe; 13. Flow meter; 14. Drainage well; 15. Tank inlet valve; 16. Level gauge. Detailed Implementation

[0018] The following is combined with Figure 1 This invention describes a heavy oil storage tank dehydration system and its operation process.

[0019] like Figure 1 As shown, a heavy oil storage tank dehydration system includes a heavy oil storage tank 1, a dehydration return pump 4, and a three-way diverter valve 10. The heavy oil storage tank 1 is equipped with, from top to bottom, an upper dehydration valve 2-1, a middle dehydration valve 2-2, and a lower dehydration valve 2-3. The inlet of the dehydration return pump 4 is connected to the outlet of the pump inlet pipe 3 of the dehydration pipe. The heavy oil storage tank 1 is connected to the inlet of the pump inlet pipe 3 of the dehydration pipe through the upper dehydration valve 2-1, the middle dehydration valve 2-2, and the lower dehydration valve 2-3, respectively. The three-way diverter valve 10 includes a three-way diverter valve inlet 7 and a three-way branch valve 8. The first outlet 8 of the flow valve and the second outlet 9 of the three-way diverter valve are connected. The outlet of the dehydration return oil pump 4 is connected to the inlet 7 of the three-way diverter valve 10 through the pump outlet pipe 5 of the dehydration pipe. The first outlet 8 of the three-way diverter valve is connected to the drainage pipe 11. The second outlet 9 of the three-way diverter valve is connected to the heavy oil storage tank 1 through the return oil pipe 12. The return oil pipe 12 is equipped with a tank inlet valve 15. The pump outlet pipe 5 of the dehydration pipe is equipped with a flow meter 13, a first water content analyzer 6-1 and a second water content analyzer 6-2 in sequence along the direction from the dehydration return oil pump 4 to the inlet 7 of the three-way diverter valve.

[0020] The upper dehydration valve 2-1 is connected to the heavy oil storage tank 1 via a connecting flange. The upper dehydration valve 2-1 is set at a height of 80% to 90% of the tank wall height of the heavy oil storage tank 1. The upper dehydration valve 2-1 is a valve with an actuator.

[0021] The dehydration valve 2-2 in the middle of the tank is connected to the heavy oil storage tank 1 through a connecting flange. The height of the dehydration valve 2-2 in the middle of the tank is 40% to 60% of the height of the tank wall of the heavy oil storage tank 1. The dehydration valve 2-2 in the middle of the tank is a valve with an actuator.

[0022] The lower dehydration valve 2-3 is connected to the heavy oil storage tank 1 via a connecting flange. The lower dehydration valve 2-3 is installed at a height of 10% to 20% of the tank wall height. The lower dehydration valve 2-3 is a valve with an actuator.

[0023] The installation heights of the upper dehydration valve 2-1, the middle dehydration valve 2-2, and the lower dehydration valve 2-3 of this invention are measured from the center height of the connecting flanges. Specifically, the installation height of the upper dehydration valve 2-1 is the center height of the connecting flange between the upper dehydration valve 2-1 and the heavy oil storage tank 1; the installation height of the middle dehydration valve 2-2 is the center height of the connecting flange between the middle dehydration valve 2-2 and the heavy oil storage tank 1; and the installation height of the lower dehydration valve 2-3 is the center height of the connecting flange between the lower dehydration valve 2-3 and the heavy oil storage tank 1.

[0024] The level gauge 16 has a local display function.

[0025] The dehydration return oil pump 4 is a pump with strong self-priming capability, such as a gear pump, screw pump, roots pump, vane pump, or cam pump.

[0026] The first moisture analyzer 6-1 and the second moisture analyzer 6-2 have online detection functions and can control the operation of the three-way diverter valve 10 through a PLC (programmable logic controller).

[0027] When both the first moisture analyzer 6-1 and the second moisture analyzer 6-2 detect (AND gate control) that the liquid passing through is oily wastewater with an oil concentration not exceeding 20 ppm, the second outlet 9 of the three-way diverter valve is closed simultaneously via PLC interlock, while the first outlet 8 of the three-way diverter valve is opened at the same time. The oily wastewater (concentration not exceeding 20 ppm) is discharged into the drainage well 14 through the first outlet 8 of the three-way diverter valve and the drainage pipe 11. When either the first moisture analyzer 6-1 or the second moisture analyzer 6-2 detects (OR gate control) that the liquid passing through is oily wastewater with an oil concentration exceeding 20 ppm... When water is being discharged, the first outlet 8 of the three-way diverter valve is closed simultaneously via PLC interlock, while the second outlet 9 of the three-way diverter valve is opened at the same time. Oily wastewater (concentration higher than 20ppm) is discharged into the heavy oil storage tank 1 through the second outlet 9 of the three-way diverter valve and the return oil pipeline 12. When there is no oily wastewater being discharged into the drainage well 14 through the drainage pipeline 11, the dehydration return oil pump 4 can be manually shut off. Then, the lower dehydration valve 2-3 and the tank inlet valve 15 are closed, completing the dehydration operation when the heavy oil level in the heavy oil storage tank 1 rises to the center height of the lower dehydration valve 2-3 and the flange connecting the heavy oil storage tank 1.

[0028] The operation process of the heavy oil storage tank dehydration system of the present invention is as follows:

[0029] During the oil recovery process of heavy oil storage tank 1, when the heavy oil level in heavy oil storage tank 1 rises to the center height of the flange connecting the lower dehydration valve 2-3 and the heavy oil storage tank 1, dehydration operation is required. At this time, the middle dehydration valve 2-2, the upper dehydration valve 2-1, and the first outlet 8 of the three-way diverter valve are closed. The second outlet 9 and the inlet 7 of the three-way diverter valve, as well as the lower dehydration valve 2-3 and the tank inlet valve 15 are all open. The dehydration return oil pump 4 is started to extract the liquid in heavy oil storage tank 1. The liquid enters the flow meter 13, the first water content analyzer 6-1 and the second water content analyzer 6-2 in sequence through the lower dehydration valve 2-3, the pump inlet pipe 3 of the dehydration pipe, the dehydration return oil pump 4, and the pump outlet pipe 5 of the dehydration pipe. Then, it enters the three-way diverter valve 10 through the inlet 7 of the three-way diverter valve. If the heavy oil storage tank 1 is being put into operation for the first time: when both the first water content analyzer 6-1 and the second water content analyzer 6-2 detect (AND gate control) that the liquid passing through is oily wastewater with an oil concentration not exceeding 20 ppm, the second outlet 9 of the three-way diverter valve is interlocked and closed, while the first outlet 8 of the three-way diverter valve is opened simultaneously. The oily wastewater (concentration not exceeding 20 ppm) is discharged into the drainage well 14 through the first outlet 8 of the three-way diverter valve and the drainage pipe 11; when either the first water content analyzer 6-1 or the second water content analyzer 6-2 detects (OR gate control) that the oil concentration passing through is higher than 20 ppm... When the oily wastewater is 0 ppm, the first outlet 8 of the three-way diverter valve is closed by interlock, while the second outlet 9 of the three-way diverter valve is opened simultaneously. The oily wastewater (concentration higher than 20 ppm) is discharged into the heavy oil storage tank 1 through the second outlet 9 of the three-way diverter valve and the return oil pipe 12. When there is no oily wastewater discharged into the drainage well 14 through the drainage pipe 11, the dehydration return oil pump 4 can be manually closed. Then, the lower dehydration valve 2-3 and the tank inlet valve 15 are closed, completing the dehydration operation when the heavy oil level in the heavy oil storage tank 1 rises to the center height of the lower dehydration valve 2-3 and the flange connecting the heavy oil storage tank 1.If the heavy oil storage tank 1 is not being used for the first time, during the initial startup of the dehydration return pump 4, oily wastewater with a concentration higher than 20 ppm from the previous dehydration process will remain in the pump inlet pipe 3 and pump outlet pipe 5 of the dehydration pipe. At this time, the first water content analyzer 6-1 and the second water content analyzer 6-2 will detect the oily wastewater with an oil concentration higher than 20 ppm in the pump outlet pipe of the dehydration pipe, and the first outlet 8 of the three-way diverter valve will remain closed. After the dehydration return pump 4 has been running for 30 to 60 seconds, the oily wastewater with an oil concentration higher than 20 ppm in this pipeline will be replaced by oily wastewater with an oil concentration lower than 20 ppm. If the first water content analyzer 6-1... When both the -1 and second water content analyzers 6-2 detect that the liquid passing through is oily wastewater with an oil concentration not exceeding 20 ppm, the second outlet 9 of the three-way diverter valve is closed simultaneously, while the first outlet 8 of the three-way diverter valve is opened at the same time. The oily wastewater (concentration not exceeding 20 ppm) is discharged into the drainage well 14 through the first outlet 8 of the three-way diverter valve and the drainage pipe 11. When no oily wastewater is discharged into the drainage well 14 through the drainage pipe 11, the dehydration return oil pump 4 can be manually closed, and then the lower dehydration valve 2-3 and the tank inlet valve 15 are closed. This completes the dehydration operation when the heavy oil level in the heavy oil storage tank 1 rises to the center height of the lower dehydration valve 2-3 and the flange connecting the heavy oil storage tank 1.

[0030] The dehydration operation process when the heavy oil level in heavy oil storage tank 1 rises to the center height of the dehydration valve 2-2 in the middle of the tank and the connecting flange of heavy oil storage tank 1, and the dehydration operation process when the heavy oil level in heavy oil storage tank 1 rises to the center height of the dehydration valve 2-1 in the upper part of the tank and the connecting flange of heavy oil storage tank 1, are based on the same principle as the dehydration operation process when the heavy oil level in heavy oil storage tank 1 rises to the center height of the dehydration valve 2-3 in the lower part of the tank and the connecting flange of heavy oil storage tank 1, and will not be described again.

[0031] Using the above-mentioned heavy oil storage tank dehydration system, water can be successfully removed from the heavy oil storage tank. This heavy oil storage tank dehydration system also has the advantages of simple process, convenient installation, low investment, good energy-saving effect, and convenient operation.

Claims

1. A heavy oil storage tank dewatering system comprising a heavy oil storage tank, characterized by: The heavy oil tank dehydration system further comprises a dehydration return oil pump and a three-way shunt valve, at least three dehydration valves are sequentially arranged on the heavy oil tank from the upper part to the lower part, the dehydration return oil pump inlet is connected with the outlet of the pump inlet pipeline of the dehydration pipe, the heavy oil tank is communicated with the pump inlet pipeline inlet of the dehydration pipe through the dehydration valves at different positions of the heavy oil tank, the three-way shunt valve comprises a three-way shunt valve inlet, a three-way shunt valve first outlet and a three-way shunt valve second outlet, the dehydration return oil pump outlet is connected with the three-way shunt valve inlet of the three-way shunt valve through the pump outlet pipeline of the dehydration pipe, the three-way shunt valve first outlet is connected with the drainage pipeline, the three-way shunt valve second outlet is connected with the heavy oil tank through the return oil pipeline, the return oil pipeline is provided with a tank inlet valve, and the pump outlet pipeline of the dehydration pipe is sequentially provided with a flow meter, a first water content analyzer and a second water content analyzer in the direction from the dehydration return oil pump to the three-way shunt valve inlet.

2. The heavy oil storage tank dehydration system of claim 1, wherein: The heavy oil tank is sequentially provided with three dehydration valves from the upper part to the lower part, i.e. an upper part dehydration valve, a middle part dehydration valve and a lower part dehydration valve, and the heavy oil tank is communicated with the pump inlet pipeline inlet of the dehydration pipe through the upper part dehydration valve, the middle part dehydration valve and the lower part dehydration valve.

3. The heavy oil storage tank dehydration system of claim 1, wherein: The dehydration valves are all valves with actuators.

4. The heavy oil storage tank dehydration system of claim 1, wherein: The dehydration valves and the heavy oil tank are connected through connecting flanges.

5. The heavy oil storage tank dehydration system of claim 2, wherein: The setting height of the upper part dehydration valve is 80% to 90% of the tank wall height of the heavy oil tank, the setting height of the middle part dehydration valve is 40% to 60% of the tank wall height of the heavy oil tank, and the setting height of the lower part dehydration valve is 10% to 20% of the tank wall height.

6. The heavy oil storage tank dehydration system of claim 1 or 2, wherein: The liquid level meter has an on-site display function.

7. The heavy oil storage tank dehydration system of claim 1 or 2, wherein: The dehydration return oil pump is a pump with strong self-priming capacity.

8. A heavy oil storage tank dehydration system according to claim 7, characterized in that: The dehydration return oil pump is a gear pump, a screw pump, a Roots pump, a sliding vane pump or a cam pump.

9. The heavy oil storage tank dehydration system of claim 1 or 2, wherein: The first water content analyzer and the second water content analyzer have an online detection function and can control the operation of the three-way shunt valve through a programmable logic controller.

10. The heavy oil storage tank dehydration system of claim 1 or 2, wherein: The heavy oil in the heavy oil tank refers to heavy oil with a specific gravity greater than 1.0.

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