Crude oil desalter tank

Abstract

This invention provides a crude oil desalting tank, comprising a tank body and a desalting assembly. The desalting assembly includes a strong electric field coalescing zone providing a strong electric field for an oil-water mixture, a feed distribution component for injecting the oil-water mixture into the strong electric field coalescing zone, and an oil collection component for collecting dehydrated crude oil. The strong electric field coalescing zone is located within the tank body. The feed distribution component includes an upper injection pipe and a lower injection pipe located on the upper and lower sides of the strong electric field coalescing zone, respectively. Each upper and lower injection pipe includes an injection head, and each injection head has at least two spiral injection holes with different injection angles and / or injection depths. The oil collection component is located above the strong electric field coalescing zone. This invention has advantages such as reducing the water and salt content of crude oil, and improving the desalting and dehydration effect and efficiency of crude oil.

Description

Technical Field

[0001] This invention relates to the field of crude oil pretreatment, desalting, and dehydration equipment, and more particularly to a crude oil desalting tank. Background Technology

[0002] Crude oil desalting is an indispensable part of crude oil pretreatment processes and is widely used in oil fields and refineries. The crude oil desalting process involves pre-injecting water into the crude oil, using a static mixer and mixing valves to mix the crude oil and water, allowing as much salt as possible to be washed into the water. The mixed oil-water mixture enters the desalting tank, where, under the influence of an electric field, water droplets in the crude oil generate polarized charges and coalesce to form larger droplets. Due to the density difference between crude oil and water, oil and water separate under the influence of gravity, resulting in desalted and dehydrated crude oil. However, with the increasing difficulty of crude oil extraction and the continuous decline in crude oil quality, the static mixers and mixing valves in existing crude oil desalting tanks are unable to fully mix the oil-water mixture, and the electric field distribution in existing desalting tanks is unreasonable, resulting in poor desalting and dehydration effects and low efficiency. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a crude oil desalting tank that reduces the water content and salt content of crude oil and improves the desalting and dehydration effect and efficiency of crude oil.

[0004] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows:

[0005] A crude oil desalting tank includes a tank body and a desalting assembly. The desalting assembly includes a strong electric field coalescing zone that provides a strong electric field to an oil-water mixture, a feed distribution component that injects the oil-water mixture into the strong electric field coalescing zone, and an oil collection component that collects dehydrated crude oil. The strong electric field coalescing zone is located within the tank body. The feed distribution component includes an upper injection pipe and a lower injection pipe located on the upper and lower sides of the strong electric field coalescing zone, respectively. Each upper injection pipe and the lower injection pipe includes an injection head, and each injection head has at least two spiral injection holes with different injection angles and / or injection depths. The oil collection component is located above the strong electric field coalescing zone.

[0006] As a further improvement to the above technical solution:

[0007] The upper injection pipe and the lower injection pipe are arranged along the length of the strong electric field coalescing region. The bottom end of the upper injection pipe and the top end of the lower injection pipe are each provided with multiple sets of nozzle units arranged along the pipe axis. Each set of nozzle units includes two injection heads arranged at an angle.

[0008] Each of the aforementioned nozzles includes a helical unit, and each helical unit includes an upper helical injection hole and a lower helical injection hole with different starting phase angles and / or leads, wherein the helical generatrix equation of the upper helical injection hole is: The helical generatrix equation of the lower layer helical injection hole is:

[0009] Where R is the inner radius of the nozzle; α is the initial phase angle; β and α are the leads.

[0010] Each group of desalination components has two strong electric field coalescence zones, which are arranged along the width of the tank and symmetrically on both sides of the central axis of the tank.

[0011] The upper and lower spray pipes are horizontally arranged H-shaped spray pipes, wherein each pair of sides of the H-shaped spray pipe corresponds to a set of strong electric field coalescing regions, and the two pairs of sides of the H-shaped spray pipe are arranged along the length direction of the strong electric field coalescing regions.

[0012] The oil collection component includes a horizontally arranged H-shaped oil collection pipe and a vertically arranged oil discharge pipe. The two opposite sides of the H-shaped oil collection pipe correspond to a set of strong electric field coalescing regions, and the two opposite sides of the H-shaped oil collection pipe are arranged along the length direction of the strong electric field coalescing regions. The oil discharge pipe is located in the middle of the H-shaped oil collection pipe.

[0013] The feeding and distributing component also includes a vertical feeding pipe that communicates with the upper injection pipe and the lower injection pipe, the feeding end of the vertical feeding pipe being located outside the tank body; a reinforcing mixing component is provided on the vertical feeding pipe located below the lower injection pipe, the reinforcing mixing component being a reinforcing mixing plate with mixing holes.

[0014] A buffer zone is provided at the connection position between the vertical feed pipe and the upper injection pipe and the lower injection pipe, and the diameter of the buffer zone is larger than the diameter of the vertical feed pipe.

[0015] The tank body is provided with ultrasonic components at both ends along the axis to further promote the aggregation of oil and water droplets. The ultrasonic components and the strong electric field aggregation area are located on the same horizontal plane.

[0016] The strong electric field coalescing region is formed by a positive electrode section and a negative electrode section, which are arranged opposite to each other along the width direction of the tank body; both the positive electrode section and the negative electrode section include a plurality of vertical electrode plates arranged at intervals along the length direction of the tank body.

[0017] Compared with the prior art, the advantages of the present invention are as follows:

[0018] This invention features upper and lower injection pipes on the upper and lower sides of a strong electric field coalescence zone, respectively. This allows the oil-water mixture to be more fully injected into the coalescence zone. Under the influence of the high-intensity electric field and the jet flow from the injection pipes, the oil-water mixture is thoroughly mixed. Simultaneously, each upper and lower injection pipe includes an injection head, and each injection head has at least two spiral injection holes with different injection angles and / or depths. This causes the oil-water mixture ejected from each injection head to collide with each other, resulting in high impact intensity and complex mixing, further enhancing the mixing effect. In short, this invention, by setting injection pipes on the upper and lower sides of the strong electric field coalescence zone and equipping each injection head with spiral injection holes of different injection angles and / or depths, ensures thorough mixing of the oil-water mixture. This promotes the coalescence of oil and water droplets, further reducing the water and salt content of crude oil, and significantly improving the desalting and dehydration effect and efficiency of crude oil. Furthermore, this invention has a compact layout and high space utilization. Attached Figure Description

[0019] The invention will now be described in more detail with reference to embodiments and the accompanying drawings.

[0020] Figure 1 This is a front view of the crude oil desalting tank of the present invention.

[0021] Figure 2 This is a left view of the crude oil desalting tank of the present invention.

[0022] Figure 3 This is a three-dimensional structural diagram of the spray head of the present invention.

[0023] Figure 4 This is a cross-sectional view of the nozzle of the present invention.

[0024] Figure 5 This is a schematic diagram showing the positional relationship of the reinforced hybrid component of the present invention.

[0025] Figure 6 This is a schematic diagram showing the positional relationship of another reinforced hybrid component of the present invention.

[0026] The labels in the diagram represent:

[0027] 1. Tank body; 2. Desalination assembly; 21. Strong electric field coalescing zone; 211. Positive electrode section; 212. Negative electrode section; 213. Vertical electrode plate; 22. Feed distribution component; 221. Upper spray pipe; 222. Lower spray pipe; 223. Spray head; 2231. Spiral spray hole; 2232. Spiral unit; 2233. Upper spiral spray hole; 2234. Lower spiral spray hole; 224. H-shaped spray pipe; 225. Vertical feed pipe; 23. Oil collection component; 231. H-shaped oil collection pipe; 232. Oil discharge pipe; 3. Enhanced mixing component; 31. Mixing hole; 32. Flange; 4. Ultrasonic component; 5. Drain pipe. Detailed Implementation

[0028] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments, but this does not limit the scope of protection of the present invention.

[0029] like Figures 1 to 4 As shown, the crude oil desalting tank in this embodiment includes a tank body 1 and a desalting assembly 2. In this embodiment, the desalination component 2 includes a strong electric field coalescing zone 21, a feed distribution component 22, and an oil collection component 23. The strong electric field coalescing zone 21 is located inside the tank 1 and provides a strong electric field for the oil-water mixture. Water droplets in the crude oil undergo repeated processes of breaking and coalescing in the strong electric field coalescing zone 21, which enhances the mixing of the oil-water mixture. Water droplets in the crude oil will coalesce below and outside the strong electric field coalescing zone 21. The feed distribution component 22 includes an upper injection pipe 221 and a lower injection pipe 222, which are respectively located on the upper and lower sides of the strong electric field coalescing zone 21 to spray the oil-water mixture into the strong electric field coalescing zone 21. Each upper injection pipe 221 and lower injection pipe 222 includes an injection head 223, and each injection head 223 is provided with at least two spiral injection holes with different injection angles and / or injection depths. The oil collection component 23 is located above the strong electric field coalescing zone 21 and is used to collect the dehydrated crude oil. This invention features a compact layout and high space utilization.

[0030] The present invention provides an upper injection pipe 221 and a lower injection pipe 222 on the upper and lower sides of the strong electric field coalescence zone 21, respectively, so that the oil-water mixture can be more fully injected into the strong electric field coalescence zone 21. At this time, the oil-water mixture is fully mixed under the action of the high electric field of the strong electric field coalescence zone 21 and the jet action of the injection pipe. Each upper injection pipe 221 and lower injection pipe 222 includes an injection head 223, and each injection head 223 is provided with at least two spiral injection holes with different injection angles and / or injection depths. This causes the oil-water mixture injected from each injection head 223 to collide with each other, resulting in high impact intensity and high mixing complexity, further improving the mixing effect of the oil-water mixture. The present invention achieves thorough mixing of oil and water mixture by setting spray pipes on the upper and lower sides of the strong electric field coalescence zone 21 and setting spiral spray holes with different spray angles and / or spray depths on each spray head 223. This promotes the coalescence of oil and water droplets, further reduces the water content and salt content of crude oil, and greatly improves the desalting and dehydration effect and efficiency of crude oil.

[0031] like Figure 1As shown, the upper injection pipe 221 and the lower injection pipe 222 are arranged along the length of the strong electric field coalescing zone 21 to ensure that the oil-water mixture is sprayed throughout the entire strong electric field coalescing zone 21, thereby achieving enhanced mixing of the oil-water mixture. Simultaneously, multiple sets of nozzle units are provided at the bottom of the upper injection pipe 221 and the top of the lower injection pipe 222. These multiple sets of nozzle units are arranged along the axial direction of the pipe body, and each set of nozzle units includes two injection heads 223 arranged at an angle to improve the spraying and mixing effect of the oil-water mixture. In this embodiment, the angle between the two injection heads 223 is 60°. In other embodiments, the angle between the two injection heads 223 can be adjusted according to actual conditions.

[0032] like Figure 3 and Figure 4 As shown, each spray head 223 includes two spiral units 2232, which are arranged at intervals along the axial direction of the spray head 223. In this embodiment, each spiral unit 2232 includes an upper spiral spray hole 2233 and a lower spiral spray hole 2234 with different starting phase angles and / or leads. This causes the oil-water mixture to be sprayed out of the spray head 223 in a spiral shape, resulting in a more uniform distribution of the oil-water mixture. Simultaneously, the different starting phase angles and / or leads of the upper spiral spray hole 2233 and the lower spiral spray hole 2234 cause relative movement of the oil-water mixture, effectively increasing the collision probability and promoting the coalescence and growth of droplets, thereby improving the oil-water separation effect. In other embodiments, the number of spiral units 2232 can be adjusted according to actual conditions, such as one, three, or four sets.

[0033] Specifically, the helical generatrix equation of the upper helical injection hole 2233 is:

[0034]

[0035] The helical generatrix equation of the lower helical injection hole 2234 is:

[0036]

[0037] Where R is the inner radius of the nozzle 223; α is the initial phase angle; β is the lead. Because the initial phase angles and / or leads of the upper spiral injection hole 2233 and the lower spiral injection hole 2234 are different, the oil-water mixture is more evenly distributed, thus enhancing the mixing effect.

[0038] like Figure 2 As shown, each desalination component 2 has two sets of strong electric field coalescing zones 21. These two sets of strong electric field coalescing zones 21 are arranged along the width of the tank 1, and are symmetrically arranged on both sides of the central axis of the tank 1, so as to fully utilize the space of the tank 1 to achieve enhanced mixing of the oil-water mixture. Figure 1As shown, in this embodiment, there are two sets of desalination components 2, which are arranged along the length of the tank 1; in other embodiments, the desalination components 2 may also be set to three or four sets, etc.

[0039] Furthermore, the upper injection pipe 221 and the lower injection pipe 222 are horizontally arranged H-shaped injection pipes 224. The two opposite sides of the H-shaped injection pipe 224 correspond to a set of strong electric field coalescence zones 21, and the two opposite sides of the H-shaped injection pipe 224 are arranged along the length direction of the strong electric field coalescence zone 21. This arrangement of one injection pipe ensures that both sets of strong electric field coalescence zones 21 arranged along the width direction of the tank body 1 can effectively receive the oil-water mixture, and the layout is compact and easy to operate.

[0040] like Figure 1 and Figure 2 As shown, the feed distribution component 22 also includes a vertical feed pipe 225, which is connected to the upper injection pipe 221 and the lower injection pipe 222. The feed end of the vertical feed pipe 225 is located outside the tank body 1 to effectively transport the oil-water mixture to the upper injection pipe 221 and the lower injection pipe 222. Meanwhile, a strengthening mixing element 3 is provided on the vertical feed pipe 225 located below the lower injection pipe 222. The strengthening mixing element 3 is a strengthening mixing plate with mixing holes 31. Crude oil is pre-injected with water into the vertical feed pipe 225, where it undergoes thorough collision and mixing through the mixing holes 31 of the strengthening mixing plate, so as to distribute the oil-water mixture as evenly as possible to the strong electric field coalescence zone 21.

[0041] like Figure 5 and Figure 6 As shown, the reinforcing mixer 3 is fixed to the vertical feed pipe 225 via a flange 32. Two reinforcing mixers 3 are provided on each vertical feed pipe 225. The mixing holes 31 of the two reinforcing mixers 3 are respectively configured as inverted conical holes and multiple through holes arranged in an array, which effectively increases the reinforcing mixing effect of the oil-water mixture. In other embodiments, the number of reinforcing mixers 3 and the arrangement of the mixing holes 31 on each vertical feed pipe 225 can be adjusted according to actual conditions, such as providing one or three reinforcing mixers 3 on each vertical feed pipe 225, and the mixing holes 31 can be configured as conical holes or polygonal holes, etc.

[0042] Furthermore, a buffer zone is provided at the connection point between the vertical feed pipe 225 and the upper injection pipe 221 and the lower injection pipe 222. The diameter of the buffer zone is larger than the diameter of the vertical feed pipe 225. This buffer zone acts as a buffer when the oil-water mixture enters the upper injection pipe 221 and the lower injection pipe 222, preventing the oil-water mixture from being sprayed out of the injection head 223 at an excessively high speed. This effectively balances the flow load of each injection head 223 and ensures uniform spraying of the oil-water mixture.

[0043] In this embodiment, the oil collection component 23 includes an H-shaped oil collection pipe 231 and an oil discharge pipe 232. The H-shaped oil collection pipe 231 is horizontally positioned, with each pair of opposite sides corresponding to a set of strong electric field coalescing zones 21, and these opposite sides are arranged along the length of the strong electric field coalescing zones 21. The oil discharge pipe 232 is vertically positioned in the middle of the H-shaped oil collection pipe 231, with one end extending from the top of the tank body 1 to the outside of the tank body 1. The H-shaped oil collection pipe 231 ensures that the dehydrated crude oil from both sets of strong electric field coalescing zones 21, arranged along the width of the tank body 1, can be effectively collected, and the layout is simple and compact.

[0044] Furthermore, the top of each of the two opposite sides of the H-shaped oil receiving pipe 231 is provided with oil receiving holes, which are arranged along the length of the two opposite sides of the H-shaped oil receiving pipe 231. The dehydrated crude oil after oil-water separation enters the H-shaped oil receiving pipe 231 through the oil receiving holes and is discharged from the top of the tank 1 through the oil discharge pipe 232. The opening at the top of the H-shaped oil receiving pipe 231 effectively increases the residence time of the crude oil in the tank, allowing full utilization of the space in the tank 1 to achieve crude oil dehydration and desalination.

[0045] like Figure 1 As shown, ultrasonic components 4 are provided at both ends of the tank body 1 along its axis. The ultrasonic components 4 and the strong electric field coalescing zone 21 are located on the same horizontal plane. The ultrasonic action further increases the relative motion between the oil and water mixture, further promoting the aggregation of the oil and water mixture and making the dehydration more complete.

[0046] In this embodiment, the strong electric field coalescence region 21 is formed by a positive electrode portion 211 and a negative electrode portion 212, which are arranged opposite to each other along the width direction of the tank body 1. Both the positive electrode portion 211 and the negative electrode portion 212 include a plurality of vertical electrode plates 213, which are arranged at intervals along the length direction of the tank body 1 to provide a high-intensity electric field.

[0047] The change in the distance between the positive electrode portion 211 and the negative electrode portion 212 will affect the current intensity and fluid flow in the strong electric field coalescing region 21. Since the magnitude of the electric field intensity in the strong electric field coalescing region 21 is negatively correlated with the distance between the positive electrode portion 211 and the negative electrode portion 212, reducing the distance between the positive electrode portion 211 and the negative electrode portion 212 can effectively increase the electric field intensity in the strong electric field coalescing region 21. For example, when a 25KV sinusoidal alternating current is applied, the electric field intensity in the strong electric field coalescing region 21 is only 1164V / cm when the distance between the positive electrode portion 211 and the negative electrode portion 212 is 200mm; while when the distance between the positive electrode portion 211 and the negative electrode portion 212 is reduced to 150mm, the electric field intensity in the strong electric field coalescing region 21 can be increased to 1575V / cm. Meanwhile, the reduction in the distance between the positive electrode portion 211 and the negative electrode portion 212 will inevitably affect the flow of fluid inside the electrostatic desalination tank; that is, the reduction in the distance between the positive electrode portion 211 and the negative electrode portion 212 will increase the fluid flow resistance. Therefore, while reducing the distance between the positive electrode portion 211 and the negative electrode portion 212 to enhance the electric field strength of the electric field coalescing region 21, the present invention reduces the fluid flow resistance caused by reducing the distance between the positive electrode portion 211 and the negative electrode portion 212 by reducing the cross-sectional area of ​​the vertical electrode plate 213, thereby optimizing the fluid flow inside the tank.

[0048] In this embodiment, a drain pipe 5 is provided in the bottom middle area of ​​the tank 1 so that the wastewater after oil-water separation can be discharged through the drain pipe 5 for subsequent treatment.

[0049] The operation method of the crude oil desalting tank of the present invention is as follows: crude oil is pre-injected with water, mixed by a static mixer and a mixing valve, and then enters the tank 1 through a vertical feed pipe 225. Due to the action of the enhanced mixing plate, the oil-water mixture undergoes a first enhanced mixing. In the H-shaped injection pipe 224, due to the jet action of the injection head 223, the oil-water mixture undergoes a second enhanced mixing. Due to the mutual collision of the oil-water mixture sprayed by the upper injection pipe 221 and the lower injection pipe 222, the oil-water mixture undergoes a third enhanced mixing. In the strong electric field coalescence zone 21, due to the action of the high-intensity electric field, crude oil droplets repeatedly collide and coalesce, and the oil-water mixture undergoes a fourth enhanced mixing. The present invention, through four enhanced mixing processes, makes the oil-water mixture more uniformly mixed. At the same time, the ultrasonic component 4 promotes the relative movement of the oil-water mixture and causes coalescence, which can effectively improve the mixing effect of the oil-water mixture and improve the desalting and dehydration effect of crude oil.

[0050] Due to inertia, water droplets move downwards with the crude oil, leaving the strong electric field coalescing zone 21. They coalesce in the weak electric field below zone 21. Because of the density difference between crude oil and water, the coalesced droplets separate from the crude oil under the influence of gravity. The water continues to move downwards and is eventually discharged through the drain pipe 5 at the bottom of tank 1. The crude oil moves upwards, and the water droplets remaining in zone 21 further coalesce and separate from the crude oil, reducing its water content. Finally, the desalted and dehydrated crude oil is collected from the oil receiving component 23 and discharged from the top of the tank.

[0051] Although the invention has been described with reference to preferred embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, the technical features mentioned in the various embodiments can be combined in any manner as long as there is no structural conflict. The invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A crude oil desalting tank, comprising a tank body (1) and a desalting assembly (2), characterized in that, The desalination assembly includes: Provides a strong electric field coalescence region for oil-water mixtures (21). The feed distribution unit (22) that injects the oil-water mixture into the strong electric field coalescence zone, and Oil collection component for collecting dehydrated crude oil (23); The strong electric field coalescing zone is located inside the tank. The feeding distribution component includes an upper injection pipe (221) and a lower injection pipe (222) disposed on the upper and lower sides of the strong electric field coalescence zone for spraying oil-water mixture. Each upper injection pipe and the lower injection pipe includes an injection head (223). Each injection head is provided with at least two spiral injection holes (2232) with different injection angles and / or injection depths. The feeding distribution component also includes a vertical feeding pipe (225). The lower end of the vertical feeding pipe forms a feeding end and is located outside the tank. The vertical feeding pipe extends vertically upward into the tank. The vertical feeding pipe is connected to the lower injection pipe and the upper injection pipe in sequence from bottom to top. An enhanced mixing component is provided on the vertical feeding pipe located below the lower injection pipe. The enhanced mixing component is an enhanced mixing plate with mixing holes, which is used to increase the enhanced mixing effect of the oil-water mixture. Each group of desalination components has two strong electric field coalescing zones. The two groups of strong electric field coalescing zones are arranged along the width of the tank and symmetrically on both sides of the central axis of the tank. The upper spray pipe and the lower spray pipe are horizontally arranged H-shaped spray pipes. Each pair of sides of the H-shaped spray pipe corresponds to one group of strong electric field coalescing zones, and the two pairs of sides of the H-shaped spray pipe are arranged along the length of the strong electric field coalescing zone. The oil collection component is located above the strong electric field coalescing zone. The upper injection pipe and the lower injection pipe are arranged along the length of the strong electric field coalescing zone. The bottom end of the upper injection pipe and the top end of the lower injection pipe are each provided with multiple sets of nozzle units arranged along the pipe axis. Each set of nozzle units includes two injection heads arranged at an angle. Each of the aforementioned nozzles includes two spiral units, which are arranged at intervals along the axial direction of the nozzle. Each spiral unit includes an upper spiral nozzle and a lower spiral nozzle with different starting phase angles and / or leads.

2. The crude oil desalting tank according to claim 1, characterized in that, The helical generatrix equation of the upper helical injection hole is: The helical generatrix equation of the lower layer helical injection hole is: Where R is the inner radius of the nozzle; The initial phase angle; For the guide.

3. The crude oil desalting tank according to claim 1 or 2, characterized in that, The oil collection component includes a horizontally arranged H-shaped oil collection pipe and a vertically arranged oil discharge pipe. The two opposite sides of the H-shaped oil collection pipe correspond to a set of strong electric field coalescing regions, and the two opposite sides of the H-shaped oil collection pipe are arranged along the length direction of the strong electric field coalescing regions. The oil discharge pipe is located in the middle of the H-shaped oil collection pipe.

4. The crude oil desalting tank according to claim 1 or 2, characterized in that, A buffer zone is provided at the connection position between the vertical feed pipe and the upper injection pipe and the lower injection pipe, and the diameter of the buffer zone is larger than the diameter of the vertical feed pipe.

5. The crude oil desalting tank according to claim 1 or 2, characterized in that, The tank body is provided with ultrasonic components at both ends along the axis to further promote the aggregation of oil and water droplets. The ultrasonic components and the strong electric field aggregation area are located on the same horizontal plane.

6. The crude oil desalting tank according to claim 1 or 2, characterized in that, The strong electric field coalescing region is formed by a positive electrode section and a negative electrode section, which are arranged opposite to each other along the width direction of the tank body; both the positive electrode section and the negative electrode section include a plurality of vertical electrode plates arranged at intervals along the length direction of the tank body.

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