System for enhancing desalting and dewatering effects of crude oil and use method thereof

Abstract

The invention relates to a system for strengthening crude oil desalting and dewatering effects and a using method thereof in the technical field of crude oil desalting and dewatering. The system comprises an electric desalting tank, an oil outlet pipe is arranged on the upper tank wall of the electric desalting tank, a feeding main pipe and a drainage pipe are arranged on the lower tank wall of the electric desalting tank, and an electric field area is arranged in the center in the electric desalting tank; a feeding distributor is correspondingly arranged below the electric field area, the feeding distributor comprises a plurality of distribution heads, a stuffing box for vertically dividing an inner cavity into a distribution cavity and a feeding cavity is arranged in the center of each distribution head, and a plurality of corrugated plates which are arranged side by side at intervals are arranged in each stuffing box; the upper end and the lower end of a clamping cavity between two adjacent corrugated plates are correspondingly communicated with the distribution cavity and the feeding cavity respectively, the feeding cavity is correspondingly communicated with the feeding main pipe, and a plurality of distribution holes are formed in the outer cavity wall of the distribution cavity; a flow guide fence for guiding oil and water to pass through the electric field area is arranged around the electric field area; according to the system and the using method thereof, the diameter of water drops can be increased through the feeding distributor, more oil and water can be uniformly led to an electric field region, and the desalting and dewatering effects are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of crude oil desalting and dehydrating, and in particular to a system for enhancing the desalting and dehydrating effect of crude oil and a method for using the system. Background Art

[0002] Crude oil electric desalting technology is the first step in the crude oil processing process. Its desalting and dehydration effect directly affects the target product yield, equipment operation cycle and production process safety of crude oil post-processing process. The essence of crude oil electric desalting is dehydration. Generally, a certain proportion of washing water is fully mixed with the crude oil before desalting, and the water-soluble inorganic salts and hydrophilic mud and other solid impurities contained in the crude oil are extracted into the washing water by the principle of like dissolves like. Then the oil-water mixture is introduced into the electric desalting tank. Under the combined action of demulsifier, temperature, electric field force and gravity, the oil-water emulsion is quickly demulsified and separated. The water phase is discharged from the bottom of the electric desalting tank due to its high density, and the crude oil after desalting is discharged from the top of the desalting tank due to its low density. The dehydration effect of crude oil electric desalting is affected by many factors such as crude oil properties, water injection volume, water injection quality, mixing intensity, electric field strength, and the way the oil-water mixture enters the tank. The most critical factors are crude oil properties, electric field form and strength. In order to improve the desalting and dehydration efficiency of crude oil electric desalting devices, electric desalting technologies such as AC desalting technology, DC desalting technology, AC-DC desalting technology, and multi-electric field combination electric desalting technology have been developed. However, with the continuous heaviness and inferiority of crude oil, the density difference between oil and water becomes smaller, and the stability of the emulsion is enhanced. In order to improve the desalting and dehydration effect, it is necessary to continuously increase the oil-water mixing intensity, which leads to a further reduction in the dispersion diameter of water droplets in crude oil and a further increase in the difficulty of demulsification. The electric field strength required to achieve a good oil-water separation effect continues to increase. The development of electric desalting technology with the goal of continuously improving the electric field form and increasing the electric field strength has also encountered bottlenecks. Although previous crude oil electric desalting equipment has made a lot of efforts to enhance the desalting and dehydration effects, there are generally two problems: first, the diameter of water droplets entering the electric field area becomes smaller, and the energy required to achieve the coalescence and growth of tiny water droplets increases, the operating voltage and load of the electric desalting transformer increase, and higher requirements are placed on internal components such as electrode introduction and insulation suspension; second, in order to prevent the electric desalting transformer from tripping due to discharge between the electrode plate and the inner wall of the tank, the existing electric desalting tank will set the distance between the electrode plate and the inner wall of the electric desalting tank to be larger and larger as the electric field strength increases. This results in about 15% of the oil-water mixture not being forced to break and dehydrate through the electric field area, but directly flowing out of the electric desalting tank from the gap between the electric field area and the inner wall of the electric desalting tank, and the space between the electric field area and the two end heads of the electric desalting tank, resulting in an increase in the salt and water content of the crude oil after desalting, and a poor desalting and dehydration effect. Summary of the invention

[0003] In order to overcome the deficiencies in the background technology and solve the existing technical problems, the present invention discloses a system for enhancing the desalting and dehydrating effects of crude oil and a method of using the system, which can increase the diameter of water droplets through a feed distributor and evenly guide more oil and water to the electric field area, thereby improving the desalting and dehydrating effects.

[0004] To achieve the above object, the present invention adopts the following technical solution: A system for enhancing the desalting and dehydrating effect of crude oil comprises a horizontal electric desalter, wherein the upper tank wall of the electric desalter is provided with an oil outlet pipe, the lower tank wall of the electric desalter is provided with a feed main pipe and a drain pipe, and an electric field zone is provided in the center of the electric desalter; a feed distributor is provided correspondingly below the electric field zone, the feed distributor comprises a plurality of spaced-apart and side-by-side distribution heads having an inner cavity, a stuffing box is provided in the center of the distribution head for dividing the inner cavity into a distribution cavity and a feed cavity from top to bottom, a plurality of spaced-apart and side-by-side corrugated plates are provided in the stuffing box, the upper end and the lower end of the cavity between two adjacent corrugated plates are respectively connected with the distribution cavity and the feed cavity, the feed cavity is connected with the feed main pipe through a feed branch pipe, and a plurality of distribution holes are provided in the outer cavity wall of the distribution cavity; a flow guide enclosure made of high-temperature resistant electrical insulating material is provided around the electric field zone to guide the oil and water materials entering from the feed main pipe to pass through the electric field zone.

[0005] Furthermore, the electric field zone is a rectangular electric field formed by flat plate electrodes, and the electric field zone is divided into a strong electric field layer and a weak electric field layer from top to bottom; the guide enclosure includes two radial baffles and two axial baffles corresponding to the electric field zone, both end plate edges of the radial baffles extend along the plate surface and are sealed and fixed to the corresponding inner wall of the electric desalination tank, the upper side plate edge of the radial baffle is folded outward and extended to be sealed and fixed to the corresponding head of the electric desalination tank, and the two ends of the axial baffle are respectively close to the two radial baffles, and the upper side plate edge of the axial baffle is folded outward and extended to be sealed and fixed to the corresponding tank wall of the electric desalination tank.

[0006] Furthermore, a plurality of distribution pipes arranged at intervals along the axial direction of the electric desalination tank are fixed to the plate surface of the axial baffle corresponding to the weak electric field layer, one end of the distribution pipe is open and passes through the corresponding axial baffle, the other end of the distribution pipe is closed and extends close to the center of the electric field area, and the pipe wall of the distribution pipe is provided with a plurality of dispersion holes at intervals along the axial direction of the pipe body.

[0007] Furthermore, a gap of less than or equal to 50 mm is left between the plate surfaces of the radial baffles and the axial baffles and the electric field area; and support rods are provided between the plate surfaces of the radial baffles and the axial baffles away from the electric field area and the tank wall of the electric desalination tank.

[0008] Furthermore, a hydrophilic layer is provided on the surface of the corrugated plate, the spacing between two adjacent corrugated plates is 8 to 15 mm, and tear holes are provided at the troughs of the corrugated plates.

[0009] Furthermore, two corrugated plate groups are symmetrically arranged on both sides of the stuffing box, each corrugated plate group includes a plurality of spaced and parallel corrugated plates, the angle between the corrugated plates and the horizontal plane is 50 to 80 degrees, and a feed clamping cavity connected to the feed cavity is provided between the two corrugated plate groups.

[0010] Furthermore, the distribution head is a long strip structure along the length direction of the electric field zone, the cross-section of the feed chamber is an inverted trapezoid, and the feed branch pipe is connected to the center of the bottom wall of the feed chamber; the distribution chamber includes three cavities corresponding to the top surface and two side surfaces of the stuffing box respectively, and each cavity outer wall is provided with multiple rows of distribution hole groups, and each row of distribution hole groups is evenly spaced along the length direction of the distribution head. A plurality of distribution holes are arranged, and the total cross-sectional area of ​​all the distribution holes is 1.1 to 1.5 times the flow cross-sectional area of ​​the feed main pipe.

[0011] Furthermore, the feed distributor is provided in plurality, and the distance between the distribution head of each feed distributor and the electric field zone is greater than or equal to 350 mm.

[0012] Furthermore, the inner end of the oil outlet pipe is connected to an oil collecting pipe parallel to the electric field area, the lower wall of the oil collecting pipe is provided with an oil collecting port, and the lower wall of the electric desalting tank is provided with a manhole.

[0013] A method for using a system for enhancing the desalting and dehydrating effect of crude oil, the method comprising the following steps: feeding an oil-water mixture formed by enhanced mixed crude oil and washing water from a feed main pipe, and then continuously entering a distribution head of a feed distributor through a feed branch pipe, and passing through a stuffing box, and realizing primary demulsification and agglomeration under the action of a regular corrugated plate stuffing, wherein some small water droplets are aggregated into large water droplets, and then uniformly distributed to an electric desalter through distribution holes; large water droplets formed by the initial agglomeration in the feed distributor fall into a water phase located at the lower part of the electric desalter by virtue of a density difference, and can be discharged from a drain pipe, and the remaining oil-water mixture with small water droplets is ... The oil-water mixture is restricted by the radial baffles and the axial baffles, and most of it goes up into the weak electric field layer. A small part of the oil-water mixture goes up along the space surrounded by the radial baffles, the axial baffles and the inner wall of the electric desalter. Due to the closed restriction on the sides of the radial baffles and the axial baffles, it can only enter the middle of the weak electric field layer through the dispersion holes on the distribution pipe. After the two streams of oil-water mixture merge, they continue to go up along the weak electric field layer into the strong electric field layer, and undergo secondary demulsification and agglomeration under the action of the step-shaped electric field force. The crude oil that has undergone secondary desalting and dehydration rises continuously to the top of the electric desalter, and flows out of the electric desalter along the oil collecting pipe and the oil outlet pipe.

[0014] Due to the adoption of the above-mentioned technical solution, the present invention has the following beneficial effects: In the process of crude oil electrical desalting, the dipole cohesion force between tiny water droplets is related to the crude oil dielectric constant, electric field strength, water droplet radius and water droplet center distance. When the washing water injection amount and mixing intensity are constant, the water droplet center distance does not change with the change of external process conditions. Therefore, under certain crude oil properties and electrical desalting conditions, the only way to improve the water droplet cohesion force is to increase the water droplet radius; however, it must be pointed out that this measure of increasing the water droplet radius can only be carried out after the oil and water are mixed, otherwise it will seriously weaken the desalting and dehydration effect of the crude oil electrical desalting device. That is, to achieve good desalting and dehydration, the crude oil and washing water must first be strongly mixed to achieve good extraction, and then the water droplet cohesion effect can be strengthened.

[0015] The system and method for using the system for enhancing the desalting and dehydrating effect of crude oil disclosed in the present invention can achieve the goal of evenly distributing the oil-water mixture at a certain height in the electric desalter and minimize the disturbance to the oil phase and the water phase. At the same time, the system relies on the agglomeration effect of the corrugated plate filler surface on small water droplets and the increased probability of water droplet collision when the oil-water mixture flows through the crests and troughs of the corrugated plate to perform the initial demulsification and agglomeration of water droplets dispersed in the oil-water mixture, thereby achieving the rapid growth of tiny water droplets in the oil-water feed distributor, increasing the diameter of water droplets entering the electric field area of ​​the electric desalter, and reducing the large water droplets formed by the initial agglomeration before entering the electric field area. The water content of the oil-water mixture in the field creates good conditions for establishing a high-intensity electric field. The higher the electric field intensity, the greater the cohesive force generated, the better the demulsification effect, and the more obvious the effect of enhanced desalting and dehydration. More importantly, by setting a diversion enclosure in the electric desalter, the oil-water mixture entering the electric field area can be increased from less than 85% in the existing technology to more than 98%, maximizing the use of the strongest demulsification and agglomeration effect of the electric field force in the electric desalter, achieving effective coupling of the initial demulsification and agglomeration of the hydrophilic filler and the strong secondary demulsification and agglomeration of the electric field force, significantly improving the desalting and dehydration capacity of the electric desalter and its adaptability to heavy and inferior crude oil. In addition, the present invention has a simple structure and low manufacturing cost. It can be used for newly building heavy and inferior crude oil electric desalting devices, and can also guide the technical transformation of existing electric desalting devices. The implementation process is safe and reliable, thereby greatly improving the operating efficiency of existing electric desalting devices and their adaptability to inferior crude oil. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the implementation structure of the present invention; Figure 2 yes Figure 1 AA section structural diagram; Figure 3 yes Figure 2 BB-direction cross-sectional structural diagram; Figure 4 is a schematic diagram of the implementation structure of the feed distributor; Figure 5 yes Figure 4 A schematic diagram of a top view structure; Figure 6 yes Figure 4 A side view schematic diagram of the structure; Figure 7 It is a schematic diagram of the installation and connection structure of the stuffing box.

[0017] In the figure: 1. feed main pipe; 2. feed branch pipe; 3. distribution head; 301. distribution hole; 302. distribution cavity; 303. feed cavity; 4. stuffing box; 401. corrugated plate; 402. tear hole; 403. feed clamp cavity; 5. electric desalting tank; 6. electric field area; 601. strong electric field layer; 602. weak electric field layer; 7. oil outlet pipe; 8. radial baffle; 9. axial baffle; 10. drain pipe; 11. oil collecting pipe; 12. distribution pipe; 13. dispersion hole. DETAILED DESCRIPTION

[0018] The technical solution of the present invention will be described below in conjunction with the drawings in the embodiments of the present invention. In the description, it should be understood that if there are terms such as "upper", "lower", "front", "back", "left", "right", etc. indicating directions or positional relationships, they only correspond to the drawings of the present invention and are for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific direction. Embodiment 1:

[0019] Combined with Figure 1 The system for enhancing the desalting and dehydrating effect of crude oil comprises a horizontal electric desalter 5, an oil outlet pipe 7 is provided on the upper tank wall of the electric desalter 5, a feed main pipe 1 and a drain pipe 10 are provided on the lower tank wall of the electric desalter 5, the inner end of the oil outlet pipe 7 is connected to an oil collecting pipe 11 parallel to the electric field area 6, an oil collecting port is provided on the lower pipe wall of the oil collecting pipe 11, and a manhole is provided on the lower tank wall of the electric desalter 5 for inspection and maintenance; An electric field area 6 is provided in the center of the electric desalting tank 5, and a feed distributor is provided correspondingly below the electric field area 6. Through the feed distributor, the oil and water materials can be evenly and slowly fed into the electric field area 6; according to the size of the electric field area 6, a plurality of feed distributors can be provided, and the spacing between the distribution head 3 of each feed distributor and the electric field area 6 is greater than or equal to 350 mm, so as to avoid electric field interference and prevent premature demulsification and aggregation in the distribution head 3; the feed distributor comprises a plurality of distribution heads 3 spaced side by side and having an inner cavity, and a stuffing box 4 is provided in the center of the distribution head 3, which divides the inner cavity into a distribution cavity 302 and a feed cavity 303 from top to bottom, so that the oil and water entering the feed cavity 303 must pass through the stuffing box 4 before entering the distribution cavity 302, and specifically, a stuffing box 4 can be provided at the lower end of the inner cavity of the distribution head 3. The diaphragm is used to separate the feed cavity 303 below first, and then the stuffing box 4 is fixed to the middle of the upper plate surface of the diaphragm, so that the inner cavity of the distribution head 3 above the diaphragm except the stuffing box 4 forms a distribution cavity 302; a plurality of spaced and parallel corrugated plates 401 are arranged in the stuffing box 4; as needed, the plate surface of the corrugated plate 401 is provided with a hydrophilic layer, which can increase the oil-water aggregation effect, and the spacing between two adjacent corrugated plates 401 is 8 to 15 mm, which can increase the collision effect of oil and water droplets, and the trough of the corrugated plate 401 is provided with a tear hole 402. When the water droplets grow to a certain volume, they can pass through the tear hole 402 to reach the other side of the corrugated plate 401 and realize the wetting of the surface of the other side, which can also play a role in strengthening the adsorption and aggregation of water droplets to a certain extent; the adjacent corrugated plates 401 are sandwiched between The upper and lower ends of the cavity are respectively connected with the distribution cavity 302 and the feed cavity 303 to ensure that the sprayed oil and water must pass through the corrugated plate 401. Specifically, holes are punched at the position corresponding to the lower end of the cavity between two adjacent corrugated plates 401 on the partition plate and the lower box wall of the stuffing box 4, and holes are punched at the position corresponding to the upper end of the cavity between two adjacent corrugated plates 401 on the other box walls of the stuffing box 4. The feed cavity 303 is connected with the feed main pipe 1 through the feed branch pipe 2. The outer cavity wall of the distribution cavity 302 is provided with a plurality of distribution holes 301. According to needs, the distribution head 3 is a long strip structure along the length direction of the electric field area 6. A plurality of distribution heads 3 are arranged side by side to adapt to the shape of the electric field area in the electric desalting tank. The cross section of the feed cavity 303 is an inverted trapezoid, and the angle between the hypotenuse of the inverted trapezoid and the horizontal plane is 30 to 70 degrees, which is preferably The angle is selected to be 45 to 60 degrees, and the feed branch pipe 2 is connected to the center of the bottom wall of the feed chamber 303 to ensure that the oil and water entering the feed chamber 303 can be evenly dispersed; the distribution chamber 302 includes three cavities corresponding to the top surface and two side surfaces of the stuffing box 4, and each cavity outer wall is provided with multiple rows of distribution hole groups, and each row of distribution hole groups is evenly spaced along the length direction of the distribution head 3. A plurality of distribution holes 301 are evenly spaced, so that the oil and water sprayed from the distribution holes 301 can be sprayed in two directions horizontally and vertically upward, and evenly distributed to the cross section of a certain height of the electric desalting tank 5; the total cross-sectional area of ​​all the distribution holes 301 is 1.1 to 1.5 times the flow cross-sectional area of ​​the feed main pipe 1, ensuring that the oil and water sent into the feed main pipe 1 can be smoothly and evenly sprayed from the distribution holes 301 to avoid excessive spraying disturbance; The electric field area 6 is surrounded by a flow-guiding enclosure made of high-temperature resistant electrical insulating material to guide the oil and water materials entering from the feed main pipe 1 to pass through the electric field area 6. The flow-guiding enclosure only has a diameter-reducing effect around the electric field area 6 to limit the flow of oil and water. The flow-guiding enclosure is generally made of nylon 66, polyimide resin, phenolic resin, polytetrafluoroethylene resin and the like, preferably polytetrafluoroethylene resin. According to needs, the electric field area 6 is a rectangular electric field formed by a flat plate electrode, and the electric field area 6 is divided into a strong electric field layer 601 and a The weak electric field layer 602, the strong electric field layer 601 and the weak electric field layer 602 can also be further divided into layers as needed; the diversion enclosure includes two radial baffles 8 and two axial baffles 9 corresponding to the electric field area 6, and the radial baffles 8 and the axial baffles 9 are in a vertical state with respect to the electric field area 6, and the upper sides of the two radial baffles 8 and the two axial baffles 9 are respectively flush with the upper surface of the electric field area 6, and the lower sides can slightly extend out of the lower surface of the electric field area 6; the plate edges at both ends of the radial baffle 8 extend along the plate surface and are connected to the electric desalination The corresponding inner wall of the tank 5 is sealed and fixed, and the upper side plate edge of the radial baffle 8 is folded outward and extended to be sealed and fixed with the corresponding head of the electric desalting tank 5, so that it can be ensured that the oil-water mixture will not flow through the space between the radial baffle 8 and the head of the nearby electric desalting tank 5. The two ends of the axial baffle 9 are respectively close to the two radial baffles 8, and the distance is generally less than or equal to 50mm. The upper side plate edge of the axial baffle 9 is folded outward and extended to be sealed and fixed with the corresponding tank wall of the electric desalting tank 5, which also ensures that the oil-water mixture will not flow through the space between the axial baffle 9 and the nearby The oil and water flow through the space between the tank walls of the corresponding electric desalting tank 5; in addition, a gap of less than or equal to 50 mm is left between the plate surfaces of the radial baffle 8 and the axial baffle 9 and the electric field area 6 to ensure that the gap is small enough to prevent the oil-water mixture from passing through the gap; in order to ensure that the radial baffle 8 and the axial baffle 9 are firmly installed, a support rod can be provided between the plate surfaces of the radial baffle 8 and the axial baffle 9 away from the electric field area 6 and the tank wall of the electric desalting tank 5, and a plurality of support rods can be provided, and the support rods are composed of transverse braces and diagonal braces. Embodiment 2:

[0020] Based on the first embodiment, as shown in the attached Figure 7As shown, two corrugated plate groups are symmetrically arranged on both sides of the stuffing box 4, each corrugated plate group includes a plurality of corrugated plates 401 spaced and arranged side by side, a feed clamping cavity 403 connected to the feed cavity 303 is arranged between the two corrugated plate groups, the feed clamping cavity 403 is formed by two vertical clamping plates, and a flow hole is arranged on the plate surface between the two clamping plates corresponding to the horizontal partition plate, so that the feed clamping cavity 403 connected to the feed cavity 303 can be connected, and the clamping plate can be convenient for firmly fixing the corrugated plate 401, when the corrugated plate 401 and the horizontal clamping plate are When the angle is 50 to 80 degrees, it is generally set to 60 to 75 degrees. The lower end of the cavity between two adjacent corrugated plates 401 corresponds to the plate surface of the splint, and a hole is opened on the corresponding plate surface of the splint to ensure that the lower end of the cavity between the two corrugated plates 401 is connected with the feed cavity 303; this design structure can avoid the formation of a dead zone in the oil-water mixture in the distribution head 3, fully exert the overall agglomeration effect of the corrugated plate 401 filler, and prevent the distribution head 3 from being blocked by a small amount of mud and solid impurities entrained in the crude oil. Embodiment three:

[0021] Although the radial baffles 8 and axial baffles 9 are simply arranged, the installation and setting are simple and will not reduce the volume of the electric desalter 5. However, it is easy to form a flow dead zone between the outer plate surface of the axial baffle 9 and the tank wall of the electric desalter 5. In order to avoid this situation, on the basis of the first embodiment, a plurality of distribution pipes 12 arranged at intervals along the axial direction of the electric desalter 5 can be fixed on the plate surface of the axial baffle 9 corresponding to the weak electric field layer 602. The distribution pipes 12 are also made of high temperature resistant electrical insulating materials. One end of the distribution pipe 12 is open and passes through the corresponding axial baffle 9, and the other end of the distribution pipe 12 is closed and extends close to the center of the electric field area 6. The wall of the distribution pipe 12 is provided with a plurality of dispersion holes 13 at intervals along the axial direction of the pipe body. In this way, a small portion of the oil-water mixture ascends along the space surrounded by the radial baffles 8, the axial baffles 9 and the inner wall of the electric desalter 5. Due to the closed restriction of the upper side of the radial baffles 8 and the axial baffles 9, it can only enter the middle part of the weak electric field layer 602 through the dispersion holes 13 on the distribution pipe 12 to break the emulsion and aggregate.

[0022] The method of using the system of the present invention is as follows: the oil-water mixture formed by the enhanced mixed crude oil and the washing water is fed from the feed main pipe 1, and then continuously enters the distribution head 3 of the feed distributor through the feed branch pipe 2, and passes through the stuffing box 4, and realizes the initial demulsification and agglomeration under the action of the regular corrugated plate 401 filler, wherein some small water droplets are aggregated into large water droplets, and then uniformly distributed to the electric desalter 5 through the distribution hole 301; the large water droplets formed by the initial agglomeration in the feed distributor fall into the water phase located at the lower part of the electric desalter 5 due to the density difference, and can be discharged from the drain pipe 10, and the remaining oil-water mixture with small water droplets is subjected to the radial baffle 8 and the axial baffle 8. 9, most of the oil-water mixture goes up into the weak electric field layer 602, and a small part of the oil-water mixture goes up along the space surrounded by the radial baffle 8, the axial baffle 9 and the inner wall of the electric desalter 5. Due to the closed restriction of the upper side of the radial baffle 8 and the axial baffle 9, it can only enter the middle of the weak electric field layer 602 through the dispersion holes 13 on the distribution pipe 12. After the two streams of oil-water mixture merge, they continue to go up along the weak electric field layer 602 into the strong electric field layer 601, and undergo secondary demulsification and aggregation under the action of the step-shaped electric field force. The crude oil that has undergone secondary desalting and dehydration continues to rise to the top of the electric desalter 5, and flows out of the electric desalter 5 along the oil collecting pipe 11 and the oil outlet pipe 7.

[0023] In order to verify the use effect of the present invention, the following use test was carried out: The properties of the crude oil used are shown in Table 1: Table 1

[0024] The two-stage series electric desalination process is adopted. The electric field area 6 of each electric desalination tank 5 is divided into three sections. Two feed distributors are arranged in parallel in each electric field area 6. They are connected to the feed main pipe 1 through their respective feed branch pipes 2. The process conditions adopted by each electric desalination tank 5 are shown in Table 2: Table 2 project Level 1 Level 2 Temperature / ℃ 150 150 Pressure / MPa 1.0 1.0 <![CDATA[Dosage of demulsifier / mg·kg -1 > 25 25 <![CDATA[Electric field strength / V·cm -1 > 1000 1200 Water injection volume / m% 5 4 Mixing strength / KPa 65 80 Test 1: The primary and secondary electric desalting tanks 5 both use the feed distributor disclosed in the present invention, the distance between the highest point of the feed distributor and the bottom surface of the electric field area 6 is 400 mm; the angle between the inverted trapezoidal slope of the feed cavity 303 and the horizontal plane is 30°; the diameter of the distribution holes 301 is 10 mm, and the sum of their cross-sectional areas is 1.1 times the flow cross-sectional area of ​​the feed main pipe 1; the interval of the corrugated plate 401 is 10 mm, and the angle between the regular corrugated plate 401 filler and the horizontal plane is 50°; The distance between the radial baffle 8 of the primary and secondary electric desalination tanks 5 and the axial boundary of the electric field area 6 is 20 mm; the distance between the axial baffle 9 and the radial boundary of the electric field area 6 is 20 mm; The crude oil before demulsification, washing water accounting for 5% of the weight of the crude oil and 25mg / kg of the oil-soluble demulsifier are mixed by a primary static mixer and a mixing valve at the same time. The mixing pressure difference of the mixing valve is 65KPa. The uniformly mixed oil-water mixture enters the primary electric desalter 5 along the feed main pipe 1, and then continuously enters the oil-water feed distributor through the feed branch pipe 2. The oil and water coming out of the distribution hole 301 and the dispersion hole 13 merge in the weak electric field layer 602, and then continue to move upward. Under the action of the strong electric field force with a field strength of 1000V / cm, the demulsified crude oil is deeply demulsified and agglomerated. After the secondary electric field force of the primary electric desalter 5 strengthens the demulsification and agglomeration, the crude oil flows out of the electric desalter 5 from the top of the electric desalter 5 along the oil collecting pipe 11 and the oil outlet pipe 7. The first desalted crude oil flowing out of the first-stage electric desalter 5 is mixed with 4% washing water in turn through the second-stage static mixer and the mixing valve. The mixing pressure difference of the mixing valve is 80KPa. The uniformly mixed oil-water mixture enters the second-stage electric desalter 5 along the feed main pipe 1, and completes the same desalting and dehydrating process as the first-stage electric desalter 5 under the field strength conditions described in Table 2; In this experiment, the salt content of the crude oil after secondary desalting and dehydration is 2.35 mg NaCl / L, the water content is 0.10%, and the water-cut oil content is 143 mg / L.

[0025] Test 2: The primary and secondary electric desalting tanks 5 both use the feed distributor disclosed in the present invention, the distance between the highest point of the feed distributor and the bottom surface of the electric field area 6 is 500 mm; the angle between the inverted trapezoidal slope of the feed cavity 303 and the horizontal plane is 70°; the diameter of the distribution holes 301 is 15 mm, and the sum of their cross-sectional areas is 1.5 times the flow cross-sectional area of ​​the feed main pipe 1; the interval of the corrugated plate 401 is 15 mm, and the angle between the regular corrugated plate 401 filler and the horizontal plane is 80°; The distance between the radial baffle 8 of the primary and secondary electric desalting tanks 5 and the axial boundary of the electric field area 6 is 50 mm; the distance between the axial baffle 9 and the radial boundary of the electric field area 6 is 50 mm; Other conditions and procedures were the same as those in Experiment 1; In this experiment, the salt content of the crude oil after secondary desalting and dehydration is 2.96 mg NaCl / L, the water content is 0.19%, and the water-cut oil content is 195 mg / L.

[0026] Test 3: The primary and secondary electric desalting tanks 5 both use the feed distributor disclosed in the present invention, the distance between the highest point of the feed distributor and the bottom surface of the electric field area 6 is 350 mm; the angle between the inverted trapezoidal slope of the feed cavity 303 and the horizontal plane is 45°; the diameter of the distribution holes 301 is 12 mm, and the sum of their cross-sectional areas is 1.3 times the flow cross-sectional area of ​​the feed main pipe 1; the interval of the corrugated plate 401 is 12 mm, and the angle between the regular corrugated plate 401 filler and the horizontal plane is 60°; The distance between the radial baffle 8 of the primary and secondary electric desalination tanks 5 and the axial boundary of the electric field area 6 is 25 mm; the distance between the axial baffle 9 and the radial boundary of the electric field area 6 is 25 mm; Other conditions and procedures were the same as those in Experiment 1.

[0027] In this embodiment, the salt content of the crude oil after secondary desalting and dehydration is 1.88 mg NaCl / L, the water content is 0.07%, and the water-cut oil content is 92 mg / L.

[0028] In order to compare the use effect of the electric desalting technology of the present invention with that of the traditional electric desalting device, under the condition that the crude oil, operating conditions and other internal components of the electric desalting tank 5 remain unchanged, the salt content of the crude oil after secondary desalting and dehydration is 3.85 mg NaCl / L, the water content is 0.22%, and the water-cut oil content is 267 mg / L; after comparison, it is not difficult to find that the present invention has a significant effect in strengthening the desalting and dehydration of crude oil.

[0029] The parts of the present invention that are not described in detail are prior art. It is obvious to those skilled in the art that the present invention is not limited to the details of the above-mentioned exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, no matter from which point of view, the above-mentioned embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is limited by the attached claims rather than the above description. Therefore, it is intended to include all changes within the meaning and scope of the equivalent elements of the claims in the present invention, and any figure marks in the claims should not be regarded as limiting the content of the claims involved.

Claims

1. A system for enhancing the desalting and dehydrating effect of crude oil, characterized by: The invention comprises a horizontal electric desalting tank (5), wherein the upper tank wall of the electric desalting tank (5) is provided with an oil outlet pipe (7), the lower tank wall of the electric desalting tank (5) is provided with a feed main pipe (1) and a drain pipe (10), and an electric field area (6) is provided in the center of the electric desalting tank (5); a feed distributor is provided below the electric field area (6), and the feed distributor comprises a plurality of distribution heads (3) arranged side by side at intervals and having an inner cavity, and a stuffing box (4) is provided in the center of the distribution head (3) for dividing the inner cavity into a distribution cavity (302) and a feed cavity (303) from top to bottom, The stuffing box (4) is provided with a plurality of corrugated plates (401) arranged side by side at intervals, the upper end and the lower end of the cavity between two adjacent corrugated plates (401) are respectively connected to the distribution cavity (302) and the feed cavity (303), the feed cavity (303) is connected to the feed main pipe (1) via the feed branch pipe (2), and the outer cavity wall of the distribution cavity (302) is provided with a plurality of distribution holes (301); the electric field area (6) is surrounded by a flow guide enclosure made of high temperature resistant electrical insulating material, so as to guide the oil and water materials entering from the feed main pipe (1) to pass through the electric field area (6).

2. The system for enhancing the desalting and dehydrating effect of crude oil according to claim 1, characterized in that: The electric field region (6) is a rectangular parallelepiped electric field formed by using flat plate electrodes, and the electric field region (6) is divided into a strong electric field layer (601) and a weak electric field layer (602) from top to bottom; the flow guide enclosure comprises two radial baffles (8) and two axial baffles (9) corresponding to the electric field region (6); both end plate edges of the radial baffles (8) extend along the plate surface and are sealed and fixed to the corresponding inner wall of the electric desalination tank (5); the upper side plate edge of the radial baffle (8) is folded outward and extended to be sealed and fixed to the corresponding head of the electric desalination tank (5); the two ends of the axial baffle (9) are respectively close to the two radial baffles (8); the upper side plate edge of the axial baffle (9) is folded outward and extended to be sealed and fixed to the corresponding tank wall of the electric desalination tank (5).

3. The system for enhancing the desalting and dehydrating effect of crude oil according to claim 2, characterized in that: A plurality of distribution pipes (12) arranged at intervals along the axial direction of the electric desalting tank (5) are fixed to the plate surface of the axial baffle (9) corresponding to the weak electric field layer (602); one end of the distribution pipe (12) is open and passes through the corresponding axial baffle (9); the other end of the distribution pipe (12) is closed and extends close to the center of the electric field area (6); and a plurality of dispersion holes (13) are provided on the wall of the distribution pipe (12) at intervals along the axial direction of the pipe body.

4. The system for enhancing the desalting and dehydrating effect of crude oil according to claim 2, characterized in that: A gap of less than or equal to 50 mm is left between the plate surfaces of the radial baffle (8) and the axial baffle (9) and the electric field region (6); and a support rod is provided between the plate surfaces of the radial baffle (8) and the axial baffle (9) away from the electric field region (6) and the tank wall of the electric desalination tank (5).

5. The system for enhancing crude oil desalting and dehydration effect according to claim 1, characterized in that: The surface of the corrugated plate (401) is provided with a hydrophilic layer, the distance between two adjacent corrugated plates (401) is 8 to 15 mm, and tear holes (402) are provided at the troughs of the corrugated plates (401).

6. The system for enhancing crude oil desalting and dehydration effect according to claim 1, characterized in that: Two corrugated plate groups are symmetrically arranged on both sides of the stuffing box (4), each corrugated plate group comprises a plurality of corrugated plates (401) spaced apart and arranged side by side, the angle between the corrugated plates (401) and the horizontal plane is 50 to 80 degrees, and a feed clamping cavity (403) communicating with the feed cavity (303) is provided between the two corrugated plate groups.

7. The system for enhancing crude oil desalting and dehydration effect according to claim 1, characterized in that: The distribution head (3) is a long strip structure along the length direction of the electric field region (6); the cross section of the feed cavity (303) is an inverted trapezoid; the feed branch pipe (2) is connected to the center of the bottom cavity wall of the feed cavity (303); the distribution cavity (302) comprises three cavities corresponding to the top surface and two side surfaces of the stuffing box (4), respectively; and the outer wall of each cavity is provided with a plurality of rows of distribution hole groups, and each row of distribution hole groups is provided with a plurality of distribution holes (301) evenly spaced along the length direction of the distribution head (3); and the total cross-sectional area of ​​all the distribution holes (301) is 1.1 to 1.5 times the flow cross-sectional area of ​​the feed main pipe (1).

8. The system for enhancing crude oil desalting and dehydration effect according to claim 1, characterized in that: The feed distributors are provided in plurality, and the distance between the distribution head (3) and the electric field region (6) of each feed distributor is greater than or equal to 350 mm.

9. The system for enhancing crude oil desalting and dehydration effect according to claim 1, characterized in that: The inner end of the oil outlet pipe (7) is connected to an oil collecting pipe (11) parallel to the electric field area (6), the lower wall of the oil collecting pipe (11) is provided with an oil collecting port, and the lower wall of the electric desalting tank (5) is provided with a manhole.

10. A method for using the system for enhancing crude oil desalting and dehydration effects as claimed in claim 3, characterized in that: The oil-water mixture formed by the enhanced mixed crude oil and washing water is fed from the feed main pipe (1), and then continuously enters the distribution head (3) of the feed distributor through the feed branch pipe (2), and passes through the stuffing box (4), where the first demulsification and agglomeration is achieved under the action of the regular corrugated plate (401) filler, wherein some small water droplets are aggregated into large water droplets, and then evenly distributed to the electric desalter (5) through the distribution holes (301); the large water droplets formed by the first agglomeration in the feed distributor fall into the water phase located at the lower part of the electric desalter (5) due to the density difference, and can be discharged from the drain pipe (10), and the remaining oil-water mixture with small water droplets is restricted by the radial baffle (8) and the axial baffle (9), and most of them move upward. After entering the weak electric field layer (602), a small portion of the oil-water mixture ascends along the space enclosed by the radial baffle (8), the axial baffle (9) and the inner wall of the electric desalter (5). Due to the closed restriction of the upper side of the radial baffle (8) and the axial baffle (9), it can only enter the middle of the weak electric field layer (602) through the dispersion holes (13) on the distribution pipe (12). After the two streams of oil-water mixture merge, they continue to ascend along the weak electric field layer (602) and enter the strong electric field layer (601). Under the action of the electric field force that changes in a step-shaped manner, secondary demulsification and aggregation are carried out. After the secondary desalting and dehydration, the crude oil continuously rises to the top of the electric desalter (5) and flows out of the electric desalter (5) along the oil collecting pipe (11) and the oil outlet pipe (7).

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