An electric dehydration device for crude oil and an electric dehydration method using the device

Abstract

The present invention relates to a crude oil electro-dehydration device and an electro-dehydration method using the device, which comprises a treatment tank body. The treatment tank body has a liquid distribution area, a primary electro-dehydration area, a primary sedimentation area, a secondary electro-dehydration area, a secondary sedimentation area and an oil storage area. An insulating plate group and a bare plate group are respectively arranged in the primary electro-dehydration area and the secondary electro-dehydration area, and both are respectively composed of a plurality of type-I plate bodies and type-II plate bodies. The type-I plate body includes a central conductor layer, a semiconductor sub-outer layer and an insulating outer layer which are sequentially arranged from the inside to the outside. A voltage conversion device is arranged on one side of each type-I plate body and type-II plate body. The voltage conversion devices corresponding to the type-I plate body and the type-II plate body are respectively electrically connected to an external AC power supply and a DC power supply. The electro-dehydration device of the technical solution can avoid the breakdown of the insulating outer layer, thereby preventing the short circuit of the device, and enable the voltage to be converted inside the device, ensuring excellent safety during the electro-dehydration process.

Description

Technical Field

[0001] The present invention relates to the technical field of crude oil electro-dehydration, and more specifically, to a crude oil electro-dehydration device and an electro-dehydration method using the device. Background Art

[0002] During the oil extraction process, the produced crude oil is water-containing emulsified crude oil. With the increase of the mining years and water injection development, the water content of the emulsified crude oil will also continuously increase. Therefore, it is necessary to dehydrate the crude oil. During the dehydration process, sewage, impurities, etc. are separated from the oil-water emulsified crude oil, so that the volume of the emulsified crude oil is continuously reduced and the purity is continuously improved. Finally, high-quality commercial oil is obtained. For example, using the density difference between crude oil and water, the water droplets contained in the crude oil are settled and separated from the crude oil under the action of gravity in a settling tank. However, when separating by the method of gravity settling, there are problems that the crude oil stays in the tank for too long and the separation rate is low. While using the electro-dehydration method can well solve the problems existing in sedimentation dehydration. During the electro-dehydration process, the emulsified crude oil is placed in a high-voltage direct current or alternating current electric field generated by the electrode plate group of the crude oil electro-dehydration device. By using the action of the electric field on the water droplets in the crude oil, the water droplets are deformed and electrostatic force is generated. Under the action of the electrostatic force, the movement speed of the water droplets increases and the kinetic energy increases. Furthermore, the emulsified film on the surface of the emulsified crude oil is continuously impacted, so that the mechanical strength of the emulsified film is reduced until it breaks, and the high-speed moving water droplets are promoted to coalesce with each other into water droplets with larger particle sizes. With the help of the density difference between oil and water, they settle from the crude oil under the action of gravity to achieve separation.

[0003] During the process of dehydrating crude oil using a traditional crude oil electro-dehydration device, the problem of short circuit often occurs. This is because the electrode plate group in the traditional crude oil dehydration device is made of metal plate parts and is completely immersed in the emulsified crude oil during dehydration. Due to the high water content, the emulsified crude oil has strong conductivity. When a high voltage is applied to the metal plate parts, it will cause an increase in the leakage current between the positive and negative metal plate parts, resulting in a short circuit. At the same time, the electric field formed between the metal plate parts is damaged, so that the water droplets in the emulsified crude oil cannot effectively coalesce, affecting the final oil-water separation effect.

[0004] Aiming at the short circuit problem that is easy to occur in the process of electrical dehydration of crude oil by traditional crude oil electrical dehydration equipment, a Chinese patent with publication number CN110878219A and patent name "A high water content crude oil electrical dehydration device" discloses a new type of crude oil electrical dehydration equipment, which specifically includes a shell, a packing area is arranged near the crude oil inlet side of the shell, a grid is arranged between the packing area and the oil outlet, the grid is fixed on the bottom surface of the shell, and electrodes are arranged in the interval of the grid. The electrodes are suspended by an electrode frame to form an electrical dehydration electric field between the grid and the electrode. The surface of the electrode is wrapped with a film. A polytetrafluoroethylene coating is added, the electrode frame is fixed on the top of the shell, one end of the grid close to the filler area is connected to the ground terminal of the power supply, and the electrode is connected to the positive electrode of the power supply through the electrode frame. In the crude oil electric dehydration equipment with the above structure, the electric dehydration area is divided into multiple parts by partitions, and an uneven electric field is formed by different-diameter electrodes between the partitions, so that the strength of the electric field in the electric dehydration device matches the water content, which can improve the electric dehydration efficiency of crude oil with high water content. At the same time, the polytetrafluoroethylene insulating coating arranged outside the electrode can insulate the electrodes from each other to prevent the electrodes from directly contacting the emulsified crude oil and causing short circuit.

[0005] However, the electrodes of the crude oil electric dehydration device still have the risk of short circuit. Since there are corners on the electrode surface and the curvature at the corners is large, when high voltage is applied to the electrode, the charge on the electrode surface is easy to accumulate here, resulting in tip discharge. In addition, the thickness of the polytetrafluoroethylene in the coating structure is thin and the density is low. When tip discharge occurs, the insulation protection formed by the polytetrafluoroethylene coating is easily destroyed, so that the internal electrode is exposed to the outside and directly contacts with the emulsified crude oil, causing a short circuit. At the same time, compared with traditional crude oil electric dehydration equipment, it still uses external high-voltage power transmission. During the power transmission process, high-voltage leakage is easy to occur due to damage caused by aging of the transmission line or other reasons, resulting in great risks in the electric dehydration process. Summary of the invention

[0006] In view of the above situation, in order to overcome the problem that the insulating coating on the surface of the electrode of the above-mentioned existing crude oil electric dehydration equipment is easily broken down during the electric dehydration process, causing the internal electrode to be exposed to the outside and directly contact with the emulsified crude oil to cause a short circuit, and at the same time, the high-voltage power transmission method is prone to leakage, so there is a great risk in the electric dehydration process. The purpose of the present invention is to provide a crude oil electric dehydration equipment and method that can avoid the insulation layer on the surface of the electrode from being broken down, thereby preventing the equipment from short-circuiting, and converting the voltage inside the equipment, eliminating high-voltage power transmission, and ensuring that the electric dehydration process has excellent safety.

[0007] In order to achieve the above object, the technical solution of the present invention is:

[0008] An electro-dehydration device for crude oil, which comprises a processing tank body. An oil inlet pipe, an oil outlet pipe and a drain pipe are connected to the processing tank body. The processing tank body has a liquid distribution area, a primary electro-dehydration area, a primary sedimentation area, a secondary electro-dehydration area, a secondary sedimentation area and an oil storage area which are distributed in sequence from front to back and are connected and communicated with each other. The liquid distribution area is connected to the oil inlet pipe and is internally provided with a liquid distributor. The primary electro-dehydration area, the primary sedimentation area, the secondary electro-dehydration area and the secondary sedimentation area are all connected to the drain pipe, and an insulating plate group and a bare plate group are respectively arranged in the primary electro-dehydration area and the secondary electro-dehydration area. The insulating plate group and the bare plate group are respectively composed of a number of type-I plate bodies and type-II plate bodies. Each type-I plate body and type-II plate body are distinguished between positive and negative poles, and the negative type-II plate body is grounded. The type-I plate body includes a central conductor layer, a semiconductor sub-outer layer and an insulating outer layer which are sequentially arranged from inside to outside. The central conductor layer and the semiconductor sub-outer layer are both wrapped in the insulating outer layer. A voltage conversion device is arranged on one side of each type-I plate body and type-II plate body. The voltage conversion devices corresponding to the type-I plate body and the type-II plate body are respectively electrically connected to an external AC power supply and a DC power supply. The oil storage area is connected to the oil outlet pipe.

[0009] Preferably, the material of the central conductor layer is metal, the semiconductor sub-outer layer is a coating structure, which is coated on the surface of the central conductor layer and adopts an anti-static semiconductor coating, and the insulating outer layer is epoxy resin formed by vacuum casting or fluorine material formed by die-casting as a whole.

[0010] Preferably, the voltage conversion device includes a transformer, a protective shell and a conductive rod. The transformer is arranged in the protective shell. The conductive rod is arranged at one end of the protective shell and passes through the protective shell to be connected to the output end of the transformer. The conductive rod of the voltage conversion device corresponding to the type-I plate body penetrates through the insulating outer layer to be connected to the central conductor layer, and an external wiring cable penetrates through the other end of the protective shell to be connected to the transformer.

[0011] Preferably, a voltage monitoring module is further arranged at the output end of the transformer, and the voltage monitoring module has a voltage feedback circuit.

[0012] Preferably, the protective shell includes a sleeve body, a positioning end cover and a wiring end cover. The positioning end cover and the wiring end cover are respectively arranged at the front and rear ends of the sleeve body. The sleeve body corresponding to the type-I plate body is of the same material as the insulating outer layer and is integrally formed with the insulating outer layer by casting or die-casting. A clamping groove opposite to the conductive rod is opened on the positioning end cover and is clamped on the type-I plate body and the type-II plate body through the clamping groove. A wiring hole for the external wiring cable to pass through is opened on the wiring end cover.

[0013] Preferably, positioning brackets for fixing the insulating plate group and the bare plate group are also provided in the primary electro-dehydration area and the secondary electro-dehydration area. The positioning brackets include a support framework, a support cover, a support seat, and a support plate. At least two groups of support frameworks are configured and are all connected to the treatment tank body. The support cover and the support seat are respectively arranged on the opposite surfaces of two adjacent support frameworks. The support plates are arranged at intervals between the support cover and the support seat. The parts of the support cover and the support seat between two adjacent support plates are used for fixing the main body of the type-I plate and the main body of the type-II plate.

[0014] Preferably, a plurality of opposite top chutes and bottom chutes are respectively formed in the support cover and the support seat. One ends of the top chutes and the bottom chutes are closed, and the other ends are respectively communicated with the side walls of the support cover and the support seat. The upper and lower ends of the main body of the type-I plate and the main body of the type-II plate are respectively slidably connected in the top chutes and the bottom chutes.

[0015] Preferably, at least one sampling port is formed in the treatment tank body opposite to and communicated with the primary sedimentation area and the secondary sedimentation area. Each sampling port is distributed at different heights. Each sampling port is connected to a sampling discharge pipe, and a sampling valve is connected to the sampling discharge pipe.

[0016] Preferably, a monitoring assembly is also provided in the treatment tank body. The monitoring assembly includes a liquid level gauge arranged in the liquid distribution area and the oil storage area, and a water content monitor arranged in the oil outlet of the secondary sedimentation area.

[0017] An electro-dehydration method using the above crude oil electro-dehydration equipment includes the following steps:

[0018] S1: The emulsified crude oil mined is discharged into the liquid distribution area of the treatment tank body through an inlet pipe, and after the flow rate of the emulsified crude oil is stabilized by a liquid distributor, it is discharged into the primary electro-dehydration area;

[0019] S2: In the primary electro-dehydration area, the low-voltage electricity provided by an external AC power supply is transmitted to the voltage conversion device corresponding to each main body of the type-I plate in the insulating plate group through an external connecting cable. The voltage conversion device converts the low-voltage electricity into high-voltage electricity and applies it to the central conductor layer of the main body of the type-I plate, generating a stable AC electric field between the mutually insulated main bodies of the type-I plates, and preliminarily electro-dehydrating the emulsified crude oil in a way of oscillating coalescence. After completion, the coalesced water is discharged through a drain pipe, and the crude oil overflows to the primary sedimentation area;

[0020] S3: The emulsified crude oil with reduced water content undergoes preliminary gravity sedimentation dehydration in the primary sedimentation area. After completion, the coalesced water is discharged through a drain pipe, and the crude oil overflows to the secondary electro-dehydration area for secondary electro-dehydration;

[0021] S4: In the secondary electro-dehydration zone, the low-voltage power supplied by the external DC power supply is transmitted through the external wiring cables to the voltage conversion devices corresponding to the main bodies of the second-type plates in the bare plate group. The voltage conversion devices convert it into high-voltage power and apply it to the central conductor layer of the main bodies of the second-type plates, generating a DC electric field between the main bodies of the second-type plates. The emulsified crude oil is subjected to secondary electro-dehydration in the way of electrophoresis coalescence. After completion, the coalesced water is discharged through the drain pipe, and the crude oil overflows to the secondary sedimentation zone.

[0022] S5: The emulsified crude oil with further reduced water content after secondary electro-dehydration undergoes secondary gravity sedimentation dehydration in the secondary sedimentation zone. After completion, high-purity commercial oil is obtained. The coalesced water is discharged through the drain pipe, and the crude oil overflows to be stored in the oil storage area.

[0023] Compared with the prior art, the advantages of the present invention are as follows:

[0024] (1) The semiconductor sub-outer layer of each main body of the first-type plates in the insulating plate group serves as an intermediate medium between the outer layer of the insulator and the central conductor layer. When high-voltage power is applied to the main body of the plate, an electric field is formed around the main body of the plate. Utilizing the characteristics of the semiconductor sub-outer layer material, it ensures a more uniform distribution of charges, thereby preventing the direct wrapping of the outer layer of the insulator outside the metal conductor and avoiding the problem of tip discharge and breakdown of the insulating layer caused by charge accumulation. At the same time, it can also ensure the generation of a stable electric field around the insulating plate group, and the electric field intensity can exceed 5 to 8 times that of the traditional crude oil electro-dehydration equipment. Therefore, the efficiency of the electro-dehydration process can be significantly improved, and the equipment cost can be effectively reduced.

[0025] (2) Each main body of the first-type plates in the insulating plate group and each main body of the second-type plates in the bare plate group are each corresponding to a voltage conversion device. The voltage converter is located in the electro-dehydration equipment along with the main body of the plate. Therefore, the location of voltage conversion is inside the treatment tank, and the external wiring cables only transmit low-voltage power. Thus, the risk of high-voltage power transmission is eliminated, greatly improving the safety of the electro-dehydration process of the electro-dehydration equipment of the present invention. Even if the external wiring cables are damaged and leak due to aging of the transmission line or other reasons, the harm to the surrounding equipment and personnel can be reduced.

[0026] (3) Through the configuration of two insulating plate groups and bare plate groups with different application scenarios, the crude oil electro-dehydration equipment of the present invention can be applicable to the treatment of emulsified crude oil with different water contents. The emulsified crude oil with high water content can be reasonably treated by the insulating plate group to save subsequent treatment steps, thereby effectively reducing the overall energy consumption and volume of the equipment, and enabling the equipment of the present invention to have a flexible treatment space. If the emulsified crude oil to be treated has a low water content itself, the bare plate group can be directly selected for electro-dehydration treatment. Description of the Drawings

[0027] Figure 1It is a schematic diagram of the overall structure of the crude oil electro-dehydration equipment of the present invention;

[0028] Figure 2 It is a schematic diagram of the overall structure of the liquid distribution area and the internal liquid distributor of the crude oil electro-dehydration equipment of the present invention;

[0029] Figure 3 It is a schematic diagram of the overall structure of the primary electro-dehydration area and the type-I plate electrode body and positioning bracket inside the crude oil electro-dehydration equipment of the present invention;

[0030] Figure 4 It is a schematic diagram of the overall structure of the type-I plate electrode body and its positioning bracket of the crude oil electro-dehydration equipment of the present invention;

[0031] Figure 5 It is a schematic diagram of the overall structure of the type-I plate electrode body and its voltage conversion device of the crude oil electro-dehydration equipment of the present invention;

[0032] Figure 6 It is an exploded structure diagram of the type-I plate electrode body and its voltage conversion device of the crude oil electro-dehydration equipment of the present invention;

[0033] Figure 7 It is a partially enlarged sectional structure diagram of the type-I plate electrode body of the crude oil electro-dehydration equipment of the present invention;

[0034] Figure 8 It is a schematic diagram of the overall structure of the primary sedimentation area of the crude oil electro-dehydration equipment of the present invention;

[0035] Figure 9 It is a schematic diagram of the overall structure of the secondary electro-dehydration area and the type-II plate electrode body and positioning bracket inside the crude oil electro-dehydration equipment of the present invention;

[0036] Figure 10 It is a schematic diagram of the overall structure of the type-II plate electrode body and its positioning bracket of the crude oil electro-dehydration equipment of the present invention;

[0037] Figure 11 It is a schematic diagram of the overall structure of the positioning bracket of the crude oil electro-dehydration equipment of the present invention;

[0038] Figure 12 It is of the present invention Figure 11 The enlarged structure diagram of part A;

[0039] Figure 13 It is a schematic diagram of the overall structure of the secondary sedimentation area and the oil storage area of the crude oil electro-dehydration equipment of the present invention.

[0040] As shown in the figure:

[0041] 1. Processing tank body; 101. Liquid distribution area; 102. Primary electro-dehydration area; 103. Primary sedimentation area; 104. Secondary electro-dehydration area; 105. Secondary sedimentation area; 106. Oil storage area; 2. Inlet pipe; 3. Outlet pipe; 4. Drain pipe; 5. Liquid distributor; 6. Type-I plate body; 601. Central conductor layer; 602. Semiconductor sub-outer layer; 603. Insulating outer layer; 7. Type-II plate body; 8. Voltage conversion device; 801. Transformer; 802. Conductive rod; 803. Sleeve; 804. Positioning end cap; 804a. Card slot; 805. Wiring end cap; 805a. Wiring hole; 9. Positioning bracket; 901. Support skeleton; 902. Support cover; 902a. Top chute; 903. Support seat; 903a. Bottom chute; 904. Support plate; 10. Sampling drain pipe; 11. Sampling valve; 12. Liquid level gauge; 13. Water cut monitor. Detailed implementation manners

[0042] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the present invention is usually placed during use. It is only for the convenience of simplifying the description, rather than indicating or implying that the orientation must have a specific orientation and specific orientation structure and operation. Therefore, it should not be construed as a limitation to the present invention.

[0044] Such as Figures 1 to 3 、 Figure 8 、 Figure 9 and Figure 13As shown in the figure, an electric dehydration device for crude oil includes a processing tank body 1. An oil inlet pipe 2, an oil outlet pipe 3 and a drain pipe 4 are connected to the processing tank body 1, which are respectively used to input the emulsified crude oil to be electrically dehydrated into the processing tank body 1, discharge the coalesced water after electric dehydration and sedimentation treatment from the processing tank body 1, and output the high-purity crude oil obtained after final treatment from the processing tank body 1. Inside the processing tank body 1, there are a liquid distribution area 101, a primary electric dehydration area 102, a primary sedimentation area 103, a secondary electric dehydration area 104, a secondary sedimentation area 105 and an oil storage area 106 distributed in sequence from front to back. The liquid distribution area 101, the primary electric dehydration area 102, the primary sedimentation area 103, the secondary electric dehydration area 104, the secondary sedimentation area 105 and the oil storage area 106 are connected in sequence. The crude oil entering the liquid distribution area 101 and then entering the primary electric dehydration area 102 from the liquid distribution area 101 is emulsified crude oil with a high water content. In the primary electric dehydration area 102, the emulsified crude oil with a high water content is preliminarily electrically dehydrated. Based on the density difference between oil and water, the formed coalesced water settles under the action of gravity. The crude oil and the unseparated small water droplets therein are located in the upper layer. The coalesced water below is discharged through the drain pipe 4, and the emulsified crude oil with a reduced water content above overflows into the primary sedimentation area 103 for further sedimentation dehydration to further reduce the water content of the emulsified crude oil. Then it overflows into the secondary electric dehydration area 104 for secondary electric dehydration of the emulsified crude oil with a low water content. After secondary sedimentation dehydration, the emulsified crude oil finally obtains high-purity commercial oil meeting the standards and overflows into the oil storage area 106 for storage. Among them, the liquid distribution area 101 is connected to the oil inlet pipe 2, and a liquid distributor 5 is provided inside the liquid distribution area 101. The liquid distributor 5 can prevent the emulsified crude oil with a high water content entering the liquid distribution area 101 from flowing too fast and causing liquid short-circuit when entering the primary electric dehydration area 102. It should be mentioned that the liquid distributor 5, that is, the liquid distributor, is used to evenly discharge the emulsified crude oil into the primary electric dehydration area 102. It is a common component in the prior art, so it will not be elaborated here. The primary electric dehydration area 102, the primary sedimentation area 103, the secondary electric dehydration area 104 and the secondary sedimentation area 105 are all connected to the drain pipe 4. The oil storage area 106 is connected to the oil outlet pipe 3. An insulating plate group and a bare plate group are respectively provided in the primary electric dehydration area 102 and the secondary electric dehydration area 104. When a voltage is applied, the insulating plate group and the bare plate group generate an electric field to electrically dehydrate the emulsified crude oil discharged into the primary electric dehydration area 102 and the secondary electric dehydration area 104. The insulating plate group and the bare plate group are respectively composed of a number of type I plate bodies 6 and type II plate bodies 7. Each type I plate body 6 and type II plate body 7 are distinguished between positive and negative poles, and the type II plate body 7 as the negative pole is grounded. It can be understood that the surface of the type II plate body 7 belonging to the bare plate group is a conductor without other substances wrapped. Since the emulsified crude oil is electrically dehydrated by the insulating plate group in the primary electric dehydration area 102 and undergoes secondary sedimentation dehydration in the primary sedimentation area 103, its water content has been greatly reduced. When a conductor is immersed in it, no short-circuit will occur.Therefore, the bare electrode plate group can be directly used for electro-dehydration. Through the configurations of the insulating electrode plate group and the bare electrode plate group with different application scenarios, the crude oil electro-dehydration equipment of the present invention can be applicable to the treatment of emulsified crude oil with different water contents. The emulsified crude oil with high water content can be reasonably treated by the insulating electrode plate group to save the subsequent treatment steps, thereby effectively reducing the overall energy consumption and volume of the equipment, and enabling the equipment of the present invention to have a flexible treatment space. If the emulsified crude oil to be treated has a low water content itself, the bare electrode plate group can be directly selected for electro-dehydration treatment. The type-I electrode plate body 6 includes a central conductor layer 601, a semiconductor sub-outer layer 602, and an insulating outer layer 603 arranged in sequence from the inside to the outside. The central conductor layer 601 and the semiconductor sub-outer layer 602 are both enclosed in the insulating outer layer 603, that is, the central conductor layer 601 is located at the center of the electrode plate body, the semiconductor sub-outer layer 602 is located outside the central conductor layer 601 and wraps around the central conductor layer 601, and the insulating outer layer 603 is located outside the semiconductor sub-outer layer 602, thereby wrapping around the semiconductor sub-outer layer 602 and the central conductor layer 601. Under the action of the insulating outer layer 603, the electrode plates are insulated from each other. When the emulsified crude oil is discharged into the primary electro-dehydration area 102, the insulating electrode plate group is immersed in the emulsified crude oil. The type-I electrode plate bodies 6 of the insulating electrode plate group that are insulated from each other will not conduct electricity with the water droplets in the emulsified crude oil to generate leakage current, thereby avoiding short-circuit problems during the electro-dehydration process. The semiconductor sub-outer layer 602 located between the central conductor layer 601 and the insulating outer layer 603 is used as an intermediate medium mainly for protecting the insulating outer layer 603. Specifically, when high-voltage electricity is applied to the type-I electrode plate body 6, due to the characteristics of the semiconductor material in the semiconductor sub-outer layer 602, the binding effect of its atomic nucleus on electrons is stronger than that of the central conductor layer 601. Compared with the central conductor layer 601, which has only a small number of movable free electrons, it is not easy to cause a high concentration of charges, making the charge distribution more uniform, and avoiding the problem that the insulating outer layer 603 is directly wrapped outside the central conductor layer 601, and a large amount of charges accumulate to generate tip discharge and break down the insulating outer layer 603 when high-voltage electricity is applied. At the same time, it can also ensure the generation of a stable electric field around the insulating electrode plate group, and the electric field intensity can exceed 5 to 8 times that of the traditional crude oil electro-dehydration equipment, thereby significantly improving the efficiency of the electro-dehydration process and effectively reducing the equipment cost. In addition, a voltage conversion device 8 is provided on one side of each type-I electrode plate body 6 and type-II electrode plate body 7. The voltage conversion devices 8 on the type-I electrode plate body 6 and the type-II electrode plate body 7 are respectively connected to an external AC power supply and a DC power supply through external connection cables. The voltage conversion device 8 is used to convert the high-voltage electricity transmitted from the outside into low-voltage electricity and directly apply it to the insulating electrode plate group and the bare electrode plate group to generate an electric field. It can be understood that since both the insulating electrode plate group and the bare electrode plate group are located inside the treatment tank 1, the place for voltage conversion is inside the treatment tank 1, and the external connection cables only transmit low-voltage electricity, thus eliminating the risk of high-voltage power transmission.The safety of the electric dehydration process of the electric dehydration equipment of the present invention is greatly improved. Even if the external cable is damaged due to aging of the transmission line or other reasons and leakage occurs, the damage to surrounding equipment and personnel can be reduced. When the low-voltage electricity provided by the external AC power supply is transmitted to the voltage conversion device 8 corresponding to each type-one plate body 6 of the insulated plate group through the external cable, and converted into high-voltage electricity, and then applied to the central conductor layer 601 of the type-one plate body 6, a stable AC electric field is generated between the mutually insulated type-one plate bodies 6, and then the emulsified crude oil is preliminarily electrically dehydrated in the form of oscillation agglomeration. Under the action of the external DC power supply, a DC electric field is formed around the bare plate group, and then the emulsified crude oil is secondary electrically dehydrated in the form of electrophoresis agglomeration.

[0045] like Figures 5 to 7 As shown, the material of the central conductor layer 601 of the type-I electrode body 6 is metal, and a copper plate made of copper material with lower cost can be preferably selected. The semiconductor sub-outer layer 602 is a coating structure, which is coated on the surface of the central conductor layer 601. In the present invention, the semiconductor sub-outer layer 602 adopts an anti-static semiconductor coating, which can prevent the insulator outer layer 603 from generating static electricity, thereby improving the safety of crude oil electric dehydration production. The material of the insulator outer layer 603 is an epoxy resin formed as an integral part by vacuum casting. The advantage of this molding method is that it can eliminate the air bubbles retained between the insulator outer layer 603 and the internal central conductor layer 601 and the semiconductor sub-outer layer 602, thereby ensuring the uniform density of the type-I electrode body 6, so that its structural strength and sealing can be significantly improved. In addition, the material of the insulator outer layer 603 can also be selected from fluorine materials, such as tetrafluoroethylene, and the insulator outer layer 603 using fluorine materials is integrally formed by die-casting.

[0046] like Figure 5 and Figure 6 As shown, the voltage conversion device 8 includes a transformer 801, a protective shell and a conductive rod 802. The transformer 801 is a core component of the voltage conversion device 8 for high and low voltage conversion. The transformer 801 is arranged in a relatively closed protective shell and protected by the protective shell to reduce interference from factors such as external impact to ensure that the normal service life of the transformer 801 is not affected. The conductive rod 802 is made of metal material, which is arranged at one end of the protective shell, and passes through the protective shell to be connected to the output end of the transformer 801, and at the same time passes through the insulating outer layer 603 of the plate body to be connected to the central conductor layer 601. More specifically, a conductive groove is opened at one end of the conductive rod 802 away from the transformer 801, and the central conductor layer 601 of the plate body is inserted in the conductive groove. After the transformer 801 converts the low voltage into a high voltage, it is applied to the central conductor layer 601 of the plate body through the conductive rod 802, so that an electric field is generated around the plate body. The other end of the external cable passes through the protective shell and is connected to the transformer 801, which is used to transmit the low voltage to the transformer 801.

[0047] Furthermore, a voltage monitoring module is also provided at the output end of the transformer 801. The voltage monitoring module has a voltage feedback circuit, which is used to monitor the voltage on the corresponding type-I plate body 6 and type-II plate body 7 in real time. When the voltage between the electrode plates is abnormal, the operation of the transformer 801 is automatically cut off to avoid safety accidents caused by abnormal voltage.

[0048] As Figure 5 and Figure 6 shown, the protective housing includes a sleeve body 803, a positioning end cover 804, and a wiring end cover 805. The positioning end cover 804 and the wiring end cover 805 are respectively arranged at the front and rear ends of the sleeve body 803, and together with the sleeve body 803, they form a relatively enclosed space. The sleeve body 803 corresponding to the type-I plate body 6 is made of the same material as the outer insulating layer 603 and is integrally formed with the outer insulating layer 603 by casting or die-casting. The specific forming process is determined by the material of the outer insulating layer 603. A clamping groove 804a opposite to the conductive rod 802 is provided on the positioning end cover 804, and it is clamped to the type-I plate body 6 and the type-II plate body 7 through the clamping groove 804a, and then is secondarily connected in an insertion manner. It can be understood that after passing through the clamping groove 804a, the conductive rod 802 is connected to the central conductor layer 601 in the plate body. A wiring hole 805a for the external wiring cable to pass through is provided on the wiring end cover 805.

[0049] As Figure 3 、 Figure 4 、 Figures 9 to 12As shown, a positioning bracket 9 for fixing the insulated electrode plate group and the bare electrode plate group is also provided in the primary electro-dehydration area 102 and the secondary electro-dehydration area 104. The positioning bracket 9 is directly connected to the treatment tank body 1 to ensure that the positions of the insulated electrode plate group, the bare electrode plate group and the treatment tank body 1 are relatively fixed. Specifically, the positioning bracket 9 includes a support frame 901, a support cover 902, a support seat 903 and a support plate 904. There are at least two groups of support frames 901, and each support frame 901 is arranged at intervals in the longitudinal direction and is connected to the treatment tank body 1. The support cover 902 and the support seat 903 are respectively arranged on the opposite surfaces of two adjacent support frames 901, that is, the support cover 902 and the support seat 903 also remain at intervals. The support plate 904 is arranged between the support cover 902 and the support seat 903, and each support plate 904 remains at intervals. The parts of the support cover 902 and the support seat 903 between two adjacent support plates 904 form a storage space, and each storage space is used to fix a type-I electrode plate body 6 and a type-II electrode plate body 7. Under the action of the support plate 904, the fixed positive type-I electrode plate body 6, type-II electrode plate body 7 are separated from the negative type-I electrode plate body 6 and type-II electrode plate body 7. Based on the above settings, the number of type-I electrode plate bodies 6 and type-II electrode plate bodies 7 arranged is determined by the lengths of the support frame 901, the support cover 902 and the support seat 903, so that the positioning bracket 9 can fix the insulated electrode plate group and the bare electrode plate group with a large number of type-I electrode plate bodies 6 and type-II electrode plate bodies 7.

[0050] As Figure 3 , Figure 4 , Figures 9 to 12As shown in the figure, a number of opposite top sliding grooves 902a and bottom sliding grooves 903a are respectively formed on the support cover 902 and the support base 903. One end of the bottom sliding groove 903a and the top sliding groove 902a is closed, and the other end communicates with the side walls of the support cover 902 and the support base 903 respectively. The upper and lower ends of the type-I plate body 6 and the type-II plate body 7 are respectively inserted into the opening sides of the top sliding groove 902a and the bottom sliding groove 903a, and are fixed to the top sliding groove 902a and the bottom sliding groove 903a by sliding. The closed ends of the top sliding groove 902a and the bottom sliding groove 903a can prevent the type-I plate body 6 and the type-II plate body 7 from sliding out of position. Based on the above settings, the type-I plate body 6 and the type-II plate body 7 are detachably fixed to the support cover 902 and the support base 903, so that during the actual electro-dehydration process, according to the difference in the water content of the emulsified crude oil entering the primary electro-dehydration area 102 and the secondary electro-dehydration area 104, the number of the type-I plate body 6 and the type-II plate body 7 in the insulating plate group and the bare plate group can be flexibly adjusted. When the water content of the emulsified crude oil is low, the number of the type-I plate body 6 and the type-II plate body 7 can be reduced by sliding and extracting. At this time, the distance between adjacent type-I plate body 6 and type-II plate body 7 is enlarged, and the generated electric field intensity is correspondingly reduced. When the water content of the emulsified crude oil is high, the type-I plate body 6 and the type-II plate body 7 can be added to strengthen the generated electric field intensity.

[0051] As Figure 1 shown in the figure, at least one sampling port is formed on the treatment tank body 1 opposite to and communicating with the primary sedimentation area 103 and the secondary sedimentation area 105, which is used to regularly monitor the sedimentation status of the emulsified crude oil in the primary sedimentation area 103 and the secondary sedimentation area 105. Each sampling port is distributed at different heights, so as to be able to perform stratified sampling. Each sampling port is connected to a sampling drain pipe 10. The sampling drain pipe 10 can discharge the emulsified crude oil in the primary sedimentation area 103 and the secondary sedimentation area 105 as a test sample, and a sampling valve 11 is connected to the sampling drain pipe 10, and the on-off of the sampling drain pipe 10 is controlled by the sampling valve 11.

[0052] As Figure 1 shown in the figure, a monitoring component is further provided in the treatment tank body 1. The monitoring component includes a liquid level gauge 12 provided in the liquid distribution area 101 and the oil storage area 106, which is convenient for the operator to perform liquid inlet control and liquid outlet control when the emulsified crude oil enters the liquid distribution area 101 or is discharged from the oil storage area 106. In addition, it also includes a water content monitor 13 provided in the oil outlet of the secondary sedimentation area 105. The water content monitor 13 is convenient for the operator to monitor the water content of the emulsified crude oil flowing in in real time, and when the water content exceeds the standard, the water content monitor 13 can issue an alarm to prompt the operator, so as to more strictly control the electro-dehydration process of the electro-dehydration equipment of the present invention.

[0053] Combined with Figures 1 to 13, the specific electro-dehydration method using the above crude oil electro-dehydration equipment includes the following steps:

[0054] S1: The emulsified crude oil extracted is discharged into the liquid distribution area 101 of the treatment tank body 1 through the oil inlet pipe 2, and after the flow rate of the emulsified crude oil is stabilized by the liquid distributor 5, it is discharged into the primary electro-dehydration area 102;

[0055] S2: In the primary electro-dehydration area 102, the low-voltage electricity provided by the external AC power supply is transmitted to the voltage conversion device 8 corresponding to each type-I plate body 6 of the insulated plate group through the external connection cable. The voltage conversion device 8 converts it into high-voltage electricity and applies it to the central conductor layer 601 of the type-I plate body 6, generating a stable AC electric field between the mutually insulated type-I plate bodies 6 to conduct primary electro-dehydration on the emulsified crude oil in the way of oscillating coalescence. After completion, the coalesced water is discharged through the drain pipe 4, and the crude oil overflows to the primary sedimentation area 103;

[0056] S3: The emulsified crude oil with reduced water content undergoes primary gravity sedimentation dehydration in the primary sedimentation area 103. After completion, the coalesced water is discharged through the drain pipe 4, and the crude oil overflows to the secondary electro-dehydration area 104 for secondary electro-dehydration;

[0057] S4: In the secondary electro-dehydration area 104, the low-voltage electricity provided by the external DC power supply is transmitted to the voltage conversion device 8 corresponding to each type-II plate body 7 of the bare plate group through the external connection cable. The voltage conversion device 8 converts it into high-voltage electricity and applies it to the central conductor layer 601 of the type-II plate body 7, generating a DC electric field between the type-II plate bodies 7 to conduct secondary electro-dehydration on the emulsified crude oil in the way of electrophoresis coalescence. After completion, the coalesced water is discharged through the drain pipe 4, and the crude oil overflows to the secondary sedimentation area 105;

[0058] S5: The emulsified crude oil with further reduced water content after secondary electro-dehydration undergoes secondary gravity sedimentation dehydration in the secondary sedimentation area 105. After completion, high-purity commercial oil is obtained, the coalesced water is discharged through the drain pipe 4, and the crude oil overflows to the oil storage area 106 for storage.

[0059] The above embodiments and descriptions in the specification only illustrate the principle and the best embodiments of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed.

Claims

1. An electric dehydration device for crude oil, which comprises a processing tank body (1), and an oil inlet pipe (2), an oil outlet pipe (3) and a drain pipe (4) are connected to the processing tank body (1). Characterized in that the processing tank body (1) has a liquid distribution area (101), a primary electric dehydration area (102), a primary sedimentation area (103), a secondary electric dehydration area (104), a secondary sedimentation area (105) and an oil storage area (106) which are distributed in sequence from front to back and are connected and communicated. The liquid distribution area (101) is connected to the oil inlet pipe (2), and a liquid distributor (5) is arranged inside it. The primary electric dehydration area (102), the primary sedimentation area (103), the secondary electric dehydration area (104) and the secondary sedimentation area (105) are all connected to the drain pipe (4). And an insulating plate group and a bare plate group are respectively arranged in the primary electric dehydration area (102) and the secondary electric dehydration area (104). The insulating plate group and the bare plate group are respectively composed of a number of type-I plate bodies (6) and type-II plate bodies (7). Each of the type-I plate bodies (6) and type-II plate bodies (7) is distinguished between positive and negative poles, and the negative type-II plate body (7) is grounded. The type-I plate body (6) includes a central conductor layer (601), a semiconductor sub-outer layer (602) and an insulating outer layer (603) which are arranged in sequence from inside to outside. The central conductor layer (601) and the semiconductor sub-outer layer (602) are both enclosed in the insulating outer layer (603). A voltage conversion device (8) is arranged on one side of each of the type-I plate bodies (6) and type-II plate bodies (7). The voltage conversion devices (8) corresponding to the type-I plate bodies (6) and type-II plate bodies (7) are respectively electrically connected to an external AC power supply and a DC power supply. The oil storage area (106) is connected to the oil outlet pipe (3). The material of the central conductor layer (601) is metal. The semiconductor sub-outer layer (602) is a coating structure, which is coated on the surface of the central conductor layer and uses an anti-static semiconductor coating. The insulating outer layer (603) is epoxy resin formed by vacuum casting, or a fluorine material formed by die-casting as a whole.

2. An electric dehydration device for crude oil according to claim 1, Characterized in that the voltage conversion device (8) includes a transformer (801), a protective shell and a conductive rod (802). The transformer (801) is arranged in the protective shell. The conductive rod (802) is arranged at one end of the protective shell and passes through the protective shell to be connected to the output end of the transformer (801). And the conductive rod (802) of the voltage conversion device (8) corresponding to the type-I plate body (6) penetrates through the insulating outer layer (603) to be connected to the central conductor layer (601). An external wiring cable penetrates through the other end of the protective shell to be connected to the transformer (801).

3. An electric dehydration device for crude oil according to claim 2, Characterized in that a voltage monitoring module is further arranged at the output end of the transformer (801), and the voltage monitoring module has a voltage feedback circuit.

4. An electric dehydration device for crude oil according to claim 2, Characterized in that The protective housing includes a sleeve body (803), a positioning end cover (804), and a wiring end cover (805). The positioning end cover (804) and the wiring end cover (805) are respectively arranged at the front and rear ends of the sleeve body (803). The sleeve body (803) corresponding to the first-type plate body (6) is made of the same material as the outer insulating layer (603) and is integrally formed with the outer insulating layer (603) by casting or die-casting. A card slot (804a) opposite to the conductive rod (802) is formed on the positioning end cover (804), and it is clamped to the first-type plate body (6) and the second-type plate body (7) through the card slot (804a). A wiring hole (805a) for the external wiring cable to pass through is formed on the wiring end cover (805).

5. The crude oil electro-dehydration device according to claim 1, characterized in that, a positioning bracket (9) for fixing the insulating plate group and the bare plate group is further provided in the primary electro-dehydration area (102) and the secondary electro-dehydration area (104). The positioning bracket (9) includes a support skeleton (901), a support cover (902), a support seat (903), and a support plate (904). At least two groups of the support skeletons (901) are configured and are all connected to the processing tank body (1). The support cover (902) and the support seat (903) are respectively arranged on the opposite surfaces of two adjacent support skeletons (901). The support plates (904) are arranged at intervals between the support cover (902) and the support seat (903). The parts of the support cover (902) and the support seat (903) between two adjacent support plates (904) are used for fixing the first-type plate body (6) and the second-type plate body (7).

6. The crude oil electro-dehydration device according to claim 5, characterized in that, a plurality of opposite top sliding grooves (902a) and bottom sliding grooves (903a) are respectively formed on the support cover (902) and the support seat (903). One ends of the top sliding grooves (902a) and the bottom sliding grooves (903a) are closed, and the other ends are respectively communicated with the side walls of the support cover (902) and the support seat (903). The upper and lower ends of the first-type plate body (6) and the second-type plate body (7) are respectively slidably connected in the top sliding grooves (902a) and the bottom sliding grooves (903a).

7. The crude oil electro-dehydration device according to claim 1, characterized in that, at least one sampling port opposite to and communicated with the primary sedimentation area (103) and the secondary sedimentation area (105) is formed on the processing tank body (1). Each sampling port is distributed at different heights. Each sampling port is connected to a sampling drain pipe (10), and a sampling valve (11) is connected to the sampling drain pipe (10).

8. The crude oil electro-dehydration device according to claim 1, characterized in that, a monitoring component is further provided in the processing tank body (1). The monitoring component includes a liquid level gauge (12) arranged in the liquid distribution area (101) and the oil storage area (106), and a moisture content monitor (13) arranged at the oil outlet of the secondary sedimentation area (105).

9. An electro-dehydration method using the electro-dehydration equipment described in any one of claims 1-8, characterized in that, it comprises the following steps: S1: The emulsified crude oil extracted is discharged into the liquid distribution area (101) of the treatment tank body (1) through the inlet oil pipe (2), and after the flow rate of the emulsified crude oil is stabilized by the liquid distributor (5), it is discharged into the primary electro-dehydration area (102); S2: In the primary electro-dehydration area (102), the low-voltage electricity provided by the external AC power supply is transmitted to the voltage conversion device (8) corresponding to each type-I plate body (6) of the insulated plate group through the external connection cable, and is converted into high-voltage electricity by the voltage conversion device (8) and applied to the central conductor layer (601) of the type-I plate body (6). A stable AC electric field is generated between the mutually insulated type-I plate bodies (6) to perform primary electro-dehydration on the emulsified crude oil in the way of oscillating coalescence. After completion, the coalesced water is discharged through the drain pipe (4), and the crude oil overflows to the primary sedimentation area (103); S3: The emulsified crude oil with reduced water content undergoes primary gravity sedimentation dehydration in the primary sedimentation area (103). After completion, the coalesced water is discharged through the drain pipe (4), and the crude oil overflows to the secondary electro-dehydration area (104) for secondary electro-dehydration; S4: In the secondary electro-dehydration area (104), the low-voltage electricity provided by the external DC power supply is transmitted to the voltage conversion device (8) corresponding to each type-II plate body (7) of the bare plate group through the external connection cable, and is converted into high-voltage electricity by the voltage conversion device (8) and applied to the central conductor layer (601) of the type-II plate body (7). A DC electric field is generated between the type-II plate bodies (7) to perform secondary electro-dehydration on the emulsified crude oil in the way of electrophoresis coalescence. After completion, the coalesced water is discharged through the drain pipe (4), and the crude oil overflows to the secondary sedimentation area (105); S5: The emulsified crude oil with further reduced water content after secondary electro-dehydration undergoes secondary gravity sedimentation dehydration in the secondary sedimentation area (105). After completion, high-purity commercial oil is obtained, the coalesced water is discharged through the drain pipe, and the crude oil overflows to the oil storage area (106) for storage.

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