Crude oil deep electro-desalting equipment

Abstract

The utility model provides crude oil deep electro-desalting equipment which comprises an electro-desalting tank, the electro-desalting tank is horizontally arranged, a mixer and a drainage pipeline are respectively arranged at the bottom of the electro-desalting tank, an electrode plate is arranged at the upper position in the electro-desalting tank, a dilution water distributor is arranged above the electrode plate, and the dilution water distributor is connected with a dilution water inlet pipeline. A crude oil outlet pipeline is arranged at the top of the electric desalting tank, one end of the mixer is connected with the electric desalting tank, the other end of the mixer is connected with a crude oil inlet pipeline and a demulsifier inlet pipeline, and a mixing valve is further arranged on the mixer. According to the utility model, fresh water is injected into the top of the vertical polar plate by adopting a countercurrent dilution water injection mode, and forms countercurrent motion with purified crude oil which just leaves a strong electric field and is removed. The injection of the countercurrent dilution water makes the most fresh salt-free water contact with the cleanest crude oil, so that the utilization rate of the dilution water is highest. An electric desalting tank with a smaller size and fewer electric desalting stages can be used, and the salt content after desalting is stably smaller than a specified value or even lower.

Description

Technical Field

[0001] The utility model relates to the technical field of petroleum processing, in particular to a crude oil deep electric desalting device. Background Art

[0002] Crude oil atmospheric and vacuum distillation is the first process of crude oil processing in refineries, and electric desalting and dehydration is the first link of atmospheric and vacuum distillation. With the increasing maturity of crude oil desalting, dehydration and demetallization technology, crude oil electric desalting is no longer just a simple anti-corrosion method, but has developed into an essential crude oil pretreatment process for downstream devices to provide high-quality raw materials. It is an important process for refineries to reduce energy consumption, reduce equipment scaling and corrosion, prevent catalyst poisoning, reduce catalyst consumption and improve product quality. With the development of secondary processing technology, heavy oil catalytic cracking and hydrogenation technology in recent years, higher requirements have been put forward for the salt content of crude oil after desalting. If the purpose is to prevent corrosion, the salt content and water content of crude oil after electric desalting must be less than a certain value; if it is to protect the catalyst in the secondary processing process, deep desalting is required, and the salt content of crude oil after electric desalting is more stringent. Therefore, the electric desalting process is not only a very important first step in oil refining, but also the operation effect of the electric desalting device directly affects the subsequent processing equipment. Electric desalting technology is increasingly valued by people.

[0003] Crude oil electric desalting means that crude oil passes through an electric desalting device, and under the action of electric field, demulsifier, water injection and mixing, oil and water separation is achieved, thereby removing salt, water, metal ions, impurities, etc. from the crude oil. The electric desalting method is a desalting and dehydrating method that combines heat, chemistry and electric field.

[0004] Normally, crude oil electrical desalting adopts a two-stage or three-stage desalting and dehydrating process. In order to ensure good crude oil desalting and dehydrating indicators and meet the needs of subsequent processing equipment, it is also necessary to optimize the process conditions that affect the crude oil electrical desalting effect, including the type and injection amount of demulsifier, desalting temperature, oil-water mixing intensity, injection amount of washing water, electric field intensity and crude oil residence time, etc. The traditional method of first injecting water, injecting demulsifiers and then performing electric field agglomeration dehydration is difficult to achieve the indicator that the salt content of crude oil after electrical desalting is less than a certain value.

[0005] The current crude oil electric desalting technology and equipment need to design larger electric desalting tanks and more electric desalting stages to meet the above requirements. Utility Model Content

[0006] In order to solve the problem that the salt content in the oil phase is less than a certain value after the traditional equipment in the above-mentioned prior art is difficult to achieve electrical desalination of crude oil.

[0007] The utility model proposes a crude oil deep electric desalination device. The utility model is realized through the following technical solutions:

[0008] The electric desalter comprises an electric desalter, which is arranged horizontally. A mixer and a drainage pipe are arranged at the bottom of the electric desalter respectively. An electrode plate is arranged at the upper position inside the electric desalter, a dilution water distributor is arranged above the electrode plate, the dilution water distributor is connected to the dilution water inlet pipe, a crude oil outlet pipe is arranged on the top of the electric desalter, one end of the mixer is connected to the electric desalter, and the other end is connected to the crude oil inlet pipe and the demulsifier inlet pipe, and a mixing valve is also arranged on the mixer.

[0009] Furthermore, the electrode plates are vertically suspended mesh plates, which are arranged in sequence along the length direction of the electric desalination tank.

[0010] Furthermore, the distance between each electrode plate is 10 to 30 cm.

[0011] Furthermore, the distance between the dilution water distributor and the upper edge of the electrode plate is 10 to 20 cm.

[0012] Furthermore, a transformer is arranged on the top of the electric desalination tank, a dilution water regulating valve is arranged on the dilution water inlet pipeline, and the dilution water regulating valve is interlocked with the operating current of the transformer.

[0013] Furthermore, an oil-water interface meter is arranged on the top of the electric desalting tank, a drainage regulating valve is arranged on the drainage pipeline, and the drainage regulating valve is interlocked with the oil-water interface meter.

[0014] Furthermore, the dilution water distributor is a branched tubular structure. After the dilution water inlet pipe enters the electric desalination tank, it is divided into a number of dilution water distribution branches arranged in sequence. Each dilution water distribution branch is provided with a dilution water nozzle, and the dilution water distribution branches are arranged at intervals from the electrode plates.

[0015] Furthermore, the equipment also includes a programmable control system (PLC), and the mixing valve, transformer, dilution water regulating valve, oil-water interface meter and drainage regulating valve are all connected to the PLC.

[0016] Compared with the prior art, the beneficial effects of the utility model are:

[0017] The countercurrent dilution water injection method is adopted to inject fresh water on the top of the vertical plate, forming a countercurrent movement with the clean crude oil after desalting that has just left the strong electric field. The injection of countercurrent dilution water allows the freshest salt-free water to contact the cleanest crude oil (after being treated by the electric field), so that the utilization rate of the dilution water is the highest. Smaller electric desalting tanks and fewer electric desalting stages can be used to stably achieve a salt content after desalting that is less than the specified value or even lower, meeting the demand for ultra-low salt content in deep processing of crude oil.

[0018] Advantages and features of the present invention will be illustrated and explained by the following non-limiting description of preferred embodiments, which are given as examples only with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the overall structure of the utility model.

[0020] Figure 2 This is a partial enlarged view of the dilution water distributor structure of the utility model.

[0021] Indicated in the figure:

[0022] 1. Crude oil inlet pipeline; 2. Demulsifier inlet pipeline; 3. Mixer; 4. Mixing valve; 5. Electric desalter; 6. Electrode plate; 7. Dilution water distributor; 8. Transformer; 9. Dilution water inlet pipeline; 10. Dilution water regulating valve; 11. Crude oil outlet pipeline; 12. Oil-water interface meter; 13. Drainage pipeline; 14. Drainage regulating valve; 701. Dilution water distribution branch pipe; 702. Dilution water nozzle. DETAILED DESCRIPTION

[0023] The present application is further described below in conjunction with the accompanying drawings and embodiments.

[0024] like Figure 1 and Figure 2As shown, the utility model provides a crude oil deep electric desalting device, including an electric desalting tank 5, the electric desalting tank 5 is horizontally arranged, a mixer 3 and a drainage pipe 13 are respectively arranged at the bottom of the electric desalting tank 5, an electrode plate 6 is arranged at the upper position inside the electric desalting tank 5, a dilution water distributor 7 is arranged above the electrode plate 6, and the dilution water distributor 7 is connected to the dilution water inlet pipe 9 for injecting dilution water. A crude oil outlet pipe 11 is arranged on the top of the electric desalting tank 5. One end of the mixer 3 is connected to the electric desalting tank 5, and the other end is connected to the crude oil inlet pipe 1 and the demulsifier inlet pipe 2. A mixing valve 4 is also arranged on the mixer 3. Crude oil enters the device from the crude oil inlet pipe 1, and the demulsifier enters the device from the demulsifier inlet pipe 2. The crude oil and the demulsifier are fully mixed through the mixer 3 and the mixing valve 4, and the demulsifier demulsifies the crude oil emulsion, and the demulsified crude oil enters the electric desalting tank 5. An electrode plate 6 is arranged at the upper part of the electric desalter 5. The electrode plate 6 is a series of vertically suspended mesh, plate or grid plates, which are arranged in sequence along the length direction of the electric desalter 5. The spacing between each electrode plate 6 is 10 to 30 cm, or the spacing between the electrode plates 6 is determined according to the specific voltage and crude oil properties. A dilution water distributor 7 is arranged in the electric desalter 5. The dilution water distributor 7 is arranged just above the electrode plate 6, and maintains a spacing of 10 to 20 cm with the upper edge of the electrode plate 6, or the distance between the dilution water distributor 7 and the electrode plate 6 is determined according to the specific size and insulation requirements of the electric desalter 5. A transformer 8 is arranged at the top of the electric desalter 5. The dilution water enters the dilution water distributor 7 inside the electric desalter 5 from the dilution water inlet pipe 9. After being distributed by the dilution water distributor 7, the dilution water droplets are evenly sprayed between the electrode plates 6. A crude oil outlet pipe 11 is arranged at the top of the electric desalter 5. The crude oil after electrolysis leaves the electric desalter 5 from the crude oil outlet pipe 11 and goes to the subsequent processing flow. An oil-water interface level meter 12 is also provided on the top of the electric desalter 5, and the oil-water interface level meter 12 indicates the interface between the oil phase and the water phase inside the electric desalter 5. A drainage pipe 13 is provided at the bottom of the electric desalter 5, and a drainage regulating valve 14 is provided on the drainage pipe 13. The drainage regulating valve 14 is interlocked with the oil-water interface level meter 12, and the oil-water interface level in the electric desalter 5 is adjusted according to the opening or closing of the drainage regulating valve 14. When the oil-water interface level indicated by the oil-water interface level meter 12 is lower than the set value, the drainage regulating valve 14 is closed to reduce the drainage volume. When the oil-water interface level indicated by the oil-water interface level meter 12 is higher than the set value, the drainage regulating valve 14 is opened to increase the drainage volume. A dilution water regulating valve 10 is provided on the dilution water inlet pipe 9. The dilution water regulating valve 10 is interlocked with the operating current of the transformer 8. When the operating current of the transformer 8 is higher than the set value, the dilution water regulating valve 10 is closed to reduce the injection amount of dilution water. When the operating current of the transformer 8 is lower than the set value, the dilution water regulating valve 10 is opened to increase the injection amount of dilution water.

[0025] In the device, the movement path of the oil phase is as follows: the oil phase and the demulsifier are mixed in the crude oil inlet pipeline 1, through the mixer 3 and the mixing valve 4, and enter the bottom of the electric desalter 5, and move upward from the bottom of the electric desalter 5. When the oil phase moves to the electrode plate 6 area, the small amount of water carried in the oil phase aggregates and settles under the action of the strong electric field between the electrode plates 6. The oil phase continues to move upward, leaves the electrode plate 6 area, contacts with the dilution water from the dilution water distributor 7, is washed by the dilution water, and the salts are dissolved in the dilution water. The oil phase continues to move upward and leaves the electric desalter 5 from the crude oil outlet pipeline 11, realizing deep dehydration and desalination.

[0026] The movement path of the water phase is as follows: the dilution water enters the dilution water distributor 7 in the electric desalter 5 from the dilution water inlet pipe 9, is distributed to the crude oil in the electric desalter 5 through the dilution water distributor 7, washes and desalts the crude oil, and then settles downward, passes through the electrode plate 6 area, washes and desalts the crude oil again in the strong electric field formed by the electrode plate 6, and then continues to settle downward to form a water layer at the bottom of the electric desalter 5. The water in the water layer leaves the electric desalter 5 from the drainage pipe 13, carrying out the dissolved salts.

[0027] Preferably, the dilution water distributor 7 is a branched tubular structure. After the dilution water inlet pipe 9 enters the electric desalting tank 5, it is divided into a plurality of dilution water distribution branches 701 arranged in sequence, and each dilution water distribution branch 701 is provided with a dilution water nozzle 702. The dilution water distribution branch 701 is arranged at intervals from the electrode plate 6. The arrangement of the dilution water distribution branch 701 is mainly to consider arranging the dilution water distribution branch 701 between the two electrodes, so that the water sprayed by the dilution water nozzle 702 can be better distributed between the two electrode plates 6, so as to achieve deep washing of the crude oil.

[0028] A programmable control system (PLC) is also installed in the equipment. All instrument signals, regulating valves, and oil-water interface status are transmitted to the PLC. Various logic control programs are compiled in the PLC to realize control of the entire system.

[0029] In addition to the above embodiments, the present application may also have other implementation modes. Any technical solutions formed by equivalent replacement or equivalent transformation shall fall within the protection scope required by the present application.

Claims

1. A crude oil deep electric desalting device, comprising an electric desalting tank (5), the electric desalting tank (5) being arranged horizontally, characterized in that: A mixer (3) and a drainage pipe (13) are respectively arranged at the bottom of the electric desalter (5); an electrode plate (6) is arranged at an upper position inside the electric desalter (5); a dilution water distributor (7) is arranged above the electrode plate (6); the dilution water distributor (7) is connected to a dilution water inlet pipe (9); a crude oil outlet pipe (11) is arranged at the top of the electric desalter (5); one end of the mixer (3) is connected to the electric desalter (5); and the other end is connected to a crude oil inlet pipe (1) and a demulsifier inlet pipe (2); and a mixing valve (4) is also arranged on the mixer (3).

2. A crude oil deep electric desalting device according to claim 1, characterized in that: The electrode plates (6) are vertically suspended mesh plates, which are arranged in sequence along the length direction of the electric desalination tank (5).

3. The crude oil deep electric desalination equipment according to claim 2, characterized in that: The distance between each electrode plate (6) is 10 to 30 cm.

4. The crude oil deep electric desalting equipment according to claim 1, characterized in that: The distance between the dilution water distributor (7) and the upper edge of the electrode plate (6) is 10 to 20 cm.

5. The crude oil deep electric desalting equipment according to claim 1, characterized in that: A transformer (8) is arranged on the top of the electric desalination tank (5), a dilution water regulating valve (10) is arranged on the dilution water inlet pipeline (9), and the dilution water regulating valve (10) is interlocked with the operating current of the transformer (8).

6. The crude oil deep electric desalination equipment according to claim 1, characterized in that: An oil-water interface meter (12) is also arranged on the top of the electric desalting tank (5), and a drainage regulating valve (14) is arranged on the drainage pipeline (13), and the drainage regulating valve (14) is interlocked with the oil-water interface meter (12).

7. The crude oil deep electric desalting equipment according to claim 1, characterized in that: The dilution water distributor (7) is a branched tubular structure. After the dilution water inlet pipe (9) enters the electric desalination tank (5), it is divided into a plurality of dilution water distribution branches (701) arranged in sequence. Each dilution water distribution branch (701) is provided with a dilution water nozzle (702). The dilution water distribution branch (701) is arranged at intervals from the electrode plate (6).

8. The crude oil deep electric desalting equipment according to claim 1, characterized in that: The equipment also includes a programmable control system (PLC), and the mixing valve (4), transformer (8), dilution water regulating valve (10), oil-water level meter (12) and drainage regulating valve (14) are all connected to the PLC.

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