Crude oil electric desalting device

Abstract

The utility model relates to the technical field of crude oil processing, in particular to a crude oil electric desalting device which comprises a primary electric desalting tank, a first-stage electric desalting tank, a second-stage electric desalting tank, a third-stage electric desalting tank, a material conveying header pipe and a crossover line. According to the utility model, on-line switching between series connection and parallel connection of the first-stage electric desalting tank and the second-stage electric desalting tank can be realized, and when the processing amount is low, the first-stage electric desalting tank and the second-stage electric desalting tank can be operated in series, so that the indexes of dehydration and desalting of crude oil can be met; when the treatment capacity is increased, the flow rate of crude oil is increased, and the retention time of the crude oil in electro-desalting is reduced, the retention time of the crude oil is prolonged by connecting the first-stage electro-desalting tank and the second-stage electro-desalting tank in parallel, and corresponding parameters such as water injection rate and electric field intensity can be respectively set according to the specific operation conditions of the first-stage electro-desalting tank and the second-stage electro-desalting tank; the operation flexibility of the electro-desalting system is improved to a certain extent, and the indexes that crude oil contains salt and water after being desalted can be achieved under the condition of high treatment capacity.

Description

Technical Field

[0001] This utility model relates to the field of crude oil processing technology, specifically to a crude oil electro-desalting device. Background Technology

[0002] Electro-desalting is a crucial pretreatment step in crude oil processing before distillation. Electro-desalting utilizes an electric field to physically remove salts and water from crude oil. Its primary purpose is to remove dissolved inorganic salts such as NaCl, MgCl2, and CaCl2. The presence of these salts can harm subsequent processing steps, such as causing equipment corrosion and affecting product quality. Therefore, electro-desalting is an indispensable step in crude oil processing.

[0003] The electric desalting tank is the core equipment in the crude oil electric desalting process. The working principle of the electric desalting tank is that under the action of a strong electric field and demulsifier, the water molecules in the crude oil gradually aggregate and are separated from the crude oil by gravity. The salts (sodium ions, magnesium ions, etc.) in the feed oil dissolve in the water and are removed from the crude oil together.

[0004] When using electric desalting tanks for desalting, multiple electric desalting tanks are generally connected in series for desalting. However, when processing high volumes of crude oil, the short residence time of crude oil in the electric desalting tank can easily lead to poor oil-water separation, resulting in technical problems such as excessive salt content and water-carrying after desalting. This is especially true when the raw material is high-sulfur, high-acid crude oil, which has a high salt content and is difficult to desalt, requiring modification of the electric desalting unit. Utility Model Content

[0005] To address the technical problem of poor electro-desalting effect under high crude oil processing capacity, this utility model provides a crude oil electro-desalting device that can realize online switching between the series and parallel processes of primary and secondary electro-desalting tanks, solving the technical problems of excessive salt content and oil carryover in crude oil after desalting.

[0006] This utility model provides a crude oil electrostatic desalting device, including a primary electrostatic desalting tank, a first-stage electrostatic desalting tank, a second-stage electrostatic desalting tank and a third-stage electrostatic desalting tank, as well as a feed main pipe and cross-line;

[0007] The inlet of the primary electric desalting tank is connected to the crude oil feeding device through the primary feed pipe, and the outlet of the primary electric desalting tank is connected to the main conveying pipe through the primary outlet pipe.

[0008] The inlet of the primary electric desalination tank is connected to the main conveying pipe through the primary feed pipe, and the outlet of the primary electric desalination tank is connected to the main conveying pipe through the primary discharge pipe.

[0009] The inlet of the secondary electric desalting tank is connected to the main conveying pipe through the secondary inlet pipe, and the outlet of the secondary electric desalting tank is connected to the main conveying pipe through the secondary outlet pipe.

[0010] The inlet of the three-stage electric desalination tank is connected to the main conveying pipe through a three-stage inlet pipe, and the outlet of the three-stage electric desalination tank is connected to the discharge pipe through a three-stage outlet pipe.

[0011] One end of the cross-line is connected to the primary discharge pipe, and the other end is connected to the main conveying pipe. The connection between the cross-line and the main conveying pipe is located between the connection between the secondary feed pipe, the secondary discharge pipe and the main conveying pipe.

[0012] The main conveying pipe is equipped with a first valve and a second valve, and the cross line is equipped with a third valve. The first valve is located between the connection between the primary feed pipe, the primary discharge pipe and the main conveying pipe, and the second valve is located between the connection between the secondary feed pipe, the cross line and the main conveying pipe.

[0013] Furthermore, a primary mixer is installed on the primary feed pipe, a primary mixer is installed on the first-stage feed pipe, a second-stage mixer is installed on the second-stage feed pipe, and a third-stage mixer is installed on the tertiary feed pipe. The function of each mixer is to thoroughly mix the crude oil, demulsifier, and purified water before introducing them into the electric desalting tank. Each mixer has an oil phase inlet, a demulsifier inlet, a purified water inlet, and an oil phase outlet.

[0014] Furthermore, a primary feed valve is provided on the primary feed pipe, a primary feed valve is provided on the first-stage feed pipe, a secondary feed valve is provided on the second-stage feed pipe, and a tertiary feed valve is provided on the tertiary feed pipe.

[0015] Furthermore, a primary discharge valve is provided on the primary discharge pipe, a primary discharge valve is provided on the first-stage discharge pipe, a secondary discharge valve is provided on the second-stage discharge pipe, and a tertiary discharge valve is provided on the tertiary discharge pipe.

[0016] Furthermore, one end of the main feed pipe is connected to the primary feed pipe via auxiliary line A, and the other end is connected to the discharge pipe via auxiliary line B. A third valve and a fourth valve are respectively installed on auxiliary lines A and B. This design allows crude oil to be desalted without the primary and tertiary electric desalting tanks when processing lower volumes, thus saving equipment costs.

[0017] Furthermore, the cross-line is a DN300 pipe.

[0018] The principle of this invention is as follows: Since electro-desalting is a time-dependent process (water droplets need sufficient time to gather and settle), extending the residence time can improve desalting efficiency, allowing for more thorough removal of salt and water from crude oil. This invention enables online switching between series and parallel operation of primary and secondary electro-desalting tanks, provided there are cross-line and valve configurations. At low processing volumes, the primary and secondary electro-desalting tanks can operate in series to meet crude oil dehydration and desalting requirements. As the processing volume increases, the crude oil flow rate increases, leading to a decrease in the residence time of crude oil in the electro-desalting tank. Increased processing volume means a larger amount of crude oil needs to be processed per unit time; therefore, the crude oil flow rate must be increased accordingly to maintain processing efficiency. However, this increased flow rate inevitably leads to a shorter residence time of crude oil in each electro-desalting tank, as the crude oil passes through the tank more quickly, leaving insufficient time for thorough desalting. To address this issue, this invention employs a parallel connection between a primary and a secondary electric desalting tank. This parallel configuration allows crude oil to undergo desalting simultaneously in two independent tanks, effectively extending the total residence time of the crude oil without reducing the throughput. Specifically, the crude oil is divided into two parts, which enter the primary and secondary electric desalting tanks respectively. In both tanks, the crude oil undergoes a desalting process before being combined for further processing, thus extending the residence time. Furthermore, parameters such as water injection volume and electric field strength can be set according to the specific operating conditions of the primary and secondary electric desalting tanks, improving the operational flexibility of the electric desalting system to a certain extent and facilitating the achievement of the desired salt and water content in the desalted crude oil under high throughput conditions.

[0019] The beneficial effects of this utility model are as follows: This utility model can realize the online switching of the series and parallel process of the primary and secondary electric desalting tanks, which can better adapt to the changes in oil properties, avoid the adverse effects of inferior crude oil on the electric desalting system, and solve the technical problems of poor oil-water separation effect caused by the short residence time of crude oil in the electric desalting tank, which leads to excessive salt content and water-carrying in the desalted crude oil. Attached Figure Description

[0020] To more clearly illustrate the technical solution of this utility model, the drawings used in the description will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present utility model.

[0022] Figure 2This is a schematic diagram of the structure of Embodiment 2 of this utility model.

[0023] In the diagram, 1-primary feed pipe, 2-primary feed valve, 3-primary mixer, 4-primary electric desalination tank, 5-primary discharge valve, 6-primary discharge pipe, 7-main feed pipe, 8-first valve, 9-first-stage feed pipe, 10-first-stage feed valve, 11-first-stage mixer, 12-first-stage discharge pipe, 13-first-stage discharge valve, 14-first-stage electric desalination tank, 15-secondary feed pipe, 16-secondary feed valve, 17-third valve 18 - Gate, 19 - Cross-line, 20 - Secondary discharge pipe, 21 - Secondary discharge valve, 22 - Secondary mixer, 23 - Secondary electric desalination tank, 24 - Tertiary feed pipe, 25 - Tertiary feed valve, 26 - Tertiary electric desalination tank, 27 - Tertiary discharge valve, 28 - Tertiary discharge pipe, 29 - Discharge pipe, 30 - Tertiary mixer, 31 - Sub-line A, 32 - Sub-line B, 33 - Third valve, 34 - Fourth valve. Detailed Implementation

[0024] To make the objectives, features, and advantages of this utility model more apparent and understandable, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings of the specific embodiments. Obviously, the embodiments described below are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this patent, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this patent.

[0025] Example 1

[0026] Combination Figure 1 This utility model provides a crude oil electrostatic desalting device, including a primary electrostatic desalting tank 4, a first-stage electrostatic desalting tank 14, a second-stage electrostatic desalting tank 23, and a third-stage electrostatic desalting tank 26. The primary electrostatic desalting tank 4 has a volume of 268.7 m³. 3 The volumes of the primary electrostatic desalination tank 14, the secondary electrostatic desalination tank 23, and the tertiary electrostatic desalination tank 26 are all 176 m³. 3 .

[0027] This utility model also includes a main conveying pipe 7 and a crossover line 18, the crossover line 18 being a DN300 pipe; the inlet of the primary electric desalting tank 4 is connected to the crude oil feeding device through the primary inlet pipe 1, and the outlet of the primary electric desalting tank 4 is connected to the main conveying pipe 7 through the primary outlet pipe 6; the inlet of the first-stage electric desalting tank 14 is connected to the main conveying pipe 7 through the first-stage inlet pipe 9, and the outlet of the first-stage electric desalting tank 14 is connected to the main conveying pipe 7 through the first-stage outlet pipe 12; the inlet of the second-stage electric desalting tank 23 is connected to the main conveying pipe 7 through the second-stage inlet pipe 15, and the outlet of the second-stage electric desalting tank 23 is connected to the main conveying pipe 7 through the second-stage outlet pipe 20; the inlet of the tertiary electric desalting tank 26 is connected to... The tertiary feed pipe 24 is connected to the main feed pipe 7, and the outlet of the tertiary electric desalination tank 26 is connected to the discharge pipe 29 through the tertiary discharge pipe 28; one end of the crossover 18 is connected to the primary discharge pipe 12, and the other end is connected to the main feed pipe 7, and the connection between the crossover 18 and the main feed pipe 7 is located between the connection between the secondary feed pipe 15, the secondary discharge pipe 20 and the main feed pipe 7; the main feed pipe 7 is equipped with a first valve 8 and a second valve 19, and the crossover 18 is equipped with a third valve 17. The first valve 8 is located between the connection between the primary feed pipe 9, the primary discharge pipe 12 and the main feed pipe 7, and the second valve 19 is located between the connection between the secondary feed pipe 15, the crossover 18 and the main feed pipe 7.

[0028] This utility model has a primary mixer 3 on the primary feed pipe 1, a primary mixer 11 on the first-stage feed pipe 9, a secondary mixer 22 on the second-stage feed pipe 15, and a tertiary mixer 30 on the third-stage feed pipe 24. Each mixer has an oil phase input end, a demulsifier input end, a purified water input end, and an oil phase output end, which can fully mix crude oil, demulsifier, and purified water before feeding them into the corresponding electrostatic desalting tank.

[0029] To control the flow of material within the pipeline, this invention provides a primary feed valve 2 on the primary feed pipe 1, a primary feed valve 10 on the first-stage feed pipe 9, a secondary feed valve 16 on the second-stage feed pipe 15, and a tertiary feed valve 25 on the tertiary feed pipe 24. A primary discharge valve 5 is provided on the primary discharge pipe 6, a primary discharge valve 13 on the first-stage discharge pipe 12, a secondary discharge valve 21 on the second-stage discharge pipe 20, and a tertiary discharge valve 27 on the tertiary discharge pipe 28.

[0030] The working process and principle of this utility model are as follows:

[0031] Under normal crude oil processing capacity, the primary electrostatic desalting tank 14 and the secondary electrostatic desalting tank 23 are used in series:

[0032] Open the primary feed valve 2, the first-stage feed valve 10, the second-stage feed valve 16, the third-stage feed valve 25, and the primary discharge valve 5, the first-stage discharge valve 13, the second-stage discharge valve 21, and the third-stage discharge valve 27, while simultaneously closing the first valve 8, the third valve 17, and the second valve 19.

[0033] Crude oil enters at the crude oil feeding device, and an oil-soluble demulsifier is injected simultaneously. After the crude oil undergoes a primary heat exchange, it is mixed with purified water in the primary mixer 3 and then enters the primary electric desalting tank 4. The desalted and dehydrated crude oil is discharged from the primary electric desalting tank 4, mixed with purified water and demulsifier in the primary mixer 11, and then enters the primary electric desalting tank 14. The desalted and dehydrated crude oil is discharged from the primary electric desalting tank 14, mixed with purified water and demulsifier in the secondary mixer 22, and then enters the secondary electric desalting tank 23. The desalted and dehydrated crude oil is discharged from the secondary electric desalting tank 23, mixed in the tertiary mixer 30, and then enters the tertiary electric desalting tank 26. The desalted and dehydrated crude oil is discharged from the tertiary electric desalting tank 26 and discharged through the discharge pipe 29 into the secondary heat exchange device.

[0034] Under conditions of high crude oil throughput and deteriorating crude oil quality, the primary electrostatic desalting tank 14 and the secondary electrostatic desalting tank 23 are used in parallel:

[0035] Open the primary feed valve 2, the first-stage feed valve 10, the second-stage feed valve 16, the third-stage feed valve 25, the primary discharge valve 5, the second-stage discharge valve 21, the third-stage discharge valve 27, the first valve 8, and the third valve 17; close the first-stage discharge valve 13 and the second valve 19.

[0036] Crude oil enters at the crude oil feeding device, and an oil-soluble demulsifier is injected simultaneously. After the crude oil undergoes one heat exchange, it is mixed with purified water in the primary mixer 3 and then enters the primary electric desalting tank 4. The desalted and dehydrated crude oil is discharged from the primary electric desalting tank 4 and splits into two paths. One path enters the primary mixer 11 and is mixed with purified water and demulsifier before entering the primary electric desalting tank 14. The other path enters the secondary mixer 22 and is mixed with purified water and demulsifier before entering the secondary electric desalting tank 23. The desalted and dehydrated crude oil in the primary electric desalting tank 14 enters the tertiary electric desalting tank 26 via the cross line 18. The desalted and dehydrated crude oil in the secondary electric desalting tank 23 is combined with the desalted and dehydrated crude oil in the primary electric desalting tank 14 and then enters the tertiary electric desalting tank 26, realizing the parallel use of the primary electric desalting tank 14 and the secondary electric desalting tank 23.

[0037] Example 2

[0038] Unlike Example 1, in Example 2, one end of the main feed pipe 7 is connected to the primary feed pipe 1 via a secondary line A 31, and the other end is connected to the discharge pipe 29 via a secondary line B 32. A third valve 33 and a fourth valve 34 are respectively installed on secondary lines A 31 and B 32. The purpose is to allow crude oil to be processed without using the primary electric desalting tank 4 (with the primary feed valve 2 and primary discharge valve 5 closed) and the tertiary electric desalting tank 26 (with the tertiary feed valve 25 and tertiary discharge valve 27 closed) when the throughput is low, thus saving equipment costs.

[0039] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A crude oil electro-desalter apparatus comprising a primary electro-desalter tank, a first stage electro-desalter tank, a second stage electro-desalter tank, and a third stage electro-desalter tank, characterized in that, The cross line is connected to the first-stage discharge pipe at one end and to the feed main at the other end, and the connection of the cross line to the feed main is located between the connection of the second-stage feed pipe and the second-stage discharge pipe to the feed main. The feed inlet of the primary electric desalting tank is connected to the crude oil supply device through a primary feed pipe, and the discharge outlet of the primary electric desalting tank is connected to the feed main through a primary discharge pipe. The feed inlet of the first-stage electric desalting tank is connected to the feed main through a first-stage feed pipe, and the discharge outlet of the first-stage electric desalting tank is connected to the feed main through a first-stage discharge pipe. The feed inlet of the second-stage electric desalting tank is connected to the feed main through a second-stage feed pipe, and the discharge outlet of the second-stage electric desalting tank is connected to the feed main through a second-stage discharge pipe. The feed inlet of the third-stage electric desalting tank is connected to the feed main through a third-stage feed pipe, and the discharge outlet of the third-stage electric desalting tank is connected to the discharge pipe through a third-stage discharge pipe. The cross line is connected to the first-stage discharge pipe at one end and to the feed main at the other end, and the connection of the cross line to the feed main is located between the connection of the second-stage feed pipe and the second-stage discharge pipe to the feed main. The feed main is provided with a first valve and a second valve, and the cross line is provided with a third valve, the first valve being located between the connection of the first-stage feed pipe and the first-stage discharge pipe to the feed main, and the second valve being located between the connection of the second-stage feed pipe and the cross line to the feed main.

2. The electric desalter for crude oil as claimed in claim 1, wherein, The primary feed pipe is provided with a primary mixer, the first-stage feed pipe is provided with a first-stage mixer, the second-stage feed pipe is provided with a second-stage mixer, and the third-stage feed pipe is provided with a third-stage mixer.

3. The electric desalter for crude oil as claimed in claim 1, wherein, The primary feed pipe is provided with a primary feed valve, the first-stage feed pipe is provided with a first-stage feed valve, the second-stage feed pipe is provided with a second-stage feed valve, and the third-stage feed pipe is provided with a third-stage feed valve.

4. The electric desalter for crude oil as claimed in claim 1, wherein, The primary discharge pipe is provided with a primary discharge valve, the first-stage discharge pipe is provided with a first-stage discharge valve, the second-stage discharge pipe is provided with a second-stage discharge valve, and the third-stage discharge pipe is provided with a third-stage discharge valve.

5. The electric desalter for crude oil as claimed in claim 1, wherein, The feed main is connected to the primary feed pipe through a secondary line A at one end and to the discharge pipe through a secondary line B at the other end, and the secondary line A and the secondary line B are respectively provided with a third valve and a fourth valve.

6. The electric desalter for crude oil according to any one of claims 1 to 5, characterized by, The cross line is a DN300 pipe.

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