Primary tower side line improvement device for petrochemical atmospheric and vacuum separation device

Abstract

The utility model relates to a primary tower side line improvement device for a petrochemical atmospheric and vacuum separation device. The primary tower side line improvement device comprises a primary tower and an atmospheric tower which are arranged at an interval, a removed crude oil inlet end is arranged at one end of the primary tower; the bottom of the primary tower is connected with a normal-pressure furnace through a primary bottom oil pipeline, and one side of the normal-pressure furnace is communicated with the normal-pressure tower through a normal-pressure feeding pipe; one side of the atmospheric tower is sequentially provided with a normal top backflow, a normal top circulation, a normal first neutralization and a normal second neutralization from top to bottom; a normal first-line product, a normal second-line product, a normal third-line product and a normal fourth-line product are sequentially arranged on the other side of the normal-pressure tower from top to bottom; a normal first-line reboiler is further arranged on one side of the normal first-line product; the middle part of one side of the primary distillation tower is communicated with a primary side product stripping tower through a primary side oil pipeline; and the final boiling point of the primary side oil is lower than that of a normal first-line product. According to the primary tower side line improvement device for the petrochemical atmospheric and vacuum separation device, the energy-saving effect is kept, the heat loss of the device is effectively reduced, and the load of a heating furnace is relieved; the normal working state in the tower is maintained; and the quality of a normal product is guaranteed.

Description

Technical Field

[0001] The utility model relates to the technical field of oil refining devices, in particular to a primary distillation tower side line improvement device used in a petrochemical atmospheric and vacuum separation device. Background Art

[0002] The oil refining industry is characterized by complex equipment, multiple production processes, and long operation cycles, and it also consumes a lot of energy. As the leading equipment in the entire oil refining industry, the atmospheric and vacuum unit consumes a lot of energy. Among them, the fuel consumption of the heating furnace accounts for about half of the total consumption of the atmospheric and vacuum unit. In the context of advocating energy conservation and emission reduction today, there is great potential for optimizing it with the goal of reducing energy consumption.

[0003] With the continuous development of refineries, it is often necessary to expand the scale of processing equipment. In addition, with the increasing diversification of crude oil types, how to reduce process energy consumption while taking into account product quality and processing volume has become an issue worthy of study.

[0004] The classic atmospheric and vacuum process design generally consists of crude oil heat exchange, primary distillation, atmospheric pressure, vacuum, light hydrocarbon recovery and one decompression and three injections. The crude oil is heated to a suitable temperature after heat exchange and enters the fractionation system, where it is separated into different fractions through distillation, and then cooled and sent out through heat exchange.

[0005] Due to the different influences of factors such as the processing capacity of each device and the properties of crude oil, it is necessary to arrange the atmospheric and vacuum equipment and its process in accordance with the actual situation. Therefore, various variant atmospheric and vacuum process designs based on the classical process have been derived. Among them, the atmospheric and vacuum process design with the primary side line is different from the classical process in that part of the light oil in the primary bottom oil that was originally heated in the atmospheric furnace and then entered the atmospheric tower is extracted from the primary distillation tower in the form of a primary side line and directly enters the upper part of the atmospheric tower as reflux.

[0006] The commissioning of the primary side line can bring the following benefits to the device: On the one hand, the primary side oil does not pass through the heating furnace but directly enters the atmospheric pressure tower, which can avoid the heat loss caused by repeated heating, vaporization and condensation of this component, reduce the load of the heating furnace and reduce the energy consumption of the device. On the other hand, when an existing device faces the demand for increased production, without the preparation of large-scale equipment replacement, the operating bottleneck is often seen in the heating furnace. The design of the primary side line can increase the processing capacity of the device without causing a large amount of equipment investment, and the implementation difficulty is relatively low.

[0007] However, while this measure saves energy, it will also have an adverse effect on the operation of the subsequent atmospheric tower. The properties of the primary oil are related to the properties of the crude oil, the operating status of the primary distillation tower, the amount of primary oil extracted, etc. It is difficult to keep it stable at all times. Injecting it into the atmospheric tower will affect the original gas-liquid phase distribution in the tower, disrupt the stable operating status, and fluctuate product quality.

[0008] At present, the contradiction between energy saving of heating furnace and stable operation of atmospheric pressure tower has not been effectively solved. Summary of the invention

[0009] The technical problem to be solved by the utility model is: in order to solve the problems existing in the above-mentioned background technology, a side line improvement device for a primary distillation tower of a petrochemical atmospheric and vacuum separation device is provided, which takes into account both energy saving of a heating furnace and normal operation of an atmospheric tower; it does not pass through the atmospheric furnace, so the energy saving effect of the existing design can be continued, the heat loss of the device is effectively reduced, and the load of the heating furnace is alleviated; it does not directly enter the atmospheric tower, so the influence of the existing design on the internal operation of the atmospheric tower can be eliminated, and the normal working state in the tower is maintained; and under the condition of controlling the primary side oil extraction flow rate and the reboiling load of the product tower, the newly designed primary side line entering the atmospheric pressure stripping tower will not cause adverse effects on the quality of the atmospheric pressure product.

[0010] The utility model solves the technical problem by adopting the following technical scheme: a primary distillation tower side line improvement device for a petrochemical atmospheric and vacuum separation device, comprising a primary distillation tower and an atmospheric tower arranged at intervals; a stripped crude oil inlet end is arranged at one end of the primary distillation tower; the bottom of the primary distillation tower is connected to an atmospheric furnace through a primary bottom oil pipeline, and one side of the atmospheric furnace is connected to the atmospheric tower through an atmospheric feed pipe; one side of the atmospheric tower is provided with atmospheric top reflux, atmospheric top circulation, atmospheric first intermediate and atmospheric second intermediate in sequence from top to bottom; the other side of the atmospheric tower is provided with atmospheric first line products, atmospheric second line products, atmospheric third line products and atmospheric fourth line products in sequence from top to bottom; a atmospheric first line reboiler is also arranged at one side of the atmospheric first line products; the middle part of one side of the primary distillation tower is connected to an atmospheric first line product stripping tower through a primary side oil pipeline; the final distillation point of the primary side oil is lower than the final distillation point of the atmospheric first line products.

[0011] It is further defined that, in the above technical solution, the final distillation point of the primary side oil is lower than the final distillation point of the normal first-line product.

[0012] It is further defined that, in the above technical solution, the primary side oil production ratio accounts for 0%-5% of the feed amount of the primary distillation tower.

[0013] It is further defined that in the above technical solution, the normal line reboiler provides heat to the normal line product stripping tower to heat the normal line product to be fractionated and the input primary side oil.

[0014] The beneficial effects of the utility model are as follows: the utility model proposes an improved device for the side line of the primary distillation tower of a petrochemical atmospheric and vacuum separation device, which takes into account both the energy saving of the heating furnace and the normal operation of the atmospheric tower; it does not pass through the atmospheric furnace, thus continuing the energy saving effect of the existing design, effectively reducing the heat loss of the device and alleviating the load of the heating furnace; it does not directly enter the atmospheric tower, thus eliminating the influence of the existing design on the internal operation of the atmospheric tower and maintaining the normal working state in the tower; and under the condition of controlling the primary side oil extraction flow rate and the reboiling load of the product tower, the newly designed primary side line entering the atmospheric pressure stripping tower will not have an adverse effect on the quality of the atmospheric pressure product. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 It is a traditional classic atmospheric and vacuum process design flow chart;

[0017] Figure 2 This is the design flow chart of the existing atmospheric and vacuum process including the primary side line;

[0018] Figure 3 It is a process flow chart of the utility model.

[0019] The numbers in the accompanying drawings are: 1, de-stripped crude oil, 2, primary distillation tower, 3, primary top naphtha, 4, primary top reflux, 5, primary bottom oil, 6, atmospheric furnace, 7, atmospheric feed pipe, 8, atmospheric tower, 9, atmospheric top naphtha, 10, atmospheric top reflux, 11, atmospheric top circulation, 12, atmospheric first middle, 13, atmospheric second middle, 14, atmospheric bottom steam injection, 15, atmospheric first line reboiler, 16, atmospheric first line product, 17, atmospheric second stripping steam, 18, atmospheric second line product, 19, atmospheric third stripping steam, 20, atmospheric third line product, 21, atmospheric fourth line product, 22, atmospheric bottom oil, 23, primary side oil. DETAILED DESCRIPTION

[0020] In order to make the technical problems, technical solutions and beneficial effects solved by the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0021] In the present application, the initial top naphtha 3 and the initial top reflux 4: the crude oil after desalting and dehydration enters the primary distillation tower, and the fraction distilled from the top of the tower is condensed and cooled, and a part of it is used as the top reflux, and the other part is drawn out as the initial top naphtha. The initial bottom oil 5: the heavy component oil extracted from the bottom of the tower is called "initial bottom oil". Atmospheric pressure furnace 6: the initial bottom oil 5 enters the atmospheric pressure furnace 6 for further heating. Atmospheric pressure tower 8: the initial bottom oil 5 enters the atmospheric pressure tower 8 for separation after heating, and the lighter naphtha component can be separated from the top of the tower, and the heavy oil product is produced at the bottom of the tower, and the diesel or wax oil component between the two is produced by the side line. Regular first-line product 16, regular second-line product 18, regular third-line product 20 and regular fourth-line product 21: the first line of the side line of the atmospheric pressure tower 8 is called the regular first-line product 16, and so on, the second line is called the regular second-line product 18, the third line is called the regular third-line product 20, and the fourth line is called the regular fourth-line product 21. Normal top circulation 11, normal first middle 12 and normal second middle 13: the atmospheric tower 8 is provided with three middle section refluxes. According to the height of the stream extraction position, from the top of the tower to the bottom, the distribution order is normal top circulation 11, normal first middle 12 and normal second middle 13. Normal second stripping steam 17, normal third stripping steam 19: the steam used for stripping is usually also called stripping steam. Its main function is to reduce the oil and gas partial pressure in the tower. The purpose of the side product stripping is to vaporize the light components in the product to ensure the quality of the side product. Normal first line reboiler 15: similar to the side product steam stripping, the light components can also be extracted by reboiling. The temperature in the tower is increased by the reboiler, and the light components mixed in the normal first product are vaporized and returned to the atmospheric tower to ensure that the product quality and yield meet the production requirements. The normal first line reboiler vaporizes the normal first product and the light fraction in the input primary side oil, so that the light fraction enters the normal top naphtha 9, thereby meeting the minimum flash point requirements of the output normal first line product.

[0022] See Figure 1 This is a schematic diagram of the traditional design process without primary side oil. The crude oil is heated to a suitable temperature through heat exchange and enters the distillation system. Different fractions of products are separated through distillation, and then cooled and sent out through heat exchange.

[0023] See Figure 2 The schematic diagram of the design process with primary side oil is that the light oil 8 of the primary bottom oil 5, which was originally heated by the atmospheric furnace 6 and then entered the atmospheric tower, is extracted from the primary distillation tower 2 in the form of a primary side line and directly enters the upper part of the atmospheric tower 8 as reflux. This measure will not only save energy, but also have an adverse effect on the operation of the subsequent atmospheric tower. The properties of the primary side oil are related to the properties of the crude oil, the operating state of the primary distillation tower, the amount of primary side oil extracted, etc. It is difficult to keep it stable at all times. Injecting it into the atmospheric tower will affect the original gas-liquid phase distribution in the tower, disrupt the stable operating state, and fluctuate the product quality.

[0024] See Figure 3The figure shows an improved device for the side line of a primary distillation tower used in a petrochemical atmospheric and vacuum separation device, comprising a primary distillation tower 2 and an atmospheric tower 8 arranged at intervals; an inlet end of a stripped crude oil 1 is arranged at one end of the primary distillation tower 2; the bottom of the primary distillation tower 2 is connected to an atmospheric furnace 6 through a primary bottom oil 5 pipeline, and one side of the atmospheric furnace 6 is connected to an atmospheric tower 8 through an atmospheric feed pipe 7; one side of the atmospheric tower 8 is provided with a top reflux 9, a top circulation 11, a first intermediate 12 and a second intermediate 13 in sequence from top to bottom; the other side of the atmospheric tower 8 is provided with a first-line product 16, a second-line product 18, a third-line product 20 and a fourth-line product 21 in sequence from top to bottom; a first-line reboiler 15 is also provided at one side of the first-line product 16; the primary side oil 23 is produced from the middle of one side of the primary distillation tower 2 and is sent to a first-line product stripping tower, which is connected to the first-line product 16; the final distillation point of the primary side oil 23 is lower than the final distillation point of the first-line product 16.

[0025] Among them, a normal second-line product 18 is also provided with a normal second stripping steam 17. A normal third-line product 20 is also provided with a normal third stripping steam 19. A normal bottom oil 22 pipeline is provided at the bottom of the atmospheric tower 8. A normal bottom steam injection 14 is also provided at one side of the lower part of the atmospheric tower 8. The upper end of the atmospheric tower 8 is connected to the normal top naphtha 9 and the normal top reflux 10 through a pipeline. The upper end of the primary distillation tower 2 is connected to the primary top naphtha 3 and the primary top reflux 4.

[0026] Preferably, in the above technical solution, one side of the conventional second-line product is also provided with conventional second-line stripping steam.

[0027] Preferably, in the above technical solution, one side of the Chang San line product is also provided with Chang San stripping steam.

[0028] Preferably, in the above technical solution, a normal pressure oil pipeline is arranged at the bottom of the normal pressure tower.

[0029] Preferably, in the above technical solution, a normal bottom steam injection is also arranged on one side of the lower part of the atmospheric pressure tower.

[0030] Preferably, in the above technical solution, the upper end of the atmospheric pressure tower is connected to the normal top naphtha and the normal top reflux through a pipeline.

[0031] Preferably, in the above technical solution, the upper end of the primary distillation tower is connected to the initial top naphtha and the initial top reflux.

[0032] In the present application, after applying the new design containing the primary side line, the quality of the normal-pressure furnace product completely coincides with the original design and is not affected, and the quality of the normal-pressure furnace top naphtha is also basically consistent with the original state and can meet the process requirements; at the same time, the total flow rate of the normal-pressure furnace product and above remains unchanged, so that the normal-pressure furnace reboiler load is increased to ensure that the normal-pressure furnace product is not affected by the mixing of the primary side oil; and the device can continue to maintain the original energy-saving effect, and the new primary side design for extracting the primary side oil can still save the atmospheric pressure furnace load, and the saving in the atmospheric pressure furnace load is greater than the increase in the normal-pressure furnace reboiler load.

[0033] The present application proposes to open a side line in the middle of the primary distillation tower 2, and reboil the primary side oil 23 together with the normal line to produce the product. This can maintain the energy-saving load of the heating furnace, product quality and output unchanged, and at the same time, reduce the impact of the primary side oil on the atmospheric pressure tower 8 to the maximum extent by adding a part of the normal line reboiler load, thereby taking into account the win-win situation of stable operation of the device and energy saving and consumption reduction.

[0034] What is described above is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes within the technical scope disclosed by the present invention according to the technical scheme and the utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A primary distillation tower side line improvement device for a petrochemical atmospheric and vacuum separation device, comprising a primary distillation tower and an atmospheric tower arranged at intervals; one end of the primary distillation tower is provided with a crude oil inlet after degassing; the bottom of the primary distillation tower is connected to an atmospheric furnace through a primary bottom oil pipeline, and one side of the atmospheric furnace is connected to the atmospheric tower through an atmospheric feed pipe; one side of the atmospheric tower is provided with a top reflux, a top circulation, a first intermediate and a second intermediate in sequence from top to bottom; the other side of the atmospheric tower is provided with a first-line product, a second-line product, a third-line product and a fourth-line product in sequence from top to bottom; a first-line reboiler is also provided on one side of the first-line product; it is characterized in that: The middle part of one side of the primary distillation tower is connected to the normal first-line product stripping tower through a primary side oil pipeline; the normal first-line reboiler is connected to the normal first-line product stripping tower.

2. The side line improvement device for a primary distillation tower of a petrochemical atmospheric and vacuum separation device according to claim 1, characterized in that: The final distillation point of the primary side oil is lower than the final distillation point of the normal first-line product.

3. The side line improvement device for the primary distillation tower of a petrochemical atmospheric and vacuum separation device according to claim 1, characterized in that: The primary side oil production ratio accounts for 0%-5% of the primary distillation tower feed volume.

4. The side line improvement device for a primary distillation tower of a petrochemical atmospheric and vacuum separation device according to claim 1, characterized in that: The normal first-line reboiler provides heat to the normal first-line product stripping tower to heat the normal first-line product to be fractionated and the input primary side oil.

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