Stable tower bottom fractionation system of aromatization device and method for extracting heavy aromatic oil
By employing a stable bottom fractionation system in the aromatization unit and utilizing a vertical reboiler and steam box design, effective separation of light and heavy aromatics is achieved, solving the problems of heavy aromatics affecting the extraction of light aromatics and high energy consumption, thus achieving energy saving and consumption reduction.
Patent Information
- Application Number
- CN202410408662.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-07
- Publication Date
- 2025-10-17
AI Technical Summary
In the aromatization unit, the mixing of heavy aromatics with light aromatics affects the extraction of light aromatics, leading to a decrease in the quality of light aromatic gasoline, and increasing the energy consumption of the light aromatic fractionation tower, thus raising production costs.
A stable bottom fractionation system is adopted, utilizing a vertical reboiler and steam box design. Through the separation principle of heat exchange chamber and separation chamber, and taking advantage of the difference in boiling points of light and heavy aromatics, the effective separation of light and heavy aromatics is achieved, reducing the heat source supply for subsequent light aromatic fractionation towers.
It achieves efficient separation of light and heavy aromatics, reduces energy consumption of light aromatics distillation towers, lowers production costs, and improves the quality of light aromatics oil.
Smart Images
Figure CN120795945A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of aromatization production, and in particular to a stable column bottom fractionation system of an aromatization device and a method for extracting heavy aromatic oil. BACKGROUND
[0002] A small amount of heavy aromatic hydrocarbon is produced in the production process of the aromatization device. Mixing the heavy aromatic hydrocarbon into light aromatic hydrocarbon can affect the dry point of the light aromatic hydrocarbon, is not conducive to the extraction of the light aromatic hydrocarbon, and reduces the quality of the light aromatic hydrocarbon gasoline; therefore, it is necessary to remove the heavy aromatic hydrocarbon.
[0003] In this process production, the stable column bottom material is generally transported to the light aromatic hydrocarbon fractionation column in the rear section. In the aromatization production process, the light aromatic hydrocarbon fractionation column has the highest energy consumption. In the light aromatic hydrocarbon fractionation column, a very high temperature is required to distill the light aromatic hydrocarbon to the top through rectification, which requires the utility system to provide a large amount of heat source, and the energy consumption is correspondingly increased, and the production cost is correspondingly increased. Therefore, an effective device is needed for separating the mixed aromatic oil produced in the aromatization device to extract the heavy aromatic oil, so as to reduce the energy consumption of the fractionation column and the energy consumption and production cost of the aromatization device. SUMMARY
[0004] In order to overcome the defects of the prior art, the technical problem to be solved by the present application is to provide a stable column bottom fractionation system of an aromatization device and a method for extracting heavy aromatic oil, so as to solve the problem of high energy consumption when separating heavy aromatic hydrocarbon and light aromatic hydrocarbon in the light aromatic hydrocarbon fractionation column of the aromatization device, and to improve the quality of the light aromatic oil.
[0005] To achieve this purpose, the following technical solutions are adopted in the present application: The present application provides a stable column bottom fractionation system of an aromatization device, which comprises a stable column and a vapor box. A vertical reboiler is arranged between the stable column and the vapor box. Upper and lower heads are arranged at both ends of the vertical reboiler. Upper and lower tube sheets are fixedly arranged near the upper and lower heads of the vertical reboiler, respectively. The upper and lower tube sheets divide the vertical reboiler into a liquid collecting cavity, a heat exchange cavity and a separation cavity in a separation direction. A liquid outlet is arranged at the bottom of the lower head. A liquid collecting structure matched with the liquid outlet is further arranged at the bottom of the vertical reboiler. A plurality of heat exchange pipes are uniformly arranged in the heat exchange cavity. The heat exchange pipes are integrally formed at both ends with the upper and lower tube sheets, so as to communicate the separation cavity and the liquid collecting cavity. The heat exchange cavity is communicated with the vapor box. The oil and gas inlet of the stable column is communicated with the separation cavity. The oil and gas outlet of the stable column is communicated with the liquid collecting cavity.
[0006] The preferred technical scheme of the present application is that the heat exchange cavity is provided with a steam inlet close to the upper tube plate, the steam inlet is communicated with the gas outlet of the steam tank, the heat exchange cavity is provided with a steam outlet close to the lower tube plate, and the steam outlet is communicated with the gas inlet of the steam tank.
[0007] The preferred technical scheme of the present application is that the liquid collecting structure comprises a sleeve type oil-gas pipe and an oil collecting pipe, the diameter of the oil-gas pipe is smaller than that of the oil collecting pipe, the bottom of the oil collecting pipe and the pipe wall of the oil-gas pipe are integrally formed, the gas outlet of the oil-gas pipe extends into the liquid collecting cavity through the liquid outlet, the oil collecting pipe is flange-connected with the liquid outlet, the oil collecting pipe is provided with an oil outlet close to the bottom, the upper head is provided with a light aromatic hydrocarbon outlet, the light aromatic hydrocarbon outlet is communicated with the oil-gas inlet of the stabilizing tower, and the oil-gas outlet of the stabilizing tower is communicated with the oil-gas pipe.
[0008] The preferred technical scheme of the present application is that the oil-gas pipe is provided with a pipe opening blind plate at the discharging end, and the lateral hole rate of the discharging end of the oil-gas pipe is 40%, so that the mixed aromatic hydrocarbon can be uniformly distributed.
[0009] A method for extracting heavy aromatic hydrocarbon oil by using a stabilizing tower bottom fractionation system of an aromatization device, comprising the following steps: S00, high-temperature steam in a steam tank enters a heat exchange cavity through a steam inlet, and the steam returns to the steam tank from a steam outlet after heat exchange, and the circulation is continuously performed in the fractionation process, while mixed aromatic hydrocarbon oil gas from a stabilizing tower enters a liquid collecting cavity of a vertical reboiler through a pipe line by an oil-gas pipe; S10, after the mixed aromatic hydrocarbon oil gas enters the liquid collecting cavity, then enters the heat exchange pipe through the lower tube plate to exchange heat with the high-temperature steam in the heat exchange cavity, the oil gas is gasified after the heat exchange is completed, and then enters a separation cavity through the upper tube plate, and finally returns to the stabilizing tower through a light aromatic hydrocarbon outlet to exchange heat and cool with the liquid phase in the tower, and the heavy aromatic hydrocarbon is enriched in the liquid collecting cavity; S20, the heavy aromatic hydrocarbon oil enriched in the liquid collecting cavity is discharged through an oil outlet for collection.
[0010] The steam inlet, the steam outlet, the oil outlet and the light aromatic hydrocarbon outlet are all provided with oil switch valves; and in step S10, the outlet end of the oil-gas pipe extends into the liquid collecting cavity by at least 20 cm, so as to facilitate the collection of the heavy aromatic hydrocarbon oil.
[0011] The present application has the following beneficial effects: Through the reform of the stabilizing tower bottom reboiler and the sleeve type design, the present application realizes the effective separation of the heavy aromatic hydrocarbon oil and the light aromatic hydrocarbon oil from the stabilizing tower bottom, reduces the heat source supply of the subsequent light aromatic hydrocarbon fractionation tower, and achieves the purpose of energy saving and consumption reduction. BRIEF DESCRIPTION OF DRAWINGS
[0012] Figure 1is a schematic diagram of the principle of a stable column bottom fractionation system of an aromatization device provided in the specific embodiment of the present application; Figure 2 is a schematic diagram of the structure of a vertical reboiler provided in the specific embodiment of the present application; Figure 3 is a schematic diagram of the principle of a vertical liquid collecting structure provided in the specific embodiment of the present application; in the figure: 1, stable column; 2, vapor box; 3, vertical reboiler; 31, upper head; 32, lower head; 33, upper tube plate; 34, lower tube plate; 301, liquid collecting cavity; 302, heat exchange cavity; 303, separation cavity; 3011, liquid outlet; 35, liquid collecting structure; 3021, heat exchange pipe; 3022, vapor inlet; 3023, vapor outlet; 351, oil gas pipe; 352, oil collecting pipe; 3521, oil outlet; 311, light aromatic hydrocarbon outlet; 3511, pipe opening blank. Specific embodiment
[0013] The technical solutions of the present application will be further described below in combination with the drawings and through specific embodiments.
[0014] As shown in the figure, a stable column bottom fractionation system of an aromatization device and a method for extracting heavy aromatic oil, comprising a stable column 1 and a vapor box 2, a vertical reboiler 3 is arranged between the stable column 1 and the vapor box 2, upper and lower heads 31 and 32 are arranged at both ends of the vertical reboiler 3, an upper tube plate 33 and a lower tube plate 34 are respectively fixedly arranged near the upper and lower heads 31 and 32 of the vertical reboiler 3, the upper and lower tube plates 33 and 34 divide the vertical reboiler 3 into a liquid collecting cavity 301, a heat exchange cavity 302 and a separation cavity 303 in the separation direction, and a liquid outlet 3011 is arranged at the bottom of the lower head 32; a liquid collecting structure 35 is further arranged at the bottom of the vertical reboiler 3 and cooperates with the liquid outlet 3011; a plurality of heat exchange pipes 3021 are uniformly arranged in the heat exchange cavity 302, the heat exchange pipes 3021 are integrally formed at both ends with the upper and lower tube plates 33 and 34, so as to communicate the separation cavity 303 and the liquid collecting cavity 301 through the heat exchange pipes 3021, the heat exchange cavity 302 and the vapor box 2 are communicated, the oil gas inlet of the stable column 1 and the separation cavity 303 are communicated, and the oil gas outlet of the stable column 1 and the liquid collecting cavity 301 are communicated. The main principle of the present case is to utilize the different boiling points of light aromatic hydrocarbons and heavy aromatic hydrocarbons in mixed aromatic hydrocarbons, the boiling point of light aromatic hydrocarbons is low, and the boiling point of heavy aromatic hydrocarbons is high, so that the energy consumption of the light aromatic hydrocarbon fractionation column is reduced by using the vertical reboiler 3, the light aromatic hydrocarbons are more easily vaporized by using the vapor box 2 as a stable heat source, the heavy aromatic hydrocarbons have high boiling points and are not easy to vaporize, so the heavy aromatic oil can be enriched at the bottom of the vertical reboiler 3, so as to realize the separation of light aromatic oil and heavy aromatic oil, which reduces the supply of heat source of the light aromatic hydrocarbon fractionation column, saves energy and reduces consumption, and effectively separates light aromatic oil and heavy aromatic oil.
[0015] Preferably, in order to facilitate the heat exchange cycle of the steam, the heat exchange cavity 302 is provided with a steam inlet 3022 near the upper tube plate 33, the steam inlet 3022 is in communication with the gas outlet of the steam tank 2, and the heat exchange cavity 302 is provided with a steam outlet 3023 near the lower tube plate 34, the steam outlet 3023 is in communication with the gas inlet of the steam tank 2. In this way, high-temperature steam can be continuously generated from the steam tank 2, enter the heat exchange cavity 302 for heat exchange from the steam inlet 3022, and after heat exchange, the steam is discharged from the heat exchange cavity 302 and returns to the steam tank 2. In this way, the high-temperature steam can continuously flow and circulate in the heat exchange cavity 302, and continuously exchange heat with the heat exchange pipe 3021, thereby improving the heat exchange efficiency.
[0016] Preferably, in order to facilitate the collection of heavy aromatic oil enriched at the bottom of the vertical reboiler 3, the liquid collecting structure 35 includes a sleeve type oil gas pipe 351 and an oil collecting pipe 352, the diameter of the oil gas pipe 351 is smaller than the diameter of the oil collecting pipe 352, the bottom of the oil collecting pipe 352 and the pipe wall of the oil gas pipe 351 are integrally formed, the gas outlet of the oil gas pipe 351 extends to the liquid collecting cavity 301 through the liquid outlet 3011, the oil collecting pipe 352 is flange connected with the liquid outlet 3011, and the oil collecting pipe 352 is provided with an oil outlet 3521 near the bottom. In this way, when heavy aromatic oil is enriched at the bottom of the liquid collecting cavity 301, the heavy aromatic oil can leave from the gap between the oil gas pipe 351 and the oil collecting pipe 352 due to the sleeve type design of the oil gas pipe 351 and the oil collecting pipe 352, and finally be collected through the oil outlet 3521. Further, the upper head 31 is provided with a light aromatic outlet 311, the light aromatic outlet 311 is in communication with the oil gas inlet of the stabilizer column 1, and the oil gas outlet of the stabilizer column 1 is in communication with the oil gas pipe 351; so as to facilitate the mixed aromatic entering the vertical reboiler 3 for heating, thereby reducing the energy consumption of the light aromatic fractionating column in subsequent production. Further, the discharge end of the oil gas pipe 351 is fixedly provided with a pipe opening blind plate 3511, and the discharge end of the oil gas pipe 351 is laterally perforated at a rate of 40%, so that the mixed aromatic forms a uniform distribution in the liquid collecting cavity 301, thereby facilitating the separation of heavy aromatic.
[0017] A method for extracting heavy aromatic oil by using a stabilizing column bottom fractionation system of an aromatization device, comprising the following steps: S00: high-temperature steam in a steam tank 2 enters a heat exchange cavity 302 through a steam inlet 3022, and after heat exchange, the steam returns to the steam tank 2 from a steam outlet 3023, and the circulation is continuously carried out during the fractionation process, while mixed aromatic oil gas from the stabilizing column 1 enters a liquid collecting cavity 301 of a vertical reboiler 3 through an oil gas pipe 351 by a pump group; S10: after the mixed aromatic oil gas enters the liquid collecting cavity 301, then the oil gas is heated through a lower tube plate 34 and the high-temperature steam in the heat exchange cavity 302, and after the oil gas is gasified, the oil gas enters a separation cavity 303 through an upper tube plate 33, and finally, the oil gas returns to the stabilizing column 1 through a light aromatic outlet 311 and exchanges heat with liquid in the column, and heavy aromatic oil is enriched in the liquid collecting cavity 301; S20: the heavy aromatic oil enriched in the liquid collecting cavity 301 is discharged through an oil outlet 3521 for collection. In step S00, the oil gas of the mixed aromatic oil from the stabilizing column 1 entering the liquid collecting cavity 301 is in a liquid-gas mixed state, and is in a state of more oil and less gas, at this time, heavy aromatic oil liquid with high boiling point in a liquid state can be enriched in the liquid collecting cavity 301, and is discharged through the oil outlet 3521 for collection to achieve the purpose of separation; then, the gaseous light aromatic oil is heated in the heat exchange cavity, which can achieve the purpose of preheating, that is, the heat source supply of the light aromatic fractionation column in the subsequent section is reduced, and the heavy aromatic oil liquid with high boiling point can be further enriched in the liquid collecting cavity 301 for discharge, so that the effective separation of the heavy aromatic oil and the light aromatic oil and the energy-saving and consumption-reducing purposes are efficiently achieved.
[0018] Preferably, the steam inlet 3022, the steam outlet 3023, the oil outlet 3521 and the light aromatic outlet 311 are all provided with oil switch valves; so as to facilitate connection and control; further in step S10, an outlet end of the oil gas pipe 351 extends into the liquid collecting cavity 301 by at least 20 cm, so as to facilitate uniform distribution of the mixed aromatic oil in the liquid collecting cavity 301, and also facilitate collection of the separated heavy aromatic oil.
[0019] The present application is described by preferred embodiments, and those skilled in the art know that various changes or equivalent replacements can be made to the features and embodiments without departing from the spirit and scope of the present application. The present application is not limited by the specific embodiments disclosed herein, and other embodiments falling within the scope of the claims of the present application all belong to the scope of protection of the present application.
Claims
1. A stable bottom fractionation system for an aromatization unit, characterized by: The invention comprises a stabilizing tower (1) and a steam box (2), wherein a vertical reboiler (3) is provided between the stabilizing tower (1) and the steam box (2), an upper head (31) and a lower head (32) are provided at both ends of the vertical reboiler (3), an upper tube plate (33) and a lower tube plate (34) are fixedly provided near the upper head (31) and the lower head (32), respectively, the upper tube plate (33) and the lower tube plate (34) divide the vertical reboiler (3) into a liquid collecting chamber (301), a heat exchange chamber (302) and a separation chamber (303) according to a separation direction, and a liquid outlet (3011) is provided at the bottom of the lower head (32); and a liquid collecting structure (35) cooperating with the liquid outlet (3011) is also provided at the bottom of the vertical reboiler (3); A plurality of heat exchange tubes (3021) are evenly arranged in the heat exchange cavity (302), and both ends of the heat exchange tubes (3021) are integrally formed with the upper tube plate (33) and the lower tube plate (34), so that the heat exchange tubes (3021) connect the separation cavity (303) and the liquid collecting cavity (301), the heat exchange cavity (302) and the steam box (2) are connected, the oil and gas inlet of the stabilizing tower (1) and the separation cavity (303) are connected, and the oil and gas outlet of the stabilizing tower (1) and the liquid collecting cavity (301) are connected.
2. The stable bottom fractionation system of an aromatization unit according to claim 1, characterized in that: The heat exchange chamber (302) is provided with a steam inlet (3022) near the upper tube plate (33), and the steam inlet (3022) is communicated with the air outlet of the steam box (2). The heat exchange chamber (302) is provided with a steam outlet (3023) near the lower tube plate (34), and the steam outlet (3023) is communicated with the air inlet of the steam box (2).
3. The aromatization unit stable bottom fractionation system according to claim 2, characterized in that: The liquid collecting structure (35) comprises an oil and gas pipe (351) and an oil collecting pipe (352) arranged in a sleeve-type manner. The diameter of the oil and gas pipe (351) is smaller than the diameter of the oil collecting pipe (352). The bottom of the oil collecting pipe (352) and the pipe wall of the oil and gas pipe (351) are integrally formed. The gas outlet of the oil and gas pipe (351) extends into the liquid collecting cavity (301) through the liquid outlet (3011). The oil collecting pipe (352) is flange-connected to the liquid outlet (3011). The oil collecting pipe (352) is provided with an oil outlet (3521) near the bottom.
4. The stable bottom fractionation system of an aromatization unit according to claim 3, characterized in that: The upper head (31) is provided with a light aromatics outlet (311), the light aromatics outlet (311) is communicated with the oil and gas inlet of the stabilization tower (1), and the oil and gas outlet of the stabilization tower (1) is communicated with the oil and gas pipe (351).
5. The aromatization unit stable bottom fractionation system according to claim 3, characterized in that: The discharge end of the oil and gas pipe (351) is fixedly provided with a pipe orifice blind plate (3511), and the lateral opening rate of the discharge end of the oil and gas pipe (351) is 40%.
6. A method for extracting heavy aromatic oil using a bottom fractionation system of a stabilizer tower of an aromatization device, wherein the bottom fractionation system of the stabilizer tower (1) of the aromatization device is the fractionation system according to any one of claims 2 to 4, characterized in that: The following steps are involved: S00: The high-temperature steam in the steam box (2) enters the heat exchange chamber (302) from the steam inlet (3022). After heat exchange, the steam returns to the steam box (2) from the steam outlet (3023) and circulates continuously during the fractionation process. At the same time, the mixed aromatic oil and gas from the stabilization tower (1) is pumped through the pipeline and the oil and gas pipe (351) into the liquid collecting chamber (301) of the vertical reboiler (3); S10: After the mixed aromatic oil and gas enter the liquid collecting chamber (301), they enter the heat exchange tube (3021) through the lower tube plate (34) to exchange heat with the high-temperature steam in the heat exchange chamber (302). After the heat exchange is completed, the oil and gas are vaporized and enter the separation chamber (303) through the upper tube plate (33). Finally, they return to the stabilization tower (1) through the light aromatics outlet (311) to exchange heat with the liquid phase in the tower for cooling, and the heavy aromatics are enriched in the liquid collecting chamber (301); S20: The heavy aromatic oil accumulated in the liquid collecting chamber (301) is discharged through the oil outlet (3521) for collection.
7. The method for extracting heavy aromatic oil according to claim 6, wherein: The steam inlet (3022), the steam outlet (3023), the oil outlet (3521) and the light aromatics outlet (311) are all provided with oil switching valves.
8. The method for extracting heavy aromatic oil according to claim 6, wherein: In step S10, the outlet end of the oil and gas pipe (351) extends into the liquid collecting chamber (301) by at least 20 cm.