A phthalic anhydride distillation device for reducing coking of a light component column reboiler

Abstract

The utility model relates to a field of chemical equipment, concretely relates to a phthalic anhydride rectification device reducing coking of light component column reboiler, including crude phthalic anhydride tank, light component column and heavy component column, be connected with feed pipeline between crude phthalic anhydride tank and light component column, be equipped with light component production pipeline and phthalic anhydride production pipeline on the light component column, be equipped with heavy component overflow pipeline in the light component column, the bottom of light component column is equipped with first reboiler, be equipped with first inlet pipeline, first outlet pipeline and heavy component production pipeline on the first reboiler, heavy component production pipeline is connected with material return pipeline and heavy component column feed pipeline. Through setting up heavy component production pipeline on the first reboiler at the bottom of light component column, can control heavy component production at the bottom of light component column, and can realize heavy component flow in reboiler, reduce heavy component deposition in reboiling, coking.

Description

Technical Field

[0001] This utility model relates to the field of chemical equipment, specifically to a phthalic anhydride distillation device for reducing coking in the reboiler of a light component tower. Background Technology

[0002] Phthalic anhydride, also known as phthalic anhydride, is a very important organic chemical raw material. Its core process involves mixing purified air with vaporized o-xylene, and then subjecting the mixture to a gas-phase oxidation reaction at high temperature (approximately 400-460°C) and with a vanadium-based catalyst to produce phthalic anhydride. The large amount of heat generated by the reaction is removed by molten salt circulating outside the tubes, and steam may be produced as a byproduct. After cooling, the phthalic anhydride sublimates into a solid, which is then purified through melting, vacuum distillation, and other steps to obtain the final product.

[0003] The distillation section typically includes a light component column and a heavy component column. The light component column usually transfers heavy components from the bottom to the heavy component column via overflow, resulting in lower material flow at the bottom of the light component column. This causes heavy components to easily deposit in the reboiler and at the bottom of the light component column. The enrichment of heavy components, coupled with the high-temperature environment, easily leads to coking on the surface of the heat exchange tubes in the reboiler of the light component column, reducing evaporation and affecting the distillation separation efficiency. As the evaporation rate decreases, the process operation reduces the pressure inside the column. When the enriched heavy components reach their boiling point, they also evaporate and enter the valve trays and packing layer, causing coking, adhesion, and increased resistance in the trays and valves, further deteriorating the operating conditions within the column. Utility Model Content

[0004] In order to overcome the problem that coking is easy to occur in the light component column of the existing phthalic anhydride distillation unit, which affects the distillation and separation effect of the light component column, this utility model provides a phthalic anhydride distillation unit that reduces coking in the reboiler of the light component column.

[0005] In view of this, the present invention provides a phthalic anhydride distillation apparatus for reducing coking in the reboiler of the light component column, comprising a crude phthalic anhydride tank, a light component column, and a heavy component column. A feed line connects the crude phthalic anhydride tank and the light component column. The light component column is provided with a light component outlet line and a phthalic anhydride outlet line. A heavy component overflow line is provided inside the light component column. A first reboiler is provided at the bottom of the light component column. The first reboiler is provided with a first inlet line, a first outlet line, and a heavy component outlet line. The heavy component outlet line is connected to a discharge line and a heavy component column feed line.

[0006] Preferably, the recombinant overflow pipeline is provided with an overflow port, and the other end of the recombinant overflow pipeline is connected to the recombinant tower.

[0007] Preferably, the other end of the light component extraction pipeline is connected to a light component storage tank, and the other end of the phthalic anhydride extraction pipeline is connected to a phthalic anhydride storage tank.

[0008] Preferably, the recombinant extract pipeline is equipped with a delivery pump.

[0009] Preferably, a first solenoid valve is provided on the recombinant extract pipeline.

[0010] Preferably, a second solenoid valve is provided on the discharge pipeline, and a third solenoid valve is provided on the feed pipeline of the recombining tower.

[0011] Preferably, the other end of the discharge pipeline is connected to the crude phthalic anhydride tank, and the other end of the feed pipeline of the recombining column is connected to the recombining column.

[0012] Preferably, the recombining tower is equipped with a recombining tower extraction pipeline, the other end of which is connected to an intermediate storage tank, and the intermediate storage tank is equipped with a crude phthalic anhydride tank replenishment pipeline.

[0013] Preferably, the recombining tower is equipped with a residual liquid extraction pipeline, and the other end of the residual liquid extraction pipeline is connected to a residual liquid storage tank.

[0014] Preferably, the bottom of the recombining column is provided with a second reboiler, and the second reboiler is provided with a second inlet pipeline and a second outlet pipeline.

[0015] The beneficial effects of this invention are as follows: This invention provides a phthalic anhydride distillation apparatus for reducing coking in the reboiler of the light component column, comprising a crude phthalic anhydride tank, a light component column, and a heavy component column. A feed line connects the crude phthalic anhydride tank and the light component column. The light component column is equipped with a light component outlet line and a phthalic anhydride outlet line. A heavy component overflow line is located inside the light component column. A first reboiler is located at the bottom of the light component column, and the first reboiler is equipped with a first inlet line, a first outlet line, and a heavy component outlet line. The heavy component outlet line is connected to a discharge line and a heavy component column feed line. By setting a heavy component outlet line on the first reboiler at the bottom of the light component column, the discharge of heavy components from the bottom of the light component column can be controlled, and the heavy components can flow within the reboiler, reducing deposition and coking of heavy components in the reboiler. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0017] Figure 1 This is a schematic diagram of a phthalic anhydride distillation apparatus for reducing coking in the reboiler of the light component tower, as described in this embodiment of the present invention.

[0018] The component names and their numbers in the diagram are as follows: 1. Crude phthalic anhydride tank; 2. Light component tower; 21. First reboiler; 211. First inlet pipeline; 212. First outlet pipeline; 213. Heavy component extraction pipeline; 2131. First solenoid valve; 214. Unloading pipeline; 2141. Second solenoid valve; 215. Heavy component tower feed pipeline; 2151. Third solenoid valve; 22. Light component extraction pipeline; 23. Phthalic anhydride extraction pipeline; 24. Feed pipeline; 25. Heavy component overflow pipeline; 251. Overflow outlet; 3. Phthalic anhydride storage tank; 4. Light component storage tank; 5. Heavy component tower; 51. Second reboiler; 511. Second inlet pipeline; 512. Second outlet pipeline; 52. Heavy component tower extraction pipeline; 53. Residual liquid extraction pipeline; 6. Intermediate storage tank; 61. Crude phthalic anhydride tank replenishment pipeline; 7. Residual liquid storage tank. Detailed Implementation

[0019] To make the technical problems, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0020] It should be noted that when a component is referred to as "connected to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0021] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0022] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0023] Throughout this specification, reference to "an embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of this application. Therefore, the phrases "in one embodiment," "in some embodiments," or "in some of these embodiments" appear in various places throughout the specification, and not all refer to the same embodiment. Furthermore, in one or more embodiments, a particular feature, structure, or characteristic may be combined in any suitable manner.

[0024] Referring to the crude phthalic anhydride tank 1 in the figure, this utility model provides a phthalic anhydride distillation apparatus for reducing coking in the reboiler of the light component tower. It includes a crude phthalic anhydride tank 1, a light component tower 2, and a heavy component tower 5. The phthalic anhydride to be distilled is stored in the crude phthalic anhydride tank 1. A feed line 24 connects the crude phthalic anhydride tank 1 and the light component tower 2. The light component tower 2 is equipped with a light component outlet line 22 and a phthalic anhydride outlet line 23. Light components, such as maleic anhydride and benzoic acid, are collected from the light component outlet line 22, and qualified finished phthalic anhydride is collected from the phthalic anhydride outlet line 23. A heavy component overflow line 25 is located inside the light component tower 2, and the other end of the heavy component overflow line 25 is connected to the heavy component tower 5. The heavy component overflow line 25 is equipped with... Overflow outlet 251: When the liquid level at the bottom of light component tower 2 is higher than overflow outlet 251, it will automatically overflow into heavy component tower 5. The bottom of light component tower 2 is equipped with a first reboiler 21, and the first reboiler 21 is equipped with a heavy component collection pipeline 213. The heavy component at the bottom of light component tower 2 can be discharged through the heavy component collection pipeline 213. The heavy component collection pipeline 213 is connected to a discharge pipeline 214 and a heavy component tower feed pipeline 215. The other end of the discharge pipeline 214 is connected to the crude phthalic anhydride tank 1. The heavy component at the bottom of light component tower 2 can be discharged into the crude phthalic anhydride tank 1 through the discharge pipeline 214. The other end of the heavy component tower feed pipeline 215 is connected to the heavy component tower 5.

[0025] The phthalic anhydride distillation apparatus for reducing coking in the reboiler of the light component column provided by this utility model adds a heavy component extraction pipeline 213 to the first reboiler 21. The heavy component at the bottom of the light component column 2 can be transported out of the bottom of the light component column 2 through the heavy component extraction pipeline 213 and flow in the first reboiler 21, thereby reducing the deposition of heavy component at the bottom of the light component column 2 in the first reboiler 21. The interior of the light component column 2 is equipped with heating tubes, which also reduces coking of heavy component on the heating tubes.

[0026] Specifically, the light component outlet pipeline 22 is located at the top of the light component tower 2, the phthalic anhydride outlet pipeline 23 is located below the light component outlet pipeline 22, and the inlet of the feed pipeline 24 into the light component tower 2 is located below the phthalic anhydride outlet pipeline 23. The first reboiler 21 is equipped with an inlet tube, and is connected to a first inlet pipeline 211 and a first outlet pipeline 212. The heavy components at the bottom of the light component tower 2 enter the first reboiler 21 through the first inlet pipeline 211. After being heated again in the first reboiler 21, the components with lower boiling points are vaporized and then re-enter the light component tower 2 through the first outlet pipeline 212 for separation. The heavier heavy components remain in the first reboiler 21. The heavier heavy components can be discharged from the first reboiler 21 through the heavy component outlet pipeline 213 and flow within the first reboiler 21, reducing the deposition of heavy components on the heating tubes within the first reboiler 21 and preventing carbon buildup.

[0027] Furthermore, a transfer pump (not shown in the figure) is installed on the heavy component extraction pipeline 213, a second solenoid valve 2141 is installed on the discharge pipeline 214, and a third solenoid valve 2151 is installed on the heavy component tower feed pipeline 215. The flow rate of the heavy component entering the crude phthalic anhydride tank 1 can be controlled by controlling the second solenoid valve 2141, and the flow rate of the heavy component entering the heavy component tower 5 can be controlled by controlling the third solenoid valve 2151. A first solenoid valve 2131 is also installed on the heavy component extraction pipeline 213 for emergency discharge.

[0028] Furthermore, the other end of the light component extraction pipeline 22 is connected to a light component storage tank 4, which is used to store the light component extracted from the light component extraction pipeline 22 at the top of the light component tower 2. The other end of the phthalic anhydride extraction pipeline 23 is connected to a phthalic anhydride storage tank 3, which is used to store the finished phthalic anhydride extracted from the phthalic anhydride extraction pipeline 23. In some embodiments, the phthalic anhydride storage tank 3 is equipped with a heat preservation device to store the phthalic anhydride in a liquid state.

[0029] Furthermore, the crude phthalic anhydride tank 1 is equipped with a heating coil. By heating, the crude phthalic anhydride to be refined stored in the crude phthalic anhydride tank 1 is stored in a liquid state, which facilitates its transfer to the light component tower 2.

[0030] Furthermore, the upper part of the heavy fractionation tower 5 is equipped with a heavy fractionation tower outlet pipeline 52, the other end of which is connected to an intermediate storage tank 6. The phthalic anhydride-containing component in the heavy fractionation tower 5 is extracted from the heavy fractionation tower outlet pipeline 52 and stored in the intermediate storage tank 6. The intermediate storage tank 6 is also equipped with a crude phthalic anhydride tank replenishment pipeline 61, the other end of which is connected to the crude phthalic anhydride tank 1, so that the phthalic anhydride-containing component stored in the intermediate storage tank 6 can be transported to the crude phthalic anhydride tank 1. The bottom of the heavy fractionation tower 5 is equipped with a second reboiler 51, which is equipped with a second inlet pipeline 511 and a second outlet pipeline 512. The liquid at the bottom of the heavy fractionation tower 5 enters the second reboiler 51 from the second inlet pipeline 511, vaporizes, and then enters the heavy fractionation tower 5 from the second outlet pipeline 512 for separation. The bottom of the recombining column 5 is also equipped with a residual liquid collection pipeline 53. The other end of the residual liquid collection pipeline 53 is connected to a residual liquid storage tank 7. The residual liquid in the recombining column 5 can be collected through the residual liquid collection pipeline 53 and stored in the residual liquid storage tank 7.

[0031] The phthalic anhydride distillation apparatus for reducing coking in the reboiler of the light component tower provided by this utility model has a heavy component extraction pipeline 213 installed at the bottom of the light component tower 2, and a transfer pump installed on the heavy component extraction pipeline 213. By controlling the start and stop of the pump, the heavy components enriched at the bottom of the light component tower 2 can be intermittently transported out of the bottom of the light component tower 2 and liquid flow can be achieved in the first reboiler 21. This can reduce the deposition of heavy components in the first reboiler 21 and reduce the formation of carbon deposits after heating.

[0032] Based on the above-described preferred embodiments of this utility model, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the scope of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A phthalic anhydride distillation apparatus for reducing coking in the reboiler of a light component column, characterized in that: The system includes a crude phthalic anhydride tank (1), a light component tower (2), and a heavy component tower (5). A feed line (24) is connected between the crude phthalic anhydride tank (1) and the light component tower (2). The light component tower (2) is equipped with a light component outlet line (22) and a phthalic anhydride outlet line (23). The light component tower (2) is equipped with a heavy component overflow line (25). The bottom of the light component tower (2) is equipped with a first reboiler (21). The first reboiler (21) is equipped with a first inlet line (211), a first outlet line (212), and a heavy component outlet line (213). The heavy component outlet line (213) is connected to a discharge line (214) and a heavy component tower feed line (215).

2. The phthalic anhydride distillation apparatus for reducing coking in the reboiler of the light component tower according to claim 1, characterized in that: The overflow pipeline (25) of the recombinant component is provided with an overflow port (251), and the other end of the overflow pipeline (25) is connected to the recombinant component tower (5).

3. The phthalic anhydride distillation apparatus for reducing coking in the reboiler of the light component tower according to claim 1, characterized in that: The other end of the light component extraction pipeline (22) is connected to the light component storage tank (4), and the other end of the phthalic anhydride extraction pipeline (23) is connected to the phthalic anhydride storage tank (3).

4. The phthalic anhydride distillation apparatus for reducing coking in the reboiler of the light component tower according to claim 1, characterized in that: The recombinant extraction pipeline (213) is equipped with a delivery pump.

5. The phthalic anhydride plant with reduced coking of the light ends column reboiler of claim 1, wherein: The first solenoid valve (2131) is installed on the recombinant extraction pipeline (213).

6. The phthalic anhydride distillation apparatus for reducing coking in the reboiler of the light component tower according to claim 1, characterized in that: The discharge pipeline (214) is equipped with a second solenoid valve (2141), and the recombination tower feed pipeline (215) is equipped with a third solenoid valve (2151).

7. The phthalic anhydride plant with reduced coking of the light ends column reboiler of claim 1, wherein: The other end of the discharge pipeline (214) is connected to the crude phthalic anhydride tank (1), and the other end of the recombinant fraction tower feed pipeline (215) is connected to the recombinant fraction tower (5).

8. The phthalic anhydride distillation apparatus for reducing coking in the reboiler of the light component tower according to claim 1, characterized in that: The recombining tower (5) is provided with a recombining tower extraction pipeline (52), and the other end of the recombining tower extraction pipeline (52) is connected to the intermediate storage tank (6). The intermediate storage tank (6) is provided with a crude phthalic anhydride tank replenishment pipeline (61).

9. The phthalic anhydride distillation apparatus for reducing coking in the reboiler of the light component tower according to claim 1, characterized in that: The recombination tower (5) is equipped with a residual liquid extraction pipeline (53), and the other end of the residual liquid extraction pipeline (53) is connected to the residual liquid storage tank (7).

10. The phthalic anhydride distillation apparatus for reducing coking in the reboiler of the light component tower according to claim 1, characterized in that: The bottom of the recombination column (5) is provided with a second reboiler (51), and the second reboiler (51) is provided with a second inlet pipeline (511) and a second outlet pipeline (512).

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