Rectification device for naphthalene-process phthalic anhydride industrial naphthalene
By designing a distillation device including the first reactor, the second reactor and the distillation tower in the naphthalene phthalic anhydride production process, the heat exchange technology liquefies the heavy components in the naphthalene steam, and the distillation tower blockage is solved by liquefaction using heat exchange technology. and frequent cleaning of problems improve equipment stability and production efficiency.
Patent Information
- Application Number
- CN202420098055.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-16
- Publication Date
- 2025-02-14
- Estimated Expiration
- 2034-01-16
AI Technical Summary
In the existing naphthalene phthalanhydride production process, the heavy component impurities in tar naphthalene are easily cured during the distillation process, resulting in blockage of the distillation tower and requiring frequent cleaning, affecting the stable operation of the equipment.
A distillation device including a first reactor, a second reactor and a distillation tower is designed, and the high boiling point of the heavy components in naphthalene steam is utilized through heat exchange between the second reactor and the first reactor. Characteristics to achieve its large amount of liquefaction, thereby reducing the content of heavy components entering the distillation column.
It effectively reduces the chance of distillation tower being blocked, reduces the need for cleaning the distillation tower, and improves the stable operation and production efficiency of the equipment.
Smart Images
Figure CN222468081U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of pre-treatment equipment for phthalic anhydride production, in particular to a rectification device for industrial naphthalene of phthalic anhydride produced by the naphthalene process. Background Art
[0002] Phthalic anhydride, also known as phthalic anhydride, is a white flaky solid or powder, or white needle-shaped crystals with a slight odor. It is easy to sublime, slightly soluble in cold water, easily soluble in hot water and hydrolyzed into phthalic acid, soluble in ethanol, benzene and pyridine, and slightly soluble in ether. There are two main process routes for the production of phthalic anhydride: the gas phase oxidation method of industrial naphthalene and the gas phase oxidation method of o-xylene. The basic process of phthalic anhydride production by the naphthalene method is as follows: air is sent to the air preheater by a blower through a filter, industrial naphthalene is heated and vaporized in the evaporator, and the vaporized naphthalene enters the naphthalene-air mixer and is fully mixed with the preheated air. The mixed gas of naphthalene and air enters the fixed bed reactor and reacts under the action of a catalyst to generate gaseous phthalic anhydride. The gaseous phthalic anhydride is then condensed and hot-melted to obtain crude liquid phthalic anhydride, and the finished phthalic anhydride is obtained after distillation. There are many factors that affect the quality of phthalic anhydride. In the process of o-xylene reacting with air in the presence of a catalyst to produce phthalic anhydride, maleic anhydride, benzoic acid, citraconic anhydride, phthalide, anthraquinone, etc. are generated as side reactions, among which phthalide, anthraquinone, citraconic anhydride, benzoic acid, etc. are the main factors affecting the color number; in the process of industrial naphthalene reacting with air in the presence of a catalyst to produce phthalic anhydride, naphthoquinone, maleic anhydride, benzoic acid, etc. are generated as side reactions, among which benzoic acid, naphthoquinone, etc. are the main factors affecting the product color number.
[0003] There are two main sources of industrial naphthalene. The first is tar naphthalene extracted from coal tar. Naphthalene accounts for about 8% to 12% in high-temperature coal tar. Cut out the naphthalene oil fraction with a temperature range of 210 to 230°C from the side line of the tar distillation tower, wash and remove phenol, and then distill to separate the light components, and then you can get industrial naphthalene with a freezing point of 76°C and a purity of 92%; the second is petroleum naphthalene extracted from heavy aromatics in the processes of catalytic reforming, catalytic cracking and hydrocarbon cracking. In the catalytic reforming oil, the content of methylnaphthalene is about 55%. First, through extraction and adsorption, various naphthalene homologues are separated from the raw material fraction, and then the catalytic hydrodealkylation method is adopted. With chromium trioxide and aluminum trioxide as catalysts, the hydrodemethylation reaction is carried out at 400 to 800°C and 0.5 to 7 MPa. After cooling the gas phase, the reaction product is distilled to remove the light components such as benzene, toluene, and xylene, and finally further distilled to obtain petroleum naphthalene. Both methods can obtain crude naphthalene with a purity greater than 92%. Since both processes include the process of removing light components, the boiling point of impurities in the obtained crude naphthalene is a heavy component impurity higher than the boiling point of pure naphthalene. Relatively speaking, tar naphthalene is easier to obtain and has a lower market price. Therefore, it is easier to control the production cost of the enterprise by using tar naphthalene as a raw material in the production process of naphthalene-based phthalic anhydride.
[0004] But because the heavy component impurity contained in tar naphthalene can produce a lot of impurities in phthalic anhydride synthesis, this magazine directly affects the colorimetry of product phthalic anhydride, causing the colorimetry of product phthalic anhydride to be unable to meet the plasticizer with high color number requirements, and the application field is restricted, and also causes the price of phthalic anhydride with colorimetry exceeding the standard to be lower.Therefore, in the naphthalene process phthalic anhydride production process of prior art, the distillation process of industrial naphthalene based on tar naphthalene is usually increased, and then the content of naphthalene in industrial naphthalene is improved, thereby improving the production quality of product phthalic anhydride.Effectively reduce the impurity based on heavy components in industrial naphthalene, and also can reduce the technical problem of pipeline blockage caused by heavy components in industrial naphthalene. However, in the distillation process of industrial naphthalene mainly based on tar naphthalene, after the heavy components of the tar naphthalene are separated, a technical problem occurs that some of the heavy components will be solidified by cooling due to their high melting and boiling points, and the solidified heavy components will cause a partial blockage in the distillation tower used for the distillation of tar naphthalene, thereby causing the flow resistance of the distillation tower used for the distillation of tar naphthalene to be higher and higher and requiring frequent cleaning of the distillation tower, which is quite unfavorable for the stable operation of the equipment. Therefore, the distillation treatment equipment of naphthalene in the naphthalene process phthalic anhydride production process needs to be improved, thereby reducing the content of heavy components in the mixed gas transported to the distillation tower used for the distillation of tar naphthalene, thereby reducing the technical problem that the distillation tower used for the distillation of tar naphthalene frequently needs to be cleaned due to the solidification of heavy components in the packing layer of the distillation tower used for the distillation of tar naphthalene. Summary of the invention
[0005] In view of the deficiencies in the prior art, the utility model provides a distillation device for industrial naphthalene of naphthalene-based phthalic anhydride, which can reduce the heavy components in the tar naphthalene vapor entering the distillation tower, and is used to overcome the defects in the prior art.
[0006] The technical scheme adopted by the utility model is as follows: a rectification device for industrial naphthalene of naphthalene-based phthalic anhydride comprises a first reactor, a second reactor and a rectification tower, wherein the second reactor is provided with an aeration pipe, the gas phase outlet end of the first reactor is connected with the air inlet end of the aeration pipe, the rectification tower comprises a tower body and a first baffle and a second baffle which are alternately arranged in the tower body from top to bottom, the tower body below the first baffle and the second baffle is connected with the gas phase outlet end of the second reactor, the bottom end of the tower body is connected with the liquid phase inlet end of the first reactor, the inlet end of a refined naphthalene steam delivery pipe is provided at the top of the tower body, the inlet end of a condenser heat source channel is provided at the outlet end of the refined naphthalene steam delivery pipe, the outlet end of the condenser heat source channel is connected with a liquid refined naphthalene recovery tank, a wire mesh coalescer is provided in the inner cavity of the liquid refined naphthalene recovery tank above the connection point between the liquid refined naphthalene recovery tank and the condenser, and a tail gas delivery pipe is connected to the liquid refined naphthalene recovery tank above the wire mesh coalescer.
[0007] Preferably, it also includes a heat transfer oil delivery main pipe, on which a first temperature sensor is arranged, the first reactor and the second reactor each include a reactor body, a stirring device arranged on the reactor body and a jacket arranged on the reactor body, the jacket of the first reactor and the heat transfer oil delivery main pipe and the jacket of the second reactor are respectively connected through heat transfer oil delivery branches, and the heat transfer oil delivery branch pipes are provided with a first regulating valve and a liquid flow sensor.
[0008] Preferably, it also includes a heat transfer oil reflux main pipe, the heat transfer oil reflux main pipe and the jacket of the first reactor and the jacket of the second reactor are respectively connected through heat transfer oil reflux branches, and the heat transfer oil delivery branch pipe is provided with a second regulating valve and a second temperature sensor.
[0009] Preferably, the first reactor and the second reactor are respectively provided with a first liquid level sensor, the bottom end of the reactor body of the first reactor and the top end of the reactor body of the second reactor are connected through a crude naphthalene delivery pipe, and the crude naphthalene delivery pipe is provided with a first booster pump and a third regulating valve.
[0010] Preferably, a second liquid level sensor is provided on the tower body below the first baffle and the second baffle, the bottom end of the tower body and the top end of the reactor body of the first reactor are connected through a reflux liquid delivery pipe, a second one-way valve and a fourth regulating valve are provided on the reflux liquid delivery pipe, an online chromatograph is provided on the reactor body of the first reactor, a coarse slag discharge pipe is provided on the bottom end of the reactor body of the first reactor, and a fifth regulating valve is provided on the coarse slag discharge pipe.
[0011] Preferably, the first reactor and the second reactor are respectively provided with a raw material delivery pipe, the raw material delivery pipe is provided with a sixth regulating valve, the liquid refined naphthalene recovery tank is provided with a liquid refined naphthalene delivery pipe, the liquid refined naphthalene delivery pipe is provided with a seventh regulating valve and a second booster pump.
[0012] The utility model has the following beneficial effects: firstly, the utility model utilizes the second reactor to receive the naphthalene vapor transported from the first reactor, thereby allowing the naphthalene vapor to exchange heat with the industrial naphthalene in the second reactor, and utilizes the physical property that the boiling point of the heavy components in the naphthalene vapor is higher than the boiling point of pure naphthalene to achieve a large amount of liquefaction of the heavy components in the naphthalene vapor transported by the first reactor, thereby achieving the technical purpose of reducing the heavy components in the tar naphthalene vapor entering the distillation tower, reducing the probability of the distillation tower being blocked, and the distillation tower described in the product comprises a tower body and a first baffle and a second baffle alternately arranged from top to bottom in the tower body, the heat exchange path is increased by utilizing the first baffle and the second baffle, and compared with a distillation tower in the form of a packing layer, it is less likely to be blocked during the distillation of the naphthalene vapor.
[0013] Secondly, the utility model is provided with a first temperature sensor on the heat transfer oil delivery main pipe, so as to provide feedback on the temperature parameters of the medium delivered through the heat transfer oil delivery main pipe.
[0014] Finally, the heat transfer oil reflux main pipe and the jacket of the first reactor and the jacket of the second reactor described in the utility model are respectively connected through a heat transfer oil reflux branch pipe, and a second regulating valve and a second temperature sensor are provided on the heat transfer oil delivery branch pipe; the corresponding second temperature sensor is installed to facilitate the feedback of the temperature parameters of the medium transported through the corresponding heat transfer oil reflux branch pipe.
[0015] The utility model has the advantages of simple structure, convenient operation, ingenious design, greatly improved working efficiency, good social and economic benefits, and is a product that is easy to promote and use. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 It is a structural schematic diagram of the utility model.
[0017] Figure 2 for Figure 1 A partial enlarged schematic diagram of detail A. DETAILED DESCRIPTION
[0018] like Figure 1 and Figure 2 As shown, a rectification device for industrial naphthalene of naphthalene-based phthalic anhydride comprises a first reactor 1, a second reactor 2 and a rectification tower, wherein the second reactor 2 is provided with an aeration pipe 3, the aeration pipe 3 adopts a tubular structure, and one end of the aeration pipe 3 located in the second reactor 2 is evenly provided with a plurality of aeration holes; the gas phase outlet end of the first reactor 1 and the air inlet end of the aeration pipe 3 are connected through a first crude naphthalene steam conveying pipe 4, the first crude naphthalene steam conveying pipe 4 is provided with a first non-return valve 5, and the rectification tower comprises a tower body 6 and first baffles 7 and second baffles 8 alternately arranged from top to bottom in the tower body 6, and the first baffles 7 and the second baffles 8 are provided below the first baffles 7 and the second baffles 8. The gas phase outlet end of the square tower body 6 is connected to the second reactor 2 through the second crude naphthalene steam delivery pipe 9, the bottom end of the tower body 6 is connected to the liquid phase inlet end of the first reactor 1, the top of the tower body 6 is provided with the inlet end of the refined naphthalene steam delivery pipe 10, the outlet end of the refined naphthalene steam delivery pipe 10 is provided with the inlet end of the heat source channel of the condenser 11, the outlet end of the heat source channel of the condenser 11 is connected with a liquid refined naphthalene recovery tank 12, a wire mesh coalescer 13 is provided in the inner cavity of the liquid refined naphthalene recovery tank 12 above the connection point between the liquid refined naphthalene recovery tank 12 and the condenser 11, and a tail gas delivery pipe 14 is connected to the liquid refined naphthalene recovery tank 12 above the wire mesh coalescer 13.
[0019] The product also includes a heat transfer oil delivery main pipe 15 and a heat transfer oil return main pipe 20. The heat transfer oil delivery main pipe 15 is provided with a first temperature sensor 16. The first reactor 1 and the second reactor 2 both include a reactor body, a stirring device provided on the reactor body, and a jacket provided on the reactor body. The stirring device includes a stirring shaft, a stirring blade provided on the stirring shaft, and a stirring motor connected to the stirring shaft. The jacket of the first reactor 1 and the heat transfer oil delivery main pipe 15 and the jacket of the second reactor 2 are connected through a heat transfer oil delivery branch pipe 17, respectively. The heat transfer oil delivery branch pipe 17 is provided with a first regulating valve 18 and a liquid flow sensor 19. The heat transfer oil return main pipe 20 and the jacket of the first reactor 1 and the jacket of the second reactor 2 are connected through a heat transfer oil return branch pipe 21, respectively. The heat transfer oil delivery branch pipe 17 is provided with a second regulating valve 22 and a second temperature sensor 23.
[0020] The first reactor 1 and the second reactor 2 are respectively provided with a first liquid level sensor 24, the bottom end of the reactor body of the first reactor 1 and the top end of the reactor body of the second reactor 2 are connected through a crude naphthalene delivery pipe 25, and the crude naphthalene delivery pipe 25 is provided with a first booster pump 26 and a third regulating valve 27. A second liquid level sensor 28 is provided on the tower body 6 below the first baffle 7 and the second baffle 8, the bottom end of the tower body 6 and the top end of the reactor body of the first reactor 1 are connected through a reflux liquid delivery pipe 29, and the reflux liquid delivery pipe 29 is provided with a second one-way valve 30 and a fourth regulating valve 31, the reactor body of the first reactor 1 is provided with an online chromatograph 32, the bottom end of the reactor body of the first reactor 1 is provided with a coarse slag discharge pipe 33, and the coarse slag discharge pipe 33 is provided with a fifth regulating valve 34.
[0021] The first reactor 1 and the second reactor 2 are respectively provided with a raw material delivery pipe 35, and the raw material delivery pipe 35 is provided with a sixth regulating valve 36. The liquid refined naphthalene recovery tank 12 is provided with a liquid refined naphthalene delivery pipe 37 and a third liquid level sensor 40, and the liquid refined naphthalene delivery pipe 37 is provided with a seventh regulating valve 38 and a second booster pump 39.
[0022] The usage of this product is as follows: Figure 1 and Figure 2 As shown, the following steps are included:
[0023] S1. Add industrial naphthalene into the first reaction kettle 1 and the second reaction kettle 2.
[0024] S2, heat transfer oil is introduced into the heat transfer oil delivery main pipe 15. After entering the heat transfer oil delivery main pipe 15, the heat transfer oil is first fed back by the first temperature sensor 16 and then divided into two parts: the first part of the heat transfer oil is sent into the jacket of the first reactor 1 to perform heat exchange on the industrial naphthalene in the reactor body of the first reactor 1, and the flow rate of the first part of the heat transfer oil is adjusted according to the liquid level height of the industrial naphthalene fed back by the first liquid level sensor 24 on the first reactor 1; the second part of the heat transfer oil is sent into the jacket of the second reactor 2 to perform heat exchange on the industrial naphthalene in the reactor body of the second reactor 2, and the flow rate of the first part of the heat transfer oil is adjusted according to the liquid level height of the industrial naphthalene fed back by the first liquid level sensor 24 on the second reactor 2.
[0025] S3. According to the temperature parameters fed back by the second temperature sensor 23 installed on the heat transfer oil return branch 21 connected to the first reactor 1 and the temperature parameters fed back by the second temperature sensor 23 installed on the heat transfer oil return branch 21 connected to the second reactor 2, further adjust the opening of the first regulating valve 18 and the opening of the second regulating valve 22 corresponding to the first reactor 1 until the industrial naphthalene in the first reactor 1 is within the preset temperature range. It is also necessary to further adjust the opening of the first regulating valve 18 and the opening of the second regulating valve 22 corresponding to the second reactor 2 until the industrial naphthalene in the second reactor 2 is within the preset temperature range.
[0026] In step S3, when the industrial naphthalene in the first reactor 1 is within a preset temperature range, the industrial naphthalene in the first reactor 1 is in a boiling state to form a first naphthalene vapor, wherein the first naphthalene vapor includes a large amount of naphthalene and a small amount of heavy component impurities; when the industrial naphthalene in the second reactor 2 is within a preset temperature range, the industrial naphthalene in the second reactor 2 is below the boiling point of pure naphthalene.
[0027] S4, close the first regulating valve 18 and the second regulating valve 22 corresponding to the second reactor 2; at the same time, the aeration pipe 3 installed on the second reactor 2 receives the first naphthalene steam transported outward from the first reactor 1, and transports the first naphthalene steam to below the liquid level of the industrial naphthalene in the second reactor 2. After the first naphthalene steam enters the liquid level of the industrial naphthalene in the second reactor 2, the first naphthalene steam and the industrial naphthalene in the second reactor 2 are heat exchanged, the heavy components in the first naphthalene steam undergo phase change and generate phase change heat, and the heavy components in the first naphthalene steam are liquefied and mixed in the industrial naphthalene in the second reactor 2; and the naphthalene components in the industrial naphthalene in the second reactor 2 receive the phase change heat and are vaporized and combined to form the second naphthalene steam and are transported to the distillation tower through the second crude naphthalene steam delivery pipe 9 to complete rectification, and the heavy components contained in the second naphthalene steam and part of the naphthalene components are liquefied and mixed in the industrial naphthalene in the second reactor 2. The reflux liquid is formed by the reflux gas of the first reactor 1 and the reflux liquid of the first reactor 1. The reflux liquid is formed by the reflux gas of the first reactor 1 and the reflux liquid of the second reactor 1 is formed by the reflux gas of the first reactor 1. The reflux liquid is formed by the reflux gas of the first reactor 1 and the reflux liquid of the second reactor 1 is formed by the reflux gas of the first reactor 1. The reflux liquid is formed by the reflux gas of the first reactor 1 and the reflux liquid of the first reactor 1 is formed by the reflux gas of the first reactor 1 and the reflux liquid of the first reactor 1 is formed by the reflux gas of the first reactor 1. The reflux liquid is formed by the reflux gas of the first reactor 1 and the reflux liquid of the first reactor 1 is formed by the reflux gas of the first reactor 1 and the reflux liquid of the first reactor 1 is formed by the reflux gas of the first reactor 1 and the reflux liquid of the first reactor 1 is formed by the reflux gas of the first reactor 1
[0028] S5. When the component parameters of the residual liquid after evaporation in the first reactor 1 fed back by the online chromatograph 32 are within the preset range, the heating of the first reactor 1 should be stopped immediately, and the residual liquid in the first reactor 1 should be discharged to the designated area through the coarse slag discharge pipe 33 to be properly managed as hazardous waste.
[0029] S6. After the first reactor 1 is emptied of residual liquid, the industrial naphthalene in the second reactor 2 is delivered to the first reactor 1 through the crude naphthalene delivery pipe 25, thereby completing the material preparation of the first reactor 1 before the next industrial naphthalene distillation and heating; after the industrial naphthalene in the second reactor 2 is delivered, the industrial naphthalene is delivered to the second reactor 2 again through the raw material delivery pipe 35 connected to the second reactor 2, thereby completing the material preparation of the second reactor 2 before the next industrial naphthalene distillation and heating.
[0030] S7, the liquid refined naphthalene recovery tank 12 continuously receives the liquid refined naphthalene liquefied by the condenser 11. When the phthalic anhydride production system needs naphthalene vapor, the second booster pump 39 is turned on to transport the liquid refined naphthalene to the corresponding vaporization equipment through the liquid refined naphthalene delivery pipe 37, and the refined naphthalene vapor is continuously transported to the phthalic anhydride production system.
[0031] It should be noted that the purpose of heating the second reactor 2 with the corresponding heat-conducting oil in step S1 is to prevent the technical problem that the industrial naphthalene temperature in the second reactor 2 is too low, and the industrial naphthalene in the second reactor 2 is excessively liquefied during the heat exchange process between the first naphthalene steam delivered by the first reactor 1 and the industrial naphthalene in the second reactor 2. In the above steps, the liquid medium in the second reactor 2 should be delivered to the first reactor 1 in time using the crude naphthalene delivery pipe 25 according to the liquid level parameter fed back by the first liquid level sensor 24 installed on the second reactor 2, so as to keep the liquid level parameter fed back by the first liquid level sensor 24 installed on the second reactor 2 always within the preset range.
[0032] Through this embodiment, the naphthalene vapor delivered from the first reactor 1 is received by the second reactor 2, so that the naphthalene vapor and the industrial naphthalene in the second reactor 2 are heat exchanged. The physical property that the boiling point of the heavy components in the naphthalene vapor is higher than that of pure naphthalene is utilized to realize a large amount of liquefaction of the heavy components in the naphthalene vapor delivered by the first reactor 1, thereby achieving the technical purpose of reducing the heavy components in the tar naphthalene vapor entering the distillation tower, and reducing the probability of the distillation tower being blocked. The distillation tower described in this product includes a tower body 6 and a first baffle 7 and a second baffle 8 alternately arranged from top to bottom in the tower body 6. The heat exchange path is increased by the first baffle 7 and the second baffle 8. Compared with a distillation tower in the form of a packing layer, it is less likely to be blocked during the distillation of the naphthalene vapor.
[0033] The embodiments described above are only preferred embodiments of the present invention and are not intended to limit the scope of implementation of the present invention. Therefore, any equivalent changes or modifications made based on the structures, features and principles described in the patent scope of the present invention should be included in the patent application scope of the present invention.
Claims
1. A rectification device for industrial naphthalene of naphthalene-based phthalic anhydride, characterized in that: The invention comprises a first reactor (1), a second reactor (2) and a distillation tower, wherein the second reactor (2) is provided with an aeration pipe (3), the gas phase outlet end of the first reactor (1) is connected to the gas inlet end of the aeration pipe (3), the distillation tower comprises a tower body (6) and a first baffle (7) and a second baffle (8) arranged alternately from top to bottom in the tower body (6), the tower body (6) below the first baffle (7) and the second baffle (8) is connected to the gas phase outlet end of the second reactor (2), the bottom end of the tower body (6) is connected to the liquid outlet end of the first reactor (1), and the bottom end of the tower body (6) is connected to the liquid outlet end of the first reactor (1). The inlet ends of the tower bodies (6) are connected to each other, the inlet end of a refined naphthalene vapor delivery pipe (10) is arranged on the top of the tower body (6), the inlet end of a heat source channel of a condenser (11) is arranged on the outlet end of the refined naphthalene vapor delivery pipe (10), the outlet end of the heat source channel of the condenser (11) is connected to a liquid refined naphthalene recovery tank (12), a wire mesh agglomerator (13) is arranged in the inner cavity of the liquid refined naphthalene recovery tank (12) above the connection between the liquid refined naphthalene recovery tank (12) and the condenser (11), and the tail gas delivery pipe (14) is connected to the liquid refined naphthalene recovery tank (12) above the wire mesh agglomerator (13).
2. The rectifying unit of industrial naphthalene of naphthalene-based phthalic anhydride according to claim 1, wherein: The invention also comprises a heat transfer oil delivery main pipe (15), on which a first temperature sensor (16) is arranged. The first reactor (1) and the second reactor (2) both comprise a reactor body, a stirring device arranged on the reactor body, and a jacket arranged on the reactor body. The jacket of the first reactor (1) and the heat transfer oil delivery main pipe (15) are connected to each other, as are the jacket of the second reactor (2) and the heat transfer oil delivery main pipe (15). The heat transfer oil delivery branch pipe (17) is provided with a first regulating valve (18) and a liquid flow sensor (19).
3. The rectifying unit of industrial naphthalene of naphthalene-based phthalic anhydride according to claim 2, wherein: It also comprises a heat transfer oil return main pipe (20), wherein the heat transfer oil return main pipe (20) and the jacket of the first reaction kettle (1) and the jacket of the second reaction kettle (2) are respectively connected via a heat transfer oil return branch pipe (21), and a second regulating valve (22) and a second temperature sensor (23) are provided on the heat transfer oil delivery branch pipe (17).
4. The rectifying unit of industrial naphthalene of naphthalene-based phthalic anhydride according to claim 2, wherein: The first reactor (1) and the second reactor (2) are each provided with a first liquid level sensor (24); the bottom end of the reactor body of the first reactor (1) and the top end of the reactor body of the second reactor (2) are connected via a crude naphthalene delivery pipe (25); and the crude naphthalene delivery pipe (25) is provided with a first booster pump (26) and a third regulating valve (27).
5. The rectifying device of industrial naphthalene of naphthalene-based phthalic anhydride according to claim 4, characterized in that: A second liquid level sensor (28) is provided on the tower body (6) below the first baffle plate (7) and the second baffle plate (8); the bottom end of the tower body (6) and the top end of the reactor body of the first reactor (1) are connected via a reflux liquid delivery pipe (29); a second one-way valve (30) and a fourth regulating valve (31) are provided on the reflux liquid delivery pipe (29); an online chromatograph (32) is provided on the reactor body of the first reactor (1); a coarse slag discharge pipe (33) is provided on the bottom end of the reactor body of the first reactor (1); and a fifth regulating valve (34) is provided on the coarse slag discharge pipe (33).
6. The rectifying device for industrial naphthalene of naphthalene-based phthalic anhydride according to claim 1, characterized in that: The first reaction kettle (1) and the second reaction kettle (2) are each provided with a raw material delivery pipe (35), and the raw material delivery pipe (35) is provided with a sixth regulating valve (36). The liquid refined naphthalene recovery tank (12) is provided with a liquid refined naphthalene delivery pipe (37), and the liquid refined naphthalene delivery pipe (37) is provided with a seventh regulating valve (38) and a second booster pump (39).