Hydrogenation reactor and reaction device for hydrogenation of nitrobenzene to aniline

Abstract

The application relates to a hydrogenation reactor and a reaction device for preparing aniline by hydrogenating nitrobenzene, wherein the hydrogenation reactor comprises a reactor shell, a raw material inlet arranged at a first end of the reactor shell, a gas-phase product outlet arranged at a second end of the reactor shell, a plurality of reaction sections arranged in the reactor shell from the first end to the second end, a plurality of reaction tubes filled with catalysts arranged in the reaction sections, and the number of the reaction tubes arranged in the reaction sections gradually increases from the first end to the second end of the reactor shell, and the length-diameter ratio of the reaction tubes gradually decreases. The application can make the materials in the reactor shell quickly remove the heat released in the reaction, greatly reduce the probability of the occurrence of a 'hot spot' temperature in the reactor shell, make the reaction as balanced as possible in the hydrogenation reactor, avoid local overheating, and thus avoid the problems of the reduction of catalyst activity and even deactivation caused by local overheating.

Description

Technical Field

[0001] This application relates to the field of chemical equipment technology, and in particular to a hydrogenation reactor and a reaction apparatus for the hydrogenation of nitrobenzene to produce aniline. Background Technology

[0002] Aniline is a key basic chemical raw material, widely used in many industries such as dyes, pharmaceuticals, rubber additives, and pesticides, with a huge market demand. The hydrogenation of nitrobenzene to aniline is the mainstream industrial method for producing aniline. The hydrogenation reaction of nitrobenzene to aniline involves the release of a large amount of heat, creating a temperature gradient within the reactor. Hot spots can form locally, especially in the upper and middle sections of a fixed-bed reactor, leading to reduced catalyst activity or even deactivation.

[0003] Existing technologies typically eliminate hot spots by reducing the diameter of the reaction tubes, but this can easily lead to untimely heat exchange, resulting in localized overheating at the thicker tubes. If the diameter of the reaction tubes remains unchanged, there is an upper limit to the temperature control. In this case, overcoming the uneven temperature distribution in the reactor bed relies on the heat transfer effect between the tube side and the shell side to eliminate localized hot spots.

[0004] Existing technologies employ a sleeve structure for the reaction tube, filling the gap between the sleeves to form a catalyst bed. The cooling medium flows simultaneously through both the inner tube side and the reactor shell side, thereby increasing the heat exchange area and shortening the heat transfer path, resulting in a more uniform reaction temperature. However, this structure is difficult to manufacture, and the loading or replacement of catalyst is complex, affecting the effective catalyst loading. Another existing technology uses inert particles to dilute the catalyst in stages within the catalyst bed, thereby controlling catalyst activity and reaction rate to eliminate hot spots. However, this structure increases the height of the catalyst bed, reducing production capacity. Furthermore, the addition of inert particles leads to inconsistencies in the physical structure and chemical properties of the entire catalyst bed, resulting in significant discontinuities and instabilities in mass and heat transfer.

[0005] Existing technologies often configure the reaction tubes into upper, middle, and lower sections, with the diameters of the three sections gradually increasing from top to bottom. Each section is filled with a different dosage of catalyst to ensure consistency in the physical structure and chemical properties of the catalyst bed. This results in a non-linear distribution of reaction exothermics and bed temperature within the tube reactor, ultimately achieving uniform bed temperature. However, increasing the tube diameter can affect the heat exchange between the tube side and the shell side. "Hot spots" are prone to appear in the lower section of the tubes, leading to reduced catalyst activity or even deactivation. Utility Model Content

[0006] Therefore, it is necessary to provide a hydrogenation reactor and a reaction apparatus for the hydrogenation of nitrobenzene to aniline, in order to solve the problems that local overheating can easily occur in the reactor, resulting in reduced catalyst activity or even deactivation.

[0007] This application provides a hydrogenation reactor, comprising: a reactor shell; a raw material inlet is provided at a first end of the reactor shell, and a gaseous product outlet is provided at a second end of the reactor shell; multiple reaction sections are provided inside the reactor shell from the first end to the second end; multiple reaction tubes filled with catalyst are provided in the reaction sections; from the first end to the second end of the reactor shell, the number of reaction tubes provided in the reaction sections gradually increases, and the length-to-diameter ratio of the reaction tubes gradually decreases.

[0008] In one embodiment, the reaction tube in each reaction section is connected to the inner wall of the reactor shell via a first plate on the side facing the first end of the reactor shell; a grid plate is provided on the side of the reaction tube facing the second end of the reactor shell to prevent the catalyst from falling off.

[0009] In one embodiment, a gas distributor is provided inside the first end of the reactor shell; the raw material inlet is connected to the gas distributor.

[0010] In one embodiment, the reaction section includes a first reaction section, a second reaction section, and a third reaction section arranged sequentially from the first end to the second end; the number of reaction tubes arranged in the first reaction section is n1, the number of reaction tubes arranged in the second reaction section is n2, and the number of reaction tubes arranged in the third reaction section is n3, where n3>n2>n1, and n1≥2.

[0011] In one embodiment, the length-to-diameter ratio of the reaction tubes in the first reaction section is z1, the length-to-diameter ratio of the reaction tubes in the second reaction section is z2, and the length-to-diameter ratio of the reaction tubes in the third reaction section is z3, where z1>z2>z3; the length-to-diameter ratio z1 of the reaction tubes in the first reaction section is 10:1 to 20:1; the length-to-diameter ratio z2 of the reaction tubes in the second reaction section is 7:1 to 15:1; and the length-to-diameter ratio z3 of the reaction tubes in the third reaction section is 5:1 to 10:1.

[0012] In one embodiment, the length of the reaction tube disposed in the first reaction section is L1, the length of the reaction tube disposed in the second reaction section is L2, and the length of the reaction tube disposed in the third reaction section is L3, where L1>L2>L3.

[0013] In one embodiment, the outer diameter of the reactor shell is 1000mm~1500mm; and / or, the reaction tube is a heat exchange finned tube, copper tube or stainless steel tube.

[0014] In one embodiment, each of the reaction sections is provided with a heat exchange medium inlet and a heat exchange medium outlet for external heat exchange.

[0015] In one embodiment, the reactor shell is further provided with a pressure gauge port for installing a pressure gauge; each of the reaction sections is provided with a thermometer port for installing a thermometer on the side facing the second end of the reactor shell.

[0016] This application also provides a reaction apparatus for the hydrogenation of nitrobenzene to aniline, including the aforementioned hydrogenation reactor; further comprising: a gas mixer, a steam generator, and a product condenser; the hydrogenation reactor is further provided with a heat exchange medium inlet and a heat exchange medium outlet; the gas mixer is provided with: a raw material gas inlet, a gaseous product inlet, and a mixed gas outlet; the steam generator includes: a steam boiler, a hot water pump, and a hot water flow regulating valve; the steam boiler is provided with: a water inlet, a hot water outlet, a hot water inlet, and a steam outlet; the hot water pump is provided with: a pump outlet and a pump inlet; the product condenser includes: a first heat exchanger and a second heat exchanger; the first heat exchanger is provided with: a first shell-side inlet, a first shell-side gaseous outlet, a first tube-side inlet, and a first tube-side outlet; the second heat exchanger is provided with: a second shell-side inlet, a second shell-side liquid outlet, a second tube-side inlet, and a second tube-side outlet; the raw material gas inlet of the gas mixer is connected to a raw material gas pipeline; the mixed gas outlet of the gas mixer is connected to the raw material inlet of the hydrogenation reactor; the gas... The phase product outlet is simultaneously connected to the gas phase product inlet of the gas mixer and the first shell-side inlet of the first heat exchanger; the first tube-side inlet of the first heat exchanger is connected to the nitrobenzene pipeline; the second tube-side inlet of the first heat exchanger is connected to the devaporization pipeline; the first shell-side gas phase outlet of the first heat exchanger is connected to the second tube-side inlet of the second heat exchanger; the second tube-side outlet of the second heat exchanger is connected to the product post-processing pipeline; the second shell-side inlet of the second heat exchanger is connected to the pure water pipeline; the second shell-side liquid phase outlet of the second heat exchanger is connected to the water supply port of the steam package; the hot water inlet of the steam package is connected to the heat exchange medium outlet of the hydrogenation reactor; the hot water outlet of the steam package is connected to the water pump inlet of the hot water pump; the water pump outlet of the hot water pump is connected to the heat exchange medium inlet of the hydrogenation reactor; a hot water flow regulating valve is provided on the connecting pipeline between the water pump outlet of the hot water pump and the heat exchange medium inlet of the hydrogenation reactor.

[0017] Compared with the prior art, the hydrogenation reactor and the reaction apparatus for producing aniline by hydrogenating nitrobenzene provided in this application, by increasing the number of reaction tubes and decreasing the length-to-diameter ratio of the reaction tubes from the first end to the second end of the reactor shell, allow for segmented reaction within the hydrogenation reactor. The feed concentration gradually decreases from the reaction section at the first end of the reactor shell to the reaction section at the second end, thus gradually reducing the reaction rate and the exothermic efficiency. This allows the material in the reactor shell to quickly remove the heat released by the reaction from the feed inlet to the gaseous product outlet, greatly reducing the probability of "hot spot" temperatures within the reactor shell. This makes the reaction as uniform as possible within the hydrogenation reactor, avoiding local overheating and thus preventing the problem of reduced catalyst activity or even deactivation caused by local overheating. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of a hydrogenation reactor according to an embodiment of this application;

[0020] Figure 2 This is a schematic diagram of a reaction apparatus for the hydrogenation of nitrobenzene to aniline according to an embodiment of this application.

[0021] Figure Descriptions: 1. Hydrogenation reactor; 11. Reactor shell; 11a. First end; 11b. Second end; 111. Feed inlet; 112. Gaseous product outlet; 113. First reaction section; 114. Second reaction section; 115. Third reaction section; 116. Reaction tube; 117. First plate; 118. Grid plate; 119. Gas distributor; 1110. Pressure gauge port; 1111. Thermometer port; 1112. Heat exchange medium inlet; 1113. Heat exchange medium outlet; 12. Pressure gauge; 13. Thermometer; 2. Gas mixer; 21. Feed gas inlet; 22. Gaseous product inlet; 23. Mixing... 3. Steam generator; 31. Steam drum; 311. Water inlet; 312. Hot water outlet; 313. Hot water inlet; 314. Steam outlet; 32. Hot water pump; 321. Pump outlet; 322. Pump inlet; 33. Hot water flow regulating valve; 4. Product condensation device; 41. First heat exchanger; 411. First shell-side inlet; 412. First shell-side gas phase outlet; 413. First tube-side inlet; 414. First tube-side outlet; 42. Second heat exchanger; 421. Second shell-side inlet; 422. Second shell-side liquid phase outlet; 423. Second tube-side inlet; 424. Second tube-side outlet. Detailed Implementation

[0022] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0023] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on the other component or there may be an intermediate component. When a component is considered to be "connected to" another component, it can be directly connected to the other component or there may be an intermediate component present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application's specification are for illustrative purposes only and do not represent the only possible implementation.

[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0025] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature and the second feature are in indirect contact through an intermediate medium. Furthermore, "above," "over," and "on top" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0026] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used in this application includes any and all combinations of one or more of the associated listed items.

[0027] refer to Figure 1This application provides a hydrogenation reactor, including a reactor shell 11; a raw material inlet 111 is provided at a first end 11a of the reactor shell 11, and a gaseous product outlet 112 is provided at a second end 11b of the reactor shell 11; multiple reaction sections are provided inside the reactor shell 11 from the first end 11a to the second end 11b; multiple reaction tubes 116 filled with catalyst are provided in the reaction sections; from the first end 11a to the second end 11b of the reactor shell 11, the number of reaction tubes 116 provided in the reaction sections gradually increases, and the length-to-diameter ratio of the reaction tubes 116 gradually decreases. The aspect ratio refers to the ratio of the length of the reaction tube 116 to its nominal diameter. Since the raw material concentration at the feed inlet 111 of the reactor shell 11 is higher than in other areas, by sequentially increasing the number of reaction tubes and decreasing their aspect ratios from the first to the second end of the reactor shell, the conversion rate of the raw material at the first end 11a of the reactor shell 11 is reduced. This also allows the material inside the reactor shell to quickly remove the heat released by the reaction, significantly reducing the probability of "hot spots" within the reactor shell. This ensures a more balanced reaction within the hydrogenation reactor, avoiding localized overheating and thus preventing the reduction or even deactivation of the catalyst caused by localized overheating. In actual production, the number and length of the reaction tubes 116 in each reaction section can be adjusted according to production needs, and a suitable aspect ratio can be selected.

[0028] Furthermore, the reaction tube 116 in each reaction section is connected to the inner wall of the reactor shell 11 via a first plate 117 on the side facing the first end 11a of the reactor shell 11; a grid plate 118 is provided on the side of the reaction tube 116 facing the second end 11b of the reactor shell 11 to prevent catalyst from falling off. More specifically, the aperture of the grid plate 118 is smaller than the catalyst particle size, which can effectively prevent catalyst particles from falling off the grid plate 118, while allowing the raw material gas to enter the reaction tube 116 from the grid plate 118 to react.

[0029] Furthermore, in one embodiment, a gas distributor 119 is provided in the first end 11a of the reactor shell 11; the raw material inlet 111 is connected to the gas distributor 119, so that the raw material gas is uniformly distributed in the cross section of the hydrogenation reactor 1.

[0030] Further, in one embodiment, the reaction section includes a first reaction section 113, a second reaction section 114, and a third reaction section 115 arranged sequentially from the first end 11a to the second end 11b; the number of reaction tubes 116 arranged in the first reaction section 113 is n1, the number of reaction tubes 116 arranged in the second reaction section 114 is n2, and the number of reaction tubes 116 arranged in the third reaction section 115 is n3, where n3>n2>n1, and n1≥2. Since the raw material gas concentration is the highest at the raw material inlet 111, the reaction is the most intense, and the most heat is released, making it most prone to local overheating, the conversion rate of the raw material at the first end 11a of the reactor shell 11 is reduced by decreasing the number of reaction tubes 116 in the first reaction section 113, while gradually increasing the number of reaction tubes 116 in the second reaction section 114 and the third reaction section 115, the reaction is gradually guided to other areas of the reactor shell 11, expanding the reaction area and making the reaction in each reaction section more balanced, thus avoiding local overheating of the reactor shell 11 as much as possible.

[0031] Furthermore, the aspect ratio of the reaction tubes in the first reaction section 113 is z1, the aspect ratio of the reaction tubes in the second reaction section 114 is z2, and the aspect ratio of the reaction tubes in the third reaction section 115 is z3, where z1>z2>z3. The aspect ratio of the reaction tubes 116 in the first reaction section 113 is z1 of 10:1 to 20:1; the aspect ratio of the reaction tubes 116 in the second reaction section 114 is z2 of 7:1 to 15:1; and the aspect ratio of the reaction tubes 116 in the third reaction section 115 is z3 of 5:1 to 10:1. By adjusting the aspect ratio of the reaction tubes 116 in each reaction section, the reaction can be evenly distributed in each reaction section, effectively solving the problem of large temperature gradients within the hydrogenation reactor 1, reducing the possibility of local overheating, especially avoiding local overheating at the feed inlet 111, significantly improving reaction selectivity, and making the process operation safer and more economical.

[0032] Furthermore, the length of the reaction tube 116 in the first reaction section 113 is L1, the length of the reaction tube 116 in the second reaction section 114 is L2, and the length of the reaction tube 116 in the third reaction section 115 is L3, where L1>L2>L3. Since the raw material concentration in the first reaction section is greater than that in the second reaction section, the reaction in the first reaction section will be more vigorous than the reaction in the second reaction section. Therefore, for better heat dissipation, a longer and thinner reaction tube is selected for the first reaction section compared to the second reaction section. That is, the length of the reaction tube 116 in the first reaction section 113, the second reaction section 114, and the third reaction section 115 decreases sequentially, thereby shortening the heat transfer distance inside the reaction tube, accelerating the heat transfer rate, avoiding the probability of local "hot spot" temperatures, and also preventing the reaction from concentrating in the first reaction section 113 and the second reaction section 114, making the reaction in the three reaction sections more balanced and avoiding local overheating.

[0033] The outer diameter of the reactor shell 11 is 1000mm~1500mm, and the outer diameter of the reactor shell 11 can be adjusted according to the actual production output.

[0034] Furthermore, the reaction tube 116 is a heat exchange finned tube, copper tube, or stainless steel tube, preferably a heat exchange finned tube. Since the reaction process releases a large amount of heat, heat exchange finned tubes, copper tubes, or stainless steel tubes can better enhance the heat exchange efficiency. In particular, heat exchange finned tubes greatly increase the heat exchange surface area and have better heat exchange efficiency.

[0035] Furthermore, each reaction section is equipped with a heat exchange medium inlet 1112 and a heat exchange medium outlet 1113 for external heat exchange. This allows for independent temperature control of each reaction section, resulting in more flexible reaction control. The temperature of each reaction section can be controlled by adjusting the flow rate of the medium in the heat exchange pipes. The heat exchange medium can be steam or oil; this application does not impose any limitations on this.

[0036] Furthermore, the reactor shell 11 is also provided with a pressure gauge port 1110 for installing a pressure gauge 12, so that the pressure value inside the reactor shell 11 can be obtained through the pressure gauge port 1110.

[0037] Each reaction section is provided with a thermometer port 1111 for mounting a thermometer 13 on the second end 11b facing the reactor shell 11. The temperature of the gaseous products after the reaction in each reaction section is measured by the thermometer, thereby enabling individual temperature monitoring of each reaction section.

[0038] To verify the technical effect of the technical solution shown in this embodiment, multiple embodiments and comparative examples were set up for comparative experiments.

[0039] In Example 1, the reactor shell 11 has a diameter of 1000 mm. The first reaction section 113 has 5 reaction tubes 116, each 1000 mm long and DN50 in diameter. The second reaction section 114 has 10 reaction tubes 116, each 750 mm long and DN50 in diameter. The third reaction section 115 has 15 reaction tubes 116, each 500 mm long and DN50 in diameter.

[0040] The reaction conditions in hydrogenation reactor 1 are as follows: temperature: 230℃~240℃, gas pressure: 0.45MPa, H2 / nitrobenzene (mol) = 25, gaseous product / feed gas (mass ratio) = 0.3.

[0041] In Example 2, the reactor shell 11 has a diameter of 1200 mm. The first reaction section 113 has 10 reaction tubes 116, each with a length of 800 mm and a diameter of DN50. The second reaction section 114 has 15 reaction tubes 116, each with a length of 600 mm and a diameter of DN50. The third reaction section 115 has 20 reaction tubes 116, each with a length of 400 mm and a diameter of DN50.

[0042] The reaction conditions in hydrogenation reactor 1 are as follows: temperature: 230℃~240℃, gas pressure: 0.45MPa, H2 / nitrobenzene (mol) = 25, gaseous product / feed gas (mass ratio) = 0.25.

[0043] In Example 3, the reactor shell 11 has a diameter of 1500 mm, the first reaction section 113 has 15 reaction tubes 116 with a length of 500 mm and a diameter of DN50, the second reaction section 114 has 20 reaction tubes 116 with a length of 400 mm and a diameter of DN50, and the third reaction section 115 has 25 reaction tubes 116 with a length of 300 mm and a diameter of DN50.

[0044] The reaction conditions in hydrogenation reactor 1 are as follows: temperature: 230℃~240℃, gas pressure: 0.45MPa, H2 / nitrobenzene (mol) = 25, gaseous product / feed gas (mass ratio) = 0.2.

[0045] In Comparative Example 1, the reactor shell 11 has a diameter of 1200 mm. The first reaction section 113 has 15 reaction tubes 116, each with a length of 800 mm and a diameter of DN32. The second reaction section 114 has 15 reaction tubes 116, each with a length of 600 mm and a diameter of DN32. The third reaction section 115 has 15 reaction tubes 116, each with a length of 400 mm and a diameter of DN32.

[0046] The reaction conditions in hydrogenation reactor 1 are as follows: temperature: 230℃~240℃, gas pressure: 0.45MPa, H2 / nitrobenzene (mol) = 25, gaseous product / feed gas (mass ratio) = 0.25.

[0047] In Comparative Example 2, the reactor shell 11 has a diameter of 1200 mm. The first reaction section 113 has 10 reaction tubes 116, each 800 mm long and with a diameter of DN50. The second reaction section 114 has 15 reaction tubes 116, each 800 mm long and with a diameter of DN50. The third reaction section 115 has 20 reaction tubes 116, each 800 mm long and with a diameter of DN50.

[0048] The reaction conditions in hydrogenation reactor 1 are as follows: temperature: 230℃~240℃, gas pressure: 0.45MPa, H2 / nitrobenzene (mol) = 25, gaseous product / feed gas (mass ratio) = 0.25.

[0049] The reaction effects of Examples 1-3 and Comparative Examples 1-2 are shown in Table 1.

[0050] Table 1

[0051]

[0052] refer to Figure 2 This embodiment also provides a reaction apparatus for the hydrogenation of nitrobenzene to produce aniline, including: a hydrogenation reactor 1, a gas mixer 2, a steam generator 3, and a product condenser 4.

[0053] The hydrogenation reactor 1 is provided with a feed inlet 111, a gaseous product outlet 112, a heat exchange medium inlet 1112, and a heat exchange medium outlet 1113. The gas mixer 2 is provided with a feed gas inlet 21, a gaseous product inlet 22, and a mixed gas outlet 23. The steam generator 3 includes a steam boiler 31, a hot water pump 32, and a hot water flow regulating valve 33. The steam boiler 31 is provided with a water inlet 311, a hot water outlet 312, a hot water inlet 313, and a steam outlet 314. The hot water inlet 313 of the steam boiler 31 is connected to the heat exchange medium outlet 1113 of the hydrogenation reactor 1. The hot water pump 32 is provided with a pump outlet 321 and a pump inlet 322. The product condensation device 4 includes a first heat exchanger 41 and a second heat exchanger 42. The first heat exchanger 41 is provided with a first shell-side inlet 411, a first shell-side gas phase outlet 412, a first tube-side inlet 413, and a first tube-side outlet 414. The second heat exchanger 42 is provided with a second shell-side inlet 421, a second shell-side liquid phase outlet 422, a second tube-side inlet 423, and a second tube-side outlet 424. The feed gas inlet 21 of the gas mixer 2 is connected to a feed gas pipeline, and the mixed gas outlet 23 of the gas mixer 2 is connected to the feed inlet 111 of the hydrogenation reactor 1. The gas phase product outlet 112 of the hydrogenation reactor 1 is simultaneously connected to the gas phase product inlet 22 of the gas mixer 2 and the first shell-side inlet 411 of the first heat exchanger 41.

[0054] The first shell-side gas phase outlet 412 of the first heat exchanger 41 is connected to the second tube-side inlet 423 of the second heat exchanger 42. The first tube-side inlet 413 of the first heat exchanger 41 is connected to a nitrobenzene pipeline. The second tube-side inlet 423 of the first heat exchanger 41 is connected to a devaporization pipeline. The second tube-side outlet 424 of the second heat exchanger 42 is connected to a product post-processing pipeline. The second shell-side inlet 421 of the second heat exchanger 42 is connected to a pure water pipeline. The second shell-side liquid phase outlet 422 of the second heat exchanger 42 is connected to the water supply inlet 311 of the steam drum 31. The hot water outlet 312 of the steam package 31 is connected to the water pump inlet 322 of the hot water pump 32, the hot water inlet 313 of the steam package 31 is connected to the heat exchange medium outlet 1113 of the hydrogenation reactor 1, and the water pump outlet 321 of the hot water pump 32 is connected to the heat exchange medium inlet 1112 of the hydrogenation reactor 1. A hot water flow regulating valve 33 is installed on the connecting pipeline between the water pump outlet 321 of the hot water pump 32 and the heat exchange medium inlet 1112 of the hydrogenation reactor 1. The hot water flow regulating valve 33 adjusts the flow rate according to the temperature measured by the thermometer 13.

[0055] The raw material gas flows in from the raw material gas inlet 21 of the gas mixer 2. After being fully mixed in the gas mixer 2, it enters the hydrogenation reactor 1 from the raw material inlet 111. After the reaction is completed, the gaseous product flows out from the gaseous product outlet 112 of the hydrogenation reactor 1. Part of it enters the gas mixer 2 through the gaseous product inlet 22 of the gas mixer 2 to mix with the raw material gas, and the other part enters the first heat exchanger 41 from the first shell-side inlet 411. Since the hydrogenation reaction of nitrobenzene releases a large amount of heat, the gaseous product after the reaction is completed still has residual heat, so the raw material can be preheated. The first tube-side inlet 413 of the first heat exchanger 41 is connected to the nitrobenzene pipeline. The gaseous product after the reaction is completed undergoes the first round of heat exchange in the first heat exchanger 41, and then enters the second heat exchanger 42. After the nitrobenzene is preheated, it flows out from the first tube-side outlet 414 of the first heat exchanger 41 and is vaporized. The gaseous product enters the second heat exchanger 42 through the second tube inlet 423, and pure water enters the second heat exchanger 42 through the second shell inlet 421. The gaseous product and pure water undergo a second round of heat exchange within the second heat exchanger 42. After cooling, the gaseous product flows out through the second tube outlet 424 of the second heat exchanger 42 and undergoes post-processing. After heat exchange, the pure water flows out through the second shell liquid outlet 422 of the second heat exchanger 42 and enters the steam package 31 through the water inlet 311. The pure water in the steam package 31 is pumped into the heat exchange inlet of the hydrogenation reactor 1 by the hot water pump 32. After absorbing a large amount of heat released during the reaction in the hydrogenation reactor 1, the pure water flows out through the heat exchange outlet of the hydrogenation reactor 1 and returns to the steam package 31 through the hot water inlet 313. The steam generated in the steam package 31 is discharged through the steam outlet 314 and can be used for other purposes.

[0056] In order to control the temperature of each reaction section, each reaction section is equipped with a separate heat exchange medium inlet 1112 and heat exchange medium outlet 1113, as well as a thermometer port 1111. After the thermometer 13 collects the temperature data from the thermometer port 1111, it adjusts the hot water flow regulating valve 33, thereby controlling the temperature of each reaction section individually.

[0057] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0058] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. Therefore, the patent protection scope of this application should be determined by the appended claims.

Claims

1. A hydrogenation reactor characterized by, include: Reactor shell (11); The reactor shell (11) has a raw material inlet (111) at its first end (11a) and a gaseous product outlet (112) at its second end (11b). The reactor shell (11) has multiple reaction sections arranged from the first end (11a) to the second end (11b) inside; The reaction section is equipped with multiple reaction tubes (116) filled with catalyst. From the first end (11a) to the second end (11b) of the reactor shell (11), the number of reaction tubes (116) arranged in the reaction section gradually increases, and the length-to-diameter ratio of the reaction tubes (116) gradually decreases.

2. The hydrogenation reactor according to claim 1, characterized in that, The reaction tube (116) in each reaction section is connected to the inner wall of the reactor shell (11) via a first plate (117) on the side facing the first end (11a) of the reactor shell (11). The reaction tube (116) is provided with a grid plate (118) on the side facing the second end (11b) of the reactor shell (11) to prevent the catalyst from falling off.

3. The hydrogenation reactor according to claim 1, characterized in that, A gas distributor (119) is provided inside the first end (11a) of the reactor shell (11). The raw material inlet (111) is connected to the gas distributor (119).

4. The hydrogenation reactor according to claim 1, characterized in that, The reaction section includes a first reaction section (113), a second reaction section (114) and a third reaction section (115) arranged sequentially from the first end (11a) to the second end (11b). The number of reaction tubes (116) set in the first reaction section (113) is n1, the number of reaction tubes (116) set in the second reaction section (114) is n2, and the number of reaction tubes (116) set in the third reaction section (115) is n3, n3>n2>n1, and n1≥2.

5. The hydrogenation reactor according to claim 4, characterized in that, The length-to-diameter ratio of the reaction tube (116) set in the first reaction section (113) is z1, the length-to-diameter ratio of the reaction tube (116) set in the second reaction section (114) is z2, and the length-to-diameter ratio of the reaction tube (116) set in the third reaction section (115) is z3, where z1>z2>z3; The length-to-diameter ratio z1 of the reaction tube (116) installed in the first reaction section (113) is 10:1 to 20:1; The length-to-diameter ratio z2 of the reaction tube (116) installed in the second reaction section (114) is 7:1 to 15:1; The length-to-diameter ratio z3 of the reaction tube (116) set in the third reaction section (115) is 5:1 to 10:

1.

6. The hydrogenation reactor of claim 5, wherein, The length of the reaction tube (116) set in the first reaction section (113) is L1, the length of the reaction tube (116) set in the second reaction section (114) is L2, and the length of the reaction tube (116) set in the third reaction section (115) is L3, where L1>L2>L3.

7. The hydrogenation reactor of claim 1, wherein, The outer diameter of the reactor shell (11) is 1000mm~1500mm; And / or, the reaction tube (116) is a heat exchange finned tube, a copper tube or a stainless steel tube.

8. The hydrogenation reactor of claim 1, wherein, Each of the reaction sections is provided with a heat exchange medium inlet (1112) and a heat exchange medium outlet (1113) for external heat exchange.

9. The hydrogenation reactor of claim 1, wherein, The reactor shell (11) is also provided with a pressure gauge port (1110) for installing a pressure gauge (12). Each of the reaction sections is provided with a thermometer port (1111) for mounting a thermometer (13) on the side facing the second end (11b) of the reactor shell (11).

10. A reaction apparatus for the hydrogenation of nitrobenzene to aniline, characterized by Includes the hydrogenation reactor as described in any one of claims 1-9; It also includes: a gas mixer (2), a steam generator (3) and a product condenser (4); The hydrogenation reactor (1) is also provided with a heat exchange medium inlet (1112) and a heat exchange medium outlet (1113). The gas mixer (2) is provided with: a raw material gas inlet (21), a gaseous product inlet (22) and a mixed gas outlet (23). The steam generating device (3) includes: a steam package (31), a hot water pump (32), and a hot water flow regulating valve (33); The steam package (31) is provided with: a water inlet (311), a hot water outlet (312), a hot water inlet (313), and a steam outlet (314). The hot water pump (32) is provided with: a pump outlet (321) and a pump inlet (322); The product condensation device (4) includes: a first heat exchanger (41) and a second heat exchanger (42). The first heat exchanger (41) is provided with: a first shell-side inlet (411), a first shell-side gas phase outlet (412), a first tube-side inlet (413) and a first tube-side outlet (414). The second heat exchanger (42) is provided with: a second shell-side inlet (421), a second shell-side liquid phase outlet (422), a second tube-side inlet (423), and a second tube-side outlet (424). The raw material gas inlet (21) of the gas mixer (2) is connected to the raw material gas pipeline; The mixed gas outlet (23) of the gas mixer (2) is connected to the raw material inlet (111) of the hydrogenation reactor (1); The gaseous product outlet (112) of the hydrogenation reactor (1) is simultaneously connected to the gaseous product inlet (22) of the gas mixer (2) and the first shell-side inlet (411) of the first heat exchanger (41). The first tube inlet (413) of the first heat exchanger (41) is connected to the nitrobenzene pipe; The second tube inlet (423) of the first heat exchanger (41) is connected to the devaporization pipe; The first shell-side gas phase outlet (412) of the first heat exchanger (41) is connected to the second tube-side inlet (423) of the second heat exchanger (42); The second tube outlet (424) of the second heat exchanger (42) is connected to the product post-processing pipeline; The second shell-side inlet (421) of the second heat exchanger (42) is connected to a pure water pipeline; The second shell-side liquid phase outlet (422) of the second heat exchanger (42) is connected to the water inlet (311) of the steam package (31); The hot water inlet (313) of the steam package (31) is connected to the heat exchange medium outlet (1113) of the hydrogenation reactor (1); The hot water outlet (312) of the steam package (31) is connected to the water pump inlet (322) of the hot water pump (32); The water pump outlet (321) of the hot water pump (32) is connected to the heat exchange medium inlet (1112) of the hydrogenation reactor (1); A hot water flow regulating valve (33) is provided on the connecting pipeline between the water pump outlet (321) of the hot water pump (32) and the heat exchange medium inlet (1112) of the hydrogenation reactor (1).

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