Efficient tubular reactor and application thereof

Abstract

The invention discloses a high-efficiency tubular reactor and application, the high-efficiency tubular reactor comprises a reaction zone, a heat exchange zone and a separation zone which are integrally coupled, and the zones cooperate with each other. The reactor is simple in equipment structure, compact in equipment installation, low in energy consumption and high in equipment integration level, and in the application process, safety can be guaranteed, and meanwhile the technological operation is more flexible. The efficient tubular reactor can be applied to heat release reactions such as nitration reaction, alkylation reaction, chlorination reaction and diazotization reaction, the process is safer, the product quality is higher, and the efficient tubular reactor has wide application prospects.

Description

Technical Field

[0001] The present invention belongs to the field of chemical reaction engineering, and particularly relates to a high-efficiency tubular reactor and its application, especially a high-efficiency tubular reactor that can be used in reaction processes such as nitration reaction, alkylation reaction, chlorination reaction, and diazotization reaction. Background Art

[0002] The fine chemical industry occupies an important position in China's high-tech field. As a traditional industry in China, it occupies an extremely important position in the national economy. While the fine chemical industry is developing rapidly, safety accidents occur frequently. Analysis reports show that the lack of inherent safety design in the chemical process reaction is one of the major causes of accidents. Due to a series of excellent characteristics such as small volume, high efficiency, and inherent safety, tubular reactors have been widely used in the field of fine chemical synthesis industry.

[0003] Tubular reactors can be divided into two categories according to their shapes. One is the long-tube type tubular reactor with a tubular shape and a large length-diameter ratio. Its basic form is a relatively long pipeline, with a feed inlet at one end and a discharge outlet at the other end. The pipeline length is generally more than dozens of meters, some reach hundreds of meters, and some tubular reactors can be even longer. For example, the tube length of the tubular reactor for propylene dimerization is measured in kilometers. The other is the short-tube type tubular reactor, which can be called a shell-and-tube reactor. This kind of equipment is composed of multiple tubes and a shell side, and its structure is similar to that of a vertical fixed tube sheet heat exchanger. Special designed baffles are usually equipped inside the reactor to ensure the most effective fluid distribution, so as to obtain the best mass transfer and heat transfer effects. Some adopt the internal impinging stream method to enhance the stirring function and improve the reaction rate.

[0004] Chinese patent document CN205731274U with the publication number of an efficient reactor. This invention provides an efficient reactor with a simple and compact structure and high heat exchange efficiency. This reactor includes a heat exchange box, a cloth box, and a collection box. Tube sheets are provided at the upper and lower ends of the heat exchange box, and heat exchange tubes are fixed on the tube sheets. Catalysts are provided inside the heat exchange tubes. An annular clamping part is provided at the lower end of each heat exchange tube. A step is provided inside the clamping part, and a filter screen and an orifice plate are stacked on the step from top to bottom to prevent the loss of catalysts. In this efficient reactor, the liquid material descends from the cloth box in a film form into the heat exchange tubes, conducts heat transfer with the heat transfer medium, and the heated liquid material flows to the bottom of the heat exchange tubes to contact the catalyst for reaction. After the reaction is completed, the finished product flows out from the collection box. The overall structure is compact, energy-saving, and efficient, integrating heat exchange and reaction, which is equivalent to the combination of an existing heater and a reactor. This reactor belongs to a typical conventional shell-and-tube reactor, with a simple structure and easy operation control, and has good effects on conventional homogeneous fluid phase systems and fast reactions with active reaction properties. However, for processes with high mass transfer requirements, strict reaction temperature requirements, and complex reaction systems, its application effects cannot be guaranteed.

[0005] The Chinese patent document with the publication number CN118267963A discloses a nitration reactor that couples reaction, separation, and heat exchange. The reactor includes a reaction zone, a separation zone, and a heat exchange zone; the reaction zone includes a tubular reactor body, which is sequentially provided with an inlet heat exchanger, a mixing element, a reduced diameter structure, and an overflow outlet from bottom to top; the separation zone includes a separation zone housing, a rotary separation device, and an oleic acid separation chamber arranged coaxially; the heat exchange zone includes coiled pipes, and the coiled pipes are wound around the tubular reactor body. This invention document discloses the entire process method of raw material feeding, preheating, nitration reaction, and two-phase separation of the reaction system in the conventional nitration reaction process. It uses the heat source generated by the nitration reaction itself to heat the raw materials, effectively reducing the operating cost; it uses the mixing unit provided in the reactor body to carry out the nitration reaction, and after the reaction, with the help of the action of rotational centrifugal force and structured packing, the two phases of the reaction system are separated. In all chemical production processes, reaction synthesis is of utmost importance and is the core of production. The reaction method disclosed in this patent document only uses a mixing unit, and the specific description of the mixing unit is not detailed, so its reaction effect cannot be judged. In industrial production, it is still difficult to control violent exothermic reactions.

[0006] As is well known, in general exothermic reactions, as the reaction progresses, a huge amount of energy will be released during the reaction process. Especially in the middle stage of the reaction, the heat is more concentrated, resulting in a sudden increase in the temperature of the reaction system, as shown in the Figure 1 conventional chemical reaction temperature vs. time trend graph.

[0007] Those skilled in the art know that the chemical reaction temperature equilibrium point is an important influencing factor in the reaction process. Whether the temperature is too low or too high, and the operating point deviates from the thermal reaction equilibrium point, it will lead to the occurrence of side reactions and affect the quality of the synthesized product. If the operating temperature exceeds the standard and reaches the decomposition or imbalance temperature, even catastrophic consequences may occur. To ensure product quality, the reaction temperature must be precisely controlled to ensure the generation of the target product. As shown in the Figure 2 conventional chemical reaction energy release process stage partition diagram. According to the temperature rise characteristics of the reaction process, the reaction process is divided into three processes. The initial stage of the reaction is the energy startup stage, and the reaction temperature increases relatively gently in this stage. As the reaction progresses, a huge amount of reaction heat is instantaneously released, and the reaction temperature rises sharply. In the later stage of the reaction, the temperature change tends to be gentle temperature rise. The control of the reaction temperature in the Chinese patent with the publication number CN118267963A also belongs to the conventional heat exchange technology, and it is still difficult to control the reaction temperature in highly exothermic reaction processes such as nitration reaction, alkylation reaction, chlorination reaction, and diazotization reaction.

[0008] In view of the defects in the prior art, such as low reaction efficiency, relatively complex reaction equipment, and high power consumption, in reaction processes such as tubular reactors and those applied to nitration reactions, alkylation reactions, chlorination reactions, and diazotization reactions, the present invention provides a high-efficiency tube reactor and process. Starting from the core issues of chemical reactions - efficient mixing, precise heat exchange, and effective integration - it optimizes the mixing and dispersion of the reaction material flow system, achieving effects such as large volumetric flow rate, small backmixing, and no stirring dead corners. It can enable efficient transfer of the kinetic energy and mass of the material flow system, greatly improve the stirring efficiency, and reduce power consumption. And starting from the optimization of process conditions and safety in chemical reactions, it is flexible in operation and reduces safety risks. Summary of the Invention

[0009] In view of the defects in the prior art, such as low reaction efficiency, relatively complex reaction equipment, and high power consumption, in reaction processes such as tubular reactors and those applied to nitration reactions, alkylation reactions, chlorination reactions, and diazotization reactions, the present invention provides a high-efficiency tube reactor. This reactor highly integrates reaction, heat exchange, and separation. The high-efficiency tube reactor ensures the mass transfer of the reaction material flow. The independently arranged heat exchange area optimizes the reaction conditions while transferring heat, and has the advantages of high reaction efficiency, relatively simple reaction equipment, and low power consumption.

[0010] The first object of the present invention is to provide a high-efficiency tube reactor. This reactor highly integrates reaction, heat exchange, and separation. The high-efficiency tube reactor ensures the mass transfer of the reaction material flow. The independently arranged heat exchange area optimizes the reaction conditions while transferring heat.

[0011] The second object of the present invention is to provide an application of the high-efficiency tube reactor of the present invention in reaction processes with intense heat release, such as nitration reactions, alkylation reactions, chlorination reactions, and diazotization reactions.

[0012] To achieve the first object of the present invention, the following technical solutions are adopted:

[0013] A high-efficiency tube reactor includes a reaction zone, a heat exchange zone, and a separation zone that are integrally coupled. Each zone influences, depends on, and is related to each other.

[0014] The reaction zone includes a reactor main body. Inside the reactor main body, a stirrer and a transmission shaft are provided. The stirrer is connected to a drive motor through the transmission shaft. Multiple reactor tubes are arranged inside the reactor main body.

[0015] A reaction material flow inlet is provided at the bottom of the reactor main body, and reaction raw materials continuously enter the reactor main body from the reaction material flow inlet. At least one reaction material flow inlet is provided, or it can be set to 2 or 3.

[0016] The agitator is a key work component of the reactor. In the present invention, the agitator is in a combined form, including an emulsifying impeller and a propelling impeller; the emulsifying impeller is directly connected to the transmission shaft, and a porous structure is provided on the back of the emulsifying impeller;

[0017] The emulsifying impeller is directly connected to the transmission shaft, and the transmission shaft drives the emulsifying impeller to rotate at a high speed, forming a pressure difference at the upper and lower parts of the emulsifying impeller. The reaction fluid continuously sucks in from the holes on the back of the emulsifying impeller to the front of the impeller, forming a stable dispersion system on the back of the propelling impeller;

[0018] The propelling impeller is an axial-flow type impeller mainly dominated by propelling flow and supplemented by stirring and mixing;

[0019] The reactor tubes are evenly distributed. The propelling impeller of the agitator mainly generates an axial upward thrust in the flow field of the reaction fluid system during the stirring process;

[0020] The impeller shape and size of the propelling impeller are mainly of the axial-flow propelling type, and the blade form is preferably hyperbolic, swept-back hyperbolic wide blade surface type, and hyperbolic knife type, more preferably the swept-back hyperbolic wide blade surface type;

[0021] The heat exchange area includes a circulating water inlet, a circulating water outlet, heat exchange partition plates, and baffle plates. The heat exchange intervals are independently set to narrow the temperature range and make it close to the thermal reaction equilibrium point;

[0022] The reactor body is divided into several heat exchange areas. The heat exchange partition plates divide the reactor body into three heat exchange areas, and the circulating water inlet and the circulating water outlet are respectively arranged in each heat exchange area;

[0023] Several baffle plates are respectively arranged in each heat exchange area. Preferably, the baffle plates are of a spiral baffle plate structure;

[0024] The arrangement of the baffle plates in the three heat exchange areas is different. Preferably, the distance between the baffle plates in the energy explosion stage is 0.05 - 0.7 times the diameter of the reactor body, preferably 0.1 - 0.3 times;

[0025] The circulating water inlet and the circulating water outlet in the heat exchange area are respectively arranged in three different heat exchanger areas. When the reaction temperature fluctuates, the reaction temperature is adjusted by an independent cooling medium;

[0026] The separation area includes a lifting unit and a separation unit;

[0027] The lifting unit includes a spiral blade and a spiral blade guide cylinder. The spiral blade and the spiral blade guide cylinder adopt an interference fit method. While the agitator rotates, the reaction fluid is lifted to the separation unit through the lifting unit, and the rotation speed of the agitator is constant, and the lifting flow of the reaction fluid is stable;

[0028] The bottom of the spiral blade is adjacent to the top of the heat exchanger, and the top of the spiral blade is aligned with the separation interface of the separation zone. The spiral blade can be provided with a larger channel, which can improve the reaction material system with high solid content;

[0029] The separation unit is used to receive the reaction material lifted by the lifting unit and then separate it;

[0030] The separation unit includes a light-phase outlet, a light-phase reflux inlet, a light-phase reflux outlet, a heavy-phase reflux outlet, a heavy-phase reflux inlet and a heavy-phase outlet;

[0031] The separation unit is a static separation device, and the inside of the static separation device can be filled with structured packing; the structured packing is preferably an inclined baffle or a fiber polymer;

[0032] The light-phase outlet is used to transport the light-component logistics of the reaction material that has been separated by the separation unit. The light-phase reflux inlet can return the separated light-component logistics back to the reaction zone;

[0033] The light-phase reflux outlet is of an inserted structure, and the insertion position is at 2 / 3 of the height of the entire light-component logistics system. The light-phase reflux outlet is connected to the light-phase reflux inlet through a pipeline, and is used to adjust the ratio relationship between the light and heavy components of the entire reaction material system;

[0034] The heavy-phase outlet is used to transport the heavy-component logistics of the reaction material that has been separated by the separation unit. The heavy-phase reflux inlet can return the separated heavy-component logistics back to the reaction zone;

[0035] The heavy-phase reflux outlet is arranged at the bottom of the separation unit. The heavy-phase reflux outlet is connected to the heavy-phase reflux inlet through a pipeline, and is used to adjust the ratio relationship between the light and heavy components of the entire reaction material system.

[0036] Automatic control instruments and other facilities can be installed at both the two-phase inlet and outlet of the separation unit to more accurately control the ratio relationship between the light and heavy components of the entire reaction material system and optimize the entire reaction process.

[0037] The present invention also provides an application of the high-efficiency tubular reactor described in the present invention in exothermic reaction processes such as nitration reaction, alkylation reaction, chlorination reaction or diazotization.

[0038] The present invention also provides a nitration reaction, alkylation reaction, chlorination reaction and / or diazotization reaction process, including the following steps:

[0039] (1) Feed the reaction material system into the reaction material inlet arranged at the bottom of the reactor body of the high-efficiency tubular reactor described above in the present invention. Driven by the stirrer, the reaction material system circulates upward in the tubes of the high-efficiency tubular reactor described above in the present invention;

[0040] (2) As the reaction proceeds, a huge amount of heat is generated, causing the temperature of the reaction material system to rise. Through the several heat exchange zones provided in the above-mentioned high-efficiency tube reactor main body of the present invention, the reaction temperature can be accurately and quickly controlled;

[0041] (3) The reaction material system circulates upward in the tubes of the above-mentioned high-efficiency tube reactor of the present invention. When it reaches a certain liquid level, the reaction material flow is lifted to the separation unit through the lifting unit. Two-phase static separation is carried out according to the density difference and solubility of the reaction material system;

[0042] (4) During the separation process, the separated material flows are respectively returned to the light-phase reflux port inlet and the heavy-phase reflux port inlet through the light-phase reflux outlet and the heavy-phase reflux outlet to reach the reaction system of the reactor main body, and the ratio relationship of the light and heavy components in the entire reaction material system can be adjusted to optimize the production process conditions.

[0043] The beneficial effects of the present invention are as follows:

[0044] (1) Compared with the traditional reaction device, the reactor of the present invention organically couples the chemical reaction process, material lifting and transfer, and two-phase material separation.

[0045] (2) The present invention uses a combined impeller, which has both emulsifying and propelling functions at the same time. The stirring flow field is mainly axial thrust, and the entire reactor forms a high-speed flow field of a stirring vortex from bottom to top, and diffuses outward at a high speed from the center. It has a large volume flow rate, small backmixing, and no stirring dead angle. The kinetic energy is efficiently transferred, the stirring efficiency is high, and the power consumption is small;

[0046] (3) The tubular reactor of the present invention is better than the conventional reactor in terms of heat transfer and volume efficiency. It can control the reaction temperature more accurately and quickly, reach the target reaction temperature, reduce the occurrence of side reactions, and improve the product quality;

[0047] (4) The coupled high-efficiency tube reactor of the present invention can be flexibly applied to different reaction processes in different combined forms, greatly expanding the feasibility of various chemical reaction types in practical applications;

[0048] (5) The present invention can adjust the ratio relationship of the light and heavy components in the entire reaction material system through two different reflux ports;

[0049] (6) Through rapid emergency discharging, the two-phase material flows in the separation zone are quickly discharged to the reaction zone, eliminating the phenomenon of local high temperature in the static separation equipment and eliminating safety risks;

[0050] (7) According to the characteristics of energy release and reaction temperature rise, the reactor main body is divided into several heat exchange zones in the present invention, which can control the reaction temperature to reach the target reaction temperature more accurately and quickly, reduce the occurrence of side reactions, and improve the product quality;

[0051] (8) The reaction material system flows cyclically from bottom to top in the reactor tubes. When it reaches a certain liquid level, the reaction material flow is lifted to the separation unit by the lifting unit. Two-phase static separation is carried out according to the density difference and solubility of the reaction material system;

[0052] (9) During the separation process, the separated material flows are respectively returned to the light-phase reflux port inlet and the heavy-phase reflux port inlet to reach the reactor main body reaction system through the light-phase reflux outlet and the heavy-phase reflux outlet, which can adjust the ratio relationship of the light and heavy components in the whole reaction material system and optimize the production process conditions. Description of the Drawings

[0053] Figure 1 Conventional reaction temperature change trend diagram over time

[0054] Figure 2 Conventional chemical reaction energy release process stage partition diagram

[0055] Figure 3 Schematic diagram showing a high-efficiency tube reactor

[0056] Figure 4 Schematic diagram showing the structure of the stirrer 13. Figure 4 Among them, the emulsifying impeller 131, the propelling impeller 132

[0057] Figure 5 Multi-stage heat exchange zone and conventional heat exchange reaction fluid and cooling water temperature change comparison trend diagram

[0058] Figure 6 Schematic diagram showing the implementation process scheme of Example 1

[0059] Figure 7 Schematic diagram showing the comparison of the reactor temperature rise curve of Example 1 and the conventional reactor temperature rise curve

[0060] Figure 8 Schematic diagram showing the implementation process scheme of Example 2

[0061] Figure 9 Schematic diagram showing the implementation process scheme of Example 3

[0062] In the attached drawings of the present invention, there are reaction zone 1, reactor main body 11, reactor tubes 12, stirrer 13, transmission shaft 14, reaction material inlet 15, heat exchange zone 2, circulating water outlet 21, circulating water inlet 22, heat exchange partition baffle 23, baffle 24, separation zone 3, lifting unit 30, separation unit 31, spiral blade 301, spiral housing 302, light phase outlet 310, light phase reflux inlet 311, light phase reflux outlet 312, heavy phase reflux outlet 313, heavy phase reflux inlet 314, heavy phase outlet 315, light phase guide tube 316, material inlet 317, and material outlet 318. Detailed Embodiments

[0063] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention. Unless otherwise clearly stated, in the whole specification and claims, the term "comprise" or its variations such as "comprises" or "including" etc. shall be understood to include the stated components or steps, without excluding other components or steps.

[0064] In addition, for better illustration of the present invention, numerous specific details are given in the following detailed embodiments.

[0065] Those skilled in the art should understand that the present invention can be implemented without some specific details. In some embodiments, raw materials, methods, means, etc. well-known to those skilled in the art are not described in detail to highlight the gist of the present invention.

[0066] As Figure 3 shown, a high-efficiency tubular reactor includes an integrally integrated reaction zone 1, heat exchange zone 2, and separation zone 3, and the various zones influence, depend on, and are related to each other.

[0067] The reaction zone 1 includes a reactor main body 11; a stirrer 13 and a transmission shaft 14 are arranged inside the reactor main body 11, and the stirrer 13 is connected to a driving motor through the transmission shaft 14; a plurality of reactor tubes 12 are arranged inside the reactor main body 11.

[0068] The bottom of the reactor main body 11 is provided with a reaction material inlet 15, and reaction raw materials continuously and stably enter the reactor main body 11 from the reaction material inlet 15; at least one reaction material inlet 15 is provided, or it can be set to 2 or 3.

[0069] The agitator 13 is a key work component of the reactor. The work process mainly depends on two factors: convection and diffusion. Its function is to make the reaction fluid form a specific movement pattern inside the reactor body 11, flowing in a circulating manner from bottom to top within the reactor body 11; the impeller form of the agitator 13 determines the circulation frequency of the reaction fluid and the mixing effect of the reaction fluid.

[0070] The agitator 13 is in a combined form, as shown in Figure 4 the figure. It includes an emulsifying impeller 131 and a propelling impeller 132; the emulsifying impeller 131 is directly connected to the transmission shaft 14, and a porous structure is provided on the back of the emulsifying impeller 131.

[0071] The emulsifying impeller 131 is directly connected to the transmission shaft 14. The transmission shaft 14 drives the emulsifying impeller 131 to rotate at a high speed, forming a pressure difference between the upper and lower parts of the emulsifying impeller 131. The reaction fluid is continuously sucked from the holes on the back of the emulsifying impeller 131 to the front of the impeller. Relying on the strong shearing, impact, crushing, grinding and other effects generated by the emulsifying impeller 131, the reaction fluid is atomized and homogenized in a very short time. The dispersed liquid droplets are small and uniform, and can reach below the micron level, forming a stable dispersion system on the back of the propelling impeller 132.

[0072] The propelling impeller 132 is an axial-flow structure impeller dominated by propelling flow and supplemented by stirring and mixing. The rotation of its impeller generates a strong shearing force on the reaction fluid. Due to the resistance between liquids, the reaction fluid is transferred with great kinetic energy, strengthening the diffusion turbulence of the reaction fluid in the reactor body 11.

[0073] Driven by the motor, a certain swirling jet flow field is formed outside the impeller outlet. The mixing is carried out by using the shear stress along the jet surface, so that the liquid outside the fluid generates a stirring effect through friction. While achieving extreme mixing, a volume flow is formed.

[0074] The result of the action of the shearing force is to generate an axial thrust and a radial centrifugal force on the liquid. The axial thrust mainly pushes the liquid towards the direction of the transmission shaft 14, pushing the liquid forward to form a volume flow, so that the controlled fluid is stirred and pushed. The radial centrifugal force mainly makes the agitated liquid form a transverse stirring and mixing. The structural form and structural size of the impeller are important factors affecting the reaction mass transfer and momentum transfer performance.

[0075] The reactor tubes 12 are uniformly distributed. The reaction fluid is first homogenized by the emulsifying impeller 131, and then a stable volume flow is formed by the reaction fluid under the strong push of the propelling impeller 132.

[0076] The reaction fluid mainly passes through the reactor tubes 12 in a state close to plug flow. The axial flow of the fluid in the reactor tubes 12 is approximately ideal plug flow, and the chemical reaction rate in the plug flow is very fast, with a high single-pass conversion rate, so the reactor volume can be relatively small.

[0077] During the stirring process, the propelling impeller 132 of the stirrer 13 mainly generates an upward axial thrust in the flow field of the reaction fluid system, with a large volumetric flow rate, a gentle flow pattern, and no stirring dead zones, thus forming a stable volumetric flow field.

[0078] To achieve a uniform mixing state of the reaction fluid, the stirring impeller is first required to provide a sufficient circulation volume to avoid dead zones in the equipment, so that the reaction fluid can generate a rapid convective circulation motion.

[0079] The shape and size of the impeller of the propelling impeller 132 are mainly axial-flow propelling type, and the blade form is preferably hyperbolic, swept-back hyperbolic wide blade surface type, and hyperbolic knife type, and more preferably swept-back hyperbolic wide blade surface type.

[0080] The heat exchanger area 2 includes a circulating water inlet 21, a circulating water outlet 22, a heat exchange partition baffle 23, and a baffle 24.

[0081] In the present invention, the heat exchange intervals are independently set to narrow the temperature interval range and make it close to the heat reaction equilibrium point. Attached Figure 5 is a comparison trend chart of the temperature changes of the multi-stage heat exchange interval and the conventional heat exchange reaction fluid and cooling water. From the attached Figure 5 It can be seen that by adopting the multi-stage heat exchange interval, in the first heat exchange interval, the temperature drop amplitude is larger than that of the conventional heat exchange, and the temperature quickly approaches the target reaction temperature. In the second heat exchange interval, the temperature drop amplitude of the heat flow gradually becomes smaller and is relatively stable. The heat exchange in this area is the most intense. In the third heat exchange interval, the heat flow temperature is already very close to the reaction heat equilibrium point temperature, and the change approaches zero, and the heat exchange in this area is relatively gentle.

[0082] According to the energy release and reaction temperature rise characteristics, the reactor main body 11 of the present invention is divided into several heat exchange areas. The heat exchange partition baffle 23 divides the reactor main body 11 into three heat exchange areas, and the circulating water inlet 21 and the circulating water outlet 22 are respectively arranged in each heat exchange area;

[0083] To reduce the stagnation, backflow and dead zones of the shell-side cooling fluid, a plurality of baffle plates 24 are respectively arranged in each heat exchange area. The baffle plate 24 is of a spiral baffle structure, and the spiral baffle structure strengthens the turbulent effect of the cooling fluid between the tubes, generates turbulence on the surface of the heat transfer tubes, and improves the shell-side film heat transfer coefficient.

[0084] To ensure that the reaction temperature fluctuates within a low range and prevent the generation of by-products, the arrangement of the baffle plate 24 is different in the three heat exchange areas. AttachedFigure 2 As shown, during the energy release process of the chemical reaction, the temperature changes suddenly and sharply during the energy burst stage. To inhibit this situation, the baffle spacing in the heat exchange area needs to be set more closely to ensure the heat exchange effect of the cooling water. During the energy startup stage and the energy stable stage, since the reaction temperature changes relatively gently, the baffle spacing in the heat exchange area is sparser than before.

[0085] In the present invention, the spacing of the baffle 24 in the first heat exchange interval is 0.05 - 0.7 times the diameter of the reactor main body 11, preferably 0.1 - 0.3 times; to precisely control the temperature during the reaction, the circulating water inlet 21 and the circulating water outlet 22 in the heat exchange area 2 are respectively arranged in three different heat exchanger areas. When the reaction temperature fluctuates, the reaction temperature is adjusted by an independent cooling medium, quickly restored to stability, with strong anti-interference ability, and can reach the reaction set temperature control requirements in the shortest time.

[0086] The separation area 3 includes a lifting unit 30 and a separation unit 31.

[0087] The lifting unit 30 includes a spiral blade 301 and a spiral blade guide cylinder 302. The spiral blade 301 and the spiral blade guide cylinder 302 adopt an interference fit. While the stirrer 13 rotates, the reaction material flow is lifted to the separation unit 31 through the lifting unit 30. The rotation speed of the stirrer 13 is constant, and the lifting flow of the reaction material is stable. The bottom of the spiral blade 301 is adjacent to the top of the heat exchanger 2, and the top of the spiral blade 301 is aligned with the separation interface of the separation area 3. The reaction material flow uses the centrifugal force generated by the rotation of the spiral blade 301, and the guide cylinder 302 forces the reaction material to flow upward to achieve the lifting purpose. The spiral blade 301 can be provided with a larger channel, which can lift the reaction material system with a high solid content, further broadening the reaction and practical application scenarios.

[0088] The separation unit 31 is used to receive the reaction material lifted by the lifting unit 30 and then separate it.

[0089] The separation unit 31 includes a light phase outlet 310, a light phase reflux inlet 311, a light phase reflux outlet 312, a heavy phase reflux outlet 313, a heavy phase reflux inlet 314, and a heavy phase outlet 315.

[0090] The separation unit 31 is a static separation device, which performs static separation according to the density difference and solubility of the reaction material system, and is divided into a light component material flow and a heavy component material flow according to the size relationship of the density. Regular packing can be filled inside the static separation device; the regular packing is preferably an inclined baffle or a fiber polymer.

[0091] The light-phase outlet 310 is used to convey the light-component logistics separated from the reaction materials by the separation unit 31. The light-phase reflux inlet 311 can return the separated light-component logistics back to the reaction zone 1.

[0092] The light-phase reflux outlet 312 is of an inserted structure, and the insertion position is at 2 / 3 of the height of the entire light-component logistics system. The light-phase reflux outlet 312 is connected to the light-phase reflux inlet 311 through a pipeline, and is used to adjust the ratio relationship between the light and heavy components of the entire reaction material system.

[0093] The heavy-phase outlet 315 is used to convey the heavy-component logistics separated from the reaction materials by the separation unit 31. The heavy-phase reflux inlet 314 can return the separated heavy-component logistics back to the reaction zone 1.

[0094] The heavy-phase reflux outlet 313 is arranged at the bottom of the separation unit 31. The heavy-phase reflux outlet 313 is connected to the heavy-phase reflux inlet 314 through a pipeline, and is used to adjust the ratio relationship between the light and heavy components of the entire reaction material system.

[0095] Automatic control instruments and other facilities can be installed at both the two-phase inlet and outlet of the separation unit 31 to more precisely control the ratio relationship between the light and heavy components of the entire reaction material system and optimize the entire reaction process.

[0096] As is well known, chemical reactions are somewhat dangerous, especially for some violent chemical reaction types, their dangers are even more unpredictable. Therefore, in actual chemical production, a series of measures will be set up to eliminate potential safety hazards to the greatest extent. For example, for reaction equipment with a stirring drive motor, an emergency discharging measure will be added to prevent the reaction from continuing and reduce the huge energy generated during the reaction. However, for various separation equipment, especially, there will be a situation where the reaction material system does not react completely in the reactor and continues to react in the static separation equipment. Since this kind of reaction does not have the heat dispersion function of a stirring device, energy will accumulate locally, thus causing safety problems.

[0097] The separation unit 31 described in the present invention is provided with a light-phase reflux outlet 312 and a heavy-phase reflux outlet 313. In the case of local high temperature, rapid emergency discharging can be carried out through the two outlets to discharge the two-phase materials to the reaction zone 1, and the local high temperature phenomenon can be eliminated by stirring and cooling, thus eliminating safety risks.

[0098] The present invention also provides a process method for carrying out reactions using the above-mentioned tubular reactor, such as Figure 3 As shown, in one implementation method, the process includes reaction processes such as nitration reaction, alkylation reaction, chlorination reaction, and diazotization reaction, and specifically includes the following steps:

[0099] (1) Feed the reaction material system into the reaction material inlet 15 provided at the bottom of the reactor body 11 of the tubular reactor. Driven by the stirrer 13, the reaction material system circulates upward in the reactor tubes 12. The stirrer 13 atomizes and homogenizes the reaction material system, and after dispersion, the liquid droplets are small and uniform, thereby achieving efficient mass transfer and momentum transfer and improving the reaction efficiency;

[0100] (2) As the reaction proceeds, a large amount of heat is generated, causing the temperature of the reaction material system to rise. According to the energy release and reaction temperature rise characteristics of the present invention, the reactor body 11 is divided into several heat exchange zones, which can more accurately and quickly control the reaction temperature to reach the target reaction temperature, reduce the occurrence of side reactions, and improve the product quality;

[0101] (3) The reaction material system circulates upward in the reactor tubes 12. When it reaches a certain liquid level, the reaction material is lifted to the separation unit 31 by the lifting unit 30. Two-phase static separation is carried out according to the density difference and solubility of the reaction material system;

[0102] (4) During the separation process, the separated logistics are returned to the light-phase reflux inlet 311 and the heavy-phase reflux inlet 314 of the reactor body 11 through the light-phase reflux outlet 312 and the heavy-phase reflux outlet 313 respectively, which can adjust the ratio relationship of the light and heavy components in the entire reaction material system and optimize the production process conditions;

[0103] (5) In the case of local high temperature in the separation zone 3, rapid emergency discharging can be carried out through the light-phase reflux outlet 312 and the heavy-phase reflux outlet 313, and the two-phase logistics are discharged to the reaction zone 1 to eliminate safety risks.

[0104] The present invention will be further clarified below through the detailed description of the drawings and specific embodiments, but it is not a limitation of the present invention, and only serves as an example.

[0105] Example 1

[0106] As shown in Figure 6 Two heat exchange-reaction-phase coupling tubular reactors and one heat exchange-reaction-separation phase coupling high-efficiency tubular reactor are used in combination to realize the mononitration reaction of naphthalene.

[0107] Prepare a naphthalene-dichloroethane material system with a mass concentration of 25%. Feed the solution of this material system into the reaction material inlet 15 provided at the bottom of the first heat exchange-reaction-phase coupling tubular reactor body 11, and add 60% nitric acid at the other material inlet 15. Driven by the stirrer 13, the reaction material system circulates upward in the reactor tubes 12. 95% concentrated sulfuric acid returned from the third heat exchange-reaction-separation phase coupling high-efficiency tubular reactor is added to the first heat exchange-reaction-phase coupling tubular reactor through the material inlet 317. The stirrer 13 atomizes and homogenizes the reaction material system, forming a high-speed flow area near the impeller, so as to achieve efficient mass transfer and momentum transfer and carry out nitration chemical reactions;

[0108] As the nitration chemical reaction proceeds, a huge amount of heat will be generated, causing the temperature of the reaction material system to rise. According to the energy release and reaction temperature rise characteristics of the present invention, the reactor body 11 is divided into three heat exchange zones, and cooling water is added respectively from the circulating water inlet 22 to control the reaction temperature more accurately and quickly. Adjust the flow rate of the circulating water respectively to control the reaction temperature to 45°C;

[0109] The reaction material system circulates upward in the reactor tubes 12. When it reaches a certain liquid level, the reaction material overflows through the material outlet 318 and enters the material inlet 317 of the second heat exchange-reaction-phase coupling tubular reactor, and continues to react in the second tubular reactor;

[0110] When the second heat exchange-reaction-phase coupling tubular reactor reaches a certain liquid level, the reaction material overflows through the material outlet 318 of the second tubular reactor and enters the heavy phase reflux inlet 314 of the third heat exchange-reaction-separation phase coupling high-efficiency tubular reactor, and the final reaction is completed in the third tubular reactor;

[0111] The reaction material system circulates upward in the third reactor tubes to complete the final reaction. When it reaches a certain liquid level, the reaction material is lifted to the separation unit 31 by the lifting unit 30. According to the density difference and solubility of the reaction material system, the reaction material system is divided into a dichloroethane product light phase system and a concentrated sulfuric acid heavy phase system;

[0112] During the separation process, the materials separated through the light phase reflux outlet 312 and the heavy phase reflux outlet 313 are respectively returned to the light phase reflux port inlet 311 and the heavy phase reflux inlet 314 to reach the reaction system of the reactor body 11, which can adjust the ratio relationship of the light and heavy components of the entire reaction material system, optimize the production process conditions, and improve the ratio relationship of the chemical reaction products;

[0113] In the case of local high temperature occurring in the separation zone 3, emergency discharging can be quickly carried out through the light-phase reflux outlet 312 and the heavy-phase reflux outlet 313, discharging the two-phase logistics to the reaction zone 1 to eliminate safety risks.

[0114] The process synthesis product data of Example 1 are shown in Table 1.

[0115] Table 1 Process Synthesis Product Data Table of Example 1

[0116]

[0117] Comparative Example 1: The mononitration reaction of naphthalene was completed according to the process of CN118267963A.

[0118] The difference between Comparative Example 1 and Example 1 is that Comparative Example 1 uses a microchannel reactor process to realize the mononitration reaction process of naphthalene. The process synthesis product data using the microchannel reactor process are shown in Table 2.

[0119] Table 2 Process Synthesis Product Data Table of Comparative Example 1 with Microchannel Reactor Process

[0120]

[0121] From the comparison of the production data tables with Example 1, it can be seen that when using the microchannel reactor process, the selectivity of the product will decrease. The main reason is that the microchannel reaction conditions are relatively severe and cannot be effectively adjusted according to various reaction characteristics. It can be clearly concluded from Comparative Example 1 that when using the microchannel reaction process for the mononitration reaction of naphthalene, the nitration reaction rate cannot be controlled, resulting in an increase in the content of nitrophenol or dinitro products and a decrease in the purity of the effective product, and thus the selectivity of the product cannot be guaranteed.

[0122] Figure 7 Figure is the comparison chart of the reactor temperature rise curve of Example 1 and the conventional reactor temperature rise curve. Figure 7 The diagonal shaded part in the figure is the reaction material temperature control range of the reactor of the present invention, and the scattered point shaded part in the figure is the reaction material temperature control range of the conventional reactor. From Figure 7 it can be seen that the temperature range of the scattered point shaded part is far from the main reaction temperature, while the stable range of the diagonal shaded part represented by the present invention is closer to the target reaction temperature, which can ensure more optimized reaction conditions.

[0123] In Example 1, the process of the present invention can stably control the reaction temperature, improve the reaction conditions by adjusting the proportion of the concentrated sulfuric acid heavy-phase system, and reduce the impurity content of the product.

[0124] Taking an annual output of 1000 tons of mononitronaphthalene, the following table shows the parameters of the conventional stirring and the present invention in various aspects of the reactor. It can be seen that the present invention has better effects in terms of liquid storage capacity, power consumption, and stirring efficiency.

[0125] Table 3 Comprehensive comparison table of the process of the present invention and the conventional process in Example 1

[0126] Serial number Comparison item Conventional reaction The present invention Remarks 1 Liquid storage volume of the reactor m3 9 3 2 Total stirring power kw 16.5 9 3 Drainage volume of the stirrer m3 / s 1.76 2.42 4 Total heat exchange area m2 90 180

[0127] In Example 1, the process of the present invention can stably control the reaction temperature, improve the reaction conditions by adjusting the proportion of the concentrated sulfuric acid heavy phase system, and reduce the impurity content of the product.

[0128] Example 2

[0129] As shown in Figure 8 adopt a combination of three heat exchange - reaction - phase coupling tubular reactors to realize the alkylation reaction of synthesizing p - nitroanisole from p - nitrochlorobenzene.

[0130] Prepare a sodium methoxide - methanol material system with a mass concentration of 25%. Feed this material system solution into the reaction material inlet 15 provided at the bottom of the first heat exchange - reaction - phase coupling tubular reactor body 11. Add the main raw material p - nitrochlorobenzene into another material inlet 15, and add the solvent anhydrous methanol into another material inlet 15. Driven by the stirrer 13, the reaction material system circulates upward in the reactor tubes 12. A high - speed flow area is formed near the impeller of the stirrer 13, so as to achieve efficient mass transfer and momentum transfer and carry out the nitration chemical reaction.

[0131] As the alkylation reaction proceeds, a huge amount of heat will be generated, causing the temperature of the reaction material system to rise. According to the energy release and reaction temperature rise characteristics of the present invention, the reactor body 11 is divided into three heat exchange zones, and cooling water is added from the circulating water inlet 22 respectively to more accurately and quickly control the reaction temperature. Adjust the flow rate of the circulating water respectively to control the reaction temperature to 65 °C.

[0132] The reaction material system circulates upward in the reactor tubes 12. When it reaches a certain liquid level, the reaction material overflows through the material outlet 318 into the material inlet 317 of the second heat exchange - reaction - phase coupling tubular reactor and continues to react in the second tubular reactor.

[0133] When the second heat exchange - reaction - phase coupling tubular reactor reaches a certain liquid level, the reaction material overflows through the material outlet 318 of the second tubular reactor into the material inlet 317 of the third heat exchange - reaction - phase coupling tubular reactor and completes the final reaction in the third tubular reactor.

[0134] The alkylation reaction for synthesizing p-nitroanisole from p-nitrochlorobenzene is achieved by combining three series-connected heat exchange-reaction-phase coupling tubular reactors. The process equipment and operation are simple, and the product quality meets the requirements. Due to the use of an efficient stirring impeller, the energy consumption during production operation is economical. For example, in a p-nitroanisole production plant with an annual output of 15,000 tons, the reaction synthesis process uses the above-mentioned series-connected heat exchange-reaction-phase coupling tubular reactors. The power of a single device is 4 KWh, and three series-connected devices are used, with a total device power of 12 KWh.

[0135] Compared with the conventional synthesis of p-nitroanisole products using continuous kettle equipment, three series-connected kettle equipment are also required. The power of a single device is at least 11 KWh, and the total device power is 33 KWh.

[0136] From the comparison of the data of conventional production equipment, it can be seen that when using three series-connected heat exchange-reaction-phase coupling tubular reactors to combine the reaction and synthesize p-nitroanisole products, the annual power consumption is at least saved by 1814 MW. In today's market environment with increasingly fierce competition, the process device of the present invention has more market advantages.

[0137] Example 3

[0138] As shown in Figure 9 , the dinitration reaction of benzene is achieved by combining five series-connected heat exchange-reaction-separation phase coupling high-efficiency tubular reactors. The first two tubular reactors complete the mononitration reaction process of benzene with benzene as the raw material, and the last three tubular reactors complete the dinitration reaction process of benzene with the mononitration product of benzene - nitrobenzene as the raw material.

[0139] The raw material benzene is fed into the reaction material inlet 15 provided at the bottom of the first heat exchange-reaction-separation phase coupling high-efficiency tubular reactor body 11, and another raw material, 98% nitric acid, is added at another material inlet 15. The concentrated sulfuric acid returned from the second heat exchange-reaction-separation phase coupling high-efficiency tubular reactor is added to the light-phase reflux inlet 311 of the first tubular reactor through the heavy-phase outlet 315. Driven by the stirrer 13, the reaction material system circulates upward in the reactor tubes 12. A high-speed flow area is formed near the impeller of the stirrer 13, so as to achieve efficient mass transfer and momentum transfer and carry out nitration chemical reactions.

[0140] As the nitration reaction proceeds, a large amount of heat will be generated, causing the temperature of the reaction material system to rise. According to the energy release and reaction temperature rise characteristics of the present invention, the reactor body 11 is divided into three heat exchange zones, and cooling water is added from the circulating water inlet 22 respectively to more accurately and quickly control the reaction temperature.

[0141] The reaction material system circulates upward in the tubes of the tubular reactor to carry out the mononitration reaction. When it reaches a certain liquid level, the reaction material flow is lifted to the separation unit 31 by the lifting unit 30. According to the density difference and solubility of the reaction material system, the reaction material system is divided into a light phase system of mononitrobenzene product and a heavy phase system of concentrated sulfuric acid.

[0142] As the raw materials continue to be added, the liquid level in the separation unit 31 continuously rises. The light phase system of mononitrobenzene product overflows through the light phase outlet 310 and enters the heavy phase reflux inlet 314 of the second tubular reactor. The heavy phase system of concentrated sulfuric acid in the reaction synthesis is discharged from the heavy phase outlet 315.

[0143] 98% nitric acid as raw material is supplemented and added at the logistics inlet 15 of the second tubular reactor, and continues to react in the second tubular reactor with the light phase system overflowing from the light phase outlet 310 of the first tubular reactor and the concentrated sulfuric acid returned from the heavy phase outlet 315 of the third tubular reactor until all the raw materials react to form mononitrobenzene.

[0144] And so on, 98% nitric acid as raw material is continuously supplemented and added at the logistics inlets 15 of the third, fourth, and fifth tubular reactors, and continues to react in the third, fourth, and fifth tubular reactors with the light phase system overflowing from the corresponding light phase outlet 310 of the previous tubular reactor and the concentrated sulfuric acid returned from the heavy phase outlet 315 of the next tubular reactor until all the mononitrobenzene reacts and is converted into dinitrobenzene. The difference is that 95% concentrated sulfuric acid is added at the logistics inlet 15 of the fifth tubular reactor.

[0145] During the separation process, the logistics separated through the light phase reflux outlet 312 and the heavy phase reflux outlet 313 are respectively returned to the light phase reflux inlet 311 and the heavy phase reflux inlet 314 to reach the reaction system of the reactor main body 11, which can adjust the ratio relationship of the light and heavy components in the whole reaction material system, optimize the production process conditions, and improve the ratio relationship of the chemical reaction products;

[0146] In the case of local high temperature occurring in the separation area 3 of the five tubular reactors, emergency discharging can be carried out quickly through the light phase reflux outlet 312 and the heavy phase reflux outlet 313, and the two-phase logistics are discharged to the reaction area 1 to eliminate safety risks, which greatly ensures the inherent safety of the whole reaction system.

[0147] Using the process of the present invention and comparing it with the continuous stirred tank reaction process and the microchannel process, the advantages and disadvantages of the present invention in terms of process scheme, equipment investment cost, equipment pipeline installation cost, material system volume, process characteristics, and safety are comprehensively described. Table 4 below is a comparison table of each process for the production device of 100,000 tons of dinitrobenzene products per year in Example 3.

[0148] Table 4 Comparison Table of Process Production Devices in Example 3

[0149]

[0150]

[0151] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the technical concept scope of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A high-efficiency tubular reactor, comprising a reaction zone, a heat exchange zone and a separation zone which are integrally coupled, characterized in that: The reaction zone includes a reactor body; a stirrer and a transmission shaft are arranged inside the reactor body, and the stirrer is connected to a driving motor through the transmission shaft; A plurality of reactor tubes are arranged inside the reactor body; The reactor tubes are evenly distributed; A reaction stream inlet is provided at the bottom of the reactor body, and the reaction raw materials continuously enter the reactor body from the reaction stream inlet; The reactor body is divided into a number of heat exchange zones; The heat exchange area includes a circulating water inlet and a circulating water outlet; Each heat exchange zone is respectively provided with a plurality of baffles; The separation zone includes a lifting unit and a separation unit.

2. The high-efficiency tubular reactor according to claim 1, characterized in that: The reactant flow inlet is at least one, or may be two or three; the heat exchange partitioning plate divides the reactor body into three heat exchange zones, and the circulating water inlet and circulating water outlet are respectively arranged in each heat exchange zone.

3. The high-efficiency tubular reactor according to claim 1 or 2, characterized in that: The lifting unit comprises a spiral blade and a spiral blade guide tube; the spiral blade and the spiral blade guide tube adopt a clearance fit mode; The bottom of the spiral blade is adjacent to the top of the heat exchanger, and the top of the spiral blade is aligned with the separation interface of the separation zone.

4. The high-efficiency tubular reactor according to any one of claims 1 to 3, characterized in that: The separation unit is used to receive the reaction materials lifted by the lifting unit and then separate them; the separation unit includes a light phase outlet, a light phase reflux inlet, a light phase reflux outlet, a heavy phase reflux outlet, a heavy phase reflux inlet and a heavy phase outlet; preferably, the light phase reflux outlet is an inserted structure, and the insertion position is 2 / 3 of the height of the entire light component flow system; the heavy phase reflux outlet is arranged at the bottom of the separation unit; the heavy phase reflux outlet is connected to the heavy phase reflux inlet through a pipeline.

5. The high-efficiency tubular reactor according to any one of claims 1 to 4, characterized in that: The agitator is a combination form, including an emulsifying impeller and a propulsion impeller; the emulsifying impeller is directly connected to the transmission shaft, and a porous structure is arranged on the back of the emulsifying impeller.

6. The high-efficiency tubular reactor according to any one of claims 1 to 5, characterized in that: The propulsion impeller is an axial flow impeller with propulsion flow as the main function and stirring and mixing as the secondary function; the impeller shape and size of the propulsion impeller are mainly axial flow propulsion type, and the blade form is preferably hyperbolic, swept hyperbolic wide blade shape and hyperbolic knife shape, and the swept hyperbolic wide blade shape is more preferred.

7. The high-efficiency tubular reactor according to any one of claims 1 to 6, characterized in that: The baffles are spiral baffle structures; the spacing between the baffles is arranged differently in the three heat exchange zones; the baffles are in the first heat exchange zone, and the spacing is 0.05-0.7 times, preferably 0.1-0.3 times, of the diameter of the reactor body.

8. The high-efficiency tubular reactor according to any one of claims 1 to 7, characterized in that: The separation unit is a static separation device, and the interior of the static separation device can be filled with structured fillers; the structured fillers are preferably inclined partitions or fiber polymers; the light phase outlet is used to transport the light component flow of the reaction material that has been separated by the separation unit; preferably, the two-phase inlet and outlet of the separation unit are equipped with automatic control instruments.

9. A reaction process in which the high-efficiency tubular reactor according to any one of claims 1 to 8 produces heat.

10. The exothermic reaction process according to claim 9, characterized in that: The exothermic reaction process is selected from nitration, alkylation, chlorination or diazotization.

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