Multi-zone combined reactor

Abstract

The present application relates to petrochemical equipment technical field, specifically relates to multi-section combined reactor, including series pipe reaction zone and stirring reaction zone, series pipe reaction zone includes straight sleeve pipe, bent sleeve pipe and jacket communication pipe, stirring reaction zone includes kettle cylinder, kettle jacket flow channel arranged outside kettle cylinder and stirrer penetrated into kettle cylinder, the present application integrates stirring reaction zone into series pipe reaction zone, reduces floor space, can share a set of mounting structure to fix, reduces installation cost, is favorable to improve the overall structural strength and rigidity of reactor, the stirring reaction zone makes up for the deficiency that series pipe reaction zone cannot be stirred evenly, can play the advantage of liquid and auxiliary material stirring, converts liquid into slurry, series pipe reaction zone makes up for the deficiency that cannot be reacted thoroughly in small space of stirring reactor, can play the advantage of long flow sufficient reaction, converts slurry into powdery solid product, and through adjustment, the whole reactor can be made as different types of reactor, and the application range is wide.

Description

Technical Field

[0001] This invention relates to the field of petrochemical equipment technology, specifically to a multi-section combined reactor. Background Technology

[0002] Polypropylene and polyethylene are the most widely produced and consumed general-purpose synthetic resins, and their production and usage are gradually increasing. There are three main production technologies for them: slurry polymerization, gas-phase polymerization, and solution polymerization. The slurry polymerization process is the primary method, and it can be further divided into stirred tank reactors and tubular reaction zones based on the reactor type. With economic development, the applications of polypropylene products are becoming increasingly widespread, which places higher demands on the mechanical and processing properties of polypropylene.

[0003] A stirred reactor is a type of reaction vessel, consisting of a stirrer and a vessel body. The stirrer includes a transmission device, a stirring shaft, and an impeller. The vessel body includes a cylinder, a jacket and internal components, a coil, and a guide tube. An existing stirred reactor, such as the polypropylene preparation reaction vessel disclosed in Chinese patent document CN218222455U, includes a reaction vessel body, a mixing and cleaning mechanism, and a rinsing and cleaning mechanism. A sealed vessel cover is connected to one side of the reaction vessel body. The mixing and cleaning mechanism is located inside the reaction vessel body and includes a stirring shaft. Multiple sets of evenly distributed stirring blades are provided on the outer side of the stirring shaft. Each set of stirring blades is connected to a fixing ring. The rinsing and cleaning mechanism is located inside the reaction vessel body and includes a liquid conveying ring. A connecting guide ring is connected to the side of the liquid conveying ring closest to the stirring shaft, and the connecting guide ring is rotatably connected to the stirring shaft.

[0004] For example, Chinese patent document CN213434402U discloses a modified polypropylene foamed bead reactor, which relates to the field of reactor technology. It addresses the problems of existing modified polypropylene foamed bead reactors, which, while ensuring sealing performance, cannot effectively perform internal maintenance and cleaning, and have insufficient stability in stirring and rotation. The reactor shell is externally fitted with an outer jacket, and an upper sealing cover is installed on top of the reactor shell. Sealing connection edging is installed on the outer side of the connection between the reactor shell and the upper sealing cover. A connecting transmission frame is installed at the middle position above the upper sealing cover. Mounting support frames are installed on both sides of the outer jacket and the upper sealing cover. An electric telescopic rod is installed between the two mounting support frames. A rotating stirring rod is installed at the middle position inside the reactor shell.

[0005] Traditional polypropylene production processes employ a series of reactors to produce bimodal polypropylene, meaning products with different molecular weights are produced in different reactors. For example, Chinese patent document CN104231129A discloses a method for preparing polypropylene that uses at least two parallel liquid-phase stirred reactors connected in the presence of a catalyst, followed by a series connection with a gas-phase fluidized bed reactor, to polymerize propylene. The catalyst in the liquid-phase stirred reactor includes a main catalyst, a co-catalyst, and an external electron donor. This method is based on the fundamental principle of liquid-phase + gas-phase propylene polymerization, employing a process where parallel liquid-phase stirred reactors are connected to a gas-phase reactor. By adding main catalysts with different polymerization properties, electron donors with different hydrogen sensitivity, and using differentiated hydrogen regulation control in the liquid-phase reactor, it aims to develop polypropylene products with wide molecular weight distributions and other high-performance polypropylene products.

[0006] For example, Chinese patent document CN117085606A discloses a production apparatus and method for high-impact copolymer polypropylene products, comprising, in sequence, a prepolymer reactor, a loop liquid-phase reactor, an intermediate flash separation system, a dehydrogenation and conveying system, a horizontal gas-phase reactor, a powder post-processing system, and an additive and granulation system. This production apparatus and process, along with a new additive formulation, solves the problem of poor quality in existing loop-phase processes for producing impact-resistant copolymer polypropylene products. It also overcomes the limitation of existing liquid-phase loop reactor + horizontal stirred gas-phase reactor processes in producing impact-resistant copolymer products, enabling the production of high-quality high-impact copolymer polypropylene products.

[0007] The applicant currently manufactures numerous serial reaction zones, which, depending on production capacity, mainly consist of several straight sleeves, outer elbows, inner elbows, mounting supports, and connecting beams. Each cycle consists of two straight sleeves and two elbows. Because the polymerization reaction generates heat, cooling water within the jacket dissipates the heat. The outer sleeve of the straight sleeve is equipped with a corrugated expansion joint, mounting supports, and support beams. The inner elbows are connected to both ends of the inner sleeves via flanges, forming a continuous flow path. An outer elbow is fitted around the inner elbow, creating an annular curved jacket flow channel between them. A connecting pipe on the side connects the jackets of the straight sleeves and the curved jacket flow channel into a single flow path. The connecting beams are bolted to the support beams, assembling the straight sleeves into a three-dimensional frame. The tandem pipe reaction zone is supported by multiple foundations, meaning each straight bushing has its own mounting support. Errors in the length, axial position, orientation, elevation, and spacing of the straight bushings, as well as manufacturing errors in the parallelism of the straight bushings, the verticality of the flanges, and the bends, all simultaneously affect the sealing performance of the tandem pipe installation. The installation of the tandem pipe reaction zone can be divided into two types: vertical and inclined. The latter occupies a slightly larger area, but its overall structure is more stable than the former.

[0008] For example, such as Figure 1As shown, a vertically installed serial tube reaction zone mainly consists of six straight sleeves (R1, R2, ... R6), five 180° large bends (A1, A2, A3, and two bends at the bottom), and one 90° bend connected sequentially to form a circulating system. It sits on a high platform foundation and is connected to the outer pipes via five outer bends located at the inner bends. An axial flow pump is installed at the inner bend at the bottom of the serial tubes. The reactants enter the serial tube reaction zone through the reactant inlet 1A, and are stirred and circulated within the tubes under the drive of the axial flow pump. Under the action of the catalyst, they react to form a slurry of polypropylene, which is discharged through the reactant outlet 1B into the granulation system. The cooling medium enters through the cooling medium inlet of the jacketed flow channel and exits through the cooling medium outlet of the jacketed flow channel. Six mounting supports are located at the bottom of each straight sleeve R1, R2, R3, R4, R5, and R6. The jackets are interconnected by five jacket connecting pipes. Cooling water within the jackets carries away the heat released from the reaction in the inner tubes through the partition walls, maintaining the normal operation of the reaction process. To compensate for the difference in thermal expansion displacement between the inner and outer tubes due to temperature differences, expansion joints are attached to the jackets. The jackets also include expansion joints, support beams, and supports. Adjacent jackets are connected by structural steel sections, forming several spatial platforms. The inner tube of the straight sleeve is connected to the inner elbow of the bent sleeve via a main flange. The jacket flow channels of the straight sleeve and the jacket flow channels of the bent sleeve are connected via jacket connecting pipes, each with side flanges at both ends.

[0009] The above describes the existing stirred reaction zone and tubular reaction zone reactors. Each type has its own characteristics. The tubular reaction zone has a long flow channel, providing sufficient reaction time for the slurry medium, allowing the reaction to gradually become complete. The stirred reaction zone has a large volume within a small space, providing sufficient time for the addition and mixing of additives for liquid and suspended media, ensuring uniform reaction during the reaction process.

[0010] While the above describes existing technologies involving multiple stirred reaction zones connected in series, or stirred reactors connected in series with other types of reactors, the inconsistent residence time distribution in these reactors leads to defects in the uniformity of the produced products. Furthermore, such series-tube reaction zones are extremely large, equivalent to a building exceeding ten stories. Conventional techniques typically use both series-tube and stirred reaction zones independently, resulting in the short flow channels and incomplete reactions in stirred reaction zones, and uneven mixing in series-tube reaction zones. The technical inspiration from existing technologies involving connecting different reactors in series involves connecting independent reactors via tubes / cylinders, with reactants completing the reaction in one independent reactor before flowing to the next. However, this approach requires improvement in the following aspects:

[0011] 1. Each reactor is arranged independently, which occupies a large space. Each reactor must have an independent installation structure to fix it, resulting in high installation costs.

[0012] 2. When the reactors are connected in series, the reactants must pass through each reactor in sequence to complete the process flow, which limits the applicable process. Summary of the Invention

[0013] In view of the above-mentioned technical problems in the existing technology, the present invention provides a multi-section combined reactor.

[0014] It should be noted that the prior art exists in the practice of connecting stirred reaction zones in series in a "loop" reactor, but the "loop" refers to the pipeline forming a circulation loop, which is also the case of independent reactors connected in series mentioned in the background art. It is not a structure in which inner and outer tubes intersect to form a jacket heat exchange structure. Therefore, it cannot realize the function of integrating a stirred reaction zone inside the series reaction zone of the present invention. The two are essentially different.

[0015] To achieve the above objectives, the present invention provides the following technical solution:

[0016] A multi-section combined reactor is provided, including a series-tube reaction zone and a stirred reaction zone. The series-tube reaction zone includes straight tubes, bent tubes, and a jacketed connecting pipe. The straight tubes include vertically arranged inner and outer tubes, with the inner tube passing through the outer tube to form an annular straight jacketed flow channel. Each bent tube includes an outer bend and an inner bend, with the outer bend fitting over the inner bend to form an annular bent jacketed flow channel. The inner tubes of different straight tubes are connected in series via inner bends to form a central flow channel for transporting reactants and for the reaction. Both ends of the straight and bent jacketed flow channels are provided with sealing structures to seal the two ports of the straight and bent jacketed flow channels. The straight and bent jacketed flow channels are connected in series via the jacketed connecting pipe to form an outer annular flow channel for transporting cooling medium.

[0017] The stirred reaction zone includes a vessel body, a vessel jacket flow channel located outside the vessel body, and a stirrer inserted into the vessel body. A connection zone is formed by partially reducing the length of the straight and / or bent sections of the pipe in the serial reaction zone. The vessel body is located at the connection zone. The inlet and outlet of the vessel body are connected via a main valve to the interface formed by the reduction of sections in the central flow channel, thus making the vessel body a partial section of the central flow channel. The inlet and outlet of the vessel jacket flow channel are connected via a secondary valve to the interface formed by the reduction of sections in the outer ring flow channel, thus making the vessel jacket flow channel a partial section of the outer ring flow channel.

[0018] As a further alternative, the two ends of the bent sleeve are each provided with a first flange for connecting the ends of the straight sleeve.

[0019] As a further alternative, the interface formed by removing the straight sleeve and / or bent sleeve is provided with a second flange for connecting the vessel body.

[0020] As a further alternative, each pair of straight sleeves in the serial reaction zone and the connected bent sleeve form a circulation unit, and the straight sleeve is divided into an ascending section and a descending section according to the flow direction of the medium inside. The ascending section located on the outermost side is connected to a feed pipe, and the descending section located on the outermost side is connected to a discharge pipe.

[0021] As a further optional solution, the number of the circulation units is one, with the feed pipe connected to the lower end of the rising section and the discharge pipe connected to the lower end of the falling section, and the stirring reaction zone arranged in the falling section, the rising section and / or the bend sleeve.

[0022] As a further alternative, the number of the circulation units is two or more, and they are connected in series with each other, with the stirred reaction zone arranged in the descending section, the ascending section and / or the bend sleeve.

[0023] As a further alternative, the stirred reaction zone is arranged in the lower bent sleeve, and the circulation units before and after the stirred reaction zone are arranged symmetrically.

[0024] As a further optional solution, the number of the serial tube reaction zones is two or more, the vessel body of the same stirred reaction zone is simultaneously connected to the central flow channels of two or more serial tube reaction zones, and the vessel jacket flow channel of the same stirred reaction zone is simultaneously connected to the outer ring flow channels of two or more serial tube reaction zones.

[0025] As a further optional feature, the stirred reaction zone is also equipped with a normally closed spare material port connected to the vessel body and a spare cooling port connected to the vessel jacket flow channel.

[0026] As a further alternative, the agitator is arranged coaxially with the vessel body, which can be arranged horizontally or vertically.

[0027] The beneficial effects of this invention are:

[0028] The multi-section combined reactor of the present invention has the following advantages compared with the prior art:

[0029] 1. Integrating the stirred reaction zone into the serial tube reaction zone reduces the footprint, allows for the use of a single mounting structure for fixation, lowers installation costs, and helps improve the overall structural strength and rigidity of the reactor.

[0030] 2. When the outer ring flow channel formed by the straight jacket flow channel and the curved jacket flow channel connected in series is closed, and the central flow channel formed by the inner tube and the outer bend connected in series is equivalent to a pure pipe, the entire reactor becomes a stirred reaction zone.

[0031] When no catalyst or additive is added to the vessel body of the stirred reaction zone, the vessel body is only equivalent to a pure intermediate homogenizer. At the same time, an axial flow pump connected to the inlet of the jacketed straight pipe pushes the material forward, and the entire reactor becomes a special serial tube reaction zone.

[0032] When the stirred reaction zone is removed and a jacketed pipe of equal height to the connection zone is installed at the original connection zone position, the entire reactor becomes a regular serial tube reaction zone.

[0033] Therefore, this multi-section combined reactor is suitable for different process requirements.

[0034] 3. The stirred reaction zone compensates for the inability of the serial tube reaction zone to achieve uniform mixing, and can take advantage of the mixing of liquids and auxiliary materials to transform liquids into slurries; the serial tube reaction zone compensates for the inability of the stirred reactor to achieve complete reaction in a small space, and can take advantage of the long flow and full reaction to transform slurries into powdered solid products. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the existing serial tube reaction zone structure.

[0036] Figure 2 This is a schematic diagram of the structure of the first embodiment of the multi-section combined reactor of the present invention.

[0037] Figure 3 This is a schematic diagram of the structure of a second embodiment of the multi-section combined reactor of the present invention.

[0038] Figure 4 This is a schematic diagram of the third embodiment of the multi-section combined reactor of the present invention.

[0039] Figure 5 This is a schematic diagram of the fourth embodiment of the multi-section combined reactor of the present invention.

[0040] Figure 6 This is a schematic diagram of the fifth embodiment of the multi-section combined reactor of the present invention.

[0041] Figure 7 This is a schematic diagram of the sixth embodiment of the multi-section combined reactor of the present invention.

[0042] Figure label:

[0043] Serial tube reaction zone 1, straight sleeve 11, inner tube 111, outer tube 112, bent sleeve 12, outer elbow 121, inner elbow 122;

[0044] 2. Stirred reaction zone; 21. Reactor body; 22. Reactor jacket flow channel; 23. Stirrer;

[0045] 3. First flange; 4. Second flange; 5. Third flange; 6. Feed pipe; 7. Discharge pipe. Detailed Implementation

[0046] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0047] The multi-section combined reactor in this embodiment, such as Figure 2 As shown, it includes a series-tube reaction zone 1 and a stirred reaction zone 2. The series-tube reaction zone 1 can be combined with... Figure 1 To understand this, the system includes a straight sleeve 11, a bent sleeve 12, and a jacketed connecting pipe (the jacketed connecting pipe is not shown in the figure; its structure can be found in Chinese patent documents CN202321418122.3 and CN202321418119.1). The straight sleeve 11 includes a vertically arranged inner pipe 111 and an outer pipe 112. The inner pipe 111 passes through the outer pipe 112, thus forming an annular straight jacketed flow channel between the outer wall of the inner pipe 111 and the inner wall of the outer pipe 112. Each bent sleeve 12 includes an outer bend 121 and an inner bend 122. The outer bend 121 is fitted over the inner bend 122, thus forming an annular bent jacketed flow channel between the outer wall of the inner bend 122 and the inner wall of the outer bend 121. The inner pipes 111 of different straight sleeves 11 are connected in series via inner bends 122 to form a central flow channel for transporting reactants and for the reaction. Both ends of the straight jacketed flow channel and the curved jacketed flow channel are respectively provided with sealing structures, thereby sealing the two ports of the straight jacketed flow channel and the two ports of the curved jacketed flow channel; the straight jacketed flow channel and the curved jacketed flow channel are connected in series through the jacketed connecting pipe to form an outer ring flow channel for conveying the cooling medium.

[0048] The stirred reaction zone 2 includes a vessel body 21, a vessel jacket flow channel 22 disposed outside the vessel body 21, and a stirrer 23 inserted into the vessel body 21. A connection area is formed by partially reducing a section of the straight sleeve 11 of the serial tube reaction zone 1. The vessel body 21 is located at the connection area. The inlet and outlet of the vessel body 21 are connected via a main valve to the interface formed by the reduction of the central flow channel section, thus making the vessel body 21 a partial section of the central flow channel. The inlet and outlet of the vessel jacket flow channel 22 are connected via a secondary valve to the interface formed by the reduction of the outer ring flow channel section, thus making the vessel jacket flow channel 22 a partial section of the outer ring flow channel.

[0049] The compatibility between the serial tube reaction zone 1 and the stirred reaction zone 2 is such that the media are interconnected, and the flow rates are coordinated by inlet and outlet valves. One key connection between the two is that although their processes and media differ when operating independently according to traditional methods, and the stirred reaction process media is gaseous, the final product is polyolefin (polypropylene PP or polyethylene PE), albeit with different grades and qualities. Regardless of whether the raw material is gas or liquid, the process of transforming it into polyolefin powder and ultimately granules requires a viscous slurry / material, and the serial tube reaction zone 1 is this slurry reaction process. Therefore, there is a mutual need for various reaction zone structures to combine their advantages in order to expand production capacity, broaden product range, and improve quality. The stirred reaction zone 2 compensates for the inability of the serial tube reaction zone 1 to achieve uniform mixing, leveraging the advantages of mixing liquids and auxiliary materials to transform liquids into slurries; the serial tube reaction zone 1 compensates for the incomplete reaction in the small space and large volume of the stirred reaction zone 2, leveraging the advantage of continuous flow and thorough reaction to transform slurries into powdered solid products.

[0050] In this embodiment, the two ends of the bent jacket are respectively provided with a first flange 3 for connecting to the end of the straight jacket. The interface formed by the reduction of the straight sleeve 11 is provided with a second flange 4 for connecting to the vessel body 21. The reaction zones of the two structures are connected by flanges and are detachable. The production capacity of the serial tube reaction zone 1 and the stirred reaction zone 2 may be equal or different.

[0051] The stirred reaction zone 2 is also equipped with a normally closed spare material inlet connected to the vessel shell 21 and a spare cooling inlet connected to the vessel jacket flow channel 22. It retains the original functions of the two reactors and can operate the original two processes of the two reactors respectively. Depending on the production process requirements, the connection to the straight sleeve 11 or to an independent material inlet / outlet can be adjusted via valves.

[0052] In this embodiment, each pair of straight sleeves 11 in the serial tube reaction zone 1 and the connected bent sleeve form a circulation unit. The straight sleeves 11 are divided into rising sections and falling sections according to the flow direction of the medium inside. The rising section located on the outermost side is connected to the feed pipe 6, and the falling section located on the outermost side is connected to the discharge pipe 7. The reactants flow in from the inlet M, rise in the direction H, fall in the direction L, and finally flow out from the outlet N. Figure 2The number of circulation units described herein is one, namely one straight sleeve 11 as the rising section, one straight sleeve 11 as the falling section, and one bent sleeve 12. Together with the stirred reaction zone 2, they form a closed-loop single-loop reactor, with only one upper and lower circulation loop. Its advantages are: simple and easy-to-implement structure and convenient maintenance. The feed pipe 6 is connected to the lower end of the rising section, and the discharge pipe 7 is connected to the lower end of the falling section. The stirred reaction zone 2 is located in the falling section. However, depending on the actual process requirements, it can be arranged in the rising section or the bent sleeve 12, or the stirred reaction zone 2 can be arranged in different locations.

[0053] In this embodiment, the ends of the feed pipe 6 and the discharge pipe 7 are provided with third flanges 5 for easy detachable connection. It can be seen that... Figure 1 The feed pipe 6 extends downwards, while the discharge pipe 7 extends upwards, which facilitates the adjustment of the overall structure's center of gravity and improves stability.

[0054] Compared with existing technologies, it has the following advantages:

[0055] 1. Integrating the stirred reaction zone 2 into the serial tube reaction zone 1 reduces the footprint, allows for the use of a single mounting structure for fixation, lowers installation costs, and helps improve the overall structural strength and rigidity of the reactor.

[0056] 2. When the outer ring flow channel formed by the straight jacket flow channel and the curved jacket flow channel connected in series is closed, and the central flow channel formed by the inner tube 111 and the outer elbow 121 connected in series is equivalent to a pure pipe, the entire reactor becomes a stirred reaction zone 2.

[0057] When no catalyst or additive is added to the vessel body 21 of the stirred reaction zone 2, the vessel body 21 is only equivalent to a pure intermediate homogenizer. At the same time, the axial flow pump connected to the inlet of the jacket straight pipe pushes the material forward, and the entire reactor becomes a special serial tube reaction zone 1.

[0058] When the stirred reaction zone 2 is removed and a jacketed pipe of equal height to the connection zone is installed at the original connection zone position, the entire reactor becomes a regular serial tube reaction zone 1.

[0059] Therefore, this multi-section combined reactor is suitable for different process requirements.

[0060] 3. The stirred reaction zone 2 compensates for the inability of the serial tube reaction zone 1 to achieve uniform mixing, leveraging the advantages of mixing liquids and auxiliary materials to transform liquids into slurries. The serial tube reaction zone 1 compensates for the incomplete reaction within the small space of the stirred reactor, leveraging the advantages of a long flow for thorough reaction, transforming the slurry into powdered solid products. More importantly, compared to the simple series connection of ordinary independent reactors, in this embodiment, the stirred reaction zone 2 is integrated into the serial tube heat exchanger. Reactants can undergo sufficient reaction time in the long flow channel of the serial tube reaction zone 1, allowing the reaction to gradually become complete. Then, after being thoroughly stirred in the stirred reaction zone 2, the liquid and suspended medium are provided with sufficient auxiliary materials and mixing time before continuing to flow into the serial tube reaction zone 1.

[0061] In addition, the agitator 23 inside the vessel body 21 can adopt a planar mesh structure, with the plane arranged longitudinally along the drive shaft. The two ends of the agitator 23 in the longitudinal direction are knife-edge shaped wedges to reduce resistance to the axial flow of materials.

[0062] In this embodiment, the stirrer 23 and the vessel body 21 are arranged coaxially. In fact, the vessel body 21 is arranged horizontally or vertically. The following embodiments will be described in detail.

[0063] Example 2

[0064] A second specific embodiment of the multi-section combined reactor of the present invention, as follows: Figure 3 As shown, the main technical solution of this embodiment is the same as that of Embodiment 1. Features not explained in this embodiment are explained using the methods in Embodiment 1, and will not be repeated here. The difference between this embodiment and Embodiment 1 is that there are two circulation units, which are connected in series. The stirred reaction zone 2 is arranged in the descending section. When the stirred reaction zone 2 is located in the middle of the reactor, it is easy to integrate it with the mounting support of the straight sleeve 11, achieving a lightweight design and reducing costs. There are multiple upper and lower circulation loops. The features are: the straight sleeves 11 have the same structure, and multiple pairs of upright straight sleeves 11 are beneficial to improving the overall structural strength and rigidity of the reactor, and also have high production capacity.

[0065] Example 3

[0066] A third specific embodiment of the multi-section combined reactor of the present invention, such as... Figure 4As shown, the main technical solution of this embodiment is the same as that of Embodiment 2. Features not explained in this embodiment are explained using the methods in Embodiment 2, and will not be repeated here. The difference between this embodiment and Embodiment 2 is that the stirred reaction zone 2 is arranged in the lower bent sleeve 12, and the circulation units before and after the stirred reaction zone 2 are symmetrically arranged. The vessel body 21 of the stirred reaction zone 2 is arranged horizontally. The advantage is that the stirred reaction zone 2 is installed in the position that best improves the natural frequency of the overall structure, avoiding vibration of the overall reactor structure and facilitating stable operation. In addition, the stirring reaction zone 2 is convenient for installation, inspection and maintenance when it is located at the bottom of the reactor.

[0067] Example 4

[0068] The fourth specific embodiment of the multi-section combined reactor of the present invention is as follows: Figure 5 As shown, the main technical solution of this embodiment is the same as that of Embodiment 3. Features not explained in this embodiment are explained using the methods in Embodiment 3, and will not be repeated here. The difference between this embodiment and Embodiment 3 is that the vessel body 21 of the stirred reaction zone 2 is arranged vertically. Its advantages are: flexibility and versatility, depending on the needs of the process.

[0069] Example 5

[0070] The fifth specific embodiment of the multi-section combined reactor of the present invention, such as... Figure 6 As shown, the main technical solution of this embodiment is the same as that of embodiment 2. Features not explained in this embodiment are explained in embodiment 2 and will not be repeated here. The difference between this embodiment and embodiment 2 is that the stirred reaction zone 2 is installed on the straight sleeve 11, which serves as the rising section.

[0071] Example 6

[0072] The sixth specific embodiment of the multi-section combined reactor of the present invention, as follows: Figure 7 As shown, the main technical solution of this embodiment is the same as that of Embodiment 1. Features not explained in this embodiment are explained in Embodiment 1 and will not be repeated here. The difference between this embodiment and Embodiment 1 is that there are two serial tube reaction zones 1. The vessel body 21 of the same stirred reaction zone 2 is connected to the central flow channel of the two serial tube reaction zones 1, and the vessel jacket flow channel 22 of the same stirred reaction zone 2 is connected to the outer ring flow channel of the two serial tube reaction zones 1.

[0073] When the production capacity of the stirred reaction zone 2 is significantly larger than that of the serial tube reaction zone 1, the reactor as a whole can be designed as a stirred reaction zone 2 with two pairs of inlets and outlets, which are respectively connected to different serial tube reaction zones 1, forming a closed-loop dual-loop reactor. The two loops can operate simultaneously, or one loop can be started while the other is stopped.

[0074] In the description of this invention, it is obvious that the described embodiments are merely a part of the embodiments of the invention, and not all of them. The components of the embodiments of the invention described and illustrated herein can generally be arranged and designed in various different configurations.

[0075] Therefore, the above detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0076] In the description of this invention, it should be noted that the terms "middle," "upper," "lower," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0077] Furthermore, terms such as "horizontal" and "vertical" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0078] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "set," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection. They can refer to a mechanical connection or an electrical connection. They can refer to a direct connection or an indirect connection through an intermediate medium, or a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

Claims

1. A multi-section combined reactor, characterized by: The system includes a series-tube reaction zone and a stirred reaction zone. The series-tube reaction zone includes straight tubes, bent tubes, and a jacketed connecting tube. The straight tubes include an inner tube and an outer tube arranged vertically, with the inner tube passing through the outer tube to form an annular straight jacketed flow channel. Each bent tube includes an outer bend and an inner bend, with the outer bend fitting over the inner bend to form an annular bent jacketed flow channel. The inner tubes of different straight tubes are connected in series through the inner bends to form a central flow channel for transporting reactants and for the reaction. Both ends of the straight jacketed flow channel and the bent jacketed flow channel are respectively provided with sealing structures to seal the two ports of the straight jacketed flow channel and the two ports of the bent jacketed flow channel. The straight jacketed flow channel and the bent jacketed flow channel are connected in series through the jacketed connecting tube to form an outer annular flow channel for transporting cooling medium. The stirred reaction zone includes a vessel body, a vessel jacket flow channel located outside the vessel body, and a stirrer inserted into the vessel body. A connection zone is formed by partially reducing the length of the straight and / or bent sections of the pipe in the serial reaction zone. The vessel body is located at the connection zone. The inlet and outlet of the vessel body are connected via a main valve to the interface formed by the reduction of sections in the central flow channel, thus making the vessel body a partial section of the central flow channel. The inlet and outlet of the vessel jacket flow channel are connected via a secondary valve to the interface formed by the reduction of sections in the outer ring flow channel, thus making the vessel jacket flow channel a partial section of the outer ring flow channel.

2. The multi-section combined reactor according to claim 1, characterized in that: The curved jacket flow channel is provided with a first flange at each end for connecting the end of the straight jacket flow channel.

3. The multi-section combined reactor according to claim 1, characterized in that: The interface formed by the removal of straight and / or bent sleeves is provided with a second flange for connecting the vessel body.

4. The multi-section combined reactor according to claim 1, characterized in that: Each pair of straight sleeves in the serial tube reaction zone and the connected bent sleeve form a circulation unit, and the straight sleeve is divided into an ascending section and a descending section according to the flow direction of the medium inside. The ascending section located on the outermost side is connected to the feed pipe, and the descending section located on the outermost side is connected to the discharge pipe.

5. The multi-section combined reactor according to claim 4, characterized in that: The number of circulation units is one, the feed pipe is connected to the lower end of the rising section, the discharge pipe is connected to the lower end of the falling section, and the stirring reaction zone is arranged in the falling section, the rising section and / or the bend.

6. The multi-section combined reactor according to claim 4, characterized in that: The number of the circulation units is two or more, and they are connected in series. The stirred reaction zone is arranged in the descending section, the ascending section and / or the bend sleeve.

7. The multi-section combined reactor according to claim 6, characterized in that: The stirred reaction zone is located in the lower bent sleeve, and the circulation units before and after the stirred reaction zone are symmetrically arranged.

8. The multi-section combined reactor according to claim 4, characterized in that: The number of serial tube reaction zones is two or more. The vessel body of the same stirred reaction zone is simultaneously connected to the central flow channels of two or more serial tube reaction zones, and the vessel jacket flow channel of the same stirred reaction zone is simultaneously connected to the outer ring flow channels of two or more serial tube reaction zones.

9. The multi-section combined reactor according to claim 1, characterized in that: The stirred reaction zone is also equipped with a normally closed spare material port connecting to the vessel body and a spare cooling port connecting to the vessel jacket flow channel.

10. The multi-section combined reactor according to any one of claims 1 to 9, characterized in that: The agitator is arranged coaxially with the vessel body, which can be arranged horizontally or vertically.

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