Pressure self-balancing five-section independent temperature control fixed bed reaction system and reaction method

Abstract

The invention discloses a pressure self-balancing five-section independent temperature control fixed bed reaction system and a reaction method, and belongs to the technical field of chemical exothermic reaction. According to the system, a reactor shell pass is divided into five sections of independent reaction bed layers through an upper tube plate, a four-stage middle tube plate and a lower tube plate, each bed layer is provided with a temperature control unit for double-loop heating medium circulation and a pressure self-balancing unit controlled by a proportional-integral control valve and a branch regulating valve in a cascade connection mode, and a down tube is of a reducing structure and is provided with a Venturi flow controller. The middle tube plate is provided with a spiral flow deflector. According to the reaction method, the temperature of a reaction bed and the flow of a heat exchange medium are independently adjusted through the temperature control unit and the pressure self-balancing unit, so that two temperature control modes of isothermal temperature and gradient are realized. The multi-section reactor solves the technical problems that the airspeed is influenced due to overlarge pressure drop of a lower-section bed layer and the overall temperature coupling is difficult to independently and accurately regulate and control because a single pressure system is adopted by the multi-section reactor in the prior art.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical exothermic reactions, and in particular relates to a pressure-self-balancing five-stage independent temperature-controlled fixed-bed reaction system, and also relates to a pressure-self-balancing five-stage independent temperature-controlled fixed-bed reaction method. Background Art

[0002] For some exothermic reactions with large heat effects, there are significant hot spots in the catalyst bed. Local overheating is prone to occur in the reaction bed, and heat removal is not timely and sufficient, leading to side reactions. Improper operation may even cause temperature runaway. In order to remove the reaction heat in time, this type of reaction process usually uses a shell-and-tube fixed bed reactor.

[0003] Traditional fixed-bed reactors suffer from problems such as uneven axial temperature distribution and catalyst deactivation caused by accumulated pressure drop. It is well known that reactor pressure is a key factor in continuous flow chemical reactions, requiring constant pressure control under a variety of harsh conditions. Prior art multi-stage reactors typically use a single pressure system, resulting in excessive pressure drop in the lower bed layer, which affects the air velocity. Furthermore, the overall temperature coupling is difficult to independently and accurately control. The present invention effectively solves these problems through graded pressure compensation and a modular temperature control system. Summary of the Invention

[0004] The purpose of the present invention is to provide a five-stage independent temperature-controlled fixed-bed reaction system with self-balanced pressure, which solves the technical problems of uneven axial temperature distribution and catalyst deactivation caused by accumulated pressure drop in traditional fixed-bed reactors.

[0005] The first technical solution adopted by the present invention is a pressure self-balancing five-stage independent temperature-controlled fixed-bed reaction system, including a reactor, the reactor including a vertically arranged cylinder; the top end of the cylinder is connected to an upper head, the upper head is provided with a raw gas inlet; the bottom end of the cylinder is connected to a lower head, the lower head is provided with a product outlet; the inner wall of the cylinder is sealed and connected with an upper tube plate, a fourth-stage intermediate tube plate and a lower tube plate along the axial direction from top to bottom; the upper tube plate, the fourth-stage intermediate tube plate and the lower tube plate divide the shell side into five reaction bed layers; a reaction tube is provided between the upper tube plate and the lower tube plate, which passes through the five reaction bed layers, and each reaction bed layer is connected to a temperature control unit and a pressure self-balancing unit; the temperature control unit and the pressure self-balancing unit are connected to a heat medium storage tank.

[0006] The first technical solution of the present invention is also characterized in that: Each reaction bed adopts double-loop heat medium circulation, which includes a lower loop and an upper loop.

[0007] The temperature control unit includes a first circuit and a second circuit connected in parallel, the first circuit is provided with a circulation pump, and the second circuit is provided with a cooler; The temperature control unit also includes a third circuit, on which an electric heater is provided; The first loop and the third loop are both connected to the double loop.

[0008] The inlet of the circulation pump is connected to the upper ring channel through the first circuit, and the outlet of the circulation pump is connected to the lower ring channel through the first circuit; the inlet of the electric heater is connected to the lower ring channel through the third circuit, and the outlet of the electric heater is connected to the upper ring channel through the third circuit.

[0009] The pressure self-balancing unit includes a proportional integral control valve, the inlet of the proportional integral control valve is connected to the outlet of the heat medium storage tank, and five regulating valves are connected in parallel to the outlet of the proportional integral control valve. The five regulating valves are respectively set on five second circuits.

[0010] The bottom of the shell side of each reaction bed is connected to the inlet end of the heat medium storage tank through a downpipe. The diameter of the upper section of the downpipe is larger than that of the lower section. A venturi throttle is installed at the inlet end of the downpipe.

[0011] Spiral guide vanes are provided between the four intermediate tube plates and the adjacent lower annular channels.

[0012] The heat medium in the heat medium storage tank is any one of thermal oil, water and molten salt.

[0013] The second technical solution adopted by the present invention is a pressure self-balancing five-stage independent temperature-controlled fixed-bed reaction method, which adopts the above-mentioned pressure self-balancing five-stage independent temperature-controlled fixed-bed reaction system, comprising the following steps: S1: Feeding the raw gas into the reactor and allowing it to flow through each reaction bed to undergo catalytic reaction; S2: The temperature is independently adjusted by the temperature control unit corresponding to each reaction bed; S3: Regulate the flow of heat exchange medium in each bed through the pressure self-balancing unit; S4: Switch the reaction bed section combination or temperature control mode according to process requirements, and adjust the pressure balance parameters simultaneously.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The present invention divides the shell side into five independent reaction beds, each of which is equipped with an independent temperature control unit to achieve isothermal or gradient temperature control mode, accurately regulate the temperature of each bed, avoid side reactions and temperature runaway risks caused by local overheating, and is particularly suitable for hot spot control in exothermic reactions; the pressure self-balancing unit dynamically adjusts the flow rate of heat exchange medium in each bed through the cascade control of the proportional integral control valve and five branch regulating valves, compensates for the bed pressure drop, maintains a stable air velocity, and extends the service life of the catalyst; the downpipe adopts a variable diameter structure in which the upper section has a larger diameter than the lower section, and a Venturi throttle is installed at the inlet end, which cooperates with the spiral guide vanes at the intermediate tube plate and the bottom of the reaction bed to reduce the system pressure loss and the energy consumption of the circulation pump, while guiding the gas to diffuse evenly and improve the reaction uniformity. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic structural diagram of the pressure self-balancing five-stage independent temperature-controlled fixed-bed reaction system of the present invention; Figure 2 It is a schematic flow diagram of the pressure self-balancing five-stage independent temperature-controlled fixed bed reaction method of the present invention.

[0016] In the figure, 1. upper head, 2. cylinder, 3. upper tube sheet, 4. spiral guide vane, 5. intermediate tube sheet I, 6. intermediate tube sheet II, 7. intermediate tube sheet III, 8. intermediate tube sheet IV, 9. downcomer, 10. lower tube sheet, 11. lower head, 12. lower annular channel, 13. upper annular channel, 14. proportional-integral control valve, 15. reactor, 16. heat medium storage tank, 17. regulating valve, 18. circulating pump, 19. cooler, 20. electric heater, 21. reaction tube. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0018] Example 1 like Figure 1 As shown, the pressure-self-balancing five-stage independent temperature-controlled fixed-bed reaction system disclosed in this embodiment includes a reactor 15, which comprises a vertically arranged cylinder 2. The top end of the cylinder 2 is connected to an upper end cap 1, which is provided with a feed gas inlet. The bottom end of the cylinder 2 is connected to a lower end cap 11, which is provided with a product outlet. The inner wall of the cylinder 2 is sealed and spaced axially from top to bottom with an upper tube sheet 3, a fourth intermediate tube sheet, and a lower tube sheet 10. The upper tube sheet 3, the fourth intermediate tube sheet, and the lower tube sheet 10 divide the shell side into five reaction beds. Reaction tubes 21 are provided between the upper tube sheet 3 and the lower tube sheet 10, extending through the five reaction beds. Each reaction bed is connected to a temperature control unit and a pressure-self-balancing unit. The temperature control unit and the pressure-self-balancing unit are connected to a heat medium storage tank 16. The four intermediate tube sheets, in descending order, are: intermediate tube sheet I5, intermediate tube sheet II6, intermediate tube sheet III7, and intermediate tube sheet IV8.

[0019] In this embodiment, the cylinder 2 serves as the main structure of the reactor 15, and is vertically arranged to provide a reaction space. Its inner wall is sealed to connect the upper tube sheet 3, the fourth-stage intermediate tube sheet and the lower tube sheet 10, and the shell side is divided into five independent areas to ensure that the heat exchange medium of each bed layer does not flow into each other and maintain an independent reaction environment. The top of the upper head 1 is sealed to the cylinder 2 and is provided with a raw gas inlet. Its main function is to guide the raw gas to enter the reactor evenly while ensuring gas sealing to prevent leakage. The bottom end of the lower head 11 is sealed to the cylinder 2 and is provided with a product outlet for collecting and exporting the products after the reaction, which also plays a sealing and diversion role. The heat medium storage tank 16 serves as a storage and circulation hub for the heat medium. It stores the corresponding heat medium according to the reaction requirements, and is connected to the temperature control unit, the pressure self-balancing unit and each reaction bed through a pipeline to ensure that the heat medium can circulate continuously. The upper tube sheet 3, the fourth-stage intermediate tube sheet, and the lower tube sheet 10 are spaced apart along the axial direction of the cylinder 2 and are sealed to the inner wall of the cylinder 2. On the one hand, they support the reaction tubes 21, and on the other hand, they divide the shell side into five independent reaction beds, ensuring that the heat exchange medium circulates independently in each bed without interfering with each other, providing a structural basis for independent temperature control and pressure balance.

[0020] This embodiment constructs the basic framework of a five-stage, independently temperature-controlled fixed-bed reaction system with self-balancing pressure. By dividing the shell side into five independent reaction beds, refined control of the reaction process can be achieved. Different beds can be loaded with catalysts with different characteristics and set different reaction temperature and pressure conditions, thereby accurately regulating the reaction process. At the same time, each bed is independently connected to a temperature control unit and a pressure self-balancing unit to avoid interference between stages, maintain a stable reaction environment, and extend the service life of the catalyst. In addition, by connecting to the heat medium storage tank 16, the heat exchange medium can be recycled, improving energy utilization and reducing operating costs.

[0021] Example 2 On the basis of Example 1, each reaction bed layer adopts a double-loop heat medium circulation, and the double loop includes a lower loop 12 and an upper loop 13 .

[0022] The temperature control unit includes a first circuit and a second circuit connected in parallel, the first circuit is provided with a circulation pump 18, and the second circuit is provided with a cooler 22; The temperature control unit further comprises a third circuit, on which an electric heater 20 is provided; The first loop and the third loop are both connected to the double loop.

[0023] The inlet end of the circulation pump 18 is connected to the upper ring channel 13 through the first circuit, and the outlet end of the circulation pump 18 is connected to the lower ring channel 12 through the first circuit; the inlet end of the electric heater 20 is connected to the lower ring channel 12 through the third circuit, and the outlet end of the electric heater 20 is connected to the upper ring channel 13 through the third circuit.

[0024] In this embodiment, a circulating pump 18 is installed in the first loop, providing power for the circulation of the heat exchange medium between the reaction bed and the temperature control unit, ensuring continuous flow and maintaining efficient heat exchange. Its flow rate range can be dynamically adjusted according to reaction requirements. Its inlet connects to the upper loop 13 through the first loop, and its outlet connects to the lower loop 12, forming a top-down flow path for the medium. During an exothermic reaction, this flow pattern preferentially removes heat from the high-temperature areas of the bed, enhancing heat dissipation. A cooler 22 is located in the second loop. When the reaction bed temperature is too high, cooler 22 activates to cool the circulating heat exchange medium, transferring heat to an external cooling source, thereby lowering the reaction bed temperature. Its cooling power is automatically adjusted based on temperature feedback, achieving precise temperature control. An electric heater 20 is located in the third loop. When the reaction bed temperature falls below a set value, it activates to heat the heat exchange medium to replenish the heat required for the reaction. Its inlet connects to the lower loop 12 through the third loop, and its outlet connects to the upper loop 13, achieving countercurrent heating of the heat exchange medium. In the endothermic reaction, the low-temperature medium enters the electric heater 20 from the lower loop 12 and returns to the bed from the upper loop 13 after being heated.

[0025] In this embodiment, precise bidirectional control of the reaction bed temperature is achieved by interconnecting the first, second, and third circuits in parallel. During exothermic reactions, excess heat is quickly removed by the cooler 22 in the second circuit, preventing excessive bed temperatures from deactivating the catalyst. During endothermic reactions, the electric heater 20 in the third circuit promptly replenishes the required heat, ensuring a continuous and stable reaction.

[0026] Example 3 On the basis of Example 2, the pressure self-balancing unit includes a proportional-integral control valve 14, the inlet end of the proportional-integral control valve 14 is connected to the outlet end of the heat medium storage tank 16, and five regulating valves 17 are connected in parallel to the outlet end of the proportional-integral control valve 14. The five regulating valves 17 are respectively arranged on five second circuits.

[0027] In this embodiment, the inlet of the proportional-integral control valve 14 is connected to the outlet of the heat medium storage tank 16, and five branch pipelines are connected in parallel to the outlet. The proportional-integral control valve acts as a total flow regulator, monitoring the pressure data of the five bed layers in real time, and dynamically adjusting the total flow rate according to the pressure deviation through the proportional-integral algorithm. The response time is less than 10 seconds, ensuring a stable medium supply to each bed layer. The branch regulating valves 17 are respectively arranged on the five second loops, and each branch regulating valve corresponds to a reaction bed layer. Its function is to independently adjust the medium flow of the corresponding bed layer according to the instructions of the proportional-integral control valve, with an adjustment accuracy of up to ±3%, and to achieve pressure balance of each bed layer by precisely controlling the flow rate.

[0028] This embodiment achieves precise distribution of the heat exchange medium flow rate to each reaction bed through cascade control of the proportional-integral control valve 14 and the five branch regulating valves 17, thereby maintaining system pressure balance. When the pressure of a bed fluctuates, the proportional-integral control valve 14 quickly adjusts the total flow rate based on the pressure average of the five bed sections, and each branch regulating valve 17 synchronously fine-tunes the flow rate ratio of the corresponding bed to control the pressure difference between each bed within ±10kPa. This dynamic adjustment mechanism gives the system strong anti-interference capabilities. When the reaction load fluctuates by ±20%, the pressure stabilization time is less than 2 minutes. In addition, the design also supports flexible switching of the number of reaction bed sections (such as 2-5 sections). During the switching process, the pressure fluctuation is controlled within ±15%, ensuring the continuity and stability of the reaction process.

[0029] Example 4 On the basis of Example 3, the bottom of each lower ring channel 12 is connected to the inlet end of the heat medium storage tank 16 through a descending pipe 9. The upper diameter of the descending pipe 9 is larger than the lower diameter. A Venturi throttle is installed at the inlet end of the descending pipe 9.

[0030] In this embodiment, the Venturi restrictor is installed at the inlet end of the downpipe 9. When the heat exchange medium flows through the Venturi restrictor, the throat diameter is reduced to produce a local pressure drop, and the shell side pressure is adjusted by the pressure difference.

[0031] In this embodiment, the descending pipe 9 utilizes a variable diameter structure with a larger upper diameter than the lower section. This, combined with a Venturi restrictor at the inlet, significantly reduces system pressure loss. Compared to pipes of equal diameter, this reduces pressure loss and reduces energy consumption in the circulating pump. The variable diameter structure utilizes gravity to allow the heat exchange medium to descend smoothly, avoiding eddies and pressure losses caused by sudden changes in flow rate. The Venturi restrictor automatically adjusts the shell-side pressure through its localized resistance effect. This allows it to quickly compensate for pressure fluctuations when the medium flow rate changes, improving system pressure stability.

[0032] Example 5 On the basis of Example 4, spiral guide vanes 4 are provided between the four intermediate tube plates and the adjacent lower annular channels 12 .

[0033] Spiral guide vanes 4 are installed between the four intermediate tube sheets and the adjacent lower annulus 12, with their outer edges sealed to the inner wall of the cylinder 2. As gas flows through spiral guide vanes 4, guided by the spiral structure, it undergoes rotational motion, converting some of its kinetic energy into pressure energy, compensating for bed pressure drop. Simultaneously, the guide vanes force the gas to diffuse evenly across the entire bed cross-section, improving reaction uniformity.

[0034] Example 6 Based on any of the above embodiments, the heat medium in the heat medium storage tank 16 is any one of thermal oil, water and molten salt.

[0035] Different heat media are suitable for reactions in different temperature ranges: water is suitable for low-temperature reactions (≤200°C), and the steam generated by its vaporization can be further used to preheat feedstock, achieving cascaded energy utilization and improving energy efficiency. Molten salt is suitable for high-temperature reactions (300-500°C), featuring high thermal conductivity and good thermal stability, meeting the rapid heat transfer requirements of high-temperature reactions. Thermal oil is suitable for medium-temperature reactions (100-300°C), where its excellent fluidity and thermal conductivity ensure temperature stability. By flexibly selecting heat media, the system can adapt to various reaction processes such as hydrogenation, reforming, and cracking, broadening its application range.

[0036] like Figure 2 As shown, the present invention also discloses a pressure self-balancing five-stage independent temperature-controlled fixed bed reaction method, which uses the pressure self-balancing five-stage independent temperature-controlled fixed bed reaction system described in the above embodiment, including the following steps: S1: Feeding the raw gas into the reactor 15, so that it flows through each reaction bed to perform a catalytic reaction; S2: The temperature is independently adjusted by the temperature control unit corresponding to each reaction bed, supporting isothermal or gradient temperature control mode; S3: Regulate the flow of heat exchange medium in each bed through the pressure self-balancing unit; S4: Switch the reaction bed section combination or temperature control mode according to process requirements, and adjust the pressure balance parameters simultaneously.

[0037] Switching the reaction bed temperature control mode is as follows: In isothermal mode, the temperature regulating device controlling each reaction bed maintains the corresponding bed temperature at the same set value; In the gradient mode, the temperature regulating device controlling each reaction bed maintains the temperature of the corresponding bed at different set values, forming a temperature gradient that increases or decreases along the flow direction of the reactants.

[0038] In summary, the present invention is applicable to catalytic reaction processes that are sensitive to temperature gradients, such as hydrogenation, reforming, and Fischer-Tropsch synthesis, such as the catalytic oxidation of hydrogen chloride to produce chlorine, diesel hydrofining, and carbon dioxide methanation. The following provides specific application examples in conjunction with the reaction systems disclosed in Examples 1-6 and the above-mentioned reaction method: Example 7: Preparation of 1,2-butylene oxide The reaction raw materials are introduced into the reactor tube at a mass flow rate of 600 kg / h, the molar ratio of 1-butene to isopropylbenzene hydroperoxide is 1:0.5, the pressure is 2-5 MPa, and the temperature is 60-90°C. Figure 1As shown, the reaction is carried out in five sections and two zones. Sections I-III have identical reaction conditions and are loaded with Catalyst I; Sections IV-V have identical reaction conditions and are loaded with Catalyst II. Water is used as the heat transfer medium, and the reactor shell is divided into three zones. The bed temperature in the first section is maintained at 30-85°C; the second section at 30-90°C; and the third section at 30-95°C.

[0039] Example 8: Preparation of 1,2-butylene oxide The reaction raw materials are introduced into the reactor tube at a mass flow rate of 800 kg / h, the molar ratio of 1-butene to isopropylbenzene hydroperoxide is 1:0.4, the pressure is 2-5 MPa, and the temperature is 90-100°C. Figure 1 As shown, the reaction is carried out in five sections and three zones. Sections I and II have the same reaction conditions and are loaded with catalyst I; sections III and IV have the same reaction conditions and are loaded with catalyst II; and section V is loaded with catalyst III. Thermal oil is used as the heat transfer medium. The reactor shell is divided into three zones, maintaining the bed temperature in the first section at 60-100°C; the second section at 60-120°C; and the third section at 70-130°C.

[0040] Example 9: Preparation of 1,2-butylene oxide The reaction raw materials are introduced into the reactor tube at a mass flow rate of 1000 kg / h, the molar ratio of 1-butene to isopropylbenzene hydroperoxide is 1:0.6, the pressure is 2-5 MPa, and the temperature is 100-130°C. Figure 1 As shown, the reactor uses five sections and four zones for the reaction. Section I is loaded with Catalyst I; Section II is loaded with Catalyst II; Section III is loaded with Catalyst III; and Sections IV-V, under the same reaction conditions, are loaded with Catalyst IV. Thermal oil is used as the heat transfer medium. The reactor shell is divided into four zones, maintaining the bed temperature at 70-120°C in the first section, 70-130°C in the second section, 70-140°C in the third section, and 70-150°C in the fourth section.

[0041] Finally, it should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or device comprising the element.

[0042] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0043] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present application. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A five-stage independent temperature-controlled fixed-bed reaction system with self-balanced pressure, characterized by: The reactor (15) comprises a vertically arranged cylinder (2); the top end of the cylinder (2) is connected to an upper head (1), and the upper head (1) is provided with a raw gas inlet; the bottom end of the cylinder (2) is connected to a lower head (11), and the lower head (11) is provided with a product outlet; the inner wall of the cylinder (2) is sealed and connected to an upper tube plate (3), a fourth-stage intermediate tube plate, and a lower tube plate (10) in an axial direction from top to bottom; the upper tube plate (3), the fourth-stage intermediate tube plate, and the lower tube plate (10) divide the shell side into five sections of reaction beds; a reaction tube (21) penetrating the five sections of reaction beds is provided between the upper tube plate (3) and the lower tube plate (10), and each section of the reaction bed is connected to a temperature control unit and a pressure self-balancing unit; the temperature control unit and the pressure self-balancing unit are connected to a heat medium storage tank.

2. The pressure self-balancing five-stage independent temperature-controlled fixed-bed reaction system according to claim 1 is characterized in that: Each reaction bed layer adopts a double-loop heat medium circulation, and the double loop includes a lower loop (12) and an upper loop (13).

3. The pressure self-balancing five-stage independent temperature-controlled fixed-bed reaction system according to claim 2, characterized in that: The temperature control unit comprises a first circuit and a second circuit connected in parallel, the first circuit is provided with a circulation pump (18), and the second circuit is provided with a cooler (22); The temperature control unit further includes a third circuit, on which an electric heater (20) is provided; The first loop and the third loop are both connected to the double loop.

4. The pressure self-balancing five-stage independent temperature-controlled fixed-bed reaction system according to claim 3 is characterized in that: The inlet end of the circulation pump (18) is connected to the upper ring channel (13) through the first loop, and the outlet end of the circulation pump (18) is connected to the lower ring channel (12) through the first loop; the inlet end of the electric heater (20) is connected to the lower ring channel (12) through the third loop, and the outlet end of the electric heater (20) is connected to the upper ring channel (13) through the third loop.

5. The pressure self-balancing five-stage independent temperature-controlled fixed-bed reaction system according to claim 4 is characterized in that: The pressure self-balancing unit includes a proportional integral control valve (14), the inlet end of the proportional integral control valve (14) is connected to the outlet end of the heat medium storage tank (16), and five regulating valves (17) are connected in parallel to the outlet end of the proportional integral control valve (14), and the five regulating valves (17) are respectively arranged on five second circuits.

6. The pressure self-balancing five-stage independent temperature-controlled fixed-bed reaction system according to claim 5, characterized in that: The bottom of each lower annular channel (12) is connected to the inlet end of the heat medium storage tank (16) through a descending pipe (9). The diameter of the upper section of the descending pipe (9) is larger than the diameter of the lower section. A Venturi throttle is installed at the inlet end of the descending pipe (9).

7. The pressure self-balancing five-stage independent temperature-controlled fixed-bed reaction system according to claim 6, characterized in that: Spiral guide vanes (4) are provided between the four intermediate tube plates and the adjacent lower annular channels (12).

8. The pressure self-balancing five-stage independent temperature-controlled fixed-bed reaction system according to any one of claims 1 to 7, characterized in that: The heat medium in the heat medium storage tank (16) is any one of heat transfer oil, water and molten salt.

9. A pressure self-balancing five-stage independent temperature-controlled fixed-bed reaction method, using the pressure self-balancing five-stage independent temperature-controlled fixed-bed reaction system according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1: introducing the raw gas into the reactor (15) and allowing it to flow through each reaction bed to undergo a catalytic reaction; S2: The temperature is independently adjusted by the temperature control unit corresponding to each reaction bed; S3: Regulate the flow of heat exchange medium in each bed through the pressure self-balancing unit; S4: Switch the reaction bed section combination or temperature control mode according to process requirements, and adjust the pressure balance parameters simultaneously.

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