An esterification reactor pressure regulating device specially customized for a three-kettle process

Abstract

The utility model discloses a kind of esterification reactor pressure regulation and control devices specially customized for three-kettle process, bubble cap intercepting valve includes air outlet short pipe II, bubble cap, intercepting sleeve, guide sleeve, lifting rod and support;Air outlet short pipe II is connected at the top of evaporator, and is connected with bubble cap by support pipe, intercepting sleeve is sleeved in the outside of air outlet short pipe II, intercepting sleeve is inserted into bubble cap, and bubble cap top end surface and bubble cap inner wall are all left with gap between intercepting sleeve, lifting mechanism is connected on intercepting sleeve, pass through lifting mechanism to drive intercepting sleeve up and down to move to adjust the flow area between intercepting sleeve and bubble cap top end surface, to realize the accurate regulation and control to esterification reactor internal pressure, with the technical features of being able to effectively adjust and stabilize the pressure inside reactor, ensure that reaction process is carried out in the set pressure range etc.

Description

Technical Field

[0001] This utility model relates to a pressure control device, and more specifically, to a pressure control device for an esterification reactor specifically designed for a three-reactor process, belonging to the field of polyester production. Background Technology

[0002] The primary goal of the esterification process is to achieve an esterification rate that meets the standards for polycondensation processes. Esterification is a reversible equilibrium process, meaning that under specific operating conditions, there exists a maximum achievable esterification rate, known as the equilibrium esterification rate. Among the various parameters of the esterification reaction, pressure control is particularly important while maintaining other conditions constant. Appropriate pressure settings not only promote the reaction rate but also ensure the effective removal of water generated during the reaction, driving the reaction towards esterification. However, when the reaction pressure increases, it hinders water escape, weakens the driving force of the forward esterification reaction, and thus slows down the reaction rate. Simultaneously, a high-pressure environment increases the concentration of free ethylene glycol (EG) in the reaction solution, increasing the risk of generating byproducts (such as BEG). Conversely, if the pressure setting is too low, the evaporation rate of ethylene glycol will increase sharply, leading to entrainment into the process tower, which not only causes material loss but also threatens the stable operation of the plant.

[0003] Therefore, the esterification stage is usually carried out under slightly positive pressure conditions, and the pressure inside the reactor needs to be maintained between about 0.13 and 0.15 MPa. This pressure setting is designed to carefully balance the relationship between reaction rate, product selectivity and energy consumption in order to optimize the esterification effect.

[0004] Currently, the esterification reactor design used in DuPont's three-reactor polyester process integrates an external tube heater and evaporator. The bottom of the heater is connected to the evaporator via a U-tube, while its top is connected to the lower part of the evaporator via a short pipe, forming a highly efficient structure with the heater and evaporator connected in series. A gas phase outlet is located at the top of the evaporator, which is fixedly connected to a cylindrical bubble cap via a short pipe. However, this structure has the following drawbacks: the short pipe and the cylindrical bubble cap are in relatively fixed positions, preventing the adjustment of the internal pressure of the esterification reactor; and the vapor separator is directly installed at the top of the evaporator and communicates with the reactor interior via the gas phase outlet short pipe and the cylindrical bubble cap.

[0005] Therefore, the existing design allows the material to circulate between the heater and the evaporator. During the reaction, the generated water and ethylene glycol enter the evaporator together for removal. The generated water and ethylene glycol (EG) can flow through the gas phase outlet short pipe and be diverted into the separation tower under the action of the bubble cap, thereby achieving efficient separation.

[0006] In customized esterification reactors with a three-reactor process, a high molar ratio is typically used, resulting in a large amount of free ethylene glycol (EG) inside the reactor, leading to high evaporation rates. This causes the generated water vapor and ethylene glycol vapor to carry large amounts of PTA and esterified compounds into the separation tower, severely impacting its separation efficiency. In extreme cases, these impurities may clog the EG pipeline, causing an abnormal rise in the liquid level inside the separation tower, ultimately preventing the unit from maintaining normal operation. Utility Model Content

[0007] To address the aforementioned technical problems, this invention provides a pressure control device specifically designed for a three-reactor process esterification reactor, featuring the ability to effectively regulate and stabilize the internal pressure of the reactor, ensuring that the reaction process proceeds within a set pressure range.

[0008] To achieve the above objectives, this utility model is implemented through the following technical solution:

[0009] This utility model discloses a pressure control device for an esterification reactor specifically designed for a three-reactor process. It includes a heater, an evaporator, a U-tube, a short pipe I, a separation tower, and a bubble cap shut-off valve. The bottom of the evaporator is connected to the bottom of the heater through the U-tube, and the lower part of the evaporator is connected to the upper part of the heater through the short pipe I. A bubble cap shut-off valve is connected between the evaporator and the separation tower. The bubble cap shut-off valve includes an outlet short pipe II, a bubble cap, a shut-off sleeve, a guide sleeve, a lifting rod, and a support.

[0010] The outlet short pipe II is connected to the top of the evaporator and connected to the bubble cap via a support pipe. The intercepting sleeve is fitted outside the outlet short pipe II and extends into the bubble cap. There are gaps between the top surface of the bubble cap and the inner wall of the bubble cap and the intercepting sleeve. A lifting mechanism is connected to the intercepting sleeve. The lifting mechanism drives the intercepting sleeve to move up and down to adjust the flow area between the intercepting sleeve and the top surface of the bubble cap, so as to achieve precise control of the internal pressure of the esterification reactor.

[0011] Preferably, the lifting mechanism includes a transmission screw, a transmission nut, a bearing seat, a rocker arm, a connecting frame, and two connecting rods. The transmission screw is connected to a drive shaft via a transmission flange I. The drive shaft is connected to a drive shaft assembly. The transmission screw is a left- or right-handed trapezoidal screw, with a left-handed thread at one end and a right-handed thread at the other end. It passes through a fixed ring in the middle, and the fixed ring is connected to a support. Both the left and right parts of the transmission screw are threaded with a transmission nut. A connecting rod passes through each transmission nut and is perpendicular to the transmission screw. The two connecting rods are hinged to the connecting frame at the same end via a rocker arm. The drive shaft drives the transmission screw to rotate, and the rotation of the transmission screw drives the rocker arm to swing. The rocker arm drives the lifting rod to move up and down. The up and down movement of the lifting rod drives the synchronous movement of the intercepting sleeve to adjust the relative position between the intercepting sleeve and the top surface of the bubble cap, thereby changing the flow area between them.

[0012] Preferably, the connecting frame includes four extension rods forming a square structure, and the ends of the four extension rods are connected to the lifting rod by bolts; the lower end of the rocker arm is sleeved on the head of the extension rod of the connecting frame and is securely connected by rolling bearings and snap rings; when the rocker arm swings, it can drive the entire connecting frame to move up and down, thereby driving the lifting rod to move vertically.

[0013] Preferably, the drive shaft assembly includes a drive shaft and a drive flange II. One end of the drive shaft is connected to the drive shaft through the drive flange II, and the other end of the drive shaft passes through the separation tower and is externally connected to an electric actuator to drive the drive screw to rotate.

[0014] Preferably, the drive shaft is provided with a sealing assembly after passing through the separation tower to prevent it from communicating with the outside after it passes through.

[0015] Preferably, the flow-stopping sleeve has at least two limiting grooves at the bottom, multiple threaded holes at the top, and multiple open slots at the bottom. The lifting rod is connected to the threaded holes of the flow-stopping sleeve by bolts and is guided to move by the guide sleeve at the top of the bubble cap. Multiple support tubes are provided, each corresponding to one of the open slots, to achieve quick positioning and installation of the flow-stopping sleeve. A fixed slider is provided in each limiting groove, and the slider controls the vertical movement range of the flow-stopping sleeve. For example, when the flow-stopping sleeve is at zero stroke, its top is flush with the top of the outlet short pipe II; at maximum stroke, its top is spaced from the inner end face of the bubble cap to ensure normal operation of the equipment.

[0016] Preferably, the lifting rod is round in the middle, square at the top, and semi-cylindrical at the bottom. Both the square rod and the bottom have an axial through hole to accommodate bolt connections (so as to achieve precise alignment with the threaded hole on the upper part of the flow-stopping sleeve and a stable connection via bolts, as well as hinge connection with the lower end of the rocker arm).

[0017] Preferably, the rocker arm is dumbbell-shaped, with rolling bearings at both ends and positioned by snap rings.

[0018] Preferably, the distance between the two middle long rods of the connecting frame is 3 / 4 of the rod length, and the ends of the four extension rods are provided with axial threaded holes.

[0019] Beneficial effects: Significantly improved production efficiency: This device can precisely control the pressure of the esterification reactor, ensuring that the reaction operates within the optimal pressure range, effectively reducing the adverse effects of steam entrainment of materials, and enabling the device output to jump from 900t / d to 960t / d;

[0020] Product quality optimization: Through precise pressure control, side reactions in the esterification reaction are effectively suppressed, ensuring that the quality of the reaction products is more uniform and stable, thereby significantly improving the quality of the products;

[0021] Energy consumption and cost reduction: Precise control of reaction pressure significantly reduces the evaporation of EG, thereby lowering the energy consumption of the esterification reaction. Simultaneously, it reduces the consumption of materials entrained by steam, improves raw material utilization, and effectively reduces production costs.

[0022] Enhanced safety: Precise pressure control reduces the amount of material entrained by steam, lowering the risk of blockage in the separation tower and downstream equipment and pipelines, and providing a higher level of safety for the esterification system;

[0023] Highly automated control: Employing advanced sensors and control systems, the device can monitor pressure changes during the reaction process in real time and automatically adjust to maintain constant pressure, significantly reducing manual intervention and improving production efficiency and stability. Attached Figure Description

[0024] Figure 1 Schematic diagram of the esterification reactor and separation tower assembly.

[0025] Figure 2 One of the structural schematic diagrams of this utility model.

[0026] Figure 3 This is the second schematic diagram of the structure of this utility model.

[0027] Figure 4 This is the third schematic diagram of the structure of this utility model.

[0028] Figure 5 Front view of the blister throttle valve structure.

[0029] Figure 6 Rear view of the blister throttle valve structure.

[0030] Figure 7 Top view of the blister throttle valve structure.

[0031] Figure 8 Front view of the intercepting sleeve structure.

[0032] Figure 9 Top view of the intercepting sleeve structure.

[0033] Figure 10 Schematic diagram of the lifting rod structure.

[0034] Figure 11 Cross-sectional views of the upper, middle, and lower sections of the lifting rod.

[0035] Figure 12 One of the schematic diagrams of the lifting mechanism.

[0036] Figure 13 Second schematic diagram of the lifting mechanism.

[0037] Figure 14 The third schematic diagram of the lifting mechanism.

[0038] Figure 15 Schematic diagram of the transmission lead screw structure.

[0039] Figure 16 Side view of the connecting frame structure.

[0040] Figure 17 Top view of the connecting frame structure.

[0041] Figure 18 One of the schematic diagrams of the transmission nut structure.

[0042] Figure 19 Schematic diagram of the transmission nut structure, part two.

[0043] Figure 20 Schematic diagram of the transmission nut structure, part three.

[0044] Figure 21 Front view of the joystick structure.

[0045] Figure 22 Side view of the joystick structure.

[0046] Figure 23 Schematic diagram of the drive shaft structure. Detailed Implementation

[0047] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0048] In the description of the utility model, it should be noted that the terms "upper", "lower", "inner", "outer", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the device referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the utility model.

[0049] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "setting," "connection," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0050] like Figure 1-23 The diagram illustrates a specific embodiment of a pressure control device for an esterification reactor specifically designed for a three-reactor process. This device effectively regulates and stabilizes the internal pressure of the reactor, ensuring the reaction process proceeds within a set pressure range. It includes: a heater 1, an evaporator 2, a U-shaped tube 3, a short pipe I 4, a separation tower 5, a bubble cap shut-off valve 6, a lifting mechanism 7, a drive shaft 8, and an electric actuator 9.

[0051] The external tube heater 1 and evaporator 2 are perfectly integrated to form a highly efficient, unified structure. The bottom of heater 1 is tightly connected to evaporator 2 via U-shaped tube 3, while the top is smoothly connected to the lower part of evaporator 2 via short tube I 4. A gas phase outlet is cleverly set at the center of the top of evaporator 2. This gas phase outlet is connected to cylindrical bubble cap 6.2 via short outlet tube II 6.1 and a stable support tube, ensuring that the short outlet tube II 6.1 maintains an appropriate gap with the inner end face and inner wall of bubble cap 6.2, thus ensuring smooth airflow.

[0052] A flexible, vertically movable intercepting sleeve 6.3 is cleverly fitted around the outlet short pipe II 6.1 (fixed position). By precisely adjusting the position of the intercepting sleeve 6.3, the flow area between it and the inner end face of the bubble cap 6.2 can be flexibly changed, thereby achieving precise control of the internal pressure of the esterification reactor. One optimized design is that the intercepting sleeve 6.3 is tightly fitted to the outlet short pipe II 6.1 to avoid the flow between them affecting the overall structure. Alternatively, a first circular ring is provided on the inner edge of the lower end of the intercepting sleeve 6.3, and a second circular ring with an outward fold is provided on the upper edge of the outlet short pipe II 6.1. The first circular ring is tightly fitted around the outlet short pipe II 6.1, and the outer edge of the second circular ring is tightly fitted to the inner wall of the intercepting sleeve 6.3, which can ensure the airtightness between the intercepting sleeve 6.3 and the outlet short pipe II 6.1 when the intercepting sleeve 6.3 moves up and down.

[0053] The lower part of the flow-stopping sleeve 6.3 is designed with a limiting groove 6.3.1 to ensure its stroke control. When the flow-stopping sleeve 6.3 is in the 0 stroke position, its top end is horizontally aligned with the top end of the short pipe II 6.1. When the flow-stopping sleeve 6.3 reaches its maximum stroke, a distance is still maintained between its top end and the inner end face of the bubble cap 6.2 to ensure the normal operation of the equipment.

[0054] The intercepting sleeve 6.3 is cleverly designed with several open slots 6.3.2 at the bottom, which makes it easy to slide and fix the intercepting sleeve 6.3 to the outside of the outlet short pipe II 6.1 by simply aligning these open slots with the support pipe during the assembly process.

[0055] The upper part of the flow-stopping sleeve 6.3 is carefully configured with a series of evenly distributed threaded holes 6.3.3 for tightly connecting the lifting rod 6.5 with bolts. The lifting rod 6.5 has a unique design, with a round rod shape in the middle and a square rod shape at the top. A through hole is cleverly opened in the middle of the square rod, and the bottom is designed as a semi-cylindrical shape, also with through holes, to ensure precise alignment with the threaded holes 6.3.3 on the upper part of the flow-stopping sleeve 6.3, and to achieve a secure connection with bolts.

[0056] The top of the blister pack 6.2 is equipped with a precision guide sleeve 6.4 specifically designed for the lifting rod 6.5, ensuring that the lifting rod 6.5 can pass through smoothly and without obstruction. When the choke sleeve 6.3 descends to the lowest working point, the square rod portion of the lifting rod 6.5 can fully extend from the top of the blister pack 6.2, which not only maintains the stability of the overall structure but also greatly facilitates subsequent adjustments and operations.

[0057] The lifting rod 6.5 is securely connected to the lifting mechanism 7 via bolts. The lifting mechanism 7 is stably supported by a bearing housing 7.3 on a support 6.6 located at the center of the top of the bubble cap 6.2. The lifting mechanism 7 consists of several key components, including: a drive screw 7.1, a drive nut 7.2, a bearing housing 7.3, a connecting rod 7.4, a rocker arm 7.5, and a connecting frame 7.6. These components work together to achieve the lifting function.

[0058] The transmission screw 7.1 is designed as a left- or right-hand trapezoidal screw, characterized by a retaining ring 7.1.3 embedded in the middle. One end of the screw has a left-hand thread 7.1.1, and the other end has a right-hand thread 7.1.2. One end of the screw extends into a small-diameter smooth rod, which is externally connected to the transmission flange I 7.1.4. The retaining ring 7.1.3 is assembled inside the bearing housing 7.3, which is securely connected to the support 6.6 at the top of the bubble cap by bolts. Each threaded portion at both ends of the transmission screw 7.1 is connected to a transmission nut 7.2, and these transmission nuts 7.2 are all provided with axially vertical smooth holes, which are positioned exactly below the threaded holes during assembly.

[0059] The transmission nut 7.2 is fitted onto the outer circumference of the connecting rod 7.4 and is located in the middle of the connecting rod 7.4. Rocker arms 7.5, each equipped with rolling bearings, are fitted onto both ends of the connecting rod 7.4. The rocker arms 7.5 are shaped like dumbbells, thicker at both ends and thinner in the middle. Both ends of the rocker arms 7.5 have central holes for housing the rolling bearings, which are positioned by retaining springs at both ends. The ends of the connecting rod 7.4 are secured by bolts to ensure structural stability.

[0060] The other end of the rocker arm 7.5 is fitted onto the head of the extension rod of the connecting frame 7.6. The connecting frame 7.6 has a square structure and is composed of four rods of equal length. Two of the long rods are arranged parallel to each other in the middle of the frame, with a spacing of exactly 3 / 4 of the rod length. The other two long rods are arranged parallel and symmetrically at both ends of the middle long rod, forming the ends of the four parallel extension rods of the connecting frame. Each end of these four extension rods has an axial threaded hole, which facilitates the secure fixing of the lifting rod 6.5 to the four ends with bolts, achieving a tight connection and stable support for the overall structure.

[0061] The drive shaft assembly 8 connected to the lifting mechanism 7 mainly includes a drive shaft 8.1, a transmission flange II 8.2, and a sealing assembly 8.3. The drive shaft 8.1 is designed as a slender rod-like structure, with the transmission flange II 8.2 mounted at one end. This flange is tightly connected to the transmission flange I 7.1.4 at the head of the transmission screw 7.1 by bolts, thus achieving efficient power transmission. The other end of the drive shaft 8.1 is designed as a smooth shaft section with a transmission keyway. This drive shaft 8.1 passes through the tower wall of the separation tower 5 and has a sealing assembly 8.3 installed on the outer wall of the separation tower. Finally, the end of the drive shaft 8.1 extends out of the outer wall of the separation tower and is connected to an external electric actuator 9, enabling remote control and drive.

[0062] Working principle / operation method:

[0063] When the lead screw 7.1 is rotated, its unique left-hand and right-hand trapezoidal thread design allows the two drive nuts 7.2 to move synchronously toward or away from the central bearing seat 7.3. This movement is achieved through the threaded engagement between the lead screw 7.1 and the nuts, ensuring smooth and precise motion.

[0064] As the transmission nuts 7.2 move, they respectively drive the connecting rods 7.4 sleeved in the transmission nuts 7.2 to move, which in turn drives the rocker arms 7.5 at both ends of each connecting rod 7.4 to swing synchronously. The design of the rocker arms 7.5 allows them to swing flexibly in the central position when pushed by the transmission nuts 7.2. This swing is effectively converted into linear motion through the connection between the connecting rods 7.4 and the transmission nuts 7.2.

[0065] The swing of the rocker arm 7.5 is further converted into the up-and-down movement of the lifting rod 6.5. Since the other end of the rocker arm 7.5 is fitted onto the extension rod head of the connecting frame 7.6 and is securely connected by a rolling bearing and a retaining spring, when the rocker arm 7.5 swings, it can drive the connecting frame 7.6 to move up and down as a whole. If the transmission nut 7.2 moves in the opposite direction, it can pull the connecting frame 7.6 upward. When it reaches the limit position, the rocker arm 7.5 and the connecting frame 7.6 are continuously brought closer to being on the same line. Then, the transmission nut 7.2 moves relative to the rocker arm, which can lower the connecting frame 7.6, thereby driving the lifting rod 6.5 to move vertically.

[0066] Ultimately, the up-and-down movement of the lifting rod 6.5 causes the intercepting sleeve 6.3 to move synchronously. The relative position between the intercepting sleeve 6.3 and the inner end face of the bubble cap 6.2 changes, thus altering the flow area between them. This change in flow area directly affects the pressure distribution inside the esterification reactor, allowing operators to precisely control the internal pressure of the esterification reactor by precisely controlling the up-and-down position of the intercepting sleeve 6.3.

[0067] The electric actuator 9 includes a motor and a controller. The electric actuator 9 is interlocked with the pressure inside the reactor. The electric actuator 9 can automatically respond to pressure changes and drive the transmission screw 7.1 to rotate. By rotating the transmission screw 7.1, the flow area between the inner end face of the cut-off sleeve 6.3 and the bubble cap 6.2 is precisely controlled using the principles of threaded engagement, rocker arm swing and linkage transmission, thereby achieving the purpose of precise regulation of the internal pressure of the esterification reactor.

[0068] Finally, it should be noted that this utility model is not limited to the above embodiments, and many variations are possible. All variations that can be directly derived or conceived by those skilled in the art from the disclosure of this utility model should be considered within the protection scope of this utility model.

Claims

1. A pressure control device for an esterification reactor specifically designed for a three-reactor process, characterized in that, The system includes a heater (1), an evaporator (2), a U-tube (3), a short pipe I (4), a separation tower (5), and a bubble cap shut-off valve (6). The bottom of the evaporator (2) is connected to the bottom of the heater (1) through the U-tube (3), and the lower part of the evaporator (2) is connected to the upper part of the heater (1) through the short pipe I (4). A bubble cap shut-off valve (6) is connected between the evaporator (2) and the separation tower (5). The bubble cap shut-off valve (6) includes an outlet short pipe II (6.1), a bubble cap (6.2), a shut-off sleeve (6.3), a guide sleeve (6.4), a lifting rod (6.5), and a support (6.6). The outlet short pipe II (6.1) is connected to the top of the evaporator (2) and connected to the bubble cap (6.2) through a support pipe. The intercepting sleeve (6.3) is sleeved outside the outlet short pipe II (6.1). The intercepting sleeve (6.3) extends into the bubble cap (6.2), and there are gaps between the top surface of the bubble cap (6.2) and the inner wall of the bubble cap (6.2) and the intercepting sleeve (6.3). The intercepting sleeve (6.3) is connected to a lifting mechanism (7). The lifting mechanism (7) drives the intercepting sleeve (6.3) to move up and down to adjust the flow area between the intercepting sleeve (6.3) and the top surface of the bubble cap (6.2) so as to achieve precise control of the internal pressure of the esterification reactor.

2. The pressure control device for an esterification reactor specifically designed for a three-reactor process according to claim 1, characterized in that: The lifting mechanism (7) includes a transmission screw (7.1), a transmission nut (7.2), a bearing seat (7.3), a rocker arm (7.5), a connecting frame (7.6), and a connecting rod (7.4). The transmission screw (7.1) is connected to the drive shaft (8) via a transmission flange I (7.1.4). The drive shaft (8) is connected to a drive shaft assembly. The transmission screw (7.1) is a left- or right-hand trapezoidal screw, with a left-hand thread (7.1.1) at one end and a right-hand thread (7.1.2) at the other end. It passes through a fixing ring (7.1.3) in the middle. The fixing ring (7.1.3) is connected to a support (6.6). Both the left and right parts of the transmission screw (7.1) are threaded with a transmission nut. 7.2) Each of the transmission nuts (7.2) is fitted with a connecting rod (7.4) and the connecting rod (7.4) is perpendicular to the transmission screw (7.1). The two connecting rods (7.4) are hinged to the connecting frame (7.6) at the same end through a hinged rocker arm (7.5). The drive shaft (8) drives the transmission screw (7.1) to rotate. The rotation of the transmission screw (7.1) drives the rocker arm (7.5) to swing. The rocker arm (7.5) drives the lifting rod (6.5) to move up and down. The up and down movement of the lifting rod (6.5) drives the synchronous movement of the intercepting sleeve (6.3) to adjust the relative position between the intercepting sleeve (6.3) and the top surface of the bubble cap (6.2), thereby changing the flow area between them.

3. The pressure regulating device for the esterification reactor according to claim 2, characterized in that: The connecting frame (7.6) includes four extension rods forming a square structure. The ends of the four extension rods are connected to the lifting rod (6.5) by bolts. The lower end of the rocker arm (7.5) is sleeved on the head of the extension rod of the connecting frame (7.6) and is securely connected by a rolling bearing and a snap ring. When the rocker arm (7.5) swings, it can drive the connecting frame (7.6) to move up and down as a whole, thereby driving the lifting rod (6.5) to move vertically.

4. A pressure control device for an esterification reactor specifically designed for a three-reactor process, as described in claim 2 or 3, characterized in that: The drive shaft assembly includes a drive shaft (8.1) and a drive flange II (8.2). One end of the drive shaft (8.1) is connected to the drive shaft (8) through the drive flange II (8.2), and the other end of the drive shaft (8.1) passes through the separation tower (5) and is connected to an electric actuator (9) to drive the drive screw (7.1) to rotate.

5. The pressure control device for an esterification reactor specifically designed for a three-reactor process according to claim 4, characterized in that: The drive shaft (8.1) is provided with a sealing assembly (8.3) after passing through the separation tower (5) to prevent it from communicating with the outside after it passes through.

6. The pressure control device for an esterification reactor specifically designed for a three-reactor process according to claim 2, characterized in that: The flow-stopping sleeve (6.3) has at least two limiting grooves (6.3.1) at the bottom, multiple threaded holes (6.3.3) at the top, and multiple open grooves (6.3.2) at the bottom. The lifting rod (6.5) is connected to the threaded hole (6.3.3) of the flow-stopping sleeve (6.3) by bolts and is guided to move by the guide sleeve (6.4) at the top of the blister (6.2). The support tube has multiple sections that correspond one-to-one with the open grooves (6.3.2) to achieve quick positioning and installation of the flow-stopping sleeve (6.3). The limiting groove (6.3.1) has a fixedly installed slider, which controls the position range of the flow-stopping sleeve (6.3) moving up and down.

7. The pressure control device for an esterification reactor specifically designed for a three-reactor process according to claim 6, characterized in that: The lifting rod (6.5) is round in the middle, square at the top, and semi-cylindrical at the bottom. Both the square rod and the bottom have an axial through hole for bolt connection.

8. The pressure control device for an esterification reactor specifically designed for a three-reactor process according to claim 2, characterized in that: The rocker arm (7.5) is dumbbell-shaped, with rolling bearings at both ends and is positioned by snap rings.

9. The pressure control device for an esterification reactor specifically designed for a three-reactor process according to claim 3, characterized in that: The distance between the two middle long rods of the connecting frame (7.6) is 3 / 4 of the rod length, and the ends of the four extension rods are provided with axial threaded holes.

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