Esterification reaction device

Abstract

The utility model discloses an esterification reaction device which comprises a reaction kettle, the reaction kettle is provided with a feed port, and the reaction kettle is connected with a compressed air source through an air channel pipeline. The compressed air source sequentially passes through the constant flow valve, the rotor flow meter and the check valve and then enters the high pressure side of the differential pressure transmitter and the liquid level zero point of the reaction kettle, and the negative pressure side of the differential pressure transmitter is connected with the gas phase end of the top of the reaction kettle. A poking needle is arranged at an air outlet, located at the liquid level zero point of the reaction kettle, of the air channel pipeline, the poking needle is driven by a driving air cylinder to stretch out and draw back relative to the air outlet, and the driving air cylinder is electrically connected with the high-pressure side of the differential pressure transmitter. By using the combination of the differential pressure transmitter, the constant flow valve, the rotor flow meter and the check valve, the accuracy and the stability of liquid level measurement are ensured, and the problem that the measurement is inaccurate due to the fact that oligomer is adhered to a sling chain of a traditional electric buoy liquid level meter under the high-load condition is solved.

Description

Technical Field

[0001] The utility model relates to the field of chemical equipment, and particularly relates to an esterification reaction device. Background Art

[0002] Polyester is the basic raw material for producing industrial fiber filament products and packaging materials, and occupies an important position in chemical production. The esterification device is a key equipment in the polyester production process. In the esterification reaction device, the ethylene glycol (EG) and pure terephthalic acid (PTA) slurry configured in proportion carry out an esterification reaction under the action of a certain temperature and pressure to generate an oligomer with an esterification rate of 90% to 97%, and supply it to the subsequent polycondensation reaction device for polycondensation reaction.

[0003] When the temperature and pressure in the reaction device are kept stable, the esterification rate of the EG and PTA slurry is closely related to its reaction time. During the start-up stage, the liquid level of the reaction device directly represents the reaction residence time, and the process operator can qualitatively judge the esterification rate of the EG and PTA slurry based on this. Therefore, the liquid level of the esterification reaction device is one of the most basic and important controlled parameters in the esterification reaction process, and its accurate and stable measurement is related to the quality of the esterification reaction control.

[0004] Currently, an electric float level gauge is usually selected to measure the liquid level of the upper chamber (the part above the heat medium heater coil of the reaction device). Under normal process operations, the electric float level gauge can complete the liquid level measurement of the upper chamber of the esterification reaction device. However, when the production load is large, the gas-phase evaporation space of the reaction device becomes smaller, and improper process operations easily lead to the evaporation entrainment of oligomers. These oligomers adhere to the hanging chain of the electric float level gauge, which will cause inaccurate liquid level measurement, large fluctuations or even complete inability to measure. Summary of the Utility Model

[0005] The purpose of the utility model is to provide an esterification reaction device, which can improve the accuracy and stability of liquid level measurement, prevent the blockage of the gas pipeline, and ensure the continuity and reliability of the reaction process.

[0006] The technical solution adopted by the utility model to solve the above problems is: an esterification reaction device, including a reaction kettle, the reaction kettle is provided with a feeding port, the reaction kettle is connected with a compressed air source through a gas pipeline, the compressed air source enters the high-pressure side of a differential pressure transmitter and the liquid level zero point of the reaction kettle after passing through a constant flow valve, a rotameter and a check valve in sequence, and the negative pressure side of the differential pressure transmitter is connected with the gas-phase end at the top of the reaction kettle.

[0007] Preferably, a poking needle is provided at the air outlet of the gas pipeline at the zero liquid level of the reactor. The poking needle is driven by a driving cylinder to expand and contract relative to the air outlet, and the driving cylinder is electrically connected to the high-pressure side of the differential pressure transmitter.

[0008] Preferably, the reactor includes an outer thermal jacket and an inner reaction chamber. A stirrer is provided in the reaction chamber, and a coil heater is arranged around the outside of the lower half of the reaction chamber outside the stirrer.

[0009] Preferably, the stirrer includes a stirring shaft. The stirring shaft is provided with stirring paddles and is rotatably connected to a driving motor that drives its rotation. The driving motor is arranged at the top of the reactor.

[0010] Preferably, the reactor is connected to a material pump through a material pipeline to transport the material to a collector.

[0011] Preferably, a condenser is installed and adapted outside the material pipeline, and the condenser is arranged on the material pipeline between the reactor and the material pump.

[0012] Compared with the prior art, the present invention has the following advantages and effects:

[0013] By using the combination of a differential pressure transmitter, a constant flow valve, a rotameter, and a check valve, the present invention ensures the accuracy and stability of liquid level measurement, and avoids the problem that the traditional electric float liquid level gauge has inaccurate measurement due to oligomers adhering to its hanging chain under high load conditions. A poking needle is provided at the air outlet of the reactor at the zero liquid level. The poking needle is driven by a driving cylinder to expand and contract relative to the air outlet, and can effectively clean the blockage at the air outlet. When the value of the differential pressure transmitter exceeds the preset value, the driving cylinder is automatically started to drive the poking needle to perform a cleaning operation to ensure the smoothness of the gas pipeline. Description of the Drawings

[0014] Figure 1 is a schematic structural diagram of an esterification reaction device according to an embodiment of the present invention.

[0015] Figure 2 is a schematic structural diagram of a reactor according to an embodiment of the present invention.

[0016] Figure 3 is a partial enlarged view of the air outlet of the gas pipeline according to an embodiment of the present invention.

[0017] Reference Numerals of the Drawings: Reactor 11, Feeding Port 111, Gas Pipeline 12, Compressed Gas Source 13, Constant Flow Valve 14, Rotameter 15, Check Valve 16, Differential Pressure Transmitter 17, High Pressure Side 171, Negative Pressure Side 172, Pricker 21, Driving Cylinder 22, Thermal Jacket 31, Reaction Inner Chamber 32, Agitator 33, Agitation Shaft 331, Agitation Paddle 332, Driving Motor 333, Coil Heater 34, Material Pipeline 41, Material Pump 42, Collector 43, Condenser 44. Detailed Embodiments

[0018] The present utility model will be further described in detail below in conjunction with the drawings and through embodiments. The following embodiments are explanations of the present utility model, and the present utility model is not limited to the following embodiments.

[0019] Embodiment 1:

[0020] Refer to Figure 1 and Figure 2 , in this embodiment, an esterification reaction device is involved, which is specifically used for the esterification reaction process of ethylene glycol (EG) and pure terephthalic acid (PTA) slurry in industrial production. Specifically, it includes: a reactor 11, the reactor 11 is provided with a feeding port 111, the reactor 11 is connected to a compressed gas source 13 through a gas pipeline 12, and the compressed gas source 13 enters the high pressure side 171 of a differential pressure transmitter 17 and the liquid level zero point of the reactor 11 after passing through a constant flow valve 14, a rotameter 15, and a check valve 16 in sequence. The negative pressure side 172 of the differential pressure transmitter 17 is connected to the gas phase end at the top of the reactor 11.

[0021] Specifically, in this embodiment, the compressed gas source 13 drives the filtered and decompressed compressed air (generally using nitrogen as the gas source) to enter the high pressure side 171 of the differential pressure transmitter 17 and the equipment measurement point (liquid level zero point) after passing through the constant flow valve 14, the rotameter 15, and the check valve 16 in sequence, so that the air pressure is slightly higher than the pressure of the measured medium. When the pressure value of the differential pressure transmitter 17 rises and maintains at a constant value, the measured pressure at this time is equal to the static pressure generated by the liquid, that is: p = ρgH, where: p is the pressure measured by the differential pressure transmitter, ρ is the density of the measured medium, g is the local acceleration of gravity, and H is the height of the measured medium. Therefore, the liquid level of the medium is obtained by measuring the pressure. When using the blowing method liquid level gauge to measure the liquid level of the esterification reactor 11, because the working condition of the reactor 11 is slightly positive pressure, the negative pressure side 172 of the differential pressure transmitter 17 is connected to the top gas phase end of the reactor 11 to offset the pressure influence of the negative pressure side 172.

[0022] With the setting of the differential pressure transmitter 17, the present utility model ensures the accuracy and stability of liquid level measurement, and overcomes the problem of inaccurate measurement of traditional electric float level gauges under high load. In the present utility model, the constant flow valve 14 ensures that the compressed air source 13 enters the system at a stable flow rate, avoiding measurement errors caused by flow fluctuations. The rotameter 15 is used to monitor the gas flow rate in real time. According to the readings of the flowmeter, the operator can correct and adjust the constant flow valve 14 to achieve the best flow control effect.

[0023] The function of the check valve 16 is to prevent gas backflow, ensure that the gas only flows unidirectionally, and avoid interfering with the system. The design of the gas circuit system ensures the coordinated operation of the constant flow valve 14, the rotameter 15, and the check valve 16, making the pressure entering the differential pressure transmitter 17 constant, ensuring the continuity and reliability of the measurement, enabling the reaction kettle 11 to maintain stable liquid level measurement under different load conditions, and adapting to the load fluctuations during the production process. Through accurate liquid level measurement, the process operator can accurately judge the esterification rate of EG and PTA slurry, optimize the reaction time and conditions, and improve the quality of the oligomer. It reduces process fluctuations caused by inaccurate liquid level measurement and ensures product quality.

[0024] Through the improvement of the esterification reaction device in this embodiment, the problem of inaccurate liquid level measurement existing in the prior art is solved, and the stability and efficiency of the reaction process are ensured. The device is reasonably designed and can maintain accurate liquid level measurement under high-load production conditions, thereby effectively improving the control quality of the esterification reaction and being applicable to large-scale industrial production.

[0025] Due to the influence of small molecule oligomers, there is a problem of airway pipeline blockage, which is generally dredged by increasing the blowing pressure. Refer to Figure 3 , at the air outlet of the gas circuit pipeline 12 of this embodiment located at the liquid level zero point of the reaction kettle 11, there is a punch pin 21. The punch pin 21 is adapted to the inner diameter of the gas circuit pipeline 12, and it is driven by a driving cylinder 22 to stretch relative to the air outlet to loosen the blockage in the air outlet, and then the loosened blockage is blown out by compressed air, thereby effectively solving the blockage problem of the air outlet. The driving cylinder 22 is electrically connected to the high-pressure side 171 of the differential pressure transmitter 17. When the value of the differential pressure transmitter 17 exceeds the preset value (the pressure value generated when the medium is at the highest liquid level), the driving cylinder 22 automatically starts to drive the punch pin 21 to perform the cleaning operation, ensuring the smoothness and accuracy of the liquid level measurement system.

[0026] In this embodiment, the reactor 11 includes an outer thermal jacket 31 and an inner reaction chamber 32. The thermal jacket 31 provides a uniform heat distribution to maintain the stability of the esterification reaction temperature (265°C to 280°C). The reaction chamber 32 is provided with a stirrer 33, which enables the reactants to be fully mixed, thereby improving the reaction rate. The reaction chamber 32 is divided into upper and lower parts. A coil heater 34 is arranged around the outside of the stirrer 33 in the lower part, ensuring uniform heating and avoiding problems of local overheating or uneven temperature.

[0027] The stirrer 33 includes a stirring shaft 331, on which stirring paddles 332 are provided. The stirring shaft 331 is connected to a drive motor 333, and the drive motor 333 is arranged at the top of the reactor 11 and is used to drive the rotation of the stirring shaft 331. The design of the stirrer 33 enables the reactants to be fully mixed, thereby improving the reaction efficiency.

[0028] The reactor 11 is connected to a material pump 42 through a material pipeline 41 to convey materials to a collector 43. The collector 43 collects the oligomers generated by the esterification reaction for supply to a subsequent polycondensation reaction device for polycondensation reaction. A condenser 44 is adaptively installed outside the material pipeline 41. The condenser 44 is arranged on the material pipeline 41 between the reactor 11 and the material pump 42. The condenser 44 adopts a spiral structure, and the flow direction of the condensed water input into the condenser 44 is opposite to the material conveying direction in the material pipeline 41. The reverse flow enhances the condensation effect and improves the condensation efficiency.

[0029] What is described above in this specification is merely an example of the present utility model. Those skilled in the technical field to which the present utility model belongs can make various modifications or supplements to the described specific embodiments or use similar methods for substitution, as long as they do not deviate from the content of this specification of the present utility model or exceed the scope defined by this claims, they should all fall within the protection scope of the present utility model.

Claims

1. An esterification reaction device, comprising a reactor, wherein the reactor is provided with a feed port, characterized in that: The reactor is connected to a compressed air source through an air pipeline. The compressed air source enters the high-pressure side of the differential pressure transmitter and the liquid level zero point of the reactor through a constant flow valve, a rotor flowmeter and a check valve in sequence. The negative pressure side of the differential pressure transmitter is connected to the gas phase end at the top of the reactor.

2. An esterification reaction device according to claim 1, characterized in that: The gas outlet of the gas pipeline at the liquid level zero point of the reactor is provided with a poking needle, and the poking needle is driven to extend and retract relative to the gas outlet by a driving cylinder, and the driving cylinder is electrically connected to the high-voltage side of the differential pressure transmitter.

3. An esterification reaction device according to claim 2, characterized in that: The reactor comprises an outer heat jacket and an inner reaction chamber. The reaction chamber is provided with a stirrer. The lower part of the reaction chamber is provided with a coil heater around the outer side of the stirrer.

4. An esterification reaction device according to claim 3, characterized in that: The stirrer comprises a stirring shaft, which is provided with a stirring paddle and rotatably connected to a driving motor for driving the stirring paddle to rotate, and the driving motor is arranged on the top of the reaction kettle.

5. An esterification reaction device according to claim 4, characterized in that: The reactor is connected to a material pump via a material pipeline to transport the material to a collector.

6. An esterification reaction device according to claim 5, characterized in that: A condenser is installed on the outside of the material pipeline, and the condenser is arranged on the material pipeline between the reaction kettle and the material pump.

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