External heating type double-chamber esterification reaction device

Abstract

The utility model discloses an external heating type double-chamber esterification reaction device, and belongs to the field of polyester production. Comprising a reaction kettle and a tubular heater, a second material inlet is formed in the bottom of the tubular heater, a second material outlet is formed in the upper portion of the tubular heater, the interior of the reaction kettle is divided into an inner chamber and an outer chamber through an annular partition plate, and the inner chamber is communicated with the outer chamber; a first material outlet is formed in the bottom of the lower elliptical head of the inner chamber of the reaction kettle, and the second material outlet is communicated with the first material inlet through a short pipe. The esterification reaction device provided by the utility model is simpler in structure, short in flow, uniform in flow distribution, better in mixing effect, high in esterification efficiency, low in comprehensive energy consumption and wide in application range.

Description

Technical Field

[0001] The utility model relates to the field of polyester production, in particular to an externally heated double-chamber esterification reaction device. Background Art

[0002] There are two existing polyester production methods. One is an internal circulation fully mixed esterification reactor. The esterification reactor is mainly composed of a cylindrical barrel, an internally extended stirrer installed on the top of the barrel, a heated coil / tube bundle and a guide tube. Under the stirring action of the internal stirrer, the material forms an up and down circulation of the material, the material is fully mixed, the heat transfer coefficient is enhanced and the rate of the esterification reaction is increased. There are problems such as a long required reaction time, large equipment volume, difficulty in manufacturing, transportation and hoisting, and high power consumption. The other is an "external heating" esterification reactor, which is a series connection of a heater and a reactor in structure. The heater and the reactor are connected by a pipeline. Under the action of the density difference, the material circulates internally between the heater and the reactor, and the water generated by the reaction enters the reactor together with ethylene glycol for removal. The "external heating" reactor is usually a self-circulating type, which forms a circulation by relying on the density difference of the material before and after entering the heater. The esterification temperature of the self-circulating reactor is about 285℃, and a very high EG / PTA slurry molar ratio (1.85-2.0) is used. The purpose is to further increase the density difference by evaporating a large amount of free EG. A large amount of free EG evaporates in the esterification reactor. This part of EG does not participate in the esterification reaction, resulting in a large amount of heat waste. There are many heat exchange tubes inside the heater, which can easily cause uneven flow distribution. The newly added EG / PTA slurry has poor dispersion effect, which can easily cause mist entrainment.

[0003] CN212524113U discloses an external circulation multi-stage esterification reactor, including a reactor device and a tubular heater, wherein the reactor device includes a primary reactor and a secondary reactor, and utilizes the plug flow of materials through the full mixing device between the two devices to achieve a greater degree of conversion of reaction raw materials into reaction products. However, the reaction process is too long, the flow rate is prone to uneven distribution, and it is difficult to drain the materials when the machine is shut down, which easily leads to residual materials, affecting the product quality when the machine is started.

[0004] CN1248777C discloses a container device for reaction or separation using external circulation heating, including a container and an external heat exchanger, which solves the problem of insufficient flow caused by the power generated by thermosiphon alone being too small, and increases the circulation flow of materials. However, its esterification rate is low, only 92%, which increases the burden on subsequent reactors.

[0005] CN101613467B discloses a hybrid polyester esterification reactor, including a heating reaction tank and an evaporation reaction tank, and also including a power mixing section, the outlet of the heating reaction tank is connected to the inlet of the evaporation reaction tank, the power mixing section is provided with a venturi tube and a power pump matched with the venturi tube, the inlet and outlet of the power mixing section are respectively connected to the outlet of the evaporation reaction tank and the inlet of the heating reaction tank, thereby forming a circulation channel for the material, and the venturi tube is provided with a suction port for introducing new slurry. The invention utilizes the venturi tube to mix the slurry while sucking the slurry, effectively improving the mixing effect, and at the same time combining the power pump and the heating power to effectively form the circulation of the slurry, so that the overall structure of the reactor is simpler, the operation is simpler, the material mixing is more uniform, and it is more conducive to the esterification reaction. However, because it is provided with a power mixing section, the energy consumption required for the reaction process is increased. In the production process, once the power pump fails seriously, the device will be shut down.

[0006] Therefore, finding an esterification reaction device with simple structure, uniform flow distribution, high esterification efficiency, low energy consumption and good mixing effect is a problem that needs to be solved at present. Utility Model Content

[0007] The utility model aims to provide an esterification reaction device with simpler structure, shorter process, uniform flow distribution, better mixing effect, high esterification efficiency, low comprehensive energy consumption and wide application range.

[0008] The above technical problems are solved by the following technical solutions: including a reactor, a tubular heater, a short tube, a U-shaped pipe, a generated material outlet and an injection nozzle. The reactor is connected to the upper part of the tubular heater through a short tube, and the bottom of the reactor is connected to the bottom of the tubular heater through a U-shaped pipe. The material is internally circulated among the tubular heater, the reactor, the short tube and the U-shaped pipe.

[0009] Preferably, the reactor consists of an upper elliptical head, a lower elliptical head and a cylindrical body, the lower elliptical head is welded to the bottom end of the cylindrical body, and the upper elliptical head is welded to the top end of the cylindrical body.

[0010] Preferably, the upper elliptical end cap is provided with a gas phase outlet for discharging by-product water vapor and part of the unreacted EG vapor that undergoes flash separation.

[0011] Preferably, the lower elliptical head is provided with a first material outlet, and the cylindrical body is provided with a first material inlet near the lower elliptical head.

[0012] Preferably, the interior of the cylindrical body is divided into an inner chamber and an outer chamber by an annular partition. The outer chamber is a jacket structure. The inner chamber and the outer chamber are connected. The first material inlet is connected to the inner chamber, and the first material outlet is connected to the outer chamber.

[0013] Preferably, the annular partition is concentric with the cylindrical body.

[0014] Preferably, a small number of openings are provided on the annular partition, and the installation height of the annular partition does not exceed 1 / 2 of the height of the cylindrical body.

[0015] Preferably, the bottom of the annular partition is welded to the lower elliptical head, and a material discharge port is provided at the welding point between the bottom of the annular partition and the lower elliptical head.

[0016] Preferably, the top of the annular partition is provided with equidistantly arranged baffles, which are welded to the cylindrical body and the annular partition. The baffles play a role in circumferentially distributing the material flow, which can avoid short circuits of the material and dead corners of the material flow; the material flowing through the baffles enters the inner chamber at a certain angle to the horizontal plane, which not only enhances the effect of material mixing and dispersion, but also helps to reduce the entrainment of EG steam mist.

[0017] As a preferred method, the material flows in from the inner chamber and then flows out downward through the outer chamber, which can form an axial mixed flow, which is more conducive to the heat and mass transfer of the material, shortens the material circulation process, and avoids the phenomenon that the material cannot be completely discharged during shutdown.

[0018] Preferably, a regulating valve arranged on the gas phase outlet can control the pressure of the inner chamber. Under the rated production load, the pressure of the inner chamber is 0.02 MPa higher than that of the outer chamber.

[0019] As a preferred embodiment, the U-shaped pipe is a jacket structure. The jacket refers to a jacket added outside the pipe wall, and a heating medium can be passed into the jacket to heat the material in the pipe.

[0020] Preferably, the tubular heater is installed vertically, and the heating medium is gas-phase-induced. The material flows in the pipeline, and the heating medium flows in the shell of the tubular heater.

[0021] Preferably, the bottom cover of the tubular heater is provided with a second material inlet, and the second material inlet of the tubular heater is provided with an anti-vortex baffle and a perforated plate liquid distributor.

[0022] A perforated plate liquid distributor is arranged at the bottom of the tubular heater to evenly distribute the material entering the tubular heater, thereby avoiding overheating of part of the circulating material inside the tubular heater and causing a decrease in product quality, thereby improving product quality.

[0023] Preferably, the second material inlet of the tubular heater is connected to the U-shaped pipe. The esterified EG is directly injected into the U-shaped pipe without cooling, which can reduce energy consumption.

[0024] Preferably, a second material outlet is provided at the top of the tubular heater, and the second material outlet of the tubular heater is connected to the outer chamber through a short tube.

[0025] As a preferred embodiment, the U-shaped pipe is a jacket structure. The jacket refers to a jacket added outside the pipe wall, and a heating medium can be passed into the jacket to heat the material in the pipe.

[0026] Preferably, an esterification product outlet is provided at the bottom of the U-shaped pipe.

[0027] Preferably, four evenly distributed injection nozzles are provided on the upper portion of the vertical U-shaped pipe below the tubular heater.

[0028] Preferably, the axes of the four injection nozzles are on the same horizontal plane, and the axes of the four injection nozzles form a regular quadrilateral.

[0029] The four injection nozzles can inject the same material (EG / PTA slurry), different materials (EG / PTA slurry, esterified EG, catalyst and other additives), or a mixture of multiple materials (EG / PTA slurry + esterified EG + catalyst). Multi-point injection of EG / PTA slurry is conducive to the mixing and dispersion of the injected material and the circulating material.

[0030] The catalyst is injected from the bottom of the tubular heater, which speeds up the reaction of PTA and EG, reduces the heating temperature of the circulating material (the heating temperature is 260-270°C), and reduces heat consumption.

[0031] The beneficial effects of the utility model are:

[0032] The structural design of injecting the catalyst into the reactor at the bottom of the tubular heater accelerates the reaction rate of PTA and EG, reduces the heating temperature of the circulating material (heating temperature is 260-270℃), and reduces heat consumption. The esterification reactor is designed with a double-chamber and double-pressure structure to improve the equilibrium esterification rate. The design of the baffle plate welded on the top of the inner chamber of the esterification reactor not only strengthens the mixing and dispersion effect of the materials, but also makes the distribution of the material flow more uniform, avoiding the dead corner of the material flow; the material flowing through the baffle plate enters the outer chamber of the esterification reactor at a certain angle, which is conducive to reducing the entrainment of EG steam. The structural design of the annular baffle plate with holes inside the esterification reactor allows the material to flow into the inner chamber of the esterification reactor and then flow out downward from the outer chamber of the esterification reactor to form an axial mixed flow, and the circulating material flow is short, avoiding the image of the material not being able to be discharged completely during shutdown. The structural design of the high-temperature esterified EG (>160℃) directly injected at the bottom of the tubular heater reduces the density of the circulating flow inside the tubular heater, improves the circulation power of the circulating material, and reduces the heat consumption of the tubular heater. A perforated plate liquid distributor is arranged at the bottom of the tubular heater to evenly distribute the material entering the tubular heater, thereby avoiding overheating of part of the circulating material inside the tubular heater and causing a decrease in product quality, thereby improving product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic diagram of the structure of the external heating double chamber esterification reaction device

[0034] Figure 2 The main view of the reactor structure

[0035] Figure 3 Top view of the reactor structure

[0036] Figure 4 Schematic diagram of the baffle structure

[0037] Figure 5 Schematic diagram of the structure of the perforated plate liquid distributor

[0038] Figure 6 Front view of the injection nozzle installation orientation

[0039] Figure 7 Top view of the injection nozzle installation position

[0040] In the figure, 1. reactor, 1-1. upper elliptical head, 1-2. lower elliptical head, 1-3. cylindrical body, 1-4. annular partition, 1-5. inner chamber, 1-6. outer chamber, 1-7. gas phase outlet, 1-8. baffle, 1-9. first material outlet, 1-10. first material inlet, 2. tubular heater, 2-1. second material inlet, 2-2. second material outlet, 2-3. anti-vortex baffle, 2-4. perforated disc liquid distributor, 3. short tube, 4. U-shaped pipe, 5. generated material outlet, 6 injection nozzle. DETAILED DESCRIPTION

[0041] The present invention will be further described below in conjunction with the accompanying drawings and specific implementation methods.

[0042] like Figure 1 , Figure 2 As shown: an externally heated double-chamber esterification reaction device comprises: a reactor 1 and a tubular heater 2, one side of the reactor 1 is connected to the upper part of the tubular heater 2 through a short tube 3, and the bottom of the reactor 1 is connected to the bottom of the tubular heater 2 through a U-shaped pipe 4. The material is internally circulated between the reactor 1, the tubular heater 2, the short tube 3 and the U-shaped pipe 4.

[0043] The reactor 1 is a cylindrical structure consisting of an upper elliptical head 1-1, a cylindrical body 1-3 and a lower elliptical head 1-2. The upper elliptical head 1-1 is welded to the top of the cylindrical body 1-3, and the lower elliptical head 1-2 is welded to the bottom of the cylindrical body 1-3. The cylindrical body 1-3 is provided with a first material inlet 1-10 near the position where the lower elliptical head 1-2 is welded, and the first material inlet 1-10 is connected to one end of the short tube 3. The cylindrical body 1-3 is divided into two parts by an annular partition 1-4, namely an inner chamber 1-5 and an outer chamber 1-6. The annular partition 1-4 is concentric with the cylindrical body 1-3, and a small number of openings are provided on the annular partition 1-4. The installation position of the annular partition 1-4 does not exceed 1 / 2 of the height of the cylindrical body 1-3. The top of the annular partition 1-4 is welded with evenly distributed baffles 1-8. The evenly distributed baffles 1-8 play a role in circumferential distribution of material flow, avoiding short circuits of materials and dead corners of material flow; the material flowing through the baffles 1-8 enters the outer chamber 1-6 at a certain angle to the horizontal plane, which not only enhances the effect of material mixing and dispersion, but also helps to reduce the entrainment of ethylene glycol vapor. The inner chamber 1-5 is an annular cylindrical structure formed by the annular partition 1-4 welded on the lower elliptical head 1-2, and the baffles 1-8 welded on the top, and the cylindrical body 1-3. The inner chamber 1-5 is provided with a first material inlet 1-10 near the position where the lower elliptical head 1-2 is welded. The first material inlet 1-10 is connected to the other end of the short tube 3. The baffle 1-8 welded on the top of the annular partition 1-4 of the inner chamber 1-5 is used to evenly distribute the vaporized material heated by the tubular heater 2 to enhance the homogeneous distribution of the material flow. The part of the cylindrical body 1-3 divided by the annular partition 1-4 outside the inner chamber 1-5 is the outer chamber 1-6. The bottom of the outer chamber 1-6 is provided with a first material outlet 1-9. The first material outlet 1-9 is connected to the U-shaped pipe 4, and one end of the connection is the top of the vertical pipe connecting the reactor 1 and the U-shaped pipe 4. The upper elliptical end cap 1-1 is provided with a gas phase outlet 1-7, which is used to discharge the vaporized esterification reaction byproduct water and part of the unreacted ethylene glycol EG that have been flash-distilled and separated in the outer chamber 1-6, and the gas phase outlet 1-7 discharges the mixed steam into the subsequent separation tower for separation. The gas phase outlet 1-7 is provided with a regulating valve for adjusting the gas pressure of the outer chamber 1-6.

[0044] The bottom of the U-shaped pipe 4 is provided with a generated material outlet 5, and the generated material outlet 5 is used to discharge the esterification product after the reaction in the reactor 1 is completed. The U-shaped pipe 4 is a jacket structure, and the material is transmitted through the U-shaped pipe. The heat-conducting medium is added to the jacket to heat the material in the U-shaped pipe 4. The upper part of the vertical pipe of the U-shaped pipe 4 located below the tubular heater 2 is provided with the injection nozzle 6. There are 4 injection nozzles 6, which are evenly distributed on the outside of the U-shaped pipe. The axes of the injection nozzles 6 are on the same horizontal plane, and the axes of the 4 injection nozzles 6 form a regular quadrilateral.

[0045] The bottom end cap of the tubular heater 2 is provided with a second material inlet 2-1, and the second material inlet 2-1 is connected to the U-shaped pipe 4. The second material inlet 2-1 is provided with an anti-vortex baffle 2-3 and a perforated liquid distributor 2-4. One end of the anti-vortex baffle 2-3 is connected to the second material inlet 2-1, and the other end is connected to the perforated liquid distributor 2-4. The perforated liquid distributor 2-4 is horizontally placed on the anti-vortex baffle 2-3. The perforated liquid distributor 2-4 arranged at the bottom of the tubular heater 2 makes the material entering the tubular heater 2 from the second material inlet 2-1 evenly distributed, avoids overheating of part of the circulating material inside the tubular heater 2, and causes the product quality to deteriorate, and improves the product quality. The top of the tubular heater 2 is provided with a second material outlet 2-2, and the second material outlet 2-2 is connected to the other end of the short tube 3. The second material outlet arranged at the top of the tubular heater 2 is connected to the first material inlet 1-10 of the inner chamber 1-5 through the short tube 3. The first material outlet at the bottom of the outer chamber 1-6 is connected to the second material inlet 2-1 set at the bottom head of the tubular heater 2 through the U-shaped pipe 4, and the material circulates internally between the reactor 1, the tubular heater 2, the short tube 3 and the U-shaped pipe 4.

[0046] The specific embodiments of the present utility model will be described in detail below.

[0047] Example 1

[0048] The esterified EG and recycled EG from the reactor 1 are mixed with terephthalic acid PTA to form a slurry with a molar ratio of 1.6:1, and a certain proportion of catalyst is added to the EG / PTA slurry. According to the production requirements, the EG / PTA slurry mixed with a certain proportion of catalyst is injected into the U-shaped pipe 4 from the four injection nozzles 6 at a certain flow rate. A large amount of free EG in the EG / PTA slurry is heated and vaporized in the tubular heater 2, and the density of the EG / PTA slurry is reduced, providing power for the EG / PTA slurry to flow through the tubular heater 2. The temperature of the second outlet 2-2 of the material of the tubular heater 2 is controlled to be 260°C, and the tubular heater 2 is heated by gas phase conduction.

[0049] The esterification product, byproduct water, PTA and free EG of the tubular heater 2 enter the inner chamber 1-5 of the reactor 1 through the connecting short tube 3. The temperature of the reactor is 260°C and the pressure of the inner chamber 1-5 of the reactor 1 is about 0.02MPa. The material flows through the baffle 1-8 and enters the outer chamber 1-6 of the reactor 1. The pressure of the outer chamber 1-6 of the reactor 1 is slightly positive. PTA and EG continue to undergo esterification reaction in the outer chamber 1-6 of the reactor 1. The byproduct water and part of the unreacted ethylene glycol EG are flash-evaporated and separated in the outer chamber 1-6 of the reactor 1 and discharged in the form of steam through the gas phase outlet 1-7 on the reactor 1. The mixed steam enters the subsequent separation tower for separation. The esterification product, incompletely reacted PTA and EG flow into the U-shaped pipe 4, mix with the EG / PTA slurry injected from the injection nozzle 6, and then enter the tubular heater 2. The esterification product flows out from the esterification product outlet 5 located at the bottom of the U-shaped pipe 4 and is pumped into the subsequent polycondensation reactor.

[0050] Example 2

[0051] The esterified EG and recycled EG from the reactor 1 are mixed with terephthalic acid PTA to form a slurry with a molar ratio of 1.6:1, and a certain proportion of catalyst is added to the EG / PTA slurry. According to the production requirements, the EG / PTA slurry mixed with a certain proportion of catalyst is injected into the U-shaped pipe 4 from the four injection nozzles 6 at a certain flow rate. A large amount of free EG in the EG / PTA slurry is heated and vaporized in the tubular heater 2, and the density of the EG / PTA slurry is reduced, providing power for the EG / PTA slurry to flow through the tubular heater 2. The temperature of the second outlet 2-2 of the material of the tubular heater 2 is controlled to be 265°C, and the tubular heater 2 is heated by gas phase conduction.

[0052] The esterification product, byproduct water, PTA and free EG of the tubular heater 2 enter the inner chamber 1-5 of the reactor 1 through the connecting short tube 3. The temperature of the reactor is 265°C, and the pressure of the inner chamber 1-5 of the reactor 1 is about 0.02MPa. The material flows through the baffle 1-8 and enters the outer chamber 1-6 of the reactor 1. The pressure of the outer chamber 1-6 of the reactor 1 is slightly positive. PTA and EG continue to undergo esterification reaction in the outer chamber 1-6 of the reactor 1. The byproduct water and part of the unreacted ethylene glycol EG are flash-evaporated and separated in the outer chamber 1-6 of the reactor 1, and discharged in the form of steam through the gas phase outlet 1-7 on the reactor 1. The mixed steam enters the subsequent separation tower for separation. The esterification product, incompletely reacted PTA and EG flow into the U-shaped pipe 4, mix with the EG / PTA slurry injected from the injection nozzle 6, and then enter the tubular heater 2. The esterification product flows out from the esterification product outlet 5 located at the bottom of the U-shaped pipe 4 and is pumped into the subsequent polycondensation reactor.

[0053] Example 3

[0054] The esterified EG and recycled EG from the reactor 1 are mixed with terephthalic acid PTA to form a slurry with a molar ratio of 1.6:1, and a certain proportion of catalyst is added to the EG / PTA slurry. According to the production requirements, the EG / PTA slurry mixed with a certain proportion of catalyst is injected into the U-shaped pipe 4 from the four injection nozzles 6 at a certain flow rate. A large amount of free EG in the EG / PTA slurry is heated and vaporized in the tubular heater 2, and the density of the EG / PTA slurry is reduced, providing power for the EG / PTA slurry to flow through the tubular heater 2. The temperature of the second outlet 2-2 of the material of the tubular heater 2 is controlled to be 270°C, and the tubular heater 2 is heated by gas phase conduction.

[0055] The esterification product, byproduct water, PTA and free EG of the tubular heater 2 enter the inner chamber 1-5 of the reactor 1 through the connecting short tube 3. The temperature of the reactor is 270°C and the pressure of the inner chamber 1-5 of the reactor 1 is about 0.02MPa. The material flows through the baffle 1-8 and enters the outer chamber 1-6 of the reactor 1. The pressure of the outer chamber 1-6 of the reactor 1 is slightly positive. PTA and EG continue to undergo esterification reaction in the outer chamber 1-6 of the reactor 1. The byproduct water and part of the unreacted ethylene glycol EG are flash-evaporated and separated in the outer chamber 1-6 of the reactor 1 and discharged in the form of steam through the gas phase outlet 1-7 on the reactor 1. The mixed steam enters the subsequent separation tower for separation. The esterification product, incompletely reacted PTA and EG flow into the U-shaped pipe 4, mix with the EG / PTA slurry injected from the injection nozzle 6, and then enter the tubular heater 2. The esterification product flows out from the esterification product outlet 5 located at the bottom of the U-shaped pipe 4 and is pumped into the subsequent polycondensation reactor.

[0056] Comparative example 1.

[0057] The esterified EG and recycled EG from the reactor 1 are mixed with terephthalic acid PTA to form a slurry with a molar ratio of 1.6:1, and a certain proportion of catalyst is added to the EG / PTA slurry. According to the production requirements, the EG / PTA slurry mixed with a certain proportion of catalyst is injected into the U-shaped pipe 4 from any one of the four injection nozzles 6 at a certain flow rate. A large amount of free EG in the EG / PTA slurry is heated and vaporized in the tubular heater 2, and the density of the EG / PTA slurry is reduced, providing power for the EG / PTA slurry to flow through the tubular heater 2. The temperature of the second outlet 2-2 of the material of the tubular heater 2 is controlled to be 260°C, and the tubular heater 2 is heated by gas phase conduction.

[0058] The esterification product, byproduct water, PTA and free EG of the tubular heater 2 enter the inner chamber 1-5 of the reactor 1 through the connecting short tube 3. The temperature of the reactor is 260°C and the pressure of the inner chamber 1-5 of the reactor 1 is about 0.02MPa. The material flows through the baffle 1-8 and enters the outer chamber 1-6 of the reactor 1. The pressure of the outer chamber 1-6 of the reactor 1 is slightly positive. PTA and EG continue to undergo esterification reaction in the outer chamber 1-6 of the reactor 1. The byproduct water and part of the unreacted ethylene glycol EG are flash-evaporated and separated in the outer chamber 1-6 of the reactor 1 and discharged in the form of steam through the gas phase outlet 1-7 on the reactor 1. The mixed steam enters the subsequent separation tower for separation. The esterification product, incompletely reacted PTA and EG flow into the U-shaped pipe 4, mix with the EG / PTA slurry injected from the injection nozzle 6, and then enter the tubular heater 2. The esterification product flows out from the esterification product outlet 5 located at the bottom of the U-shaped pipe 4 and is pumped into the subsequent polycondensation reactor.

[0059] Comparison of Example 1 and Comparative Example 1 shows that multi-point injection of EG / PTA slurry is beneficial to the mixing and dispersion of the injected material and the circulating material.

[0060] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present utility model.

Claims

1. An externally heated double-chamber esterification reaction device, characterized in that: include: A reaction kettle (1) and a tubular heater (2), wherein one side of the reaction kettle (1) is connected to the upper part of the tubular heater (2) via a short tube (3), and the bottom of the reaction kettle (1) is connected to the bottom of the tubular heater (2) via a U-shaped pipe (4), and the U-shaped pipe (4) is provided with a generated material outlet (5) and an injection nozzle (6), and the generated material outlet (5) is arranged at the bottom of the U-shaped pipe (4).

2. The externally heated dual-chamber esterification reaction device according to claim 1, characterized in that: The reactor (1) is composed of an upper elliptical head (1-1), a lower elliptical head (1-2) and a cylindrical body (1-3); the interior of the reactor (1) is divided into an inner chamber (1-5) and an outer chamber (1-6) by an annular partition (1-4); the upper elliptical head (1-1) is provided with a gas phase outlet (1-7); the cylindrical body (1-3) is provided with a first material inlet (1-10); and the bottom of the lower elliptical head (1-2) is provided with a first material outlet (1-9).

3. The externally heated double-chamber esterification reaction device according to claim 2, characterized in that: The top of the annular partition (1-4) is provided with baffles (1-8) arranged in a uniform distribution, the baffles (1-8) are welded to the cylindrical body (1-3) and the annular partition (1-4), the annular partition (1-4) is provided with an opening, and the installation height of the annular partition (1-4) does not exceed 1 / 2 of the height of the cylindrical body (1-3).

4. The externally heated dual-chamber esterification reaction device according to claim 2, characterized in that: A second material inlet (2-1) is provided at the bottom of the tubular heater (2), an anti-vortex baffle (2-3) and a perforated plate liquid distributor (2-4) are provided above the second material inlet (2-1), and a second material outlet (2-2) is provided at the top of the tubular heater (2).

5. The externally heated dual-chamber esterification reaction device according to claim 4, characterized in that: The second material outlet (2-2) is connected to the first material inlet (1-10) through the short pipe (3), and the second material inlet (2-1) is connected to the first material outlet (1-9) through the U-shaped pipe (4).

6. The externally heated dual-chamber esterification reaction device according to claim 1, characterized in that: There are four injection nozzles (6), which are evenly distributed on the upper part of the vertical pipe connecting the U-shaped pipe (4) and the tubular heater (2).

7. The externally heated dual-chamber esterification reaction device according to claim 6, characterized in that: The axes of the four injection nozzles (6) are on the same horizontal plane, and the axes form a regular quadrilateral.

8. An externally heated dual-chamber esterification reaction device according to claim 1 or 2 or 3 or 4 or 6 or 7, characterized in that: The tubular heater (2) is installed vertically.

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