Semi-continuous polyester chip production device

Abstract

The utility model discloses a semi-continuous polyester chip production device which comprises an esterification kettle I, an esterification kettle II, a final polycondensation kettle, a pelletizing system and a stock bin which are connected in sequence, and further comprises a protection device which comprises a rectifying still, a storage tank and a conveying device which are connected in sequence, the rectifying kettle is communicated with the discharge holes of the esterification kettle I, the esterification kettle II and the final polycondensation kettle; and the liquid in the storage tank is respectively conveyed into the esterification kettle I, the esterification kettle II and the final polycondensation kettle by the conveying device. Through the arrangement of the protection device, ethylene glycol in the storage tank can be conveniently conveyed into the corresponding high-temperature reaction kettle through the conveying device, materials remaining on the stirring paddle, the kettle wall, the kettle bottom and other parts can be conveniently separated, and the local temperature in the kettle is reduced, so that the possibility of carbonization of the residual materials in the kettle is reduced, and the production efficiency is improved. According to the utility model, the residual materials in the kettles are protected, so that the residual materials in the kettles are protected, the carbonization of the residual materials is reduced, and the product quality is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of polyester production equipment, in particular to a semi-continuous polyester chip production device. Background Art

[0002] In the chemical production process, tubular reactors are a common reaction equipment, and the choice of their operating mode is of great significance to production efficiency, product quality, and cost control. Continuous operation and semi-continuous operation are two commonly used operating modes for tubular reactors, each with unique characteristics and applicable scenarios. The semi-continuous operation mode means that the raw materials enter the reactor in batches, and the products are discharged after each batch. The semi-continuous polyester chip production device generally adopts a three-kettle process, namely esterification kettle I, esterification kettle II (or pre-condensation kettle), and final polycondensation kettle. It is mainly used for the production of small batches of polyester products. It has the advantages of short production process, easy to control product quality, simple equipment maintenance and repair, strong production adaptability, and low loss when switching between varieties.

[0003] In the actual production process, due to the time logic relationship between the materials in each reactor, as well as the matching problem of polyester reaction and polycondensation reaction time, it is often difficult to ensure that there is material in each reactor, resulting in the esterification reactor II and the final polycondensation reactor being in a high-temperature waiting state. In particular, the esterification reactor II often has a longer high-temperature waiting time. The temperature of the esterification reactor II is generally above 250℃, and the temperature of the final polycondensation reactor is generally above 285℃. In the actual production process, there will be varying degrees of material residue in the reactor, such as on the reactor wall, stirring paddle, etc. The slurry in the final polycondensation reactor has a higher viscosity and more residue. The long-term retention of the material in the high-temperature reactor may cause the material to carbonize at high temperature, forming carbonized material. The carbonized material is easy to cause the filter element to be blocked during polyester synthesis, and at the same time, seriously affecting the product quality. Utility Model Content

[0004] The utility model provides a semi-continuous polyester chip production device to solve the above problems.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a semi-continuous polyester chip production device, which includes an esterification kettle I, an esterification kettle II, a final polycondensation kettle, a pelletizing system and a silo connected in sequence. The device also includes a protective device, which includes a distillation kettle, a storage tank and a conveying device connected in sequence. The distillation kettle is connected to the discharge port of the esterification kettle I, the esterification kettle II and the final polycondensation kettle, and the conveying device transports the liquid in the storage tank to the esterification kettle I, the esterification kettle II and the final polycondensation kettle respectively.

[0006] Preferably, a cooling tower is installed between the distillation kettle and the storage tank, the feed inlet of the cooling tower is connected to the discharge port of the distillation kettle, and the discharge port of the cooling tower is connected to the feed inlet of the storage tank.

[0007] Preferably, the esterification II kettle and the final polycondensation kettle are connected via a pre-condensation filter, and a delivery pump and a final polycondensation filter are sequentially connected between the final polycondensation kettle and the pelletizing system.

[0008] Preferably, the conveying device includes a flow meter, the feed port of the flow meter is connected to the storage tank, the discharge port of the flow meter is connected to a conveying pipe, a first three-way valve is installed on the conveying pipe, one end of the first three-way valve is connected to the final polycondensation kettle, the other end of the first three-way valve is connected to a liquid infusion pipe, a second three-way valve is installed at the end of the liquid infusion pipe, both ends of the second three-way valve are connected to branch pipes, and the two branch pipes are respectively connected to the esterification kettle I and the esterification kettle II.

[0009] Preferably, a third three-way valve is installed on the discharge pipe at the bottom of the esterification I kettle, one end of the third three-way valve is connected to the esterification II kettle, the other end of the third three-way valve is connected to the circulation pipe, the circulation pipe is connected to the feed port of the distillation kettle, the discharge port at the bottom of the esterification II kettle is connected to a fourth three-way valve, one end of the fourth three-way valve is connected to the final condensation filter, and the other end of the fourth three-way valve is connected to the circulation pipe; the discharge port at the bottom of the final polycondensation kettle is connected to a fifth three-way valve, one end of the fifth three-way valve is connected to the delivery pump, and the other end of the fifth three-way valve is connected to the circulation pipe.

[0010] Preferably, a sixth three-way valve is also provided on the circulation pipe, both ends of the sixth three-way valve are connected to the circulation pipe, and the other end of the sixth three-way valve is connected to the fourth three-way valve through a connecting pipe. A seventh three-way valve is provided on the circulation pipe, both ends of the seventh three-way valve are connected to the circulation pipe, and the other end of the seventh three-way valve is connected to the fifth three-way valve through a connecting pipe.

[0011] Preferably, a waste liquid outlet is provided at the bottom of the distillation kettle, and the conveying device adopts gravity or nitrogen micro-positive pressure conveying mode.

[0012] Preferably, the device further comprises a slurry preparation kettle, the discharge port of the slurry preparation kettle is connected to the feed port of the esterification kettle I, the exhaust ports on the top of the esterification kettle I and the esterification kettle II are both connected to an exhaust pipe, the exhaust pipe is connected to the process tower through a three-way valve, and the discharge port of the process tower is connected to a collection tank;

[0013] The top of the final polycondensation kettle is also connected to a condenser.

[0014] The beneficial effects of the present invention are as follows: (1) By setting up the protection device, it is convenient to transport the ethylene glycol in the storage tank to the corresponding high-temperature reactor through the conveying device, and it is convenient to separate the materials remaining in the stirring blade, the reactor wall, the reactor bottom and other parts, and reduce the local temperature in the reactor, thereby reducing the possibility of carbonization of the residual materials in the reactor, so as to achieve the function of protecting the residual materials in the reactor, realize the protection of the residual materials in each reactor, reduce the carbonization of the residual materials, and improve the quality of the product. (2) The added ethylene glycol is recycled in the protection device, reducing the material consumption and cost investment. (3) The carbonized materials in the esterification reactor I, the esterification reactor II and the final polycondensation reactor are reduced, which is convenient to reduce the frequency of changing the filter element in the pre-condensation filter and the final polycondensation filter, prolong the service life of the filter element, reduce the material waste caused by changing the filter element, and reduce the production cost. (4) By setting up multiple three-way valves, it is convenient to realize the protection of each reactor individually or simultaneously, and improve the working capacity and efficiency of the protection device. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the structure of a semi-continuous polyester chip production device in the prior art;

[0016] Figure 2 It is a structural diagram of the utility model;

[0017] Figure 3 This is a schematic diagram of the connection relationship between the protection device of the utility model and the esterification kettle, esterification kettle II, and final polycondensation kettle. DETAILED DESCRIPTION

[0018] The present invention will be further described below in conjunction with the accompanying drawings.

[0019] A semi-continuous polyester chip production device, such as Figure 1 、 Figure 2 and Figure 3 As shown, the device includes an esterification kettle I 1, an esterification kettle II 2, a final polycondensation kettle 3, a pelletizing system 4, and a silo 5, which are connected in sequence. The prepared slurry is placed in the esterification kettle I 1. Through the stirring and mixing of the esterification kettle I and the heating of the heat medium coil, the slurry undergoes an esterification reaction at a certain temperature. The material obtained after the reaction enters the esterification kettle II 2 through the discharge port at the bottom of the esterification kettle I 1. In the esterification kettle II 2, the material continues to undergo esterification reaction due to the action of the stirrer and the heat medium coil. The esterified product obtained after the reaction is discharged from the bottom of the esterification kettle II 2 under the action of the pressure difference and enters the final polycondensation kettle 3. The esterified product undergoes polycondensation reaction in the final polycondensation kettle 3. The product obtained by the polycondensation reaction is transported to the pelletizing system 4 for pelletizing, and the resulting granular polyester product is transported to the silo 5 for storage. The material can be transported between the various devices by gravity, pressure difference, or pump, which is a prior art and will not be described in detail here.

[0020] The apparatus also includes a protective device comprising a sequentially connected distillation kettle 6, a storage tank 7, and a conveying device. The distillation kettle 6 is connected to the discharge ports of the esterification kettle I 1, the esterification kettle II 2, and the final polycondensation kettle 3. The conveying device transports the liquid in the storage tank 7 to the esterification kettle I 1, the esterification kettle II 2, and the final polycondensation kettle 3, respectively. Ethylene glycol in the esterification kettles I 1, II 2, and 3 enters the distillation kettle 6, where it undergoes rectification and the purified ethylene glycol is transported to the storage tank 7. When a high-temperature waiting state is reached in each kettle, the ethylene glycol in the storage tank 7 is transported to the corresponding esterification kettle I 1, II 2, and final polycondensation kettle 3 via the conveying device, thereby increasing the volume of material in each kettle. By activating the stirring system in each kettle, material remaining on the stirring paddles, kettle walls, and bottom of the kettle is dislodged, and the local temperature within the kettle is lowered, thereby reducing the possibility of carbonization of residual material within the kettle, thereby protecting the residual material within the kettle. After the waiting time for the materials in each kettle has expired, the remaining materials in the kettle are reintroduced into the distillation kettle 6 along with the ethylene glycol. The distillation kettle 6 further distills the materials and transfers the purified ethylene glycol to the storage tank 7, thereby purifying the ethylene glycol and facilitating its subsequent use during the high-temperature waiting time. This method, on the one hand, protects the residual materials in each kettle, reduces carbonization of the residual materials, and improves product quality. On the other hand, the added ethylene glycol is recycled in the protection device, reducing material consumption and cost investment.

[0021] In another embodiment, a cooling tower 8 is further installed between the distillation kettle 6 and the storage tank 7. The feed port of the cooling tower 8 is connected to the discharge port of the distillation kettle 6, and the discharge port of the cooling tower 8 is connected to the feed port of the storage tank 7. The cooling tower 8 is cooled by circulating cooling water to quickly cool the distilled ethylene glycol, thereby achieving the effect of reducing the temperature in each kettle by ethylene glycol.

[0022] In another embodiment, the esterification II kettle 2 and the final polycondensation kettle 3 are connected via a pre-shrinkage filter 9, and the final polycondensation kettle 3 and the pelletizing system 4 are sequentially connected with a delivery pump 10 and a final polycondensation filter 11. The provision of the pre-shrinkage filter 9 facilitates filtering of the material obtained by esterification in the esterification II kettle 2 to improve product quality, while the provision of the final polycondensation filter 11 facilitates filtering of the polycondensate formed after polycondensation, further improving product quality. The provision of the protective device reduces the amount of carbonized material in the esterification I kettle 1, the esterification II kettle 2, and the final polycondensation kettle 3, facilitating a reduction in the frequency of filter element replacement in the pre-shrinkage filter 9 and the final polycondensation filter 11, thereby extending the service life of the filter element, reducing material waste caused by filter element replacement, and reducing production costs.

[0023] In another embodiment, the conveying device includes a flow meter 12, the feed port of the flow meter 12 is connected to the storage tank 7, the discharge port of the flow meter 12 is connected to the conveying pipe 13, the conveying pipe 13 is installed with a first three-way valve 14, one end of the first three-way valve 14 is connected to the final polycondensation reactor 3, the other end of the first three-way valve 14 is connected to a liquid infusion pipe 15, the end of the liquid infusion pipe 15 is installed with a second three-way valve 16, both ends of the second three-way valve 16 are connected to branch pipes 17, and the two branch pipes 17 are respectively connected to the esterification reactor I 1 and the esterification reactor II 2. The conveying device also includes a power source, that is, a power source for conveying ethylene glycol to each reactor through the storage tank 7. The power source can be a liquid pump (not shown in the figure), the liquid pump is located between the storage tank 7 and the flow meter 12, and the power source can also be a liquid that uses the gravity of the liquid to convey ethylene glycol to the corresponding reactor. There is no specific limitation on the power source here. When a high temperature waiting for the kettle appears in a certain kettle, the power source is started and the corresponding valve in the first three-way valve 14 is opened. If the high temperature waiting for the kettle appears in the final polycondensation kettle 3, the pipeline between the first three-way valve 14 and the final polycondensation kettle 3 is opened, so that the ethylene glycol in the storage tank 7 enters the final polycondensation kettle 3 after being measured by the flow meter 12, and the final polycondensation kettle 3 is cooled and the material is removed. If a high temperature waiting for the kettle appears in the esterification kettle I 1 or the esterification kettle II 2, the pipeline between the first three-way valve 14 and the infusion pipe 15 is opened, and then the second three-way valve 14 is opened. The three-way valve 16 and the corresponding branch pipe 17 allow the ethylene glycol in the storage tank 7 to be transported sequentially through the delivery pipe 13 and the branch pipe 17 to the esterification kettle 1 or the esterification kettle 2, thereby protecting the residual materials in the esterification kettle 1 or the esterification kettle 2. If the three reactors are all at high temperatures, the first three-way valve 14 and the second three-way valve 16 are opened simultaneously, allowing the ethylene glycol in the storage tank 7 to be transported to the three reactors simultaneously, thereby protecting the materials in the reactors. The configuration of the first three-way valve 14 and the second three-way valve 16 facilitates the independent or simultaneous protection of each reactor, improving the working capacity and efficiency of the protection device.

[0024] In another embodiment, a third three-way valve 18 is installed on the discharge pipe at the bottom of the esterification I kettle 1, one end of the third three-way valve 18 is connected to the esterification II kettle 2, and the other end of the third three-way valve 18 is connected to a circulation pipe 19, and the end of the circulation pipe 19 away from the esterification I kettle 1 is connected to the feed port of the distillation kettle 6, and the discharge port at the bottom of the esterification II kettle 2 is connected to a fourth three-way valve 20, one end of the fourth three-way valve 20 is connected to the final reduction filter 11, and the other end of the fourth three-way valve 20 is connected to the circulation pipe 19; a fifth three-way valve 21 is connected to the discharge port at the bottom of the final polycondensation kettle 3, one end of the fifth three-way valve 21 is connected to the delivery pump 10, and the other end of the fifth three-way valve 21 is connected to the circulation pipe 19. During the production process, the esterification kettle 1 transfers the material after the esterification reaction to the esterification kettle 2 via the fifth three-way valve 21. The material in the esterification kettle 2 continues to undergo esterification reaction and the esterification product is transferred to the pre-shrink filter 9 via the fourth three-way valve 20. The filtered material is transferred to the final shrink filter 11 for polycondensation reaction. The resulting polycondensation product is transferred to the final shrink filter 11 via the transfer pump 10 for filtration. It then enters the pelletizing system 4 for pelletizing and is transferred to the intermediate silo 5. During the production process, if a high temperature waiting state occurs in any of the esterification kettles 1, esterification kettle 2, or final polycondensation kettle 3, the ethylene glycol in the storage tank 7 is transferred to the corresponding kettle via the transfer device. After the high temperature waiting state ends, the three-way valve at the bottom of the corresponding kettle can be opened to facilitate the transfer of the material in the kettle to the distillation kettle 6 via the circulation pipe 19. By setting the third three-way valve 18, the fourth three-way valve 20 and the fifth three-way valve 21, it is convenient to transport the materials in each reactor to the distillation reactor 6 separately or simultaneously, realizing the possibility of the protection device to have a separate or simultaneous protection effect.

[0025] In another embodiment, a sixth three-way valve 22 is further provided on the circulation pipe 19, both ends of the sixth three-way valve 22 are connected to the circulation pipe 19, and the other end of the sixth three-way valve 22 is connected to the fourth three-way valve 20 through a connecting pipe. A seventh three-way valve 23 is provided on the circulation pipe 19, both ends of the seventh three-way valve 23 are connected to the circulation pipe 19, and the other end of the seventh three-way valve 23 is connected to the fifth three-way valve 21 through a connecting pipe.

[0026] In another embodiment, a waste liquid port is provided at the bottom of the distillation kettle 6, and the conveying device adopts gravity or nitrogen micro-positive pressure conveying mode. Through the setting of the waste liquid port, it is convenient to discharge the waste liquid in the distillation kettle 6 regularly.

[0027] In another embodiment, the apparatus further comprises a slurry preparation kettle 24, the discharge port of which is connected to the feed port of the esterification kettle I 1, the exhaust ports at the tops of the esterification kettle I 1 and the esterification kettle II 2 are both connected to exhaust pipes, which are connected to the process tower 25 via a three-way valve, and the discharge port of the process tower 25 is connected to a collection tank 26; the top of the final polycondensation kettle 3 is also connected to a condenser 27. During the reaction, the water and evaporated ethylene glycol produced by the esterification kettle I 1 and the esterification kettle II 2 are transported to the process tower 25 through the exhaust pipe via the pressure control device. The ethylene glycol, after being treated by spray cooling in the process tower 25, is recovered into the collection tank 26 for use in subsequent reactions, thereby reducing the waste of ethylene glycol and improving energy efficiency.

[0028] During use, the prepared slurry in the slurry preparation kettle 24 is transported to the esterification kettle I 1. Under the action of the stirring and mixing of the esterification kettle I and the heating of the heat medium coil, the slurry undergoes esterification reaction at a certain temperature. The material obtained after the reaction enters the esterification kettle II 2 through the discharge port at the bottom of the esterification kettle I 1. In the esterification kettle II 2, the material continues to undergo esterification reaction by relying on the action of the stirrer and the heat medium coil. The esterified product obtained after the reaction is discharged from the bottom of the esterification kettle II 2 under the action of the pressure difference and enters the pre-shrinkage filter 9. The filtered material enters the final polycondensation kettle 3, and the esterified product is discharged in the final polycondensation kettle 3. A polycondensation reaction is carried out in the polycondensation kettle 3, and the product obtained by the polycondensation reaction is conveyed to the final polycondensation filter 11 via the conveying pump 10. The filtered material is conveyed to the pelletizing system 4 for pelletizing operation, and the obtained granular polyester product is conveyed to the silo 5 for storage. The water and evaporated ethylene glycol produced by the esterification kettle I 1 and the esterification kettle II 2 are conveyed to the process tower 25 through the exhaust pipe via the pressure control device. The ethylene glycol after spray cooling and other treatments in the process tower 25 is recovered into the collection tank 26, and the vaporized ethylene glycol in the final polycondensation kettle 3 enters the condenser 27 for condensation. During the reaction process, if high-temperature waiting kettle appears in the esterification I kettle 1, the esterification II kettle 2 or the final polycondensation kettle 3, open the first three-way valve 14 or open the first three-way valve 14 and the second three-way valve 16 at the same time, and the ethylene glycol in the storage tank 7 is transported to the corresponding kettle. After the high-temperature waiting kettle ends, the three-way valve at the bottom of the corresponding kettle can be opened to facilitate the transportation of the material in the kettle to the distillation kettle 6 through the circulation pipe 19. The material entering the distillation kettle 6 is purified to obtain relatively pure ethylene glycol, and is cooled in the cooling tower and then transported to the storage tank 7 for recycling during subsequent high-temperature waiting kettle.

[0029] The above embodiments do not impose any formal restrictions on the shape, material, structure, etc. of the utility model. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the utility model fall within the scope of protection of the technical solution of the utility model.

Claims

1. A semi-continuous polyester chip production device, comprising an esterification reactor I, an esterification reactor II, a final polycondensation reactor, a pelletizing system, and a silo connected in sequence, characterized in that: The device also includes a protection device, which includes a distillation kettle, a storage tank and a conveying device connected in sequence. The distillation kettle is connected to the discharge ports of the esterification kettle I, the esterification kettle II and the final polycondensation kettle. The conveying device conveys the liquid in the storage tank to the esterification kettle I, the esterification kettle II and the final polycondensation kettle respectively.

2. The semi-continuous polyester chip production device according to claim 1, characterized in that: A cooling tower is also installed between the distillation kettle and the storage tank. The feed port of the cooling tower is connected to the discharge port of the distillation kettle, and the discharge port of the cooling tower is connected to the feed port of the storage tank.

3. The semi-continuous polyester chip production device according to claim 2, characterized in that: The esterification II kettle and the final polycondensation kettle are connected through a pre-condensation filter, and the final polycondensation kettle and the pelletizing system are also connected in sequence with a delivery pump and a final polycondensation filter.

4. The semi-continuous polyester chip production device according to claim 3, characterized in that: The conveying device includes a flow meter, the feed port of the flow meter is connected to the storage tank, the discharge port of the flow meter is connected to a conveying pipe, a first three-way valve is installed on the conveying pipe, one end of the first three-way valve is connected to the final polycondensation kettle, the other end of the first three-way valve is connected to a liquid infusion pipe, a second three-way valve is installed at the end of the liquid infusion pipe, both ends of the second three-way valve are connected to branch pipes, and the two branch pipes are respectively connected to the esterification kettle I and the esterification kettle II.

5. The semi-continuous polyester chip production device according to claim 4, characterized in that: A third three-way valve is installed on the discharge pipe at the bottom of the esterification kettle I, one end of the third three-way valve is connected to the esterification kettle II, the other end of the third three-way valve is connected to the circulation pipe, the circulation pipe is connected to the feed port of the distillation kettle, the discharge port at the bottom of the esterification kettle II is connected to the fourth three-way valve, one end of the fourth three-way valve is connected to the final condensation filter, and the other end of the fourth three-way valve is connected to the circulation pipe; the discharge port at the bottom of the final polycondensation kettle is connected to the fifth three-way valve, one end of the fifth three-way valve is connected to the delivery pump, and the other end of the fifth three-way valve is connected to the circulation pipe.

6. The semi-continuous polyester chip production device according to claim 1, characterized in that: A sixth three-way valve is also provided on the circulation pipe, both ends of which are connected to the circulation pipe, and the other end of the sixth three-way valve is connected to the fourth three-way valve through a connecting pipe. A seventh three-way valve is provided on the circulation pipe, both ends of which are connected to the circulation pipe, and the other end of the seventh three-way valve is connected to the fifth three-way valve through a connecting pipe.

7. The semi-continuous polyester chip production device according to claim 1, characterized in that: A waste liquid outlet is provided at the bottom of the distillation kettle, and the conveying device adopts a gravity or nitrogen micro-positive pressure conveying mode.

8. A semi-continuous polyester chip production device according to any one of claims 1 to 7, characterized in that: The device also includes a slurry preparation kettle, the discharge port of the slurry preparation kettle is connected to the feed port of the esterification kettle I, the exhaust ports on the top of the esterification kettle I and the esterification kettle II are both connected to exhaust pipes, the exhaust pipes are connected to the process tower through a three-way valve, and the discharge port of the process tower is connected to a collection tank; The top of the final polycondensation kettle is also connected to a condenser.

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