Melt cooling device of direct spinning melt conveying system

Abstract

The utility model relates to the technical field of chemical fiber production, in particular to a melt cooling device of a direct spinning melt conveying system, a melt cooler is arranged on a conveying pipeline in the direct spinning melt conveying system, the melt cooling device further comprises an ethylene glycol evaporator of a polyester device, and a heating medium pipeline and a refrigerant pipeline are arranged on the ethylene glycol evaporator. The refrigerant pipeline and the heating medium pipeline are connected to the melt coolers, a heating medium pump is arranged on the heating medium pipeline, the heating medium pipeline is connected to the refrigerant pipeline corresponding to each melt cooler through an adjusting pipeline, and an adjusting valve group is arranged at the joint of the adjusting pipeline and the refrigerant pipeline and used for adjusting the temperature of a refrigerant medium. The cooling medium generated by the ethylene glycol evaporator of the polyester device is used for cooling the melt in the melt cooler, and the heating medium generated by the melt cooler is used for heating the ethylene glycol evaporator, so that the full utilization of energy is realized, the energy consumption waste is reduced, and the equipment cost and the production cost are reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of chemical fiber production, in particular to a melt cooling device for a direct spinning melt conveying system. Background Art

[0002] At present, China's chemical fiber industry is still large but not strong. With the rapid large-scale development of the polyester and polyester fiber industry, especially for some mainstream polyester technologies, the production capacity of conventional polyester is large, the process flow is fixed, the production specifications are single, and the device design is seriously homogenized. The production mode of high input, high consumption, and high energy consumption has not been fundamentally changed, and it is obvious that it cannot meet the development needs of the new quality productivity of high-quality and low-energy consumption production process technologies in today's society.

[0003] The melt coming out of the final polymerization kettle of the polyester device passes through a discharge pump, a melt filter, and a melt cooler, and is transported through a melt jacketed pipe with heat medium insulation and distributed to each spinning box by a distribution valve. In order to meet the melt pressure required for spinning, a booster pump is provided in the melt pipeline; in order to overcome the temperature rise generated after the melt passes through the booster pump and ensure the quality of the melt, a melt cooler is provided after the booster pump. Before entering the spinning box, the melt first passes through a static mixer to ensure that the temperature and viscosity of the polyester melt are the same when entering the spinning process. At present, the process technical scheme of the heat medium system of the melt cooler designed in the domestic mainstream polyester device is that each cooler uses two heat medium circulation pumps and a group of finned tubes for independent circulation temperature control to realize the polyester melt cooling process to meet the production's function of regulating the temperature of the spin-friendly melt. Generally, a domestic mainstream traditional design of a polyester device with an annual production capacity of 400,000 tons can be equipped with 14 spinning production lines, with 48 spinning positions in a single-line layout. A total of six booster pumps are set in the melt conveying system pipeline, and six melt coolers are provided. According to this process route design, at least twelve heat medium circulation pumps, six groups of finned tubes, and six groups of regulating valve groups need to be configured to realize the melt cooling function, which greatly increases the equipment input cost and production operation cost, and the cooling method is finned tube cooling, resulting in great energy loss.

[0004] Therefore, it is of great practical significance to study a heat medium system for a melt cooler. Content of the Utility Model

[0005] The utility model provides a melt cooling device for a direct spinning melt conveying system to solve the above technical deficiencies, which can reduce energy consumption, equipment cost, and usage cost.

[0006] The utility model discloses a melt cooling device for a direct spinning melt conveying system. A melt cooler is provided on a conveying pipeline in the direct spinning melt conveying system. The device also includes an ethylene glycol evaporator of a polyester device. A heat medium pipeline and a refrigerant pipeline are arranged on the ethylene glycol evaporator. The refrigerant pipeline and the heat medium pipeline are connected to the melt cooler. A heat medium pump is arranged on the heat medium pipeline. The heat medium pipeline is connected to the corresponding refrigerant pipeline of each melt cooler through an adjusting pipeline. A regulating valve group is arranged at the connection of the adjusting pipeline and the refrigerant pipeline for regulating the temperature of the refrigerant medium. The ethylene glycol evaporator is also connected to a heat medium station, and the heat medium station supplies high-temperature heat medium to the ethylene glycol evaporator.

[0007] In a single set of direct spinning melt conveying system, three melt coolers are configured. The heat medium pipeline and the refrigerant pipeline of one ethylene glycol evaporator of the polyester device are respectively connected to six melt coolers in two sets of direct spinning melt conveying systems.

[0008] The structure of the regulating valve group is as follows: on the refrigerant pipeline upstream of the connection of the refrigerant pipeline and the adjusting pipeline, a stop valve, a pneumatic regulating valve, and a stop valve are sequentially arranged. Branches are arranged in parallel on the refrigerant pipelines outside the two stop valves, and stop valves are also arranged on the branches; on the adjusting pipeline upstream of the connection of the refrigerant pipeline and the adjusting pipeline, a stop valve, a pneumatic regulating valve, and a stop valve are sequentially arranged. Branches are arranged in parallel on the adjusting pipelines outside the two stop valves, and stop valves are also arranged on the branches.

[0009] A refrigerant low discharge pipe is arranged between one of the stop valves and the pneumatic regulating valve on the refrigerant pipeline and the adjusting pipeline, and a discharge valve is arranged on the refrigerant low discharge pipe.

[0010] Valves are arranged on the heat medium pipelines at both ends of the heat medium pump. A bypass is arranged in parallel on the heat medium pipelines outside the valves at both ends of the heat medium pump, and valves, a heat medium pump, and valves are also sequentially arranged on the bypass.

[0011] A method for cooling a melt by using the above melt cooling device. The refrigerant medium is conveyed from the refrigerant pipeline on the ethylene glycol evaporator in the ethylene glycol steam injection system in the polyester device to six melt coolers in two sets of direct spinning melt conveying systems. Heat exchange is carried out in the melt cooler to cool the melt. The refrigerant medium is heated to form a heat medium medium. The heat medium medium is conveyed to the ethylene glycol evaporator through the heat medium pipeline to heat the ethylene glycol. The heat medium medium is cooled to form a refrigerant medium, and the above process is repeated in a cycle; wherein the ratio of the refrigerant medium and the heat medium medium entering the refrigerant pipeline is adjusted through the regulating valve group to adjust the temperature of the refrigerant medium entering the melt cooler to meet the requirement of melt cooling.

[0012] On a single polyester plant, corresponding to two melt direct spinning conveying systems, a total of six melt coolers are integrated. The ethylene glycol evaporator on the polyester plant is used to connect with the six melt coolers to supply refrigerant medium for the melt coolers. This can reduce the equipment investment and production cost of six groups of finned tubes, one air cooler, one oil-water evaporator and multiple heat medium pumps in the traditional design, and can reduce the equipment cost.

[0013] During the circulation process of the whole heat medium and refrigerant medium, only two heat medium pumps need to be configured, which reduces the number of heat medium pumps and the equipment cost. Among them, the heat medium pump can adopt a variable frequency speed regulation heat medium pump, which can adjust the speed of the heat medium pump according to the demand to achieve flow control and meet the different process temperature control conditions of each melt cooler.

[0014] Temperature sensors are installed at both the inlet and outlet of the melt cooler to detect the melt temperature and monitor the heat exchange effect. Pressure sensors are installed at both the inlet and outlet of the melt cooler to detect the melt pressure to judge whether there are faults such as blockage in the melt cooler.

[0015] The ethylene glycol evaporator of the ethylene glycol steam injection system is used to generate ethylene glycol steam for the use of the injection pump group.

[0016] The melt cooling device of a direct spinning melt conveying system obtained by the present utility model uses the refrigerant medium generated by the ethylene glycol evaporator of the polyester plant to cool the melt in the melt cooler, and the heat medium generated by the melt cooler heats the ethylene glycol evaporator, realizing the full utilization of energy, reducing energy consumption waste, and reducing equipment cost and production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic structural diagram of the present utility model;

[0018] Figure 2 is Figure 1 a partially enlarged schematic view of part A of

[0019] Figure 3 is Figure 1 a partially enlarged schematic view of part B of DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] In order to further elaborate on the technical means and effects adopted by the present utility model to achieve the predetermined utility model purpose, the following will, in conjunction with the accompanying drawings and preferred embodiments, describe in detail the specific embodiments, structures, features and their effects according to the present utility model.

[0021] Embodiment 1:

[0022] As shown in Figure 1 、 Figure 2 、 Figure 3As shown in the figure, the utility model discloses a melt cooling device for a direct spinning melt conveying system. A melt cooler 2 is provided on the conveying pipeline in the direct spinning melt conveying system 1. It also includes an ethylene glycol evaporator 4 of a polyester device. A heat medium pipeline 6 and a refrigerant pipeline 6 are arranged on the ethylene glycol evaporator 4. The refrigerant pipeline 6 and the heat medium pipeline 6 are connected to the melt cooler 2. A heat medium pump 13 is arranged on the heat medium pipeline 6. The heat medium pipeline 6 is connected to the corresponding refrigerant pipeline 6 of each melt cooler 2 through an adjusting pipeline 7. A regulating valve group is arranged at the connection of the adjusting pipeline 7 and the refrigerant pipeline 6 for regulating the temperature of the refrigerant medium. The ethylene glycol evaporator 4 is also connected to a heat medium station, and the heat medium station supplies high-temperature heat medium medium to the ethylene glycol evaporator 4.

[0023] During the direct spinning of the melt, the polyester device is correspondingly connected to two sets of direct spinning melt conveying systems 1. Each set of direct spinning melt conveying systems 1 has three booster pumps 3 and three melt coolers 2. Under the action of the heat medium pump 13, the heat medium medium and the refrigerant medium between the heat medium pipeline 6 and the refrigerant pipeline 6 circulate. The refrigerant medium generated by the heat exchange of the ethylene glycol evaporator 4 is adjusted to a suitable temperature with the heat medium medium and then transported to the melt cooler 2 to cool the melt; the heat medium medium generated after the heat exchange of the melt cooler 2 is transported to the ethylene glycol evaporator 4 to heat the ethylene glycol. The heat generated after the heat exchange of the melt cooler 2 is reused for the ethylene glycol evaporator 4 to reduce energy loss and lower production costs. At the same time, the refrigerant medium generated after heating the ethylene glycol evaporator 4 is used to cool the melt cooler 2, eliminating the need for separate transportation and configuration of refrigerant, thus reducing costs.

[0024] During actual use, the temperature of the heat medium medium generated after the heat exchange of the melt cooler 2 cannot meet the temperature requirements of the ethylene glycol evaporator 4. Therefore, high-temperature heat medium needs to be supplemented from the heat medium station to meet the requirements of the ethylene glycol evaporator 4. The temperature of the generated refrigerant medium is relatively low and needs to be mixed with the heat medium medium and transported to the melt cooler 2. When needed, the high-temperature heat medium medium from the heat medium station can participate in the mixing ratio with the refrigerant medium.

[0025] Three melt coolers 2 are configured in a single set of direct spinning melt conveying system 1. The heat medium pipeline 6 and the refrigerant pipeline 6 of one ethylene glycol evaporator 4 of the polyester device are respectively connected to six melt coolers 2 in two sets of direct spinning melt conveying systems 1. One set of polyester devices is configured with one ethylene glycol evaporator 4, and one set of polyester devices is connected to two sets of direct spinning melt conveying systems 1. Therefore, one ethylene glycol evaporator 4 is directly connected to six melt coolers 2 to realize the cyclic use of the refrigerant medium and the heat medium medium.

[0026] The structure of the regulating valve group is as follows: on the refrigerant pipeline 6 upstream of the connection between the refrigerant pipeline 6 and the regulating pipeline 7, a globe valve 9, a pneumatic regulating valve 10, and a globe valve 9 are successively arranged. A branch pipe 11 is arranged in parallel on the refrigerant pipeline 6 outside the two globe valves 9, and a globe valve 9 is also arranged on the branch pipe 11; on the regulating pipeline 7 upstream of the connection between the refrigerant pipeline 6 and the regulating pipeline 7, a globe valve 9, a pneumatic regulating valve 10, and a globe valve 9 are successively arranged. A branch pipe 11 is arranged in parallel on the regulating pipeline 7 outside the two globe valves 9, and a globe valve 9 is also arranged on the branch pipe 11. Since the melt temperatures and melt flow rates corresponding to the six melt coolers 2 in the two direct spinning melt conveying systems 1 are different, and the temperature requirements for the refrigerant medium required for cooling the melt are different, the regulating valve group is used to mix part of the heat medium into the refrigerant medium to adjust the temperature of the refrigerant medium and then transport it into the melt cooler 2, so that the temperature regulation of the melt is more stable and meets the process requirements. Among them, the regulating valve group is provided with a pneumatic regulating valve 10 on the regulating pipeline 7 and the refrigerant pipeline 6 to adjust the conveying flow rates of the refrigerant medium and the heat medium. The globe valve 9 is arranged at both ends of the pneumatic regulating valve 10 and is used to close when the pneumatic regulating valve 10 fails, so as to facilitate the replacement and maintenance of the pneumatic regulating valve 10. In addition, the design of the branch pipe 11 ensures that during the replacement and maintenance of the pneumatic regulating valve 10, the heat medium and the refrigerant medium can be transported through the branch pipe 11 to ensure the normal and continuous operation of the system.

[0027] A refrigerant low-discharge pipe 8 is arranged between one of the globe valves 9 and the pneumatic regulating valve 10 on the refrigerant pipeline 6 and the regulating pipeline 7, and a discharge valve 12 is arranged on the refrigerant low-discharge pipe 8. During normal use, if there is too much refrigerant medium resulting in overcooling of the melt cooler 2, it can be discharged outward through the refrigerant low-discharge pipe 8. At the same time, the heat medium can be replenished into the ethylene glycol evaporator 4 to achieve the balance of the refrigerant medium and the heat medium in the system.

[0028] Valves are arranged on the heat medium pipeline 6 at both ends of the heat medium pump 13. A bypass 14 is arranged in parallel on the heat medium pipeline 6 outside the valves at both ends of the heat medium pump 13, and valves, a heat medium pump 13, and valves are successively arranged on the bypass 14. The bypass 14 is arranged on the heat medium pipeline 6, and the heat medium pump 13 on the bypass 14 is used as a standby. When the heat medium pump 13 on the heat medium pipeline 6 fails, the heat medium pump 13 on the bypass 14 can be used for transportation to ensure the stable operation of the system.

[0029] A method for cooling a melt using the above melt cooling device. In a polyester plant, a refrigerant pipeline 6 on an ethylene glycol evaporator 4 in an ethylene glycol steam injection system conveys a refrigerant medium to six melt coolers 2 in two direct spinning melt conveying systems 1. Heat exchange occurs in the melt coolers 2 to cool the melt. The refrigerant medium is heated to form a heat medium, and the heat medium is conveyed through a heat medium pipeline 6 to the ethylene glycol evaporator 4 to heat the ethylene glycol. The heat medium is cooled to form a refrigerant medium, and the above process is repeated. Among them, the proportion of the refrigerant medium and the heat medium entering the refrigerant pipeline 6 is adjusted through a regulating valve group to adjust the temperature of the refrigerant medium entering the melt cooler 2 to meet the requirements for melt cooling.

[0030] Application Example 1:

[0031] Specifically, taking the production of semi-dull FDY white yarn 65 dtex / 24F as an example:

[0032] After the polyester melt is discharged from the discharge pump at the outlet of the final polymerization kettle of the polyester plant, it is conveyed to the spinning device through the melt conveying system, and then extruded through the spinneret holes on the spinneret of the spinning device and cooled by ring blowing to obtain a series of FDY filament products in various specifications according to the FDY spinning process. The intrinsic viscosity of the melt is controlled at 0.625 dL / g, the terminal carboxyl group is controlled at 43 mol / t, the diethylene glycol content is controlled at 1.50%, and the melt temperature in the spinning box is controlled at 288°C.

[0033] The main parameters of the cooling device for the direct spinning melt conveying system 1 and the melt cooler 2 are as follows: the melt temperature before the booster pump 3 is 283°C, the melt pressure after the booster pump 3 is 190 bar, the melt temperature after the booster pump 3 is 287°C, the melt temperature after the cooler is 278°C, the temperature of the heat medium in the heat medium station is 315°C, the working pressure of the ethylene glycol evaporator 4 is 150 kPa, the temperature of the heat medium after heat exchange in the melt cooler 2 is 277°C, the temperature of the refrigerant medium after heat exchange in the ethylene glycol evaporator 4 is 210°C, and the temperature of the refrigerant medium entering the cooler after adjustment with the heat medium is 271°C or 272°C.

[0034] The main parameters of the FDY process are as follows: spinning temperature 288°C, ring blowing cooling temperature 23°C, air pressure 35 Pa, winding speed of GR1 2090 m / min, GR2 2110 m / min, GR3 2160 m / min, GR4 4985 m / min, GR5 4991 m / min, GR6 4999 m / min, GR7 5008 m / min, GR8 4998 / min, temperature of GR2 51°C, temperature of GR3 55°C, temperature of GR4 137°C, temperature of GR5 137°C, temperature of GR6 137°C, winding speed 5000 m / min.

[0035] The measured main quality indicators of the finally produced semi-dull FDY white yarn 65dtex / 24F product are as follows: linear density 65.05dtex, breaking strength 4.46 CN / dtex, breaking strength CV value 1.81, elongation 31.06%, breaking elongation CV value 4.78, 10% tenacity 211.36 g, evenness CV value 0.87, oil content 1.02%, boiling water shrinkage rate 7.02%, staining gray scale above 4.5 levels. The equipment runs stably, and the product quality indicators meet the requirements. Under normal operating conditions, through comprehensive calculations from aspects such as cost savings in terms of equipment reduction, electricity savings for equipment operation, and the value of heat medium heat exchange and reuse, compared with the same-specification products produced by the direct method in the traditional cooling scheme, the ton consumption index decreases by about 6.8 yuan. Calculated based on an annual production capacity of 400,000 tons, the production cost decreases by about 2.72 million yuan per year. This utility model realizes a double reduction in equipment investment and production energy consumption costs, meeting the development needs of new quality productivity for high-quality and low-energy-consuming production process technologies in production.

[0036] Application Example 2:

[0037] Specifically, taking the production of semi-dull FDY colored yarn 50dtex / 48F product as an example:

[0038] After the polyester melt is discharged from the discharge pump at the outlet of the final polymerization kettle of the polyester plant, it is sent to the spinning device through the melt conveying system, and then extruded through the spinneret holes on the spinneret plate of the spinning device and cooled by ring blowing to obtain a series of FDY filament products of different specifications according to the FDY spinning process. The melt intrinsic viscosity is controlled at 0.625 dL / g, the terminal carboxyl group is controlled at 43 mol / t, the diethylene glycol content is controlled at 1.50%, and the melt temperature in the spinning box is controlled at 287 °C. The intrinsic viscosity of the masterbatch is 0.370 dL / g, the melting point is 254 °C, and the on-line addition ratio is 3.0%.

[0039] The main parameters of the cooling device for the direct spinning melt conveying system 1 and the melt cooler 2 are as follows: the melt temperature before the booster pump 3 is 282 °C, the melt pressure after the booster pump 3 is 179 bar, the melt temperature after the booster pump 3 is 286 °C, the melt temperature after the cooler is 278 °C, the heat medium temperature of the heat medium station is 315 °C, the working pressure of the ethylene glycol evaporator 4 is adjusted at 150 kPa, the heat medium temperature after heat exchange of the melt cooler 2 is 277 °C, the refrigerant medium temperature after heat exchange of the ethylene glycol evaporator 4 is 210 °C, and the refrigerant medium temperatures of 272 °C and 273 °C after being adjusted with the heat medium and then sent to the melt cooler 2.

[0040] The main parameters of the FDY process are as follows: spinning temperature 287 °C, ring blowing cooling temperature 23 °C, air pressure 28 Pa, winding speed of GR1 2060 m / min, speed of GR2 2080 m / min, speed of GR3 2330 m / min, speed of GR4 4486 m / min, speed of GR5 4498 m / min, speed of GR6 4505 m / min, speed of GR7 4516 m / min, speed of GR8 4530 / min, temperature of GR2 58 °C, temperature of GR3 60 °C, temperature of GR4 131 °C, temperature of GR5 131 °C, temperature of GR6 131 °C, winding speed 4520 m / min.

[0041] The measured main quality indicators of the finally produced semi-dull FDY colored yarn 50 dtex / 48F product are as follows: linear density 50.10 dtex, breaking strength 4.18 CN / dtex, CV value of breaking strength 1.52, elongation 33.14%, CV value of breaking elongation 4.86, 10% strength 150.61 g, CV value of evenness 1.32, oil content 1.05%, boiling water shrinkage rate 6.98%, staining grey scale 4.5 grades. The equipment runs stably, and the product quality indicators meet the requirements. Under normal operating conditions, through comprehensive calculations from aspects such as saving funds in terms of equipment reduction, saving funds for equipment operation electricity, and the value of heat medium heat exchange and reuse, compared with the tonnage consumption index of the same specification product produced by the direct method in the traditional design cooling scheme, it drops by about 7.2 yuan. Calculated based on an annual production capacity of 400,000 tons, the production cost drops by about 2.88 million yuan per year. This utility model realizes a double reduction in equipment investment and production energy consumption costs, meeting the development needs of production for new quality productivity of high-quality and low-energy consumption production process technologies.

[0042] In the description of this application, it should be understood that the orientation or positional relationship indicated by terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation to this application. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of this application, "a plurality" means two or more, unless otherwise clearly and specifically defined.

[0043] In the description of the present application, it should be noted that unless otherwise clearly defined and limited, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0044] In the present application, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the case where the first and second features are not in direct contact but in contact through additional features therebetween. Moreover, the first feature being "above", "over", and "on top of" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "below", and "beneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely means that the horizontal height of the first feature is less than that of the second feature.

[0045] The above are only the preferred embodiments of the present utility model, and do not impose any formal limitations on the present utility model. Although the present utility model has been disclosed above with the preferred embodiments, it is not intended to limit the present utility model. Any person skilled in the art can make some changes or modifications using the disclosed technical content above to form equivalent embodiments with equivalent changes. However, as long as it does not depart from the technical content of the present utility model, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present utility model still fall within the scope of the technical solution of the present utility model.

Claims

1. A melt cooling device for a direct spinning melt conveying system, in which a melt cooler is provided on the conveying pipeline in the direct spinning melt conveying system, and the characteristics are as follows: It also includes the ethylene glycol evaporator of the polyester plant. A heat medium pipeline and a refrigerant pipeline are arranged on the ethylene glycol evaporator. The refrigerant pipeline and the heat medium pipeline are connected to the melt cooler. A heat medium pump is arranged on the heat medium pipeline. The heat medium pipeline is connected to the refrigerant pipeline corresponding to each melt cooler through an adjustment pipeline. A regulating valve group is arranged at the connection of the adjustment pipeline and the refrigerant pipeline for regulating the temperature of the refrigerant medium. The ethylene glycol evaporator is also connected to a heat medium station, and the heat medium station supplies high-temperature heat medium to the ethylene glycol evaporator.

2. The melt cooling device of a direct spinning melt conveying system according to claim 1, characterized in that: Three melt coolers are configured in a single set of direct spinning melt conveying system. The heat medium pipeline and the refrigerant pipeline of an ethylene glycol evaporator of the polyester plant are respectively connected to six melt coolers in two sets of direct spinning melt conveying systems.

3. The melt cooling device of a direct spinning melt conveying system according to claim 1 or 2, characterized in that: The structure of the regulating valve group is as follows: A stop valve, a pneumatic regulating valve, and a stop valve are successively arranged on the refrigerant pipeline upstream of the connection of the refrigerant pipeline and the adjustment pipeline. A branch pipe is arranged in parallel on the refrigerant pipeline outside the two stop valves, and a stop valve is also arranged on the branch pipe; A stop valve, a pneumatic regulating valve, and a stop valve are successively arranged on the adjustment pipeline upstream of the connection of the refrigerant pipeline and the adjustment pipeline. A branch pipe is arranged in parallel on the adjustment pipeline outside the two stop valves, and a stop valve is also arranged on the branch pipe.

4. The melt cooling device of a direct spinning melt conveying system according to claim 3, characterized in that: A refrigerant low discharge pipe is arranged between one of the stop valves and the pneumatic regulating valve on the refrigerant pipeline and the adjustment pipeline, and a discharge valve is arranged on the refrigerant low discharge pipe.

5. The melt cooling device of a direct spinning melt conveying system according to claim 1, characterized in that: at Valves are arranged on the heat medium pipelines at both ends of the heat medium pump. A bypass is arranged in parallel on the heat medium pipelines outside the valves at both ends of the heat medium pump, and valves, a heat medium pump, and valves are also successively arranged on the bypass.

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