Efficient polyester chip heating system

Abstract

The utility model discloses an efficient polyester chip heating system which comprises a chip heater, a feeding rotary valve, a discharging rotary valve, a circulating fan, a bag filter and a nitrogen heater which are connected in sequence. The slice heater is a tube type heat exchanger, slices are directly heated through a heating medium, a thermometer is arranged at a discharging port to adjust the flow of the heating medium, and accurate temperature control is achieved. And dust generated in the heating process is pumped to a bag filter by a circulating fan, is filtered by a PTFE (Polytetrafluoroethylene) membrane filter element, and is heated to 180-220 DEG C by a nitrogen heater for recycling. The pressure difference of the filter element is monitored through a nitrogen differential pressure gauge, and pulse back flushing is triggered to remove dust. A feeding rotary valve and a discharging rotary valve are synchronously controlled by a double-gate pneumatic stop valve, and the pressure of the system is kept stable in combination with a nitrogen pressure regulating valve. The device integrates heating medium direct heating, nitrogen circulation dust removal and intelligent temperature control technologies, solves the problems of redundancy, high energy consumption and insufficient dust control of traditional computing equipment, and is suitable for a large-scale polyester solid phase polycondensation process.

Description

Technical Field

[0001] This utility model relates to the field of polyester solid-phase polycondensation technology, specifically to a high-efficiency polyester chip heating system. Background Technology

[0002] The conventional polyester solid-state polycondensation process has two chip processing units, including a chip pre-crystallization unit and a chip heating unit.

[0003] In the solid-phase polycondensation (SSP) process of polyester, traditional heating systems, which use segmented electric heating or heat medium circulation heating, require multiple devices such as preheaters and heaters. The connection between the devices is cumbersome and occupies a large space, resulting in high installation and maintenance costs. At the same time, nitrogen circulation systems generally suffer from heat loss, requiring continuous replenishment of fresh nitrogen to maintain pressure balance, resulting in low energy utilization. In addition, the fine dust generated during the chip heating process easily adheres to the inner wall of the pipe or diffuses with the airflow. Existing filtration devices have low filtration accuracy and poor backflushing efficiency, which can easily cause pipe blockage and environmental pollution. More importantly, the traditional system relies on the open-loop regulation mode of a single temperature sensor, which makes it difficult to respond to chip temperature fluctuations in real time, leading to local overheating or uneven heating, which seriously affects the stability of chip quality.

[0004] Therefore, how to develop a new type of high-efficiency polyester chip heating system that simplifies the heating process and reduces dust while increasing production capacity has become an urgent problem to be solved. Utility Model Content

[0005] The purpose of this invention is to provide a high-efficiency polyester chip heating system. Through the synergistic design of direct heating with heat transfer enhanced by nitrogen circulation, it solves the technical problems of redundant equipment, high energy consumption, insufficient dust control, and lagging temperature regulation in traditional systems.

[0006] The technical solution of this utility model to solve the above-mentioned technical problems is as follows: a high-efficiency polyester chip heating system, including a chip heater, wherein the inlet of the chip heater is connected to the outlet of the feed valve; and the inlet of the feed valve is connected to a chip supply device.

[0007] The outlet of the slice heater is connected to the inlet of the discharge rotary valve; the outlet of the discharge rotary valve is connected to the pneumatic conveying pipeline.

[0008] The dust discharge port at the top of the slice heater is connected to the air inlet of the circulating fan; the air outlet of the circulating fan is connected to the air inlet of the bag filter through a pipe; the air outlet of the bag filter is connected to the air inlet of the nitrogen heater through a pipe; and the air outlet of the nitrogen heater is connected to the nitrogen inlet at the bottom of the slice heater through a pipe.

[0009] As a preferred embodiment of a high-efficiency polyester chip heating system, the chip heater is a shell-and-tube heat exchanger with a chip housing space inside the cavity; the shell side of the chip heater is provided with a heat medium channel, and a heat medium regulating valve is provided on the heat medium circuit channel;

[0010] As a preferred embodiment of a high-efficiency polyester chip heating system, a chip thermometer is provided at the outlet of the chip heater; the opening of the heat medium regulating valve is adjusted by the parameters of the chip thermometer.

[0011] As a preferred embodiment of a high-efficiency polyester chip heating system, a bypass pipe is provided between the air inlet pipe and the air outlet pipe of the bag filter; the bypass pipe is equipped with a nitrogen differential pressure gauge; the nitrogen differential pressure gauge is used to monitor the pressure difference of the bag filter.

[0012] As a preferred embodiment of a high-efficiency polyester chip heating system, the bag filter's outlet pipe is equipped with a nitrogen exhaust regulating valve and a nitrogen replenishment regulating valve; a nitrogen pressure gauge is installed on the pipe between the nitrogen replenishment regulating valve and the nitrogen heater; the nitrogen replenishment regulating valve is adjusted according to the data from the nitrogen pressure gauge.

[0013] As a preferred embodiment of a high-efficiency polyester chip heating system, a nitrogen thermometer is provided between the nitrogen heater and the bottom nitrogen inlet of the chip heater; the nitrogen thermometer is used to monitor the temperature of the nitrogen after it has been heated by the nitrogen heater.

[0014] As a preferred embodiment of a high-efficiency polyester chip heating system, both the feed valve and the discharge valve are double-gate pneumatic shut-off valves, and the feed valve and the discharge valve are synchronously controlled by the same pneumatic actuator.

[0015] The beneficial effects of this utility model are as follows:

[0016] First, the structure is integrated. It adopts a collaborative architecture of direct heating of heat medium and nitrogen circulation to enhance heat transfer, integrating heating, conveying and filtering functional modules, eliminating the need for multiple stages of equipment such as preheaters and coolers in traditional systems, greatly reducing the number of equipment and the space occupied, and reducing the complexity of installation and maintenance.

[0017] Second, it boasts high efficiency and energy-saving characteristics. Heat exchange is achieved through direct contact between the heat transfer medium and the wafers, reducing intermediate heat loss. The nitrogen circulation system is equipped with a waste heat recovery device, improving thermal energy utilization and significantly reducing overall energy consumption compared to traditional processes.

[0018] Third, ultra-clean dust removal technology. Equipped with high-precision filter components (such as PTFE membrane filter elements), it effectively intercepts dust from the filter chips; combined with a differential pressure self-triggered backflushing system, it achieves automatic cleaning of the filter elements, maintains high-efficiency filtration performance, and the dust emission concentration is far below the industry environmental protection standards.

[0019] Fourth, the intelligent temperature control system. Based on a closed-loop control system using multi-sensor data fusion, it adjusts the heat transfer fluid flow and nitrogen circulation parameters in real time to suppress temperature fluctuations, ensure uniform heating of the slices, and avoid quality defects caused by local overheating.

[0020] Fifth, safety and environmental performance. It integrates online oxygen content monitoring and nitrogen pressure interlock protection to prevent oxidation reactions; energy consumption is reduced through process optimization, meeting the requirements of green manufacturing and clean production. Attached Figure Description

[0021] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0022] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0023] Figure 1 This is a schematic diagram of a high-efficiency polyester chip heating system provided in an embodiment of the present invention.

[0024] In the diagram, 1. Slice heater; 2. Feed rotary valve; 3. Discharge rotary valve; 4. Circulating fan; 5. Bag filter; 6. Nitrogen heater; 7. Heat medium regulating valve; 8. Nitrogen exhaust regulating valve; 9. Nitrogen replenishment regulating valve; 10. Slice thermometer; 11. Nitrogen pressure gauge; 12. Nitrogen differential pressure gauge; 13. Nitrogen thermometer. Detailed Implementation

[0025] To make the above-mentioned objects, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0027] See Figure 1 This utility model provides a high-efficiency polyester chip heating system, including a chip heater 1, the inlet of which is connected to the outlet of a feed valve 2; the inlet of the feed valve 2 is connected to a chip supply device.

[0028] Specifically, the feeding rhythm of the slice supply device is controlled by opening and closing the feed rotary valve 2, ensuring that the slices enter the slice heater 1 continuously and uniformly. The feed rotary valve 2 is pneumatically driven and has rapid opening and closing and sealing performance, preventing dust from overflowing during the feeding process and reducing heating fluctuations caused by uneven feeding.

[0029] The outlet of the slice heater 1 is connected to the inlet of the discharge valve 3; the outlet of the discharge valve 3 is connected to the pneumatic conveying pipeline.

[0030] Both the feed rotary valve 2 and the discharge rotary valve 3 are double-gate pneumatic shut-off valves, synchronously controlled by the same pneumatic actuator. The double-gate design creates a double seal, and the pneumatic actuator opens and closes both valves simultaneously, preventing material leakage due to single-valve failure. The valve sealing surfaces are made of hard alloy weld overlay, offering wear resistance and a lifespan of up to 100,000 opening and closing cycles, meeting the demands of high-frequency industrial production. After the slices have finished heating, the discharge rotary valve 3 opens, pushing the slices to the downstream polycondensation reactor via a pneumatic conveying pipeline. The pneumatic conveying utilizes nitrogen as a carrier, preventing oxygen contamination and oxidation reactions, and reducing static electricity generated by slice friction through fluidization.

[0031] The dust discharge port at the top of the slice heater 1 is connected to the air inlet of the circulating fan 4; the air outlet of the circulating fan 4 is connected to the air inlet of the bag filter 5 through a pipe.

[0032] Specifically, the fine dust generated during the slicing heating process rises with the nitrogen gas to the top exhaust port, where the circulating fan 4 draws the dust-laden nitrogen gas to the bag filter 5. The fan airflow is adjusted by frequency converter to match the slicing processing volume, ensuring that dust collection efficiency and system pressure are balanced.

[0033] The air volume of the circulating fan 4 is 1200m³. 3 / h, wind pressure is 12kPa; large air volume of circulating fan 4 (1200m³ / h) 3 The combination of high pressure (12kPa) and high air pressure ( / h) can meet the dust conveying needs while avoiding pipeline blockage.

[0034] The outlet of the bag filter 5 is connected to the inlet of the nitrogen heater 6 via a pipe; the outlet of the nitrogen heater 6 is connected to the bottom nitrogen inlet of the slice heater 1 via a pipe.

[0035] Specifically, the nitrogen gas purified by the bag filter 5 returns to the nitrogen heater 6, where it is heated to a set temperature (typically 180-220℃) by electric heating or steam heating, and then fed into the bottom of the slice heater 1. The hot nitrogen gas forms an upward airflow in the gap between the slices, achieving countercurrent heating and improving heat exchange efficiency.

[0036] The nitrogen heater 6 has a heat load of 2kW. The 2kW nitrogen heater uses an electric heating element with a thermal efficiency >90%, resulting in significant energy savings.

[0037] In one possible embodiment, the slice heater 1 is a shell-and-tube heat exchanger with a slice accommodating space inside the cavity; the shell side of the slice heater 1 is provided with a heat medium channel, and a heat medium regulating valve 7 is provided on the heat medium circuit channel.

[0038] The slice heater 1 is made of 304 stainless steel and has a heat exchange area of ​​1000 m². 2 304 stainless steel is corrosion-resistant and has high thermal conductivity (approximately 16 W / m·K), with a lifespan of 1000m. 2 The heat exchange area ensures a processing capacity of 5t / h per unit time.

[0039] Specifically, the shell-and-tube design allows the slices to be statically stacked in the tube side, while the heat transfer medium (such as heat transfer oil or molten salt) circulates in the shell side. The heat transfer medium regulating valve 7 adjusts the flow rate based on the feedback signal from the slice thermometer 10 to maintain a stable slice temperature. The tube walls are polished to reduce slice adhesion and facilitate cleaning.

[0040] In one possible embodiment, a slice thermometer 10 is provided at the outlet of the slice heater 1; the parameters of the slice thermometer 10 adjust the opening of the heat medium regulating valve 7.

[0041] Specifically, thermometer 10 monitors the temperature of the discharged slices in real time and uses a PID algorithm to control the opening of the heat medium regulating valve 7. When the temperature deviates from the set value, the system dynamically adjusts the heat medium flow rate; for example, it reduces the heat medium flow rate when the temperature rises and increases it when the temperature falls, achieving precise temperature control of ±1℃.

[0042] In one possible embodiment, a bypass pipe is provided between the air inlet pipe and the air outlet pipe of the bag filter 5; the bypass pipe is equipped with a nitrogen differential pressure gauge 12; the nitrogen differential pressure gauge 12 is used to monitor the pressure difference of the bag filter 5.

[0043] Specifically, during normal filtration, nitrogen gas enters the outlet pipe through the filter bag. When dust accumulates on the surface of the filter bag, causing the pressure difference to increase, the nitrogen differential pressure gauge 12 reaches a set threshold (usually set at 800-1200 Pa). This triggers the backflushing system of the bag filter 5, which backflushes the filtered dust to the lower outlet for discharge. The backflushing system uses pulsed compressed air (0.5-0.8 MPa, at 5-10 minute intervals) to instantly release high-pressure airflow and shake off the dust from the outer wall of the filter bag. The backflushing cycle and duration are intelligently adjusted according to the amount of dust to ensure that the filtration efficiency is always >99.9% and the dust emission concentration is <1 mg / m³. 3 The bypass pipeline is activated during backflushing to maintain uninterrupted nitrogen circulation and prevent system pressure fluctuations.

[0044] In one possible embodiment, the outlet pipe of the bag filter 5 is provided with a nitrogen exhaust regulating valve 8 and a nitrogen replenishment regulating valve 9; a nitrogen pressure gauge 11 is provided on the pipe between the nitrogen replenishment regulating valve 9 and the nitrogen heater 6; the nitrogen replenishment regulating valve 9 is adjusted according to the data of the nitrogen pressure gauge 11.

[0045] The external discharge regulating valve 8 controls the nitrogen discharge, while the replenishment regulating valve 9 dynamically replenishes fresh nitrogen based on feedback from the pressure gauge 11. Together, they maintain stable system pressure (typically 0.5-0.8 MPa), ensuring the continuity of slice delivery and filtration processes, while preventing outside air from infiltrating and disrupting the inert environment.

[0046] In one possible embodiment, a nitrogen thermometer 13 is provided between the nitrogen heater 6 and the bottom nitrogen inlet of the slice heater 1; the nitrogen thermometer 13 is used to monitor the temperature of the nitrogen after it has been heated by the nitrogen heater 6.

[0047] Specifically, thermometer 13 monitors the nitrogen temperature entering the slice heater 1 in real time. If the temperature is abnormal (e.g., below 150℃ or above 250℃), the system automatically cuts off the heat transfer medium supply and issues an alarm. This dual protection mechanism prevents slice condensation due to low temperatures or thermal degradation caused by high temperatures.

[0048] The working principle of this utility model is as follows:

[0049] First, the polyester chips are fed and conveyed: the polyester chips enter the tube side cavity of the chip heater 1 through the feed rotary valve 2. The rotary valve is a double-gate pneumatic shut-off valve, which is opened and closed synchronously by the same pneumatic actuator to ensure the sealing and continuity of the feed. The heated chips are discharged through the discharge rotary valve 3 and sent to the downstream polycondensation reactor through a pneumatic conveying pipeline. Nitrogen is used as an inert carrier throughout the process to avoid oxidation reaction.

[0050] Second, direct heating by the heat transfer medium: The slice heater 1 is a shell-and-tube heat exchanger. The heat transfer medium (such as heat transfer oil) circulates in the shell side and transfers heat to the slices through the tube walls. The slice thermometer 10 at the outlet monitors the temperature in real time and adjusts the opening of the heat transfer medium regulating valve 7 through a PID algorithm to maintain a stable slice temperature (±1℃).

[0051] Third, dust collection and filtration: Dust generated during the heating process rises with the nitrogen gas to the top of the slice heater 1 and is then drawn to the bag filter 5 by the circulating fan 4. The bag filter 5 intercepts dust through a PTFE membrane filter element, with a filtration accuracy of ≤5μm. When the nitrogen differential pressure gauge 12 detects a pressure difference >1200Pa, it triggers the pulse backflushing system to remove dust from the surface of the filter element.

[0052] Fourth, nitrogen circulation and energy recovery: The filtered clean nitrogen is reheated to 180-220℃ by the nitrogen heater 6, forming a closed-loop circulation. The nitrogen heater has a built-in thermometer 13, which automatically cuts off the heat source in case of abnormality. The nitrogen exhaust regulating valve 8 and the replenishment regulating valve 9 are dynamically adjusted according to the data from the pressure gauge 11 to maintain a stable system pressure (0.5-0.8MPa) and ensure an inert environment.

[0053] Fifth, valve interlocking: Feed rotary valve 2, discharge rotary valve 3, and the backflushing system are started and stopped synchronously through the same pneumatic actuator, reducing manual intervention. Data fusion from multiple temperature, pressure, and differential pressure sensors enables fully automated control of the heating, filtration, and conveying process, reducing energy consumption and dust emissions (<1mg / m³). 3 ).

[0054] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0055] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A high-efficiency polyester chip heating system, characterized in that, Includes a slicing heater (1), the inlet of which is connected to the outlet of a feed rotary valve (2); the inlet of the feed rotary valve (2) is connected to a slicing supply device; The outlet of the slice heater (1) is connected to the inlet of the discharge rotary valve (3); the outlet of the discharge rotary valve (3) is connected to the pneumatic conveying pipeline. The dust discharge port at the top of the slice heater (1) is connected to the air inlet of the circulating fan (4); the air outlet of the circulating fan (4) is connected to the air inlet of the bag filter (5) through a pipe; the air outlet of the bag filter (5) is connected to the air inlet of the nitrogen heater (6) through a pipe; and the air outlet of the nitrogen heater (6) is connected to the nitrogen inlet at the bottom of the slice heater (1) through a pipe.

2. The high-efficiency polyester chip heating system according to claim 1, characterized in that, The slice heater (1) is a shell-and-tube heat exchanger with a slice housing space inside the cavity; the shell side of the slice heater (1) is provided with a heat medium channel, and a heat medium regulating valve (7) is provided on the heat medium circuit channel.

3. The high-efficiency polyester chip heating system according to claim 2, characterized in that, The slice heater (1) is equipped with a slice thermometer (10) at its outlet; the opening of the heat medium regulating valve (7) is adjusted by the parameters of the slice thermometer (10).

4. The high-efficiency polyester chip heating system according to claim 1, characterized in that, A bypass pipe is provided between the air inlet pipe and the air outlet pipe of the bag filter (5); the bypass pipe is equipped with a nitrogen differential pressure gauge (12); the nitrogen differential pressure gauge (12) is used to monitor the pressure difference of the bag filter (5).

5. The high-efficiency polyester chip heating system according to claim 4, characterized in that, The bag filter (5) is equipped with a nitrogen exhaust regulating valve (8) and a nitrogen replenishment regulating valve (9) on its outlet pipe; a nitrogen pressure gauge (11) is provided on the pipe between the nitrogen replenishment regulating valve (9) and the nitrogen heater (6); the nitrogen replenishment regulating valve (9) is adjusted according to the data of the nitrogen pressure gauge (11).

6. The high-efficiency polyester chip heating system according to claim 1, characterized in that, A nitrogen thermometer (13) is provided between the nitrogen heater (6) and the bottom nitrogen inlet of the slice heater (1); the nitrogen thermometer (13) is used to monitor the temperature of the nitrogen after it is heated by the nitrogen heater (6).

7. The high-efficiency polyester chip heating system according to claim 1, characterized in that, The feed rotary valve (2) and the discharge rotary valve (3) are both double-gate pneumatic shut-off valves, and the feed rotary valve (2) and the discharge rotary valve (3) are synchronously controlled by the same pneumatic actuator.

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