A continuous drying and cooling device for resin particles

Abstract

This invention provides a continuous drying and cooling device for resin particles, comprising a carrier gas generator, a drying circulation system, and a cooling circulation system. The drying circulation system includes a drying tower, a first powder collector, a dehumidifying dryer, a first fan, and a gas heater. The cooling circulation system includes a cooling tower, a second powder collector, a second fan, and a gas cooler. The drying tower and the cooling tower are connected by pipelines to achieve continuous drying and cooling of the material. The drying tower and the cooling tower are equipped with multiple layers of staggered inclined trays, with a support shaft in the center of each tray. The top and bottom of the towers are equipped with sieves of different mesh sizes to achieve particle grading and uniform airflow distribution. This invention achieves a continuous, efficient, and low-wear drying and cooling process for resin particles through a closed-loop carrier gas circulation, a multi-stage inclined tray structure, and an integrated drying and cooling design.

Description

Technical Field

[0001] This utility model relates to the field of resin processing technology, specifically to a continuous drying and cooling device for resin particles. Background Technology

[0002] Polymer materials such as polyamide (PA), polyester (PET), and polycarbonate (PC) must be dried before processing and use to control their moisture content within a certain range, thus preventing problems such as hydrolysis, bubbling, and degradation during subsequent high-temperature processing. Common drying methods include vacuum drum drying, fluidized bed drying, and tower drying.

[0003] However, the following problems still exist in the existing technology:

[0004] 1. Although vacuum drum drying equipment can provide a low-humidity environment, it operates intermittently, resulting in low production efficiency, long heating and cooling cycles, and low heat exchange efficiency. For example, a vacuum drum drying device disclosed in existing patent CN219531390U mainly consists of a support, transmission device, shell, cavity, and vacuum system. While this device can maintain a dry environment and temperature within the drying cavity through vacuuming, due to the limitations of this equipment type, it can only operate intermittently, and the heating and cooling cycles are long. Furthermore, the severe accumulation of material within the drum cavity reduces the effective heat exchange area, leading to a long drying cycle and extremely low production efficiency.

[0005] 2. Although fluidized bed drying can be operated continuously, it has high energy consumption and a large footprint. For example, the existing patent CN220601944U proposes a new type of fluidized bed dryer, which mainly consists of a fluidized bed body, a fluidized bed shell, and a vibration device. It solves the problems of cracking, uneven internal and external temperatures, and incomplete drying during the fluidized bed drying of plastic particles. However, the hot air used as the drying carrier gas in this device is not reused, resulting in high energy consumption and poor economic efficiency. Due to the limitations of the equipment form, industrial-scale installations of this device occupy a large area. In addition, using hot air as the carrier gas has very obvious limitations for some thermally oxidizing materials.

[0006] 3. Although existing tower drying equipment has undergone structural improvements, it still suffers from problems such as severe particle wear, excessive powder generation, low hot air circulation efficiency, and poor drying uniformity. For example, the existing patent CN210832876U designs a polyester chip drying tower, which uses a discharge pipe, an air outlet pipe, a stirring main pipe, a stirring branch pipe, and a drive assembly on the tower body to achieve chip turning and drying within the tower. Although the uniformity of chip heating is improved, the equipment structure is complex, energy consumption is high, chip wear is severe, and there is a lot of powder in the product.

[0007] Therefore, it is necessary to provide an integrated drying and cooling device that can operate continuously, consumes little energy, and produces little powder, in order to overcome the shortcomings of the prior art. Utility Model Content

[0008] The purpose of this invention is to provide a continuous drying and cooling equipment for resin particles. Through a closed-loop carrier gas circulation, a multi-stage inclined tower plate structure, and an integrated drying and cooling design, it achieves a continuous, efficient, and low-wear drying and cooling process for resin particles. Moreover, the equipment has a compact structure, is easy to operate, and is suitable for drying various engineering resin plastics.

[0009] To achieve the above objectives, the present invention proposes the following technical solution:

[0010] A continuous drying and cooling device for resin particles, comprising:

[0011] A drying cycle system includes a drying tower, and a first powder collector, a dehumidifying dryer, a first fan, and a gas heater connected in sequence, wherein the inlet of the first powder collector is connected to the first air outlet of the drying tower, and the first gas outlet of the gas heater is connected to the hot gas inlet of the drying tower.

[0012] A cooling circulation system includes a cooling tower, and a second powder collector, a second fan, and a gas cooler connected in sequence, wherein the inlet of the second powder collector is connected to the second air outlet of the drying tower, and the second air outlet of the gas cooler is connected to the cold air inlet of the cooling tower.

[0013] The carrier gas generator has its outlet connected to the inlet of the gas heater and the second powder collector, respectively.

[0014] The dry material outlet of the drying tower is connected to the dry material inlet of the cooling tower via a pipeline.

[0015] As a preferred technical solution of this utility model, both the drying tower and the cooling tower include a tower body, and the tower body is provided with multiple tower plates and a support shaft for supporting the tower plates.

[0016] The support shaft is located on the central axis of the tower body;

[0017] Multiple trays are arranged in an alternating, inclined manner along the axial direction, with channels reserved between adjacent trays.

[0018] As a preferred embodiment of this utility model, the drying tower has no fewer than 50 trays, and the tilt angle of the trays is 5°-35°.

[0019] As a preferred embodiment of this utility model, the cooling tower has no fewer than 20 trays, and the tilt angle of the trays is 5°-35°.

[0020] As a preferred embodiment of this utility model, both the drying tower and the cooling tower are provided with a first sieve plate at their top, and the sieve plate has a mesh size of 20-100 mesh.

[0021] As a preferred embodiment of this utility model, the bottom tray of the drying tower is a second sieve plate;

[0022] The screen mesh size in the middle area of ​​the second screen plate is 8-15 mesh, and a discharge port is provided in the center of it;

[0023] The mesh size of the edge area of ​​the second sieve plate is 20-200 mesh.

[0024] As a preferred embodiment of this utility model, the bottommost tray of the cooling tower is a third sieve plate;

[0025] The third sieve plate has a mesh size of 20-100 and a discharge port in the center.

[0026] As a preferred embodiment of this utility model, both the drying tower and the cooling tower are provided with heat insulation jackets.

[0027] As can be seen from the above technical solution, the present invention provides a continuous drying and cooling device for resin particles. During operation, wet resin particles enter from the top of the drying tower and fall layer by layer along the tower plates under gravity, contacting the hot nitrogen gas flowing counter-currently. After drying, they are discharged from the dry material outlet and enter the top of the cooling tower via a pipeline. In the cooling tower, the dry particles contact the cold nitrogen gas counter-currently, gradually cooling before being discharged from the cold material outlet. The nitrogen gas is recycled within the system, being purified by a powder collector and dehumidification drying process before being reheated or cooled.

[0028] This invention extends material residence time and improves heat and mass exchange efficiency through a tower plate structure design; achieves particle classification and powder control through a sieve plate structure; and prevents material oxidation through inert gas circulation, ensuring product quality. The entire set of equipment has a compact structure, can achieve continuous automated operation, and is suitable for drying and cooling various engineering plastics such as polyamide, polyester, and polycarbonate.

[0029] It should be understood that all combinations of the foregoing concepts and the additional concepts described in more detail below can be considered as part of the utility model subject matter of this disclosure, provided that such concepts do not contradict each other.

[0030] The foregoing and other aspects, embodiments, and features of the present invention will be more fully understood from the following description in conjunction with the accompanying drawings. Other additional aspects of the present invention, such as features and / or beneficial effects of exemplary embodiments, will become apparent from the following description or may be learned through practice of specific embodiments according to the teachings of the present invention. Attached Figure Description

[0031] The accompanying drawings are not drawn to scale according to a true reference numeral. In the drawings, each identical or nearly identical component shown in the various figures can be denoted by the same reference numeral. For clarity, not every component is labeled in each figure. Embodiments of various aspects of the present invention will now be described by way of example and with reference to the accompanying drawings, wherein:

[0032] Figure 1 This is a schematic diagram of the continuous drying and cooling equipment of this utility model;

[0033] Figure 2 This is a schematic diagram of the structure of the second sieve plate of this utility model;

[0034] Figure 3 This is a schematic diagram of the structure of the third sieve plate of this utility model.

[0035] The meanings of the reference numerals in the figure are as follows:

[0036] 1. Drying tower, 2. Cooling tower, 3. Carrier gas generator, 4. First powder collector, 5. Drying dehumidifier, 6. First fan, 7. Gas heater, 8. Second powder collector, 9. Second fan, 10. Gas cooler, 11. First sieve plate, 12. Tower plate, 13. Third sieve plate, 14. Second sieve plate, 15. Collection hopper, 16. Support shaft. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the described embodiments of this utility model without creative effort are within the scope of protection of this utility model. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art to which this utility model pertains.

[0038] The terms "first," "second," and similar words used in this utility model patent application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, unless the context clearly indicates otherwise, the singular forms of "an," "a," or "the," etc., do not indicate a quantity limitation, but rather indicate the presence of at least one. Terms such as "comprising" or "including" indicate that the element or object preceding "comprising" encompasses the features, integrals, steps, operations, elements, and / or components listed following "comprising" or "including," and do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or collections thereof. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0039] This utility model provides a continuous drying and cooling device, the specific structure of which is as follows: Figure 1 As shown, the equipment mainly includes a drying circulation system, a cooling circulation system, and a carrier gas generator 3.

[0040] The drying circulation system includes a drying tower 1, a first powder collector 4, a dehumidifying dryer 5, a first fan 6, and a gas heater 7. The drying tower 1 is a vertical tower structure with a wet material inlet and a first air outlet at its top. Preferably, the wet material inlet is located in the middle of the top, which, together with the inclined tower plate 12, allows the material to fall evenly inside the tower. The first air outlet is located on one side of the wet material inlet and serves as the outlet for the carrier gas. At its bottom, there is a dry material outlet and a hot air inlet, which are the outlet for the dried material and the inlet for the drying hot air, respectively. Again, the dry material outlet is located in the middle, and there are several hot air inlets, which are evenly distributed along the bottom edge of the tower.

[0041] The first powder collector 4, the dehumidifier 5, the first fan 6, and the gas heater 7 are connected in sequence through pipes. At the same time, the first powder collector 4 is connected to the first air outlet through a pipe, and the first gas outlet of the gas heater 7 is connected to multiple hot gas inlets at the bottom of the drying tower through a pipe.

[0042] In this embodiment of the invention, the carrier gas can be recycled. However, because the carrier gas exiting the first air outlet carries dust and moisture after heat exchange with the resin particles, it needs to undergo dust removal and dehumidification treatment before being reintroduced into the drying tower 1. Therefore, a first powder collector 4 and a dehumidifier 5 are sequentially installed downstream of the first air outlet to remove powder and dehumidify the carrier gas, respectively. Of course, in some specific embodiments, the positions of the first powder collector 4 and the dehumidifier 5 can be interchanged, as long as dust removal and dehumidification can be achieved before the recycled carrier gas is used.

[0043] In some specific embodiments, in order to prevent the resin particles from being oxidized by the high-temperature carrier gas after heating and losing their properties, inert gases such as nitrogen are used as the carrier gas. Even after heating, the resin particles will not be oxidized, thus increasing the material applicability of the equipment.

[0044] To prolong the residence time of resin particles in the drying tower 1, in some specific embodiments, multiple inclined trays 12 are arranged inside the drying tower 1. The trays 12 are fixed to the inner wall of the tower by a support shaft 16 located on the central axis inside the tower, which extends from the bottom to the top of the tower. Figure 1 As shown, multiple trays 12 are arranged in a staggered, inclined manner along the axial direction of the tower body, with an inclination angle of 5°-35°. Channels are reserved between adjacent trays 12 for the passage of resin particles and carrier gas. Specifically, the trays 12 have a conical structure. The top tray 12 is fixedly connected to the support shaft 16 with its center point as the fixed point, and slopes downwards from the center point towards the four outer edges (one side of the inner wall of the tower). The second tray 12 below it is fixedly connected to the inner wall of the tower with its four outer edges as the fixed ends, and slopes downwards from its edges towards the center point. The third tray 12 below the second tray 12 has the same structure as the top tray 12. This sequential arrangement forms a continuously bending material flow path, extending the residence time of the material in the drying tower 1, allowing the material to fully contact the high-temperature nitrogen gas and remove moisture. Preferably, the number of trays 12 in the drying tower 1 is not less than 50 to ensure that the residence time of the resin particles in the drying tower 1 is 2-4 hours. In order to reduce the pressure drop of the drying tower 1 or the resistance to the rise of the carrier gas, a certain number of through holes can be opened on the tower plate 12. The through holes must ensure that the airflow can pass through but the resin particles cannot pass through, so that the resin particles can only fall layer by layer along the bent material flow path under their own gravity.

[0045] In some specific embodiments, a first sieve plate 11 is provided above the uppermost tray 12, and the mesh size of the first sieve plate 11 is 20-100 mesh. The first sieve plate 11 is designed to allow the airflow to carry out powder with a particle size of less than 0.2 mm, without carrying away normal resin particles.

[0046] In addition, to further remove incomplete resin particles and particles that cannot be removed by airflow entrainment, such as resin particles with defects in shape, a second sieve plate 14 is provided below the bottom tray 12. Figure 2As shown, the screen mesh size in the middle area of ​​the second sieve plate 14 is 8-15 mesh, which is used to screen out fine particles smaller than 2mm that the airflow cannot carry away. However, its sieve holes cannot allow resin particles of normal size to pass through, and it has a discharge port in the center for discharging resin particles of normal size. The screen mesh size in the edge area of ​​the second sieve plate 14 is 20-200 mesh, which is used to allow the airflow to pass through smoothly. Therefore, the hot air inlet of the drying tower 1 is correspondingly set below the screen in the edge area, and multiple hot air inlets can be evenly arranged to ensure uniform air intake and uniform distribution of airflow in the tower body.

[0047] like Figure 1 As shown, a hopper 15 is provided below the sieve holes in the middle area of ​​the second sieve plate 14 to collect fine particles falling from the sieve holes in that area. The bottom of the hopper 15 is provided with a discharge port.

[0048] When resin particles fall onto the second sieve plate 14, they move along its surface toward the central discharge port. When passing through the middle area, fine particles fall through the sieve holes in that area into the collection hopper 15 below, while resin particles of normal size continue to move toward the discharge port, thereby achieving secondary screening to remove incomplete particles, damaged particles, etc.

[0049] Among them, the gas heater 7 is an electric heating or steam heating (indirect heat exchange) heat exchanger. The dehumidifier 5 is an adsorption or condensation dehumidification device. These devices are all conventional equipment in this field, and their specific structures will not be described in detail here.

[0050] The drying process of drying tower 1 is as follows: resin particles enter drying tower 1 through wet material inlet, pass through layers of tower plates 12 under their own gravity and come into contact with hot drying nitrogen. Under the heating and drying of hot drying nitrogen, the moisture is removed step by step, and finally enters cooling tower 2 from dry material outlet at the bottom of drying tower 1. Large and fine particles in the resin particles are screened by the second screen plate at the bottom of the tower and collected and discharged by collection hopper 15.

[0051] In this process, the carrier gas, such as inert gas, exits from the first air outlet at the top of the drying tower 1 and continues to circulate and be heated under the suction of the first fan 6. However, because the outgoing airflow contains resin powder and moisture, it must pass through the first powder collector 4 to collect the powder and the drying dehumidifier 5 to remove moisture before it can be recycled.

[0052] The carrier gas generator 3 is connected to the gas heater 7 via a pipeline to provide or supplement the drying tower 1 with carrier gas such as nitrogen for hot drying, maintaining a stable airflow in the drying tower 1. The nitrogen in the drying tower 1 has a temperature of 50-200℃ and a moisture content of less than 0.1 g / Nm³. 3 .

[0053] The cooling circulation system includes a cooling tower 2, a second powder collector 8, a second fan 9, and a gas cooler 10. The cooling tower 2 is a vertical tower structure, positioned below the drying tower 1 to reduce floor space and energy consumption. This allows the dried resin particles to fall directly into the cooling tower 2 under gravity. Therefore, the dry material outlet of the drying tower 1 is connected to the dry material inlet at the top of the cooling tower 2 via a pipe, enabling continuous material transfer. The cooling tower 2 also has a second air outlet at its top and a cold material outlet and a cold air inlet at its bottom. The cold material outlet is located in the middle to discharge the cooled material; several cold air inlets are evenly distributed along the bottom edge of the cooling tower 2. The second air outlet is connected to the inlet of the second powder collector 8 via a pipe; the second powder collector 8, the second fan 9, and the gas cooler 10 are connected sequentially via pipes, with the gas cooler 10 connected to the cold air inlets via a pipe, forming the cooling circulation path.

[0054] Furthermore, the outlet of the carrier gas generator 3 is connected to the inlet of the second powder collector 8 via a pipe, and the gas inside the cooling tower 2 is circulated by the suction of the second fan 9. Of course, in other specific embodiments, the outlet of the carrier gas generator 3 can also be directly connected to the gas cooler 10, as long as the carrier gas entering the cooling tower 2 is cooled.

[0055] In this embodiment of the invention, the internal structure of the cooling tower 2 is the same as that of the drying tower 1, except that the number of tower plates 12 is different. The cooling tower 2 has at least 20 tower plates 12 to ensure that the resin particles stay in it for 20-60 minutes to achieve sufficient cooling.

[0056] Furthermore, since secondary sieving of powder and fine particles has been performed in drying tower 1, most fine particles have already been removed in drying tower 1. Therefore, only powder sieving is required in cooling tower 2. The powder at this stage is generated by the collision and friction between resin particles as they enter cooling tower 2. Therefore, a first screen 11 is also installed above the uppermost tray 12 of cooling tower 2. A third screen 13 is installed below the lowermost tray of cooling tower 2, such as... Figure 3 As shown, at this time, the third screen 13 does not need to be set with a fine particle removal area, so its mesh size is set to 20-200 mesh, and a discharge port is set in the middle for the cooled resin particles to be discharged.

[0057] The cooling process of cooling tower 2 is as follows: the dry resin particles fall through layers of tower plates 12 and come into contact with low-temperature nitrogen gas to be cooled down step by step. Finally, they flow out from the cold material outlet at the bottom of cooling tower 2 and are packaged.

[0058] Nitrogen gas exits from the second air outlet at the top of cooling tower 2, passes through the second powder collector 8 to remove powder, and is then recycled. The nitrogen temperature in cooling tower 2 is 10-50℃. Gas cooler 10 is a water-cooled or air-cooled heat exchanger.

[0059] The first powder collector 4 and the second powder collector 8 are either cyclone separators or bag filters.

[0060] In some specific embodiments, both the drying tower 1 and the cooling tower 2 are provided with heat insulation jackets, which serve to retain heat and retain cold, respectively.

[0061] In this invention, after the resin particles enter the drying tower 1, they fall under their own gravity and eventually flow out from the bottom of the cooling tower 2. Throughout the process, the flow rate and residence time of the resin particles are uniform, and the friction between the resin particles is small, resulting in less powder formation. In addition, the drying and cooling processes use inert gases such as nitrogen as carrier gases, which not only effectively prevents the resin particles from thermal oxidation and aging, but also makes the drying and cooling more uniform, resulting in a more uniform and stable moisture content of the final dried resin particles.

[0062] In this embodiment of the present invention, the carrier gas generator 3, powder collector, gas heater 7, gas cooler 10, dehumidifier 5 and other devices are all known devices in the art. The present invention does not improve their structure, but only combines them for application in this drying and cooling system. Through system structure design, continuous, efficient and low-consumption drying and cooling effects are achieved.

[0063] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Those skilled in the art to which this invention pertains can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of this invention shall be determined by the claims.

Claims

1. A continuous drying and cooling device for resin particles, characterized in that, include: The drying cycle system includes a drying tower (1), and a first powder collector (4), a dehumidifying dryer (5), a first fan (6), and a gas heater (7) connected in sequence. The inlet of the first powder collector (4) is connected to the first air outlet of the drying tower (1), and the first gas outlet of the gas heater (7) is connected to the hot gas inlet of the drying tower (1). The cooling circulation system includes a cooling tower (2), and a second powder collector (8), a second fan (9), and a gas cooler (10) connected in sequence. The inlet of the second powder collector (8) is connected to the second air outlet of the drying tower (1), and the second air outlet of the gas cooler (10) is connected to the cold air inlet of the cooling tower (2). The outlet of the carrier gas generator (3) is connected to the inlet of the gas heater (7) and the second powder collector (8), respectively. The dry material outlet of the drying tower (1) is connected to the dry material inlet of the cooling tower (2) via a pipeline.

2. The continuous drying and cooling equipment for resin particles according to claim 1, characterized in that, Both the drying tower (1) and the cooling tower (2) include a tower body, and the tower body is provided with multiple tower plates (12) and a support shaft (16) for supporting the tower plates (12). The support shaft (16) is located on the central axis of the tower body; Multiple trays (12) are arranged in an alternating and inclined manner along the axial direction, and a channel is reserved between adjacent trays (12).

3. The continuous drying and cooling equipment for resin particles according to claim 2, characterized in that, The drying tower (1) has no less than 50 trays (12), and the tilt angle of the trays (12) is 5°-35°.

4. The continuous drying and cooling equipment for resin particles according to claim 2, characterized in that, The cooling tower (2) has no fewer than 20 trays, and the trays (12) have an inclination angle of 5°-35°.

5. The continuous drying and cooling equipment for resin particles according to claim 1, characterized in that, The top of both the drying tower (1) and the cooling tower (2) is provided with a first sieve plate (11), and the mesh number of the first sieve plate (11) is 20-100 mesh.

6. The continuous drying and cooling equipment for resin particles according to claim 2, characterized in that, The bottom tray of the drying tower (1) is the second sieve plate (14). The screen mesh size in the middle area of ​​the second screen plate (14) is 8-15 mesh, and a discharge port is provided in the center of it; The mesh size of the edge area of ​​the second sieve plate (14) is 20-200 mesh.

7. The continuous drying and cooling equipment for resin particles according to claim 2, characterized in that, The bottom plate of the cooling tower (2) is the third sieve plate (13). The third sieve plate (13) has a mesh size of 20-100 and a discharge port in its center.

8. The continuous drying and cooling equipment for resin particles according to claim 1, characterized in that, Both the drying tower (1) and the cooling tower (2) are equipped with heat insulation jackets.

Images