Intermittent deep drying system and method for polyamide
Through the polyamide intermittent deep drying system, the boiling fluidized bed and vacuum rake dryer are combined with magnetic ball fluidization and vacuum drying to solve the problem of difficulty in reducing moisture in polyamide, realize the high efficiency and low energy consumption drying process, and ensure product quality.
Patent Information
- Application Number
- CN202410330328.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-21
- Publication Date
- 2025-09-23
AI Technical Summary
In the existing process, the polyamide after the reaction still contains 0.2% to 0.5% water, which is difficult to reduce to 0.001% to 0.005%, affecting the crystallinity, softening point and bonding point of the polyamide, resulting in unqualified product quality.
The polyamide intermittent deep drying system is adopted, including boiling fluidized bed, surface cooler, dehumidifier, heater and vacuum rake dryer. Through magnetic ball fluidization and vacuum drying method, the drying process is controlled in sections to achieve uniform and thorough drying.
The deep drying of polyamide is achieved, the moisture content is reduced to 0.001% to 0.005%, the product quality is improved, the energy consumption is reduced, the dust overflow and material agglomeration are avoided, and the operation is simple and controllable.
Smart Images
Figure CN120684864A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of polyamide drying and reaction, and in particular to a polyamide intermittent deep drying system and method. Background Art
[0002] In existing processes, polyamide still contains 0.2% to 0.5% moisture after the reaction. To obtain qualified polyamide, the moisture content must be reduced to 0.001% to 0.005%. Otherwise, the moisture will affect the polyamide's crystallinity, softening point, and bonding point. To ensure product quality, polyamide requires a deep drying process. Summary of the Invention
[0003] The purpose of the present invention is to provide a polyamide intermittent deep drying system and method, thereby obtaining qualified polyamide intermittent products.
[0004] To achieve the above-mentioned objectives, the present invention provides a polyamide intermittent deep drying system, which includes a boiling fluidized bed, a surface cooler, a dehydrator, a heater, and a vacuum rake dryer; the surface cooler is connected to the top of the boiling fluidized bed, the dehydrator is connected to the surface cooler, one end of the heater is connected to the dehydrator, and the other end of the heater is connected to the boiling fluidized bed; and the vacuum rake dryer is connected to the discharge port of the boiling fluidized bed.
[0005] In one embodiment, a wet material inlet and a magnetic ball inlet are further provided at the top of the boiling fluidized bed. Magnetic balls are also added into the boiling fluidized bed and enter the boiling fluidized bed through the magnetic ball inlet.
[0006] In one embodiment, a circulating cooling water outlet is provided at the top of the surface cooler, and a circulating cooling water inlet is provided at the bottom of the surface cooler; circulating cooling water is input from the bottom of the surface cooler and output from the top of the surface cooler to cool the gas discharged from the boiling fluidized bed; the surface cooler is any one of a shell and tube type, a plate type, and a fin type.
[0007] In one embodiment, a circulating fan is further provided between the heater and the water eliminator.
[0008] In one embodiment, a heat transfer oil outlet is provided at the top of the heater, and a heat transfer oil outlet is provided at the bottom of the heater; the heat transfer oil is input from the bottom of the heater and output from the top of the heater, thereby heating the gas.
[0009] In one embodiment, the boiling fluidized bed is a containerized special boiling fluidized bed, which is also provided with a thermal oil coil and a bag dust collector; the thermal oil coil is provided with thermal oil for heating and drying the wet material in the boiling fluidized bed; a magnetic ball outlet and a magnetic ball discharge valve are also provided on one side of the boiling fluidized bed.
[0010] In one embodiment, a discharge valve and a two-position ball valve are provided on the pipeline connecting the vacuum rake dryer and the discharge port of the boiling fluidized bed. The discharge valve is close to the boiling fluidized bed, and the two-position ball valve is close to the vacuum rake dryer.
[0011] In one embodiment, a cooler is further provided, which is connected to the top of the vacuum rake dryer, and a vacuum system is provided in the cooler. A circulating water inlet is provided on one side of the cooler, a circulating water outlet is provided on the other side of the cooler, and a wastewater outlet is provided at the bottom of the cooler; circulating water enters from the circulating water inlet and is then output from the circulating water outlet, thereby cooling the exhaust gas discharged from the vacuum rake dryer through the cooler and then discharged by the vacuum system; the vacuum system is of the type of water ring vacuum pump + Roots vacuum pump; the cooler is any one of shell and tube type, plate type, and fin type.
[0012] In one embodiment, the vacuum rake dryer is further provided with a jacket, a shaft tube, a heat transfer oil inlet, a heat transfer oil outlet, and an arc top valve; the heat transfer oil is input from the heat transfer oil inlet into the jacket and the shaft tube, and then input from the heat transfer oil outlet, thereby heating and drying the material in the vacuum rake dryer; the arc top valve is provided at the discharge port of the vacuum rake dryer; the shaft end seal of the vacuum rake dryer adopts a two-stage combined shaft end seal structure of a packing seal and a mechanical seal.
[0013] The present invention also provides a polyamide intermittent deep drying method, which comprises the following steps:
[0014] (1) Turn on the circulating fan, control the gas temperature to 25-30°C after cooling by the surface cooler, control the gas temperature to 180-240°C after heating by the heater, turn on the thermal oil coil in the boiling fluidized bed, and control the temperature of the thermal oil coil to 180-240°C;
[0015] (2) Add the wet material and magnetic balls into the boiling fluidized bed, and let the wet material stay in the boiling fluidized bed for 1-1.5 hours;
[0016] (3) Open the discharge valve and the two-position ball valve, and the material enters the vacuum rake dryer. Turn on the vacuum rake dryer and the vacuum system, control the negative pressure, and the material stays in the vacuum rake dryer for 1-1.5 hours;
[0017] (4) Open the arc top valve to discharge the material and obtain deeply dried polyamide.
[0018] Compared with the prior art, the present invention has at least the following advantages:
[0019] 1. The present invention's bubbling fluidized bed boasts advantages such as low energy consumption and zero dust spillage. It integrates the functions of a thermal oil coil, a fluidized bed, and a bag filter into a single bubbling fluidized bed. The thermal oil coil provides 50-60% of the calorific value, while maintaining low hot air volume and minimizing energy loss. Dust generated during the drying process remains in the bubbling fluidized bed, resulting in a favorable system environment.
[0020] 2. In the polyamide intermittent deep drying system of the present invention, the constant speed section and the speed reduction section of the polyamide deep drying process are controlled separately, the residence time is prolonged, and the speed reduction section adopts a vacuum drying method, which increases the drying speed and reduces the drying gas phase equilibrium pressure.
[0021] 3. In the polyamide intermittent deep drying system of the present invention, polyamide powder is dried more evenly and thoroughly under the fluidization effect of magnetic balls in a boiling fluidized bed, and material agglomeration is avoided.
[0022] 4. The polyamide intermittent deep drying system of the present invention adopts a normal pressure + negative pressure operation mode, which has the advantages of simple operation, high degree of automation, and controllable product quality. The present invention can be widely promoted and applied to the deep drying of materials such as resin, nylon, and polyamide, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0024] Figure 1 This is a schematic structural diagram of a polyamide intermittent deep drying system according to an embodiment of the present invention.
[0025] Among them, the reference numerals are: boiling fluidized bed 1; surface cooler 2; dehumidifier 3; circulating fan 4; heater 5; discharge valve 6; magnetic ball discharge valve 7; two-position ball valve 8; vacuum rake dryer 9; cooler 10 and arc top valve 11. DETAILED DESCRIPTION
[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.
[0027] The object of the present invention is to provide a polyamide intermittent deep drying system and method.
[0028] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.
[0029] Figure 1The diagram is a schematic structural diagram of a polyamide intermittent deep drying system according to one embodiment of the present invention. The polyamide intermittent deep drying system comprises a fluidized bed 1, a surface cooler 2, a dehumidifier 3, a heater 5, and a vacuum rake dryer 9. The surface cooler 2 is connected to the top of the fluidized bed 1, the dehumidifier 3 is connected to the surface cooler 2, one end of the heater 5 is connected to the dehumidifier 3, and the other end of the heater 5 is connected to the fluidized bed 1. The gas discharged from the fluidized bed 1 is treated by the surface cooler 2 and the dehumidifier 3 before entering the heater 5 for heating. The heated gas is then fed from the bottom of the fluidized bed 1 for recycling. The vacuum rake dryer 9 is connected to the discharge port of the fluidized bed 1.
[0030] Preferably, a wet material inlet and a magnetic ball inlet are provided at the top of the fluidized bed 1. Magnetic balls are also added to the fluidized bed 1 and enter the fluidized bed 1 through the magnetic ball inlet. The fluidization of the magnetic balls allows the wet material to be dried more evenly and thoroughly, and can prevent material agglomeration.
[0031] Preferably, a circulating cooling water outlet is provided at the top of the surface cooler 2, and a circulating cooling water inlet is provided at the bottom of the surface cooler 2; the circulating cooling water is input from the bottom of the surface cooler 2 and output from the top of the surface cooler 2, thereby cooling the gas discharged from the boiling fluidized bed 1; the surface cooler 2 is any one of a shell and tube type, a plate type, and a fin type.
[0032] Preferably, a circulating fan 4 is further provided between the heater 5 and the water eliminator 3 .
[0033] Preferably, a heat transfer oil outlet is provided at the top of the heater 5 and a heat transfer oil outlet is provided at the bottom of the heater 5; the heat transfer oil is input from the bottom of the heater 5 and output from the top of the heater 5, thereby heating the gas.
[0034] Preferably, the boiling fluidized bed 1 is a containerized special boiling fluidized bed, which is also provided with a thermal oil coil and a bag dust collector; the thermal oil coil is provided with thermal oil for heating and drying the wet material in the boiling fluidized bed 1; a magnetic ball outlet and a magnetic ball discharge valve 7 are also provided on one side of the boiling fluidized bed 1.
[0035] Preferably, a discharge valve 6 and a two-position ball valve 8 are provided on the pipeline connecting the vacuum rake dryer 9 and the discharge port of the boiling fluidized bed 1 , wherein the discharge valve 6 is close to the boiling fluidized bed 1 and the two-position ball valve 8 is close to the vacuum rake dryer 9 .
[0036] Preferably, a cooler 10 is further provided, which is connected to the top of the vacuum rake dryer 9. A vacuum system is provided in the cooler 10. A circulating water inlet is provided on one side of the cooler 10, a circulating water outlet is provided on the other side of the cooler 10, and a wastewater outlet is provided at the bottom of the cooler 10; circulating water enters from the circulating water inlet and is then output from the circulating water outlet, so that the exhaust gas discharged from the vacuum rake dryer 9 is cooled through the cooler 10 and then discharged by the vacuum system; the vacuum system is of the type of water ring vacuum pump + Roots vacuum pump; the cooler 10 is any one of shell and tube type, plate type, and fin type.
[0037] Preferably, the vacuum rake dryer 9 is further provided with a jacket, a shaft tube, a heat transfer oil inlet, a heat transfer oil outlet and an arc top valve 11; the heat transfer oil is input into the jacket and the shaft tube from the heat transfer oil inlet and input into the heat transfer oil outlet, thereby heating and drying the material in the vacuum rake dryer 9; the arc top valve 11 is provided at the discharge port of the vacuum rake dryer 9; the shaft end seal of the vacuum rake dryer 9 adopts a two-stage combined shaft end seal structure of a packing seal and a mechanical seal.
[0038] The polyamide intermittent deep drying method of the present invention comprises the following steps:
[0039] (1) Turn on the circulating fan 4, control the gas temperature to 25-30°C after cooling by the surface cooler 2, control the gas temperature to 180-240°C after heating by the heater 5, turn on the thermal oil coil in the boiling fluidized bed 1, and control the temperature of the thermal oil coil to 180-240°C;
[0040] (2) adding the wet material and magnetic balls into the boiling fluidized bed 1, and the wet material stays in the boiling fluidized bed 1 for 1-1.5 hours;
[0041] (3) Open the discharge valve 6 and the two-position ball valve 7, and the material enters the vacuum rake dryer 9. Turn on the vacuum rake dryer 9 and the vacuum system, control the negative pressure to 0.095 MPa, and the material stays in the vacuum rake dryer 9 for 1-1.5 hours;
[0042] (4) Open the arc top valve 11 to discharge the material and obtain deeply dried polyamide.
[0043] The gas at 180-240°C in the boiling fluidized bed 1 is collected at the top and discharged, and is dehumidified by the surface cooler 2 and the dehumidifier 3 in sequence. The temperature of the dehumidified gas drops to 35-40°C, and is pressurized to 5-8kPa by the circulating fan 4. It is then input into the heater 5, which heats the gas to 180-240°C and returns it to the boiling fluidized bed 1 for recycling.
[0044] The wet material is discharged after being dried in the boiling fluidized bed 1 for 1-1.5 hours and transported to the vacuum rake dryer 9. The material is heated to 180-240°C through the jacket and shaft tube of the vacuum rake dryer 9 and then discharged through the discharge port. The tail gas in the vacuum rake dryer 9 is cooled by the cooler 10 and then discharged by the vacuum system of the cooler 10.
[0045] Compared with the prior art, the present invention has at least the following advantages:
[0046] 1. The present invention's bubbling fluidized bed boasts advantages such as low energy consumption and zero dust spillage. It integrates the functions of a thermal oil coil, a fluidized bed, and a bag filter into a single bubbling fluidized bed. The thermal oil coil provides 50-60% of the calorific value, while maintaining low hot air volume and minimizing energy loss. Dust generated during the drying process remains in the bubbling fluidized bed, resulting in a favorable system environment.
[0047] 2. In the polyamide intermittent deep drying system of the present invention, the constant speed section and the speed reduction section of the polyamide deep drying process are controlled separately, the residence time is prolonged, and the speed reduction section adopts a vacuum drying method, which increases the drying speed and reduces the drying gas phase equilibrium pressure.
[0048] 3. In the polyamide intermittent deep drying system of the present invention, polyamide powder is dried more evenly and thoroughly under the fluidization effect of magnetic balls in a boiling fluidized bed, and material agglomeration is avoided.
[0049] 4. The polyamide intermittent deep drying system of the present invention adopts a normal pressure + negative pressure operation mode, which has the advantages of simple operation, high degree of automation, and controllable product quality. The present invention can be widely promoted and applied to the deep drying of materials such as resin, nylon, and polyamide, and has broad application prospects.
[0050] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.
Claims
1. A polyamide intermittent deep drying system, characterized in that: include: A boiling fluidized bed (1), a surface cooler (2), a dewatering device (3), a heater (5) and a vacuum rake dryer (9); the surface cooler (2) is connected to the top of the boiling fluidized bed (1), the dewatering device (3) is connected to the surface cooler (2), one end of the heater (5) is connected to the dewatering device (3), and the other end of the heater (5) is connected to the boiling fluidized bed (1); the vacuum rake dryer (9) is connected to the discharge port of the boiling fluidized bed (1).
2. The polyamide intermittent deep drying system according to claim 1, characterized in that: The top of the boiling fluidized bed (1) is also provided with a wet material inlet and a magnetic ball inlet. Magnetic balls are also added to the boiling fluidized bed (1), and the magnetic balls enter the boiling fluidized bed (1) through the magnetic ball inlet.
3. The polyamide intermittent deep drying system according to claim 1, characterized in that: The top of the surface cooler (2) is provided with a circulating cooling water outlet, and the bottom of the surface cooler (2) is provided with a circulating cooling water inlet; circulating cooling water is input from the bottom of the surface cooler (2) and output from the top of the surface cooler (2) to cool the gas discharged from the boiling fluidized bed (1); the surface cooler (2) is any one of a shell and tube type, a plate type, and a fin type.
4. The polyamide intermittent deep drying system according to claim 1, characterized in that: A circulating fan (4) is also provided between the heater (5) and the dehydrator (3).
5. The polyamide intermittent deep drying system according to claim 1, characterized in that: The top of the heater (5) is provided with a heat transfer oil outlet, and the bottom of the heater (5) is provided with a heat transfer oil outlet; the heat transfer oil is input from the bottom of the heater (5) and output from the top of the heater (5), thereby heating the gas.
6. The polyamide intermittent deep drying system according to claim 1, characterized in that: The boiling fluidized bed (1) is a containerized special boiling fluidized bed, and is further provided with a heat transfer oil coil and a bag dust collector. The heat transfer oil coil is provided with heat transfer oil for heating and drying the wet material in the boiling fluidized bed (1). A magnetic ball outlet and a magnetic ball discharge valve (7) are further provided on one side of the boiling fluidized bed (1).
7. The polyamide intermittent deep drying system according to claim 1, characterized in that: A discharge valve (6) and a two-position ball valve (8) are provided on a pipeline connecting the vacuum rake dryer (9) and the discharge port of the boiling fluidized bed (1), wherein the discharge valve (6) is close to the boiling fluidized bed (1), and the two-position ball valve (8) is close to the vacuum rake dryer (9).
8. The polyamide intermittent deep drying system according to claim 1, characterized in that: A cooler (10) is also provided, the cooler (10) is connected to the top of the vacuum rake dryer (9), a vacuum system is provided in the cooler (10), a circulating water inlet is provided on one side of the cooler (10), a circulating water outlet is provided on the other side of the cooler (10), and a wastewater outlet is provided at the bottom of the cooler (10); circulating water enters from the circulating water inlet and is then output from the circulating water outlet, thereby cooling the exhaust gas discharged from the vacuum rake dryer (9) through the cooler (10) and then discharged by the vacuum system; the vacuum system is of the type of a water ring vacuum pump + a Roots vacuum pump; the cooler (10) is any one of a shell and tube type, a plate type, and a fin type.
9. The polyamide intermittent deep drying system according to claim 1, characterized in that: The vacuum rake dryer (9) is further provided with a jacket, a shaft tube, a heat transfer oil inlet, a heat transfer oil outlet, and an arc top valve (11); the heat transfer oil is input from the heat transfer oil inlet into the jacket and the shaft tube, and is input from the heat transfer oil outlet, thereby heating and drying the material in the vacuum rake dryer (9); the arc top valve (11) is provided at the discharge port of the vacuum rake dryer (9); the shaft end seal of the vacuum rake dryer (9) adopts a two-stage combined shaft end seal structure of a packing seal and a mechanical seal.
10. A polyamide intermittent deep drying method, characterized in that: The following steps are involved: (1) Turn on the circulating fan (4), control the gas temperature to 25-30°C after cooling by the surface cooler (2), control the gas temperature to 180-240°C after heating by the heater (5), turn on the thermal oil coil in the boiling fluidized bed (1), and control the temperature of the thermal oil coil to 180-240°C; (2) adding the wet material and the magnetic balls into the boiling fluidized bed (1), and the wet material stays in the boiling fluidized bed (1) for 1-1.5 hours; (3) Open the discharge valve (6) and the two-position ball valve (7), and the material enters the vacuum rake dryer (9). The vacuum rake dryer (9) and the vacuum system are turned on to control the negative pressure. The material stays in the vacuum rake dryer (9) for 1-1.5 hours. (4) Open the arc top valve (11) to discharge the material and obtain deeply dried polyamide.
Citation Information
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