Fluidized bed drying system

Abstract

The utility model relates to the technical field of vitamin C production, in particular to a fluidized bed drying system. The fluidized bed drying system comprises a vitamin C wet material temporary storage tank, the vitamin C wet material temporary storage tank is connected with a magnetic separator through a pre-drying box, the magnetic separator is connected with a fluidized bed through a vibrating screen, the fluidized bed is connected with a cyclone separator through a heat exchanger, and the cyclone separator is connected with an induced draft fan through a bag-type dust collector. A hot air inlet is formed in the vertical wall of the fluidized bed. According to the system, the vitamin C wet material is preliminarily dried through the pre-drying box coil pipe, the water content of the material is reduced, and the material is more stable in state and easy to uniformly disperse before entering the fluidized bed. Materials can fully and uniformly contact with hot nitrogen in the fluidized bed and are heated consistently, so that the problem of non-uniform drying of products is effectively solved, the stability and the consistency of the product quality are improved, and the competitiveness of the products in the market is enhanced.

Description

Technical Field

[0001] This utility model relates to the field of vitamin C production technology, specifically to a fluidized bed drying system. Background Technology

[0002] Vitamin C, as an important nutritional supplement and antioxidant, has wide applications in many fields such as food, medicine, and cosmetics. In the production process of vitamin C, the drying stage plays a crucial role in product quality.

[0003] Traditional vitamin C drying processes, some employing simple drying equipment and others using fluidized bed drying technology, suffer from numerous problems. Firstly, many processes lack a pre-drying stage, directly feeding the wet material with high moisture content and unstable state into the drying equipment. Due to its high moisture content, the wet material is difficult to disperse evenly upon entering the drying zone, resulting in varying degrees of contact with hot nitrogen during drying, uneven heating, and ultimately, uneven product drying. This unevenly dried product exhibits inconsistent quality, hindering its application and sales in the market.

[0004] On the other hand, the raw materials lack effective impurity screening and removal mechanisms in the early processing stage. A large number of impurities, such as magnetic materials, sand particles, and metal shavings, are mixed into the material. These impurities accumulate gradually inside the fluidized bed as the material enters. Due to the structural characteristics of the fluidized bed, such as the relatively narrow inlet, outlet, and internal pipes, impurities easily accumulate in these areas, leading to equipment blockage. Equipment blockage not only significantly reduces production efficiency and increases maintenance costs, but also can affect product yield and quality stability due to frequent shutdowns. Utility Model Content

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a fluidized bed drying system. This system uses a pre-drying chamber coil to initially dry wet vitamin C materials, reducing their moisture content and making the materials more stable and easily dispersed before entering the fluidized bed. Within the fluidized bed, the materials can fully and uniformly contact hot nitrogen gas, resulting in consistent heating. This effectively solves the problem of uneven drying, improves product quality stability and consistency, and enhances the product's market competitiveness.

[0006] This utility model is achieved using the following technical solution:

[0007] The fluidized bed drying system includes a vitamin C wet material storage tank, which is connected to a magnetic separator via a pre-drying box. The magnetic separator is connected to the fluidized bed via a vibrating screen. The fluidized bed is connected to a cyclone separator via a heat exchanger. The cyclone separator is connected to an induced draft fan via a bag filter. A hot air inlet is provided on the vertical wall of the fluidized bed.

[0008] The fluidized bed drying system further includes an air inlet duct, which is connected to a nitrogen preheater via a backwash filter. The nitrogen preheater is connected to a hot air inlet via a blower.

[0009] The pre-drying chamber is equipped with a pre-drying chamber coil, and the heat exchanger is equipped with a heat exchanger coil. The heat exchanger coil is connected to the pre-drying chamber coil via a heating pipe. This structure enables the recovery and utilization of waste heat, performs preliminary drying of wet materials, reduces the moisture content of the materials, and allows the materials to be more evenly dispersed before entering the fluidized bed, improving the uniformity of subsequent drying and saving energy.

[0010] A screw feeder is provided between the pre-drying box and the magnetic separator, and a spray absorption tower is connected to the induced draft fan.

[0011] The fluidized bed is equipped with a bed plate inside, and an air outlet pipe and a feed inlet are provided above the fluidized bed. The air outlet pipe is connected to a heat exchanger through a pipe, and the feed inlet is connected to a vibrating screen through a pipe.

[0012] The fluidized bed has a cold air inlet and a discharge outlet on its vertical wall. The discharge outlet is located above the bed plate, while the hot air inlet and cold air inlet are both located below the bed plate. The bed plate ensures uniform distribution of the incoming gas, allowing the material to fluidize within the bed. The hot and cold air inlets regulate the temperature inside the bed, ensuring sufficient and uniform contact between the material and hot nitrogen in the fluidized state, achieving efficient drying and solving the problem of uneven product drying.

[0013] The working principle of this utility model is as follows:

[0014] Feeding process: The wet vitamin C material is stored in a temporary storage tank and then conveyed to the pre-drying chamber via a screw feeder. The conveying speed of the screw feeder can be adjusted according to production needs, and is generally controlled at a speed that ensures uniform and stable feeding of the material, preventing feeding too fast or too slow, and ensuring the continuity of the subsequent drying process.

[0015] Pre-drying stage: The pre-drying chamber coils inside utilize the waste heat transferred from the heat exchanger coils through the heating pipes to perform preliminary drying of the material. The temperature inside the pre-drying chamber is typically controlled at 40-50℃, and the drying time is approximately 10-15 minutes. During this process, the moisture content of the material decreases, and its fluidity increases, laying the foundation for subsequent uniform dispersion and drying in the fluidized bed.

[0016] Impurity removal stage: The pre-dried material sequentially enters a magnetic separator and a vibrating screen. The magnetic separator uses magnetic principles to adsorb and remove magnetic impurities from the material; the vibrating screen, based on its set mesh size (typically 0.5-2 mm), filters out other non-magnetic impurities. After processing by these two devices, the impurity content of the material entering the fluidized bed is significantly reduced.

[0017] Fluidized bed drying process: The material, after impurity removal, enters the fluidized bed through the feed inlet. Nitrogen gas, through the inlet pipe, first passes through a backwash filter to remove impurities before entering the nitrogen preheater for heating. The heated nitrogen gas is then delivered into the fluidized bed by a blower through the hot air inlet, with the hot air temperature controlled at 60-80℃. Simultaneously, based on temperature changes within the fluidized bed, an appropriate amount of cold nitrogen is introduced through the cold air inlet to regulate the temperature, stabilizing it at 65-75℃. The material, in a fluidized state, is in full contact with the hot nitrogen gas, and the drying time is 15-25 minutes, until the required moisture content standard for the product is achieved.

[0018] Gas-solid separation and exhaust gas treatment: The dried material is discharged from the outlet. Dust-laden exhaust gas enters a heat exchanger through the outlet pipe, where its heat is recovered and utilized. After the temperature decreases, the gas enters a cyclone separator. The cyclone separator uses centrifugal force to separate most of the dust. The gas then enters a bag filter for further purification, ensuring that the exhaust gas meets environmental standards. Finally, an induced draft fan discharges the purified exhaust gas into the atmosphere. The fan's airflow is adjusted according to the system's gas flow requirements to ensure stable airflow within the system.

[0019] Compared with the prior art, the beneficial effects of this utility model are:

[0020] (1) This device is equipped with a pre-drying chamber, which uses coils to pre-dry the wet vitamin C material, reducing the moisture content of the material and making it more stable and easier to disperse evenly before entering the fluidized bed. The material can fully and evenly contact the hot nitrogen gas in the fluidized bed, and is heated uniformly, thus effectively solving the problem of uneven drying of the product, improving the stability and consistency of product quality, and enhancing the product's competitiveness in the market.

[0021] (2) A magnetic separator and a vibrating screen are installed before the material enters the fluidized bed. The magnetic separator can adsorb and remove magnetic impurities from the material, and the vibrating screen can screen out other impurities such as sand, gravel, and debris, which greatly reduces the impurity content entering the fluidized bed. This reduces the risk of equipment blockage at the source, ensures continuous and stable operation of the equipment, improves production efficiency, and reduces equipment maintenance costs.

[0022] (3) By utilizing heat exchanger coils and pre-drying box coils, and connecting them through heating pipes, waste heat recovery and recycling are achieved. The high-temperature exhaust gas heat generated during the fluidized bed drying process is transferred to the pre-drying box for the initial drying of wet materials, reducing energy consumption and lowering production costs. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of this utility model;

[0024] In the diagram: 1. Vitamin C wet material storage tank; 2. Pre-drying box; 3. Screw feeder; 4. Magnetic separator; 5. Vibrating screen; 6. Fluidized bed; 7. Bed plate; 8. Hot air inlet; 9. Cold air inlet; 10. Feed inlet; 11. Air outlet pipe; 12. Heat exchanger; 13. Cyclone separator; 14. Bag filter; 15. Exhaust fan; 16. Spray absorption tower; 17. Discharge port; 18. Backwash filter; 19. Nitrogen preheater; 20. Blower; 21. Air inlet pipe; 22. Heat exchanger coil; 23. Pre-drying box coil; 24. Heating pipe. Detailed Implementation

[0025] To make the objectives and technical solutions of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings.

[0026] Example 1

[0027] like Figure 1 As shown, the fluidized bed drying system includes a vitamin C wet material storage tank 1, which is connected to a magnetic separator 4 via a pre-drying box 2. The magnetic separator 4 is connected to a fluidized bed 6 via a vibrating screen 5. The fluidized bed 6 is connected to a cyclone separator 13 via a heat exchanger 12. The cyclone separator 13 is connected to an induced draft fan 15 via a bag filter 14. A hot air inlet 8 is provided on the vertical wall of the fluidized bed 6. It also includes an air inlet duct 21, which is connected to a nitrogen preheater 19 via a backwash filter 18. The nitrogen preheater 19 is connected to the hot air inlet 8 via a blower 20. The backwash filter 18 has an automatic backwashing function, which can effectively filter impurities in the nitrogen. This ensures the cleanliness of the nitrogen entering the nitrogen preheater, prevents impurities from entering the system and affecting product quality and equipment operation, and extends the service life of the equipment. The pre-drying chamber 2 is equipped with a pre-drying chamber coil 23, and the heat exchanger 12 is equipped with a heat exchanger coil 22. The heat exchanger coil 22 is connected to the pre-drying chamber coil 23 through a heating pipe 24. The heat exchanger 12 realizes the recovery and utilization of waste heat from the exhaust gas, transferring heat to the pre-drying chamber 2, improving energy utilization and reducing production costs. A screw feeder 3 is provided between the pre-drying chamber 2 and the magnetic separator 4, and a spray absorption tower 16 is connected to the induced draft fan 15. The fluidized bed 6 is equipped with a bed plate 7. An exhaust pipe 11 and a feed inlet 10 are provided above the fluidized bed 6. The exhaust pipe 11 is connected to the heat exchanger 12 through a pipe, and the feed inlet 10 is connected to the vibrating screen 5 through a pipe. The vertical wall of the fluidized bed 6 is equipped with a cold air inlet 9 and a discharge outlet 17. The discharge outlet 17 is located above the bed plate 7, and the hot air inlet 8 and the cold air inlet 9 are both located below the bed plate 7.

[0028] The above-mentioned fluidized bed drying system includes the following steps during operation:

[0029] (1) The wet vitamin C material is stored in the wet vitamin C material storage tank 1 and is conveyed to the pre-drying box 2 by the screw feeder 3. The pre-drying box coil 23 inside the pre-drying box 2 uses the residual heat from the heat exchanger coil 22 through the heating pipe 24 to perform preliminary drying of the material. The temperature inside the pre-drying box 2 is usually controlled at 40-50℃ and the drying time is about 10-15 minutes. (2) The pre-dried material enters the magnetic separator 4 and the vibrating screen 5 in sequence. The magnetic separator 4 uses the magnetic principle to adsorb and remove magnetic impurities in the material; the material after impurity removal enters the fluidized bed 6 through the feed inlet 10. Nitrogen gas enters the air inlet pipe 21, first passes through the backwash filter 18 to remove impurities in the nitrogen gas, and then enters the nitrogen preheater 19 to be heated. The heated nitrogen gas is sent into the fluidized bed 6 by the blower 20 through the hot air inlet 8, and the hot air temperature is controlled at 60-80℃. Meanwhile, according to the temperature change in the fluidized bed 6, an appropriate amount of cold nitrogen is introduced through the cold air inlet 9 to regulate the temperature and stabilize the temperature in the fluidized bed 6 at 65-75℃. (3) The dried material is discharged from the outlet 17. The dust-containing exhaust gas enters the heat exchanger 12 through the exhaust pipe 11. The heat of the exhaust gas is recovered and utilized in the heat exchanger 12. After the temperature is reduced, it enters the cyclone separator 13. The cyclone separator 13 uses centrifugal force to separate most of the dust. Then the gas enters the bag filter 14 for further purification to ensure that the exhaust gas meets environmental protection standards. Finally, the purified exhaust gas is discharged into the atmosphere by the induced draft fan 15. The air volume of the induced draft fan 15 is adjusted according to the gas flow requirements in the system to ensure the airflow stability in the system.

Claims

1. A fluid bed drying system characterized by, The application relates to a vitamin C wet material temporary storage tank (1), which is connected with a magnetic separator (4) through a pre-drying box (2), the magnetic separator (4) is connected with a fluidized bed (6) through a vibrating screen (5), the fluidized bed (6) is connected with a cyclone separator (13) through a heat exchanger (12), the cyclone separator (13) is connected with an induced draft fan (15) through a bag-type dust collector (14), and a hot air inlet (8) is arranged on the vertical wall of the fluidized bed (6).

2. The fluid bed drying system of claim 1, wherein, The application further comprises an air inlet pipeline (21), which is connected with a nitrogen pre-heater (19) through a backwashing filter (18), the nitrogen pre-heater (19) is connected with the hot air inlet (8) through a blower (20).

3. The fluid bed drying system of claim 1, wherein, The pre-drying box (2) is internally provided with pre-drying box coil pipes (23), the heat exchanger (12) is internally provided with heat exchanger coil pipes (22), and the heat exchanger coil pipes (22) are connected with the pre-drying box coil pipes (23) through a temperature-rising pipeline (24).

4. The fluid bed drying system of claim 1, wherein, The pre-drying box (2) is provided with a screw feeder (3) between the pre-drying box (2) and the magnetic separator (4), and the induced draft fan (15) is connected with a spray absorption tower (16).

5. The fluid bed drying system of claim 1, wherein, The fluidized bed (6) is internally provided with a bed plate (7), the upper portion of the fluidized bed (6) is provided with an air outlet pipeline (11) and a feeding inlet (10), the air outlet pipeline (11) is connected with the heat exchanger (12) through a pipeline, and the feeding inlet (10) is connected with the vibrating screen (5) through a pipeline.

6. The fluid bed drying system of claim 5, wherein, The vertical wall of the fluidized bed (6) is provided with a cold air inlet (9) and a discharging outlet (17), the discharging outlet (17) is located above the bed plate (7), and the hot air inlet (8) and the cold air inlet (9) are both located below the bed plate (7).

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