Overview

BZLG series nitrogen closed-loop vibration fluidized bed drying unitIt is a drying and cooling equipment that can operate continuously, widely used for drying, cooling, and other operations of powder and fine granular materials in industries such as chemical, pharmaceutical, and food. It is particularly suitable for handling flammable and explosive powder and fine granular materials.

working principle

This system consists of vacuum feeding, heater, drying host, condenser, cyclone dust collector, fan, absorption tower, and nitrogen system. The entire drying process is carried out in a sealed environment under nitrogen protection, and the discharge is carried out in a sealed environment, which has the characteristics of no dust and high safety.

Before using the system, use nitrogen to replace the air inside the system, so that the oxygen content in the system reaches the safe concentration of the solvent. Wet materials enter the drying machine through the feeding port on the equipment in a sealed container. The air supply fan sends filtered nitrogen gas, which is heated by a heater to the temperature required for the drying process. It then enters the boiling bed to perform heat and mass transfer (drying) on the material added through the differential feeding port. After the feeding is completed, it is dried to the desired final humidity of the material. During the drying process, the humid and hot gas carries a small amount of micro powder and passes through the dust collector to separate all the micro powder into gas-solid in the dust collector. Solid dust is collected in the dust collector and returned to the dryer. The gas enters the multi-stage condenser to condense the solvent in the humid and hot gas. The condensed solvent is collected in a collection tank and stored (zero emission to air, recyclable). After condensation and dehumidification, the dry nitrogen gas is then sent to the heater for circulation through a blower.

Nitrogen filling and oxygen removal process: Close the corresponding pipeline electric valve, turn on the exhaust fan, extract air for a certain period of time, when the system pressure gauge displays a certain value, close the corresponding electric valve, close the exhaust fan, open the nitrogen flushing electric valve, and fill the system with nitrogen; When the residual oxygen level in the online oxygen detection device measurement system is less than the required value, the program controller PLC sends an instruction to close the nitrogen flushing electric valve, and the nitrogen filling process of the system is completed. Enter the next process.

Drying process: Turn on the circulating blower, turn on the radiator to heat the system temperature to the required temperature; Turn on the feed and discharge fans with stepless frequency conversion speed regulation, and start the drying process; The hot air exchanges heat with the materials in the fluidized bed, and the tail gas is discharged from the outlet of the horizontal boiling fluidized bed. After passing through the condenser and demister, it is cooled and dehydrated before entering the circulating blower for drying cycle. After a certain period of drying, the finished products that meet the final moisture requirements of the product are discharged from the dryer for collection, completing the drying process.

Solvent condensation recovery process: The drying circulating air passes through the circulating air duct, condenses in the condenser, and is collected by the solvent recovery system through the water remover. After removing the moisture from the circulating air, it enters the drying machine again to complete the solvent recovery process.

System nitrogen protection: Nitrogen protection is mainly controlled by the brake of the line oxygen detection instrument. When the oxygen content exceeds the standard, the nitrogen filling pneumatic valve is automatically opened to fill the drying system with nitrogen. When the residual oxygen level in the system is below the required value, the nitrogen filling pneumatic valve is automatically closed to ensure the safe operation of the system.

System Overpressure Protection: When the system pressure exceeds the set value, the pressure detection device will activate, open the exhaust pneumatic valve, and the exhaust fan will operate automatically. When the system pressure meets the requirements, the pressure detection device will reset and automatically close the exhaust pneumatic valve and exhaust fan, and the system will operate normally.

Features of the equipment

• After being dried by this system, the hot and humid gases containing solvents enter the condenser to condense the solvents in the gas (with a solvent recovery rate of over 95%), which can both recover the solvents and condense the dehumidified dry gas. The recovered solvent can be recycled again, which can save costs and will not cause environmental pollution due to exhaust emissions. The hot and humid gas undergoes condensation dehumidification, resulting in a lower absolute humidity inside the gas (compared to ordinary fluidized bed drying) and stronger drying ability. It is more suitable for moisture absorbing materials that are affected by humidity environments and is suitable for drying or cooling flammable and explosive materials such as MBS.
• 2. This system is a fully enclosed structure, and the equipment is filled with inert gas (such as nitrogen) inside. When drying anaerobic materials or materials containing flammable and explosive solvents, there is no oxygen in the gas, making it impossible to burn or oxidize. This can effectively prevent equipment from catching fire or exploding during production, making it safer than ordinary equipment.
• 3. When the system is working, the unique air separation design reduces the clumping phenomenon of the product, ensures the boiling height, and makes the contact between the hot air and the coarse and fine particles more complete, resulting in a faster drying rate.
• 4. This system achieves discharge under fully enclosed conditions, greatly reducing the labor intensity of workers and ensuring that there is no dust in the workshop. The workshop environment is good and the degree of automation is high.
• 5. The fluidized heat transfer is uniform, without overheating or dead corners, and the product quality is good.
• 6. Adjustable weir plate design for export, adjustable material layer thickness to increase production.
• 7. This system has a high degree of automation and is easy to disassemble, clean, and maintain.