The boiling granulation dryer, as a core equipment in the pharmaceutical, food, and chemical industries, achieves integrated operation of material mixing, granulation, and drying through fluidized bed technology. The precision of its operation directly affects the uniformity of particles, moisture content, and yield of finished products. This article systematically outlines the standardized operation process and key control points from four stages: equipment preparation, parameter setting, operation monitoring, to shutdown maintenance.

　　1、 Preparation before operation: Building a solid foundation of safety and efficiency

1. Equipment inspection

Confirm that the spray system (spray gun, pump, pipe) is not blocked, and the nozzle aperture matches the material characteristics (for viscous materials, anti blocking nozzles are required).

Check the integrity of the filter bag using the pressure difference method: start the induced draft fan to increase the pressure difference in the bag chamber to 800-1200Pa, and observe whether the pressure drop is stable for 10 minutes.

Verify the accuracy of the temperature sensor and pressure gauge to ensure an error range of ≤± 1%.

2. Material pretreatment

Powder materials need to pass through an 80-120 mesh sieve, with a controlled particle size distribution D90 ≤ 150 μ m.

When the moisture content exceeds the standard (such as>8%), flash drying or fluidized bed pre drying should be carried out in advance.

The viscosity of liquid adhesive shall be controlled at 50-500mPa · s to avoid spray splashing.

　　2、 Operating parameter settings: precise adjustment and control of particle quality

1. Flow state optimization

Initial intake temperature setting: Heat sensitive materials (such as antibiotics) ≤ 60 ℃, ordinary materials 80-100 ℃.

Adjust the air intake through the observation window to make the material in a "boiling cloud" state, with a fluctuation range of bed pressure difference within ± 50Pa.

2. spray granulation control

Spray gun position: 20-30cm away from the material surface, spray angle 45 ° -60 °.

Atomization pressure: Centrifugal spray disc speed 8000-12000rpm, pressure nozzle pressure 0.2-0.4MPa.

Liquid supply rate: In the initial stage, spray 3% -5% of the material amount, and gradually increase to 8% -12% after the particles are formed.

3. Determination of drying endpoint

The outlet exhaust gas temperature remains stable at the set value ± 2 ℃ for 15 minutes.

Sample and test the moisture content of particles (using a rapid moisture analyzer), and stop heating after reaching the target value (such as 2% -5%).

　　3、 Operation monitoring and exception handling

1. Real time monitoring of key parameters

Bed temperature: Record every 30 minutes, and adjust the air intake if the fluctuation exceeds ± 5 ℃.

Filter bag pressure difference: When it exceeds 2500Pa, start the blowback system, with a blowback time of 0.1-0.2 seconds and a frequency of 15-20 times per minute.

2. Emergency plan for common faults

Agglomeration: Immediately reduce the liquid supply rate to 50% and increase the air intake by 10% -15%.

Nozzle blockage: Switch to the backup spray gun and clean the blocked nozzle with acetone (to be operated after shutdown).

Filter bag damage: Start the spare bag room, maintain stable negative pressure in the system, and replace the filter bag after shutdown.

　　4、 Shutdown and Maintenance: The Key to Extending Equipment Lifespan

1. Standardized shutdown process

After turning off the heating system, continue to supply air for 10-15 minutes to cool the equipment.

When the bed temperature drops below 40 ℃, turn off the induced draft fan and spray system.

Clean up the residual materials in the fluidized bed and blow back the filter bag with compressed air until there is no dust residue.

2. Preventive maintenance plan

Check the wear of the spray gun seal ring every week, with a replacement cycle of ≤ 3 months.

Clean the fins of the heat exchanger monthly to prevent dust accumulation from affecting heat transfer efficiency.

Conduct fluidized bed airflow distribution testing every quarter to ensure a uniformity coefficient of ≥ 0.8.

Practical value: By strictly implementing this operating standard, a pharmaceutical company has reduced the standard deviation of particle size distribution (D10/D50/D90) of ibuprofen granules by 40%, shortened drying time by 25%, and reduced equipment failure rate by 60%. From experiential operation to precise control, standardized processes are the core path to improving the operational efficiency of boiling granulation dryers.