Investigating screw-agitator speed ratio impact on feeding performance in pharmaceutical manufacturing using discrete...

Area of Science:

• Chemical Engineering
• Materials Science
• Process Engineering

Background:

• Continuous powder handling demands precise and consistent feeding for final product quality.
• Agitator-induced intermixing significantly impacts powder properties like bulk density and flow patterns, yet is often overlooked.
• Understanding these effects is critical for optimizing powder feeding processes.

Purpose of the Study:

• To develop a Digital Twin (DT) framework combining discrete element method (DEM) modeling and experimental data for continuous powder feeding.
• To quantitatively predict powder flow behavior, including feed factor and accumulation zones.
• To identify optimal operating ranges for screw-agitator ratio and screw speed, considering powder cohesivity.

Main Methods:

• Utilized discrete element method (DEM) modeling to simulate powder flow dynamics within a commercial-scale feeder.
• Integrated DEM simulations with experimental data to create a validated Digital Twin (DT) framework.
• Conducted scenario analysis to evaluate the impact of screw-agitator ratio and screw speed on powder flow.

Main Results:

• The DEM model accurately captured key flow features like bypass trajectories, stagnant zones, and preferential flow patterns.
• Quantitative predictions for feed factor and material accumulation zones were achieved.
• Identified that powders with poor flow characteristics necessitate tighter operational constraints and a carefully selected screw-agitator ratio.

Conclusions:

• The proposed Digital Twin (DT) framework effectively models and predicts powder flow behavior in continuous feeders.
• Selecting an appropriate screw-agitator ratio, rather than a fixed value, is crucial for optimizing powder flow.
• Achieving an optimal operation window with minimal agitation ensures unhindered flow and reduces mass flow rate variability.