Comparison of granulation processes between rotary drum granulator and flat die granulator

Rotary drum granulators and flat die granulators are the two main types of equipment for organic fertilizer production, and they work very differently:

Drum Granulator: Uses a rotating, tilted drum. Material rolls and forms balls under centrifugal force. This is classic "wet granulation".

Flat Die Granulator: Uses rollers pressing vertically against a flat die to force material through holes. This is a "dry granulation" technique.

1.Particle Characteristics

Drum Granulation:Makes spherical pellets with a smooth surface but lower density. Good for slow-release fertilizers.

Flat Die Granulation: Makes cylindrical pellets that are very dense. Better suited for mechanical application.

2.Material Compatibility

Drum Granulation: Needs 20%-30% liquid (water or binder). Best for sticky materials like livestock manure or humic acid.

Flat Die Granulation: Can handle dry powders with moisture <15%. Works better with fibrous stuff like straw powder or mushroom residue.

3.Production Efficiency

Drum Granulation: Output is 5-20 tons/hour per machine. But you need drying equipment too, so overall energy use is higher.

Flat Die Granulation: Output is 3-15 tons/hour. Makes finished pellets directly, cutting electricity use by 30%-40%.

4.Process Control

Drum Granulation: Needs careful adjustment of the drum angle (35-55 degrees), speed (15-25 rpm), and liquid spray.

Flat Die Granulation: Key controls are the roller gap (0.1-0.3mm) and die thickness. Generally simpler to operate.

5. Yield and Maintenance

Drum Granulation: Yield is 85%-92%. The drum can get material buildup and needs regular cleaning.

Flat Die Granulation: Yield can reach 95%. Replacing worn dies can be costly.

In short, both drum and flat die granulators have their own strengths. Fertilizer producers need to pick the right machine based on their specific needs to balance efficiency and quality.