Comparison of granulation processes between double roller press granulator and flat die granulator

In fertilizer, feed, and chemical granulation, double roller press granulators and flat die granulators are the two most common types of equipment. They differ in working principles, suitable applications, and finished product characteristics.

1.Working Principle Comparison

Double Roller Press Granulator: Uses two counter-rotating rollers. It forces materials through die holes under high pressure to form granules. This is a dry granulation process, requiring no extra water or binders.

Flat Die Granulator: Relies on the rolling action of vertical press wheels against a flat die. Materials are squeezed through die holes on the die surface, often needing some added moisture or binders to help form properly.

2.Material Suitability Differences

Double Roller Press Granulator: Especially good for harder materials like inorganic salts. It requires low raw material moisture content (typically 3-8%).

Flat Die Granulator: Better suited for materials high in organic content, like organic fertilizers. Raw material moisture usually needs to be 15-25% to ensure good shaping.

3.Finished Pellet Characteristics

Double Roller Press Granulator: Produces high-density, high-strength pellets. The surface is rougher, and shape regularity is moderate. Pellet size is uniform, achieving a high yield of over 95%.

Flat Die Granulator: Produces smoother surfaced pellets with a neater, more regular shape. However, pellet strength is relatively lower, and powder generation is more likely.

4.Maintenance and Operating Costs

Double Roller Press Granulator: Dies need replacing less often, maintenance is simpler, and operation is stable. Initial investment cost is higher.

Flat Die Granulator: Dies wear out faster, requiring more frequent adjustment of the press wheel gap. Equipment cost is generally lower.

Choosing between a double roller press granulator and a flat die granulator mainly depends on the raw material properties, production capacity, and finished product requirements.