A ring die is a cylindrical wear-part with extrusion channels around its circumference. Rollers press feedstock through the channels by centrifugal force as the die rotates. A flat die is a horizontal disc with vertical channels — generally simpler, lower-throughput, and more common in small/farm-scale machines.
For paddy-straw (parali) operations at industrial scale, the ring die wins on three axes. First, throughput: 1,500–2,000 kg/h sustained, against flat-die outputs typically below 500 kg/h. Second, density consistency: the radial pressure distribution keeps pellet density within ±3% across the run, against ±8% for flat dies under similar feedstock. Third, serviceability: ring dies are field-replaceable as a single unit at ₹1,00,000 per piece (Yulong pattern) with MOQ 5 and same-week dispatch from Sardulgarh.
Flat dies have one advantage: capex is materially lower for a brand-new press, and the wear-replacement cycle is simpler if you're willing to take throughput hits. For 100–300 kg/h operations on a single farm — say, on-site straw management for a 50-acre plot — a flat-die press is sometimes the right tool.
At 1.5 TPH or above, the answer is unambiguous: ring die, properly metallurgied for paddy-straw silica content. The 8th-Generation Centrifugal Pellet Machine is built for exactly this duty cycle.
About the author
D Sharma is the proprietor of Shri Balaji Biomass Solutions, manufacturer of the 8th-Generation Centrifugal Pellet Machine, the complete biomass pellet plant line and a 96-SKU OEM spare-parts catalogue. Based at the Sardulgarh works, Distt. Mansa, Punjab.