Biomass Pelletiser – Ring Die Type: BIS Draft Specification and Test Code
BIS Information
The Bureau of Indian Standards (BIS) has developed a draft standard for biomass pelletisers (ring die type) under FAD 20: Agriculture and Food Processing Equipment Sectional Committee.
Document: FAD 20 (27728) WC – August 2025
Title: Biomass Pelletiser – Ring Die Type – Specification and Test Code
Scope: Covers materials, construction, performance, testing, and marking requirements.
Context: Part of India’s mission to promote renewable biomass energy (SAMARTH program).
Key Point Summary
Promotes biomass pelletisation for reducing coal use in power plants.
Defines material specifications for critical components (die, rollers, shaft, gearbox).
Covers vertical and horizontal ring die pelletiser types.
Performance requirements: efficiency ≥ 85%, fines ≤ 5%, durability ≥ 95%, bulk density ≥ 600 kg/m³.
Specifies test methods: no-load, load, durability, calorific value, hardness, etc.
BIS certification marking and safe packing guidelines included.
Scope
This standard applies to ring die biomass pelletisers, prescribing:
Materials and construction standards.
Performance requirements.
Test methods for evaluation.
Safety and operational guidelines.
Terminology
Feed Mechanism: Ensures uniform feeding and regulates rate.
Pelletiser: Equipment that compresses biomass into pellets.
Mechanical Durability: Ability of pellets to resist shocks/friction during handling.
Pelletiser Types
Vertical Ring Die Pellet Mill: Static die in horizontal plane, rollers rotate vertically; gravity-assisted flow improves efficiency.
Horizontal Ring Die Pellet Mill: Rotating die in vertical plane, rollers rotate horizontally; uses auger feeding system for uniform compression.
Material Specification for Various Components
Component
Material/Grade
BIS Reference
Compression roller
20CrMnTi
IS 3077
Die cover
SS 202 / SS 304
IS 6911
Feed hopper
SS 202 / SS 304
IS 6911
Gear
20CrMnTi / 20MnCr5
IS 3077
Gearbox
Cast iron FG260
IS 210
Main housing (bearing)
EN8 / Mild Steel
IS 2062
Main shaft
EN8
—
Cutting blade
SS 440 / SS 410
IS 6911
Ring die
20CrMnTi / X46Cr13
—
Feeding System
Must ensure uniform material flow.
Designed to handle various biomass types.
Integrated auger or screw conveyor mechanism.
Ring Die
Hardness: 50–60 HRC (Rockwell scale).
Die holes: uniform shape and spacing.
Case hardened for wear resistance
Compression Rollers
Case hardened.
Hardness: 50–60 HRC.
Must endure high compressive forces.
Cooling System
Equipped with oil cooling (air cooler, radiator, etc.).
Oil temperature must remain below 90°C.
Testing with Example
No-load Test: Run 30 minutes × 4 times; record power consumption.
Load Test: Run for 20 hours with rated capacity.
Input material: ≤ 3.15 mm, 8–14% moisture.
Monitor shaft speed, energy meter, pellet size, density, calorific value.
Hardness: Tested using Texture Profile Analysis (TPA) at 0.2 mm/s with 500 kg load cell.
Hardness of Pellets
Determined by compression until fracture.
Average from 20 pellets per test run.
Reported in Newton (N).
Specification Key Points
Efficiency: ≥ 85%
Fines Content: ≤ 5%
Pellet Density: ≥ 1100 kg/m³
Bulk Density: ≥ 600 kg/m³
Durability: ≥ 95% mass
Pellet Size: Diameter 6–20 mm
Calorific Value: Determined as per IS 17654.
Summary Report
Manufacturer’s details.
Power consumption at load/no-load.
Pellet size, density, calorific value.
Efficiency, durability, fines content.
Breakdown and maintenance records.
Conclusion
The BIS draft standard ensures safe, efficient, and durable ring die pelletiser design. It supports India’s clean energy mission, reduces coal dependency, and provides a framework for quality biomass pellet production.
This document is prepared from the BIS draft standard (FAD 20:27728, August 2025) and is for reference and informational purposes only. It should not be used as an official Indian Standard without BIS approval.
