ISO 17831-1:2015

Overview

ISO 17831-1:2015 - Solid biofuels - Determination of mechanical durability of pellets - Part 1: Pellets - specifies a laboratory method to measure the mechanical durability of solid biofuel pellets. Mechanical durability quantifies a pellet’s resistance to shocks and abrasion incurred during handling, storage and transportation. The standard is intended for producers, testing laboratories, equipment manufacturers and purchasers who need reliable durability data for quality control, specification and process design.

Key topics and technical requirements

• Scope and purpose: Defines the test objective, terminology and reporting requirements for pellet durability testing.
• Apparatus (pellet tester):
  • Dust-tight stainless-steel rotating box (inner dims ≈ 300 × 300 × 125 mm, wall thickness ~1.5 mm).
  • A baffle fixed on the diagonal, rounded edges to avoid cutting.
  • Rotation at (50 ± 2) rpm; sample subjected to controlled pellet-to-pellet and pellet-to-wall collisions.
• Sieve and balance:
  • Manual sieve with round holes of 3.15 mm diameter (recommended ≥ 400 mm diameter).
  • Balance capacity ≥ 2 kg with 0.1 g readability.
• Sample preparation:
  • Sampling and sub-sampling per the referenced sampling/sample-preparation documents.
  • Minimum sample size 2.5 kg; pre-sieve to remove fines < 3.15 mm.
  • Moisture content determination according to ISO 18134 (oven-dry methods).
• Procedure:
  • Duplicate determinations.
  • Test portion: (500 ± 10) g (500 ± 50 g for pellets >12 mm).
  • Tumble for 500 rotations at 50 rpm, then gently sieve (5–10 circular shakes) to separate fines.
• Calculation:
  • Mechanical durability (DU) = (mass after tumbling / mass before tumbling) × 100; results to two decimals, report rounded to 0.1%.
• Precision and bias:
  • For DU ≥ 97.5%: repeatability 0.3% abs, reproducibility 0.6% abs.
  • For DU < 97.5%: repeatability 2% abs, reproducibility 3% abs.
• Test report: Lab ID, sample ID, reference to ISO 17831-1, mean DU (as received), moisture content, pre-test fines %, and any deviations.

Practical applications and users

• Pellet manufacturers: production control and product specification.
• Quality laboratories: routine and comparative testing for compliance and research.
• Equipment designers and plant engineers: evaluating handling systems and transport resilience.
• Buyers and specifiers: procurement acceptance criteria and performance comparison.
• Logistics and storage managers: assessing breakage risk during distribution.

Related standards

• ISO 17831-2 (Part 2: briquettes) - complementary method for briquettes.
• Referenced documents: ISO 16559 (terminology), ISO 18134-1/2 (moisture determination), ISO 3310-2 (test sieves) and ISO DIS 18846 (fines content). Draft sampling/sample-preparation documents referenced for correct sample handling.

Keywords: ISO 17831-1, mechanical durability, pellets, pellet tester, solid biofuels, durability testing, 3.15 mm sieve, tumbling test, pellet quality.