ISO 17831-2:2025

Overview

ISO 17831-2:2025 is an international standard developed by ISO that specifies a reliable method for determining the mechanical durability of solid biofuel briquettes. Mechanical durability is a key indicator of the briquettes' resistance to shock and abrasion resulting from handling, transportation, and storage. This durability test ensures that briquettes maintain structural integrity, minimizing fines generation and material losses during logistical operations.

This standard is part two of the ISO 17831 series, dedicated specifically to briquettes, distinguishing them from pellets based on larger dimensions (typically above 25 mm diameter). The document builds on previous editions with updated procedures, equipment specifications, and references aligned with other key biofuel standards.

Key Topics

• Scope and Purpose: The standard defines a test method to quantify the mechanical durability of compressed biomass briquettes. Durability reflects briquette quality related to their resistance to breakage under mechanical stresses during transport and handling.

• Test Principle: Samples of briquettes are rotated inside a cylindrical steel drum (durabilimeter), where they collide and rub against each other and drum walls. After a specified number of rotations at a controlled speed (21 rpm for 5 minutes), the sample is sieved to separate broken particles. The mechanical durability is calculated as the mass percentage of intact briquettes remaining.

• Equipment Specifications:

  • Durabilimeter drum: Cylindrical steel drum with 600 mm diameter and length, featuring an internal deflector.
  • Sieve (Sieve circle): Circular sieve with 5.6 mm diameter round holes for manual sieving, complying with ISO 3310-2.
  • Balance: Precision balance with at least 0.1 g accuracy and 2 kg capacity to weigh samples precisely.
  • Additional accessories include a dust-tight cover for the drum and sample preparation tools.

• Sample Preparation:

  • Samples must be representative and meet size and weight requirements based on briquette type (A, B, or C).
  • Moisture content must be measured as it influences mechanical durability, following ISO 18134 methods.
  • Samples are conditioned to ambient temperature and stored airtight before testing.

• Test Procedure:

  • Select and weigh test samples as per classification.
  • Rotate samples inside the durabilimeter at 21±0.1 rpm for 5 minutes.
  • Sieve the contents manually to remove fines and broken particles.
  • Calculate the mechanical durability based on the weight ratio of remaining briquettes.

• Reporting:

  • The test report must include moisture content, sample description, appearance of briquettes before and after testing, test parameters, and calculated durability results.

Applications

ISO 17831-2:2025 is essential for producers, suppliers, and users of solid biofuel briquettes aiming to:

• Ensure Quality Control: Implementing this standardized durability test enables manufacturers to assess and improve briquette quality, reducing fines production and waste.

• Optimize Handling and Transportation: Durable briquettes withstand mechanical stresses during transport, minimizing losses and contamination, thus maintaining energy density and combustion efficiency.

• Support Compliance and Certification: This standard aligns with broader biomass fuel quality standards like ISO 17225, helping stakeholders comply with national and international regulations and market requirements.

• Research and Development: Provides a benchmark method to evaluate the effects of raw materials, binders, and production techniques on briquette mechanical performance.

Related Standards

ISO 17831-2:2025 works in conjunction with a series of standards dedicated to solid biofuels and testing methods:

• ISO 17831-1 - Determination of mechanical durability of pellets (Part 1: Pellets)
• ISO 17225-1 - Solid biofuels - Fuel specifications and classes (General requirements)
• ISO 3310-2 - Test sieves - Technical requirements (Perforated metal sheets)
• ISO 5370 - Determination of fines content in pellets
• ISO 18134-1 & ISO 18134-2 - Moisture content determination methods
• ISO 14780 - Sample preparation for solid biofuels
• ISO 18135, ISO 21945 - Sampling procedures for solid biofuels

These complementary standards ensure a comprehensive framework for assessing biomass fuel quality and consistency.

Keywords: ISO 17831-2, mechanical durability, biofuel briquettes, solid biofuels, briquette testing, durability test method, bioenergy quality standards, mechanical resistance, briquette quality control, biomass fuel handling