Overview - ISO 18847:2024 (Solid biofuels - Particle density of pellets and briquettes)
ISO 18847:2024 specifies a standardized laboratory method to determine the particle density of compressed solid biofuels (pellets and briquettes). The standard defines the measurement principle, required reagents and apparatus, sample preparation and test procedures so comparative determinations can be made across laboratories. The reference (buoyancy) method measures both mass and volume using liquid buoyancy; informative alternatives for briquettes (stereometric estimation) and for on‑site pellet checks (liquid displacement) are provided in annexes.
Key technical topics and requirements
- Measurement principle: Buoyancy - apparent loss in weight between measurements in air and submerged in liquid yields displaced volume; particle density = mass / volume.
- Reagents and environment:
- Water with conductivity < 1 000 µS/cm, temperature 10 °C–30 °C.
- Non‑ionic surfactant detergent (e.g., Triton® X‑100) as wetting agent; if an alternative is used, its density must be determined and used in calculations.
- Paraffin (melting point 52–54 °C) referenced in apparatus preparation.
- Apparatus:
- Pellets: balance readable to 0.001 g, ~200 ml glass beaker, density determination rig with bridge and perforated submergence dish (holds ≥4 pellets).
- Briquettes: balance readable to 0.01 g (0.1 g for >500 g briquettes), transparent container large enough to avoid liquid level errors, non‑absorbent steel string and hanging support, removable weight for low‑density materials.
- Sample preparation & sizes:
- Laboratory sample according to ISO 18135 / ISO 21945 and test portion per ISO 14780.
- Typical test-sample masses: 500 g (pellets ≤12 mm), 1 000 g (pellets >12 mm), or minimum 15 briquettes.
- Test portion selected: minimum 40 pellets or 10 briquettes - stored sealed to retain moisture.
- Procedure details:
- Buoyancy readings are time‑sensitive (pellets disintegrate in water); readings fixed at 5 s to improve reproducibility.
- Performance characteristics (repeatability and reproducibility) and test report content are specified.
Practical applications and users
- Useful for manufacturers, quality control labs, research institutes and certification bodies involved in solid biofuels, especially:
- Pellet and briquette producers verifying compaction and handling properties.
- Fuel testing laboratories determining material suitability for storage, transport and combustion.
- Appliance/boiler manufacturers assessing fuel feed and combustion behavior related to particle density.
- Results inform decisions on storage volume, abrasion resistance, fragmentation risk, feed system performance and thermal behavior.
Related standards and keywords
- Normative references: ISO 14780, ISO 16559, ISO 18135, ISO 21945.
- SEO keywords: ISO 18847:2024, particle density, solid biofuels, pellets, briquettes, buoyancy method, liquid displacement, stereometric estimation, sample preparation, fuel testing.
