Overview
ISO 23343-1:2021 - Solid biofuels: Determination of water sorption and its effect on durability of thermally treated biomass fuels - Part 1: Pellets specifies a laboratory method to measure water sorption and the resulting change in mechanical durability of thermally treated biomass pellets after immersion in water. The standard defines how to quantify post‑immersion durability reduction (the difference between as‑received durability and durability after wetting) and provides a repeatable test procedure for comparative assessment of pellet resistance to moisture.
Keywords: ISO 23343-1:2021, solid biofuels, water sorption, thermally treated biomass, pellets, durability, moisture content, post-immersion durability reduction
Key Topics and Requirements
- Scope and purpose: Laboratory determination of water uptake (sorption) and its effect on pellet durability; intended for thermally treated compressed biomass pellets (not briquettes).
- Sampling and sample size: Minimum laboratory sample 5.0 kg; division into four equal sub‑samples per ISO 14780 and ISO 18135 guidance.
- Apparatus and sieving:
- Test sieve with 3.15 mm round holes (ISO 3310-2); immersion containers with 1.0 mm wire mesh recommended.
- Balance with 0.1 g readability; drying oven ≤ 40 °C; flat drying trays with specified surface loading.
- Test procedure (high level):
- Determine as‑received moisture (ISO 18134‑1/2) and mechanical durability (ISO 17831‑1).
- Remove fines (ISO 18846), immerse two sieved sub‑samples (1 000 g ± 10 g each) in purified water at 23 ± 5 °C for 24 h ± 0.25 h.
- Drain, equilibrate, measure post‑immersion moisture and durability; calculate water sorption (Sw) and post‑immersion durability reduction (DURpi).
- Data and reporting: Includes calculations, performance characteristics and required test report content to support traceability and comparison.
Applications and Users
Practical applications of ISO 23343-1:2021 include:
- Quality control and acceptance testing by pellet manufacturers and testing laboratories
- Product classification for handling and outdoor storage suitability
- Procurement and specifications for power plants, district heating systems, and biomass traders evaluating weather resistance
- R&D and process optimization for thermal treatment, feedstock selection, additives and compression parameters to improve moisture resistance
Primary users: standards bodies, certification bodies, QA/QC labs, biomass producers, energy plant operators, and material researchers.
Related Standards
Normative references used by ISO 23343-1:2021 include:
This standard provides a reproducible, worst‑case (post‑immersion) indicator of how thermally treated pelletized biofuels respond to moisture exposure, enabling objective comparisons and informed decisions on storage, handling and specification.