Overview
ISO 16995:2015 specifies a standardized laboratory method for determining the water soluble chloride, sodium and potassium in solid biofuels. The method uses water extraction in a closed container followed by instrumental or titrimetric quantification. Results help assess components that influence corrosion, fouling and slagging during thermal conversion of biofuels.
Key Topics and Requirements
- Scope: Extraction of water‑soluble chloride, sodium and potassium from solid biofuel samples and quantification by approved analytical techniques.
- Sample preparation: Use a general analysis sample milled to ≤1 mm (per EN 14780); determine moisture concurrently if results are reported on a dry basis (ISO 18134-3).
- Extraction procedure: Typical extraction uses 1.0 g sample + 50.0 ml deionized water in a fluoropolymer (or borosilicate for chloride-only) vessel, heated at 120 °C for 60 min in a closed oven/autoclave, cooled, made up to 100 ml and filtered (0.45 μm).
- Detection methods:
- Chloride: Ion chromatography (IC, ISO 10304-1) or potentiometric titration with silver nitrate (Standard Methods 4500‑Cl‑D).
- Sodium & Potassium: ICP‑OES (ISO 11885), flame atomic absorption spectroscopy (FAAS, ISO 9964‑1/2) or flame emission spectrometry (FES, ISO 9964‑3).
- Quality controls: Perform blank tests to correct for reagent and laboratory contamination. Use standard addition or dilution checks for instrumental interferences. Report mean of duplicate determinations.
- Calculation & reporting: Subtract blank values and calculate mg/kg on the chosen basis; convert between bases using ISO 16993 where required.
Applications and Who Uses It
- Biofuel producers and processors - to characterize feedstock and optimize storage/processing to reduce formation of volatile salts.
- Power plants, boiler operators and utilities - to evaluate ash behavior and risk of corrosion, slagging and fouling from fuels (wood chips, straw, olive residues, etc.).
- Analytical testing laboratories and certification bodies - for standardized reporting and compliance testing.
- Researchers and equipment manufacturers - to correlate soluble alkali and chloride concentrations with emission profiles and material performance.
Related Standards
- ISO 9964‑1/2/3 - sodium and potassium determination (FAAS/FES)
- ISO 10304‑1 - ion chromatography for anions
- ISO 11885 - ICP‑OES methods
- ISO 16993 - conversion of analytical results between bases
- ISO 18134‑3 - moisture (oven dry) for sample basis
- EN 14780 - sample preparation for solid biofuels
ISO 16995:2015 provides a reproducible, industry‑accepted method to quantify the water‑soluble fraction of aggressive inorganic species in solid biofuels - essential data for fuel quality control, combustion performance assessment and regulatory compliance.
Open preview (PDF)Solid biofuels — Determination of the water soluble chloride, sodium and potassium content