ISO 10370:2014

Overview

ISO 10370:2014 - "Petroleum products - Determination of carbon residue - Micro method" - specifies a laboratory micro-method to measure the amount of carbon residue remaining after evaporation and pyrolysis of petroleum products. The method covers residues in the range 0.10 % (m/m) to 30.0 % (m/m) and provides a rapid, small-sample test to assess carbon-forming tendencies of fuels and oils under controlled conditions.

Key topics and technical requirements

• Test principle: A weighed aliquot is heated to 500 °C under an inert nitrogen purge; volatiles are swept away and the remaining carbonaceous residue is weighed.
• Measurement range: 0.10–30.0 % (m/m). For very low-residue distillates, a 10 % (V/V) distillation residue is prepared prior to analysis.
• Apparatus and materials: 2 ml (typical) or 4 ml glass sample vials, coking oven capable of controlled heating to 500 °C, low-oxygen nitrogen (≥99.998 % V/V) supply, thermocouple, analytical balance with 0.1 mg sensitivity, vial holder and desiccator.
• Operating conditions: Nitrogen purge, controlled heat ramp (10–40 °C/min allowed; recommended 10–15 °C/min to 500 °C), hold at 500 °C ±2 °C for 15 min, cool under nitrogen before reweighing.
• Sample sizes: Vary by expected residue (e.g., 0.15 g for viscous samples, up to 3.0 g for low residues in 4 ml vials).
• Interferences and inclusions: Ash-forming constituents and non‑volatile additives are included in the reported carbon residue. Presence of organic/alkyl nitrates can artificially raise results (see ISO 13759 for detection).
• Equivalence: For residues >0.10 % (m/m), results are equivalent to the Conradson carbon residue test (ISO 6615) over much of the common range (see Annex A).

Applications and who uses it

ISO 10370 is used by:

• Quality control and analytical laboratories in refineries and fuel producers
• Petrochemical and lubricant manufacturers assessing deposit-forming potential
• Fuel additive developers evaluating additive volatility and non‑volatile contribution
• Regulatory and standards bodies for comparative product assessment

Practical applications include routine QC of fuels and lubricants, comparative screening of carbon-forming tendency within product classes, and supporting formulation decisions to reduce deposit risk.

Related standards

• ISO 6615 - Conradson carbon residue method (reference for equivalence)
• ISO 3405 - Distillation characteristics (used for preparing 10 % distillation residue)
• ISO 6245 - Ash in petroleum products (definition of ash-forming constituents)
• ISO 13759 - Detection of alkyl nitrates in fuels

ISO 10370 is a compact micro-method offering reliable, small-sample measurement of carbon residue - ideal for routine laboratory testing and comparative evaluations of petroleum product deposit tendencies.