BS EN ISO 2613-2:2023

Analysis of natural gas. Silicon content of biomethane. Determination of siloxane content by gas chromatography with ion mobility spectrometry | Status: Current

1 Scope This document describes a gas chromatography – ion mobility spectroscopy (GC-IMS) method for the determination of the concentration of siloxanes in biomethane. The method is applicable to the following siloxanes:

• — hexamethyldisiloxane (L2);
• — octamethyltrisiloxane (L3);
• — decamethyltetrasiloxane (L4);
• — dodecamethylpentasiloxane (L5);
• — hexamethylcyclotrisiloxane (D3);
• — octamethylcyclotetrasiloxane (D4);
• — decamethylcyclopentasiloxane (D5);
• — dodecamethylcyclohexasiloxane (D6).

This document describes suitable calibration and measurement strategies to quantify siloxanes in (bio)methane around and above the 0,3 mg m-3 (14 µmol mol-1) level and applies to analyses within absolute pressure ranges of 1 bar – 2 bar1, temperatures of 0 °C – 40 °C and relative humidity < 90 %.