NF EN ISO 2613-1, X20-613-1 (05/2023)

This document is applicable to the measurement of total silicon content in gaseous matrices such as biomethane and biogas. Silicon is present in gaseous form, and contained mainly in siloxane compounds, trimethylsilane and trimethylsilanol. The analytical form of silicon measured in the liquid phase after sampling and derivatization, is a soluble hexafluorosilicate anion stable in slightly acidified media. Total silicon is expressed as a mass of silicon in the volume of the gas analyzed. This document applies to the stated gas matrices, with silicon concentrations up to 5 mg/m3, and mainly concerns biomethane matrices with silicon content between 0.1 mg/m3 and 0.5 mg /m3. With adaptation ensuring appropriate absorption efficiency, it can be used for higher concentrations. The detection limit of this method is estimated at 0.05 mg/m3 for a gas sample volume of 0.020 m3. All compounds present in the gas phase are volatile at the absorption and derivatization temperature, and the gaseous organosilicon compounds are trapped in the absorption medium and then derivatized as analytical silicon which is measured according to the present method. The concentration of silicon is measured in the diluted derivatization medium, by atomic emission spectrometry, after atomization/ionization in a microwave or inductively coupled plasma. Unless otherwise noted, all volumes and concentrations are for normal conditions (temperature, 273 K and pressure, 101.325 kPa). NOTE With appropriate dilution factors, the method can also be applied to silicon concentrations above 5 mg/m3.
(Automatic translation from French)