From proof to practice - Sampling and analysis for simplified quantification of siloxanes in biogas

Abstract

Siloxanes in biogas pose significant challenges to energy systems, leading to operational inefficiencies and increased maintenance costs. This study advances the liquid quench sampling system (LQ) for accurate quantification of siloxanes using gas chromatography hyphenated with inductively coupled plasma mass spectrometry (GC-ICP-MS). The LQ demonstrated a capture efficiency exceeding 94 % over a broad concentration range, with sample stability tests indicating < 10 % analyte loss over four weeks. A Round Robin Test with nine independent laboratories validated the method's reliability. Calibration with liquid standards is demonstrated, eliminating complications associated with gaseous standards. On-site sampling with centralized analysis makes the method feasible for facilities lacking advanced instrumentation. By accurately quantifying siloxanes, this approach supports optimization of gas cleaning systems to extend equipment life. This LQ-GC-ICP-MS method enables practical sampling and simplified quantification for effective siloxane monitoring to enhance biogas utilization.

Keywords: Bioenergy; Gas chromatography; Gas metrology; Inductively coupled plasma mass spectrometry; Liquid quench sampling; Trace impurities.