title: Development of on-line FTIR spectroscopy for siloxane detection in biogas to enhance carbon contactor management.
abstract: Activated carbon filters are used to limit engine damage by siloxanes when biogas is utilised to provide electricity. However, carbon filter siloxane removal performance is poorly understood as until recently, it had not been possible to measure siloxanes on-line. In this study, on-line Fourier Transform Infrared (FTIR) spectroscopy was developed to measure siloxane concentration in real biogas both upstream (86.1-157.5mg m(-3)) and downstream (2.2-4.3mg m(-3)) of activated carbon filters. The FTIR provided reasonable precision upstream of the carbon vessel with a root mean square error of 10% using partial least squares analysis. However, positive interference from volatile organic carbons was observed in downstream gas measurements limiting precision at the outlet to an RMSE of 1.5mg m(-3) (47.8%). Importantly, a limit of detection of 3.2mg m(-3) was identified which is below the recommended siloxane limit and evidences the applicability of on-line FTIR for this application.
authors.affiliation: Cranfield Water Science Institute, Cranfield University, Bedfordshire MK43 0AL, UK.
authors.forename: C A
authors.initials: CA
authors.lastname: Hepburn
authors.affiliation: Severn Trent Water Limited, Coventry CV1 2LZ, UK.
authors.forename: P
authors.initials: P
authors.lastname: Vale
authors.affiliation: National Physical Laboratory, Teddington, Middlesex TW11 0LW, UK.
authors.forename: A S
authors.initials: AS
authors.lastname: Brown
authors.affiliation: Centre for Power Engineering, Cranfield University, Bedfordshire MK43 0AL, UK.
authors.forename: N J
authors.initials: NJ
authors.lastname: Simms
authors.affiliation: Cranfield Water Science Institute, Cranfield University, Bedfordshire MK43 0AL, UK. Electronic address: e.mcadam@cranfield.ac.uk.
authors.forename: E J
authors.initials: EJ
authors.lastname: McAdam
mesh_terms: D056804:Biofuels / Q000032:analysis*; D002138:Calibration; D002244:Carbon; D005374:Filtration / Q000191:economics / Q000295:instrumentation; D016018:Least-Squares Analysis; D057230:Limit of Detection; D012833:Siloxanes / Q000032:analysis*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*; D055549:Volatile Organic Compounds / Q000737:chemistry; D014865:Waste Disposal, Fluid / Q000295:instrumentation / Q000379:methods
chemical_list: D056804:Biofuels; D012833:Siloxanes; D055549:Volatile Organic Compounds; D002244:Carbon
keywords: Adsorption; Biogas; CHP; Interference; Landfill; VOCs