DIRECT MEASUREMENT AND SPECIATION OF VOLATILE ORGANOSILICONS IN LANDFILL GAS BY GAS CHROMATOGRAPHY WITH ATOMIC EMISSION DETECTION

摘要

The presence of volatile organosilicon compounds in landfill gas was known to cause catastrophic combustion engine failure due to the formation of abrasive microcrystalline silica. A sensitive and ready method is required to quantitate the total silicon content and individual species. The total organosilicon measurement provides one of the most critical fuel-gas quality parameter. Speciation provides information on the type, the amount and the distribution of various organosilicon compounds present in landfill gas. This information is of a great value to the utilization of landfill gas for energy production and to the development and evaluation of clean-up processes. A direct measurement method was further developed and modified as a routine laboratory method over the past two years. The volatile organic silicon-containing compounds in landfill gas are separated by gas chromatography (GC) techniques and subsequently detected by an atomic emission detector (AED) using a microwave-induced He plasma (HIP). The characteristic emissions from silicon and carbon of each component are simultaneously monitored for compound confirmation and measurement. The detection limit of each silicon compound is approximately 0.1 mg/m~3 (～0.8 ppmv) as silicon with a 0.25 ml gas sample. The paper details the method and discusses on the issues of gas sampling, sample stability and possible interference, the distribution of organosilicon compounds in landfill gas and future development.