Interest in the measurement of siloxane which reduces energy efficiency of biogas, has increased with its market extend. Even though the impinger absorption method takes long sampling time of 2-3 hours and need a complicated equipment, it has been typically used for the sampling method of siloxane. This study was conducted to apply the gas bag sampling method with tedlar bag and aluminium bag for improving the method of siloxane sampling. To compare efficiencies of siloxane sampling, the manufactured gas, landfill gas, and digestion gas were used as sample gases. According to the result, materials of gas bags did not cause measurement error and there was no loss of siloxane by adsorption on the inner surface of gas bag. The result of D4 calibration in the tedlar bag, showed higher than 0.99 in the coefficient of determination. In case of digestion gas, the analysis results of two samples collected by the tedlar bag and the impinger absorption were almost same. The differences of analysis result between landfill gas and digestion gas were considered due to the short sampling time and the absence of gas storage tank.

This study was conducted to improve the analytical method of siloxanes in biogas. Methanol and hexane were tested as absorption solvents of the impinger absorption method, and also the hexane extraction for pretreatment of sample was evaluated. Manufactured gas contained siloxanes of 50 ppm was completely absorbed by the methanol impinger absorption. The absorption efficiency of biogas containing only 2 ppm, however, was maximum 84%. As the condensate on the first impinger increased, the absorption rate of methanol was decreased. The hexane extraction method of the sample was considered to proper the method of moisture removal. The hexane extraction result showed the high recovery factor and the low relative standard deviation. It is suggested that the suitable choice of solvent and pretreatment is required, as the analysis result of siloxane sample may be differentiated depending on the type of biogas or the sampling point.