Accelerator mass spectrometry for tracing fossil carbon content of combusted fuel

Fossil CO₂ emission inventory from waste incineration plants needs to be determined for the purpose of emission trading in the future. A fundamental method for this is to measure the ¹⁴C content of the exhaust gas using accelerator mass spectrometry (AMS) and deduce fossil/biofraction from it. Conventionally, the CO₂ in the sampled exhaust gas has been graphitized for the AMS measurement. In this work we have tested a method where the sample is fed to the AMS system in gas form, without the extra graphitizing step. The sample gas storage and feeding system of Helsinki Accelerator Laboratory is represented along with the results obtained in the test with flue gas samples from test combustion facility. The results show that the analysis of biofraction of combusted fuels is possible in feasible, reproducible and accurate ISO13833 standard compliant way with the tested method.