Radiocarbon-based determination of biogenic and fossil carbon partitioning in the production of synthetic natural gas

The applicability of the radiocarbon (14C) method for the quantification of the biogenic carbon fractions at different stages of the Synthetic Natural Gas (SNG) production process is demonstrated in this study. The 14C-based biogenic carbon fractions were determined in process flue gas and raw SNG and were 38% and 89% respectively, for a mixture of wood and fossil lignite with 75 ± 3% biogenic carbon as input material. The differences in biogenic carbon fractions between the input material, flue gas and raw SNG are caused by bio-fossil carbon partitioning during the SNG production process. This study demonstrates that the main bio-fossil carbon partitioning took place during the gasification of the input material. This is due to the large differences in volatility and char content of the wood and lignite materials. For the determination, verification or certification of the biogenic carbon fraction in process flue gas and (raw) SNG in the SNG production process, separate investigations of the gases are inevitable. The 14C method is a useful and reliable independent method for these purposes.