Experimental assessment of oxy-CO₂ gasification strategy with woody biomass

This paper presents the results obtained during an extensive experimental campaign focused on analysing the application of Oxy-CO₂ gasification technology to a small downdraft gasifier fed with woody biomass. Oxy-gasification enables the production of a nitrogen-free synthesis gas (syngas), which can be effectively employed in the synthesis of various high-value chemicals, including but not limited to synthetic natural gas (SNG), methanol (CH₃OH), ammonia (NH₃), hydrogen and more. The gasifier performances were analysed using different CO₂/O₂ ratios in the feed (between 1 and 3 kg/kg). The inlet biomass flow rate was approximately 12–18 kg/h, while the equivalence ratio ranged between 19 % and 26 %. The results show that the gasifier can produce a syngas flow rate in the range of 15–25 Nm³/h with a lower heating value (LHV) of between 8 and 10 MJ/Nm³ and a cold gas efficiency of up to 78 %. The operative behaviour of the gasification system is stable and simple to control.