Characterization and pilot-scale downdraft gasification of invasive forestry species biomass in the Dominican Republic

In many developing countries, the primary source of energy generation is fossil fuels. However, the study and utilization of invasive forestry species for gasification can help transition away from fossil fuels and towards sustainable, renewable energy production. In the present work, we investigated the characterization and energy potential of four invasive forestry species (Prosopis juliflora, Azadirachta indica, Acacia mangium, and Calliandra calothyrsus) affecting the dry and rain forests of the Dominican Republic. We analyzed the parts (wood, bark, and branches), and transverse diameter sizes (less than 2.5 cm, 2.5–5.0 cm, and 5.0 cm) of the invasive forestry species. Additionally, we evaluated the calorific value, composition, and quality indicators of the syngas produced by these species using a downdraft gasifier. Fixed carbon, ash, and moisture content were higher in the bark compared to the wood and branches of the forestry species. Also, lower the thickness of the species branches tended to have higher moisture and ash content. A. mangium had the highest energy potential with calorific values of 20.4 MJ/kg for the biomass and 5.22 MJ/m³ for the syngas. The species P. juliflora showed a calorific value of 18.6 MJ/kg and syngas with 5.08 MJ/m³. However, the gasifier cold gas efficiency of the species P. juliflora obtained of 24.89 % which was slightly higher than A. mangium with 23.29 % based on the conversion ratio of biomass to gas. Our findings reveal the promising potential of P. juliflora, a relatively underexplored biomass, as a viable feedstock for gasification-based bioenergy production.