Résumé
This study presents a comprehensive techno-environmental evaluation of co-gasification using hybrid blends of municipal solid waste (MSW) and torrefied urban forest waste (UFW) in Brasília, Brazil. Utilizing experimental data from torrefaction treatment, gasification modeling via a thermodynamic equilibrium model, and Life Cycle Assessment (LCA), two syngas production scenarios were examined: (i) hydrogen-rich gas and (ii) enhanced calorific value gas. The optimized gasification system operated at 600°C, exploring two ideal conditions: 0.9 S/B with a blend of 31% MSW and 69% torrefied UFW at 275°C, and 0.4 S/B with a blend of 23% MSW and 77% torrefied UFW at 275°C. Employing LCA Expert (Sphera-GaBi) software with the CML 2001 methodology, the LCA identified primary environmental impacts, focusing on Global Warming Potential (GWP) and Acidification Potential (AP). Scenario (i) exhibited lower GWP impacts (0.779 kg CO2 eq./Nm³ syngas) compared to Scenario (ii) (0.840 kg CO2 eq./Nm³ syngas) while demanding less from the energy matrix (0.154 vs. 0.181 kg CO2 eq.). In the Acidification Potential (AP) category, although scenario (i) (9.04E-04 kg SO2 eq./Nm³ syngas) also demonstrates lower impact compared to scenario (ii) (1.06E-03 kg SO2 eq./Nm³ syngas), only the energy demand was identified as a contributor to the impacts, with no significant emissions to air, in both the torrefaction and gasification processes. The results highlight the necessity of considering environmental, technological, and economic factors for informed decision-making in waste management, advocating for the integration of torrefaction and gasification processes as a viable pathway for sustainable energy production, and aligning with global trends toward cleaner hydrogen energy sources. Further research expanding the LCA to a cradle-to-grave approach is recommended to assess the benefits of these integrated processes fully.