Waste-to-energy in the civil-construction sector toward the valuation of wood construction residues: Integration of torrefaction process

As Brazil’s construction industry plays a pivotal role in its economy, there is growing interest in sustainable alternatives, particularly waste-to-energy solutions. Wood waste from the construction industry (WCW) is a biomass source with economic value applications and can be used in the market as fuel. One of the bottlenecks of implementing WCW in urban centers is the continuous availability of materials to meet the demand, which is allied with the WCW contaminations and promotes high ash content. Therefore, blend formation has emerged as a solution to maximize the use of this waste and minimize the ash content, addressing issues such as machinery corrosion and slag formation during combustion. This study forwards improving the use of WCW as a biofuel via torrefaction by proposing an original blend of 50:50 WCW and Eucalyptus sp., torrefied at 200 (B200), 250 (B250), and 300 °C (B300) for 50 min. A comprehensive analysis assessed torrefaction process performance (kinetics and indexes), evaluating ultimate, proximate, physical (bulk density and SEM), bioenergy density, and energetic properties, examining combustion behavior and related emissions of the biofuel. Results highlight the most efficient treatment, B250, with 1.24 % ash, 20.76 MJ kg−1 heating value, 86.88 % mass yield, 91.25 % energy yield, and 6.38 bioenergy density. Replacing 1 m3 of oil, diesel, fuel oil, gasoline or 1 ton of coal with B250 could reduce CO2eq emissions by 590.88, 620.85, 469.68, 770.49, and 1894.4 kg, respectively. The study aligns with SDGs 7, 11, 12, and 13, promoting sustainable cities, responsible waste management, and climate action.