Optimización de la producción de biogás a través de la hidrólisis de residuos madereros

Abstract

Sawdust is one of the most common residues in sawmills, and its transformation into biogas represents a strategic approach to sustainability and energy production. The main objective of this study is the production of biogas from wood waste. Thermal pretreatment was applied at three different temperatures (55, 65, and 80 °C), and alkaline pretreatment was performed with three concentrations of NaOH (0.1%, 0.25%, and 0.5%) to produce biofuels suitable for domestic use. Sawdust was used as raw material in a batch-type bioreactor to generate biogas. Variables such as the amount of pretreated lignocellulosic residue and its pH were monitored, and quantitative data were collected, including the amount of biogas produced. Homemade bioreactors were loaded with 350 g of pretreated sawdust, 50 g of urea dissolved in water, 200 g of molasses, and 0.5 liters of cow manure dissolved in 3 liters of water. This mixture was fermented for 37 days in a greenhouse to produce the desired biogas. The gaseous fraction of the best pretreatment was analyzed using gas chromatography (ASTM D 1945), while the liquid fraction was evaluated via FT-IR spectroscopy. Statistical analysis was performed using ANOVA. The chromatographic analysis revealed a biogas mixture with a composition of CH₄ (41.5%), H₂ (16.35%), O₂ (2.2%), N₂ (9.51%), and CO₂ (17.6%). Alkaline pretreatment demonstrated superior efficiency, yielding an average biogas volume of 7.2 liters, compared to 2 liters obtained from the best thermal treatment. The study concludes that biogas production using alkaline hydrolysis pretreatment with 0.25% NaOH is more effective than untreated residues or the control group.