Hydrothermal Liquefaction of Sugarcane Bagasse and Straw: Effect of Operational Conditions on Product Fractionation and Bio-Oil Composition

In the energy transition process, aiming for zero disposal and clean production in the elimination of waste is crucial; consequently, agricultural residues have significant potential for reduction in the use of fossil fuels. This study investigates the hydrothermal liquefaction (HTL) of sugarcane bagasse (BSC) and straw (SSC), examining the products’ distribution and bio-oil composition relative to the reaction conditions. The experiments used a 23 factorial design, evaluating the temperature (300–350 °C), constant heating time (0–30 min), and the use of the K2CO3 concentration as the catalyst (0–0.5 mol/L−1). The main factor affecting the biocrude yield from BSC and SSC was the use of K2CO3. Statistically significant interaction effects were also observed. Milder conditions resulted in the highest bio-oil yields, 36% for BSC and 31% for SSC. The catalyst had no impact on the biocrude production. The bio-oils were analyzed by GC/MS and FTIR; a principal component analysis (PCA) was performed to evaluate the samples’ variability. The FTIR highlighted bands associated with common oxygenated compounds in lignocellulosic biomass-derived bio-oils. The GC-MS results indicated a predominance of oxygenated compounds, and these were highest in the presence of the catalyst for both the BSC (90.6%) and SSC (91.7%) bio-oils. The SSC bio-oils presented higher oxygenated compound contents than the BSC bio-oils. Statistical analysis provided valuable insights for optimizing biomass conversion processes, such as determining the optimal conditions for maximizing product yields.