Wet torrefaction of biomass waste into levulinic acid and high-quality hydrochar using H-beta zeolite catalyst

This study delves into how acid catalysts and reaction conditions in WT impact the resulting hydrochar's surface characteristics and elemental composition, as well as the distribution of liquid products. The focus is on utilizing wood cellulose pulp residue (WCPR) as the feedstock with H-Beta zeolite catalyst in a nitrogen-rich environment. The WT process involves a temperature range of 180–260 °C, and reaction durations spanning 15–60 min. The findings reveal that WT conditions, including the catalyst for WCPR, significantly influence the hydrochar's properties and liquid product distribution. With increasing temperature and reaction time, the hydrochar experiences changes, including increased carbon content and reduced oxygen content. The study identifies 260 °C and 30 min as the optimal temperature and time for levulinic acid production, achieving a remarkable selectivity of 62.8% with the H-Beta zeolite catalyst using H2O/WCPR = 10. Various properties of the resulting hydrochar are assessed, including higher heating values (HHVs), decarbonization (DC), dehydrogenation (DH), deoxygenation (DO), enhancement factor, carbon enrichment, surface area, pore diameter, weight loss as well as solid, carbon, hydrogen, and energy yields.