Impact of Hydrolysis on Thermal Stability and Binding Capacity of Torrefied-densified Iron (Lophira Alata) Wood Dust

This project examined the impact of hydrolysis on the thermal stability and binding capacity of torrefied-densified wood biomass from the red iron tree (Lophira alata), with the goal of utilizing it as a feedstock for pellet fuel. Initial analysis, including proximate, ultimate, fiber, and physico-chemical analysis, were conducted on raw wood dust samples before hydrolysis and torrefaction. The wood dust sample with the highest energy value from the hydrolyzed-torrefied samples was investigated as a potential feedstock. Physico-chemical analysis of the raw biomass samples were conducted before torrefaction and hydrolysis treatments. Torrefaction experiments were conducted on the raw and hydrolyzed samples at various process temperatures (200 °C, 250 °C, and 300 °C) for 45 minutes in a custom-made laboratory-scale torrefier. The results showed that hydrolyzed and torrefied wood dust samples differed in color from the untorrefied (raw) samples, indicating the physical impact of the treatment methods. As process temperature increased, higher heating value (HHV) rose, while energy yields decreased. Proximate analysis revealed that hydrolysis significantly improved the fixed carbon content of the wood dust biomass, with a remarkable increase in hydrolyzed samples compared to their unhydrolyzed counterparts. The highest fixed carbon content (91.66 %) was achieved with the hydrolyzed sample torrefied at 283 °C, while the lowest value (74.79 %) was recorded in the unhydrolyzed sample. Similarly, hydrolysis affected fiber composition, with lignin content increasing to 35.33 % in the hydrolyzed-torrefied sample, compared to 15.43 % in the unhydrolyzed sample. Ultimate analysis showed lower H/C and O/C values (0.003 and 0.100, respectively) in the hydrolyzed sample, indicating enhanced thermal stability and energy value. These results demonstrate that hydrolysis prior to torrefaction significantly impacts lignin content, binding capacity, fixed carbon, and energy value, making hydrolyzed-torrefied wood dust biomass of Lophira alata a promising feedstock for pellet fuel production.