Investigation on gasification of agricultural wastes: the case of macadamia husk

Abstract

Macadamia husk, an overlooked residue of macadamia production, could become a promising feedstock for gasification with the help of extensive engineering knowledge. This study aimed at establishing a comprehensive database of the macadamia husk's characteristics as well as its behaviors during the whole gasification process. The results showed a high heating value of macadamia husk (17.47 MJ/kg) along with its low ash content (3.42 wt%), which is very suitable for thermo‐conversion processes. However, with a relatively high moisture content (15.72 wt%), macadamia husk might require additional pre‐treatment such as drying. The thermal decomposition of macadamia husk, determined through the TGA‐DTG technique, began at 220 °C and reached a maximum mass reduction rate (Rmax = 0.41 %/°C) at 295 °C. The gasification conversion rate was conducted under three distinctive atmospheres: carbon dioxide gasification (20 % CO2 in N2), steam gasification (20 % H2O in N2), and their mixed atmosphere were finished after 560, 495, and 395 s, respectively. The resulting database of this study would be of great use for the design, modeling as well as optimization of a macadamia husk gasifier.

Preliminary characterization of residual char after gasification of rice straw

“…While the volume of micropores was relatively small in proportion to the total volume, it resulted in a significantly high surface area in the rice straw char. This level of porosity is notably higher when compared to other biochars reported in the literature [11,13,18]. These findings emphasize that the residual char possesses adsorption properties attributed to its micropores and mesopores, underscoring its potential as a cost-effective and efficient adsorbent.…”

“…This suggests that they have the potential to replace costly activated carbons [10]. Residues resulting from the gasification of agricultural materials have demonstrated a valuable combination of high carbon content and significant porosity, making them suitable for use as adsorbents [11][12][13]. Additionally, research has confirmed the feasibility of utilizing residues from pinewood gasification as adsorbents for capturing volatile compounds [14].…”