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.