Thermal energy recovery and valorisation of Delonix regia stem for biochar production

Abstract

This study investigated the valorisation of Delonix regia stem wastes for thermal energy and material recovery. Using a retort heated carbonization reactor, the waste biomass was thermochemically converted to biochar via the carbonization method. The proximate analyses of the stem feedstock was determined, and the result showed that it is made up of a moisture content, ash content, fixed carbon, and volatile matter of 4.48 ± 0.15, 5.39 ± 0.18, 23.0 ± 0.60, and 67.11 ± 0.87, respectively. A biochar yield of 26.57 wt% was achieved at a maximum temperature of 500 °C and a heating period of 90 min. The raw biomass and generated biochar were characterized to determine the porous nature, surface area, functional groups, and thermal stability of the samples. With respective specific surface areas of 211 and 356 m2/g, the biomass and biochar are both mesoporous and have pore diameters > 2 nm but < 50 nm. The biochar's existence of functional groups, like OH and C = O, as determined by FTIR analysis points to its potential use as a soil amendment and adsorbent for removing pollutants from water. The biochar has a maximum thermal degradation temperature of 390 °C compared to raw biomass's maximum temperature of 340 °C.

Keywords

• Biochar
• Delonix regia
• Waste treatment
• Thermal energy
• Product development