Combustion characteristics of Torrefied corncob and African birch wood residues at higher heating rate

The torrefaction of biomass generated from by-products of post-harvest agricultural activities such as corncob or woody residues from saw milling, pruning, and furniture production such as African birch wood, are renewable energy sources whose pyrolytic and combustion properties are crucial during process heating in various applications. This study investigated the combustion characteristics of corncob and African birch wood residues at a higher heating rate and their comparative energy qualities. Samples of corncob and African birch wood residues were collected, sorted, pulverised into particles, and torrefied independently. The raw and torrefied corncob and African birch wood particles were screened into 0.3, 0.5, and 1.0 mm sizes, and their thermogravimetric, proximate, ultimate, heating values, and energy quality analyses were carried out. The torrefied biomass showed better pyrolytic and combustion characteristics relative to the raw samples. However, African birch wood residues appear to be better than corncob residues. The higher heating values (HHVs) ranged from 21.46 to 21.63 MJ/kg and 23.1 to 25.6 MJ/kg for the torrefied samples of corncob and African birch wood residues, respectively. The torrefied sample of African birch wood residues exhibited the highest HHV (25.6 MJ/kg), which compared favourably with the value from a low-rank coal, such as lignite or brown coal. Torrefied African birch wood residues, with their high HHV, can be densified to replace low-rank coal and firewood in a variety of applications.