The lower biochar yields obtained in this study than those
of obtained from the other biomasses tested in the literature must
have been due to the compositional difference between poultry litter
and the other biomasses. Possibly manure and protein contents
in poultry litter are easily hydrolyzed into water-soluble fragments,
mainly simple amino acids, which do not involve in biochar
formation (Cao et al., 2011). In a similar study of Oliveira et al.
(2013) on HTC of poultry litter, biochar yield obtained from poultry
litter at 180 C for 4 h was 52.5 wt.% and higher than that of
obtained at 175 C for 30 min in this study. This difference in biochar
yields was attributed to the difference in composition of both
poultry litters.