Resumo (PT):
Abstract (EN):
This work evaluates the possibility of using
spent coffee grounds (SCG) for biodiesel production and
other applications. An experimental study was conducted
with different solvents showing that lipid content up to
6 wt% can be obtained from SCG. Results also show that
besides biodiesel production, SCG can be used as fertilizer
as it is rich in nitrogen, and as solid fuel with higher
heating value (HHV) equivalent to some agriculture and
wood residues. The extracted lipids were characterized for
their properties of acid value, density at 15 C, viscosity at
40 C, iodine number, and HHV, which are negatively
influenced by water content and solvents used in lipid
extraction. Results suggest that for lipids with high free
fatty acids (FFA), the best procedure for conversion to
biodiesel would be a two-step process of acid esterification
followed by alkaline transesterification, instead of a sole
step of direct transesterification with acid catalyst. Biodiesel was characterized for its properties of iodine number, acid value, and ester content. Although these quality
parameters were not within the limits of NP EN
14214:2009 standard, SCG lipids can be used for biodiesel,
blended with higher-quality vegetable oils before transesterification, or the biodiesel produced from SCG can be
blended with higher-quality biodiesel or even with fossil
diesel, in order to meet the standard requirements.
Tipo (Avaliação Docente):
Científica
Nº de páginas:
8