Pongamia, a leguminous,
oilseed-bearing tree, is a potential resource
for renewable fuels in general and sustainable aviation fuel in particular.
The present work characterizes physicochemical properties of reproductive
materials (seeds and pods) from pongamia trees grown in different
environments at five locations on the island of Oahu, Hawaii, USA.
Proximate and ultimate analyses, heating value, and elemental composition
of the seeds, pods, and de-oiled seed cake were determined. The oil
content of the seeds and the properties of the oil were determined
using American Society for Testing and Materials and American Oil
Chemist’s Society methods. The seed oil content ranged from
19 to 33 wt % across the trees and locations. Oleic (C18:1) was the
fatty acid present in the greatest abundance (47 to 60 wt %), and
unsaturated fatty acids accounted for 77 to 83 wt % of the oil. Pongamia
oil was found to have similar characteristics as other plant seed
oils (canola and jatropha) and would be expected to be well suited
for hydroprocessed production of sustainable aviation fuel. Nitrogen-containing
species is retained in the solid phase during oil extraction, and
the de-oiled seed cake exhibited enrichment in the N content, ∼5
to 6%, in comparison with the parent seed. The pods would need further
treatment before being used as fuel for combustion or gasification
owing to the high potassium and chlorine contents.