RESUMEN
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, â¼5 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.
RESUMEN
Waste polypropylene (PP) has been pyrolysed to obtain mainly a liquid tar product of high yield (83.5%) with the balance as gas (15.5%) and a little residue (1.0%). The elemental composition of the PP tar was: C: 87.1%, H: 12.6% and O+others: 0.4% (by difference). The tar samples have been characterised by gas chromatography/mass spectrometry, heated-probe mass spectrometry and laser -desorption mass spectrometry (LD- MS), to give molecular mass distributions for comparison with molecular mass ranges indicated by size-exclusion chromatography (SEC). About 50% of the tar was soluble in 1-methyl-2-pyrrolidinone, the solvent used for SEC. It appeared to consist mostly of low molecular mass materials with elution time at 20-27 min. Mass ranges from SEC and LD-MS agreed approximately in showing the upper mass limit of the tar to be about 1200 u, consisting of aromatics, alkenes, dialkenes and only minor quantities of alkanes.
RESUMEN
The size-exclusion chromatography (SEC) of acetone-soluble, pyridine-soluble and pyridine-insoluble fractions of a coal tar pitch indicates a bimodal distribution in each fraction. The proportion of high-mass material excluded from the SEC column porosity increases with solvent polarity. The polymer calibration of SEC shows the mass range of the small molecules to be from approximately 100 u to approximately 6000 u, with the mass range of the large excluded molecules above 200 000 u and up to several million u. In contrast, matrix-assisted laser desorption/ionisation mass spectrometry (MALDI-MS) shows a similar low-mass range of ion abundances (< m/z 6000), but with a smaller range of high-mass ion abundances, from approximately m/z 10 000 to 100 000. The large molecules may have three-dimensional structures to allow molecules of relatively low mass to behave as if they are of large size in SEC. Laser desorption mass spectrometry of the acetone- and pyridine-soluble fractions produced molecular ions of polycyclic aromatics that can be related to the known compositions from gas chromatography (GC) mass spectrometry. The experimental conditions used to generate the bimodal distribution by MALDI-MS involve reducing the ion signal intensities to avoid overload of the detector and enable detection of the high-mass ions, by reducing the high-mass detector voltage (i.e. sensitivity) and increasing the laser power.