Date (Phoenix dactylifera L.) palm stones as a potential new feedstock for liquid bio-fuels production

In the present investigation, Date (Phoenix dactylifera L.) stones were utilized in the production of different types of biodiesel in addition to bio-oil. The oil was extracted from the date stones with a yield of 10.50 wt% and is used in the production of fatty acid methyl, ethyl and mixed methyl/ethyl esters via KOH- catalyzed transesterification process with methanol, ethanol and mixed methanol and ethanol, respectively. Properties of the obtained biodiesels, such as the density, kinematic viscosity, flash point, acid value, cloud and pour points, total and free glycerin contents and the refractive index were evaluated and found comparable to those of ASTM D 6751 biodiesel. The FTIR spectroscopy confirmed conversion of date stone oil to biodiesel. The date stones were also tested as new non-edible feedstock for bio-oil production by pyrolysis process in a semi batch reactor. The influence of the pyrolysis temperature, pyrolysis time and precursor particles size on the bio-oil yield was investigated. Maximum bio-oil yield (52.67% +/- 1.50) was obtained at 500 degrees C pyrolysis temperature with a pyrolysis time of 60 min and feed particle size of 0.25 mm. The ultimate analysis, FTIR spectroscopy and adsorption column chromatography were determined to characterize the chemical composition of the obtained bio-oil. Furthermore, several important fuel properties, like the density, kinematic viscosity, flash point, pour point and the acidity index of date stones bio-oil were also determined following ASTM standard test methods and found comparable to those documented for other bio-oils in literature. The chemical composition of the bio-oil produced through pyrolysis of date stones showed the potential of date stones as an important source of alternative fuel and chemicals as well.