Experimental investigation of jojoba as a renewable energy source

This work examined jojoba (oil and cake) as possible alternative fuel sources. Jojoba is a shrub that grows very well in deserts and its cake is the solid part produced upon processing of the jojoba seeds for oil extraction. In this study, pure jojoba oil and 50/50 blends with diesel fuel were tested as fuels in a single cylinder diesel engine. The diesel fuel was the baseline of comparison throughout the runs. The cake was tested for both direct combustion (pellets) and as a substrate for biogas production. The pellets were formed by compacting the cake in cylindrical dies using a hydraulic press while the biogasification was conducted in an anaerobic digester model Bioflo 110 from Brunswick. The findings indicate that the optimum injection pressure for jojoba oil in the engine is 210 bars at which engine speed was maximum (2700 rpm), NOx and CO emissions as well as exhaust temperature were minimum. Using jojoba cake for biogasification resulted in a yield of about 600 ml biogas per 400 g of jojoba cake. Burning jojoba compacted cake (pellets) for direct combustion in a stove indicated that jojoba cake sustained a temperature in excess of 300 degrees C for a reasonable amount of time and that the cake was very competitive to wood and has energy content more than most types of wood. Overall, it may be stated that both jojoba oil and cake hold real promise as alternative energy sources. (C) 2009 Elsevier Ltd. All rights reserved.