Abstract
Oil shale ash obtained from combustion of local oil shale deposits was used in this study as a heterogeneous catalyst to produce biodiesel from waste vegetable oil (WVO). Two alcohols with high and low boiling points, ethanol and ethylene glycol, were used for oil shale catalytic esterification of the WVO. Results show that the esterification of wastes of oil utilizing wastes of oil shale combustion can be used to produce biodiesel. Additionally, it was found that in order to make the oil shale ash an effective catalyst for transesterification, high reaction temperature is required. Therefore, the results have indicated that high biodiesel yield is obtained when using ethylene glycol at high temperature, while the yield is low when solid catalytic reaction is performed using ethanol at low temperature. The maximum obtained yield was 75 wt. % utilizing ethylene glycol at 150 degrees C, whereas this yield decreased to 69.9 wt. % as the operating temperature was reduced to 100 degrees C. On the other hand, when using ethanol, the yield of biodiesel was relatively low (11 wt. % at 60 degrees C and 9wt. % at 80 degrees C). (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4768544]