Biodiesel production from castor oil and analysis of its physical properties

Abstract

Biodiesel is a biodegradable, renewable energy and efficient substitution fuel which can fulfill energy security needs without sacrificing engine performance. Biodiesel fuels were prepared from vegetable oil of castor beans and its physical properties such as viscosity, flash point and pour point were studied. The crude castor oil was purified and trans-esterified. Transesterification reaction is most widely used method for biodiesel production, in which the triglycerides in the oil reacts with monohydric alcohol. 200 ml of the castor oil was measured and pre-heated to 70 ^oC using hot magnet stirrer with thermometer. 1.5 ml citric acid was added to the heated oil sample and continuously stirred for 15 minutes at 70 ^oC. 4g of 8 % KOH was then added to the oil and continuously heated and stirred for 15 minutes at 70 ^oC. The mixture was then transferred to the vacuum oven where it was heated at 85 ^oC for 30 minutes. Similarly, 2g of silicon reagent was added while it was being heated and stirred. after 30 minutes the temperature was increased to 85 ^oC and 4g of activated carbon was added to each 100 ml of the oil sample, heated and stirred for 30 minutes and the mixture was separated using filter paper. At 30, 60 and 90 ^oC, the viscosity of crude, purified and transesterified castor oil were found to be (64, 52, 50 mpa.s), (47, 43, 37 mpa.s) and (38, 35 and 30 mpa.s) respectively. This shows that, trans-esterified castor oil has viscosities within similar range with the crude biodiesel oil for all the varying temperatures, indicating that viscosity is major reason why oils and fats are trans-esterified to biodiesel.