Brown hemp methyl ester: Transesterification process and evaluation of fuel properties

The present study was conducted to standardize the esterification process parameters for the production of methyl ester of raw hemp oil. The effect of process parameters such as molar ratio, catalyst concentration, and reaction time was studied to standardize the esterification process and for estimating the highest recovery of ester with lowest possible viscosity. Based on the observations from the ester recovery and kinematic viscosity, it can be seen that raw hemp oil at 6:1 M ratio may be reacted with methanol at 60 degrees C reaction temperature for 45 min in the presence of 2 g of KOH and then allowed to settle for 24 h in order to get lowest kinematic viscosity with ester recovery of 90.62%. The yield of hemp methyl ester was found to be 90.62% with oil methanol ratio of 0.37 w/w and 0.01 w/w alkali catalyst. Different fuel properties such as density, kinematic viscosity, flash point, fire point, cloud point, pour point, free fatty acid content and calorific value of the hemp methyl ester and hemp oil were measured. From the properties and engine test results it has been established that methyl ester of hemp oil can be substituted for diesel oil. Methyl ester of above non-edible oil has several advantages among other new renewable and engine fuel alternatives along with its environmental benefits. (C) 2012 Published by Elsevier Ltd.