Effect of methanol-to-oil molar ratio
In order to investigate the effect of molar ratio on biodiesel yields, experiments were conducted with
various molar ratios ranging from 3:1 to 12:1 with a constant catalyst concentration of 1.85 wt.% SrO,
reaction time of 40 sec, reaction temperature of 80o
C, and the speed of magnetic stirring in 600 rpm. The
stoichiometric molar ratio of methanol to oil is 3:1. In bio-diesel making processes with heterogeneous
catalysis, mass transfer and the adsorption of reactants onto the catalyst play an important role. Moreover,
the transesterification reaction consists of a sequence of three consecutive reversible reactions. Thus, the
methanol-to-oil molar ratio should be larger than that of stoichiometric molar ratio in order to shift the
equilibrium conversion of the reaction. The effect of methanol-to-oil molar ratio on the bio-diesel
conversion efficiency was shown in Fig. 5.