Effects of Temperature and Biodiesel Fraction on Dynamic Viscosities of Commercially Available Diesel Fuels and Its Blends with the Highest Methyl Ester Yield Corn Oil Biodisel Produced by Using KOH

Abstract

The objective of this chapter is to determine the effects of biodiesel fraction in blend (X) and temperature (T) on dynamic viscosities of the highest methyl ester content corn oil biodiesel and its blends with commercially available diesel fuel. For this objective, first, the highest methyl ester content corn oil biodiesel was produced by using potassium hydroxide (KOH) as catalyst and methanol (CH₃OH) as alcohol, and the biodiesel was blended with commercially available diesel fuel at the volume ratios of 5, 10, 15, and 20%. Then, dynamic viscosities of pure biodiesel and diesel fuel, their blends were measured at different temperatures of 10, 20, 30, and 40 ^°C by following DIN 53015 test methods. From the obtained experimental data, one- and two-dimensional models as a function of X or T were derived using the least square regression for estimating dynamic viscosity values of pure fuels or fuel blends. Also, these models were compared to previously published models and measurements to show their validities. According to regression analysis results, among the proposed one-dimensional models, rational ones such as μ = μ(X) = (aX + 1)/(b + cX) with minimum correlation coefficient (R) value of 0.9942 and maximum error value of 4.5976%, μ = μ(X) = (a ∙ X + 1)/(b + c ∙ X) and power ones such as μ = μ(T) = aT^b + c with minimum R value of 0.9914 and maximum error value of 3.9733% better represent the dynamic viscosity–biodiesel fraction and dynamic viscosity–temperature relationship, respectively, and these models give higher accuracies for predicting viscosity values. Also, two-dimensional combination surface model including exponential and linear terms such as μ = μ(T, X) = a ∙ e^bT + c ∙ e^dX + eX with the higher R value of 0.9952 and lower maximum error value of 3.2319% was recommended for demonstrating the variations in dynamic viscosity values with respect to biodiesel fraction and temperature simultaneously. Furthermore, the quality of the corn oil biodiesel and its blends were evaluated by determining the other important fuel properties, such as kinematic viscosity, flash point temperature, and higher heating value.