A New Method for Predicting the Liquid Dynamic Viscosity of Biodiesel-Related Esters Based on the Corresponding State Principle

Abstract

This work proposes a new model based on the three-parameter corresponding states principle (CSP) for estimating the dynamic viscosity of biodiesel-related esters in the liquid state. A Tait-like equation was employed to extend the model to high-pressure conditions. The model's parameters were fitted to 249 experimental viscosity data points from 11 biodiesel-related esters, with 204 obtained under high-pressure conditions. The average absolute relative deviations were 7.94% for high-pressure conditions and 12.95% for atmospheric conditions. The proposed method was rigorously compared with 13 of the most consolidated models available in the literature for the same property (9 based on the group contribution concept, 3 based on the CSP, and 1 based on both methodologies). Considering all criteria of accuracy and physical consistency, the proposed model is recommended for future applications.

1

(a) ARD distribution and (b) %AARD profile obtained by the most accurate models predicting η considering the carbon number of FAAEs.

2

ARD distribution by the models in the temperature interval. The colors navy, purple, cyan, green, yellow, and red are the models JR, OE, YPP, CGC, NRR, and da Silva 2f, respectively.

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Comparison between generated profiles by CGC (a, b) and da Silva 2f (c, d) models for selected saturated and unsaturated FAMEs.

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Plots of experimental versus calculated P-η-T for FAAEs with high-pressure data using the high-pressure model: (a) correlation set; (b) relative deviations for correlation set; (c) prediction set; (d) relative deviations for prediction set. Dashed lines correspond to ± 10% relative deviation.