Correlations for the prediction of higher heating values of liquid fuels from their densities, viscosities, and flash points values

In this study, correlations of the higher heating values (HHV) of three groups of liquid fuels, vegetable oils, alkanes, and alcohols were developed through experimentation and prediction with the aid of the statistical software package MINITAB 16 (PA, USA). The HHVs (in kJ/kg), of the samples were obtained as a function of the density, viscosity, and flash points physical tests. Reliability of models were evaluated through statistical validation and cross-validation standard error of estimate (S), coefficient of determination (R 2 ), predicted residual error of the sum of square statistics (PRESS statistics), error estimations (average bias error, ABE, and AAE, average absolute error), and the residual versus fitted values plot. For the vegetable oils, the best correlation was HHV = -29.5 + 77.8ρ -0.0124μ + 0.00549β (R 2 = 79.6%, p -value = 0.147, AAE = 0.515, ABE = 0.005). For alkanes it was: HHV = 66.0322 – 38.3421ρ + 2.9392μ (R 2 = 100%, p -value = 0.002, AAE = 0.033, ABE = 7.27 × 10 -5 ). For alcohols; HHV = -100 + 171ρ (R 2 = 86.4%, p -value = 0.070, AAE = 4.193, ABE = 0.316). These correlations could be instrumental to achieving maximum productivity with minimal utilization of energy in industry and could be extended to other liquid fuels after minor modification.