Analysis of flash point predictions of tailor-made green diesel by UNIFAC group contribution methods

Flash point is one of the most important properties of engine fuel that indicates the lowest temperature at which sufficient flammable vapours have evaporated to allow for ignition. in this paper,the applicability of liaw model to predict the flash point of miscible tailor-made green diesel blends through unifac type models (original unifac and modified unifac (dortmund)) is analyzed. the predictions are compared with the experimental data of pseudobinary mixtures of b5 palm oil biodiesel with lignocellulosic biofuel (ethyl levulinate,dibutyl ether,dipentyl ether,1-propanol,1-butanol,1-pentanol and 1-hexanol). the prediction accuracy is evaluated using the average absolute relative deviation (aard) between the experimental data and the predicted values. the predictions for b5-ethyl levulinate are close to the data (aard = 1.8% for both unifac type models) even though the flash point of the mixture is below the flash point of individual components. on the other hand,the aard values obtained using original unifac are 3.3% and 5.9% for b5- dibutyl ether and b5-dipentyl ether while using modified unifac (dortmund),the aard obtained are 3.6% and 6.1%,respectively. for the b5- alcohol blends,the aard values obtained for b5-1-propanol,b5-1-butanol,b5-1-pentanol and b5-1-hexanol blends are 33.3%,9.5%,5.7% and 2.6% respectively for original unifac and 34.5%,9.1%,5%. %6 and 2.2% respectively for modified unifac (dortmund). the prediction accuracy of the model is decreasing with the decrease of the carbon chain length in the alcohol. overall,the liaw model that is incorporated with either original unifac or modified unifac (dortmund) has similar prediction accuracy. liaw model using unifac type models generalized the flash point predictions for different green diesel blends. however,the prediction accuracy for b5-alcohol blends need to be improve further which will be part of the future work. © school of engineering,taylor’s university.