Kinematic viscosity prediction of palm oil-methanol blends for transesterification reaction mixture

Biodiesel is an essential renewable fuel which is mostly generated from palm oil and methanol in a presence of NaOH catalyst via transesterification. The difference in physical properties of feedstocks, especially viscosity, might cause a limitation of mass transfer in a liquid phase reaction, resulting in reduction of reaction rate and biodiesel yield. It is important to predict the reaction mixture viscosity in order to determine a suitable operating condition especially when performing the biodiesel production in multifunctional reactors such as a tube-in-tube and spinning disc reactors. In this study, the experiments were carried out to determine palm oil-methanol blends viscosity using a methanol-to-oil molar ratio of 6:1 at 30–60°C. The Brookfield viscometer was applied to measure the dynamic viscosity of mixture. Moreover, four calculation models including Arrhenius model, Gambill model, Kendell and Monroe model and Linear model were used to calculate the kinematic viscosity of binary liquid mixture and compared with the experimental results. The absolute percentage error (APE) and mean absolute percentage error (MAPE) were used to compare the prediction accuracy and precision of the reaction mixture in statistics. It was found that the MAPE of 4.43% was obtained on a mass basis for prediction of the kinematic viscosity by the Gambill method. This study can be a guideline for preparation of the various feedstocks in the reaction mixture of biodiesel production. In addition, the calculation of viscosity of biodiesel feedstocks blend is beneficial to determine suitable rotational speed and temperature of the reactors for efficient biodiesel production.