Optimisation of viscosity and density of refined palm Oil-Melaleuca Cajuputi oil binary blends using mixture design method

The increasing demand for global energy and declining oil reserves have driven the search for alternative biofuel as fossil fuel replacement. This study proposes new blends of a light biofuel based on Melaleuca Cajuputi oil (MCO) and refined palm oil (RPO) that has lowered viscosities and densities properties as compared to neat RPO. In addition, a statistical approach using mixture design method was used in the design of experiment (DOE) to evaluate the correlation between the ratio of RPO-MCO blends on their kinematic viscosity and density properties. Based on the mixture design algorithm, a total of eight experimental runs were conducted consisting of three combinations of RPO-MCO blends, two neat oils and three replicate samples. A good fit between the developed model and the experimental data was obtained for the models of kinematic viscosity and density, with corresponding R2 values 0.9992 and 0.9998, respectively. Discrepancies in the predicted values to the experimental results were within 0.1–2.5%, validating the accuracy of the developed models. The optimal blend calculated is 32RPO68MCO which gives 5.9 mm2/s and 881.5 kg/m3 for the response values of kinematic viscosity and density, respectively. Both responses values satisfy the requirement of the ASTM D6751/EN14214 standard for biodiesel.