The objective of this research was to study the optimum condition of esterified oil production from low free fatty acid of mixed crude palm oil (LMCPO) by using a response surface methodology (RSM) with esterification reaction in a batch mode. LMCPO obtained from a vacuum refining process of mixed crude palm oil (MCPO) to extract the partial FFA in oil which was used as a raw materials in a food production. Therefore, remaining FFA of 6.170 wt.% in LMCPO should be reduced to less than 1 wt.% by using esterification when required these oils to use as feedstock for producing biodiesel. After esterification process, FFA in esterified oil was studied to optimize the four independent variables of methanol (5-25 vol.%), sulfuric acid (0.5-4.5 vol.%), reaction time (5-65 min) and speed of stirrer (100-500 rpm). The results showed that the optimal condition of 25 vol.% methanol, 2 vol.% sulfuric acid, 500 rpm speed of stirrer, and 30 min reaction time at 60°C reaction temperature can decreased the FFA level to less than 0.212 wt.%. However, it was found out that the high consumptions of methanol and sulfuric acid required for reducing FFA to lowest value. Thus, the selected condition of 17.4% methanol, 1.6% sulfuric acid, 300 rpm speed of stirrer, and 35 min reaction time was chosen to save the chemical contents because this condition achieved to reduce FFA to acceptable level of 1 wt.%. For the actual experiment, FFA can be decreased to 0.212 wt.%, and 1.028 wt.% respectively. The yields of 96.67 wt.% for crude esterified oil and 94.22 wt.% for pure esterified oil were achieved based on LMCPO under the selected condition.
Continuous acid-catalyzed esterification using a 3D printed rotor–stator hydrodynamic cavitation reactor reduces free fatty acid content in mixed crude palm oil
