<![CDATA[The ever-growing demand for energy has driven many parties to seek more sustainable alternative fuels, and biodiesel from palm oil is a promising candidate. However, the biodiesel production process still faces several significant challenges, particularly regarding reaction effectiveness and transesterification stability. These two issues are the primary focus of this research. This study investigated the effects of circulation operating time and circulation flow rate in a continuous circulation reactor on biodiesel characteristics. Biodiesel synthesis was performed by varying the circulation operating time (60, 80, and 100 min) and the circulation flow rate (100, 300, and 500 LPM). Here, the circulation operating time refers to the duration of each experimental run during which the reaction mixture was continuously recirculated through the reactor. It represents the reactor operating duration rather than the hydraulic residence time (HRT). The resulting biodiesel was then tested for viscosity, density, flash point, calorific value, and yield. The test results showed that the viscosity of biodiesel ranged from 4.625 to 7.098 cSt, while the density was between 0.850 to 0.871 g/cm³. The calorific value of biodiesel ranged from 9915.56 to 10862.22 cal/gram, while the yield obtained was between 63.3% and 84.2%. The highest biodiesel yield (84.2%) was obtained at an operating time of 80 min and a circulation flow rate of 100 LPM. Extending the operating time to 100 min did not further increase the biodiesel yield. The highest calorific value, 10862.22 cal/gram, was achieved at an operating time of 60 minutes with a flow rate of 300 LPM. Overall, the continuous circulation reactor has good potential to increase the effectiveness of biodiesel synthesis from palm oil. Overall, the continuous circulation reactor demonstrated good potential for biodiesel production from palm oil. Among the investigated operating conditions, the highest biodiesel yield was obtained at an operating time of 80 min and a circulation flow rate of 100 LPM.]]>
