Evaluating the performance of batch, tubular coiled and coil flow invertor reactors in biodiesel production from karanja and used cooking oil

Current research evaluates the performance of three different contacting schemes: the batch reactor, tubular coiled reactor (TCR), and coiled flow inverter (CFI). Experiments utilized a 1.5 wt. % KOH catalyst with varying methanol/oil molar ratios in both batch and continuous reactors. The TCR and CFI were tested at a 9:1 methanol/oil molar ratio with flow rates ranging from 2–10 ml/min, using Karanja oil and Used Cooking Oil. Notably, the biodiesel produced in this study met the key fuel property requirements such as kinematic viscosity, density, flash point, and calorific value according to the American Society for Testing and Materials (ASTM) biodiesel standards. The highest biodiesel yield in the batch reactor was 90.63 % at 900 RPM. The continuous flow reactors achieved an 82.52 % yield in the TCR with a diameter of 1.65 mm and a length of 4 m, and a 92.6 % yield in the U-shaped CFI at a flow rate of 8 ml/min. Notably, the highest yield for Karanja oil and used cooking oil was observed in the CFI (U-shape) compared to the TCR, CFI (L-shape), and batch reactor. This study showed an improvement in biodiesel properties by using two-stage esterification-transesterification methods.