Continuous Ethyl Ester Production in a High-Performance Rotor Reactor at 3:1 Molar Ratio using Response Surface Methodology

Wuttisan Khiowthong, Prachasanti Thaiyasuit


The aim of this study was to investigate the optimal conditions for continuous ethyl ester production and to validate the values of the parameters influencing the production performance. Experiments were performed at a 3:1 ethanol-to-oil molar ratio using a high-performance rotor reactor equipped with a rotor of 27.6 AF% (holes surface per rotor surface). Response surface methodology using a 3-variable 5-level central composite design was applied to vary over the range of 2160–3840 rpm rotor speed, 0.33-1.73 wt% potassium hydroxide [KOH], and 2.32–5.68 L/min flow rate. The three-parameters identified were resultant velocity (VR), Cavitation number, and Reynolds number. Production performances were yield conversion and specific energy consumption (SEC). The regression model predicted optimal conditions of 3000 rpm rotor speed, 1.170 wt% [KOH], and 5.68 L/min flow rate with ethyl ester content (CEE) of 98.84 wt%, and the actual testing showed an average CEE of 98.11 wt% The VR of 15.732 m/s resulted in a 4449.74 Reynolds number, with a Cavitation number 0.732 showing severe cavitation and turbulence to generate a 97.98 wt% yield conversion using only 0.00459 kW-h/kg of SEC.


Biodiesel; Bumpy surface rotor reactor; Optimal conditions; Resultant velocity; Severe cavitation

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