Biodiesel production using microreactor with integrated microheater through multi-objective optimization approach

Abstract

Microreactor is one of the process intensification techniques which uses reaction dimensions below millimeter size and have greater yield within lesser reaction time and a high heat transfer rate due to their high surface to volume ratio. To develop energy efficient reactors, microheater is chosen as the heating source for microreactor which consume less power than the conventional heating elements. Using response surface methodology (RSM) and artificial neural network (ANN) the effects of the biodiesel process variables was analyzed: catalyst concentration (0.5–2.5 wt.%), reaction temperature (35–55 °C), flow rate (5–25 mL/min), oil to methanol molar ratio (1:6–1:18), and power supplied to the microheater (15–35 W). To observe more than set limit, Technique for Order Performance by Similarity to Ideal Solution (TOPSIS) and VIKOR were used to evaluate the optimum conditions. Under the optimum conditions of 20 mL/min flow rate, 45 °C reaction temperature, 1.5 wt.% catalyst concentration, 1:9 oil to methanol molar ratio, and 20 W power supplied, the maximum biodiesel yield for microreactor with microheater is 91.1 %. Using ultrasonic mixing additionally for microreactor with microheater had maximum yield of 94.4 % under the optimum conditions.