Biodiesel continuous esterification process experimental study and equipment design

Biodiesel is a particularly attractive renewable fuel because it can be used in existing engines, it is environmentally friendly and it is readily synthesized from animal fats and vegetable oils. Waste oil combined with heterogeneous catalysts offers exciting possibilities for improving the economics of biodiesel synthesis. The effects of methanol influx rate, reaction temperature, catalysis dosage and operation approaches on pre-esterification deacidification of trap grease were studied in a laboratory with solid acid catalysts. The results showed the maximum acid value reduction efficiency (96.73%) was obtained, and the acid value decreased sharply (from 120 to 3.92 mgKOH g⁻¹) at a methanol influx rate of 0.825 mL/m in, a reaction temperature of 115 °C, a catalysis dosage of 2.5%, and a reaction time of 2 h using 50 g of oil. An acid value of 0.89 mgKOH g⁻¹ and an esterification rate of 99.26% were obtained. When the operational approach was changed to a methanol influx of 1.32 mL/min (methanol to oil molar ratio 6: 1), a reaction time of 30 min under pressure, the methanol influx rate changed to 0.825 mL/min, and then, coupled methanol recovered and purified immediately at atmospheric pressure. A continuous esterification deacidification equipment that is suitable for factory pretreatment deacidification of biodiesel produced from trap grease with a high acid value was designed according to laboratory experiments.