Preparation of Biodiesel from the Continuous Flow of Methanol and Circulating Esterification

With fatty acid as raw material, using the two-step method, first, we use concentrated H₂SO₄ as a catalyst for esterification of fatty acid and methanol to reduce AV (acid value), and then we added methanol into the peristaltic pump to make its AV drop to below 1 mg KOH /g oil. The best condition of first stage: the temperature is 65±2°C, the catalyst dosage is 1%, the methanol to fatty acid ratio is 80%, and reaction time is 1h. The best condition of second stage: temperature is 100±5°C, the methanol flow rate 1mL/min, and the reaction time is 2h. The final biodiesel esterification ratio is 99.52%. This method has many advantages, such as it can reduce the reaction time, improve esterification ratio, reduce AV in a short time, and the technology is so simple that there is no by-products, so we can save the cost and reduce the investment.