Effect of Low-pressure Secondary Treatment in the Development of a Low-pressure Synthesis Process for Biodiesel

The present process can obtain biofuels rich in hydrocarbons through the decarboxylation of triglycerides under atmospheric pressure using a solid base catalyst such as magnesium oxide. In this study, the primary product obtained from decarboxylation was purified by adsorption using activated clay and hydrogenation under less than 1 MPa. The improvements in physical properties before and after treatment were clarified, and changes in contents were investigated. Activated clay treatment removed polar materials such as ketones, carboxylic acids, and oxygen-containing aromatic compounds, and color tone (gray value) was significantly improved, and changes in color tone over time were suppressed. In addition, olefins and polycyclic aromatic hydrocarbons were largely removed by the hydrogenation treatment. These processes improved the oxidative stability measured by the simple oxidation stability test method (heating temperature, air flow rate, and collected water amount are different) according to the Rancimat method of the EN standard. Therefore, these two methods of adsorption and hydrogenation allowed us to develop a low-pressure production process for high-quality biodiesel by decarboxylation of fats and oils and purification of the product.