Biodiesel purification in one single stage using silica as adsorbent

DÉBORA MANUALE; ELIZABET GRECO; ADRIANA CLEMENTZ; GERARDO TORRES; CARLOS VERA; JUAN C. YORI

CHEMICAL ENGINEERING JOURNAL

ELSEVIER SCIENCE SA

Lugar: Amsterdam; Año: 2014

1385-8947

In this paper a simple biodiesel purification method consisting in one single stage treatment with silica as adsorbent is described. The methodology presents a solution for biodiesel refining with process water, money and time savings. The treatment is made under conditions of vacuum (0.2 bar) and temperature (65-90°C). This methodology allows the removal of the excess of methanol and water (present in the crude biodiesel and adsorbed on the adsorbent material) simultaneously with the adsorption of the impurities. Silica Trisyl 3000 adsorbs 23% of its weight when the process is performed at atmospheric pressure and nearly 235% when performed under vacuum conditions. This greatly improves the utilization of the adsorbent and reduces the cost of the process. Under these conditions, the silica behaves as a non-selective adsorbent of high capacity that is able to adsorb different types of impurities, which makes it an excellent adsorbent to purify biodiesel. On the other hand, the adsorption phenomenon is not limited to the formation of a theoretical "monolayer" of adsorbed impurities. It is more complex and involves the formation of multiple layers.