Fractionation of fatty esters and acylglycerols by liquid CO2

COTABARREN, N.; HEGEL, P.; PEREDA, S.; BOTTINI, S.

Alicante

Conferencia; X Iberoamerican Conference on Phase Equilibria and Fluid Properties for Process Desing; 2015

University of Alicante

Biodiesel is produced by transesterification of vegetable oils with methanol or ethanol, in order to obtain glycerol (a byproduct) and the biofuel, which is a mixture of fatty acid alkyl esters (FAE). New applications are being developed for this byproduct in the food/beverage as well as pharmaceutical sector. Acylglycerols (ACs) or mixtures of mono and diglycerides (MG and DG) are glycerol derivatives that are also produced as intermediate products in the transesterification of vegetable oils. MG and DG have applications as emulsifiers in the food/beverage and pharmaceutical industry. The non-catalytic supercritical alcoholysis is one the most studied alternative technologies that have been proposed to improve the conventional process of biodiesel production. In the supercritical alcohol transesterification it is possible to obtain a complete conversion of triglycerides with products containing FAE and a high concentration of ACs. These reaction products can be separated in order to obtain products of higher added value. Supercritical CO2 extraction is a green technology that is increasing gaining importance over conventional techniques to process natural substrates. In a previous work it was shown through a phase equilibrium engineering analysis that FAE and ACs can be effectively fractionated using CO2 under liquid or supercritical state. In this work, FAE and AC mixtures obtained by supercritical ethanolysis were fractionated experimentally in a modified high pressure Soxhlet apparatus by liquid-liquid (L1-L2) crosscurrent extraction using liquid CO2. A thermodynamic and mass transfer modeling, combined with reliable experimental information, is applied to study the crosscurrent extraction process.