Upgrading of biolubricants by CO2 technology

ALDANA PIZZANO; SABRINA BELÉN RODRIGUEZ REARTES; PABLO E. HEGEL

Córdoba

Conferencia; PROSCIBA 2023; 2023

Universidad Nacional de Córdoba

In this study, we evaluate the use of liquid and supercritical CO2 for the purification of a biolubricant obtained through classical esterification of fatty acid methyl esters (FAME) with TMP at 120 ºC for a 4-hour reaction under vacuum. The product obtained is filtered at 5 ºC to isolate solids and other undesired products, and the final biolubricant is analyzed to determine its FAME content. Subsequently, we investigate the purification and upgrading of this biolubricant using liquid and supercritical CO2 as solvents. We utilize in this work a high-pressure view cell to examine the phase equilibria of the biolubricant and CO2, as well as the purification of the biolubricant through a single-stage contact. We introduce a specific mass of biolubricant (approximately 7 g) and CO2(approximately 35 g) at room temperature. The temperature of the cell is then set under stirring,and once the system reaches a stable desired temperature and pressure, we sample the systemto determine the composition of the liquid and solvent phases. Next, we perform a completeextraction of the heavy liquid phase to assess the characteristics of the final product. The resultsdemonstrate that both, liquid and supercritical CO2, can be used to extract the remaining FAMEin the biolubricant. Using liquid CO2, up to 3% of FAME can be obtained in the solvent phase,allowing for the removal of up to 80% of the initial FAME content present in the biolubricant.Conversely, supercritical CO2 (40 ºC and 150 bar) exhibits a solubility of 8 wt.%, making itpossible to remove 99% of the FAME.