CRUDE GLYCERINE PURIFICATION BY SOLVENT EXTRACTION

MAIRA MAQUIRRIAIN; CLAUDIA A. NEYERTZ; CARLOS A. QUERINI; MARÍA LAURA PISARELLO

BRAZILIAN JOURNAL OF CHEMICAL ENGINEERING

BRAZILIAN SOC CHEMICAL ENG

Lugar: BRASIL; Año: 2021

0104-6632

Due to a large variability in the biodiesel production processes and technologies, the crude glycerine has significant variations in its composition, making it difficult to run the refining unit in which crude glycerine is upgraded to high purity glycerine. In this work, a process to removed saponifiable matter from crude glycerine (fatty acid methyl esters, free fatty acids, mono-, di-, and triglycerides) is addressed. An extraction of these impurities with different solvents is analyzed in detail. Hexane and biodiesel were chosen as the main candidates in order to be used in this process. It was found that it is necessary to add water to the crude glycerine to remove the saponifiable matter efficiently. Water increases the polarity of the phase and favors the transference of the impurities to the nonpolar phase, e.g. the hexanes. The use of FAME requires the use of higher temperature than hexanes, higher levels of water addition, and pH adjustment before the extraction. UV-vis analysis proved to be very useful in following the purification process, while FTIR carried out directly on the glycerine has not enough sensitivity to follow the extraction.