Deacidification of Soybean Oil Combining Solvent Extraction and Membrane Technology

Abstract

The aim of this work was to study the removal of free fatty acids (FFAs) from soybean oil, combining solvent extraction (liquid-liquid) for the separation of FFAs from the oil and membrane technology to recover the solvent through nanofiltration (NF). Degummed soybean oil containing 1.05 ± 0.10% w/w FFAs was deacidified by extraction with ethanol. Results obtained in the experiences of FFAs extraction from oil show that the optimal operating conditions are the following: 1.8 : 1 w : w ethanol/oil ratio, 30 minutes extraction time and high speed of agitation and 30 minutes repose time after extraction at ambient temperature. As a result of these operations two phases are obtained: deacidified oil phase and ethanol phase (containing the FFAs). The oil from the first extraction is subjected to a second extraction under the same conditions, reducing the FFA concentration in oil to 0.09%. Solvent recovery from the ethanol phase is performed using nanofiltration technology with a commercially available polymeric NF membrane (NF-99-HF, Alfa Laval). From the analysis of the results we can conclude that the optimal operating conditions are pressure of 20 bar and temperature of 35°C, allowing better separation performance: permeate flux of 28.3 L/m2·h and FFA retention of 70%.

Ultrafiltration Membrane for Degumming of Crude Palm Oil-Isopropanol Mixture

“…The cake layer formation occurs due to the accumulation of the solute on the membrane surface in a cake form 32 . Hermia's model was then linearized on the basis of the n value for each model by fitting equations (6) to (9) regarding the permeate flux versus time, as presented in the following. For Complete Blocking (n = 2):…”

“…The first step in the refining process is degumming, the function of which is to remove phospholipids and mucilaginous gums. Conventional degumming methods using water and acids possess numerous drawbacks due to the high energy consumption, oil loss, loss of nutrients, and requirement for large water quantities [9][10] . The membrane-based filtration process is a promising method for refining palm oil.…”

Life cycle assessment of biodiesel in Spain: Comparing the environmental sustainability of Spanish production versus Argentinean imports

“…where FFA is the percentage of free fatty acids, which is 1.05% in degummed soybean oil (Fornasero et al, 2013) and 0.55% in degummed canola oil (Ghazani, 2012), excess is the excess of caustic, and % NaOH is the caustic concentration. Suggested caustic concentrations and excess were taken from O'Brien (2004).…”

Simultaneous improvement in solvent permeability and deacidification of soybean oil by nanofiltration

“…Our research group has been working in the area of membrane preparation and their applications in different vegetable oil treatment, among them, degumming of crude soybean oil/hexane mixture with UF membranes made from different polymeric material (PVDF), Polyethersulfone (PES), Polysulfone (PSf), Polyimide (PI) Ochoa et al 2001;Pagliero et al 2004); recovery of hexane from sunflower oil/hexane miscella using composite membranes of PVDF/PDMS and PVDF/cellulose acetate (CA) (Pagliero et al 2011); removal of free fatty acids (FFAs) and hexane recovery from soybean oil, combining liquid-liquid extraction (FFA separation) and NF membrane process (solvent recovery) (Fornasero et al 2013). More recently, our group has established that SRNF made from PVDF as support and PDMS as active dense layer have high selectivity for hexane recovery and a reasonable selectivity for FFAs separation (Firman et al 2013).…”