Fatty acid solvent extraction from palm oil using liquid–liquid film contactor: Mathematical model including mass transfer effects

Abstract

Free fatty acid (FFA) presence in vegetable oils (VO) promotes unwanted organoleptic characteristics. Its traditional removal is carried out by steam distillation (deodorization). However, the high temperature of this process promotes the formation of toxic components such as glycidol esters (GE) and 3-monochloropropane-1,2-diol (3-MCPD). FFA extraction by solvents is an alternative refining process at low temperatures which preserves natural phytonutrients that are thermically destroyed or distilled in deodorization. In this work, a model to predict continuous co-current FFA extraction with a liquid–liquid film contactor (LLFC) using ethanol as a solvent at low temperature (<80 °C) was developed and experimentally validated. This model includes the prediction of the FFA mass transfer from the oil-rich phase to the interface. Experimental validation also assessed the effects of flow rate (0.5–1.5 kg/h), ethanol to oil mass flow rate (1–2), FFA initial concentration (2–4 wt.%), and LLFC stages employed on FFA removal. At the best operational conditions experimentally evaluated, it was possible to reduce the FFA content from 4 wt.% to 0.08 wt.%. The mathematical model shows an approximate description of the LLFC behavior and mass transfer effects that can be used for the scale-up of the technology.