Improved Lecithin Drying with Thin Film Evaporation

Abstract: As the world population grows, there is an increased need for dried soy lecithin to support the food industries that serve the world's population. The thin film evaporator (TFE) is a proficient and scalable solution used to dry lecithin for the growing food industry. 

The TFE effectively dries the lecithin to < 1 wt% moisture, and maintains color properties, while adeptly overcoming viscosity increases created by the drying process. The TFE creates a "thin film" of wet lecithin on a heated wall by smearing the material with a high-speed rotor. This rotor induces turbulence in the film, thereby creating ideal conditions for heat and mass transfer. Exposing this agitated film to heated surface area and low process pressure, e.g., vacuum, allows moisture to be evaporated at high rates, and does not burn the lecithin. The "thin film" of lecithin, typically only a few millimeters thick, only occupies the heated surface area, which allows for a very low lecithin volume within the evaporator at any given time. The low product volume keeps residence times short (typically < 30 seconds), and provides a sanitary, easy to clean process area. 

The TFE discharges lecithin that is < 1 wt% moisture with minimal heat history, has experienced minimal color change, and is pumpable to the next stage of processing. 

The TFE, while a piece of effective lecithin drying equipment, can be used for many other applications in the fats and oils industries, such as biomass drying, surfactant devolatization, and solvent recovery. It is an excellent tool for any difficult evaporation processes, and is established, scalable, and easy to maintain solution with many potential applications in an oilseed plant.