Mechanical Continuous Oil Expression from Oilseeds: A Review

The oil extraction by mechanical pressing is the most common method for continuous treatment of oleaginous seeds without solvent. Different types of presses can be used depending on the purpose (expeller, expander, and twin-screw extruder) and on the capacity range (3 kg h−1 to 150 t day−1). At the laboratory scale, many authors have highlighted the effect of operating parameters (screw rotation speed, temperature, and back pressure) and raw material (seed species, variety, water content, and pre-treatment) on process performance (oil yield and press capacity). For a given species, the main factors influencing the process are the pressure, temperature, and moisture content. The design of models mathematically describing the operation of continuous press allows to predict the behavior and performance of various presses.