1. Recovery of Residual Oil Wim Mulder, Paulien Harmsen, Patrick Carre Sustoil, Foggia 24 April 2009

2. Introduction Residual oil recovery dependent on oil content of starting material and cake Oil recovery methods Rapeseed and sunflower: 40-50% oil Olive: 20% oil and 50% water Methods nowadays used Potential new techniques Scientific literature Rapeseed and sunflower Flaking, pretreatment, pressing, solvent extraction

3. Oil recovery Flaking Increase surface/improve heat transfer Improve oil availability Hydrolysis can occur (enzymes) Pretreatment Pressing not efficient without heat treatment Cooking Oil in cake by cold pressing rapeseed: 13.3% Oil in cake after intense cooking of rapeseed: 7.7% Cooking decreases feed value due to protein denaturation Removal of water increases oil yield Microwave Pulsed electric field Enzymatic pretreatment

4. Oil recovery; pressing and related processes Screw pressing Continuous screw presses (expellers) Cold pressing of rapeseed and sunflower not possible Single pressing: oil content of rapeseed and sunflower cake 10% Pre-pressing: cakes with 15-18% oil Residual oil removed by hexane: sunflower cakes with 2% oil and rapeseed with 3.5% oil Extrusion Alternative process giving good oil quality 90% yield by using acidic alcohol

5. Oil recovery; pressing and related processes Gas assisted mechanical expressing (GAME) CO 2 supercritical above 31°C and 73 bar Dissolution of CO 2 in oil Pressing efficiency increases Main goal to develop continuous process Novel process developed at A&F Oil extracted with CO 2

6. Oil recovery; solvent extraction Organic solvents (hexane, petroleum ether) Solvent recovery Hazardous solvents Supercritical fluids High-value products Few commercial application for commodity oils Aqueous extractions Less effective in achieving high oil yield Using enzymes improves oil extraction

7. Olives Different treatment compared to rapeseed and sunflower seed By products Olive leaves Olive cake Fuel in mill Fermentation Valuable products Olive mill waste water Stones, pulp, molasses Low residual oil content

8. Conclusions residual oil recovery Residual oil recovery Little is know about relation between process and properties of (by)products Efficiency of oil extraction process Dependent of substrate (rapeseed, sunflower, olive) Gas assisted mechanical expression process (GAME) High oil recovery without solvent extraction Mild process: recovery of other products (proteins etc) Continues process needed Novel supercritical extrusion-extraction Enzymatic extraction has potential

9. Remarks/questions © Wageningen UR