A mathematical model for effective porosity, effective force and permeability was derived using the experimental results. A universal compression machine was used to press oil of jatropha seeds at maximum force 100 kN, pressing vessel diameter 60 mm, initial pressing height 60 mm with different compression speeds ranging from 1 to 50 mm.min–1. The analysis of variance showed significant effects of compression speed on oil yield, oil point deformation, effective porosity and time of oil flow (P < 0.05), while the compression speed effect was not significant on the maximum deformation, oil point force, effective force, flow rate of oil and permeability (P > 0.05). Oil yield decreased significantly with increasing speed hence lower driving effective force. In addition, lower effective porosity required higher effective force to drive oil flow due to lower permeability and flow rate of jatropha seeds oil. Equilibrium force between effective force and oil point force at force 100 kN was determined to be 50 kN with corresponding compression speed approximately 42.74 mm.min–1. This knowledge is important in the industrial technology of oil processing where higher pressure is needed to achieve maximum leakage of oil.
jatropha seeds, oil expression, effective force, permeability, mathematical model,
Sigalingging, R., Sumono, Herák, D.,. Kabutey A., Sigalingging, S. (2019): Influence of Porosity, Permeability and Expression Force on Oil Yield of Jatropha Seeds. Scientia Agriculturae Bohemica, 50, 56-63. DOI: 10.2478/sab-2019-0009