Optimization of mechanical oil extraction from Jatropha curcas L. kernel using response surface method

•We model expression of oil from Jatropha kernel using a quadratic polynomial model.•We examine applied pressure, pressing temperature and moisture content to oil recovery.•Increasing applied pressure and pressing temperature increase oil recovery, while moisture content has an optimum value.•We analyses the oil expressed from two variety of Jatropha kernel which pressed at optimum condition. The qualities are varied between two varieties especially on phosphorus and metal contents.

Extraction of oil from Jatropha curcas L. kernel was investigated using a lab-scale hydraulic press. A face centered composite design of experiments was employed to study and optimize the effect of applied pressure, pressing temperature and moisture content on oil recovery. A quadratic polynomial model was generated to predict oil recovery and was found to cover 98% of the range for the factors studied, namely 10–20 MPa applied pressure, 60–90 °C pressing temperature and 3–5% (w.b.) moisture content. Among the process parameters studied, pressing temperature had the most significant effect on the recovery followed by applied pressure and quadratic of moisture content. Model validation experiments show good correspondence between actual and predicted values. The optimal extraction condition for oil yield within the experimental range of the variables researched was at 19 MPa applied pressure, 90 °C pressing temperature, and 3.8% (w.b.) moisture content. At this condition, the yield of oil was predicted to be 87.8%.

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