Thermomechanical process intensification for oil extraction from orange peels.

International audienceThe study investigated the intensification and improvement of oil extraction from orange peel through a thermomechanical process: the Instantaneous Controlled Pressure Drop (briefly D.I.C process). This process involves subjecting orange peel for a short time to steam pressure, followed by an instantaneous decompression to vacuum at 50 mbar. Central composite design was used to study the combined effects of processing steam pressure (1–7 bar; which corresponds to a temperature ranging between 100°C and 162 °C respectively), processing time (0.3 – 3.7 min.) and initial moisture content of orange peel before thermomechanical oil extraction (9.8 – 60.2 % on dry material basis). The quantitative analysis, have been undertaken on oil present in orange peels, after processing. Correlation analysis of the mathematical regression model indicated that quadratic polynomial model could be employed to optimize the extraction of oil from orange peel. From response surface plots, the three variables exhibited a linear effect with the strongest effect for the processing pressure. The optimum reaction conditions selected with response surface analysis were as follows: steam processing pressure: 6.6 bar, processing time: 3.68 min, initial moisture content: 53.6 % d.m basis. Under these conditions, experimental yield of orange peel oil was close to predicted value (99 %) calculated from the polynomial response surface model equation. A kinetic study indicated that extraction performed by D.I.C process is clearly quicker than conventional steam distillation method