Rabesiaka JR, Pierre HR and Razanamparany B
Essential oil extraction of Pelargonium graveolens that uses the extraction by steam distillation principle was studied at two scales: Laboratory scale and pilot scale. Firstly, a simple mathematical model was considered in order to optimize the effect of parameters that can influence the yield at the initial stage. This mathematical model is in the form of first polynomial degree with 3 variables for which the coefficient evaluation is done by multilinear regression. In order to reduce errors between calculated and experimental values, an optimal design was realized then followed by corresponding experiments to the plan. The complete factorial design 23 was used. The obtained model is as shown: Y = 2,156 - 0,183X1+0,060X2 - 0,038X3 - 0,012X1X2 +0,035X1X3 +0,037X2X3
Plant mass, extraction time and condensation output displayed interesting effect on extraction yield. Secondly, an empiric model was considered to extrapolate this result at different scales. The state of the gaseous fluid inside the conducting tube was taken into account. In order to get fluids with similar characteristics, the value of the charge loss was conserved within the two scales. Actually, the charge loss determines the balance state of the fluids in the tube. Then, this was combined with a kinetic model of first order, a law concordant well between experimental and calculated results was found.