Study On Extraction Of Crimson Glory Rose Essential Oil From Crimson Glory Rose Concrete By Supercritical Carbon Dioxide

As a recently developed separation technology, the unique advantage of supercritical fluids extraction was discussed systematically, comparing with the traditional separation methods. By the experiment of supercritical carbon dioxide extraction of crimson glory rose essential oil from crimson glory rose concrete, the influence of process conditions on the essential oil yield and quality was studied systematically. The optimal process conditions were proposed, the mathematical modeling and simulation of the extraction process was performed according to the mass transfer mechanisms, the reliability of the model was also tested by different operation conditions.A Single-step extraction and two-step separation procedure was performed in the experiment, the extraction/fractionation process evolution and its optimization were monitored by performing systematic GC analysis of the products. The optimum extraction condition, with extract pressure at 9.OMPa, extract temperature at 400CC, was obtained according to the yield and quality of the volatile oil; the optimum fractionation condition for the first separation step, at 8 .OMPa and 50C, was acquired based on the weights of waxes; the ideal fractionation condition for the second separation step, at 5.5MPa and 300C. was obtained according to the essential oil yield and quality: at the same time, the effect of supercritical carbon dioxide flux was studied and the results showed that the optimal flux was 5.0kg/h; also, the optimum extraction time, 8.Oh, was obtained according to the oil yield and quality. At the end, a comparison between the essential oil collected under the optimum conditions and that obtained by traditional methods exactly showed the advantage of the supercritical extraction.Several hypotheses were made in the mathematical model, further more, the resistance to mass transfer was considered to be lying in the concrete layer and the supercritical flu~ stagnant layer near to the concrete surface. On the concrete surface. equilibrium between concrete and supercritical fluids applies. The concrete layer on the glass bead and the whole supercritical fluid in the extraction unit was studied respectively. Based on the hypotheses, by using Navier-Stokes equation, Fick 's first law of diffusion andTIthe mass balance, the model standing for the relation between the essential oil yield and the extraction time was obtained.The density and viscosity of the supercritical fluid, and the diffusivity of essential oil in the supercriticai fluid, were estimated from the PR-equation, Watson-Uyehara method and Catchpole-King equation respectively. By the simulation of the yield curves, the best values of the distribution coefficient of the essential oil between the two phases and the diffusivity in the concrete layer were available, the concentration profiles in the concrete layer and the extraction unit could be also predicted. Besides, the reliability of the model was tested under different extraction pressure and supercritical carbon dioxide flux. This model is not only suitable for this experiment, but also applicable for the relevant applications and their engineering expansions.