a PPliCation in C ommerCial P roDUCtion

On the basis of the whole research, an industrial application was carried out in past years. Scale-up experiments with an 18 L column were done and the results were reported in literature [44]. In addition, a workshop (Figure 4.28) and a commercial- scale fractionation system of 350 L × 2 (Figure 4.29) were established in Kaidi Fine Chemical Industrial Co. Ltd. (Wuhan, Hubei Province, P. R. China) and the technology was industrialized with an annual process capacity of 750 t ME-DOD in the year of 2000. According to our work, three patents were applied and finally released for publication [45–47].

4.8 ConClusions

As the first step of the whole research, binary phase equilibrium data of methyl oleate + CO2 and α-tocopherol + CO2 were measured and correlated with the

Soave-Redlich-Kwong EOS and Adachi-Sugie mixing rule. According to the obtained data, the solubility and distribution coefficient were calculated. Compared 290 295 300 305 310 315 320 325 330 335 0.000 0.004 0.5 1.0 Temperature (K) Viscosity (Pa.s) Figure 4.27  Comparison between the viscosities of the fractions obtained at different pressures. ◾, Raffinate at 20 MPa; ▲, 57.1% tocopherols (fraction at 20 MPa); •, FAMEs (fraction 16 MPa). (From Fang, T., Goto, M., Wang, X., Ding, X., Geng, J., Sasaki, M. and Hirose, T.,

Figure 4.28  Tocopherol concentration workshop established in Wuhan (Kaidi Fine Chemical Industrial Co., Ltd., Hubei, P. R. China).

Figure 4.29  Supercritical CO2 fractionation system (350 L × 2) for concentrating natural tocopherols.

ME-DOD in the experimental range investigated.

Second, ternary phase equilibrium data of methyl oleate + tocopherol + CO2 were

measured and correlated. On the basis of the experimental data and correlation results, the separation factor and equilibrium line were investigated. The discussion indi- cated that lower pressures and higher temperatures lead to a higher selectivity. Also, higher content of methyl oleate in the feed improves the distribution of tocopherols in gas, resulting in decreased selectivity. More noticeably, the experimental data on the realistic system of ME-DOD + CO2 led to the formation of a separation strategy. Finally, supercritical CO2 fractionation was employed to concentrate tocopherols from ME-DOD. The initial pressure was investigated for separating FAMEs. For the following tocopherol concentration step, a final pressure of 20 MPa resulted in rela- tively high average tocopherol content (> 50%) and tocopherol recovery (about 80%). On the basis of the fundamental and separation research, an application in com- mercial production was also conducted in the past years. According to the obtained results, it can be concluded that supercritical CO2 fractionation is technically feasible

for concentrating natural tocopherols from methyl esterified DOD.

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Processing of Fish Oils