Authors: Mehmet BİLGİN, İ. Metin HASDEMİR, Ahmet AYDIN, Umur DRAMUR
Abstract: In this study, the mass transfer parameters were investigated in the liquid extraction process, which is the main step of producing caffeine from tea residue, in a packed brosilicate glass column, 5.86 cm in diameter, 132 cm in height, filled by 10x10 mm glass Raschig rings. Because chloroform was used as a solvent in the extraction process, the equilibrium distribution of the water-caffeine-chloroform ternary system were determined at room temperature. By using various solvent/raffinate (S/R) volumetric feed ratios and employing phase reversal in the column, the mass transfer coefficients, the number of transfer units, the height of transfer units, the number of theoretical stages and the height equivalents to a theoretical stage were calculated and thus the most suitable S/R value was determined. The number of theoretical stages were found with the equations proposed by Treybal, Planowski and Alders, and the stages were compared with each other. The optimum mass transfer parameters were reached when the S/R ratio was 0.933 and chloroform was used as the continuous medium.
Keywords: Caffeine, Mass Transfer, Liquid Extraction, Packed Column
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