Method for preparing tea polyphenols with rotating disc tower countercurrent extractor

The invention discloses a method for preparing tea polyphenols with a rotating disc tower countercurrent extractor. The method comprises the following steps: removing the impurities out of tea, leaching tea with a mixture of water and alcohol to obtain tea polyphenol leach liquor, performing rotary evaporation to remove the alcohol out of the leach liquor to obtain a tea polyphenol concentrated solution, diluting the concentrated solution with a buffer solution to obtain tea polyphenol dope; pumping the tea polyphenol dope used as the raw material and an extractant into an extraction tower in a countercurrent mode to complete the extraction process, wherein the heavy phase stands still at the tower bottom and the light phase stands still at the tower top at the end; with a buffer solution as the back-extractant, pumping the extract phase and the back-extractant into a back extraction tower in the countercurrent mode, wherein two-phase fluids fully contact with each other under the rotation of the rotating disc and the back extraction process is completed; performing vacuum drying on the back extraction phase separated by the back extraction tower to obtain pure tea polyphenols; and separating to obtain the back raffinate phase which can be used as an extractant for cyclic utilization after rinsing or rotary evaporation. By adopting the method for preparing tea polyphenols with the rotating disc tower countercurrent extractor, the continuous mass production of tea polyphenols can be realized and the high-value utilization of the low-value tea can also be realized.