Molecular distillation is also known as short range distillation, molecular distillation equipment mainly has falling film type, scraping film type, centrifugal type and scraping plate four. Advantages of molecular distillation system: low operating temperature (far below the boiling point), high vacuum degree, short heating time, high separation efficiency, especially suitable for high boiling point, heat sensitive, easy oxide separation; It can effectively remove low molecular substances (deodorization), heavy molecular substances (decolorization) and impurities in the mixture. The separation process is physical separation process, which can well protect the separated substance from being polluted, especially can keep the original quality of natural extract. The separation degree is higher than that of traditional distillation and ordinary film evaporator.