Cyclic esterification method for preparing biodiesel from high-acid-value grease

A cyclic esterification method for preparing biodiesel from high-acid-value grease is provided; an esterification reaction is performed in a tank reactor without stirring, materials in the reactor are transported to the top of the reactor from a pipeline at the bottom through a circulating pump for feeding, and the materials in the reactor are subjected to a fast reaction during up-and-down circulation. The method effectively overcomes the defects of a conventional preparation technology, opens up a new process for preparing the biodiesel through esterification reaction of the high-acid-value grease, and achieves the industrialized scale production of the biodiesel.