Method for continuously purifying crude glycerine

The invention relates to a method for continuously purifying crude glycerine. A column kettle of a rectifying column is connected with not only a reboiler but also a cyclone hydraulic separator; a material inlet of the cyclone hydraulic separator is connected with the column kettle; an overflow opening of the cyclone hydraulic separator is connected with a material inlet of the reboiler. A circulating pump is arranged between the column kettle and the cyclone hydraulic separator. The crude glycerine from which light components are removed is fed into the rectifying column; a glycerine product is extracted from the top of the rectifying column; during the circulating process of a material in the column kettle from the column kettle to the cyclone hydraulic separator to the rebuilder, a concentrated salt-containing residue is continuously discharged from an underflow opening of the cyclone hydraulic separator. The temperature of the column kettle of the rectifying column is 165 to 180 DEG C, and the pressure is 0.001 to 0.002 MPa. The method for continuously purifying the crude glycerine provided by the invention is performed continuously, and is particularly suitable for industrial production. Compared with the prior art, the method is performed in conventional equipment, and special equipment is not required to be invested; the method has economic advantage compared with the prior art.