The invention relates to a device for purifying
formic acid solution with interval
azeotropic distillation and a method thereof. The device comprises a rectification column body, an insulating layer, a
tower pot, a heating jacket, a condenser, a phase separator and a product
storage tank, wherein, the insulating layer is arranged outside the column body, the lower end of the column body is connected with the
tower pot, the upper end is respectively connected with the condenser and the phase separator, and the phase separator is respectively connected with the condenser and the product
storage tank. The method comprises the following steps: firstly,
cyclohexane is used as entrainer, and dilute
formic acid water solution with
mass concentration being 10% is initially concentrated to 30%; then,
chlorobenzene is used as entrainer, the top of the
tower continuously produces
azeotrope of
chlorobenzene and water; when the top of the tower reaches 95 DEG C-102 DEG C, the mixture of
chlorobenzene,
formic acid and water is produced, and the
mass fraction of the formic acid is 60-70% after phase separating; at last, pressurization rectification is used, the pressure is controlled at 4atm, and the tower pot can obtain 80-85% high-concentration formic acid solution. The invention has the characteristics of reasonable process flow, simple device structure, high efficiency and low cost and is suitable for industrial
continuous operation.