Supercritical fluid drying device and gel drying method

The invention provides a supercritical fluid drying device and a gel drying method. The supercritical fluid drying device comprises a fluid circulation storage tank, a circulation compressor, a drying unit, a separation unit, an expansion machine and a heating medium storage tank. A feed port of the circulating compressor is communicated with the fluid circulating storage tank, and the circulating compressor is provided with a first heat exchanger; a fluid inlet of the drying unit communicates with a discharge port of the circulating compressor, and the drying unit is used for drying materials; a fluid inlet of the separation unit is communicated with a fluid outlet of the drying unit, and the separation unit is used for separating a solvent in the fluid from the fluid; the expansion machine is arranged on a communicating pipeline between the fluid outlet of the drying unit and the fluid inlet of the separating unit; a first heat exchanger inlet of the circulating compressor communicates with the heating medi