Supercritical fluid drying is a new drying process. Compared with traditional drying methods such as spray drying, freeze drying, and vacuum drying, it utilizes the super-solubility of supercritical fluids to dissolve the solvent in the material to be dried. It is replaced, that is, by pressure and temperature control, the solvent reaches its own critical point during the drying process, and the supercritical transformation of the liquid phase to the gas phase is completed, thereby obtaining a dried product. The solvent may be ethanol, CO2, etc. The supercritical fluid drying process is characterized by utilizing the zero surface tension of the supercritical fluid, that is, the component exhibits a solid-liquid phase interface disappearance in the supercritical state, and accelerates the gas-liquid, gas-solid. Mass transfer, heat transfer, weakening the damage of the solid particle structure caused by the interfacial tension of the ordinary drying process, so that the dried material does not have microstructural changes due to capillary tension during the drying process, such as the common pores in freeze drying. Collapse, spray drying For thermal damage of dry powder products, supercritical drying can be used to obtain powdery products directly as spray drying, and the particle size of powdered products is generally smaller than that of spray dried products. In addition, it is also possible to complete the transformation of the wet gel to the aerogel while maintaining the gel skeleton structure, to prepare a high quality aerogel, and some other nanoporous materials.