Aerogel is a super thermal insulation material with a three-dimensional nano-porous structure and a porosity of over 95%. Due to its extremely low thermal conductivity, it is widely used in industrial thermal insulation, aerospace, new energy and other fields. The core preparation process of aerogel includes three stages: sol-gel forming, solvent replacement and drying shaping. Among them, the drying process is the key to determining the pore structure, thermal insulation performance and production cost of materials. At present, the mainstream preparation technologies in the industry are divided into four categories: supercritical drying, atmospheric pressure drying, freeze drying and vacuum drying.

Supercritical drying is a classic technology for preparing high-performance aerogels, with carbon dioxide supercritical drying being the most widely used. This technology eliminates the gas-liquid interfacial tension of solvents through high pressure and high temperature, completely avoiding the collapse of the gel skeleton caused by capillary force and retaining the complete porous structure to the greatest extent. The finished products feature uniform pores, excellent thermal insulation and strong structural stability, which are mostly applied in harsh scenarios such as aerospace and high-end industrial equipment. However, it requires large equipment investment and adopts intermittent production mode with high energy consumption and cost, making it difficult for large-scale popularization.

In general, supercritical drying focuses on high performance, atmospheric pressure drying adapts to large-scale mass production, and freeze drying specializes in special materials. With the upgrading of industrial energy-saving demands, the low-cost and high-performance atmospheric pressure modified drying technology has become the core trend of aerogel industrialization.