The heat-resistance principle of aerogel is the no convection effect, infinite baffle effect, and infinite path effect brought about by its independent structure. The thermal conductivity of aerogel is 0.012~0.024W/(m·K), which is 2~3 orders of magnitude lower than that of traditional thermal insulation materials. The principle of its thermal insulation lies in the uniform and dense nanopores and multi-level fractal channel microstructures, which can effectively prevent air convection and reduce thermal radiation and heat conduction: 1) No convection effect: aerogel pores are nanoscale, and the internal air loses the ability to flow freely; 2) Infinite baffle effect: nanoscale pores, infinite pore walls, and radiation heat transfer is reduced to a minimum; 3) Infinite path effect: heat conduction is carried out along the pore wall, and the nanoscale pore wall is infinitely long.


Compared with traditional thermal insulation materials, the thermal insulation performance of silica aerogel insulation felt is 2-8 times that of traditional materials, so the amount of aerogel used is less under the same thermal insulation effect. Taking the pipeline as an example, if a pipeline with a diameter of 150mm needs to achieve the same insulation effect, the thickness of the corresponding insulation materials, expanded perlite, calcium silicate, rock wool, and aerogel felt, are 90mm, 76mm, 64mm, and 20mm, respectively. According to the calculation of Sinopec Tahe Refining, after the atmospheric coking unit was transformed from traditional insulation materials to a combination of "silicon dioxide aerogel insulation felt + single-sided aluminum foil fiberglass cloth insulation material", the heat loss was reduced by 34.7%, and the thickness of the insulation layer was reduced by more than 50% compared with traditional insulation materials.


In addition, aerogel has the advantage of a longer service life, which is about 4 times that of traditional insulation materials. Traditional insulation materials such as rock wool and polyurethane are easy to absorb water during long-term use, which affects the insulation effect on the one hand, and on the other hand, the insulation material is unevenly distributed due to gravity after absorbing water, especially in the use scenario of pipeline insulation, which easily causes the insulation material to accumulate at the bottom of the pipeline, ultimately affecting the service life. Aerogel has excellent waterproof effect, with a hydrophobicity of more than 99%, and can maintain a stable structure and thermal insulation effect during long-term use.


Currently, commercial aerogels are usually composite products with various forms. Aerogels have disadvantages such as low strength and poor toughness, so it is necessary to improve the strength and toughness by adding reinforcements such as particles and fibers, and to improve the radiation shielding ability by adding sunscreens such as carbon black and ceramic fibers. Therefore, the aerogel products currently on sale are often made of aerogel materials and substrates. According to the product form, aerogel products can be divided into aerogel felt, aerogel paper, aerogel cloth, aerogel sheet, aerogel powder, aerogel slurry, aerogel coating, etc.