Ceramic fiber is a high-quality refractory and insulating material, designed for use in high-temperature environments. While traditionally used in thermal power plants for insulating steam turbine casings and boiler walls, its application has expanded. Today, for insulation layers exceeding 400°C, ceramic fiber products are often the material of choice for the inner layer.
(1) Application in Steam Turbine Insulation
Steam turbine casing surfaces can reach temperatures of up to 550°C, making ceramic fiber a frequent choice. The insulation thickness is typically 200mm for the upper casing and 250mm for the lower casing. The installation involves an adhesive application method, fixed with mesh in the middle, and finished with a wire mesh-reinforced surface coating.
(2) Application in Boiler Wall Insulation
Boiler wall insulation typically has a thickness of 180-200mm, with hot-face temperatures around 450°C. Therefore, the inner layer often consists of a 40-50mm ceramic fiber blanket, supplemented by two or three outer layers of mineral wool or foamed asbestos products.
(3) The Role of Ceramic Fiber Cotton
Ceramic fiber cotton is primarily used as a filling material for insulation in areas such as boiler buckstays, expansion joints, and for sealing and leak-stopping.
(4) Application in High-Temperature Pipeline Insulation
For high-temperature pipelines like main steam and reheat steam lines (both hot and cold sections), composite structures centered around ceramic fiber are increasingly replacing some or all of the traditional calcium silicate products.
Five Composite Insulation Structures for High-Temperature Pipes:
a. Ceramic Fiber + Rock Wool Structure: An inner layer of ceramic fiber blanket with an outer layer of rock wool, forming a total composite thickness of 180-200mm.
b. Ceramic Fiber + Calcium Silicate Structure: An inner layer of ceramic fiber blanket with an outer layer of calcium silicate pipe shell, with a total thickness of 180mm.
c. Ceramic Fiber + Foamed Asbestos Structure: An inner layer of ceramic fiber blanket with an outer layer of foamed asbestos, forming a total composite thickness of 180-200mm.
d. Ceramic Fiber + Fiberglass Structure: An inner layer of ceramic fiber blanket with an outer layer of fiberglass products, with a total insulation thickness of 180mm.
e. All-Ceramic-Fiber Pipe Shell: A structure entirely made of ceramic fiber, with a total thickness of 160-180mm, typically applied in two layers.
In summary, for insulating high-temperature main steam and reheat steam pipelines, alongside calcium silicate products, the five composite structures listed above are commonly used. All five utilize aluminum silicate fiber (ceramic fiber) blanket or pipe shell as the critical inner layer.
