Silicon carbide ceramic has high strength, high thermal conductivity, wear resistance and comprehensive resistance to acid and alkali corrosion, and is recognized as the "dream" heat transfer material in the field of chemical corrosion protection. Compared with traditional graphite, fluoroplastics, precious metals, glass-lined and other heat exchange materials, its heat exchange efficiency and service life have obvious competitive advantages, especially in some composite strong acid environments, its super corrosion resistance is even more It is irreplaceable and has a broad application prospect in the fields of fine chemicals, pharmaceuticals, steel, light industry, etc., and plays an increasingly important role in promoting the upgrading of equipment and processes in related fields.
However, for silicon carbide ceramics to be used in the field of heat exchange, the preparation of large-sized and complex-shaped components is particularly critical. For example, for a shell and tube heat exchanger, it is not complicated to sound that the silicon carbide raw material is made into a circular thin tube in the heat exchanger. However, for each "long height" and "long thin" of the circular tube, the The difficulty of production becomes a geometric progression. The wall thickness of the heat exchange tube is usually less than 2.0mm and the length is more than 1500mm in order to show good heat exchange capacity. Pipes of this specification are usually prepared by extrusion molding. Due to the particularity of the silicon carbide raw material powder, the challenge lies in how to prepare a plastic highly dispersed mud system, and at the same time, how to improve the uniformity and execution of the microstructure of the extruded tube element base while guaranteeing the element embryo strength And to reduce the defects of prime embryos as much as possible. Similarly, in high-temperature sintering, high-density and deformation-free sintering of long tubes and thin-walled silicon carbide tubes is also critical.
Silicon carbide heat exchange tube
For plate and block-hole heat exchangers, the minimum groove width of the heat exchange plate is usually less than 2.0mm, especially the fine processing of its complex heat exchange channels is very important. No large stress is generated during processing, which guarantees the stress and deformation of high temperature sintering. In block holes, the minimum distance between vertical and side holes is usually less than 2.0mm, and the hole depth is usually greater than 300mm. For the precision processing of such components, it also faces very great challenges.