packed tower tower type selection of general principles.
Tower packing is the core component of the packed tower, which provides an effective phase interface for heat and mass transfer between the two phases of gas and liquid, only the excellent performance of the tower packing and then supplemented by the ideal tower parts, is expected to constitute a technically advanced packed tower. The following situations are given priority to packed towers. In the case of a high degree of separation requirements, because some new fillers have high mass transfer efficiency, so new fillers can be used to reduce the height of the tower.
For the distillation and separation of heat-sensitive materials, as the new filler holds less liquid, the pressure drop is small, so the packed tower under vacuum operation can be preferred. With corrosive materials, packed towers can be used. Because the packed tower can be used non-metallic materials, such as ceramics, plastics, etc.. Easy to foam materials, it is appropriate to use packed tower. 2, packed tower filler selection. Geometric characteristics of the filler data mainly include specific surface area, void ratio, packing factor, etc., is to evaluate the performance of the basic parameters of the filler. ① surface area The packing surface area per unit volume of packing is called the specific surface area, expressed in a, its unit is m2/m3. the larger the specific surface area of the packing, the greater the gas-liquid transfer area provided. Therefore, the specific surface area is an important indicator to evaluate the performance of the filler. ②Vacancy rate The volume of voids in the unit volume of filler is called the void ratio, expressed as ε, and its unit is m3/m3, or expressed as %. The larger the void ratio of the filler, the greater the ability of the gas to pass and the lower the pressure. Therefore, the void ratio is another important indicator to evaluate the performance of the filler. ③Filler factor The specific surface area of the filler and the cubic ratio of the void rate, that is, a ∕ ε3, known as the packing factor, to Ф, its unit is 1/m. It indicates the fluid mechanical properties of the filler, Ф value is smaller, indicating that the smaller the resistance to flow. 3, the filler performance is usually based on efficiency, flux and pressure drop three elements to measure. Under the same operating conditions, the larger the specific surface area of the filler, the more uniform distribution of gas and liquid, the better the wetting performance of the surface, the higher the mass transfer efficiency. The larger the void ratio of the packing, the more open the structure, the higher the flux and the lower the pressure drop.
