2022-09-23
Material selection and performance of column internals
Tower internals are an important part of cooling towers, and are the key components of cooling tower heat exchange. After years of experience in the production and installation of tower internals, it is concluded that the cooling generated by the packing reaches 60% to 70% of the cooling of the entire tower. It is also generally made of unyielding polyvinyl chloride corrugated board, with exquisite hydrophilic properties, ensuring that water forms a water film and water spots on the packing instead of water flow, strengthening the water-air exchange area, and extending the water-air exchange time. Guaranteed cooling results.
The tower internals produced by the tower internals company are characterized by light weight, high strength, good flame retardant performance, corrosion resistance, advanced design, low ventilation resistance, strong hydrophilicity, and large combat area. The selection of tower internals needs to be analyzed from multiple perspectives. There are often three representative standards, characteristics and scales for tower internals products. These are generally the most fundamental and most needed information. However, there are other information that should also be paid attention to. The following takes the inner part of the multi-faceted hollow spherical tower as an example.
It is necessary to analyze the effect of polyhedral hollow spheres as tower internals from another angle. It contains the number of piles less than the surface area, the bulk density, the cumulative weight and other parameters, but also the material produced, the structure, the resistance of the structure of the multi-faceted hollow sphere, the distribution of water, and the gas distribution performance. On the one hand, the problem that can be explained is that in the process of water treatment tower internals, the use of various materials for the tower internals can improve the quality and strength of the tower internals.
2022-09-23
The difference between structured packing and other packing
Structured packing is a packing that is arranged in a uniform geometric pattern in the tower and stacked regularly. Consists of many packing units with the same geometry. Random packing has the characteristics of a certain orderly arrangement in the process of random random packing, so the pressure drop, the flux is large, the liquid distribution is uniform, and the operation flexibility is large. However, compared with structured packing, structured packing has a series of advantages such as high efficiency, low pressure reduction, large processing capacity, uniform gas-liquid distribution, small liquid holding capacity, insignificant expansion effect, and large operation flexibility. Structured packing and random packing have different prices and different uses. If the price is not considered, the parameters of structured packing are better than random packing.
However, the materials of other packings and structured packings are the same, namely: ceramics, metals, plastics.
According to different usages in different application fields, they are mainly used as tower fillers in petrochemical, chemical, fertilizer and other industries, and placed in reaction towers, such as desulfurization towers, drying towers, cooling towers, etc. Random packing and structured packing do not have to be used together. See how the packing is designed during design. There are random packing towers and structured packing towers. Random packing can be fixed with packing support internals during installation.
2022-09-23
Pall ring separation efficiency and high operating flexibility
Pall ring packing has the advantages of large flux, small resistance, high separation efficiency and large operating flexibility. Under the same pressure reduction, the processing capacity can be more than 50% larger than that of Raschig ring. At the same throughput, the pressure reduction can be reduced by half, and the mass transfer efficiency can be increased by about 20%. Compared with the Raschig ring, this packing has the characteristics of large production capacity, low resistance, and large operating flexibility. Under normal circumstances, the same pressure drop can be treated by 50%-100% larger than that of the Raschig ring. The west ring is 50%-70% smaller, and the tower height is also reduced. The use of the Pall ring can be about 20%-40% of the packing volume compared to the Laxi link.
The Pall ring is a great improvement on the Raschig ring. Although the outer diameter of the ring is also equal to the height, there are two rows of windows with inwardly extending tongues on the ring wall, and each layer of window holes has 5 tongues. This structure improves gas-liquid distribution and makes full use of the inner surface of the ring. Compared with Raschig rings, the processing capacity can be more than 50% larger, and the pressure is reduced by half; generally made of metal, plastic or ceramic.
Pall ring packing is divided into three materials: metal, ceramic, plastic and so on. Among them, metal materials: 304, 316, 316L, carbon steel, 201, etc. Among the plastic materials: PP, RPP, CPVC, PVDF, PVC, etc.
2022-09-23
Pall ring packing
The use of Pall ring packing can have larger surface area and void ratio, increase the uniform distribution of fluid, change the range of liquid spray density, and enhance the effect of mass transfer. Now put forward some opinions on the construction and transformation of domestic Pall ring packing:
1. In response to the national call for energy conservation and emission reduction, and reducing production costs for enterprises, the application of Pall ring packed towers will inevitably increase enterprise benefits and achieve the purpose of rational use of energy.
2. The technical feature of the Pall ring packed tower is the material and shape of the packing. When choosing Pall ring packing, attention should be paid to the choice of packing, once the material or installation of Pall ring has problems, it will greatly affect the rectification effect. The thermal stability of plastic Pall ring packing material is not good, but its corrosion resistance, small mass and excellent processing performance. Metal Pall ring packing addresses poor thermal stability properties, but is susceptible to corrosion. Ceramic Pall ring packing can solve both temperature problems and corrosion problems, but its brittleness and weight are its disadvantages. Type bulk Pall ring packing is easy to process, pack and clean, but it is difficult to control maximum wetting of the packing. The equipment investment of structured Pall ring packing suitable for most separations is much higher than that of bulk packing.
3. When installing the Pall ring packed tower, it is not only necessary to ensure the initial distribution of the liquid is uniform, but also to ensure the liquid distribution of the entire Pall ring packed tower. This problem can be solved by adding a liquid redistribution device. Good liquid distribution can increase the free cross-sectional area of gas passage, reduce gas passage resistance, increase operating flexib
2022-09-23
Advantages of structured packing
Although the geometric structure of structured packing and the arrangement in the column are different, they have in common that the gas and liquid passages and the contact mass transfer mode of the same structure are artificially specified; the porosity and the effective contact surface area are increased; the two phases are strengthened. lateral mixing; reduce wall flow and channeling phenomena, etc.
In this way, structured packing significantly overcomes the amplification effect and effectively improves the separation efficiency and throughput. It and random packing have different lengths and weaknesses, and each has its own scope of application, which together form a packing series with strong applicability and wide separation performance. In the development of the combination with the plate column, the packed column has more remarkable advantages.
Column packing is the basic element of gas-liquid contact mass transfer in packed columns. The structured packing forms numerous mass transfer units with the same structure and spatial symmetry in the whole packed tower. The structure of the unit cell determines the gas-liquid two-phase flow mode and the contact mass transfer condition. To this end, structured packings are classified according to their basic structural characteristics.
Corrugated structured packing is currently the best and most widely used structured packing. According to the structure, it can be divided into two categories: vertical corrugated type and horizontal corrugated type. The metal wire mesh corrugated packing is a disc-shaped packing composed of several parallel and in-line metal corrugated meshes. The corrugated mesh is the element that constitutes the corrugated packing of the wire mesh.
2022-09-23
Metal structured packing
Metal structured packing includes perforated plate corrugated packing, expanded mesh corrugated packing, perforated plate corrugated packing, wire mesh corrugated packing and annular corrugated packing.
Orifice corrugated packing is a structured packing assembled with holes on the surface of metal sheet and large corrugations. It has the characteristics of low resistance, uniform gas-liquid distribution, high efficiency, large flux, and insignificant amplification effect. pressure and pressurization operations.
Wire mesh corrugated packing is an important milestone in the development of structured packing. This packing is arranged by corrugated wire mesh sheets. The inclination angle of the corrugated sheets is 30° or 50°. When , the upper and lower two-person trays are staggered and stacked at 90°. It has the advantages of high efficiency, pressure drop and large flux. The products are BX and CY type, which are often used in vacuum distillation, atmospheric distillation and absorption process of difficult to separate and heat-sensitive materials.
Punctured corrugated packing is a structured packing formed by rolling a slanted metal sheet to form small punctured holes with high density and then pressing into corrugated sheets. Wire mesh corrugated packing and other properties.
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