Types, characteristics and uses of structured packing

Structured packing is a packing that is arranged in a certain geometric configuration and stacked neatly. There are many types of structured packing, which can be divided into grid packing, corrugated packing, etc. according to their geometric structure.
(1) Grid packing: It is composed of strip units combined in a certain rule and has a variety of structural forms. The earliest grid packing used in industry is wooden grid packing. The more commonly used ones are Glidge grid packing, mesh grid packing, honeycomb grid packing, etc., among which Glidge grid packing is the most representative.
Grid packing has a low specific surface area and is mainly used in occasions requiring small pressure drop, large load and anti-blocking.
(2) Corrugated packing: The vast majority of structured packing used in industry is corrugated packing, which is a disc-shaped packing composed of many corrugated thin plates. The inclination angle of the corrugation to the tower axis is 30° and 45°. When assembled, the adjacent two corrugated plates are stacked in opposite directions. Each disc packing is installed vertically in the tower, and the adjacent two disc packings are staggered at 90°.
According to the structure, corrugated packing can be divided into two categories: mesh corrugated packing and plate corrugated packing. Its materials can be divided into metal, plastic and ceramic.
Metal mesh corrugated packing is the main form of mesh corrugated packing, which is made of metal mesh. Metal mesh corrugated packing has low pressure drop and high separation efficiency. It is particularly suitable for precision distillation and vacuum distillation equipment, and provides an effective means for the distillation of difficult-to-separate systems and heat-sensitive systems. Despite its high cost, it is still widely used due to its excellent performance.
Metal plate corrugated packing is a main form of plate corrugated packing. The corrugated plate of this packing is punched with many small holes of about f5mm, which can play a role in roughly distributing the liquid on the plate and strengthening the lateral mixing. The corrugated plate is rolled into fine grooves, which can play a role in finely distributing the liquid on the plate and enhancing the surface wetting performance. Metal perforated plate corrugated packing has high strength and strong corrosion resistance, and is particularly suitable for large-diameter towers and occasions with large gas-liquid loads.
Metal rolled perforated plate corrugated packing is another representative plate corrugated packing. The main difference between it and metal perforated plate corrugated packing is that the plate surface is not punched, but punctured. The plate is rolled to produce dense small puncture holes with a diameter of 0.4 to 0.5 mm. Its separation ability is similar to that of mesh corrugated packing, but its anti-blocking ability is stronger than that of mesh corrugated packing, and it is cheaper and more widely used.
The advantages of corrugated packing are compact structure, small resistance, high mass transfer efficiency, large processing capacity, and large specific surface area (commonly used are 125, 150, 250, 350, 500, 700, etc.). The disadvantages of corrugated packing are that it is not suitable for handling materials with high viscosity, easy to aggregate or with suspended matter, and it is difficult to load and unload and clean, and the cost is high.