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Overview of tower packing: Packing and internal components of towers are commonly made of metals, plastics, and ceramics. The selection of materials is primarily based on performance and price. All components will age, wear out, and even lose their properties under chemical, mechanical, and thermal effects. Materials with excellent corrosion resistance, heat resistance, and mechanical properties can have a long service life, but they are very expensive. Therefore, when selecting filler materials, it is necessary to take into account both the performance of the materials and their cost in order to choose the appropriate ones. When selecting materials, the first thing to consider is their resistance to corrosion by the separating medium. Secondly, consider durability and resistance to deformation at the operating temperature. The third consideration is to avoid contaminating or affecting product quality. On the basis of meeting the above three requirements, a cost-effective material is finally selected through analysis and comparison. Ceramic materials (light ceramics, heavy ceramics, acid-resistant ceramics, alkali-resistant ceramics, etc.) Chemical ceramics are required not only to have good resistance to chemical corrosion, but also to be impermeable, possess high mechanical strength, as well as excellent thermal stability and resistance to sudden temperature changes. However, it is difficult to meet all these requirements simultaneously; therefore, depending on the different requirements, three types of chemical ceramics can be produced: acid-resistant ceramics, acid- and heat-resistant ceramics, and industrial ceramics. Regarding the thermal stability and resistance to rapid temperature changes of ceramics, indicators such as their thermal conductivity, linear expansion coefficient, elastic modulus, and tensile strength also need to be taken into consideration. When the thermal conductivity is high, the temperature difference between different parts of a ceramic component is small when it is heated. With a low linear expansion coefficient, the amount of deformation when the temperature changes is small. When the elastic modulus is low, for the same amount of deformation, the deformation stress is small. When the tensile strength is high, the allowable thermal deformation stress is also high, thereby giving the material better thermal stability and resistance to sudden temperature changes. Since ceramic is used as a filler, unlike in chemical equipment, its allowable operating temperature is much higher when used in this capacity, with the maximum operating temperature reaching 1200–1600°C. Apart from hydrofluoric acid and silfluoric acid, chemical ceramics can resist corrosion by almost all concentrations of inorganic acids and salts, as well as organic media. It has poor corrosion resistance to phosphoric acid, and cannot withstand the corrosion of alkalis, especially concentrated alkaline solutions. This is because the large amount of silicon dioxide (SiO2) present in ceramics reacts with alkali solutions to form silicates. Plastic materials (polyethylene, polyvinyl chloride, chlorinated polyvinyl chloride, polyvinylidene fluoride, polypropylene, polytetrafluoroethylene, etc.) are high-molecular organic substances. Due to their low density, components made of plastic are lightweight; moreover, their high toughness and low elastic modulus make them an attractive material. Due to its different polymer structures and compositions, plastic exhibits excellent resistance to chemical corrosion. However, generally speaking, plastics have poor thermal stability, with their maximum operating temperature ranging from 60 to 300°C. For thermoplastics, they can become soft when heated to a certain limit temperature ； However, thermosetting plastics cannot be softened again by heating after they have been processed and cured. The fillers are all made of thermoplastic plastics; common ones include polypropylene, which can operate within a temperature range of 10–120°C. It is resistant to most acids, bases, salts, and many organic solvents, but it is not resistant to high-concentration strong acids. Polyvinyl chloride has excellent resistance to chlor-alkali, but the temperature can only reach 60°C. Chlorinated polyvinyl chloride can withstand temperatures up to 90°C, and it exhibits excellent resistance to chlorine corrosion, especially in chlor-alkali production. Polyvinylidene fluoride can withstand temperatures up to 140°C, and it is resistant to corrosion by acids, salt solutions, aliphatic hydrocarbons, aromatic hydrocarbons, chlorinated hydrocarbons, alcohols, and halogens. Metal materials (carbon steel, aluminum, copper, low-alloy steel, stainless steel, molybdenum-titanium alloy steel, tantalum, etc.) – Metals can be used to create fillers in various geometric shapes. Due to its high strength and large elastic modulus, it allows the wall thickness of the filler to be made very thin. The metal filler does not break, making it easy to load, unload, and clean.