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Packing, a critical tower internal in chemical, petrochemical, and environmental engineering, directly impacts process efficiency and cost-effectiveness. Two primary materials dominate: plastic and metal packing. This article compares their properties, performance, and applications to aid material selection. plastic packing, often made of PP, PE, or PVDF, has low density (~0.9-2.0 g/cm³), making it lightweight and easy to install. It excels in corrosion resistance, withstanding acids, alkalis, and organic solvents, ideal for aggressive media. However, it has lower thermal conductivity (~0.2-0.5 W/m·K), limiting use in high-temperature processes (typically <100°C for PP, <150°C for PVDF). Metal packing, such as stainless steel (304/316) or aluminum, offers high density (~7-8 g/cm³), high mechanical strength, and excellent thermal conductivity (~15-200 W/m·K), enabling operation up to 300°C or higher. But it is prone to corrosion in acidic or salty environments without coatings. In performance, plastic packing often has higher specific surface area (150-500 m²/m³), enhancing mass transfer efficiency, though lower rigidity may cause higher pressure drop under high flow rates. Metal packing, with lower surface area (100-350 m²/m³), balances efficiency and pressure drop, outperforming plastic in high-capacity applications. Its robustness reduces channeling and ensures stable performance. Plastic packing is widely used in water treatment, food processing, and small-scale chemical plants, prioritizing cost and corrosion resistance. Metal packing shines in refineries, power plants, and industrial gas separation, needing high temps and durability. Cost-wise, plastic is cheaper initially (30-50% lower), but metal has longer life (5-10 vs. 3-5 years), lowering lifecycle costs. Plastic may have environmental concerns (non-biodegradable), while metal is recyclable. The choice depends on process conditions: plastic for low-cost/corrosion/low temp; metal for high temp/strength/long-term use.
