ANS:A - raschig

The most common packing used in industrial operations is Raschig rings. Raschig rings are one of the oldest and most widely used types of random packing in industrial distillation, absorption, and scrubbing columns. They are typically cylindrical ceramic or metal rings with a diameter equal to their height. Raschig rings provide a large surface area for contact between the gas and liquid phases, facilitating mass transfer and separation processes. Their simple and robust design, along with their effectiveness in promoting good liquid distribution and gas-liquid contact, makes Raschig rings a popular choice in industrial applications. They are used in various industries, including chemical processing, petroleum refining, and environmental protection, where efficient separation and purification processes are essential.