What are the two options for packing a column?

• A. Structured Packing and Random Packing
• B. Bubble Cap Trays and Valve Trays
• C. Structured Packing and Tray Packing
• D. Random Packing and Plate Packing

Answer: (A)

In packed columns, the internals that promote vapor–liquid contact come in two main forms: structured packing and random packing. Structured packing uses engineered, regularly arranged elements that create uniform flow channels, giving a high surface area with predictable performance and relatively low pressure drop. Random packing uses irregular pieces (like rings or saddles) that fill the column in a chaotic arrangement, which is typically easier to install and can be cost-effective for many separations.

Tray internals, such as bubble cap trays and valve trays, are a different approach to contacting phases—they create discrete stages rather than continuous packing. Terms like “Tray Packing” aren’t standard, and “Plate Packing” isn’t a typical concept either. So the two valid packing options are structured packing and random packing.