Question

For drying of heat sensitive materials, this particular type of dryer is used

• A. Tray dryer
• B. Vacuum dryer
• C. Tunnel dryer
• D. Drum dryer

Hint:

When working with heat-sensitive materials, opt for vacuum drying as it minimizes thermal damage by reducing the drying temperature.

Answer 1

The Correct Option is B

For heat-sensitive material, the dryer needs to work at a lower temperature, so we can check each option for that property.

1. Tray dryer: Uses hot air at atmospheric pressure - too much heat exposure.
2. Vacuum dryer: Correct - reduced pressure lowers the boiling point, so drying happens at a lower temperature, protecting heat-sensitive material.
3. Tunnel dryer: Still relies on heated air at atmospheric pressure.
4. Drum dryer: Uses direct contact heat from a hot drum, unsuitable for delicate material.

So the correct answer is Vacuum dryer.

Answer 2

Another way to settle this is to think about the typical materials each of these dryers is used for in practice, and see which use-case matches "heat-sensitive."

1. Tray dryer: Commonly used for granules and bulk drugs that can tolerate moderate heat over an extended drying time - not the go-to choice for delicate, heat-labile materials.
2. Vacuum dryer: Commonly used specifically for thermolabile drugs, natural extracts, and enzymes where high temperature would degrade the active material - this matches the scenario in the question directly.
3. Tunnel dryer: Typically used for continuous, large-scale drying of bulkier or more heat-tolerant materials moving on a conveyor.
4. Drum dryer: Typically used for viscous liquids or slurries such as milk powder or starch, where intense direct heat is acceptable or even needed.

Only one of these use-cases is built around protecting heat-sensitive material.

Hence, the correct answer is Vacuum dryer.