ANS:A - Spray dryer

A spray dryer is a type of dryer used to convert a liquid or slurry into dried particles or powders. It is particularly well-suited for producing powders with a fine and consistent particle size distribution. Here's how a spray dryer typically works:

1. Atomization: The liquid or slurry feedstock is atomized into small droplets. This can be achieved using various methods such as pressure nozzles, rotary atomizers, or centrifugal atomizers. The atomization process breaks the liquid into tiny droplets, increasing the surface area available for evaporation.
2. Drying Chamber: The atomized droplets are introduced into a drying chamber. Inside the drying chamber, hot air is introduced, creating a high-temperature environment. As the droplets fall through the chamber, the hot air quickly evaporates the moisture from the droplets, leaving behind dried particles or powders.
3. Particle Collection: The dried particles or powders are collected at the bottom of the drying chamber. The hot air and any remaining moisture are typically vented out of the drying chamber. The dried product can then be collected, packaged, or further processed as needed.

Spray dryers offer several advantages for drying liquid or slurry feedstocks:

• Rapid Drying: The atomization process creates a large surface area for evaporation, allowing for rapid drying of the feedstock.
• Controlled Particle Size: The particle size of the dried product can be controlled by adjusting parameters such as feedstock composition, atomization technique, and drying conditions.
• High Efficiency: Spray dryers can achieve high drying efficiencies, making them suitable for large-scale production.
• Versatility: Spray dryers can be used with a wide range of feedstocks, including food products, pharmaceuticals, ceramics, and chemicals.

Overall, spray dryers are widely used in various industries for their ability to efficiently convert liquid or slurry feedstocks into dried particles or powders with desired properties.