Question

In a dairy plant, spray drying technology is used to produce whey powder. The rate of spray drying depends on

• A. Temperature of the incoming air
• B. Shape of the cyclone separator
• C. Diameter of the whey droplet
• D. Heat transfer coefficient of hot air

Hint:

In spray drying, smaller droplets and higher air temperatures speed up the drying process.

Answer 1

The Correct Option is A, C, D

Step 1: Understanding spray drying.
Spray drying involves the rapid drying of liquid materials by spraying them into a hot air stream. The rate of drying is influenced by several factors: the temperature of the incoming air, the size of the droplets, and the heat transfer coefficient of the air.

Step 2: Analyzing the options.
- (A) Correct, the temperature of the incoming air is one of the most significant factors affecting the drying rate as it determines the evaporation rate of the droplets.
- (B) Incorrect, the shape of the cyclone separator does not have a significant impact on the rate of drying.
- (C) Correct, the diameter of the whey droplet is crucial, as smaller droplets dry faster due to their larger surface area relative to volume.
- (D) Correct, the heat transfer coefficient of hot air influences the efficiency of heat exchange, which is critical in the drying process.

Step 3: Conclusion.
Thus, the correct answer is (A), (C), and (D).