Subtopic: Concentration and drying of liquid foods – evaporators, tray, drum and spray dryers
Question Statement:
Which of the following operational advantages are associated with multiple-effect evaporators compared to single-effect evaporators?
Options:
(A) Significantly higher steam economy (kg vapor evaporated per kg live steam)
(B) Lower live boiler steam consumption for identical water removal capacity
(C) Lower initial capital equipment cost for identical heat transfer area
(D) Utilization of vapor from preceding effect as heating medium for subsequent effect
Answer Key:
A, B, D
Step-by-Step Solution & Explanation
- A, B, and D are correct: Multiple-effect evaporators reuse latent heat of secondary vapor at progressively lower pressures, multiplying steam economy.
- C is incorrect: Multiple effects require multiple evaporator bodies, condenser pumps, and intricate instrumentation, substantially increasing initial capital expenditure.