🔍 Key Concepts

• Heat transfer efficiency in submerged tube evaporators • Effect of scale buildup on heating surfaces and distillate output • Difference between mechanical leaks (brine leaks) and thermal performance problems

💭 Think About

• What condition would cause the evaporator to need more temperature difference to produce the same amount of distillate? • If maximum steam pressure is already being used, what kind of problem would reduce the effectiveness of that steam on the water side? • Which options describe a symptom cause (root problem in heat transfer) versus an operating adjustment (something you would normally tweak)?

✅ Before You Answer

• Check which choice directly affects overall heat transfer coefficient (U) of the tubes. • Identify which option would typically cause a gradual loss of capacity rather than a sudden failure. • Eliminate any choice that would normally be corrected by operational control rather than indicating a physical problem in the evaporator.