🔍 Key Concepts

• Low-pressure distilling plant operation and purpose • Effect of vacuum level on boiling temperature of water • Relationship between vacuum, temperature, scale formation, and capacity

💭 Think About

• How does decreasing the vacuum (i.e., poorer vacuum) change the boiling temperature inside the evaporator? Higher or lower? • If the boiling temperature goes up or down, what happens to the tendency for scale (salts) to deposit on heating surfaces? • How would operating at less than designed vacuum affect how much fresh water the plant can produce over time?

✅ Before You Answer

• Be clear that less than designed vacuum means a weaker vacuum (pressure inside is higher). • Connect boiling temperature change to both heat level in the evaporator and scale formation tendency. • Consider whether a plant running under off-design vacuum will have more or less capacity than at its optimal design point.