Excessive soot deposits on the heating...

🔍 Key Concepts

• Heat transfer and soot: Soot on heating surfaces acts as an insulator, changing how heat moves from the gas to the water/steam. • Stack (exhaust) temperature: What happens to gas temperature leaving the boiler if less heat is transferred into the water/steam? • Superheater vs desuperheater behavior: Understand how temperatures change when heat transfer in the boiler is impaired.

💭 Think About

• If the heating surfaces are coated with soot, does more or less heat get into the steam/water? Where does that ‘missing’ heat go? • Think about how exhaust gas temperature and steam temperatures are related: if the boiler absorbs less heat, what happens to the gas leaving the boiler? • Compare what each answer choice implies physically: which effect is the most direct symptom of poor heat transfer on heating surfaces?

✅ Before You Answer

• Be clear on what an uncontrolled interdeck superheater is (takes whatever heat the gas gives it; no active control). • Ask yourself whether fuel oil and air requirements would realistically go up or down if the boiler becomes less efficient. • Decide which temperature (stack, desuperheated steam, or superheater outlet) would show the earliest and most obvious sign of heavy soot acting as insulation.

Excessive soot deposits on the heating surfaces of a boiler uncontrolled interdeck superheater would be indicated by __________.

decreased fuel oil and air requirements

increased stack temperature

increased desuperheated steam temperature

increased superheater outlet temperature

🔍 Key Concepts

💭 Think About

✅ Before You Answer