🔍 Key Concepts

• Economizer function in a boiler system and where it is located in relation to the boiler and exhaust gas path • How acid dew point and metal surface temperature affect sulfuric acid condensation and tube corrosion • What happens to steam pressure and gas temperature when boiler pressure is raised or lowered

💭 Think About

• Think about whether you want the metal surfaces of the economizer tubes to be warmer or cooler to reduce acid condensation and corrosion when blowing tubes • Consider how each option (raising or lowering boiler pressure, changing water level, draining headers) would affect the temperature of the economizer tubes and gases at that moment • Ask which change will move tube metal temperature farther above the acid dew point, making acid corrosion less likely

✅ Before You Answer

• Identify which action will increase tube metal temperature relative to exhaust gas dew point during sootblowing • Eliminate options that mainly affect water level or mechanical aspects without significantly protecting against acid condensation • Verify in your steam plant knowledge which boiler pressure change tends to make feedwater and economizer outlet temperatures higher at a given firing rate