🔍 Key Concepts

• Uncontrolled interdeck superheater – how its outlet temperature depends on boiler firing rate and steam flow rather than active temperature control • Effect of feedwater temperature on steam drum conditions (drum pressure, evaporation rate, steam flow through the superheater) • Heat transfer in a gas‑fired convection superheater when steam flow or gas temperature changes

💭 Think About

• If you lower the feedwater temperature entering the drum, what happens to the overall heat balance in the boiler for the same firing rate? Does the furnace gas temperature or required heat input to reach saturation change? • How does a change in steam flow through an uncontrolled superheater affect the outlet steam temperature: does higher flow usually increase or decrease superheat temperature, and why? • Think about the immediate effect versus the longer‑term steady state effect: does the superheater metal and gas side temperature change quickly or slowly compared with steam flow changes?

✅ Before You Answer

• Be clear on what uncontrolled means: there is no attemperator or control valve actively holding outlet temperature constant • Decide whether a colder feedwater causes more or less steam flow through the superheater at a given firing rate • Consider both transient (momentary) response and steady‑state behavior before choosing between a purely rise, purely fall, or rise‑then‑fall option