🔍 Key Concepts

• Spray-type desuperheater/attemperator function in a main steam system • Normal source of cooling water for main steam temperature control (think: where clean, high‑pressure water is already available) • Where in the system superheated main steam flows relative to the desuperheater (upstream vs downstream of superheater)

💭 Think About

• Look at the arrows and labels in the illustration: is the steam entering the device already superheated main steam, or steam that has already been cooled? • In a typical marine boiler plant, which line (feedwater line or condensate line) operates at a pressure suitable to be sprayed directly into the main steam line? • If this device is meant to control main steam temperature, should it be installed on the outlet of the superheater or on the outlet of the desuperheater?

✅ Before You Answer

• Confirm from the illustration that steam is entering from the main steam line/superheater outlet side, not from a cooled steam line. • Check which source – feedwater vs condensate – is normally at the correct pressure and purity to inject into the main steam line for temperature control. • Make sure your chosen answer pairs a realistic water source with steam coming from the correct side of the superheater (upstream vs downstream).