As shown in the illustration, the main...

🔍 Key Concepts

• Trace the flow path of steam and water through the waste‑heat system, from the exhaust gas economizer to the turbine and then to the condenser/hotwell. • Identify what pieces of equipment the line containing valve 6 connects (look at the arrows and where that piping returns). • Think about why a system would need a bypass or recirculating line when load on the turbo‑generator is very low or zero.

💭 Think About

• Follow the arrows from the economizer and the drum/superheater and see whether valve 6 is on a steam line, a condensate line, or a feedwater line—what does that tell you about its job? • Ask yourself: in which of the four answer choices would a valve in that exact location be most useful to protect equipment or maintain proper flow when operating conditions change? • Consider what happens to feedwater/condensate flow and equipment temperatures when the turbo‑generator is idling or at very low load—what control function would you want from valve 6 in that situation?

✅ Before You Answer

• Confirm whether valve 6 is upstream or downstream of the turbine and whether it returns to the hotwell/condenser or back toward the boiler/economizer. • Verify if valve 6 is on a line that could reasonably change the flow rate through the economizer or feed system when the generator load changes. • Make sure the function you pick matches a valve whose normal operation would occur mainly at low load or startup/shutdown, not during normal full‑load running.

As shown in the illustration, the main function of the valve labeled "6" would be to ________. Illustration MO-0128

raise vacuum during startup

relieve excess steam pressure when the turbo-generator is idling

provide make-up feedwater for the hotwell

recirculate feedwater at low loads

🔍 Key Concepts

💭 Think About

✅ Before You Answer