Power Cycle Analysis with Regenerative Feedwater Heating
You have been given (1) the specification sheet for a vapour power plant with a steam turbine, and (2) the heat flow diagram for the power plant, including regenerative feedwater heating system.
Analyze this system using the thermo-fluids concepts developed in this course to determine the following:
1. Provide a simplified schematic diagram of the power plant, including labels for each term you use in your analysis (i.e., ?turbine, hFW1, ?out)
2. ?out (in Btu/s) for each of the five turbine stages illustrated on the diagram
3. Qin (in Btu/s) for each of the four stages of regenerative feedwater heating (i.e., how much enthalpy is added to the feedwater at each of the heating stages?)
4. ?in (in Btu/s) to the boiler feed pumps
5. Thermal efficiency of the power plant as illustrated (with regenerative feedwater heating)
6. ?out (in Btu/s) for the entire turbine if there were no regenerative feedwater heating system (i.e., if no steam was removed from the turbine)
7. Thermal efficiency of the power plant if there were no regenerative feedwater heating system 8. Sketch the cycle with regenerative heating on a T-s diagram with each process clearly labeled (ie,
“turbine”, “RG1”, “RG2”, “pump”, etc.). Include a vapor dome.
? Provide clear labels and mass balances for each mass flow calculated
? For each device (turbine, pump, boiler) analyzed, state model assumptions and provide an energy balance
? Make your solutions clear and easy to follow (I will be putting in minimal effort to interpret messy or disorganized work)
Notes:
• Use system data given for normal operation at a turbine power output of 16 MW (i.e. 16,000 kW)
• “Heat content” values in the heat flow diagram represent specific enthalpy (h)
• “Heat consumption” values in spec sheet represent rate of heat flow into the boiler per kW of power produced (i.e., units are in BTU/(kw*hr))
• Feedwater (i.e., fluid flowing from the condenser to the boiler) can be assumed to be liquid at all stages
• Turbine and pump operation can be assumed to be adiabatic and internally reversible
• Changes in kinetic and potential energy can be ignored
• To calculate pump work, assume water pressure at the pump inlet is at atmospheric pressure (1 atm), and pressure at the pump outlet is the same as at the turbine inlet
• “Back pressure” means pressure at the outlet of the turbine (i.e, inlet of the condenser, or “condensation pressure”)
• Assume a fluid quality of x = 0.9 at the turbine outlet
• Data for “condensate” can be ignored (i.e, use data for “steam to condensate”) on far right side of heat flow diagram
