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Main Steam Cycle Let the fun begin….

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Presentation on theme: "Main Steam Cycle Let the fun begin…."— Presentation transcript:

1 Main Steam Cycle Let the fun begin…

2 Introduction Parts of the Main Steam Cycle Four Phases of the cycle
Definitions of each phase Components involved with phases Press-temp relationships

3 Parts of Main Steam Cycle
Steam Generator (nuclear) or Boiler (conventional) Turbines Condenser Main Condensate Pumps Deaerating Feed Tank / Reserve Feed Tanks Main Feed Pumps

4 Main Steam Cycle

5 Background Cycle used is a Rankine cycle P-v and T-s Diagrams
Trace the points of cycle Provide graphical understanding of cycle Four phases of cycle Conventional vs. Nuclear

6 Rankine Cycle T-s Diagram P-v Diagram
1-2: Feed Phase (DQ=0, DS=0), Win 2-3: Generation Phase (DP=0), Qin 3-4: Expansion Phase (DQ=0, DS=0), Wout 4-1: Condensation Phase (DP=0), Qout

7 Generation Phase - Conventional
Boiler (1200 # steam) Fuel burned to produce heat -> transferred to water which boils to steam Steam collects in steam drum (saturated) Superheater Increase temp of steam and dries steam Three reasons for superheating? Minimize erosion (dry steam better for blading) Minimize corrosion (less chemicals entrained) Maximize DT (Carnot efficiency)

8 Boiler and Superheater

9 Generation Phase - Nuclear
Reactor (Rx) Plant Fission in Rx core transforms nuclear energy to thermal energy Steam Generator Water Space U-tubes Steam Space Moisture Separators

10 Reactor Plant

11 Expansion Phase Steam travels down main steam piping
Turbines convert thermal energy -> mechanical energy (nozzles) and then work (blading) -> turn rotor/shaft Pressure drops as steam goes through Work performed on turbine blading Main Engines (ME) -> propulsion Ship’s Service Turbine Generators (SSTG) -> electricity


13 Condensation Vacuum 26-29” Hg
Air Ejectors - use 150# steam to establish initial vacuum and remove air Maintained by condensation volume of water << volume of steam -> contraction Why vacuum? Ease of steam recovery (“pulls” steam into MC) More work out of turbines (larger DP and DT) Ease of conversion to water

14 Condensation Main Condenser
Large, indirect, cross-flow, shell-and-tube HX Seawater used to condense steam Hotwell - holding area for condensate water at F (lowest temp in cycle) Main Condensate Pumps - send condensate to the DFT at psi (suction side is lowest pressure in cycle)

15 Main Condenser

16 Feed Phase Deaerating Feed Tank (DFT) Main Feed Pump
Direct-type HX (Aux Steam used) Purposes preheats feed storage/surge volume removes dissolved oxygen to minimize corrosion FYI: RFT’s often used instead Main Feed Pump Supplies feed water to Steam Generator (must be high pressure to overcome pressure)

17 Deaerating Feed Tank

18 Putting It All Together

19 Your Drawing Boiler/Steam Generator Superheater Turbine Condenser
Main Condensate Pumps Main Feed Pumps DFT/RFT Economizer

20 Questions?

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