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Heat Exchangers

Heat Exchangers. Standards of Conduct in Training. What are the critical steps of the task?. What are the error likely situations?. What is the worst thing that could happen?. What are the specific error prevention defenses that can be used?.

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Heat Exchangers

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  1. Heat Exchangers

  2. Standards of Conduct in Training

  3. What are the critical steps of the task? What are the error likely situations? What is the worst thing that could happen? What are the specific error prevention defenses that can be used? What actions can be taken to assure proper configuration control?

  4. COURSE TERMINAL OBJECTIVE Given a maintenance activity involving Heat Exchangers (condensers, re-heaters, heaters, etc.), describe the inspection, cleaning, repair and rework methods used at Palo Verde, in accordance with plant procedures, manufacturer’s technical manuals, and standard maintenance practices, as demonstrated by achieving a minimum score of 80% on a written exam.

  5. LESSON TERMINAL OBJECTIVE Given a maintenance operation involving heat exchangers, the Plant Mechanic will describe the theory of operation and basic construction of heat exchangers, as demonstrated by achieving a minimum score of 80% on a written examination.

  6. LESSON ENABLING OBJECTIVES EO01 State the basic theory of heat transfer. EO02 Define the three mechanisms of heat transfer. EO03 List the four (4) functions performed by heat exchangers EO04 Classify heat exchangers by their construction. EO05 Identify five (5) factors which affect heat exchanger operation.

  7. HEAT • Heat is energy in transit from one mass to another because of the temperature difference between the two. • Heat: a form of energy associated with the motion of atoms or molecules and transferred from a body at a HIGHER Temperature to one at a LOWER Temperature.

  8. Temperature • A measure of the ability to transfer heat. • Heat exchanger: Device to transfer heat from one fluid to another.

  9. Principles of Heat • Heat energy will move from a high energy state to that of a lower energy state. • The process will continue until a state of Equilibrium is reached. • Energy will flow from a “hot” material to a “cold” material.

  10. Mechanisms for heat transfer • Conduction • Convection: Natural and Forced • Radiation: The only method of heat transfer through a vacuum.

  11. Heat Transfer Coefficient The Measure of the material’s ability to transfer heat. The higher the value, the more heat transfers through the material.

  12. CONDUCTION The transfer of heat from one part of a body to another part or to another body by short range interactions of molecules and/or electrons.

  13. HEAT EXCHANGER FUNCTIONS • Raise system temperature • Lower system temperature • Remove latent heat • Add latent heat

  14. TUBE/SHELL SIDE FLUID SELECTION Based on the following parameters Cleanability Corrosive fluid Pressure Temperature Hazardous or Expensive Fluids Consistency of Flow Characteristics

  15. FIXED TUBE HX

  16. Double Tube Sheet

  17. FIVE FACTORS THAT AFFECT HX OPERATION TEMPERATURE DIFFERENCE FLUID FILM RESISTANCE FILM COEFFICIENT SURFACE AREA FLUID VELOCITY

  18. LESSON 2 TERMINAL OBJECTIVE Given a maintenance activity involving Heat Exchangers the Plant Mechanic will state the steps necessary to clean and inspect heat exchangers as demonstrated by achieving a minimum score of 80% on a written examination.

  19. LESSON 2 ENABLING OBJECTIVES EO01 State the reasons for cleaning and inspecting heat exchangers. EO02 Describe the processes used to mechanically clean heat exchanger tubes. EO03 Describe the basic process used to chemically clean heat exchanger tubes. EO04 Describe the processes used to perform on-line cleaning of heat exchanger tubes. EO05 Describe the processes used to clean heat exchanger shells. EO06 Identify the cleaning methods used on the Main Condensers, MSR's and Feedwater Heaters at PVNGS. EO07 Describe the general inspection procedures for the Moisture Separator/Reheaters. EO08 Describe the general inspection procedures for the Main Condensers. EO09 Describe the general inspection procedures for the Feedwater Heaters.

  20. EO01 State the reasons for cleaning and inspecting heat exchangers.

  21. REASONS FOR CLEANING/INSPECTING EFFICIENCY MINIMIZE CORROSION/TUBING FAILURES IDENTIFY PROBLEMS Damage Leaks Fouling

  22. PRECAUTIONS TAGGING CONFINED SPACE CORRECT SIDE – TUBE/SHELL INTERNAL HAZARDS POTENTIAL TO DAMAGE TUBING [Shell Side]

  23. EO02 Describe the processes used to mechanically clean heat exchanger tubes.

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