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  • P&ID – Construction Guide/Manual
  • P&ID is also known as mechanical flow diagram (MFD)
  • Contains: plant construction information (piping, process, instrumentation, and other diagrams)
  • Provides information needed by engineers to begin planning for the construction of the plant
  • Look at V-102 on P&ID
    • V-102 contains an LE (Level Element)
      • LE senses liquid level in separator and adjusts flow rate leaving
      • LE opens and closes a valve depending on liquid level
      • LE and valve represent a feedback control loop

// P&ID Summary

  • The final control element in nearly all chemical process control loops is a valve.
  • Key to understanding the control logic is to identify which flowrate is being manipulated to control which variable.
  • Based on the P&ID diagram:
    • Mech and Civil Engrs will design and install pieces of equipment.
    • Instrument Engrs will specify, install and check control systems.
    • Piping Engrs will develop plant layout and elevation drawings.
    • Project Engrs will develop plant and construction schedules. v
  • Before final acceptance, P&IDs serve as a checklist against which  each item in the plant is checked.
  • Design Case Vs Base Case

// How to Read P&ID

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