The Process Flow Diagram (PFD) is a schematic illustration of a system.
A Process Flow Diagram - PFD - (or System Flow Diagram - SFD) shows the relations between major components in a system. PFD also tabulate process design values for components in different operating modes, typical minimum, normal and maximum. A PFD does not show minor components, piping systems, piping ratings and designations.
A PFD should include:
Major equipment symbols, names and identification numbers
Control, valves and valves that affect operation of the system
Interconnection with other systems
Major bypass and recirculation lines
System ratings and operational values as minimum, normal and maximum flow, temperature and pressure