Process Flow diagram
From Wikipedia, the free encyclopedia
A Process Flow Diagram (PFD) is a diagram commonly used in chemical and process engineering to indicate the general flow of plant processes and equipment. The PFD displays the relationship between major equipment of the plant facility and does not show minor details such as piping details and designations.
Typically, a PFD will include the following
- Process Piping
- Major equipment and their tag numbers/ID
- Control valves and other major valves
- Connections with other systems
- Bypasses and circulations
- Operational data (temperature, pressure, flow, density, etc...), usually by stream references to a mass balance.
- Composition of Fluids
PFD's should not include
- Pipe classes
- Line numbers
- Minor bypass lines
- Isolation and shutoff valves
- Maintence vents and drains
- Relief and safety valves
- Specific class information
Instrumentation, pumps and valves are omitted at this level of analysis. A more detailed description which does include this items is the Piping and Instrumentation Diagram (P&ID). A less detailed description of the process is the block flow diagram (BFD), which comprises a series of connected blocks (rectangles) including only the main flows and processes (A block might contain several pieces of equipment).
Often PFD's are drawn in large sheets of paper. A PFD can be computer generated from process simulators, CAD packages, or flow chart software using a library of chemical engineering symbols. Rules and symbols are available from standardization organizations such as DIN, ISO or ANSI
PFD's of many commercial processes can be found in the literature, specifically in encyclopedias of chemical technology, although some might be outdated. To find recent ones patent databases such as the by the U.S. patent and trademark office can be useful.
[edit] References:
M. S. Ray M.G. Sneesby, Chemical Enginering Design Project, A case Study Approach, Gordon and Breach Science Publishers. 1998.
R. Turton R.C. Bailie, W.B. Whiting, J. A. Shaeiwitz, Analysis, Synthesis and Design of Chemical Processes, Prentice Hall, 2003.
Ullman’s Encyclopaedia of Chemical Technology, 6th Edition, Wiley-VCH, 2002.
Kirk-Othmer Encyclopaedia of Chemical Technology, 4th Edition, Wiley, 2001.
[edit] Standards
BS EN ISO 10628: FLOW DIAGRAMS FOR PROCESS PLANTS - GENERAL RULES
DIN 28004 P1: FLOW SHEETS AND DIAGRAMS OF PROCESS PLANTS; CONCEPTS, TYPES OF DIAGRAM, INFORMATION CONTENT
DIN 28004 P2: FLOW SHEETS AND DIAGRAMS OF PROCESS PLANTS DRAWING INSTRUCTIONS
DIN 28004 P3: FLOW SHEETS AND DIAGRAMS OF PROCESS PLANTS
DIN 28004 P4: FLOW SHEETS AND DIAGRAMS OF PROCESS PLANTS; SYMBOLS
ISO 10628: FLOW DIAGRAMS FOR PROCESS PLANTS - GENERAL RULES
ANSI Y32.11: GRAPHICAL SYMBOLS FOR PROCESS FLOW DIAGRAMS
DIN 28004 P10: FLOW SHEETS AND DIAGRAMS OF PROCESS PLANTS; TERMS AND DEFINITIONS
SAA AS 1109: GRAPHICAL SYMBOLS FOR PROCESS FLOW DIAGRAMS FOR THE FOOD INDUSTRY
