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 a plant facility and does not show minor details such as piping details and designations. Another commonly-used term for a PFD is a flowsheet.
Contents |
[edit] Typical content of a process flow diagram
Typically, process flow diagrams of a single unit process will include the following:
- Process piping
- Major equipment items
- Control valves and other major valves
- Connections with other systems
- Major bypass and recirculation streams
- Operational data (temperature, pressure, flow, density, etc.), often by stream references to a mass balance.
- Process stream names
PFD's should not include:
- Pipe classes
- Piping line numbers (line identifiers)
- Minor bypass lines
- Isolation and shutoff valves
- Maintence vents and drains
- Relief and safety valves
- Specific class information
Process flow diagrams of multiple process units within a large industrial plant will usually contain less detail and may be called block flow diagrams or schematic flow diagrams.
[edit] Examples
[edit] Process flow diagram of a single process unit
The process flow diagram below depicts a single chemical engineering unit process known as an amine treating plant:
[edit] Process flow diagram of multiple process units within an industrial plant
The process flow diagram below is an example of a schematic or block flow diagram and depicts the various unit processes within a typical oil refinery:
[edit] Other items of of interest
Often PFD's are drawn in large sheets of paper. A PFD can be computer generated from process simulators (see List of Chemical 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processes can be found in the literature, specifically in encyclopedias of chemical technology, although some might be outdated.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 available from the United States Patent and Trademark Office can be useful.
[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
- DIN 28004 P10: Flow Sheets And Diagrams Of Process Plants; Terms And Definitions
- ANSI Y32.11: Graphical Symbols For Process Flow Diagrams
- SAA AS 1109: Graphical Symbols For Process Flow Diagrams For The Food Industry
[edit] External Links
[edit] Recommended reading
- 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.
