Process flow diagram

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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 processflowsheet. It is the key document in process design. [1]

Contents

Typical content of a process flow diagram

Some typical elements from process flow diagrams, as provided by the open source program, Dia. Click for image legend. Pfd-symbols.png
Some typical elements from process flow diagrams, as provided by the open source program, Dia. Click for image legend.

Typically, process flow diagrams of a single unit process include the following:

Process flow diagrams generally do not include:

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.

Process flow diagram examples

The process flow diagram below depicts a single chemical engineering unit process known as an amine treating plant:

Flow diagram of a typical amine treating process used in industrial plants AmineTreating.png
Flow diagram of a typical amine treating process used in industrial plants

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:

A typical oil refinery-SL RefineryFlow.png
A typical oil refinery-SL

Other items of interest

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. Often PFDs are produced on large sheets of paper.

PFDs 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processes can be found in the literature, specifically in encyclopedias of chemical technology, although some might be outdated.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 those available from the United States Patent and Trademark Office can be useful.

Standards

See also

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<span class="mw-page-title-main">Instrumentation in petrochemical industries</span>

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ISO 14617Graphical symbols for diagrams is a library of graphical symbols for diagrams used in technical applications. ISO 14617 consists of the following parts:

References

  1. Sinnott, R. K. (2005). Coulson & Richardson's chemical engineering (4th ed.). Amsterdam Paris: Elsevier Butterworth-Heinemann. p. 133. ISBN   978-0-7506-6538-4.

Further reading