User:Milton Beychok/Sandbox: Difference between revisions

From Citizendium
Jump to navigation Jump to search
imported>Milton Beychok
imported>Milton Beychok
No edit summary
Line 1: Line 1:
A '''process flow diagram''' (PFD) is a diagram commonly used by [[Chemical engineering|chemical engineers]] in the [[process engineering]] of [[Petroleum refining processes|petroleum refineries]], [[Natural gas processing|natural gas processing plants]], [[Petrochemical plant|petrochemical]] and [[Chemical plant|chemical plants]] and other industrial facilities to indicate the general flow of plant process streams  and equipment.<ref>{{cite book|author=Martyn S. Ray and Martin G. Sneesby|title=Chemical Engineering Design Project: A Case Study Approach|edition=2nd Edition|publisher=Gordan and Breach Science Publishers|year=1998|id=ISBN 90-5699-136-1}}</ref><ref>{{cite book|author=Richard Turton, Richard C. Bailie, Wallace B. Whiting and Joseph A. Shaeiwitz| title=Analysis, Synthesis, and Design of Chemical Processes|edition=2nd Edition|publisher=Prentice Hall|year=2002|id=ISBN 0-13-064792-6}}</ref><ref>{{cite book|author=James R. Couper, W. Roy Penny, James R. Fair and Stan Walas|title=Chemical Process Equipment: Selection and Design|edition=2nd Edition|publisher=Gulf Professional Publishing|year=2005|id=ISBN 0-7506-7510-1}}</ref>
http://forum.citizendium.org/index.php/topic,2706.0.html


The PFD displays the relationship between ''major'' equipment of a plant facility and does not show details  such as minor equipment items, [[piping]] materials of construction and piping sizes. Another commonly-used term for a PFD is a ''process flowsheet''.
http://forum.citizendium.org/index.php/topic,2706.msg21441.html#msg21441


==Typical content of a process flow diagram==
http://forum.citizendium.org/index.php/topic,2706.msg21453.html#msg21453


{{Image|PFD Symbols.png|right|256px|Examples of typical PFD symbols}}
---------------------


Typically, process flow diagrams of a single [[unit process]] will include the following:
'''Concerned about too much "partial transclusion" of articles'''
* Process piping
* Major bypass and recirculation lines
* Major equipment symbols, names and identification (either by name, number or both)
* Flow directions (indicated by arrows on the process streams)
* [[Pressure]], [[temperature]], flow rate and other [[control valve]]s and systems that monitor and control the operation of the process (shown schematically, rather than in complete detail)
* Interconnecting lines with other systems (if any)
* Pressure, temperature, flow rate and other pertinent operational values for each of the equipment items such as [[pump]]s, [[gas compressor]]s, [[Continuous distillation|distillation columns]] and other vessels
* In some cases, the process flow diagram includes a tabulation that lists the normal temperature, pressure, amount and composition of all the major process streams


Process flow diagrams generally do not include:
Let me try to explain the use of <nowiki><onlyinclude></onlyinclude>, <noinclude></noinclude></nowiki> and <includeonly></includeonly></nowiki> as simply as I can and in the context of what has been discussued in <url=http://forum.citizendium.org/index.php/topic,2706.0.html>here</url>. I shall later herein refer to those terms as "transclusion stuff".
* Pipe classes or piping line numbers
* Pipe sizes
* Process control instrumentation (sensors and final elements) in detail
* Minor bypass lines
* Isolation and shutoff valves
* Maintenance vents and drains
* [[Relief valve|Relief and safety valves]]
* Flanges (if any)


The adjacent image provides some examples of the typical symbols used in PFDs to represent various major equipment items, piping and valves. It is by no means completely inclusive, but it is representative of the great many such symbols commonly used in drawing PFDs.
(1) By placing <nowiki><onlyinclude></onlyinclude></nowiki> around a section of text in the edit page of any article, you are segregating or placing a sort of box around that section of text. That box does not affect the display of the main article page in any way at all. Then you can develop a template that will display the content of that box somewhere else or in multiple somewhere elses.


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''.
(2) By placing <nowiki><noinclude></noinclude></nowiki> around some portion of the segregated text, you are excluding that portion of text from being displayed elsewhere by the template. This also does not affect the display of the main article page in any way at all.


==Process flow diagram examples==
(3) By placing <nowiki><includeonly></includeonly></nowiki> around some new text you introduced into the segregated text, you are entering new text that will be included in the text that is displayed elsewhere by the template but will not be displayed in the main article display. In other words, that also does not affect the display of the main article page in any way at all.
=== Single process unit===


The process flow diagram below depicts a single chemical engineering unit process known as a [[Catalytic reforming|catalytic reforming unit]] which is widely used in most, if not all, petroleum refineries. It does not include all of the above listed process flow diagram components to avoid disclosure of proprietary information and, although not usually done in practice, some color has been added.
The overall net result is that the main article display is not affected in any way at all. However, the article edit page is sprinkled with all that "transclusion stuff" that is strange and weird to the majority of the CZ authors and editors.  


{{Image|CatReformer.png|center|579px|Process flow diagram of a typical semi-regenerative Catalytic Reforming unit in a petroleum refinery }}
So what are Caesar Chinas and I concerned about? Whenever some author or editor unfamiliar with the "transclusion stuff" makes a significant revison to the article, it will mess up the segregated text box and hence mess up the text displayed somewhere else by the template. If, as may easily happen, someone's revision of the article may partially delete or incorrectly re-arrange the "transclusion stuff" and that might then actually mess up the main article page as well. In effect, authors and editors will have to become fairly knowledgeable programmers to avoid messing things up.


=== Multiple process units within an industrial plant===
Caesar and I are also concerened about the proposal at  <url=http://forum.citizendium.org/index.php/topic,2706.msg21441.html#msg21441>here</url> to sprinkle that strange "transclusion stuff" throughout the edit pages of a great many (if not most) of the developed CZ artcles and the fact that it seems to have been unilaterally started to some extent ... without a full and complete discussion here on the forums.
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]]:
 
{{Image|RefineryFlow.png|center|584px|A typical petroleum refinery}}
 
=== Simple block flow diagrams ===
 
Below are two examples of very simple process block flow diagrams. One is a diagram of a [[Refineries|sugar refining process]] and the other is a diagram of a process for producing [[Asphalt (petroleum)|petroleum asphalt]]:
 
{|border="0" align="center"
|-
|valign="center" |{{Image|Sugar Cane Refinery.png|right|308px|Block flow diagram of sugar refining process}}
|&nbsp; &nbsp; &nbsp; &nbsp;
|valign="center" |{{Image|Petroleum Asphalt Flow Diagram.png|right|216px|Block flow diagram of asphalt production in a petroleum refinery}}
|&nbsp; &nbsp;
|}
 
==Other items of interest==
 
A PFD can be computer generated from [[Chemical process simulators|process simulators]]), [[Computer-aided design|CAD packages]], or flow chart software using a library of chemical engineering symbols. Rules and symbols are also available from standardization organizations such as:
 
* ISO 10628: Flow Diagrams For Process Plants - General Rules<ref name=Standards>[http://global.ihs.com/search_res.cfm?currency_code=USD&customer_id=2125482C4F0A&shopping_cart_id=28242827294B20244C5A2D30280A&country_code=US&lang_code=ENGL IHS Standards Store]</ref>
* ANSI Y32.11: Graphical Symbols For Process Flow Diagrams (out of print but in stock as of June 2009)<ref name=Standards/>
 
Many large industrial companies in the process industries, and the engineering companies that serve them, have their own extensive proprietary sets of PFD symbols.
 
PFDs of many commercial processes can be found in the literature, 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.
 
== References ==
{{reflist}}

Revision as of 13:06, 8 June 2009

http://forum.citizendium.org/index.php/topic,2706.0.html

http://forum.citizendium.org/index.php/topic,2706.msg21441.html#msg21441

http://forum.citizendium.org/index.php/topic,2706.msg21453.html#msg21453

Concerned about too much "partial transclusion" of articles

Let me try to explain the use of <onlyinclude></onlyinclude>, <noinclude></noinclude> and </nowiki> as simply as I can and in the context of what has been discussued in <url=http://forum.citizendium.org/index.php/topic,2706.0.html>here</url>. I shall later herein refer to those terms as "transclusion stuff".

(1) By placing <onlyinclude></onlyinclude> around a section of text in the edit page of any article, you are segregating or placing a sort of box around that section of text. That box does not affect the display of the main article page in any way at all. Then you can develop a template that will display the content of that box somewhere else or in multiple somewhere elses.

(2) By placing <noinclude></noinclude> around some portion of the segregated text, you are excluding that portion of text from being displayed elsewhere by the template. This also does not affect the display of the main article page in any way at all.

(3) By placing <includeonly></includeonly> around some new text you introduced into the segregated text, you are entering new text that will be included in the text that is displayed elsewhere by the template but will not be displayed in the main article display. In other words, that also does not affect the display of the main article page in any way at all.

The overall net result is that the main article display is not affected in any way at all. However, the article edit page is sprinkled with all that "transclusion stuff" that is strange and weird to the majority of the CZ authors and editors.

So what are Caesar Chinas and I concerned about? Whenever some author or editor unfamiliar with the "transclusion stuff" makes a significant revison to the article, it will mess up the segregated text box and hence mess up the text displayed somewhere else by the template. If, as may easily happen, someone's revision of the article may partially delete or incorrectly re-arrange the "transclusion stuff" and that might then actually mess up the main article page as well. In effect, authors and editors will have to become fairly knowledgeable programmers to avoid messing things up.

Caesar and I are also concerened about the proposal at <url=http://forum.citizendium.org/index.php/topic,2706.msg21441.html#msg21441>here</url> to sprinkle that strange "transclusion stuff" throughout the edit pages of a great many (if not most) of the developed CZ artcles and the fact that it seems to have been unilaterally started to some extent ... without a full and complete discussion here on the forums.

Retrieved from "https://citizendium.org/wiki/index.php?title=User:Milton_Beychok/Sandbox&oldid=388325"