Talk:Pyrolysis

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Uncategorized[edit]

(added in retrospect)--Tunheim 19:10, 3 February 2007 (UTC)

--Alex 08:31, 17 July 2006 (UTC)

I still think that there should be a section on bio-oil: 1) There are 4 sections on solid products of pyrolysis: charcoal, biochar, coke and carbon fiber. There is only 1 section on biofule that looks at liquid products. This is unbalanced. 2) The current section on biofuel ignores the real difficulties encountered when using bio-oil as a fuel. 3) Although some companies, recently, have used bio-oil as a biofuel, the companies that have been in business for more than 10 years produce bio-oil for non-fuel applications (Ensyn and RTI, for example). It would better to replace the "bio-fuel" title by "bio-oil" and, then, talk about fuel and other applications. Cbriens (talk) 05:55, 12 January 2009 (UTC)

I slightly modified the first sentence of the Anhydrous Pyrolysis section to make it compatible with the rest of the article, i.e. the presence of a section on Hydrous Pyrolysis.--Cbriens 17:06, 27 October 2007 (UTC)

This page needs a subsection on Waste pyrolysis plants which are being globally proposed as alternative waste treatment solutions.--Alex 11:48, 25 July 2006 (UTC)

  • i've shifted things around a bit, there is a new section which includes waste as an industrial source David Woodward 08:01, 28 October 2007 (UTC)


It says: "Pyrolysis typically occurs under pressure and at operating temperatures above 430°C (800°F)." This phrase applies only to *some* process of *industrial* pyrolysis, which should be specified (perhaps pyrolysis of wood scraps and sawdust to generate charcoal+?). Pyrolysis is a general term and it can occur anywhere (nature, kitchen, lab, etc.), to any (organic?) substance, at temperatures as low as 100°C. Jorge Stolfi 01:43, 11 Mar 2004 (UTC)

Firefighting[edit]

Why is this article in the firefighting category? --Andrew 20:04, Feb 7, 2005 (UTC)

You’re absolutely right 212.102.225.147 11:06, 23 Jun 2005 (UTC)
I believe you mean "Yes, that was an error". Thanks for fixing the categories. (SEWilco 14:36, 23 Jun 2005 (UTC))
Yep... you’re also right. Weird, two agreeings on such a little talk page. 212.102.225.147 29 June 2005 06:51 (UTC)
I can see how it makes sense. A lot of the knowledge on how to best pyrolyse materials has actually been invented by the people that work with preventing it. In firefighting, or more specifically when making fire-dampening (what is the right term here) materials, you wanna avoid too much pyrolysis. So pyrolysis is a very important reaction to long-term firefighting, just like uv-induced high-altitude detoriation might be an issue for the flight industry. Even though the day to day people might not be thinking to much about it (firefighters / pilots, depending on the example). --Alf 17:05, 27 July 2006 (UTC)
Added Pyrolysis#Fire protection. Makes sense now? --Tunheim 11:48, 21 March 2007 (UTC)

some discussion recently in New Scientist about unburnt pyrolysis products: http://environment.newscientist.com/channel/earth/mg19526151.900-ignition-impossible-when-wildfires-set-the-air-alight.html http://www.newscientist.com/article/mg19526200.600-burning-bush.html David Woodward 08:08, 28 October 2007 (UTC)

Term used more loosely?[edit]

I believe this term is sometimes used more loosely to mean "heating to decompose organic materials" (absense of O2 not specified). I know that this is not really correct, but I have see this in, for example, analytic glassware cleaning protocols. Can anyone confirm this looser definition? ike9898 22:27, 6 December 2005 (UTC)

The strictest definition is that contained in the very term pyrolysis: decomposition or dissolution (lysis) by intense heat or by fire (pyros, both from Greek). When it comes to organics, of course, the absence of O2 is in most cases a must so that oxidation or combustion are not the main reactions. So you are partially right.--Unconcerned 08:05, 7 December 2005 (UTC)
Hmm. I don't understand your meaning. If you are trying to eliminate surface contaminants, do you really care if those contaminants are oxidized or combusted? ike9898 14:43, 7 December 2005 (UTC)
Well, the term might be used in some cases as a fancy substitute for burning, but the chemical reaction/process of pyrolysis is fundamentally different from a combustion process in that the reactant molecules are fragmented without any incorporation of new atoms. It'd be nice though if you could include in the article the specific usage you say you're aware of.--Unconcerned 05:23, 8 December 2005 (UTC)
I'd say this is an example of mis-use of the word. Simple and easy :P --Tunheim 19:13, 3 February 2007 (UTC)

Merge?[edit]

There's three closely related articles on this general topic: This one, Destructive distillation and Cracking (chemistry). The cracking article is mostly concerned with petroleum, but the Pyrolysis and Destructive distillation have large overlaps. I think at least those two should be merged. Toiyabe 22:30, 22 February 2006 (UTC)

  • all the keywords are all used in a different context, different application, you can see for yourself when you look at the what links here. These articles should not merge. V8rik 00:03, 23 February 2006 (UTC)
The "what links here" for Pyrolysis and Destructive Distillation look pretty similar in application and context to me. Can you explain what the difference between Pyrolysis and Destructive Distillation is? Toiyabe 01:22, 23 February 2006 (UTC)
pyrolysis in the laboratory is actually used in organic synthesis particularly radical chemistry and rearrangements. Destructive Distillation is an industrial process. V8rik 17:56, 23 February 2006 (UTC)
I am no chemist, but I would guess that "Destructive distillation" (DD) is generally used for industrial processes, and implies that the distilled phases are condensed and used; whereas pyrolysis is a geeneral chemical process, that may happen in any settings (including by accident) and does not imply recovery or use of the byproducts. So DD uses pyrolysis, but there is much pyrolysis that is not DD. Makes sense? Jorge Stolfi 12:51, 23 February 2006 (UTC)
OK, I can live with that. To be consistent, a lot of the links to pyrolysis should be moved to DD. DD and pyrolysis should include text that explains the distinction. Toiyabe 16:50, 23 February 2006 (UTC)

I have suggested that the stub "Dry distillation" be merged into this article because:

  • Dry distillation is essentially the same as pyrolysis.
  • This is much more of a complete article than is the stub suggested to be merged into this article.

I have tagged both this article and the stub with merge tags. - mbeychok 21:34, 7 May 2006 (UTC)

    • Dry distillation is not the same as pyrolysis. Dry distillation does not necessarily involve chemical decomposition. Destructive distillation is pyrolysis with collection of produced gases.

These should not be merged. According to the "dry distillation" entry, there is an intent to collect the byproducts from a reaction, so it is a process. Pyrolysis refers to general chemical thermal decomposition, with or without oxygen present, and the compound doesn't even have to be organic. Sometimes industrial or lab terminology hijacks a strict definition to make it into more of a process definition. If this is the case for a specific use of the term "pyrolysis", a link should be added to point to "dry distillation". 208.223.129.170 14:38, 1 June 2006 (UTC)


  • Non-mergers win by a small but perceptible margin, merge notice removed..... V8rik 22:24, 12 August 2006 (UTC)
To me dry distillation and destructive distillation seems to be the same thing. It has been previously stated in the discussion thread of both articles that they are not the same thing (A B). However no explanation or references has been given to back up the statement. Would someone care to explain the difference? Please reply at destructive distillation talk page. --Alf 09:33, 22 December 2006 (UTC)

Pyrolysis with charcoal production and coke production?[edit]

I am not especially happy that the two industrial examples above are listed as examples of pyrolysis. Strictly speaking, they are not. Both involve partial combustion using air in order to generate the heat required for the pyrolysis. In both examples about 10% of the material is combusted, to pyrolyse the other 90%. I am not arguing that these processes don't contain pyrolysis, they do. But they are not examples of pyrolysis in its true sense, which must, by necessity involve indirect heating (to avoid contact with oxygen or toher reagents). What do you think?

I think they are important examples of pyrolysis being part of an industrial/chemical process. Just like an ion transfer or a reduction might be part of a more complex chemical process. As long as we make it clear that the pyrolysis is fueled by the heat from the combustion. So in my opinion it's a good example, but it might be possible to write it better. --Alf 09:42, 22 December 2006 (UTC)

I added other processes that do not use partial combustion--Cbriens 18:37, 2 January 2007 (UTC)

Link spam[edit]

Presently (http://en.wikipedia.org/w/index.php?title=Pyrolysis&oldid=105365069) there are multiple links in the article to companies working with pyrolysis technology. They are incorporated into the text. However, to me, it makes the article seem a little more like a buyers guide than an encyclopædic article. Any thoughts? Are there any Wikipedia policies, discussions or guidelines on this? Also, unless I receive any good reasons to keep these links, I'll probably remove them. --Tunheim 09:59, 6 February 2007 (UTC)

I agree. Remove them. No disrespect to the companies concerned, but they do not deserve special status amongst hundreds of others. The examples of particular company processes give detail but not depth or understanding to the article. Indeed, they tend to give a bias and a suggestion that this is something new.Chemical Engineer 21:49, 1 September 2007 (UTC)

  • totally agree, i've just had a big session on this page and done some work on cleanup from this point of view. Relevant policy is WP:SOAP, specifically in these cases WP:NOT#ADVERTISING. I've changed some comm. links to alternative refs, burrowed down in comm. sites to link to more useful page rather than comm. front page, removed some paras all together (e.g. mobile fluidized bed). I have left some comm links in an external links section, since there is some relevance. Hopefully this has lifted the article standard. I think this is a particularly important article because of the potential for carbon seq. David Woodward 08:17, 28 October 2007 (UTC)

more to do[edit]

i'm wikied out at the moment, having left some jobs undone, i will probably be back, but here are some to-do's for anybody

  • probably remove some detail about biochar, i don't want to lose material thought, so this might be transferred to biochar if it is not already duplicated there
  • maybe too much info still in "4. Processes for biomass pyrolysis"? David Woodward 08:22, 28 October 2007 (UTC)
  • Reference 14 doesn't exist anymore. Link does not work anymore. — Preceding unsigned comment added by Thvranken (talkcontribs) 15:48, 22 November 2012 (UTC)

Comment[edit]

This page should include a link to "Wood Gas" and to "Charcoal". The pyrolysis of wood produces a solid; the charcoal, and also gasses; the "wood gasses". These are all related concepts. I haven't figured out how to add links or I would do it myself. Alexander Selkirk Alexselkirk1704 (talk) 17:37, 12 April 2008 (UTC)

Microwaves should be mentioned as they are used for this. 80.186.110.204 (talk) 08:44, 3 July 2009 (UTC)

"bio-oil" redirect[edit]

I think this should be changed because of the product called Bio-Oil (TM) http://www.bio-oil-direct.co.uk/ Eugene-elgato (talk) 18:35, 8 February 2009 (UTC)

Agreed, I didn't expect to come here either 87.194.30.190 (talk) 21:47, 8 May 2009 (UTC)
In the research field, we call it either bio-oil of pyrolysis oil. Kind of like "Kleenex" has come to be the name of nose-tissues. If it really bothers you, go ahead and change all references to "bio-oil" to "pyrolysis-oil" (or "py-oil"). PyrolysisGenius (talk) 23:19, 25 June 2012 (UTC)

Carcinogens[edit]

Some mention of the carcinogens produced by the pyrolysis of food would be appropriate. 78.144.248.102 (talk) 10:42, 30 October 2009 (UTC)

This site mentions that heterocyclic amines and polycyclic aromatic hydrocarbons are known carcinogens produced when muscle meat is cooked at high temperatures. The site does not specify whether this is due to pyrolysis or some other process. http://www.cancer.gov/cancertopics/factsheet/Risk/cooked-meats The12thMan (talk) 21:41, 8 July 2011 (UTC)

Pyrolysis or non-organic materials[edit]

The article has been modified so as to imply that pyrolysis applies only to organic substances. However the term seems to be used also for inorganic substances, e.g. "Yakubovich and coworkers obtained insoluble polymers [...] by the pyrolysis of phosphazene phosphoxides at 220°C." [1]. So I will restore the original wording "mainly used for organics" (but not exclusively). All the best, --Jorge Stolfi (talk) 22:55, 4 January 2010 (UTC)

Same as Thermolysis?[edit]

The article states that pyrolysis is a special case of thermolysis. However, reading both articles, I could not find or imagine an example of thermolysis that is not a pyrolyis. In fact, the IUPAC Gold Book defines them as synonyms. http://goldbook.iupac.org/P04961.html and http://goldbook.iupac.org/T06326.html. Do you agree with that? 200.164.157.164 (talk) 19:21, 14 April 2010 (UTC)

Yes! The pages ought to be the same. However, thermolysis has colloquially come to be more broad (temperature-wise), including gasification and torrefaction as well. I don't know why, though. PyrolysisGenius (talk) 23:21, 25 June 2012 (UTC)


Pyrolysis is usually reported as a special case of thermolysis in review papers examining biomass as pyrolysis feedstock. I agree that coal for instance can be described as operated on by pyrolysis and thermolysis (with no difference at all?). If it is just a semantics issue, it'd be worth a note in the article about which scientific "cliques" use what term. I know torrefaction is usually considered a low temperature (200 celsius or less?) form of pyrolysis. Hero of Ludi (talk) 03:36, 17 August 2012 (UTC)


Chemistry and Biofuel sections edit[edit]

I expanded (actually rewrote) the Chemistry section to add more detail and improve the sense. I agreed with the original author, but just tried to add a little more detail from a personal survey of recent research. I neglected to add additional citations (I just left the original citation in place). I will add citations.

I also added a little more detail to the Biofuel section and linked out to biomass sources by name. I didn't add citations, but they could be added. Hero of Ludi (talk) 03:40, 17 August 2012 (UTC)

Laser cutting.[edit]

I believe (but don't have refs) that laser-cutting of wood produces it's effect by pyrolysis. If that's correct, it would be a useful addition to the Examples section. SteveBaker (talk) 20:10, 16 April 2013 (UTC)