Talk:Pyrolysis

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


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)

Contents

[edit] Firefighting

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)

[edit] Term used more loosely?

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)


[edit] Merge?

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)

[edit] Pyrolysis with charcoal production and coke production?

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?

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