Talk:Combustion

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Archives

1. Inception - May 2007

1 Respiration
2 Spontaneous Combustion
3 Factual error
4 Example
5 Improvements needed
6 Formation of formaldehyde
7 Combustion Analysis ?
8 Reverting of Pvsheridan's comment about fossil fuels
9 No mention of radicals?
10 Hydrocarbons
11 addition
12 Away from the basics
13 double replacement vs. single replacement.... and plasma
14 Heat of Combustion of Sulfur
15 Combustion
16 What Chemicals was released?

[edit] Respiration

I don't think respiration should be included in this page. I thought the definition of "combustion" was rapid oxidation, so by definition there can't be "slow combustion". --Keenanpepper 01:28, 14 Oct 2004 (UTC)

Speed has nothing to do with whether combustion occurs or not, it has to do with what the reactants are. As long as you have a hydrocarbon reacting with oxygen which is creating carbon dioxide, and sometimes carbon monoxide and/or water as well, you have combustion. Respiration is O₂ reacting with the various forms of carbon in an organism, and it creates CO₂ as a result. Therefore, by definition, it is combustion. --BMS 03:47, 16 Dec 2004 (UTC)

But the definition states combustion is accompanied by the production of heat or both heat and light in the form of either a glow or flames.I do not believe this happens in respiration (except fot the inevitable increase in entropy). Is the definition not accurate then? Manuel N —Preceding unsigned comment added by 84.120.147.37 (talk • contribs) 7 December 2006 (UTC)

[edit] Spontaneous Combustion

The spontaneous combustion page disambiguates to this page and this page has a link to spontaneous combustion but neither actually describes what it is or how it works. Which should contain information or should a third page be created?

I think that someone should add to this page, under "types" of combustion. Bernard S. Jansen 04:14, 15 January 2007 (UTC)

[edit] Factual error

This was a dispute over the inclusion of N2 in the equation of complete combustion since it doesn't react. It was decided it should be kept since it affects the temperature and does react to make minor species. Full details are in the Combustion Archive.

[edit] Example

in the example in the intro carbon is made a link in the reaction. Why? It is no more relevant than the other elements. Ozone 00:34, 1 January 2006 (UTC)

[edit] Improvements needed

This was a dispute that spawned from confusion over different terminology meaning the same thing, particular adiabatic combustion temperature with adiabatic flame temperature and heat of combustion with heating value. It was decided that a more conscious effort should be made to include multiple terminology but to also to point the terms are equivalent. Full details are in the Combustion Archive.

[edit] Formation of formaldehyde

Formaldehyde says that it can be formed by incomplete combustion. What kind of reaction would result in formaldehyde? Just taking a wild stab in the dark with methane:

$C H_4 + O_2 \to H_2 C O + H_2 O + heat$

I have no idea if that's a valid reaction but the elements at least are equal on both sides... Cburnett 05:02, 11 April 2006 (UTC)

The primary source of Formaldehyde in a steady flame is the reaction between the methyl and oxygen radical shown below.

$CH_3 + O \to CH_2O + H$

There are other reactions that'll make Formaldehyde but their rate of reaction are orders of magnitude lower. The most important of these are two reactions that are dominant during the ignition process because the concentration of the oxygen radical hasn't built up yet.

$CH_3O + M \to CH_2O + H + M$

$CH_3O + O_2 \to CH_2O + HO_2$

boy that is complicated--Kkidd (talk) 14:55, 18 May 2008 (UTC)

For the sake of completeness there is one more worth mentioning but it is the slowest of the four.

$CH + H_2O \to CH_2O + H$

BlatantHeroics 00:05, 24 June 2007 (UTC)

[edit] Combustion Analysis ?

In the short section called "Combustion Analysis", it is defined as the determination of the compounds created by combustion. Though, I added a link to a page called "Combustion Analysis" regarding -mainly- the application of exhaust fume analysis to the determination of combustion efficiency. We have here two different fields related to the same term: theory of chemistry and empirical thermal engineering. Does anyone can help to get an agreement on the definitions ? Kekel 20:04, 20 April 2006 (UTC)

Kekel, I really don't see any major difference. Combustion analysis (what you call "theory of chemistry") involves combusting an organic compound, analyzing the products of combustion and then using that information to determine the formula of the organic compond. The combustion link you added also analyzes the products of combustion and then uses that information to determine the quality of the combustion.

Both procedures involve combustion and analyzing the products of combustion. Both use that information to find additional useful information. I really don't see that as a conflict between "theory of chemistry" and "empirical thermal engineering". Nor do I understand why you labeled the boiler usage as "empirical". It is no more or no less empirical than the other usage. -mbeychok 18:23, 21 April 2006 (UTC)

Still, one approach is qualitative (the "chemistry" one) and the other is more quantitative (the "engineering one"). It makes a difference in my mind. But no big deal probably. The real thing is it would be nice if this section, "combustion analysis", could be developed in one way or another. Actually, I don't have the basics for this. I only entered the field cause I was looking for some info for my work that I finally found through this link.

Kekel 21:46, 23 April 2006 (UTC)

not really interested in the debate between chemistry related analysis vs. engineering related analysis- but I included a small section about combustion analysis at the end of the incomplete combustion section- where it applies practically?johntindale (talk) 15:55, 14 May 2008 (UTC)

[edit] Reverting of Pvsheridan's comment about fossil fuels

Pvsheridan had entered a paragraph in the Combustion Analysis stating that the term "fossil fuel" was a misnomer and that Wikipedia should completely remove that misnomer from all its articles. His reasoning was that "recent finds" made it obvious that the more correct term was "hydrocarbon fuels" ... presumably because hydrocarbon fuels did not originate from fossilized animals. He failed to furnish any source references or proof of his contention.

Since the term "fossil fuel" exists in a very great many Wikipedia articles and probably hundreds of thousands of books, magazines, journals, encyclopedias and web sites, that is a pretty drastic step that Pvsheridan is asking for. It really doesn't belong in any section of this article. I suggest that he/she make his proposal at the Wikipedia Village Pump. For that reason, I removed his paragraph from this article by reverting to the previous version. - mbeychok 22:16, 23 April 2006 (UTC)

[edit] No mention of radicals?

Why are free radicals not mentioned anywhere in this article? Aren't they necessary for the survival of a flame?--Joel 19:46, 6 June 2006 (UTC)

Yes, it should definitely be mentioned that the mechanism of a combustion reaction (at least when oxygen is a reactant) is via radicals. There is an good section on combustion in the radical article that should be integrated into this page. --Tospik 23:37, 24 July 2007 (UTC)

[edit] Hydrocarbons

Should this be expanded to cover combustion of eg alcohols, alkenes, etc. Joseph Sanderson 17:16, 8 October 2006 (UTC)

[edit] addition

would it be possible for somebody to add information about elemental impurities during combustion affecting what the products are? Although a few elements, such as sulfur and iron, were mentioned, I think that should be expanded to include a more general discussion of the combustion of other elements, like maybe silicon, or phosphorus, or boron. 65.78.17.194 20:22, 13 October 2006 (UTC)

[edit] Away from the basics

Does anyone understand what characteristic of oxygen makes combustion happen? What is it about reactions with that specific element that makes fire? How does that attribute work which makes it different from any other reaction that is not combustion? I'd appreciate any input. Thank you.

[edit] double replacement vs. single replacement.... and plasma

Could someone please explain the difference between 'double replacement' and 'single replacement' in the following sentence? They aren't linked to another document to explain them: Combustion is double replacement, on the other hand a chemical reaction is single replacement.

Also, it would be great if someone would go into more detail about how and when fire/combustion is like a plasma (either on the combustion page, or the fire page).

Thanks!

Isabelle Hakala 04:11, 19 April 2007 (UTC)

[edit] Heat of Combustion of Sulfur

What is the heat of combustion of sulfur? Here it is listed at 9261 kJ/kg which is equal to 3982btu/#, but on the "Heat of Combustion" entry it is listed at 4.639MJ/kg, which is 1995 btu/#.... —Preceding unsigned comment added by 74.0.223.151 (talk) 13:33, 11 September 2007 (UTC)

The value given in this article is for solid sulfur and is correct. The value in the Heat of combustion article is incorrect and I have corrected it. - mbeychok 20:17, 11 September 2007 (UTC)

[edit] Combustion

Combustion is made when a complex sequence of axothermic chemical reactions betwwen a fuel and an oxidant ccompanied by the production of heat or both heat and ligh in the form of either a glow or flame. In other words its a specific reaction that happends wen there a chemical bond. When these 2 chimicals bond and form a combustion it usually oxidises. —Preceding unsigned comment added by 72.187.134.27 (talk) 03:28, 31 October 2007 (UTC)

Not all exothermic reactions should be considered combustion. For example, when carbon and hydrogen react to form methane, heat is evolved, but I don't think anybody regards this as "combustion". And when oxygen is added to methane to form methanol, calling this combustion pushes the term to a point where it's meaning becomes too diffuse to be useful.Thermbal 05:34, 9 November 2007 (UTC)

[edit] What Chemicals was released?

During the burning of slate dumps there where chemicals relased from these burning slate dumps, Does anyone know what the chemicals was in English terms and was it toxic? —Preceding unsigned comment added by 75.108.161.89 (talk) 15:13, 15 February 2008 (UTC)