Talk:Combustion/Archive 1

Corrosion

I'm removing the sentence that says that corrosion does not produce heat, as I recall my textbook said that it does, it just takes such a long time to produce a single joule it's neglegible.Kr5t 00:41, 2 November 2006 (UTC)

Balancing of combustion equation

I think the generalised alkane combustion equation should read:

CxHy + (x+(y/2))02 --> xC02 + (y/2)H20

--81.136.105.66 15:29, 1 Feb 2005 (UTC)

AND JUST WHEN IT HIT ME< GO TO BED

It should be y/4, because every H reacts with half an O; and one O is half an O2.Kr5t 00:38, 2 November 2006 (UTC)

Complete combustion

For some reason "Complete combustion" page cannot be edited by clicking on "edit" button ... the phrase that says that Iron (III) is an isotope is wrong ... it should refer to an oxidation state of iron.

I changed it.

Factual error

Combustion of a hydrocarbon in oxygen obviously cannot produce any compounds of nitrogen. I think "air" should replace "oxygen".

On an unrelated point, the combustion of CH2S in fluroine is very cute (and should be retained) but probably should not be the first example. Hydrogen burning in oxygen might be more appropriate.

• I agree. It's ridiculous to list Nitrogen as an element in the reaction when it takes no place in it. The reaction doesn't change just because it's taking place in air instead of pure oxygen. (Well, it can, but this equation doesn't reflect that. eg, more byproducts) The combustion reaction takes place between the oxidizer and the fuel, not the oxidizer, the fuel, and some other medium present. If somethign else IS happening with the other, make another equation to reflect it. It's ridiculous to try to balance two different chemical reactions in one equation. --68.68.224.129 17:03, 16 July 2006 (UTC)

First of all, the lead-in paragraph very clearly shows both combustion reaction versions: one version using oxygen and one version using air. It also clearly states "In most cases, combustion uses oxygen obtained from the ambient air" which is an indisputable fact.

It is not ridiculous at all. We should not look upon combustion from the narrow chemistry purist viewpoint. Most cooking ovens, industrial furnaces, incinerators, forest fires, barbecues, vehicle engines and so forth use air for combustion and thus the combustion product gases factually contain more nitrogen than any other component. Designers of combustion equipment need to know how much combustion product gas (i.e., flue gas) is produced so that they can accurately calculate the flame temperature as well as correctly design chimneys and flue gas stacks, and therefore they cannot ignore the nitrogen content of flue gases.

The nitrogen does not take a "free ride" in the combustion process ... some of it is converted to nitrogen oxides. Industrial engineers and environmental protection agencies need to know how much of that nitrogen is converted to nitrogen oxides because there are governmental regulatory limits on nitrogen oxide emissions.

The visitors to Wikipedia constitute a wide range of background ... and we should keep that in mind rather than using labels like "factual error" or "ridiculous" for anything other than the narrow chemistry purist viewpoint. - mbeychok 18:51, 16 July 2006 (UTC)

I just thought it was indeed a chemistry article. Its tone takes that on, and it talks about chemical reactions, and is in two different chemistry lists. It seemed like a reasonable conclusion. However, there is nothing 'narrow' about this viewpoint, it is the proper way to write about chemical reactions in English. When describing the chemical reaction of combustion, shouldn't we make use of the most popular form? If one is running a car engine or a furnace or whatever particular example, one certainly needs to be aware of all reactions present, and the actual volume of air being used. To that end, a proper education in chemistry is required--proper forms of the reactions present.

I never meant to say that the N_2 takes a free ride. An N_2 combustion (or other reactions) present alongside the combustion of the fuel is certainly true. But it is just that, a seperate reaction, that must be considered seperately at the lowest level of the analysis of the entire combustion, alongside, but not combined with the combustion of the main fuel. Therefore, as when the article is discussing the specific chemical process known as 'Combustion', (and not the general 'combustion' in the engine) it is not appropriate to include N_2 in the reaction, because the N_2 combustion is seperate from the combustion of the fuel. If the user is concerned about the N_2 reactions present, as he should be, he must write and balance seperate reactions that take his N_2 into account.

It is foolish to balance multiple independent reactions within the same equation. Furthermore, the equation (Cyanocry)'s edit that was listed in the top of the article did not do anything with the N_2 in its reaction. It simply noted that the N_2 was present, in exactly equal amounts on both sides of the equation, with no actual nitrogen compounds produced. The form removed by Cyanocry would have actually been detrimental to understanding the reality of the entire combustion: that N_2 changes and produces Nitrogen compounds in reactions seperate from the 'main' combustion reaction.--68.68.224.129 03:32, 17 July 2006 (UTC)

68.68.224.129, I give up! You and Cyanocry are intent on writing a theoretical chemistry article rather than an article that would be useful to all Wikipedia readers and I have better things to do with my time than argue with you. You say "I just thought it was indeed a chemistry article." I would like to point that it really is a Wikipedia article ... not a chemistry article to the exclusion of everything else. Who elected the two of you to decide that this article was about "the specific chemical process known as 'Combustion' " to the exclusion of anything else useful and pertinent to the real world use of combustion?

You might as well delete the entire section on "Combustion temperature" because it has numerous references to combustion air, to stoichiometric air to fuel ratios, to excess combustion air, etc. And you should also delete the section on "Incomplete combustion" because it talks about nitrogen oxides being formed when a hydrocarbon burns in air. And don't forget to delete the section on "Combustion instabilities" because it talks about running ground-based gas turbines at lean air to fuel conditions to reduce nitrogen oxides emissions. (May I assume that you know what a gas turbine is?). And, oh yes, a number of deletions should be made in the "See also" section such as the links to Fire, Air-fuel ratio, External combustion engines, Internal combustion engines, Industrial furnaces, Flue gas emissions from fossil fuel combustion, Cooking and Immolation. After all, we can't have any mention of those real-world items in "a chemistry article", can we?

When you have finished gutting the article of all those sections and links, it will have little interest to anyone but chemistry students. Silly me, I thought Wikipedia was about including information rather than excluding it. If I sound angry, it is because I am indeed angry at what you two think should be done to this article. - mbeychok 05:04, 17 July 2006 (UTC)

Improvements needed

• The "Chemical Equation" section should also include the simple equations for combustion using air and should show Nitrogen as a reactant and as a product. Too many people tend to forget that the combustion product gases include all of the nitrogen in the combustion air. And most combustion in open fires, stoves, ovens, hot water boilers, industrial furnaces and industrial steam generators use combustion air ... not oxygen.

• In the "Combustion temperature" section, I don't understand what is meant by "the heat of combustion (calculated from the fuel's heating value) is used entirely for warming up fuel and gas (e.g. oxygen or air)". That simply is not true or else I have completely misunderstood what it meant to say. The heat of combustion in a stove is used heat the combustion air as well as the surrounding air in an enclosed room or home. The heat of combustion in an oven is used to heat the combustion air and to bake or roast something in the oven. The heat of combustion in a hot water boiler is used to heat the combustion air and the hot water for use in a home or other building. Anywhere from 75 to 90 percent of the heat of combustion in a well-designed industrial furnace or steam generator is transferred into the industrial fluid stream or water being heated and/or vaporized. In other words, some of the heat of combustion, in all of the various heating devices that utilize combustion of a fuel, goes into heating the combustion air but most of the heat of combustion goes into providing heat for some useful purpose. The amount of combustion heat that goes into the heating or vaporizing the fuel itself is a very small part of the combustion heat.

I dont quite get your point. Of course in most cases the heat produced is used for a useful purpose in the end , e.g. like the ones you mentioned. But most often, this heat is taken from the flue gases (that have previously been warmed up by combsustion). And even if not, the text explicitly assumes adiabatic conditions. Academic perhaps, but that's what engineers start off with. --Freeatlast 21:39, 15 April 2006 (UTC)

Perhaps,I can make my point clearer. What the article now says is: The formula that yields this temperature is based on the first law of thermodynamics and takes note of the fact that the heat of combustion (calculated from the fuel's heating value) is used entirely for warming up fuel and gas (e.g. oxygen or air).

The heat of combustion is not calculated from the heating value. They are one and the same thing.

The article does not say that the combustion results in hot flue gases which then provide the useful heating. It says that the heat of combustion is used entirely for warming up the fuel and gas (e.g. oxygen or air). That plainly says that all of the heat goes into warming the fuel and the combustion oxygen or air ...which is simply not correct. The flue gas is not oxygen or air. It is mostly nitrogen, carbon dioxide and water vapor when burning fossil fuels with air (which is about 79% nitrogen). Perhaps if it said "entirely for warming up fuel and the combustion flue gases", then it would be acceptable.

As a chemical engineer for over 40 years, I have often calculated adiabatic combustion temperatures so I know full well what adiabatic means. And by the way, adiabatic combustion temperature is much more commonly referred to as adiabatic flame temperature. - mbeychok 01:08, 16 April 2006 (UTC)

• Again in the "Combustion temperature" section, there is no mention of the fact that almost all the various heating devices mentioned above do not operate at stoichiometric conditions. Instead, almost all of them use a certain amount of excess combustion air (i.e., air in excess of the stoichiometric amount) so as to obtain more complete combustion but not so much that the combustion flue gases will fail to comply with governmentally regulated NOx emission limits. There is also no mention that excess combustion air affects the adiabatic combustion temperature. My calculated adiabatic temperatures are:
  • 1800 °C for a typical coal using 20% excess combustion air in a typical power plant
  • 2030 °C for a typical oil using 15% excess combustion air in a typical industrial furnace such as used in oil refineries
  • 1900 °C for a typical natural gas using 12% combustion air in a typical industrial furnace such as used in oil refineries

I don't think we have an oversight here, since the stoichiometric air ratio is mentioned as an influencing factor. But I do agree that you can expound on this issue, especially pointing out the influence of process parameters (such as the air ratio) on certain emissions (I generally think the article could have more to say on emissions). --Freeatlast 21:39, 15 April 2006 (UTC)

In general, writing equations for combustion with oxygen rather than air , neglecting to mention excess combustion air being much more prevalent than stoichiometric combustion, saying that the heat of combustion is calculated from the heating value, and saying that all of the heat of combustion goes into warming the fuel and the combustion air ... all struck me as being as being significant oversights that need revision. I am sure that most experienced engineers would agree with me._ mbeychok 01:08, 16 April 2006 (UTC)

All of the above are significant oversights and should be taken into consideration to improve the science of this article. After all, we should not just define the word "combustion" as if it were an abstraction. We should also focus on the real world uses and applications of combustion. Please excuse me if I sound as if I am preaching. - mbeychok 06:54, 7 April 2006 (UTC)

You seem to be missing the engineering examples in this arcticle (don't mistake that for flaunted science). To explain combustion it makes sense to start abstract as done throughout this article but you may want to add a new engineering section "Practical purposes" (e.g.) and link to other wiki articles. For instance the section "See also" contains a subsection "Machines" which might as well be included directly into such an engineering section --Freeatlast 21:39, 15 April 2006 (UTC)

No, I am not missing having some practical examples included in the article. What I have pointed out are simply incorrect statements as well as oversights. - mbeychok 01:08, 16 April 2006 (UTC)

Re. the whole of the above section.

- Re. technical terms: I'm not entirely confident with the English specialised terms. In particular I wasnt aware that heat of combustion and heating value are the same thing (which explains some previous irritation). Also, if adiabatic flame temperature is the only correct term, we should remove reference to adiabatic combustion temperature. Feel free to correct.

- Re. flue gases: I'm not statisfied with the mention of warming fuel and flue gas in this context. We should either concentrate on heating up the input side of the process (fuel and combustion gas be it air or oxygen) or the output side (combustion products i.e. flue gas plus uncombusted plus ash etc.) but not both. Right now, it's mixed reference (to fuel and flue gas) and just confuses (since flue gas contains combusted fuel). I think it's more straightforward to say "is used entirely for heating the fuel and combustion gases". Of course in this analysis the combustion gas (e.g. air) is only warmed up after combustion has taken place (i.e. when a certain part of it is no longer what it used to be e.g. air). But what is really meant is that the heat capacity equivalent of the input air has been taken out of that released during the combustion process. That's why I think it's fair to say that the combustion heat is used to heat fuel and cobustin gases. Comments?

Freeatlast, I think we are finally both on the same page. If you will read the revisons, most of which I made last night, you will see that I changed that warm up sentence to read "the heat of combustion is used entirely for heating the fuel, the combustion air or oxygen, and the combustion product gases (commonly referred to as the flue gas)". That is exactly what a rigorous calculation of the adiabatic combustion temperature involves.

Please note that "flue gases" and "combustion product gases" have the same meaning in almost all cases. If it is an open fire, of course one would use "combustion gases" rather than "flue gases". For stoves, boilers, ovens, furnaces, fired heaters, etc., either term may be used because the combustion gases usually exit through a flue gas stack or chimney.

As far as terminolgy is concerned, we must all learn to understand each others language. I see no problem with using either or both "adiabatic combustion temperature" or "adiabatic flame temperature", "combustion gases" or "flue gases", "heat of combustion" or "heating value" or "caloric value", "air-fuel ratio" or "Lambda" or "percent excess combustion air", etc. ... as long as the article clearly spells out the alternative terminologies, which is part of what I also included last night. In other words, I don't think we should indicate in any way that there is only one prescribed terminology to be used. I think it is part of our duty towards readers of the article to educate them on that point. Another way of putting it is that chemists, engineers, physicists, etc. all have their own commonly used terminology and all are equally valid. Cheers, - mbeychok 21:59, 16 April 2006 (UTC)

Agreed. --Freeatlast 20:11, 28 April 2006 (UTC)

Removing edit by 24.109.226.234

I am removing the edit made by 24.109.226.234 on this date wherein the balanced equation for methane combustion was added to the section on Turbulent Combustion because it was out-of-context with that section and there was no explanation as to why it was added there. Besides, that equation appears in the lead-in section of the article anyway. - mbeychok 21:12, 11 May 2006 (UTC)

Repeat of my above response to comments and deletions of 68.68.224.129 and Cyanocry

I am repeating my final response made above in the section entitled "Factual Error" because I want to make sure that all future readers of this Discussion page read what I said:

68.68.224.129, I give up! You and Cyanocry are intent on writing a theoretical chemistry article rather than an article that would be useful to all Wikipedia readers and I have better things to do with my time than argue with you. You say "I just thought it was indeed a chemistry article." I would like to point that it really is a Wikipedia article ... not a chemistry article to the exclusion of everything else. Who elected the two of you to decide that this article was about "the specific chemical process known as 'Combustion' " to the exclusion of anything else useful and pertinent to the real world use of combustion?

You might as well delete the entire section on "Combustion temperature" because it has numerous references to combustion air, to stoichiometric air to fuel ratios, to excess combustion air, etc. And you should also delete the two sections on "Complete combustion" and "Incomplete combustion" because they talk about nitrogen oxides being formed when a fuel burns in air. And don't forget to delete the section on "Combustion instabilities" because it talks about running ground-based gas turbines at lean air to fuel conditions to reduce nitrogen oxides emissions. (May I assume that you know what a gas turbine is?). And, oh yes, a number of deletions should be made in the "See also" section such as the links to Fire, Air-fuel ratio, External combustion engines, Internal combustion engines, Industrial furnaces, Flue gas emissions from fossil fuel combustion, Cooking and Immolation. After all, we can't have any mention of those real-world items in "a chemistry article", can we?

When you have finished gutting the article of all those sections and links, it will have little interest to anyone but chemistry students. Silly me, I thought Wikipedia was about including information rather than excluding it. If I sound angry, it is because I am indeed angry at what you two think should be done to this article. - mbeychok 05:04, 17 July 2006 (UTC)

Reverting changes made by User:Cyanocry

Neither User:Cyanocry or User:68.68.224.129 have responded to my above comments on the deletions and changes made by User:Cyanocry. Nor has either of them responded to a copy of my above comments posted to their Talk pages two days ago. I am therefore deleting the changes made by Cyanocry and reverting back to the last version by User:AntiVandalBot. - mbeychok 19:31, 19 July 2006 (UTC)

Remove tag to "See also combustion (software)

Someone added a tag at the top of this Combustion article that says "See also: Combustion (software)". When I went there, I found an article that seemed to me to be purely an advertisement for some software that creates pictures of fires for use in composing video graphics.

Do any of you agree with me that such software has nothing of value relative to the Combustion article? Please let me know so that I don't act too hastily in removing the tag. - mbeychok 01:29, 15 August 2006 (UTC)

Since nobody seems to have an opinion one way or the other, I am taking the bold step of removing the tag. - mbeychok 23:40, 19 August 2006 (UTC)

The recently added "Analysis section"

Hello all:

I feel that the entire new "Analyis section" is just a jumble of data graphs with no explanations and no references. I think it should be deleted until the editor-author:

• Reduces all the white space in each of the images and frames them so that at least some of them could be placed two abreast.
• Uses a more easily legible text in the images.. Some of the text is so small, that it is difficult to read.
• Converts the images from .gif format to .png format.
• Adds some discussion of and explanation of the various images, as well as references to the source of the data.

Much of that data (for example, the enthalpy versus temperature graph and the two heating value plots) is readily available it the NIST online website as well as in many textbooks and handbooks.

What do all of you think? Please comment. - mbeychok 05:51, 2 December 2006 (UTC)

Agree with all of the above. I've moved the section to a user work page User:Engware/work to be refined and cleaned up. As is there is too much image and too little analysis. Please view and comment on the user's work page. Vsmith 13:39, 2 December 2006 (UTC)

Engware has reworked his "Analysis" section completely and it now reads quite well and is well organized. I no longer have any objection to his contibuting it for everyone's review here, which he has now done. - mbeychok 01:00, 5 December 2006 (UTC)

Reasons for removing photos added by User:Donarreiskoffer

I deleted the images for these reasons:

• They were very poor choices. The first one (ethanol combustion) was almost completely black with just a smear of blue. Without a title, you wouldn't know it was a flame. I don't believe that an technical article on combustion needs photos at all, and especially photos that depict alcoholic cocktails and cigarette smoking.
• There is a Wikipedia article called Fire and the three photos would added by User:Donarreiskoffer would be more appropriuate there. In fact, one of them is already in that article.
• If photos are used (and I repeat that I don't believe they are needed) then Wikimedia Commons has a good many better choices. Just search Commons with the keyword "fire" and you will find them.

Please don't revert those photos back in again without first having some thorough discussion here on this Talk page. - mbeychok 18:47, 5 January 2007 (UTC)

is the www.survivaltopics.com/fire/fire-tetrahedron/ The Fire Tetrahedron external link appropriate here?

The www.survivaltopics.com/fire/fire-tetrahedron/ The Fire Tetrahedron external link recently added by User:69.205.8.94 is about building a fire for survival when lost in a wilderness. I don't think it is appropriately relevant to this article. There is a Wikipedia article named Fire and it would probably be more approprate there. What do others think? Let's here from some of you! - mbeychok 00:06, 28 March 2007 (UTC)

Wouldent think this would be appropriate. Seems to be adsense spammed site by 69.205.8.94, I'm sure there are better reliable sites that the content origionated from--Hu12 00:22, 30 March 2007 (UTC).

Discussion Cleanup

I think this discussion page is getting a bit too bloated for its own good to have a meaningful discussion about the future of the Combustion article. I would like to purge this page of resolved disputes and old arguments if there are no objections. BlatantHeroics 18:33, 11 May 2007 (UTC)

Purging or deleting of Discussion pages is seriously frowned upon. What you can do is to simply create a Discussion Archive page and provide a Wiki link to that page at the top of this page. Then you could cut and paste old discussion items into that archive page. Please try not to archive resolved disputes which might arise again because people don't bother to read the archived pages. - mbeychok 18:46, 11 May 2007 (UTC)

I understand the point about the archives, however the majority of the clutter is from the resolved disputes since they span 5-8 paragraphs and some of it is just bickering. I suggest the following compromise, these long discussion are moved to the archives and replaced with a short summary on the discussion page concerning what the dispute was about, its resolution, and where to find the details. BlatantHeroics 23:56, 11 May 2007 (UTC)

That would be fine with me. Regards, - mbeychok 01:44, 12 May 2007 (UTC)