Editing Combustion (section)

==Temperature==
[[File:Zoom lunette ardente.jpg|thumb|[[Antoine Lavoisier]] conducting an experiment related to combustion generated by amplified sunlight]]
Assuming perfect combustion conditions, such as complete combustion under [[adiabatic]] conditions (i.e., no heat loss or gain), the adiabatic combustion temperature can be determined. 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]] is used entirely for heating the fuel, the combustion air or oxygen, and the combustion product gases (commonly referred to as the ''[[flue gas]]'').

In the case of [[fossil fuels]] burnt in air, the combustion temperature depends on all of the following:
* the [[Heat of combustion|heating value]];
* the [[air-fuel ratio|stoichiometric air to fuel ratio]] <math>{\lambda}</math>;
* the [[specific heat capacity]] of fuel and air;
* the air and fuel inlet temperatures.

The adiabatic combustion temperature (also known as the ''[[adiabatic flame temperature]]'') increases for higher heating values and inlet air and fuel temperatures and for stoichiometric air ratios approaching one.

Most commonly, the adiabatic combustion temperatures for coals are around {{convert|2200|C|0|abbr=on}} (for inlet air and fuel at ambient temperatures and for <math>\lambda = 1.0</math>), around {{convert|2150|C|0|abbr=on}} for oil and {{convert|2000|C|0|abbr=on}} for [[natural gas]].<ref>{{cite journal | title = Adiabatic flame temperature | journal = Industrial Heating | page = 20 | date = May 2013 | url =  http://www.industrialheating.com/articles/91062-adiabatic-flame-temperature | access-date = 5 July 2013}}</ref><ref name="AFTCalc">[http://www.industrialheating.com/AFT-Calc] AFTCalc</ref>

In industrial [[Industrial furnace|fired heaters]], [[power station]] [[steam generator]]s, and large [[gas turbine|gas-fired turbines]], the more common way of expressing the usage of more than the stoichiometric combustion air is ''percent excess combustion air''. For example, excess combustion air of 15 percent means that 15 percent more than the required stoichiometric air is being used.