Flame temperature
The flame temperature is the temperature that can be measured inside the flame during combustion.
It must not be confused with the variables ignition temperature , flash point or heat of combustion .
The flame temperature depends on the degree of mixing of the flammable gases, the nitrogen and oxygen content of the gas mixture, the pressure and preheating of the gases and the design of the burner. As a rule, there are different areas within a flame, the temperatures of which can differ by a few hundred Kelvin.
The literature usually states the highest temperature that can be measured in a flame under ideal conditions. Examples:
| fuel | Flame temperature | |
|---|---|---|
| with air | with pure oxygen | |
| Propane / butane | 1925 ° C | 2850 ° C |
| hydrogen | 2130 ° C | 3080 ° C |
| Methane ( natural gas ) | 1970 ° C | 2860 ° C |
| Ethyne (acetylene) | 2250 ° C | 3030 ° C |
The fact that a lower flame temperature is reached with air than with pure oxygen is primarily due to the fact that the nitrogen contained has to be heated. In addition, the formation of nitrogen oxides requires heat as an endothermic reaction, which cools the burner flame.
In addition, in order to achieve a high flame temperature, it must be taken into account that a pressurized gas cools down during expansion due to the Joule-Thomson effect and therefore gas preheating is sometimes necessary.
The reaction of hydrogen with fluorine reaches about 4000 ° C, one of the highest flame temperatures under normal pressure
Web links
- Thomas Sattelmayer: Combustion: Material flows and adiabatic flame temperature. (No longer available online.) Archived from the original on January 7, 2014 ; accessed on July 12, 2016 (calculation procedures necessary for the combustion calculation in the form of self-sufficient HTML files).
- pangas.ch: LPG propane C 3 H 8 (compressed, liquefied under pressure) (PDF; 90 kB)
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- ^ F. Henning: Temperature measurement . ISBN 978-3-642-81139-5 , pp. 346 ( google.de ).