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'''Minimum ignition energy (MIE)''' is the minimum amount of energy required to ignite a combustible vapor, gas or dust cloud, for example by means of an [[electrostatic discharge]]. Ignition of a fuel/air mixture is possible only when the rate of liberation of heat near the ignition zone is greater than the heat loss by conduction. Heat loss due to radiation is not considered, as it is assumed to be negligible, and the ignition process is assumed to be steady and one-dimensional{{clarifyme}}. MIE is measured in [[joules]] (J).<ref>Pratt, Thomas H. "Electrostatic Ignitions of Fires and Explosions" Wiley-AIChE (July 15, 1997) Center for Chemical Process Safety</ref>
'''Minimum ignition energy (MIE)''' is the minimum amount of energy required to ignite a combustible vapor, gas or dust cloud, for example by means of an [[electrostatic discharge]]. Ignition of a fuel/air mixture is possible only when the rate of liberation of heat near the ignition zone is greater than the heat loss by conduction. Heat loss due to radiation is not considered, as it is assumed to be negligible, and the ignition process is assumed to be steady and one-dimensional{{clarifyme|date=December 2012}}. MIE is measured in [[joules]] (J).<ref>Pratt, Thomas H. "Electrostatic Ignitions of Fires and Explosions" Wiley-AIChE (July 15, 1997) Center for Chemical Process Safety</ref>


[[Explosive]]s, [[hydrogen]], [[unsaturated hydrocarbon]]s and [[alkane]]s in oxygen have the lowest MIE: in the range of 1 to 100 μJ. Alkanes in air, distillate fuels, hybrid mixtures and extremely sensitive dusts have a MIE range of 0.1 to 10 mJ. Combustible dusts have a MIE range of 0.01 to 10 J.
[[Explosive]]s, [[hydrogen]], [[unsaturated hydrocarbon]]s and [[alkane]]s in oxygen have the lowest MIE: in the range of 1 to 100 μJ. Alkanes in air, distillate fuels, hybrid mixtures and extremely sensitive dusts have a MIE range of 0.1 to 10 mJ. Combustible dusts have a MIE range of 0.01 to 10 J.

Revision as of 17:38, 18 December 2012

Minimum ignition energy (MIE) is the minimum amount of energy required to ignite a combustible vapor, gas or dust cloud, for example by means of an electrostatic discharge. Ignition of a fuel/air mixture is possible only when the rate of liberation of heat near the ignition zone is greater than the heat loss by conduction. Heat loss due to radiation is not considered, as it is assumed to be negligible, and the ignition process is assumed to be steady and one-dimensional[clarification needed]. MIE is measured in joules (J).[1]

Explosives, hydrogen, unsaturated hydrocarbons and alkanes in oxygen have the lowest MIE: in the range of 1 to 100 μJ. Alkanes in air, distillate fuels, hybrid mixtures and extremely sensitive dusts have a MIE range of 0.1 to 10 mJ. Combustible dusts have a MIE range of 0.01 to 10 J.

For most materials, the lowest ignition energy value occurs at a concentration near the midpoint between those for the lower flammable limit (LFL) and the upper flammable limit (UFL). [2]

See also

References

  1. ^ Pratt, Thomas H. "Electrostatic Ignitions of Fires and Explosions" Wiley-AIChE (July 15, 1997) Center for Chemical Process Safety
  2. ^ NFPA 77 – 2007: page 20