Minimum ignition energy: Difference between revisions
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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 due to an [[electrostatic discharge]]. 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 due to an [[electrostatic discharge]]. Ignition of a fuel air mixture is possible only when the rate of liberation of heat near the ingnition zone is greater than or equal to the heat loss by conduction, thus ignition energy balances the heat loss by conduction. this is known as Minimum Ignition Energy. It must be noted that heat loss due to radiation is not considered and the ignition process is assumed to be staedy and one-dimensional. 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> |
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[[Explosive]]s, [[hydrogen]], [[unsaturated hydrocarbon]]s and [[alkane]]s in oxygen have the lowest MIE – range of {{e|-3}} to {{e|-1}} (mJ). Alkanes in air, distillate fuels, hybrid mixtures and extremely sensitive dusts have a MIE range of {{e|-1}} to {{e|1}} (mJ). Combustible dusts have a MIE range of {{e|1}} to {{e|4}} (mJ). |
[[Explosive]]s, [[hydrogen]], [[unsaturated hydrocarbon]]s and [[alkane]]s in oxygen have the lowest MIE – range of {{e|-3}} to {{e|-1}} (mJ). Alkanes in air, distillate fuels, hybrid mixtures and extremely sensitive dusts have a MIE range of {{e|-1}} to {{e|1}} (mJ). Combustible dusts have a MIE range of {{e|1}} to {{e|4}} (mJ). |
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Revision as of 03:37, 20 March 2012
Minimum ignition energy (MIE) is the minimum amount of energy required to ignite a combustible vapor, gas or dust cloud, for example due to an electrostatic discharge. Ignition of a fuel air mixture is possible only when the rate of liberation of heat near the ingnition zone is greater than or equal to the heat loss by conduction, thus ignition energy balances the heat loss by conduction. this is known as Minimum Ignition Energy. It must be noted that heat loss due to radiation is not considered and the ignition process is assumed to be staedy and one-dimensional. MIE is measured in joules (J). [1]
Explosives, hydrogen, unsaturated hydrocarbons and alkanes in oxygen have the lowest MIE – range of ×10−3 to ×10−1 (mJ). Alkanes in air, distillate fuels, hybrid mixtures and extremely sensitive dusts have a MIE range of ×10−1 to ×101 (mJ). Combustible dusts have a MIE range of ×101 to ×104 (mJ).
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]