What is the minimum ignition energy?
The minimum ignition energy (MIE) is the lowest amount of energy mediated by an electric spark that ignites dispersed fuel or otherwise combustible compounds in the air. The conditions must be ideal for an explosion with MIE values, but otherwise only slightly higher ignition values may be necessary. The spark that causes an explosion in such cases can either be from an electrostatic discharge (ESD) where there is a latent difference in the electrical potential between two objects in close proximity, or may be caused by a living electrical circuit that experiences an arc or short circuit. Understanding chemical combustion processes leading to minimal ignition energy events is important in the area of firefighters and industries, which include storage and use of volatile compounds, for example in the operation of aircraft.
Saint fuel and solvents and other chemicals that are aboutIt is known that they have very low minimum ignition energy values, include acetylene and hydrogen at 0.017 millionyle, ethylene to 0.08 million and methane at 0.3 millionjle. These chemicals must be solved with extreme care in limited spaces due to the fact that all of them also have low evaporation points at normal atmospheric pressure and temperature. One of the most challenging and deadliest of the American commercial air accidents, years TWA 800 12 minutes after take -off from New York, New York, July 1996, was attributed to a possible ignition energy explosion in the center wing fuel tank. About 50 gallons (189 liters) of air fuel known as Jet A, which was stored in the tank at that time, was unintentionally heated by air -conditioning units directly below the reservoir, which eliminated part of the fuel. As the plane rose at an altitude, the reduced air pressure increased evaporation to the extent that the overpressure and the trial state of the spark created an explosion that broke the fuel tank itself and destroyed the aircraft.
Several other types of compounds that are dispersed in the air as fine particles, from powdered metals to cereal flour and solid fuels such as coal and sulfur, and also tend to have low minimum ignition values. MIE for aluminum is 15 millionales and magnesium is 40 million. Coal ranges from 30 to 60 millionhouls and grain flour is ignited at 240 million. Dust explosion can even occur with a random mixture of floor residues swept into the air, if it is well dispersed in a heated environment, with the potential to ignite in the range of 0.2 million to 10 joul, if the humidity is below 80% and the ambient temperature is 59 ° to 77 ° Fahrenheit).
Other compounds known to have low minimum ignition values below 1 Millioule are fuels of the propane, iron dust and carbonisulphide. These low values are significant compared to the energy level generated from common spark sources. Static Electric Spark usually releases about 22 milesIjjouls of energy and a spark plug in the car will release about 25 million -dollar energy with each cycle of combustion.