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While engineered nanomaterials include uniquely manufactured products with unique shapes and enhanced physical and chemical properties, little information is currently available on the explosion risks of nanoparticles. Besides, the little data that does exist is contradictory and suggests the explosion violence is less than that of larger particles, which is contradictory to the fact that fine powders are known to be an explosion risk, particularly organic and metallic powders. Standard test equipment to determine the explosion and ignition characteristics for fine particulates typically require kilogram quantities of powder. And many nanopowders, due to their large surface to volume ratio, are spontaneously flammable on contact with air, or surface oxidation alters their properties. Hence for investigation equipment is required that avoids oxidation until the point of ignition. In a research project commissioned by HSE (Health and safety Executive) and partly funded by the HSL (Health and Safety Laboratory) Internal Research Programme specialised equipment and techniques were developed and existing equipment modified to measure the explosion and ignition characteristics of a range of nanopowders including metal and organic nanopowders. Examples of equipment are the minimum ignition energy test apparatus and a special dust container and a dust dispersion chamber. Test materials were aluminium, multiwalled carbon nanotubes, carbon nanofibres, iron zinc, copper, and lycopodium micropowder. Diagrams show the explosion pressures and rates of pressure rise of these powders in 2 l spheres for concentrations between about 40 g/m3 or about 100 g/m3 or only about 200 g/m3 as the lower limit and up to about 1500 g/m3 or up to about 2000 g/m3 or even up to 6000 g/m3 (for aluminium nanopowders). Maximum explosion pressures of up to 12.5 bar/g and maximum rates of pressure rise of up to 2000 bar/s were measured.
While engineered nanomaterials include uniquely manufactured products with unique shapes and enhanced physical and chemical properties, little information is currently available on the explosion risks of nanoparticles. Besides, the little data that does exist is contradictory and suggests the explosion violence is less than that of larger particles, which is contradictory to the fact that fine powders are known to be an explosion risk, particularly organic and metallic powders. Standard test equipment to determine the explosion and ignition characteristics for fine particulates typically require kilogram quantities of powder. And many nanopowders, due to their large surface to volume ratio, are spontaneously flammable on contact with air, or surface oxidation alters their properties. Hence for investigation equipment is required that avoids oxidation until the point of ignition. In a research project commissioned by HSE (Health and safety Executive) and partly funded by the HSL (Health and Safety Laboratory) Internal Research Programme specialised equipment and techniques were developed and existing equipment modified to measure the explosion and ignition characteristics of a range of nanopowders including metal and organic nanopowders. Examples of equipment are the minimum ignition energy test apparatus and a special dust container and a dust dispersion chamber. Test materials were aluminium, multiwalled carbon nanotubes, carbon nanofibres, iron zinc, copper, and lycopodium micropowder. Diagrams show the explosion pressures and rates of pressure rise of these powders in 2 l spheres for concentrations between about 40 g/m3 or about 100 g/m3 or only about 200 g/m3 as the lower limit and up to about 1500 g/m3 or up to about 2000 g/m3 or even up to 6000 g/m3 (for aluminium nanopowders). Maximum explosion pressures of up to 12.5 bar/g and maximum rates of pressure rise of up to 2000 bar/s were measured.
Explosion properties of nanopowders
Holbrow, P. (Autor:in)
2009
9 Seiten, 13 Bilder, 7 Tabellen, 5 Quellen
Aufsatz (Konferenz)
Datenträger
Englisch
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