Here is an interesting global update with a dust explosion (staubexplosion) at a wood pellet mill in Ettenheim, Germany that occurred January 4. Use the Google Toolbar to translate from German to English for the rest of the story, as Paul Harvey would say. It's interesting to note how well versed the news reporter is in reporting that a dust explosion occurred while providing readers detailed information about the process equipment where the explosion originated, the hammer mill.
Last year in the United States, nearly a half a dozen combustible dust related fires and explosions occurred in wood pellet plants within a short time span of three months. Of the over 150 combustible dust related explosions and fires that the Combustible Dust Policy Institute found through media reports in 2008 at manufacturing facilities, most of the time there's never a headline like in the German online article where the incident was actually a dust explosion (staubexplosion). Instead in our regional news, readers must carefully search for key words as the reporter describes the fire or explosion. Such as a fire in the ductwork or explosion in the dust collector.
An exception to news reporting of dust explosions in the United States occurred January 20, 2009 when news reporter Cara Spoto of the Freeport, Illinois Journal Standard, reported on the dust explosion at an Ethanol plant in Monroe, Wisconsin. One does not easily find news reports like this describing the event in such detail and even mentioning the dryer. Quite similiar to the mention of the hammer mill in the German wood pellet mill dust explosion
Most revealing, the term deflagration (verpuffung), was used three times in the informative article. A deflagration is rapid subsonic combustion where there is also a rapid rise in pressure and heat. There's good deflagrations, like the reusable solid rocket boosters when the Space Shuttle launches with the assistance of over 320,00 lbs of micronized aluminum dust and of course there is bad deflagrations that we sometimes read about in the news with dust explosions occuring in a diverse spectrum of industry.
Many fires and explosions that occur in the manufacturing and non-manufacturing sectors that are combustible dust related never get reported as such, since reporters and the general public are not yet knowledgeable about deflagrations. It's difficult enough to say the word without getting tongue tied. Much less acknowledge that products on the supermarket aisle, so harmless as milk powder and dairy creamer can level a production facility, causing fatalities and injuries.
German research scientists have been studying dust explosions for over a century and have assisted their global trading partners with the wealth of knowledge they have acquired. Check out the GESTIS-DUST-EX database on the German BGIA - Institute for Occupational Safety and Health website for ignition sensitivity and explosion severity data of more than 4,000 dust samples from a multitude of sectors.
Its interesting to note that the deflagration index Kst, in regards to testing for explosion severity in the laboratory also has German roots, as the subscript (st) denotes staub, the German word for dust, thus staubexplosion. So remember next time you turn the ignition with your keys to start your car, your having a good verpuffung when the fuel-air mixture in your engine ignites creating a good deflagration transforming chemical energy into useful mechanical energy for the daily commute to work or run errands in town.
Friday, January 23, 2009
Staubexplosion German Pellet Mill
Labels:
deflagration,
staubexplosion,
verpuffung,
wood pellet
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