- Author
-
Grumer, J.
|
Bruszak, A. E.
- Title
- Inhibition of Coal Dust-Air Flames.
- Coporate
- Bureau of Mines, Pittsburgh, PA
- Report
-
RI 7552,
August 1971,
18 p.
- Distribution
- Available from National Technical Information Service
- Keywords
-
coal dusts
|
coal mines
|
inhibitors
|
monnex (trademark)
|
flame speed
|
flame propagation
|
wall temperature
|
halons
|
Purple K
- Identifiers
- wall quenching; rock dust
- Abstract
- Nine dust and gaseous inhibitors of propagating coal dust-air flames (lean, stoichiometric, and rich) were evaluated in a newly developed 15-cm-id, 3.6-meter-long instrumented flame duct, under conditions such that wall quenching was virtually absent and the dust concentration was temporally and spacially uniform to within about ±5 percent. Listed roughly in order of increasing efficiency, the inhibitors evaluated were rock dust (calcium carbonate), powdered oyster shells (calcium carbonate), Halon 1301 (trifluorobromomethane), Halon 1211 (difluorochlorobromomethane), sodium chloride, Super-K (potassium chloride), regular-grade fire extinguishant powder (sodium bicarbonate), Purple-K (potassium bicarbonate), and Monnex (potassium bicarbonate combined with urea). Experiments were extended to clouds containing 1 and 2 volume-percent of methane. The inhibition of lean, scoichiometric, and rich methane-air flames without coal dust was also examined in a few instances; results agreed with those obtained for coal dust-air flames.