Skip directly to search Skip directly to A to Z list Skip directly to page options Skip directly to site content

NIOSHTIC-2 Publications Search

Search Results

The Flammability of Coal Dust-air Mixtures. Lean Limits, Flame Temperatures, Ignition Energies, and Particle Size Effects.

Authors
Hertzberg-M; Cashdollar-KL; Opferman-JJ
Source
NTIS: PB 299 521 :70 pages
Link
NIOSHTIC No.
10000429
Abstract
A comprehensive study of the flammability behavior of air-dispersed coal dust was made using an 8-liter Bureau of Mines system which included the following: (1) an optical probe to continuously monitor the dust concentration; (2) measurements of ignition energy requirements; (3) the use of several narrow size distributions ranging from 3 to 65 um average diameter; (4) measurements of the extent of flame propagation based on pressure attained at constant volume, residual o2 content after combustion, and flame and dust surface temperatures. The measured lean limit for near-horizontal propagation of Pittsburgh coal dust was about 135 mg/l (milligrams per liter), virtually independent of particle size. Required ignition energies were hundreds of joules and measured limit flame temperatures were 1,450 to 1,600 k. Data on inerting requirements with khco3, rock dust, and nacl gave approximately the same results as full-scale explosion tests. The good agreement suggests that the cause of earlier discrepancies between small-scale laboratory data and full-scale mine experiments may not have been the difference in size, but were rather a problem of proper care in isolating and controlling the significant experimental variables and in consistently defining the extent of flame propagation at the limits.
Publication Date
19790101
Document Type
IH; Report of Investigations
Fiscal Year
1979
NTIS Accession No.
PB-299521
NTIS Price
A05
Identifying No.
RI 8360
NIOSH Division
PRC;
Source Name
NTIS: PB 299 521
TOP