Nucleation properties of respirable coal dust: terminal progress report.
Schowengerdt-FD; Brown-JT Jr.
NIOSH 1978 Jan; :1-73
A series of studies on the interaction of respirable coal dust with water vapor was conducted to investigate the nucleation and subsequent growth of water droplets on respirable coal dust particles and to determine the effect of particle properties and environmental factors on the nucleation and growth rates. A continuous flow thermal diffusion cloud chamber (spectrometer) was used to observed nucleation and growth of water droplets in the presence of coal dust, and measurements were taken of growth of water droplets on particulates in real time and as a function of supersaturation and residence time, and of the nucleation efficiencies for water vapor on coal dust. It was found that nucleation and growth of water droplets to sizes of several microns on coal dust in the respirable size range occured under conditions of moderate supersaturation in times of less than 3 seconds. The nucleation efficiency of respirable coal dust towards water vapor was found to be almost 100% during moderate supersaturation. It is concluded that the results serve to eliminate most of the uncertainties regarding the use of nucleation and condensation as a technique to improve water sprays used in elimination of respirable particles from coal mines. It is suggested that droplet growth measurements would be useful in any problem involving interactions between particulates and water vapor, such as dust elimination, pollutant washout in precipitation, and inhalation toxicology.
NIOSH-Grant; Dust-control; Dust-analysis; Dusts; Particulate-dust; Environmental-control; Mining-industry; Analytical-methods
Physics Colorado School of Mines Department of Engr Physics Golden, Colo 80401
Final Grant Report
NTIS Accession No.
NIOSH, Cincinnati, Ohio, Final Report
Colorado School of Mines, Golden, Colorado