Emission factors for fugitive dust from bulldozers working on a coal pile

Abstract

A study of a Powder River Basin (PRB) coal pile found that fugitive emissions from natural and human activity each produced similar levels of downwind fine + coarse (i.e., smaller than 10 µm, or PM 10 ) particle mass concentrations. Natural impacts were statistically removed from downwind measurements to estimate emission factor E v for bulldozers working on the pile. The E v determined here was similar in magnitude to emission factors (EFs) computed using a U.S. Environmental Protection Agency (EPA) formulation for unpaved surfaces at industrial sites, even though the latter was not based on data for coal piles. EF formulations from this study and those in the EPA guidance yield values of similar magnitude but differ in the variables used to compute E v variations. EPA studies included effects of surface silt fraction and vehicle weight, while the present study captured the influence of coal moisture. Our data indicate that the relationship between PRB coal fugitive dust E v (expressed as mass of PM 10 emitted per minute of bulldozer operation) and coal moisture content M c (in percent) at the study site is best expressed as E v =10 f(M c ) where f(M c ) is a function of moisture. This function was determined by statistical regression between log 10 (E v ) and M c where both E v and M c are expressed as daily averages of observations based on 289 hours sampled during 44 days from late June through mid-November of 2012. A methodology is described that estimates M c based on available meteorological data (precipitation amount and solar radiation flux). An example is given of computed variations in daily E v for an entire year. This illustrates the sensitivity of the daily average particulate EF to meteorological variability at one location. Finally, a method is suggested for combining the moisture-sensitive formulation for E v with the EPA formulation to accommodate a larger number of independent variables that influence fugitive emissions.Implications: Fugitive coal dust emission factors (EFs) derived by this study contribute to the small existing knowledge base for a type of pollutant that will become increasingly important as ambient particulate standards become tighter. In areas that are not in attainment with standards, realistic EFs can be used for compliance modeling and can help identify which classes of sources are best targeted to achieve desired air quality levels. Reconciling emission factor formulations that are sensitive to different factors (i.e., those from the EPA and this study) produces a more powerful tool for estimating fugitive emissions at a broad range of sources.

Reducing Environmental Impact of Coal-Fired Power Plants by Building an Indoor Coal Storage: An Economic Analysis

“…Kim et al [19] studied the PM 10 emissions from a coal storage yard in a thermal power plant. Their results revealed that PM 10 emissions from coal yards were affected by several factors, including dust control measures, weather conditions, and the method and timing of coal loading and unloading.…”

Mesoscale behavior study of collector aggregations in a wet dust scrubber

“…However, their fine-dust removal efficiency is relatively low, amounting to 50.3% for dust particles of 0.5 μm in size (Ma and Jia, 2007), as compared with that of 62.48% for 0.25-μm-sized particles provided by a turbulent wet scrubber with a feed rate of 140 mg/min in a gas flow of 3.5 m 3 /min and a water level of 58 cm (Byeon et al, 2012). Currently, the studies of selfexcited dust scrubbers are mainly focused on the dust removal efficiency, pressure drop characteristics, dust removal liquid additives (modification of surface structure of dust removal liquid molecules), and two-phase flow patterns (Dullien and Munro, 1973;Li et al, 2016b;Hadlocon et al, 2015;Khan et al, 2016;Mueller et al, 2015), addressing either macroscopic (dust scrubber) or microscopic (dust removal liquid molecules) levels with no account of the interface phenomena occurring in between these levels. This gap was filled with the development of mesoscale approach (Charpentier, 2002;Fiore et al, 2015;Ge et al, 2011;Shaffer et al, 2013;Li et al, 2010), the application of which to self-excited dust scrubbers is expected to yield more insight into their dust removal mechanism and theoretically substantiate the required technological innovations for improving the dust removal efficiency.…”