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VARIABILITY AND CORRELATION IN RAW AND CLEAN COAL: MEASUREMENT AND ANALYSIS
Citation:
Cheng, B., K. Crumrine, A. Gleit, A. Jung, AND D. Sargent. VARIABILITY AND CORRELATION IN RAW AND CLEAN COAL: MEASUREMENT AND ANALYSIS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/7-83/055.
Description:
The report gives results of the evaluation of coal samples, collected at 1/2- or 1-hour intervals from the inlet to, and outlet from, two coal preparation plants. (The ability of a coal to comply with an emission regulation depends on the statistical characteristics of the coal sulfur content and heat content and the requirements of the regulation. Previous studies of the ability of coal to comply with emission regulations have been hampered by inadequacies in the coal data sets which can be used to statistically characterize the variations in coal properties.) The samples were analyzed for total sulfur, pyrite sulfur, heating value, ash content, and moisture. Values for organic sulfur and SO2 emissions (lb SO2/million Btu) were calculated. Data were evaluated statistically to determine the mean value, variance, relative standard deviation (standard deviation divided by mean), correlation structure, and skewness. Coal cleaning at the plants reduced the mean SO2 emission parameter by about 23 and 63 percent, respectively. The relative standard deviation (RSD) of the SO2 emissions were reduced by 26 and 44 percent, respectively. Differences in the reductions in mean and RSD values between plants resulted primarily from differences in raw coal properties. Model results show the importance of considering the effects of auto-correlations when estimating the potential for exceedance with raw or clean coal.