A Statistical Study of Coal Sulfur Variability and Related Factors

摘要

Coal analysis data ad power plant continuous monitoring data were gathered, reviewed and analyzed to assess the impact of fuel coal characteristics on compliance strategies and emission regulations. Coal analysis data, on a raw and washed basis, were analyzed by individual mine, composite coal seams and USBM Producing Districts. The results indicated that composite coal seam or Producing District data cannot be used to accurately predict sulfur variabilities for individual mines. Analyses indicated that the heat content (Btu/lb) was best approximated by the normal distribution, which the sulfur content and pounds sulfur/MMBtu were best represented by the inverted gamma distribution which was slightly superior to the lognormal distribution. Analysis of available continuous monitoring data supported the inverse relationship between coal sulfur variability and lot size, i.e., significant reductions in relative variability of emissions occur as the averaging time increases. The continuous monitoring data indicate that while FGD systems reduce mean emission levels, the relative variabilities of outlet SO2 concentrations are substantially greater than those of inlet SO2 concentrations. The various analyses of coal sulfur variability identified no reliable method for coal suppliers or consumers to predict variability which may be critical for compliance by some coal-fired boilers to existing sulfur emission-limiting regulations.