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Show STATEMENT OF THE PROBLEM As a prelude to the presentation of the details of the singular pulverized coal combustion program specifically designed to address this situation, it is important to note that some intelligent qualitative information can be and has been derived on the problem of unifying coal combustion characteristics. From a proper understanding and interpretation of the voluminous data available in the literature, it is possible, to some extent, to estimate or predict physical [ignition and burnout times] and chemical [pollutant emissions] combustion behavior from a coal's compositional properties, i.e., its ultimate and proximate analyses. Table I lists some "typical" compositions of selected and conventional alternative solid fuels. Conventional wisdom states that the ease of ignition of a powdered fuel is, to a great extent, a function of the percent volatile matter: broadly speaking, the higher the percent 2 coal volatile matter, the more readily the pulverized fuel will ignite. Moreover, from decades of pulverized fuel combustion research, there is unwritten "rule of thumb" that states that coals having a volatile matter content of 20-23% or greater will offer no ignition or stability problems, whereas those having less than these amounts may very well be troublesome. Several years ago, Cogoli, et al., experimentally verified that ignition and stability were not exclusively critically-dependent upon coal rank, and made the claim that, "reactivity is not conferred by volatile matter." Because char reactivity dramatically increases 3 with decreasing coal rank, as does volatile matter, any decoupling is difficult. It should also be pointed out that combining high volatilities with high moisture contents can give rise to exceptions to the aforementioned rule of thumb, as for low-rank coals (lignites) and coal precursors (peats). Burnout efficiency is a complex function of many compositional variables, with reactivity and the amount of fixed carbon playing significant roles: crudely speaking, the lower the reactivity and the higher the fixed carbon, the more likely it is for carbon oxidation to be incomplete within the residence time of the combustor and for carbon particulate carry-over to result. Finally, an evaluation of a solid fuel's combustion-generated air pollution potential can be made by inspection of its ultimate analysis: the higher the percent fuel-nitrogen, -sulfur, 17-3 |