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Show COAL COMBUSTION IN FUEL RICH FLAMES: A REVIEW OF EXPERIMENTAL BEHAVIOR 1. INTRODIJCTION In this paper we present a summary of experimental results for th e profiles of combustion efficiency and temperature as functions of stoichiometry , during combustion of coal in fuel rich flames. The data were obtained in a series of experiments [1-11] using two different reactors/furnaces. The results support the long-held view that "optimum" combustion conditions occur at some equivalence ratio greater than unity (fuel-rich conditions), and close to the stoichiometric conditions for (true) volatiles combustion. Reasons for interest in fuel rich flames are essentially practical. There are two conditions of major importance: initiation of combustion in a fuel-rich primary jet in p.c. firing of a boiler or a furnace; and explosive combustion of a rich mixture in a mill or conveying line. In both cases there is interest in and the two properties: limit conditions the maximum explosive or reactivity conditions; (rich and lean). research has certainly emphasized behavior in fuel rich Dust explosion conditions, but emphasis has been rather on determining explosion and ignition limit conditions than on developing a coherent data base suitable for analysis, fundamental interpretation, and extrapolation of the results to the practical conditions of interest. The more fundamental reactivity studies outside dust explosion research, on the other hand, have generally emphasized fuel-lean combustion in flame investigations, or have been carried out in drop-tube or similar dilute-phase experiments where the relation of such data to flame behavior is uncertain, particularly in fuel-rich combustion. Thus we have the situation that there is something of a plethora of information on combustion behavior for single particles, or in dilute streams, or (marginally) in small, lean flames; but, information under fuel rich |