| The results of a comprehensive and systematic research program on coal-derived liquid fuel (CDL) combustion using The Pennsylvania State University Fuels and Combustion Laboratory hot-wall process furnace are reported. This study represents the first time flames of these alternative liquid fuels have been characterized with such a device. The physical (ignition characteristics; flame color, length, and shape; thermal efficiency; heat flux; roof, wall, and exhaust gas temperature profiles; and heat balance closures), and chemical (CO(,2), CO, O(,2), NO(,x), smoke, and particulate concentrations) properties of two coal liquid fuels {H-Coal and Solvent Refined Coal (SRC-II) blend} and one petroleum oil (No. 2) were determined at varying excess air levels ((+OR-)30%), at constant firing rate (300 kilowatts (KW) and atomizing air pressure (530 KN/m('2)). The major thrust of this program was to determine the suitability of substituting the coal liquids for the petroleum-derived liquid (PDL).;The ignition behavior, length, and shape of both the CDL and PDL flames were reasonably comparable. NO(,x), CO, smoke, and particulate emissions, heat fluxes and thermal efficiencies were higher for the CDL fuels than for the PDL one under identical operating conditions. However, the position of the maximum heat absorption (hot-spot) was closer to the burner for the coal liquids. Reductions in NO(,x) and fuel-nitrogen-to-NO(,x) conversion were optimal at -12% excess air for CDL whereas no such maximum was observed for the PDL. Extensive correlations were derived between major fuel properties and combustion characteristics. These will be valuable in predicting the combustion of second-generation coal-derived liquid fuels. |
