SPECTROSCOPIC INVESTIGATIONS ON METHANE AIR FLAMES CONTAINING COAL DUST

Recently the possibility has been proposed that a natural gas-coal mixture can be used to replace oil in an existing oil boiler. In order to study the physical and chemical effects of combining methane and coal dust in a flame, a spectroscopic investigation of methane-air and methane-air-coal dust flames was initiated. A laboratory burner with suitable flow controls was adapted for the simultaneous combustion of methane-air-coal dust mixtures. Pulverized bituminous coal dust ((TURN)200 mesh) was introduced into this burner by means of a fluidized bed device which allowed for a steady and reproducible amount of coal dust to be input to the flame.;Spectral emission profiles of the primary reaction zone for the radicals OH, CH and C(,2) were obtained and results are discussed in relation to excited state formation mechanisms. Current ideas on the chemical and physical processes occurring in methane-air flames are reviewed along with current knowledge of coal and its combustion. Data from the present study are compared to literature data and chemical and physical mechanisms are proposed to account for these observations.;Spectral emissions from radical species OH, CH, and C(,2) were measured along with CO emissions which were then used to calculate excited state species number densities. Methane-air flames of various equivalence ratios were studied along with stoichiometric, lean and rich methane-air-coal dust flames. Emission intensities were obtained as a function of height in the various flames and differences between the methane-air and methane-air-coal dust flames are discussed. Spatial temperature measurements of these flames were also obtained.