COMBUSTION REACTIVITY OF SMOKY-RIVER COAL-MINE BY-PRODUCTS

H. R. Milner Generating Station of Alberta Power Limited (145-MW capac ity, down-shut firing mechanism of Combustion Engineering Ltd) utilize s the by-products of the Smoky River coal (low-volatile bituminous) mi ne. These by-products are composed of run-of-mine, tailings, and rejec ts. High-ash, low-volatile matter content and low char combustion reac tivity cause low carbon burnout and low flame stability, and high auxi liary fuel consumption. To improve combustion efficiency of the genera ting station, combustion reactivity tests were conducted using a therm ogravimetric analyzer and a laminar drop tube reactor. In addition, th e microscopic characteristics of the coal! bottom ash, and fly ash wer e also studied. Some of the chars formed from vitrinite, causing low c ombustion reactivity. Particle size, gas temperature, and oxygen parti al pressure have an effect on the apparent rate of coal combustion. Ch ar combustion rate is controlled by oxygen diffusion. Combustion effic iency could be improved by increasing turbulence intensity in the furn ace, by blending the coal with a more reactive fuel, or by reducing th e ash content of the coal.