Effects of carbon content in coal on flame radiation in large-scale pulverized-coal-fired boiler furnaces

Measurement of flame radiation has been done in a 1025 t/h pulverized-coal-fired boiler furnace. The flame emissivity, temperature and radiative energy of a cross-section upon the burners have been calculated using visible image processing technique. The fuel was four types of anthracite. Experimental results show that, in the same furnace load, the flame emissivity increased with the increase of carbon in coals, while the temperatures in the furnace changed slightly with the increase of carbon in coals. In addition, the radiative energy calculated by visible image processing varied with the change of coal, so the effect of coal rank should be considered when the radiative energy in the visible spectrum is used in combustion control.