Quantitative measurement and indication of pulverized coal ignition temperatures in O2/CO2 environments

The method on quantitative determination of the ignition condition of pulverized coal particles in a laminar drop tube furnace (DTF) was proposed with the continuous measurement of the evolved oxygen concentration in flue gas at variable furnace wall temperatures. Then the method was adopted to quantitatively determine the coal ignition temperatures in different O2/CO2 and air environments for five coal ranks with the measurement of the separate axial temperature profiles in the furnace centerline with and without coal particles feeding. The result shows that the coal ignition temperature in 21%O2/79%CO2 environment measured by DTF method is higher than that in air environment for each coal rank. Moreover, the coal ignition temperature significantly decreases with the increasing oxygen partial pressure in O2/CO2 environments, and the coal ignition temperature in O2/CO2 environment can match that in air environment when the oxygen partial pressure is increased to the value ranging from 25.8% to 44.1%, which is relative to different coal ranks.