Effect of Steam on Ignition of Pulverized Coal Particles in Oxy-Fuel Combustion in a Drop Tube Furnace

Abstract

The substitution of CO2 by 5%, 10%, 20%, and 30%, steam was implemented to evaluate the effect of the mole fractions of steam on the ignition of coal in O2/CO2/H2O atmospheres with the oxygen mole fractions of 21%,, 30%, and 40%, by using experimental and numerical methods. The experimental results reveal that the ignition distances are barely affected when the low mole fraction of steam (5%, 10%, and 20%,)was added to O2/CO2 atmospheres. As the mole fraction of steam was increased to 30%,, the ignition distance was significantly decreased. The numerical results indicate that the physical properties of steam lead to the ignition delay of coal while its chemical properties are beneficial to the ignition.