An Experimental Investigation On Coal Particles Combustion of Subbituminous Coals in Different Oxygen Concentration Conditions

Oxy-coal combustion is a promising alternative to achieve carbon dioxide capture and clean coal technology which could be directly applicable to the conventional pulverized coal fired utility power plants. In line with this, an 100MWe oxy-combustion power station project was launched in Korea 2007. For successful installation and operation of such facility, it is essential to understand the coal combustion mechanism under unconventional conditions in which the characteristic of pulverized coal combustion under oxy-coal combustion is quite different from that of air-blowing atmosphere. In this study, the characteristic of coal combustion mainly on devolatilization and char combustion, were investigated through flame lengths. The effects of oxygen mole fraction in N₂ and CO₂ diluent gases respectively, particle sizes for sub-bituminous coals were studied in a laminar flow entrained reactor that produces similar environment of utility furnace in terms of high heating rate and temperature. O₂ mole fraction was varied 0~50%. The flame length becomes shorter as increase of O₂ concentration. It means that the reactivity in both devolatilization and char oxidation process is increased in higher O₂ concentration environment. The char particles' burnout time with increase of O₂ fraction becomes shorter but there is not much difference between those of O₂/N₂ and O₂/CO₂ environments.