Numerical Study of Pulverized Coal Ignition Characteristics under O_2/CO_2 Atmosphere

摘要

O_2/CO_2 combustion of pulverized coal is one of the promising new technologies in order to reduce the emission of CO_2 and NO_x from coal combustion furnaces. In this paper, an unsteady-state model of pulverized coal cloud consider the radiation and convection was used, by numerical simulation, a typical bituminous coal ignition characteristics was studied in air and O_2/CO_2 atmosphere and also carried out experiment study, experiment results are in good agreement with the calculated results. Results show that when the atmosphere changed from air to O_2/CO_2, ignition delay time and ignition temperature both increased, the range of temperature increase is about 10-20K. With the increase of coal concentration the ignition delay time and ignition temperature reduced under O_2/CO_2 atmosphere, the ignition delay time is reduced when the ambient temperature is increased, and the ambient temperature has a greater impact on ignition delay time under O_2/CO_2 atmosphere, leading a longer ignition delay time.