Numerical simulation of the swirling pulverized coal combustor used for asphalt mixing plants

Coal-fired heating will greatly save the operating costs in an asphalt mixing plant operating costs. In this pa- per,we designed swirl combustor burning 4 t / h pulverized coals for the heating system of asphalt mixing plant and nu- merically studied the combustion characteristic of the swirl chamber was numerically studied. The results revealed that pulverized coal particles were rapidly heated up and stably burnt in the combustor. The distributions of the velocity and temperature fields were rather symmetric. The velocity filed of swirling combustor was determined by the swirl burner and the secondary airs which tangentially shooting into the combustor. When the offset angle between the secondary air and the radial line was greater than 60° and the primary air rate was 0. 15-0. 20,the flow field in the combustor soun- ded reasonable,with a combustion efficiency of 97% -99% ,the NOx concentration at the exit around 650 mg / Nm3 and excellent load adjustability. Simulation results demonstrated that the swirling pulverized coal combustion is feasible for the asphalt mixing plant and provided some guidance for the combustor design.