Experiments And Numerical Simulation On Oxygen-enriched Combustion And Direct Ignition Of Pulverized Coal

Energy and environment are very important topics for human's development, energy saving and environment protection are the world's most important problems for sustainable development. Oxygen-enriched combustion and ignition of pulverized coal technology may be the effective method to save energy and protect environment. This work was involved in the oxygen-enriched combustion experiment and new style of oxygen-enriched burner's direct ignition numerical simulation research on the most key problem of oxygen-enriched combustion and ignition of PC.Direct oxygen-enriched ignition of PC is a special form of oxygen-enriched combustion, so the research of the paper was based on the oxygen-enriched combustion of PC. In this work, the oxygen-enriched combustion experiments associate with numerical simulation of horizontal furnace was carried out, including the combustion characteristics and burn-off law. The temperature, the combustion efficiency and the speed of combustion were enhanced in oxygen-enriched combustion. On the other hand, the emission of CO was decreased, the law of NO_x was first increased and then decreased, SO₂'s emission was also increased.The new style of oxygen-enriched burner's direct ignition technology was studied on the base of oxygen-enriched combustion experiment of horizontal furnace.There were two key problems of direct ignition technology, one was the structure the burner, the other was the condition parameters of ignition process. The flow field of burner was first studied in the paper. The most important feature of new style of oxygen-enriched burner's flow field was also performed by both experiment and numerical simulation, including the position of bluff body, the flux of primary air, the velocity of centre air, the velocity of boundary air and so on. According to the numerical simulation, the laws of oxygen field was also carried out in the partial oxygen-enriched condition from the feature of convection and diffuse; the proper structure of oxygen field and the process of oxygen mixed with primary air were extracted creativity.Direct oxygen-enriched ignition is an unstable process, whether the ignition can succeed depends on the stable combustion after ignition. In this work, in order to study the key problem of oxygen-enriched ignition of PC, the stable combustion was first studied by EBU model, including the concentration of PC, the method of oxygen-enriched and the velocity of primary. The influence of different position of bluff body on combustion was also performed. Because of the special structure of oxygen-enriched burner, the influence of center air on combustion in common operating condition after ignition was studied in this work. The method to avoid the phenomenon of firing-carrying was also suggested. According to the study of above, some useful suggestions on the practice of oxygen-enriched ignition can be received.