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This paper evaluates the effect of the air temperature on the combustion characteristics and NO x formation in a 0.5 MW laboratory furnace fired by a pulverized coal swirl burner with deep air staging. The temperature and compositions of flue gas and fly ash in the primary zone and the second burnout zone were sampled and measured. The results show that air temperature in the deep air staging has a significant effect on the flame stability, emissions of NO x , and unburnt carbon content in fly ash. When the air temperature is increased from 200 to 400 °C, in the primary zone (the stoichiometric ratio is 0.85), the ignition of flame is advanced, the flame stability improved significantly, the overall temperature level and combustion rate increased significantly, the CO concentration increased, the NO x concentration decreased significantly, and the carbon, hydrogen, and nitrogen release rates and the char burnout increased significantly. After the overfire air injection, in the second burnout zone, as the air temperature is increased, the NO x concentration decreased but the formation of NO x in the second burnout zone increased significantly, as well as the contribution of N species conversion to NO x . As the combustion reaction is completed, the final char burnout increased from 96.4 to 99.8%.

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In this paper, Al-7%Si-0.6%Mg-X%Ce (X=0, 0.1 and 0.2) casting alloys were prepared by vacuum induction furnace. Using optical microscopy (OM), X-ray diffractometer (XRD), scanning electron microscopy (SEM), energy spectrometry (EDS), differential scanning calorimetry (DSC) and transmission electron microscopy (TEM), the microstructures of the experimental alloys were studied, and the mechanism of refinement and modification of the alloy were discussed. Results show that AlCeSi2 was formed after adding cerium element in the Al alloy, besides those compounds of α-Al, silicon, eutectic of α-Al + Si and iron-rich phase. Furthermore, with the increase of cerium addition, α- Al dendrite arms decrease, the AlCeSi2 was formed, and the growth of iron-rich phase was hindered, respectively. Also, the areas of eutectic of α-Al + Si were decreased, due to the supercooling increasing of the alloys. In addition, the α-Al grains were refined, because existing of heterogeneous nucleation core supplied by AlCeSi2, and component supercooling caused by cerium adding. Moreover, the formation of AlCeSi2 consumed to some silicon elements, which leaded to size and amount reduction of eutectic silicon. The formation of high-density stacking fault can induce silicon modified, and the formed high-density stacking fault was produced by cerium as impurity element into silicon.