灰成分影响煤灰烧结温度的实验研究

利用压差法煤灰烧结温度测量装置，通过用化学纯试样替代煤中灰成分来改变煤灰不同组分的含量，研究了在典型燃烧反应气氛和气化反应气氛下SiO2、Fe2O3、Al2O3、CaO、Na2O、K2O等灰中化学成分对煤灰烧结温度的影响特性。实验结果表明，与燃烧气氛下SiO2成分一般提高烧结温度不同，气化气氛下添加的SiO2会与氧化物结合生成的硅氧化物和硅酸盐矿物群产生低共融现象，导致在一定含量范围内降低烧结温度；添加Fe2O3在气化气氛下能显著降低煤灰的烧结温度，在燃烧气氛下对烧结温度的影响不大；在燃烧气氛或气化气氛下，添加Al2O3和K2O对烧结温度影响较复杂，随着其加入会适当降低煤灰烧结温度，当其含量超过一定比例后又会提高煤灰烧结温度；无论在燃烧还是气化气氛下添加MgO都会降低煤灰烧结温度，但当其含量超过一定比例后对煤灰的烧结温度的影响不大；在煤灰中添加CaO和Na2O无论在燃烧气氛下还是气化气氛下都可以明显降低煤灰的烧结温度。

Experiments on the Effect of Chemical Components of Coal Ash on the Sintering Temperature

The sintering temperature of coal ash has an important effect on the design and operation of fluidized bed combustion or gasification systems. Experiments on the effects of chemical components of ash on the sintering behaviors have been completed on the pressure-drop measuring device by mixing the pure chemical samples into several coal ash samples under typical gasification and combustion atmosphere. The experimental results indicate that the sintering temperature increases with increasing the SiO2 content under the combustion atmosphere, but it will depend on the ash composition under the reducing atmosphere because the SiO2 may react with the other oxides to produce the low-melting eutectic minerals. The Fe2O3 may reduce the sintering temperature under typical fluidized bed gasification atmosphere. While the Al2O3 and K2O decrease the sintering temperature at first, but the contours indicate an increasing trend in the sintering temperature with increasing contents. While the MgO may reduce the ash sintering temperature in a small range at lower content, the CaO and Na2O may reduce the sintering temperature continuously with increasing their content under the gasification or combustion atmosphere.