准东煤流化床气化飞灰的理化特性研究

采用灰熔点测定仪、X射线荧光光谱仪、扫描电镜和热重分析仪等方法,研究了准东煤流化床气化飞灰的灰熔融特性、物理结构和化学组成及气化反应活性。结果表明,准东煤与其流化床气化飞灰中Si O2、Fe2O3、Na2O和Ca O等矿物质含量存在显著的差异,但飞灰的灰熔点与原煤无明显差异。准东煤气化飞灰具有较宽的粒径范围,呈现双峰分布特征,且不同粒径区间飞灰的元素含量存在显著差异。提高气化温度,有利于提高飞灰的气化反应活性。准东煤流化床气化飞灰石墨化程度比煤焦要高,但其孔隙结构更为发达,含有丰富的中孔和中大孔,使得飞灰的气化反应活性高于煤焦。可通过提高气化温度、循环再气化的方法提高气化效率。

Physical and chemical properties of fly ash from fluidized bed gasification of Zhundong coal

The ash fusion characteristics, physical structure, chemical compositions and gasification reactivity of Zhundong coal (ZD) fly ash from fluidized bed gasification were explored by fusion point analyzer, X-ray fluorescence spectrometer (XRF), scanning electron microscopy (SEM), and thermo-gravimetric analyzer. The results show that the concentrations of minerals in ZD fly ash, such as SiO₂, Fe₂O₃, Na₂O, CaO, change greatly during gasification process, but the ash fusion temperature of ZD fly ash is similar to that of ZD. There is a wide particle-size distribution in ZD fly ash, which shows a significant bimodal distribution, and a large difference of elemental compositions for ZD fly ash of different particle size. The reactivity of ZD fly ash increases with the increase in gasification temperature. Compared with the ZD char from pyrolysis, the ZD fly ash has more advanced carbon crystalline structure, a larger surface area and is relatively rich in meso-pores and macro-pores, which results in a higher gasification reactivity.