糠醛渣对气化煤灰熔融特性影响的研究

Study on effect of furfural residue addition on fusion characteristics of gasification coal ash

本研究选择一种典型糠醛渣和两种硅铝比(Si/Al)不同的气化煤,考察配入糠醛渣对两种气化煤灰熔融温度的影响,利用X射线衍射仪(XRD)分析了不同温度下灰渣的矿物质变化规律,采用热力学计算软件FactSage计算了平衡状态下的物相变化。研究结果表明,随着糠醛渣配比的增加,两种气化煤灰的熔融温度均呈现先增加后降低的趋势,其中,高硅铝比的气化煤灰增加趋势更显著。配入糠醛渣后气化灰渣难熔相由钙长石(CaAl_(2)Si_(2)O_(8))变为白榴石(KAlSi_(2)O_(6)),白榴石(KAlSi_(2)O_(6))在1300℃仍以固相形式存在,导致灰熔融温度升高。硅铝比高的气化煤灰的SiO_(2)相对含量高,其与糠醛渣中的K2O反应生成更多高熔点的白榴石(KAlSi_(2)O_(6)),导致其熔融温度升高趋势更显著。随着糠醛渣配比的继续增加,共气化灰渣中K_(2)O含量增加,灰渣中形成低熔点的钾霞石(KAlSiO_(4)),降低了灰熔融温度。

The co-gasification of furfural residue with coal is a feasible way to realize its clean and efficient utilization,but there is a high content of alkaline components in the furfural residue ash.Therefore,the effect of furfural residue addition on the fusion temperature of gasification coal ash was investigated,in which a typical furfural residue and two gasification coals with different ratios of silicon to aluminum(Si/Al)were selected.X-ray diffraction instrument(XRD)was used to measure the mineral evolution of co-gasification ash at different temperatures.The phase change in equilibrium state was calculated by the software FactSage.The results show that with the increase in furfural residue addition ratio,the fusion temperatures of both gasification coal ashes first increase and then decrease,while the increase trend of fusion temperatures for the coal with a high Si/Al ratio is more significant.When the furfural residue is added,the resulting high melting point mineral of gasification slag is changed from anorthite(CaAl_(2)Si_(2)O_(8))to leucite(KAlSi_(2)O_(6))that is still present as a solid phase at 1300℃,resulting in an increase of AFTs.The coal ash with more amount of SiO_(2)can react with K_(2)O to produce more leucite(KAlSi_(2)O_(6))with a higher fusion point,thus causing the ash fusion temperatures to rise.However,as the ratio of furfural residue addition continues to increase,the ash fusion temperatures decrease,which is attributed to the formation of kaliophilite(KAlSiO_(4))with a low fusion point that is generated in the presence of higher content of K2O.