弱还原气氛下水稻秸秆对晋城无烟煤的助熔机理

以高灰熔点的晋城无烟煤和水稻秸秆为研究对象,通过CaO-Al_2O_3-SiO_2三元相图、X射线衍射分析(XRD)和扫描电镜耦合X射线能谱分析(SEM-EDX)研究了弱还原气氛下水稻秸秆对晋城无烟煤的助熔机理。随着水稻秸秆添加比例的增加,灰熔融特征温度呈下降趋势,灰中碱性氧化物CaO、Na_2O和K_2O含量增多,结渣指数Rb/a值在0.20-0.69;当水稻秸秆添加量为20%(质量分数)时,流动温度(FT)降低至1 369℃,可满足气化炉液态排渣的要求;水稻秸秆的添加降低了灰中液相出现的温度,增加了液相物质出现的比例和几率,使灰更易发生熔融;混合灰中所形成的钠长石等低熔点矿物质以及钙长石、石英和莫来石所形成的低温共熔物导致灰熔点降低。

Fluxing mechanism of rice straw for Jincheng anthracite under weak reducing atmosphere

The fluxing mechanism of rice straw for Jincheng anthracite with high ash fusion temperatures was investigated under weak reducing atmosphere by CaO-Al₂O₃-SiO₂ ternary phase diagram, X-ray diffraction (XRD) and scanning electron microscopy coupled with energy dispersive X-ray spectrometry (SEM-EDX). The fusion temperatures of blended ash decrease, and the content of basic oxide CaO,Na₂O and K₂O increases with increment of rice straw addition. The slagging index R_b/a is between 0.20 and 0.69. The fluid temperature (FT) declines to 1 369℃ by adding 20% rice straw, which could satisfy requirement of liquid slag discharge for gasifier. The addition of rice straw reduces the initial temperature and increases the occurrences proportion and probability of liquid phase in the ash. The formation of crystal albite with low melting point and eutectics formed from anorthite,quartz and mullite lead the decrease of ash fusion temperatures.