摘要
为研究残炭对高镁煤灰熔融特性的影响,选取典型宁东气化用煤——梅花井煤为原料进行了不同残炭质量分数煤灰的灰熔融温度(t_(AF))测试。利用FactSage7.3热力学软件对煤灰熔融过程进行模拟计算,探究了不同残炭质量分数煤灰在一定温度区间内的矿物转变。利用X射线衍射(XRD)和扫描电子显微镜结合能量色散光谱仪(SEM-EDS)分别对煤灰的矿物质组成及微观形貌进行了表征。结果表明:在煤灰熔融过程中,钙长石和辉石类矿物质在1275℃开始熔融为液相,其含量明显降低,煤灰的熔融是熔融-溶解机制;煤灰在熔融过程形成大量的低温共熔物(橄榄石、尖晶石和辉石)主导了煤灰的熔融温度,从而使得煤灰的熔融温度较低;随着残炭质量分数增加,低熔点矿物尖晶石含量急剧增加,煤灰的熔融温度呈降低趋势,这是由于氧化镁的离子势较低(3.0);在高温条件下MgO对煤灰中其他组分的作用是氧给予体,而残炭的存在能够剥夺氧化镁中的氧,从而阻止多聚物聚集,引起煤灰熔融温度降低。
To investigate the effect of the carbon residue on the melting characteristics of the high-magnesium coal ash,Meihuajing coal,a typical gasification coal in Ningxia,was selected as the raw material to investigate the ash melting temperature(AFT)of the coal ash with diffe-rent contents of the residual carbon.FactSage7.3 thermodynamic software was adopted to simulate the melting process of the coal ash.Meanwhile,the mineral transformation of the coal ash in a certain temperature range was discussed.The mineral composition and microscopic morphology of the product were characterized by using the X-ray diffraction(XRD)and the scanning electron microscope combined with energy dispersive spectroscopy(SEM-EDS).The results show that during the melting process,the anorthite and pyroxene minerals start to melt into the liquid phase at 1275℃,and the content of which reduces significantly.The ash melting mechanism exhibites a“melt-dissolve”pattern.During the melting process,a large amount of the low-temperature eutectic olivine,spinel and pyroxene form,which play a dominant role in the melting temperature and lead to a low ash melting temperature.In addition,with the increasing residual carbon,the ash melting temperature decreases,because the content of the low melting point mineral(spinel)increases sharply.The reason is that the magnesium oxide,as an alkaline oxide,has a low ion potential of 3.0.At high temperatures,MgO provides oxygen for other ash components,while the residual carbon deprives the oxygen in the magnesium oxide,which inhibits the aggregation of the polymers and leads to the decrease in the melting temperature.
作者
刘斌
张林民
宋旭东
白永辉
苏暐光
许洁
于广锁
LIU Bin;ZHANG Linmin;SONG Xudong;BAI Yonghui;SU Weiguang;XU Jie;YU Guangsuo(State Key Laboratory of High-efficiency Coal and Green Chemical Engineering,College of Chemistry and Chemical Engineering,Ningxia University,750021 Yinchuan,China;Laboratory of Reaction and Separation Technology,Qingdao Agricultural University,266109 Qingdao,China;Institute of Clean Coal Technology,East China University of Science and Technology,200237 Shanghai,China)
出处
《煤炭转化》
CAS
CSCD
北大核心
2022年第1期73-81,共9页
Coal Conversion
关键词
灰熔融特性
高镁煤
残炭
热力学模拟
矿物演变
ash fusibility
high magnesium coal
residue carbon
thermodynamic simulation
mineral evolution
