氧化钙对贵州六盘水高硅铝煤灰熔融性的影响及机理
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摘要
针对贵州六盘水老鹰山矿区的高硅铝难熔煤灰,在SiO_2-Al_2O_3-CaO三元相图指导下,通过添加CaO对煤灰的熔融性进行调节。利用水冷法研究了CaO对煤灰熔融性的影响机理。采用Factsage软件进行了CaO对煤灰熔融性影响机理的热力学计算。结果表明:随着CaO的增加,煤灰的熔融温度和完全熔化温度均呈现先下降后上升的趋势,当CaO为33.56%(质量分数)时,煤灰的流动温度(FT)为1 236℃;煤灰的高温物相变化和热力学计算均表明,莫来石和石英等高熔点物相的存在是导致高硅铝煤灰难熔的原因,而添加CaO能够破坏煤灰中的难熔矿物并形成钙长石、钙铝黄长石和硅灰石等低熔点化合物,这些矿物容易形成低温共熔混合物而降低煤灰的熔融温度,但过多的CaO会促使煤灰形成多余的钙铝黄长石,使得煤灰越过低共熔区域,导致煤灰的熔融温度升高。
Aiming at improving the fusibility of high silica-alumina refractory coal ash in the Laoyingshan mining area of Liupanshui,Guizhou,CaO was added according to the ternary phase diagram of SiO_2-Al_2 O_3-CaO.Water cooling method was adopted to investigate the mechanism of the effects of CaO on the fusibility of coal ash,the calculation of which was carried out using the Factsage software.The results show that with the increase of mass fraction of CaO,both of the liquidus temperature and fusion temperature of coal ash decrease and then increase.When mass fraction of CaO is 33.56%,the FT(flow temperature)of coal ash is 1 236 ℃;The phase change and thermodynamic calculations indicate that the high silica-aluminum ash being refractory can be attributed to the presence of high melting point phases,such as mullite and quartz.The added CaO can destroy the refractory minerals in the coal ash and form compounds with low liquidus temperature,such as anorthite,gehlenite,wollastonite,and then these compounds tend to form a low-temperature eutectic mixture to reduce the fusion temperature of coal ash.However,excessive CaO will cause the coal ash to form excess gehlenite,which can make the coal ash go through the low melting temperature zone,increasing the fusion temperature of the coal ash.
Aiming at improving the fusibility of high silica-alumina refractory coal ash in the Laoyingshan mining area of Liupanshui,Guizhou,CaO was added according to the ternary phase diagram of SiO_2-Al_2 O_3-CaO.Water cooling method was adopted to investigate the mechanism of the effects of CaO on the fusibility of coal ash,the calculation of which was carried out using the Factsage software.The results show that with the increase of mass fraction of CaO,both of the liquidus temperature and fusion temperature of coal ash decrease and then increase.When mass fraction of CaO is 33.56%,the FT(flow temperature)of coal ash is 1 236 ℃;The phase change and thermodynamic calculations indicate that the high silica-aluminum ash being refractory can be attributed to the presence of high melting point phases,such as mullite and quartz.The added CaO can destroy the refractory minerals in the coal ash and form compounds with low liquidus temperature,such as anorthite,gehlenite,wollastonite,and then these compounds tend to form a low-temperature eutectic mixture to reduce the fusion temperature of coal ash.However,excessive CaO will cause the coal ash to form excess gehlenite,which can make the coal ash go through the low melting temperature zone,increasing the fusion temperature of the coal ash.
引文
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[18]代廷魁.改善高铝煤灰熔融特性及助熔机理研究[D].淮南:安徽理工大学,2016.DAI Tingkui.Study on Improving Ash Fusibility and Fluxing Mechanism of High Alumina Coal[D].Huainan:Anhui University of Science and Technology,2016.
[19]芦涛,张雷,张晔,等.煤灰中矿物质组成对煤灰熔融温度的影响[J].燃料化学学报,2010,38(1):23-28.LU Tao,ZHANG Lei,ZHANG Ye,et al.Effect of Mineral Composition on Coal Ash Fusion Temperature[J].Journal of Fuel Chemistry and Techology,2010,38(1):23-28.
[20]马岩,黄镇宇,唐慧儒,等.准东煤灰化过程中的矿物演变及矿物添加剂对其灰熔融特性的影响[J].燃料化学学报,2014,42(1):20-25.MA Yan,HUANG Zhenyu,TANG Huiru,et al.Mineral Conversion of Zhundong Coal During Ashing Process and the Effect of Mineral Additives on Its Ash Fusion Characteristic[J].Journal of Fuel Chemistry and Technology,2014,42(1):20-25.
[21]李寒旭.还原性气氛下淮南煤灰行为特征的研究[D].淮南:安徽理工大学,2009.LI Hanxu.Study on Behavior Characteristics of Huainan Coal Ash in Reductive Atmosphere[D].Huainan:Anhui University of Technology,2009.
[22]WU Xiaojiang,ZHANG Zhongxiao,CHEN Yushuang,et al.Main Mineral Melting Behavior and Mineral Reaction Mechanism at Molecular Level of Blended Coal Ash Under Gasification Condition[J].Fuel Processing Technology,2010,91(11):1591-1600.
[23]许洁,刘霞,张庆,等.高钙山鑫煤灰熔融及黏温特性分析[J].中国电机工程学报,2013,33(20):46-51.XU Jie,LIU Xia,ZHANG Qing,et al.Research of Ash Fusibility and Viscous-temperature Characteristics of High-calcium Shanxin Coal Ash[J].Proceeding of the CSEE,2013,33(20):46-51.
[24]张文玲.烧结法赤泥对晋城无烟煤灰熔融特性的影响[J].矿产综合利用,2018(6):111-115.ZHANG Wenling.Effect of the Red Muds on Ash Fusion Characteristics of Jincheng Coal[J].Multipurpose Utilization of Mineral Resources,2018(6):111-115.
[25]MAO Huahai,HILLERT M,SELLEBY M,et al.Thermodynamic Assessment of the CaO-Al2O3-SiO2System[J].Journal of the American Ceramic Society,2006,89(1):298-308.
[2]陈权,仝胜录,王晓磊,等.水煤浆气化过程渣-水平衡系统的模拟[J].现代化工,2015,35(3):152-154.CHEN Quan,TONG Shenglu,WANG Xiaolei,et al.Simulation of Slag-water System in Coal-water Slurry Gasification Process[J].Modern Chemical Industry,2015,35(3):152-154.
[3]黄戒介,房倚天,王洋.现代煤气化技术的开发与进展[J].燃料化学学报,2002,35(5):385-391.HUANG Jiejie,FANG Yitian,WANG Yang.Development and Progress of Modern Coal Gasification Technology[J].Journal of Fuel Chemistry and Technology,2002,35(5):385-391.
[4]PATTERSON J H,HURST H J.Ash and Slag Qualities of Australian Bituminous Coals for Use in Slagging Gasifiers[J].Fuel,2000,79(13):1671-1678.
[5]台培杰,袁海平,梁钦锋,等.煤灰和熔渣的熔融特性和黏温特性比较[J].华东理工大学学报(自然科学报),2010,36(6):765-770.TAI Peijie,YUAN Haiping,LIANG Qinfeng,et al.Comparative Study on Fusibility and Viscosity-temperature Characteristics of Coal Ash and Slag[J].Journal of East China University of Science and Technology(Natural Science Edition),2010,36(6):755-770.
[6]BRYANT G W,LUCAS J A,GUPTA S K,et al.Use of Thermomechanical Analysis to Quantify the Flux Additions Necessary for Slag Flow in Slagging Gasifiers Fired with Coal[J].Energy and Fuels,1998,12(12):257-261.
[7]ELLIOTT L,WANG Shenmao,WALL Terry,et al.Dissolution of Lime Into Synthetic Coal Ash Slags[J].Fuel Processing Technology,1998,56(1/2):45-53.
[8]BAI Jin,LI Wen,LI Chunzhu,et al.Influence of Coal Blending on Mineral Transformation at High Temperatures[J].Mining Science and Technology(China),2009,19(3):300-305.
[9]BAI Jin,LI Wen,LI Chunzhu,et al.Influences of Minerals Transformation on the Reactivity of High Temperature Char Gasification[J].Fuel Processing Technology,2010,91(4):404-409.
[10]马志斌,白宗庆,白进,等.高温弱还原气氛下高硅铝比煤灰变化行为的研究[J].燃料化学学报,2012,40(3):279-285.MA Zhibin,BAI Zongqing,BAI Jin,et al.Evolution of Coal Ash with High Si/Al Ratio Under Reducing Atmosphere at High Temperature[J].Journal of Fuel Chemistry and Technology,2012,40(3):279-285.
[11]龙永华,张德祥,高晋生,等.提高煤灰熔融温度及其机理的研究[J].工业锅炉,2004(4):12-16.LONG Yonghua,ZHANG Dexiang,GAO Jinsheng,et al.Study of Increasing Coal Ash and Its Mechanism[J].Industrial Boiler,2004(4):12-16.
[12]王东旭,祁超,王洋,等.CaO含量对高钠煤灰熔融特性的影响[J].燃料化学学报,2017,45(9):1025-1034.WANG Dongxu,QI Chao,WANG Yang,et al.Effect of CaO Content on the Melting Properties of High Sodium Coal Ash[J].Journal of Fuel Chemistry and Technology,2017,45(9):1025-1034.
[13]刘硕,周安宁,杨伏生,等.氧化物添加剂对羊场湾煤灰熔融特性的影响[J].煤炭学报,2015,40(12):2954-2960.LIU Shuo,ZHOU Anning,YANG Fusheng,et al.Effect of Oxide Additives on Yangchangwan Coal Ash Fusion Characteristics[J].Journal of China Coal Society,2015,40(12):2954-2960.
[14]杨燕梅,张海,张扬,等.Si/Al/Na/Ca对准东煤灰熔融特性的影响[J].工程热物理学报,2018,39(8):1858-1863.YANG Yanmei,ZHANG Hai,ZHANG Yang,et al.Effect of Si/Al/Na/Ca on Ash Fusion Characteristics of Zhundong Coal[J].Journal of Engineering Thermophysics,2018,39(8):1858-1863.
[15]BALE C W,CHARTRAND P,DEGTEROV S A,et al.FactSage Thermochemical Software and Databases[J].Calphad,2002,26(2):189-228.
[16]JAK E,DEGTEROV S,HAYES P C,et al.Thermodynamic Modelling of the System Al2O3-SiO2-CaO-FeO-Fe2O3to Predict the Flux Requirements for Coal Ash Slags[J].Fuel,1998,77(1/2):77-84.
[17]徐荣声,王永刚,林雄超,等.配煤和助熔剂降低煤灰熔融温度的矿物学特性研究[J].燃料化学学报,2015,43(11):1303-1310.XU Rongsheng,WANG Yonggang,LIN Xiongchao,et al.Mineralogical Properties of Lowering Coal Ash Melting Temperature Using Blending Coal and Fluxing Agent[J].Journal of Fuel Chemistry and Technology,2015,43(11):1303-1310.
[18]代廷魁.改善高铝煤灰熔融特性及助熔机理研究[D].淮南:安徽理工大学,2016.DAI Tingkui.Study on Improving Ash Fusibility and Fluxing Mechanism of High Alumina Coal[D].Huainan:Anhui University of Science and Technology,2016.
[19]芦涛,张雷,张晔,等.煤灰中矿物质组成对煤灰熔融温度的影响[J].燃料化学学报,2010,38(1):23-28.LU Tao,ZHANG Lei,ZHANG Ye,et al.Effect of Mineral Composition on Coal Ash Fusion Temperature[J].Journal of Fuel Chemistry and Techology,2010,38(1):23-28.
[20]马岩,黄镇宇,唐慧儒,等.准东煤灰化过程中的矿物演变及矿物添加剂对其灰熔融特性的影响[J].燃料化学学报,2014,42(1):20-25.MA Yan,HUANG Zhenyu,TANG Huiru,et al.Mineral Conversion of Zhundong Coal During Ashing Process and the Effect of Mineral Additives on Its Ash Fusion Characteristic[J].Journal of Fuel Chemistry and Technology,2014,42(1):20-25.
[21]李寒旭.还原性气氛下淮南煤灰行为特征的研究[D].淮南:安徽理工大学,2009.LI Hanxu.Study on Behavior Characteristics of Huainan Coal Ash in Reductive Atmosphere[D].Huainan:Anhui University of Technology,2009.
[22]WU Xiaojiang,ZHANG Zhongxiao,CHEN Yushuang,et al.Main Mineral Melting Behavior and Mineral Reaction Mechanism at Molecular Level of Blended Coal Ash Under Gasification Condition[J].Fuel Processing Technology,2010,91(11):1591-1600.
[23]许洁,刘霞,张庆,等.高钙山鑫煤灰熔融及黏温特性分析[J].中国电机工程学报,2013,33(20):46-51.XU Jie,LIU Xia,ZHANG Qing,et al.Research of Ash Fusibility and Viscous-temperature Characteristics of High-calcium Shanxin Coal Ash[J].Proceeding of the CSEE,2013,33(20):46-51.
[24]张文玲.烧结法赤泥对晋城无烟煤灰熔融特性的影响[J].矿产综合利用,2018(6):111-115.ZHANG Wenling.Effect of the Red Muds on Ash Fusion Characteristics of Jincheng Coal[J].Multipurpose Utilization of Mineral Resources,2018(6):111-115.
[25]MAO Huahai,HILLERT M,SELLEBY M,et al.Thermodynamic Assessment of the CaO-Al2O3-SiO2System[J].Journal of the American Ceramic Society,2006,89(1):298-308.