Study on the effect of Mg2+ and Na+ on the fusibility of coal ash with high ash fusion point
-
摘要: 以山西阳泉固庄高熔点煤灰为研究对象,通过向煤灰中添加不同量的MgO与Na2CO3,研究了Mg2+与Na+在高温下对煤灰熔融性的影响。研究结果表明,煤灰熔融温度随氧化镁的添加(5%~25%)单调下降;而随氧化钠添加(5%~25%)出现先降后升现象,在氧化钠添加量为15% 时,灰熔点达到最低。XRD分析表明,阳泉固庄煤灰熔融温度高(大于1 750℃)的原因是高温条件下耐熔矿物莫来石、方英石的存在。添加外加剂后,高温时外加剂与硅酸盐矿物反应,生成了更多的低共熔矿物霞石、堇青石等。同时,Mg2+和Na+的加入会使得非桥氧数量增多,高温煤灰低聚物增多,降低了煤灰的熔融温度。通过三元相图以及SEM分析,高温条件下煤灰中部分元素的富集以及团聚现象是导致Mg2+和Na+对煤灰熔融温度影响不同的原因。Abstract: Adjustment of coal ash fusibility of high fusion point coal has been attracted by attention of many researchers in coal gasification and combustion. The effect of Mg2+ and Na+ on the fusibility behavior of the high fusion temperature coal ash from Yangquan Guzhuang was studied in this paper, using the method of adding different amount of MgO and Na2CO3 (5%~25%) to the coal ash. The result shown that the ash fusion temperature monotonically decreases with increasing addition amount of MgO, while the ash fusion temperatures exhibit low valley and reach the minimum when the addition amount of Na2CO3 is 15%. Investigated by XRD, mullite and cristobalite are detected in the Yangquan Guzhuang coal ash, which results in the ash fusion temperature of the coal ash higher than 1 750℃. Additions reacting with silicate minerals can form more low-melting eutectic minerals, such as cordierite and nepheline, etc. Meanwhile, the additions of Mg2+ and Na+ cause non-bridged oxygen and oligomers increasing, then the ash fusion temperature reduce. Ternary phase diagram and SEM micrograph confirm that the local clustering of partial elements and reunited phenomenon of coal ash under high temperature condition result in the different effect of Mg2+ and Na+ on the coal ash fusibility behavior.
-
Key words:
- ash fusion point /
- coal ash /
- fusibility
-
贺根良, 门长贵. 气流床气化炉操作温度的探讨[J]. 煤化工, 2007, 35(4): 8-11. (HE Gen-liang, MEN Chang-gui. Discussion on the operational temperature for entrained flow gasifiers[J]. Coal Chemical Industry, 2007, 35(4): 8-11.) 乌晓江, 张忠孝, 朴桂林, 小林信介, 森滋勝, 板谷羲紀. 高灰熔点煤高温下煤焦CO2/水蒸气气化反应特性的实验研究[J]. 中国电机工程学报, 2007, 27(32): 24-28. (WU Xiao-jiang, ZHANG Zhong-xiao, PIAO Gui-lin, KOBAYASHI N, MORI S, ITATYA Y. Experimental study on gasification reaction characteristics of Chinese high ash fusion temperature coal with CO2 and steam at elevated temperature[J]. Journal of Proceedings of the CSEE, 2007, 27(32): 24-28.) 王艳柳, 张晓慧. 煤灰熔融性对气化用煤的影响[J]. 煤质技术, 2009, (4): 55-58. (WANG Yan-liu, ZHANG Xiao-hui. Effect of ash fusibility on gasifying coal[J]. Journal of Coal Quality and Technology, 2009, (4): 55-58.) 李宝霞, 张济宇. 煤灰渣熔融特性的研究进展[J]. 现代化工, 2005, 25(5): 22-28. (LI Bao-xia, ZHANG Ji-yu. Research progress of coal ash fusibility[J]. Journal of Modern Chemical Industry, 2005, 25(5): 22-28.) HURST H J. Phase diagram approach to the fluxing effect of additions of CaCO3 on Australian coal ashes[J]. Energy Fuels, 1996, 10(6): 1215-1219. 范立明, 陈杰瑢, 田晓莉, 黄传卿, 杜晓玮. 石灰石添加量对黄陵煤灰熔融特性的影响[J]. 煤化工, 2007, 35(2): 31-63. (FAN Li-ming, CHEN Jie-rong, TIAN Xiao-li, HUANG Chuan-qing, DU Xiao-wei. Study of the optimum amount of limestone addition in preparation of coal water slurry[J]. Coal Chemical Industry, 2007, 35(2): 31-63.) 许志琴, 于戈文, 邓蜀平, 董众兵, 李永旺. 助熔剂对高灰熔点煤影响的实验研究[J]. 煤炭转化, 2005, 28(3): 22-25. (XU Zhi-qin, YU Ge-wen, DENG Shu-ping., DONG Zhong-bing, LI Yong-wang. Experimental studies on the effect of fusion agents on high ash-melting coals[J]. Coal Conversion, 2005, 28(3): 22-25.) 李继炳, 沈本贤, 赵基钢, 王基铭. 镁基助熔剂对刘桥二矿混煤灰熔融特性的影响[J]. 煤炭转化, 2009, 32(2): 37-40. (LI Ji-bing, SHEN Ben-xian, ZHAO Ji-gang, WANG Ji-ming. Effect of magnesium-based flux on the melting characteristics of coal ash from coal blends using the Liuqiao No.2 coal mine[J]. Coal Conversion, 2009, 32(2): 37-40.) QIU J-R, LI F, ZHENG Y, ZHENG C-G, ZHOU H-C. The influences of mineral behavior on blend coal ash fusion characteristics [J]. Fuel, 1999, 78(8): 963-969. LI Ji-bing, SHEN Ben-xian, LI Han-xun, ZHAO Ji-gang, WANG Ji-ming. Effect of ferrum-based flux on the melting characteristics of coal ash from coal blends using the Liuqiao No.2 coal mine in Wanbei[J]. J Fuel Chem Technol, 2009, 37(3): 262-265. 乌晓江, 张忠孝, 朴桂林, 森 滋勝, 板谷 羲纪, 陈龙. 配煤对降低高灰熔融性煤的三元相图分析[J]. 洁净煤技术, 2007, 13(3): 64-67. (WU Xiao-jiang, ZHANG Zhong-xiao, PIAO Gui-lin, MORI S, ITATYA Y, CHEN Long. Analysis of coal ash fusion characteristics of high fusibnity coal blending with low's with ternary phase diagram[J]. Clean Coal Technology, 2007, 13(3): 64-67.) WU X, ZHANG Z, CHEN Y, ZHOU T, FAN J, PIAO G, KOBAYASHI N, MORI S, ITAYA Y. Main mineral melting behavior and mineral reaction mechanism at molecular level of blended coal ash under gasification condition[J]. Fuel Process Technol, 2010, 91(11): 1591-1600. VASSILEV S V, KITANO K, TAKEDA S, TSURUE T. Influence of mineral and chemical composition of coal ashes on their fusibility[J]. Fuel Process Technol, 1995, 45(1): 27-51. 高峰, 单晓伟. 煤灰在不同耐火砖表面的润湿性与侵蚀性研究[J]. 燃料化学学报, 2012, 40(7): 769-775. (GAO Feng, SHAN Xiao-wei. Wettability and erodibility of coal ash on the surface of different refractories[J]. Journal of Fuel Chemistry and Technology, 2012, 40(7): 769-775.) Van DYK J C, BAXTER L L, van HEERDEN J H P,COETZER R L J. Chemical fractionation tests on South African coal sources to obtain species-specific information on ash fusion temperatures (AFT)[J]. Fuel, 2005, 84(14-15): 1768-1777. 王勤辉, 景妮洁, 骆仲泱, 李小敏, 揭涛. 灰成分影响煤灰烧结温度的实验研究[J]. 煤炭学报, 2010, 35(6): 1015-1020. (WANG Qin-hui, JING Ni-jie, LUO Zhong-yang, LI Xiao-min, JIE Tao. Experiments on the effect of chemical components of coal ash on the sintering temperature[J]. Journal of China Coal Society, 2010, 35(6): 1015-1020.) 廖敏, 郭庆华, 梁钦锋, 袁海平, 倪建军, 于广锁. 气化条件下煤灰高温物相变化及其对黏度的影响[J]. 中国电机工程学报, 2010, 30(17): 45-50. (LIAO Min, GUO Qing-hua, LIANG Qin-feng, YUAN Hai-ping, NI Jian-jun, YU Guang-suo. Phase transformation of coal ash at high temperature under gasification conditions and its influence on viscosity[J]. Journal of Proceedings of the CSEE, 2010, 30(17): 45-50.) LI W, LI M, LI W-F, LIU H. Study on the ash fusion temperatures of coal and sewage sludge mixtures[J]. Fuel, 2010, 89(7): 1566-1572. 谷小虎, 曹敏, 王兰甫, 田亚鹏. 煤灰对气化反应性的影响[J]. 煤化工, 2009, 37(2): 19-21. (GU Xiao-hu, CAO Min, WANG Lan-pu, TIAN Ya-peng. Effect of ash on gasification reactivity[J]. Coal Chemical Industry, 2009, 37(2): 19-21.) 唐黎华, 王福明, 朱学栋, 吴勇强, 朱子彬. 煤焦中矿物质行为与灰熔融温度的关系[J]. 华东理工大学学报, 2003, 29(3): 243-247. (TANG Li-hua, WANG Fu-ming, ZHU Xue-dong, WU Yong-qiang, ZHU Zi-bin. Relationship between mineral behavior in coke and ash melting temperature[J]. Journal of East China University of Science and Technology, 2003, 29(3): 243-247.)
点击查看大图
计量
- 文章访问数: 2164
- HTML全文浏览量: 19
- PDF下载量: 836
- 被引次数: 0