Mineral transformation during Zhundong coal combustion by CCSEM

doi:10.11949/j.issn.0438-1157.20151438

Abstract

Abstract:

The mineralogy of Zhundong coal and its combustion-generated particles were characterized in detail by computer controlled scanning electron microscopy (CCSEM). The experiment was done on a lab-scale drop tube furnace. The results showed that there were calcite, kaolinite, pyrite, pyrrhotite, oxidized pyrrhotite and unclassified minerals in Zhundong coal. The mass fraction of quartz, iron oxide and dolimite increased sharply, while the mass fraction of calcite and unclassified minerals decreased. Also, the behaviors of Na, Fe and Ca as the important elements to the ash deposition, and their particle size distributions were investigated.

Key words: fuel, coal combustion, reaction, CCSEM, mineral transformation

摘要：

在沉降炉中进行了准东煤的燃烧实验,利用计算机控制扫描电镜技术(computer controlled scanning electron microscopy,CCSEM)研究了煤中矿物质的转化行为。研究表明煤中主要矿物为方解石、高岭石、含铁类物质以及未分类矿物,燃烧后灰中石英、铁的氧化物、白云石的含量急剧增加,未分类矿物和方解石的含量下降。同时对3种重要致渣元素Na、Fe、Ca在燃烧前后的矿物转化行为及颗粒粒径分布进行了详细研究。

关键词: 燃料, 煤燃烧, 反应, CCSEM, 矿物转化

CLC Number:

TK24

FAN Bin, YU Dunxi, ZENG Xianpeng, LÜ Weizhi, WU Jianqun, XU Minghou. Mineral transformation during Zhundong coal combustion by CCSEM[J]. CIESC Journal, 2016, 67(5): 2117-2123.

樊斌, 于敦喜, 曾宪鹏, 吕为智, 吴建群, 徐明厚. 准东煤燃烧中矿物质转化行为的CCSEM研究[J]. 化工学报, 2016, 67(5): 2117-2123.

References 27

[1]	张守玉, 陈川, 施大钟, 等. 高钠煤燃烧利用现状 [J]. 中国电机工程学报, 2013, 33 (5): 1-12. ZHANG S Y, CHEN C, SHI D Z, et al. Situation of combustion utilization of high sodium coal [J]. Proceedings of the CSEE, 2013, 33 (5): 1-12.
[2]	杨忠灿, 刘家利, 姚伟. 准东煤灰沾污指标研究 [J]. 洁净煤技术, 2013, 19 (2): 81-84. YANG Z C, LIU J L, YAO W. Fouling index of Zhundong coal ash [J]. Clean Coal Technology, 2013, 19 (2): 81-84.
[3]	BRYERS R W. Fireside slagging, fouling, and high-temperature corrosion of heat-transfer surface due to impurities in steam-raising fuels [J]. Progress in Energy and Combustion Science, 1996, 22 (1): 29-120. DOI: 10.1016//0360-1285(95) 00012-7.
[4]	NARUSE I, KAMIHASHIRA D, KHAIRIL, et al. Fundamental ash deposition characteristics in pulverized coal reaction under high temperature conditions [J]. Fuel, 2005, 84 (4): 405-410. DOI: 10.1016/j.fuel.2004.09.007.
[5]	翁青松, 王长安, 车得福, 等. 准东煤碱金属赋存形态及对燃烧特性的影响 [J]. 燃烧科学与技术, 2014, 20 (3): 216-221. WENG Q S, WANG C A, CHE D F, et al. Alkali metal occurrence mode and its influence on combustion characteristics in Zhundong coals [J]. Journal of Combustion Science and Technology, 2014, 20 (3): 216-221.
[6]	范建勇, 周永刚, 李培, 等. 准东煤灰熔融温度表征结渣特性的试验研究 [J]. 煤炭学报, 2013, 38 (S2): 478-482. FAN J Y, ZHOU Y G, LI P, et al. Research on Zhundong coal's ash melting temperature characterizing its slagging characteristics [J]. Journal of China Coal Society, 2013, 38 (S2): 478-482.
[7]	赵庆庆, 代纪邦, 金晶, 等. 添加剂对准东煤灰熔融特性的影响 [J]. 上海理工大学学报, 2014, 36 (6): 511-515. ZHAO Q Q,DAI J B,JIN J,et al. Effects of additives on Zhundong coal ash melting characteristics [J]. Journal of University of Shanghai for Science and Technology, 2014, 36 (6): 511-515.
[8]	王学斌, 魏博, 张利孟, 等. 温度和 SiO2 添加物对准东煤中碱金属的赋存形态及迁徙特性的影响 [J]. 热力发电, 2014, (8): 84-88. DOI:10.3969/j.issn. 1002-3364. 2014.08.084. WANG X B, WEI B, ZHANG L M, et al. Effect of temperature and silicon additives on occurrence and transformation characteristics of alkali metal in Zhundong coal [J]. Thermal Power Generation, 2014, (8): 84-88. DOI:10.3969/j.issn.1002-3364.2014.08.084.
[9]	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, 2015, 42 (1): 20-25. MA Y, HUANG Z Y, TANG H R, et al. Mineral conversion of Zhundong coal during ashing process and the effect of mineral additives on its ash fusion characteristics [J]. Journal of Fuel Chemistry and Technology, 2015, 42 (1): 20-25.
[10]	王礼鹏, 赵永椿, 张军营, 等. 准东煤沾污结渣特性研究 [J]. 工程热物理学报, 2015, 36 (6): 1381-1385. WANG L P, ZHAO Y C, ZHANG J Y, et al. Research on the slagging and fouling of Zhundong coal [J]. Journal of Engineering Thermophysics, 2015, 36 (6): 1381-1385.
[11]	WARD C R. Analysis and significance of mineral matter in coal seams [J]. International Journal of Coal Geology, 2002, 50 (1): 135-168. DOI:10.1016/S0166-5162(02)00117-9.
[12]	HUGGINS F E. Overview of analytical methods for inorganic constituents in coal [J]. International Journal of Coal Geology, 2002, 50 (1): 169-214. DOI:10. 1016/S0166-5162(02)00118-0.
[13]	GUPTA R P, WALL T F, KAJIGAYA I, et al. Computer-controlled scanning electron microscopy of minerals in coal—implications for ash deposition [J]. Progress in Energy and Combustion Science, 1998, 24 (6): 523-543. DOI:10.1016/S0360-1285(98) 00009-4.
[14]	ZYGARLICKE C J, STEADMAN E N. Advanced SEM techniques to characterize coal minerals [J]. Scanning Microscopy, 1990, 4 (3): 579-590.
[15]	YU D X, XU M H, ZHANG L, et al. Computer-controlled scanning electron microscopy (CCSEM) investigation on the heterogeneous nature of mineral matter in six typical Chinese coals [J]. Energy & Fuels, 2007, 21 (2): 468-476. DOI: 10.1021/ef060419w.
[16]	YU D X, XU M H, YAO H, et al. Use of elemental size distributions in identifying particle formation modes [J]. Proceedings of the Combustion Institute, 2007, 31 (2): 1921-1928. DOI:10.1016/j.proci. 2006. 07. 115.
[17]	TEN B H, EENKHOORN S, WEEDA M. The behaviour of coal mineral carbonates in a simulated coal flame [J]. Fuel Processing Technology, 1996, 47 (3): 233-243. DOI:10.1016/0378-3820(96)01012-0.
[18]	YAN L, GUPTA R, WALL T. Fragmentation behavior of pyrite and calcite during high-temperature processing and mathematical simulation [J]. Energy & Fuels, 2001, 15 (2): 389-394. DOI: 10.1021/ef000157c.
[19]	兰泽全, 曹欣玉, 饶甦, 等. 电子探针分析炉内沾污结渣动态过程 [J]. 化工学报, 2005, 56 (1): 24-29. LAN Z Q, CAO X Y, RAO S, et al. Fouling and slagging dynamic processes in boiler with electron probe microanalyzer [J]. Journal of Chemical Industry and Engineering (China), 2005, 56 (1): 24-29.
[20]	吴乐, 吴建群, 罗嘉, 等. 煤样不同密度组分中致渣矿物特性的 CCSEM 研究 [J]. 化工学报, 2014, 65 (8): 3221-3227. DOI: 10.3969/j.issn.0438-1157.2014.08.050. WU L, WU J Q, LUO J, et al. CCSEM investigation on slag-inducing minerals in density-segregated coal samples [J].CIESC Journal, 2014, 65 (8): 3221-3227. DOI:10.3969/j.issn.0438-1157.2014.08.050.
[21]	吴乐, 吴建群, 于敦喜, 等. O2/CO2 燃烧对神华煤 Ca 和 Fe 交互反应影响 [J]. 化工学报, 2015, 66 (2): 753-758. DOI: 10.11949/j.issn.0438-1157.20141162. WU L, WU J Q, YU D X, et al. The influence of O2/CO2 combustion on interaction of Ca and Fe in Shenhua coal [J]. CIESC Journal, 2015, 66 (2): 753-758. DOI: 10.11949/j.issn.0438-1157.20141162.
[22]	BRYANT G W, BROWNING G J, EMANUEL H, et al. The fusibility of blended coal ash [J]. Energy & Fuels, 2000, 14 (2): 316-325. DOI: 10.1021/ef990093+.
[23]	张军, 汉春利, 颜铮, 等. 煤中钠在燃料初期行为的研究 [J]. 燃料化学学报, 2001, 29 (1): 49-53. DOI: 10.3969/j.issn.0253-2409.2001.01.010. ZHANG J, HAN C L, YAN Z, et al. Experimental studies on the behaviour of sodium of coal in the initial stage of combustion [J]. Journal of Fuel Chemistry and Technology, 2001, 29 (1): 49-53. DOI:10.3969/j.issn.0253-2409.2001.01.010.
[24]	MARSKELL W G, MILLER J M. Some aspects of deposit formation in pilot-scale pulverized-fuel-fired installations [J]. J. Inst. Fuel, 1956, 29 (188): 380-387.
[25]	LEE S H, TEATS F G, SWIFT W M, et al. Alkali-vapor emission from PFBC of illinois coals [J]. Combustion Science and Technology, 1992, 86 (1-6): 327-336.
[26]	张军, 汉春利, 刘坤磊, 等. 煤中碱金属及其在燃烧中的行为 [J]. 热能动力工程, 1999, 14 (2): 83-85. DOI: 10.3969/j.issn.1001-2060.1999.02.002. ZHANG J, HAN C L, LIU K L, et al. Various forms of alkali metal in coal and its behavior during coal combustion [J]. Journal of Engineering for Thermal Energy & Power, 1999, 14 (2): 83-85. DOI: 10. 3969/j.issn.1001-2060.1999.02.002.
[27]	RASSK E. The behavior of potassium silicates in pulverized coal firing [J]. Progress in Energy and Combustion Science, 1982, 1 (8): 261-276.