高碱煤含钠矿物沉积层的高温熔融及多相反应过程分析

靳虎; 王泽安; 阳维; 宁坚; 谢逸豪; 刘豪

高碱煤含钠矿物沉积层的高温熔融及多相反应过程分析

华中科技大学煤燃烧国家重点实验室, 湖北武汉 430074

基金项目:

国家重点研发计划 2017YFC0703100

国家自然科学基金 51276074

详细信息

中图分类号: TK224.9
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- 被引次数: 0
出版历程
- 收稿日期: 2018-07-23
- 修回日期: 2018-10-28
- 网络出版日期: 2021-01-23
- 刊出日期: 2019-01-10

Melting behavior and heterogeneous reaction of Na-bearing deposits at high temperature during high-alkali coal combustion

State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074, China

Funds:

the National Key Research and Development Program of China 2017YFC0703100

the National Natural Science Foundation of China 51276074

More Information

Corresponding author: LIU Hao, E-mail:liuhao@hust.edu.cn

摘要

摘要: 采用纯矿物试剂模拟燃用高碱煤时炉内受热面典型的灰沉积层化学组成，利用热机械分析（TMA）、TG-DSC分析、高温煅烧实验结合XRD、SEM-EDS表征方法研究了不同Na₂SO₄含量灰沉积层的高温熔融过程及矿物间的多相反应机理。结果表明，掺混Na₂SO₄后沉积层熔化特征温度显著降低，Na₂SO₄的主要反应途径与掺混比例有关，当掺混比低于20%时，Na₂SO₄与SiO₂、CaO、Al₂O₃反应主要转变为CaSO₄和钠的硅铝酸盐；掺混比大于40%时则主要与CaSO₄生成低熔点的钠钙复合硫酸盐。富Na₂SO₄沉积层颗粒在800℃时开始黏结；900-950℃时，霞石、钠长石等钠的硅铝酸盐发生低温共熔，同时Na₂SO₄和CaSO₄生成的复合硫酸盐开始熔融，逐渐形成液相；1200-1250℃时，镁黄长石与含钙矿物发生强烈共熔，温度超过1300℃后矿物完全熔融成为自由液相。
- 硫酸钠 /
- 热机械分析 /
- 灰沉积 /
- 熔融 /
- 多相反应
Abstract: The pure chemicals were used to simulate the composition of typical ash deposits on heat exchanger surfaces during high-alkali coal combustion, and the thermal mechanical analysis (TMA), TG-DSC analysis and high-temperature calcination were performed to investigate the high temperature melting characteristics of the deposits with varying content of Na₂SO₄. Subsequently, XRD and SEM-EDS techniques were applied to investigate the reaction products and detailed mechanism. The results indicate that the melting characteristic temperature of deposits decreases significantly after blending with Na₂SO₄, and the transformation of Na₂SO₄ is closely related to the blending ratio. When the blending ratio is below 20% (mass ratio), most Na₂SO₄ is converted to CaSO₄ and sodium aluminosilicate, while Na₂SO₄ would react with CaSO₄ and generate sulfate double salts when the blending ratio is over 40%. Moreover, the particles of Na₂SO₄ enriched deposits begin to adhere at 800℃. When the temperature is elevated to 900-950℃, the low-temperature eutectics are easily formed in the presence of nepheline and albite, and the eutectics and Na-Ca sulfate double salts are gradually molten. The large amount of co-melting of akermanite and Ca-bearing minerals was observed at temperatures of 1200-1250℃, and the minerals are completely melted at temperatures over 1300℃.
- sodium sulfate /
- thermal mechanical analysis /
- ash deposits /
- melting /
- heterogeneous reaction

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图 1 不同Na₂SO₄含量样品的TMA收缩曲线(a)和收缩速率曲线(b)

Figure 1 TMA traces (a) and shrinkage rate curves (b) of samples with different Na₂SO₄ addition ratios

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图 3 Na₂O-SiO₂-Al₂O₃三元相图^[25]

Figure 3 Ternary phase diagram of Na₂O-SiO₂-Al₂O₃

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图 5 S1(a)和S3(b)在不同温度下煅烧的XRD谱图

Figure 5 XRD analysis of S1 (a) and S3 (b) at different temperatures

(a)-1: SiO₂; 2: CaO; 3:Fe₂O₃; 4: Al₂O₃; 5: MgO; 6: Ca₂Fe₂O₅; 7: CaSiO₃; (b)-1: Fe₂O₃; 2: SiO₂; 3: Al₂O₃; 4: CaO; 5: MgO; 6: CaSO₄; 7: MgFe₂O₄; 8: Ca₂Fe₂O₅; 9: CaSiO₃; a: Ca₂SiO₄; b: Ca₇Mg(SiO₄)₄; c: Ca₇MgSi₂O₇; d: Ca₃Mg(SiO₄)₂

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图 2 不同Na₂SO₄含量样品的特征温度

Figure 2 Characteristic temperatures of samples with different Na₂SO₄ addition ratios

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图 4 不同Na₂SO₄含量样品的TG(a)和DSC(b)曲线

Figure 4 TG (a) and DSC (b) curves of samples with different Na₂SO₄ addition ratios

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图 6 不同Na₂SO₄掺混比1100 ℃下煅烧的XRD谱图

Figure 6 XRD analysis of samples with different

Na₂SO₄ addition ratios at 1100 ℃ 1: SiO₂; 2: MgO; 3: Ca₂Fe₂O₅; 4: CaO; 5: Fe₂O₃; 6: MgFe₂O₄; 7: Ca₂SiO₄; 8: CaSiO₃; 9: CaSO₄; a: Ca₃Mg(SiO₄)₂; b: Ca₇Mg(SiO₄)₄; c: Ca₂Al₂SiO₇; d: Ca₂MgSi₂O₇; e: (Na_0.8Ca_0.1)₂SO₄; f: Na₂SO₄

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图 7 渣样的微观形貌和元素分析

Figure 7 Microstructure and elemental composition of slags

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表 1 样品的化学组成

Table 1 Chemical composition of samples

Sample	Content w/%
Sample	CaO	SiO₂	Al₂O₃	Fe₂O₃	MgO	Na₂SO₄
S1	40.00	30.00	10.00	12.00	8.00	0
S2	38.10	28.57	9.52	11.43	7.62	4.76
S3	36.36	27.27	9.09	10.91	7.27	9.09
S4	33.33	25.00	8.33	10.00	6.67	16.67
S5	28.57	21.43	7.14	8.57	5.71	28.57

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参考文献(30)

[1]	ZHOU J B, ZHUANG X G, ALASTUEY A, QUEROL X, LI J H. Geochemistry and mineralogy of coal in the recently explored Zhundong large coal field in the Junggar basin, Xinjiang province, China[J]. Int J Coal Geol, 2010, 82(1/2):51-67. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=71a689775945017c68624f19c8cbe0ab
[2]	张守玉, 陈川, 施大钟, 吕俊复, 王健, 郭熙, 董爱霞, 熊绍武.高钠煤燃烧利用现状[J].中国电机工程学报, 2013, 33(5):1-12. http://d.old.wanfangdata.com.cn/Periodical/zgdjgcxb201305001 ZHANG Shou-yu, CHEN Chuan, SHI Da-zhong, LV Jun-fu, WANG Jian, GUO Xi, DONG Ai-xia, XiONG Shao-wu. Situation of combustion utilization of high sodium coal[J]. Proc CSEE, 2013, 33(5):1-12. http://d.old.wanfangdata.com.cn/Periodical/zgdjgcxb201305001
[3]	WANG X B, XU Z X, WEI B, ZHANG L, TAN H Z, YANG T, MIKULCIC H, DUIC N. The ash deposition mechanism in boilers burning Zhundong coal with high contents of sodium and calcium:A study from ash evaporating to condensing[J]. Appl Therm Eng, 2015, 80:150-159. doi: 10.1016/j.applthermaleng.2015.01.051
[4]	SONG G L, SONG W J, QI X B, LU Q G. Transformation characteristics of sodium of zhundong coal combustion/gasification in circulating fluidized bed[J]. Energy Fuels, 2016, 30(4):3473-3478. doi: 10.1021/acs.energyfuels.6b00028
[5]	TOMECZEK J, PALUGNIOK H, OCHMAN J. Modelling of deposits formation on heating tubes in pulverized coal boilers[J]. Fuel, 2004, 83(2):213-221. doi: 10.1016/S0016-2361(03)00219-9
[6]	GLARBORG P, MARSHALL P. Mechanism and modeling of the formation of gaseous alkali sulfates[J]. Combust Flame, 2005, 141(1/2):22-39. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=c56fb184385f267f2494c4275287d07c
[7]	ZHOU H, ZHOU B, ZHANG H, LI L, CEN K. Investigation of slagging characteristics in a 300 kW test furnace:Effect of deposition surface temperature[J]. Ind Eng Chem Res, 2014, 53(17):7233-7246. doi: 10.1021/ie4041516
[8]	WU X J, ZHANG X, YAN K, CHEN N, ZHANG J W, XU X Y, DAI B Q, ZHANG J, ZHANG L. Ash deposition and slagging behavior of Chinese Xinjiang high-alkali coal in 3 MW th pilot-scale combustion test[J]. Fuel, 2016, 181:1191-1202. doi: 10.1016/j.fuel.2016.03.069
[9]	杨涛, 李文广, 吴莎, 张兰, 王学斌, 谭厚章.新疆高钙钠煤燃烧设备结焦机理研究[J].燃料化学学报, 2015, 43(11):1320-1326. doi: 10.3969/j.issn.0253-2409.2015.11.006 YANG Tao, LI Wen-guang, WU Sha, ZHANG Lan, WANG Xue-bin, TAN Hou-zhang. Study on fouling mechanism in a boiler burning Xinjiang coal with high content of calcium and sodium[J]. J Fuel Chem Technol, 2015, 43(11):1320-1326. doi: 10.3969/j.issn.0253-2409.2015.11.006
[10]	魏博, 谭厚章, 王学斌, 胡中发, 王毅斌, 阮仁晖.准东煤灰沉积与无机元素迁徙特性研究[J].工程热物理学报, 2016, 37(8):1783-1788. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=QKC20162016082900012841 WEI Bo, TAN Hou-zhang, WANG Xue-bin, HU Zhong-fa, WANG Yi-bin, RUAN Ren-hui. Ash deposition and inorganic element transformation during zhundong coal combustion[J]. J Eng Thermophys, 2016, 37(8):1783-1788. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=QKC20162016082900012841
[11]	WEI B, TAN H Z, WANG Y B, WANG X B, YANG T, RUAN R H. Investigation of characteristics and formation mechanisms of deposits on different positions in full-scale boiler burning high alkali coal[J]. Appl Therm Eng, 2017, 119:449-458. doi: 10.1016/j.applthermaleng.2017.02.091
[12]	LI G D, LI S Q, HUANG Q, YAO Q. Fine particulate formation and ash deposition during pulverized coal combustion of high-sodium lignite in a down-fired furnace[J]. Fuel, 2015, 143(44):430-437. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=76fac6963b9ea29287adfe61e87842e3
[13]	陈晓东, 孔令学, 白进, 白宗庆, 李文.高温气化条件下Na₂O对煤灰中矿物质演化行为的影响[J].燃料化学学报, 2016, 44(3):263-272. doi: 10.3969/j.issn.0253-2409.2016.03.002 CHEN Xiao-dong, KONG Ling-xue, BAI Jin, BAI Zong-qing, LI Wen. Effect of Na₂O on mineral transformation of coal ash under high temperature gasification condition[J]. J Fuel Chem Technol, 2016, 44(3):263-272. doi: 10.3969/j.issn.0253-2409.2016.03.002
[14]	韩克鑫, 黄镇宇, 王智化, 周俊虎.准东煤灰渣烧结熔融过程中钠基化合物作用机理研究[J].燃料化学学报, 2015, 43(1):22-26. doi: 10.3969/j.issn.0253-2409.2015.01.004 HAN Ke-xin, HUANG Zhen-yu, WANG Zhi-hua, ZHOU Jun-hu. Action mechanism of sodium compounds in Zhundong coal ash on the process of sintering and fusion[J]. J Fuel Chem Technol, 2015, 43(1):22-26. doi: 10.3969/j.issn.0253-2409.2015.01.004
[15]	QI X B, SONG G L, SONG W J, LU Q G. Influence of sodium-based materials on the slagging characteristics of Zhundong coal[J]. J Energy Inst, 2016, 90(6):914-922. http://cn.bing.com/academic/profile?id=8717b42a51eb9fd7dd5936c9657f27b9&encoded=0&v=paper_preview&mkt=zh-cn
[16]	陈衡, 王云刚, 马海东, 赵钦新.循环流化床锅炉燃用准东煤结渣、沾污分析[J].热能动力工程, 2015, 30(3):431-435. http://d.old.wanfangdata.com.cn/Periodical/rndlgc201503018 CHEN Heng, WANG Yun-gang, MA Hai-dong, ZHAO Qin-xin. Analysis and Study of the Slagging and Contamination of a CFB Boiler Burning Zhundong-originated Coal[J]. J Eng Therm Energy Power, 2015, 30(3):431-435. http://d.old.wanfangdata.com.cn/Periodical/rndlgc201503018
[17]	王礼鹏, 赵永椿, 张军营, 姚斌, 郑楚光.准东煤沾污结渣特性研究[J].工程热物理学报, 2015, 36(6):1381-1385. http://d.old.wanfangdata.com.cn/Periodical/dbdljs201810008 WANG Li-peng, ZHAO Yong-chun, ZHANG Jun-ying, YAO Bin, ZHENG Chu-guang. Research on the slagging and fouling characteristics of Zhundong coal[J]. J Eng Thermophys, 2015, 36(6):1381-1385. http://d.old.wanfangdata.com.cn/Periodical/dbdljs201810008
[18]	杨光, 张彦威, 寇希文, 周志军, 王智化, 周俊虎, 岑可法.燃用准东煤电站锅炉灰沉积形成过程中的矿物演变与热力学模拟[J].燃料化学学报, 2015, 43(10):1182-1187. doi: 10.3969/j.issn.0253-2409.2015.10.005 YANG Guang, ZHANG Yan-wei, KOU Xi-wen, ZHOU Zhi-jun, WANG Zhi-hui, ZHOU Jun-hu, CEN Ke-fa. Mineral conversion and thermodynamic simulation of ash deposition during Zhundong coal combustion in boiler of thermal power plant[J]. J Fuel Chem Technol, 2015, 43(10):1182-1187. doi: 10.3969/j.issn.0253-2409.2015.10.005
[19]	王永贞, 金晶, 刘敦禹, 杨浩然, 翟中媛, 李焕龙. 330MW燃准东煤电站锅炉烟气沿程灰沉积特性研究[J].中国电机工程学报, 2017, 37(21):6373-6380. http://www.cqvip.com/QK/90021X/201721/673632343.html WANG Yong-zhen, JIN Jing, LIU Dun-yu, YANG Hao-ran, ZHAI Zhong-yuan, LI Huan-long. Characterization of ash deposits along the flue gas for Zhundong coal combustion in a 330mw boiler[J]. Proc CSEE, 2017, 37(21):6373-6380. http://www.cqvip.com/QK/90021X/201721/673632343.html
[20]	杨少波, 宋国良, 宋维健, 齐晓宾.不同反应气氛下准东高钠煤中钠的迁移转化与积灰特性[J].燃料化学学报, 2016, 44(9):1051-1058. doi: 10.3969/j.issn.0253-2409.2016.09.004 YANG Shao-bo, SONG Guo-liang, SONG Wei-jian, QI Xiao-bin. Transformation and deposition characteristics of sodium in Zhundong high sodium coal under different reaction atmospheres[J]. J Fuel Chem Technol, 2016, 44(9):1051-1058. doi: 10.3969/j.issn.0253-2409.2016.09.004
[21]	LAWRENCE A, KUMAR R, NANDAKUMAR K, NARAYANAN K. A Novel tool for assessing slagging propensity of coals in PF boilers[J]. Fuel, 2008, 87(6):946-950. doi: 10.1016/j.fuel.2007.07.028
[22]	GUPTA S K, WALL T F, CREELMAN R A, GUPTA R P. Ash fusion temperatures and the transformations of coal ash particles to slag[J]. Fuel Process Technol, 1998, 56(1/2):33-43. http://www.sciencedirect.com/science/article/pii/S0378382097000908
[23]	YAN T G, KONG L X, BAI J, BAI Z Q, LI W. Thermomechanical analysis of coal ash fusion behavior[J]. Chem Eng Sci, 2016, 147:74-82. doi: 10.1016/j.ces.2016.03.016
[24]	KIM J H, KIM G B, JEON C H. Prediction of correlation between ash fusion temperature of ASTM and thermo-mechanical analysis[J]. Appl Therm Eng, 2017, 75(9):1218-1228. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=01ad451d37fddf559af2f6166c6d4539
[25]	QI X B, SONG G L, YANG S B, YANG Z, LYU Q G. Exploration of effective bed material for use as slagging/agglomeration preventatives in circulating fluidized bed gasification of high-sodium lignite[J]. Fuel, 2018, 217:577-586. doi: 10.1016/j.fuel.2017.12.126
[26]	KYI S, CHADWICK B L. Screening of potential mineral additives for use as fouling preventatives in Victorian brown coal combustion[J]. Fuel, 1999, 78(7):845-855. doi: 10.1016/S0016-2361(98)00205-1
[27]	周永刚, 范建勇, 李培, 王炳辉, 赵虹.高碱金属准东煤灰熔融过程的矿物质衍变[J].浙江大学学报(工学版), 2015, 49(8):1559-1564. http://d.old.wanfangdata.com.cn/Periodical/zjdxxb-gx201508022 ZHOU Yong-gang, FAN Jian-yong, LI Pei, WANG Bing-hui, ZHAO Hong. Mineral transmutation of high alkali Zhundong coal in ash melting process[J]. J Zhejiang Univ (Eng Sci), 2015, 49(8):1559-1564. http://d.old.wanfangdata.com.cn/Periodical/zjdxxb-gx201508022
[28]	WANG Y Z, JIN J, LIU D Y, YANG H R, LI S J. Understanding ash deposition for the combustion of Zhundong coal:Focusing on different additives effects[J]. Energy Fuels, 2018, 32(6):7103-7111. doi: 10.1021/acs.energyfuels.8b00384
[29]	FREYER D, VOIGT W, KOHNKE K. The phase diagram of the system Na₂SO₄ -CaSO₄[J]. Eur J Sol State Inor, 1998, 35(s1/11):595-606.
[30]	SONG G L, YANG S B, SONG W J, QI X B. Release and transformation behaviors of sodium during combustion of high alkali residual carbon[J]. Appl Therm Eng, 2017, 122:285-296. doi: 10.1016/j.applthermaleng.2017.04.139