洗选过程对宁武煤中汞迁移和热释放的影响特性

苏银皎; 滕阳; 张锴; 刘轩; 张永红; 冀俊伟

doi:10.19906/j.cnki.JFCT.2021018

洗选过程对宁武煤中汞迁移和热释放的影响特性

doi: 10.19906/j.cnki.JFCT.2021018

苏银皎^1,,
滕阳^1,,
张锴^1, ,,
刘轩¹,
张永红²,
冀俊伟³

1.
华北电力大学热电生产过程污染物监测与控制北京市重点实验室，北京 102206
2.
山西煤炭运销集团太原有限公司，山西太原 030006
3.
中国石油大港油田滨港公司，天津 300280

基金项目: 国家自然科学基金委与山西煤基低碳联合基金重点项目（U1910215）和中央高校基本科研业务费（2019QN020，2019QN019，2020MS008）资助

详细信息

通讯作者:
E-mail: kzhang@ncepu.edu.cn

中图分类号: TQ 53
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出版历程
- 收稿日期: 2020-11-02
- 修回日期: 2020-11-22
- 网络出版日期: 2021-03-19
- 刊出日期: 2021-03-19

Effect of washing process on mercury migration and emission of Ningwu coal

1.
Beijing Key Laboratory of Emission Surveillance and Control for Thermal Power Generation, North China Electric Power University, Beijing 102206, China
2.
Shanxi Coal Transportation and Sales Group Taiyuan Co., Ltd., Taiyuan 030006, China
3.
CNPC Dagang Oilfield Bingang Company, Tianjin 300280, China

Funds: The project was supported by the National Natural Science Foundation of China (U1910215) and the Fundamental Research Funds for the Central Universities (2019QN020, 2019QN019, 2020MS008)

摘要

摘要: 采用逐级化学提取和热分析方法，选取宁武煤田某洗煤厂原煤及洗选产物为研究对象，在汞质量平衡基础上对煤中汞赋存形态进行分类并验证，进而考察了洗选过程对煤中汞迁移行为和热释放的影响特性。结果表明，洗选过程在降低原煤灰分和硫分含量的同时也改变了汞的富集规律，引起了汞的重新分配；样品中汞元素与灰分和硫含量之间的线性相关性分别为0.89和0.99，原煤中汞主要以无机结合态存在，其迁移行为受控于无机矿物质迁移，洗选后矸石总汞绝对含量较原煤增加了322.8%，而精煤汞含量降低至原煤的40%，汞脱除率达到56.4%；洗煤产物中汞富集程度的差异与其在原煤中赋存形态密切相关，其中，矸石中硫化物结合态汞的占比高达56.6%，而精煤和煤泥中有机结合态汞较原煤中均有所提高；相同温度下汞在煤泥中释放率最大，矸石中最小，所有样品中汞至650 ℃均接近完全析出；煤中汞热释放特性也与其赋存形态密切相关，不同热解温度段汞热释放行为由煤中汞的固有赋存形态所决定，其中，有机结合态汞随有机质分解在300 ℃已大量逸出，而硫化物结合态汞分解温度主要为400−600 ℃。
- 煤炭洗选 /
- 汞 /
- 赋存形态 /
- 迁移行为 /
- 分布 /
- 释放特性 /
- 热解 /
- 污染
Abstract: Based on the mercury (Hg) mass balance, a sequential-chemical-extraction method and the thermal analysis technique were used to investigate the occurrence forms of mercury in coal and the effect of washing process on the Hg migration and emission characteristics using Ningwu coal and its washery products. The experimental results show that the ash content and sulfur content reduce in the cleaned coal and Hg is enriched in the gangue, causing an Hg redistribution in the washery products. The linear correlation coefficients of Hg content with ash and sulfur are 0.89 and 0.99, respectively. Hg mainly exists as an inorganic bound state in the raw coal, so its migration behavior is determined by the transfer of inorganic minerals during the washing process. Gangue shows the highest mass increase in the Hg content by 322.8% compared to the raw coal, while the content of Hg in cleaned coal decreases to 40% of that in raw coal with the removal efficiency of 56.4%. The difference of mercury enrichment degree in coal washery products is closely related to its occurrence form in raw coal, in which the proportion of sulfide-bound mercury in gangue is as high as 56.6%, while the organic bound mercury in cleaned coal and slime is higher than that in raw coal. Furthermore, Hg in all samples has been completely released at 650 ℃ during pyrolysis process. Hg has the highest release ratio in slime and the lowest one in gangue at the same pyrolysis temperature. The release characteristics of mercury in coal is also closely related to its occurrence forms, which determines the Hg release behavior at different temperatures. The organic bound mercury escapes in large quantities at 300 ℃ with the decomposition of organic matter, while the decomposition temperature of sulfide bound mercury mainly concentrates at 400−600 ℃.
- coal preparation /
- mercury /
- occurrence form /
- migration behavior /
- distribution /
- emission characteristics /
- pyrolysis /
- pollution

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图 1 热解实验装置示意图

Figure 1 Schematic diagram of the pyrolysis experimental system

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图 2 总汞在洗煤产物中的分配

Figure 2 Mass percentage of total mercury in coal washery products

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图 3 灰分、硫分和总汞在洗煤产物中的迁移

Figure 3 Migration of ash, sulfur and mercury in coal washery products

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图 4 洗煤产物中不同形态汞的相对含量

Figure 4 Relative contents of different species of mercury in raw coal and washery products

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图 5 样品的热失重特性和汞释放特性曲线

Figure 5 Mass loss characteristics and Hg emission characteristics of samples during pyrolysis

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图 6 煤及不同温度热解焦中汞的形态分布

Figure 6 Occurrence forms of mercury in raw coal, washery products and the chars at different temperatures

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表 1 样品的工业分析以及硫和汞含量

Table 1 Proximate analysis, sulfur and mercury content of samples

Sample	Proximate analysis w_ad/%				S content/%	Hg content/(ng·g⁻¹)
Sample	M	A	V	FC	S content/%	Hg content/(ng·g⁻¹)
Raw coal	1.36	52.74	16.96	28.94	1.37	317.9
Cleaned coal	1.29	40.23	21.18	37.30	0.82	138.7
Middling coal	1.37	51.71	17.90	29.02	1.26	263.7
Gangue	1.45	74.79	10.56	13.20	3.06	1344.0
Slime	2.40	38.55	20.64	38.41	1.05	186.9

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参考文献(40)

[1]	代世峰, 唐跃刚, 常春祥, 张义忠, 李薇薇. 开滦煤洗选过程中稀土元素的迁移和分配特征[J]. 燃料化学学报,2005,33(4):416−420. DAI Shi-feng, TANG Yue-gang, CHANG Chun-xiang, ZHANG Yi-zhong, LI Wei. Migration and distribution of rare earth elements during washing process of Kailuan coals[J]. J Fuel Chem Technol,2005,33(4):416−420.
[2]	朱振武, 禚玉群. 煤炭洗选中有害痕量元素的迁移与脱除[J]. 煤炭学报,2016,41(10):2434−2440. ZHU Zhen-wu, ZHUO Yu-qun. Migration and removal of toxic trace elements during coal washing[J]. J China Coal Soc,2016,41(10):2434−2440.
[3]	LUTTRELL G H, KOHMUENCH J N, YOON R H. An evaluation of coal preparation technologies for controlling trace element emissions[J]. Fuel Process Technol,2000,65-66:407−422. doi: 10.1016/S0378-3820(99)00107-1
[4]	LIU H Y, YU D, YANG W, FENG L. The effect of mercury occurrence on mercury rejection during coal preparation[J]. Int J Coal Prep Util,2011,31(1):20−31. doi: 10.1080/19392699.2010.534516
[5]	王文峰, 秦勇, 宋党育. 煤中有害元素的洗选洁净潜势[J]. 燃料化学学报,2003,31(4):295−299. WANG Wen-feng, QIN Yong, SONG Dang-yu. Cleaning potential of hazardous elements during coal washing[J]. J Fuel Chem Technol,2003,31(4):295−299.
[6]	WANG W F, QIN Y, WANG J Y, LI J. Partitioning of hazardous trace elements during coal preparation[J]. Procedia Earth Planet Sci,2009,1(1):838−844. doi: 10.1016/j.proeps.2009.09.131
[7]	ZHOU C C, LIU G J, YAN Z C, FANG T, WANG R W. Transformation behavior of mineral composition and trace elements during coal gangue combustion[J]. Fuel,2012,97:644−650. doi: 10.1016/j.fuel.2012.02.027
[8]	ZHOU C C, LIU G J, FANG T, WU D, LAM P K. Partitioning and transformation behavior of toxic elements during circulated fluidized bed combustion of coal gangue[J]. Fuel,2014,135(1):1−8.
[9]	WANG S B, LUO K L, WANG X, SUN Y Z. Estimate of sulfur, arsenic, mercury, fluorine emissions due to spontaneous combustion of coal gangue: An important part of Chinese emission inventories[J]. Environ Pollut,2016,209(2):107−113.
[10]	冯立品, 路迈西, 刘红缨, 贾晋炜, 苏立. 汞在选煤过程中的迁移规律研究[J]. 洁净煤技术,2008,14(4):16−8, 21. FENG Li-ping, LU Mai-xi, LIU Hong-yin, JIA Jin-wei, SU Li. Study on the transport of mercury during coal preparation[J]. Clean Coal Technol,2008,14(4):16−8, 21.
[11]	宋党育, 张晓逵, 张军营, 郑楚光. 煤中有害微量元素的洗选迁移特性[J]. 煤炭学报,2010,35(7):1170−1176. SONG Dang-Yu, ZHANG Xiao-kui, ZANG Jun-yin, ZHEN Chu-guang. Migration characteristics of hazardous trace elements in coal in the process of flotation[J]. J China Coal Soc,2010,35(7):1170−1176.
[12]	葛涛. 淮南煤中汞的分布与赋存[J]. 安徽理工大学学报(自然科学版),2017,37(1):6−10. GE Tao. The Research into the distribution characteristics & occurrence state of the mercury in the coal of huainan city[J]. J A Univ Sci Technol (Nat Sci Ed),2017,37(1):6−10.
[13]	CHENG X J, SHI L, LIU Q Y, LIU Z Y. Heat effects of pyrolysis of 15 acid washed coals in a DSC/TGA-MS system[J].Fuel, 2020, 268(15): 117325.
[14]	柴发合, 薛志钢, 支国瑞, 杜谨宏, 罗陨飞, 任彦波, 叶建东. 农村居民散煤燃烧污染综合治理对策[J]. 环境保护,2016,44(6):15−19. CHAI Fa-he, XUE Zhi-gang, ZHI Guo-rui, DU Jin-hong, LUO Yun-fei, REN Yan-bo, YE Jian-dong. Complex control measures of rural coal combustion pollution[J]. Environ Protect,2016,44(6):15−19.
[15]	XU W Q, SHAO M P, YANG Y, LIU R H, WU Y H, ZHU T Y. Mercury emission from sintering process in the iron and steel industry of China[J]. Fuel Process Technol,2017,159(5):340−344.
[16]	ZHU Y C, HAN X J, HUANG Z G, HOU Y Q, GUO Y P, WU M H. Superior activity of CeO2 modified V2O5/AC catalyst for mercury removal at low temperature[J]. Chem Eng J,2018,337(4):741−749.
[17]	TIAN H Z, WANG Y, XUE Z G, QU Y P, CHAI F H, HAO J M. Atmospheric emissions estimation of Hg, As, and Se from coal-fired power plants in China, 2007[J]. Sci Total Environ,2011,409(16):3078−3081. doi: 10.1016/j.scitotenv.2011.04.039
[18]	LIU Q Y, LIU Z Y. Carbon supported vanadia for multi-pollutants removal from flue gas[J]. Fuel,2013,108(6):149−158.
[19]	刘玲, 段钰锋, 王运军, 王卉, 尹建军. 两种煤在热解过程中汞的析出和形态分布实验研究[J]. 燃料化学学报,2010,38(2):134−139. doi: 10.1016/S1872-5813(10)60026-6 LIU Lin, DUAN Yu-feng, WANG Yun-jun, WANG Hui, YIN Jian-jun. Experimental study on mercury release behavior and speciation during pyrolysis of two different coals[J]. J Fuel Chem Technol,2010,38(2):134−139. doi: 10.1016/S1872-5813(10)60026-6
[20]	STREZOV V, EVANS T, ZIOLKOWSKI A, SHAH P, NELSON P F. The effect of reducing conditions and temperature on mercury release from coal[J]. Energ Sources Part A,2010,32(18):1712−1719. doi: 10.1080/15567030902882901
[21]	高明刚, 刘永卓, 张欣涛, 宋鸣航, 郭庆杰. 铁基载氧体对煤中汞释放行为的影响[J]. 化工进展,2019,38(S1):240−246. GAO Ming-gang, LIU Yong-zhuo, ZHANG Xin-tao, SONG Min-hang, GUO Qin-jie. Effects of Fe-based oxygen carriers on mercury release behavior from coal[J]. Chem Ind Eng Prog,2019,38(S1):240−246.
[22]	苏银皎刘轩, 李丽锋, 李晓航, 姜平, 滕阳, 张锴. 三类煤阶煤中汞的赋存形态分布特征[J]. 化工学报,2019,70(4):1559−1566. SU Yin-jiao, LIU Xuan, LI Li-feng, LI Xiao-hang, JIANG Ping, TENG Yang, ZHANG Kai. The distribution characteristics of Mercury Speciation in Coals with Three Different Ranks[J]. J Chem Ind Eng,2019,70(4):1559−1566.
[23]	Method 29 - Determination of Metals Emissions from Stationary Sources[M]. United States: United States Environmental Protection Agency, 2009.
[24]	边静虹, 白宏涛, 李文超, 徐鹤. 典型煤化工企业硫代谢特征及其质量平衡[J]. 环境科学学报,2017,37(7):2805−2813. BIAN Jing-hong, BAI Hong-tao, LI Wen-chao, XU He. Characteristics of sulfur metabolism and mass balance of a typical coal chemical enterprise[J]. J Environ Sci China,2017,37(7):2805−2813.
[25]	ZHAI J D, GUO S Q, WEI X X, CAO Y Z, GAO L B. Characterization of the modes of occurrence of mercury and their thermal stability in coal gangues[J]. Energy Fuels,2015,29(12):8239−8245. doi: 10.1021/acs.energyfuels.5b01406
[26]	ZHENG L G, LIU G J, QI C C, ZHANG Y, WONG M H. The use of sequential extraction to determine the distribution and modes of occurrence of mercury in Permian Huaibei coal, Anhui Province, China[J]. Int J Coal Geol,2008,73(2):139−155. doi: 10.1016/j.coal.2007.04.001
[27]	ZHENG L G, LIU G J, CHOU C L. Abundance and modes of occurrence of mercury in some low-sulfur coals from China[J]. Int J Coal Geol,2008,73(1):19−26. doi: 10.1016/j.coal.2007.05.002
[28]	潘金禾, 周长春, 丛龙斐, 刘铖, 耿焕国, 刘浩, 汤大山. 长滩煤中汞元素赋存状态及洗选中迁移规律[J]. 煤炭技术,2016,35(12):304−306. PAN Jin-he, ZHOU Chang-chun, CONG Long-fei, LIU Cheng, GENG Huan-guo, LIU Hao, TANG Da-shan. Mercury in Changtan Coal: Modes of Occurrence and Its Removal Laws during Coal Separation[J]. Coal Technol,2016,35(12):304−306.
[29]	WANG W F, QIN Y, QIAN F C, YE L F, HAO W D, LI Y, JIN F L. Partitioning of elements from coal by different solvents extraction[J]. Fuel,2014,125(1):73−80.
[30]	ZHAO Y Y, ZENG F G, LIANG H Z, TANG Y G, LI M F, XIANG J H, WEN X T. Chromium and vanadium bearing nanominerals and ultra-fine particles in a super-high-organic-sulfur coal from Ganhe coalmine, Yanshan Coalfield, Yunnan, China[J]. Fuel,2017,203(1):832−842.
[31]	QUIVK W J, IRONS R M A. Trace element partitioning during the firing of washed and untreated power station coals[J]. Fuel, 2002, 81(5): 665-72.
[32]	吕帅, 吕国钧, 蒋旭光, 池涌, 严建华, 岑可法, 余学海, 廖海燕, 赵华. 印尼褐煤湿煤末(煤泥)热解和燃烧特性及动力学分析[J]. 煤炭学报,2014,39(3):554−561. LV Shuai, LV Guo-jun, JIANG Xu-guang, CHI Yong, YAN Jian-hua, CEN Ke-fa, YU Xue-hai, LIAO Hai-yan, ZHAO Hua. Pyrolysis/combustion characteristics and kinetic analysis of Indonesia lignite sludge[J]. J China Coal Soc,2014,39(3):554−561.
[33]	李天涛郭飞强, 王岩, 郭成龙, 董玉平. 微型流化床内松木屑和煤泥等温混合热解特性[J]. 化工学报,2017,68(10):3923−3933. LI Tian-tao, GUO Fei-qiang, WANG Yan, GUO Cheng-long, DONG Yu-ping. Characterization of co-pyrolysis of pine sawdust and coal slime under isothermal conditions in micro fluidized bed reactor[J]. J Chem Ind Eng,2017,68(10):3923−3933.
[34]	谢克昌. 煤的结构与反应性[M]. 北京: 科学出版社, 2002. XIE Ke-chang. Coal Structure and Its Reactivity[M]. Beijing: China Science Publishing & Media Ltd., 2002.
[35]	GARCIA L F, HAMPARTSOUMIAN E, WILLIAMS A. Determination of sulfur release and its kinetics in rapid pyrolysis of coal[J]. Fuel,1995,74(7):1072−1079. doi: 10.1016/0016-2361(95)00049-B
[36]	吕海亮, 陈皓侃, 李文, 李保庆. 铁岭煤中重金属元素的赋存形态及其在热解过程中的挥发行为研究[J]. 燃料化学学报, 2004, 32(2): 140−145. LV Hai-liang, CHEN Hao-kan, LI Wen, LI Bao-qing. Occurrences of trace metals in Tieling coal and their volatility behaviors during pyrolysis[J]. J Fuel Chem Technol, 2004, 32(2): 140−145.
[37]	LUO G Q, YAO H, XU M H, RAJENDA G, XU G H. Identifying modes of occurrence of mercury in coal by temperature programmed pyrolysis[J]. Proc Combust Inst,2011,33(2):2763−2769. doi: 10.1016/j.proci.2010.06.108
[38]	GUO S Q, ZHANG L C, NIU X R, GAO L B, CAO Y Z, WEI X X, LI X. Mercury release characteristics during pyrolysis of eight bituminous coals[J]. Fuel,2018,222(15):250−257.
[39]	KUCU S, KADIOGLU E. Desulphurization of some Turkish lignites by pyrolysis[J]. Fuel,1988,67(6):867−870. doi: 10.1016/0016-2361(88)90165-2
[40]	YANG N N, GUO H Q, LIU F R, ZHANG H, HU Y F, HU R S. Effects of atmospheres on sulfur release and its transformation behavior during coal thermolysis[J]. Fuel,2018,215(1):446−453.