Experimental and modeling study on arsenic volatilization during co-combustion of high arsenic lignite and low arsenic bituminous coal

doi:10.11949/j.issn.0438-1157.20160530

Abstract

Abstract:

Arsenic volatilization characteristics during co-combustion of high arsenic lignite and low arsenic bituminous coal were carried out on an isothermal experiment system from 600℃ to 1100℃ at different blending ratios (3:1, 1:1, 1:3). The results showed that with increasing temperature, the arsenic volatilization in single and mixed coals increased gradually. The volatilization ratios of arsenic in mixed coals at various blending ratios were between two single coals, while they were larger than the weighted average values. Combined with isothermal coal combustion curves, it was found that high volatile content in lignite affected the char combustion properties in blended coals, which in turn promoted the volatilization of arsenic. Considering the effects of temperature, coal blending and the difference of coal rank, the arsenic volatilization model during mixed coal combustion was proposed. The model results fit the experimental curves well, which provided a reference for the prediction of arsenic volatility characteristics of blended coals.

Key words: high arsenic lignite, low arsenic bituminous coal, coal blending, volatilization of arsenic, modeling

摘要：

选取典型的高砷褐煤和低砷烟煤，在一维等温燃烧实验台上进行混燃实验，研究温度（600～1100℃）和掺混比（3:1、1:1、1:3）对高砷褐煤混燃砷挥发的影响。实验结果表明：随着温度的升高，单煤及混煤燃烧砷的挥发比例逐渐增大，不同温度下混煤燃烧砷的挥发比例介于两个单煤之间，但砷的挥发比例并不是简单的加权平均，不同温度和掺混比下混煤砷的挥发比例均高于加权值，高砷褐煤中较高的挥发分含量在影响混煤焦炭燃烧的同时也促进了混煤中砷的挥发。因此，提出了综合考虑温度、掺混比和高砷褐煤影响的混煤砷挥发模型，不同温度和掺混比下的模型计算结果与实验值吻合度较好。

关键词: 高砷褐煤, 低砷烟煤, 混燃, 砷挥发, 模型

CLC Number:

X511

LIU Huimin, WANG Chunbo, GUO Yongcheng, ZHANG Yue, HUANG Xingzhi, WANG Jiawei. Experimental and modeling study on arsenic volatilization during co-combustion of high arsenic lignite and low arsenic bituminous coal[J]. CIESC Journal, 2016, 67(10): 4477-4484.

刘慧敏, 王春波, 郭永成, 张月, 黄星智, 王家伟. 高砷褐煤与低砷烟煤混燃砷的挥发特性及模型[J]. 化工学报, 2016, 67(10): 4477-4484.

References 28

[1]	Environmental Protection Agency. Locating and estimating air emissions from sources of arsenic and arsenic compounds:Final Report[R]. United States:EPA, 1998.
[2]	SHAH P, STREZOV V, PRINCE K, et al. Speciation of As, Cr, Se and Hg under coal fired power station conditions[J]. Fuel, 2008, 87(10/11):1859-1869.
[3]	傅丛, 白向飞, 姜英. 中国典型高砷煤中砷与煤质特征之间的关系及砷的赋存状态[J]. 煤炭学报, 2012, 37(1):96-102. FU C, BAI X F, JIANG Y. Discussion on the relationship between the content of arsenic and the coal quality characteristic and the arsenic modes of occurrence in Chinese high arsenic coal[J]. Journal of China Coal Society, 2012, 37(1):96-102.
[4]	HUMS E. Mechanistic effects of arsenic oxide on the catalytic components of DeNOx catalysts[J]. Industrial & Engineering Chemistry Research, 2002, 31(4):1030-1035.
[5]	赵峰华. 煤中有害微量元素分布赋存机制及燃煤产物淋滤实验研究[D]. 北京:中国矿业大学(北京), 1997. ZHAO F H. Study on the mechanism of distributions and occurrences of hazardous minor and trace elements in coal and leaching experiments of coal combustion residues[D]. Beijing:China University of Mining & Technology (Beijing), 1997.
[6]	张微, 王骋, 于光前, 等. 2010年全国饮水型地方性砷中毒监测报告[J]. 中华地方病学杂志, 2012, 31(1):55-59. ZHANG W, WANG C, YU G Q, et al. National monitoring report of drinking-water-born endemic arsenicosis in 2010[J]. Chinese Journal of Endemiology, 2012, 31(1):55-59.
[7]	张念恒, 李达圣, 靳争京, 等. 贵州省燃煤污染型地方性砷中毒病区综合防治后环境介质含砷量分析[J]. 中华地方病学杂志, 2013, 32(1):30-32. ZHANG N H, LI D S, JIN Z J, et al. Analysis of arsenic content in environmental media after implementing comprehensive control measures in coal-burning-borne epidemic arsenism areas of Guizhou province[J]. Chinese Journal of Endemiology, 2013, 32(1):30-32.
[8]	BENNDORF J. Application of efficient methods of conditional simulation for optimising coal blending strategies in large continuous open pit mining operations[J]. International Journal of Coal Geology, 2013, 112(112):141-153.
[9]	BAEK S H, PARK H Y, KO S H. The effect of the coal blending method in a coal fired boiler on carbon in ash and NOx emission[J]. Fuel, 2014, 128(14):62-70.
[10]	徐少波, 曾宪鹏, 于敦喜, 等. 基于大型电厂配煤方案的颗粒物生成实验研究[J]. 煤炭学报, 2015, 40(3):684-689. XU S B, ZENG X P, YU D X, et al. Experimental investigation on particle formation in combustion of coal blends based on a large-scale power plant scheme[J]. Journal of China Coal Society, 2015, 40(3):684-689.
[11]	LOW F, ZHANG L. Arsenic emissions and speciation in the oxy-fuel fly ash collected from lab-scale drop-tube furnace[J]. Proceedings of the Combustion Institute, 2013, 34(2):2877-2884.
[12]	TANG Q, LIU G, YAN Z, et al. Distribution and fate of environmentally sensitive elements (arsenic, mercury, stibium and selenium) in coal-fired power plants at Huainan, Anhui, China[J]. Fuel, 2012, 95:334-339.
[13]	ZHAO Y, ZHANG J, HUANG W, et al. Arsenic emission during combustion of high arsenic coals from Southwestern Guizhou, China[J]. Energy Conversion and Management, 2008, 49(4):615-624.
[14]	刘慧敏, 王春波, 黄星智, 等. 富氧燃烧方式下煤中砷的挥发行为[J]. 化工学报, 2015, 66(12):5079-5087. LIU H M, WANG C B, HUANG X Z, et al. Volatilization of arsenic in coal during oxy-fuel combustion[J]. CIESC Journal, 2015, 66(12):5079-5087.
[15]	张军营, 任德贻, 钟秦,等. CaO对煤中砷挥发性的抑制作用[J]. 燃料化学学报, 2000, 28(3):198-200. ZHANG J Y, REN D Y, ZHONG Q, et al. Restraining of arsenic volatility using lime in coal combustion[J]. Journal of Fuel Chemistry and Technology, 2000, 28(3):198-200.
[16]	JIAO F, NINOMIYA Y, ZHANG L, et al. Effect of coal blending on the leaching characteristics of arsenic in fly ash from fluidized bed coal combustion[J]. Fuel Processing Technology, 2013, 106:769-775.
[17]	WANG M, ZHENG B, WANG B, et al. Arsenic concentrations in Chinese coals[J]. Science of the Total Environment, 2006, 357(s1-3):96-102.
[18]	郑刘根, 刘桂建, 高连芬, 等. 中国煤中砷的含量分布、赋存状态、富集及环境意义[J]. 地球学报, 2006, 27(4):355-366. ZHENG L G, LIU G J, GAO L F, et al. Arsenic in Chinese coals:its abundance, distribution, modes of occurrence, enrichment processes, and environmental significance[J]. Acta Geoscientia Sinica, 2006, 27(4):355-366.
[19]	王春波, 王金星, 雷鸣. 恒温下煤粉/生物质混燃特性及NO释放规律[J]. 煤炭学报, 2013, 38(7):1254-1259. WANG C B, WANG J X, LEI M. Co-combustion characteristics and NO emission characteristics of pulverised coal and biomiss blends at constant temperature[J]. Journal of China Coal Society, 2013, 38(7):1254-1259.
[20]	王春波, 冯涛, 雷鸣. 煤粉等温燃烧挥发分、焦炭耦合作用及同步NO释放规律[J]. 煤炭学报, 2015, 40(3):665-670. WANG C B, FENG T, LEI M. Experimental study on coupling and NO emission of volatiles and coal char during the isothermal combustion of pulverized coal[J]. Journal of China Coal Society, 2015, 40(3):665-670.
[21]	WANG C, ZHOU X, JIA L, et al. Sintering of limestone in calcination/carbonation cycles[J]. Industrial & Engineering Chemistry Research, 2014, 53(42):16235-16244.
[22]	ZENG T, SAROFIM A F, SENIOR C L. Vaporization of arsenic, selenium and antimony during coal combustion[J]. Combustion and Flame, 2001, 126(1):1714-1724.
[23]	刘慧敏, 王春波, 张月, 等. 温度和赋存形态对燃煤过程中砷迁移和释放的影响[J]. 化工学报, 2015, 66(11):4643-4651. LIU H M, WANG C B, ZHANG Y, et al. Effect of temperature and occurrence form of arsenic on its migration and volatilization during coal combustion[J]. CIESC Journal, 2015, 66(11):4643-4651.
[24]	刘晶, 郑楚光, 张军营, 等. 煤中易挥发痕量元素赋存形态的分析方法及实验研究[J]. 燃烧科学与技术, 2003, 9(4):295-299. LIU J, ZHENG C G, ZHANG J Y, et al. Study on the speciation of most volatile trace elements in coal[J]. Journal of Combustion Science and Technology, 2003, 9(4):295-299.
[25]	吕永灿. 混煤燃烧过程中孔隙结构和官能团变化研究[D]. 武汉:华中科技大学, 2009. LÜ Y C. Study on the changes of pore structure and functional group during blended coal combustion[D]. Wuhan:Huazhong University of Science & Technology, 2009.
[26]	LI C Z. Importance of volatile-char interactions during the pyrolysis and gasification of low-rank fuels-a review[J]. Fuel, 2013, 112(3):609-623.
[27]	曾汉才, 姚斌, 邱建荣, 等. 无烟煤与烟煤的混合煤燃烧特性与结渣特性研究[J]. 燃烧科学与技术, 1996, 2(2):181-189. ZENG H C, YAO B, QIU J R, et al. Studies of combustion and slagging characteristics for blended coal with anthracite and bituminous[J]. Journal of Combustion Science and Technology, 1996, 2(2):181-189.
[28]	LIU S, WANG Y, YU L, et al. Volatilization of mercury, arsenic and selenium during underground coal gasification[J]. Fuel, 2006, 85(10/11):1550-1558.