全部 标题 作者
关键词 摘要

OALib Journal期刊
ISSN: 2333-9721
费用:99美元

查看量下载量

相关文章

更多...
化工学报  2015 

温度和赋存形态对燃煤过程中砷迁移和释放的影响

DOI: 10.11949/j.issn.0438-1157.20150486, PP. 4643-4651

Keywords: 煤燃烧,砷的释放,温度,赋存形态,实验验证,数值分析

Full-Text   Cite this paper   Add to My Lib

Abstract:

选取3个煤阶共6个国内典型煤种,利用水平管式炉在不同温度下进行煤的燃烧实验,研究燃煤过程中砷的迁移和释放特性。利用热分析的相关理论和方法,将煤的热重分析手段运用于煤燃烧过程中砷的质量变化,通过对实验结果进行拟合得到砷的失重曲线和失重速率曲线,并采用逐级化学提取的方法对原煤及不同温度下煤灰中砷的赋存形态进行分析。25~1100℃的实验结果表明:随着温度升高,煤中砷的释放比例逐渐增大,1100℃下砷的释放比例变化范围为30%~67%。不同温度区间下砷的失重速率存在差异,800~900℃区间出现显著的砷失重峰,主要原因是以硫化物形式存在的砷在800~900℃区间发生剧烈的分解/氧化分解。此外,相同温度下褐煤的失重比例和失重速率较大,无烟煤的失重比例和失重速率较小,烟煤则介于无烟煤和褐煤之间。温度升高后,煤中的有机物结合态砷向气相迁移,酸溶态砷和残渣态砷共同作用,减少的砷主要进入气相中,还有一部分向可交换态砷迁移。

References

[1]  Tang Q, Liu G, Yan Z, Sun R. 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.
[2]  Liu Guijian (刘桂建), Peng Zicheng (彭子成), Yang Pingyue (杨萍玥), et al. Changes of trace elements in coal during combustion [J]. Journal of Fuel Chemistry and Technology (燃料化学学报), 2001, 29 (2): 119-123.
[3]  Zhang Kaihua (张凯华), Zhang Kai (张锴), Pan Weiping (潘伟平). Emission characteristics of arsenic and mercury from a 300 MW coal-fired power plant [J]. Journal of Fuel Chemistry and Technology (燃料化学学报), 2013, 41 (7): 839-844.
[4]  Chen Guanyi (陈冠益), Wang Qin (王钦), Yan Beibei (颜蓓蓓). Mobility and enrichment of trace elements in a coal-fired circulating fluidized bed boiler [J]. Journal of Fuel Chemistry and Technology (燃料化学学报), 2013, 41 (9): 1050-1055.
[5]  Tessier A, Campbell P G C, Bisson M. Sequential extraction procedure for the speciation of particulate trace metals [J]. Analytical Chemistry, 1979, 51 (7): 844-851.
[6]  Liu Jing (刘晶), Zheng Chuguang (郑楚光), Zhang Junying (张军营), et al. Study on the speciation of most volatile trace elements in coal [J]. Journal of Combustion Science and Technology (燃烧科学与技术), 2003, 9 (4): 295-299.
[7]  Zeng T, Sarofim A F, Senior C L. Vaporization of arsenic, selenium and antimony during coal combustion [J]. Combustion and Flame, 2001, 126 (3): 1714-1724.
[8]  Bai Xiangfei (白向飞). The distributions, modes of occurrence and volatility of trace elements in coals of china [D]. Beijing: China Coal Research Institute, 2003.
[9]  Kang Y, Liu G, Chou C-L, Wong M H, Zheng L, Ding R. Arsenic in Chinese coals: distribution, modes of occurrence, and environmental effects [J]. Science of the Total Environment, 2011, 412: 1-13.
[10]  Yudovich Y E, Ketris M. Arsenic in coal: a review [J]. International Journal of Coal Geology, 2005, 61 (3): 141-196.
[11]  Guo R, Yang J, Liu Z. Thermal and chemical stabilities of arsenic in three Chinese coals [J]. Fuel Processing Technology, 2004, 85 (8/9/10): 903-912.
[12]  Srinivasachar S, Boni A A. A kinetic model for pyrite transformations in a combustion environment [J]. Fuel, 1989, 68 (7): 829-836.
[13]  Chakraborti N, Lynch D C. Thermodynamic analysis of the As-S-O vapor system [J]. Canadian Metallurgical Quarterly, 1985, 24 (1): 39-45.
[14]  Wang J, Tomita A. A chemistry on the volatility of some trace elements during coal combustion and pyrolysis [J]. Energy & Fuels, 2003, 17 (4): 954-960.
[15]  Contreras M L, Arostegui J M, Armesto L. Arsenic interactions during co-combustion processes based on thermodynamic equilibrium calculations [J]. Fuel, 2009, 88 (3): 539-546.
[16]  Agency E P. Locating and estimating air emissions from sources of arsenic and arsenic compounds. EPA-454/R-98-013 [R]. United States: EPA, 1998.
[17]  Shah P, Strezov V, Prince K, Nelson P F. Speciation of As, Cr, Se and Hg under coal fired power station conditions [J]. Fuel, 2008, 87 (10): 1859-1869.
[18]  Tian H, Lu L, Hao J, Gao J, Cheng K, Liu K, Qiu P, Zhu C. A review of key hazardous trace elements in Chinese coals: abundance, occurrence, behavior during coal combustion and their environmental impacts [J]. Energy & Fuels, 2013, 27 (2): 601-614.
[19]  Clarke L B. The fate of trace elements during coal combustion and gasification: an overview [J]. Fuel, 1993, 72 (6): 731-736.
[20]  Sun Jingxin (孙景信), Jervis R E. Trace elements in coal and their distribution during combustion process [J]. Science in China, Ser. A (中国科学: A辑), 1986, 12 (1): 1287-1294.
[21]  Zhou C, Liu G, Yan Z, Fang T, Wang R. Transformation behavior of mineral composition and trace elements during coal gangue combustion [J]. Fuel, 2012, 97: 644-650.
[22]  Dai Caisheng (戴财胜), Li Fangwen (李方文). Arsenic emission characteristics during fluidized-bed coal combustion [J]. Journal of China Coal Society (煤炭学报), 2005, 30 (1): 109-113.
[23]  Sia S G, Abdullah W H. Enrichment of arsenic, lead, and antimony in Balingian coal from Sarawak, Malaysia: modes of occurrence, origin, and partitioning behaviour during coal combustion [J]. International Journal of Coal Geology, 2012, 101: 1-15.

Full-Text

Contact Us

service@oalib.com

QQ:3279437679

WhatsApp +8615387084133