洁净煤技术

2020, v.26;No.128(04) 190-195

[打印本页] [关闭]
本期目录(Current Issue) | 过刊浏览(Past Issue) | 高级检索(Advanced Search)

气氛对氧化物吸附气相砷的影响及机理分析
Effects of atmosphere on gas-phase arsenic adsorption by oxides and mechanism analysis

何梓谦;余圣辉;张成;许豪;方庆艳;陈刚;
HE Ziqian;YU Shenghui;ZHANG Cheng;XU Hao;FANG Qingyan;CHEN Gang;State Key Laboratory of Coal Combustion,Huazhong University of Science and Technology;

摘要(Abstract):

燃煤是有害重金属砷进入大气环境的主要途径,通过矿物质氧化物吸附气相砷是炉内控制砷减排的有效方式。但燃煤烟气中含有大量酸性气体,包括CO_2、HCl、SO_2等,会与矿物质氧化物结合,占据吸附剂活性位点,减少气相砷的吸附容量。为了探究烟气中不同酸性气氛对氧化物吸附气相砷的影响特性,选取燃煤飞灰中部分矿物质氧化物CaO、MgO、Fe_2O_3为吸附剂,在两段式固定床反应器中开展700/900℃模拟烟气气氛、O_2/CO_2气氛及含有HCl、SO_2气氛的模拟烟气条件下氧化物吸附气相砷试验。样品吸附砷含量经HCl酸液提取后由原子荧光光度计测量,吸附剂比表面积和孔隙结构特性由BET分析获得,样品微观形貌经SEM分析获得。结果表明,CaO对气相砷的吸附效果最好,其次是MgO,900℃模拟烟气中CaO和MgO吸附气相砷量高于700℃烟气,而Fe_2O_3在700℃吸附气相砷较多。O_2/CO_2气氛下,MgO和CaO对气相砷的吸附量少于相应燃烧气氛,而Fe_2O_3的气相砷吸附量高于模拟烟气气氛。酸性气氛对氧化物吸附气相砷的影响与温度和氧化物种类有关:O_2/CO_2气氛对CaO和MgO吸附气相砷起抑制作用,对Fe_2O_3起促进作用;烟气中HCl抑制CaO吸附气相砷,对MgO和Fe_2O_3吸附气相砷在700℃表现为抑制作用,在900℃时为促进作用;烟气中SO_2对CaO和MgO起抑制作用,对Fe+2O_3无明显影响。CaO、MgO和Fe_2O_3对气相砷以化学吸附为主,Fe_2O_3比表面积最大,对气相砷吸附作用最弱。
Coal combustion is the main way for harmful heavy metal arsenic to enter the atmosphere.It is an effective way to control arsenic emission in-furnace by the adsorption of gaseous arsenic by mineral oxides i. However,coal-fired flue gas contains a large amount of acid gases,including CO_2,HCl,SO_2,etc.,which will combine with mineral oxides,occupy the active site of the sorbents,and thereby reduce the gas-phase arsenic adsorption capacity.In order to understand the effect of acidic gas in flue gas on the adsorption of gaseous arsenic by oxides,some mineral oxides such as Ca O,MgO and Fe_2O_3 were selected as sorbents to carry out gas-phase arsenic adsorption experiments under 700/900 ℃ in simulated flue gas atmosphere.O_2/CO_2 atmosphere and the simulated flue gas containing HCl and SO_2 atmosphere was prepared in a two-stage fixed bed reactor.The arsenic content of the samples was measured by atomic fluorescence spectrometer after extraction with HCl solution,the specific surface area and the pore structure of the adsorbent were analyzed by BET,and the microstructure of the sample was obtained by SEM analysis.The results show that Ca O has the best adsorption effect on gas-phase arsenic,followed by MgO.The arsenic adsorption of Ca O and MgO in the 900 ℃ simulated flue gas is higher than that of 700 ℃,while Fe_2O_3 adsorbs more arsenic at 700 ℃ .In the O_2/CO_2 atmosphere,the amount of arsenic adsorbed by MgO and Ca O is less than that of simulated flue gas,while the capacity of gaseous arsenic adsorbed by Fe_2O_3 is higher than that of simulated flue gas.The effect of acidic gas on arsenic adsorption by oxides is related to the temperature and types of oxides.The O_2/CO_2 atmosphere inhibits the adsorption of gas-phase arsenic by Ca O and MgO,and it promotes Fe_2O_3.HCl in simulated flue gas inhibits the adsorption of gas-phase arsenic by Ca O,and it inhibits the adsorption of gaseous arsenic by MgO and Fe_2O_3 at 700 ℃ and promotes at 900 ℃ .SO_2 in the flue gas inhibites Ca O and MgO,but has no significant effect on Fe_2O_3.CaO,MgO and Fe_2O_3 are mainly chemisorbed by gas-phase arsenic,Fe_2O_3 has the largest specific surface area,but the adsorption is the weakest.

关键词(KeyWords): 烟气气氛;气相砷;矿物质氧化物;吸附特性
flue gas atmosphere;gas-phase arsenic;mineral oxides;adsorption characteristics

Abstract:

Keywords:

基金项目(Foundation): 国家重点研发计划资助项目(2018YFB0605105)

作者(Author): 何梓谦;余圣辉;张成;许豪;方庆艳;陈刚;
HE Ziqian;YU Shenghui;ZHANG Cheng;XU Hao;FANG Qingyan;CHEN Gang;State Key Laboratory of Coal Combustion,Huazhong University of Science and Technology;

Email:

DOI: 10.13226/j.issn.1006-6772.19111210

参考文献(References):

文章评论(Comment):

序号(No.) 时间(Time) 反馈人(User) 邮箱(Email) 标题(Title) 内容(Content)
反馈人(User) 邮箱地址(Email)
反馈标题(Title)
反馈内容(Content)
扩展功能
本文信息
服务与反馈
本文关键词相关文章
本文作者相关文章
中国知网
分享