Chemical Industry and Engineering Progress ›› 2018, Vol. 37 ›› Issue (04): 1599-1607.DOI: 10.16085/j.issn.1000-6613.2017-1357

Previous Articles     Next Articles

Effect of flue gas and fly ash components on mercury removal by bromine modified fly ash

LIU Shuai, DUAN Yufeng, CHEN Mingming, ZHAO Shilin, ZHENG Yiwu, LIU Meng   

  1. Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing 210096, Jiangsu, China
  • Received:2017-07-03 Revised:2017-10-16 Online:2018-04-05 Published:2018-04-05

烟气及飞灰组分对溴改性飞灰脱汞特性的影响

柳帅, 段钰锋, 陈明明, 赵士林, 郑逸武, 刘猛   

  1. 东南大学能源与环境学院, 能源热转换及其过程测控教育部重点实验室, 江苏 南京 210096
  • 通讯作者: 段钰锋,男,教授,研究方向为大气污染物控制。
  • 作者简介:柳帅(1992-),男,硕士研究生。E-mail:804704835@qq.com。
  • 基金资助:
    国家重点研发计划(2016YFB0600604)、国家自然科学基金(51576044)、江苏省普通高校研究生科研与实践创新计划(KYCX17-0072)及东南大学优秀博士学位论文培育基金(YBJJ1706)项目。

Abstract: Unburned carbon(UBC) and metal oxides have a certain adsorption and oxidation abilities of mercury. Fly ash has been considered as a cheap and potential mercury removal adsorbent in coal-fired power plant,but the efficiency is to be improved. In this paper,two kinds of fly ash with different contents of UBC were chosen and modified by 1%NH4 Br solution. Effect of flue gas components(O2,SO2 and NO) and metal oxides on mercury removal by the modified fly ash was investigated in fixed-bed reactor,in order to obtain high efficiency mercury removal adsorbent and adsorption mechanism. The results showed that O2 has a little positive effect on the mercury oxidation. SO2 has a certain inhibitory effect. NO promotes the oxidation of Hg0 obviously. Fe2O3 and TiO2 in bromine modified fly ash played a major role in the oxidation of Hg0. The reason was that bromine modification increases the lattice oxygen content of Fe2O3 and TiO2 which promotes the catalytic oxidation of Hg0,and mainly follows the Mars-Maessen mechanism. UBC content of fly ash has a great impact on the removal of Hg0. When the bromide was embedded in the UBC of the fly ash surface,the activity of the neighborhood was enhanced. As a result,the adsorption capacity of the carbonaceous surface to Hg0 was enhanced,and the subsequent reaction was promoted.

Key words: leaching, adsorbents, mercury, fixed-bed, metal oxide

摘要: 燃煤飞灰中的未燃碳(unburned carbon,UBC)和金属氧化物因对汞有一定的吸附和氧化作用而被认为是燃煤电厂廉价的潜在脱汞吸附剂,但效率有待提高。文章选取两种UBC含量不同的飞灰,采用质量分数1%的NH4Br溶液对其浸渍改性,利用固定床汞吸附实验台探究了烟气组分(O2、SO2和NO)以及飞灰中无机金属氧化物对汞吸附和氧化的影响,以期获得高效脱汞吸附剂吸附机理。结果表明,O2对于溴素改性飞灰氧化汞有较小的促进效果,SO2具有一定的抑制作用,NO促进Hg0的氧化效果明显;溴素改性飞灰中的Fe2O3和TiO2对Hg0的氧化起着主要作用,原因在于溴素改性增加了金属氧化物Fe2O3和TiO2中的晶格氧含量,促进了Hg0的催化氧化,主要遵循Mars-Maessen机理。另外,UBC含量对飞灰脱除Hg0的影响很大,溴素嵌入飞灰表面的UBC时,会使其邻域的活性加强,从而增强碳质表面对Hg0的吸附能力,促进了后续反应的进行。

关键词: 浸取, 吸附剂, 汞, 固定床, 金属氧化物

CLC Number: 

京ICP备12046843号-2;京公网安备 11010102001994号
Copyright © Chemical Industry and Engineering Progress, All Rights Reserved.
E-mail: hgjz@cip.com.cn
Powered by Beijing Magtech Co. Ltd