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过程工程学报 ›› 2023, Vol. 23 ›› Issue (12): 1694-1705.DOI: 10.12034/j.issn.1009-606X.223068

• 研究论文 • 上一篇    下一篇

钙铁复合脱硫剂的制备及其协同脱硫作用

刘洋1,2， 张馨予2， 李洋2， 李长明3， 甘丽娜1*， 余剑2   

  1. 1. 上海理工大学环境与建筑学院，上海 200082 2. 中国科学院过程工程研究所多相复杂系统国家重点实验室，北京 100190 3. 北京工商大学生态环境学院，北京 100048
  • 收稿日期:2023-03-14 修回日期:2023-04-20 出版日期:2023-12-28 发布日期:2024-01-01
  • 通讯作者: 甘丽娜 lngan@usst.edu.cn

Preparation of calcium-iron composite desulfurizer and its synergistic desulfurization effect

Yang LIU1,2,  Xinyu ZHANG2,  Yang LI2,  Changming LI3,  Lina GAN1*,  Jian YU2   

  1. 1. School of Environment and Architecture, Shanghai University of Technology, Shanghai 200082, China 2. State Key Laboratory of Multi-phase Complex System, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China 3. School of Ecology and Environment, Beijing Technology and Business University, Beijing 100048, China
  • Received:2023-03-14 Revised:2023-04-20 Online:2023-12-28 Published:2024-01-01

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摘要： 针对低排量烟气固定床钙基颗粒脱硫剂反应性差、硫容低等关键技术难题，本研究以富羟基铁泥为反应助剂，成功构筑了高活性、大孔径、高硫容的钙铁复合脱硫剂。脱硫性能测试结果表明，脱硫剂钙铁双组分具有强烈的协同脱硫作用，其中含30wt%羟基氧化铁(FeOOH)脱硫剂硫容最佳并优于已报道同类型脱硫剂，高达106 mg SO2/g。通过氮气物理吸附解吸、X射线晶体衍射、扫描电镜、X射线光电子能谱、氢气程序升温还原与热重分析等表征手段，研究揭示钙铁脱硫剂协同脱硫作用的结构基础在于CaO消化过程引入高比表面积铁泥，生成了高活性钙铁界面相(Ca2FeO3Cl·5H2O)，抑制了Ca(OH)2晶粒的生长，形成了多孔、高比表面积(67.36 m2/g)的蓬松状颗粒结构，暴露了更丰富的SO2吸附和反应活性位；而且钙铁脱硫剂FeOOH组分在脱硫过程中分解形成的孔道、水膜和活性Fe3+促进了SO2的扩散、吸附和氧化，进一步强化了SO2的反应和脱除效果。本研究有望能够为中小型锅炉或散排烟气脱硫净化提供一种廉价便捷的净化材料与工艺。

关键词: 氢氧化钙, FeOOH, 脱硫, 催化氧化, 传质

Abstract: In this study, the calcium-iron composite desulfurized with high activity, large pore size, and high sulfur capacity was successfully developed by adopting hydroxyl-rich iron sludge as the structure and reaction additives, investigating the effects of different contents of iron sludge and anions on the desulfurization activity, aiming to address the key technical problems such as poor reactivity and low sulfur capacity of the fixed bed calcium-based particle desulfurized for flue gas with low exhaust emissions, while completing the utilization of red mud. The desulfurization performance test results showed that the calcium-iron dual component desulfurization agent exhibited a strong cooperating desulfurization effect, and the desulfurization performance was significantly higher than that of Ca(OH)2 or FeOOH individually, in which the 30wt% hydroxy iron oxide (FeOOH) desulfurization agent had the optimal sulfur capacity and better than the reported desulfurization agents of the same type, up to 106 mg SO2/g. N2 physisorption desorption, X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, hydrogen temperature-programmed reduction, and thermogravimetric analysis characterization studied reveal that the structural basis of CaO desulfurizer synergistic desulfurization is the introduction of high specific surface area iron sludge during the hydroxylation process of CaO, which generated a highly reactive CaFeO3Cl·5H2O interfacial phase and inhibited the growth of Ca(OH)2 grains. In addition, the rapid evaporation and expansion of internal water during lime hydroxylation results in the formation of a porous, high specific surface area (67.36 m2/g) fluffy particle structure, exposing more abundant SO2 adsorption and reaction active sites, and the pore channels. Water film and active Fe3+ formed by the decomposition of FeOOH component of calcium-iron desulfurized during the desulfurization process effectively promoted the diffusion, adsorption, and oxidation of SO2, further enhancing the reaction and removal of SO2. This study is expected to be able to provide a cheap and convenient purification material and process for the desulfurization and purification of small and medium-sized boilers or bulk exhaust flue gas.

Key words: calcium hydroxide, FeOOH, desulfurization, catalytic oxidation, mass transfer