Adsorbents for the adsorption purification of NOx in the ore-sintering flue gas

被引：0

作者：

Liu Y.-S. ^{[1
]}

Wu X.-Y. ^{[1
]}

Li Z.-Y. ^{[1
]}

Yang X. ^{[1
]}

Liu W.-H. ^{[1
]}

Hou H.-Y. ^{[2
]}

Xing Y. ^{[1
]}

Li J.-J. ^{[3
]}

机构：

[1] School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing

[2] HBIS Technology Research InstituteInstitute, Shijiazhuang

[3] College of Resources and Environmental Engineering, Key Laboratory of Karst Georesources and Environment, Ministry of Education, Guizhou University, Guiyang

来源：

Gongcheng Kexue Xuebao/Chinese Journal of Engineering | 2022年 / 44卷 / 11期

关键词：

adsorbent; adsorption; flue gas purification; nitrogen oxide; recovery;

D O I：

10.13374/j.issn2095-9389.2021.11.01.001

中图分类号：

学科分类号：

摘要：

Nitrogen oxides (NOx) are major air pollutants produced by fuel combustion that cause adverse effects on the environment and human health. The deep purification of NOx from flue gases has become a worldwide issue. In China, a rigorous ultra-low emission standard (ULES) of NOx ≤ 50 mg·m–3 has been implemented in the power and steel industries in recent years. NO2 is a valuable chemical feedstock that is worthy of being recycled from flue gas. Adsorption is a promising technology that can achieve deep purification and resource recovery of NOx from industrial flue gas, in which a high-performance NOx adsorbent plays a key role. However, a systematic understanding of NOx adsorbents for practical applications is still lacking. This study compares and analyzes the NOx adsorption and desorption performances of typical practical adsorbents including zeolites, metal oxides, and silica-alumina gels based on the practical need for both NOx purification efficacy and material thermal stability. NOx adsorption capacities, breakthrough curves, uptake curves, and temperature-programmed desorption (TPD) curves were also measured. Results show that compared to Fe –Mn –Ce and 13X as competitive adsorbents, H-ZSM-5_25 showed NOx deep purification (purification efficiency close to 100% before adsorption breakthrough), great NOx adsorption capacity (0.206 mmol·g–1), and high NO2 concentration ratio in desorption, which are likely due to its high NO catalytic oxidation rate and comparable NO2 physical adsorption rate. Regarding the desorption characteristics, H-ZSM-5_25 showed a bimodal TPD desorption peak with a lower desorption temperature (400–470 K) in the low-temperature region. Meanwhile, NO2 is the primary NOx component in the desorbed gas (adsorption-desorption enrichment ratio of NO2 being up to 57), which can easily be recovered using the liquefaction method. Furthermore, by comparing the adsorption performances on the H-ZSM-5 with different silica-to-alumina ratios, the NOx adsorption was found to decrease (from 0.706 to 0.206 mmol·g–1 for H-ZSM-5_25 and from 0.454 to 0.127 mmol·g–1 for H-ZSM-5_38) with increasing temperature (298–398 K). The dependence of the NO2 adsorption on the temperature was more significant for H-ZSM-5_25 compared to H-ZSM-5_38. Compared to H-ZSM-5_38, H-ZSM-5_25 with a lower silica-to-alumina ratio (consequently, more cation sites) rendered greater NO oxidation performance, a potentially higher NO2 adsorption capacity, and a greater decreasing trend of the adsorption capacity with increasing temperature. Results of adsorption kinetic experiments showed that the NOx mass transfer parameters on H-ZSM-5_25 were lower than those on H-ZSM-5_38 with a smaller primary micro pore channel. Results of the current work can provide technical references for economic flue gas denitrification. © 2022 Science Press. All rights reserved.

引用

页码：1860 / 1867

页数：7

共 42 条

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