Influence of Zn in the iron ore sintering flue gas on the removal of NOx and dioxins by V2O5–WO3/TiO2 catalyst

DING Long; QIAN Li-xin; YANG Tao; ZHANG Hong-liang; YU Zheng-wei; ZHANG Xiao-xia; LONG Hong-ming

doi:10.13374/j.issn2095-9389.2020.10.08.001

Volume 43 Issue 8

Aug. 2021

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Article Navigation > Chinese Journal of Engineering > 2021 > 43(8): 1125-1135

DING Long, QIAN Li-xin, YANG Tao, ZHANG Hong-liang, YU Zheng-wei, ZHANG Xiao-xia, LONG Hong-ming. Influence of Zn in the iron ore sintering flue gas on the removal of NOx and dioxins by V2O5–WO3/TiO2 catalyst[J]. Chinese Journal of Engineering, 2021, 43(8): 1125-1135. doi: 10.13374/j.issn2095-9389.2020.10.08.001

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DING Long, QIAN Li-xin, YANG Tao, ZHANG Hong-liang, YU Zheng-wei, ZHANG Xiao-xia, LONG Hong-ming. Influence of Zn in the iron ore sintering flue gas on the removal of NO_x and dioxins by V₂O₅–WO₃/TiO₂ catalyst[J]. Chinese Journal of Engineering, 2021, 43(8): 1125-1135. doi: 10.13374/j.issn2095-9389.2020.10.08.001

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Influence of Zn in the iron ore sintering flue gas on the removal of NO_x and dioxins by V₂O₅–WO₃/TiO₂ catalyst

doi: 10.13374/j.issn2095-9389.2020.10.08.001

1.
School of Metallurgical Engineering, Anhui University of Technology, Ma’anshan 243032, China
2.
Anhui Province Key Laboratory of Metallurgy Engineering & Resources Recycling, Ma’anshan 243002, China

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Corresponding author: E-mail: yaflhm@126.com
Received Date: 2020-10-08
Available Online: 2020-11-26
Publish Date: 2021-08-25

Abstract

Abstract

Iron ore sintering is a process in which fuel, flux, and iron ore powders are mixed and sintered into a block under incomplete melting conditions. The flue gas from iron ore sintering process is one of the largest sources of nitrogen oxide (NO_x) and dioxin emissions in industries. The V₂O₅–WO₃/TiO₂ (VWTi) catalyst can simultaneously remove NO_x and dioxins, but the presence of the complex flue gas results in the deactivation of the catalysts. In response to this challenge, this study carried out experiments for ZnCl₂, ZnO, and ZnSO₄ poisoning over the VWTi catalyst via wet impregnation method. The effects of the different Zn species on the simultaneous removal of NO_x and dioxins (chlorobenzene was used as the simulant for dioxins) by the VWTi catalyst were studied under simulated conditions of the iron ore sintering flue gas. The surface physicochemical properties of the fresh and poisoned catalysts were characterized to reveal the deactivation mechanism, and the regeneration experiments of the poisoned catalysts were investigated. Results showed that deactivation through catalytic denitrification and chlorobenzene (CB) catalytic degradation processes could be observed in different Zn-containing catalysts. The poisoning effect was more obvious with the increase of Zn content, and the effects of deactivation were as follows: ZnCl₂>ZnO>ZnSO₄. Results from physical and chemical analyses indicated that Zn species had a significant influence on the chemical environment of the active substances on the surface of the catalysts. Zn species caused a slight agglomeration of particles on the surface of the catalysts, a decrease in the number of surface acid sites, a reduction in the reducibility of surface V species, and a decrease in the chemisorbed oxygen ratio and the molar ratio of n(V⁵⁺)/n(V⁴⁺). The regeneration experiments confirmed that employing the dilute sulfuric acid solution washing method was effective for recovering the catalytic activity, whereas the water washing method failed to restore the catalytic activity. The mechanism of Zn salt poisoning is as follows: Zn²⁺ reacts with the acid sites V=O and V?OH on the surface of the catalyst to form V?O?Zn, which adversely affects the adsorption of NH₃ and CB, resulting in the catalyst poisoning and deactivation. The ${\rm{SO}}_4^{2-} $ in ZnSO₄ provides a new acidic site for the adsorption and transformation of NH₃ and CB alleviating the poisoning effect. The Cl^? in ZnCl₂ produces HCl as a by-product after the reaction, resulting in more active sites poisoning on the surface of the catalyst and deepening the poisoning effect.
- V₂O₅–WO₃/TiO₂,
- Zn species,
- poisoning,
- NO_x,
- dioxin

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References(31)

References

[1]	Kong M, Liu Q C, Zhou J, et al. Effect of different potassium species on the deactivation of V₂O₅?WO₃/TiO₂ SCR catalyst: Comparison of K₂SO₄, KCl and K₂O. Chem Eng J, 2018, 348: 637 doi: 10.1016/j.cej.2018.05.045
[2]	邢奕, 張文伯, 蘇偉, 等. 中國鋼鐵行業超低排放之路. 工程科學學報, 2021, 43(1):1 Xing Y, Zhang W B, Su W, et al. Research of ultra-low emission technologies of the iron and steel industry in China. Chin J Eng, 2021, 43(1): 1
[3]	閆伯駿, 邢奕, 路培, 等. 鋼鐵行業燒結煙氣多污染物協同凈化技術研究進展. 工程科學學報, 2018, 40(7):767 Yan B J, Xing Y, Lu P, et al. A critical review on the research progress of multi-pollutant collaborative control technologies of sintering flue gas in the iron and steel industry. Chin J Eng, 2018, 40(7): 767
[4]	Yu Y K, He C, Chen J S, et al. Deactivation mechanism of de-NO_x catalyst (V₂O₅?WO₃/TiO₂) used in coal fired power plant. J Fuel Chem Technol, 2012, 40(11): 1359 doi: 10.1016/S1872-5813(13)60003-1
[5]	吳勝利, 張永忠, 蘇博, 等. 影響燒結工藝過程NO_x排放質量濃度的主要因素解析. 工程科學學報, 2017, 39(5):693 Wu S L, Zhang Y Z, Su B, et al. Analysis of main factors affecting NO_x emissions in sintering process. Chin J Eng, 2017, 39(5): 693
[6]	王靜, 沈伯雄, 劉亭, 等. 釩鈦基SCR催化劑中毒及再生研究進展. 環境科學與技術, 2010, 33(9):97 Wang J, Shen B X, Liu T, et al. Deactivation and regeneration of SCR catalyst based on V₂O₅?TiO₂. Environ Sci Technol, 2010, 33(9): 97
[7]	Wang C, Li C M, Li Y J, et al. Destructive influence of cement dust on the structure and DeNO_x performance of V-based SCR catalyst. Ind Eng Chem Res, 2019, 58(43): 19847 doi: 10.1021/acs.iecr.9b04268
[8]	劉建東, 黃張根, 李哲, 等. Ce對Mn/TiO₂/堇青石整體低溫脫硝選擇性催化還原催化劑的改性. 高等學校化學學報, 2014, 35(3):589 Liu J D, Huang Z G, Li Z, et al. Ce modification on Mn/TiO₂/cordierite monolithic catalyst for low-temperature NO_x reduction. Chem J Chin Univ, 2014, 35(3): 589
[9]	Chen L, Li J H, Ge M F. The poisoning effect of alkali metals doping over nano V₂O₅?WO₃/TiO₂ catalysts on selective catalytic reduction of NO_x by NH₃. Chem Eng J, 2011, 170(2-3): 531 doi: 10.1016/j.cej.2010.11.020
[10]	Li X, Li J H, Peng Y, et al. Regeneration of commercial SCR catalysts: probing the existing forms of arsenic oxide. Environ Sci Technol, 2015, 49(16): 9971 doi: 10.1021/acs.est.5b02257
[11]	Dahlin S, Nilsson M, B?ckstr?m D, et al. Multivariate analysis of the effect of biodiesel-derived contaminants on V₂O₅?WO₃/TiO₂ SCR catalysts. Appl Catal B Environ, 2016, 183: 377 doi: 10.1016/j.apcatb.2015.10.045
[12]	Guo R T, Lu C Z, Pan W G, et al. A comparative study of the poisoning effect of Zn and Pb on Ce/TiO₂ catalyst for low temperature selective catalytic reduction of NO with NH₃. Catal Commun, 2015, 59: 136 doi: 10.1016/j.catcom.2014.10.006
[13]	Peng Y, Wang D, Li B et al. Impacts of Pb and SO₂ poisoning on CeO₂?WO₃/TiO₂? SiO₂ SCR catalyst. Environ Sci Technol, 2017, 51(20): 11943 doi: 10.1021/acs.est.7b03309
[14]	Yan L J, Wang F L, Wang P L, et al. Unraveling the unexpected offset effects of Cd and SO₂ deactivation over CeO₂?WO₃/TiO₂ catalysts for NO_x reduction. Environ Sci Technol, 2020, 54(12): 7697 doi: 10.1021/acs.est.0c01749
[15]	Kong M, Liu Q C, Zhu B H, et al. Synergy of KCl and Hg^el on selective catalytic reduction of NO with NH₃ over V₂O₅? WO₃/TiO₂ catalysts. Chem Eng J, 2015, 264: 815 doi: 10.1016/j.cej.2014.12.038
[16]	Qian L X, Chun T J, Long H M, et al. Emission reduction research and development of PCDD/Fs in the iron ore sintering. Process Saf Environ Prot, 2018, 117: 82 doi: 10.1016/j.psep.2018.04.014
[17]	Chun T J, Zhu D Q. New process of pellets-metallized sintering process (PMSP) to treat zinc-bearing dust from iron and steel company. Metall Mater Trans B, 2015, 46(1): 1 doi: 10.1007/s11663-014-0243-4
[18]	紀莎莎, 李曉東, 俞明鋒, 等. V₂O₅?WO₃/TiO₂ 催化劑降解氣相二惡英的研究. 浙江大學學報(工學版), 2014, 48(10):1746 Ji S S, Li X D, Yu M F, et al. Oxidation of PCDD/Fs over V₂O₅?TiO₂-based catalyst. J Zhejiang Univ Eng Sci, 2014, 48(10): 1746
[19]	Yang C C, Chang S H, Hong B Z, et al. Innovative PCDD/F-containing gas stream generating system applied in catalytic decomposition of gaseous dioxins over V₂O₅?WO₃/TiO₂-based catalysts. Chemosphere, 2008, 73(6): 890 doi: 10.1016/j.chemosphere.2008.07.027
[20]	Weng X L, Xue Y H, Chen J K, et al. Elimination of chloroaromatic congeners on a commercial V₂O₅?WO₃/TiO₂ catalyst: The effect of heavy metal Pb. J Hazard Mater, 2020, 387: 121705 doi: 10.1016/j.jhazmat.2019.121705
[21]	Sprenger D, Bach H, Meisel W, et al. XPS study of leached glass surfaces. J Non-Cryst Solids, 1990, 126(1? 2): 111
[22]	Topsoe N Y, Topsoe H, Dumesic J A. Vanadia/titania catalysts for selective catalytic reduction (SCR) of nitric-oxide by ammonia: I. combined temperature-programmed in-situ FTIR and on-line mass-spectroscopy studies. J Catal, 1995, 151(1): 226 doi: 10.1006/jcat.1995.1024
[23]	Alemany L J, Lietti L, Ferlazzo N, et al. Reactivity and physicochemical characterization of V₂O₅?WO₃/TiO₂ de-NO_x catalysts. J Catal, 1995, 155(1): 117 doi: 10.1006/jcat.1995.1193
[24]	Ramis G, Yi L, Busca G. Ammonia activation over catalysts for the selective catalytic reduction of NO_x and the selective catalytic oxidation of NH₃. An FT-IR study. Catal Today, 1996, 28(4): 373 doi: 10.1016/S0920-5861(96)00050-8
[25]	Topsoe N Y. Mechanism of the selective catalytic reduction of nitric oxide by ammonia elucidated by in situ on-line Fourier transform infrared spectroscopy. Science, 1994, 265(5176): 1217 doi: 10.1126/science.265.5176.1217
[26]	Wang J, Wang X, Liu X L, et al. Catalytic oxidation of chlorinated benzenes over V₂O₅/TiO₂ catalysts: The effects of chlorine substituents. Catal Today, 2015, 241: 92 doi: 10.1016/j.cattod.2014.04.002
[27]	Miao J F, Yi X F, Su Q F, et al. Poisoning effects of phosphorus, potassium and lead on V₂O₅?WO₃/TiO₂ catalysts for selective catalytic reduction with NH₃. Catalysts, 2020, 10(3): 345 doi: 10.3390/catal10030345
[28]	Gao F Y, Tang X L, Yi H H, et al. The poisoning and regeneration effect of alkali metals deposed over commercial V₂O₅?WO₃/TiO₂ catalysts on SCR of NO by NH₃. Chin Sci Bull, 2014, 59(31): 3966 doi: 10.1007/s11434-014-0496-y
[29]	Xu L W, Wang C Z, Chang H Z, et al. New insight into SO₂ poisoning and regeneration of CeO₂–WO₃/TiO₂ and V₂O₅–WO₃/TiO₂ catalysts for low-temperature NH₃–SCR. Environ Sci Technol, 2018, 52(12): 7064 doi: 10.1021/acs.est.8b01990
[30]	Madia G, Elsener M, Koebel M, et al. Thermal stability of vanadia-tungsta-titania catalysts in the SCR process. Appl Catal B Environ, 2002, 39(2): 181 doi: 10.1016/S0926-3373(02)00099-1
[31]	Bond G C, Tahir S F. Vanadium oxide monolayer catalysts Preparation, characterization and catalytic activity. App Catal, 1991, 71(1): 1 doi: 10.1016/0166-9834(91)85002-D