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Li C, Liu G, Qin S, Zhu T, Song J, Xu W. Emission reduction of PCDD/Fs by flue gas recirculation and activated carbon in the iron ore sintering. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 327:121520. [PMID: 36990339 DOI: 10.1016/j.envpol.2023.121520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 03/12/2023] [Accepted: 03/26/2023] [Indexed: 06/19/2023]
Abstract
One of the main sources of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the environment is the sintering of iron ore. Both flue gas recirculation (FGR) and activated carbon (AC), which have the impact of decreasing both PCDD/Fs and conventional pollutants (NOx, SO2, etc.), are significant technologies for the abatement of PCDD/Fs from the sintering exhaust gas. This work involved the first measurement of PCDD/Fs emissions during FGR and a thorough analysis of the impact of PCDD/Fs reduction following the coupling of FGR and AC technologies. According to the measured data, the ratio of PCDFs to PCDDs in the sintered flue gas was 6.8, indicating that during the sintering process, the PCDD/Fs were primarily produced by de novo synthesis. Further investigation revealed that FGR initially removed 60.7% of PCDD/Fs by returning it to the high temperature bed, and AC further removed 95.2% of the remaining PCDD/Fs through physical adsorption. While AC is better at removing PCDFs and can efficiently remove tetra-to octa-chlorinated homologs, FGR is more effective at removing PCDDs and has higher removal efficiency for hexa-to octa-chlorinated PCDD/Fs. Together, they complement each other with a removal rate of 98.1%. The study's findings are instructional for the process design of combining FGR and AC technologies to reduce PCDD/Fs in the sintered flue gas.
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Affiliation(s)
- Chaoqun Li
- CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing, 100190, China
| | - Guorui Liu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O.Box 2871, Beijing, 100085, China
| | - Shuai Qin
- CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing, 100190, China; China University of Petroleum, Beijing, 102249, China
| | - Tingyu Zhu
- CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing, 100190, China
| | - Jianfei Song
- China University of Petroleum, Beijing, 102249, China
| | - Wenqing Xu
- CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing, 100190, China.
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Wu Y, Fan X, Ji Z, Gan M, Zhou H, Li H, Chen X, Zhao Y, Zhang R, Lai R. Investigation on the application of by-product steam in iron ore sintering: performance and function mechanism. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:62698-62709. [PMID: 35411520 DOI: 10.1007/s11356-022-20059-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Accepted: 03/29/2022] [Indexed: 06/14/2023]
Abstract
The combustion-supporting effect of steam to coke breeze in sintering has the potential to improve sinter quality and reduce pollutants emissions. The results show that increasing the by-product steam injection concentration (0.32-0.47vol%) and prolonging the injection time (5 min) within a proper range (10-15 min) can improve sinter quality. 2.13kgce/t-sinter of the fuel consumption was decreased by reducing coke breeze usage from 5.60 to 5.45% under the recommended parameters, with 15.16% decrease of CO in sintering waste gas. By comparing experimental data with thermodynamic calculations, although the reaction between CO and steam can reduce CO emission and generate H2, steam tends to react with coke breeze to generate H2 and CO (react at 674℃), and OH radical produced by H2 which can reduce the activation energy of CO oxidation reaction is the key to reducing pollutant emissions. The potential economic benefit of steam injection technology was calculated based on a 360m2 sintering machine (the annual sinter output is 3.2million tons), excluding the equipment modification and steam injection cost of $300,000; a profit of $737491.2 per year or 0.23 dollars per ton sinter can be achieved. Therefore, low-carbon and cleaner iron ore sintering production can be realized through applying by-product steam.
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Affiliation(s)
- Yufeng Wu
- School of Resource Processing and Bioengineering, Central South University, 932 Lushan South Road, Yuelu District, Changsha City, Hunan Province, China
| | - Xiaohui Fan
- School of Resource Processing and Bioengineering, Central South University, 932 Lushan South Road, Yuelu District, Changsha City, Hunan Province, China
| | - Zhiyun Ji
- School of Resource Processing and Bioengineering, Central South University, 932 Lushan South Road, Yuelu District, Changsha City, Hunan Province, China.
| | - Min Gan
- School of Resource Processing and Bioengineering, Central South University, 932 Lushan South Road, Yuelu District, Changsha City, Hunan Province, China
| | - Haoyu Zhou
- School of Resource Processing and Bioengineering, Central South University, 932 Lushan South Road, Yuelu District, Changsha City, Hunan Province, China
- MCC Changtian International Engineering Co., Ltd, No. 7 Jieqing Road, Meixi Lake, Yuelu District, Changsha, Hunan, People's Republic of China
| | - Haorui Li
- School of Resource Processing and Bioengineering, Central South University, 932 Lushan South Road, Yuelu District, Changsha City, Hunan Province, China
| | - Xuling Chen
- School of Resource Processing and Bioengineering, Central South University, 932 Lushan South Road, Yuelu District, Changsha City, Hunan Province, China
| | - Yuanjie Zhao
- School of Resource Processing and Bioengineering, Central South University, 932 Lushan South Road, Yuelu District, Changsha City, Hunan Province, China
| | - Rongchang Zhang
- School of Resource Processing and Bioengineering, Central South University, 932 Lushan South Road, Yuelu District, Changsha City, Hunan Province, China
| | - Ruisi Lai
- School of Resource Processing and Bioengineering, Central South University, 932 Lushan South Road, Yuelu District, Changsha City, Hunan Province, China
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Zhang L, Li B, Liu C, Tian H, Hong M, Yin X, Feng X. NO reduction with CO over a highly dispersed Mn/TiO 2catalyst at low temperature: a combined experimental and theoretical study. NANOTECHNOLOGY 2021; 32:505717. [PMID: 34500443 DOI: 10.1088/1361-6528/ac2538] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 09/08/2021] [Indexed: 06/13/2023]
Abstract
A highly dispersed Mn/TiO2catalyst, which has high efficiency for NO conversion with CO and almost completed N2selectivity at a low-temperature range (350-550 K), was investigated using experimental and DFT theoretical calculation. The characterization results illustrated that the catalyst assembled with nanoparticles and the Mn doping into the TiO2surface lattice led to the formation of Mn-O-Ti configuration, which enhanced the dispersion of Mn on the body of TiO2. The DFT study mapped out the complete catalytic cycle, including reactants adsorption, oxygen vacancy generation, N2O intermediates formation, N2formation in Eley-Rideal (ER), Langmuir-Hinshelwood, and termolecular Eley-Rideal mechanisms. With thermodynamic and kinetic analysis combined with experimental results, the ER reaction process was considered to be the fundamental mechanism over the highly dispersed Mn/TiO2catalyst. The calculation results indicated that N2O was a significant intermediate. However, the rapid N2O reduction process led to high N2selectivity. The rate-limiting step was the deoxygenation step of NO-MnOv/TiO2from N-O bond scission. The active site Mn-Ovpair embedded in Mn/TiO2was responsible not only for the formation of N-Mn/TiO2in the ER-1 step but also for the N2O deoxygenation process to make the final product N2in the ER-2 step. The synergetic effect between Mn 3d electron and the oxygen vacancy of TiO2were responsible for the catalytic activity of Mn/TiO2.
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Affiliation(s)
- Lilei Zhang
- College of Chemistry and Chemical Engineering, Luoyang Normal University, Luoyang 471934, People's Republic of China
| | - Botan Li
- College of Chemistry and Chemical Engineering, Luoyang Normal University, Luoyang 471934, People's Republic of China
| | - Chunyan Liu
- College of Chemistry and Chemical Engineering, Luoyang Normal University, Luoyang 471934, People's Republic of China
| | - He Tian
- College of Chemistry and Chemical Engineering, Luoyang Normal University, Luoyang 471934, People's Republic of China
| | - Manzhou Hong
- Green Catalysis Centre, and College of Chemistry, Zhengzhou University, Zhengzhou 450001, People's Republic of China
| | - Xia Yin
- School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan 430205, People's Republic of China
| | - Xun Feng
- College of Chemistry and Chemical Engineering, Luoyang Normal University, Luoyang 471934, People's Republic of China
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