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Zhang H, Dong Y, Lai Y, Zhang H, Zhang X. Synergistic removal of particles, SO 2, and NO 2 in desulfurized flue gas during condensation. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:27273-27282. [PMID: 33506416 DOI: 10.1007/s11356-020-12192-y] [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: 03/22/2020] [Accepted: 12/21/2020] [Indexed: 06/12/2023]
Abstract
The synergistic removal of multi-pollutants, including particles, SO2, and NO2, is a key concern in the process of flue gas purification, during which the supersaturated environment is an essential premise for the nucleation and deep reduction of particles. The condensation of desulfurized flue gas using heat exchangers can not only recover condensed water and latent heat but also create supersaturated environment to promote the flue gas purification. In this study, an experimental system for desulfurized flue gas condensation is established. The effect and associated mechanism of condensation process on the removal of multi-pollutions are clarified. The results show that particles with an aerodynamic diameter larger than 2.5 μm accounts for 50% in mass proportion. The flue gas temperature drop has positive influence to the increase of the ideal supersaturation degree, which is beneficial for the removal of particles (especially when the aerodynamic diameter is less than 1 μm), SO2, and NO2. The ideal supersaturation degree slightly reduces with the rise of inlet flue gas temperature, which can promote the removal efficiency of small particles, while weaken that of large particles, SO2, and NO2. Caused by the increase of flue gas flow rate, the nucleation process weakens, reducing the removal efficiency of all pollutants (particles, 45.2-28.3%; SO2, 27.5-14.5%; NO2, 21.5-15%). On the whole, the increase of the ideal supersaturation degree contributes to the synergistic removal of pollutants especially particles with smaller radius in the flue gas. The reduction of particles with aerodynamic diameter less than 1 μm is conductive to the synergistic removal of SO2 and NO2.
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Affiliation(s)
- Hao Zhang
- School of Energy and Power Engineering, Shandong University, Jinan, 250061, Shandong, China
| | - Yong Dong
- School of Energy and Power Engineering, Shandong University, Jinan, 250061, Shandong, China
| | - Yanhua Lai
- School of Energy and Power Engineering, Shandong University, Jinan, 250061, Shandong, China.
| | - Hao Zhang
- School of Energy and Power Engineering, Shandong University, Jinan, 250061, Shandong, China
| | - Xinbo Zhang
- School of Energy and Power Engineering, Shandong University, Jinan, 250061, Shandong, China
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Wang D, Chen Q, Zhang X, Gao C, Wang B, Huang X, Peng Y, Li J, Lu C, Crittenden J. Multipollutant Control (MPC) of Flue Gas from Stationary Sources Using SCR Technology: A Critical Review. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:2743-2766. [PMID: 33569951 DOI: 10.1021/acs.est.0c07326] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The emission of gaseous pollutants from the combustion of fossil fuels is believed to be one of the most serious environmental challenges in the 21st century. Given the increasing demands of multipollutant control (MPC) via adsorption or catalysis technologies, such as NOx, volatile organic compounds (VOCs), heavy metals (Hg etc.), and ammonia, and considering investment costs and site space, the use of existing equipment, especially the selective catalytic reduction (SCR) system to convert pollutants into harmless or readily adsorbed substances, is one of the most practical approaches. Consequently, many efforts have been directed at achieving the simultaneous elimination of multipollutants in a SCR convertor, and this method has been widely used to mitigate the stationary emission of NOx. However, the development of active, selective, stable, and multifunctional catalysts/adsorbents suitable for large-scale commercialization remains challenging. Herein, we summarize recent works on the applications of SCR in MPC, describing the approaches of (i) SCR + VOCs oxidation, (ii) SCR + heavy metal control, and (iii) SCR + NH3 reduction to reveal that the efficiency of simultaneous elimination depends on catalyst composition and flue gas parameters. Furthermore, the synergistic promotional/inhibitory effects between SCR and VOCs/ammonia/heavy metal oxidations are shown to be the key to the feasibility of the reactions.
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Affiliation(s)
- Dong Wang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, National Engineering Laboratory for Multi Flue Gas Pollution Control Technology and Equipment, School of Environment, Tsinghua University, Beijing 100084, China
- Brook Byers Institute for Sustainable Systems and School of Civil and Environmental Engineering, Georgia Institute of Technology, 828 West Peachtree Street, Atlanta, Georgia 30332, United States
| | - Qiuzhun Chen
- National Engineering Laboratory for Coal-Burning Pollutants Emission Reduction, School of Energy and Power Engineering, Shandong University, Jinan 250061, China
| | - Xiang Zhang
- National Engineering Laboratory for Coal-Burning Pollutants Emission Reduction, School of Energy and Power Engineering, Shandong University, Jinan 250061, China
| | - Chuan Gao
- National Engineering Laboratory for Coal-Burning Pollutants Emission Reduction, School of Energy and Power Engineering, Shandong University, Jinan 250061, China
| | - Bin Wang
- National Engineering Laboratory for Coal-Burning Pollutants Emission Reduction, School of Energy and Power Engineering, Shandong University, Jinan 250061, China
| | - Xu Huang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, National Engineering Laboratory for Multi Flue Gas Pollution Control Technology and Equipment, School of Environment, Tsinghua University, Beijing 100084, China
| | - Yue Peng
- State Key Joint Laboratory of Environment Simulation and Pollution Control, National Engineering Laboratory for Multi Flue Gas Pollution Control Technology and Equipment, School of Environment, Tsinghua University, Beijing 100084, China
| | - Junhua Li
- State Key Joint Laboratory of Environment Simulation and Pollution Control, National Engineering Laboratory for Multi Flue Gas Pollution Control Technology and Equipment, School of Environment, Tsinghua University, Beijing 100084, China
| | - Chunmei Lu
- National Engineering Laboratory for Coal-Burning Pollutants Emission Reduction, School of Energy and Power Engineering, Shandong University, Jinan 250061, China
| | - John Crittenden
- Brook Byers Institute for Sustainable Systems and School of Civil and Environmental Engineering, Georgia Institute of Technology, 828 West Peachtree Street, Atlanta, Georgia 30332, United States
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Wei J, Gu J, Guo J, Li W, Wang C, Zhang J. Simultaneous removal of nitrogen oxides and sulfur dioxide using ultrasonically atomized hydrogen peroxide. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:22351-22361. [PMID: 31154651 DOI: 10.1007/s11356-019-05531-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Accepted: 05/21/2019] [Indexed: 05/24/2023]
Abstract
A new method was developed for denitrification and desulfurization using hydrogen peroxide with the aid of an ultrasonic nebulizer to obtain high removal efficiency of NOx and SO2. Comparing with the atomizing nozzles having the aperture size of 0.01~0.02 mm, the droplets generated using the ultrasonic nebulizer show the smallest d50 value of 7.2 μm, with 72% possessing the size less than 10 μm. Based on the numerical simulation of the vaporization rate of droplets, it is indicated that the droplets with the size of 7.2 μm can be vaporized totally at very short residence time (0.11 s) under 130 °C. Effects of influence factors including the reaction temperature, the initial H2O2 concentration, pH value, and the flue gas flow rate were studied on the removal efficiencies of NO and SO2. Using the in-series double-oxidation subsystems with H2O2 concentration of 6 wt%, pH 5.0, and the reaction temperature of 130 °C, the removal efficiencies of SO2 and NO are respectively 100% and 89.3% at the short residence time of 1.8 s, and the removal efficiency of NO can be increased to 100% as the residence time is longer than 3.7 s. It is confirmed that the ultrasonically atomized H2O2 can indeed enhance the removal efficiencies of NO and SO2 at the optimal temperature, owing to the fast vaporization rate of fine droplets as well as the formation of more active radicals to be captured by NO and SO2 simultaneously. The results here provide a promising route to remove effectively the emissions of NO and SO2 simultaneously. Graphical abstract.
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Affiliation(s)
- Jiaqi Wei
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, People's Republic of China
| | - Junjie Gu
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, People's Republic of China
| | - Junheng Guo
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, People's Republic of China
| | - Wei Li
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, People's Republic of China
| | - Chenglong Wang
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, People's Republic of China
| | - Jinli Zhang
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, People's Republic of China.
- School of Chemistry and Chemical Engineering, Shihezi University, Shihezi, 832003, People's Republic of China.
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Wang J, Lu P, Su W, Xing Y, Li R, Li Y, Zhu T, Yue H, Cui Y. Study on the denitrification performance of Fe xLa yO z/activated coke for NH 3-SCR and the effect of CO escaped from activated coke at mid-high temperature on catalytic activity. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:20248-20263. [PMID: 31098908 DOI: 10.1007/s11356-019-05090-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2018] [Accepted: 04/04/2019] [Indexed: 06/09/2023]
Abstract
Currently, activated coke is widely used in the removal of multiple pollutants from industrial flue gas. In this paper, a series of novel FexLayOz/AC catalysts was prepared by the incipient wetness impregnation for NH3-SCR denitrification reaction. The introduction of Fe-La bimetal oxides significantly improved the denitrification performance of activated coke at mid-high temperature, and 4% Fe0.3La0.7O1.5/AC exhibited a superior NOx conversion efficiency of 90.1% at 400 °C. The catalysts were further characterized by BET, SEM, XRD, Raman, EPR, XPS, FTIR, NH3-TPD, H2-TPR, et al., whose results showed that the perovskite-type oxide of LaFeO3 and oxygen vacancies were produced on the catalysts' surfaces during roasting. Fe-La doping enhanced the amount of acid sites (mainly Lewis and other stronger acid sites) and the content of multifarious oxygen species, which were beneficial for NOx removal at mid-high temperature. Moreover, it was investigated that the effect of released CO from activated coke at mid-high temperature on the NOx removal through the lifetime test, in which it was found that a large amount of CO produced by pyrolysis of activated coke could promote the NOx removal, and long-term escaping of CO on the activated coke carrier did not have a significant negative impact on catalytic performance. The results of the TG-IR test showed that volatile matter is released from the activated coke while TG results showed that the weight loss rate of 4% Fe0.3La0.7O1.5/AC only was 0.0015~0.007%/min at 300-400 °C. Hence, 4% Fe0.3La0.7O1.5/AC had excellent thermal stability and denitrification performance to be continuously used at mid-high temperature. Finally, the mechanisms were proposed on the basis of experiments and characterization results.
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Affiliation(s)
- Jiaqing Wang
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing, 100083, People's Republic of China
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Pei Lu
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing, 100083, People's Republic of China
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Wei Su
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing, 100083, People's Republic of China.
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China.
| | - Yi Xing
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing, 100083, People's Republic of China.
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China.
| | - Rui Li
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing, 100083, People's Republic of China
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Yuran Li
- National Engineering Laboratory for Cleaner Hydrometallurgical Production Technology, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China
| | - Tingyu Zhu
- National Engineering Laboratory for Cleaner Hydrometallurgical Production Technology, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China
| | - Huifang Yue
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing, 100083, People's Republic of China
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Yongkang Cui
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing, 100083, People's Republic of China
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
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Yue H, Lu P, Su W, Xing Y, Li R, Wang J. Simultaneous removal of NO x and Hg 0 from simulated flue gas over Cu aCe bZr cO 3/r-Al 2O 3 catalysts at low temperatures: performance, characterization, and mechanism. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:13602-13618. [PMID: 30919195 DOI: 10.1007/s11356-019-04822-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Accepted: 03/07/2019] [Indexed: 06/09/2023]
Abstract
To optimize the simultaneous removal of NOx and Hg0, a series of CuaCebZrcO3/γ-Al2O3 catalysts prepared by the impregnation method were explored and their physical and chemical properties were analyzed by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) analysis, X-ray photoelectron spectroscopy (XPS), NH3-temperature-programmed desorption (NH3-TPD), H2-temperature-programmed reduction (H2-TPR), in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFT), and Fourier transform infrared spectroscopy (FT-IR). The results showed that 15% Cu1.4Ce0.55Zr0.25O3/γ-Al2O3 resulted in the highest conversion efficiency for the simultaneous removal of NOx (93%) and Hg0 (85%) at low temperatures (200 to 300 °C). Meanwhile, 15% Cu1.4Ce0.55Zr0.25O3/γ-Al2O3 showed good stability and resistance to SO2 and H2O, which is due to its low crystallinity, good textural performance, and strong redox ability. According to the TPD, TPR, and XPS results, the strong acidic character of 15% Cu1.4Ce0.55Zr0.25O3/γ-Al2O3 promoted the removal of NOx and Hg0. The synergistic effect between CuO and CeO2 in 15% Cu1.4Ce0.55Zr0.25O3/γ-Al2O3 can increase the mobility of chemically adsorbed oxygen and activates lattice oxygen, leading to an excellent performance. The DRIFT results showed that NH3, NH4+, nitrate, and nitrite participated in the selective catalytic reduction (SCR) reaction. On the basis of our experimental results, Hg0 and NOx removal mechanisms were proposed as Hg (ad) + O* → HgO (ad) and 2NH3/NH4+ (ad) + NO2/NO3- (ad) + NO→2N2 + 3H2O/2H+, respectively.
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Affiliation(s)
- Huifang Yue
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing, 100083, People's Republic of China
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Pei Lu
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing, 100083, People's Republic of China
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Wei Su
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing, 100083, People's Republic of China.
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China.
| | - Yi Xing
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing, 100083, People's Republic of China.
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China.
| | - Rui Li
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing, 100083, People's Republic of China
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Jiaqing Wang
- State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing, 100083, People's Republic of China
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
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