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Jiang B, Lin J, Hua H, Liu Y, Yu S, Sun Y. Simultaneous removal of naphthalene and NO x over V-Ce/Ti catalyst: Design of separated active sites for naphthalene degradation and SCR reaction. JOURNAL OF HAZARDOUS MATERIALS 2024; 474:134788. [PMID: 38850934 DOI: 10.1016/j.jhazmat.2024.134788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 05/30/2024] [Accepted: 05/31/2024] [Indexed: 06/10/2024]
Abstract
V-Ce/Ti catalysts were prepared for the removal of naphthalene and NOx in the flue gas. The adverse effects of NH3 and NO on the naphthalene degradation were weakened on V-Ce/Ti, resulting in a decrease of only 2.5 % in COx selectivity. The formation of high molecular weight byproducts was also reduced. Besides the acid sites on the catalysts, Ce introduced new Brønsted basic sites, which could also adsorb and degrade naphthalene into naphthol effectively. With the separated active sites for naphthalene degradation and NO removal, the reaction between NH3 and the intermediates during the naphthalene degradation was also inhibited, decreasing the formation and accumulation of phthalimide. The oxidation of the intermediates was promoted by active V5+ introduced by Ce, inhibiting the transformation of the intermediates to higher molecular weight byproducts. Nearly 100 % conversion of naphthalene and NO, as well as 40.1 % of the COx selectivity were obtained on V-Ce/Ti.
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Affiliation(s)
- Boqiong Jiang
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, China; Zhejiang Province Key Laboratory of Solid Waste Treatment and Recycling, Hangzhou 310012, China
| | - Jianxiang Lin
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, China
| | - Hao Hua
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, China
| | - Yue Liu
- Department of Environmental Engineering, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China
| | - Shaocai Yu
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, China; Zhejiang Province Key Laboratory of Solid Waste Treatment and Recycling, Hangzhou 310012, China
| | - Yuhai Sun
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, China; Zhejiang Province Key Laboratory of Solid Waste Treatment and Recycling, Hangzhou 310012, China.
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Wu Y, Xu Z, Liu S, Tang M, Lu S. The effect of air pollution control devices in coal-fired power plants on the removal of condensable and filterable particulate matter. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023:10.1007/s11356-023-27246-0. [PMID: 37148515 DOI: 10.1007/s11356-023-27246-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 04/23/2023] [Indexed: 05/08/2023]
Abstract
Total particulate matter (TPM), including condensable and filterable particulate matter (CPM and FPM), is one of the pollutants that need to be controlled in the coal combustion process. In this study, CPM and FPM were sampled from sixteen coal-fired power units and two coal-fired industrial units. The removal effects of air pollution control devices equipped in the units on the migration and emission of particles were investigated by analyzing samples from inlets and outlets of apparatus. The average removal efficiency of TPM by dry-type dust removal equipment, wet flue gas desulfurization devices, and wet-type precipitators reached 98.57 ± 0.90%, 44.89 ± 15.01%, and 28.45 ± 7.78%, respectively. The removal efficiency of dry-type dust removal equipment and wet-type precipitators to TPM is mainly determined by the purification effect of FPM and CPM, respectively, and both types of particles contribute to the removal efficiency of desulfurization systems to total TPM. The concentrations of CPM (12.01 ± 5.64 mg/Nm3) and FPM (1.95 ± 0.86 mg/Nm3) emitted from ultra-low emission units were the lowest, and CPM is the dominant particle, especially the higher proportion of organic components in CPM.
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Affiliation(s)
- Yujia Wu
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Zhenyao Xu
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Siqi Liu
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Minghui Tang
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Shengyong Lu
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China.
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Zhao L, Li Z, Qu L. Forecasting of Beijing PM 2.5 with a hybrid ARIMA model based on integrated AIC and improved GS fixed-order methods and seasonal decomposition. Heliyon 2022; 8:e12239. [PMID: 36590504 PMCID: PMC9800338 DOI: 10.1016/j.heliyon.2022.e12239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Revised: 11/17/2022] [Accepted: 12/01/2022] [Indexed: 12/13/2022] Open
Abstract
Accurate particulate matter 2.5 (PM2.5) prediction plays a crucial role in the accurate management of air pollution and prevention of respiratory diseases. However, PM2.5, as a nonlinear time series with great volatility, is difficult to achieve accurate prediction. In this paper, a hybrid autoregressive integrated moving average (ARIMA) model is proposed based on the Augmented Dickey-Fuller test (ADF root test) of annual PM2.5 data, thus demonstrating the necessity of first-order difference. The new method of using integrated akaike information criterion (AIC) and improved grid search (GS) methods is proposed to avoid the bias caused by using AIC alone to determine the order because the data are not exactly normally distributed. The comprehensive evaluation coefficient (CEC) is used to select the optimal parameter structure of the prediction model by considering multiple evaluation perspectives. The entropy value of the decomposed series is obtained by using range entropy A (RangeEn_A), and the series is reconstructed according to the entropy value, and finally the reconstructed series is predicted. We used Beijing PM2.5 data for validation and the results showed that the new hybrid ARIMA model improved values of RMSE 99.23%, MAE 99.20%, R2 118.61%, TIC 99.28%, NMAE 98.71%, NMSE 99.97%, OPC 43.13%, MOPC 98.43% and CEC 99.25% compared with the traditional ARIMA model. The results show that the method does greatly improve the prediction performance and provides a convincing tool for policy formulation and governance.
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Affiliation(s)
- Lingxiao Zhao
- College of Ocean and Civil Engineering, Dalian Ocean University, Dalian 116024, China
| | - Zhiyang Li
- College of Civil Engineering, Chongqing University, Chongqing 400044, China
| | - Leilei Qu
- College of Information Engineering, Dalian Ocean University, Dalian 116024, China
- Corresponding author.
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Catalytic Performance of One-Pot Synthesized Fe-MWW Layered Zeolites (MCM-22, MCM-36, and ITQ-2) in Selective Catalytic Reduction of Nitrogen Oxides with Ammonia. Molecules 2022; 27:molecules27092983. [PMID: 35566333 PMCID: PMC9104601 DOI: 10.3390/molecules27092983] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 04/28/2022] [Accepted: 05/01/2022] [Indexed: 01/17/2023] Open
Abstract
The application of layered zeolites of MWW topology in environmental catalysis has attracted growing attention in recent years; however, only a few studies have explored their performance in selective catalytic reduction with ammonia (NH3-SCR). Thus, our work describes, for the first time, the one-pot synthesis of Fe-modified NH3-SCR catalysts supported on MCM-22, MCM-36, and ITQ-2. The calculated chemical composition of the materials was Si/Al of 30 and 5 wt.% of Fe. The reported results indicated a correlation between the arrangement of MWW layers and the form of iron in the zeolitic structure. We have observed that one-pot synthesis resulted in high dispersion of Fe3+ sites, which significantly enhanced low-temperature activity and prevented N2O generation during the reaction. All of the investigated samples exhibited almost 100% NO conversion at 250 °C. The most satisfactory activity was exhibited by Fe-modified MCM-36, since 50% of NO reduction was obtained at 150 °C for this catalyst. This effect can be explained by the abundance of isolated Fe3+ species, which are active in low-temperature NH3-SCR. Additionally, SiO2 pillars present in MCM-36 provided an additional surface for the deposition of the active phase.
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Environmental Life Cycle Assessments of Chicken Manure Compost Using Tobacco Residue, Mushroom Bran, and Biochar as Additives. SUSTAINABILITY 2022. [DOI: 10.3390/su14094976] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
As an environmental management method, the (life cycle assessment) LCA method can be used to compare the differences between various waste treatment processes in order to provide an environmentally friendly and economically feasible method for waste management. This study focused on the reutilization of typical organic waste to produce organic fertilizer in southwest China and used the life cycle assessment method to evaluate three aerobic chicken manure composting scenarios modified with three additives (biochar, mushroom bran, and tobacco residue) from an environmental and economic perspective. The results show that the total environmental loads of the optimized treatments using mushroom bran and biochar mixed with mushroom bran as additives were reduced by 30.0% and 35.1%, respectively, compared to the control treatment (viz. chicken manure composted with tobacco residue). Compared to the control treatment, the optimized composting treatment modified by mushroom bran with and without biochar improved the profit by 23.9% and 35.4%, respectively. This work reflected that the combined composting mode of chicken manure, tobacco residue, mushroom bran, and biochar is an environmentally friendly and economically feasible composting process, which is more suitable for the resource utilization of the typical organic waste in southwest China.
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Ai X, Li L, Zhou X, Zhang Z. A monitoring method for sulfate based on ultraviolet absorption spectroscopy dedicated to SO3 monitoring in coal-fired power plants. Chem Phys Lett 2021. [DOI: 10.1016/j.cplett.2021.138935] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Wu X, Liu W, Gao H, Alfaro D, Sun S, Lei R, Jia T, Zheng M. Coordinated effects of air pollution control devices on PAH emissions in coal-fired power plants and industrial boilers. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 756:144063. [PMID: 33288269 DOI: 10.1016/j.scitotenv.2020.144063] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 11/21/2020] [Accepted: 11/22/2020] [Indexed: 06/12/2023]
Abstract
Coal-fired power plants are important sources of polycyclic aromatic hydrocarbon (PAH) emissions in the world. The effects of various air pollution control devices (APCDs) on PAH emissions were investigated by analyzing samples from inlets and outlets of APCDs in six coal-fired power plants (A-F) and two coal-fired industrial boilers (G and H). The APCDs were electrostatic precipitators (ESPs), wet flue gas desulfurization systems (WFGDs), and wet ESPs (WESPs). The PAH congener patterns for the coal-fired plants were similar. Gas-phase PAHs were dominant in flue gases, and the most abundant PAH was naphthalene. Three- and four-ring PAHs were dominant in fly ash. Positive correlations were found between the PAH and total organic carbon contents of fly ash (R2 0.87) and slag (R2 0.92). Plants D-F, equipped with low-low-temperature ESPs (LLT-ESPs) and WESPs discharged the lowest PAHs. Circulating water was an important source of PAHs in the desulfurization except in plant A, which used desalinated seawater rather than circulating water in the desulfurization process. WESPs decreased PAH concentrations by an average of 20.67%, which can be spread to other plants to reduce PAHs.
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Affiliation(s)
- Xiaolin Wu
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wenbin Liu
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Hangzhou Institute for Advanced Study, UCAS, Hangzhou 310024, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Hanfei Gao
- Key Laboratory of Bio-inspired Materials and Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - David Alfaro
- Department of Environmental Sciences, University of California, Riverside, CA 92521, United States
| | - Shurui Sun
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Rongrong Lei
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tianqi Jia
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Minghui Zheng
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Hangzhou Institute for Advanced Study, UCAS, Hangzhou 310024, China; University of Chinese Academy of Sciences, Beijing 100049, China
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Behaviors of Chromium in Coal-Fired Power Plants and Associated Atmospheric Emissions in Guizhou, Southwest China. ATMOSPHERE 2020. [DOI: 10.3390/atmos11090951] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Coal burning is a main concern for a range of atmospheric pollutants, including the environmentally sensitive element chromium (Cr). Cr migrates to the environment through stack emissions and can leach out from solid coal-burning byproducts, thereby causing adverse effects on the ecosystem. In this study, atmospheric emissions of Cr from six coal-fired power plants (CFPPs), as well as the distribution of Cr inside these CFPPs in Guizhou Province, Southwest China, were investigated. Among the six CFPPs, one was a circulating fluidized bed boiler and the others were pulverized coal boilers. The results showed that Cr in the feed fuel of these CFPPs ranged from 39.5 to 101.5 mg·kg−1 (average: 68.0 ± 24.8 mg·kg−1) and was approximately four times higher than the national and global average. Cr in the feed fuel correlated significantly with the ash yield, demonstrating that Cr in coal is closely associated with ash-forming minerals. After the coal combustion and the treatment by different air pollution control devices, most Cr (>92%) in the installation was retained in the captured fly ash and bottom ash, with less as gypsum (0.69–7.94%); eventually, only 0.01–0.03% of Cr was emitted into the atmosphere with a concentration of 1.4–2.2 μg·Nm−3. The atmospheric emission factors of Cr for these utility boilers were as low as 14.86 ± 3.62 mg Cr·t−1 coal, 7.72 ± 2.53 μg Cr (kW·h)−1, and 0.70 ± 0.19 g Cr·TJ−1, respectively. About 981 kg·y−1 of Cr was discharged into the atmosphere from Guizhuo’s CFPPs in 2017, much lower than previous reported values. Most of the Cr in the CFPPs ended up in solid combustion products, identifying the need for the careful disposal of high-Cr-containing ashes (up to 500 mg·kg−1) to prevent possible mobilization into the environment.
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Numerical Investigation of SCR Mixer Design Optimization for Improved Performance. Processes (Basel) 2019. [DOI: 10.3390/pr7030168] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The continuous increase in the number of stringent exhaust emission legislations of marine Diesel engines had led to a decrease in NOx emissions at the required level. Selective catalyst reduction (SCR) is the most prominent and mature technology used to reduce NOx emissions. However, to obtain maximum NOx removal with minimum ammonia slip remains a challenge. Therefore, new mixers are designed in order to obtain the maximum SCR efficiency. This paper reports performance parameters such as uniformity of velocity, ammonia uniformity distribution, and temperature distribution. Also, a numerical model is developed to investigate the interaction of urea droplet with exhaust gas and its effects by using line (LM) and swirl (SM) type mixers alone and in combination (LSM). The urea droplet residence time and its interaction in straight pipe are also investigated. Model calculations proved the improvement in velocity uniformity, distribution of ammonia uniformity, and temperature distribution for LSM. Prominent enhancement in the evaporation rate was also achieved by using LSM, which may be due to the breaking of urea droplets into droplets of smaller diameter. Therefore, the SCR system accomplished higher urea conversion efficiency by using LSM. Lastly, the ISO 8178 standard engine test cycle E3 was used to verify the simulation results. It has been observed that the average weighted value of NOx emission obtained at SCR outlet using LSM was 2.44 g/kWh, which strongly meets International Maritime Organization (IMO) Tier III NOx (3.4 g/kWh) emission regulations.
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