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Xia H, Tang J, Aljerf L, Wang T, Gao B, Xu Q, Wang Q, Ukaogo P. Assessment of PCDD/Fs formation and emission characteristics at a municipal solid waste incinerator for one year. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 883:163705. [PMID: 37105483 DOI: 10.1016/j.scitotenv.2023.163705] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 03/25/2023] [Accepted: 04/20/2023] [Indexed: 05/03/2023]
Abstract
Municipal solid waste incineration (MSWI) has become a predominant emission source of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs). Research focusing on the impact of operating conditions, environmental changes, and operating time on the generation and emissions of PCDD/Fs has not been resolved. To this end, this study tracked and investigated the PCDD/Fs and 17 congener emissions of a typical grate incinerator (800 t/d) continuously for one year. Results showed that the PCDD/Fs concentration at the boiler outlet, stack inlet, and bag filter, including normal and abnormal operation conditions, ranges from 2.11E-02-41.86 ng I-TEQ/Nm3, 7.00E-04-6.76 ng I-TEQ/Nm3, and 1.12-2.90E+03 ng I-TEQ/Nm3, respectively. The 2,3,4,7,8-P5CDF has the highest contribution in all samples, in which a proportion of TEQ ranged from 30 % to 77.73 %. Moreover, by applying the correlation analysis between PCDD/Fs and operating parameters, the emission characteristic is mainly affected by incinerators and boilers during the normal period, and it is affected by the whole MSWI process under abnormal conditions. In addition, the PCDD/Fs emission from the MSWI plant gradually increases from spring to winter. This study is beneficial for supporting the control of PCDD/Fs emission reduction and assisting the operators to optimize the relevant operating parameters of the MSWI plant to achieve a stable and up-to-substandard emissions during the operation period.
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Affiliation(s)
- Heng Xia
- Faculty of Information Technology, Beijing University of Technology, Beijing 100124, China; Beijing Laboratory of Smart Environmental Protection, Beijing 100124, China
| | - Jian Tang
- Faculty of Information Technology, Beijing University of Technology, Beijing 100124, China; Beijing Laboratory of Smart Environmental Protection, Beijing 100124, China.
| | - Loai Aljerf
- Key Laboratory of Organic Industries, Department of Chemistry, Faculty of Sciences, Damascus University, Damascus, Syrian Arab Republic.
| | - Tianzheng Wang
- Faculty of Information Technology, Beijing University of Technology, Beijing 100124, China; Beijing Laboratory of Smart Environmental Protection, Beijing 100124, China
| | - Bingyin Gao
- Beijing GaoAnTun Waste to Energy CO., Ltd, China
| | - Qindong Xu
- Jiangsu WEIPU Testing Technology Co., Ltd, China
| | - Qiang Wang
- Jiangsu WEIPU Testing Technology Co., Ltd, China
| | - Prince Ukaogo
- Analytical/Environmental Units, Department of Pure and Industrial Chemistry, Abia State University, Uturu, Nigeria
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Zhan MX, Liu YW, Ye WW, Chen T, Jiao WT. Modification of activated carbon using urea to enhance the adsorption of dioxins. ENVIRONMENTAL RESEARCH 2022; 204:112035. [PMID: 34509483 DOI: 10.1016/j.envres.2021.112035] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 09/07/2021] [Accepted: 09/07/2021] [Indexed: 06/13/2023]
Abstract
Activated carbon is commonly used to remove dioxins from flue gas via adsorption. Improving the targeted adsorption capacity of activated carbon for dioxins can reduce the consumption of adsorbents and help achieve emission standards for target pollutants. Here, commercial coal-based activated carbon was used as a raw material and modified by urea impregnation along with treatment at high temperature under a nitrogen atmosphere. It was found that modification with urea effectively improved the pore structure of activated carbon while incorporating a certain amount of nitrogen. The best modification effect was achieved at a modification temperature of 600 °C, an impregnation ratio of urea to activated carbon of 1:1, and with high-temperature treatment for 2 h. The mesopore volume of the modified activated carbon (AC600) reached 0.38 cm3/g, accounting for 57.58% of the total pore volume. With an impregnation ratio of urea to activated carbon of 1:1, high-temperature treatment for 2 h, and a modification temperature of 800 °C, a certain amount of nitrogen was introduced into the carbon rings to form a modified activated carbon (AC800) rich in pyridine and pyrrole groups (atomic percentage = 4.84%). The activated carbon modified by urea and the unmodified activated carbon were subsequently selected for dioxin adsorption experiments using a dioxin generation and adsorption system. AC600 showed the highest adsorption efficiency for dioxins, reaching 97.65%, based on toxicity equivalents. Although AC800 has poor pore properties, it has more pyridine and pyrrole groups than AC600. Consequently, the efficiency of AC800 at adsorbing low-concentration dioxins reached 85.24% based on toxicity equivalents. Overall, this study describes two mechanisms for effectively modifying activated carbon with urea based on (1) optimizing the pore structure of activated carbon and (2) incorporating nitrogen.
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Affiliation(s)
- Ming-Xiu Zhan
- College of Metrology and Measurement Engineering, China Jiliang University, Hangzhou, 310018, Zhejiang Province, China; Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, China 18 Shuangqing Road, Haidian District, Beijing, 100085, China
| | - Yu-Wei Liu
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, China; Shanghai SUS Environmental Co. Ltd., 9 Songqiu Road, Qingpu District, Shanghai, 201703, China
| | - Wen-Wen Ye
- College of Metrology and Measurement Engineering, China Jiliang University, Hangzhou, 310018, Zhejiang Province, China
| | - Tong Chen
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, China
| | - Wen-Tao Jiao
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, China 18 Shuangqing Road, Haidian District, Beijing, 100085, China.
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Lv ZY, Yu Y, Ren M, Dang T, Wu S, Zhou H, Gao L, Yue J, Zhang H, Jiping C. Spraying polyacrylamide solution to improve the removal of particle-phase dioxins by bag filter in a full-scale municipal solid waste incineration system. CHEMOSPHERE 2021; 285:131392. [PMID: 34242988 DOI: 10.1016/j.chemosphere.2021.131392] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 06/27/2021] [Accepted: 06/28/2021] [Indexed: 06/13/2023]
Abstract
A field experiment was conducted in a modern municipal solid waste (MSW) incineration power plant to explore the feasibility of using chemical agglomeration agent anionic polyacrylamide (PAM) to reduce the atmospheric emission of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). Spraying PAM solution into the cooling tower caused an obvious decrease in the volume fraction of ultrafine and fine particles with diameter of 0.3-30 μm in BF fly ash, and a significant reduction in dust content in stack gas. The increased agglomeration of particles promoted the removal of particle-phase PCDD/Fs by BF, and thus resulted in a lower atmospheric emission of PCDD/Fs. The calculated removal efficiency of PCDD/Fs by BF was almost positively proportional to the concentration of PAM solution, while inversely proportional to the average content of dusk in stack gas. Compared with the control treatment, the spraying of 0.1 g/L PAM solution enhanced the removal efficiency of total tetra-to octa-CDD/Fs (∑PCDD/Fs) from 93.8% to 97.8% by BF, and resulted in a decrease of 47.0% in the concentration of international toxicity equivalent (I-TEQ) in stack gas. During the experiment of 2 d, the spraying of PAM solution did not induce a significant change in the differential pressure of BF, and did not essentially affect the partitioning behaviors of PCDD/F homologues between flue gas and BF fly ash. In view of technical safety and low cost, PAM application is recommended for reducing the atmospheric emission of PCDD/Fs from MSW incineration system.
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Affiliation(s)
- Zhenzhong Yang Lv
- College of Environmental Sciences and Engineering, Dalian Maritime University, Dalian, 116026, China; CAS Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China
| | - Ying Yu
- College of Environmental Sciences and Engineering, Dalian Maritime University, Dalian, 116026, China.
| | - Meihui Ren
- CAS Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China
| | - Tong Dang
- Shanghai Environment Group Co, Ltd., Shanghai, 200336, China
| | - Shunyang Wu
- Shanghai Environment Group Co, Ltd., Shanghai, 200336, China
| | - Hongquan Zhou
- Shanghai Environmental Sanitation Engineering Design Institute Co., Ltd., Shanghai, 200232, China
| | - Lei Gao
- Shanghai Environment Group Co, Ltd., Shanghai, 200336, China
| | - Junchao Yue
- Shanghai Environment Group Co, Ltd., Shanghai, 200336, China
| | - Haijun Zhang
- CAS Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China.
| | - Chen Jiping
- CAS Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China
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Hsu YC, Chang SH, Chang MB. Emissions of PAHs, PCDD/Fs, dl-PCBs, chlorophenols and chlorobenzenes from municipal waste incinerator cofiring industrial waste. CHEMOSPHERE 2021; 280:130645. [PMID: 33933998 DOI: 10.1016/j.chemosphere.2021.130645] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 04/18/2021] [Accepted: 04/22/2021] [Indexed: 06/12/2023]
Abstract
Concentrations and distributions of PAHs and chlorinated aromatic compounds including PCDD/Fs, dl-PCBs, chlorophenols (CPs), and chlorobenzenes (CBz) in the municipal waste incinerator are investigated to characterize their formation and emission via intensive stack sampling. In addition, the toxicity of fly ash contribution by PCDD/Fs and dl-PCBs is evaluated in this study. The results reveal that concentrations of PCDD/Fs and dl-PCBs in flue gas are significantly lower than those of CPs, CBz, and PAHs. Additionally, the removal efficiencies of PAHs and chlorinated aromatic compounds achieved with existing air pollution control devices are evaluated, indicating that the removal efficiencies achieved with activated carbon injection + baghouse (95-99%) are higher than those with semi-dry scrubber (SDS). Besides, PCDD/Fs and PCBs TEQ concentrations in SDS and BH ashes are within 1.61-2.66 WHO-TEQ/g and 0.09-0.19 WHO-TEQ/g, respectively. Furthermore, the calculated mass flow rates suggest that the input rate of PCDD/Fs and dl-PCBs of SDS are 60.24 mg/h and 59.74 mg/h, respectively. The mass flow rates of PCDD/Fs and dl-PCBs after SDS in flue gas are 32.47 mg/h and 49.73 mg/h, respectively. However, the discharge rates of PCDD/Fs and dl-PCBs from SDS are 120.60 mg/h and 27.05 mg/h, respectively, indicating that PCDD/Fs are significantly formed within the SDS. PCDD/Fs formation is attributed to the operating temperature of SDS (240 ± 11.5 °C), which is within the temperature window for de novo synthesis. Thus, operating parameters of the APCDs should be optimized to reduce the formation of PAHs and chlorinated aromatic pollutants from MWI.
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Affiliation(s)
- Yen-Chen Hsu
- Graduate Institute of Environmental Engineering, National Central University, Chungli, Taiwan, 320
| | - Shu-Hao Chang
- Graduate Institute of Environmental Engineering, National Central University, Chungli, Taiwan, 320
| | - Moo Been Chang
- Graduate Institute of Environmental Engineering, National Central University, Chungli, Taiwan, 320.
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Huang Y, Lu JW, Xie Y, Hong C, Shi L, Hai J. Process tracing of PCDD/Fs from economizer to APCDs during solid waste incineration: Re-formation and transformation mechanisms. WASTE MANAGEMENT (NEW YORK, N.Y.) 2021; 120:839-847. [PMID: 33268046 DOI: 10.1016/j.wasman.2020.11.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 08/31/2020] [Accepted: 11/11/2020] [Indexed: 06/12/2023]
Abstract
The emission of PCDD/Fs is a crucial factor for the aggravation of the Not-In-My-Back-Yard (NIMBY) syndrome, especially for the incineration plants that fail to meet the emission standard. It is well known that physicochemical processes in the boiler can notably affect the discharge of dioxins, especially under transient, non-steady conditions. However, few studies paid attention to the important operational parameters that influence PCDD/Fs formation and transformation in the boiler when an incinerator is in its daily steady operation. In this study, 36 samples were analyzed to achieve process tracing of PCDD/Fs. The concentration, congener profile and vapor/solid partitions of PCDD/Fs from the economizer to air pollution control devices (APCDs) under two typical steady conditions were investigated. Results indicated that increasing air supply aggravated the formation of PCDD/Fs, disturbed the vapor/solid partitions, and triggered a substandard emission. Quantitative structure-activity relationship (QSAR) modeling was firstly performed for the formation mechanism and orbital energy factors were identified as dominating factors. Besides, the removal rates of PCDD/Fs significantly correlated with the saturated vapor pressure and proportions of different isomers. This study is beneficial for operators to optimize relevant operational parameters of the incineration plants so as to get rid of substandard problems.
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Affiliation(s)
- Yuanqing Huang
- South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510655, China
| | - Jia-Wei Lu
- South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510655, China; Guangdong Province Engineering Laboratory for Solid Waste Technology and Equipment, Guangzhou 510330, China.
| | - Yingshi Xie
- South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510655, China; Guangdong Province Engineering Laboratory for Solid Waste Technology and Equipment, Guangzhou 510330, China
| | - Chengyang Hong
- South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510655, China
| | - Lizheng Shi
- South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510655, China
| | - Jing Hai
- South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510655, China; Guangdong Province Engineering Laboratory for Solid Waste Technology and Equipment, Guangzhou 510330, China.
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Li H, Liu W, Lu A, Li C, Die Q, Lei R, Wu X. PCDD/Fs emissions from secondary copper production synergistically controlled by fabric filters and desulfurization. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 270:116065. [PMID: 33221088 DOI: 10.1016/j.envpol.2020.116065] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 11/08/2020] [Accepted: 11/09/2020] [Indexed: 06/11/2023]
Abstract
The effects of fabric filters and desulfurization systems during secondary copper smelting on polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) concentrations, emission coefficients, and profiles were studied in an oxygen-rich smelting furnace and an anode furnace. In the anode furnace, the toxic equivalent (TEQ) concentration ranges were 0.106-1.04 ng World Health Organization (WHO)-TEQ/m3 at the fabric filters inlet and 0.027-0.17 ng WHO-TEQ/m3 at the outlet. For the oxygen-rich smelting furnace, the TEQ concentration ranges were 1.21-1.93 and 0.010-0.019 ng WHO-TEQ/m3 at the desulfurization system inlet and outlet, respectively. The TEQs in the outlet stack gases of the desulfurization system from the anode furnace were 0.0041-0.016 ng WHO-TEQ/m3. It is likely that PCDD/Fs that were taken away from the stack gases were adsorbed by the fly ash and gypsum. Solid residues were the dominant release routes for PCDD/Fs. PCDD/Fs congener and homologue profiles of stack gases from different smelting stages were similar. The contributions of more chlorinated homologues from the anode furnace decreased observably after the stack gases passed through the fabric filters. However, the desulfurization process did not greatly change the PCDD/Fs homologue profiles. Overall, both the fabric filters and desulfurization systems showed excellent removal efficiencies for PCDD/Fs in the stack gases, which reduced the TEQ emissions to well below the 0.5 ng WHO-TEQ/m3 to achieve standard discharge.
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Affiliation(s)
- Haifeng Li
- Beijing Municipal Key Laboratory of Agriculture Environment Monitoring, Beijing Research Center for Agricultural Standards and Testing, Beijing, 100097, China; Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, 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.
| | - Anxiang Lu
- Beijing Municipal Key Laboratory of Agriculture Environment Monitoring, Beijing Research Center for Agricultural Standards and Testing, Beijing, 100097, China
| | - Cheng Li
- Beijing Municipal Key Laboratory of Agriculture Environment Monitoring, Beijing Research Center for Agricultural Standards and Testing, Beijing, 100097, China
| | - Qingqi Die
- Beijing Municipal Key Laboratory of Agriculture Environment Monitoring, Beijing Research Center for Agricultural Standards and Testing, Beijing, 100097, 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
| | - Xiaolin Wu
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
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Lin X, Ma Y, Chen Z, Li X, Lu S, Yan J. Effect of different air pollution control devices on the gas/solid-phase distribution of PCDD/F in a full-scale municipal solid waste incinerator. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 265:114888. [PMID: 32554086 DOI: 10.1016/j.envpol.2020.114888] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 05/26/2020] [Accepted: 05/26/2020] [Indexed: 06/11/2023]
Abstract
The emission of polychlorinated dibenzo-p-dioxins and -furans (PCDD/F) from full-scale municipal solid waste incinerators (MSWI) is harmful to human and environmental health. This study analyzes the effect of different units of an air pollution control devices (APCDs), i.e. the semi-dry scrubber, fabric filter (FF), selective catalytic reduction (SCR), and wet scrubber (WS), on the removal characteristics and gas- and solid-phase distributions of PCDD/F in MSWI flue gas. APCDs reduce PCDD/F concentrations from 24.9 ng Nm-3 to 0.979 ng Nm-3 (2.16 ng I-TEQ Nm-3 to 0.0607 ng I-TEQ Nm-3), with a total removal efficiency (RE) of 96.1% (97.2% I-TEQ). Specifically, APCDs remove more than 95% of both gas- and solid-phase PCDD/F. The FF coupled with active carbon injection (FF + ACI) substantially reduces both gas- and solid-phase PCDD/F concentrations with an RE of 97.2% (98.7% I-TEQ). Additionally, FF + ACI exhibits a better RE of PCDF (98.9%) than PCDD (94.6%) and leads to PCDD congeners dominating the gas-phase. Both desorption and destruction of PCDD/F occur in the SCR, which favors removal of gas-phase PCDD/F but increases solid-phase PCDD/F. Therefore, SCR only decreases PCDD/F with a low RE of 27.6% (16.9% I-TEQ). However, SCR reduces NOx with a high RE of 82.3%, which could inhibit the RE of PCDD/F because of their different reaction mechanisms. WS increases PCDD/F in both the gas and solid-phase by 1.95 times (2.57 times for I-TEQ) due to the memory effect, which typically increases the total mass concentration of PCDD/F and the proportions of lower-chlorinated gas-phase PCDD/F. Migration of gas- and solid-phase PCDD/F are also analyzed according to temperature. The results of this study can contribute to the optimized design of industrial APCDs for controlling PCDD/F emissions from MSWI.
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Affiliation(s)
- Xiaoqing Lin
- State Key Laboratory for Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Yunfeng Ma
- State Key Laboratory for Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Zhiliang Chen
- Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, TN, 37215, USA
| | - Xiaodong Li
- State Key Laboratory for Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China.
| | - Shengyong Lu
- State Key Laboratory for Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Jianhua Yan
- State Key Laboratory for Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China
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Ren M, Lv ZY, Xu L, Lu Q, Zhang X, Yu Y, Fan Y, Gao Y, Chen J, Zhang H. Partitioning and removal behaviors of PCDD/Fs, PCBs and PCNs in a modern municipal solid waste incineration system. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 735:139134. [PMID: 32473439 DOI: 10.1016/j.scitotenv.2020.139134] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 04/28/2020] [Accepted: 04/29/2020] [Indexed: 06/11/2023]
Abstract
An extensive evaluation on a modern full-scale municipal solid waste incineration system was conducted for characterizing the distribution of highly toxic chlorinated aromatics, polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs) and polychlorinated naphthalenes (PCNs), and their corresponding mass fluxes in post combustion zone. It was found that the flue gas/fly ash partitioning behaviors of chlorinated aromatics could be essentially described by their octanol-air partition coefficients (KOA) and strongly affected by the flue gas temperature. Above 93% of chlorinated aromatics formed in boiler section was partitioned into the flue gas and transported into the subsequent flue gas cleaning system, in which above 92% of Cl3-8DDs, Cl3-7DFs, Cl5-10Bs and Cl4-8Ns in flue gas was removed by the discharge of fly ash. The results of mass flux calculation indicated that the memory effect in flue gas cleaning system remarkably elevated the emission levels of chlorinated aromatics, especially the less chlorinated ones. The memory effect should mainly result from the direct chlorination mechanism mediated by the deposited particles. In addition, activated carbon injection could cause an obvious increase in PCBs emission. The obtained results provided some important implications for further reducing the emission of highly toxic chlorinated aromatics.
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Affiliation(s)
- Meihui Ren
- CAS Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhenzhong Yang Lv
- CAS Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China; College of Environmental Science and Engineering, Dalian Maritime University, Dalian 116026, China
| | - Lin Xu
- Changshu PUFA No.2 Thermoelectric Energy Co., Ltd., Changshu 215513, China.
| | - Qiqi Lu
- Changshu PUFA No.2 Thermoelectric Energy Co., Ltd., Changshu 215513, China
| | - Xuefeng Zhang
- Changshu PUFA No.2 Thermoelectric Energy Co., Ltd., Changshu 215513, China
| | - Ying Yu
- College of Environmental Science and Engineering, Dalian Maritime University, Dalian 116026, China
| | - Yun Fan
- CAS Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China
| | - Yuan Gao
- CAS Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China
| | - Jiping Chen
- CAS Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China
| | - Haijun Zhang
- CAS Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China.
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Trinh MM, Kuo CH, Chang MB. Characterization of PCDD/Fs and dl-PCBs emission from combustion of PCB-containing oil in a fluidized-bed incinerator. CHEMOSPHERE 2019; 225:35-42. [PMID: 30856473 DOI: 10.1016/j.chemosphere.2019.03.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 02/19/2019] [Accepted: 03/03/2019] [Indexed: 06/09/2023]
Abstract
Emissions of PCDD/Fs and dl-PCBs from the combustion of PCB-containing oil in a hazardous waste incinerator are characterized. Flue gas samples are simultaneously taken at three points, including the outlet of ultrasonic wet scrubber, the outlet of heat exchanger and stack. In addition, solid matter samples including incinerator bottom ash, wet scrubber sludge, heat exchanger ash and baghouse ash are also collected. The results indicate that TEQ concentration (PCDD/Fs + dl-PCBs) measured in stack from the combustion of PCB-containing oil is 0.51 ng WHO-TEQ/Nm3. For the solid matter, PCDD/F and dl-PCB concentrations of baghouse ash and wet scrubber sludge are significantly higher than those measured in bottom and heat exchanger ashes. The total removal efficiencies of PCDD/Fs + dl-PCBs achieved with bag filtration (BF) + activated carbon injection (ACI) reaches 65.0%. The emission factors of PCDD/Fs and dl-PCBs from incinerating PCB-containing oil are 1.05 and 0.08 ng WHO-TEQ/L, respectively. The overall PCDD/Fs and dl-PCBs destruction efficiencies achieved with fluidized-bed incinerator reach 99.87% and 99.9998%, respectively, which demonstrates that incineration is an effective engineering practice for treating PCB-containing oil. Moreover, this is the first study suggesting the ratios of PCB-114/(PCB-126+ PCB-114) and PCB-157/(PCB-169+ PCB-157) as indicators to distinguish the emission source of dl-PCB from combustion process and technical mixture evaporation in diagnostic ratio analysis.
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Affiliation(s)
- Minh Man Trinh
- Graduate Institute of Environmental Engineering, National Central University, Chungli, 320, Taiwan.
| | - Chun Hsin Kuo
- Graduate Institute of Environmental Engineering, National Central University, Chungli, 320, Taiwan.
| | - Moo Been Chang
- Graduate Institute of Environmental Engineering, National Central University, Chungli, 320, Taiwan.
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Liu Y, Diao X, Tao F, Yang C, Wang H, Takaoka M, Sun Y. Insight into the low-temperature decomposition of Aroclor 1254 over activated carbon-supported bimetallic catalysts obtained with XANES and DFT calculations. JOURNAL OF HAZARDOUS MATERIALS 2019; 366:538-544. [PMID: 30572293 DOI: 10.1016/j.jhazmat.2018.12.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 12/03/2018] [Accepted: 12/06/2018] [Indexed: 06/09/2023]
Abstract
Novel bimetallic catalysts supported on activated carbon (AC) with high metal loadings were synthesized by carbonizing an ion-exchange resin. AC-supported Ni-Cu (Ni-Cu/C) and Ni-Zn (Ni-Zn/C) bimetallic catalysts with different Ni:Cu(Zn) ratios were used to decompose Aroclor 1254, which is a commonly used commercial mixture of polychlorinated biphenyls. Characterization with scanning electron microscopy and energydispersive X-ray spectroscopy showed that the metals were uniformly distributed on the surfaces and inside the catalysts. After 30 min reaction over the Ni-Cu/C catalyst at a low temperature of 250 °C, the efficiencies of Hexa-CBs decomposition present in Aroclor 1254 exceeded 97%, which were higher than those achieved over Ni-Zn/C. These efficiencies increased with Cu content in Ni-Cu/C, and decreased with the amount of Zn in Ni-Zn/C. X-ray photoelectron spectra and X-ray absorption near-edge structure spectra of Ni-Cu/C and Ni-Zn/C before and after the reaction indicated that Ni and Cu were oxidized during the reaction. However, Zn showed no significant change, suggesting that Ni and Cu are the active components to promote reaction with Aroclor 1254, whereas Zn is only a spectator. The efficiencies of Aroclor 1254 decomposition over bimetallic catalysts were greater than those over monometallic catalysts, which was confirmed by density functional theory calculations.
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Affiliation(s)
- Yawen Liu
- School of Physics, Beihang University, Beijing, 100191, China; Beijing Key Laboratory of Bio-inspired Energy Materials and Devices, School of Space and Environment, Beihang University, Beijing, 100191, China
| | - Xungang Diao
- School of Energy and Power Engineering, Beihang University, Beijing, 100191, China
| | - Fei Tao
- Beijing Key Laboratory of Bio-inspired Energy Materials and Devices, School of Space and Environment, Beihang University, Beijing, 100191, China
| | - Chengwu Yang
- Beijing Key Laboratory of Bio-inspired Energy Materials and Devices, School of Space and Environment, Beihang University, Beijing, 100191, China
| | - Haining Wang
- Beijing Key Laboratory of Bio-inspired Energy Materials and Devices, School of Space and Environment, Beihang University, Beijing, 100191, China
| | - Masaki Takaoka
- Graduate School of Global Environmental studies, Kyoto University, Kyoto, 615-8540, Japan
| | - Yifei Sun
- Beijing Key Laboratory of Bio-inspired Energy Materials and Devices, School of Space and Environment, Beihang University, Beijing, 100191, China.
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11
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Xu J, Liu Y, Tao F, Sun Y. Kinetics and reaction pathway of Aroclor 1254 removal by novel bimetallic catalysts supported on activated carbon. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 651:749-755. [PMID: 30245430 DOI: 10.1016/j.scitotenv.2018.09.200] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 09/09/2018] [Accepted: 09/16/2018] [Indexed: 06/08/2023]
Abstract
Bimetallic catalysts supported on activated carbon (AC) with high metal loadings were prepared by an ion-exchange method. AC-supported Ni-Cu, Ni-Zn and Ni-Pd bimetallic catalysts were used to decompose Aroclor 1254, which is one of the most commonly used commercial mix of polychlorinated biphenyls. Characterization by scanning electron microscopy and energy-dispersive X-ray analysis showed that the metals were uniformly distributed on the surfaces and inside the catalysts. The efficiencies of Aroclor 1254 decomposition were measured at different reaction temperatures and times. With increasing temperature, the catalytic activities increased and the activation energies of the reactions decreased, resulting in higher decomposition efficiencies. At 300 °C in a nitrogen atmosphere, Aroclor 1254 decomposition efficiencies of 99.3%, 99.4% and 99.5% were achieved for reactions with Ni-Cu/C, Ni-Zn/C and Ni-Pd/C, respectively. The kinetics and pathway of the decomposition reaction were discussed, and we concluded that the reactivity of the chlorine atoms located on the benzene rings followed the order para-position > meta-position > ortho-position. The PCBs were dechlorinated stepwise to form the final biphenyl product. The design concept and synthetic strategy developed in this study are of great significance in the disposal of chlorinated organic compounds, for use with the existing adsorption technology of AC.
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Affiliation(s)
- Jiani Xu
- Beijing Key Laboratory of Bio-inspired Energy Materials and Devices, School of Space and Environment, Beihang University, Beijing 100191, China; School of Chemistry, Beihang University, Beijing 100191, China
| | - Yawen Liu
- Beijing Key Laboratory of Bio-inspired Energy Materials and Devices, School of Space and Environment, Beihang University, Beijing 100191, China; School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191, China
| | - Fei Tao
- Beijing Key Laboratory of Bio-inspired Energy Materials and Devices, School of Space and Environment, Beihang University, Beijing 100191, China
| | - Yifei Sun
- Beijing Key Laboratory of Bio-inspired Energy Materials and Devices, School of Space and Environment, Beihang University, Beijing 100191, China.
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12
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Cao X, Ji L, Lin X, Stevens WR, Tang M, Shang F, Tang S, Lu S. Comprehensive diagnosis of PCDD/F emission from three hazardous waste incinerators. ROYAL SOCIETY OPEN SCIENCE 2018; 5:172056. [PMID: 30109050 PMCID: PMC6083712 DOI: 10.1098/rsos.172056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 06/07/2018] [Indexed: 06/08/2023]
Abstract
Comprehensive diagnosis of polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/F) emissions was systematically conducted on three hazardous waste incinerators (HWIs). Results indicated that PCDD/F mainly existed in the solid phase before the bag filter. This was especially true for higher chlorinated dioxin and furan congeners (hexa-, hepta- and octa-). The aged bag filters tended to increase the gas-phase PCDD/F. Emissions also increased due to PCDD/F desorption from circulated scrubbing solution and plastic packing media used in the wet scrubber. The PCDD/F concentrations were elevated during the start-up process, reaching up to 5.4 times higher than those measured during the normal operating period. The ratios of PCDFs/PCDDs revealed that the surface-catalysed de novo synthesis was the dominant pathway of PCDD/F formation. Installation of more efficient fabric filters, intermittent replacement of circulated scrubbing solution will result in reduced PCDD/F emission. Additionally, 2,3,4,7,8-PeCDF correlated well with the international toxic equivalent quantity (I-TEQ) value, which suggests that 2,3,4,7,8-PeCDF could act as an I-TEQ indicator.
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Affiliation(s)
- Xuan Cao
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, People's Republic of China
- Zhejiang Fuchunjiang Environmental Technology Research Co. Ltd, Hangzhou 311401, People's Republic of China
| | - Longjie Ji
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, People's Republic of China
- National Engineering Laboratory for Site Remediation Technologies, Beijing Construction Engineering Group Environmental Remediation Co. Ltd, Beijing 100015, People's Republic of China
| | - Xiaoqing Lin
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, People's Republic of China
| | - William R. Stevens
- Zhejiang Fuchunjiang Environmental Technology Research Co. Ltd, Hangzhou 311401, People's Republic of China
- College of Health Sciences, Kentucky Christian University, Grayson, KY 41143, USA
| | - Minghui Tang
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, People's Republic of China
| | - Fanjie Shang
- Zhejiang Fuchunjiang Environmental Technology Research Co. Ltd, Hangzhou 311401, People's Republic of China
| | - Shaofu Tang
- Zhejiang Fuchunjiang Environmental Technology Research Co. Ltd, Hangzhou 311401, People's Republic of China
| | - Shengyong Lu
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, People's Republic of China
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Wang Q, Miyake Y, Tokumura M, Amagai T, Horii Y, Nojiri K, Ohtsuka N. Effects of characteristics of waste incinerator on emission rate of halogenated polycyclic aromatic hydrocarbon into environments. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 625:633-639. [PMID: 29304501 DOI: 10.1016/j.scitotenv.2017.12.323] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 12/25/2017] [Accepted: 12/28/2017] [Indexed: 06/07/2023]
Abstract
We determined the concentrations of halogenated polycyclic aromatic hydrocarbons (XPAHs), some of which are carcinogenic and/or mutagenic compounds, in fly and bottom ashes and stack gas collected from waste incinerators in Japan. The dominant XPAHs in stack gas were consistent with those in the urban atmosphere. The dioxin-like toxic equivalent (TEQ) concentration ranges of the XPAHs in stack gas, fly ash, and bottom ash were 0.00497-20.5ng-TEQm-3, 0.0541-101ng-TEQg-1, and 0.000914-2.00ng-TEQg-1, respectively. The TEQ concentrations of the XPAHs targeted in this study were higher than those of polychlorinated dibenzo-p-dioxins/dibenzofurans and polychlorinated biphenyls reported in the literature. The annual amounts of XPAHs produced in the waste incinerators ranged from 25.1 to 881g. The mass balance of XPAHs in each waste incinerator was calculated to evaluate the emission rate of XPAHs from waste incinerators. Less than 6.7% of the XPAHs produced in the waste incinerators were emitted into the atmosphere from the facilities in which the flue gas was treated by using a combination of bag filter and activated carbon. In contrast, from the facility using a bag filter only, approximately 50% of the XPAHs produced were emitted into the atmosphere. Thus, the flue gas treatment process appears to be a key determinant of the emission rate of XPAHs produced during waste incineration.
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Affiliation(s)
- Qi Wang
- Graduate Division of Nutritional and Environmental Science, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan.
| | - Yuichi Miyake
- Graduate Division of Nutritional and Environmental Science, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan.
| | - Masahiro Tokumura
- Graduate Division of Nutritional and Environmental Science, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan
| | - Takashi Amagai
- Graduate Division of Nutritional and Environmental Science, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan
| | - Yuichi Horii
- Center for Environmental Science in Saitama, 914 Kamitanadare, Kazo, Saitama 347-0115, Japan
| | - Kiyoshi Nojiri
- Center for Environmental Science in Saitama, 914 Kamitanadare, Kazo, Saitama 347-0115, Japan
| | - Nobutoshi Ohtsuka
- Center for Environmental Science in Saitama, 914 Kamitanadare, Kazo, Saitama 347-0115, Japan
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14
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Li G, Wu Q, Wang S, Duan Z, Su H, Zhang L, Li Z, Tang Y, Zhao M, Chen L, Liu K, Zhang Y. Improving Flue Gas Mercury Removal in Waste Incinerators by Optimization of Carbon Injection Rate. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:1940-1945. [PMID: 29338215 DOI: 10.1021/acs.est.7b05560] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
This study tested the mercury emission characteristics of six municipal solid waste incinerators (MSWIs) and recommended future mercury control via adjusting operational parameters. The results indicated that over 99% of the mercury in solid wastes ended in fly ash and flue gas, of which 3.3-66.3% was emitted to air through stack gas. Mercury in the stack gas was mainly in the form of oxidized mercury (Hg2+), the proportion (65.4-89.0%) of which was far higher than previous estimation (15%). Mercury removal efficiencies (MRE) of the tested incinerators were in the range of 33.6-95.2%. The impact of waste incineration capacity, gas flow, fly ash yield, and activated carbon (AC) injection on MRE were analyzed. We found that the MRE was significantly linearly correlated to the ratio of AC injection and fly ash yield (correlation coefficient = 0.98, significance <0.01). AC injection value is determined based on the control of dioxin emissions without considering mercury control in traditional design. To increase MRE of MSWIs, the AC injection should increase from around 100 mg·Nm-3 to 135 mg·Nm-3 for grate furnace combustor and 170 mg·Nm-3 for circulation fluidized bed combustor, so as to reach a MRE of 90%.
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Affiliation(s)
- Guoliang Li
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University , Beijing 100084, China
- State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China
| | - Qingru Wu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University , Beijing 100084, China
- State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China
| | - Shuxiao Wang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University , Beijing 100084, China
- State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China
| | - Zhenya Duan
- Power engineering and engineering Thermophysics, Qingdao University of Science and Technology , Qingdao, 266042, China
| | - Haitao Su
- Green energy (Hangzhou) enterprise management limited company, Hangzhou, 31005, China
| | - Lei Zhang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University , Beijing 100084, China
- State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China
| | - Zhijian Li
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University , Beijing 100084, China
- State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China
| | - Yi Tang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University , Beijing 100084, China
- State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China
| | - Minjiang Zhao
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University , Beijing 100084, China
- State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China
| | - Lei Chen
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University , Beijing 100084, China
- State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China
| | - Kaiyun Liu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University , Beijing 100084, China
- State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China
| | - Yong Zhang
- Green energy (Hangzhou) enterprise management limited company, Hangzhou, 31005, China
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15
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Lu JW, Zhang S, Hai J, Lei M. Status and perspectives of municipal solid waste incineration in China: A comparison with developed regions. WASTE MANAGEMENT (NEW YORK, N.Y.) 2017; 69:170-186. [PMID: 28408280 DOI: 10.1016/j.wasman.2017.04.014] [Citation(s) in RCA: 114] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2016] [Revised: 03/25/2017] [Accepted: 04/02/2017] [Indexed: 06/07/2023]
Abstract
With the rapid expansion of municipal solid waste (MSW) incineration, the applicability, technical status, and future improvement of MSW incineration attract much attention in China. This paper aims to be a sensible response, with the aid of a comparison between China and some representative developed regions including the EU, the U.S., Japan, South Korea, and Taiwan area. A large number of up-to-date data and information are collected to quantitatively and impartially support the comparison, which covers a wider range of key points including spatial distribution, temporal evolution, technologies, emissions, and perspectives. Analysis results show that MSW incineration is not an outdated choice; however, policy making should prevent the potentially insufficient utilization of MSW incinerators. The structure of MSW incineration technologies is changing in China. The ratio of plants using fluidized bed is decreasing due to various realistic reasons. Decision-makers would select suitable combustion technologies by comprehensive assessments, rather than just by costs. Air pollution control systems are improved with the implementation of China's new emission standard. However, MSW incineration in China is currently blamed for substandard emissions. The reasons include the particular elemental compositions of Chinese MSW, the lack of operating experience, deficient fund for compliance with the emission standard, and the lack of reliable supervisory measures. Some perspectives and suggestions from both technical and managerial aspects are given for the compliance with the emission standard. This paper can provide strategic enlightenments for MSW management in China and other developing countries.
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Affiliation(s)
- Jia-Wei Lu
- South China Institute of Environmental Sciences, Ministry of Environmental Protection, Guangzhou 510655, China
| | - Sukun Zhang
- South China Institute of Environmental Sciences, Ministry of Environmental Protection, Guangzhou 510655, China
| | - Jing Hai
- South China Institute of Environmental Sciences, Ministry of Environmental Protection, Guangzhou 510655, China.
| | - Ming Lei
- South China Institute of Environmental Sciences, Ministry of Environmental Protection, Guangzhou 510655, China
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16
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Zhan MX, Fu JY, Chen T, Lin XQ, Li XD, Yan JH, Buekens A. Suppression of dioxins by S-N inhibitors in pilot-scale experiments. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:16463-16477. [PMID: 27164888 DOI: 10.1007/s11356-016-6401-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 03/01/2016] [Indexed: 06/05/2023]
Abstract
S-N inhibitors like thiourea and sewage sludge decomposition gases (SDG) are relatively novel dioxins suppressants and their efficiencies are proven in numerous lab-scale experiments. In this study, the suppression effects of both thiourea and SDG on the formation of dioxins are systematically tested in a pilot-scale system, situated at the bypass of a hazardous waste incinerator (HWI). Moreover, a flue gas recirculation system is used to get high dioxin suppression efficiencies. Operating experience shows that this system is capable of stable operation and to keep gaseous suppressant compounds at a high and desirable molar ratio (S + N)/Cl level in the flue gas. The suppression efficiencies of dioxins are investigated in flue gas both without and with addition of S-N inhibitors. A dioxin reduction of more than 80 % is already achieved when the (S + N)/Cl molar ratio is increased to ca. 2.20. When this (S + N)/Cl molar ratio has augmented to 4.18 by applying suppressant recirculation, the residual PCDD/Fs concentration in the flue gas shrank from 1.22 to 0.08 ng I-TEQ/Nm(3). Furthermore, the congener distribution of dioxins is analysed to find some possible explanation or suppression mechanism. In addition, a correlation analysis between (S + N)/Cl molar ratios and PCDD/Fs is also conducted to investigate the chief functional compounds for dioxin suppression.
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Affiliation(s)
- Ming-Xiu Zhan
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, China
| | - Jian-Ying Fu
- China United Engineering Corporation, Hangzhou, 310052, People's Republic of China
| | - Tong Chen
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, China.
| | - Xiao-Qing Lin
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, China
| | - Xiao-Dong Li
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, China
| | - Jian-Hua Yan
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, China
| | - Alfons Buekens
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, China
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17
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Yu MF, Li XD, Chen T, Lu SY, Yan JH. Low temperature destruction of PCDD/Fs by catalysis coupled with activated carbon. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:5459-5467. [PMID: 26566615 DOI: 10.1007/s11356-015-5773-z] [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: 08/18/2015] [Accepted: 11/05/2015] [Indexed: 06/05/2023]
Abstract
In order to enhance the oxidation and adsorption capacity of catalyst, two kinds of activated carbon (AC) are mechanically mixed with V2O5-WO3/TiO2 catalyst respectively. In this study, the mixtures (M-1: catalyst mixing with AC based on lignite; M-2: the one on coconut shell) are investigated to destroy high concentration (9.8 ng I-TEQ Nm(-3)) PCDD/Fs at low temperature (160 °C). Adding AC into the catalyst obviously increases removal efficiency (RE) and destruction efficiency (DE). However, M-2 presents higher RE value and lower DE value compared with M-1 at the same conditions as the stronger adsorption capacity of AC based on coconut shell. For the M-2 mixture, RE values are decreasing while DE values show an opposite trend with the ratios of catalyst to AC increasing. Oxygen plays a positive role on the destruction of PCDD/Fs by accelerating the conversion of V(4+)Ox and V(5+)Ox. Adjusting oxygen content from 0 to 20 % could increase the DE value from 27.4 to 82.2 % for the M-1 and from 15.8 to 68.9 % for the M-2. In the presence of ozone, a dark brown flock will be generated when the ratio of AC and catalyst is 4:1 due to the reaction between AC and ozone, which results in the lower RE and DE values. The RE and DE values reach the maximum of 96.3 %, 90.6 % in this paper, respectively, when the ratio of AC and catalyst is 1:1 with ozone. Finally, the regenerating of mixture is investigated. Most of dioxin residues in the mixture are desorbed and oxidized by catalysis at 200 °C in the presence of oxygen.
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Affiliation(s)
- Ming-Feng Yu
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Zheda Road 38#, Hangzhou, 310027, China
| | - Xiao-Dong Li
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Zheda Road 38#, Hangzhou, 310027, China.
| | - Tong Chen
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Zheda Road 38#, Hangzhou, 310027, China
| | - Sheng-Yong Lu
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Zheda Road 38#, Hangzhou, 310027, China
| | - Jian-Hua Yan
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Zheda Road 38#, Hangzhou, 310027, China
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18
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Zhou XJ, Buekens A, Li XD, Ni MJ, Cen KF. Adsorption of polychlorinated dibenzo-p-dioxins/dibenzofurans on activated carbon from hexane. CHEMOSPHERE 2016; 144:1264-1269. [PMID: 26476048 DOI: 10.1016/j.chemosphere.2015.10.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2015] [Revised: 09/20/2015] [Accepted: 10/01/2015] [Indexed: 06/05/2023]
Abstract
Activated carbon is widely used to abate dioxins and dioxin-like compounds from flue gas. Comparing commercial samples regarding their potential to adsorb dioxins may proceed by using test columns, yet it takes many measurements to characterise the retention and breakthrough of dioxins. In this study, commercial activated carbon samples are evaluated during tests to remove trace amounts of dioxins dissolved in n-hexane. The solution was prepared from fly ash collected from a municipal solid waste incinerator. The key variables selected were the concentration of dioxins in n-hexane and the dosage of activated carbon. Both polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) showed very high removal efficiencies (94.7%-98.0% for PCDDs and 99.7%-99.8% for PCDFs). The presence of a large excess of n-hexane solvent had little effect on the removal efficiency of PCDD/Fs. The adsorbed PCDD/Fs showed a linear correlation (R(2) > 0.98) with the initial concentrations. Comparative analysis of adsorption isotherms showed that a linear Henry isotherm fitted better the experimental data (R(2) = 0.99 both for PCDDs and PCDFs) than the more usual Freundlich isotherm (R(2) = 0.88 for PCDDs and 0.77 for PCDFs). Finally, the results of fingerprint analysis indicated that dioxin fingerprint (weight proportion of different congeners) on activated carbon after adsorption did not change from that in hexane.
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Affiliation(s)
- Xu-Jian Zhou
- State Key Laboratory of Clean Energy Utilization, College of Energy Engineering, Zhejiang University, Zheda Road 38#, Hangzhou 310027, China
| | - Alfons Buekens
- State Key Laboratory of Clean Energy Utilization, College of Energy Engineering, Zhejiang University, Zheda Road 38#, Hangzhou 310027, China
| | - Xiao-Dong Li
- State Key Laboratory of Clean Energy Utilization, College of Energy Engineering, Zhejiang University, Zheda Road 38#, Hangzhou 310027, China.
| | - Ming-Jiang Ni
- State Key Laboratory of Clean Energy Utilization, College of Energy Engineering, Zhejiang University, Zheda Road 38#, Hangzhou 310027, China
| | - Ke-Fa Cen
- State Key Laboratory of Clean Energy Utilization, College of Energy Engineering, Zhejiang University, Zheda Road 38#, Hangzhou 310027, China
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19
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Hsu WT, Hung PC, Chang MB. Catalytic destruction vs. adsorption in controlling dioxin emission. WASTE MANAGEMENT (NEW YORK, N.Y.) 2015; 46:257-264. [PMID: 26350401 DOI: 10.1016/j.wasman.2015.09.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 07/11/2015] [Accepted: 09/01/2015] [Indexed: 06/05/2023]
Abstract
This study investigates the removal efficiencies of PCDD/Fs achieved with a catalytic filter (CF) and with activated carbon injection followed by bag filter (ACI+BF) as applied in an industrial waste incinerator (IWI) and a hazardous waste incinerator (HWI), respectively. Catalytic filtration has been successfully applied to remove PCDD/Fs from gas streams. Comparing the CF to the ACI+BF system, it appears that the PCDD/F removal efficiency achieved with a CF is higher than that of an ACI+BF system. The PCDD/F emissions from both incinerators are well controlled to meet the regulatory limit of 0.1 ng I-TEQ/Nm(3). Additionally, the PCDD/F concentration in BF ash is higher than the regulation limit of Taiwan (1.0 ng I-TEQ/g). In contrast, the PCDD/F concentration in CF ash is only 0.274 ng I-TEQ/g. The difference is attributed to the fact that the ACI+BF system just transfers PCDD/Fs from gas phase to solid phase and further increases the PCDD/F concentration in fly ash, while CF technology effectively destroys the gas-phase PCDD/Fs. Therefore, the disposal of the fly ash discharged from CF would be less expensive compared with the fly ash discharged from the ACI+BF system. In this study, the PCDD/F emission factors of both incinerators are also established.
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Affiliation(s)
- Wei Ting Hsu
- Graduate Institute of Environmental Engineering, National Central University, 300 Jhong-da Road, Jhongli, Taoyuan 32001, Taiwan, Republic of China
| | - Pao Chen Hung
- Graduate Institute of Environmental Engineering, National Central University, 300 Jhong-da Road, Jhongli, Taoyuan 32001, Taiwan, Republic of China
| | - Moo Been Chang
- Graduate Institute of Environmental Engineering, National Central University, 300 Jhong-da Road, Jhongli, Taoyuan 32001, Taiwan, Republic of China.
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20
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Determination of optimum dose of adsorbent for PCDD/F removal in the flue gas of a medical waste incineration plant. Chem Eng Res Des 2015. [DOI: 10.1016/j.cherd.2015.10.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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21
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Zhou XJ, Li XD, Ni MJ, Cen KF. Removal efficiencies for 136 tetra- through octa-chlorinated dibenzo-p-dioxins and dibenzofuran congeners with activated carbons. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2015; 22:17691-17696. [PMID: 26154037 DOI: 10.1007/s11356-015-4940-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Accepted: 06/22/2015] [Indexed: 06/04/2023]
Abstract
In this study, the removal efficiency of 136 tetra- to octa-chlorinated dibenzo-p-dioxin (CDD)/furan (F) congeners from a nitrogen + oxygen carrier gas was studied using a laboratory-scale, fixed bed adsorption system. Two kinds of activated carbon with dissimilar pore structures were used as adsorbents. The total concentration of polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) in the source gas was 541 ng/Nm(3) and that of the 17 toxic 2,3,7,8-substituted PCDD/Fs 96.35 ng/Nm(3), accounting for 17.8% of the total original weight amount. Their toxic equivalent quantity (TEQ) was 8.31 ng I-TEQ/Nm(3). For both activated carbons, the removal efficiencies of the ten PCDD/F homologue groups rise with chlorine substitution number. The removal efficiencies vary approximately as a power function of vapor pressure (correlation coefficients r(2) = 0.93 and 0.81, respectively). Competitive adsorption and desorption occur as adsorption time went on, causing elution of the lower chlorinated homologues, i.e. tetra-CDD/F and Penta-CDD/F congeners. In addition, there are significantly different concentration distributions for isomers in the same homologue groups. However, their removal efficiencies have weak correlation with their initial concentrations. The correlation coefficients are from -0.47 to 0.32 and from -0.57 to 0.46 respectively for the two kinds of activated carbons.
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Affiliation(s)
- Xu-Jian Zhou
- State Key Laboratory of Clean Energy Utilization, College of Energy Engineering, Zhejiang University, Zheda Road 38#, Hangzhou, 310027, China
| | - Xiao-Dong Li
- State Key Laboratory of Clean Energy Utilization, College of Energy Engineering, Zhejiang University, Zheda Road 38#, Hangzhou, 310027, China.
| | - Ming-Jiang Ni
- State Key Laboratory of Clean Energy Utilization, College of Energy Engineering, Zhejiang University, Zheda Road 38#, Hangzhou, 310027, China
| | - Ke-Fa Cen
- State Key Laboratory of Clean Energy Utilization, College of Energy Engineering, Zhejiang University, Zheda Road 38#, Hangzhou, 310027, China
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22
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Zhou X, Li X, Xu S, Zhao X, Ni M, Cen K. Comparison of adsorption behavior of PCDD/Fs on carbon nanotubes and activated carbons in a bench-scale dioxin generating system. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2015; 22:10463-10470. [PMID: 25728198 DOI: 10.1007/s11356-015-4180-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2014] [Accepted: 01/28/2015] [Indexed: 06/04/2023]
Abstract
Porous carbon-based materials are commonly used to remove various organic and inorganic pollutants from gaseous and liquid effluents and products. In this study, the adsorption of dioxins on both activated carbons and multi-walled carbon nanotube was internally compared, via series of bench scale experiments. A laboratory-scale dioxin generator was applied to generate PCDD/Fs with constant concentration (8.3 ng I-TEQ/Nm(3)). The results confirm that high-chlorinated congeners are more easily adsorbed on both activated carbons and carbon nanotubes than low-chlorinated congeners. Carbon nanotubes also achieved higher adsorption efficiency than activated carbons even though they have smaller BET-surface. Carbon nanotubes reached the total removal efficiency over 86.8 % to be compared with removal efficiencies of only 70.0 and 54.2 % for the two other activated carbons tested. In addition, because of different adsorption mechanisms, the removal efficiencies of carbon nanotubes dropped more slowly with time than was the case for activated carbons. It could be attributed to the abundant mesopores distributed in the surface of carbon nanotubes. They enhanced the pore filled process of dioxin molecules during adsorption. In addition, strong interactions between the two benzene rings of dioxin molecules and the hexagonal arrays of carbon atoms in the surface make carbon nanotubes have bigger adsorption capacity.
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Affiliation(s)
- Xujian Zhou
- State Key Laboratory of Clean Energy Utilization, The College of Energy Engineering, Zhejiang University, Zheda Road 38#, Hangzhou, 310027, China
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23
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Atkinson JD, Hung PC, Zhang Z, Chang MB, Yan Z, Rood MJ. Adsorption and destruction of PCDD/Fs using surface-functionalized activated carbons. CHEMOSPHERE 2015; 118:136-142. [PMID: 25150825 DOI: 10.1016/j.chemosphere.2014.07.055] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 07/06/2014] [Accepted: 07/20/2014] [Indexed: 06/03/2023]
Abstract
Activated carbon adsorbs polychlorinated dibenzo-p-dioxins and -furans (PCDD/Fs) from gas streams but can simultaneously generate PCDD/Fs via de novo synthesis, increasing an already serious disposal problem for the spent sorbent. To increase activated carbon's PCDD/F sorption capacity and lifetime while reducing the impact of hazardous waste, it is beneficial to develop carbon-based sorbents that simultaneously destroy PCDD/Fs while adsorbing the toxic chemicals from gas streams. In this work, hydrogen-treated and surface-functionalized (i.e., oxygen, bromine, nitrogen, and sulfur) activated carbons are tested in a bench-scale reactor as adsorbents for PCDD/Fs. All tested carbons adsorb PCDD/F efficiently, with international toxic equivalent removal efficiencies exceeding 99% and mass removal efficiencies exceeding 98% for all but one tested material. Hydrogen-treated materials caused negligible destruction and possible generation of PCDD/Fs, with total mass balances between 100% and 107%. All tested surface-functionalized carbons, regardless of functionality, destroyed PCDD/Fs, with total mass balances between 73% and 96%. Free radicals on the carbon surface provided by different functional groups may contribute to PCDD/F destruction, as has been hypothesized in the literature. Surface-functionalized materials preferentially destroyed higher-order (more chlorine) congeners, supporting a dechlorination mechanism as opposed to oxidation. Carbons impregnated with sulfur are particularly effective at destroying PCDD/Fs, with destruction efficiency improving with increasing sulfur content to as high as 27%. This is relevant because sulfur-treated carbons are used for mercury adsorption, increasing the possibility of multi-pollutant control.
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Affiliation(s)
- J D Atkinson
- Department of Civil and Environmental Engineering, University of Illinois, 205 N. Mathews Ave., Urbana, IL 61801, USA
| | - P C Hung
- Graduate Institute of Environmental Engineering, National Central University, Chongli City, Taiwan
| | - Z Zhang
- Department of Civil and Environmental Engineering, University of Illinois, 205 N. Mathews Ave., Urbana, IL 61801, USA; State Key Laboratory of Heavy Oil Processing, Key Laboratory of Catalysis, CNPC, China University of Petroleum, Qingdao 266580, China
| | - M B Chang
- Graduate Institute of Environmental Engineering, National Central University, Chongli City, Taiwan.
| | - Z Yan
- State Key Laboratory of Heavy Oil Processing, Key Laboratory of Catalysis, CNPC, China University of Petroleum, Qingdao 266580, China
| | - M J Rood
- Department of Civil and Environmental Engineering, University of Illinois, 205 N. Mathews Ave., Urbana, IL 61801, USA.
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24
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Hung PC, Chang CC, Chang SH, Chang MB. Characteristics of PCDD/F emissions from secondary copper smelting industry. CHEMOSPHERE 2015; 118:148-155. [PMID: 25150827 DOI: 10.1016/j.chemosphere.2014.07.064] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 07/04/2014] [Accepted: 07/20/2014] [Indexed: 06/03/2023]
Abstract
Characteristics and mechanisms of PCDD/F formation with different feed materials in secondary copper smelting industry are investigated. The results indicate that PCDD/Fs are significantly formed even with the reaction time less than 0.1s, especially when the material containing high residues (Cu3) is fed. High copper content (65±2%) in the feed material enhances PCDD/F formation rate. Memory effect and de novo synthesis are two important mechanisms leading to PCDD/F formation. PCDD/F concentrations at the cyclone's inlet are between 2.92 and 12.4ng-TEQNm(-3) and increase with increasing residue content in the feed material. Two regions are identified for high potential of PCDD/F formation including the brass melt surface of the induction furnace and piping before the induced draft fan of the inlet hood. PCDD/Fs in flue gas are effectively removed with a cyclone and bag filter at low operating temperatures (<60°C) to meet the emission limit of 1.0ng-TEQNm(-3). 1,2,3,4,6,7,8-HpCDF has the largest mass fraction of PCDD/Fs and can serve as a fingerprint for emissions from secondary copper smelting processes. The total emission factor of PCDD/Fs from flue gas, residual and fly ash in the secondary copper smelting process investigated is 22.01μg-TEQtonne(-1).
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Affiliation(s)
- Pao Chen Hung
- Institute of Environmental Engineering, National Central University, 300 Jhong-da Rd., Jhong-li City, Taiwan, ROC
| | - Chia Chia Chang
- Institute of Environmental Engineering, National Central University, 300 Jhong-da Rd., Jhong-li City, Taiwan, ROC
| | - Shu Hao Chang
- Institute of Environmental Engineering, National Central University, 300 Jhong-da Rd., Jhong-li City, Taiwan, ROC
| | - Moo Been Chang
- Institute of Environmental Engineering, National Central University, 300 Jhong-da Rd., Jhong-li City, Taiwan, ROC.
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25
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Ren Y, Li X, Ji S, Lu S, Buekens A, Yan J. Removal of gaseous HxCBz by gliding arc plasma in combination with a catalyst. CHEMOSPHERE 2014; 117:730-736. [PMID: 25461941 DOI: 10.1016/j.chemosphere.2014.09.091] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 09/25/2014] [Accepted: 09/30/2014] [Indexed: 06/04/2023]
Abstract
Hexachlorobenzene (HxCBz) owns the chemical structure of one benzene ring and six H atoms substituted by Cl atoms and it is a persistent organic pollutant present in flue gas from municipal solid waste incineration as an important precursor of dioxins. Its removal was studied using gliding arc plasma treatment, coupled downstream with a V2O5–WO3–TiO2 catalyst. Several parameters (input voltage, O2 concentration, catalytic temperature and catalyst position) all influenced its removal efficiency (RE). Optimal parameter settings were tentatively determined, i.e., an input voltage of 15 kV, the temperature of the catalyst (250 °C), and the O2 concentration (30 vol% O2) tested at a single, fixed concentration of gaseous HxCBz (71.6 ng Nm−3). A maximum RE of 76 ± 3% HxCBz was attained, with the plasma and coupled catalyst combined. Two destruction pathways, incorporating dechlorination and oxidation reactions, were recognised, both based on the detection of end- and intermediate products as well as of active species produced by the plasma. These end- and intermediate products included: low chlorinated polychlorobenzenes (mainly 1,2,4-Trichlorobenzene) as well as hydrocarbons (mainly C2H6), HCOOH, CH4, CO, CO2, etc.
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Affiliation(s)
- Yong Ren
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, Zhejiang, China
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26
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Liu ZS, Li WK, Hung MJ. Simultaneous removal of sulfur dioxide and polycyclic aromatic hydrocarbons from incineration flue gas using activated carbon fibers. JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION (1995) 2014; 64:1038-1044. [PMID: 25283001 DOI: 10.1080/10962247.2014.922519] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 05/02/2014] [Indexed: 06/03/2023]
Abstract
Incineration flue gas contains polycyclic aromatic hydrocarbons (PAHs) and sulfur dioxide (SO2). The effects of SO2 concentration (0, 350, 750, and 1000 ppm), reaction temperature (160, 200, and 280 degrees C), and the type of activated carbon fibers (ACFs) on the removal of SO2 and PAHs by ACFs were examined in this study. A fluidized bed incinerator was used to simulate practical incineration flue gas. It was found that the presence of SO2 in the incineration flue gas could drastically decrease removal of PAHs because of competitive adsorption. The effect of rise in the reaction temperature from 160 to 280 degrees C on removal of PAHs was greater than that on SO2 removal at an SO2 concentration of 750 ppm. Among the three ACFs studied, ACF-B, with the highest microporous volume, highest O content, and the tightest structure, was the best adsorbent for removing SO2 and PAHs when these gases coexisted in the incineration flue gas. Implications: Simultaneous adsorption of sulfur dioxide (SO2) and polycyclic aromatic hydrocarbons (PAHs) emitted from incineration flue gas onto activated carbon fibers (ACFs) meant to devise a new technique showed that the presence of SO2 in the incineration flue gas leads to a drastic decrease in removal of PAHs because of competitive adsorption. Reaction temperature had a greater influence on PAHs removal than on SO2 removal. ACF-B, with the highest microporous volume, highest O content, and tightest structure among the three studied ACFs, was found to be the best adsorbent for removing SO2 and PAHs.
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27
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Addeck A, Croes K, Van Langenhove K, Denison MS, Elhamalawy A, Elskens M, Baeyens W. Time-integrated monitoring of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) in urban and industrial wastewaters using a ceramic toximeter and the CALUX bioassay. CHEMOSPHERE 2014; 94:27-35. [PMID: 24075528 PMCID: PMC4308619 DOI: 10.1016/j.chemosphere.2013.08.075] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Revised: 08/14/2013] [Accepted: 08/26/2013] [Indexed: 06/02/2023]
Abstract
The ceramic toximeter as a passive sampler in combination with the CALUX bioassay was utilized as a time-integrated pollution-assessment technique for dioxin-like PCDD/Fs in wastewaters. Toximeters filled with XCARB and enclosed in stainless steel cages were submerged in wastewater of Belbeis drainage-canal and EMAK paper-mill, located in Egypt, for 28 days. Two samplers were removed every week from each site. Extracts from toximeters, from bottom-sediments, and from paper-mill sludge were analyzed by the CALUX. Results showed a regular increase in the amounts of PCDD/Fs trapped by the toximeters as sampling time increased. Time-weighted average concentrations (TWA) of PCDD/Fs in the wastewaters of the drainage-canal and paper-mill were 231 (214-281) and 26 (24.1-32.6) pg-BEQL(-1), respectively. Compared to literature data, this means a high pollution level for the drainage-canal water, while the pollution level in the paper-mill wastewater is similar to that reported for other paper mills. The PCDD/Fs levels in the drainage-canal bottom-sediments and in the paper-mill sludge were 8.3 and 14.6 pg-BEQg(-1) dry-weight, at the lower end of internationally reported values in similar compartments. The sampling rate of the tested toximeters for dissolved PCDD/Fs was about 3.6 mL d(-1). Sediment/water partitioning coefficient logKd of PCDD/Fs in the drainage-canal and the paper-mill was 1.42 and 2.70 respectively. The organic-carbon normalized partition coefficient logKoc was 4.17 and 3.19 respectively, and is lower than the reported values for other sites.
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Affiliation(s)
- Amr Addeck
- Department of Analytical and Environmental Chemistry, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium.
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28
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Liu ZS, Chen JY, Peng YH. Activated carbon fibers impregnated with Pd and Pt catalysts for toluene removal. JOURNAL OF HAZARDOUS MATERIALS 2013; 256-257:49-55. [PMID: 23669790 DOI: 10.1016/j.jhazmat.2013.04.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 03/19/2013] [Accepted: 04/07/2013] [Indexed: 06/02/2023]
Abstract
Few studies have investigated the use of activated carbon fibers (ACFs) impregnated with noble metals for the catalytic oxidation of volatile organic compounds (VOCs). This study determined the removal efficiency of toluene as a function of time over ACF-supported metal catalysts. Two catalysts (Pt and Pd), five reaction temperatures (120, 150, 200, 250, and 300°C), and three oxygen contents (6%, 10%, and 21%) were investigated to determine the removal of toluene. To study the effects of the characteristics of the catalysts on toluene removal, the composition and morphology of the ACFs were analyzed using the BET, XPS, ICP, and FE-SEM. The results showed that the 0.42%Pd/ACFs showed greater activity for toluene removal than did 2.68%Pt/ACFs at a reaction temperature of 200°C and an oxygen content of 10%. The main removal mechanism of toluene over the 2.68%Pt/ACFs at reaction temperatures less than 200°C was adsorption. The long-term catalytic activity of the 2.68%Pt/ACFs for toluene removal at a reaction temperature of 250°C and an oxygen content of 10% could be obtained. Furthermore, toluene removal over the 2.68%Pt/ACFs at 200°C could be enhanced with increasing oxygen content.
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Affiliation(s)
- Zhen-Shu Liu
- Department of Safety, Health and Environmental Engineering, Ming Chi University of Technology, Taishan District, New Taipei City 24301, Taiwan, ROC.
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29
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Bunsan S, Chen WY, Chen HW, Chuang YH, Grisdanurak N. Modeling the dioxin emission of a municipal solid waste incinerator using neural networks. CHEMOSPHERE 2013; 92:258-264. [PMID: 23562548 DOI: 10.1016/j.chemosphere.2013.01.083] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 01/10/2013] [Accepted: 01/19/2013] [Indexed: 06/02/2023]
Abstract
Incineration is considered as an efficient approach in dealing with the increasing demand for municipal and industrial solid waste treatment, especially in areas without sufficient land resources. Facing the concern of health risk, the toxic pollutants emitted from incinerators have attracted much attention from environmentalists, even though this technology is capable of reducing solid waste volume and demand for landfill areas, together with plenty of energy generation. To reduce the negative impacts of toxic chemicals emitted from incinerators, various monitoring and control plans are made not only for use in facilities performance evaluation but also better control of operation for stable effluent quality. How to screen out the key variables from massive observed and control variables for modeling the dioxin emission has become an important issue in incinerator operation and pollution prevention. For these reasons, this study used 4-year monitoring data of an incinerator in Taiwan as a case study, and developed a prediction model based on an artificial neural network (ANN) to forecast the dioxin emission. By doing this, a simplified monitoring strategy for incinerators with regarding to dioxin emission control can be achieved. The result indicated that the prediction model based on a back-propagation neural network is a promising method to deal with complex and non-linear data with the help of statistics in screening out the useful variables for modeling. The suitable architecture of an ANN for using in the dioxin prediction consists of 5 input factors, 3 basic layers with 8 hidden nodes. The R(2) was found to equal 0.99 in both the training and testing steps. In addition, sensitivity analysis can identify the most significant variables for the dioxin emission. From the obtained results, the frequency of activated carbon injection showed as the factor of highest relative importance for the dioxin emission.
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Affiliation(s)
- Sond Bunsan
- International Postgraduate Programs in Environmental Management, Graduate School, Chulalongkorn University, Bangkok 10330, Thailand
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30
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Xu Q, Zhu X, Henkelmann B, Schrammn KW, Chen J, Ni Y, Wang W, Pfister G, Mu J, Qin S, Li Y. Simultaneous monitoring of PCB profiles in the urban air of Dalian, China with active and passive samplings. J Environ Sci (China) 2013; 25:133-43. [PMID: 23586308 DOI: 10.1016/s1001-0742(12)60030-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The concentration of polychlorinated biphenyls (PCBs) in the urban air of Dalian, China was monitored from November 2009 to October 2010 with active high-volume sampler and semipermeable membrane device (SPMD) passive sampler. The concentration of PCBs (particle + gas) (SigmaPCBs) ranged from 18.6 to 91.0 pg/m3, with an average of 50.9 pg/m3, and the most abundant dioxin-like PCB (DL-PCBs) was PCB118. The WHO-TEQ values of DL-PCBs were 3.6-22.1 fg/m3, with an average of 8.5 fg/m3, and PCB126 was the maximum contributor to SigmaTEQ. There was a much larger amount of PCBs in the gas phase than in the particulate phase. The dominant PCB components were lower and middle molecular weight PCBs. With increasing chlorination level, the concentration of the PCB congeners in the air decreased. The gas-particulate partitioning of PCBs was different for the four seasons. The gas-particulate partitioning coefficients (logKp) vs. subcooled liquid vapor pressures (logP(L)0) of PCBs had reasonable correlations for different sampling sites and seasons. The absorption mechanism contributed more to the gas-particulate partitioning process than adsorption. Correlation analysis of meteorological parameters with the concentration of PCBs was conducted using SPSS packages. The ambient temperature and atmospheric pressure were important factors influencing the concentration of PCBs in the air. The distribution pattern of the congeners of PCBs and the dominant contributors to DL-PCBs and TEQ in active samples and SPMDs passive samples were similar. SPMD mainly sequestrated gas phase PCBs.
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Affiliation(s)
- Qian Xu
- School of Environmental and Chemical Engineering, Dalian Jiaotong University, Dalian 116028, China
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31
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Hung PC, Lo WC, Chi KH, Chang SH, Chang MB. Reduction of dioxin emission by a multi-layer reactor with bead-shaped activated carbon in simulated gas stream and real flue gas of a sinter plant. CHEMOSPHERE 2011; 82:72-77. [PMID: 21040943 DOI: 10.1016/j.chemosphere.2010.10.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Revised: 08/18/2010] [Accepted: 10/03/2010] [Indexed: 05/30/2023]
Abstract
A laboratory-scale multi-layer system was developed for the adsorption of PCDD/Fs from gas streams at various operating conditions, including gas flow rate, operating temperature and water vapor content. Excellent PCDD/F removal efficiency (>99.99%) was achieved with the multi-layer design with bead-shaped activated carbons (BACs). The PCDD/F removal efficiency achieved with the first layer adsorption bed decreased as the gas flow rate was increased due to the decrease of the gas retention time. The PCDD/F concentrations measured at the outlet of the third layer adsorption bed were all lower than 0.1 ng I-TEQ Nm⁻³. The PCDD/Fs desorbed from BAC were mainly lowly chlorinated congeners and the PCDD/F outlet concentrations increased as the operating temperature was increased. In addition, the results of pilot-scale experiment (real flue gases of an iron ore sintering plant) indicated that as the gas flow rate was controlled at 15 slpm, the removal efficiencies of PCDD/F congeners achieved with the multi-layer reactor with BAC were better than that in higher gas flow rate condition (20 slpm). Overall, the lab-scale and pilot-scale experiments indicated that PCDD/F removal achieved by multi-layer reactor with BAC strongly depended on the flow rate of the gas stream to be treated.
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Affiliation(s)
- Pao Chen Hung
- Graduate Institute of Environmental Engineering, National Central University, Chungli, Taiwan
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32
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Gao Y, Zhang H, Chen J. Vapor-phase sorption of hexachlorobenzene on typical municipal solid waste (MSW) incineration fly ashes, clay minerals and activated carbon. CHEMOSPHERE 2010; 81:1012-1017. [PMID: 20875668 DOI: 10.1016/j.chemosphere.2010.09.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Revised: 07/15/2010] [Accepted: 09/02/2010] [Indexed: 05/29/2023]
Abstract
Column sorption experiments were conducted at 330°C and 250°C to study the vapor-phase sorption of hexachlorobenzene (HCB) on two kinds of municipal solid waste (MSW) incinerator fly ashes, kaolinite, montmorillonite and activated carbon (AC). Both Freundlich equation and linear equation well fitted the sorption isotherms of HCB vapor on fly ashes and clay minerals at 330°C (r(2)>0.87), while the sorption isotherm of HCB vapor on AC at 330°C was in the shape of Brunauer type-II adsorption. Catalytic dechlorination of HCB was found to occur on the surface of fly ashes, and pentachlorobenzene was the only dechlorination product detected in the effluent gas. Increasing temperature decreased the sorption of HCB vapor on fly ashes, and promoted the catalytic dechlorination of HCB. On the assumption that the organic carbon and clay minerals in fly ash were derived from AC, kaolinite and montmorillonite, the relative contributions of these components to the apparent sorption capacity of fly ashes at 330°C were estimated. It was found that very small percentage of AC contributed the most to the apparent sorption of HCB vapor on fly ash. The sorption coefficient of HCB on montmorillonite at 250°C was 37 times higher than that at 330°C, suggesting montmorillonite could be a kind of low-cost sorbent to effectively reduce the emission of vapor-phase organochlorine compounds from MSW incinerators.
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Affiliation(s)
- Yuan Gao
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
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33
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Hung PC, Chang SH, Chi KH, Chang MB. Degradation of gaseous dioxin-like compounds with dielectric barrier discharges. JOURNAL OF HAZARDOUS MATERIALS 2010; 182:246-251. [PMID: 20605067 DOI: 10.1016/j.jhazmat.2010.06.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2010] [Revised: 06/03/2010] [Accepted: 06/07/2010] [Indexed: 05/29/2023]
Abstract
Developing effective technologies to reduce dioxin emissions has become an important issue in the research and industrial fields. In this study, a dioxin-containing gas stream generating system was applied to evaluate the effectiveness of dielectric barrier discharge (DBD) plasma technology for the destruction of dioxin-like compounds. The results indicate that the destruction efficiencies of dioxin-like compounds achieved with DBD plasma strongly depend on the composition of the simulated gas stream. As the DBD plasma is operated with the simulated gas stream containing 20% water vapor, around 74% PCDDs and 89% PCDFs can be destroyed by DBD plasma. UV, electrons, and OH radicals are generated via the DBD plasma process and react with the dioxin-like compounds in the gas stream. Dechlorination via UV and electrons and decomposition via OH radicals occur at the same time and significantly increase the destruction efficiency of PCDD/Fs in the presence of oxygen and water vapor. Additionally, the total toxicity destruction of dioxin-like compounds with the input energy of 1 kJ increases from 1.47 to 3.06 ng-TEQ(WHO) as the water vapor is incorporated into the gas stream.
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Affiliation(s)
- Pao Chen Hung
- Graduate Institute of Environmental Engineering, National Central University, Chungli 320, Taiwan
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34
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Chang YM, Hung CY, Chen JH, Chang CT, Chen CH. Minimum feeding rate of activated carbon to control dioxin emissions from a large-scale municipal solid waste incinerator. JOURNAL OF HAZARDOUS MATERIALS 2009; 161:1436-1443. [PMID: 18599199 DOI: 10.1016/j.jhazmat.2008.04.128] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2007] [Revised: 04/29/2008] [Accepted: 04/29/2008] [Indexed: 05/26/2023]
Abstract
To obtain a minimum feeding rate (F(min)) of activated carbon (AC), a series of measurements on dioxin emission concentration were carried out in a large-scale municipal solid waste incinerator. It was found that dioxin removal efficiency (eta) increased with an increase in AC feeding concentration. This had an almost linear function to F/Q when F/Q was less than 65 g/Nm(3), where F was the AC feeding rate (mg/min), and Q was the volumetric flow rate of flue gas (Nm(3)/min). However, it did not seem to be affected by F/Q, when F/Q was larger than 150 mg/Nm(3). On the basis of the experimental data obtained in this study, the removal efficiency of dioxins by the application of AC could be correlated as eta (%)=100/[1.0+(40.2/(F/Q)(3))]. It is valid in appropriate conditions (F/Q=10-300 mg/Nm(3)) suggested by the study with a statistical error of +/-18%. The correlation would be applied to estimate the dioxin removal efficiency (eta) using the F/Q value. For engineering applications, the (F/Q)(min) could be solved using a graphic illustration method, by which the minimum feeding rate (F) was obtained if the flue gas volumetric flow rate (Q) was known.
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Affiliation(s)
- Yu-Min Chang
- Institute of Environmental Engineering and Management, National Taipei University of Technology, No. 3, Section 1, Chung-Shiao E. Road, Taipei, Taiwan.
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Yokohama N, Otaka H, Minato I, Nakata M. Evaluation of gas-particle partition of dioxins in flue gas I: evaluation of gasification behavior of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in fly ash by thermal treatment. JOURNAL OF HAZARDOUS MATERIALS 2008; 153:395-403. [PMID: 18054160 DOI: 10.1016/j.jhazmat.2007.10.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2007] [Revised: 09/26/2007] [Accepted: 10/07/2007] [Indexed: 05/25/2023]
Abstract
The gasification behavior of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in fly ash by thermal treatment has been investigated to estimate gas-particle partition in flue gas. The results obtained in thermal experiments under various conditions showed that gasification of PCDD/Fs depends on air flow rate and treatment weight of fly ash as well as treatment temperature. On the other hand, the results obtained in the thermal experiments using dioxin-free fly ash revealed that during thermal treatment, the de novo synthesis, gasification, and decomposition of PCDFs proceeded at different rates. This difference in the reaction rates indicates that thermal treatment time is also a factor in determining the gas-particle partition of PCDD/Fs in fly ash. Therefore, reasonable thermal treatment conditions were established and applied to three ash samples. For all samples, PCDD/Fs started to gasify at 350 degrees C treatment, whereas 53-98% of PCDD/F homologs gasified at 400 degrees C treatment, implying that gaseous PCDD/Fs are dominant in flue gas at temperatures in the range 350-400 degrees C regardless of particle concentration.
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Affiliation(s)
- Naoki Yokohama
- Saitama-Ken Environmental Analysis and Research Association, Saitama-Shi, Saitama, Japan.
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