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Wu J, Ying Y, Ma Y, Zheng S, Lin X, Li X, Yan J. Influence of different loads on PCDD/F removal by SCR during municipal solid waste incineration. Chemosphere 2023; 338:139516. [PMID: 37454983 DOI: 10.1016/j.chemosphere.2023.139516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 07/14/2023] [Accepted: 07/14/2023] [Indexed: 07/18/2023]
Abstract
This study was conducted on a full-scale (500 t/d) municipal solid waste incinerator (MSWI), investigating the influence of different loads on the emission of polychlorinated dibenzodioxins and polychlorinated dibenzofurans (PCDD/Fs) and their removal by selective catalytic reduction (SCR) system. The total concentration of PCDD/Fs at the SCR inlet under 100% load was higher than that under 80% load. The changing loads caused different distribution characteristics of PCDD/Fs at the SCR inlet, and the dominant congeners changed from high-chlorinated PCDDs (80% load) to low-chlorinated PCDFs (100% load). Moreover, the increased load enhanced the removal efficiency of PCDD/Fs by SCR from 17.3% to 64.2%, which was influenced by the inlet PCDD/F distribution and the moisture content. The high-chlorinated PCDD/Fs with the more stable structure were more difficult to be deteriorated and the high moisture content can weaken the catalytic activity of SCR catalysts. Correlation analysis was used to study the relationship between major air pollutants and PCDD/F emissions. The results showed that HCl positively correlated with PCDD/F emission concentrations, while NOx and SO2 negatively correlated. The results of this study can provide a reference for MSWI to operate properly under variable loads.
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Affiliation(s)
- Jiayao Wu
- State Key Laboratory of Clean Energy Utilization, National Engineering Laboratory of Waste Incineration Technology and Equipment, Institute of Thermal Power Engineering of Zhejiang University, Hangzhou, 310027, Zhejiang, China
| | - Yuxuan Ying
- State Key Laboratory of Clean Energy Utilization, National Engineering Laboratory of Waste Incineration Technology and Equipment, Institute of Thermal Power Engineering of Zhejiang University, Hangzhou, 310027, Zhejiang, China
| | - Yunfeng Ma
- State Key Laboratory of Clean Energy Utilization, National Engineering Laboratory of Waste Incineration Technology and Equipment, Institute of Thermal Power Engineering of Zhejiang University, Hangzhou, 310027, Zhejiang, China
| | - Sen Zheng
- State Environmental Protection Key Laboratory of Dioxin Pollution Control, National Research Center for Environmental Analysis and Measurement, Beijing, 100029, China.
| | - Xiaoqing Lin
- State Key Laboratory of Clean Energy Utilization, National Engineering Laboratory of Waste Incineration Technology and Equipment, Institute of Thermal Power Engineering of Zhejiang University, Hangzhou, 310027, Zhejiang, China.
| | - Xiaodong Li
- State Key Laboratory of Clean Energy Utilization, National Engineering Laboratory of Waste Incineration Technology and Equipment, Institute of Thermal Power Engineering of Zhejiang University, Hangzhou, 310027, Zhejiang, China
| | - Jianhua Yan
- State Key Laboratory of Clean Energy Utilization, National Engineering Laboratory of Waste Incineration Technology and Equipment, Institute of Thermal Power Engineering of Zhejiang University, Hangzhou, 310027, Zhejiang, China
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Li C, Liu G, Qin S, Zhu T, Song J, Xu W. Emission reduction of PCDD/Fs by flue gas recirculation and activated carbon in the iron ore sintering. Environ Pollut 2023; 327:121520. [PMID: 36990339 DOI: 10.1016/j.envpol.2023.121520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 03/12/2023] [Accepted: 03/26/2023] [Indexed: 06/19/2023]
Abstract
One of the main sources of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the environment is the sintering of iron ore. Both flue gas recirculation (FGR) and activated carbon (AC), which have the impact of decreasing both PCDD/Fs and conventional pollutants (NOx, SO2, etc.), are significant technologies for the abatement of PCDD/Fs from the sintering exhaust gas. This work involved the first measurement of PCDD/Fs emissions during FGR and a thorough analysis of the impact of PCDD/Fs reduction following the coupling of FGR and AC technologies. According to the measured data, the ratio of PCDFs to PCDDs in the sintered flue gas was 6.8, indicating that during the sintering process, the PCDD/Fs were primarily produced by de novo synthesis. Further investigation revealed that FGR initially removed 60.7% of PCDD/Fs by returning it to the high temperature bed, and AC further removed 95.2% of the remaining PCDD/Fs through physical adsorption. While AC is better at removing PCDFs and can efficiently remove tetra-to octa-chlorinated homologs, FGR is more effective at removing PCDDs and has higher removal efficiency for hexa-to octa-chlorinated PCDD/Fs. Together, they complement each other with a removal rate of 98.1%. The study's findings are instructional for the process design of combining FGR and AC technologies to reduce PCDD/Fs in the sintered flue gas.
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Affiliation(s)
- Chaoqun Li
- CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing, 100190, China
| | - Guorui Liu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O.Box 2871, Beijing, 100085, China
| | - Shuai Qin
- CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing, 100190, China; China University of Petroleum, Beijing, 102249, China
| | - Tingyu Zhu
- CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing, 100190, China
| | - Jianfei Song
- China University of Petroleum, Beijing, 102249, China
| | - Wenqing Xu
- CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing, 100190, China.
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Lu JW, Xie Y, Xie B, Li Z, Huang Z, Zhang D, Hai J. Buffering effect of the economizer against PCDD/Fs in flue gas from solid waste incineration plants. Waste Manag 2023; 167:103-112. [PMID: 37245393 DOI: 10.1016/j.wasman.2023.05.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 05/06/2023] [Accepted: 05/21/2023] [Indexed: 05/30/2023]
Abstract
The emission of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) from solid waste incineration is always a crucial concern for the society. Less attention has been paid to differentiate its formation and migration in the low temperature range of economizer, leading to a fuzzy understanding on the control of PCDD/Fs before flue gas cleaning. This study first reveals the buffering effect against PCDD/Fs in the economizer, which is contrary to the well-known memory effect, and first recognizes the intrinsic mechanism by 36 sets of full-scale experimental data under three typical operating conditions. Results indicated that the buffering effect, which includes interception and releasing, could remove averagely 82.9 % of PCDD/Fs in flue gas and reconcile PCDD/Fs profiles. The interception effect is dominant and in compliance with the condensation law. The low temperature range of economizer is exactly suitable for the condensation of lowly chlorinated congeners, which condense behind highly chlorinated ones. The releasing effect was non-staple but stimulated by the sudden change of operating condition, proving that PCDD/Fs formation rarely exists in the economizer. The buffering effect is mainly controlled by the physical migration of PCDD/Fs among different phases. The condensation of PCDD/Fs leads to their migration from vapor phase to aerosol and solid phases during flue gas cooling in the economizer. There is no need for excessive anxiety about PCDD/Fs formation in the economizer because it rarely exists. Intensifying the condensation process of PCDD/Fs in the economizer can help relieve the pressure of end-of-pipe measures for PCDD/Fs control.
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Affiliation(s)
- Jia-Wei Lu
- South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510655, China; Guangdong Province Engineering Laboratory for Solid Waste Incineration 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 Incineration Technology and Equipment, Guangzhou 510330, China
| | - Bing Xie
- South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510655, China; Guangdong Province Engineering Laboratory for Solid Waste Incineration Technology and Equipment, Guangzhou 510330, China.
| | - Zhihong Li
- Chongqing Sanfeng Environment Group Co., Ltd, Chongqing 400084, China
| | - Zhengpeng Huang
- Chongqing Sanfeng Environment Group Co., Ltd, Chongqing 400084, China
| | - Dongfeng Zhang
- Chongqing Sanfeng Environment Group Co., Ltd, Chongqing 400084, China
| | - Jing Hai
- South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510655, China; Guangdong Province Engineering Laboratory for Solid Waste Incineration Technology and Equipment, Guangzhou 510330, China.
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Wang X, Lv J, Ying Y, Ma Y, Wu A, Lin X, Cao A, Li X, Yan J. A new insight into the CaO-induced inhibition pathways on PCDD/F formation: Metal passivation, dechlorination and hydroxide substitution. Sci Total Environ 2023; 885:163782. [PMID: 37149162 DOI: 10.1016/j.scitotenv.2023.163782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 04/07/2023] [Accepted: 04/23/2023] [Indexed: 05/08/2023]
Abstract
Ca-based inhibitors (especially CaO) for PCDD/F (polychlorinated dibenzo-p-dioxin and dibenzofuran) formation are considered as economic inhibitors with low toxicity and strong adsorption of acidic gases (e.g., HCl, Cl2, and SOx), whereas the insight understanding of its inhibition mechanisms is scarcely explored. Herein, CaO was used to inhibit the de novo reaction for PCDD/F formation (250-450 °C). The evolution of key elements (C, Cl, Cu, and Ca) combined with theoretical calculations was systematically investigated. The concentrations and distribution of PCDD/Fs demonstrated the significant inhibition effect of CaO on I-TEQ (international toxic equivalency) concentrations of PCDD/Fs (inhibition efficiencies: > 90 %) and hepta~octa chlorinated congeners (inhibition efficiencies: 51.5-99.8 %). And the conditions (5-10 % CaO, 350 °C) were supposed to be the preferred conditions applied in real MSWIs (municipal solid waste incinerators). CaO significantly suppressed the chlorination of carbon matrix (superficial organic Cl (CCl) reduced from 16.5 % to 6.5-11.3 %) and the formation of unsaturated hydrocarbons or aromatic carbon (superficial CC decreased from 6.7 % to 1.3-2.1 %). Also, CaO promoted the dechlorination of Cu-based catalysts and Cl solidification (e.g., conversion of CuCl2 to CuO, and formation of CaCl2). The dechlorination phenomenon was validated by the dechlorination of highly chlorinated PCDD/F-congeners (via DD/DF chlorination pathways). Density functional theory calculations revealed that CaO facilitated the substitution of Cl by -OH on the benzene ring to inhibit the polycondensation of the chlorobenzene and chlorophenol (Gibbs free energy reduced from +74.83 to -36.62 and - 148.88 kJ/mol), which also indicates the dechlorination effect of CaO on de novo synthesis.
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Affiliation(s)
- Xiaoxiao Wang
- State Key Laboratory for Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou 310027, China
| | - Jiabao Lv
- State Key Laboratory for Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou 310027, China
| | - Yuxuan Ying
- 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
| | - Angjian Wu
- State Key Laboratory for Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou 310027, China; Jiaxing Research Institute, Zhejiang University, 314031, PR China
| | - Xiaoqing Lin
- State Key Laboratory for Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou 310027, China; Jiaxing Research Institute, Zhejiang University, 314031, PR China.
| | - Ang Cao
- Department of Physics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Xiaodong Li
- State Key Laboratory for Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou 310027, China; Jiaxing Research Institute, Zhejiang University, 314031, PR China
| | - Jianhua Yan
- State Key Laboratory for Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou 310027, China
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Chen T, Xiang W, Wu A, Lin X, Chen Z, Li X, Yan J. Suppression on PCDD/Fs formation by a novel inhibition system consisting of phosphorous-based compounds coupled with a chlorine-deactivation material. Waste Manag 2023; 156:33-43. [PMID: 36436406 DOI: 10.1016/j.wasman.2022.11.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 11/05/2022] [Accepted: 11/17/2022] [Indexed: 06/16/2023]
Abstract
The SN-containing inhibitors are effective for suppressing the formation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the post-combustion zone of municipal solid waste incineration systems, but the industrial application of the SN-containing inhibitors is restricted by the high cost and the generation of corrosive by-products (e.g., SOx). To develop cost-effective and environmentally friendly inhibitors, a new inhibition system consisting of P-based compounds (i.e., NH4H2PO4 (ADP) and KH2PO4 (PDP)) and a chlorine-deactivation material (CaO) was proposed in this study. Also, the performance of this inhibition system in terms of suppressing PCDD/Fs formation was evaluated in an experimental system which simulated PCDD/Fs generation in the post-combustion zone. Generally, the formation of PCDD/Fs was effectively suppressed by over 95 % by the mixed inhibitors (ADP/CaO and PDP/CaO) and the individual inhibitor of ADP. Based on the observation on PCDD/F-fingerprints and the chemical speciation of Cl and Cu, the mechanisms of inhibitors were identified as: (i) passivating metal catalyst by converting the speciation of Cu from chlorides and Cu2+ with high reactivities to phosphates, oxides, and Cu+ with low reactivities, and (ii) deactivating Cl by CaO to prevent the formation of organic Cl which was critical for PCDD/Fs formation. In addition, both mechanisms were supported by (i) the better performance of inhibitors on suppressing the PCDD/F-congeners formed via de novo pathway than congeners synthesized from chlorophenols and (ii) lower degrees of chlorination of PCDD/Fs for reaction systems with CaO involved than other systems.
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Affiliation(s)
- Tong Chen
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou 310027, China
| | - Weican Xiang
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou 310027, China
| | - Angjian Wu
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou 310027, China
| | - Xiaoqing Lin
- State Key Laboratory of 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 37235, USA.
| | - Xiaodong Li
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou 310027, China
| | - Jianhua Yan
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou 310027, China
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Ma Y, Lai J, Wu J, Zhang H, Yan J, Li X, Lin X. Efficient synergistic catalysis of chlorinated aromatic hydrocarbons and NO x over novel low-temperature catalysts: Nano-TiO 2 modification and interaction mechanism. Chemosphere 2023; 315:137640. [PMID: 36584823 DOI: 10.1016/j.chemosphere.2022.137640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 12/12/2022] [Accepted: 12/21/2022] [Indexed: 06/17/2023]
Abstract
For efficient and synergistic elimination of chlorinated aromatic hydrocarbons (e.g., dioxins and chlorobenzenes) and NOx at low temperatures, a novel VOx-CeOx-WOx/TiO2 catalyst was systemically studied, involving the nano-TiO2 modification and the interaction mechanism between 1,2-dichlorobenzen (1,2-DCB) catalytic oxidation (DCBCO) and NH3-SCR. The VOx-CeOx-WOx/TiO2 performed excellent oxygen storage/release capacity (OSRC) and desirable 1,2-DCB conversion efficiency (95.1-97.4%) at 160-200 ℃ via M‒K and L‒H mechanism. The nano-TiO2 modification slightly impaired the 1,2-DCB oxidation to 93.6-96.2% owing to the reduced surface area and Brønsted acidity, while it distinctly enhanced NO conversion and lowered the T50 (from 162 to 112 ℃) and T90 (from 232 to 205 ℃) by improving catalyst reducibility. Based on further synergistic catalysis evaluation and in-situ DRIFT analysis, NO enhanced the 1,2-DCB conversion and complete oxidation capacity of VOx-CeOx-WOx/TiO2 by promoting active oxygen (O2-, O-, O2-) generation and improving 1,2-DCB chemosorption and subsequent oxidation. In detail, the produced HCl and H2O improved the catalyst acidity and promoted the formation of HONO and HNO3. Moreover, their generation not only facilitated the chemisorption of NH3 but also participated in the NH3-SCR via L‒H mechanism. The ensuing problem was the competitive chemisorption among 1,2-DCB, NH3, and their subsequent intermediates. As a result, NH3 had distinct advantages in competing for acid sites and active oxygen species, especially at the higher temperature, resulting in the improved NO conversion with elevated reaction temperature but the reduced 1,2-DCB conversion. The results provided essential basics for developing new catalysts to synergistically control the emission of chloroaromatic organics and NOx at low temperature.
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Affiliation(s)
- Yunfeng Ma
- State Key Laboratory for Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Jianwen Lai
- State Key Laboratory for Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Jiayao Wu
- State Key Laboratory for Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Hao Zhang
- 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
| | - Xiaodong Li
- State Key Laboratory for Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Xiaoqing Lin
- State Key Laboratory for Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China.
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Lin X, Wang X, Ying Y, Wu A, Chen Z, Wang L, Yu H, Zhang H, Ruan A, Li X, Yan J. Formation pathways, gas-solid partitioning, and reaction kinetics of PCDD/Fs associated with baghouse filters operated at high temperatures: A case study. Sci Total Environ 2023; 857:159551. [PMID: 36265614 DOI: 10.1016/j.scitotenv.2022.159551] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Revised: 09/29/2022] [Accepted: 10/14/2022] [Indexed: 06/16/2023]
Abstract
The application of the 3T method during combustion (i.e., a Temperature > 850 °C, a residence Time > 2 s, and sufficient Turbulence) can lead to elevated operating temperature in the baghouse filter for the municipal solid waste incineration (MSWI) systems without sufficient heat exchange capacity, which is potentially detrimental to the emission control of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). Herein, a field study focusing on the distribution and variation of PCDD/Fs in gaseous and solid phases in a baghouse filter with high operating temperature (225-230 °C) was carried out. The concentration of PCDD/Fs in gases at the outlet of the baghouse filter was around 1 order of magnitude higher than that in inlet gases (i.e., noticeable memory effect of PCDD/Fs), because of the significant PCDD/Fs formation in filter fly ash (primarily contributed by the precursor pathway) followed by PCDD/Fs desorption. In addition, the mechanisms and factors resulting in the memory effect of PCDD/Fs were identified based on a laboratory study that carefully investigated the formation and desorption of PCDD/Fs at potential operating temperatures of baghouse filters (i.e., 180, 200, and 225 °C). The temperature was identified as the key factor inducing the memory effect of PCDD/Fs, because: i) PCDD/Fs memory effect was not observed for baghouse filters with low operating temperatures of ~150 °C in previous studies; ii) both the formation and desorption of PCDD/Fs were noticeably favored by rising temperature from 180 to 225 °C; iii) increasing temperature appeared to facilitate the transformation from inorganic Cl to organic Cl and the conversion from aliphatic carbon to aromatic carbon or unsaturated hydrocarbons, both of which were favorable to PCDD/Fs formation; and iv) the release rate of PCDD/Fs from fly ash was exponentially dependent on temperature based on the modeling results of reaction kinetics.
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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
| | - Xiaoxiao Wang
- State Key Laboratory for Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou 310027, China
| | - Yuxuan Ying
- State Key Laboratory for Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou 310027, China
| | - Angjian Wu
- 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 37235, USA.
| | - Lei Wang
- State Key Laboratory for Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou 310027, China
| | - Hong Yu
- State Key Laboratory for Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou 310027, China
| | - Hao Zhang
- State Key Laboratory for Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou 310027, China
| | - Aizhong Ruan
- Zhejiang Shengyuan Environmental Testing Technology Co., Ltd., 311899 Shaoxing, China
| | - Xiaodong Li
- 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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Ying Y, Wang X, Song W, Ma Y, Yu H, Lin X, Lu S, Li X, Huang W, Zhong L. Assessment of PCDD/Fs Emission during Industrial-Organic-Solid-Waste Incineration Process in a Fluidized-Bed Incinerator. Processes (Basel) 2023; 11:251. [DOI: 10.3390/pr11010251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
This study was conducted in a fluidized-bed incineration plant, evaluating the formation, emission and flux of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) from industrial-organic-solid-waste (IW) incineration. The results revealed that both the total (or I-TEQ) concentrations of toxic and 136 total PCDD/Fs in flue gas (FG), fly ash (FA) and bottom ash (BA)were ramped up to a higher level than those during municipal-solid-waste (MSW) incineration. A possible explanation was the chlorine (Cl) content of IW. However, the emitted PCDD/Fs in FG (FA/BA) still fulfilled the criteria. Subsequently, similar distribution patterns of PCDD/F isomers were observed in subsystems, indicating a unified formation-pathway. De novo synthesis was detected as the dominant formation-pathway of PCDD/Fs, while high-temperature and precursor syntheses were excluded. DD/DF chlorination formed PCDD/Fs to some extent. Furthermore, the mass flow chart indicated that PCDD/Fs output in primary FG was significantly strengthened (>1000 times) by de novo synthesis, from 1.25 μg I-TEQ/h to 1.67 mg I-TEQ/h. With effective cleaning by APCS, 99.6% of PCDD/Fs in FG were purified. PCDD/Fs in the gas phase were finally emitted at a discharge rate of 7.25 μg I-TEQ/h. However, accumulated FA took most PCDD/Fs into the environment (>99%), reaching 3.56 mg I-TEQ/h.
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Ying Y, Xu L, Lin X, Zhang H, Li X, Lu S, Cao Y, Long J. Influence of different kinds of incinerators on PCDD/Fs: a case study of emission and formation pathway. Environ Sci Pollut Res Int 2023; 30:5903-5916. [PMID: 35982393 DOI: 10.1007/s11356-022-22437-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Accepted: 08/03/2022] [Indexed: 06/15/2023]
Abstract
Few studies focused on the emission of polychlorinated-ρ-dibenzodioxins and dibenzofurans (PCDD/F) from different kinds of waste incinerators. This study was conducted in a full-scale MSW incineration plant to investigate the influence of different incinerator types on PCDD/F. Experimental results indicated that the 2,3,7,8-PCDD/F concentration in the inlet gas of the air pollution control system (APCS) in the studied fluidized bed was higher (2.03 ng I-TEQ/Nm3) than that of the grate (0.77 ng I-TEQ/Nm3). But gas in the outlet of APCS from both incinerators had an approximate concentration, lower than the Chinese emission limit of 0.1 ng I-TEQ/Nm3. Similar distribution patterns were observed for 2,3,7,8-PCDD/Fs, as well as 136 PCDD/F congeners. Specifically, OCDD and 1,2,3,4,6,7,8-HpCDD were major isomer constituents for 2,3,7,8-PCDD/F isomers. In terms of formation pathways, a similar formation mechanism was observed based on fingerprint characteristics of 136 PCDD/F congeners. De novo synthesis was the dominating formation pathway for both incinerators. Meanwhile, DD/DF chlorination was another contributor to PCDD/F formation, which in the fluidized bed was higher. In addition, little correlation (0.009 < R2 < 0.533) between conventional pollutants (HCl, CO, PM) and PCDD/Fs was found, suggesting little high-temperature synthesis observed and verifying the dominance of de novo synthesis.
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Affiliation(s)
- Yuxuan Ying
- State Key Laboratory of Clean Energy Utilization, Institute of Thermal Power Engineering of Zhejiang University, Hangzhou, 310027, China
| | - Liang Xu
- Tianjin Eco-Environmental Monitoring Center, Tianjin Ecology and Environment Bureau, Tianjin, 300192, China
| | - Xiaoqing Lin
- State Key Laboratory of Clean Energy Utilization, Institute of Thermal Power Engineering of Zhejiang University, Hangzhou, 310027, China.
| | - Hao Zhang
- State Key Laboratory of Clean Energy Utilization, Institute of Thermal Power Engineering of Zhejiang University, Hangzhou, 310027, China
| | - Xiaodong Li
- State Key Laboratory of Clean Energy Utilization, Institute of Thermal Power Engineering of Zhejiang University, Hangzhou, 310027, China
| | - Shengyong Lu
- State Key Laboratory of Clean Energy Utilization, Institute of Thermal Power Engineering of Zhejiang University, Hangzhou, 310027, China
| | - Yang Cao
- Shanghai SUS Environment Co., Ltd., Shanghai, 201703, China
| | - Jisheng Long
- Shanghai SUS Environment Co., Ltd., Shanghai, 201703, China
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Wu D, Xu F, Liu X, Li C, Chu X, Fan G, Xu H. Adsorption of CO, NO, and SO2 gases on pristine and single Ni3 cluster doped arsenene monolayer for its potential application as sensor or adsorbent by density functional theory study. COMPUT THEOR CHEM 2022. [DOI: 10.1016/j.comptc.2022.113871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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11
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Lin X, Ma Y, Chen T, Wang L, Takaoka M, Pan S, Zhang H, Wu A, Li X, Yan J. PCDD/Fs and heavy metals in the vicinity of landfill used for MSWI fly ash disposal: Pollutant distribution and environmental impact assessment. Environ Pollut 2022; 312:120083. [PMID: 36064061 DOI: 10.1016/j.envpol.2022.120083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 07/19/2022] [Accepted: 08/28/2022] [Indexed: 06/15/2023]
Abstract
This study focused on the syngenetic control of polychlorinated-ρ-dibenzodioxins and dibenzofurans (PCDD/Fs) and heavy metals by field stabilization/solidification (S/S) treatment for municipal solid waste incineration fly ash (MSWIFA) and multi-step leachate treatment. Modified European Community Bureau of Reference (BCR) speciation analysis and risk assessment code (RAC) revealed the medium environment risk of Cd and Mn, indicating the necessity of S/S treatment for MSWIFA. S/S treatment significantly declined the mass/toxic concentrations of PCDD/Fs (i.e., from 7.21 to 4.25 μg/kg; from 0.32 to 0.20 μg I-TEQ/kg) and heavy metals in MSWIFA due to chemical fixation and dilution effect. The S/S mechanism of sodium dimethyldithiocarbamate (SDD) and cement was decreasing heavy metals in the mild acid-soluble fraction to reduce their mobility and bioavailability. Oxidation treatment of leachate reduced the PCDD/F concentration from 49.10 to 28.71 pg/L (i.e., from 1.60 to 0.98 pg I-TEQ/L) by suspension absorption or NaClO oxidation decomposition, whereas a so-called "memory effect" phenomena in the subsequent procedures (adsorption, press filtration, flocculating settling, slurry separation, and carbon filtration) increased it back to 38.60 pg/L (1.66 pg I-TEQ/L). Moreover, the multi-step leachate treatment also effectively reduced the concentrations of heavy metals to 1-4 orders of magnitude lower than the national emission standards. Furthermore, the PCDD/Fs and heavy metals in other multiple media (soil, landfill leachate, groundwater, and river water) and their spatial distribution characteristics site were also investigated. No evidence showed any influence of the landfill on the surrounding liquid media. The slightly higher concentration of PCDD/Fs in the soil samples was ascribed to other waste management processes (transportation and unloading) or other local source (hazardous incineration plant). Therefore, proper management of landfills and leachate has a negligible effect on the surrounding environment.
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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
| | - Tong Chen
- State Key Laboratory for Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Lei Wang
- State Key Laboratory for Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Masaki Takaoka
- Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Kyoto, 6158510, Japan
| | - Shuping Pan
- Zhejiang Ecological and Environment Monitoring Center, Hangzhou, 310012, China.
| | - Hao Zhang
- State Key Laboratory for Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Angjian Wu
- State Key Laboratory for Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Xiaodong Li
- 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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12
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Lin SL, Tang W, Wu JL, Lee YY, Wang CL, Chen WH. Particulate PCDD/F size distribution and potential deposition in respiratory system from a hazardous waste thermal treatment process. Environ Res 2022; 214:113806. [PMID: 35863447 DOI: 10.1016/j.envres.2022.113806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 06/21/2022] [Accepted: 06/29/2022] [Indexed: 06/15/2023]
Abstract
The particulate polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) of various sizes produced from the waste incinerators might have different toxicities, deposition characteristics, and potential health effects in the respiratory system, and their total toxicity equivalent (TEQ) concentration has been strictly regulated in recent years. There is a knowledge gap on the effects of air pollution control devices on particle size distributions (PSDs) of PCDD/Fs and their TEQ deposition. A hazardous waste thermal treatment plant equipped with an advanced scrubber, a cyclone demister, and activated carbon adsorption coupled with a baghouse filtration was investigated in this study. An 8-stage impactor was used to collect the particle distribution of PM10 and bounded PCDD/Fs from the gas stream at four sampling points located before and after each control unit. A "TEQDE" index is defined for the toxicity deposition of PM10-PCDD/F in the respiratory system. The advanced scrubbers significantly reduced the PM10-PCDD/F levels, especially for those with sizes ≥0.6 and ≤ 0.4 μm. Additionally, the cyclone also showed a better performance than the general dry gas treatment but had an efficiency drop with 1.5-4 μm particles. The PM10-PCDD/F loads in the final adsorption-filtration unit were eased and effectively removed the PM10-PCDD/Fs to sizes ≤0.5 or≥1.5 μm. The total TEQDE was 0.00052 ng WHO-TEQ Nm-3 and had a peak level of 0.000157 ng WHO-TEQ Nm-3 at 1.2 μm. PSDs were more sensitive to the PSDs of PM mass at high PM levels but strongly correlated with the PSDs of "PM10-PCDD/Fs/PM10" at low PM10 loads. Consequently, the advanced control system could effectively remove the PM10-PCDD/Fs and might extend the adsorption-filtration lifetime. However, the PM10-PCDD/Fs ≤ 0.4 μm had a higher TEQ deposition rate and should be further considered in emissions and ambient air quality evaluations.
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Affiliation(s)
- Sheng-Lun Lin
- School of Mechanical Engineering, Beijing Institute of Technology, Beijing, 100081, China
| | - Wei Tang
- School of Mechanical Engineering, Beijing Institute of Technology, Beijing, 100081, China
| | - Jhong-Lin Wu
- Environmental Resource and Management Research Center, National Cheng Kung University, Tainan, 70101, Taiwan
| | - Yen-Yi Lee
- Center for Environmental Toxin and Emerging-contaminant Research, Cheng Shiu University, Kaohsiung, 83347, Taiwan; Department of Food and Beverage Management, Cheng Shiu University, Kaohsiung, 83347, Taiwan
| | - Chih-Lung Wang
- Center for Environmental Toxin and Emerging-contaminant Research, Cheng Shiu University, Kaohsiung, 83347, Taiwan; Department of Civil Engineering and Geomatics, Cheng Shiu University, Kaohsiung, 83347, Taiwan
| | - Wei-Hsin Chen
- Department of Aeronautics and Astronautics, National Cheng Kung University, Tainan, 70101, Taiwan; Research Center for Smart Sustainable Circular Economy, Tunghai University, Taichung, 407224, Taiwan; Department of Mechanical Engineering, National Chin-Yi University of Technology, Taichung, 411030, Taiwan.
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Song Z, Peng Y, Zhao X, Liu H, Gao C, Si W, Li J. Roles of Ru on the V 2O 5–WO 3/TiO 2 Catalyst for the Simultaneous Purification of NO x and Chlorobenzene: A Dechlorination Promoter and a Redox Inductor. ACS Catal 2022. [DOI: 10.1021/acscatal.2c03782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Zijian Song
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Yue Peng
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Xiaoguang Zhao
- Sinopec Research Institute of Petroleum Processing, Beijing 100083, China
| | - Hao Liu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Chuan Gao
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Wenzhe Si
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Junhua Li
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
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Wei J, Li H, Liu J. Curbing dioxin emissions from municipal solid waste incineration: China's action and global share. J Hazard Mater 2022; 435:129076. [PMID: 35650750 DOI: 10.1016/j.jhazmat.2022.129076] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 03/30/2022] [Accepted: 05/02/2022] [Indexed: 06/15/2023]
Abstract
China generates the world's second-largest amount of municipal solid waste (MSW) and incinerates the largest quantity of MSW. However, data on the latest dioxin emissions from MSW incineration (MSWI) and the related global share were lacking. In the context of MSW classification, distinguishing the long-term MSW generation and incineration quantity, and dioxin emissions was necessary for macro-control and policy-making by the Chinese Government. By considering population size and GDP per capita, China's MSW generation toward 2050 was projected based on Monte Carlo simulation. Moreover, dioxin emission factors were also assumed based on the diffusion rate of four grades of air pollution control devices (APCDs). Finally, we show that the quantity of China's MSW generation in 2050 will be 363.50 million tonnes (Mt) with 341.06-382.45 Mt of 75% certainty. China's dioxin emissions from MSWI were approximately 15.46 g I-TEQ in 2019, which accounted for 26.1% of total emissions from global MSWI. We discuss dioxin emission reduction scenarios depending on MSW diversion and APCD upgrades. China's dioxin emissions will be 70.38 g I-TEQ for the business-as-usual scenario, and the dioxin emissions will be 9.29 g I-TEQ (within the range of 8.88-9.64 g I-TEQ) for the optimal scenario in 2050. Moreover, in 2050, the APCD diffusion rate will account for 98.8% of the sensitivity of dioxin emissions from China's MSWI. According to the assumed scenarios, there is a dioxin emission reduction potential of 18.6% and 86.8% in 2050 by MSW diversion alone and maximum APCD upgrades combined with food waste diversion, respectively.
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Affiliation(s)
- Junxiao Wei
- Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
| | - Huan Li
- Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China.
| | - Jianguo Liu
- Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; School of Environment, Tsinghua University, Beijing 100084, China.
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15
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Du J, Sun L. A benefit allocation model for the joint prevention and control of air pollution in China: In view of environmental justice. J Environ Manage 2022; 315:115132. [PMID: 35489189 DOI: 10.1016/j.jenvman.2022.115132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 04/12/2022] [Accepted: 04/19/2022] [Indexed: 06/14/2023]
Abstract
The benefit allocation of fair and justice is an inevitable guarantee for the long-term operation of the joint prevention and control of air pollution (JPCAP). The ignorance of interest demands of various governance subjects in the existing benefit allocation mechanism results in the widespread "free rider" behavior in the joint control and unsatisfactory effects of JPCAP. Given this, it is imperative to build a reasonable benefit allocation model. The innovation of this paper is proposing a benefit allocation model of JPCAP to achieve the symmetry between control costs and benefits based on environmental justice. The control objectives and total benefits of JPCAP are calculated through the adjustment of optimal removal rates. The interest demands of various control subjects and benefit compensation scheme are clarified by adopting an improved Shapley method, which comprehensively considers factors affecting environmental justice. An empirical analysis is conducted on SO2 governance in Beijing-Tianjin-Hebei (BTH) and its surrounding areas. The results show that the benefit allocation model based on environmental justice can not only accurately evaluate the benefits of joint control, but also effectively achieve the symmetry between control costs and benefits. This study provides a scientific and reasonable theoretical basis for the benefit allocation of SO2 control and can be extended to the researches and practices of other air pollutants control.
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Affiliation(s)
- Juan Du
- School of Economics and Management, Hebei University of Technology, Tianjin, 300401, Tianjin Province, China.
| | - Liwen Sun
- School of Economics and Management, Hebei University of Technology, Tianjin, 300401, Tianjin Province, China.
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16
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Xiong S, Yaqi P, Shengyong L, Chen K, Li X, Kefa C. PCDD/Fs from a large-scale municipal solid waste incinerator under transient operations: Insight formation pathways and optimal reduction strategies. J Environ Manage 2022; 314:114878. [PMID: 35447442 DOI: 10.1016/j.jenvman.2022.114878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 02/26/2022] [Accepted: 03/07/2022] [Indexed: 06/14/2023]
Abstract
Polychlorinated dibenzo-p-dioxin and dibenzofurans (PCDD/Fs) emissions from the transient operation of municipal solid waste incinerators can reach up to 690 ng/Nm3, as measured in this study. To control the extreme emissions to meet the national standard, the formation pathways of PCDD/F were investigated under transient operations (cold start-up, hot start-up, and after start-up) and normal operations. Compared with normal operations, transient operations facilitate the formation of low-chlorinated congeners rather than highly chlorinated congeners. Statistically, for transient operations, strong correlations were found among tetrachlorodibenzo-p-dioxin or tetrachlorodibenzofuran isomers. An abundant carbon matrix is an important carbon source for PCDD formation. Moreover, the comprehensive study revealed that the oxidation of deposited soot is the main source of PCDD/F emissions, relative to de novo synthesis, chlorobenzene-route synthesis, chlorophenol-route synthesis, and chlorination of dibenzo-p-dioxin/dibenzofuran. In addition, the optimal start-up procedure was constructed by analyzing main formation pathways and operating conditions. The relationship between the international toxic quantity (I-TEQ) values (CI-TEQ) and the reaction time can be assigned as CI-TEQ = 11.72t-0.65 (R2 = 0.97) for the circulating fluidized bed. The relationship of CI-TEQ = 4.61t-0.59 (R2 = 0.85) was also proven on the dataset with a grate furnace. Then, the optimal feeding rate of activated carbon was further proposed by the relationship between the reaction time and I-TEQ, and the semi-empirical equation for PCDD/Fs adsorption. Finally, the PCDD/Fs emissions can be reduced to 0.1 ng I-TEQ/Nm3 under transient operations according to the time since start-up.
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Affiliation(s)
- Shijian Xiong
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, 310027, PR China
| | - Peng Yaqi
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, 310027, PR China
| | - Lu Shengyong
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, 310027, PR China.
| | - Ken Chen
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, 310027, PR China
| | - Xiaodong Li
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, 310027, PR China
| | - Cen Kefa
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, 310027, PR China
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17
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Wei J, Li H, Liu J. Fate of dioxins in a municipal solid waste incinerator with state-of-the-art air pollution control devices in China. Environ Pollut 2021; 289:117798. [PMID: 34340177 DOI: 10.1016/j.envpol.2021.117798] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 04/19/2021] [Accepted: 07/14/2021] [Indexed: 06/13/2023]
Abstract
The variation of municipal solid waste (MSW) components and the improvement of incinerators have an obvious effect on dioxin emissions. However, there is a knowledge gap on dioxin distribution characteristics following China's implementation of MSW classification. To reveal the fate of dioxins under ultra-low emission standards in leading cities in China, a systematic investigation was carried out in a typical modern MSW incinerator in Shenzhen, China. The dioxin mass balance was built using improved models, which included expanded samples, e.g., the leachate, the raw gas and raw ash from boiler, and the chemicals and residuals from air pollution control devices (APCDs). The results indicated a positive dioxin balance of 0.88 μg I-TEQ/t MSW according to the conventional method containing fly ash, bottom ash, and stack gas. In the new model revealing dioxin characteristics after APCDs, a higher value of 0.89 μg I-TEQ/t MSW was found due to the leachate, slaked lime, and activated carbon-containing dioxins. The distribution of dioxins in output samples of fly ash, bottom ash, stack gas, and leachate were 149.0 %, 41.8 %, 1.6 %, and 0.6 % of MSW, respectively. For incineration itself, the balance was 0.85 μg I-TEQ/t MSW, which indicated the possible release owing to the "memory effect" for the other two methods. This study provided new insight for the accurate estimation of dioxin emissions and a typical case report of MSW incineration with ultra-low dioxin emissions.
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Affiliation(s)
- Junxiao Wei
- Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China
| | - Huan Li
- Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China
| | - Jianguo Liu
- Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China; School of Environment, Tsinghua University, Beijing, 100084, China.
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18
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Xiong S, Peng Y, Lu S, Shang F, Li X, Yan J, Cen K. Generalized prediction and optimal operating parameters of PCDD/F emissions by explainable Bayesian support vector regression. Waste Manag 2021; 135:437-447. [PMID: 34619625 DOI: 10.1016/j.wasman.2021.09.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 08/23/2021] [Accepted: 09/19/2021] [Indexed: 06/13/2023]
Abstract
The current derived models for predicting polychlorinated dibenzo-p-dioxins and -furans (PCDD/F) emissions from incineration can only be applied to a specific incinerator due to high deviation or systematic errors. And the models fail to provide quantized guidance for the operation of full-scale municipal solid waste incinerators. To address the problem, explainable Bayesian support vector regression (E-BSVR) has been established to generalized predict and maximumly reduce the PCDD/F emissions. First, forty-two PCDD/F samples were determined from a whole year experiment in a full-scale incinerator. Meanwhile, 1,2,4-trichlorobenzene(1,2,4-TrCBz), carbon monoxide, sulfur dioxide, oxynitride, particulate matter, fluoride, and hydrogen chloride were measured, as input features. Second, after box-cox transformation normalization, and hyperparameters tuning, the R-Squared and root mean square error (RMSE) of the proposed method are 0.983 and 0.044, exhibiting high accuracy. The high accuracy (R-Squared = 0.992) and generalization are also proven on the dataset with high PCDD/F emissions. Then, the performances of BSVR are compared with kernel ridge regression, multiple linear regression, and unary linear regression, indicating afar smaller RMSE of BSVR. Finally, the optimal operating parameters are calculated through local interpretable model-agnostic explanations and the partial dependence plot. Results indicate that reducing the content of organic chlorine in municipal solid waste and inhibiting the deacon reaction are important methods for reducing PCDD/F emissions. The optimal operating parameters for the maximal reduction of PCDD/F emissions are 1,2,4-TrCBz < 0.098 ug/m3, fluoride > 0.452 mg/m3. As a whole, the E-BSVR method can be used as a reliable and accurate approach for the prediction and reduction of PCDD/F emissions.
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Affiliation(s)
- Shijian Xiong
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, PR China
| | - Yaqi Peng
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, PR China
| | - Shengyong Lu
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, PR China.
| | - Fanjie Shang
- Zhejiang Fuchunjiang Environmental Technology Research Co., Ltd., Hangzhou 311401, PR China
| | - Xiaodong Li
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, PR China
| | - Jianhua Yan
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, PR China
| | - Kefa Cen
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, PR China
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Wei J, Li H, Liu J. Phase distribution of PCDD/Fs in flue gas from municipal solid waste incinerator with ultra-low emission control in China. Chemosphere 2021; 276:130166. [PMID: 33714149 DOI: 10.1016/j.chemosphere.2021.130166] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 02/26/2021] [Accepted: 02/28/2021] [Indexed: 06/12/2023]
Abstract
Polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) are the key pollutants of municipal solid waste incineration (MSWI). In this study, the characteristics of 17 toxic 2,3,7,8-substituted congeners in flue gas along six air pollution control devices (APCDs) were investigated in a 400 t/d moving grate furnace located in a typical megacity of Shenzhen, China. The phase distribution and removal efficiency of the different APCDs were analyzed, especially the effect of the selective catalytic reduction (SCR) device. The results showed that PCDD/F TEQs were 59.5%, 67.1%, and 72.5% partitioned into the gas phase (XAD-2 and condensed water) at the economizer outlet, fabric filter outlet, and stack, respectively. Furthermore, the three-year-old catalyst in the SCR tended to remove PCDDs, especially those in the solid phase (filter thimble). More importantly, the PCDF TEQs at the SCR inlet and outlet were 1.045 × 10-3 and 1.568 × 10-3 ng I-TEQ/Nm3, respectively, which meant that the SCR might be ineffective for PCDF TEQ removal. A continuous chlorination of lower chlorinated PCDD/Fs increased the ratio of PCDFs and PCDDs from 0.73 at the SCR inlet to 1.76 at the SCR outlet. This work indicated the asynchronized inefficient removal of PCDD/Fs and nitrogen oxide for this three-year-old catalyst. The obtained results provide suggestions for the entire process of curbing PCDD/F emissions and obtaining ultra-low emission from MSWI.
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Affiliation(s)
- Junxiao Wei
- Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China
| | - Huan Li
- Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China.
| | - Jianguo Liu
- Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China; School of Environment, Tsinghua University, Beijing, 100084, China.
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Cheruiyot NK, Yang HH, Wang LC, Lin CC. Feasible and effective control strategies on extreme emissions of chlorinated persistent organic pollutants during the start-up processes of municipal solid waste incinerators. Environ Pollut 2020; 267:115469. [PMID: 32866860 DOI: 10.1016/j.envpol.2020.115469] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 07/28/2020] [Accepted: 08/17/2020] [Indexed: 06/11/2023]
Abstract
A typical two-day start-up of municipal solid waste incinerators (MSWIs) can yield polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/F) and polychlorinated biphenyl (PCB) emission quantities around 10 times higher than those from an entire year of normal operations, as measured in this study. Thus, we tested specific control strategies for inhibiting the formation of chlorinated persistent organic pollutants (Cl-POPs), namely, extensively cleaning the ash accumulated beneath the furnace bed of the combustion chamber and deposited on the walls of the superheater and economizer and shortening the residence time of the flue gas in the optimal temperature window for Cl-POP formation. Also, we advanced the injection times of the activated carbon and lime slurry to lower Cl-POP emissions during start-up. Our findings show that these strategies were highly effective and reduced the Cl-POP emissions by > 98%, most of which (96.4-98.2%) was attributable to inhibiting formation. In summary, the proposed control strategies require no modifications to existing air pollution control devices, have little influence on operational cost, and are effective and feasible for the majority of MSWIs.
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Affiliation(s)
- Nicholas Kiprotich Cheruiyot
- Department of Environmental Engineering, National Cheng Kung University, No. 1, University Road, Tainan, 70101, Taiwan; Department of Marine Environmental Engineering, National Kaohsiung University of Science and Technology, No. 142, Haizhuan Road, Nanzih District, Kaohsiung, 81157, Taiwan
| | - Hsi-Hsien Yang
- Department of Environmental Engineering and Management, Chaoyang University of Technology, 168 Jifeng E. Road, Wufeng District, Taichung City, 413310, Taiwan
| | - Lin-Chi Wang
- Department of Environmental Engineering, Chung Yuan Christian University, 200 Chung Pei Road, Chung Li District, Taoyuan City, 32023, Taiwan; Center for Environmental Risk Management, Chung Yuan Christian University, 200 Chung Pei Road, Chung Li District, Taoyuan City, 32023, Taiwan.
| | - Chun-Chi Lin
- Department of Environmental Engineering, National Cheng Kung University, No. 1, University Road, Tainan, 70101, Taiwan
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