Dioxins, which are of the most toxic materials on the earth, are principal emitted from waste incineration process. The molecular structures, toxicity parameters, such as toxicity equivalency factor, tolerable daily i...Dioxins, which are of the most toxic materials on the earth, are principal emitted from waste incineration process. The molecular structures, toxicity parameters, such as toxicity equivalency factor, tolerable daily intake and physic-chemical properties of dioxins are briefly summarized. Three formation mechanisms of dioxins in waste incineration process, namely as de novo synthesis, mechanisms involving small organic molecular as precursors and homogenous gas phase reaction mechanism are alto reviewed. The influencing factors for dioxins formation during waste incineration process are also discussed. Three major methods for reducing dioxins emission from waste incineration process are discussed based upon the formation mechanisms and influencing factors. A new waste incineration process with low dioxins emission and low hydrogen chloride corrosion has been proposed based on multi- stage unit operation principal according to formation mechanisms of dioxins and potential production location in waste incinerators.展开更多
The mechanism of removing phosphate by MSWI(municipal solid waste incineration)fly ash was investigated by SEM(scanning electron microscopy)with EDS(energy dispersion spectrum),XRD(X-ray diffraction),FT-IR(Fourier tra...The mechanism of removing phosphate by MSWI(municipal solid waste incineration)fly ash was investigated by SEM(scanning electron microscopy)with EDS(energy dispersion spectrum),XRD(X-ray diffraction),FT-IR(Fourier transform infrared spectroscopy),BET(specific surface area),and BJH(pore size distribution).The results indicate that the removal rate of phosphate(100 mg/L)in 50 mL phosphorus wastewater reaches at 99.9% as the dosage of MSWI fly ash being 0.9000 g under room temperature.The specific surface area of MSWI fly ash is less than 6.1 m2/g and the total pore volume is below 0.021 cm3/g,suggesting that the absorption capacity of calcite is too weak to play an important role in phosphate removal.SEM images show that drastic changes had taken place on its specific surface shape after reaction,and EDS tests indicate that some phosphate precipitates are formed and attached onto MSWI fly ash particles.Chemical precipitation is the main manner of phosphate removal and the main reaction is: 3Ca2++2 PO4 3-+xH2O→Ca3(PO4)2↓·xH2O.Besides,XRD tests show that the composition of MSWI fly ash is complex,but CaSO4 is likely to be the main source of Ca2+.The soluble heavy metals in MSWI fly ash are stabilized by phosphate.展开更多
The destruction of concrete building materials in severely cold regions of the north is more severely affected by freeze-thaw cycles,and the relationship between the mechanical properties and pore structure of concret...The destruction of concrete building materials in severely cold regions of the north is more severely affected by freeze-thaw cycles,and the relationship between the mechanical properties and pore structure of concrete with fine aggregate from municipal solid waste(MSW)incineration bottom ash after freeze-thaw cycles is analyzed under the degree of freeze-thaw hazard variation.In this paper,the gray correlation method is used to calculate the correlation between the relative dynamic elastic modulus,compressive strength,and microscopic porosity parameters to speculate on the most important factors affecting their changes.The GM(1,1)model was established based on the compressive strength of the waste incineration ash aggregate concrete,the relative error between the simulated and actual values in the model was less than 5%,and the accuracy of the model was level 1,indicating that the GM(1,1)model can well reflect the change in the compressive strength of the MSW incineration bottom ash aggregate concrete during freeze-thaw cycles.Using the gray correlation method,the correlation between the relative dynamic elastic modulus,compressive strength,air content,specific surface area,pore spacing coefficient,and pore average chord length was calculated,and the pore spacing coefficient and pore average chord length were determined to be highly correlated with each other.This determination can help analyze and infer the deterioration mechanism of concrete subject to freeze-thaw cycles.These results can provide a theoretical basis for guiding the engineering practice of concrete with fine aggregates of household bottom ash in the northern cold region.展开更多
城市生活垃圾焚烧飞灰(MSWIFA)是城市生活垃圾焚烧产生的副产品之一,处理不当会导致严重的环境问题。采用MSWIFA部分替代水泥制备绿色水泥砂浆(GM)能够实现MSWIFA在建筑材料中的资源化利用。本工作主要研究不同替代率的MSWIFA对GM工作...城市生活垃圾焚烧飞灰(MSWIFA)是城市生活垃圾焚烧产生的副产品之一,处理不当会导致严重的环境问题。采用MSWIFA部分替代水泥制备绿色水泥砂浆(GM)能够实现MSWIFA在建筑材料中的资源化利用。本工作主要研究不同替代率的MSWIFA对GM工作性能、力学性能和耐久性能的影响。此外,本工作还表征了GM的微观孔结构和微观形貌。最后,本工作通过分析1 m 3GM的能耗、碳排放、生产成本,评估了MSWIFA替代水泥制备GM的经济、社会和生态效益。研究表明:(1)MSWIFA的掺入导致GM的抗折强度、抗压强度分别降低了10.54%~29.97%、18.74%~39.54%;(2)硅酸盐水泥可以固化MSWIFA,GM的重金属浸出满足国家规定限值;(3)当MSWIFA的替代率为15%时,1 m 3GM的能耗、碳排放、生产成本分别降低14.90%、14.63%、10.36%,而其工作性能、力学性能、耐久性依然能够满足建筑砂浆要求,表明采用MSWIFA制备GM能够实现该固体废弃物的资源化利用,具有巨大的经济、社会和生态效益。展开更多
For the purpose of solid waste co-disposal and heavy metal stabilization,foam glass-ceramics were produced by using municipal solid waste incineration(MWSI)bottom ash and fly ash as main raw materials,calcium carbonat...For the purpose of solid waste co-disposal and heavy metal stabilization,foam glass-ceramics were produced by using municipal solid waste incineration(MWSI)bottom ash and fly ash as main raw materials,calcium carbonate(CaCO3) as foamer and sodium phosphate(Na3PO4) as foam stabilizer.The influences of the raw material composition,foaming temperature and foaming time on the properties were investigated.Porosity,bulk density,mechanical property and leaching of heavy metals were analyzed accordingly.The product,foamed at 1150℃ for 30 min with 14% fly ash and 74% bottom ash,exhibits excellent comprehensive properties,such as high porosity(76.03%),low bulk density(0.67 g·cm-3) and high compressive strength(10.56 MPa).Moreover,the amount of leaching heavy metals,including Cr,Pb,Cu,Cd and Ni,in foam glass-ceramics is significantly lower than that of the US EPA hazardous waste thresholds.This study not only realizes the integrated utilization of bottom ash and fly ash,but also addresses a new strategy for obtaining foam glass-ceramics.展开更多
A field study and theoretical calculations were performed to clarify the levels, profiles, and distributions of polybrominated dibenzo-p-dioxins and dibenzofurans(PBDD/Fs) in a cement kiln co-processing solid waste, w...A field study and theoretical calculations were performed to clarify the levels, profiles, and distributions of polybrominated dibenzo-p-dioxins and dibenzofurans(PBDD/Fs) in a cement kiln co-processing solid waste, with a focus on the PBDF formation mechanism.The raw materials contributed greatly to input of PBDD/Fs into the cement kiln. The PBDD/F concentrations in the raw materials were much higher than those in particle samples from different process stages in the cement kiln. The PBDD/F concentrations in the clinkers were1.40% of the concentrations in the raw materials, which indicated that the high destruction efficiencies for PBDD/Fs by cement kiln. PBDD/F distribution patterns in particle samples collected from different process stages indicated the cement kiln backend was a major site for PBDD/F formation. PBDFs with high levels of halogenation, such as heptabrominated furans(Hp BDF), were the dominant contributors to the total PBDD/F concentrations and accounted for 42%–73% of the total PBDD/F concentrations in the particle samples. Our results showed that co-processing of municipal solid waste in a cement kiln may influence the congener profile of PBDD/Fs, especially for the higher halogenated PBDD fraction. In addition, there were significant correlations between the decabromodiphenyl ether and heptabrominated furan concentrations, which is an indicator of transformation from polybrominated diphenyl ethers to PBDD/Fs. Theoretical calculations were performed and demonstrated that elimination of HBr and Br_2 from polybrominated diphenyl ethers were the dominant formation pathways for PBDD/Fs. These pathways differed from that for polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs).展开更多
A significant volume of Municipal Solid Waste incineration bottom ash and fly ash (i.e.,incineration residues) are commonly disposed as landfill.Meanwhile,reclamation of landfill sites to create a new land space after...A significant volume of Municipal Solid Waste incineration bottom ash and fly ash (i.e.,incineration residues) are commonly disposed as landfill.Meanwhile,reclamation of landfill sites to create a new land space after their closure becomes an important goal in the current fewer and fewer land availability scenario in many narrow countries.The objective of this study is to reclaim incineration residue materials in the landfill site by using cement and coal fly ash as stabilizers aiming at performing quality check as new developed materials before future construction.Indeed,physical and mechanical properties of these new materials should be initially examined at the micro scale,which is the primary fundamental for construction at larger scale.This research examines quantitative influences of using the combination of cement and coal fly ash at different ratio on the internal structure and ability of strength enhancement of incineration residues when suffering from loading.Couple of industrial and micro-focus X-ray computed tomography (CT) scanners combined with an image analysis technique were utilized to characterize and visualize the behavior and internal structure of the incineration residues-cement-coal fly ash mixture under the series of unconfined compression test and curing period effect.Nine types of cement solidified incineration residues in term of different curing period (i.e.,7,14,28 days) and coal fly ash addition content (i.e.,0%,9%,18%) were scanned before and after unconfined compression tests.It was shown that incineration residues solidified by cement and coal fly ash showed an increase in compression strength and deformation modulus with curing time and coal fly ash content.Three-dimension computed tomography images observation and analysis confirmed that solidified incineration residues including incineration bottom and fly ash as well as cement and coal fly ash have the deliquescent materials.Then,it was studied that stabilized parts play a more important role than spatial void distribution in increment or reduction of compression strength.展开更多
采用高分辨色谱/低分辨质谱联机分析了不同炉型垃圾焚烧炉布袋除尘器飞灰中的二口恶英分布特性。结果表明,燃料组成及飞灰中氯含量对飞灰中二口恶英的浓度均有影响。飞灰中氯含量与灰中的二口恶英含量成正比关系。尽管飞灰中含有大量重...采用高分辨色谱/低分辨质谱联机分析了不同炉型垃圾焚烧炉布袋除尘器飞灰中的二口恶英分布特性。结果表明,燃料组成及飞灰中氯含量对飞灰中二口恶英的浓度均有影响。飞灰中氯含量与灰中的二口恶英含量成正比关系。尽管飞灰中含有大量重金属,但与飞灰中二口恶英的含量并不存在显著的关系。流化床炉与炉排炉布袋除尘器飞灰中二口恶英同系物分布特性不同。飞灰中二口恶英的主要同系物是1,2,3,4,6,7,8 HpCDD(heptachlorinateddibenzo p dioxin),1,2,3,4,6,7,8 HpCDF(heptachlorinateddibenzofuran)和OCDD(octachlorinateddibenzo p dioxin),PCDFs(polychlorinateddibenzofurans),TEQ(toxicequivalencequantity)高于PCDDs含量。初步研究表明,炉排炉飞灰中二口恶英总量及毒性当量(TEQ)大于流化床炉飞灰。展开更多
文摘Dioxins, which are of the most toxic materials on the earth, are principal emitted from waste incineration process. The molecular structures, toxicity parameters, such as toxicity equivalency factor, tolerable daily intake and physic-chemical properties of dioxins are briefly summarized. Three formation mechanisms of dioxins in waste incineration process, namely as de novo synthesis, mechanisms involving small organic molecular as precursors and homogenous gas phase reaction mechanism are alto reviewed. The influencing factors for dioxins formation during waste incineration process are also discussed. Three major methods for reducing dioxins emission from waste incineration process are discussed based upon the formation mechanisms and influencing factors. A new waste incineration process with low dioxins emission and low hydrogen chloride corrosion has been proposed based on multi- stage unit operation principal according to formation mechanisms of dioxins and potential production location in waste incinerators.
基金Projects(51108100,50808184)supported by the National Natural Science Foundation of ChinaProject(100Z007)supported by the Ministry of Education of China+1 种基金Project(200103YB020)supported by Foundation of Guangxi Educational Committee,ChinaProject supported by Guangxi Normal University Education Development Foundation for Young Scholars,China
文摘The mechanism of removing phosphate by MSWI(municipal solid waste incineration)fly ash was investigated by SEM(scanning electron microscopy)with EDS(energy dispersion spectrum),XRD(X-ray diffraction),FT-IR(Fourier transform infrared spectroscopy),BET(specific surface area),and BJH(pore size distribution).The results indicate that the removal rate of phosphate(100 mg/L)in 50 mL phosphorus wastewater reaches at 99.9% as the dosage of MSWI fly ash being 0.9000 g under room temperature.The specific surface area of MSWI fly ash is less than 6.1 m2/g and the total pore volume is below 0.021 cm3/g,suggesting that the absorption capacity of calcite is too weak to play an important role in phosphate removal.SEM images show that drastic changes had taken place on its specific surface shape after reaction,and EDS tests indicate that some phosphate precipitates are formed and attached onto MSWI fly ash particles.Chemical precipitation is the main manner of phosphate removal and the main reaction is: 3Ca2++2 PO4 3-+xH2O→Ca3(PO4)2↓·xH2O.Besides,XRD tests show that the composition of MSWI fly ash is complex,but CaSO4 is likely to be the main source of Ca2+.The soluble heavy metals in MSWI fly ash are stabilized by phosphate.
基金supported by the National Natural Science Foundation of China Project 51868058,52068058Inner Mongolia Natural Science Foundation 2018MS05011Inner Mongolia“Grassland Talent”CYYC5039.
文摘The destruction of concrete building materials in severely cold regions of the north is more severely affected by freeze-thaw cycles,and the relationship between the mechanical properties and pore structure of concrete with fine aggregate from municipal solid waste(MSW)incineration bottom ash after freeze-thaw cycles is analyzed under the degree of freeze-thaw hazard variation.In this paper,the gray correlation method is used to calculate the correlation between the relative dynamic elastic modulus,compressive strength,and microscopic porosity parameters to speculate on the most important factors affecting their changes.The GM(1,1)model was established based on the compressive strength of the waste incineration ash aggregate concrete,the relative error between the simulated and actual values in the model was less than 5%,and the accuracy of the model was level 1,indicating that the GM(1,1)model can well reflect the change in the compressive strength of the MSW incineration bottom ash aggregate concrete during freeze-thaw cycles.Using the gray correlation method,the correlation between the relative dynamic elastic modulus,compressive strength,air content,specific surface area,pore spacing coefficient,and pore average chord length was calculated,and the pore spacing coefficient and pore average chord length were determined to be highly correlated with each other.This determination can help analyze and infer the deterioration mechanism of concrete subject to freeze-thaw cycles.These results can provide a theoretical basis for guiding the engineering practice of concrete with fine aggregates of household bottom ash in the northern cold region.
文摘城市生活垃圾焚烧飞灰(MSWIFA)是城市生活垃圾焚烧产生的副产品之一,处理不当会导致严重的环境问题。采用MSWIFA部分替代水泥制备绿色水泥砂浆(GM)能够实现MSWIFA在建筑材料中的资源化利用。本工作主要研究不同替代率的MSWIFA对GM工作性能、力学性能和耐久性能的影响。此外,本工作还表征了GM的微观孔结构和微观形貌。最后,本工作通过分析1 m 3GM的能耗、碳排放、生产成本,评估了MSWIFA替代水泥制备GM的经济、社会和生态效益。研究表明:(1)MSWIFA的掺入导致GM的抗折强度、抗压强度分别降低了10.54%~29.97%、18.74%~39.54%;(2)硅酸盐水泥可以固化MSWIFA,GM的重金属浸出满足国家规定限值;(3)当MSWIFA的替代率为15%时,1 m 3GM的能耗、碳排放、生产成本分别降低14.90%、14.63%、10.36%,而其工作性能、力学性能、耐久性依然能够满足建筑砂浆要求,表明采用MSWIFA制备GM能够实现该固体废弃物的资源化利用,具有巨大的经济、社会和生态效益。
基金financially supported by the National Natural Science Foundation of China (Nos.51672024 and 51502014)the National Key Research and Development Program of China (No.2017YFB0702304)+1 种基金the Program of China Scholarships Council (No.201806465040)the Fundamental Research Funds for the Central Universities (No.FRF-IC-18-008)
文摘For the purpose of solid waste co-disposal and heavy metal stabilization,foam glass-ceramics were produced by using municipal solid waste incineration(MWSI)bottom ash and fly ash as main raw materials,calcium carbonate(CaCO3) as foamer and sodium phosphate(Na3PO4) as foam stabilizer.The influences of the raw material composition,foaming temperature and foaming time on the properties were investigated.Porosity,bulk density,mechanical property and leaching of heavy metals were analyzed accordingly.The product,foamed at 1150℃ for 30 min with 14% fly ash and 74% bottom ash,exhibits excellent comprehensive properties,such as high porosity(76.03%),low bulk density(0.67 g·cm-3) and high compressive strength(10.56 MPa).Moreover,the amount of leaching heavy metals,including Cr,Pb,Cu,Cd and Ni,in foam glass-ceramics is significantly lower than that of the US EPA hazardous waste thresholds.This study not only realizes the integrated utilization of bottom ash and fly ash,but also addresses a new strategy for obtaining foam glass-ceramics.
基金supported by the National Natural Science Foundation of China(No.21777172)the Collaborative Project supported by Chinese Academy of Sciences and Hebei Academy of Sciences(No.181602)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2016038)
文摘A field study and theoretical calculations were performed to clarify the levels, profiles, and distributions of polybrominated dibenzo-p-dioxins and dibenzofurans(PBDD/Fs) in a cement kiln co-processing solid waste, with a focus on the PBDF formation mechanism.The raw materials contributed greatly to input of PBDD/Fs into the cement kiln. The PBDD/F concentrations in the raw materials were much higher than those in particle samples from different process stages in the cement kiln. The PBDD/F concentrations in the clinkers were1.40% of the concentrations in the raw materials, which indicated that the high destruction efficiencies for PBDD/Fs by cement kiln. PBDD/F distribution patterns in particle samples collected from different process stages indicated the cement kiln backend was a major site for PBDD/F formation. PBDFs with high levels of halogenation, such as heptabrominated furans(Hp BDF), were the dominant contributors to the total PBDD/F concentrations and accounted for 42%–73% of the total PBDD/F concentrations in the particle samples. Our results showed that co-processing of municipal solid waste in a cement kiln may influence the congener profile of PBDD/Fs, especially for the higher halogenated PBDD fraction. In addition, there were significant correlations between the decabromodiphenyl ether and heptabrominated furan concentrations, which is an indicator of transformation from polybrominated diphenyl ethers to PBDD/Fs. Theoretical calculations were performed and demonstrated that elimination of HBr and Br_2 from polybrominated diphenyl ethers were the dominant formation pathways for PBDD/Fs. These pathways differed from that for polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs).
文摘A significant volume of Municipal Solid Waste incineration bottom ash and fly ash (i.e.,incineration residues) are commonly disposed as landfill.Meanwhile,reclamation of landfill sites to create a new land space after their closure becomes an important goal in the current fewer and fewer land availability scenario in many narrow countries.The objective of this study is to reclaim incineration residue materials in the landfill site by using cement and coal fly ash as stabilizers aiming at performing quality check as new developed materials before future construction.Indeed,physical and mechanical properties of these new materials should be initially examined at the micro scale,which is the primary fundamental for construction at larger scale.This research examines quantitative influences of using the combination of cement and coal fly ash at different ratio on the internal structure and ability of strength enhancement of incineration residues when suffering from loading.Couple of industrial and micro-focus X-ray computed tomography (CT) scanners combined with an image analysis technique were utilized to characterize and visualize the behavior and internal structure of the incineration residues-cement-coal fly ash mixture under the series of unconfined compression test and curing period effect.Nine types of cement solidified incineration residues in term of different curing period (i.e.,7,14,28 days) and coal fly ash addition content (i.e.,0%,9%,18%) were scanned before and after unconfined compression tests.It was shown that incineration residues solidified by cement and coal fly ash showed an increase in compression strength and deformation modulus with curing time and coal fly ash content.Three-dimension computed tomography images observation and analysis confirmed that solidified incineration residues including incineration bottom and fly ash as well as cement and coal fly ash have the deliquescent materials.Then,it was studied that stabilized parts play a more important role than spatial void distribution in increment or reduction of compression strength.
文摘采用高分辨色谱/低分辨质谱联机分析了不同炉型垃圾焚烧炉布袋除尘器飞灰中的二口恶英分布特性。结果表明,燃料组成及飞灰中氯含量对飞灰中二口恶英的浓度均有影响。飞灰中氯含量与灰中的二口恶英含量成正比关系。尽管飞灰中含有大量重金属,但与飞灰中二口恶英的含量并不存在显著的关系。流化床炉与炉排炉布袋除尘器飞灰中二口恶英同系物分布特性不同。飞灰中二口恶英的主要同系物是1,2,3,4,6,7,8 HpCDD(heptachlorinateddibenzo p dioxin),1,2,3,4,6,7,8 HpCDF(heptachlorinateddibenzofuran)和OCDD(octachlorinateddibenzo p dioxin),PCDFs(polychlorinateddibenzofurans),TEQ(toxicequivalencequantity)高于PCDDs含量。初步研究表明,炉排炉飞灰中二口恶英总量及毒性当量(TEQ)大于流化床炉飞灰。
