垃圾焚烧炉飞灰中二(口恶)英的分布特性

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(heptachlorinated dibenzo-p-dioxin),1,2,3,4,6,7,8-HpCDF(heptachlorinated dibenzofuran)和OCDD(octachlorinated dibenzo-p-dioxin),PCDFs(polychlorinated dibenzofurans),TEQ(toxic equivalence quantity)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.     

300 MW等级燃煤机组煤粉炉与循环流化床锅炉汞排放特性比较

选取某地330 MW煤粉炉(PC炉)和350 MW循环流化床锅炉(CFB)的燃煤电厂进行汞排放特性的研究。采用30B法和安大略法对两个燃煤电厂的除尘器入口、除尘器出口、脱硫塔出口和湿式电除尘器出口的烟气进行了取样和汞浓度分析,采集了入炉煤和副产物底渣、飞灰及脱硫石膏样品。通过样品中汞含量的分布,探讨了PC炉与CFB锅炉机组现有污染物控制设备对汞的协同脱除作用。结果表明,350 MW CFB电厂除尘器出口烟气平均汞浓度降低至0.43μg/m~3,布袋除尘器对汞的捕获效率达到98.9%,相应的燃烧副产物中飞灰是汞的主要富集对象。对于330 MW PC炉电厂,除尘器入口和除尘器出口烟气汞浓度均高于350 MW CFB电厂,烟气汞浓度从除尘器入口、除尘器出口到脱硫塔出口依次降低,在脱硫塔出口烟气汞浓度降低至0.42μg/m~3,静电除尘器和湿式脱硫塔对烟气汞的捕获效率分别为75.0%和22.4%,相应的产物中飞灰和脱硫石膏中汞都有一定程度的富集。     

医疗垃圾焚烧飞灰中OCDD/OCDF的球磨机械化学法降解试验研究

利用机械化学法进行含二噁英废弃物的无害化处置,是一个值得关注的研究领域.本研究以去除大部分二噁英及其它有机成分的医疗垃圾焚烧飞灰作为反应基质,添加了八氯代二噁英和呋喃(OCDD/OCDF)后,在自行研制的行星式球磨试验装置上进行了球磨机械化学法降解试验研究.实验球磨两种飞灰分别采自某回转窑热解流化多段焚烧系统和某简易固定床焚烧系统的医疗垃圾焚烧炉布袋除尘器,其中对于简易固定床焚烧处置的飞灰,OCDD和OCDF分别减少了64.7%和63.6%,氯化度由6.86降至5.53.两种飞灰处理后,平均粒径大幅缩小,比表面积、孔容积显著增加,CaCO3强度显著减弱.实验证实飞灰本身的某些组分(CaCO3等)在球磨机械化学处理过程中起到类似氧化钙(CaO)的脱氯还原剂作用,且机械化学法降解二噁英的效果显著.研究结果对实际医疗垃圾焚烧飞灰中二噁英类污染物的脱除具有指导意义.     

垃圾焚烧飞灰理化特性研究

应用能谱分析、灰熔点炉、XRD、压汞仪等仪器手段对国内外8种垃圾焚烧飞灰的成分、熔点、晶相结构、颗粒特性等物理化学性质进行了系统研究。研究表明,飞灰成分因为受原料、炉型、取样位置等因素影响而差异很大。由于飞灰的成分差异导致垃圾焚烧飞灰比煤灰更易于熔融,对熔融处理有利,这主要归因于飞灰中SiO2含量以及SiO2/Al2O3差异,熔点与SiO2含量存在正比关系；添加CaO实现助熔是有条件的,不同飞灰由于焚烧条件和飞灰成分不同导致晶相组成有一定差异；飞灰内部孔径主要分布于0.3 μm～1.5 μm范围内,飞灰的比表面积为20.5 m2/g。     

准东煤流化床气化飞灰的理化特性研究

采用灰熔点测定仪、X射线荧光光谱仪、扫描电镜和热重分析仪等方法,研究了准东煤流化床气化飞灰的灰熔融特性、物理结构和化学组成及气化反应活性。结果表明,准东煤与其流化床气化飞灰中Si O2、Fe2O3、Na2O和Ca O等矿物质含量存在显著的差异,但飞灰的灰熔点与原煤无明显差异。准东煤气化飞灰具有较宽的粒径范围,呈现双峰分布特征,且不同粒径区间飞灰的元素含量存在显著差异。提高气化温度,有利于提高飞灰的气化反应活性。准东煤流化床气化飞灰石墨化程度比煤焦要高,但其孔隙结构更为发达,含有丰富的中孔和中大孔,使得飞灰的气化反应活性高于煤焦。可通过提高气化温度、循环再气化的方法提高气化效率。     

不同反应气氛下准东高钠煤中钠的迁移转化与积灰特性

为了获得循环流化床工艺下不同反应气氛对准东高钠煤中钠的迁移转化与积灰特性的影响,在0.4t/d循环流化床实验装置上开展了相同床温(950℃)下的新疆沙尔湖高钠煤的气化(还原性气氛)与燃烧(氧化性气氛)实验研究。结果表明,气化和燃烧气氛下飞灰与积灰中Na主要以NaCl的形式存在;气化比燃烧更容易将Na、Cl固留在底渣和飞灰中,相应的进入气相中的Na、Cl更少;燃烧气氛下,部分NaCl会被烟气中的SO_2硫化,生成稳定性更高的Na_2SO_4并冷凝在飞灰和积灰棒表面,燃烧过程中产生的飞灰粒径更细,积灰更严重;沙尔湖煤燃烧与气化过程中存在HCl对金属壁面的腐蚀。     

加速溶剂萃取法与索氏提取法对废线路板中二噁英测定的影响

将经过多级破碎分选所得的废线路板粉末过60目筛,以2 mol/L HCl溶液、超纯水洗涤,并用丙酮脱水.将预处理后的滤渣、滤纸填入萃取池,或者用新滤纸包裹后置于索氏提取管内,添加5 μL内标物,分别用加速溶剂萃取法(ASE)或索氏提取(SE)法进行萃取,依次采用多层硅胶柱和活性炭柱对萃取提取物进行净化、洗脱,得到二噁英测试样品.用同位素稀释-高分辨气相色谱-质谱联用仪分析样品中二噁英的含量.考察两种提取方法及不同氯代数对15种13C-2,3,7,8-PCDD/Fs回收率的影响,比较两种方法的准确度和精密度.结果表明,ASE和SE对15种13C-2,3,7,8-PCDD/Fs的回收率分别为54.3%~113.0%和28.3%~77.7%, 实测废线路板中二噁英毒性当量(Toxic equivalent quangtity,TEQ)分别为0.075 ng TEQ/kg和0.266 ng TEQ/kg.在方法精密度允许范围内,ASE相对具有简单快速、溶剂用量少和准确的优势.     

用真比重分离法研究一种飞灰残炭的生成途径和再燃特性

根据煤在足够高温度下，停留时间越长，分子结构的晶格化程度越高，因而反应活性越低，同时真比重也越大的原理，采用重液将一种链条锅炉飞灰中的残炭颗粒富集并按不同真比重分开。各比重组颗粒表面积测定结果符合不同燃尽度焦炭比表面积变化规律；小流化床燃烧实验证明随真比重增大，残炭颗粒本征反应活性降低。说明真比重分离法对于判断飞灰残炭颗粒的形成途径和再燃特性很有效。实验结果表明，链条炉飞灰残炭并不主要由原煤中的细小颗粒形成，由中等和大颗粒原煤形成的飞灰残炭占相当比例；在真比重最大的残炭组中，细小颗粒所拥有的总碳量最大。估计它们是由大颗粒或大块原煤经过炉内高温区、停留时间长，燃烧后期碎裂形成的。     

垃圾焚烧飞灰中重金属的热稳定化条件及机理

研究了生活-农业混合型垃圾焚烧飞灰与单一生活垃圾焚烧飞灰（简称混合型飞灰与单一型飞灰）热处理过程中的重金属挥发特性与稳定化效果，并结合FT-IR、XRD检测手段对稳定化机理进行了探讨。结果表明，单一型飞灰中重金属的挥发性普遍高于混合型飞灰，垃圾源氯含量对重金属的挥发性有明显影响。飞灰中Mn、Cr不易挥发，Zn、Cu较易挥发，Pb、Cd挥发性很强，热处理温度超过1 000 ℃时挥发率都超过50%。800 ℃为相对最优的热处理温度，兼顾了热处理过程重金属稳定化与抑制挥发。800 ℃以上时飞灰形成了稳定的硅酸盐结构体系，是重金属热处理后难以浸出的主要机理。     

660MW燃煤机组锅炉飞灰颗粒物排放特征研究

应用自动烟尘测试仪在沙角C电厂1#炉静电除尘器前进行飞灰颗粒物采集,分析了煤种、负荷对飞灰细颗粒排放特性的影响,同时对飞灰颗粒粒径分布、化学成分、矿物含量和形貌特征等进行了研究。结果表明,机组负荷越高,飞灰颗粒越细,生成的PM1和PM2.5越多,但总的烟尘排放浓度随负荷升高而降低;随着伊泰煤的掺烧比例增大,飞灰颗粒粒径分布向细颗粒区域移动,PM1和PM2.5的含量增大。低负荷时易形成含有熔融小球体的煤胞结构,高负荷时易形成多孔煤胞。高低负荷和不同配煤的燃煤颗粒物矿物成分类似。     

HRGC-LRMS测定垃圾焚烧炉布袋飞灰中的二噁英类物质

利用高分辨气相色谱-低分辨质谱(HRGC-LRMS)测定了某垃圾焚烧厂布袋飞灰中的二(口恶)英类物质,结果表明对于测定二(口恶)英类浓度相对较高的垃圾飞灰而言,采用HRGC-LRMS是一种可行的方法,回收率在74％～114％之间。该飞灰样品中以二(口恶)英为主,呋喃的含量相对较低,二(口恶)英／呋喃值为4.6,二(口恶)英类物质总量为211.7ng／g,折算到毒性当量为0.69ngI-TEQ／g。     

Characteristics of major dioxin/furan congeners in melted slag of ash from municipal solid waste incinerators

Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in slag of fly ash from three municipal solid waste (MSW) incinerators were analyzed to observe any changes in characteristics and distribution of their congeners by melting process. Actual concentration and Toxic Equivalent (TEQ) concentration profiles of 17 major congeners of PCDDs/PCDFs for gas, fly ash and melted slag were compared. The distributions of PCDDs/PCDFs in different streams macroscopically showed similarities with the generally known profiles for emission gas from a municipal waste incinerator. The total concentrations of PCDDs/PCDFs in off-gas and fly ash have been known to be a function of incineration conditions and of air pollution control device utilization; however, their normalized distributions were independent of such conditions. The concentrations of PCDDs/PCDFs in the melted slag of fly ash were not related to the concentrations of PCDDs/PCDFs congeners in fly ash but were rather a function of the melting furnace type and operation. The total amount of PCDDs/PCDFs in the melted slag of fly ash contained almost 150–27,000 times less dioxin than that in fly ash, however, the TEQ of dioxin in the slag was reduced by 435–43,500 times, which could enable them to be utilized as recycled construction materials. In normalized TEQ concentration profiles of 17 congeners of PCDDs/PCDFs, the ratio of PCDFs to PCDDs changed from 1.32 to 2.19 by melting, which showed relatively higher portion of furans left in melted slag than those in fly ash. By comparing reduction ratios of different congeners, PCDDs (dioxins) were relatively easier to destruct than PCDFs (furans) during melting process. The most difficult congener to destruct could be octa-chlorinated dibenzofuran (OCDF) among major congeners. For slag cooling methods, dioxin concentration in TEQ of slow cooled slag by air was four times higher than that of fast cooled slag by water. Thus cooling by water is more appropriate with the added beneficial effect of producing granules/particles, which can be utilized as roadbed materials.     

同位素稀释高分辨气相色谱-高分辨质谱法测定土壤样品中二恶英类化合物的等价毒性当量不确定度的评定

采用同位素稀释高分辨气相色谱-高分辨质谱法（isotope dilution high resolution gas chromatography and high resolution mass spectrometry,ID-HRGC-HRMS）测定土壤样品中二恶英类化合物（polychlorinated dibenzo-p-dioxins and dibenzofurans,PCDD/Fs）的等价毒性当量（toxic equivalent quantity,TEQ）。讨论并确定了测定土壤样品中二恶英类化合物2,3,7,8位异构体不确定度的来源并合成了各异构体的相对标准不确定度;在此基础上,计算了3种等价毒性当量因子（toxic equivalent factor,TEF）框架下土壤样品中PCDD/Fs的TEQ浓度及其合成不确定度和扩展不确定度。     

Triple quadrupole tandem mass spectrometry: A real alternative to high resolution magnetic sector instrument for the analysis of polychlorinated dibenzo-p-dioxins,furans and dioxin-like polychlorinated biphenyls

This paper reports on the optimisation, characterisation, validation and applicability of gas chromatography coupled to triple quadrupole mass spectrometry in its tandem operation mode (GC-QqQ(MS/MS) for the quantification of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs, dioxins) and dioxin-like polychlorinated biphenyls (DL-PCBs) in environmental and food matrices. MS/MS parameters were selected to achieve the high sensitivity and selectivity required for the analysis of this type of compounds and samples. Good repeatability for areas (RSD = 1–10%, for PCDD/Fs and DL-PCBs) and for ion transition ratios (RSD = 0.3–10%, for PCDD/Fs, and 0.2–15%, for DL-PCBs) and low instrumental limits of detection, 0.07–0.75 pg μL⁻¹ (for dioxins) and 0.05–0.63 pg μL⁻¹ (for DL-PCBs), were obtained. A comparative study of the congener specific determination using both GC-QqQ(MS/MS) and gas chromatography-high resolution mass spectrometry (GC-HRMS) was also performed by analysing several fortified samples and certified reference materials (CRMs) with low (feed and foodstuffs), median (sewage sludge) and high (fly ash) toxic equivalency (TEQ) concentration levels, i.e. 0.60, 1.83, 72.9 and 3609 pg WHO-TEQ(PCDD/Fs) g⁻¹. The agreement between the results obtained for the total TEQs (dioxins) on GC-QqQ(MS/MS) and GC-HRMS in all the investigated samples were within the range of ±4%, and that of DL-PCBs at concentration levels of 0.84 pg WHO-TEQs (DL-PCBs) g⁻¹, in the case of feedstuffs, was 0.11%. Both instrumental methods have similar and comparable linearity, precision and accuracy. The GC-QqQ(MS/MS) sensitivity, lower than that of GC-HRMS, is good enough (iLODs in the down to low pg levels) to detect the normal concentrations of these compounds in food and environmental samples. These results make GC-QqQ(MS/MS) suitable for the quantitative analysis of dioxins and DL-PCBs and a real alternative tool to the reference sector HRMS instruments.     

Use of Carbon-13 Labelled Dioxins Mixture for Analysis of Polychlorinated Dibenzo-p-Dioxins in Environmental Samples by GC-MS

Abstract

Positive identification and quantitation of polychlorinated dibenzo-p-dioxins (PCDD) in complicated environmental samples is described using a C-13 labelled dioxin mixture as an internal reference standard. Environmental samples are spiked with the C-13 labelled dioxin mixture and monitored for labelled and unlabelled dioxins using GC-MS in the electron impact selected ion monitoring (EISIM) mode. The C-13 labelled dioxin mixture and a municipal solid waste (MSW) incinerator fly ash extract show the same number of isomers in each tetra to octa-chlorodioxin congener groups. Quantitation of the C-13 labelled dioxin mixture was carried out using a reference standard mixture of unlabelled dioxins consisting of at least one isomer for each congener group. The C-13 labelled dioxin standard is highly useful for the determination of retention windows for tetra- to octa-chlorodioxins, identification of dioxins in each congener group, and calculation of the recovery of dioxins in samples that require extensive sample clean-up prior to GC-MS analysis. Its application for retention time window determination and as an internal reference standard for quantitation of dioxins in MSW incinerator fly ash extract and identification of dioxins in a complex sample from a PCB fire is demonstrated.     

高分辨气相色谱/质谱法分析新闻纸和复印纸中的二恶英

随机选择空白的和经过印刷的新闻纸和复印纸,粉碎后用溶剂提取并经多步色谱柱纯化,采用同位素稀释、高分辨气相色谱/高分辨质谱(HRGC/HRMS)联用技术分析了其中的二含量。结果表明:新闻纸中二的总量高于复印纸,但是毒性当量却低于复印纸;经过印刷的新闻纸和复印纸中二的含量均高于空白的新闻纸和复印纸;新闻纸和复印纸中相同二异构体的含量 是不同的。空白的和经过印刷的新闻纸中二毒性当量分别为0.48 ng/kg和0.61 ng/kg,而空白的和经过印刷的复印纸中二恶英毒性当量分别为0.74 ng/kg和0.79     

Uncertainty assessment of polychlorinated dibenzo-p-dioxins and dibenzofuran and dioxin-like polychlorinated biphenyl analysis in stationary source sample emissions in accordance with the impending European standard EN-1948 using fly ashes

The analysis of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) present in stack gas emissions and solid residues from incinerators will be mandatory in the foreseeable future. European standard EN-1948 is in the process of being updated through the addition of a new Part 4 related to the analysis of the 12 dl-PCBs. Therefore, either a comprehensive and reliable method capable of analyzing all of these 29 compounds (12 dl-PCBs and 17 2,3,7,8-PCDD/Fs) needs to be developed, or the existing PCDD/F analytical procedure must be adapted to include the dl-PCBs. This study has taken the latter approach of modifying PCDD/F methodology and in particular the fractionation step, by isolating dioxins and dl-PCBs into separate fractions ready for high resolution gas chromatography coupled to high resolution mass spectrometry (HRGC/HRMS) analysis. Results obtained from the analysis of Certified Reference Materials (CRM-490 and CRM-615) and fly ashes from the European Committee for Standardization (CEN) intercalibration study demonstrated that the proposed methodology is appropriate to determine the dl-PCBs in accordance with the impending European standard EN-1948. Uncertainty values obtained during the validation of the analytical methodology were 13% total I-TEQ (International Toxic Equivalent) for PCDD/Fs and 31% total WHO-TEQ (World Health Organization Toxic Equivalent) in the case of dl-PCBs. In addition, ‘real’ samples such as emissions and fly ashes were successfully analyzed following the proposed analytical method.     

高分辨气相色谱/质谱法分析新闻纸和复印纸中的二噁

随机选择空白的和经过印刷的新闻纸和复印纸 ,粉碎后用溶剂提取并经多步色谱柱纯化 ,采用同位素稀释、高分辨气相色谱 /高分辨质谱 (HRGC/HRMS)联用技术分析了其中的二含量。结果表明 :新闻纸中二的总量高于复印纸 ,但是毒性当量却低于复印纸 ;经过印刷的新闻纸和复印纸中二的含量均高于空白的新闻纸和复印纸 ;新闻纸和复印纸中相同二异构体的含量是不同的。空白的和经过印刷的新闻纸中二毒性当量分别为 0 4 8ng/kg和 0 6 1ng/kg,而空白的和经过印刷的复印纸中二毒性当量分别为 0 74ng/kg和 0 79ng/kg。所有样品中添加的13 C标记的 2 ,3,7,8位取代的二回收率均在 4 9 82 %至 131 34%之间。