垃圾焚烧过程中影响重金属分布因素的研究

在转式垃圾焚烧炉和固定床加热炉中，研究了有机垃圾焚烧过程中温度、水分、无机氯及有机氯对几种重金属分布的影响。研究结果表明，焚烧垃圾过程中焚烧温度对重金属分布特性的影响特性不一，重金属锌和铅容易转移到气相中去，而重金属镍和铬大部分是以固态形式残留在底渣中；水能与重金属及其化合物发生反应，引起物质转变，影响重金属的分布；氯的存在也影响重金属的分布特性，氯的参与使重金属更易向飞灰或烟气中迁移。     

不同焚烧温度下开发区污泥焚烧渣分析

在不同焚烧温度条件下采用可控温管式炉焚烧开发区干污泥,对污泥焚烧渣中微观形貌、元素分布、矿物组成以及重金属总量及其形态进行了分析研究。实验结果表明,污泥焚烧渣在焚烧温度为900℃出现明显的结焦现象,在焚烧温度为1 100℃时焚烧渣结焦的微观表面致密。XRD分析发现温度的升高使污泥烧渣中出现NaA lS iO4等性质相当稳定的物质。不同重金属在底渣中的总量分布及其形态特征受焚烧温度的影响程度不同。焚烧温度的提高使污泥中重金属的残渣态比例增高,使污泥焚烧对环境的影响减小。     

市政污泥焚烧过程中重金属迁移转化行为研究进展

焚烧已成为市政污泥处置或资源化利用的重要手段.焚烧过程会改变市政污泥中重金属的化合态和价态,从而影响其迁移转化行为.目前,国内外已对市政污泥焚烧过程中重金属的迁移转化行为开展了大量研究.梳理和归纳了市政污泥特性以及焚烧炉炉型、焚烧温度、停留时间、反应气氛和添加物等工况对重金属迁移转化行为影响的研究进展,并提出了未来仍需...     

污泥焚烧底灰中重金属残留特性的实验研究

利用原子吸收分光光度计和程序控制温升炉研究了沈阳市污水处理厂污泥在不同焚烧工况下重金属Cu、Cr、Cd、Zn、Ni和Pb在焚烧底灰中的残留特性。考察了升温速率、焚烧温度、含水率以及停留时间等因素对重金属在污泥底灰中的残留特性的影响。实验表明 ,Pb、Cd和Cu在灰渣中的残留率随着温度和停留时间的增加而降低。大部分的重金属元素Zn、Cu和Cr残留在灰渣中 ,Cd、Pb和Ni部分残留在灰渣中     

垃圾焚烧重金属迁移特性及其影响因素

综述了城市固体垃圾(MSW)焚烧过程中的Hg、Cd、Pb、Cu、Zn、As和Cr等几种主要重金属污染源在焚烧过程中的迁移特性及其主要影响因素。将重金属在焚烧过程中的迁变归结为:蒸发、气相和表面反应、冷凝成核团聚和飞灰吸附等4个主要过程;而垃圾中重金属的初始浓度、原始垃圾的基体盐分(如A l、S i和K、Na等的存在形式)、垃圾中的C l(PVC和NaC l)和S的含量、垃圾的含水量以及焚烧过程中的运行参数(温度、滞留时间、氧化-还原气氛)等都会对焚烧过程的迁移规律产生影响。     

垃圾焚烧重金属迁移特性及其影响因素

综述了城市固体垃圾（MSW）焚烧过程中的Hg、Cd、Pb、Cu,Zn,As和Cr等几种主要重金属污染源在焚烧过程中的迁移特性及其主要影响因素。将重金属在焚烧过程中的迂变归结为：蒸发、气相和表面反应、冷凝成核团聚和飞灰吸附等4个主要过程；而垃圾中重金属的初始浓度、原始垃圾的基体盐分（如Al、Si和K、Na等的存在形式）、垃圾中的C1（PVc和NaCl）和S的含量、垃圾的含水量以及焚烧过程中的运行参数（温度、滞留时间、氧化一还原气氛）等都会对焚烧过程的迁移规律产生影响。     

CaO/SiO2对流化床焚烧飞灰熔融过程中重金属挥发的影响

对掺煤混烧的流化床焚烧飞灰熔融过程中重金属在气相(吸收率)中和固相(固定率)中的分布进行了研究,并采用HNO3-NaOH2级吸收方式对气相重金属进行了吸收.结果表明,CaO/SiO2(摩尔比)对重金属的迁移行为有重要影响,CaO/SiO2降低,Cd、Pb固定率总体呈上升趋势;2级吸收对气相重金属的吸收有限,大部分重金属主要溶解在HNO3吸收液中,但NaOH吸收液对Cr的吸收效果好于HNO3吸收液;氯对重金属的挥发有重要影响,当重金属以氯化物形式存在时,其挥发受到SiO2的限制.随着SiO2含量增加,挥发率降低.     

污泥焚烧底灰中重金属残留特性的实验研究

利用原子吸收分光光度计和程序控制温升炉研究了沈阳市污水处理厂污泥在不同焚烧工况下重金属Cu,Cr,Cd,Zn,Ni和Pd在焚烧底灰中的残留特性，考察了升温速率，焚烧温度，含水率以及停留时间等因素对重金属在污泥底灰中的残留特性的影响，实验表明，Pd,Cd和Cu在灰渣中的残留率随着渐度和停留时间的增加而降低，大部分的重金属元素Zn,Cr和Cu残留在灰渣中，Cd,Pb和Ni部分残留在灰渣中。     

污泥焚烧中Cd形态转化的热力学平衡模拟

采用热力学平衡分析方法,结合典型污泥成分和焚烧条件预测了污泥焚烧过程中重金属Cd的转化和迁移规律。模拟计算中考虑了主量矿物质与Cl、S对Cd的形态转化的影响。研究结果表明,污泥焚烧过程中,在低温的条件下Cd主要以固体碳酸盐形式存在,随着温度升高,碳酸盐分解为固态CdO,随后有气态Cd(OH)2、Cd和CdO生成,并且在较高温度主要以气态Cd存在。焚烧体系中,矿物质SiO2对Cd的形态转化影响大于其他矿物质,SiO2能与Cd结合生成稳定的CdSiO3,从而可有效抑制含Cd气态污染物的排放。焚烧体系中Cl较易与Cd结合形成CdCl2而导致Cd的挥发,Cl含量的增加促进了Cd在焚烧体系中的挥发。在低温阶段,Cd易与S结合形成固态硫酸盐,抑制了金属的挥发;在高温阶段,金属的形态转化基本不受S的影响,但是可以影响气态金属Cd的生成温度。根据污泥在不同焚烧温度、Cl含量、S含量条件下Cd的不同产物形态,可以对Cd的污染进行有效控制。     

模拟陈腐垃圾掺烧过程中P/Cl/S对6种重金属迁移特性的影响

通过管式炉焚烧实验,探究了在陈腐垃圾与城市生活垃圾(MSW)掺烧过程中,P/Cl/S对6种重金属(Cd、Zn、Ni、Cu、Cr、Pb)迁移规律的影响,并考察了陈腐垃圾掺混比例、含特征元素的添加剂种类及焚烧温度对6种重金属挥发率的影响.结果 表明,当陈腐垃圾掺烧比例与温度相同时,NaH2PO4和Na2SO4的协同作用对Cd挥发有显著的抑制作用,但对Ni、Cu的挥发起促进作用;NaCl对Zn的挥发有明显的抑制作用,但对Cr的挥发起促进作用;而NaCl和Na2SO4的协同作用促进了Pb的挥发.随着焚烧温度在设定范围(600～800℃)内的增加,Cd、Ni、Cr和Pb的挥发率整体呈增加的趋势.相比添加剂种类,陈腐垃圾掺混比例对Cd、Cr、Cu挥发率的影响更显著.本研究结果可为制定有效的重金属控制策略提供参考.     

Effects of chlorides on emissions of toxic compounds in waste incineration: study on partitioning characteristics of heavy metal

Chlorides derived from plastics and food residue content in MSW will affect the formation and partitioning of metal chlorides in the incineration discharges. Our study investigated the effects of waste-derived chlorides on the partitioning of heavy metals in a single-metal combustion system. The results indicate that the heavy metal partitioning behaviors are mainly affected by the presence of chloride, alkaline metals (i.e., Na, K) and moisture in the wastes. The configuration of the metal partitioning is determined by the availability of chlorine, hydrogen, and alkaline metals, or the extent to which the elements may divide from their compounds at a given combustion temperature. The effects of chlorides, including PVC, C2Cl4, FeCl3, NaCl and KCl, were also discussed.     

Bromine in waste incineration partitioning and influence on metal volatilisation

INTENTION, GOAL, SCOPE, BACKGROUND: The halogen bromine is far less abundant than chlorine, but it can be found at high concentrations in special materials like flame retarded plastics. The fate and effects of Br in waste incineration are not well understood. It may have similar implications like Cl for the volatilisation of heavy metals and the formation of low volatile organic compounds. Due to its lower oxidation potential, there is a risk of formation of elementary Br2 in the offgas. OBJECTIVE: Co-combustion tests of different types of Br containing plastic waste materials (up to 22%) and MSW in the TAMARA pilot plant for waste incineration were conducted to investigate the Br partitioning and the influence of Br on metal volatilisation. METHODS: The Br inventory of the fuel mix was elevated to approx. 1 wt-%. All input and output mass flows of the furnace have been sampled and the partitioning of Cl, Br, S, and a number of heavy metals, has been calculated on the basis of closed mass balances. RESULTS AND DISCUSSION: Organically-bound Br was typically released to more than 90% into the raw gas. Elementary Br2 was detected at high Br levels. Its presence was always analysed when all SO2 in the raw gas was oxidised to SO3. Br enhances the volatilisation of metals like K, Zn, Cd, Sn, Sb, and Pb out of the fuel bed principally in the same way as Cl. The tests gave strong indication that the promoting influence of the halogens on metal volatilisation is more pronounced than that of the fuel bed temperature. The volatilised metals are condensated on the fly ashes and are discharged along with the filter ashes. CONCLUSIONS: As long as a surplus of SO2 is present in the raw gas no Br2 is formed. Although the halogen induced transfer out of the fuel bed causes high concentrations of volatile metals in the filter ashes, a recovery is not economically feasible for the time being. The volatilisation gives no rise to metal emission problems as long as efficient dedusting is achieved. RECOMMENDATION AND OUTLOOK: If there is a risk of Br2 formation, in wet scrubbing a reducing agent has to be added to the neutral scrubber for efficient abatement. Filter ashes should be disposed of in a way that enables access for recovery in the future. The exact volatilisation characteristics of the various metals have to be studied in future using specifically tailored experiments.     

Health Effects of Waste Incineration: A Review of Epidemiologic Studies

ABSTRACT

There is an increasing trend toward using incineration to solve the problem of waste management; thus, there are concerns about the potential health impact of waste incineration. A critical review of epidemiologic studies will enhance understanding of the potential health effects of waste incineration and will provide important information regarding what needs to be investigated further. This study reviews the epidemiologic research on the potential health impact of waste incineration. Previous studies are discussed and presented according to their study population, incinerator workers or community residents, and health end points. Several studies showed significant associations between waste incineration and lower male-to-female ratio, twinning, lung cancer, laryngeal cancer, ischemic heart disease, urinary mutagens and pro-mutagens, or blood levels of certain organic compounds and heavy metals. Other studies found no significant effects on respiratory symptoms, pulmonary function,twinning, cleft lip and palate, lung cancer, laryngeal cancer,or esophageal cancer. In conclusion, these epidemiologic studies consistently observed higher body levels of some organic chemicals and heavy metals, and no effects on respiratory symptoms or pulmonary function. The findings for cancer and reproductive outcomes were inconsistent. More hypothesis-testing epidemiologic studies are needed to investigate the potential health effects of waste incineration on incinerator workers and community residents.     

Health effects of waste incineration: a review of epidemiologic studies

There is an increasing trend toward using incineration to solve the problem of waste management; thus, there are concerns about the potential health impact of waste incineration. A critical review of epidemiologic studies will enhance understanding of the potential health effects of waste incineration and will provide important information regarding what needs to be investigated further. This study reviews the epidemiologic research on the potential health impact of waste incineration. Previous studies are discussed and presented according to their study population, incinerator workers or community residents, and health end points. Several studies showed significant associations between waste incineration and lower male-to-female ratio, twinning, lung cancer, laryngeal cancer, ischemic heart disease, urinary mutagens and promutagens, or blood levels of certain organic compounds and heavy metals. Other studies found no significant effects on respiratory symptoms, pulmonary function, twinning, cleft lip and palate, lung cancer, laryngeal cancer, or esophageal cancer. In conclusion, these epidemiologic studies consistently observed higher body levels of some organic chemicals and heavy metals, and no effects on respiratory symptoms or pulmonary function. The findings for cancer and reproductive outcomes were inconsistent. More hypothesis-testing epidemiologic studies are needed to investigate the potential health effects of waste incineration on incinerator workers and community residents.     

The capture of heavy metals from incineration using a spray dryer integrated with a fabric filter using various additives

This study investigated the effects of feedstock additives [polyvinyl chloride (PVC) and NaCl] and spray dryer additives (SiO2, CaCl2, NaHCO3) on heavy metal and fly ash removal efficiencies, and on particle size distribution of heavy metals. A spray dryer with an integrated fabric filter was used as an air pollution control device (APCD). Removal efficiencies for fly ash and heavy metals were greater than 95 and 90%, respectively. When additives of PVC or NaCl were used, the concentration of heavy metals distributed in fly ash apparently varied when the particle diameter was <1 microm. Although the effects of the additives SiO2, CaCl2, and NaHCO3 on the elemental size distribution of Cr were insignificant, these additives did slightly increase concentrations of Cd, Zn, and Pb partitioning in coarser particles (>1 microm).     

SGA对垃圾焚烧飞灰中重金属的固化性能研究

根据EPA1311、HJ／T299—2007、HJ／T300—2007和HJ557—2009等国内外不同标准，研究了深圳某垃圾焚烧发电厂垃圾焚烧飞灰的浸出毒性，探讨了六硫代胍基甲酸（sixthioguanidineacid，SGA）、二甲基二硫代氨基甲酸盐（sodiumdimethyldithiocarbamate，SDD）和Ca（OH）2浓度对垃圾焚烧飞灰中重金属的固定性能的影响。研究结果表明，随着浸提液pH的降低，该厂焚烧飞灰中大部分金属元素的浸出量增大，焚烧飞灰浸出液中的cd、Ni、Ph和zn浓度分别超过国家危险废物鉴别标准（GB5085．3—2007）规定值的4．75倍、1．47倍、6．72倍和2．20倍，属于危险废弃物，必须进行稳定化处理。当固化剂SGA加入量为0．1mol／kg时，稳定化后的重金属浸出浓度已经低于危险废物鉴别标准，且对Cd、Cr、Cu和Pb的固化性能优于SDD和Ca（OH）2；当固化剂SGA、SDD和Ca（OH）2加入量为0．5mol／kg时，稳定化后的焚烧飞灰重金属浸出浓度均低于国家危险废物鉴别标准（GB5085．3-2007）中的规定值。与SDD和Ca（OH）：相比，SGA对垃圾焚烧飞灰中重金属的固化处理更具有优势。     

SGA对垃圾焚烧飞灰中重金属的固化性能研究简

根据EPA 1311、HJ/T 299-2007、HJ/T 300-2007和HJ 557-2009等国内外不同标准，研究了深圳某垃圾焚烧发电厂垃圾焚烧飞灰的浸出毒性，探讨了六硫代胍基甲酸（sixthio guanidine acid，SGA）、二甲基二硫代氨基甲酸盐（sodium dimethyl dithio carbamate，SDD）和Ca（OH）₂浓度对垃圾焚烧飞灰中重金属的固定性能的影响。研究结果表明，随着浸提液pH的降低，该厂焚烧飞灰中大部分金属元素的浸出量增大，焚烧飞灰浸出液中的Cd、Ni、Pb和Zn浓度分别超过国家危险废物鉴别标准（GB5085.3-2007）规定值的4.75倍、1.47倍、6.72倍和2.20倍，属于危险废弃物，必须进行稳定化处理。当固化剂SGA加入量为0.1 mol/kg时，稳定化后的重金属浸出浓度已经低于危险废物鉴别标准，且对Cd、Cr、Cu和Pb的固化性能优于SDD和Ca（OH）₂；当固化剂SGA、SDD和Ca（OH）₂加入量为0.5 mol/kg时，稳定化后的焚烧飞灰重金属浸出浓度均低于国家危险废物鉴别标准（GB 5085.3-2007）中的规定值。与SDD和Ca（OH）₂相比，SGA对垃圾焚烧飞灰中重金属的固化处理更具有优势。     

垃圾焚烧飞灰磷酸洗涤对重金属的固定效应研究

重金属的固定是垃圾焚烧飞灰资源化技术的核心问题.通过系统试验,研究了垃圾焚烧飞灰磷酸洗涤对重金属溶出、后续烧结过程中重金属挥发,以及重金属化学形态变迁的影响.试验结果表明,磷酸洗涤在有效洗脱飞灰中氯盐的情况下,能够显著减少洗涤过程中重金属的溶出,抑制烧结过程中重金属的挥发,从而避免了飞灰处理过程的二次污染;同时,磷酸洗涤使飞灰中的重金属在烧结前后均向更为稳定的化学形态转化,烧结产物中重金属主要以残留态存在,从而提高了烧结产物资源化利用的长期环境安全性.     

Effects of copper chloride on formation of polychlorinated dibenzofurans in model waste incineration in a laboratory-scale fluidized-bed reactor

Combustion experiments in a laboratory-scale fluidized-bed reactor have been performed to clarify the effects of copper chloride as a catalyst on polychlorinated dibenzofurans (PCDFs) formation in municipal waste incineration. We used model wastes with and without copper chloride (CuCl2 x 2H2O) as a catalyst, both of which contained polyvinyl chloride (PVC) as a chlorine source. Combustion temperature was set to 900 degrees C, and the amount of air supplied was twice as much as the theoretical amount. The experimental setup had been carefully planned to ensure avoidance of the influences of previous experiments. Results of these present experiments revealed that copper chloride in the waste increased the amount of PCDFs formed and made the homologue profile shifted towards the highly chlorinated species. Copper chloride contributes to PCDFs formation by promoting chlorination via catalytic reactions, whereby the reaction could be important in that organic matters are chlorinated directly by chlorinated compounds related to Deacon reaction such as copper chloride. It was elucidated that characteristic isomer distribution patterns appeared in case the waste contained copper chloride. It is probable in our experiment with copper chloride that PCDFs are mainly formed via catalytic reactions of copper compounds and carbon.