焚烧过程中氯对重金属形态的影响及脱氯特性研究

目前我国国内还普遍缺乏对危险废弃物焚烧处理的机理研究，尤其是焚烧过程中关于氯、重金属排放及二者之间关系的基础研究。从这一点出发，着重研究了典型危险废弃物之一染料残渣在小型管式炉中焚烧过程中氯化氢的排放特性；并利用化学热力学平衡方法计算了焚烧过程中氯元素对多种常见重金属的排放影响；初步研究了在利用回转窑处理危险废弃物时，两种脱氯剂对烟气中氯的脱除效果。     

氧-燃料燃烧气氛下木屑与聚氯乙烯焚烧时的重金属迁移特性

文章在管式炉中开展燃烧实验,采用ICP-OES技术测试灰渣中的重金属含量,研究在氧-燃料燃烧气氛下木屑与聚氯乙烯(PVC)单独燃烧和混合燃烧过程中重金属的迁移规律,以及在此燃烧条件下有机氯(PVC)与无机氯(NaCl)对重金属迁移特性的影响。研究结果表明:在氧-燃料燃烧气氛下,重金属熔沸点和燃烧温度决定了垃圾组分焚烧过程中重金属的迁移特性;与常规空气燃烧气氛相比,氧-燃料燃烧气氛提高了Pb和Zn的挥发率,降低了Cr的挥发率;木屑与PVC的混烧质量比为5∶5时,混烧对重金属挥发的促进作用要低于质量比例为7∶3和3∶7时;在氧-燃料燃烧气氛下,有机氯对Pb挥发的促进作用大于无机氯。     

垃圾综合治理焚烧过程中重金属的迁移规律

对实际运行中的垃圾焚烧炉灰渣的重金属含量和分布等物理特性进行测试分析，对各种元素间重金属分布特性的相关性及重金属迁移对运行设备造成的影响进行了详细的探讨，为灰渣填埋的重金属控制和化学稳定性措施与灰渣材料化治理利用提供基础。     

电镀污泥热处理重金属的形态变化研究-Sposito法

电镀污泥中重金属的含量及其生物有效性是对环境的重要限制因素。采用改进的Sposito顺序浸提法考察了不同温度(200,400,600,800)℃焚烧电镀污泥残渣中重金属Cu、Ni的赋存形态分布特征。结果表明:焚烧处理具有显著的减量化效应,残渣中的Cu、Ni重金属呈现出富集效益,重金属Cu的残渣态为73.39%,低于Ni(93.03%)。形态分析表明,随着焚烧温度的提高,生物可利用性形态含量呈现下降趋势,实现了不稳定态向稳定态的转化。     

危险废弃物焚烧中重金属迁移特性研究现状

针对我国的危险废弃物研究处于起步阶段,从危险废弃物的定义出发,对危险废弃物中重金属的来源、用焚烧法处理危险废弃物时重金属的迁移和转变特性及其影响因素等方面进行了详细介绍和分析,为帮助人们加深对危险废弃物处理和处置正确性和重要性的认识,进一步研究在焚烧中如何控制重金属的迁移问题提供参考。     

湿污泥热解残渣微观孔隙结构及吸附性能

采用管式炉热解反应器对不同含水率污泥开展高温热解制备残渣样品,采用氮气等温吸附/脱附法分析了含水率对残渣孔隙结构和表面形貌演变的影响规律,探讨了热解残渣作为废液中重金属和染料吸附剂的可行性.研究发现:与干污泥热解残渣相比,湿污泥热解残渣孔隙结构得到更充分发展,孔径2~10,nm的中孔数量明显增加,且在孔径3.75,nm出现单峰值.随着含水率增加至84%,,残渣BET比表面积、累积总孔容积、微孔孔容等呈现减小、增大再减小的趋势;热解残渣对废液中Cu2+、Cr6+以及亚甲基蓝、孔雀石绿染料均有一定的吸附能力.     

垃圾和污泥共燃过程中重金属的赋存迁移规律

采用热力学平衡计算方法,研究了垃圾和污泥焚烧过程Cu、Mn、Zn重金属的迁移规律,考察了温度、HCL、S以及焚烧中污泥水分高低对重金属迁移特性的影响.研究结果表明:除焚烧温度外,HCl是影响重金属迁移的主要因素,HCl的存在会促进难挥发重金属(Cu、Zn)低温时就挥发出来;污泥含水率的降低会增加氯化锌的挥发量,但影响较小,含水率由72％降至12％,氯化锌百分含量增加不到5％.     

基于环保节约理念下垃圾焚烧厂飞灰处理要点分析

由于在生活垃圾和工业化工垃圾的焚烧处理过程中,化学成分和重金属含量严重超标,相关处理问题逐渐引起政府和社会公众的重视。就垃圾焚烧后飞灰自身的特性与稳定性等方面进行探讨,根据飞灰重金属的成分和种类,分析合理的处理方式方法,提出相关建议,以供参考。     

淮南粉煤灰中重金属元素形态分析

采用了BCR提取法研究淮南三大电厂粉煤灰Cd、Co、Cu、Cr、Mn、Ni、Pb、Zn八种元素不同形态。结果表明：不同于土壤及沉积物中的分布,所研究的元素在粉煤灰中均是以残渣态为主,所占比例较高（高于85％）,因此这些微量元素向环境中迁移的量并不高。通过对各元素相关性进行分析,发现粉煤灰中各元素相关性较高．仅有Cd和Cu、Mn和Cu、Mn和Zn之间的相关系数相对较低。但相关系数也在0．8以上。研究表明这种方法具有较高的精度和稳定性,能用于评价粉煤灰中重金属元素的迁移特性．     

城市生活垃圾中再生PVC富氧燃烧重金属迁移特性分析

文章采用化学热力平衡计算方法,研究富氧燃烧气氛下,再生PVC中重金属(Zn,Pb,Cd,Cr,Cu和Ni)的迁移特性,并利用高温管式炉进行实验验证。研究结果表明:燃烧温度对重金属的迁移有显著影响,高温条件下,Cl易于与重金属Zn,Pb生成易挥发的气体;燃烧温度为1 000℃时,20%O2/80%N2与20%O2/80%CO2气氛基本不影响重金属Zn,Pb和Cd的迁移,而在20%O2/80%CO2气氛下,挥发性较弱的重金属Cr,Cu和Ni在底灰中的富集程度更大。燃烧温度为1 000℃时,随着O2浓度的增加,富氧燃烧气氛能够抑制重金属的挥发。     

A particulate model of solid waste incineration in a fluidized bed combining combustion and heavy metal vaporization

This study aims to develop a particulate model combining solid waste particle combustion and heavy metal vaporization from burning particles during MSW incineration in a fluidized bed. The original approach for this model combines an asymptotic combustion model for the carbonaceous solid combustion and a shrinking core model to describe the heavy metal vaporization. A parametric study is presented. The global metal vaporization process is strongly influenced by temperature. Internal mass transfer controls the metal vaporization rate at low temperatures. At high temperatures, the chemical reactions associated with particle combustion control the metal vaporization rate. A comparison between the simulation results and experimental data obtained with a laboratory-scale fluid bed incinerator and Cd-spiked particles shows that the heavy metal vaporization is correctly predicted by the model. The predictions are better at higher temperatures because of the temperature gradient inside the particle. Future development of the model will take this into account.     

垃圾焚烧炉尾部受热面积灰及其抑制方法分析

针对垃圾焚烧过程出现的尾部受热面积灰问题，分析了其形成的机理，着重分析了碱金属对积灰的影响，进而回顾了煤及生物质焚烧过程碱金属吸收剂的研究进展。以往的研究结果显示铝硅类矿物质对防止碱金属积灰有一定的效果，其中高岭土效果较为显著，可尝试作为垃圾焚烧炉内的碱金属脱除剂使用。     

The kinetics of vaporization of a heavy metal from a fluidized waste by an inverse method

This study addresses the emission of heavy metals during the incineration of municipal solid waste. A global method was developed to determine the vaporization rate of the metal from the on-line analysis of exhaust gas. This method differs from direct models, which predict the time course of the metal concentration in the gas from the vaporization rate profile, but which are not practicable because this vaporization rate cannot be measured in real incinerators burning real wastes. The method is based on the determination of the global rate of release of heavy metal from the combustion of model wastes in a fluidized bed. It is an inverse method, which involves only the measured concentration of heavy metal in the exhaust gases and a model developed at the reactor scale. The thermal treatment of model wastes spiked with a metal was performed in a laboratory- scale fluidized bed. In fact, a solid matrix derived from real waste was dosed with Cd, Pb, or Zn and burned to simulate the metal’s release during the incineration of municipal solid waste. An on-line analysis system was linked to the gas outlet of the reactor, and the metal’s vaporization was tracked successfully by continuously measuring by inductively coupled plasma optical emission spectroscopy (ICP-OES) the relative concentration of the metal in exhaust gases. On the theoretical front, a bubbling bed model was developed and validated to calculate the metal’s vaporization rate from its concentration-time profile in the outlet gas. The inverse method consists in identifying these vaporization rates at the particle level from only the on-line diagnostic results and using the model, whatever the waste considered. The data obtained may be used in any process, in which wastes are heated rapidly (several hundreds of degrees per second), as in fluidized beds.     

The fate of chlorine during MSW incineration: Vaporization,transformation, deposition,corrosion and remedies

Municipal solid waste (MSW) incineration plays an important role in waste treatment systems throughout the world, due to the advantages of fast volume reduction by 80–90%, heat recovery, and power generation. However, waste-to-energy (WtE) plants have low electrical efficiency of 15–25%, due to the low steam temperature and pressure used in order to minimize boiler deposition and corrosion problems. Undoubtedly, the high Cl-content in MSW is the reason for the severe corrosion problem. Chlorine also forms volatile compounds with trace metals (e.g., Zn, Pb), and, influences the fate of other key elements, e.g., Na, K, and S.Different from alkali metals in biomass, which have been thoroughly investigated, the behavior of chlorine during MSW incineration has not been systematically and comprehensively studied. Up until now, there are few in-depth studies that have been conducted on the thermal behavior of chlorine or on the remedial measures against Cl-induced problems. An up-to-date review on the behavior of chlorine from incineration via freeboard chemistry to corrosive attack is therefore needed, in order to provide knowledge on process optimization and reactor design, thereby enabling high-efficient energy utilization and safe operation of large-scale WtE units.This review provides a critical summary of the progress of research on chlorine in MSW (origins, species, and analytical methods); the thermal behavior of chlorine, including chlorine vaporization, aerosol formation and transformation (freeboard chemistry), deposit formation, and Cl-initiated corrosion mechanisms. In addition, the interrelationship of chlorine with other key elements (S, Na, K, Zn, Pb), and, the chlorine roadmap in the incineration process is presented, along with the influence of feedstock composition and the temperature of both the flue gas and boiler tube metal on chlorine-induced deposition and corrosion.Mitigation measures against Cl-initiated problems such as Segher boiler prisms, mixed secondary air injection, and eco-tube systems, are also thoroughly discussed. Finally, challenges and further research questions, are identified.     

垃圾焚烧二次污染的危害与防治

本文介绍了垃圾焚烧中二次污染的危害，探讨了垃圾焚烧处理中重金属、HCL及有机氯化物的二次污染的防治技术。     

城市垃圾焚烧处理中的二次污染与防治

该文介绍了城市垃圾焚烧处理中的二次污染问题,着重分析了重金属、HCI及有机氯化物的二次污染的防治技术。     

Release of inorganic trace elements during gasification of wood,straw, and miscanthus

The release of alkali metals, chlorine, sulphur and heavy metals during gasification of four different types of biomass was investigated. The samples were two types of wood (clean and waste wood), miscanthus, and straw. Experiments were conducted in two different setups; in a tube furnace which could be considered as batch experiments, and in an atmospheric lab scale fluidised bed reactor with continuous fuel feed. Molecular beam mass spectrometry was used for on-line analysis of the hot gas. The experimental results reveal that the release of inorganic species like HCl, KCl and H₂S is strongly dependent on other inorganic constituents in the samples, e.g. Si and Ca. In general, the release from herbaceous biomass is much higher than from woody biomass. With the exception of zinc released from miscanthus at temperatures above 900 °C, no heavy metals could be detected. The measurements were accompanied by equilibrium calculations using FactSage 5.5 and the FACT database which are in relatively good agreement with the experimental results.