Analysis of trace metal elements and chemical forms from waste combustion and its emissions control

垃圾燃烧中微量金属元素和化学形态分析及其排放控制

基本信息

批准号：
14380279
负责人：
NINOMIYA Yoshihiko
金额：
$ 9.47万
依托单位：
Chubu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14380279/
关键词：
Combustion of waste material Trace metal Cascade impactor CCSEM Fly ash Particulate matter Chemical forms analysis PM2.5 下水汚泥化学形態別分析凝縮性粒子下水汚泥燃焼

项目摘要

Sewage sludge, pulverized coal and the mixture of them were subjected to combustion in a laboratory-scale drop tube furnace to investigate the emission of suspended particulate matter smaller than 10μm (PM_<10>) and to study the correlation of PM_<10> emission with inorganic species of them. Combustion conditions of 1200 to 1450℃ and 0 to 50% atmospheric oxygen concentration were used and all the carbon was consumed under given conditions. The exiting gas, containing the solid products, was initially quenched with N_2 and collected by a water-cooling probe. Subsequently, coarse ash particles were collected by a cyclone. The suspension of ultrafine particles was further diluted with air, and immediately directed to a Low-Pressure-Impactor (LPI) for size-segregated collection. The LPI used here is composed of 13 stages having aerodynamic cut-off diameters ranging from 0.03 to 12.1 μm. Each stage is composed of a quartz or Teflon filter above a substrate and a substrate holder. All the fi … More lters were analyzed by XRF, XRD, Computer controlled scanning electron microscopy (CCSEM), ICP-AES, XPS and TEM to quantify the elemental composition and chemical forms. The properties of PM_<10> were studied including its concentration, particle size distribution, elemental composition and chemical forms.The results indicated that, both the ash content in the fuels and the oxygen content in gas atmosphere affected PM_<10> concentration significantly. With their increasing, PM_<10> concentration was enhanced exponentially. PM_<10> was formed having a lognormal non-gaussian size distribution. Vaporization of the inherent metals plays the paramount role on PM_<10> formation. The inherent alkali, heavy metals and a portion of Si, P, and Fe initially vaporize the resultant metallic vapors undergo oxidization to form their nuclei around 0.03μm, which subsequently undergo coagulation according to the polydisperse coagulation model. Simultaneously, the heterogeneous coagulation between the different species allowed the formation of new chemical species such as alkali/zinc phosphate and sulfates. In addition, a small amount of particles larger than 1.0μm were also found, which was dominated by the refractory metals resulted from the direct transferring of inherent minerals in the fuels. PM_<1+> was formed by the direct transformation of refractory elements in the fuels. Quartz and aluminosilicates within this portion were formed by transformation without phase change. Meanwhile, calcium/iron aluminosilicate in PM_<1+> was formed by the reaction of calcium or iron with aluminosilicate, which led to a sticky surface of the latter compound. Alkali aluminosilicate was formed as melt droplets in combustion and it condensed into large particulates in PM_<1+>. PM_1 is rich in both sulfates and phosphates of vaporized elements. The degree of vaporization of elements is determined by their content (organically bound and included minerals smaller than 10.0 μm) in the raw fuels. The elemental type also affects their vaporization greatly, which decreases in the order of Na > K > Fe > Mg > Ca > Si > Al. This is fairly consistent with the predictions of thermodynamic equilibrium calculations. The vaporized metals reacted with gaseous S0_2, P_2O_5 and SiO to form their compounds. Less

将污泥，粉碎的煤及其混合物在实验室规模的滴管炉中进行组合，以研究小于10μM（PM_ <10>）的悬浮颗粒物的排放，并研究PM_ <10>发射与无机物种的相关性。使用了1200至1450℃的燃烧条件和0至50％的大气氧浓度，并在给定条件下消耗所有碳。最初用N_2淬灭了含有固体产品的出口气体，并通过冷却探针收集。随后，通过旋风收集粗灰颗粒。用空气进一步将超铁颗粒的悬浮液进一步稀释，并立即直接针对低压不良者（LPI）进行大小分离的收集。此处使用的LPI由13个阶段组成，其空气动力学截止直径范围为0.03至12.1μm。每个阶段均由基材上方和基板支架上方的石英或特氟龙滤波器组成。所有FI…通过XRF，XRD，计算机控制的扫描电子显微镜（CCSEM），ICP-AES，XPS和TEM分析了更多的滴度，以量化元素组成和化学形式。研究了PM_ <10>的特性，包括其浓度，粒度分布，元素组成和化学形式。结果表明，燃料中的灰分含量和气体气氛中PM_ <10>浓度的氧含量都受到了显着影响。随着它们的增加，PM_ <10>浓度呈指数增强。 PM_ <10>具有对数正态的非高斯尺寸分布的形成。继承金属的蒸发在PM_ <10>编队上起着至关重要的作用。继承的碱，重金属和一部分Si，P和Fe最初使所得的金属蒸气蒸发会经过氧化，以在0.03μm左右形成其核，随后根据Polydisperseperse凝血模型进行凝血。同时，不同物种之间的异质凝结允许形成新的化学物种，例如碱/锌磷酸盐和硫酸盐。另外，还发现了少量大于1.0μm的颗粒，这是由燃料中继承矿物直接转移的难治性金属所主导的。 PM_ <1+>是通过燃料中的耐火元素的直接转换而形成的。该部分内的石英和铝酸酯是通过转换而没有相变的。同时，通过钙或铁与铝氧化钙的反应形成了PM_ <1+>中的钙/铁铝氧化作用，从而导致后一种化合物的粘性表面。碱铝氧化作用是组合形成的熔体液滴，并在PM_ <1+>中凝结成大型成分。 PM_1富含汽化元素的硫酸盐和磷酸盐。元素的分散程度取决于其含量（有机结合，包括小于10.0μm的矿物质）。元素类型也会极大地影响其分散体，该分散体的降低是Na> k> fe> mg> mg> ca> si> al的顺序。这与热力学平衡计算的预测相当一致。蒸发金属与气态S0_2，P_2O_5和SIO反应形成其化合物。较少的