Volatile metal species in coal combustion flue gas
Volatile metal species in coal combustion flue gas
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DOI：
10.1021/es015595s
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发表时间：
2002-04-01
影响因子：
11.4
通讯作者：
Donard, OFX
中科院分区：
文献类型：
--
作者：
Pavageau, MP;Pécheyran, C;Donard, OFX
大多数燃烧过程的废水中都会释放金属，并且受到严格的监管。为了提高我们对燃烧过程及其导致的金属向大气排放的了解，我们开发了一种方法，使我们能够区分排放元素的气态和颗粒态。本研究针对燃烧低/中挥发性煤（高品位灰分）的燃煤厂排放的挥发性金属物质的排放进行研究。通过冷冻聚焦取样程序和使用低温填充柱气相色谱法与电感耦合等离子体质谱法作为多元素检测器（LT-GC/ICP-MS）进行检测来研究挥发性金属物质排放的发生。通过静电除尘器下游工厂的常规加热采样线在烟囱中收集样品。气体样品用低温装置捕集并通过 LT-GC/ICP-MS 进行分析。在燃烧过程中，检测到七种挥发性金属物质：三种为硒，一种为锡，两种为汞，一种为铜。热力学计算和实验金属物种尖峰实验表明，燃烧过程中烟气中存在以下挥发性金属物种：COSe、CSSe、CSe2、SeCl2、Hg-0、HgCl2、CuO-CuSO4或CuSO4.H2O以及SnO2或SnCl2。将挥发性物质的量化结果与传统上通过推荐用于烟气燃烧表征的基于标准化撞击器的采样和分析技术获得的结果进行比较。结果表明，采用标准撞击器方法获得的浓度至少比采用低温采样获得的浓度高 10 倍，这表明传统方法可以捕获微气溶胶。还报告并讨论了颗粒中的总金属浓度。
Metals are released in effluents of most of combustion processes and are under intensive regulations. To improve our knowledge of combustion process and their resulting emission of metal to the atmosphere, we have developed an approach allowing us to distinguish between gaseous and particulate state of the elements emitted. This study was conducted on the emission of volatile metallic species emitted from a coal combustion plant where low/medium volatile coal (high-grade ash) was burnt. The occurrence of volatile metal species emission was investigated by cryofocusing sampling procedure and detection using low-temperature packed-column gas chromatography coupled with inductively coupled plasma-mass spectrometry as multielement detector (LT-GC/ICP-MS). Samples were collected in the stack through the routine heated sampling line of the plant downstream from the electrostatic precipitator. The gaseous samples were trapped with a cryogenic device and analyzed by LT-GC/ICP-MS. During the combustion process, seven volatile metal species were detected: three for Se, one for Sn, two for Hg, and one for Cu. Thermodynamic calculations and experimental metal species spiking experiments suggest that the following volatile metal species are present in the flue gas during the combustion process: COSe, CSSe, CSe2, SeCl2, Hg-0, HgCl2, CuO-CuSO4 or CuSO4.H2O, and SnO2 or SnCl2. The quantification of volatile species was compared to results traditionally obtained by standardized impinger-based sampling and analysis techniques recommended for flue gas combustion characterization. Results showed that concentrations obtained with the standard impinger approach are at least 10 times higher than obtained with cryogenic sampling, suggesting the trapping microaerosols in the traditional methods. Total metal concentrations in particles are also reported and discussed.