Department of Mechanical and Industrial Engineering, University of Toronto, 5 King's College Road, Toronto, ON M5S 3G8, Canada.
Environ Sci Technol. 2009 Dec 15;43(24):9294-9. doi: 10.1021/es902409t.
This paper reports the development of an in situ continuous emission monitor (CEM) for measuring elemental mercury (Hg(0)) concentration in the exhaust stream of coal-fired power plants. The instrument is based on the ultraviolet atomic absorption of a mercury lamp emission line by elemental mercury and a light-emitting diode (LED) background correction system. This approach allows an in situ measurement since the absorption of other species such as SO(2) can be removed to monitor the Hg(0) contribution only. Proof of concept was established through a laboratory-based investigation, and a limit of detection, Hg(0), of 2 microg/m(3) was measured for a 1-min averaged sample and an absorption path length of 49 cm. Hg(0) is anticipated to be better than 0.2 microg/m(3) across a 7 m diameter stack. Finally, the apparatus was field-tested in a 230 MW coal-fired power plant. The operability of the measurement in real conditions was demonstrated, leading to the first Hg(0) concentration values recorded by the in situ CEM. Comparison with an accepted standard method is required for validation.
本文介绍了一种用于测量燃煤电厂废气中元素汞（Hg(0)）浓度的原位连续排放监测仪（CEM）的开发。该仪器基于汞灯发射线的紫外原子吸收和发光二极管（LED）背景校正系统。这种方法允许进行原位测量，因为可以去除其他物质（如 SO(2)）的吸收，从而仅监测 Hg(0)的贡献。通过基于实验室的研究证明了概念验证，并在 1 分钟平均样本和 49 厘米吸收路径长度下测量到 2 微克/立方米的检测限Hg(0)。预计在 7 米直径的烟囱中，Hg(0)将优于 0.2 微克/立方米。最后，该仪器在 230MW 燃煤电厂进行了现场测试。证明了在实际条件下测量的可操作性，从而记录了第一个原位 CEM 的 Hg(0)浓度值。需要与公认的标准方法进行比较以验证。
