In Situ Optical Absorption Mercury Continuous Emission Monitor

详细信息    查看全文

• 作者：Jrô ; me Thiebaud ; Murray J. Thomson ; Reza Mani ; William H. Morrow ; Eric A. Morris ; Charles Q. Jia
• 刊名：Environmental Science & Technology
• 出版年：2009
• 出版时间：December 15, 2009
• 年：2009
• 卷：43
• 期：24
• 页码：9294-9299
• 全文大小：237K
• 年卷期：v.43,no.24(December 15, 2009)
• ISSN：1520-5851

文摘

This paper reports the development of an in situ continuous emission monitor (CEM) for measuring elemental mercury (Hg⁰) 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 SO₂ can be removed to monitor the Hg⁰ contribution only. Proof of concept was established through a laboratory-based investigation, and a limit of detection, [Hg⁰]_min, of 2 μg/m³ was measured for a 1-min averaged sample and an absorption path length of 49 cm. [Hg⁰]_min is anticipated to be better than 0.2 μg/m³ 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 Hg⁰ concentration values recorded by the in situ CEM. Comparison with an accepted standard method is required for validation.