A new measuring instrument for monitoring mercury

The combustion gases of power and production plants under close monitoring

The cooperation between VTT and Gasmet Technologies Oy has produced a measuring instrument for continuous monitoring of mercury. Many of the problems with the earlier instruments have been overcome by applying the best of the newest technologies. The instrument fulfils the latest provisions for the measuring of mercury laid down in legislation and, particularly, the new US requirements for the continuous monitoring of mercury.

Obligations under the EU and US legislation

Combustion gases produced by coal-fired power plants and waste incineration plants may include poisonous heavy metals, such as mercury. The steel industry is also responsible for emissions that may contain mercury. Mercury emissions are restricted by legislation, such as the EU Directive 2000/76/EC on the incineration of waste, and certain countries, such as Germany, oblige plants to monitor their mercury emissions continuously. In the USA an Act on the obligation of coal-fired plants to monitor mercury continuously (Clean Air Mercury Rule, CAMR) entered into force this year. This opens up a significant market for measuring instrument suppliers.

Even temporary excesses can be detected

Even without legal obligations, operators often need data on the temporary changes to the mercury content in combustion gases. Continuous monitoring is able to detect malfunctions in the purification systems and temporary exceeding of the emission limits.

Among the drawbacks to the existing commercially available mercury monitoring systems are complicated sample processing, instability and a frequent need to replace various expensive parts. In the CMM (Continuous Mercury Monitoring System) measuring instrument developed by VTT and Gasmet Technologies Oy the majority of the earlier problems have been avoided by new solutions.

High sensitivity combined with field capability

The instrument is based on Cold Vapour Atomic Fluorescence (CVAF) technology. The method enables high sensitivity and direct diluting sampling without collection of mercury. The measuring instrument is equipped with automatic calibration, has a robust structure and is suitable for use in the field. The instrument has been successfully tested in field conditions at Ekokem Oy’s hazardous waste incineration plant and long-terms tests in California are beginning.

 


Additional information

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