Determination of low total mercury concentration and mercury species distribution in flue gases from coal-fired power plants by the sorbent trap method – Validation of the Dowex/AC measuring method
Project Number 341
The public perception for mercury emissions from coal-fired power plants is increasing in Europe. In Germany, an emission limit of 3 µg/m³ is presently in discussion. For new power plants in the Netherlands target values as low as 3 µg/m³ were already demanded during licensing processes.
In Europe, the manual wet chemical method according to DIN EN 13211 (2001-06) is used as a reference method for the determination of the total mercury concentration in flue gases. For concentrations less than 3 µg/m³ this method exhibits a higher measurement uncertainty. It has not been developed for measuring mercury species.
An essential aim of the project is the development of the alternative Dowex/AC sorbent trap method for quantitative, differentiated Hg(el)/Hg(ox) measurements to a stage where it can be used as validated method for the determination of the total and oxidized mercury emissions from coal-fired power plants.
For this, a protocol of the equipment, reagents, sampling and analytical evaluation will be developed. On this basis the short-term sampling version of the Dowex/AC method will be internally calibrated and validated in a field measurement campaign against the standard reference method according to DIN EN 13211. In addition, comparative measurements against the US EPA method 30B and a latest continuous mercury analyser with an enhanced sensitivity shall be carried out.
Another part of the project is to validate the results of the Dowex/AC method for the determination of the mercury species distribution in raw gases upstream of the FGD scrubber. Information on mercury species are of fundamental value for the optimisation of flue gas cleaning processes for the co-removal of mercury, especially in the context of the use of special Hg-active SCR catalysts.
The project will be realised as joint field measuring campaign of E.ON New Build & Technology GmbH, Germany, ENEL Engineering and Innovation SpA, Italy, and GDF Suez/Laborelec, Belgium. These companies significantly support the project realisation with in-kind contributions.
The project is supported by the European Working Group Emissions Monitoring.