The company IEM is building a plant that permanently reduces mercury emissions from a lignite-fired power plant, the first plant in Germany that can do this.
Designed to capture mercury: The silo facility (shown in blue) at the Schkopau power plant
Lignite-fired power plants are giants of energy production: they generate enormous amounts of electricity to supply entire regions or cities. Now they have less than a year to adapt to new EU requirements – quite a short time span for the energy giants. What is at issue?
In 2010, the European Council and the European Parliament decided on the IED (Industrial Emissions) Directive. Its aim is, among other things, to reduce mercury emissions from lignite-fired power plants, for which a new limit value was introduced: 10 micrograms per standard cubic metre, more may not be emitted from 1 January 2019. With existing means, most lignite-fired power plants cannot meet this requirement; consequently, they will have to retrofit. Many of the methods that have been tested in recent years have not yet led to the desired result. Now, within a year, the best process for many power plants has to be found and integrated into the existing process. A mission for the process engineers, including the licence to work on it.
The lignite-fired power plant in Schkopau supplies electricity to a neighbouring chemical plant and to Deutsche Bahn, among others. It burns up to six million tonnes of lignite per year. Every standard cubic metre of exhaust gas blown into the air by the power plant contains 15 to 20 micrograms of mercury, about twice the amount prescribed by the EU as of next year.
Dr. Jan Schütze is one of very few experts on mercury capture in power plants. As head of the Mercury Emission Control (MEC) department at IEM, he is mainly responsible for the new process at the Schkopau power plant. At its centre will be a storage tank that uses activated carbon to capture the mercury from the flue gases. It will be about 20 metres high in the middle of the power plant (see picture above). Markus Hertel, project manager at IEM, leads the team, which usually includes seven other IEM employees. Four other companies and some suppliers are also involved. Mercury expert Jan Schütze says: “Compared to other power plant sites in Germany that I know about, the Schkopau site has the most difficult process engineering conditions. The proportion of elemental mercury that is difficult to separate is very high. In addition, the high operating temperature and the high flue gas humidity make mercury separation difficult. Many process approaches there have so far failed at the experimental stage. Whoever can solve the problem in Schkopau can certainly do it anywhere.”
That will become clear at the end of 2018. Until then, IEM’s process should reduce the emitted mercury to a minimum and thus ensure that the power plant complies with the new limit from 2019. This blog will follow the work on the plant and also provide information when the plant is successfully commissioned. The countdown is on.